Transmission method of indication information, message transmission method and related device

Abstract

The application provides a transmission method of indication information, a message transmission method and related devices, and the method comprises the following steps: an intermediate session management network element sends third indication information to a target user plane network element according to second indication information from a session management network element, so that the target user plane network element buffers uplink data packets according to the third indication information; when the session management network element learns that the target application network element has completed the switching, the session management network element can send fourth indication information to the intermediate session management network element, so that the intermediate session management network element sends fifth indication information to the target user plane network element according to the fourth indication information, and then the target user plane network element forwards the uplink data packets according to the fifth indication information, which avoids the loss of data packets and improves the reliability of data packet transmission.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a method for transmitting instruction information, a message transmission method, and related apparatus. Background Technology

[0002] In 5G networks, data streams from terminal devices can be split using uplink classifiers (UL CL) or branching points (BP). This allows some data streams to be forwarded from local session anchors closer to the terminal device's access location, while other data streams are forwarded from remote session anchors farther away. This shortens the packet forwarding path and reduces latency when application servers are deployed at lower locations.

[0003] When a terminal device moves, the uplink splitter and the local session anchor point may change simultaneously, or the splitter point and the local session anchor point may change simultaneously. In such cases, packet loss may occur. Therefore, how to avoid packet loss and improve the reliability of packet transmission has become an urgent problem to be solved. Summary of the Invention

[0004] This application provides a method for transmitting instruction information, a method for transmitting messages, and related apparatus, which can avoid data packet loss and improve the reliability of data packet transmission.

[0005] Firstly, a method for transmitting indication information is provided. The method includes: an intermediate session management network element sending first indication information to a session management network element, the first indication information indicating that the intermediate session management network element has inserted a target user plane network element and a target user plane network element, and has deleted a source user plane network element and a source user plane network element. Next, the intermediate session management network element receives second indication information from the session management network element, the second indication information indicating that the target user plane network element buffers uplink data packets. Based on the second indication information, the intermediate session management network element sends third indication information to the target user plane network element, the third indication information indicating that the target user plane network element buffers uplink data packets. The intermediate session management network element receives fourth indication information from the session management network element, the fourth indication information indicating that the target user plane network element forwards uplink data packets. Based on the fourth indication information, the intermediate session management network element sends fifth indication information to the target user plane network element, the fifth indication information indicating that the target user plane network element forwards uplink data packets. In other words, the intermediate session management network element can send a first indication to the session management network element, enabling the session management network element to know that the intermediate session management network element has inserted the target user plane network element and the target user plane network element, and that the source user plane network element and the source user plane network element have been deleted. This allows the intermediate session management network element to send a third indication to the target user plane network element based on the second indication from the session management network element, thus instructing the target user plane network element to buffer uplink data packets according to the third indication. Simultaneously, when the session management network element learns that the target application network element has completed the handover, it can send a fourth indication to the intermediate session management network element, enabling the intermediate session management network element to send a fifth indication to the target user plane network element based on the fourth indication, thus instructing the target user plane network element to forward uplink data packets according to the fifth indication. Understandably, because the target user plane network element does not forward uplink data packets before the target application network element completes the handover, but instead buffers the uplink data packets before the target application network element completes the handover, the uplink data packets are not forwarded, thus avoiding uplink data packet loss. In addition, since the target user plane network element forwards the uplink data packet only after the target application network element has completed the handover, the uplink data packet can be forwarded to the target application network element, which improves the reliability of data packet transmission.

[0006] Optionally, the method further includes: the intermediate session management network element sending a first packet forwarding control protocol request message to the user plane network element, wherein the first packet forwarding control protocol request message includes a first packet detection rule (PDR) and a first packet forwarding action rule (FAR).

[0007] Wherein, if the user plane network element is the source diversion user plane network element, the first data packet detection rule is the rule corresponding to the data packet from the target diversion user plane network element detected by the source diversion user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packet from the target diversion user plane network element forwarded by the source diversion user plane network element to the source user plane network element.

[0008] In this scenario, if the user plane network element is the target offloading user plane network element, the first data packet detection rule is the rule corresponding to the data packets from the target access network device detected by the target offloading user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packets from the target access network device forwarded by the target offloading user plane network element to the source offloading user plane network element. That is, the intermediate session management network element can send a first data packet forwarding control protocol request message to either the source offloading user plane network element or the target offloading user plane network element. This first data packet forwarding control protocol request message includes the first data packet detection rule and the first data packet forwarding rule, enabling either the source offloading user plane network element or the target offloading user plane network element to detect data packets according to the first data packet detection rule and forward data packets according to the first data packet forwarding rule. This ensures that uplink data packets are sent from the source user plane network element to the source application network element before the target application network element completes the handover, avoiding the loss and interruption of uplink data packets from the terminal device and improving the continuity and reliability of data packet transmission.

[0009] Optionally, the method further includes: the intermediate session management network element receiving a second data packet detection rule, a second data packet forwarding rule, and a sixth indication information from the session management network element. The sixth indication information indicates one or more of the following: the second data packet detection rule is the rule corresponding to the data packet detected by the source or target user plane network element; the second data packet forwarding rule is the rule corresponding to the data packet forwarding by the source or target user plane network element. In other words, the intermediate session management network element can receive the second data packet detection rule, the second data packet forwarding rule, and the sixth indication information from the session management network element, enabling the intermediate session management network element to know one or more of the following: the second data packet detection rule is the rule corresponding to the data packet detected by the source or target user plane network element; the second data packet forwarding rule is the rule corresponding to the data packet forwarding by the source or target user plane network element.

[0010] Optionally, if the user plane network element is the target offloading user plane network element, the first packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the target offloading user plane network element and the Internet Protocol address of the target offloading user plane network element to the second packet detection rule according to the sixth instruction information. The first packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the second packet forwarding rule according to the sixth instruction information.

[0011] If the user plane network element is a source-splitting user plane network element, the first packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source-splitting user plane network element and the Internet Protocol address of the source-splitting user plane network element to the second packet detection rule according to the sixth instruction information. The first packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source user plane network element and the Internet Protocol address of the source user plane network element to the second packet forwarding rule according to the sixth instruction information.

[0012] As can be seen, in the above technical solution, since the first data packet detection rule also includes the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element, and the first data packet forwarding rule also includes the tunnel endpoint identifier and the Internet Protocol address of the source offloading user plane network element, the target offloading user plane network element can receive and detect data packets based on the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element. Furthermore, it can establish a tunnel with the source offloading user plane network element based on the tunnel endpoint identifier and the Internet Protocol address of the source offloading user plane network element, enabling data packets to be transmitted through the tunnel and avoiding the loss and interruption of uplink data packets from the terminal device. Similarly, since the first data packet detection rule also includes the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element, and the first data packet forwarding rule also includes the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element, the source user plane network element can receive and detect data packets based on the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element. It can also establish a tunnel with the source user plane network element based on the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element, so that data packets can be transmitted through the tunnel, avoiding the loss and interruption of uplink data packets of the terminal device.

[0013] Secondly, a message transmission method is provided, the method comprising: an intermediate session management network element sending a third data packet forwarding control protocol request message to a user plane network element, the third data packet forwarding control protocol request message including a third data packet detection rule and a third data packet forwarding rule.

[0014] Wherein, if the user plane network element is the source diversion user plane network element, the third data packet detection rule is the rule corresponding to the data packet from the remote user plane network element detected by the source diversion user plane network element, and the third data packet forwarding rule is the rule corresponding to the data packet from the remote user plane network element forwarded by the source diversion user plane network element to the target diversion user plane network element; or, the third data packet detection rule is the rule corresponding to the data packet from the source user plane network element detected by the source diversion user plane network element, and the third data packet forwarding rule is the rule corresponding to the data packet from the source user plane network element forwarded by the source diversion user plane network element to the target diversion user plane network element.

[0015] In this configuration, if the user plane network element is the target offloading user plane network element, the third data packet detection rule is the rule corresponding to the data packets from the source offloading user plane network element detected by the target offloading user plane network element, and the third data packet forwarding rule is the rule corresponding to the data packets from the source offloading user plane network element forwarded by the target offloading user plane network element to the target access network device. That is, the intermediate session management network element can send a third data packet forwarding control protocol request message to either the source or target offloading user plane network element. This request message includes both the third data packet detection rule and the third data packet forwarding rule, enabling either the source or target offloading user plane network element to detect data packets according to the third data packet detection rule and forward data packets according to the third data packet forwarding rule. This avoids the loss and interruption of downlink data packets from the terminal device, improving the continuity and reliability of data packet transmission.

[0016] Optionally, the method further includes: the intermediate session management network element receiving a fourth data packet detection rule, a fourth data packet forwarding rule, and seventh indication information from the session management network element. The seventh indication information indicates one or more of the following: the fourth data packet detection rule is the rule corresponding to the data packet detected by the source or destination user plane network element; the fourth data packet forwarding rule is the rule corresponding to the data packet forwarded by the source or destination user plane network element.

[0017] As can be seen, in the above technical solution, the intermediate session management network element can receive the fourth data packet detection rule, the fourth data packet forwarding rule, and the seventh indication information from the session management network element, so that the intermediate session management network element can know one or more of the following: the fourth data packet detection rule is the rule corresponding to the data packet detected by the source diversion user plane network element or the target diversion user plane network element; the fourth data packet forwarding rule is the rule corresponding to the data packet forwarded by the source diversion user plane network element or the target diversion user plane network element.

[0018] Optionally, if the user plane network element is the target offloading user plane network element, the third packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element to the fourth packet detection rule according to the seventh instruction information. The third packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target access network device to the fourth packet forwarding rule according to the seventh instruction information.

[0019] If the user plane network element is the source offloading user plane network element, the third packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the source offloading user plane network element to the fourth packet detection rule according to the seventh instruction information. The third packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element to the fourth packet forwarding rule according to the seventh instruction information. It is understandable that because the third packet detection rule also includes the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element, and the third packet forwarding rule also includes the tunnel endpoint identifier and the Internet Protocol address of the target access network device, the target offloading user plane network element can receive and detect packets based on these identifiers. It can also establish a tunnel with the target access network device based on the tunnel endpoint identifier and the Internet Protocol address of the target access network device, allowing packets to be transmitted through the tunnel and preventing the loss of downlink packets from the terminal device. Similarly, since the third packet detection rule also includes the tunnel endpoint identifier and Internet Protocol (IP) address of the source user plane network element, and the third packet forwarding rule also includes the tunnel endpoint identifier and IP address of the target user plane network element, the source user plane network element can receive and detect packets based on the tunnel endpoint identifier and IP address of the source user plane network element, and establish a tunnel with the target user plane network element based on the tunnel endpoint identifier and IP address of the target user plane network element. This allows packets to be transmitted through the tunnel, avoiding the loss of downlink packets from the terminal device.

[0020] Thirdly, a method for transmitting indication information is provided. The method includes: a session management network element receiving first indication information from an intermediate session management network element. The first indication information indicates that the intermediate session management network element has inserted a target user plane network element and a target user plane network element, and has deleted a source user plane network element and a source user plane network element. The session management network element sends second indication information to the intermediate session management network element based on the first indication information. The second indication information indicates that the target user plane network element buffers uplink data packets. The session management network element sends fourth indication information to the intermediate session management network element. The fourth indication information indicates that the target user plane network element forwards uplink data packets. The fourth indication information is sent by the session management network element after it learns that the target application network element has completed the handover. In other words, the session management network element can receive the first indication information from the intermediate session management network element, enabling it to know that the intermediate session management network element has inserted the target user plane network element and the target user plane network element, and that the source user plane network element and the source user plane network element have been deleted. Based on the first indication information, the session management network element sends the second indication information to the intermediate session management network element. This allows the target user plane network element to buffer uplink data packets before the target application network element completes the handover, preventing uplink data packets from being forwarded and avoiding their loss. Simultaneously, the session management network element sends the fourth indication information to the intermediate session management network element, ensuring that the target user plane network element only forwards uplink data packets after the target application network element completes the handover. This ensures that uplink data packets can be forwarded to the target application network element, improving the reliability of data packet transmission.

[0021] Optionally, the method further includes: the session management network element sending a second data packet detection rule, a second data packet forwarding rule, and a sixth indication information to the intermediate session management network element. The sixth indication information indicates one or more of the following: the second data packet detection rule is the rule corresponding to the data packet detected by the source or target user plane network element; the second data packet forwarding rule is the rule corresponding to the data packet forwarding by the source or target user plane network element. That is, the session management network element can send the second data packet detection rule, the second data packet forwarding rule, and the sixth indication information to the intermediate session management network element, so that the intermediate session management network element can know one or more of the following: the second data packet detection rule is the rule corresponding to the data packet detected by the source or target user plane network element; the second data packet forwarding rule is the rule corresponding to the data packet forwarding by the source or target user plane network element.

[0022] Fourthly, a method for transmitting indication information is provided. This method includes: a user plane network element receiving third indication information from an intermediate session management network element, the third indication information instructing the user plane network element to buffer uplink data packets; and the user plane network element receiving fifth indication information from the intermediate session management network element, the fifth indication information instructing the user plane network element to forward uplink data packets. In other words, the user plane network element can receive the third indication information from the intermediate session management network element instructing it to buffer uplink data packets, enabling the target user plane network element to buffer uplink data packets before the target application network element completes the handover, thus preventing the uplink data packets from being forwarded and avoiding their loss. Simultaneously, the user plane network element can receive the fifth indication information from the intermediate session management network element instructing it to forward uplink data packets, enabling the target user plane network element to forward uplink data packets only after the target application network element completes the handover, ensuring that the uplink data packets can be forwarded to the target application network element and improving the reliability of data packet transmission.

[0023] Optionally, the method further includes: the user plane network element receiving a first data packet forwarding control protocol request message from the intermediate session management network element, wherein the first data packet forwarding control protocol request message includes a first data packet detection rule and a first data packet forwarding rule.

[0024] Wherein, if the user plane network element is the source diversion user plane network element, the first data packet detection rule is the rule corresponding to the data packet from the target diversion user plane network element detected by the source diversion user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packet from the target diversion user plane network element forwarded by the source diversion user plane network element to the source user plane network element.

[0025] In this configuration, if the user plane network element is the target offloading user plane network element, the first data packet detection rule is the rule corresponding to the data packets from the target access network device detected by the target offloading user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packets from the target access network device forwarded by the target offloading user plane network element to the source offloading user plane network element. That is, either the source offloading user plane network element or the target offloading user plane network element can receive a first data packet forwarding control protocol request message from the intermediate session management network element. This message includes the first data packet detection rule and the first data packet forwarding rule, enabling either the source offloading user plane network element or the target offloading user plane network element to detect data packets according to the first data packet detection rule and forward data packets according to the first data packet forwarding rule. This ensures that uplink data packets are sent from the source user plane network element to the source application network element before the target application network element completes the handover, avoiding the loss and interruption of uplink data packets from the terminal device and improving the continuity and reliability of data packet transmission.

[0026] Optionally, if the user plane network element is the target offloading user plane network element, the first packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the target offloading user plane network element and the Internet Protocol address of the target offloading user plane network element to the second packet detection rule according to the sixth instruction information. The first packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the second packet forwarding rule according to the sixth instruction information.

[0027] If the user plane network element is a source-splitting user plane network element, the first packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source-splitting user plane network element and the Internet Protocol address of the source-splitting user plane network element to the second packet detection rule according to the sixth instruction information. The first packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source user plane network element and the Internet Protocol address of the source user plane network element to the second packet forwarding rule according to the sixth instruction information.

[0028] The sixth indication information is used to indicate one or more of the following: the second data packet detection rule is the rule corresponding to the detection of data packets by the source or target user plane network element; the second data packet forwarding rule is the rule corresponding to the forwarding of data packets by the source or target user plane network element. It is understandable that, since the first data packet detection rule also includes the tunnel endpoint identifier and the Internet Protocol (IP) address of the target user plane network element, and the first data packet forwarding rule also includes the tunnel endpoint identifier and the IP address of the source user plane network element, the target user plane network element can receive and detect data packets based on the tunnel endpoint identifier and the IP address of the target user plane network element. It can also establish a tunnel with the source user plane network element based on the tunnel endpoint identifier and the IP address of the source user plane network element, allowing data packets to be transmitted through the tunnel and avoiding the loss of uplink data packets from the terminal device. Similarly, since the first data packet detection rule also includes the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element, and the first data packet forwarding rule also includes the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element, the source user plane network element can receive and detect data packets based on the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element. It can also establish a tunnel with the source user plane network element based on the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element, so that data packets can be transmitted through the tunnel, avoiding the loss of uplink data packets of the terminal device.

[0029] Fifthly, a message transmission method is provided, the method comprising: a user plane network element receiving a third data packet forwarding control protocol request message from an intermediate session management network element, the third data packet forwarding control protocol request message including a third data packet detection rule and a third data packet forwarding rule.

[0030] If the user plane network element is a source offloading user plane network element, the third data packet detection rule is the rule corresponding to the data packets from the remote user plane network element detected by the source offloading user plane network element, and the third data packet forwarding rule is the rule corresponding to the data packets from the remote user plane network element forwarded by the source offloading user plane network element to the target offloading user plane network element; or, the third data packet detection rule is the rule corresponding to the data packets from the source user plane network element detected by the source offloading user plane network element, and the third data packet forwarding rule is the rule corresponding to the data packets from the source user plane network element forwarded by the source offloading user plane network element to the target offloading user plane network element.

[0031] If the user plane network element is the target offloading user plane network element, the third packet detection rule is the rule corresponding to the data packets from the source offloading user plane network element detected by the target offloading user plane network element, and the third packet forwarding rule is the rule corresponding to the data packets from the source offloading user plane network element forwarded by the target offloading user plane network element to the target access network device. That is, either the source or target offloading user plane network element can receive a third packet forwarding control protocol request message from the intermediate session management network element. This message includes the third packet detection rule and the third packet forwarding rule, enabling either the source or target offloading user plane network element to detect data packets according to the third packet detection rule and forward data packets according to the third packet forwarding rule. This avoids the loss of downlink data packets at the terminal device and improves the reliability of data packet transmission.

[0032] Optionally, if the user plane network element is the target offloading user plane network element, the third packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element to the fourth packet detection rule according to the seventh instruction information. The third packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target access network device to the fourth packet forwarding rule according to the seventh instruction information.

[0033] If the user plane network element is the source offloading user plane network element, the third packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the fourth packet detection rule according to the seventh instruction information. The third packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the target offloading user plane network element and the Internet Protocol address of the target offloading user plane network element to the fourth packet forwarding rule according to the seventh instruction information.

[0034] The seventh indication information is used to indicate one or more of the following: the fourth packet detection rule is the rule corresponding to the detection of packets by the source or target user plane network element; the fourth packet forwarding rule is the rule corresponding to the forwarding of packets by the source or target user plane network element. It is understandable that, since the third packet detection rule also includes the tunnel endpoint identifier and Internet Protocol (IP) address of the target user plane network element, and the third packet forwarding rule also includes the tunnel endpoint identifier and IP address of the target access network device, the target user plane network element can receive and detect packets based on the tunnel endpoint identifier and IP address of the target user plane network element, and establish a tunnel with the target access network device based on the tunnel endpoint identifier and IP address of the target access network device. This allows packets to be transmitted through the tunnel, avoiding the loss of downlink packets from the terminal device. Similarly, since the third packet detection rule also includes the tunnel endpoint identifier and Internet Protocol address of the source offloading user plane network element to receive and detect packets, and the third packet forwarding rule also includes the tunnel endpoint identifier and Internet Protocol address of the target offloading user plane network element, the source offloading user plane network element can receive and detect packets based on the tunnel endpoint identifier and Internet Protocol address of the source offloading user plane network element, and establish a tunnel with the target offloading user plane network element based on the tunnel endpoint identifier and Internet Protocol address of the target offloading user plane network element. This allows packets to be transmitted through the tunnel, avoiding the loss of downlink packets from the terminal device.

[0035] Sixthly, a method for transmitting indication information is provided. The method includes: an intermediate session management network element sending first indication information to a session management network element, the first indication information indicating that the intermediate session management network element has inserted a target user plane network element and a target user plane network element, and has deleted a source user plane network element and a source user plane network element. The session management network element sends second indication information to the intermediate session management network element according to the first indication information, the second indication information indicating that the target user plane network element buffers uplink data packets. The target user plane network element receives third indication information from the intermediate session management network element, the third indication information being sent by the intermediate session management network element according to the second indication information, the third indication information indicating that the target user plane network element buffers uplink data packets.

[0036] The session management network element sends a fourth instruction message to the intermediate session management network element. This fourth instruction message instructs the target user plane network element to forward the uplink data packet. This fourth instruction message is sent by the session management network element after it learns that the target application network element has completed the handover. Based on the fourth instruction message, the intermediate session management network element sends a fifth instruction message to the target user plane network element. This fifth instruction message instructs the target user plane network element to forward the uplink data packet.

[0037] As can be seen, in the above technical solution, because the target user plane network element does not forward uplink data packets before the target application network element completes the handover, but instead buffers the uplink data packets before the target application network element completes the handover, the uplink data packets are not forwarded, thus avoiding the loss of uplink data packets. Furthermore, because the target user plane network element only forwards the uplink data packets after the target application network element completes the handover, the uplink data packets can be forwarded to the target application network element, improving the reliability of data packet transmission.

[0038] Optionally, the method further includes: the intermediate session management network element sending a first data packet forwarding control protocol request message to the user plane network element, wherein the first data packet forwarding control protocol request message includes a first data packet detection rule and a first data packet forwarding rule.

[0039] If the user plane network element is the source offloading user plane network element, the first data packet detection rule is the rule corresponding to the data packet from the target offloading user plane network element detected by the source offloading user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packet from the target offloading user plane network element forwarded by the source offloading user plane network element to the source user plane network element.

[0040] If the user plane network element is the target offloading user plane network element, the first data packet detection rule is the rule corresponding to the data packets from the target access network device detected by the target offloading user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packets from the target access network device forwarded by the target offloading user plane network element to the source offloading user plane network element.

[0041] As can be seen, in the above technical solution, the intermediate session management network element can send a first data packet forwarding control protocol request message to the source offloading user plane network element or the target offloading user plane network element. The first data packet forwarding control protocol request message includes a first data packet detection rule and a first data packet forwarding rule, so that the source offloading user plane network element or the target offloading user plane network element detects data packets according to the first data packet detection rule and forwards data packets according to the first data packet forwarding rule, thereby avoiding the loss of uplink data packets of the terminal device and improving the reliability of data packet transmission.

[0042] Optionally, the method further includes: a second data packet detection rule, a second data packet forwarding rule, and a sixth indication information from the session management network element to the intermediate session management network element. The sixth indication information indicates one or more of the following: the second data packet detection rule is the rule corresponding to the data packet detected by the source or target user plane network element; the second data packet forwarding rule is the rule corresponding to the data packet forwarded by the source or target user plane network element.

[0043] As can be seen, in the above technical solution, the session management network element can send the second data packet detection rule, the second data packet forwarding rule, and the sixth indication information to the intermediate session management network element, so that the intermediate session management network element can know one or more of the following: the second data packet detection rule is the rule corresponding to the data packet detected by the source diversion user plane network element or the target diversion user plane network element; the second data packet forwarding rule is the rule corresponding to the data packet forwarded by the source diversion user plane network element or the target diversion user plane network element.

[0044] Optionally, if the user plane network element is the target offloading user plane network element, the first packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the target offloading user plane network element and the Internet Protocol address of the target offloading user plane network element to the second packet detection rule according to the sixth instruction information. The first packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the second packet forwarding rule according to the sixth instruction information.

[0045] If the user plane network element is a source-splitting user plane network element, the first packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source-splitting user plane network element and the Internet Protocol address of the source-splitting user plane network element to the second packet detection rule according to the sixth instruction information. The first packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source user plane network element and the Internet Protocol address of the source user plane network element to the second packet forwarding rule according to the sixth instruction information.

[0046] As can be seen, in the above technical solution, since the first data packet detection rule also includes the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element, and the first data packet forwarding rule also includes the tunnel endpoint identifier and the Internet Protocol address of the source offloading user plane network element, the target offloading user plane network element can receive and detect data packets based on the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element, and establish a tunnel with the source offloading user plane network element based on the tunnel endpoint identifier and the Internet Protocol address of the source offloading user plane network element, so that data packets can be transmitted through the tunnel, avoiding the loss of downlink data packets of the terminal device. Similarly, since the first data packet detection rule also includes the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element, and the first data packet forwarding rule also includes the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element, the source user plane network element can receive and detect data packets based on the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element. It can also establish a tunnel with the source user plane network element based on the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element, so that data packets can be transmitted through the tunnel, avoiding the loss of downlink data packets of the terminal device.

[0047] In a seventh aspect, a message transmission method is provided, the method comprising: an intermediate session management network element sending a third data packet forwarding control protocol request message to a user plane network element, the third data packet forwarding control protocol request message including a third data packet detection rule and a third data packet forwarding rule.

[0048] If the user plane network element is a source offloading user plane network element, the third data packet detection rule is the rule corresponding to the data packets from the remote user plane network element detected by the source offloading user plane network element, and the third data packet forwarding rule is the rule corresponding to the data packets from the remote user plane network element forwarded by the source offloading user plane network element to the target offloading user plane network element; or, the third data packet detection rule is the rule corresponding to the data packets from the source user plane network element detected by the source offloading user plane network element, and the third data packet forwarding rule is the rule corresponding to the data packets from the source user plane network element forwarded by the source offloading user plane network element to the target offloading user plane network element.

[0049] If the user plane network element is the target offloading user plane network element, the third data packet detection rule is the rule corresponding to the data packet from the source offloading user plane network element detected by the target offloading user plane network element, and the third data packet forwarding rule is the rule corresponding to the data packet from the source offloading user plane network element forwarded by the target offloading user plane network element to the target access network device.

[0050] As can be seen, in the above technical solution, the intermediate session management network element can send a third data packet forwarding control protocol request message to the source diversion user plane network element or the target diversion user plane network element. The third data packet forwarding control protocol request message includes the third data packet detection rule and the third data packet forwarding rule, so that the source diversion user plane network element or the target diversion user plane network element detects data packets according to the third data packet detection rule and forwards data packets according to the third data packet forwarding rule, thereby avoiding the loss of downlink data packets of the terminal device and improving the reliability of data packet transmission.

[0051] Optionally, the method further includes: the session management network element sending a fourth data packet detection rule, a fourth data packet forwarding rule, and seventh indication information to the intermediate session management network element. The seventh indication information indicates one or more of the following: the fourth data packet detection rule is the rule corresponding to the data packet detected by the source or target user plane network element; the fourth data packet forwarding rule is the rule corresponding to the data packet forwarded by the source or target user plane network element.

[0052] As can be seen, in the above technical solution, the session management network element can send the fourth data packet detection rule, the fourth data packet forwarding rule, and the seventh indication information to the intermediate session management network element, so that the intermediate session management network element can know one or more of the following: the fourth data packet detection rule is the rule corresponding to the data packet detected by the source diversion user plane network element or the target diversion user plane network element; the fourth data packet forwarding rule is the rule corresponding to the data packet forwarded by the source diversion user plane network element or the target diversion user plane network element.

[0053] Optionally, if the user plane network element is the target offloading user plane network element, the third packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element to the fourth packet detection rule according to the seventh instruction information. The third packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target access network device to the fourth packet forwarding rule according to the seventh instruction information.

[0054] If the user plane network element is the source offloading user plane network element, the third packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the fourth packet detection rule according to the seventh instruction information. The third packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the target offloading user plane network element and the Internet Protocol address of the target offloading user plane network element to the fourth packet forwarding rule according to the seventh instruction information.

[0055] As can be seen, in the above technical solution, since the third data packet detection rule also includes the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element, and the third data packet forwarding rule also includes the tunnel endpoint identifier and the Internet Protocol address of the target access network device, the target offloading user plane network element can receive and detect data packets based on the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element, and establish a tunnel with the target access network device based on the tunnel endpoint identifier and the Internet Protocol address of the target access network device, so that data packets can be transmitted through the tunnel, avoiding the loss of downlink data packets of the terminal device. Similarly, since the third packet detection rule also includes the tunnel endpoint identifier and Internet Protocol (IP) address of the source user plane network element, and the third packet forwarding rule also includes the tunnel endpoint identifier and IP address of the target user plane network element, the source user plane network element can receive and detect packets based on the tunnel endpoint identifier and IP address of the source user plane network element, and establish a tunnel with the target user plane network element based on the tunnel endpoint identifier and IP address of the target user plane network element. This allows packets to be transmitted through the tunnel, avoiding the loss of downlink packets from the terminal device.

[0056] Eighthly, an intermediate session management network element is provided, the intermediate session management network element including a transceiver module, the transceiver module being used to send first indication information to the session management network element, the first indication information being used to indicate that the intermediate session management network element has inserted a target off-line user plane network element and a target user plane network element, and has deleted a source off-line user plane network element and a source user plane network element.

[0057] The transceiver module is used to receive second indication information from the session management network element. The second indication information is used to instruct the target user plane network element to buffer uplink data packets.

[0058] The transceiver module is used to send third indication information to the target user plane network element according to the second indication information. The third indication information is used to instruct the target user plane network element to buffer uplink data packets.

[0059] The transceiver module is used to receive fourth indication information from the session management network element. The fourth indication information is used to instruct the target user plane network element to forward the uplink data packet.

[0060] The transceiver module is used to send fifth indication information to the target user plane network element according to the fourth indication information. The fifth indication information is used to instruct the target user plane network element to forward the uplink data packet.

[0061] Optionally, the transceiver module is also used to send a first data packet forwarding control protocol request message to the user plane network element. The first data packet forwarding control protocol request message includes a first data packet detection rule and a first data packet forwarding rule.

[0062] If the user plane network element is the source offloading user plane network element, the first data packet detection rule is the rule corresponding to the data packet from the target offloading user plane network element detected by the source offloading user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packet from the target offloading user plane network element forwarded by the source offloading user plane network element to the source user plane network element.

[0063] If the user plane network element is the target offloading user plane network element, the first data packet detection rule is the rule corresponding to the data packets from the target access network device detected by the target offloading user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packets from the target access network device forwarded by the target offloading user plane network element to the source offloading user plane network element.

[0064] Optionally, the transceiver module is also used to receive the second data packet detection rule, the second data packet forwarding rule, and the sixth indication information from the session management network element. The sixth indication information indicates one or more of the following: the second data packet detection rule is the rule corresponding to the data packet detected by the source or destination user plane network element; the second data packet forwarding rule is the rule corresponding to the data packet forwarded by the source or destination user plane network element.

[0065] Optionally, if the user plane network element is the target offloading user plane network element, the first packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the target offloading user plane network element and the Internet Protocol address of the target offloading user plane network element to the second packet detection rule according to the sixth instruction information. The first packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the second packet forwarding rule according to the sixth instruction information.

[0066] If the user plane network element is a source-splitting user plane network element, the first packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source-splitting user plane network element and the Internet Protocol address of the source-splitting user plane network element to the second packet detection rule according to the sixth instruction information. The first packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source user plane network element and the Internet Protocol address of the source user plane network element to the second packet forwarding rule according to the sixth instruction information.

[0067] Ninth aspect, an intermediate session management network element is provided, the intermediate session management network element includes a transceiver module, the transceiver module is used to send a third data packet forwarding control protocol request message to a user plane network element, the third data packet forwarding control protocol request message includes a third data packet detection rule and a third data packet forwarding rule.

[0068] If the user plane network element is a source offloading user plane network element, the third data packet detection rule is the rule corresponding to the data packets from the remote user plane network element detected by the source offloading user plane network element, and the third data packet forwarding rule is the rule corresponding to the data packets from the remote user plane network element forwarded by the source offloading user plane network element to the target offloading user plane network element; or, the third data packet detection rule is the rule corresponding to the data packets from the source user plane network element detected by the source offloading user plane network element, and the third data packet forwarding rule is the rule corresponding to the data packets from the source user plane network element forwarded by the source offloading user plane network element to the target offloading user plane network element.

[0069] If the user plane network element is the target offloading user plane network element, the third data packet detection rule is the rule corresponding to the data packet from the source offloading user plane network element detected by the target offloading user plane network element, and the third data packet forwarding rule is the rule corresponding to the data packet from the source offloading user plane network element forwarded by the target offloading user plane network element to the target access network device.

[0070] Optionally, the transceiver module is also used to receive the fourth data packet detection rule, the fourth data packet forwarding rule, and the seventh indication information from the session management network element. The seventh indication information indicates one or more of the following: the fourth data packet detection rule is the rule corresponding to the data packet detected by the source or destination user plane network element; the fourth data packet forwarding rule is the rule corresponding to the data packet forwarded by the source or destination user plane network element.

[0071] Optionally, if the user plane network element is the target offloading user plane network element, the third packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network to the fourth packet detection rule according to the seventh instruction information. The third packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target access network device to the fourth packet forwarding rule according to the seventh instruction information.

[0072] If the user plane network element is the source offloading user plane network element, the third packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the fourth packet detection rule according to the seventh instruction information. The third packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the target offloading user plane network element and the Internet Protocol address of the target offloading user plane network element to the fourth packet forwarding rule according to the seventh instruction information.

[0073] In a tenth aspect, a session management network element is provided, comprising a transceiver module. The transceiver module is configured to receive first indication information from an intermediate session management network element. The first indication information indicates that the intermediate session management network element has inserted a target user plane network element and a target user plane network element, and has deleted a source user plane network element and a source user plane network element. The transceiver module is configured to send second indication information to the intermediate session management network element based on the first indication information. The second indication information indicates that the target user plane network element buffers uplink data packets. The transceiver module is configured to send fourth indication information to the intermediate session management network element. The fourth indication information indicates that the target user plane network element forwards uplink data packets. The fourth indication information is sent by the session management network element after it learns that the target application network element has completed the handover.

[0074] Optionally, the transceiver module is also used to send the second data packet detection rule, the second data packet forwarding rule, and the sixth indication information to the intermediate session management network element. The sixth indication information indicates one or more of the following: the second data packet detection rule is the rule corresponding to the data packet detected by the source or destination user plane network element; the second data packet forwarding rule is the rule corresponding to the data packet forwarded by the source or destination user plane network element.

[0075] Eleventhly, a user plane network element is provided, which includes a transceiver module. The transceiver module is used to receive a first data packet forwarding control protocol request message from an intermediate session management network element. The first data packet forwarding control protocol request message includes a first data packet detection rule and a first data packet forwarding rule.

[0076] If the user plane network element is the source offloading user plane network element, the first data packet detection rule is the rule corresponding to the data packet from the target offloading user plane network element detected by the source offloading user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packet from the target offloading user plane network element forwarded by the source offloading user plane network element to the source user plane network element.

[0077] If the user plane network element is the target offloading user plane network element, the first data packet detection rule is the rule corresponding to the data packets from the target access network device detected by the target offloading user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packets from the target access network device forwarded by the target offloading user plane network element to the source offloading user plane network element.

[0078] Optionally, the transceiver module is also used to receive a first data packet forwarding control protocol request message from the intermediate session management network element. The first data packet forwarding control protocol request message includes a first data packet detection rule and a first data packet forwarding rule.

[0079] If the user plane network element is the source offloading user plane network element, the first data packet detection rule is the rule corresponding to the data packet from the target offloading user plane network element detected by the source offloading user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packet from the target offloading user plane network element forwarded by the source offloading user plane network element to the source user plane network element.

[0080] If the user plane network element is the target offloading user plane network element, the first data packet detection rule is the rule corresponding to the data packets from the target access network device detected by the target offloading user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packets from the target access network device forwarded by the target offloading user plane network element to the source offloading user plane network element.

[0081] Optionally, if the user plane network element is the target offloading user plane network element, the first packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the target offloading user plane network element and the Internet Protocol address of the target offloading user plane network element to the second packet detection rule according to the sixth instruction information. The first packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the second packet forwarding rule according to the sixth instruction information.

[0082] If the user plane network element is a source-splitting user plane network element, the first packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source-splitting user plane network element and the Internet Protocol address of the source-splitting user plane network element to the second packet detection rule according to the sixth instruction information. The first packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source user plane network element and the Internet Protocol address of the source user plane network element to the second packet forwarding rule according to the sixth instruction information.

[0083] The sixth indication information is used to indicate one or more of the following: the second data packet detection rule is the rule corresponding to the detection of data packets by the source diversion user plane network element or the target diversion user plane network element; the second data packet forwarding rule is the rule corresponding to the forwarding of data packets by the source diversion user plane network element or the target diversion user plane network element.

[0084] In a twelfth aspect, a user plane network element is provided, which includes a transceiver module for receiving a third data packet forwarding control protocol request message from an intermediate session management network element. The third data packet forwarding control protocol request message includes a third data packet detection rule and a third data packet forwarding rule.

[0085] If the user plane network element is a source offloading user plane network element, the third data packet detection rule is the rule corresponding to the data packets from the remote user plane network element detected by the source offloading user plane network element, and the third data packet forwarding rule is the rule corresponding to the data packets from the remote user plane network element forwarded by the source offloading user plane network element to the target offloading user plane network element; or, the third data packet detection rule is the rule corresponding to the data packets from the source user plane network element detected by the source offloading user plane network element, and the third data packet forwarding rule is the rule corresponding to the data packets from the source user plane network element forwarded by the source offloading user plane network element to the target offloading user plane network element.

[0086] If the user plane network element is the target offloading user plane network element, the third data packet detection rule is the rule corresponding to the data packet from the source offloading user plane network element detected by the target offloading user plane network element, and the third data packet forwarding rule is the rule corresponding to the data packet from the source offloading user plane network element forwarded by the target offloading user plane network element to the target access network device.

[0087] Optionally, if the user plane network element is the target offloading user plane network element, the third packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element to the fourth packet detection rule according to the seventh instruction information. The third packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target access network device to the fourth packet forwarding rule according to the seventh instruction information.

[0088] If the user plane network element is the source offloading user plane network element, the third packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the fourth packet detection rule according to the seventh instruction information. The third packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the target offloading user plane network element and the Internet Protocol address of the target offloading user plane network element to the fourth packet forwarding rule according to the seventh instruction information.

[0089] The seventh indication information is used to indicate one or more of the following: the fourth data packet detection rule is the rule corresponding to the detection of data packets by the source diversion user plane network element or the target diversion user plane network element; the fourth data packet forwarding rule is the rule corresponding to the forwarding of data packets by the source diversion user plane network element or the target diversion user plane network element.

[0090] In a thirteenth aspect, a communication device is provided, comprising a processor, a memory, an input interface, and an output interface, wherein the input interface is used to receive information from other communication devices outside the communication device, the output interface is used to output information to other communication devices outside the communication device, and the processor invokes a computer program stored in the memory to implement the method of any one of the first, second, third, fourth, or fifth aspects.

[0091] In one possible design, the communication device may be a chip or a device containing a chip that implements any one of the methods of the first, second, third, fourth, or fifth aspects.

[0092] Fourteenthly, a computer-readable storage medium is provided, in which a computer program is stored, which, when executed, implements the method of any one of the first, second, third, fourth, or fifth aspects.

[0093] In a fifteenth aspect, a chip is provided, the chip including at least one processor and an interface, the processor being configured to read and execute instructions stored in a memory, wherein when the instructions are executed, the chip causes the chip to perform a method as described in any one of the first, second, third, fourth, or fifth aspects.

[0094] In a sixteenth aspect, a computer program product containing instructions is provided, which, when executed on a computer, causes the method of any one of the first, second, third, fourth, or fifth aspects to be performed.

[0095] In a seventeenth aspect, a communication system is provided, comprising one or more of the following: an intermediate session management network element, a session management network element, and a user plane network element. The user plane network element comprises one or more of the following: a target user plane network element, a source offloading user plane network element, and a target offloading user plane network element.

[0096] Eighteenth aspect, a communication system is provided, the communication system including an intermediate session management network element, a session management network element and a user plane network element, wherein the intermediate session management network element is used to perform the method described in any one of the first aspects, the session management network element is used to perform the method described in any one of the third aspects, and the user plane network element is used to perform the method described in any one of the fourth aspects.

[0097] In a nineteenth aspect, a communication system is provided, the communication system comprising an intermediate session management network element and a user plane network element, the intermediate session management network element being used to perform the method described in the second aspect, and the user plane network element being used to perform the method described in any one of the fifth aspects. Attached Figure Description

[0098] The accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0099] in:

[0100] Figure 1 The basic architecture of the communication system provided in the embodiments of this application;

[0101] Figure 2A This is a schematic diagram of a 5G network architecture based on a service-oriented architecture.

[0102] Figure 2B This is a schematic diagram of a 5G network architecture based on a point-to-point interface.

[0103] Figure 3 The diagram shown is a hardware structure schematic of a communication device applicable to the embodiments of this application;

[0104] Figure 4 A flowchart illustrating a method for transmitting indication information provided in an embodiment of this application;

[0105] Figure 5 A flowchart illustrating a message transmission method provided in an embodiment of this application;

[0106] Figure 6A A flowchart illustrating another message transmission method provided in an embodiment of this application;

[0107] Figure 6B A flowchart illustrating another message transmission method provided in an embodiment of this application;

[0108] Figure 6C A flowchart illustrating another message transmission method provided in an embodiment of this application;

[0109] Figure 7A A flowchart illustrating another message transmission method provided in an embodiment of this application;

[0110] Figure 7B A flowchart illustrating another message transmission method provided in an embodiment of this application;

[0111] Figure 7C A flowchart illustrating another message transmission method provided in an embodiment of this application;

[0112] Figure 8 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application. Detailed Implementation

[0113] The technical solutions in the embodiments of this application will be described below with reference to the accompanying drawings. The terms "system" and "network" in the embodiments of this application can be used interchangeably. Unless otherwise stated, " / " indicates that the objects before and after are in an "or" relationship; for example, A / B can represent A or B. "And / or" in this application is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone, where A and B can be singular or plural. Furthermore, in the description of this application, unless otherwise stated, "multiple" refers to two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be one or multiple. Furthermore, to facilitate a clear description of the technical solutions in the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish between network elements and similar items with essentially the same function. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" are not necessarily different.

[0114] References to "one embodiment" or "some embodiments" in the embodiments described in this application mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0115] The following detailed embodiments further illustrate the objectives, technical solutions, and beneficial effects of this application. It should be understood that the following are merely specific embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made based on the technical solutions of this application should be included within the scope of protection of this application.

[0116] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0117] It should be understood that the technical solutions of the embodiments of this application can be applied to fifth-generation mobile communication technology (5G), etc. The technical solutions of the embodiments of this application can also be applied to other future communication systems, such as 6G communication systems. In future communication systems, the functions may remain the same, but the names may change.

[0118] The basic architecture of the communication system provided in the embodiments of this application is described below. See also Figure 1 , Figure 1 The basic architecture of the communication system provided in the embodiments of this application. For example... Figure 1 As shown, the communication system may include one or more of the following network elements: intermediate session management network element, session management network element, user plane network element, access network equipment, terminal equipment, mobility management network element, application network element, and a data network (DN) connecting to the operator's network. The terminal equipment can send data packets to the data network and receive data packets from the data network through the access network equipment and user plane network elements. It is understood that in this application, the data packets can be service data. Furthermore, Figure 1 This is merely an illustrative diagram and does not constitute a limitation on the applicable scenarios of the technical solutions provided in this application.

[0119] The intermediate session management network element can be selected from user plane network elements providing offloading functions and local user plane network elements. Understandably, during the terminal device movement process, such as Xn handover, N2 handover, service requests, and tracking area updates, the intermediate session management network element can select user plane network elements or local user plane network elements based on the location of the terminal device. In 5G communication systems, the intermediate session management network element can be an intermediate session management function (I-SMF) network element. In future communication systems (such as 6G communication systems), the intermediate session management network element can still be an I-SMF network element, or it can have other names; this application is not limited to these.

[0120] The session management network element is primarily used for session management in mobile networks, such as session establishment, modification, and release. Specific functions include allocating Internet Protocol (IP) addresses to terminal devices and selecting remote user plane network elements that provide packet forwarding capabilities. In 5G communication systems, the session management network element can be a session management function (SMF) network element. In future communication systems (such as 6G communication systems), the session management network element may still be an SMF network element, or it may have other names; this application does not limit this.

[0121] User plane network elements are primarily used for processing user packets, such as forwarding, billing, and lawful interception. These can be remote or local user plane network elements. Both remote and local user plane network elements can be Protocol Data Unit (PDU) session anchors (PSAs). Their deployment locations differ; for example, local user plane network elements are selected and forwarded by intermediate session management network elements, while remote user plane network elements are selected and forwarded by session management network elements. Additionally, user plane network elements can also be used for packet offloading, functioning as offloading user plane network elements, which can be uplink offloading devices or offloading points. In 5G communication systems, user plane network elements can be user plane function (UPF) network elements. In future communication systems (such as 6G communication systems), user plane network elements may remain UPF network elements or have other names; this application does not limit this. It is understood that in this application, both the source user plane network element and the target user plane network element are local user plane network elements, and both the source off-line user plane network element and the target off-line user plane network element are off-line user plane network elements. For example, the source user plane network element can be a local user plane network element determined by the intermediate session management network element based on the terminal device's position before cell reselection, the target user plane network element can be a local user plane network element determined by the intermediate session management network element based on the terminal device's position after cell reselection, the source offloading user plane network element can be an offloading user plane network element determined by the intermediate session management network element based on the terminal device's position before cell reselection, and the target offloading user plane network element can be an offloading user plane network element determined by the intermediate session management network element based on the terminal device's position after cell reselection; or, the source user plane network element can be a local user plane network element determined by the intermediate session management network element based on the terminal device's position before cell handover, the target user plane network element can be a local user plane network element determined by the intermediate session management network element based on the terminal device's position after cell handover, the source offloading user plane network element can be an offloading user plane network element determined by the intermediate session management network element based on the terminal device's position before cell handover, and the target offloading user plane network element can be an offloading user plane network element determined by the intermediate session management network element based on the terminal device's position after cell handover.

[0122] Access network equipment is a network-side entity used to transmit or receive signals, or both. Access network equipment can be devices deployed in a radio access network (RAN) to provide wireless communication functions for terminal devices. Examples include transmission reception points (TRPs), base stations, and various types of control nodes, such as network controllers, radio controllers, and radio controllers in cloud radio access network (CRAN) scenarios. Specifically, access network equipment can be various types of macro base stations, micro base stations (also called small stations), relay stations, access points (APs), radio network controllers (RNCs), node Bs (NBs), base station controllers (BSCs), base transceiver stations (BTSs), home-evolved node Bs (e.g., home-evolved node Bs or home node Bs (HNBs), baseband units (BBUs), transmitting points (TPs), mobile switching centers, etc., or it can be the antenna panel of a base station. A control node can connect to multiple base stations and configure resources for multiple terminals covered by these base stations. In systems employing different wireless access technologies, the names of devices with base station functions may vary. For example, it could be a gNB in ​​5G, a network-side device in a 5G or later network, or an access network device in a future public land mobile network (PLMN). This application does not limit the specific name of the access network device. Furthermore, the access network device may also include a central unit (CU) and a distributed unit (DU) integrated on the gNB. It is understood that in this application, the access network device can be a source access network device or a target access network device. For example, the source access network device is the access network device before cell reselection for the terminal device, and the target access network device is the access network device after cell reselection for the terminal device.

[0123] In this context, a terminal device is an entity on the user side used to receive signals, or transmit signals, or both. The terminal device is used to provide users with one or more of the following: voice services and data connectivity services. The terminal device can be a device that includes wireless transceiver capabilities and can cooperate with access network equipment to provide communication services to users. Specifically, a terminal device can refer to user equipment (UE), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, terminal, wireless communication equipment, user agent, or user device. Terminal devices can also include drones, Internet of Things (IoT) devices, WLAN stations (STs), cellular phones, smartphones, cordless phones, wireless data cards, tablets, Session Initiation Protocol (SIP) phones, Wireless Local Loop (WLL) stations, personal digital assistant (PDA) devices, laptop computers, machine-type communication (MTC) terminals, handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, in-vehicle devices, wearable devices (also known as wearable smart devices), virtual reality (VR) terminals, augmented reality (AR) terminals, wireless terminals in industrial control, wireless terminals in self-driving vehicles, wireless terminals in remote medical care, wireless terminals in smart grids, wireless terminals in transportation safety, and smart city applications. Wireless terminals in cities, wireless terminals in smart homes, etc. Terminal devices can also be device-to-device (D2D) devices, such as electricity meters, water meters, etc. Terminal devices can also be terminals in 5G systems or terminals in next-generation communication systems; this application does not limit this.

[0124] The mobility management network element (AMF) has one or more of the following functions: registration, security authentication, and key negotiation for terminal devices in the mobile network; maintenance of Non-Access Stratum (NAS) connections; mobility management; and routing signaling between terminal devices and other network elements. For example, routing session management (SM) messages between terminal devices and session management network elements. In 5G communication, Namf is a service-based interface provided by the mobility management network element, through which the mobility management network element can communicate with other network functions. It is understood that this application does not limit the name of the mobility management network element. For example, the mobility management network element can be called an AMF network element.

[0125] Application network elements can provide various application service data to the control plane functions of the operator's communication network, obtain network data and control information from the control plane functions of the communication network, or provide various application service data to terminal devices. In 5G communication systems, application network elements can be application function (AF) network elements. In future communication systems (such as 6G communication systems), application functions can still be AF network elements, or they can have other names; this application is not limited to these.

[0126] Data networks are primarily used to provide data transmission services for terminal devices. Data networks can be private networks, such as local area networks (LANs), public data networks (PDNs), such as the Internet, or dedicated networks jointly deployed by operators, such as configured IP multimedia core network subsystems (IMS) services.

[0127] It should be noted that, in this application, the intermediate session management network element can be deployed separately or integrated into the session management network element; this application makes no restriction. Furthermore, the source user plane network element and the source user plane network element can be deployed together or separately; when deployed separately, their service areas can be different. Similarly, the target user plane network element and the target user plane network element can be deployed together or separately; when deployed separately, their service areas can be different; this application makes no restriction.

[0128] The following uses a 5G communication system as an example to illustrate a specific possible network architecture applicable to the embodiments of this application. Figure 2A This is a schematic diagram of a 5G network architecture based on a service-oriented architecture. Figure 2B The 5G network architecture shown may include data networks and carrier networks. The functions of some of these network elements are briefly described below.

[0129] The operator network may include one or more of the following network elements: Authentication Server Function (AUSF) network element, Network Exposure Function (NEF) network element, Policy Control Function (PCF) network element, Unified Data Management (UDM) network element, Unified Data Repository (UDR) network element, Network Repository Function (NRF) network element, AF network element, Access and Mobility Management Function (AMF) network element, SMF network element, RAN equipment, UPF network element, and Network Slice Selection Function (NSSF) network element. Figure 2A or Figure 2B (Not shown in the image), etc. In the above-mentioned operator networks, network elements or equipment other than radio access network equipment can be referred to as core network elements or core network equipment.

[0130] Wireless access network equipment can be a base station, an evolved NodeB (eNodeB), a TRP, a next-generation NodeB (gNB) in a 5G mobile communication system, a next-generation base station in a 6G mobile communication system, a base station in a future mobile communication system, or an access node in a wireless fidelity (WiFi) system; it can also be a module or unit that performs some of the functions of a base station, for example, a CU or a distributed unit (DU). Wireless access network equipment can be a macro base station, a micro base station, an indoor station, a relay node, or a donor node, etc. The embodiments of this application do not limit the specific technology or specific equipment form used in the wireless access network equipment.

[0131] The terminal communicating with the RAN can also be called a terminal device, UE, mobile station, mobile terminal, etc. Terminals can be widely used in various scenarios, such as device-to-device (D2D), vehicle-to-everything (V2X) communication, MTC, Internet of Things (IoT), virtual reality, augmented reality, industrial control, autonomous driving, telemedicine, smart grids, smart furniture, smart offices, smart wearables, smart transportation, smart cities, etc. Terminals can be mobile phones, tablets, computers with wireless transceiver capabilities, wearable devices, vehicles, drones, helicopters, airplanes, ships, robots, robotic arms, smart home devices, etc. The embodiments of this application do not limit the specific technology or device form used in the terminal.

[0132] Base stations and terminals can be fixed or mobile. They can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on water; and they can be deployed in the air on aircraft, balloons, and artificial satellites. The embodiments of this application do not limit the application scenarios of base stations and terminals.

[0133] The AMF (Automatic Mobility Management) network element performs functions such as mobility management and access authentication / authorization. In addition, it is responsible for transmitting user policies between the terminal and the PCF (Programmable Default Function).

[0134] The SMF network element performs functions such as session management, execution of control policies issued by the PCF, selection of the UPF, and allocation of IP addresses for terminals.

[0135] UPF network elements, as the interface between the network and the data network, perform functions such as user plane data forwarding, session / flow-based billing statistics, and bandwidth limiting.

[0136] UDM network elements perform functions such as managing contracted data and authorizing user access.

[0137] UDR performs data storage and retrieval functions for types of data such as contract data, policy data, and application data.

[0138] NEF network elements are used to support the opening of capabilities and events.

[0139] AF (Application Provider) elements convey application-side requests to the network side, such as QoS requirements or user state event subscriptions. AFs can be third-party functional entities or application services deployed by operators, such as IMS voice call services.

[0140] The PCF network element is responsible for policy control functions such as billing at the session and service flow levels, QoS bandwidth guarantee and mobility management, and terminal policy decision-making.

[0141] NRF network elements can be used to provide network element discovery functionality, providing network element information corresponding to the network element type based on requests from other network elements. NRF also provides network element management services, such as network element registration, updates, deregistration, and network element status subscription and push.

[0142] The AUSF network element is responsible for authenticating users to determine whether to allow users or devices to access the network.

[0143] NSSF network elements are used to select network slices and count users within a network slice.

[0144] A Domain Provider (DN) is a network located outside the carrier's network. A carrier's network can connect to multiple DNs, and various services can be deployed on a DN, providing data and / or voice services to terminals. For example, a DN might be the private network of a smart factory. Sensors installed in the workshop can act as terminals, and a control server for these sensors is deployed within the DN. The control server provides services to the sensors. Sensors can communicate with the control server, receive instructions from it, and transmit the collected sensor data back to the control server accordingly. Another example is a DN serving as an internal office network for a company. Employees' mobile phones or computers can act as terminals, accessing information and data resources on the company's internal office network.

[0145] Figure 2A Nausf, Nnef, Npcf, Nudm, Naf, Namf, and Nsmf are the service interfaces provided by AUSF, NEF, PCF, UDM, AF, AMF, and SMF, respectively, used to invoke the corresponding service operations. N1, N2, N3, N4, and N6 are interface sequence numbers. The meanings of these interface sequence numbers can be found in the definitions in the 3rd Generation Partnership Project (3GPP) standard protocol, and are not limited here.

[0146] Figure 2B This is a schematic diagram of a 5G network architecture based on a point-to-point interface. For a description of the functions of the network elements, please refer to [reference needed]. Figure 2A The functions of the corresponding network elements will not be described in detail here. Figure 2B and Figure 2A The main difference is: Figure 2A The interfaces between the various control plane network elements are service-oriented interfaces. Figure 2B The interfaces between the various control plane network elements are point-to-point interfaces.

[0147] exist Figure 2B In the architecture shown, the interface names and functions between the various network elements are as follows:

[0148] 1) N1: The interface between AMF and the terminal, which can be used to transmit QoS control rules to the terminal.

[0149] 2) N2: The interface between AMF and RAN, which can be used to transmit radio bearer control information from the core network side to the RAN.

[0150] 3) N3: The interface between RAN and UPF, mainly used to transmit uplink and downlink user plane data between RAN and UPF.

[0151] 4) N4: The interface between SMF and UPF, which can be used to transmit information between the control plane and the user plane, including the distribution of forwarding rules, QoS control rules, traffic statistics rules, etc. from the control plane to the user plane, as well as the reporting of information from the user plane.

[0152] 5) N5: The interface between AF and PCF, which can be used for application service request distribution and network event reporting.

[0153] 6) N6: The interface between UPF and DN, used to transmit uplink and downlink user data streams between UPF and DN.

[0154] 7) N7: The interface between PCF and SMF, which can be used to issue protocol data unit (PDU) session granularity and business data flow granularity control strategies.

[0155] 8) N8: The interface between AMF and UDM, which can be used by AMF to obtain access and mobility management related subscription data and authentication data from UDM, as well as by AMF to register terminal current mobility management related information with UDM.

[0156] 9) N9: User plane interface between UPFs, used to transmit uplink and downlink user data streams between UPFs.

[0157] 10) N10: The interface between SMF and UDM, which can be used by SMF to obtain session management-related subscription data from UDM, and by SMF to register terminal current session-related information with UDM.

[0158] 11) N11: The interface between SMF and AMF, which can be used to transmit PDU session tunnel information between RAN and UPF, transmit control messages sent to the terminal, and transmit radio resource control information sent to RAN, etc.

[0159] 12) N12: The interface between AMF and AUSF, which can be used by AMF to initiate the authentication process to AUSF, and can carry the user-concealed identifier (SUCI) as the subscription identifier;

[0160] 13) N13: The interface between UDM and AUSF, which can be used by AUSF to obtain the user authentication vector from UDM in order to execute the authentication process.

[0161] 14) N15: The interface between PCF and AMF, which can be used to issue terminal policies and access control related policies.

[0162] 15) N35: The interface between UDM and UDR, which can be used by UDM to obtain user subscription data information from UDR.

[0163] 16) N36: The interface between PCF and UDR, which can be used by PCF to obtain policy-related contract data and application data related information from UDR.

[0164] It is understood that the aforementioned network element or function can be a network component in a hardware device, a software function running on dedicated hardware, or a virtualized function instantiated on a platform (e.g., a cloud platform). Optionally, the aforementioned network element or function can be implemented by one device, multiple devices working together, or a functional module within a single device; this application embodiment does not specifically limit this.

[0165] The session management network element, user plane network element, and policy control network element in this application can be respectively... Figure 2A or Figure 2B The SMF, UPF, and PCF mentioned above can also refer to network elements in future communications such as 6G networks that have the functions of the aforementioned SMF, UPF, and PCF; this application does not limit this. In the embodiments of this application, SMF, UPF, and PCF are described as examples of session management network elements, user plane network elements, and policy control network elements, respectively.

[0166] It is understood that the aforementioned network elements or functions can be network components in hardware devices, software functions running on dedicated hardware, or virtualization functions instantiated on a platform (e.g., a cloud platform). These network elements or functions can be divided into one or more services; furthermore, services existing independently of network functions may also exist. In this application, instances of the aforementioned functions, instances of services included in the aforementioned functions, or instances of services existing independently of network functions can all be referred to as service instances.

[0167] Furthermore, the technical solutions provided in this application are applicable to various system architectures. The network architectures and business scenarios described in this application are for the purpose of more clearly illustrating the technical solutions of this application and do not constitute a limitation on the technical solutions provided in this application. As those skilled in the art will understand, with the evolution of network architectures and the emergence of new business scenarios, the technical solutions provided in this application are also applicable to similar technical problems.

[0168] Optional, Figure 1 Each network element (e.g., intermediate session management network element, session management network element, user plane network element, access network equipment, terminal equipment, mobility management network element, application network element, etc.) can be implemented by a single device, multiple devices working together, or a functional module within a single device. This application does not specifically limit this. It is understood that the aforementioned functions can be network elements within hardware devices, software functions running on dedicated hardware, or virtualized functions instantiated on a platform (e.g., a cloud platform).

[0169] For example, Figure 1 Each device in the system can be accessed via Figure 3 This is achieved through the communication device 300. Figure 3 The diagram shows a hardware structure of a communication device applicable to embodiments of this application. The communication device 300 includes at least one processor 301, a communication line 302, and at least one communication interface 304.

[0170] The processor 301 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits used to control the execution of the program of the present application.

[0171] Communication line 302 may include a path for transmitting information between the aforementioned components.

[0172] Communication interface 304 is any transceiver-like device (such as an antenna) used to communicate with other devices or communication networks, such as Ethernet, RAN, wireless local area networks (WLAN), etc.

[0173] Optionally, the communication device 300 further includes a memory 303. The memory 303 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or it may be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media, or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but is not limited thereto. The memory may exist independently and be connected to the processor via the communication line 302. The memory may also be integrated with the processor. The memory provided in the embodiments of this application may generally be non-volatile. The memory 303 stores computer execution instructions for implementing the scheme of this application, and the processor 301 controls the execution. The processor 301 executes the computer execution instructions stored in the memory 303 to implement the method provided in the following embodiments of this application.

[0174] Optionally, the computer execution instructions in the embodiments of this application may also be referred to as application code, and the embodiments of this application do not specifically limit this.

[0175] In one possible implementation, processor 301 may include one or more CPUs, for example... Figure 3 CPU0 and CPU1 in the CPU.

[0176] In one possible implementation, the communication device 300 may include multiple processors, such as... Figure 3 Processors 301 and 307 are described herein. Each of these processors may be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. A processor here may refer to one or more devices, circuits, and / or processing cores used to process data (e.g., computer program instructions).

[0177] In one possible implementation, the communication device 300 may further include an output device 305 and an input device 306. The output device 305 communicates with the processor 301 and can display information in various ways. For example, the output device 305 may be a liquid crystal display (LCD), a light-emitting diode (LED) display device, a cathode ray tube (CRT) display device, or a projector, etc. The input device 306 communicates with the processor 301 and can receive user input in various ways. For example, the input device 306 may be a mouse, keyboard, touchscreen device, or sensing device, etc.

[0178] The aforementioned communication device 300 can be a general-purpose device or a special-purpose device. In specific implementations, the communication device 300 can be a desktop computer, laptop computer, network server, handheld computer, mobile phone, tablet computer, wireless terminal device, embedded device, or other similar device. Figure 3 Devices with similar structures. This application does not limit the type of communication device 300 to any particular embodiment.

[0179] The technical solutions provided in the embodiments of this application are described below with reference to the accompanying drawings.

[0180] See Figure 4 , Figure 4 This is a flowchart illustrating a method for transmitting indication information provided in an embodiment of this application. Figure 4 As shown, the method includes, but is not limited to, the following steps:

[0181] 401. The intermediate session management network element sends a first indication message to the session management network element. The first indication message is used to indicate that the intermediate session management network element has inserted the target offloading user plane network element and the target user plane network element, and has deleted the source offloading user plane network element and the source user plane network element.

[0182] Correspondingly, the session management network element receives the first instruction information from the intermediate session management network element.

[0183] It should be noted that, in this application, the first instruction information is used to indicate that the intermediate session management network element has inserted the target offloading user plane network element and the target user plane network element, and has deleted the source offloading user plane network element and the source user plane network element. That is, the intermediate session management network element has selected the target offloading user plane network element and the target user plane network element based on the current location information of the terminal device, and has established packet forwarding control protocol (PFCP) sessions with the target offloading user plane network element and the target user plane network element respectively. Simultaneously, the intermediate session management network element needs to wait for instructions from the session management network element in order to delete the PFCP sessions of the terminal device with the source offloading user plane network element and the source user plane network element.

[0184] Optionally, the first indication information may be included in the first PDU session update request message, which instructs the session management network element to update the first PDU session. The first PDU session update request message may also include the tunnel endpoint identifier of the target offloaded user plane network element and the Internet Protocol address of the target offloaded user plane network element. The first PDU session update request message may be an Nsmf_PDUSession_Update request.

[0185] 402. The session management network element sends a second instruction to the intermediate session management network element according to the first instruction information. The second instruction information is used to instruct the target user plane network element to buffer the uplink data packets.

[0186] Correspondingly, the intermediate session management network element receives the second instruction information from the session management network element.

[0187] Optionally, step 402 can be understood as follows: The session management network element can learn from the first indication information that the intermediate session management network element has been inserted into the target user plane network element and the target user plane network element, that is, the session management network element can learn from the first indication information that the local user plane network element has changed. The change of the local user plane network element may lead to the switching of application network elements, that is, the change of the local user plane network element may lead to the source application network element switching to the target application network element. To avoid the target user plane network element forwarding uplink data packets before the target application network element completes the switching, the session management network element can first send the second indication information to the intermediate session management network element, so that the target user plane network element can first buffer the uplink data packets.

[0188] Optionally, the second indication information can be a value of the first field. The value of the first field can be at least one bit or an enumerated value, without restriction. The first field can be implemented in any of the following ways:

[0189] Method 1.1: The first field can be a newly added field or an existing field in the first PDU session update response message. The first PDU session update response message is used to indicate that the session management network element has successfully updated the first PDU session, and the first PDU session update response message can be an Nsmf_PDUSession_Update response.

[0190] Method 1.2: The first field can be a newly added field or an existing field in the first information. The first information is used to indicate the establishment of a PFCP session between the intermediate session management network element and the target user plane network element, and the first information can be N4 information. Optionally, the first information can be included in the first PDU session update response message.

[0191] Method 1.3: The first field can be a field in the first information element. The first information element is a forwarding action information element in the fifth packet forwarding rule, or an information element with a similar definition or function, or an information element with an extended field; there are no restrictions here. The fifth packet forwarding rule can be the rule corresponding to the forwarding of data packets from the target user plane network element to the data network by the target user plane network element. Optionally, the fifth packet forwarding rule can be included in the first information.

[0192] For example, when the value of the first field is 1, it is used to instruct the target user plane network element to cache uplink data packets; when the value of the first field is 0, it is used to instruct the target user plane network element not to cache uplink data packets or to have no meaning. Alternatively, when the value of the first field is 0, it is used to instruct the target user plane network element to cache uplink data packets; when the value of the first field is 1, it is used to instruct the target user plane network element not to cache uplink data packets or to have no meaning. No restrictions are imposed here.

[0193] Specifically, for method 1.3, the value of the first field can be the value of the cached bit in the first cell. The value of the cached bit can be the first numerical value, which can be 0, 1 or other numerical values, without any restrictions.

[0194] 403. The intermediate session management network element sends a third instruction to the target user plane network element based on the second instruction information. The third instruction information is used to instruct the target user plane network element to buffer uplink data packets.

[0195] Correspondingly, the target user plane network element receives third instruction information from the intermediate session management network element.

[0196] Optionally, for methods 1.2 and 1.3 in step 402, the second indication information and the third indication information are the same. That is, step 403 can be replaced by: the intermediate session management network element sending the second indication information to the target user plane network element, wherein the second indication information can be included in the Packet Forwarding Control Protocol Session Modification Request (PFCP) message, which is used to instruct the target user plane network element to update the PFCP session of the terminal equipment.

[0197] Optionally, for method 1.1 in step 402, the third indication information can be the value of the second field. The value of the second field can be at least one bit value or an enumerated value, without limitation. The second field can be a field in the second information element, which is a forwarding action information element in the fifth data packet forwarding rule, or an information element with a similar definition or function, or an information element with an extended field, without limitation. In other words, for method 1.1 in step 402, the intermediate session management network element can receive the fifth data packet forwarding rule from the session management network element. Therefore, the intermediate session management network element can send the fifth data packet forwarding rule to the target user plane network element according to the first indication information. The fifth data packet forwarding rule can be included in the data packet forwarding control protocol session update request message, which is used to instruct the target user plane network element to update the PFCP session of the terminal device.

[0198] The first information cell can be the same as or different from the second information cell; no restriction is imposed here.

[0199] The first field can be the same as or different from the second field; there are no restrictions here.

[0200] For example, when the value of the second field is 1, it is used to instruct the target user plane network element to cache uplink data packets; when the value of the second field is 0, it is used to instruct the target user plane network element not to cache uplink data packets or has no meaning; or, when the value of the second field is 0, it is used to instruct the target user plane network element to cache uplink data packets; when the value of the second field is 1, it is used to instruct the target user plane network element not to cache uplink data packets or has no meaning, and no restrictions are imposed here.

[0201] 404. The session management network element sends a fourth instruction message to the intermediate session management network element. The fourth instruction message is used to instruct the target user plane network element to forward the uplink data packet. The fourth instruction message is the instruction message sent by the session management network element after it learns that the target application network element has completed the handover.

[0202] Correspondingly, the intermediate session management network element receives the fourth instruction information from the session management network element.

[0203] The fourth indication information is the indication information sent by the session management network element after it learns that the target application network element has completed the handover. It can be understood as: the fourth indication information is the indication information sent by the session management network element after receiving the confirmation message from the target application network element. The confirmation message is used to indicate that the target application network element has completed the handover.

[0204] Optionally, the fourth indication information may be included in the second PDU session update request message, which is used to instruct the intermediate session management network element to update the second PDU session. The second PDU session update request message may be Nsmf_PDUSession_Update request.

[0205] Optionally, the fourth indication information can be a value of the third field. The value of the third field can be at least one bit or an enumerated value, without restriction. The third field can be implemented in any of the following ways:

[0206] Method 2.1: The third field can be a newly added field or an existing field in the second PDU session update request message. Specifically, the second PDU session update request message can be an Nsmf_PDUSession_Update request.

[0207] Method 2.2: The third field can be a newly added field or an existing field in the second information. The second information is used to indicate the PFCP session between the intermediate session management network element and the target user plane network element, and the second information can be N4 information. Optionally, the second information can be included in the second PDU session update request message.

[0208] Method 2.3: The third field can be a field from the third information element. The third information element is the forwarding action information element in the sixth packet forwarding rule, or an information element with a similar definition or function, or an extended field information element; there are no restrictions here. The sixth packet forwarding rule can be the rule corresponding to the forwarding of data packets from the target user plane network element to the data network by the target user plane network element. Optionally, the sixth packet forwarding rule can be included in the second information.

[0209] For example, when the value of the third field is 1, it is used to instruct the target user plane network element to cache uplink data packets; when the value of the third field is 0, it is used to instruct the target user plane network element not to cache uplink data packets or has no meaning; or, when the value of the third field is 0, it is used to instruct the target user plane network element to cache uplink data packets; when the value of the third field is 1, it is used to instruct the target user plane network element not to cache uplink data packets or has no meaning, and no restrictions are imposed here.

[0210] Specifically, for method 2.3, the value of the third field can be the value of the buffer bit in the third information cell. The value of the buffer bit can be a second value, which can be 0, 1, or other values, without restriction. It is understood that in this application, the forwarding rule for the sixth data packet can be the same as the forwarding rule for the fifth data packet.

[0211] 405. The intermediate session management network element sends the fifth instruction information to the target user plane network element according to the fourth instruction information. The fifth instruction information is used to instruct the target user plane network element to forward the uplink data packet.

[0212] Correspondingly, the target user plane network element receives the fifth instruction information from the intermediate session management network element.

[0213] Optionally, for methods 2.2 and 2.3 in step 404, the fourth indication information and the fifth indication information are the same. That is, step 404 can be replaced by: the intermediate session management network element sending the fourth indication information to the target user plane network element, wherein the fourth indication information can be included in the packet forwarding control protocol session update request message, which is used to instruct the target user plane network element to update the PFCP session of the terminal equipment.

[0214] Optionally, for method 2.1 in step 404, the fifth indication information can be a value of the fourth field. The value of the fourth field can be at least one bit value or an enumerated value, without limitation. The fourth field can be a field in the fourth information element, which is a forwarding action information element in the sixth data packet forwarding rule, or an information element with a similar definition or function, or an information element of an extended field, without limitation. In other words, for method 2.1 in step 404, the intermediate session management network element can receive the sixth data packet forwarding rule from the session management network element. Therefore, the intermediate session management network element can send the sixth data packet forwarding rule to the target user plane network element according to the fourth indication information. The sixth data packet forwarding rule can be included in the data packet forwarding control protocol session update request message, which is used to instruct the target user plane network element to update the PFCP session of the terminal device.

[0215] The third information cell can be the same as or different from the fourth information cell; no restrictions are imposed here.

[0216] The third field can be the same as or different from the fourth field; there are no restrictions here.

[0217] For example, when the value of the fourth field is 1, it is used to instruct the target user plane network element to cache uplink data packets; when the value of the fourth field is 0, it is used to instruct the target user plane network element not to cache uplink data packets or to have no meaning. Alternatively, when the value of the fourth field is 0, it is used to instruct the target user plane network element to cache uplink data packets; when the value of the fourth field is 1, it is used to instruct the target user plane network element not to cache uplink data packets or to have no meaning. No restrictions are imposed here.

[0218] As can be seen, in the above technical solution, the intermediate session management network element sends a first indication message to the session management network element, enabling the session management network element to know that the intermediate session management network element has inserted the target offloading user plane network element and the target user plane network element, and has deleted the source offloading user plane network element and the source user plane network element. This allows the intermediate session management network element to send a third indication message to the target user plane network element based on the second indication message from the session management network element, thus allowing the target user plane network element to buffer uplink data packets according to the third indication message. Simultaneously, when the session management network element learns that the target application network element has completed the handover, it can send a fourth indication message to the intermediate session management network element, enabling the intermediate session management network element to send a fifth indication message to the target user plane network element based on the fourth indication message, thus allowing the target user plane network element to forward uplink data packets according to the fifth indication message. It is understandable that because the target user plane network element does not forward uplink data packets before the target application network element completes the handover, but instead buffers the uplink data packets before the target application network element completes the handover, the uplink data packets are not forwarded, thus avoiding uplink data packet loss. In addition, since the target user plane network element forwards the uplink data packet only after the target application network element has completed the handover, the uplink data packet can be forwarded to the target application network element, which improves the continuity and reliability of data packet transmission.

[0219] Optionally, the method may further include: the intermediate session management network element sending a first packet forwarding control protocol request message to the user plane network element, the first packet forwarding control protocol request message including a first packet detection rule and a first packet forwarding rule. Correspondingly, the user plane network element receives the first packet forwarding control protocol request message from the intermediate session management network element.

[0220] Specifically, if the user plane network element is a source offloading user plane network element, the first data packet detection rule is the rule corresponding to the data packets from the target offloading user plane network element detected by the source offloading user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packets from the target offloading user plane network element forwarded by the source offloading user plane network element to the source offloading user plane network element; if the user plane network element is a target offloading user plane network element, the first data packet detection rule is the rule corresponding to the data packets from the target access network device detected by the target offloading user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packets from the target access network device forwarded by the target offloading user plane network element to the source offloading user plane network element.

[0221] Optionally, the first packet forwarding control protocol request message is used to instruct the user plane network element to establish or update the PFCP session of the terminal equipment. If the user plane network element is a source offloading user plane network element, the first packet forwarding control protocol request message is used to instruct the source offloading user plane network element to update the PFCP session of the terminal equipment. The first packet forwarding control protocol request message can be a packet forwarding control protocol session modification request message (PFCP session modification request) or a packet forwarding control protocol session establishment request message (PFCP session establishment request).

[0222] Optionally, after receiving the first data packet forwarding control protocol request message, the user plane network element may also send a first data packet forwarding control protocol response message to the intermediate session management network element. The first data packet forwarding control protocol response message is used to indicate to the user plane network element that it has successfully established or updated the PFCP session of the terminal device.

[0223] For example, after receiving the first packet forwarding control protocol request message, the source offloading user plane network element can also send a first packet forwarding control protocol response message to the intermediate session management network element. The first packet forwarding control protocol response message is used to indicate that the source offloading user plane network element has successfully updated the PFCP session of the terminal device. The first packet forwarding control protocol response message can be a packet forwarding control protocol session modification response message. After receiving the first packet forwarding control protocol request message, the target offloading user plane network element can also send a first packet forwarding control protocol response message to the intermediate session management network element. The first packet forwarding control protocol response message is used to indicate that the target offloading user plane network element has successfully established or updated the PFCP session of the terminal device. The first packet forwarding control protocol response message can be a packet forwarding control protocol session modification response message or a packet forwarding control protocol session establishment response message. Understandably, if the first packet forwarding control protocol request message is used to instruct the target offloading user plane network element to establish a PFCP session for the terminal device, the first packet forwarding control protocol response message is used to instruct the target offloading user plane network element to successfully establish a PFCP session for the terminal device; if the first packet forwarding control protocol request message is used to instruct the target offloading user plane network element to update the PFCP session for the terminal device, the first packet forwarding control protocol response message is used to instruct the target offloading user plane network element to successfully update the PFCP session for the terminal device.

[0224] Optionally, the first data packet detection rule is the uplink data packet detection rule, and the first data packet forwarding rule is the uplink data packet forwarding rule.

[0225] Optionally, the first packet forwarding control protocol request message may further include a third packet detection rule and a third packet forwarding rule. If the user plane network element is the source offloading user plane network element, the third packet forwarding rule corresponds to the rule for the source offloading user plane network element to forward packets from the remote user plane network element to the target offloading user plane network element; or, the third packet detection rule corresponds to the rule for the source offloading user plane network element to detect packets from the source user plane network element, and the third packet forwarding rule corresponds to the rule for the source offloading user plane network element to forward packets from the source user plane network element to the target offloading user plane network element. If the user plane network element is the target offloading user plane network element, the third packet detection rule corresponds to the rule for the target offloading user plane network element to detect packets from the source offloading user plane network element, and the third packet forwarding rule corresponds to the rule for the target offloading user plane network element to forward packets from the source offloading user plane network element to the target access network device.

[0226] Optionally, the third data packet detection rule is the downlink data packet detection rule, and the third data packet forwarding rule is the downlink data packet forwarding rule.

[0227] As can be seen, in the above technical solution, the intermediate session management network element can send a first data packet forwarding control protocol request message to the source offloading user plane network element or the target offloading user plane network element. The first data packet forwarding control protocol request message includes a first data packet detection rule and a first data packet forwarding rule, so that the source offloading user plane network element or the target offloading user plane network element detects data packets according to the first data packet detection rule and forwards data packets according to the first data packet forwarding rule, thereby avoiding the loss of uplink data packets of the terminal device and improving the continuity and reliability of data packet transmission.

[0228] Optionally, the method may further include: the intermediate session management network element receiving a second data packet detection rule, a second data packet forwarding rule, and a sixth indication information from the session management network element. Correspondingly, the session management network element sends the second data packet detection rule, the second data packet forwarding rule, and the sixth indication information to the intermediate session management network element.

[0229] Optionally, before the intermediate session management network element sends the first data packet forwarding control protocol request message to the user plane network element, the intermediate session management network element receives the second data packet detection rule, the second data packet forwarding rule, and the sixth indication information from the session management network element.

[0230] The second data packet detection rule is a rule for detecting data packets from the target access network device, and the second data packet forwarding rule is a rule for forwarding data packets from the target access network device to the source user plane network element; or, the second data packet detection rule is a rule for detecting data packets from the target user plane network element, and the second data packet forwarding rule is a rule for forwarding data packets from the target user plane network element to the source user plane network element.

[0231] Optionally, the second packet detection rule and the second packet forwarding rule can be included in the third information, which can be N4 information. It is understood that the third information is used to instruct the intermediate session management element to delete or update the PFCP session with the source offloading user plane element; or, the third information is used to instruct the intermediate session management element to establish a PFCP session with the target offloading user plane element. For example, if the second packet detection rule is a rule for detecting packets from the target offloaded user plane network element, the third information is used to instruct the intermediate session management network element to delete or update the PFCP session with the source offloaded user plane network element; if the second packet forwarding rule is a rule for forwarding packets from the target offloaded user plane network element to the source user plane network element, the third information is used to instruct the intermediate session management network element to delete or update the PFCP session with the source offloaded user plane network element; if the second packet detection rule is a rule for detecting packets from the target access network device, the third information is used to instruct the intermediate session management network element to establish a PFCP session with the target offloaded user plane network element; if the second packet forwarding rule is a rule for forwarding packets from the target access network device to the source offloaded user plane network element, the third information is used to instruct the intermediate session management network element to establish a PFCP session with the target offloaded user plane network element. Additionally, the third information can be included in the first PDU session update response message.

[0232] Optionally, the second data packet detection rule is the uplink data packet detection rule, and the second data packet forwarding rule is the uplink data packet forwarding rule.

[0233] The sixth indication information is used to indicate one or more of the following: the second data packet detection rule is the rule corresponding to the detection of data packets by the source diversion user plane network element or the target diversion user plane network element; the second data packet forwarding rule is the rule corresponding to the forwarding of data packets by the source diversion user plane network element or the target diversion user plane network element.

[0234] For example, the sixth indication information is used to indicate one or more of the following: the second data packet detection rule is the rule corresponding to the data packet detected by the source-splitting user plane network element, and the second data packet forwarding rule is the rule corresponding to the data packet forwarded by the source-splitting user plane network element.

[0235] For example, the sixth instruction information is used to indicate one or more of the following: the second data packet detection rule is the rule corresponding to the target off-line user plane network element detecting data packets, and the second data packet forwarding rule is the rule corresponding to the target off-line user plane network element forwarding data packets.

[0236] Optionally, the sixth indication information can be a value of the fifth field. The value of the fifth field can be at least one bit or an enumerated value, without restriction. The fifth field can be implemented in any of the following ways:

[0237] Method 3.1: The fifth field can be a newly added field or an existing field in the first PDU session update request message.

[0238] Method 3.2: The fifth field can be a newly added field or an existing field in the third information.

[0239] Method 3.3: The fifth field can be a field in the fifth information element. Specifically, the fifth information element can be a forwarding action information element in the second data packet detection rule or the second data packet forwarding rule, or an information element with a similar definition or function, or an extended field information element; no restrictions are placed here.

[0240] For example, when the value of the fifth field is 1, it indicates one or more of the following: the second data packet detection rule is the rule corresponding to the data packet detected by the source-splitting user plane network element, and the second data packet forwarding rule is the rule corresponding to the data packet forwarded by the source-splitting user plane network element. When the value of the fifth field is 0, it indicates one or more of the following: the second data packet detection rule is not the rule corresponding to the data packet detected by the source-splitting user plane network element, and the second data packet forwarding rule is not the rule corresponding to the data packet forwarded by the source-splitting user plane network element, or it has no meaning. Alternatively, when the value of the fifth field is 0, it indicates one or more of the following: the second data packet detection rule is the rule corresponding to the data packet detected by the source-splitting user plane network element, and the second data packet forwarding rule is the rule corresponding to the data packet forwarded by the source-splitting user plane network element. When the value of the fifth field is 1, it indicates one or more of the following: the second data packet detection rule is not the rule corresponding to the data packet detected by the source-splitting user plane network element, and the second data packet forwarding rule is not the rule corresponding to the data packet forwarded by the source-splitting user plane network element, or it has no meaning. No restrictions are imposed here.

[0241] Optionally, the sixth indication information can be a forwarding tunnel rule indication.

[0242] As can be seen, in the above technical solution, the intermediate session management network element can receive the second data packet detection rule, the second data packet forwarding rule, and the sixth indication information from the session management network element, so that the intermediate session management network element can know one or more of the following: the second data packet detection rule is the rule corresponding to the data packet detected by the source diversion user plane network element or the target diversion user plane network element; the second data packet forwarding rule is the rule corresponding to the data packet forwarded by the source diversion user plane network element or the target diversion user plane network element.

[0243] Optionally, if the user plane network element is the target offloading user plane network element, the first packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element to the second packet detection rule according to the sixth instruction information. The first packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the source offloading user plane network element to the second packet forwarding rule according to the sixth instruction information. If the user plane network element is the source offloading user plane network element, the first packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the source offloading user plane network element to the second packet detection rule according to the sixth instruction information. The first packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element to the second packet forwarding rule according to the sixth instruction information.

[0244] The tunnel endpoint identifier and Internet Protocol (IP) address of the target offloaded user plane network element are used to instruct the target offloaded user plane network element to receive uplink service data packets. Similarly, the tunnel endpoint identifier and IP address of the source offloaded user plane network element are used to instruct the source offloaded user plane network element to receive uplink service data packets.

[0245] The sixth instruction can be "Y".

[0246] For example, referring to Table 1, the second packet detection rule and the second packet forwarding rule described in Table 1 are contained in the N4 information of the session management network element instructing the intermediate session management network element to establish a PFCP session with the target offloading user plane network element. Table 1 shows the correspondence between the packet detection rule, the packet forwarding rule, and the indication information. As shown in Table 1, there is a correspondence between UL PDR259 (identifier of the second packet detection rule), the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element (the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element are included in the first packet forwarding rule), Access (source interface), N3 (source interface type), ULFAR 259 (identifier of the second packet forwarding rule), Core (target interface), N9 (target interface type), and the sixth indication information. Because the sixth indication information is "Y", the intermediate session management network element can add the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the second packet forwarding rule according to the sixth indication information to obtain the first packet forwarding rule.

[0247] Table 1: Correspondence between packet detection rules, packet forwarding rules, and indication information

[0248]

[0249] As can be seen, in the above technical solution, since the first data packet detection rule also includes the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element, and the first data packet forwarding rule also includes the tunnel endpoint identifier and the Internet Protocol address of the source offloading user plane network element, the target offloading user plane network element can receive and detect data packets based on the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element, and establish a tunnel with the source offloading user plane network element based on the tunnel endpoint identifier and the Internet Protocol address of the source offloading user plane network element, so that data packets can be transmitted through the tunnel, avoiding the loss of uplink data packets of the terminal device. Similarly, since the first data packet detection rule also includes the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element, and the first data packet forwarding rule also includes the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element, the source user plane network element can receive and detect data packets based on the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element. It can also establish a tunnel with the source user plane network element based on the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element, so that data packets can be transmitted through the tunnel, avoiding the loss of uplink data packets of the terminal device.

[0250] See Figure 5 , Figure 5 This is a flowchart illustrating a message transmission method provided in an embodiment of this application. Figure 5 As shown, the method includes, but is not limited to, the following steps:

[0251] 501. The intermediate session management network element sends a third packet forwarding control protocol request message to the user plane network element. The third packet forwarding control protocol request message includes the third packet detection rules and the third packet forwarding rules.

[0252] Correspondingly, the user plane network element receives the third data packet forwarding control protocol request message from the intermediate session management network element.

[0253] For details regarding the rules for third-party packet detection and third-party packet forwarding, please refer to [link / reference]. Figure 4 The relevant description of step 405 will not be repeated here.

[0254] Optionally, the third packet forwarding control protocol request message is used to instruct user plane network elements to establish or update the PFCP session of the terminal equipment. If the user plane network element is a source offloading user plane network element, the third packet forwarding control protocol request message is used to instruct the source offloading user plane network element to update the PFCP session of the terminal equipment. The third packet forwarding control protocol request message can be a packet forwarding control protocol session modification request message (PFCP session modification request). If the user plane network element is a target offloading user plane network element, the third packet forwarding control protocol request message is used to instruct the target offloading user plane network element to establish or update the PFCP session of the terminal equipment. The third packet forwarding control protocol request message can be a packet forwarding control protocol session modification request message (PFCP session modification request) or a packet forwarding control protocol session establishment request message (PFCP session establishment request).

[0255] Optionally, after receiving the third packet forwarding control protocol request message, the user plane network element may also send a third packet forwarding control protocol response message to the intermediate session management network element. The third packet forwarding control protocol response message is used to indicate to the user plane network element that the PFCP session of the terminal device has been successfully established or updated.

[0256] For example, after receiving the third packet forwarding control protocol request message, the source offloading user plane network element can also send a third packet forwarding control protocol response message to the intermediate session management network element. The third packet forwarding control protocol response message is used to indicate that the source offloading user plane network element has successfully updated the PFCP session of the terminal device. After receiving the third packet forwarding control protocol request message, the target offloading user plane network element can also send a third packet forwarding control protocol response message to the intermediate session management network element. The third packet forwarding control protocol response message is used to indicate that the target offloading user plane network element has successfully established or updated the PFCP session of the terminal device. The third packet forwarding control protocol response message can be a packet forwarding control protocol session modification response message or a packet forwarding control protocol session establishment response message. Understandably, if the third packet forwarding control protocol request message is used to instruct the target offloading user plane network element to establish a PFCP session for the terminal device, the third packet forwarding control protocol response message is used to instruct the target offloading user plane network element to successfully establish a PFCP session for the terminal device; if the third packet forwarding control protocol request message is used to instruct the target offloading user plane network element to update the PFCP session for the terminal device, the third packet forwarding control protocol response message is used to instruct the target offloading user plane network element to successfully update the PFCP session for the terminal device.

[0257] Optionally, the third packet forwarding control protocol request message may also include the first packet detection rule and the first packet forwarding rule.

[0258] Optionally, in this application, the first data packet forwarding control protocol request message may be the same message or a different message from the third data packet forwarding control protocol request message; this is not limited. If the first data packet forwarding control protocol request message and the third data packet forwarding control protocol request message are the same message, the first data packet forwarding control protocol response message may be the same message from the third data packet forwarding control protocol response message; this is not limited.

[0259] As can be seen, in the above technical solution, the intermediate session management network element can send a third data packet forwarding control protocol request message to the source diversion user plane network element or the target diversion user plane network element. The third data packet forwarding control protocol request message includes the third data packet detection rule and the third data packet forwarding rule, so that the source diversion user plane network element or the target diversion user plane network element detects data packets according to the third data packet detection rule and forwards data packets according to the third data packet forwarding rule, thereby avoiding the loss of downlink data packets of the terminal device and improving the reliability of data packet transmission.

[0260] Optionally, the method may further include: the intermediate session management network element receiving the fourth data packet detection rule, the fourth data packet forwarding rule, and the seventh indication information from the session management network element. Correspondingly, the session management network element sends the fourth data packet detection rule, the fourth data packet forwarding rule, and the seventh indication information to the intermediate session management network element.

[0261] Optionally, before the intermediate session management network element sends the third data packet forwarding control protocol request message to the user plane network element, the intermediate session management network element receives the fourth data packet detection rule, the fourth data packet forwarding rule, and the seventh indication information from the session management network element.

[0262] Optionally, the fourth packet detection rule is a rule for detecting packets from the source offloading user plane network element, and the fourth packet forwarding rule is a rule for forwarding packets from the source offloading user plane network element to the target access network device; or,

[0263] The fourth packet detection rule is the rule for detecting packets from remote user plane network elements, and the fourth packet forwarding rule is the rule for forwarding packets from remote user plane network elements to the target offloading user plane network element; or,

[0264] The fourth packet detection rule is the rule for detecting packets from the source user plane network element, and the fourth packet forwarding rule is the rule for forwarding packets from the source user plane network element to the target offloading user plane network element.

[0265] Optionally, the fourth packet detection rule and the fourth packet forwarding rule can be included in the fourth information, which can be N4 information. It is understood that the fourth information is used to instruct the intermediate session management network element to delete or update the PFCP session with the source offloading user plane network element; or, the fourth information is used to instruct the intermediate session management network element to establish a PFCP session with the target offloading user plane network element. For example, if the fourth packet detection rule is a rule for detecting packets from a remote user plane network element, the fourth information is used to instruct the intermediate session management network element to delete or update the PFCP session with the source offloading user plane network element; if the fourth packet forwarding rule is a rule for forwarding packets from a remote user plane network element to the target offloading user plane network element, the fourth information is used to instruct the intermediate session management network element to delete or update the PFCP session with the source offloading user plane network element; if the fourth packet detection rule is a rule for detecting packets from a source user plane network element, the fourth information is used to instruct the intermediate session management network element to delete or update the PFCP session with the source offloading user plane network element; if the fourth packet detection rule is a rule for detecting packets from a source user plane network element, the fourth information is used to instruct the intermediate session management network element to delete or update the PFCP session with the source offloading user plane network element; if the fourth packet detection rule is a rule for detecting packets from a source user plane network element, the fourth information is used to instruct the intermediate session management network element to delete or update the PFCP session with the source offloading user plane network element; if the fourth packet forwarding rule is a rule for forwarding packets from a remote ... The fourth packet forwarding rule is a rule that forwards packets from the source user plane network element to the target offloading user plane network element. The fourth information is used to instruct the intermediate session management network element to delete or update the PFCP session with the source offloading user plane network element. If the fourth packet detection rule is a rule that detects packets from the source offloading user plane network element, the fourth information is used to instruct the intermediate session management network element to establish a PFCP session with the target offloading user plane network element. If the fourth packet forwarding rule is a rule that forwards packets from the source offloading user plane network element to the target access network device, the fourth information is used to instruct the intermediate session management network element to establish a PFCP session with the target offloading user plane network element. Additionally, the fourth information can be included in the first PDU session update response message.

[0266] Among them, the fourth data packet detection rule is the downlink data packet detection rule, and the fourth data packet forwarding rule is the downlink data packet forwarding rule.

[0267] The seventh indication information is used to indicate one or more of the following: the fourth data packet detection rule is the rule corresponding to the detection of data packets by the source diversion user plane network element or the target diversion user plane network element; the fourth data packet forwarding rule is the rule corresponding to the forwarding of data packets by the source diversion user plane network element or the target diversion user plane network element.

[0268] For example, the seventh indication information is used to indicate one or more of the following: the fourth packet detection rule is the rule corresponding to the source-splitting user plane network element detecting packets, and the fourth packet forwarding rule is the rule corresponding to the source-splitting user plane network element forwarding packets.

[0269] For example, the seventh instruction information is used to indicate one or more of the following: the fourth packet detection rule is the rule corresponding to the target diverted user plane network element detecting packets, and the fourth packet forwarding rule is the rule corresponding to the target diverted user plane network element forwarding packets.

[0270] Optionally, the seventh indication information can be a value of the sixth field. The value of the sixth field can be at least one bit or an enumerated value, without restriction. The sixth field can be implemented in any of the following ways:

[0271] Method 4.1: The sixth field can be a newly added field or an existing field in the first PDU session update request message.

[0272] Method 4.2: The sixth field can be a newly added field or an existing field in the fourth information.

[0273] Method 4.3: The sixth field can be a field in the sixth information element. Specifically, the sixth information element can be a forwarding action information element in the fourth packet detection rule or the fourth packet forwarding rule, or an information element with a similar definition or function, or an extended field information element; no restrictions are placed here.

[0274] For example, when the value of the sixth field is 1, it indicates one or more of the following: the fourth packet detection rule is the rule corresponding to the packet detected by the source-splitting user plane network element, and the fourth packet forwarding rule is the rule corresponding to the packet forwarded by the source-splitting user plane network element. When the value of the sixth field is 0, it indicates one or more of the following: the fourth packet detection rule is not the rule corresponding to the packet detected by the source-splitting user plane network element, and the fourth packet forwarding rule is not the rule corresponding to the packet forwarded by the source-splitting user plane network element, or it has no meaning. Alternatively, when the value of the sixth field is 0, it indicates one or more of the following: the fourth packet detection rule is the rule corresponding to the packet detected by the source-splitting user plane network element, and the fourth packet forwarding rule is the rule corresponding to the packet forwarded by the source-splitting user plane network element. When the value of the sixth field is 1, it indicates one or more of the following: the fourth packet detection rule is not the rule corresponding to the packet detected by the source-splitting user plane network element, and the fourth packet forwarding rule is not the rule corresponding to the packet forwarded by the source-splitting user plane network element, or it has no meaning. No restrictions are imposed here.

[0275] Optionally, the seventh indication information can be a forwarding tunnel rule indication.

[0276] In this application, the sixth and seventh instruction information can be the same. For example, both the sixth and seventh instruction information can be "Y".

[0277] For example, refer to Table 2, which shows the correspondence between packet detection rules, packet forwarding rules, and indication information. As shown in Table 2, the fourth packet detection rule and the fourth packet forwarding rule described in Table 2 are contained in the N4 information of the PFCP session between the session management network element and the source offloading user plane network element, which instructs the intermediate session management network element to delete or update the session. There is a correspondence between DL PDR 258 ​​(identifier of the fourth packet detection rule), the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element, Core (source interface), N9 (source interface type), DLFAR 258 ​​(identifier of the fourth packet forwarding rule), Access (target interface), N3 (target interface type), and the seventh indication information. Because the seventh indication information is "Y", the intermediate session management network element can add the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element to the fourth packet forwarding rule according to the seventh indication information.

[0278] Table 2: Correspondence between packet detection rules, packet forwarding rules, and indication information

[0279]

[0280] As can be seen, in the above technical solution, the intermediate session management network element can receive the fourth data packet detection rule, the fourth data packet forwarding rule, and the seventh indication information from the session management network element, so that the intermediate session management network element can know one or more of the following: the fourth data packet detection rule is the rule corresponding to the data packet detected by the source diversion user plane network element or the target diversion user plane network element; the fourth data packet forwarding rule is the rule corresponding to the data packet forwarded by the source diversion user plane network element or the target diversion user plane network element.

[0281] Optionally, if the user plane network element is the target offloading user plane network element, the third packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element to the fourth packet detection rule according to the seventh instruction information. The third packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target access network device to the fourth packet forwarding rule according to the seventh instruction information. If the user plane network element is the source offloading user plane network element, the third packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the source offloading user plane network element to the fourth packet detection rule according to the seventh instruction information. The third packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element to the fourth packet forwarding rule according to the seventh instruction information.

[0282] As can be seen, in the above technical solution, since the third data packet detection rule also includes the tunnel endpoint identifier and Internet Protocol address of the target offloading user plane network element, and the third data packet forwarding rule also includes the tunnel endpoint identifier and Internet Protocol address of the target access network device, the target offloading user plane network element can receive and detect data packets based on the tunnel endpoint identifier and Internet Protocol address of the target offloading user plane network element, and establish a tunnel with the target access network device based on the tunnel endpoint identifier and Internet Protocol address of the target access network device, so that data packets can be transmitted through the tunnel, avoiding the loss of data packets between the target offloading user plane network element and the target access network device. Similarly, since the third packet detection rule also includes the tunnel endpoint identifier and Internet Protocol (IP) address of the source user plane network element, and the third packet forwarding rule also includes the tunnel endpoint identifier and IP address of the target user plane network element, the source user plane network element can receive and detect packets based on the tunnel endpoint identifier and IP address of the source user plane network element, and establish a tunnel with the target user plane network element based on the tunnel endpoint identifier and IP address of the target user plane network element. This allows packets to be transmitted through the tunnel, avoiding the loss of downlink packets from the terminal device.

[0283] The following example illustrates this scheme using the intermediate session management network element determining the establishment of a service data packet forwarding tunnel with a user plane network element (which can refer to the target user plane network element and / or the target offloading user plane element) based on the N3 interface between the source offloading user plane network element and the source access network device. For details, see [link to relevant documentation]. Figure 6A , Figure 6A This is a schematic diagram illustrating another message transmission process provided in an embodiment of this application. For example... Figure 6A As shown, the method includes, but is not limited to, the following steps:

[0284] 601. The intermediate session management network element sends the first PFCP session establishment request message to the target user plane network element. The PFCP session establishment request message is used to notify the target user plane network element to establish a PFCP session for the terminal device.

[0285] Correspondingly, the target user plane network element receives the first PFCP session establishment request message from the intermediate session management network element.

[0286] In step 601, the first PFCP session establishment request message includes a first uplink data packet detection rule and a first uplink data packet forwarding rule, as well as a first downlink data packet detection rule and a first downlink data packet forwarding rule. The first uplink data packet detection rule and the first uplink data packet forwarding rule are used by the target user plane network element to establish an uplink forwarding channel for all service data packets, and the first downlink data packet detection rule and the first downlink data packet forwarding rule are used by the target user plane network element to establish a downlink forwarding channel for all service data packets. It can be understood that uplink service data packets are received by the target user plane network element and forwarded to the data network, while downlink service data packets are received by the target user plane network element and forwarded to the target distribution user plane network element.

[0287] 602. The target user plane network element replies with the first PFCP session establishment response message to the intermediate session management network element. The first PFCP session establishment response message indicates that the first PFCP session was successfully established.

[0288] Correspondingly, the intermediate session management network element receives the first PFCP session establishment response message from the target user plane network element.

[0289] In step 602, the PFCP session establishment response message contains service data packet forwarding information allocated by the target user plane network element. The service data packet forwarding information includes the tunnel endpoint identifier and the Internet Protocol address of the target user plane network element. The tunnel endpoint identifier and the Internet Protocol address of the target user plane network element are used by the intermediate session management network element to instruct the target offloading user plane network element to establish an uplink service data packet forwarding channel.

[0290] Understandable. Figure 6A In the illustrated embodiment, the intermediate session management network element determines and establishes the forwarding tunnel for uplink or downlink service data packets to ensure the continuity of uplink or downlink service data packets during processes where both the user plane network element and the user plane network element change simultaneously. For example, the intermediate session management network element determines whether an uplink or downlink service data packet forwarding tunnel needs to be established based on whether an N3 user plane tunnel has been established between the source user plane network element and the source access network device. That is, if an N3 user plane tunnel has been established between the source user plane network element and the source access network device, the intermediate session management network element determines that an uplink or downlink service data packet forwarding tunnel needs to be established.

[0291] 603. The intermediate session management network element sends a second PFCP session establishment request message to the target offloading user plane network element. The PFCP session establishment request message is used to notify the target offloading user plane network element to establish a PFCP session for the terminal device.

[0292] Correspondingly, the target offloading user plane network element receives the second PFCP session establishment request message from the intermediate session management network element.

[0293] The second PFCP session establishment request message in step 603 includes a first uplink data packet detection rule, a first uplink data packet forwarding rule, a first downlink data packet detection rule, and a first downlink data packet forwarding rule. The first uplink data packet detection rule and the first uplink data packet forwarding rule are used by the target offloading user plane network element to establish an uplink forwarding channel for all service data packets, and the first downlink data packet detection rule and the first downlink data packet forwarding rule are used by the target offloading user plane network element to establish a downlink forwarding channel for all service data packets. It can be understood that uplink service data packets are sent from the target access network device to the target offloading user plane network element, and then forwarded by the target offloading user plane network element to the remote user plane network element; downlink service data packets are sent from the remote user plane network element to the target offloading user plane network element, and then forwarded by the target offloading user plane network element to the target access network device.

[0294] In addition, the second PFCP session establishment request message in step 603 also includes a second downlink data packet detection rule and a second downlink data packet forwarding rule. These rules are used by the target offloading user plane network element to establish a forwarding channel for downlink service data packets, ensuring the continuity of downlink service data packets during processes where both the offloading user plane network element and the user plane network element change simultaneously. Downlink service data packets are sent from the source offloading user plane network element to the target offloading user plane network element, and then forwarded by the target offloading user plane network element to the target access network device. It is understandable that the second PFCP session establishment request message in step 603 and... Figure 5 The third PFCP request message sent by the intermediate session management network element to the target offloading user plane network element in step 501 is the same message, and the second downlink data packet detection rule in step 603 is the same as... Figure 5 The detection rules for the third data packet sent by the intermediate session management network element to the target offloading user plane network element in step 501 are the same, and the forwarding rules for the second downlink data packet are the same. Figure 5 The forwarding rules for the third data packet sent by the intermediate session management network element to the target offloading user plane network element in step 501 are the same.

[0295] 604. The target user plane network element replies with a second PFCP session establishment response message to the intermediate session management network element. The second PFCP session establishment response message is used to indicate that the second PFCP session has been successfully established.

[0296] Correspondingly, the intermediate session management network element receives the second PFCP session establishment response message from the target offloading user plane network element.

[0297] In step 604, the second PFCP session establishment response message includes first service data packet forwarding information, second service data packet forwarding information, and third service data packet forwarding information allocated by the target offloading user plane network element. The first, second, and third service data packet forwarding information all include the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element. The first service data packet forwarding information is used by the intermediate session management network element to instruct the target access network device to establish an uplink service data packet forwarding channel. The second service data packet forwarding information is used by the intermediate session management network element to instruct the target user plane network element or the remote user plane network element to establish a downlink service data packet forwarding channel. The third service data packet forwarding information is used by the intermediate session management network element to instruct the source offloading user plane network element to establish a downlink service data packet forwarding channel to ensure the continuity of downlink service data packets.

[0298] 605. The intermediate session management network element sends a first PFCP session update request message to the source offloading user plane network element. The first PFCP session update request message is used to notify the source offloading user plane network element to update the third PFCP session of the terminal equipment.

[0299] Correspondingly, the source-splitting user plane network element receives the first PFCP session update request message from the intermediate session management network element.

[0300] In step 605, the first PFCP session update request message includes a first uplink data packet detection rule, a first uplink data packet forwarding rule, a first downlink data packet detection rule, and a first downlink data packet forwarding rule. The first uplink data packet detection rule and the first uplink data packet forwarding rule are used by the source user plane network element to establish an uplink forwarding channel for service data packets diverted from the source user plane network element. The first downlink data packet detection rule and the first downlink data packet forwarding rule are used by the source user plane network element to establish a downlink forwarding channel for all service data packets, ensuring the continuity of uplink or downlink service data packets during processes where both the diverting user plane network element and the user plane network element change simultaneously. It can be understood that uplink service data packets are sent from the target diverting user plane network element to the source diverting user plane network element, and then forwarded from the source diverting user plane network element back to the source user plane network element. Downlink service data packets are sent from the remote user plane network element to the source diverting user plane network element, or from the source user plane network element to the source diverting user plane network element, and then forwarded from the source diverting user plane network element to the target diverting user plane network element. Understandably, the first PFCP session update request message in step 605 and Figure 4 In step 405, the first data packet forwarding control protocol request message sent by the intermediate session management network element to the source offloading user plane network element is the same message, and the first uplink data packet detection rule in step 605 is the same as... Figure 4In step 405, the first data packet detection rule sent by the intermediate session management network element to the source offloading user plane network element is the same, and the first uplink data packet forwarding rule is the same as... Figure 4 The forwarding rules for the first data packet sent by the intermediate session management network element to the source offloading user plane network element in step 405 are the same. The first PFCP session update request message in step 605 is... Figure 5 The third data packet forwarding control protocol request message sent by the intermediate session management network element to the source offloading user plane network element in step 501 is the same message, and the first downlink data packet detection rule in step 605 is the same as... Figure 5 In step 501, the third data packet detection rule sent by the intermediate session management network element to the source offloading user plane network element is the same, and the first downlink data packet forwarding rule is the same. Figure 5 The forwarding rules for the third data packet sent by the intermediate session management network element to the source diversion user plane network element in step 501 are the same.

[0301] 606. The source-splitting user plane network element replies with the first PFCP session update response message to the intermediate session management network element. The first PFCP session update response message indicates that the third PFCP session has been successfully updated.

[0302] Correspondingly, the intermediate session management network element receives the first PFCP session update response message from the source-splitting user plane network element.

[0303] In step 606, the first PFCP session update response message contains service packet forwarding information allocated by the source offloading user plane network element. This service packet forwarding information includes the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element. This service packet forwarding information is used by the intermediate session management network element to instruct the target offloading user plane network element to establish an uplink service packet forwarding channel to ensure the continuity of uplink service packets.

[0304] After step 606, the downlink service data packet forwarding path is as follows:

[0305] Remote user plane network element -> Source offloading user plane network element -> Target offloading user plane network element -> Target access network device -> Terminal device;

[0306] Source user plane network element -> Source offloading user plane network element -> Target offloading user plane network element -> Target access network device -> Terminal device.

[0307] Optionally, after step 606, this solution may also include, but is not limited to, the following steps 607-616. For details, please refer to... Figure 6B , Figure 6B This is a flowchart illustrating another message transmission method provided in an embodiment of this application.

[0308] 607. The intermediate session management network element sends a first PDU session update request (Nsmf_PDUSession_Updaterequest) to the session management network element. The first PDU session update request message contains first indication information and second service data packet forwarding information allocated by the target offloading user plane network element in step 604.

[0309] Correspondingly, the session management network element receives the first PDU session update request from the intermediate session management network element.

[0310] Regarding the first instruction information, please refer to... Figure 4 The relevant description of step 401 will not be repeated here.

[0311] 608. The session management network element replies to the intermediate session management network element with the first PDU session update response message (Nsmf_PDUSession_Updateresponse). The first PDU session update response message contains the first N4 information, the second N4 information, the third N4 information, and the fourth N4 information.

[0312] Correspondingly, the intermediate session management network element receives the first PDU session update response message from the session management network element.

[0313] The first N4 information is used to instruct the intermediate session management network element to establish a PFCP session between the intermediate session management network element and the target offloading user plane network element. The first N4 information includes a third uplink data packet detection rule, a third uplink data packet forwarding rule, a third downlink data packet detection rule, and a third downlink data packet forwarding rule. The third uplink data packet detection rule and the third uplink data packet forwarding rule are used to instruct the target offloading user plane network element to establish an uplink forwarding channel for service data packets offloaded from the target user plane network element. The third downlink data packet detection rule and the third downlink data packet forwarding rule are used to instruct the target offloading user plane network element to establish a downlink forwarding channel for service data packets offloaded from the target user plane network element. Uplink service data packets are sent from the target access network device to the target offloading user plane network element and then forwarded by the target offloading user plane network element to the target user plane network element. Downlink service data packets are sent from the target user plane network element to the target offloading user plane network element and then forwarded by the target offloading user plane network element to the target access network device. For example, for a service data packet corresponding to a service with an application identifier of 100, if it is diverted from the target user plane network element, the first N4 information contains the uplink data packet detection rules and uplink data packet forwarding rules corresponding to the service, or the first N4 information contains the downlink data packet detection rules and downlink data packet forwarding rules corresponding to the service.

[0314] The second N4 information is used to instruct the intermediate session management network element to establish a PFCP session between the intermediate session management network element and the target user plane network element. The second N4 information includes a second uplink packet detection rule, a second uplink packet forwarding rule, a second downlink packet detection rule, and a second downlink packet forwarding rule. The second uplink packet detection rule and the second uplink packet forwarding rule are used to instruct the target user plane network element to establish an uplink forwarding channel for service packets diverted from the target user plane network element. The second downlink packet detection rule and the second downlink packet forwarding rule are used to instruct the target user plane network element to establish a downlink forwarding channel for service packets diverted from the target user plane network element. It can be understood that uplink service packets are sent from the target diverted user plane network element to the target user plane network element, and then forwarded by the target user plane network element to the data network. Downlink service packets are sent from the data network to the target user plane network element, and then forwarded by the target user plane network element to the target diverted user plane network element.

[0315] Among them, the third N4 information is used to instruct the intermediate session management network element to delete the PFCP session between the intermediate session management network element and the source diversion user plane network element.

[0316] Among them, the fourth N4 information is used to instruct the intermediate session management network element to delete the PFCP session between the intermediate session management network element and the source user plane network element.

[0317] Furthermore, changes to local user plane network elements may lead to application network element switching. The session management network element can notify the source application network element of the access point identifier (DNAI) of the target user plane network element, so that the source application network element can trigger the application network element switching based on the access point identifier. If the application network element subscribes to the session management network element's events, it indicates that application network element confirmation is required. That is, the application network element can only send uplink data packets to the new application network element after performing the switch and sending a positive confirmation to the session management network element. In other words, when the source application network element switches to the target application network element, the target application network element can send a positive confirmation to the session management network element. Under these circumstances, the target user plane network element can send uplink data packets to the target application network element. Therefore, to implement this process, the first PDU session update response message in step 608 also includes second indication information. For more information on the second indication information, please refer to... Figure 4 The relevant description of step 402 is not repeated here.

[0318] For example, the second instruction information can be implemented in any of the following ways:

[0319] Case 1.1: The session management network element can instruct the target user plane network element to cache uplink data packets in the first PDU session update response message in step 608 through a bit or enumeration. For example, it can use a bit in the new or existing parameters to indicate this, where setting the bit to 1 indicates that the target user plane network element caches uplink data packets, and setting the bit to 0 indicates that the target user plane network element does not need to cache uplink data packets or forward uplink data packets, or has no special meaning; or setting the bit to 0 indicates that the target user plane network element caches uplink data packets, and setting the bit to 1 indicates that the target user plane network element does not need to cache uplink data packets or forward uplink data packets, or has no special meaning; or it can use enumeration in the new or existing parameters, with a specific enumeration value indicating that the target user plane network element caches uplink data packets.

[0320] Alternatively, in case 1.2: the session management network element may also instruct the target user plane network element to buffer uplink data packets in the second N4 information by using a bit or enumeration. The specific indication method can be referred to the indication method in case 1.1 above, and will not be elaborated here.

[0321] Alternatively, in case 1.3: the session management network element can set the cache bit in the forwarding action information element contained in the second uplink data packet forwarding rule contained in the second N4 information to 1 to instruct the target user plane network element to cache the uplink data packet.

[0322] 609. The session management network element sends a second PFCP session update request message to the remote user plane network element. The second PFCP session update request message is used to notify the remote user plane network element to update the PFCP session of the terminal equipment.

[0323] Correspondingly, the remote user plane network element receives the second PFCP session update request message from the session management network element.

[0324] In step 609, the second PFCP session update request message contains the second service data packet forwarding information allocated by the target offloading user plane network element in step 607. After receiving the downlink service data packet from the data network, the remote user plane network element sends the downlink service data packet to the target offloading user plane network element according to the second service data packet forwarding information allocated by the target offloading user plane network element.

[0325] 610. The remote user plane network element replies with the second PFCP session update response message to the session management network element. The second PFCP session update response message indicates that the fourth PFCP session has been successfully updated.

[0326] Correspondingly, the session management network element receives the PFCP session update response message from the remote user plane network element.

[0327] After step 610, the downlink service data packet forwarding path is as follows:

[0328] Remote user plane network element -> Target offloaded user plane network element -> Target access network device -> Terminal device;

[0329] Source user plane network element -> Source offloading user plane network element -> Target offloading user plane network element -> Target access network device -> Terminal device.

[0330] 611. The intermediate session management network element sends a third PFCP session update request message to the target offloading user plane network element. The third PFCP session update request message is used to notify the target offloading user plane network element to update the PFCP session of the terminal equipment.

[0331] Correspondingly, the target user plane network element receives the third PFCP session update request message from the intermediate session management network element.

[0332] The third PFCP session update request message in step 611 contains the third uplink data packet detection rule, the third uplink data packet forwarding rule, the third downlink data packet detection rule, and the third downlink data packet forwarding rule contained in the first N4 information in step 608.

[0333] In addition, the third PFCP session update request message in step 611 also includes a second uplink data packet detection rule and a second uplink data packet forwarding rule. These rules are used by the target offloading user plane network element to establish an uplink forwarding channel for service data packets offloaded from the source user plane network element, ensuring the continuity of uplink service data packets during processes where both the offloading user plane network element and the user plane network element change simultaneously. The uplink service data packets are sent from the target access network device to the target offloading user plane network element, and then forwarded by the target offloading user plane network element to the source offloading user plane network element. It is understandable that the third PFCP session update request message in step 611 and... Figure 4 In step 405, the first data packet forwarding control protocol request message sent by the intermediate session management network element to the target offloading user plane network element is the same message as the second uplink data packet detection rule in step 611. Figure 4 In step 405, the first data packet detection rule sent by the intermediate session management network element to the target offloading user plane network element is the same, and the second uplink data packet forwarding rule is the same. Figure 4 The forwarding rules for the first data packet sent by the intermediate session management network element to the target offloading user plane network element in step 405 are the same.

[0334] 612. The target user plane network element replies with a third PFCP session update response message to the intermediate session management network element. The third PFCP session update response message indicates that the PFCP session has been successfully updated.

[0335] Correspondingly, the intermediate session management network element receives the third PFCP session update response message from the target offloading user plane network element.

[0336] 613. The intermediate session management network element sends a fourth PFCP session update request message to the target user plane network element. The fourth PFCP session update request message is used to notify the target user plane network element to update the PFCP session of the terminal equipment.

[0337] Correspondingly, the target user plane network element receives the fourth PFCP session update request message from the intermediate session management network element.

[0338] The fourth PFCP session update request message in step 613 contains the second uplink data packet detection rule, the second uplink data packet forwarding rule, the second downlink data packet detection rule, and the second downlink data packet forwarding rule contained in the second N4 information in step 608.

[0339] Additionally, the fourth PFCP session update request message in step 613 also contains third indication information. For more information on the third indication information, please refer to... Figure 4 The relevant description of step 403 will not be repeated here.

[0340] For example, in cases 1.2 and 1.3 of step 608, the intermediate session management network element forwards the third instruction information to the target user plane network element; in case 1.1 of step 608, the intermediate session management network element sets the cache bit in the forwarding action information element included in the second uplink data packet forwarding rule sent to the target user plane network element to 1 according to the received second instruction information, so as to instruct the target user plane network element to cache the uplink data packet.

[0341] 614. The target user plane network element replies with the fourth PFCP session update response message to the intermediate session management network element. The fourth PFCP session update response message indicates that the PFCP session has been successfully updated.

[0342] Correspondingly, the intermediate session management network element receives the fourth PFCP session update response message from the target user plane network element.

[0343] After step 614, the downlink service data packet forwarding path is as follows:

[0344] Remote user plane network element -> Target offloaded user plane network element -> Target access network device -> Terminal device;

[0345] Target user plane network element -> Target offloading user plane network element -> Target access network device -> Terminal device.

[0346] 615. The intermediate session management network element sends a PDU session resource update request message to the target access network device. The PDU session resource update request message contains the first service data packet forwarding information from step 604.

[0347] Correspondingly, the target access network device receives the PDU session resource update request message from the intermediate session management network element.

[0348] 616. The target access network device replies with a PDU session resource update response message to the intermediate session management network element. The PDU session resource update response message indicates that the PDU session resource update was successful.

[0349] Correspondingly, the intermediate session management network element receives the PDU session resource update response message from the target access network device.

[0350] After step 616, the uplink service data packet forwarding path is as follows:

[0351] Terminal device -> Target access network device -> Target offloaded user plane network element -> Source offloaded user plane network element -> Source user plane network element;

[0352] Terminal equipment -> Target access network equipment -> Target offloading user plane network element -> Remote user plane network element.

[0353] Optionally, after step 616, this solution may also include, but is not limited to, the following steps 617-624. For details, see [link to relevant documentation]. Figure 6C , Figure 6C This is a flowchart illustrating another message transmission method provided in an embodiment of this application.

[0354] 617. The session management network element waits for the confirmation message from the target application network element.

[0355] 618. After receiving the confirmation message from the target application network element, the session management network element sends a second PDU session update message (Nsmf_PDUSession_Update request) to the intermediate session management network element. The second PDU session update message contains the fourth indication information.

[0356] Correspondingly, the target application network element sends an acknowledgment message to the session management network element.

[0357] Regarding the fourth instruction information, please refer to... Figure 4 The relevant description of step 404 will not be repeated here.

[0358] For example, the fourth instruction information can be implemented in any of the following ways:

[0359] Case 2.1: The session management network element can instruct the target user plane network element to forward uplink data packets in the message through a bit or enumeration. For example, it can use a bit in the new or existing parameters to indicate this, where setting the bit to 1 indicates that the target user plane network element forwards the uplink data packet, and setting the bit to 0 indicates that the target user plane network element does not need to forward the uplink data packet, or buffers the uplink data packet, or has no special meaning; or setting the bit to 0 indicates that the target user plane network element forwards the uplink data packet, and setting the bit to 1 indicates that the target user plane network element does not need to forward the uplink data packet, or buffers the uplink data packet, or has no special meaning; or it can use enumeration in the new or existing parameters to indicate this, using a specific enumeration value to indicate that the target user plane network element forwards the uplink data packet.

[0360] Alternatively, in case 2.2: the session management network element may also include the fifth N4 information in the message. The fifth N4 information is used to indicate the PFCP session between the intermediate session management network element and the target user plane network element. The fifth N4 information uses a bit or enumeration to instruct the target user plane network element to forward the uplink data packet. The specific indication method can refer to the indication method in case 2.1 above, and will not be elaborated here.

[0361] Alternatively, in scenario 2.3: the session management network element can include uplink packet forwarding rules in the fifth N4 information and set the forwarding bit in the forwarding action information element included in the uplink packet forwarding rules to 1 to indicate the forwarding of uplink packets. The uplink packet forwarding rules here are the second uplink packet forwarding rules in the second N4 information of step 608.

[0362] 619. The intermediate session management network element replies with a second PDU session update response message to the session management network element (Nsmf_PDUSession_Update response). The second PDU session update response message indicates that the second PDU session update was successful.

[0363] Correspondingly, the session management network element receives the second PDU session update response message from the intermediate session management network element.

[0364] 620. The intermediate session management network element sends a fifth PFCP session update request message to the target user plane network element. The fifth PFCP session update request message notifies the target user plane network element to update the PFCP session of the terminal equipment.

[0365] Correspondingly, the target user plane network element receives the fifth PFCP session update request message from the intermediate session management network element.

[0366] The fifth PFCP session update request message in step 620 contains fifth indication information, which can be found in the following reference: Figure 4The description of step 405 is omitted here. Specifically, for cases 2.2 and 2.3 in step 618, the intermediate session management network element forwards the fourth indication information to the target user plane network element; for case 2.1 in step 618, the intermediate session management network element, based on the fourth indication information, sets the forwarding bit in the forwarding action information element included in the second uplink data packet forwarding rule sent to the target user plane network element to 1 to indicate the forwarding of the uplink data packet. In other words, the intermediate session management network element sends the fifth indication information to the target user plane network element based on the fourth indication information.

[0367] 621. The target user plane network element replies with the fifth PFCP session update response message, which indicates that the PFCP session has been successfully updated.

[0368] Correspondingly, the intermediate session management network element receives the fifth PFCP session update response message from the target user plane network element.

[0369] After step 621, the uplink service data packet forwarding path is as follows:

[0370] Terminal device -> Target access network device -> Target offloading user plane network element -> Target user plane network element;

[0371] Terminal equipment -> Target access network equipment -> Target offloading user plane network element -> Remote user plane network element.

[0372] 622. If the source user plane network element does not forward service data packets within a preset time, it sends a PFCP session report to the intermediate session management network element. The PFCP session report is used to notify the intermediate session management network element of this event. That is, the PFCP session report is used to notify the source user plane network element that it has not forwarded service data packets within a preset time.

[0373] Correspondingly, the intermediate session management network element receives the PFCP session report from the source user plane network element.

[0374] 623. The intermediate session management network element, based on the PFCP session report, initiates the deletion of the originating test session and sends a PFCP session deletion message to the source user plane network element.

[0375] 624. The intermediate session management network element sends a PFCP session deletion message to the source distribution user plane network element.

[0376] As can be seen, in the above technical solution, because the target user plane network element does not forward uplink data packets before the target application network element completes the handover, but instead buffers the uplink data packets before the target application network element completes the handover, the uplink data packets are not forwarded, thus avoiding uplink data packet loss. Furthermore, because the target user plane network element only forwards the uplink data packets after the target application network element completes the handover, the uplink data packets can be forwarded to the target application network element, improving the reliability of data packet transmission. At the same time, it avoids the loss of uplink and downlink data packets at the terminal device, improving the continuity and reliability of data packet transmission.

[0377] The following example illustrates this scheme using the session management network element's determination to establish a service data packet forwarding tunnel with a user plane network element (which can refer to the target user plane network element and / or the target offloading user plane network element). For details, see [link to relevant documentation]. Figure 7A , Figure 7A This is a flowchart illustrating another message transmission method provided in an embodiment of this application. Figure 7A As shown, the method includes, but is not limited to, the following steps:

[0378] 701. The intermediate session management network element sends a first PFCP session establishment request message to the target user plane network element. The first PFCP session establishment request message is used to notify the target user plane network element to establish a PFCP session for the terminal device.

[0379] Correspondingly, the target user plane network element receives the first PFCP session establishment request message from the intermediate session management network element.

[0380] In step 701, the first PFCP session establishment request message includes a first uplink data packet detection rule and a first uplink data packet forwarding rule, as well as a first downlink data packet detection rule and a first downlink data packet forwarding rule. The first uplink data packet detection rule and the first uplink data packet forwarding rule are used by the target user plane network element to establish an uplink forwarding channel for all service data packets, and the first downlink data packet detection rule and the first downlink data packet forwarding rule are used by the target user plane network element to establish a downlink forwarding channel for all service data packets. It can be understood that uplink service data packets are received by the target user plane network element and forwarded to the data network, while downlink service data packets are received by the target user plane network element and forwarded to the target distribution user plane network element.

[0381] 702. The target user plane network element replies with the first PFCP session establishment response message to the intermediate session management network element. The first PFCP session establishment response message indicates that the PFCP session was successfully established.

[0382] Correspondingly, the intermediate session management network element receives the first PFCP session establishment response message from the target user plane network element.

[0383] In step 702, the PFCP session establishment response message contains service data packet forwarding information allocated by the target user plane network element. The service data packet forwarding information includes the tunnel endpoint identifier and the Internet Protocol address of the target user plane network element. The tunnel endpoint identifier and the Internet Protocol address of the target user plane network element are used by the intermediate session management network element to instruct the target access network device to establish an uplink service data packet forwarding channel.

[0384] 703. The intermediate session management network element sends a second PFCP session establishment request message to the target offloading user plane network element. The second PFCP session establishment request message is used to notify the target offloading user plane network element to establish a PFCP session for the terminal device.

[0385] Correspondingly, the target offloading user plane network element receives the second PFCP session establishment request message from the intermediate session management network element.

[0386] The second PFCP session establishment request message in step 703 includes a first uplink data packet detection rule, a first uplink data packet forwarding rule, a first downlink data packet detection rule, and a first downlink data packet forwarding rule. The first uplink data packet detection rule and the first uplink data packet forwarding rule are used by the target offloading user plane network element to establish an uplink forwarding channel for all service data packets, and the first downlink data packet detection rule and the first downlink data packet forwarding rule are used by the target offloading user plane network element to establish a downlink forwarding channel for all service data packets. It can be understood that uplink service data packets are sent from the target access network device to the target offloading user plane network element, and then forwarded by the target offloading user plane network element to the remote user plane network element; downlink service data packets are sent from the remote user plane network element to the target offloading user plane network element, and then forwarded by the target offloading user plane network element to the target access network device.

[0387] 704. The target user plane network element replies with a second PFCP session establishment response message to the intermediate session management network element. The second PFCP session establishment response message is used to indicate that the PFCP session has been successfully established.

[0388] Correspondingly, the intermediate session management network element receives the second PFCP session establishment response message from the target offloading user plane network element.

[0389] In step 704, the second PFCP session establishment response message includes first service data packet forwarding information, second service data packet forwarding information, and third service data packet forwarding information allocated by the target offloading user plane network element. The first, second, and third service data packet forwarding information all include the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element. The first service data packet forwarding information is used by the intermediate session management network element to instruct the target access network device to establish an uplink service data packet forwarding channel. The second service data packet forwarding information is used by the intermediate session management network element to instruct the target user plane network element / remote user plane network element to establish a downlink service data packet forwarding channel. The third service data packet forwarding information is used by the intermediate session management network element to instruct the source offloading user plane network element to establish a downlink service data packet forwarding channel to ensure the continuity of downlink service data packets.

[0390] 705. The intermediate session management network element sends a first PDU session update request (Nsmf_PDUSession_Updaterequest) to the session management network element. The first PDU session update request message contains first indication information and second service data packet forwarding information allocated by the target offloading user plane network element in step 704.

[0391] Correspondingly, the session management network element receives the first PDU session update request from the intermediate session management network element.

[0392] Regarding the first instruction information, please refer to... Figure 4 The relevant description of step 401 will not be repeated here.

[0393] in, Figure 7A The illustrated embodiment uses a session management network element to determine and establish forwarding tunnels for uplink or downlink service data packets. This ensures the continuity of uplink or downlink service data packets during processes where both user plane network elements and user plane network elements change simultaneously. It is understood that the session management network element can establish forwarding tunnels for uplink or downlink service data packets for all sessions, or for specific sessions.

[0394] 706. The session management network element replies to the intermediate session management network element with the first PDU session update response message (Nsmf_PDUSession_Updateresponse). The first PDU session update response message contains the first N4 information, the second N4 information, the third N4 information, and the fourth N4 information.

[0395] Correspondingly, the intermediate session management network element receives the first PDU session update response message from the session management network element.

[0396] The first N4 information is used to instruct the intermediate session management network element to establish a PFCP session between the intermediate session management network element and the target offloading user plane network element. The first N4 information includes a second uplink data packet detection rule, a second uplink data packet forwarding rule, a second downlink data packet detection rule, and a second downlink data packet forwarding rule. The second uplink data packet detection rule and the second uplink data packet forwarding rule are used to instruct the target offloading user plane network element to establish an uplink forwarding channel for service data packets offloaded from the target user plane network element. The second downlink data packet detection rule and the second downlink data packet forwarding rule are used to instruct the target offloading user plane network element to establish a downlink forwarding channel for service data packets offloaded from the target user plane network element. Uplink service data packets are sent from the target access network device to the target offloading user plane network element and then forwarded by the target offloading user plane network element to the target user plane network element. Downlink service data packets are sent from the target user plane network element to the target offloading user plane network element and then forwarded by the target offloading user plane network element to the target access network device. For example, for a service data packet corresponding to a service with an application identifier of 100, if it is diverted from the target user plane network element, the first N4 information contains the uplink data packet detection rules and uplink data packet forwarding rules corresponding to the service, or the first N4 information contains the downlink data packet detection rules and downlink data packet forwarding rules corresponding to the service.

[0397] In addition, the first N4 information also includes a third uplink data packet detection rule, a third uplink data packet forwarding rule, a third downlink data packet detection rule, and a third downlink data packet forwarding rule. The third uplink data packet detection rule and the third uplink data packet forwarding rule are used by the target offloading user plane network element to establish an uplink forwarding channel for service data packets offloaded from the source user plane network element. The third downlink data packet detection rule and the third downlink data packet forwarding rule are used by the target offloading user plane network element to establish a downlink forwarding channel for all service data packets, ensuring the continuity of uplink or downlink service data packets during processes where both the offloading user plane network element and the user plane network element change simultaneously. Specifically, uplink service data packets are sent from the target access network device to the target offloading user plane network element, and then forwarded by the target offloading user plane network element to the source offloading user plane network element. Downlink service data packets are sent from the source offloading user plane network element to the target offloading user plane network element, and then forwarded by the target offloading user plane network element to the target access network device. It can be understood that the third uplink data packet detection rule included in the first N4 information is related to... Figure 4 In step 405, the intermediate session management network element receives the second data packet from the session management network element under the same detection rule, and the third uplink data packet forwarding rule included in the first N4 information is the same as... Figure 4 The forwarding rules for the second data packet received by the intermediate session management network element in step 405 are the same. The third downlink data packet detection rules included in the first N4 information are the same as those in the intermediate session management network element. Figure 5In step 501, the intermediate session management network element receives the fourth data packet from the session management network element, which has the same detection rule. The third downlink data packet forwarding rule included in the first N4 information is the same as... Figure 5 In step 501, the forwarding rule for the fourth data packet received by the intermediate session management network element from the session management network element is the same. Specifically, the second data packet detection rule is the rule corresponding to the data packet detected by the target user plane network element, the second data packet forwarding rule is the rule corresponding to the data packet forwarded by the target user plane network element, and the fourth data packet detection rule is the rule corresponding to the data packet detected by the target user plane network element, and the fourth data packet forwarding rule is the rule corresponding to the data packet forwarded by the target user plane network element.

[0398] The first N4 information also includes forwarding tunnel rule indications, which indicate the rules corresponding to the packet forwarding tunnels required to be established by the third uplink packet detection rule and the third uplink packet forwarding rule to ensure the continuity of uplink service packets during the process of simultaneous changes in user plane network elements and user plane network elements. Similarly, the third downlink packet detection rule and the third downlink packet forwarding rule indicate the rules corresponding to the packet forwarding tunnels required to be established by the third downlink packet detection rule and the third downlink packet forwarding rule to ensure the continuity of downlink service packets during the process of simultaneous changes in user plane network elements and user plane network elements. It can be understood that the forwarding tunnel rule indications included in the first N4 information include the aforementioned sixth indication information and the aforementioned seventh indication information.

[0399] For example, the forwarding tunnel rule indication contained in the first N4 information can be implemented in any of the following ways:

[0400] Case 3.1: The session management network element can indicate the forwarding tunnel rule in the first PDU session update response message through a bit or enumeration. For example, it can indicate the forwarding tunnel rule through a bit in the new parameters or the original parameters, where the bit is set to 1 to indicate the forwarding tunnel rule, and the bit is set to 0 to indicate that it is not a forwarding tunnel rule or has no special meaning; or the bit is set to 0 to indicate the forwarding tunnel rule, and the bit is set to 1 to indicate that it is not a forwarding tunnel rule or has no special meaning; or it can indicate the forwarding tunnel rule through enumeration in the new parameters or the original parameters, and use a specific enumeration value to represent the forwarding tunnel rule.

[0401] Alternatively, in case 3.2: the session management network element can also indicate the forwarding tunnel rule through a bit or enumeration in the first N4 information, the third uplink data packet detection rule, the third uplink data packet forwarding rule, the third downlink data packet detection rule, or the third downlink data packet forwarding rule. The specific indication method of the forwarding tunnel rule can be referred to case 3.1, and will not be elaborated here.

[0402] The second N4 information is used to instruct the intermediate session management network element to establish a PFCP session between the intermediate session management network element and the target user plane network element. The second N4 information includes a second uplink packet detection rule, a second uplink packet forwarding rule, a second downlink packet detection rule, and a second downlink packet forwarding rule. The second uplink packet detection rule and the second uplink packet forwarding rule are used to instruct the target user plane network element to establish an uplink forwarding channel for service packets diverted from the target user plane network element. The second downlink packet detection rule and the second downlink packet forwarding rule are used to instruct the target user plane network element to establish a downlink forwarding channel for service packets diverted from the target user plane network element. It can be understood that uplink service packets are sent from the target diverted user plane network element to the target user plane network element, and then forwarded by the target user plane network element to the data network. Downlink service packets are sent from the data network to the target user plane network element, and then forwarded by the target user plane network element to the target diverted user plane network element.

[0403] Among them, the third N4 information is used to instruct the intermediate session management network element to delete the PFCP session between the intermediate session management network element and the source diversion user plane network element;

[0404] Alternatively, the third N4 information is used to instruct the updating of the PFCP session between the intermediate session management network element and the source offloading user plane network element. The third N4 information includes a first uplink packet detection rule, a first uplink packet forwarding rule, a first downlink packet detection rule, and a first downlink packet forwarding rule. The first uplink packet detection rule and the first uplink packet forwarding rule are used by the source offloading user plane network element to establish an uplink forwarding channel for service packets offloaded from the source user plane network element. The first downlink packet detection rule and the first downlink packet forwarding rule are used by the source offloading user plane network element to establish a downlink forwarding channel for all service packets, thereby ensuring the continuity of uplink or downlink service packets in a process where both the offloading user plane network element and the user plane network element change simultaneously. It can be understood that the first uplink packet detection rule included in the third N4 information and... Figure 4 In step 405, the intermediate session management network element receives the second data packet from the session management network element, which has the same detection rule. The first uplink data packet forwarding rule included in the third N4 information is the same as... Figure 4 The forwarding rule for the second data packet received by the intermediate session management network element in step 405 is the same as that in step 405. The first downlink data packet detection rule included in the third N4 information is the same as that in step 405. Figure 5 In step 501, the intermediate session management network element receives the fourth data packet from the session management network element, which has the same detection rule. The first downlink data packet forwarding rule included in the third N4 information is the same as... Figure 5In step 501, the forwarding rule for the fourth data packet received by the intermediate session management network element from the session management network element is the same. Specifically, the second data packet detection rule is the same as the rule corresponding to the data packet detected by the source-splitting user plane network element, the second data packet forwarding rule is the same as the rule corresponding to the data packet forwarded by the source-splitting user plane network element, and the fourth data packet detection rule is the same as the rule corresponding to the data packet detected by the source-splitting user plane network element, and the fourth data packet forwarding rule is the same as the rule corresponding to the data packet forwarded by the source-splitting user plane network element.

[0405] The third N4 information also includes forwarding tunnel rule indications. These indications specify the rules corresponding to the packet forwarding tunnels required to be established by the first uplink packet detection rules and the first uplink packet forwarding rules to ensure the continuity of uplink service packets during a process where both user plane network elements and user plane network elements change simultaneously. Similarly, the first downlink packet detection rules and the first downlink packet forwarding rules specify the rules corresponding to the packet forwarding tunnels required to be established by the first downlink packet detection rules and the first downlink packet forwarding rules to ensure the continuity of downlink service packets during a process where both user plane network elements and user plane network elements change simultaneously. The specific indication method for the forwarding tunnel rule indications can be referenced from the indication method in the first N4 information, and will not be elaborated upon here.

[0406] Among them, the fourth N4 information is used to instruct the intermediate session management network element to delete the PFCP session between the intermediate session management network element and the source user plane network element.

[0407] Furthermore, changes to local user plane network elements may lead to application network element switching. The session management network element can notify the source application network element of the access point identifier of the target user plane network element, so that the source application network element can trigger the application network element switching based on the access point identifier. If the application network element subscribes to the session management network element's events, it indicates that application network element confirmation is required. That is, the application network element can only send uplink data packets to the new application network element after performing the switch and sending a positive confirmation to the session management network element. In other words, when the source application network element switches to the target application network element, the target application network element can send a positive confirmation to the session management network element. Under these circumstances, the target user plane network element can send uplink data packets to the target application network element. Therefore, to implement this process, the first PDU session update response message in step 706 also includes second indication information. For more information on the second indication information, please refer to... Figure 4 The relevant description of step 402 is not repeated here.

[0408] For example, the second instruction information can be implemented in any of the following ways:

[0409] Case 4.1: The session management network element can instruct the target user plane network element to cache uplink data packets in the first PDU session update response message in step 706 through a bit or enumeration. For example, it can use a bit in the new or existing parameters to indicate this, where setting the bit to 1 indicates that the target user plane network element caches uplink data packets, and setting the bit to 0 indicates that the target user plane network element does not need to cache uplink data packets or forward uplink data packets, or has no special meaning; or setting the bit to 0 indicates that the target user plane network element caches uplink data packets, and setting the bit to 1 indicates that the target user plane network element does not need to cache uplink data packets or forward uplink data packets, or has no special meaning; or it can use enumeration in the new or existing parameters, with a specific enumeration value indicating that the target user plane network element caches uplink data packets.

[0410] Alternatively, in case 4.2: the session management network element may also instruct the target user plane network element to buffer uplink data packets in the second N4 information by using a bit or enumeration. The specific indication method can be referred to the indication method in case 1.1 above, and will not be elaborated here.

[0411] Alternatively, in case 4.3: the session management network element can set the cache bit in the forwarding action information element contained in the second uplink data packet forwarding rule contained in the second N4 information to 1 to instruct the target user plane network element to cache the uplink data packet.

[0412] Optionally, after step 706, this solution may also include, but is not limited to, the following steps 707-716. For details, please refer to... Figure 7B , Figure 7B This is a flowchart illustrating another message transmission method provided in an embodiment of this application.

[0413] 707. The intermediate session management network element sends a first PFCP session update request message to the source offloading user plane network element. The first PFCP session update request message is used to notify the source offloading user plane network element to update the PFCP session of the terminal equipment.

[0414] Correspondingly, the source-splitting user plane network element receives the first PFCP session update request message from the intermediate session management network element.

[0415] The first PFCP session update request message in step 707 includes a first uplink data packet detection rule, a first uplink data packet forwarding rule, a first downlink data packet detection rule, and a first downlink data packet forwarding rule. The first uplink data packet detection rule and the first uplink data packet forwarding rule are used by the source user plane network element to establish an uplink forwarding channel for service data packets diverted from the source user plane network element. The first downlink data packet detection rule and the first downlink data packet forwarding rule are used by the source user plane network element to establish a downlink forwarding channel for all service data packets, ensuring the continuity of uplink or downlink service data packets during processes where both the diverting user plane network element and the user plane network element change simultaneously. It can be understood that uplink service data packets are sent from the target diverting user plane network element to the source diverting user plane network element, and then forwarded from the source diverting user plane network element back to the source user plane network element. Downlink service data packets are sent from the remote user plane network element to the source diverting user plane network element, or from the source user plane network element to the source diverting user plane network element, and then forwarded from the source diverting user plane network element to the target diverting user plane network element.

[0416] In one implementation, the first uplink data packet detection rule, first uplink data packet forwarding rule, first downlink data packet detection rule, and first downlink data packet forwarding rule in step 707 are determined by the intermediate session management network element based on the forwarding tunnel rule indication in the third N4 information of step 706. The first downlink data packet detection rule and first downlink data packet forwarding rule are determined by the intermediate session management network element according to the forwarding tunnel rule indication in the third N4 information of step 706. To ensure the continuity of uplink or downlink service data packets in a process where both user plane and user plane functions change simultaneously, a data packet forwarding tunnel needs to be established. The first uplink data packet detection rule in step 707 is obtained by the intermediate session management network element by adding the tunnel endpoint identifier of the source user plane network element and the Internet Protocol address of the source user plane network element to the first uplink data packet detection rule in the third N4 information of step 706. The first uplink data packet forwarding rule in step 707 is determined by the intermediate session management network element. The intermediate session management network element obtains the first downlink data packet forwarding rule in step 707 by adding the tunnel endpoint identifier of the source user plane network element and the Internet Protocol address of the source user plane network element according to the forwarding tunnel rule instruction in the third N4 information of step 706. The first downlink data packet detection rule in step 707 is obtained by the intermediate session management network element by adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element according to the forwarding tunnel rule instruction in the third N4 information of step 706. The first downlink data packet forwarding rule in step 707 is obtained by the intermediate session management network element by adding the tunnel endpoint identifier of the target offloading user plane network element and the Internet Protocol address of the target offloading user plane network element according to the forwarding tunnel rule instruction in the third N4 information of step 706.

[0417] In another implementation, if the third N4 information is used to indicate the deletion of the PFCP session between the intermediate session management network element and the source offloading user plane network element, the intermediate session management function determines, according to the forwarding tunnel rule indication in the first N4 information in step 706, that a packet forwarding tunnel needs to be established to ensure the continuity of uplink or downlink service packets in a process where both the offloading user plane function and the user plane function change simultaneously. Then, the first uplink packet detection rule, the first uplink packet forwarding rule, the first downlink packet detection rule, and the first downlink packet forwarding rule in step 707 are generated by the intermediate session management network element.

[0418] It is understandable that the first uplink data packet detection rule in step 707 is the same as... Figure 4 The detection rule for the first data packet sent by the intermediate session management network element to the source offloading user plane network element in step 405 is the same. The first data packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the second data packet detection rule based on the sixth instruction information. The first uplink data packet forwarding rule in step 707 is the same as... Figure 4 The first data packet forwarding rule sent by the intermediate session management network element to the source user plane network element in step 405 is the same. The first data packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the source user plane network element to the second data packet forwarding rule based on the sixth instruction information. The first downlink data packet detection rule in step 707 is the same as... Figure 5 The third data packet detection rule sent by the intermediate session management network element to the source offloading user plane network element in step 501 is the same. The third data packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the fourth data packet detection rule based on the seventh instruction information. The first downlink data packet forwarding rule in step 707 is the same as... Figure 4 The forwarding rule for the third data packet sent by the intermediate session management network element to the source offloading user plane network element in step 405 is the same. The forwarding rule for the third data packet is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the target offloading user plane network element and the Internet Protocol address of the target offloading user plane network element to the fourth data packet forwarding rule according to the seventh instruction information.

[0419] 708. The source-splitting user plane network element replies with the first PFCP session update response message to the intermediate session management network element. The first PFCP session update response message indicates that the PFCP session has been successfully updated.

[0420] Correspondingly, the intermediate session management network element receives the first PFCP session update response message from the source-splitting user plane network element.

[0421] In step 708, the first PFCP session update response message contains service packet forwarding information allocated by the source offloading user plane network element. This service packet forwarding information includes the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element. This service packet forwarding information is used by the target offloading user plane network element to establish a forwarding channel for uplink service packets to ensure the continuity of uplink service packets.

[0422] 709. The intermediate session management network element sends a second PFCP session update request message to the target offloading user plane network element. The second PFCP session update request message is used to notify the target offloading user plane network element to update the PFCP session of the terminal equipment.

[0423] Correspondingly, the target user plane network element receives the second PFCP session update request message from the intermediate session management network element.

[0424] The second PFCP session update request message in step 709 contains the second uplink data packet detection rule, the second uplink data packet forwarding rule, the second downlink data packet detection rule, the second downlink data packet forwarding rule, the third uplink data packet detection rule, the third uplink data packet forwarding rule, the third downlink data packet detection rule, and the third downlink data packet forwarding rule contained in the first N4 information in step 706.

[0425] It should be noted that, based on the third uplink data packet detection rule and the third uplink data packet forwarding rule in the first N4 information in step 708, and the forwarding tunnel rule associated with the third downlink data packet detection rule and the third downlink data packet forwarding rule, the intermediate session management network element determines the third uplink data packet detection rule and the third uplink data packet forwarding rule. To ensure the continuity of uplink or downlink service data packets in a process where both user plane and user plane functions change simultaneously, a data packet forwarding tunnel needs to be established. In step 709, the third uplink data packet detection rule is obtained by the intermediate session management network element by adding the tunnel endpoint identifier of the target user plane network element and the Internet Protocol address of the target user plane network element to the third uplink data packet detection rule in the first N4 information in step 706, based on the forwarding tunnel rule indication in the first N4 information. The third uplink data packet forwarding rule in step 709... The forwarding rule in step 709 is obtained by the intermediate session management network element by adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the third uplink data packet forwarding rule in the first N4 information of step 706, as indicated by the forwarding tunnel rule in the first N4 information of step 706. The first downlink data packet detection rule in step 709 is obtained by the intermediate session management network element by adding the tunnel endpoint identifier of the target offloading user plane network element and the Internet Protocol address of the target offloading user plane network element to the first downlink data packet detection rule in the first N4 information of step 706, as indicated by the forwarding tunnel rule in the first N4 information of step 706. The first downlink data packet forwarding rule in step 709 is obtained by the intermediate session management network element by adding the tunnel endpoint identifier of the target access network device and the Internet Protocol address of the target access network device to the first downlink data packet forwarding rule in the first N4 information of step 706, as indicated by the forwarding tunnel rule in the first N4 information of step 706.

[0426] It is understandable that the third uplink data packet detection rule in step 709 is similar to... Figure 4 The first data packet detection rule sent by the intermediate session management network element to the target offloaded user plane network element in step 405 is the same. The first data packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target offloaded user plane network element to the second data packet detection rule based on the sixth instruction information. The third uplink data packet forwarding rule in step 709 is the same as... Figure 4 The forwarding rule for the first data packet sent by the intermediate session management network element to the target offloaded user plane network element in step 405 is the same. This first data packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source offloaded user plane network element and the Internet Protocol address of the source offloaded user plane network element to the second data packet forwarding rule based on the sixth instruction information. The third downlink data packet detection rule in step 707 is the same as... Figure 5The third data packet detection rule sent by the intermediate session management network element to the target offloaded user plane network element in step 501 is the same. The third data packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier and the Internet Protocol address of the target offloaded user plane network element to the fourth data packet detection rule based on the seventh instruction information. The third downlink data packet forwarding rule in step 707 is the same as... Figure 4 The third data packet forwarding rule sent by the intermediate session management network element to the target offloading user plane network element in step 405 is the same. The third data packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the target access network device and the Internet Protocol address of the target access network device to the fourth data packet forwarding rule according to the seventh instruction information.

[0427] For example, the function of the forwarding tunnel rule indication is explained below with reference to Table 3. Table 3 shows the correspondence between packet detection rules, packet forwarding rules, and forwarding tunnel rule indication.

[0428] Table 3: Correspondence between packet detection rules, packet forwarding rules, and forwarding tunnel rules.

[0429]

[0430]

[0431] As shown in Table 3, the service packet forwarding information in PDR and FAR needs to be included by the intermediate session management network element in the second uplink packet detection rule, second uplink packet forwarding rule, second downlink packet detection rule, second downlink packet forwarding rule, third uplink packet detection rule, and third downlink packet forwarding rule, and third downlink packet detection rule and third downlink packet forwarding rule sent to the source / target user plane network element. The service packet forwarding information allocated by the target user plane network element and other network elements for the packet forwarding tunnel established to ensure the continuity of uplink or downlink service packets in a process where both the user plane network element and the user plane network element change simultaneously is different from the service packet forwarding information allocated in normal service packet forwarding. The intermediate session management network element needs to distinguish between the rules for the above two situations according to the forwarding tunnel rule instructions and add the corresponding service packet forwarding information. As shown in Table 3, there is a correspondence between DL PDR 258 ​​(identifier of the third downlink data packet detection rule), the fourth service data packet forwarding information allocated by the target user plane network element, Core (source interface), N9 (source interface type), DL FAR 258 ​​(identifier of the third downlink data packet forwarding rule), the first service data packet forwarding information allocated by the target access network device, Access (target interface), N3 (target interface type), and the forwarding tunnel rule indication (Y). Because the forwarding tunnel rule indication is Y, it indicates that the third downlink data packet detection rule, the third downlink data packet forwarding rule, etc., are service data packet forwarding information allocated by the data packet forwarding tunnel established to ensure the continuity of downlink service data packets. Similarly, there is a correspondence between ULPDR 259 (identifier of the third uplink data packet detection rule), the third service data packet forwarding information allocated by the target user plane network element, Access (source interface), N3 (source interface type), UL FAR 259 (identifier of the third uplink data packet forwarding rule), the service data packet forwarding information allocated by the source user plane network element, Core (target interface), N9 (target interface type), and the forwarding tunnel rule indication (Y). Because the forwarding tunnel rule indicator is Y, it means that the forwarding information of the service data packets is allocated by the data packet forwarding tunnel established by the third uplink data packet detection rule, the third uplink data packet forwarding rule, etc., to ensure the continuity of uplink service data packets.

[0432] Furthermore, there is a correspondence between DL PDR 256 (identifier of the second downlink packet detection rule), the second service packet forwarding information allocated by the target user plane network element, Core (source interface), N9 (source interface type), DL FAR 256 (identifier of the second downlink packet forwarding rule), the second service packet forwarding information allocated by the target access network device, Access (target interface), N3 (target interface type), and forwarding tunnel rule indication (N). Because the forwarding tunnel rule indication is N, it indicates that the second downlink packet detection rule, the second downlink packet forwarding rule, etc., are service packet forwarding information allocated for normal service packet forwarding. Similarly, there is a correspondence between UL PDR 257 (identifier of the second uplink packet detection rule), the first service packet forwarding information allocated by the target user plane network element, Access (source interface), N3 (source interface type), ULFAR 257 (identifier of the second uplink packet forwarding rule), the service packet forwarding information allocated by the target user plane network element, Core (target interface), N9 (target interface type), and forwarding tunnel rule indication (N). Because the forwarding tunnel rule indicator is N, it means that the second uplink data packet detection rule, the second uplink data packet forwarding rule, etc., are service data packet forwarding information allocated for normal service data packet forwarding. 710. The target offloading user plane network element replies with the second PFCP session update response message to the intermediate session management network element. The second PFCP session update response message is used to indicate that the PFCP session has been successfully updated.

[0433] Correspondingly, the intermediate session management network element receives the second PFCP session update response message from the target offloading user plane network element.

[0434] In step 710, the second PFCP session update response message contains third and fourth service data packet forwarding information allocated by the target offloading user plane network element. Both the third and fourth service data packet forwarding information contain the tunnel endpoint identifier and the Internet Protocol address of the target offloading user plane network element. It can be understood that the third service data packet forwarding information is used by the source access network device to establish an uplink service data packet forwarding channel to ensure the continuity of uplink service data packets, and the fourth service data packet forwarding information is used by the source offloading user plane network element to establish a downlink service data packet forwarding channel to ensure the continuity of downlink service data packets.

[0435] After step 710, the downlink service data packet forwarding path is as follows:

[0436] Remote user plane network element -> Source offloading user plane network element -> Target offloading user plane network element -> Target access network device -> Terminal device;

[0437] Source user plane network element -> Source offloading user plane network element -> Target offloading user plane network element -> Target access network device -> Terminal device.

[0438] 711. The session management network element sends a third PFCP session update request message to the remote user plane network element. The third PFCP session update request message is used to notify the remote user plane network element to update the PFCP session of the terminal equipment.

[0439] Correspondingly, the remote user plane network element receives the third PFCP session update request message from the session management network element.

[0440] The third PFCP session update request message in step 711 contains the second service data packet forwarding information allocated by the target user plane network element in step 705. This information is used by the remote user plane network element to send the data packets to the target user plane network element after receiving them from the data network, based on the second service data packet forwarding information allocated by the target user plane network element.

[0441] 712. The remote user plane network element replies with a third PFCP session update response message to the session management network element. The third PFCP session update response message indicates that the PFCP session has been successfully updated.

[0442] Correspondingly, the session management network element receives the third PFCP session update response message from the remote user plane network element.

[0443] After step 712, the downlink service data packet forwarding path is as follows:

[0444] Remote user plane network element -> Target offloaded user plane network element -> Target access network device -> Terminal device;

[0445] Source user plane network element -> Source offloading user plane network element -> Target offloading user plane network element -> Target access network device -> Terminal device.

[0446] 713. The intermediate session management network element sends a fourth PFCP session update request message to the target user plane network element. The fourth PFCP session update request message is used to notify the target user plane network element to update the PFCP session of the terminal equipment.

[0447] Correspondingly, the target user plane network element receives the fourth PFCP session update request message from the intermediate session management network element.

[0448] The fourth PFCP session update request message in step 713 contains the second uplink data packet detection rule, the second uplink data packet forwarding rule, the second downlink data packet detection rule, and the second downlink data packet forwarding rule contained in the second N4 information in step 706.

[0449] The fourth PFCP session update request message in step 713 also contains third indication information. For more information on the third indication information, please refer to... Figure 4 The relevant description of step 403 will not be repeated here.

[0450] For example, in cases 1.2 and 1.3 of step 706, the intermediate session management network element forwards the third instruction information to the target user plane network element; in case 1.1 of step 706, the intermediate session management network element sets the cache bit in the forwarding action information element included in the second uplink data packet forwarding rule sent to the target user plane network element to 1 according to the received second instruction information, so as to instruct the target user plane network element to cache the uplink data packet.

[0451] 714. The target user plane network element replies with the fourth PFCP session update response message to the intermediate session management network element. The fourth PFCP session update response message indicates that the PFCP session has been successfully updated.

[0452] Correspondingly, the intermediate session management network element receives the fourth PFCP session update response message from the target user plane network element.

[0453] After step 714, the downlink service data packet forwarding path is as follows:

[0454] Remote user plane network element -> Target offloaded user plane network element -> Target access network device -> Terminal device;

[0455] Target user plane network element -> Target offloading user plane network element -> Target access network device -> Terminal device.

[0456] 715. The intermediate session management network element sends a PDU session resource update request message to the target access network device. The PDU session resource update request message contains the first service data packet forwarding information from step 704.

[0457] Correspondingly, the target access network device receives the PDU session resource update request message from the intermediate session management network element.

[0458] 716. The target access network device replies with a PDU session resource update response message to the intermediate session management network element. The PDU session resource update response message indicates that the PDU session resource update was successful.

[0459] Correspondingly, the intermediate session management network element receives the PDU session resource update response message from the target access network device.

[0460] After step 716, the uplink service data packet forwarding path is as follows:

[0461] Terminal device -> Target access network device -> Target offloaded user plane network element -> Source offloaded user plane network element -> Source user plane network element;

[0462] Terminal equipment -> Target access network equipment -> Target offloading user plane network element -> Remote user plane network element.

[0463] Optionally, after step 716, this solution may also include, but is not limited to, the following steps 717-724. For details, please refer to... Figure 7C , Figure 7C This is a flowchart illustrating another message transmission method provided in an embodiment of this application.

[0464] 717. The session management network element waits for the confirmation message from the target application network element.

[0465] 718. After receiving the confirmation message from the target application network element, the session management network element sends a second PDU session update message (Nsmf_PDUSession_Update request) to the intermediate session management network element. The second PDU session update message contains the fourth indication information.

[0466] Among them, step 718 and Figure 6C Step 618 is the same, so I will not repeat it here.

[0467] 719. The intermediate session management network element replies with a second PDU session update response message to the session management network element (Nsmf_PDUSession_Update response). The second PDU session update response message indicates that the second PDU session update was successful.

[0468] Correspondingly, the session management network element receives the second PDU session update response message from the intermediate session management network element.

[0469] 720. The intermediate session management network element sends a fifth PFCP session update request message to the target user plane network element. The fifth PFCP session update request message notifies the target user plane network element to update the PFCP session of the terminal equipment.

[0470] Among them, step 720 and Figure 6C Step 620 is the same, so I will not repeat it here.

[0471] 721. The target user plane network element replies with the fifth PFCP session update response message, which indicates that the PFCP session was successfully updated.

[0472] Correspondingly, the intermediate session management network element receives the fifth PFCP session update response message from the target user plane network element.

[0473] After step 712, the uplink service data packet forwarding path is as follows:

[0474] Terminal device -> Target access network device -> Target offloading user plane network element -> Target user plane network element;

[0475] Terminal equipment -> Target access network equipment -> Target offloading user plane network element -> Remote user plane network element.

[0476] 722. If the source user plane network element does not forward service data packets within a preset time, it sends a PFCP session report to the intermediate session management network element. The PFCP session report is used to notify the intermediate session management network element of this event. That is, the PFCP session report is used to notify the source user plane network element that it has not forwarded service data packets within a preset time.

[0477] Correspondingly, the intermediate session management network element receives the PFCP session report from the source user plane network element.

[0478] 723. The intermediate session management network element, based on the PFCP session report, initiates the deletion of the originating test session and sends a PFCP session deletion message to the source user plane network element.

[0479] 724. The intermediate session management network element sends a PFCP session deletion message to the source user plane network element.

[0480] As can be seen, in the above technical solution, because the target user plane network element does not forward uplink data packets before the target application network element completes the handover, but instead buffers the uplink data packets before the target application network element completes the handover, the uplink data packets are not forwarded, thus avoiding uplink data packet loss. Furthermore, because the target user plane network element only forwards the uplink data packets after the target application network element completes the handover, the uplink data packets can be forwarded to the target application network element, improving the reliability of data packet transmission. At the same time, it avoids the loss of uplink or downlink data packets from the terminal device, improving the continuity and reliability of data packet transmission.

[0481] This application also provides a communication system, which includes an intermediate session management network element, a session management network element, and a target user plane network element, wherein the intermediate session management network element is used to implement... Figure 4 Actions performed by the intermediate session management network element; the session management network element is used to implement... Figure 4 Actions performed by the session management network element; target user plane network element, used to implement Figure 4 The actions are performed by the target user plane network element. Secondly, the communication system also includes user plane network elements, including source offloading user plane network elements and / or target offloading user plane network elements, and intermediate session management network elements, used to implement... Figures 6A-7C Actions performed by the intermediate session management network element; the session management network element is used to implement... Figures 6A-7C Actions performed by the session management network element; target user plane network element, used to implement Figures 6A-7CActions executed by the target user plane network element; source-splitting user plane network element, used to implement Figures 6A-7C The actions performed by the source user plane network element during traffic diversion; the target user plane network element is used to implement... Figures 6A-7C The actions are performed by the target user plane network element. Additionally, the communication system includes a target access network device, a source user plane network element, and a remote user plane network element. The target access network device is used to implement... Figures 6A-7C Actions performed by the target access network device; source user plane network elements, used to implement Figures 6A-7C Actions performed by the source user plane network element; actions performed by the remote user plane network element. Figures 6A-7C Actions performed by remote user plane network elements.

[0482] This application also provides another communication system, which includes an intermediate session management network element and a user plane network element. The user plane network element includes a source offloading user plane network element and / or a target offloading user plane network element, wherein the intermediate session management network element is used to implement... Figures 5-7C Actions performed by the intermediate session management network element; source-splitting user plane network element, used to implement... Figures 5-7C The actions performed by the source user plane network element during traffic diversion; the target user plane network element is used to implement... Figures 5-7C The actions are performed by the target user plane network element. Secondly, the communication system also includes a session management network element and a target user network element. The session management network element is used to implement... Figures 6A-7C Actions performed by the session management network element; target user plane network element, used to implement Figures 6A-7C The actions are performed by the target user plane network element. Additionally, the communication system also includes a target access network device, a source user plane network element, and a remote user plane network element. The target access network device is used to implement... Figures 6A-7C Actions performed by the target access network device; source user plane network elements, used to implement Figures 6A-7C Actions performed by the source user plane network element; actions performed by the remote user plane network element. Figures 6A-7C Actions performed by remote user plane network elements.

[0483] The above mainly describes the solution provided in this application from the perspective of interaction between various network elements. It is understood that, in order to achieve the above functions, each network element includes corresponding hardware structures and / or software modules for executing each function. Those skilled in the art should readily recognize that, based on the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0484] This application embodiment can divide the intermediate session management network element, user plane network element (such as source offloading user plane network element, target offloading user plane network element, target user plane network element, etc.), and session management network element into functional modules according to the above method examples. For example, each function can be divided into a separate functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. It should be noted that the module division in this application embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0485] In the case of using integrated units, see Figure 8 , Figure 8 This is a schematic diagram of a communication device provided in an embodiment of this application. The communication device 800 can be applied to the above-described... Figures 4-7C In the method shown, such as Figure 8 As shown, the communication device 800 includes a transceiver module 801. The transceiver module 801 can be a transceiver or a communication interface. This communication device can be used to implement intermediate session management network elements, user plane network elements (such as source-shunting user plane network elements, target-shunting user plane network elements, target user plane network elements, etc.) or session management network elements involved in any of the above method embodiments, or to implement the functions of network elements involved in any of the above method embodiments. The network element or network function can be a network component in a hardware device, a software function running on dedicated hardware, or a virtualization function instantiated on a platform (e.g., a cloud platform). Optionally, the communication device 800 may further include a processing module 802 and a storage module 803. The processing module 802 can be one or more processors, and the processing module 802 can be used to support the communication device 800 in performing the processing actions in the above method embodiments. The storage module 803 is used to store the program code and data of the communication device 800.

[0486] In one example, when the communication device acts as an intermediate session management network element or is a chip applied within an intermediate session management network element, and executes the steps performed by the intermediate session management network element in the above method embodiments, the transceiver module 801 supports communication with the session management network element, user plane network elements (such as source offloading user plane network element, target offloading user plane network element, target user plane network element, etc.), etc. The transceiver module specifically performs... Figures 4-7C The sending and / or receiving actions performed by the intermediate session management network element, such as supporting the intermediate session management network element to perform one or more steps in steps 401 and 403, and / or other processes used in the techniques described herein.

[0487] In one example, when the communication device functions as a session management network element or is a chip applied within a session management network element, it executes the steps performed by the session management network element in the above method embodiments. The transceiver module 801 supports communication with intermediate session management network elements, etc., and specifically performs... Figures 4-7C The sending and / or receiving actions performed by the session management network element, such as supporting the session management network element to perform one or more steps in steps 402 and 404, and / or other processes used in the techniques described herein.

[0488] In one example, when the communication device acts as a source-splitting user plane network element or is a chip applied in a source-splitting user plane network element, it executes the steps performed by the source-splitting user plane network element in the above method embodiments. The transceiver module 801 is used to support communication with intermediate session management network elements, etc., and the transceiver module specifically performs… Figures 4-7C The transmission and / or reception actions performed by the source-splitting user plane network element, such as supporting the source-splitting user plane network element to perform one or more steps in steps 604 and 616, and / or other processes used in the techniques described herein.

[0489] In one example, when the communication device acts as a target offloaded user plane network element or is a chip applied in a target offloaded user plane network element, it executes the steps performed by the target offloaded user plane network element in the above method embodiments. The transceiver module 801 is used to support communication with intermediate session management network elements, etc., and the transceiver module specifically performs… Figures 4-7C The sending and / or receiving actions performed by the target offloading user plane network element, such as supporting the target offloading user plane network element to perform one or more steps in steps 602 and 610, and / or other processes used in the techniques described herein.

[0490] In one example, when the communication device acts as a target user plane network element or is a chip applied in a target user plane network element, and performs the steps executed by the target user plane network element in the above method embodiments, the transceiver module 801 is used to support communication with intermediate session management network elements, etc., and the transceiver module specifically performs...Figures 4-7C The sending and / or receiving actions performed by the target user plane network element, such as other processes that support the target user plane network element in performing the techniques described herein.

[0491] In one possible implementation, when the intermediate session management network element, source offloading user plane network element, target offloading user plane network element, target user plane network element, or session management network element is a chip, the transceiver module 801 can be an interface, pin, or circuit, etc. The interface can be used to input data to be processed to the processor and can output the processor's processing results. In a specific implementation, the interface can be a general purpose input / output (GPIO) interface, which can connect to multiple peripheral devices (such as displays (LCDs), cameras, radio frequency (RF) modules, antennas, etc.). The interface is connected to the processor via a bus. Of course, the interface can also be understood as a communication interface.

[0492] The processing module 802 may be a processor that can execute computer execution instructions stored in the storage module to cause the chip to perform the methods involved in the above embodiments.

[0493] Furthermore, a processor may include a controller, an arithmetic logic unit (ALU), and registers. For example, the controller is primarily responsible for instruction decoding and issuing control signals for the operations corresponding to the instructions. The ALU is primarily responsible for performing fixed-point or floating-point arithmetic operations, shift operations, and logical operations, and can also perform address operations and translations. Registers are primarily responsible for storing register operands and intermediate operation results temporarily stored during instruction execution. In specific implementations, the processor's hardware architecture can be an application-specific integrated circuit (ASIC) architecture, a microprocessor without interlocked piped stages (MIPS) architecture, an advanced reduced instruction set machine (RISC) machine (ARM) architecture, or a network processor (NP) architecture, etc. The processor can be single-core or multi-core.

[0494] The storage module 803 can be an internal storage module of the chip, such as a register or cache. Alternatively, the storage module 803 can be an external storage module, such as a ROM or other types of static storage devices that can store static information and instructions, such as RAM.

[0495] It should be noted that the functions of the processor and interface can be implemented through hardware design, software design, or a combination of both; no restrictions are imposed here.

[0496] This application embodiment also provides a communication device, including a processor, a memory, an input interface, and an output interface. The input interface is used to receive information from other communication devices outside the communication device, and the output interface is used to output information to other communication devices outside the communication device. The processor calls a computer program stored in the memory to implement... Figures 4-8 Any of the embodiments shown.

[0497] This application embodiment also provides a computer-readable storage medium storing a computer program, which, when executed, implements... Figures 4-8 Any of the embodiments shown.

[0498] This application embodiment also provides a chip, which includes at least one processor and an interface. The processor is used to read and execute instructions stored in a memory. When the instructions are executed, the chip causes the chip to perform actions such as... Figures 4-8 Any of the embodiments shown.

[0499] This application also provides a computer program product containing instructions that, when executed on a computer, causes... Figures 4-8 Any of the embodiments shown is performed.

[0500] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the objectives of the embodiments of this application, depending on actual needs. Furthermore, the network element units in the various embodiments of this application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The integrated units described above can be implemented in hardware or as software network element units.

[0501] If the integrated units described above are implemented as software network elements and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the essential contribution of the technical solution of this application, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, cloud server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks. The above descriptions are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the scope of the technology disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for transmitting instruction information, characterized in that, The method is applied to an intermediate session management network element, and the method includes: Send a first indication message to the session management network element. The first indication message is used to indicate that the intermediate session management network element has inserted the target offloading user plane network element and the target user plane network element, and has deleted the source offloading user plane network element and the source user plane network element. Receive a second indication information from the session management network element, the second indication information being used to instruct the target user plane network element to buffer uplink data packets; According to the second instruction information, a third instruction information is sent to the target user plane network element, the third instruction information being used to instruct the target user plane network element to buffer uplink data packets; The fourth indication information is received from the session management network element, and the fourth indication information is used to instruct the target user plane network element to forward the uplink data packet; Based on the fourth instruction information, a fifth instruction information is sent to the target user plane network element, the fifth instruction information being used to instruct the target user plane network element to forward the uplink data packet.

2. The method according to claim 1, characterized in that, The method further includes: Send a first data packet forwarding control protocol request message to the user plane network element. The first data packet forwarding control protocol request message includes a first data packet detection rule and a first data packet forwarding rule. If the user plane network element is the source offloading user plane network element, the first data packet detection rule is the rule corresponding to the data packet detected by the source offloading user plane network element from the target offloading user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packet forwarded by the source offloading user plane network element from the target offloading user plane network element to the source user plane network element. If the user plane network element is the target offloading user plane network element, the first data packet detection rule is the rule corresponding to the data packets from the target access network device detected by the target offloading user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packets from the target access network device forwarded by the target offloading user plane network element to the source offloading user plane network element.

3. The method according to claim 2, characterized in that, The method further includes: The second data packet detection rule, the second data packet forwarding rule, and the sixth indication information are received from the session management network element; the sixth indication information is used to indicate one or more of the following: the second data packet detection rule is the rule corresponding to the data packet detected by the source diversion user plane network element or the target diversion user plane network element; the second data packet forwarding rule is the rule corresponding to the data packet forwarded by the source diversion user plane network element or the target diversion user plane network element.

4. The method according to claim 3, characterized in that, If the user plane network element is the target offloading user plane network element, the first packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the target offloading user plane network element and the Internet Protocol address of the target offloading user plane network element to the second packet detection rule according to the sixth indication information. The first packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the second packet forwarding rule according to the sixth indication information. If the user plane network element is the source offloading user plane network element, the first packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the second packet detection rule according to the sixth indication information. The first packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source user plane network element and the Internet Protocol address of the source user plane network element to the second packet forwarding rule according to the sixth indication information.

5. A method for transmitting instruction information, characterized in that, The method is applied to a session management network element, and the method includes: The intermediate session management network element receives a first indication message, which indicates that the intermediate session management network element has inserted the target offloading user plane network element and the target user plane network element, and has deleted the source offloading user plane network element and the source user plane network element. The second instruction information is sent to the intermediate session management network element according to the first instruction information, and the second instruction information is used to instruct the target user plane network element to buffer uplink data packets; A fourth indication message is sent to the intermediate session management network element. The fourth indication message is used to instruct the target user plane network element to forward the uplink data packet. The fourth indication message is sent by the session management network element after it learns that the target application network element has completed the handover.

6. The method according to claim 5, characterized in that, The method further includes: Send a second data packet detection rule, a second data packet forwarding rule, and a sixth indication information to the intermediate session management network element; the sixth indication information is used to indicate one or more of the following: the second data packet detection rule is the rule corresponding to the data packet detected by the source diversion user plane network element or the target diversion user plane network element, and the second data packet forwarding rule is the rule corresponding to the data packet forwarded by the source diversion user plane network element or the target diversion user plane network element.

7. A method for transmitting instruction information, characterized in that, The method is applied to user plane network elements, and the method includes: Receive third indication information from the intermediate session management network element, the third indication information being used to instruct the user plane network element to buffer uplink data packets; The fifth instruction information is received from the intermediate session management network element, which is used to instruct the user plane network element to forward the uplink data packet.

8. The method according to claim 7, characterized in that, The method further includes: The intermediate session management network element receives a first data packet forwarding control protocol request message, which includes a first data packet detection rule and a first data packet forwarding rule. If the user plane network element is a source-splitting user plane network element, the first data packet detection rule is the rule corresponding to the data packet detected by the source-splitting user plane network element from the target-splitting user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packet forwarded by the source-splitting user plane network element from the target-splitting user plane network element to the source user plane network element. If the user plane network element is the target offloading user plane network element, the first data packet detection rule is the rule corresponding to the data packets from the target access network device detected by the target offloading user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packets from the target access network device forwarded by the target offloading user plane network element to the source offloading user plane network element.

9. The method according to claim 8, characterized in that, If the user plane network element is the target offloading user plane network element, the first packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the target offloading user plane network element and the Internet Protocol address of the target offloading user plane network element to the second packet detection rule according to the sixth instruction information. The first packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the second packet forwarding rule according to the sixth instruction information. If the user plane network element is the source offloading user plane network element, the first packet detection rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source offloading user plane network element and the Internet Protocol address of the source offloading user plane network element to the second packet detection rule according to the sixth indication information; the first packet forwarding rule is obtained by the intermediate session management network element adding the tunnel endpoint identifier of the source user plane network element and the Internet Protocol address of the source user plane network element to the second packet forwarding rule according to the sixth indication information. The sixth indication information is used to indicate one or more of the following: the second data packet detection rule is the rule corresponding to the data packet detection of the source diversion user plane network element or the target diversion user plane network element; the second data packet forwarding rule is the rule corresponding to the data packet forwarding of the source diversion user plane network element or the target diversion user plane network element.

10. A method for transmitting indication information, characterized in that, The method includes: The intermediate session management network element sends a first indication message to the session management network element. The first indication message is used to indicate that the intermediate session management network element has inserted the target offloading user plane network element and the target user plane network element, and has deleted the source offloading user plane network element and the source user plane network element. The session management network element sends a second instruction to the intermediate session management network element according to the first instruction information. The second instruction information is used to instruct the target user plane network element to buffer uplink data packets. The target user plane network element receives third indication information from the intermediate session management network element. The third indication information is sent by the intermediate session management network element according to the second indication information. The third indication information is used to instruct the target user plane network element to buffer uplink data packets. The session management network element sends a fourth indication information to the intermediate session management network element. The fourth indication information is used to instruct the target user plane network element to forward the uplink data packet. The fourth indication information is the indication information sent by the session management network element after it learns that the target application network element has completed the handover. The intermediate session management network element sends a fifth instruction to the target user plane network element according to the fourth instruction information. The fifth instruction information is used to instruct the target user plane network element to forward the uplink data packet.

11. An intermediate session management network element, characterized in that, The intermediate session management network element includes a transceiver module, which is used for: Send a first indication message to the session management network element. The first indication message is used to indicate that the intermediate session management network element has inserted the target offloading user plane network element and the target user plane network element, and has deleted the source offloading user plane network element and the source user plane network element. Receive a second indication information from the session management network element, the second indication information being used to instruct the target user plane network element to buffer uplink data packets; According to the second instruction information, a third instruction information is sent to the target user plane network element, the third instruction information being used to instruct the target user plane network element to buffer uplink data packets; The fourth indication information is received from the session management network element, and the fourth indication information is used to instruct the target user plane network element to forward the uplink data packet; Based on the fourth instruction information, a fifth instruction information is sent to the target user plane network element, the fifth instruction information being used to instruct the target user plane network element to forward the uplink data packet.

12. A session management network element, characterized in that, The session management network element includes a transceiver module. The transceiver module is used to receive first indication information from the intermediate session management network element. The first indication information is used to indicate that the intermediate session management network element has inserted the target offloading user plane network element and the target user plane network element, and has deleted the source offloading user plane network element and the source user plane network element. The second instruction information is sent to the intermediate session management network element according to the first instruction information, and the second instruction information is used to instruct the target user plane network element to buffer uplink data packets; A fourth indication message is sent to the intermediate session management network element. The fourth indication message is used to instruct the target user plane network element to forward the uplink data packet. The fourth indication message is sent by the session management network element after it learns that the target application network element has completed the handover.

13. A user plane network element, characterized in that, The user plane network element includes a transceiver module. The transceiver module is used to receive a first data packet forwarding control protocol request message from an intermediate session management network element. The first data packet forwarding control protocol request message includes a first data packet detection rule and a first data packet forwarding rule. If the user plane network element is a source-splitting user plane network element, the first data packet detection rule is the rule corresponding to the data packet detected by the source-splitting user plane network element from the target-splitting user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packet forwarded by the source-splitting user plane network element from the target-splitting user plane network element to the source user plane network element. If the user plane network element is the target offloading user plane network element, the first data packet detection rule is the rule corresponding to the data packets from the target access network device detected by the target offloading user plane network element, and the first data packet forwarding rule is the rule corresponding to the data packets from the target access network device forwarded by the target offloading user plane network element to the source offloading user plane network element.

14. A communication device, characterized in that, It includes a processor that invokes a computer program stored in memory to implement the method as claimed in any one of claims 1-10.

15. A computer-readable storage medium, characterized in that, A computer-readable storage medium stores a computer program that, when executed, implements the method as claimed in any one of claims 1-10.

16. A chip, characterized in that, The chip includes at least one processor and an interface, the processor being configured to read and execute instructions stored in a memory, wherein when the instructions are executed, the chip causes the chip to perform the method as described in any one of claims 1-10.

17. A computer program product comprising instructions that, when executed on a computer, causes the method of any one of claims 1-10 to be performed.

18. A communication system, characterized in that, The communication system includes an intermediate session management network element, a session management network element, and a user plane network element. The intermediate session management network element is used to perform the method of any one of claims 1-4, the session management network element is used to perform the method of any one of claims 5-6, and the user plane network element is used to perform the method of any one of claims 7-9.

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