Message forwarding method, device and system

Abstract

The embodiments of the present application provide a message forwarding method, device and system, which relate to the field of communication technology and can improve the technical problem of more signaling interactions and longer switching delay when the existing session management network element modifies the PDU session. The method includes: the session management network element sends a path identifier to the first device; wherein the first device includes the access network element corresponding to the PDU session and the user plane network element corresponding to the PDU session; the PDU session corresponds to the first terminal; the path identifier is used to indicate the first path from the access network element to the user plane network element; the first path includes part or all of the second path, and the second path is the path corresponding to the PDU session established in advance by the session management network element for the second terminal; the session management network element also sends the identification information of the destination address corresponding to the path identifier to the first device; so that the first device carries the path identifier corresponding to the destination address in the data according to the destination address of the received data, and forwards it through the path corresponding to the destination address.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a message forwarding method, device and system. Background Art

[0002] In the 3rd Generation Partnership Project (3GPP) communication system, a session management element (NE) can establish a protocol data unit (PDU) session for a terminal, allowing the terminal to send data to the user plane NE via the access network element based on the PDU session. Since the terminal can be mobile during communication, when the terminal switches from the original access network element to the target access network element, the NE can modify the PDU session corresponding to the terminal, allowing the terminal to send data to the user plane NE via the target access network element based on the modified PDU session.

[0003] Among them, when the terminal switches from the original access network element to the target access network element, the target access network element can send a path switching request including the terminal identifier to the session management element through the mobility management element. The session management element determines the PDU session corresponding to the terminal based on the terminal identifier, and determines whether the user plane network element corresponding to the PDU session can continue to serve the terminal. If not, the session management element can determine an intermediate user plane network element for the terminal, and send the tunnel information of the intermediate user plane network element to the user plane network element and the target access network element respectively, and send the tunnel information of the user plane network element and the tunnel information of the target access network element to the intermediate user plane network element to establish an N3 tunnel between the target access network element and the intermediate user plane network element, and establish an N9 tunnel between the intermediate user plane network element and the user plane network element, thereby completing the PDU session modification.

[0004] When modifying the PDU session, the above-mentioned session management network element needs to exchange tunnel information multiple times between the target access network element corresponding to the switched path and each user plane network element to establish a session tunnel, resulting in large signaling overhead and long switching delay. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a message forwarding method, device and system that can improve the technical problems of large signaling overhead and long switching delay when the existing session management network element modifies the PDU session.

[0006] In the first aspect, an embodiment of the present application provides a message forwarding method, which includes: a session management network element sends a path identifier to a first device; wherein the first device includes an access network network element corresponding to the PDU session and a user plane network element corresponding to the PDU session; the PDU session corresponds to a first terminal; the path identifier is used to indicate a first path from the access network element to the user plane network element; the first path includes part or all of the second path, and the second path is the path corresponding to the PDU session established in advance by the session management network element for the second terminal; the session management network element sends identification information of the destination address corresponding to the path identifier to the first device; so that the first device carries the path identifier corresponding to the destination address in the data according to the destination address of the received data, and forwards it through the path corresponding to the destination address.

[0007] Based on the first aspect, when the first path includes part or all of the second path, the session management network element can send a path identifier to the access network element or user plane network element, eliminating the need to re-establish the portion of the first path that is identical to the second path, thereby reducing signaling overhead and shortening handover latency. Furthermore, the session management network element can also send the correspondence between the path identifier and the destination address to the first device, so that after receiving the data, the first device determines the path for forwarding the data based on the destination address of the data and sends the data to the next-hop network element, carrying the path identifier corresponding to the path.

[0008] In one possible design, the first path is the first GTP-U path; the second path is the second GTP-U path.

[0009] Based on this possible design, the session management network element sends the path identifier to the first device, so that the first device can carry the path identifier in the GTP-U packet header of the data and send it to the next-hop network element when performing data transmission.

[0010] In one possible design, the first path includes an intermediate user plane network element.

[0011] In one possible design, the path identifier includes a first path identifier and a second path identifier; wherein the first path identifier is used to indicate the path from the access network element to the intermediate user plane network element; and the second path identifier is used to indicate the path from the intermediate user plane network element to the user plane network element.

[0012] Based on the two possible designs described above, when an intermediate user plane network element exists, the session management network element can send a path identifier to the intermediate user plane network element, so that the intermediate user plane network element forwards data based on the path identifier. Furthermore, compared to the intermediate user plane network element establishing different forwarding entries based on the different destination addresses of the terminal data corresponding to different PDU sessions, in the embodiment of the present application, the intermediate user plane network element can directly establish a forwarding entry corresponding to the path identifier based on the path identifier, thereby reducing the number of forwarding entries on the intermediate user plane network element and lowering the overhead of the intermediate user plane network element.

[0013] In one possible design, the session management network element sends path information corresponding to the path identifier to the first device; wherein the path information includes identification information of the access network element corresponding to the first path and identification information of the user plane network element.

[0014] Based on this possible design, the session management network element sends the path information to the first device, so that the first device can determine the access network element and user plane network element corresponding to the first path according to the path information, so that the first device can determine the next-hop network element according to the path information when forwarding data.

[0015] In one possible design, the path information includes tunnel information of the user plane network element and / or tunnel information of the access network element.

[0016] Based on this possible design, when the path information includes tunnel information of the user plane network element and / or tunnel information of the access network element, the user plane network element and the access network element can establish a communication connection based on each other's tunnel information, facilitating subsequent data transmission.

[0017] In a second aspect, a communication device is provided. The communication device can implement the functions performed by the session management network element in the above-mentioned first aspect or the possible design of the first aspect, and the functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-mentioned functions. For example, a sending module. The sending module is used to send a path identifier to a first device; wherein the first device includes an access network network element corresponding to a PDU session and a user plane network element corresponding to the PDU session; the PDU session corresponds to a first terminal; the path identifier is used to indicate a first path from the access network network element to the user plane network element; the first path includes part or all of the second path, and the second path is the path corresponding to the PDU session established in advance by the session management network element for the second terminal. The sending network element is also used to send identification information of the destination address corresponding to the path identifier to the first device; so that the first device carries the path identifier corresponding to the destination address in the data according to the destination address of the received data, and forwards it through the path corresponding to the destination address.

[0018] The specific implementation of the communication device may refer to the behavior and function of the session management network element in the message forwarding method provided in the first aspect or any possible design of the first aspect. Based on the communication device described in the second aspect, when the first path includes part or all of the second path, the session management network element may send a path identifier to the access network element or the user plane network element, without re-establishing the portion of the first path that is identical to the second path, thereby reducing signaling overhead and shortening handover latency. In addition, the session management network element may also send the correspondence between the path identifier and the destination address to the first device, so that after receiving the data, the first device determines the path for forwarding the data based on the destination address of the data, and sends the path identifier corresponding to the path to the next-hop network element in the data.

[0019] In one possible design, the first path is the first GTP-U path; the second path is the second GTP-U path.

[0020] Based on this possible design, the session management network element sends the path identifier to the first device, so that the first device can carry the path identifier in the GTP-U packet header of the data and send it to the next-hop network element when performing data transmission.

[0021] In one possible design, the first path includes an intermediate user plane network element.

[0022] In one possible design, the path identifier includes a first path identifier and a second path identifier; wherein the first path identifier is used to indicate the path from the access network element to the intermediate user plane network element; and the second path identifier is used to indicate the path from the intermediate user plane network element to the user plane network element.

[0023] Based on the two possible designs described above, when an intermediate user plane network element exists, the session management network element can send a path identifier to the intermediate user plane network element, so that the intermediate user plane network element forwards data based on the path identifier. Furthermore, compared to the intermediate user plane network element establishing different forwarding entries based on the different destination addresses of the terminal data corresponding to different PDU sessions, in the embodiment of the present application, the intermediate user plane network element can directly establish a forwarding entry corresponding to the path identifier based on the path identifier, thereby reducing the number of forwarding entries on the intermediate user plane network element and lowering the overhead of the intermediate user plane network element.

[0024] In one possible design, the sending module is also used to send path information corresponding to the path identifier to the first device; wherein the path information includes identification information of the access network element and the user plane network element corresponding to the first path.

[0025] Based on this possible design, the session management network element sends the path information to the first device, so that the first device can determine the access network element and user plane network element corresponding to the first path according to the path information, so that the first device can determine the next-hop network element according to the path information when forwarding data.

[0026] In one possible design, the path information includes tunnel information of the user plane network element and / or tunnel information of the access network element.

[0027] Based on this possible design, when the path information includes tunnel information of the user plane network element and / or tunnel information of the access network element, the user plane network element and the access network element can establish a communication connection based on each other's tunnel information, facilitating subsequent data transmission.

[0028] According to a third aspect, a communication device is provided. The communication device may be a session management network element ("SME") or a chip or system-on-chip ("SoC") within the SME. The communication device may implement the functions performed by the SME in each of the above aspects or possible designs, and the functions may be implemented in hardware. In one possible design, the communication device may include a transceiver. The transceiver may be configured to support the communication device in implementing the functions described in the first aspect or any of the possible designs of the first aspect. For example, the transceiver may be configured to send a path identifier to a first device; wherein the first device includes an access network element corresponding to a PDU session and a user plane network element corresponding to the PDU session; the PDU session corresponds to a first terminal; the path identifier indicates a first path from the access network element to the user plane network element; the first path includes part or all of a second path; the second path is a path corresponding to the PDU session pre-established by the SME for the second terminal; and the transceiver may be configured to send identification information of a destination address corresponding to the path identifier to the first device, so that the first device, based on the destination address of the received data, carries the path identifier corresponding to the destination address in the data and forwards the data via the path corresponding to the destination address. In another possible design, the communication device may further include a memory for storing computer-executable instructions and data necessary for the communication device. When the communication device is running, the transceiver executes the computer-executable instructions stored in the memory to cause the communication device to perform the message forwarding method described in the first aspect or any possible design of the first aspect.

[0029] Among them, the specific implementation method of the communication device can refer to the behavior function of the session management network element in the message forwarding method provided by the first aspect or any possible design of the first aspect.

[0030] In a fourth aspect, a communication device is provided, which includes one or more processors and one or more memories; the one or more memories are coupled to the one or more processors, and the one or more memories are used to store computer program code or computer instructions; when the one or more processors execute the computer instructions, the communication device executes the message forwarding method described in the first aspect or any possible design of the first aspect.

[0031] In a fifth aspect, a computer-readable storage medium is provided, which stores computer instructions or programs. When the computer instructions or programs are run on a computer, the computer executes the message forwarding method described in the first aspect or any possible design of the first aspect.

[0032] In a sixth aspect, a computer program product comprising instructions is provided, which, when executed on a computer, enables the computer to execute the message forwarding method as described in the first aspect or any possible design of the first aspect.

[0033] In the seventh aspect, a chip system is provided, which includes one or more processors and one or more memories; the one or more memories are coupled to the one or more processors, and the one or more memories store computer program codes or computer instructions; when the one or more processors execute the computer program codes or computer instructions, the chip system executes the message forwarding method described in the first aspect or any possible design of the first aspect.

[0034] Among them, the technical effects brought about by any design method in the third to seventh aspects can refer to the technical effects brought about by any possible design in the first to second aspects mentioned above, and will not be repeated here.

[0035] In an eighth aspect, an embodiment of the present application provides a message forwarding method, the method comprising: a first device receives a path identifier from a session management network element; wherein the first device includes an access network network element corresponding to a protocol data unit PDU session and a user plane network element corresponding to the PDU session; the PDU session corresponds to a first terminal; the path identifier is used to indicate a first path from the access network element to the user plane network element; the first path includes part or all of the second path, and the second path is the path corresponding to the PDU session established in advance by the session management network element for the second terminal; the first device receives identification information of the destination address corresponding to the path identifier from the session management network element; the first device obtains data including the destination address of the first terminal; the first device carries the path identifier corresponding to the destination address in the data according to the destination address of the data, and forwards it through the path corresponding to the destination address.

[0036] Based on the eighth aspect, when the first path includes part or all of the second path, the first device can receive a path identifier from the session management network element, eliminating the need to re-establish the portion of the first path that is identical to the second path, thereby reducing signaling overhead and shortening handover latency. Furthermore, by receiving the correspondence between the path identifier and the destination address, the first device can determine, after receiving data, the path for forwarding the data based on the data's destination address and send the path identifier corresponding to the path to the next-hop network element along with the data.

[0037] In one possible design, the first path is the first GTP-U path; the second path is the second GTP-U path.

[0038] Based on this possible design, the first device can carry the path identifier in the GTP-U packet header of the data and send it to the next-hop network element when transmitting data.

[0039] In one possible design, the first path includes an intermediate user plane network element.

[0040] In one possible design, the path identifier includes a first path identifier and a second path identifier; wherein the first path identifier is used to indicate the path from the access network element to the intermediate user plane network element; and the second path identifier is used to indicate the path from the intermediate user plane network element to the user plane network element.

[0041] Based on the two possible designs described above, when an intermediate user plane network element exists, the intermediate user plane network element can forward data based on the path identifier. Compared to the intermediate user plane network element establishing different forwarding entries based on the different destination addresses of the terminal data corresponding to different PDU sessions, in the embodiment of the present application, the intermediate user plane network element can directly establish a forwarding entry corresponding to the path identifier based on the path identifier, thereby reducing the forwarding entries on the intermediate user plane network element and reducing the overhead of the intermediate user plane network element.

[0042] In one possible design, the first device receives path information corresponding to the path identifier from the session management network element; wherein the path information includes identification information of the access network element corresponding to the first path and identification information of the user plane network element.

[0043] Based on this possible design, the first device can determine the access network element and user plane network element corresponding to the first path according to the path information, so that when the first device forwards data, it can determine the next hop network element according to the path information.

[0044] In one possible design, the path information includes tunnel information of the user plane network element and / or tunnel information of the access network element.

[0045] Based on this possible design, when the path information includes tunnel information of the user plane network element and / or tunnel information of the access network element, the user plane network element and the access network element can establish a communication connection based on each other's tunnel information, facilitating subsequent data transmission.

[0046] In a ninth aspect, a communication device is provided. The communication device can implement the functions performed by the first device in the eighth aspect or the possible design of the eighth aspect. The functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. For example, a receiving module and a sending module. The receiving module is configured to receive a path identifier from a session management network element. The first device includes an access network element corresponding to a protocol data unit (PDU) session and a user plane network element corresponding to the PDU session. The PDU session corresponds to a first terminal. The path identifier is used to indicate a first path from the access network element to the user plane network element. The first path includes part or all of a second path. The second path is a path corresponding to the PDU session pre-established by the session management network element for the second terminal. The receiving module is further configured to receive identification information of a destination address corresponding to the path identifier from the session management network element. The receiving module is further configured to obtain data including the destination address from the first terminal. The sending module is configured to carry the path identifier corresponding to the destination address in the data based on the destination address of the data and forward the data via the path corresponding to the destination address.

[0047] The specific implementation of the communication device may refer to the behavior function of the first device in the message forwarding method provided in the eighth aspect or any possible design of the eighth aspect. Based on the communication device described in the ninth aspect, when the first path includes part or all of the second path, the first device can receive a path identifier from the session management network element without re-establishing the portion of the first path that is identical to the second path, thereby reducing signaling overhead and shortening switching latency. In addition, by receiving a correspondence between the path identifier and the destination address, the first device can determine the path for forwarding the data based on the destination address of the data after receiving the data, and carry the path identifier corresponding to the path in the data and send it to the next-hop network element.

[0048] In one possible design, the first path is the first GTP-U path; the second path is the second GTP-U path.

[0049] Based on this possible design, the first device can carry the path identifier in the GTP-U packet header of the data and send it to the next-hop network element when transmitting data.

[0050] In one possible design, the first path includes an intermediate user plane network element.

[0051] In one possible design, the path identifier includes a first path identifier and a second path identifier; wherein the first path identifier is used to indicate the path from the access network element to the intermediate user plane network element; and the second path identifier is used to indicate the path from the intermediate user plane network element to the user plane network element.

[0052] Based on the two possible designs described above, when an intermediate user plane network element exists, the intermediate user plane network element can forward data based on the path identifier. Compared to the intermediate user plane network element establishing different forwarding entries based on the different destination addresses of the terminal data corresponding to different PDU sessions, in the embodiment of the present application, the intermediate user plane network element can directly establish a forwarding entry corresponding to the path identifier based on the path identifier, thereby reducing the forwarding entries on the intermediate user plane network element and reducing the overhead of the intermediate user plane network element.

[0053] In one possible design, the receiving module is also used to receive path information corresponding to the path identifier from the session management network element; wherein the path information includes identification information of the access network element corresponding to the first path and identification information of the user plane network element.

[0054] Based on this possible design, the first device can determine the access network element and user plane network element corresponding to the first path according to the path information, so that when the first device forwards data, it can determine the next hop network element according to the path information.

[0055] In one possible design, the path information includes tunnel information of the user plane network element and / or tunnel information of the access network element.

[0056] Based on this possible design, when the path information includes tunnel information of the user plane network element and / or tunnel information of the access network element, the user plane network element and the access network element can establish a communication connection based on each other's tunnel information, facilitating subsequent data transmission.

[0057] In a tenth aspect, a communication device is provided. The communication device may be a first device or a chip or system-on-chip in the first device. The communication device may implement the functions performed by the first device in the above-mentioned aspects or possible designs, and the functions may be implemented through hardware. In one possible design, the communication device may include: a transceiver. The transceiver may be used to support the communication device in implementing the functions involved in the above-mentioned eighth aspect or any possible design of the eighth aspect. For example, the transceiver may be configured to receive a path identifier from a session management network element; wherein the first device includes an access network element corresponding to a protocol data unit (PDU) session and a user plane network element corresponding to the PDU session; the PDU session corresponds to a first terminal; the path identifier is used to indicate a first path from the access network element to the user plane network element; the first path includes part or all of a second path, the second path being the path corresponding to the PDU session established in advance by the session management network element for the second terminal; the transceiver may also be configured to receive identification information of a destination address corresponding to the path identifier from the session management network element; the transceiver may also be configured to obtain data including a destination address from the first terminal; the transceiver may also be configured to carry the path identifier corresponding to the destination address in the data based on the destination address of the data, and forward the data through the path corresponding to the destination address. In another possible design, the communication device may further include a memory configured to store computer-executable instructions and data necessary for the communication device. When the communication device is running, the transceiver executes the computer-executable instructions stored in the memory, so that the communication device performs the message forwarding method as described in the eighth aspect or any possible design of the eighth aspect.

[0058] Among them, the specific implementation method of the communication device can refer to the behavioral function of the first device in the message forwarding method provided by the eighth aspect or any possible design of the eighth aspect.

[0059] In the eleventh aspect, a communication device is provided, which includes one or more processors and one or more memories; the one or more memories are coupled to the one or more processors, and the one or more memories are used to store computer program code or computer instructions; when the one or more processors execute the computer instructions, the communication device executes the message forwarding method described in the eighth aspect or any possible design of the eighth aspect.

[0060] In the twelfth aspect, a computer-readable storage medium is provided, which stores computer instructions or programs. When the computer instructions or programs are run on a computer, the computer executes the message forwarding method described in the eighth aspect or any possible design of the eighth aspect.

[0061] In the thirteenth aspect, a computer program product comprising instructions is provided, which, when executed on a computer, enables the computer to execute the message forwarding method as described in the eighth aspect or any possible design of the eighth aspect.

[0062] In the fourteenth aspect, a chip system is provided, which includes one or more processors and one or more memories; the one or more memories are coupled to the one or more processors, and the one or more memories store computer program codes or computer instructions; when the one or more processors execute the computer program codes or computer instructions, the chip system executes the message forwarding method described in the eighth aspect or any possible design of the eighth aspect.

[0063] Among them, the technical effects brought about by any design method in the tenth to fourteenth aspects can refer to the technical effects brought about by any possible design in the eighth to ninth aspects mentioned above, and will not be repeated here.

[0064] In a fifteenth aspect, a communication system is provided, which includes the communication device as described in any one of the second to third aspects and the communication device as described in any one of the eighth to ninth aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 A simplified schematic diagram of a communication system provided in an embodiment of the present application;

[0066] Figure 1a A simplified schematic diagram of a 5G communication system provided in an embodiment of the present application;

[0067] Figure 2 A schematic diagram of the structure of a communication device provided in an embodiment of the present application;

[0068] Figure 3 A flowchart of a message forwarding method provided in an embodiment of the present application;

[0069] Figure 4 A simplified schematic diagram of a communication system provided in an embodiment of the present application;

[0070] Figure 5 A schematic diagram of the composition of a communication device provided in an embodiment of the present application;

[0071] Figure 6 A schematic diagram of the composition of a communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0072] Before describing the embodiments of the present application, the technical terms involved in the embodiments of the present application are described.

[0073] A protocol data unit (PDU) session is a transmission path (or tunnel) used to transmit data to a terminal. A PDU session may include a transmission path from a data network to a core network element (such as a user plane element) and then to an access network element, as well as air interface resources allocated by the access network element for sending data to a specific terminal. After the access network element receives the data transmitted on the PDU session, it may send the data to the terminal corresponding to the PDU session via point-to-point (PTP) unicast on the air interface. A PDU session is oriented towards one terminal. The PDU session is at the user equipment (UE) level, and one terminal corresponds to one or more PDU sessions.

[0074] The specific process of the session management network element establishing a PDU session for the terminal includes:

[0075] Step 101: A terminal sends a session establishment request to a mobility management network element through an access network element. Correspondingly, the mobility management network element receives the session establishment request.

[0076] The session establishment request is used to request the establishment of a PDU session corresponding to the terminal.

[0077] Optionally, the terminal further sends identification information of the PDU session to the mobility management network element through the access network element, wherein the identification information of the PDU session is used to identify the PDU session.

[0078] Optionally, the session establishment request and the identification information of the PDU session are carried in a non-access stratum message (NAS message) and sent to the mobility management network element.

[0079] Optionally, the terminal further sends the location information of the terminal to the mobility management network element through the access network element.

[0080] Step 102: The mobility management network element sends a create session context request message to the session management network element. Correspondingly, the session management network element receives the create session context request message.

[0081] The create session context request message may include identification information of the terminal, identification information of the PDU session, and a session establishment request.

[0082] Optionally, the create session context request message also includes location information of the terminal.

[0083] Step 103: The session management network element sends a policy creation request to the policy control network element. Correspondingly, the policy control network element receives the policy creation request.

[0084] The policy creation request may include identification information of the terminal and identification information of the PDU session.

[0085] Step 104: The policy control network element sends a policy creation request response to the session management network element. Correspondingly, the session management network element receives the policy creation request response.

[0086] The policy creation request response may include identification information of the service corresponding to the terminal, QoS parameters or priority corresponding to the service, etc. QoS parameters may include bandwidth, delay, etc.

[0087] Step 105: The session management network element sends an N4 session establishment request to the user plane network element. Correspondingly, the user plane network element receives the N4 session establishment request.

[0088] Optionally, the session management network element determines a user plane network element corresponding to the PDU session for the terminal according to the location information of the terminal.

[0089] Step 106: The user plane network element sends an N4 session establishment request response to the session management network element. Correspondingly, the session management network element receives the N4 session establishment request response.

[0090] The N4 session establishment request response includes tunnel information of the user plane network element.

[0091] Step 107: The session management network element sends an N1N2 information transfer message to the mobility management network element. Correspondingly, the mobility management network element receives the N1N2 information transfer message.

[0092] The N1N2 information transfer message is Namf_Communication_N1N2Message Transfer, which may include a session identifier, tunnel information of a user plane network element, and session establishment acceptance information; the session establishment acceptance information is used to indicate acceptance of a session establishment request sent by the terminal.

[0093] Step 108: The mobility management network element sends an N2 session request (N2 request) to the access network element. Correspondingly, the access network element receives the N2 session request.

[0094] The N2 session request may include identification information of the PDU session, tunnel information of the user plane network element, and session establishment acceptance information.

[0095] Step 109: The access network element sends a wireless connection establishment request to the terminal. Correspondingly, the terminal receives the wireless connection establishment request.

[0096] The access network element may allocate air interface resources for the PDU session corresponding to the terminal according to the N2 session request.

[0097] Optionally, the wireless connection establishment request may include session establishment acceptance information.

[0098] Step 110: The access network element sends the tunnel information of the access network element to the session management element via the mobility management element. Correspondingly, the session management element receives the tunnel information of the access network element.

[0099] Step 111: The session management network element sends an N4 session modification request to the user plane network element. Correspondingly, the user plane network element receives the N4 session modification request.

[0100] The N4 session modification request may include tunnel information of the access network element.

[0101] The session management NE sends the tunnel information of the access network element to the user plane NE, and sends the tunnel information of the user plane NE to the access network element, so as to facilitate the establishment of a session tunnel between the access network element and the user plane NE and complete the PDU session establishment process.

[0102] When a terminal moves from a source access network element to a target access network element, the session management element can modify the terminal's corresponding PDU session so that the terminal can send data to the user plane element through the target access network element based on the modified PDU session. However, when the session management element modifies the terminal's PDU session, it must repeatedly exchange tunnel information between the access network element corresponding to the post-handover path and each user plane element to establish the session tunnel, resulting in high signaling overhead and long handover latency.

[0103] To address this issue, embodiments of the present application provide a message forwarding method, in which a session management network element can send a path identifier to an access network element or a user plane network element, causing the access network element or the user plane network element to send data from a first terminal to a next-hop network element via a first path based on the path identifier. Compared to establishing a session tunnel by repeatedly exchanging tunnel information between the access network element and each user plane network element corresponding to the switched path, in embodiments of the present application, when the first path includes part or all of the second path, the session management network element can send the path identifier to the access network element or the user plane network element, eliminating the need to re-establish the portion of the first path that is identical to the second path, thereby reducing signaling overhead and handover latency. Furthermore, when intermediate user plane network elements are present, compared to establishing different forwarding entries based on the different destination addresses of terminal data corresponding to different PDU sessions, in embodiments of the present application, the intermediate user plane network element can directly establish a forwarding entry corresponding to the path identifier based on the path identifier, thereby reducing forwarding entries on the intermediate user plane network elements and lowering their overhead.

[0104] The following describes in detail the implementation of the embodiments of the present application in conjunction with the accompanying drawings.

[0105] The message forwarding method provided in the embodiment of the present application can be used in any communication system, which can be a third generation partnership project (3GPP) communication system, for example, a long term evolution (LTE) system, or a fifth generation (5G) mobile communication system, a new radio (NR) system, an NR V2X system and other next-generation communication systems, or a non-3GPP communication system without limitation.

[0106] The message forwarding method provided in the embodiment of the present application can be applied to various communication scenarios, for example, it can be applied to one or more of the following communication scenarios: enhanced mobile broadband (eMBB), ultra reliable low latency communication (URLLC), machine type communication (MTC), massive machine type communication (mMTC), device to device (D2D), vehicle to everything (V2X), vehicle to vehicle (V2V), and Internet of Things (IoT). Figure 1 Taking the example, the message forwarding method provided in the embodiment of the present application is described.

[0107] Figure 1 A schematic diagram of a communication system provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the communication system may include at least one terminal, at least one access network element, a mobility management network element, a session management network element, a policy control network element, a user plane network element and a data network (DN).

[0108] in, Figure 1The terminal can be located within the cell coverage of the access network element. The terminal can communicate with the access network element over the air interface via the uplink (UL). In the UL direction, the terminal sends data to the access network element, which forwards the received data to the core network element. The core network element processes the data and sends the processed data to the application server via the N6 interface. In the DL direction, the application server sends downlink data to the core network element, which processes the data and sends the processed data to the access network element via the N3 interface. The access network element processes the data and sends it to the terminal over the air interface. For example, the terminal sends uplink data to the access network element through the uplink physical sidelink share channel (PUSCH) in the UL direction. The access network element forwards the received uplink data to the core network element. The core network element processes the uplink data and sends the processed uplink data to the application server through the N6 interface. The access network element that forwards the uplink data from the terminal to the core network element and the access network element that forwards the downlink data from the core network element to the terminal may be the same access network element or different access network elements.

[0109] The terminal can also communicate with the core network element through a specific interface. For example, the terminal can communicate with the mobility management element in the core network element through the N1 interface.

[0110] The session management network element can establish a PDU session for the terminal after the terminal accesses the network. The terminal accesses the external data network DN through the PDU session and interacts with the application server deployed in the DN, such as Figure 1 As shown, depending on the DN accessed by the terminal, the network can select the anchor point of the user plane PDU session accessing the DN according to the network policy, that is, the protocol data unit anchor (PSA), and access the application server through the N6 interface of the PSA. The application server of the same application can be deployed in multiple locations. The network can select a PSA that is close to the user device and can support the user device to access the DN based on the access location of the user device, so as to reduce routing detours and reduce network latency.

[0111] in, Figure 1 The terminal in the term "terminal" can be referred to as user equipment (UE), mobile station (MS), or mobile terminal (MT). Figure 1The terminal in the term "terminal" can be a mobile phone, tablet computer, or computer with wireless transceiver capabilities. It can also include virtual reality (VR) terminals, augmented reality (AR) terminals, wireless terminals used in industrial control, wireless terminals used in autonomous driving, wireless terminals used in telemedicine, wireless terminals used in smart grids, wireless terminals used in smart cities, wireless terminals used in smart homes, in-vehicle terminals, vehicles with vehicle-to-vehicle (V2V) communication capabilities, intelligent connected vehicles, drones with UAV-to-UAV (U2U) communication capabilities, and so on, without limitation.

[0112] Figure 1 The access network element in the 5G-AN / 5G-RAN network can be any device with wireless transceiver functions, which is mainly used to implement wireless physical control functions, resource scheduling and wireless resource management, wireless access control and mobility management functions. Specifically, the access network element can be a device that supports wired access or a device that supports wireless access. Exemplarily, the access network element can be an access network (AN) / radio access network (RAN) device, which is composed of multiple 5G-AN / 5G-RAN nodes. The 5G-AN / 5G-RAN node can be: an access point (AP), a base station (nodeB, NB), an enhanced base station (enhance nodeB, eNB), a next generation base station (NR nodeB, gNB), a transmission reception point (TRP), a transmission point (TP) or some other access node.

[0113] Figure 1 The mobility management network element is mainly responsible for user equipment access authentication, mobility management, signaling interaction between various functional network elements, etc., such as: managing user registration status, user connection status, user registration and network entry, tracking area update, cell switching user authentication and key security.

[0114] Figure 1The session management network element in the NET can be referred to as a session management function, a multicast / broadcast-service management function (MB-SMF), or a multicast session management network element, etc., without limitation. The session management network element is primarily used to implement user plane transmission logical channels, such as session management functions such as establishing, releasing, and modifying protocol data unit (PDU) sessions.

[0115] Figure 1 The policy control network element in can be used to provide policies to the mobility management network element and the session management network element, such as quality of service policies and the like.

[0116] Figure 1 The user plane network element in the DN can be called a PDU session anchor (PSA), a user plane function, or a multicast / broadcast user plane function (MB-UPF). The user plane network element serves as the anchor point for the user plane transmission logical channel and is primarily responsible for routing and forwarding user plane data. For example, it establishes a channel with the terminal (i.e., the user plane transmission logical channel), forwards data packets between the terminal and the DN on this channel, and is responsible for filtering terminal data packets, forwarding data, rate control, and generating billing information. The multicast / broadcast (MB) service controller (MB service controller) has service management functions such as group management, security management, and service announcements.

[0117] Figure 1 The data network DN in the data network may be a carrier network that provides data transmission services to users, such as a carrier network that provides IP Multimedia Services (IMS). An application server (AS) may be deployed in the DN to provide data transmission services to users.

[0118] It should be noted that the terminal, access network element and core network element in the embodiments of the present application can be one or more chips, or a system on chip (SOC), etc. Figure 1 The figures are merely exemplary and the number of devices included is not limited. Figure 1 In addition to the devices shown, the communication system may also include other devices. Figure 1 The names of each device and each link in the Figure 1 In addition to the names shown, each device and each link can also be named with other names. Figure 1 In addition to the network elements shown, Figure 1 The network shown can also include application function network elements, network slice selection network elements, network warehouse network elements, authentication service network elements, network storage network elements, network data analysis network elements, network open network elements, etc., without restriction.

[0119] Specifically, Figure 1 The communication system shown may be a communication system in the 3rd Generation Partnership Project (3GPP), for example, a long term evolution (LTE) communication system, or a fourth generation (4G) communication system, or a fifth generation (5G) communication system or a new radio (NR) communication system, or a non-3GPP communication system, without limitation.

[0120] by Figure 1 The communication system shown is a 5G communication system as an example. Figure 1aAs shown, the network element or entity corresponding to the above-mentioned access network element may be a radio access network (RAN) in a 5G communication system, the network element or entity corresponding to the mobility management network element may be an access and mobility management function (AMF) in a 5G communication system, the network element or entity corresponding to the session management network element may be a session management function (SMF) in a 5G communication system, the policy control network element may be a policy control function (PCF) in a 5G communication system, the network element or entity corresponding to the user plane network element may be a user plane function (UPF) in a 5G communication system, the network element or entity corresponding to the application function network element may be an application function (AF) in a 5G communication system, the network element or entity corresponding to the network slice selection network element may be a network slice selection function (NSSF) in a 5G communication system, the network element or entity corresponding to the network repository network element may be a network repository function (NRF) in a 5G communication system, and the network element or entity corresponding to the authentication service network element may be an authentication service function (Authentication Server) in a 5G communication system. function, AUSF), the network element or entity corresponding to the network storage network element can be the NRF or unified data repository (UDR) or unified data management (UDM) in the 5G communication system, the network element or entity corresponding to the network data analysis network element can be the network data analysis function (NWDAF) in the 5G communication system, the network element or entity corresponding to the network exposure network element can be the network exposure function (NEF) in the 5G communication system, and the network element or entity corresponding to the service control network element can be the service control point (SCP) in the 5G communication system, etc.

[0121] Among them, Figure 1aAs shown, the terminal communicates with the AMF through the next generation network (N) 1 interface (abbreviated as N1), the RAN device communicates with the AMF through the N2 interface (abbreviated as N2), the RAN device communicates with the UPF through the N3 interface (abbreviated as N3), and the UPF communicates with the application server in the DN through the N6 interface. Core network elements can communicate with each other through service-based interfaces, such as: AMF can communicate with other core network elements through the Namf interface, SMF can communicate with other core network elements through the Nsmf interface, PCF can communicate with other core network elements through the Npcf interface, NSSF can communicate with other core network elements through the Nnssf interface, NEF can communicate with other core network elements through the Nnef interface, NRF can communicate with other core network elements through the Nnrf interface, UDM can communicate with other core network elements through the Nudr interface, NWDAF can communicate with other core network elements through the Nnwdaf interface, and AUSF can communicate with other core network elements through the Nausf interface.

[0122] When implementing it specifically, Figure 1 As shown, for example, each terminal, access network element and core network element can adopt Figure 2 The structure shown, or including Figure 2 Parts shown. Figure 2 This is a schematic diagram of the composition of a communication device 200 provided in an embodiment of the present application. The communication device 200 can be a terminal or a chip or system on chip in a terminal; it can also be an access network element or a chip or system on chip in an access network element; it can also be a core network element or a chip or system on chip in a core network element. Figure 2 As shown, the communication device 200 includes a processor 201 , a transceiver 202 and a communication line 203 .

[0123] Furthermore, the communication device 200 may further include a memory 204 , wherein the processor 201 , the memory 204 and the transceiver 202 may be connected via a communication line 203 .

[0124] The processor 201 is a central processing unit (CPU), a general-purpose processor, a network processor (NP), a digital signal processor (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The processor 201 may also be other devices with processing functions, such as circuits, devices, or software modules, without limitation.

[0125] Transceiver 202 is used to communicate with other devices or other communication networks. The other communication networks may be Ethernet, radio access networks (RAN), wireless local area networks (WLAN), etc. Transceiver 202 may be a module, circuit, transceiver, or any device capable of communication.

[0126] The communication line 203 is used to transmit information between the components included in the communication device 200.

[0127] The memory 204 is used to store instructions, where the instructions may be computer programs.

[0128] The memory 204 may be a read-only memory (ROM) or other type of static storage device that can store static information and / or instructions, or a random access memory (RAM) or other type of dynamic storage device that can store information and / or instructions, or 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 compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), magnetic disk storage media or other magnetic storage devices, etc., without limitation.

[0129] It should be noted that memory 204 can exist independently of processor 201 or can be integrated with processor 201. Memory 204 can be used to store instructions, program code, or data. Memory 204 can be located within or outside of communication device 200, without limitation. Processor 201 is configured to execute instructions stored in memory 204 to implement the message forwarding method provided in the following embodiments of this application.

[0130] In one example, the processor 201 may include one or more CPUs, such as Figure 2 CPU0 and CPU1 in.

[0131] As an optional implementation, the communication device 200 includes multiple processors, for example, Figure 2 In addition to the processor 201, a processor 207 may also be included.

[0132] As an optional implementation, the communication apparatus 200 further includes an output device 205 and an input device 206. For example, the input device 206 is a keyboard, a mouse, a microphone, a joystick, or the like, and the output device 205 is a display screen, a speaker, or the like.

[0133] It should be noted that the communication device 200 can be a desktop computer, a portable computer, a network server, a mobile phone, a tablet computer, a wireless terminal, an embedded device, a chip system or a computer with a plurality of CPUs. Figure 2 In addition, Figure 3 The structure shown in the figure does not constitute a limitation on the communication device, except Figure 2 In addition to the components shown, the communication device may include more or fewer components than shown, or combine certain components, or arrange the components differently.

[0134] In the embodiment of the present application, the chip system can be composed of chips, or can include chips and other discrete devices.

[0135] In addition, the actions and terms involved in the various embodiments of this application can refer to each other without limitation. The message names or parameter names in the messages exchanged between the various devices in the embodiments of this application are only examples, and other names can also be used in specific implementations without limitation.

[0136] The following combination Figure 1 The communication system shown in the figure describes the message forwarding method provided in the embodiment of the present application, wherein the first terminal can be any terminal in the communication system, the session management network element can be any session management network element in the communication system, the mobility management network element can be any mobility management network element in the communication system, and the user plane network element can be any user plane network element in the communication system. The first terminal, session management network element, mobility management network element, target access network element, and user plane network element described in the following embodiments can all have Figure 2 Parts shown.

[0137] Figure 3 A flowchart of a message forwarding method provided in an embodiment of the present application is shown as follows: Figure 3 As shown, the method may include:

[0138] Step 301: A session management network element establishes a PDU session for a first terminal.

[0139] Specifically, when the first terminal accesses the network through the source access network element, the session management network element can refer to the above steps 101 to 111 to establish a PDU session for the first terminal, so that when the first terminal transmits data, it sends data to the user plane network element through the source access network element according to the PDU session.

[0140] Exemplarily, the first terminal can communicate with an application server in a data network based on a PDU session. The first terminal can send data with a destination address of the application server to a user plane network element based on the PDU session. The user plane network element sends the data to the application server corresponding to the destination address according to the destination address of the data. The first terminal can also communicate with other terminals in the communication system based on the PDU session. Taking the communication between the first terminal and the third terminal as an example, assuming that the PDU session established by the session management network element for the first terminal corresponds to the first user plane network element, and the PDU session established for the third terminal corresponds to the third user plane network element, the first terminal can send data with a destination address of the third terminal to the first user plane network element based on the PDU session. The first user plane network element forwards the data to the third user plane network element. The third user plane network element forwards the data to the third terminal through the PDU session corresponding to the third terminal.

[0141] Step 302: The first terminal switches from a source access network element to a target access network element.

[0142] Specifically, when the first terminal continues to move during the communication process, causing the first terminal to switch from the source access network network element to the target access network network element, the source access network network element can send the identification information of the first terminal and the identification information of the PDU session corresponding to the first terminal to the target access network network element.

[0143] It should be noted that the process of the first terminal switching from the source access network element to the target access network element can refer to the description of the terminal switching between different access network elements in the prior art, and will not be described in detail.

[0144] Step 303: The target access network element sends a first request to the session management element through the mobility management element.

[0145] The first request may include identification information of the target access network element corresponding to the first terminal and identification information of the PDU session corresponding to the first terminal.

[0146] Specifically, the target access network network element can send a first request to the session management network element through the mobility management network element to inform the session management network element that the first terminal has switched to the target access network network element and the PDU session of the first terminal needs to be modified so that the first terminal can send data to the user plane network element through the target access network element according to the modified PDU session.

[0147] Optionally, the target access network element carries the first request in an N2 path switching request and sends it to the mobility management network element. After receiving the first request, the mobility management network element carries the first request in a PDU session modification request and sends it to the session management network element.

[0148] Optionally, the target access network network element further sends the location information of the first terminal to the session management network element through the mobility management network element.

[0149] Step 304: The session management network element determines a path identifier according to the first request.

[0150] The path identifier indicates a first path from the target access network element to the user plane element corresponding to the PDU session. The first path includes part or all of the second path. The second path is the path corresponding to the PDU session pre-established by the session management element for the second terminal. The second path is the path from the access network element corresponding to the PDU session of the second terminal to the user plane element corresponding to the PDU session of the second terminal. The second terminal can be any terminal in the communication system other than the first terminal.

[0151] Specifically, the session management network element may determine the first path according to the first request, and determine the first path identifier according to the first path.

[0152] Exemplarily, the session management network element may determine, based on the first request, whether the user-plane network element can continue to provide the PDU session service for the first terminal. If so, the first path is determined to include the target access network element and the user-plane network element. If not, an intermediate user-plane network element is determined for the first terminal. The intermediate user-plane network element is configured to forward data of the first terminal from the target access network element to the user-plane network element. In this case, the first path is determined to include the target access network element, the intermediate user-plane network element, and the user-plane network element.

[0153] Optionally, the session management network element determines an intermediate user plane network element for the first terminal according to the location information of the first terminal.

[0154] For example, refer to Figure 4 Taking the case where UE1 switches from RAN1 to RAN2 and the user plane network element corresponding to the PDU session established by the session management network element SMF for UE1 is UPF1 as an example, SMF can determine whether UPF1 can continue to provide PDU session services for UE1 based on the location information of the first terminal. If so, it is determined that the first path includes RAN2 and UPF1. If not, SMF can determine the intermediate UPF for UE1 based on the location information of UE1. Assuming that the intermediate UPF determined by SMF for UE1 is UPF2, it is determined that the first path includes RAN2, UPF2 and UPF1.

[0155] Illustratively, the session management network element may determine, based on the determined first path, whether the first path includes part or all of the second path, and determine the path identifier of the first path based on the determination result.

[0156] In one possible design, the session management network element determines, based on the first path, that the first path includes the entire path of the second path. The session management network element then determines the path identifier of the first path based on the path identifier of the second path. The fact that the first path includes the entire path of the second path can be understood as meaning that the first path and the second path are identical, or can also be understood as meaning that a portion of the first path and the second path are identical.

[0157] Specifically, when the first path is the same as the second path, the session management network element may determine the path identifier of the second path as the path identifier of the first path.

[0158] The first path and the second path being the same may mean that the first path and the second path share the same network element, or may be described as each network element corresponding to the first path being the same as each network element corresponding to the second path.

[0159] For example, refer to Figure 4 Taking the second path corresponding to the PDU session established by the session management network element SMF for UE2 as an example, including RAN2 and UPF1, assuming that SMF determines that the first path corresponding to UE1 includes RAN2 and UPF1, then it is determined that the first path is the same as the second path, and the path identifier of the second path is determined as the path identifier of the first path.

[0160] For example, refer to Figure 4 Taking the second path corresponding to the PDU session established by SMF for UE2 as an example, including RAN2, UPF2 and UPF1, assuming that SMF determines that the first path corresponding to UE1 includes RAN2, UPF2 and UPF1, then it is determined that the first path is the same as the second path, and the path identifier of the second path is determined as the path identifier of the first path.

[0161] Specifically, when a portion of the first path is the same as the second path, the session management network element may use the path identifier of the second path as the first path identifier of the portion of the first path. At the same time, the session management network element may also set a second path identifier for another portion of the first path, and use the first path identifier and the second path identifier as the path identifier of the first path.

[0162] The fact that a portion of the first path is identical to the second path can mean that the portion of the first path and the second path share the same network element. Alternatively, it can be described as the target access network element corresponding to the first path and the access network element corresponding to the second path being the same access network element, and the intermediate user plane network element corresponding to the first path and the user plane network element corresponding to the second path being the same user plane network element. In this case, the session management network element can use the identification information of the second path as the first path identifier of the path between the target access network element and the intermediate user plane network element in the first path. The session management network element can also establish a communication connection between the intermediate user plane network element and the user plane network element, set a second path identifier for the path between the intermediate user plane network element and the user plane network element, and use the first path identifier and the second path identifier as the path identifier of the first path.

[0163] For example, refer to Figure 4 Taking the second path corresponding to the PDU session established by the session management network element SMF for UE2 as an example, including RAN2 and UPF2, assuming that SMF determines that the first path corresponding to UE1 includes RAN2, UPF2 and UPF1, it can be determined that the path identifier of the first path includes two parts, one part is the first path identifier determined according to the path identifier of the second path, and the other part is the second path identifier set by the session management network element for the path between UPF2 and UPF1.

[0164] It should be noted that when the session management network element establishes a communication connection between the intermediate user plane network element and the user plane network element, the identification information of the device can be exchanged between the intermediate user plane network element and the user plane network element to establish a communication connection between the intermediate user plane network element and the user plane network element based on the device layer. For example, the session management network element can send the identification information of the intermediate user plane network element to the user plane network element, and send the identification information of the user plane network element to the intermediate user plane network element to establish a communication connection between the intermediate user plane network element and the user plane network element. The identification information of the device may include the media access control (MAC) address of the device, the internet protocol (IP) address of the device, the identity (ID) information of the device, and other information used to identify the device.

[0165] In another possible design, the session management network element determines, based on the first path, that the first path includes a portion of the second path. The session management network element then determines the path identifier of the first path based on the path identifier of the second path. The first path including the portion of the second path can be understood as meaning that the first path and the portion of the second path are identical, or can also be understood as meaning that the portion of the first path and the portion of the second path are identical.

[0166] Specifically, when the first path and the second path have a partial path that is identical, the session management network element may determine the path identifier of the partial path in the path identifier of the second path that is identical to the first path as the path identifier of the first path.

[0167] The first path and the second path having a partial path being the same may mean that the first path and the partial path of the second path share the same network element, or may be described as each network element corresponding to the first path being the same as each network element corresponding to the partial path of the second path.

[0168] For example, refer to Figure 4 Taking the second path corresponding to the PDU session established by the session management network element SMF for UE2 as an example, including RAN2, UPF2 and UPF1, assuming that the SMF determines that the first path corresponding to UE1 includes RAN2 and UPF2, then it is determined that the first path is the same as the path between RAN2 and UPF2 in the second path, and the path identifier corresponding to the path between RAN2 and UPF2 in the path identifier of the second path is determined as the path identifier of the first path.

[0169] Specifically, when a portion of the first path is identical to a portion of the second path, the session management network element may use the path identifier of the portion of the second path that is identical to the portion of the first path as the first path identifier of the first path. At the same time, the session management network element may also set a second path identifier for another portion of the first path, and use the first path identifier and the second path identifier as the path identifier of the first path.

[0170] Among them, the fact that part of the path of the first path is the same as part of the path of the second path can mean that part of the path of the first path and part of the path of the second path share the same network element, or it can be described as that the network elements corresponding to the part of the path of the first path are the same as the network elements corresponding to the part of the path of the second path.

[0171] For example, refer to Figure 4 Taking the example of a second path corresponding to a PDU session established by the session management network element (SMF) for UE2, which includes RAN2, UPF2, and UPF1, and assuming that the SMF determines that the first path corresponding to UE1 includes RAN2, UPF2, and UPF3, the SMF determines that the path between RAN2 and UPF2 in the first path is the same as the path between RAN2 and UPF2 in the second path. The path identifier corresponding to the path between RAN2 and UPF2 in the path identifier of the second path is determined as the first path identifier of the first path. The session management network element may also establish a communication connection between UPF2 and UPF3, set a second path identifier, and use the first path identifier and the second path identifier as the path identifiers of the first path.

[0172] It should be noted that the process of the session management network element establishing a communication connection for UPF2 and UPF3 can refer to the process of the session management network element establishing a communication connection between the intermediate user plane network element and the user plane network element, and will not be repeated here.

[0173] For another example, taking the example of a second path corresponding to a PDU session established by the session management network element (SMF) for UE2, which includes RAN2, UPF2, and UPF1, and assuming that the SMF determines that the first path corresponding to UE1 includes RAN3, UPF2, and UPF1, the SMF determines that the path between UPF2 and UPF1 in the first path is the same as the path between UPF2 and UPF1 in the second path, and determines the path identifier corresponding to the path between UPF2 and UPF1 in the path identifier of the second path as the first path identifier of the first path. The session management network element may also establish a communication connection between RAN3 and UPF2, set a second path identifier, and use the first path identifier and the second path identifier as the path identifiers of the first path.

[0174] It should be noted that the specific process of the session management network element establishing the communication connection between RAN3 and UPF2 can refer to the above steps 105 to 111 and will not be described in detail.

[0175] In another possible design, the session management network element determines, based on the first path, that the first path does not include part or all of the second path. The session management network element then establishes the first path for the first terminal and sets a path identifier for the first path.

[0176] Among them, when the session management network element establishes the first path for the first terminal, the specific process of establishing the communication connection between the target access network network element and the user plane network element, or the specific process of establishing the communication connection between the target access network element and the intermediate user plane network element can refer to the above-mentioned steps 105 to 111, and will not be repeated here. The communication connection between the intermediate user plane network and the user plane network element can be established by referring to the process of establishing the communication connection between the intermediate user plane network element and the user plane network element by the above-mentioned session management network element, and will not be repeated here.

[0177] Step 305: The session management network element sends the path identifier and identification information of the destination address corresponding to the path identifier to the target access network element through the mobility management network element.

[0178] The session management network element sends the path identifier to the target access network network element via the mobility management network element, so that after receiving the data from the first terminal, the target access network network element sends the data to the user plane network element via the first path corresponding to the path identifier. The session management network element also sends identification information of the destination address corresponding to the path identifier to the target access network network element, so that after receiving the data from the first terminal, the target access network network element parses the data from the first terminal, obtains the destination address of the data, and determines a path for forwarding the data based on the destination address of the data.

[0179] Optionally, the session management network element further sends path information corresponding to the path identifier to the target access network element; wherein the path information includes identification information of the access network element and identification information of the user plane network element corresponding to the first path. When the first path includes an intermediate user plane network element, the path information also includes identification information of the intermediate user plane network element.

[0180] Optionally, the above step 305 also includes the following step 305a.

[0181] Alternatively, the above step 305 may be replaced by the following step 305a.

[0182] It should be noted that when the above step 305 includes the following step 305a, the following step 306 may be executed; when the above step 305 is replaced by the following step 305a, the following steps 307 to 309 may be executed.

[0183] Step 305a: The session management network element sends the path identifier and identification information of the destination address corresponding to the path identifier to the user plane network element corresponding to the first path.

[0184] Specifically, the session management network element sends the identification information of the destination address corresponding to the path identifier to the user plane network element, so that after receiving the data from the first terminal, the user plane network element can parse the data of the first terminal, obtain the destination address of the data, and determine the path for forwarding the data based on the destination address of the data.

[0185] When the first path includes an intermediate user plane network element, the session management network element may further send the path identifier to the intermediate user plane network element.

[0186] Optionally, the session management network element sends the path information of the first path to the user plane network element, and when there is an intermediate user plane network element, further sends the path information of the first path to the intermediate user plane network element.

[0187] Optionally, the path information further includes tunnel information of the user plane network element and / or tunnel information of the target access network element.

[0188] Specifically, when the PDU session of the first terminal corresponds to the target access network network element and the user plane network element, referring to the above step 303, if the session management network element has not previously established a communication connection between the target access network network element and the user plane network element, the session management network element can carry the tunnel information of the target access network network element in the path information and send it to the user plane network element, and carry the tunnel information of the user plane network element in the path information and send it to the target access network network element to establish a communication connection between the target access network network element and the user plane network element.

[0189] When there is an intermediate user plane network element, the session management network element can carry the tunnel information of the target access network network element and the tunnel information of the user plane network element in the path information and send them to the intermediate user plane network element, and carry the tunnel information of the intermediate user plane network element in the path information and send them to the target access network network element and the user plane network element respectively, so as to establish a communication connection between the target access network network element and the intermediate user plane network element, and a communication connection between the intermediate user plane network element and the user plane network element.

[0190] It should be noted that if the first path includes part or all of the second path, the session management network element may not send path information of the part of the first path that is the same as part or all of the second path to the user plane network element and the intermediate user plane network element.

[0191] Optionally, the session management network element determines the identification information of the first terminal based on the identification information of the PDU session; and sends the identification information of the first terminal to the user plane network element corresponding to the path identifier, so that the user plane network element determines the data corresponding to the first terminal based on the identification information of the first terminal, and then implements policy control or billing operations on the data of the first terminal.

[0192] The identification information of the first terminal includes one or more of the following: a MAC address of the first terminal, N4 interface information corresponding to the first terminal, and the like.

[0193] It should be noted that, taking the communication between the first terminal and the second terminal through the PDU session as an example, the above step 305 and / or step 305a can also be replaced by the following step 305b.

[0194] Step 305b: The session management network element sends the path identifier and identification information of the destination address corresponding to the path identifier to the user plane network element or access network element corresponding to the PDU session of the second terminal.

[0195] Specifically, the session management network element may determine a path identifier of the path between the first terminal and the second terminal based on the PDU session of the first terminal and the PDU session of the second terminal, and send the path identifier to the access network element or user plane network element corresponding to the PDU session of the second terminal. This enables the access network element or user plane network element corresponding to the PDU session of the second terminal to send the path identifier to the PDU session corresponding to the first terminal via the path corresponding to the path identifier.

[0196] For example, refer to Figure 4 Taking the example that the path between UE1 and UE2 includes RAN1, UPF1, UPF2, and RAN2 in sequence, the session management network element may determine a path identifier based on the path between UE1 and UE2, and send the path identifier to RAN2, so that RAN2 sends the path identifier to UPF2, UPF1, and RAN1 in sequence through the path; or the session management network element may send the path identifier to UPF2, so that UPF2 sends the path identifier to UPF1 and RAN1 in sequence through the path, and sends the path identifier to RAN2.

[0197] Step 306: The target access network element sends the data of the first terminal to the user plane network element according to the path identifier.

[0198] Among them, after the target access network network element receives the data from the first terminal, it can parse the data of the first terminal to obtain the destination address of the data, determine the path identifier corresponding to the first path used to forward the data based on the destination address, and send the data of the first terminal and the path identifier of the first path through the first path to the next-hop network element of the target access network network element in the first path.

[0199] Specifically, the target access network element may encapsulate the path identifier in a general packet radio service tunneling protocol for the user plane (GTP-U) packet header corresponding to the data.

[0200] In one possible design, when the session management network element uses the above-mentioned step 305 to send the path identifier and path information of the first path to the target access network network element through the mobility management network element, the target access network network element can carry the path identifier of the first path and the path information of the first path in the data of the first terminal and send it to the next-hop network element of the target access network network element in the first path. The next-hop network element determines its own next-hop network element based on the path identifier of the first path, and carries the path identifier of the first path and the path information of the first path in the data of the first terminal and sends it to its own next-hop network element through the first path until the data of the first terminal is sent to the user plane network element.

[0201] It should be noted that after the user-side network element receives the data from the first terminal, it determines that the received data is from the first terminal based on the path identifier of the first path, and can perform corresponding operations on the data of the first terminal based on the forwarding rules, billing rules, etc. set in advance for the data of the first terminal.

[0202] For example, refer to Figure 4 Taking the first path established by the session management network element for UE1 as an example, including RAN2, UPF2 and UPF1, assuming that the session management network element sends the path identifier and path information of the first path to RAN2 through the mobility management network element, RAN2 can carry the path identifier and path information of the first path in the data of UE1 and send it to UPF2. UPF2 determines that the next-hop network element of UPF2 on the first path is UPF1 based on the path information of the first path, and then carries the path identifier and path information of the first path in the data of UE1 and sends it to UPF1. UPF1 determines that the received data is from UE1 based on the path identifier of the first path, and can perform corresponding operations on the data of UE1 according to the forwarding rules, charging rules, etc. set in advance for the data of UE1.

[0203] In another possible design, when the session management network element uses the above steps 305 and 305a to send the path identifier and path information of the first path to the target access network network element, the intermediate user plane network element and the user plane network element, the target access network network element can carry the path identifier of the first path in the data of the first terminal and send it to the next hop network element of the target access network network element in the first path. The next hop network element determines its own next hop network element from the previously stored path information based on the path identifier of the first path, and carries the path identifier of the first path in the data of the first terminal and sends it to its own next hop network element via the first path until the data of the first terminal is sent to the user plane network element.

[0204] For example, refer to Figure 4Taking the example of a first path established by the session management network element for UE1 including RAN2, UPF2, and UPF1, assuming that the session management network element sends the path identifier and path information of the first path to RAN2, UPF2, and UPF1 using steps 305 and 305a above, RAN2 can carry the path identifier of the first path in UE1's data and send it to UPF2. UPF2 determines from pre-stored path information based on the path identifier of the first path that UPF2's next-hop network element on the first path is UPF1, carries the path identifier of the first path in UE1's data and sends it to UPF1. UPF1 determines that the received data is from UE1 based on the path identifier of the first path, and can perform corresponding operations on UE1's data according to forwarding rules, charging rules, etc. pre-set for UE1's data.

[0205] Step 307: The target access network element sends the data of the first terminal to the user plane element. Correspondingly, the user plane element receives the data of the first terminal.

[0206] After receiving the data from the first terminal, the target access network element may directly send the data to the user plane network element without parsing the data from the first terminal.

[0207] Step 308: The user plane network element determines a path identifier according to the destination address of the data of the first terminal.

[0208] After receiving the data of the first terminal sent by the target access network element, the user plane network element may parse the data of the first terminal to obtain the destination address of the data of the first terminal, and determine the path identifier according to the destination address.

[0209] For example, refer to Figure 4 Taking the example that the PDU session corresponding to UE1 includes RAN1 and UPF1, and the PDU session corresponding to UE2 includes RAN2 and UPF2, assuming that UPF1 receives data of UE1 from RAN1, UPF1 parses the data and finds that the destination address of the data corresponds to UE2, then UPF1 can pre-store the correspondence between the destination address and the path identifier to determine the path identifier corresponding to the destination address.

[0210] Step 309: The user plane network element carries the path identifier in the data of the first terminal and sends it to the next hop network element.

[0211] Specifically, the user plane network element may encapsulate the path identifier in a GTP-U packet header of the data.

[0212] It should be noted that after the user-side network element carries the path identifier in the data of the first terminal and sends it to the next-hop network element, the next-hop network element can determine the path identifier corresponding to the destination address of the received data according to the above step 308, and carry the determined path identifier in the data and send it to its own next-hop network element until the data is sent to the destination address.

[0213] based on Figure 3 In the method shown, a session management network element sends a path identifier to a target access network element or user plane network element, causing the target access network element or user plane network element to send the first terminal's data to the next-hop network element via the first path based on the path identifier. Compared to establishing a session tunnel by repeatedly exchanging tunnel information between the target access network element and each user plane network element corresponding to the switched path, in this embodiment of the present application, when the first path includes part or all of the second path, the session management network element can send the path identifier to the target access network element or user plane network element without re-establishing the portion of the first path that is identical to the second path, thereby reducing signaling overhead and handover latency. Furthermore, when an intermediate user plane network element exists, compared to establishing different forwarding entries based on the different destination addresses of the terminal data corresponding to different PDU sessions, in this embodiment of the present application, the intermediate user plane network element can directly establish a forwarding entry corresponding to the path identifier based on the path identifier, thereby reducing forwarding entries on the intermediate user plane network element and lowering its overhead.

[0214] It should be noted that the above Figure 3 The method shown describes that after the first terminal switches from the source access network element to the target access network element, when the session management element modifies the PDU session corresponding to the first terminal, the path identifier of the first path can be sent to the target access network element and the user plane network element corresponding to the modified PDU session of the first terminal. The session management element can also refer to the above when establishing the initial PDU session for the first terminal. Figure 3 The method shown in the figure sends the path identifier of the path corresponding to the PDU session of the first terminal to the access network element and the user plane network element corresponding to the PDU session of the first terminal, wherein the action performed by the access network element corresponding to the PDU session of the first terminal can refer to the above Figure 3 The actions performed by the target access network element in the target access network and the actions performed by the user plane network element corresponding to the PDU session of the first terminal can refer to the above Figure 3 The actions performed by the user plane network element are not described in detail here.

[0215] The above mainly introduces the solution provided by the embodiment of the present application from the perspective of interaction between devices. It is understandable that, in order to realize the above functions, each device includes a hardware structure and / or software module corresponding to the execution of each function. Those skilled in the art should easily realize that, in combination with the algorithm steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0216] In the embodiment of the present application, each network element can be divided into functional modules according to the above method example. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be noted that the division of modules in the embodiment of the present application is schematic and is only a logical functional division. In actual implementation, there may be other division methods.

[0217] In the case of dividing each functional module into corresponding functional modules, Figure 5 A communication device 50 is shown, and the communication device 50 may be a session management network element or a chip or system on chip in the session management network element. The communication device 50 may be used to perform the functions of the session management network element involved in the above embodiments. Figure 5 The communication device 50 shown includes: a sending module 501.

[0218] A sending module 501 is configured to send a path identifier to a first device; wherein the first device includes an access network element corresponding to a PDU session and a user plane network element corresponding to the PDU session; the PDU session corresponds to a first terminal; the path identifier is used to indicate a first path from the access network element to the user plane network element; the first path includes part or all of a second path, and the second path is a path corresponding to the PDU session pre-established by the session management network element for the second terminal;

[0219] The sending module 501 is also used to send the identification information of the destination address corresponding to the path identifier to the first device; so that the first device carries the path identifier corresponding to the destination address in the data according to the destination address of the received data, and forwards it through the path corresponding to the destination address.

[0220] The specific implementation of the communication device 50 can be found in Figure 3 The behavior function of the session management network element in the message forwarding method.

[0221] In one possible design, the first path is the first GTP-U path; the second path is the second GTP-U path.

[0222] In one possible design, the first path includes an intermediate user plane network element.

[0223] In one possible design, the path identifier includes a first path identifier and a second path identifier; wherein the first path identifier is used to indicate the path from the access network element to the intermediate user plane network element; and the second path identifier is used to indicate the path from the intermediate user plane network element to the user plane network element.

[0224] In one possible design, the sending module 501 is also used to send path information corresponding to the path identifier to the first device; wherein the path information includes identification information of the access network element and identification information of the user plane network element corresponding to the first path.

[0225] In one possible design, the path information includes tunnel information of the user plane network element and / or tunnel information of the access network element.

[0226] As another possible implementation method, Figure 5 The sending module 501 in the embodiment can be replaced by a transceiver, which can integrate the functions of the sending module 501. Figure 5 The communication device 50 shown may also include a memory. When the sending module 501 is replaced by a transceiver, the communication device 50 involved in the embodiment of the present application may be Figure 2 The communication device shown.

[0227] In the case of dividing each functional module into corresponding functional modules, Figure 6 A communication device is shown, and the communication device 60 may be a first device or a chip or system on chip in the first device. The communication device 60 may be used to perform the functions of the first device involved in the above embodiments. Figure 6 The communication device 60 shown includes: a receiving module 601 and a sending module 602.

[0228] A receiving module 601 is configured to receive a path identifier from a session management network element; wherein the first device includes an access network element corresponding to a protocol data unit (PDU) session and a user plane network element corresponding to the PDU session; the PDU session corresponds to a first terminal; the path identifier is used to indicate a first path from the access network element to the user plane network element; the first path includes part or all of a second path, and the second path is a path corresponding to the PDU session pre-established by the session management network element for the second terminal;

[0229] The receiving module 601 is further configured to receive identification information of a destination address corresponding to a path identifier from a session management network element;

[0230] The receiving module 601 is further configured to obtain data including a destination address from the first terminal;

[0231] The sending module 602 is further configured to forward the data through a path corresponding to the destination address of the data according to the destination address of the data.

[0232] The specific implementation of the communication device 60 can be found in Figure 3 The behavior function of the first device in the message forwarding method.

[0233] In one possible design, the first path is the first GTP-U path; the second path is the second GTP-U path.

[0234] In one possible design, the first path includes an intermediate user plane network element.

[0235] In one possible design, the path identifier includes a first path identifier and a second path identifier; wherein the first path identifier is used to indicate the path from the access network element to the intermediate user plane network element; and the second path identifier is used to indicate the path from the intermediate user plane network element to the user plane network element.

[0236] In one possible design, the receiving module 601 is also used to receive path information corresponding to the path identifier from the session management network element; wherein the path information includes the identification information of the access network element corresponding to the first path and the identification information of the user plane network element.

[0237] In one possible design, the path information includes tunnel information of the user plane network element and / or tunnel information of the access network element.

[0238] As another possible implementation method, Figure 6 The receiving module 601 in the embodiment can be replaced by a transceiver, which can integrate the functions of the receiving module 601. Figure 6 The communication device 60 shown may also include a memory. When the receiving module 601 is replaced by a transceiver, the communication device 60 involved in the embodiment of the present application may be Figure 2 The communication device shown.

[0239] The embodiment of the present application also provides a computer-readable storage medium. All or part of the processes in the above-mentioned method embodiments can be completed by a computer program to instruct the relevant hardware, and the program can be stored in the above-mentioned computer-readable storage medium. When the program is executed, it can include the processes of the above-mentioned method embodiments. The computer-readable storage medium can be an internal storage unit of the terminal (including the data sending end and / or the data receiving end) of any of the above-mentioned embodiments, such as the hard disk or memory of the terminal. The above-mentioned computer-readable storage medium can also be an external storage device of the above-mentioned terminal, such as a plug-in hard disk equipped on the above-mentioned terminal, a smart memory card (smart media card, SMC), a secure digital (secure digital, SD) card, a flash card (flash card), etc. Further, the above-mentioned computer-readable storage medium can also include both the internal storage unit of the above-mentioned terminal and an external storage device. The above-mentioned computer-readable storage medium is used to store the above-mentioned computer program and other programs and data required by the above-mentioned terminal. The above-mentioned computer-readable storage medium can also be used to temporarily store data that has been output or is to be output.

[0240] It should be noted that the terms "first" and "second" in the specification, claims, and drawings of this application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products, or devices.

[0241] It should be understood that in the present application, "at least one (item)" refers to one or more, "more than one" refers to two or more, "at least two (items)" refers to two or three and more than three, and "and / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers 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 mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0242] Through the description of the above implementation methods, technical personnel in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0243] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the modules or units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0244] The units described as separate components may or may not be physically separate, and the components shown as units may be one physical unit or multiple physical units, that is, they may be located in one place or distributed in multiple places. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0245] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0246] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling a device (which can be a single-chip microcomputer, chip, etc.) or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

[0247] The above is only a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or replacements within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A message forwarding method, characterized in that: include: The session management network element sends a path identifier to the first device; wherein the first device includes an access network network element corresponding to a protocol data unit (PDU) session and a user plane network element corresponding to the PDU session; the PDU session corresponds to a first terminal; the path identifier is used to indicate a first path from the access network element to the user plane network element; the first path includes part or all of a second path, and the second path is a path corresponding to the PDU session pre-established by the session management network element for the second terminal; the path identifier of the first path is determined based on the path identifier of the second path; The session management network element sends the identification information of the destination address corresponding to the path identifier to the first device; so that the first device carries the path identifier corresponding to the destination address in the data according to the destination address of the received data, and forwards it through the path corresponding to the destination address.

2. The method according to claim 1, characterized in that The first path is a first user-plane General Packet Radio Service Technology Tunneling Protocol GTP-U path; the second path is a second GTP-U path.

3. The method according to claim 1 or 2, characterized in that The first path includes an intermediate user plane network element.

4. The method according to claim 3, characterized in that The path identifier includes a first path identifier and a second path identifier; wherein the first path identifier is used to indicate the path from the access network element to the intermediate user plane network element; the second path identifier is used to indicate the path from the intermediate user plane network element to the user plane network element.

5. The method according to any one of claims 1, 2 and 4, characterized in that: The method further comprises: The session management network element sends path information corresponding to the path identifier to the first device; wherein the path information includes identification information of the access network element and identification information of the user plane network element corresponding to the first path.

6. The method according to claim 5, characterized in that The path information includes tunnel information of the user plane network element and / or tunnel information of the access network element.

7. A message forwarding method, characterized in that: include: A first device receives a path identifier from a session management network element; wherein the first device includes an access network element corresponding to a protocol data unit (PDU) session and a user plane network element corresponding to the PDU session; the PDU session corresponds to a first terminal; the path identifier is used to indicate a first path from the access network element to the user plane network element; the first path includes part or all of a second path, the second path being a path corresponding to the PDU session pre-established by the session management network element for the second terminal; the path identifier of the first path is determined based on the path identifier of the second path; The first device receives identification information of the destination address corresponding to the path identifier from the session management network element; The first device obtains data of the first terminal; wherein the data includes a destination address; The first device carries the path identifier corresponding to the destination address in the data according to the destination address of the data, and forwards the data through the path corresponding to the destination address.

8. The method according to claim 7, characterized in that The first path is a first user-plane General Packet Radio Service Technology Tunneling Protocol GTP-U path; the second path is a second GTP-U path.

9. The method according to claim 7 or 8, characterized in that The first path includes an intermediate user plane network element.

10. The method according to claim 9, characterized in that The path identifier includes a first path identifier and a second path identifier; wherein the first path identifier is used to indicate the path from the access network element to the intermediate user plane network element; the second path identifier is used to indicate the path from the intermediate user plane network element to the user plane network element.

11. The method according to any one of claims 7, 8 and 10, characterized in that: The method further comprises: The first device receives path information corresponding to the path identifier from the session management network element; wherein the path information includes identification information of the access network element and identification information of the user plane network element corresponding to the first path.

12. The method according to claim 11, characterized in that The path information includes tunnel information of the user plane network element and / or tunnel information of the access network element.

13. A communication device, characterized in that: The communication device includes one or more processors and transceivers; the one or more processors and the transceiver support the communication device to execute the message forwarding method as described in any one of claims 1-6, or support the communication device to execute the message forwarding method as described in any one of claims 7-12.

14. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions or programs. When the computer instructions or programs are executed on a computer, the computer executes the message forwarding method according to any one of claims 1 to 6, or the message forwarding method according to any one of claims 7 to 12.

15. A communication system, characterized in that: include: a session management network element and a first device; The session management network element is configured to send a path identifier to a first device; wherein the first device includes an access network network element corresponding to a protocol data unit (PDU) session and a user plane network element corresponding to the PDU session; the PDU session corresponds to a first terminal; the path identifier is used to indicate a first path from the access network element to the user plane network element; the first path includes part or all of a second path; the second path is a path corresponding to the PDU session established in advance by the session management network element for the second terminal; the path identifier of the first path is determined based on the path identifier of the second path; the session management network element is further configured to send identification information of a destination address corresponding to the path identifier to the first device; The first device is used to receive the path identifier from the session management network element; the first device is also used to receive identification information of the destination address corresponding to the path identifier from the session management network element; the first device is also used to obtain data from the first terminal; wherein the data includes a destination address; based on the destination address of the data, the path identifier corresponding to the destination address is carried in the data, and forwarded through the path corresponding to the destination address.

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