Method and apparatus for switching

Abstract

The present application provides a method and device for switching, the method comprising: a first control plane function network element determines at least one bearer that needs to be established when a protocol data unit PDU session of a terminal in a first network switches to a packet data network PDN connection in a second network; the first control plane function network element obtains tunnel information of the PDN connection, the tunnel information of the PDN connection includes user plane tunnel information corresponding to each bearer in the at least one bearer. The method and device for switching provided by the present application can avoid data loss during network switching, thereby ensuring normal data transmission.

Description

[0001] This application is a divisional application of the application filed on February 14, 2018, with application number 201810152399.3 and invention name “Method, device and computer-readable storage medium for switching”. Technical Field

[0002] The present application relates to the field of communications, and more particularly, to a method and device for switching in the field of communications. Background Art

[0003] With the rapid development of wireless communication technology, the fifth generation (5G) mobile communication technology has emerged. In the early stage of network deployment, due to insufficient 5G network coverage, when the location of user equipment (UE) changes, UE needs to switch sessions between 5G network and fourth generation (4G) network.

[0004] In a 4G network, a packet data network (PDN) connection corresponds to one or more bearers, where each bearer includes one or more data flows, and the system establishes a corresponding tunnel for each bearer corresponding to the PDN connection. During the handover preparation process, the source mobility management entity (MME) sends the tunnel information of each bearer corresponding to the PDN connection to the target MME, and establishes an uplink tunnel from the target access network to the packet data network (PDN) gateway user plane function (PGW-U) for each bearer.

[0005] In a 5G network, a protocol data unit (PDU) session is equivalent to a PDN connection in a 4G network. A PDU session includes one or more data flows, and all data flows in the PDU session share a tunnel.

[0006] Because in the 5G network, a PDU session shares a tunnel, while in the 4G network, each bearer of a PDN connection requires a tunnel, when the UE switches from the 5G network to the 4G network, there is a problem of how to map one tunnel into multiple tunnels. Similarly, when the UE switches from the 4G network to the 5G network, there is also a problem of how to map multiple tunnels into one tunnel.

[0007] Therefore, when the UE switches between the 4G network and the 5G network, it may not be able to receive and process data normally, resulting in data loss. Summary of the invention

[0008] The present application provides a method and device for switching, which can avoid data loss during network switching, thereby ensuring normal data transmission.

[0009] In a first aspect, the present application provides a method for switching, the method comprising: a first control plane functional network element determines at least one bearer that needs to be established when a protocol data unit (PDU) session of a terminal in a first network switches to a packet data network (PDN) connection in a second network; the first control plane functional network element obtains tunnel information of the PDN connection, and the tunnel information of the PDN connection includes user plane tunnel information corresponding to each bearer in the at least one bearer.

[0010] In the method for switching provided by an embodiment of the present application, the first control plane functional network element determines at least one bearer that needs to be established when the PDU session of the terminal in the first network is switched to the PDN connection in the second network, and obtains user plane tunnel information corresponding to each bearer in the at least one bearer, so that the first control plane functional network element establishes a user plane tunnel corresponding to the bearer in the PDN connection when the PDU session is switched to the PDN connection, which is beneficial to avoid data packet loss in the bearer included in the PDN connection during network switching, thereby ensuring normal transmission of data packets.

[0011] It should be understood that the first network may include a 5G network, and the second network may include a 4G network. It should also be understood that the PDU session in the first network is equivalent to the PDN connection in the second network.

[0012] It should be understood that the first control plane function network element may be, for example, SMF-PGW-C.

[0013] Optionally, the user plane tunnel information corresponding to each bearer may include the tunnel identifier of the user plane tunnel corresponding to each bearer and other information related to the user plane tunnel, such as the Internet Protocol (IP) address corresponding to the tunnel, which is not limited to the embodiments of the present application.

[0014] Optionally, the first control plane functional network element may determine that the PDU session in the first network needs to be established or modified under various circumstances, which is not limited in this embodiment of the present application.

[0015] In one possible implementation, the first control plane function network element may receive a first request message from the AMF, where the first request message is used to request establishment of the PDU session in the first network, where the PDU session includes at least one data stream; the first control plane function network element determines, based on the first request message, that the PDU session in the first network needs to be established.

[0016] In another possible implementation, the first control plane function network element may receive a second request message from other network elements, and the second request message triggers the first control plane function network element to modify the PDU session in the first network, for example, to add at least one data flow in the PDU session.

[0017] In another possible implementation, the first control plane function network element may trigger modification of the PDU session in the first network through its own process.

[0018] Optionally, the first control plane function network element may determine the at least one bearer according to the at least one data flow and the allocation policy.

[0019] Optionally, the at least one data flow may be, for example, a quality of service (QoS) flow, wherein the QoS flow may be divided into a guaranteed bit rate (GBR) QoS flow and a non-GBR QoS flow.

[0020] Optionally, the allocation strategy may be pre-configured, or may be indicated by other network elements through indication information, which is not limited in the embodiments of the present application.

[0021] In combination with the first aspect, in some possible implementations, the first control plane functional network element obtains tunnel information of the PDN connection, and the tunnel information of the PDN connection includes user plane tunnel information corresponding to each bearer in the at least one bearer, including: the first control plane functional network element allocates corresponding user plane tunnel information to each bearer in the at least one bearer; or, the first control plane functional network element requests the user plane functional network element corresponding to the PDU session to allocate user plane tunnel information corresponding to each bearer, and obtains user plane tunnel information corresponding to each bearer from the user plane functional network element corresponding to the PDU session.

[0022] Optionally, the first control plane function network element may obtain the user plane tunnel information corresponding to each bearer in the at least one bearer in a variety of ways, which is not limited in this embodiment of the present application.

[0023] In a possible implementation manner, the first control plane function network element may allocate user plane tunnel information to each bearer of the at least one bearer.

[0024] In another possible implementation, the first control plane functional network element may request the user plane functional network element corresponding to the PDU session to allocate user plane tunnel information for each of the at least one bearer, and obtain user plane tunnel information corresponding to each bearer from the user plane functional network element corresponding to the PDU session.

[0025] In combination with the first aspect, in some possible implementations, the tunnel information of the PDN connection also includes the control plane tunnel information corresponding to the PDN, and the first control plane function network element obtains the tunnel information of the PDN connection, which also includes: the first control plane function network element obtains the control plane tunnel information corresponding to the PDN connection.

[0026] Optionally, the control plane tunnel information corresponding to the PDN connection may include the tunnel identifier of the control plane tunnel corresponding to the PDN connection and other information related to the control plane tunnel, such as the Internet Protocol (IP) address corresponding to the control plane tunnel, which is not limited to this embodiment of the present application.

[0027] In the method for switching provided by an embodiment of the present application, the tunnel information corresponding to the PDN connection also includes the control plane tunnel information corresponding to the PDN connection, so that the first control plane functional network element establishes the control plane tunnel corresponding to the PDN connection corresponding to the PDU session, which is beneficial to avoid the loss of control signaling of the PDN connection during network switching, thereby ensuring the normal transmission of control signaling.

[0028] In combination with the first aspect, in some possible implementations, the method also includes: the first control plane function network element sends a first session management request to the user plane function network element corresponding to the PDU session, the first session management request is used to request to establish or modify the user plane tunnel corresponding to each bearer in the at least one bearer, and the first session management request carries an uplink data transmission rule, and the uplink data transmission rule is used to instruct the user plane function network element corresponding to the PDU session how to forward the uplink data received through the user plane tunnel corresponding to the PDN connection.

[0029] Optionally, when the first control plane network element itself allocates user plane tunnel information to each bearer in the at least one bearer, the first control plane function network element may carry the user plane tunnel information corresponding to each bearer in the at least one bearer in the first session management request; when the first control plane function network element requests the user plane function network element corresponding to the PDU session to allocate user plane tunnel information to each bearer in the at least one bearer, the user plane function network element corresponding to the PDU session may carry the user plane tunnel information corresponding to each bearer in the at least one bearer in the first session management response.

[0030] It should be noted that after the user plane functional network element corresponding to the PDU session obtains the user plane tunnel information corresponding to each bearer in the at least one bearer and the uplink data transmission rules corresponding to each bearer, it can complete the establishment of the uplink user plane tunnel of each bearer on the user plane functional network element corresponding to the PDU session.

[0031] In combination with the first aspect, in some possible implementations, the method further includes: the first control plane function network element obtains a bearer identifier corresponding to each bearer in the at least one bearer.

[0032] In combination with the first aspect, in some possible implementations, obtaining the bearer identifier corresponding to each bearer in the at least one bearer includes: the first control plane function network element sends a bearer identifier request to the mobility management network element through the second control plane function network element, and the bearer identifier request is used to request the allocation of a bearer identifier for each bearer in the at least one bearer; wherein the second control plane function network element is the visited control plane network element corresponding to the PDU session, and the first control plane function network element is the home control plane network element corresponding to the PDU session; the first control plane function network element receives the bearer identifier corresponding to each bearer in the at least one bearer from the mobility management network element through the second control plane function network element.

[0033] In one possible implementation, the first control plane function network element may send a bearer identification request to the mobility management network element, and the bearer identification request is used to assign a bearer identification to each bearer in the at least one bearer; accordingly, the mobility management network element receives the bearer identification request from the first control plane function network element, assigns a bearer identification to each bearer according to the bearer identification request, and sends the bearer identification corresponding to each bearer in the at least one bearer to the first control plane function network element.

[0034] It should be noted that the first control plane function network element can save the acquired user plane tunnel information corresponding to each bearer in the at least one bearer, the bearer identifier corresponding to each bearer and the control plane tunnel information corresponding to the PDN connection into the bearer context corresponding to the PDN connection, and send the bearer context to the mobility management network element when switching is prepared.

[0035] Correspondingly, the mobility management network element can complete the establishment of an uplink tunnel from the serving gateway SGW in the second network to the user plane function network element corresponding to the PDU session according to the bearer context corresponding to the PDN connection.

[0036] In one possible implementation, the first control plane function network element sends a bearer identification request to the mobility management network element through the second control plane function network element, and the bearer identification request is used to request the allocation of a bearer identification for each bearer in the at least one bearer; the first control plane function network element receives the bearer identification corresponding to each bearer in the at least one bearer from the mobility management network element through the second control plane function network element.

[0037] It should be noted that after the first control plane functional network element obtains the user plane tunnel information corresponding to each bearer in the at least one bearer, the bearer identifier corresponding to each bearer and the control plane tunnel information corresponding to the PDN connection, it can send the user plane tunnel information corresponding to each bearer in the at least one bearer, the bearer identifier corresponding to each bearer and the control plane tunnel information corresponding to the PDN connection to the second control plane functional network element when the PDU session is established / modified.

[0038] Correspondingly, the second control plane function network element can save the user plane tunnel information corresponding to each bearer in the at least one bearer obtained from the first control plane function network element, the bearer identifier corresponding to each bearer and the control plane tunnel information corresponding to the PDN connection into the bearer context of the PDN connection.

[0039] In another possible implementation, the first control plane function network element may send the tunnel information of the PDN connection to the second control plane function network element, and obtain the bearer identifier corresponding to each bearer in the at least one bearer from the second control plane function network element. Accordingly, the second control plane function network element may save the bearer identifier corresponding to each bearer in the at least one bearer.

[0040] That is to say, the first control plane function network element sends the tunnel information of the PDN connection to the second control plane function network element. The second control plane function network element determines whether it is necessary to request the mobility management network element to allocate a bearer identifier for the at least one bearer based on the tunnel information of the PDN connection, and sends a bearer identifier request to the mobility management network element when necessary.

[0041] Specifically, the first control plane function network element will first check whether there is a bearer identifier associated with the user plane tunnel information corresponding to each bearer in the tunnel information of the acquired PDN connection. If some of the at least one bearer are not assigned bearer identifiers, the mobility management network element will be requested to assign bearer identifiers to these bearers.

[0042] It should be noted that the second control plane functional network element can save the user plane tunnel information corresponding to each bearer in the at least one bearer, the bearer identifier corresponding to each bearer and the control plane tunnel information corresponding to the PDN connection into the bearer context of the PDN connection.

[0043] Since the bearer context corresponding to the PDN connection stored in the second control plane functional network element includes the user plane tunnel information corresponding to each bearer in the at least one bearer, the bearer identifier corresponding to each bearer and the control plane tunnel information corresponding to the PDN connection, the mobility management network element can obtain the bearer context corresponding to the PDN connection from the second control plane functional network element when preparing for switching, and complete the establishment of an uplink tunnel from the service gateway SGW in the second network to the user plane functional network element corresponding to the PDU based on the bearer context corresponding to the PDN connection.

[0044] In the method for switching provided in the embodiment of the present application, since the second control plane functional network element is the control plane network element to which the PDU belongs, the mobility management network element obtains the bearer context corresponding to the PDN connection from the second control plane functional network element compared to obtaining the bearer context corresponding to the PDN connection from the first control plane functional network element, thereby reducing the delay generated during the switching process.

[0045] In combination with the first aspect, in some possible implementations, the method further includes: the first control plane function network element sending tunnel information of the PDN connection and a bearer identifier corresponding to each bearer in the at least one bearer to the second control plane function network element.

[0046] In combination with the first aspect, in some possible implementations, the method also includes: the first control plane functional network element sends tunnel information of the PDN connection to the second control plane functional network element; wherein the second control plane functional network element is the visited control plane network element corresponding to the PDU session, and the first control plane functional network element is the home control plane network element corresponding to the PDU session; the first control plane functional network element receives the bearer identifier corresponding to each bearer in the at least one bearer from the second control plane functional network element.

[0047] An embodiment of the present application provides a method for switching, in which the bearer context corresponding to the PDN connection stored in the second control plane functional network element includes tunnel information of the PDN connection and a bearer identifier corresponding to each bearer in the at least one bearer, so that the mobility management network element can directly obtain the bearer context corresponding to the PDN connection from the second control plane functional network element when preparing for switching, and complete the establishment of an uplink tunnel from the service gateway SGW in the second network to the user plane functional network element corresponding to the PDU based on the bearer context corresponding to the PDN connection.

[0048] In combination with the first aspect, in some possible implementations, the first control plane functional network element obtains the tunnel information of the PDN connection, including: when the first control plane functional network element determines that it is necessary to establish the PDU session of the terminal in the first network or modify the PDU session in the first network, the first control plane functional network element obtains the tunnel information of the PDN connection.

[0049] Optionally, the first control plane function network element may obtain the tunnel information of the PDN connection when the session is established / modified, or the first control plane function network element may obtain the tunnel information of the PDN connection when the handover is prepared.

[0050] In the method for switching provided by an embodiment of the present application, the first control plane function network element obtains the tunnel information of the PDN connection when the PDU session is established or the PDU session is modified or when the switching is prepared, so that the first control plane function network element can establish the user plane tunnel corresponding to the bearer in the PDN connection and the control plane tunnel corresponding to the PDN connection before the switching is performed, which can reduce the delay during the switching process.

[0051] In combination with the first aspect, in some possible implementations, the method also includes: the first control plane functional network element sends the downlink data transmission rule corresponding to the PDN connection to the user plane functional network element corresponding to the PDU session, and the downlink data transmission rule is used to instruct the user plane functional network element corresponding to the PDU session to forward the received downlink data using the corresponding user plane tunnel.

[0052] Optionally, the first control plane functional network element may send the downlink data transmission rule corresponding to the PDN connection to the user plane functional network element corresponding to the PDU session, and the downlink data transmission rule is used to instruct the user plane functional network element corresponding to the PDU session to forward the received downlink data using the corresponding user plane tunnel.

[0053] In one possible implementation, the first control plane function network element may send a third session management request to the user plane function network element corresponding to the PDU session when switching is performed. The third session management request is used to request establishment or modification of a downlink user plane tunnel corresponding to each bearer in the at least one bearer. The third session management request carries the downlink data transmission rule.

[0054] In another possible implementation, the first control plane function network element may carry the downlink data transmission rule and the first rule indication information in the first session management request when requesting / modifying the PDU session, and the first rule indication information is used to indicate that the downlink data transmission rule is not enabled. Accordingly, when the handover is executed, the first control plane function network element sends a third session management request to the user plane function network element corresponding to the PDU session, and the third session management request carries the second rule indication information, and the second rule indication information is used to indicate that the downlink data transmission rule is enabled.

[0055] In the method for switching provided by an embodiment of the present application, the first control plane functional network element indicates the downlink data transmission rule to the user plane functional network element corresponding to the PDU session during the switching execution phase, so that the user plane functional network element corresponding to the PDU session matches the received downlink data to the corresponding downlink tunnel according to the downlink data transmission rule and sends it to the service gateway in the second network through the downlink tunnel.

[0056] In a second aspect, the present application provides a method for switching, the method comprising: a second control plane function network element receives tunnel information of a packet data network PDN connection from a first control plane function network element, the tunnel information of the PDN connection including user plane tunnel information corresponding to each bearer in at least one bearer, the second control plane function network element is a visited control plane network element corresponding to the PDN connection, and the first control plane function network element is a home control plane network element corresponding to the PDN connection; the second control plane function network element sends the tunnel information of the PDN connection to the mobility management network element.

[0057] An embodiment of the present application provides a method for switching, in which the bearer context corresponding to the PDN connection stored in the second control plane functional network element includes tunnel information of the PDN connection and a bearer identifier corresponding to each bearer in the at least one bearer, so that the mobility management network element can directly obtain the bearer context corresponding to the PDN connection from the second control plane functional network element when preparing for switching, and complete the establishment of an uplink tunnel from the service gateway SGW in the second network to the user plane functional network element corresponding to the PDU based on the bearer context corresponding to the PDN connection.

[0058] In addition, since the second control plane functional network element is the control plane network element to which the PDU belongs, the mobility management network element obtains the bearer context corresponding to the PDN connection from the second control plane functional network element compared to obtaining the bearer context corresponding to the PDN connection from the first control plane functional network element, which can reduce the delay generated during the switching process.

[0059] It should be understood that the first control plane function network element may be, for example, SMF-PGW-C, and the second control plane function network element may be, for example, v-SMF.

[0060] In combination with the second aspect, in some possible implementations, the tunnel information of the PDN connection also includes control plane tunnel information corresponding to the PDN connection.

[0061] In the method for switching provided by an embodiment of the present application, the tunnel information corresponding to the PDN connection also includes the control plane tunnel information corresponding to the PDN connection, so that the first control plane functional network element establishes the control plane tunnel corresponding to the PDN connection corresponding to the PDU session, which is beneficial to avoid the loss of control signaling of the PDN connection during network switching, thereby ensuring the normal transmission of control signaling.

[0062] In combination with the second aspect, in some possible implementations, the method also includes: the second control plane function network element forwards to the mobility management network element a bearer identification request sent by the first control plane function to the mobility management network element, the bearer identification request being used to request allocation of a bearer identification for each bearer in the at least one bearer; the second control plane function network element forwards to the first control plane function network element the bearer identification corresponding to each bearer in the at least one bearer sent by the mobility management network element to the first control plane function.

[0063] That is to say, the second control plane function network element has the function of transparently transmitting messages transmitted between the first control plane function network element and the user plane function network element corresponding to the PDU session.

[0064] In combination with the second aspect, in some possible implementations, the method further includes: the second control plane function network element receiving a bearer identifier corresponding to each bearer in the at least one bearer from the first control plane function network element.

[0065] In combination with the second aspect, in some possible implementations, the method also includes: the second control plane function network element sends a bearer identification request to the mobility management network element based on the tunnel information of the PDN connection, and the bearer identification request is used to request the allocation of a bearer identification for each bearer in the at least one bearer; the second control plane function network element receives the bearer identification corresponding to each bearer in the at least one bearer from the mobility management network element.

[0066] Specifically, the second control plane network element can check whether there is a bearer identifier associated with the user plane tunnel information corresponding to each bearer in the tunnel information of the PDN connection. If it is determined that at least one bearer is not assigned a bearer identifier, the mobility management network element is requested to assign a bearer identifier to each bearer in at least one bearer that is not assigned a bearer identifier.

[0067] That is to say, the second control plane function network element may have a processing function.

[0068] In combination with the second aspect, in some possible implementations, the method also includes: the second control plane function network element saves the bearer identifier corresponding to each bearer in the at least one bearer, and sends the bearer identifier corresponding to each bearer in the at least one bearer to the first control plane function network element.

[0069] In a third aspect, the present application provides a method for switching, the method comprising: a first control plane functional network element determines that a packet data network PDN connection of a terminal in a second network needs to be switched to a protocol data unit PDU session in the first network; the first control plane functional network element obtains user plane tunnel information corresponding to the PDU session.

[0070] In the method for switching provided by an embodiment of the present application, the first control plane functional network element determines that the PDN connection of the terminal in the second network needs to be switched to the PDU session in the first network, and obtains the user plane tunnel information corresponding to the PDU session, so that the first control plane functional network element establishes the user plane tunnel corresponding to the PDU session when the PDN connection is switched to the PDU session, which is beneficial to avoid the loss of data packets in the PDU session during the network switching process, thereby ensuring the normal transmission of data packets.

[0071] It should be understood that the first control plane function network element may be, for example, SMF-PGW-C.

[0072] It should also be understood that the PDU session in the first network is equivalent to the PDN connection in the second network.

[0073] In one possible implementation, the first control plane functional network element may receive a third request message, where the third request message is used to request establishment of the PDN connection in the second network; the first control plane functional network element determines, based on the third request message, that the PDN connection of the terminal in the second network needs to be switched to the PDU session in the first network.

[0074] In one possible implementation, the first control plane function network element may receive a second session management request, the second session management request carrying first indication information, the first indication information being used to indicate preparation for switching the terminal from the second network to the first network; the first control plane function network element may determine, based on the first indication information, that the PDN connection in the second network needs to be switched to the PDU session in the first network.

[0075] In combination with the third aspect, in some possible implementations, the first control plane functional network element obtains the user plane tunnel information corresponding to the PDU session, including: the first control plane functional network element allocates the user plane tunnel information corresponding to the PDU session to the PDU session; or the first control plane functional network element requests the user plane functional network element corresponding to the PDN connection to allocate the user plane tunnel information corresponding to the PDU session, and obtains the user plane tunnel information corresponding to the PDU session sent by the user plane functional network element corresponding to the PDN connection.

[0076] Optionally, the first control plane functional network element may obtain the user plane tunnel information corresponding to the PDU session in a variety of ways, which is not limited in this embodiment of the present application.

[0077] In a possible implementation manner, the first control plane function network element may allocate user plane tunnel information corresponding to the PDU session to the PDU session itself.

[0078] In another possible implementation, the first control plane functional network element requests the user plane functional network element corresponding to the PDN connection to allocate user plane tunnel information corresponding to the PDU session, and obtains user plane tunnel information corresponding to the PDU session sent from the user plane functional network element corresponding to the PDN connection.

[0079] In combination with the third aspect, in some possible implementations, the method also includes: the first control plane function network element sends a first session management request to the user plane function network element corresponding to the PDN connection, the first session management request is used to request to establish or modify the user plane tunnel corresponding to the PDU session, the first session management request carries an uplink data transmission rule, and the uplink data transmission rule is used to instruct the user plane function network element corresponding to the PDN connection how to forward the uplink data received through the user plane tunnel corresponding to the PDU session.

[0080] Optionally, when the first control plane network element itself allocates user plane tunnel information for the PDU session, the first control plane functional network element may carry the user plane tunnel information corresponding to the PDU session in the first session management request; when the first control plane functional network element requests the user plane functional network element corresponding to the PDN connection to allocate user plane tunnel information for the PDU session, the user plane functional network element corresponding to the PDN connection may carry the user plane tunnel information corresponding to the PDU session in the first session management response.

[0081] Optionally, since the PDN connection in the second network may be updated when the session is modified, such as some new bearers are created, the user plane functional network element corresponding to the PDN connection needs to know the updated uplink data transmission rules in order to associate the data flows corresponding to these bearers with the user plane tunnel corresponding to the PDU session.

[0082] In combination with the third aspect, in some possible implementations, the method also includes: when the first control plane functional network element determines that the uplink data transmission rule has changed, sending the updated uplink data transmission rule to the user plane functional network element corresponding to the PDN connection.

[0083] Optionally, when the first control plane functional network element allocates user plane tunnel information for the PDU session by itself, the first control plane functional network element can obtain the user plane tunnel information corresponding to the PDU session in the same stage, and send the user plane tunnel information corresponding to the PDU session to the user plane functional network element corresponding to the PDN connection, or obtain the user plane tunnel information corresponding to the PDU session at different stages, and send the user plane tunnel information corresponding to the PDU session to the user plane functional network element corresponding to the PDN connection. The embodiments of the present application are not limited to this.

[0084] In one possible implementation, the first control plane functional network element can obtain the user plane tunnel information and the uplink data transmission rules corresponding to the PDU session when the session is established / modified, and send the user plane tunnel information and the uplink data transmission rules corresponding to the PDU session to the user plane functional network element corresponding to the PDN connection.

[0085] In another possible implementation, the first control plane functional network element can obtain the user plane tunnel information and the uplink data transmission rules corresponding to the PDU session when preparing for network switching, and send the user plane tunnel information and the uplink data transmission rules corresponding to the PDU session to the user plane functional network element corresponding to the PDN connection.

[0086] In another possible implementation, the first control plane functional network element can obtain the user plane tunnel information and the uplink data transmission rules corresponding to the PDU session when the session is established / modified, and send the user plane tunnel information and the uplink data transmission rules corresponding to the PDU session to the user plane functional network element corresponding to the PDN connection when the network switching is prepared.

[0087] In the method for switching provided by the embodiment of the present application, the first control plane functional network element determines and sends the user plane tunnel information corresponding to the PDU session to the user plane functional network element corresponding to the PDN connection during the switching preparation stage, thereby avoiding the update of the uplink data transmission rules due to the newly added bearer when the session is established / modified.

[0088] In combination with the third aspect, in some possible implementations, before the first control plane function network element sends a first session management request to the user plane function network element corresponding to the PDN connection, the method also includes: the first control plane function network element receives a second session management request, the second session management request carries first indication information, and the first indication information is used to indicate preparation for the terminal to switch from the second network to the first network.

[0089] In combination with the third aspect, in some possible implementations, the method also includes: the first control plane functional network element sends the downlink data transmission rule corresponding to the PDU session to the user plane functional network element corresponding to the PDN connection, and the downlink data transmission rule is used to indicate that the downlink data packet received by the user plane functional network element corresponding to the PDN connection is sent through the user plane tunnel corresponding to the PDU session.

[0090] In one possible implementation, the first control plane function network element may send a third session management request to the user plane function network element corresponding to the PDN connection when switching is performed, and the third session management request is used to request modification of the downlink user plane tunnel corresponding to the PDU session, and the third session management request carries the downlink data transmission rule.

[0091] In another possible implementation, the first control plane function network element may carry the downlink data transmission rule and the first rule indication information in the first session management request when the session is established / modified, and the first rule indication information is used to indicate that the downlink data transmission rule is not enabled. Accordingly, when the handover is executed, the first control plane function network element sends a third session management request to the user plane function network element corresponding to the PDN connection, and the third session management request carries the second rule indication information, and the second rule indication information is used to indicate that the downlink data transmission rule is enabled.

[0092] In the method for switching provided in the embodiment of the present application, the first control plane function network element indicates a downlink data transmission rule to the user plane function network element corresponding to the PDN connection during the switching execution phase, so that the user plane function network element corresponding to the PDN connection matches the received downlink data to the corresponding downlink tunnel according to the downlink data transmission rule and sends it to the V-UPF or access network (for example) in the first network through the downlink tunnel. Figure 1 or Figure 2 V-UPF or access network in the network).

[0093] In a fourth aspect, the present application provides a communication system, which includes a first control plane function network element and a user plane function network element. The first control plane function network element is used to: determine at least one bearer that needs to be established when the protocol data unit PDU session of the terminal in the first network is switched to the packet data network PDN connection in the second network; obtain tunnel information of the PDN connection, the tunnel information of the PDN connection includes user plane tunnel information corresponding to each bearer in the at least one bearer; send a first session management request to the user plane function network element, the first session management request is used to request to establish or modify the user plane tunnel corresponding to each bearer in the at least one bearer, the first session management request carries an uplink data transmission rule and the tunnel information of the PDN connection, the uplink data transmission rule is used to indicate how the user plane function network element corresponding to the PDU session forwards the uplink data received through the user plane tunnel corresponding to the PDN connection. The user plane function network element is used to receive the first session management request from the first control plane function network element; according to the first session management request, send a first session management response to the first control plane management network element. The first control plane function network element is also used to receive the first session management response from the user plane function network element.

[0094] In combination with the fourth aspect, in some possible implementations, the first session management request further carries a downlink transmission rule and first rule indication information, the downlink data transmission rule is used to instruct the user plane function network element corresponding to the PDU session to forward the received downlink data using the corresponding user plane tunnel, and the first rule indication information is used to indicate that the downlink data transmission rule is not enabled;

[0095] Optionally, the first control plane function network element is further used to send second rule indication information to the user plane function network element, where the second rule indication information is used to indicate enabling of the downlink data transmission rule.

[0096] In combination with the fourth aspect, in some possible implementations, the first control plane function network element is further used to send the downlink data transmission rule to the user plane function network element.

[0097] In a fifth aspect, an embodiment of the present application provides a communication system, which includes: a first control plane function network element and a user plane function network element. The first control plane function network element is used to determine at least one bearer that needs to be established when the protocol data unit PDU session of the terminal in the first network switches to the packet data network PDN connection in the second network; send a first session management request to the user plane function network element, the first session management request is used to request to establish or modify the user plane tunnel corresponding to each bearer in the at least one bearer, and the first session management request carries an uplink data transmission rule, and the uplink data transmission rule is used to instruct the user plane function network element corresponding to the PDU session how to forward the uplink data received through the user plane tunnel corresponding to the PDN connection. The user plane function network element is used to receive the first session management request from the first control plane function network element, and determine the tunnel information of the PDN connection according to the first session management request, and the tunnel information of the PDN connection includes the user plane tunnel information corresponding to each bearer in the at least one bearer; send a first session management response to the first control plane function network element, and the first session management response carries the tunnel information of the PDN connection. The first control plane function network element is further used to receive the first session management response from the user plane function network element.

[0098] In combination with the fifth aspect, in some possible implementations, the first session management request also carries a downlink transmission rule and a first rule indication information. The downlink data transmission rule is used to instruct the user plane functional network element corresponding to the PDU session to forward the received downlink data using the corresponding user plane tunnel, and the first rule indication information is used to indicate that the downlink data transmission rule is not enabled.

[0099] Optionally, the first control plane function network element is further used to send second rule indication information to the user plane function network element, where the second rule indication information is used to indicate enabling of the downlink data transmission rule.

[0100] In combination with the fifth aspect, in some possible implementations, the first control plane function network element also sends the downlink data transmission rule to the user plane function network element.

[0101] In a sixth aspect, an embodiment of the present application provides a device for switching, comprising a unit for executing each step of the method for switching in the above-mentioned first aspect or any one of the implementations of the first aspect.

[0102] In a seventh aspect, an embodiment of the present application provides a device for switching, comprising a unit for executing each step of the method for switching in the above-mentioned second aspect or any one of the implementations of the second aspect.

[0103] In an eighth aspect, an embodiment of the present application provides a device for switching, comprising a unit for executing each step of the method for switching in the above-mentioned third aspect or any one of the implementations of the third aspect.

[0104] In the ninth aspect, an embodiment of the present application provides a device for switching, which may be a device for switching in the above-mentioned method design, or a chip configured in a device for switching. The device: includes a processor, a memory, and a communication interface. Among them, the processor, the memory, and the communication interface can communicate through a bus, or can communicate through other means such as wireless transmission. The memory is used to store instructions, and the processor is used to execute instructions stored in the memory. The memory stores program code, and the processor can call the program code stored in the memory to execute the method for switching in the first aspect or any possible implementation of the first aspect.

[0105] In the tenth aspect, an embodiment of the present application provides a device for switching, which may be a device for switching in the above-mentioned method design, or a chip configured in a device for switching. The device: includes a processor, a memory, a communication interface and a bus. Among them, the processor, the memory, and the communication interface can communicate through the bus, or can communicate through other means such as wireless transmission. The memory is used to store instructions, and the processor is used to execute instructions stored in the memory. The memory stores program code, and the processor can call the program code stored in the memory to execute the method for switching in the second aspect or any possible implementation of the second aspect.

[0106] In the eleventh aspect, an embodiment of the present application provides a device for switching, which may be a device for switching in the above-mentioned method design, or a chip configured in a device for switching. The device: includes a processor, a memory, and a communication interface. Among them, the processor, the memory, and the communication interface can communicate through a bus, or can communicate through other means such as wireless transmission. The memory is used to store instructions, and the processor is used to execute instructions stored in the memory. The memory stores program code, and the processor can call the program code stored in the memory to execute the method for switching in the third aspect or any possible implementation of the third aspect.

[0107] In the twelfth aspect, a chip system is provided, which includes a processor for implementing the functions involved in the above aspects, for example, generating, receiving, sending, or processing the data and / or information involved in the above methods. In one possible design, the chip system also includes a memory, which is used to store program instructions and data necessary for the switching device. Specifically, the program instructions stored in the memory include instructions for executing the method for switching in any possible implementation of the first to third aspects and the first to third aspects.

[0108] Optionally, the chip system may be composed of a chip, or may include a chip and other discrete devices.

[0109] In a thirteenth aspect, a computer program product is provided, the computer program product comprising: a computer program code, when the computer program code is run on a computer, causing the computer to execute the method for switching according to the above-mentioned first to third aspects and any possible implementation of the first to third aspects.

[0110] In a fourteenth aspect, a computer-readable medium is provided, wherein the computer-readable medium stores a program code executed by a switching device, wherein the program code includes instructions for executing a method for switching in accordance with the first to third aspects and any possible implementation of any one of the first to third aspects.

[0111] Based on the implementations provided in the above aspects, the present application can also be further combined to provide more implementations. BRIEF DESCRIPTION OF THE DRAWINGS

[0112] Figure 1 It is a schematic diagram of the system architecture provided by the embodiment of the present application;

[0113] Figure 2 is a schematic diagram of another system architecture provided by an embodiment of the present application;

[0114] Figure 3 is a schematic flow chart of a method for switching provided in an embodiment of the present application;

[0115] Figure 4 is a schematic flow chart of another method for switching provided in an embodiment of the present application

[0116] Figure 5 It is a schematic flowchart of another method for switching provided in an embodiment of the present application.

[0117] Figure 6 is a schematic flow chart of another method for switching provided in an embodiment of the present application;

[0118] Figure 7 is a schematic flow chart of another method for switching provided in an embodiment of the present application;

[0119] Figure 8 is a schematic flow chart of another method for switching provided in an embodiment of the present application;

[0120] Fig. 9 is a schematic flow chart of another method for switching provided in an embodiment of the present application;

[0121] Fig.10 is a schematic flow chart of another method for switching provided in an embodiment of the present application;

[0122] Fig.11 is a schematic flow chart of another method for switching provided in an embodiment of the present application;

[0123] Fig.12 is a schematic flow chart of another method for switching provided in an embodiment of the present application;

[0124] Fig.13 is a schematic block diagram of a device for switching provided in an embodiment of the present application;

[0125] Fig.14 is a schematic block diagram of another device for switching provided in an embodiment of the present application;

[0126] Fig.15 is a schematic block diagram of another device for switching provided in an embodiment of the present application;

[0127] Fig.16 is a schematic block diagram of another device for switching provided in an embodiment of the present application;

[0128] Fig.17 is a schematic block diagram of another device for switching provided in an embodiment of the present application;

[0129] Fig.18 It is a schematic block diagram of another device for switching provided in an embodiment of the present application. DETAILED DESCRIPTION

[0130] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0131] First, combine Figure 1 and Figure 2 Introduce the application scenarios of the embodiments of the present application. Figure 1 and Figure 2 They are schematic diagrams of system architecture 100 and system architecture 200 provided in embodiments of the present application. Figure 1 The interworking system architecture 100 of the 4G network and the 5G network in a non-roaming scenario is shown. Figure 2 The system architecture 200 of intercommunication between 4G network and 5G network in the scenario of home routing or home routing roaming is shown.

[0132] Specifically, the system architecture 100 and the system architecture 200 may include network elements in a 4G network and network elements in a 5G network. Some modules in the system architecture 100 and the system architecture 200 include functions of network elements in a 4G network and network elements in a 5G network, such as a user plane function (UPF) + PGW-U module, a session management function (SMF) + PDN gateway control plane function (PGW-C) module, a policy control function (PCF) + policy and charging rules function (PCRF) module, and a home subscriber server (HSS) + unified data management (UDM) module.

[0133] UPF+PGW-U module: used for transmission management of user data. In the intercommunication system architecture, this module can be used for both 4G data transmission and 5G data transmission functions.

[0134] SMF+PGW-C module: used for session establishment, deletion, and modification management. In the intercommunication system architecture, this module can provide both 4G and 5G session management functions.

[0135] PCF+PCRF module: used for policy and charging control. In the intercommunication system architecture, this module can provide both 4G policy and charging control and 5G policy and charging control for terminals.

[0136] HSS+UDM module: used to store user subscription data. In the intercommunication system architecture, this module stores both the 4G subscription information and the 5G subscription information of the terminal.

[0137] It should be understood that the above "+" means joint establishment, UPF is the user plane function of the 5G network, PGW-U is the gateway user plane function of the 4G network corresponding to UPF; SMF is the session management function of the 5G network, PGW-C is the gateway control plane function in the 4G network corresponding to SMF; PCF is the policy control function of the 5G network, and PCRF is the policy charging rule function of the 4G network corresponding to PCF. The "joint establishment" here means that the same module can have the functions of two network function entities at the same time.

[0138] In the embodiment of the present application, for the convenience of description, the HSS+UDM entity is referred to as the user data management network element, the SMFHPGW-C is referred to as the control plane function network element, and the UPF+PGW-U is referred to as the user plane function network element, which is uniformly described here and will not be repeated below. Of course, the above-mentioned network devices after being combined can also be called by other names, which are not specifically limited in the embodiment of the present application.

[0139] In addition, the system architecture 100 and the system architecture 200 may also include: an MME module, a serving gateway (SGW) module, and an access and mobility management function (AMF) module in the 5G network.

[0140] MME module: used for user mobility management. For example, it mainly includes user attachment management, reachability management, mobility management, paging management, access authentication and authorization, encryption and integrity protection of non-access layer signaling, etc.

[0141] SGW module: User plane gateway, user plane termination point with the evolved universal terrestrial radio access network (E-UTRAN). Manages the routing and transmission of data packets, adds transport layer packet labels, etc.

[0142] AMF module: used for user access and mobility management, mainly including user registration management, reachability management, mobility management, paging management, access authentication and authorization, encryption and integrity protection of non-access layer signaling, etc.

[0143] Among them, the terminal accesses the 4G network through E-UTRAN, and the terminal accesses the 5G network through the next generation radio access network (NG-RAN).

[0144] NG-RAN: Used to provide wireless air interface access to the core network for terminals to obtain corresponding services.

[0145] E-UTRAN: used for wireless resource management, establishing, modifying or deleting air interface resources for terminals, providing data and signaling transmission for terminals, etc.

[0146] The communication interface between the above modules in the system architecture 100 and the system architecture 200 will be introduced below.

[0147] S1-MME interface: control plane interface between MME and E-UTRAN.

[0148] S1-U interface: user plane interface between S-GW and E-UTRAN.

[0149] S5-U interface: user plane interface between SGW and PGW-U, used to transmit user plane data of UE.

[0150] S5-C interface: control plane management interface between SGW and PGW-U, used to establish SGW and PGW-U user plane connection for UE.

[0151] S6a interface: The interface between MME and HSS, used to obtain user subscription data and perform authentication and authorization functions for UE.

[0152] S11 interface: The interface between SGW and MME, used to establish the bearer of the user plane.

[0153] N1 interface: the interface between UE and AMF, for signaling management and transmission of user non-access layer.

[0154] N2 interface: The interface between NG-RAN and AMF, used for signaling transmission.

[0155] N3 interface: The interface between UPF and NG-RAN, used to transmit user data.

[0156] N4 interface: The interface between SMF and UPF, used to establish the transmission channel of the user plane.

[0157] N7 interface: The interface between SMF and PCF, used for formulation and distribution of policy control and charging information.

[0158] N8 interface: The interface between AMF and UDM, used to obtain user mobility-related subscription information, etc.

[0159] N10 interface: The interface between SMF and UDM, used to obtain user session management-related contract information, etc.

[0160] N11 interface: The interface between SMF and AMF, used for transmission of session management information, etc.

[0161] N15 interface: The interface between AMF and PCF, used to obtain access and mobility related policy information.

[0162] In addition, in the system architecture 200, HPLMN represents a home network, and VPLMN represents a visited network or a roaming network. For example, HPLMN represents a home public land mobile network (HPLMN), and VPLMN represents a visited or roaming PLMN. Specifically, v-SMF represents an SMF in a roaming network; and v-UPF represents an UPF in a roaming network.

[0163] It should be understood that in system architecture 100 and system architecture 200, in order to support the intercommunication between 4G network and 5G network, a first interface is introduced. The first interface refers to the communication interface between AMF in 5G network and MME in 4G network, and the first interface can be represented by N26 interface. The support of N26 interface in system architecture is optional, and the switching process can only be used in the intercommunication system architecture supporting N26 interface to ensure the continuity of business.

[0164] It should also be understood that since the embodiments of the present application involve a terminal switching process between a 4G network and a 5G network, the system architecture 100 and the system architecture 200 support the N26 interface.

[0165] It should be noted that in system architecture 100 and system architecture 200, the interface name between each module is only an example. In a specific implementation, the interface name may be other names, and the embodiments of the present application do not specifically limit this.

[0166] It should also be noted that in the system architecture 100 and the system architecture 200, the NG-RAN in the 5G network can also be referred to as an access device, which refers to a device that accesses the core network, such as a base station, a broadband network gateway (BNG), an aggregation switch, a non-3GPP access device, etc. Among them, the base station can be a base station in various forms including a macro base station, a micro base station (also called a small station), a relay station, an access point, etc., and the embodiments of the present application are not limited to this.

[0167] Of course, in system architecture 100 and system architecture 200, there may be other modules in the 4G network and the 5G network. For example, the 4G network may also include a general packet radio system (GPRS) service support node (SGSN) module, etc., and the 5G network may also include an authentication server function (AUSF) module and a network slice selection function (NSSF) module, etc., which are not limited to the embodiments of the present application.

[0168] The terminal involved in the embodiments of the present application may include various handheld devices, vehicle-mounted devices, wearable devices, computing devices or other processing devices connected to a wireless modem with wireless communication functions; it may also include a subscriber unit, a cellular phone, a smartphone, a wireless data card, a personal digital assistant (PDA) computer, a tablet computer, a wireless modem, a handheld device (handheld), a laptop computer, a cordless phone or a wireless local loop (WLL) station, a machine type communication (MTC) terminal, a user equipment (UE), a mobile station (MS), a terminal device, etc. For the convenience of description, they are collectively referred to as terminals in the embodiments of the present application.

[0169] It should be understood that as the terminal continues to move, the change in the terminal's location may cause the terminal to switch between different networks. For example, when the terminal moves from a 4G network to a 5G network, it is necessary to switch from the PDN connection in the 4G network to the PDU session in the 5G network, or when the terminal switches from a 5G network to a 4G network, it is necessary to switch from the PDU session in the 5G network to the PDN connection in the 4G network.

[0170] In a 4G network, a PDN connection is allocated with a control plane tunnel corresponding to the PDN connection, and the control plane tunnel is used to transmit control signaling corresponding to the PDN connection. The PDN connection includes at least one bearer, and each of the at least one bearer is allocated with a user plane tunnel corresponding to each bearer, and the user plane tunnel corresponding to each bearer is used to transmit at least one data stream included in each bearer.

[0171] That is to say, one PDN connection corresponds to one control plane tunnel, and one bearer in one PDN connection corresponds to one user plane tunnel.

[0172] In a 5G network, a PDU session includes at least one data flow, and a user plane tunnel corresponding to the PDU session is allocated to the PDU session. There is no control plane tunnel corresponding to the PDU session in 5G.

[0173] That is to say, a PDU session does not allocate a control plane tunnel, and one PDU session corresponds to one user plane tunnel.

[0174] Therefore, when the terminal switches between two networks, the following problems occur:

[0175] (1) When a terminal switches from a 4G network to a 5G network, how is at least one user plane tunnel (e.g., multiple user plane tunnels) corresponding to a PDN connection mapped to a user plane tunnel corresponding to a PDU session?

[0176] (2) When a terminal switches from a 5G network to a 4G network, how is a user plane tunnel corresponding to a PDU session mapped to at least one user plane tunnel (e.g., multiple user plane tunnels) corresponding to a PDN connection?

[0177] (3) When the terminal switches from the 5G network to the 4G network, how to establish the control plane tunnel corresponding to the PDN connection in the 4G network.

[0178] The above problems may cause data packet loss during the network switching process, thereby affecting the normal transmission of data packets.

[0179] The method and device for switching provided by the embodiments of the present application are helpful in avoiding the loss of data packets during network switching, thereby ensuring the normal transmission of data packets.

[0180] Figure 3 A schematic flow chart of a method 300 for switching provided in an embodiment of the present application is shown. The method 300 can be applied to Figure 1 or Figure 2 The method 300 may also be applied to other similar architectures, which is not limited in the embodiments of the present application.

[0181] It should be understood that the method 300 may be executed by a first control plane function network element, and the first control plane function network element may be, for example, Figure 1 or Figure 2 The SMF-PGW-C shown in .

[0182] S310: The first control plane function network element determines at least one bearer that needs to be established when a PDU session of a terminal in a first network is switched to a PDN connection in a second network.

[0183] S320, the first control plane function network element obtains tunnel information of the PDN connection, where the tunnel information of the PDN connection includes user plane tunnel information corresponding to each bearer in the at least one bearer.

[0184] It should be understood that the first network may include a 5G network, and the second network may include a 4G network. It should also be understood that the PDU session in the first network is equivalent to the PDN connection in the second network.

[0185] Optionally, in S310, the first control plane functional network element may, when determining that the PDU session in the first network needs to be established or modified, determine at least one bearer that needs to be established when the PDU session of the terminal in the first network switches to the PDN connection in the second network.

[0186] Optionally, in S310, the first control plane functional network element may determine that the PDU session in the first network needs to be established or modified under various circumstances, which is not limited in this embodiment of the present application.

[0187] In one possible implementation, the first control plane function network element may receive a first request message from the AMF, where the first request message is used to request establishment of the PDU session in the first network, where the PDU session includes at least one data stream; the first control plane function network element determines, based on the first request message, that the PDU session in the first network needs to be established.

[0188] In another possible implementation, the first control plane function network element may receive a second request message from other network elements, and the second request message triggers the first control plane function network element to modify the PDU session in the first network, for example, to add at least one data flow in the PDU session.

[0189] In another possible implementation, the first control plane function network element may trigger modification of the PDU session in the first network through its own process.

[0190] Optionally, the first control plane function network element may determine the at least one bearer according to the at least one data flow and the allocation policy.

[0191] Optionally, the at least one data flow may be, for example, a quality of service (QoS) flow, wherein the QoS flow may be divided into a guaranteed bit rate (GBR) QoS flow and a non-GBR QoS flow.

[0192] Optionally, the allocation strategy may be pre-configured, or may be indicated by other network elements through indication information, which is not limited in the embodiments of the present application.

[0193] Optionally, the embodiment of the present application does not limit the specific content of the allocation strategy. For example, the allocation strategy may be:

[0194] (1) The default bearer shared by all non-GBR QoS flows in a PDU session;

[0195] (2) Different GBR QoS flows in a PDU session use different dedicated bearers;

[0196] (3) A dedicated bearer shared by several different GBR QoS flows in a PDU session.

[0197] For example, when the session is established, if the at least one data flow includes 5 GBR QoS flows and 6 non-GBR QoS flows, the first control plane functional network element establishes a dedicated bearer for each of the above 5 GBR QoS flows, and establishes a common default bearer for the above 6 non-GBR QoS flows.

[0198] For another example, when a session is modified, if a dedicated bearer 1 and a dedicated bearer 2 have been established for the PDU session when the PDU session is established, and the at least one data flow includes 1 GBR QoS flow and 1 non-GBR QoS flow, the first control plane functional network element establishes a dedicated bearer 3 for the above-mentioned 1 GBR QoS flow, and establishes a public default bearer for the above-mentioned non-1 GBR QoS flow.

[0199] For another example, when a session is modified, if a dedicated bearer 1, a dedicated bearer 2 and a default bearer have been established for the PDU session when the PDU session is established, and the at least one data flow includes 1 GBR QoS flow and 1 non-GBR QoS flow, the first control plane functional network element establishes a dedicated bearer 3 for the above-mentioned 1 GBR QoS flow, and the above-mentioned 1 non-GBR QoS flow shares the default bearer with other non-GBR QoS flows in the default bearer.

[0200] Optionally, the user plane tunnel information corresponding to each bearer in S320 may include the tunnel identifier of the user plane tunnel corresponding to each bearer and other information related to the user plane tunnel, such as the Internet Protocol (IP) address corresponding to the tunnel, which is not limited to this embodiment of the present application.

[0201] Optionally, in S320, the first control plane function network element may obtain the user plane tunnel information corresponding to each bearer in the at least one bearer in a variety of ways, which is not limited in this embodiment of the present application.

[0202] In a possible implementation manner, the first control plane function network element may allocate user plane tunnel information to each bearer of the at least one bearer.

[0203] In another possible implementation, the first control plane functional network element may request the user plane functional network element corresponding to the PDU session to allocate user plane tunnel information for each of the at least one bearer, and obtain user plane tunnel information corresponding to each bearer from the user plane functional network element corresponding to the PDU session.

[0204] In the method for switching provided by an embodiment of the present application, the first control plane functional network element determines at least one bearer that needs to be established when the PDU session of the terminal in the first network is switched to the PDN connection in the second network, and obtains user plane tunnel information corresponding to each bearer in the at least one bearer, so that the first control plane functional network element establishes a user plane tunnel corresponding to the bearer in the PDN connection when the PDU session is switched to the PDN connection, which is beneficial to avoid data packet loss in the bearer included in the PDN connection during network switching, thereby ensuring normal transmission of data packets.

[0205] It should be understood that the first control plane function network element in this embodiment and the user plane function network element corresponding to the PDU session may be respectively Figure 1 or Figure 2 SMF+PGW-C and UPF+PGW-U in the system architecture shown in.

[0206] Optionally, the method 300 also includes: the first control plane functional network element sends an uplink data transmission rule to the user plane functional network element corresponding to the PDU session, and the uplink data transmission rule is used to instruct the user plane functional network element corresponding to the PDU session how to forward the uplink data received through the user plane tunnel corresponding to the PDN connection, for example, sending the uplink data packet to an external data network through a specified forwarding path.

[0207] In one possible implementation, the first control plane function network element may send a first session management request to the user plane function network element corresponding to the PDU session, where the first session management request is used to request establishment or modification of a user plane tunnel corresponding to each bearer in the at least one bearer, and the first session management request carries the uplink data transmission rule.

[0208] Correspondingly, the user plane function network element corresponding to the PDU session can receive the first session management request from the first control plane function network element, and send a first session management response to the first control plane function network element according to the first session management request.

[0209] Optionally, the first session management request may be an N4 session management request, and the second session management response may be an N4 session management response.

[0210] It should be understood that in an embodiment of the present application, the N4 session management request may be an N4 session establishment request or an N4 session modification request transmitted through the N4 interface between the first control plane function network element and the user plane function network element corresponding to the PDU session; accordingly, the N4 session management response may be an N4 session establishment response or an N4 session modification response transmitted through the N4 interface between the first control plane function network element and the user plane function network element corresponding to the PDU session.

[0211] Optionally, when the first control plane network element itself allocates user plane tunnel information to each bearer in the at least one bearer, the first control plane function network element may carry the user plane tunnel information corresponding to each bearer in the at least one bearer in the first session management request; when the first control plane function network element requests the user plane function network element corresponding to the PDU session to allocate user plane tunnel information to each bearer in the at least one bearer, the user plane function network element corresponding to the PDU session may carry the user plane tunnel information corresponding to each bearer in the at least one bearer in the first session management response.

[0212] It should be noted that after the user plane functional network element corresponding to the PDU session obtains the user plane tunnel information corresponding to each bearer in the at least one bearer and the uplink data transmission rules corresponding to each bearer, it can complete the establishment of the uplink user plane tunnel of each bearer on the user plane functional network element corresponding to the PDU session.

[0213] Optionally, in S320, the tunnel information of the PDN connection may also include control plane tunnel information corresponding to the PDN connection.

[0214] Correspondingly, the first control plane functional network element also needs to obtain the control plane tunnel information corresponding to the PDN connection.

[0215] It should be understood that the control plane tunnel corresponding to the PDN connection is used to transmit the control signaling of the PDN connection, that is, the control plane tunnel corresponding to the PDN connection is based on the granularity of the PDN connection.

[0216] Optionally, the first control plane functional network element may obtain the control plane tunnel information corresponding to the PDN connection in a variety of ways, which is not limited in this embodiment of the present application.

[0217] In a possible implementation, when the PDU session is established, the first control plane function network element may allocate control plane tunnel information for the PDN connection.

[0218] Optionally, the control plane tunnel information corresponding to the PDN connection may include the tunnel identifier of the control plane tunnel corresponding to the PDN connection and other information related to the control plane tunnel, such as the Internet Protocol (IP) address corresponding to the control plane tunnel, which is not limited to this embodiment of the present application.

[0219] In the method for switching provided by an embodiment of the present application, the tunnel information corresponding to the PDN connection also includes the control plane tunnel information corresponding to the PDN connection, so that the first control plane functional network element establishes the control plane tunnel corresponding to the PDN connection corresponding to the PDU session, which is beneficial to avoid the loss of control signaling of the PDN connection during network switching, thereby ensuring the normal transmission of control signaling.

[0220] Optionally, in S320, the first control plane function network element may obtain the tunnel information of the PDN connection when the session is established / modified, or the first control plane function network element may obtain the tunnel information of the PDN connection when the switching is prepared.

[0221] In the method for switching provided by an embodiment of the present application, the first control plane function network element obtains the tunnel information of the PDN connection when the PDU session is established or the PDU session is modified or when the switching is prepared, so that the first control plane function network element can establish the user plane tunnel corresponding to the bearer in the PDN connection and the control plane tunnel corresponding to the PDN connection before the switching is performed, which can reduce the delay during the switching process.

[0222] Optionally, the method 300 also includes: the first control plane function network element obtains the bearer identifier corresponding to each bearer in the at least one bearer, so that the first control plane function network element associates the bearer identifier corresponding to each bearer with the user plane tunnel corresponding to each bearer.

[0223] It should be understood that the bearer identifier corresponding to each bearer in the at least one bearer is allocated by the mobility management network element so that the bearer identifier corresponding to each bearer is unique within the PDU session, that is, the bearer identifier corresponding to each bearer can uniquely identify the user plane tunnel corresponding to each bearer.

[0224] In addition, the control plane tunnel information corresponding to the PDN connection can uniquely identify the PDN connection.

[0225] The following will be combined Figure 1 and Figure 2 The application scenario shown in introduces the process of the first control plane function network element obtaining the bearer identifier corresponding to each bearer.

[0226] (1) In Figure 1 In the application scenario shown:

[0227] In one possible implementation, the first control plane function network element may send a bearer identification request to the mobility management network element, and the bearer identification request is used to assign a bearer identification to each bearer in the at least one bearer; accordingly, the mobility management network element receives the bearer identification request from the first control plane function network element, assigns a bearer identification to each bearer according to the bearer identification request, and sends the bearer identification corresponding to each bearer in the at least one bearer to the first control plane function network element.

[0228] It should be noted that the first control plane function network element can save the acquired user plane tunnel information corresponding to each bearer in the at least one bearer, the bearer identifier corresponding to each bearer and the control plane tunnel information corresponding to the PDN connection into the bearer context corresponding to the PDN connection, and send the bearer context to the mobility management network element when switching is prepared.

[0229] Accordingly, the mobility management network element can complete the service gateway (eg, Figure 1 The establishment of an uplink tunnel from the SGW in the PDU session to the user plane functional network element corresponding to the PDU session.

[0230] (2) In Figure 2 In the application scenario shown:

[0231] It should be understood that Figure 2 In the example, the second control plane function network element is the visited control plane network element corresponding to the PDU session, and the first control plane function network element is the home control plane network element corresponding to the PDU session. Therefore, the first control plane function network element needs to obtain the bearer identifier corresponding to each bearer through the second control plane function network element, and the second control plane function network element is responsible for the network switching of the terminal.

[0232] In one possible implementation, the first control plane function network element sends a bearer identification request to the mobility management network element through the second control plane function network element, and the bearer identification request is used to request the allocation of a bearer identification for each bearer in the at least one bearer; the first control plane function network element receives the bearer identification corresponding to each bearer in the at least one bearer from the mobility management network element through the second control plane function network element.

[0233] It should be noted that after the first control plane functional network element obtains the user plane tunnel information corresponding to each bearer in the at least one bearer, the bearer identifier corresponding to each bearer and the control plane tunnel information corresponding to the PDN connection, it can send the user plane tunnel information corresponding to each bearer in the at least one bearer, the bearer identifier corresponding to each bearer and the control plane tunnel information corresponding to the PDN connection to the second control plane functional network element when the PDU session is established / modified.

[0234] Correspondingly, the second control plane function network element can save the user plane tunnel information corresponding to each bearer in the at least one bearer obtained from the first control plane function network element, the bearer identifier corresponding to each bearer and the control plane tunnel information corresponding to the PDN connection into the bearer context of the PDN connection.

[0235] In another possible implementation, the first control plane function network element may send the tunnel information of the PDN connection to the second control plane function network element, and obtain the bearer identifier corresponding to each bearer in the at least one bearer from the second control plane function network element. Accordingly, the second control plane function network element may save the bearer identifier corresponding to each bearer in the at least one bearer.

[0236] That is to say, the first control plane function network element sends the tunnel information of the PDN connection to the second control plane function network element. The second control plane function network element determines whether it is necessary to request the mobility management network element to allocate a bearer identifier for the at least one bearer based on the tunnel information of the PDN connection, and sends a bearer identifier request to the mobility management network element when necessary.

[0237] Specifically, the first control plane function network element will first check whether there is a bearer identifier associated with the user plane tunnel information corresponding to each bearer in the tunnel information of the acquired PDN connection. If some of the at least one bearer are not assigned bearer identifiers, the mobility management network element will be requested to assign bearer identifiers to these bearers.

[0238] It should be noted that the second control plane functional network element can save the user plane tunnel information corresponding to each bearer in the at least one bearer, the bearer identifier corresponding to each bearer and the control plane tunnel information corresponding to the PDN connection into the bearer context of the PDN connection.

[0239] exist Figure 2 In the two implementations of the application scenario shown, since the bearer context corresponding to the PDN connection stored by the second control plane function network element includes the user plane tunnel information corresponding to each bearer in the at least one bearer, the bearer identifier corresponding to each bearer, and the control plane tunnel information corresponding to the PDN connection, the mobility management network element can obtain the bearer context corresponding to the PDN connection from the second control plane function network element during switching preparation, and complete the service gateway (e.g. Figure 1 or Figure 2 The establishment of an uplink tunnel from the SGW in the PDU to the user plane functional network element corresponding to the PDU.

[0240] In the method for switching provided in the embodiment of the present application, since the second control plane functional network element is the control plane network element to which the PDU belongs, the mobility management network element obtains the bearer context corresponding to the PDN connection from the second control plane functional network element compared to obtaining the bearer context corresponding to the PDN connection from the first control plane functional network element, thereby reducing the delay generated during the switching process.

[0241] Optionally, the method 300 also includes: the first control plane functional network element sends the downlink data transmission rule corresponding to the PDN connection to the user plane functional network element corresponding to the PDU session, and the downlink data transmission rule is used to instruct the user plane functional network element corresponding to the PDU session to forward the received downlink data using the corresponding user plane tunnel.

[0242] In one possible implementation, the first control plane function network element may send a third session management request to the user plane function network element corresponding to the PDU session when switching is performed. The third session management request is used to request establishment or modification of a downlink user plane tunnel corresponding to each bearer in the at least one bearer. The third session management request carries the downlink data transmission rule.

[0243] In another possible implementation, the first control plane function network element may carry the downlink data transmission rule and the first rule indication information in the first session management request when requesting / modifying the PDU session, and the first rule indication information is used to indicate that the downlink data transmission rule is not enabled. Accordingly, when the handover is executed, the first control plane function network element sends a third session management request to the user plane function network element corresponding to the PDU session, and the third session management request carries the second rule indication information, and the second rule indication information is used to indicate that the downlink data transmission rule is enabled.

[0244] Optionally, the third session management request may be an N4 session management request, and the third session management response may be an N4 session management response.

[0245] In the method for switching provided by the embodiment of the present application, the first control plane function network element indicates the downlink data transmission rule to the user plane function network element corresponding to the PDU session in the switching execution phase, so that the user plane function network element corresponding to the PDU session matches the received downlink data to the corresponding downlink tunnel according to the downlink data transmission rule and sends it to the service gateway (for example) in the second network through the downlink tunnel. Figure 1 or Figure 2 SGW in the network).

[0246] The following will be combined Figure 4 The function of the second control plane function network element in the above method 300 embodiment is introduced in detail.

[0247] Figure 4 A schematic flow chart of a method 400 for switching provided in an embodiment of the present application is shown. The method 400 can be applied to Figure 2 The method 400 may also be applied to other similar architectures, and the embodiments of the present application are not limited thereto.

[0248] It should be understood that the method 400 may be performed by a second control plane function network element, and the second control plane function network element may be, for example, Figure 2 The v-SMF shown in .

[0249] S410, the second control plane functional network element receives tunnel information of the PDN connection from the first control plane functional network element, the tunnel information of the PDN connection includes user plane tunnel information corresponding to each bearer in at least one bearer, the second control plane functional network element is the visited control plane network element corresponding to the PDU session, and the first control plane functional network element is the home control plane network element corresponding to the PDU session; accordingly, the first control plane functional network element sends the tunnel information of the PDN connection to the second control plane functional network element.

[0250] S420: The second control plane function network element sends the tunnel information of the PDN to the mobility management network element.

[0251] Optionally, the tunnel information of the PDN connection may include control plane tunnel information corresponding to the PDN connection.

[0252] In one possible implementation, the method 400 also includes: the second control plane function network element forwards the bearer identification request sent by the first control plane function to the mobility management network element to the mobility management network element, the bearer identification request is used to request the allocation of a bearer identification for each bearer in the at least one bearer, and forwards the bearer identification corresponding to each bearer in the at least one bearer sent by the mobility management network element to the first control plane function to the first control plane function network element.

[0253] That is to say, the second control plane function network element has the function of transparently transmitting messages transmitted between the first control plane function network element and the user plane function network element corresponding to the PDU session.

[0254] Optionally, the second control plane function network element may also receive a bearer identifier corresponding to each bearer in the at least one bearer from the first control plane function network element.

[0255] In this way, the context corresponding to the PDN connection stored by the second control plane function network element may include the tunnel information of the PDN connection and the bearer identifier corresponding to each bearer in the at least one bearer.

[0256] In another possible implementation, the method 400 also includes: the second control plane function network element sends a bearer identification request to the mobility management network element based on the tunnel information of the PDN connection, and the bearer identification request is used to request the allocation of a bearer identification for each bearer in at least one bearer included in the PDN connection; the second control plane function network element receives the bearer identification corresponding to each bearer in the at least one bearer from the mobility management network element.

[0257] Specifically, the second control plane network element can check whether there is a bearer identifier associated with the user plane tunnel information corresponding to each bearer in the tunnel information of the PDN connection. If it is determined that at least one bearer is not assigned a bearer identifier, the mobility management network element is requested to assign a bearer identifier to each bearer in at least one bearer that is not assigned a bearer identifier.

[0258] That is to say, the second control plane function network element may have a processing function.

[0259] Optionally, the second control plane function network element may save a bearer identifier corresponding to each bearer in the at least one bearer, and send a bearer identifier corresponding to each bearer in the at least one bearer to the first control plane function network element.

[0260] In this way, the context corresponding to the PDN connection stored by the second control plane function network element may include the tunnel information of the PDN connection and the bearer identifier corresponding to each bearer in the at least one bearer.

[0261] The embodiment of the present application provides a method for switching, wherein the bearer context corresponding to the PDN connection stored in the second control plane function network element includes tunnel information of the PDN connection and a bearer identifier corresponding to each bearer in the at least one bearer, so that the mobility management network element can directly obtain the bearer context corresponding to the PDN connection from the second control plane function network element when preparing for switching, and complete the service gateway (for example, Figure 1 or Figure 2The establishment of an uplink tunnel from the SGW in the PDU to the user plane functional network element corresponding to the PDU.

[0262] In addition, since the second control plane functional network element is the control plane network element to which the PDU belongs, the mobility management network element obtains the bearer context corresponding to the PDN connection from the second control plane functional network element compared to obtaining the bearer context corresponding to the PDN connection from the first control plane functional network element, which can reduce the delay generated during the switching process.

[0263] Figure 5 A schematic flow chart of a method 500 for switching provided in an embodiment of the present application is shown. The method 500 can be applied to Figure 1 or Figure 2 The method 500 may also be applied to other similar architectures, and the embodiments of the present application are not limited thereto.

[0264] It should be understood that the method 500 may be executed by a first control plane function network element, and the first control plane function network element may be, for example, Figure 1 or Figure 2 The SMF-PGW-C shown in .

[0265] S510: The first control plane function network element determines that a PDN connection of a terminal in a second network needs to be switched to a PDU session in the first network.

[0266] S520: The first control plane function network element obtains user plane tunnel information corresponding to the PDU session.

[0267] It should be understood that the first network may include a 5G network, and the second network may include a 4G network. It should also be understood that the PDU session in the first network is equivalent to the PDN connection in the second network.

[0268] It should also be understood that the PDU session in the first network is equivalent to the PDN connection in the second network.

[0269] Optionally, in S510, the first control plane functional network element may determine in a variety of ways that the PDN connection of the terminal in the second network needs to be switched to the PDU session in the first network, which is not limited in this embodiment of the present application.

[0270] (1) When a session is established or modified

[0271] In one possible implementation, the first control plane functional network element may receive a third request message, where the third request message is used to request establishment of the PDN connection in the second network; the first control plane functional network element determines, based on the third request message, that the PDN connection of the terminal in the second network needs to be switched to the PDU session in the first network.

[0272] (2) When preparing for switching:

[0273] In one possible implementation, the first control plane function network element may receive a second session management request, the second session management request carrying first indication information, the first indication information being used to indicate preparation for switching the terminal from the second network to the first network; the first control plane function network element may determine, based on the first indication information, that the PDN connection in the second network needs to be switched to the PDU session in the first network.

[0274] Optionally, the first control plane function network element may receive the second session management request from the AMF or receive the second session management request from the v-SMF.

[0275] Optionally, in S520, the first control plane functional network element may obtain the user plane tunnel information corresponding to the PDU session in a variety of ways, which is not limited in this embodiment of the present application.

[0276] In a possible implementation manner, the first control plane function network element may allocate user plane tunnel information corresponding to the PDU session to the PDU session itself.

[0277] In another possible implementation, the first control plane functional network element requests the user plane functional network element corresponding to the PDN connection to allocate user plane tunnel information corresponding to the PDU session, and obtains user plane tunnel information corresponding to the PDU session sent from the user plane functional network element corresponding to the PDN connection.

[0278] In the method for switching provided by an embodiment of the present application, the first control plane functional network element determines that the PDN connection of the terminal in the second network needs to be switched to the PDU session in the first network, and obtains the user plane tunnel information corresponding to the PDU session, so that the first control plane functional network element establishes the user plane tunnel corresponding to the PDU session when the PDN connection is switched to the PDU session, which is beneficial to avoid the loss of data packets in the PDU session during the network switching process, thereby ensuring the normal transmission of data packets.

[0279] It should be understood that the user plane function network element corresponding to the PDN connection may be Figure 1 or Figure 2 UPF+PGW-U in the system architecture shown in .

[0280] Optionally, the method 500 also includes: the first control plane functional network element sends an uplink data transmission rule to the user plane functional network element corresponding to the PDN connection, and the uplink data transmission rule is used to instruct the user plane functional network element corresponding to the PDN connection how to forward the uplink data received through the user plane tunnel corresponding to the PDU session, for example, sending the uplink data packet to an external data network through a specified forwarding path.

[0281] In one possible implementation, the first control plane function network element sends a first session management request to the user plane function network element corresponding to the PDN connection, where the first session management request is used to request establishment or modification of a user plane tunnel corresponding to the PDU session, and the first session management request carries uplink data transmission rules.

[0282] Correspondingly, the user plane function network element corresponding to the PDN connection can receive the first session management request from the first control plane function network element, and send the first session management response to the first control plane function network element according to the first session management request.

[0283] Optionally, the first session management request may be an N4 session management request, and the second session management response may be an N4 session management response.

[0284] It should be understood that in an embodiment of the present application, the N4 session management request may be an N4 session establishment request or an N4 session modification request transmitted through the N4 interface between the first control plane function network element and the user plane function network element corresponding to the PDU session; accordingly, the N4 session management response may be an N4 session establishment response or an N4 session modification response transmitted through the N4 interface between the first control plane function network element and the user plane function network element corresponding to the PDU session.

[0285] Optionally, when the first control plane network element itself allocates user plane tunnel information for the PDU session, the first control plane functional network element may carry the user plane tunnel information corresponding to the PDU session in the first session management request; when the first control plane functional network element requests the user plane functional network element corresponding to the PDN connection to allocate user plane tunnel information for the PDU session, the user plane functional network element corresponding to the PDN connection may carry the user plane tunnel information corresponding to the PDU session in the first session management response.

[0286] Optionally, since the PDN connection in the second network may be updated when the session is modified, such as some new bearers are created, the user plane functional network element corresponding to the PDN connection needs to know the updated uplink data transmission rules in order to associate the data flows corresponding to these bearers with the user plane tunnel corresponding to the PDU session.

[0287] Specifically, in a possible implementation manner, the first control plane function network element may receive a fourth request message from other network elements, where the fourth request message triggers modification of the PDN connection in the second network, for example, adding at least one bearer in the PDN connection;

[0288] In yet another possible implementation, the first control plane function network element may trigger modification of the PDN connection in the second network through its own process.

[0289] Optionally, the method 500 further includes: when the first control plane functional network element determines that the uplink data transmission rule has changed, sending an updated uplink data transmission rule to a user plane functional network element corresponding to the PDN connection.

[0290] Optionally, when the first control plane functional network element allocates user plane tunnel information for the PDU session by itself, the first control plane functional network element can obtain the user plane tunnel information corresponding to the PDU session in the same stage, and send the user plane tunnel information corresponding to the PDU session to the user plane functional network element corresponding to the PDN connection, or obtain the user plane tunnel information corresponding to the PDU session at different stages, and send the user plane tunnel information corresponding to the PDU session to the user plane functional network element corresponding to the PDN connection. The embodiments of the present application are not limited to this.

[0291] In one possible implementation, the first control plane functional network element can obtain the user plane tunnel information and the uplink data transmission rules corresponding to the PDU session when the session is established / modified, and send the user plane tunnel information and the uplink data transmission rules corresponding to the PDU session to the user plane functional network element corresponding to the PDN connection.

[0292] In another possible implementation, the first control plane functional network element can obtain the user plane tunnel information and the uplink data transmission rules corresponding to the PDU session when preparing for network switching, and send the user plane tunnel information and the uplink data transmission rules corresponding to the PDU session to the user plane functional network element corresponding to the PDN connection.

[0293] In another possible implementation, the first control plane functional network element can obtain the user plane tunnel information and the uplink data transmission rules corresponding to the PDU session when the session is established / modified, and send the user plane tunnel information and the uplink data transmission rules corresponding to the PDU session to the user plane functional network element corresponding to the PDN connection when the network switching is prepared.

[0294] In the method for switching provided by the embodiment of the present application, the first control plane functional network element determines and sends the user plane tunnel information corresponding to the PDU session to the user plane functional network element corresponding to the PDN connection during the switching preparation stage, thereby avoiding the update of the uplink data transmission rules due to the newly added bearer when the session is established / modified.

[0295] Optionally, the method 500 also includes: the first control plane functional network element sends the downlink data transmission rules corresponding to the PDU session to the user plane functional network element corresponding to the PDN connection, and the downlink data transmission rules are used to indicate that the downlink data packet received by the user plane functional network element corresponding to the PDN connection is sent through the user plane tunnel corresponding to the PDU session.

[0296] In one possible implementation, the first control plane function network element may send a third session management request to the user plane function network element corresponding to the PDN connection when switching is performed, and the third session management request is used to request modification of the downlink user plane tunnel corresponding to the PDU session, and the third session management request carries the downlink data transmission rule.

[0297] In another possible implementation, the first control plane function network element may carry the downlink data transmission rule and the first rule indication information in the first session management request when the session is established / modified, and the first rule indication information is used to indicate that the downlink data transmission rule is not enabled. Accordingly, when the handover is executed, the first control plane function network element sends a third session management request to the user plane function network element corresponding to the PDN connection, and the third session management request carries the second rule indication information, and the second rule indication information is used to indicate that the downlink data transmission rule is enabled.

[0298] Optionally, the third session management request may be an N4 session management request, and the third session management response may be an N4 session management response.

[0299] In the method for switching provided in the embodiment of the present application, the first control plane function network element indicates a downlink data transmission rule to the user plane function network element corresponding to the PDN connection during the switching execution phase, so that the user plane function network element corresponding to the PDN connection matches the received downlink data to the corresponding downlink tunnel according to the downlink data transmission rule and sends it to the V-UPF or access network (for example) in the first network through the downlink tunnel. Figure 1 or Figure 2 V-UPF or access network in the network).

[0300] Figure 6 A schematic flow chart of a method 600 for switching provided in an embodiment of the present application is shown. The method 600 can be applied to Figure 1In the system architecture in the non-roaming scenario shown, or, the method 600 can also be applied to other similar architectures.

[0301] It should be understood that the method 600 is divided into three phases: session establishment / modification phase, handover preparation phase and handover execution phase. Figure 6 The above three stages are introduced in detail.

[0302] First, session establishment / modification phase:

[0303] It should be noted that S601 to S602 are the processes for SMF+PGW-C to determine at least one bearer that needs to be established when the PDU session of the terminal in the first network is switched to the PDN connection of the second network.

[0304] S601, SMF+PGW-C receives a session establishment / modification request from AMF, and the session establishment / modification request is used to request to establish a PDU session of the terminal in the first network or trigger modification of the PDU session in the first network; accordingly, the AMF sends the session establishment / modification request to the SMF+PGW-C.

[0305] S602, the SMF+PGW-C determines at least one bearer that needs to be established when the PDU session of the terminal in the first network switches to the packet data network PDN connection in the second network according to the session establishment / modification request in S601.

[0306] It should be noted that S603a~S605a or S603b~S605b is the process for the SMF+PGW-C and the UPF+PGW-U to establish a user plane tunnel corresponding to each bearer for each bearer in the at least one bearer.

[0307] It should be understood that the SMF+PGW-C and the UPF+PGW-U establish a user plane tunnel corresponding to each bearer in the at least one bearer, which may include the SMF+PGW-C and the UPF+PGW-U obtaining the user plane tunnel information corresponding to each bearer and the uplink data packet transmission rule.

[0308] Optionally, the user plane tunnel information corresponding to each bearer in the at least one bearer can be allocated by the SMF+PGW-C or by the UPF+PGW-U, which is not limited to the embodiments of the present application.

[0309] Among them, if the user plane tunnel information is allocated by the SMF+PGW-C, S603a~S605a are executed; if the user plane tunnel information is allocated by the UPF+PGW-U, S603b~S605b are executed.

[0310] (1) The SMF+PGW-C allocates user plane tunnel information for each bearer.

[0311] S603a, the SMF+PGW-C allocates user plane tunnel information for each bearer.

[0312] S604a, the SMF+PGW-C sends an N4 session establishment / modification request to the UPF+PGW-U, the N4 session establishment / modification request is used to request the establishment of a user plane tunnel corresponding to each bearer in the at least one bearer, and the N4 session establishment / modification request carries the user plane tunnel information corresponding to each bearer and the uplink data packet transmission rule, the uplink data transmission rule is used to indicate the user plane function network element corresponding to the PDU session (such as Figure 6 How does the UPF+PGW-U in forward the uplink data received through the user plane tunnel corresponding to the PDN connection; accordingly, the UPF+PGW-U receives the N4 session establishment / modification request from the SMF+PGW-C.

[0313] S605a, the UPF+PGW-U sends an N4 session establishment / modification response to the SMF+PGW-C according to the N4 session establishment / modification request received in S604a; accordingly, the SMF+PGW-C receives the N4 session establishment / modification response from the UPF+PGW-U.

[0314] (2) The UPF+PGW-U allocates user plane tunnel information for each bearer.

[0315] S603b, the SMF+PGW-C sends an N4 session establishment / modification request to the UPF+PGW-U, the N4 session establishment / modification request is used to request the establishment of a user plane tunnel corresponding to each bearer in the at least one bearer, and the N4 session establishment / modification request carries an uplink data packet transmission rule, the uplink data transmission rule is used to indicate the user plane function network element corresponding to the PDU session (such as Figure 6 How the UPF+PGW-U) in the PDN connection forwards the uplink data received through the user plane tunnel corresponding to the PDN connection; accordingly, the UPF+PGW-U receives the N4 session establishment / modification request from the SMF-PGW-C.

[0316] S604b, the UPF+PGW-U allocates user plane tunnel information for each bearer according to the N4 session establishment / modification request received in S603b.

[0317] S605b, the UPF+PGW-U sends an N4 session establishment / modification response to the SMF+PGW-C, and the N4 session establishment / modification response carries the user plane tunnel information corresponding to each bearer; accordingly, the SMF+PGW-C receives the N4 session establishment / modification response from the UPF+PGW-U.

[0318] After S603a or S605b, the SMF-PGW-C saves the user plane tunnel information corresponding to each bearer in the at least one bearer and the uplink data transmission rule to the bearer context corresponding to the PDN connection.

[0319] It should also be understood that the user plane tunnel information corresponding to each bearer may include an identifier of the user plane tunnel corresponding to each bearer.

[0320] Optionally, the user plane tunnel information corresponding to each bearer may also include the Internet Protocol (IP) address of the user plane tunnel corresponding to each bearer, or other information of the user plane tunnel corresponding to each bearer, which is not limited to the embodiments of the present application.

[0321] It should be noted that S606 is the process for the SMF-PGW-C to establish a control plane tunnel corresponding to the PDN connection for the PDN connection.

[0322] It should be understood that the SMF+PGW-C establishes a control plane tunnel corresponding to the PDN connection for the PDN connection, which can be understood as the SMF+PGW-C allocates the control plane tunnel information corresponding to the PDN connection to the PDN connection.

[0323] S606, the SMF+PGW-C obtains the control plane tunnel information corresponding to the PDN connection.

[0324] After S606, the SMF-PGW-C saves the control plane tunnel information corresponding to the PDN connection to the bearer context corresponding to the PDN connection.

[0325] It should be understood that since the control plane tunnel corresponding to the PDN connection is used to transmit the control signaling of the PDN connection to the UPF+PGW-U, that is, the control plane tunnel corresponding to the PDN connection is based on the granularity of the PDN connection, S606 is only executed in the session establishment stage, that is, S606 is not executed in the session modification stage.

[0326] It should also be understood that the control plane tunnel information corresponding to the PDN connection may include an identifier of the control plane tunnel corresponding to the PDN connection.

[0327] Optionally, the control plane tunnel information corresponding to the PDN connection may also include an Internet Protocol (IP) address of the control plane tunnel corresponding to the PDN connection, or other information of the control plane tunnel corresponding to the PDN connection, which is not limited in the embodiments of the present application.

[0328] It should be noted that S607 to S609 are the process for the SMF+PGW-C to obtain the bearer identifier corresponding to each bearer in the at least one bearer.

[0329] S607, the SMF+PGW-C sends a bearer update request to the AMF, where the bearer update request is used to request the bearer identifier corresponding to each bearer in the at least one bearer; accordingly, the AMF receives the bearer update request from the SMF+PGW-C.

[0330] S608: The AMF allocates a bearer identifier to each of the at least one bearer according to the bearer update request.

[0331] S609, the AMF sends a bearer update response to the SMF+PGW-C, and the bearer update response carries the bearer identifier corresponding to each bearer in the at least one bearer; accordingly, the SMF+PGW-C receives the bearer update response from the AMF.

[0332] After S609, the SMF-PGW-C saves the bearer identifier of each bearer in the at least one bearer to the bearer context corresponding to the PDN connection.

[0333] It should be understood that the bearer identifier of each bearer may identify the user plane tunnel corresponding to each bearer.

[0334] Optionally, the execution order of the process described in S603a~S605a (or S603b~S605b), the process described in S606, and the process described in S607~S609 is not specific, and this embodiment of the application does not limit this.

[0335] To summarize, after S601a (or S601b) to S609, the bearer context corresponding to the PDN connection saved by the SMF+PGW-C may include the control plane tunnel information corresponding to the PDN connection, the user plane tunnel information corresponding to each bearer in the at least one bearer, and the bearer identifier corresponding to each bearer in the at least one bearer.

[0336] Optionally, the bearer context corresponding to the PDN connection may also include other information required in the subsequent switching preparation stage and the switching execution stage, for example, the QoS parameters of each bearer, wherein the QoS parameters of each bearer include at least one of a QoS class identifier (QCI), an allocation and retention priority (ARP), a packet filter and a priority of a packet filter, and the embodiments of the present application are not limited to this.

[0337] Second, the switching preparation stage:

[0338] S610, the AMF accesses the source access network of the first network (such as Figure 6 The gNB in ​​the handover request receives the handover request, which carries the target access network (such as Figure 6 Accordingly, the source access network sends the switching request to the AMF.

[0339] S611, the AMF determines, based on the information of the target access network, that the terminal will switch from the first network to the second network.

[0340] S612, the AMF sends a bearer context request to the SMF+PGW-C, where the bearer context request is used to request the bearer context corresponding to the PDN connection; accordingly, the SMF+PGW-C receives the bearer context request from the AMF.

[0341] S613, the SMF+PGW-C sends the bearer context corresponding to the PDN connection to the AMF according to the bearer context request; accordingly, the AMF receives the bearer context corresponding to the PDN connection from the SMF+PGW-C.

[0342] S614, the AMF sends the bearer context corresponding to the PDN connection to the MME in the second network; accordingly, the MME receives the bearer context corresponding to the PDN connection from the AMF.

[0343] S615: The MME obtains tunnel information of the PDN connection from the bearer context corresponding to the PDN connection.

[0344] S616, the MME sends the tunnel information of the PDN connection to the SGW in the second network; correspondingly, the SGW receives the tunnel information of the PDN connection from the MME.

[0345] It should also be understood that the user plane tunnel and control plane tunnel described in the above session establishment / modification phase and switching preparation phase refer to the uplink user plane tunnel on PGW-U+UPF and the uplink control plane tunnel on PGW-C+SMF.

[0346] It should be noted that after S610 to S616, the uplink tunnel from the SGW to the UPF+PGW-U is established. When the terminal switches from the source access network in the first network to the target access network in the second network, the uplink data can be seamlessly switched to be sent to the data network through the uplink tunnel from the SGW to the UPF+PGW-U.

[0347] It should be understood that the switching preparation stage in the method 600 is not limited to the above process, but may also include other processes (for example, reference may be made to the process in the switching preparation stage in the prior art), and the embodiments of the present application are not limited thereto.

[0348] Third, switch execution phase:

[0349] S617, when the terminal accesses the second network through the target access network, the target access network sends a switching notification to the MME, where the switching notification is used to notify the terminal that the terminal has switched from the first network to the second network; accordingly, the MME receives the switching notification.

[0350] S618, the MME sends a bearer modification request to the SGW, and the bearer modification request carries the downlink tunnel information of the access network. The downlink tunnel information of the access network includes the downlink user plane tunnel information corresponding to each bearer in the at least one bearer on the access network; accordingly, the SGW receives the bearer modification request from the MME.

[0351] S619, the SGW sends a bearer modification request to the SMF+PGW-C through the control plane tunnel corresponding to the PDN connection according to the bearer modification request in S618, and the bearer modification request carries the downlink tunnel information of the SGW, and the downlink tunnel information of the SGW includes the downlink user plane tunnel information corresponding to each bearer of the at least one bearer on the SGW; accordingly, the SMF+PGW-C receives the bearer modification request from the SGW through the control plane tunnel corresponding to the PDN connection.

[0352] S620: The SMF+PGW-C determines, based on the message sent by the SGW, that the terminal has switched to the second network.

[0353] S621, the SMF+PGW-C sends an N4 session establishment / modification request to the UPF+PGW-U, and the N4 session establishment / modification request carries the downlink tunnel information and downlink data transmission rules on the SGW, and the downlink data transmission rules are used to instruct the user plane function network element corresponding to the PDU session to forward the received downlink data to the SGW using the corresponding user plane tunnel; accordingly, the UPF+PGW-U receives the N4 session establishment / modification request from the SMF+PGW-C.

[0354] S622, the UPF+PGW-U sends an N4 session establishment / modification response to the SMF+PGW-C according to the N4 session establishment / modification request received in S621; accordingly, the SMF+PGW-C receives the N4 session establishment / modification response from the UPF+PGW-U.

[0355] Optionally, the third session management request may be carried in a second N4 session modification request sent by the SMF+PGW-C to the UPF+PGW-U through the N4 interface, and the third session management response may be carried in a second N4 session modification response sent by the UPF+PGW-U to the SMF+PGW-C through the N4 interface. This embodiment of the present application is not limited to this.

[0356] In one possible implementation, the N4 session establishment / modification request in S621 may not carry the downlink data transmission rule, and the downlink data transmission rule may be carried in the N4 session establishment / modification request in S604a or S603b, and the N4 session establishment / modification request in S604a or S603b may also carry first rule indication information, and the first rule indication information is used to indicate that the downlink data transmission rule is not enabled.

[0357] Correspondingly, the N4 session establishment / modification request in S621 may carry second rule indication information, where the second rule indication information is used to indicate the activation of the downlink data packet transmission rule; the UPF+PGW-U activates the downlink data packet transmission rule according to the second rule indication information.

[0358] To sum up, after S622, the downlink tunnel from UPF+PGW-U to SGW is established. After the terminal switches to the second network, the downlink data in the data network can be switched to be sent to the target access network through the user plane tunnel from UPF+PGW-U to the SGW.

[0359] Figure 7 A schematic flow chart of a method 700 for switching provided in an embodiment of the present application is shown. The method 700 can be applied to Figure 2 In the system architecture in the roaming scenario shown, or, the method 700 can also be applied to other similar architectures.

[0360] It should be understood that the method 700 is divided into three phases: session establishment / modification phase, handover preparation phase and handover execution phase. Figure 7 The above three stages are introduced in detail.

[0361] First, session establishment / modification phase:

[0362] It should be noted that S701 to S702 are the processes for SMF+PGW-C to determine at least one bearer that needs to be established when the PDU session of the terminal in the first network is switched to the PDN connection of the second network.

[0363] S701~S702 are similar to S601~S602.

[0364] It should be noted that S703a~S705a or S703b~S705b is the process for the SMF+PGW-C and the UPF+PGW-U to establish a user plane tunnel corresponding to each bearer in the at least one bearer.

[0365] S703a~S705a are similar to S603a~S605a.

[0366] S703b~S705b are similar to S603b~S605b.

[0367] After S703a or S705b, the SMF-PGW-C saves the user plane tunnel information corresponding to each bearer in the at least one bearer to the bearer context corresponding to the PDN connection.

[0368] It should be noted that S706 is the process for the SMF-PGW-C to establish a control plane tunnel corresponding to the PDN connection for the PDN connection.

[0369] S706, similar to S606.

[0370] After S706, the SMF-PGW-C saves the control plane tunnel information corresponding to the PDN connection to the bearer context corresponding to the PDN connection.

[0371] It should be understood that since the control plane tunnel corresponding to the PDN connection is used to transmit the control signaling of the PDN connection to the UPF+PGW-U, that is, the control plane tunnel corresponding to the PDN connection is based on the granularity of the PDN connection, S706 is only executed in the session establishment stage, that is, S706 is not executed in the session modification stage.

[0372] It should be noted that S707 to S709 are the process for the SMF+PGW-C to obtain the bearer identifier corresponding to each bearer in the at least one bearer.

[0373] S707, the SMF+PGW-C sends a bearer update request to the AMF through the v-SMF, and the bearer update request is used to request the bearer identifier corresponding to each bearer in the at least one bearer; accordingly, the AMF receives the bearer update request from the SMF+PGW-C through the v-SMF.

[0374] It should be understood that in S707, the v-SMF only provides a message delivery function, that is, forwarding the message sent by the SMF+PGW-C to the AMF to the AMF.

[0375] Specifically, v-SMF can send the message sent by SMF+PGW-C to AMF to the corresponding AMF according to the identifier of the terminal, and send the message sent by AMF to SMF+PGW-C to the corresponding SMF+PGW-C according to the identifier of the PDU session and the identifier of the terminal.

[0376] S708, similar to S608.

[0377] S709, the AMF sends a bearer update response to the SMF+PGW-C through the v-SMF, and the bearer update response carries the bearer identifier corresponding to each bearer in the at least one bearer; accordingly, the SMF+PGW-C receives the bearer update response from the AMF through the v-SMF.

[0378] It should be understood that in S709, the v-SMF only provides a message delivery function, that is, forwarding the message sent by the AMF to the SMF+PGW-C to the SMF+PGW-C.

[0379] After S709, the SMF+PGW-C saves the bearer identifier of each bearer in the at least one bearer to the bearer context corresponding to the PDN connection.

[0380] S710, the SMF+PGW-C sends the bearer context corresponding to the PDN connection to the v-SMF, where the bearer context corresponding to the PDN connection includes the control plane tunnel information corresponding to the PDN connection, the user plane tunnel information corresponding to each bearer in the at least one bearer, and the bearer identifier corresponding to each bearer in the at least one bearer.

[0381] After S710, the v-SMF saves the bearer context corresponding to the PDN connection.

[0382] Optionally, since the control plane tunnel corresponding to the PDN connection is used to transmit the control signaling of the PDN connection to the UPF+PGW-U, that is, the control plane tunnel corresponding to the PDN connection is based on the granularity of the PDN connection, only the bearer context corresponding to the PDN connection in the session establishment phase S710 includes the control plane tunnel corresponding to the PDN connection, that is, the bearer context corresponding to the PDN connection sent by the SMF+PGW-C to the v-SMF in the session modification phase S710 does not include the control plane tunnel corresponding to the PDN connection. In fact, step 710 of the session modification phase is an update of the bearer context corresponding to the PDN connection, that is, the bearer context corresponding to the PDN connection includes the bearer identifier of the newly added bearer and the corresponding user plane tunnel information.

[0383] Optionally, the execution order of the processes described in 703a to 705a (or 703b to 705b), the process described in S706, and the process described in S707 to S709 is not specific, and this embodiment of the application does not limit this.

[0384] It should be noted that if the process described in 703a~705a (or 703b~705b) is executed before the process described in S707~S709, then in S709, after SMF+PGW-C receives the bearer identification response, if the allocation of the bearer identification requested by a certain bearer fails, SMF+PGW-C sends a message to PGW-U+UPF to delete the user plane tunnel corresponding to the bearer.

[0385] To summarize, after S701 to S710, the bearer context corresponding to the PDN connection saved by the v-SMF and the SMF-PGW-C may include the control plane tunnel information corresponding to the PDN connection, the user plane tunnel information corresponding to each bearer in the at least one bearer, and the bearer identifier corresponding to each bearer in the at least one bearer.

[0386] Optionally, the SMF+PGW-C may also send other information required in the subsequent switching preparation phase and switching execution phase to the v-SMF, for example, the QoS parameters of each bearer, wherein the QoS parameters of each bearer include at least one of a QoS class identifier (QoS class identifier, QCI), an allocation and retention priority (allocation retention priority, ARP), a packet filter, and a priority of a packet filter. Accordingly, the v-SMF receives this information from the SMF+PGW-C and saves this information to the bearer context corresponding to the PDN connection. This embodiment of the present application is not limited to this.

[0387] Second, the switching preparation stage:

[0388] S711~S712 are similar to S610~S611.

[0389] S713, the AMF sends a bearer context request to the v-SMF, where the bearer context request is used to request the bearer context corresponding to the PDN connection; accordingly, the v-SMF receives the bearer context request from the AMF.

[0390] S714, the v-SMF sends the bearer context corresponding to the PDN connection to the AMF according to the bearer context request; accordingly, the AMF receives the bearer context corresponding to the PDN connection from the v-SMF.

[0391] S715~S717 are similar to S614~S616.

[0392] It should be understood that the switching preparation stage in method 700 is not limited to the above-mentioned process, and may also include other processes (for example, reference may be made to the process in the switching preparation stage in the prior art), and the embodiments of the present application are not limited thereto.

[0393] Third, the switching execution phase: the same as the switching execution phase in method 600 .

[0394] It should be noted that the v-SMF in the method 700 has the function of transparently transmitting messages between the SMF+PGW-C and the AMF.

[0395] Figure 8 A schematic flow chart of a method 800 for switching provided in an embodiment of the present application is shown. The method 800 can be applied to Figure 2 In the system architecture in the roaming scenario shown, or, the method 800 can also be applied to other similar architectures.

[0396] It should be understood that the first network may include a 5G network, and the second network may include a 4G network, which is not limited in this embodiment of the present application.

[0397] It should also be understood that the method 800 is divided into three phases: session establishment / modification phase, handover preparation phase, and handover execution phase. Figure 8 The above three stages are introduced in detail.

[0398] First, session establishment / modification phase:

[0399] It should be noted that S801 to S802 are the processes for SMF+PGW-C to determine at least one bearer that needs to be established when the PDU session of the terminal in the first network is switched to the PDN connection of the second network.

[0400] S801~S802 are similar to S601~S602.

[0401] It should be noted that S803a~S805a or S803b~S805b is the process for the SMF+PGW-C and the UPF+PGW-U to establish a user plane tunnel corresponding to each bearer for each bearer in the at least one bearer.

[0402] S803a~S805a are similar to S603a~S605a.

[0403] S803b~8805b are similar to S603b~S605b.

[0404] After S803a or S805b, the SMF-PGW-C saves the user plane tunnel information corresponding to each bearer in the at least one bearer and the uplink data transmission rule to the bearer context corresponding to the PDN connection.

[0405] It should be noted that S806 is the process for the SMF-PGW-C to establish a control plane tunnel corresponding to the PDN connection for the PDN connection.

[0406] S806, similar to S606.

[0407] After S806, the SMF-PGW-C saves the control plane tunnel information corresponding to the PDN connection to the bearer context corresponding to the PDN connection.

[0408] It should be understood that since the control plane tunnel corresponding to the PDN connection is used to transmit the control signaling of the PDN connection to the UPF+PGW-U, that is, the control plane tunnel corresponding to the PDN connection is based on the granularity of the PDN connection, S806 is only executed in the session establishment stage, that is, S806 is not executed in the session modification stage.

[0409] It should be noted that S807 to S811 are the process for the SMF+PGW-C to obtain the bearer identifier corresponding to each bearer in the at least one bearer.

[0410] S807, the SMF+PGW-C sends the tunnel information of the PDN connection to the v-SMF, the tunnel information of the PDN connection includes the control plane tunnel information corresponding to the PDN connection and the user plane tunnel information corresponding to each bearer in the at least one bearer; accordingly, the v-SMF receives the tunnel information of the PDN connection from the SMF+PGW-C.

[0411] Optionally, since the control plane tunnel corresponding to the PDN connection is used to transmit the control signaling of the PDN connection to the UPF+PGW-U, that is, the control plane tunnel corresponding to the PDN connection is based on the granularity of the PDN connection, only the bearer context corresponding to the PDN connection in the session establishment phase S807 includes the control plane tunnel corresponding to the PDN connection, that is, the tunnel information of the PDN connection sent by the SMF+PGW-C to the v-SMF in the session modification phase S807 does not include the control plane tunnel corresponding to the PDN connection. In fact, step 807 of the session modification phase is an update of the bearer context corresponding to the PDN connection, that is, the tunnel information corresponding to the PDN connection includes the bearer identifier of the newly added bearer and the corresponding user plane tunnel information.

[0412] After S807, the v-SMF saves the user plane tunnel information corresponding to each bearer and the control plane tunnel information corresponding to the PDN connection into the bearer context corresponding to the PDN connection.

[0413] S808, the v-SMF sends a bearer identification request to the AMF according to the tunnel information of the PDN connection received in S807, and the bearer identification request is used to request the allocation of a bearer identification for each bearer in at least one bearer received in S807; accordingly, the AMF receives the bearer identification request from the v-SMF.

[0414] S809: The AMF allocates user plane tunnel information to each bearer in the at least one bearer according to the bearer identification request.

[0415] S810, the AMF sends bearer identification information to the v-SMF, where the bearer identification information includes a bearer identification corresponding to each bearer in the at least one bearer; accordingly, the v-SMF receives the bearer identification information from the AMF.

[0416] After S810, the v-SMF saves the bearer identifier of each bearer into the bearer context corresponding to the PDN connection.

[0417] It should be noted that S811 is the process for the SMF+PGW-C to obtain the bearer identifier of each bearer.

[0418] S811, the v-SMF sends the bearer identification information to the SMF-PGW-C; correspondingly, the SMF+PGW-C receives the bearer identification information from the v-SMF.

[0419] Specifically, v-SMF sends the bearer identifier corresponding to each bearer and the user plane tunnel information corresponding to each bearer to SMF+PGW-C, so that SMF+PGW-C can associate the bearer identifier corresponding to each bearer with the user plane tunnel information.

[0420] After S811, the SMF-PGW-C saves the bearer identifier corresponding to each bearer in the at least one bearer to the bearer context corresponding to the PDN connection.

[0421] Optionally, the execution order of the process described in S803a~S805a (or S803b~S805b) and the process described in S806 is not specific, and this embodiment of the application does not limit this.

[0422] To summarize, after S801 to S811, the bearer context corresponding to the PDN connection saved by the v-SMF and the SMF-PGW-C may include the control plane tunnel information corresponding to the PDN connection, the user plane tunnel information corresponding to each bearer and the bearer identifier of each bearer, and the bearer context corresponding to the PDN connection is used to switch the terminal from the first network to the second network.

[0423] Optionally, the SMF+PGW-C may also send other information required in the subsequent switching preparation phase and switching execution phase to the v-SMF, for example, the QoS parameters of each bearer, wherein the QoS parameters of each bearer include at least one of a QoS class identifier (QoS class identifier, QCI), an allocation and retention priority (allocation retention priority, ARP), a packet filter, and a priority of a packet filter. Accordingly, the v-SMF receives this information from the SMF+PGW-C and saves this information to the bearer context corresponding to the PDN connection. This embodiment of the present application is not limited to this.

[0424] Second, the switching preparation phase: the same as the switching preparation phase in method 700 .

[0425] Third, the switching execution phase: Figure 6 The switching execution phase in .

[0426] It should be noted that the v-SMF in the method 800 has a processing function.

[0427] Specifically, the v-SMF can check whether there is a bearer identifier associated with the user plane tunnel information corresponding to each bearer in the tunnel information of the PDN connection. If it is determined that at least one bearer is not assigned a bearer identifier, the AMF is requested to assign a bearer identifier to each of the at least one bearer.

[0428] Combined with the above Figures 6 to 8The present invention provides a method for switching, wherein the SMF-PGW-C or v-SMF obtains tunnel information of the PDN connection during the session establishment / modification phase. Figures 9 to 11 Introduce that the SMF-PGW-C or v-SMF obtains the tunnel information of the PDN connection during the switching preparation phase.

[0429] Fig. 9 A schematic flow chart of a method 900 for switching provided in an embodiment of the present application is shown. The method 900 can be applied to Figure 1 In the system architecture in the non-roaming scenario shown, or, the method 900 can also be applied to other similar architectures.

[0430] It should be understood that the first network may include a 5G network, and the second network may include a 4G network, which is not limited in this embodiment of the present application.

[0431] It should also be understood that the method 900 is divided into three phases: a session establishment / modification phase, a handover preparation phase, and a handover execution phase. The above three phases will be described in detail below.

[0432] First, the session modification stage:

[0433] It should be noted that S901 to S902 are the processes for SMF+PGW-C to determine at least one bearer that needs to be established when the PDU session of the terminal in the first network is switched to the PDN connection of the second network.

[0434] S901~S902 are similar to S601~S602.

[0435] It should be noted that S903 to S905 are the process for the SMF+PGW-C to obtain the bearer identifier corresponding to each bearer in the at least one bearer.

[0436] S903~S905 are similar to S607~S609.

[0437] After S905, the SMF-PGW-C saves the bearer identifier corresponding to each bearer in the bearer context corresponding to the PDN connection.

[0438] To summarize, after S905, the bearer context corresponding to the PDN connection saved by the SMF+PGW-C may include the bearer identifier corresponding to each bearer.

[0439] Second, the switching preparation stage:

[0440] It should be understood that S906 to S908 are similar to S610 to S612 and will not be described in detail here.

[0441] It should be noted that S909a~S911a or S909b~S911b is the process for the SMF+PGW-C and the UPF+PGW-U to establish the user plane tunnel corresponding to each bearer for each bearer.

[0442] It should be understood that S909a to S911a are similar to S603a to S605a, and S909b to S911b are similar to S603b to S605b, which will not be described in detail here.

[0443] After S909a or S911b, the SMF-PGW-C saves the user plane tunnel information corresponding to each bearer into the bearer context corresponding to the PDN connection.

[0444] It should be noted that S912 is the process for the SMF-PGW-C to establish a control plane tunnel corresponding to the PDN connection for the PDN connection.

[0445] It should be understood that S912 is the same as S606.

[0446] After S912, the SMF-PGW-C saves the control plane tunnel information corresponding to the PDN connection to the bearer context corresponding to the PDN connection.

[0447] It should be understood that the subsequent S913 to S916 are similar to S613 to S616 and will not be described in detail here.

[0448] To sum up, after S916, the uplink tunnel from the SGW to the UPF+PGW-U is established. When the terminal switches from the source access network in the first network to the target access network in the second network, the uplink data can be seamlessly switched to be sent to the data network through the uplink tunnel from the SGW to the UPF+PGW-U.

[0449] Third, the switching execution phase: Figure 6 The switching execution phase in .

[0450] Fig.10 A schematic flow chart of a method 1000 for switching provided in an embodiment of the present application is shown. The method 1000 can be applied to the system architecture in the roaming scenario shown in the figure, or the method 1000 can also be applied to other similar architectures.

[0451] It should be understood that the first network may include a 5G network, and the second network may include a 4G network, which is not limited in this embodiment of the present application.

[0452] It should also be understood that the method 1000 is divided into three phases: a session establishment / modification phase, a handover preparation phase, and a handover execution phase. The above three phases will be described in detail below.

[0453] First, session establishment / modification phase:

[0454] It should be noted that S1001 to S1002 are the processes for SMF+PGW-C to determine at least one bearer that needs to be established when the PDU session of the terminal in the first network is switched to the PDN connection of the second network.

[0455] S1001~S1001 are similar to S601~S602.

[0456] It should be noted that S1003 to S1005 are the process for the PGW-C+SMF to obtain the bearer identifier corresponding to each bearer.

[0457] S1003~S1005 are similar to S707~S709.

[0458] After S1005, the SMF-PGW-C saves the bearer identifier corresponding to each bearer in the bearer context corresponding to the PDN connection.

[0459] Second, the switching preparation stage:

[0460] It should be understood that S1006 to S1007 are similar to S610 to S611 and will not be described in detail here.

[0461] S1008, the AMF sends a bearer context request to the SMF+PGW-C through the v-SMF, and the bearer context request is used to request the bearer context corresponding to the PDN connection; accordingly, the SMF+PGW-C receives the bearer context request from the AMF through the v-SMF.

[0462] It should be understood that in S1008, the v-SMF only provides a message delivery function, that is, forwarding the message sent by the AMF to the SMF+PGW-C to the SMF+PGW-C.

[0463] It should be noted that S1009a~S1011a or S1009b~S1011b is the process for the SMF+PGW-C and the UPF+PGW-U to establish the user plane tunnel corresponding to each bearer for each bearer.

[0464] It should be understood that S1009a to S1011a are similar to S603a to S605a, and S1009b to S1011b are similar to S603b to S605b, which will not be described in detail here.

[0465] After S1009a or S10010b, the SMF-PGW-C saves the user plane tunnel information corresponding to each bearer into the bearer context corresponding to the PDN connection.

[0466] It should be noted that S1012 is the process for the SMF-PGW-C to establish a control plane tunnel corresponding to the PDN connection for the PDN connection.

[0467] After S1012, the SMF-PGW-C saves the control plane tunnel information corresponding to the PDN connection to the bearer context corresponding to the PDN connection.

[0468] S1013, the SMF+PGW-C sends the bearer context corresponding to the PDN connection to the AMF through the v-SMF; accordingly, the AMF receives the bearer context corresponding to the PDN connection from the SMF+PGW-C. It should be understood that in S1013, the v-SMF only provides a message delivery function, that is, forwarding the message sent by the SMF+PGW-C to the AMF to the AMF.

[0469] It should be understood that subsequent S1014 to S1016 are similar to S614 to S616 and will not be described in detail here.

[0470] To sum up, after S1016, the uplink tunnel from the SGW to the UPF+PGW-U is established. When the terminal switches from the source access network in the first network to the target access network in the second network, the uplink data can be seamlessly switched to be sent to the data network through the uplink tunnel from the SGW to the UPF+PGW-U.

[0471] Third, the switching execution phase: Figure 6 The switching execution phase in .

[0472] Combined with the above Figures 6 to 10 The process of switching from a 5G network to a 4G network is described below. Fig.11 and Fig.12 This section describes the process of switching a terminal from a 4G network to a 5G network.

[0473] Fig.11 A schematic flow chart of a method 1100 for switching provided in an embodiment of the present application is shown. The method 1100 can be applied to Figure 1 In the system architecture in the non-roaming scenario shown, or, the method 1100 can also be applied to other similar architectures.

[0474] It should be understood that the first network may include a 5G network, and the second network may include a 4G network, which is not limited in this embodiment of the present application.

[0475] It should also be understood that since there is no control plane tunnel corresponding to the PDU session in the first network, the tunnel corresponding to the PDU session described in the embodiments of the present application refers to the user plane tunnel corresponding to the PDU session, and the tunnel information corresponding to the PDU session refers to the user plane tunnel information corresponding to the PDU session.

[0476] S1101, SMF+PGW-C receives a session establishment / modification request from AMF, where the session establishment / modification request is used to request establishment of a PDN connection in the second network or trigger modification of the PDN connection in the second network; accordingly, the AMF sends the session establishment / modification request to the SMF+PGW-C.

[0477] S1102, the SMF+PGW-C obtains the tunnel information of switching the PDN connection of the terminal in the second network to the PDU session in the first network according to the first request message.

[0478] It should be noted that S1103a~S1105a or S1103b~S1105b is the process of the SMF+PGW-C and the UPF+PGW-U establishing a tunnel for the PDU session.

[0479] Optionally, the tunnel information corresponding to the PDU session can be allocated by the SMF+PGW-C or by UPF+PGW-U, which is not limited in the embodiments of the present application.

[0480] Among them, if the tunnel information is allocated by the SMF+PGW-C, S1103a~S1105a are executed; if the tunnel information is allocated by the UPF+PGW-U, S1103b~S1105b are executed.

[0481] (1) The SMF+PGW-C allocates tunnel information for the PDU session.

[0482] S1103a, the SMF+PGW-C allocates user plane tunnel information for the PDU session.

[0483] S1104a, the SMF+PGW-C sends an N4 session establishment / modification request to the UPF+PGW-U, where the N4 session establishment / modification request is used to request the establishment of a tunnel corresponding to the PDU session, and the N4 session establishment / modification request carries the tunnel information and uplink data transmission rules of the PDU session, where the uplink data transmission rules are used to instruct the user plane functional network element corresponding to the PDN connection how to forward the uplink data received through the user plane tunnel corresponding to the PDU session; accordingly, the UPF+PGW-U receives the N4 session establishment / modification request from the SMF+PGW-C.

[0484] S1105a, the UPF+PGW-U sends an N4 session establishment / modification response to the SMF+PGW-C according to the N4 session establishment / modification request received in S1104a; accordingly, the SMF+PGW-C receives the N4 session establishment / modification response from the UPF+PGW-U.

[0485] (2) The UPF+PGW-U allocates tunnel information for the PDU session.

[0486] S1103b, the SMF+PGW-C sends an N4 session establishment / modification request to the UPF+PGW-U, where the N4 session establishment / modification request is used to request the establishment of a tunnel corresponding to the PDU session, and the N4 session establishment / modification request carries the tunnel information and uplink data transmission rules of the PDU session, where the uplink data transmission rules are used to instruct the user plane functional network element corresponding to the PDN connection how to forward the uplink data received through the user plane tunnel corresponding to the PDU session; accordingly, the UPF+PGW-U receives the N4 session establishment / modification request from the SMF-PGW-C.

[0487] S1104b, the UPF+PGW-U allocates tunnel information for the PDU session according to the N4 session establishment / modification request received in S1103b.

[0488] S1105b, the UPF+PGW-U sends an N4 session establishment / modification response to the SMF+PGW-C, and the N4 session establishment / modification response carries the tunnel information corresponding to the PDU session; accordingly, the SMF+PGW-C receives the N4 session establishment / modification request from the UPF+PGW-U.

[0489] After S1105b, the SMF+PGW-C saves the tunnel information corresponding to the PDU session.

[0490] Optionally, the SMF+PGW-C or the UPF+PGW-U can use the tunnel corresponding to a bearer in the second network as the tunnel corresponding to the functional PDU session in the first network, for example, use the tunnel of the default bearer as the tunnel corresponding to the PDU session. In this case, the uplink tunnel information allocated by the SMF+PGW-C to the PDU session is the tunnel information of the user plane tunnel corresponding to the default bearer on PGW-U+UPF; or the SMF+PGW-C can allocate new uplink tunnel information for the PDU session in the first network.

[0491] The present application provides several possible implementation methods:

[0492] Option 1: Execute only S1103a, and do not execute S1104a and S1105a.

[0493] Optional method 2: Execute S1103a to S1105a.

[0494] Option three: Execute S1103b~S1105b.

[0495] Option 4: Do not execute S1103a-1105a, and do not execute S1103b-1105b.

[0496] Specifically, the SMF+PGW-C determines the uplink and downlink data transmission rules according to the TFT (Traffic Filter Template) information of each bearer connected to the PDN, wherein the TFT includes the packet filter of the data stream supported by the bearer.

[0497] S1106: The source access network in the second network (such as Fig.11 The eNB in ​​the first network sends a switching request to the MME in the second network, and the switching request carries information of the target access network (such as the gNB in ​​the first network); accordingly, the MME receives the switching request from the source access network.

[0498] It should be understood that the access network described in the embodiments of the present application may be, for example, a base station.

[0499] S1107, the MME selects an AMF according to the information of the target access network, and sends a switching request to the AMF, where the switching request carries the EPS bearer context; accordingly, the AMF receives the switching request from the MME.

[0500] S1108, the AMF sends a session establishment request to the SMF+PGW-C corresponding to each PDN connection in the EPS bearer context, and the session establishment request carries the default bearer identifier corresponding to the PDN connection; accordingly, the SMF+PGW-C receives the session establishment request from the AMF.

[0501] In a possible implementation, the default bearer identifier carried in the session establishment request in S1108 can be used to instruct the SMF+PGW-C to prepare for the terminal to switch from the second network to the first network.

[0502] In another possible implementation, the session establishment request in S1108 may also carry first indication information, where the first indication information is used to instruct the SMF+PGW-C to prepare for the terminal to switch from the second network to the first network, where the first indication information may be, for example, at least one bit.

[0503] If method 1 is adopted: S1104a to S1105a are executed after S1108.

[0504] If method 4 is adopted, method 2 or method 3 is executed after S1108.

[0505] S1109, the SMF+PGW-C queries the session context according to the default bearer identifier, and generates an N2 session request according to the information in the session context. The N2 session request includes the identifier of the PDU session, the S-NSSAI corresponding to the PDU session, the session AMBR, and the QoS flow information in the PDU session.

[0506] Optionally, the N2 session request message also includes uplink tunnel information of UPF+PGW-U of the PDU session.

[0507] S1110, the SMF+PGW-C sends the N2 session request to the AMF; accordingly, the AMF receives the N2 session request from the SMF+PGW-C.

[0508] Optionally, after S1110, the AMF may notify the target access network to prepare for switching the terminal from the second network to the first network, for example, notifying the target access network to allocate radio resources and allocate access network tunnel information (for example, a downlink tunnel of the access network) for the session to be switched.

[0509] S1111, after the terminal accesses the target access network, the AMF sends a session update request to the SMF+PGW-C, and the session update request carries the received downlink tunnel information corresponding to the access network; accordingly, the SMF+PGW-C receives the session update request from the AMF.

[0510] Optionally, the session update request carries third indication information, and the third indication information is used to notify the SMF+PGW-C to switch the path to the first network, for example, PGW-U+UPF switches to sending downlink data through the access network in the first network.

[0511] S1112, the SMF+PGW-C sends an N4 session update request to the UPF+PGW-U, and the N4 session update request carries the downlink forwarding rule and the downlink tunnel information of the target access network. The downlink data transmission rule is used to indicate that the downlink data packet received by the user plane functional network element corresponding to the PDN connection is sent through the user plane tunnel corresponding to the PDU session; accordingly, the UPF+PGW-U receives the N4 session update request from the SMF+PGW-C.

[0512] S1113, the SMF+PGW-C sends an N4 session update response to the AMF.

[0513] In a possible implementation, the N4 session update request in S1112 may not carry the downlink data transmission rule, and the downlink data transmission rule may be carried in the N4 session establishment / modification request in S1104a or S1103b. The N4 session establishment / modification request in S1104a or S1103b also carries first rule indication information, and the first rule indication information is used to indicate that the downlink data transmission rule is not enabled.

[0514] Correspondingly, the N4 session update request in S1112 may carry second rule indication information, where the second rule indication information is used to indicate the activation of the downlink data packet transmission rule; the UPF+PGW-U activates the downlink data packet transmission rule according to the second rule indication information.

[0515] Fig.12 A schematic flow chart of a method 1200 for switching provided in an embodiment of the present application is shown. The method 1200 can be applied to Figure 2 In the system architecture in the roaming scenario shown, or, the method 1200 can also be applied to other similar architectures.

[0516] It should be understood that the first network may include a 5G network, and the second network may include a 4G network, which is not limited in this embodiment of the present application.

[0517] It should also be understood that since there is no control plane tunnel corresponding to the PDU session in the first network, the tunnel corresponding to the PDU session described in the embodiments of the present application refers to the user plane tunnel corresponding to the PDU session, and the tunnel information corresponding to the PDU session refers to the user plane tunnel information corresponding to the PDU session.

[0518] S1201~S1202 are similar to S1101~S1102.

[0519] S1203a~S1205a are similar to S1103a~S1105a.

[0520] S1203b~S1205b are similar to S1103b~S1105b.

[0521] The present application provides several possible implementation methods:

[0522] Option 1: Execute only S1203a, and do not execute S1204a and S1205a.

[0523] Optional method 2: Execute S1203a to S1205a.

[0524] Optional method three: Execute S1203b~S1205b.

[0525] Option 4: Do not execute S1203a-1205a, and do not execute S1203b-1205b.

[0526] S1206: The source access network in the second network (such as Fig.12 The eNB in ​​the first network sends a switching request to the MME in the second network, and the switching request carries information of the target access network (such as the gNB in ​​the first network); accordingly, the MME receives the switching request from the source access network.

[0527] It should be understood that the access network described in the embodiments of the present application may be, for example, a base station.

[0528] S1207, similar to S1107.

[0529] S1208, the AMF selects v-SMF and sends a session establishment request to the v-SMF. The session establishment request carries the default bearer identifier corresponding to the PDN connection and the identifier of the SMF+PGW-C corresponding to the PDN connection in the EPS bearer context. Accordingly, the v-SMF receives the session establishment request from the AMF.

[0530] Optionally, the session establishment request carries fourth indication information, where the fourth indication information is used to indicate preparation for switching the terminal from the second network to the first network.

[0531] Optionally, the fourth indication information may be the default bearer identifier.

[0532] Optionally, the fourth session management request carries the default bearer identifier and the fourth indication information, and the fourth indication information is used to indicate preparation for switching the terminal from the second network to the first network, wherein the fourth indication information may be at least one bit.

[0533] S1209, the v-SMF sends a session modification request to the SMF+PGW-C according to the identifier of the SMF+PGW-C, and the session modification request carries the default bearer identifier corresponding to the PDN connection; accordingly, the SMF+PGW-C receives the session modification request from the v-SMF.

[0534] In a possible implementation, the default bearer identifier carried in the session modification request in S1209 can be used to instruct the SMF+PGW-C to prepare for the terminal to switch from the second network to the first network.

[0535] In another possible implementation, the session modification request in S1209 may also carry a first indication message, where the first indication information is used to instruct the SMF+PGW-C to prepare for the terminal to switch from the second network to the first network, where the first indication information may be, for example, at least one bit.

[0536] If method 1 is adopted: S1204a to S1205a are executed after S1209.

[0537] If method 4 is adopted, method 2 or method 3 is executed after S1209.

[0538] S1210, the SMF+PGW-C queries the session context according to the default bearer identifier, and generates an N2 session request according to the information in the session context. The N2 session request includes the identifier of the PDU session, the S-NSSAI corresponding to the PDU session, the session AMBR, and the QoS flow information in the PDU session.

[0539] S1211, the SMF+PGW-C sends the N2 session request received in S1210 and the uplink tunnel information on the UPF+PGW-U of the PDU session to the v-SMF; accordingly, the v-SMF receives the N2 session request received in S1210 and the uplink tunnel information on the UPF+PGW-U of the PDU session from the SMF+PGW-C.

[0540] S1212, the v-SMF allocates v-UPF and sends an N4 session request to the v-UPF. The N4 session request carries the uplink tunnel information of UPF+PGW-U of the PDU session. Accordingly, the v-UPF receives the N4 session request from the v-SMF.

[0541] Optionally, after S1212, a corresponding uplink tunnel from v-UPF to UPF+PGW-U will be created on the v-UPF for the PDU session, and the N3 uplink tunnel information on the v-UPF will be allocated.

[0542] S1213, the v-SMF adds the N3 uplink tunnel information on the v-UPF to the N2 session request received in S1211.

[0543] S1214, the v-SMF sends a session establishment response to the AMF, and sends an N2 session request to the AMF; accordingly, the AMF receives the session establishment response and the N2 session request from the v-SMF.

[0544] Optionally, after S1214, the AMF may notify the target base station to prepare for switching of the terminal from the second network to the first network, for example, notifying the target base station to allocate wireless resources and allocate base station tunnel information (for example, the downlink tunnel of the base station) for the session to be switched.

[0545] S1215, when the UE accesses the target access network (such as Fig.12 After the target access network sends a handover notification message to the AMF, the AMF receives the handover notification message from the target access network.

[0546] S1216, the AMF sends a session update request to the v-SMF, and the session update request carries the received downlink tunnel information of the access network; accordingly, the v-SMF receives the session update request from the AMF.

[0547] Optionally, the message carries switching completion indication information, and the v-SMF can determine whether the switching is completed based on the indication.

[0548] S1217, the v-SMF sends an N4 session update request to the v-UPF, and the N4 session update request carries the downlink tunnel information of the target access network; accordingly, the v-UPF receives the N4 session update request from the v-SMF.

[0549] S1218, the v-SMF sends a session update request to the SMF+PGW-C, and the session update request carries the downlink tunnel information of the v-UPF; accordingly, the CMF+PGW-C receives the session update request from the v-SMF.

[0550] Optionally, the session update request also carries switching completion indication information, where the switching completion indication information is used to indicate that the switching is completed.

[0551] S1219, the SMF+PGW-C sends an N4 session update request to the UFP+PGW-U. The third session management request carries downlink data transmission rules and downlink tunnel information of the v-UPF. The downlink data transmission rules are used to indicate that the downlink data packet received by the user plane function network element corresponding to the PDN connection is sent through the user plane tunnel corresponding to the PDU session.

[0552] S1220, the SMF+PGW-C sends a session update response to the v-SMF; accordingly, the v-SMF receives the session update response from the SMF+PGW-C.

[0553] S1221, the v-SMF sends a session update response to the AMF; accordingly, the AMF receives the session update response from the v-SMF.

[0554] In one possible implementation, the third session management request in S1219 may not carry the downlink data transmission rule, and the downlink data transmission rule may be carried in the first session management request in S1204a or S1203b, and the first session management request also carries first indication information, and the first indication information is used to indicate that the downlink data transmission rule is not enabled.

[0555] Correspondingly, the third session management request in S1219 may carry second indication information, where the second indication information is used to indicate the activation of the downlink data packet transmission rule; the UPF+PGW-U activates the downlink data packet transmission rule according to the second indication information.

[0556] Optionally, SMF+PGW-C can determine that the switching is completed based on the switching completion indication information in S1218, thereby notifying PGW-U+UPF to enable downlink forwarding, or sending the downlink data transmission rules to PGW-U+UPF to enable downlink forwarding.

[0557] Combined with the above Figures 3 to 12 The switching method provided in the embodiment of the present application is introduced. Figures 13 to 18 The present invention introduces a device for switching provided in an embodiment of the present application.

[0558] Fig.13 A schematic block diagram of a switching device 1300 provided in an embodiment of the present application is shown. The switching device 1300 includes a determining unit 1310 and an acquiring unit 1320 .

[0559] A determining unit 1310 is configured to determine at least one bearer that needs to be established when a protocol data unit PDU session of a terminal in a first network is switched to a packet data network PDN connection in a second network;

[0560] The acquiring unit 1320 is configured to acquire tunnel information of the PDN connection, where the tunnel information of the PDN connection includes user plane tunnel information corresponding to each bearer in the at least one bearer.

[0561] Optionally, the acquisition unit 1320 is specifically used to: allocate corresponding user plane tunnel information to each bearer in the at least one bearer; or, request the user plane functional network element corresponding to the PDU session to allocate user plane tunnel information corresponding to each bearer, and obtain the user plane tunnel information corresponding to each bearer from the user plane functional network element corresponding to the PDU session.

[0562] Optionally, the tunnel information of the PDN connection also includes control plane tunnel information corresponding to the PDN, and the acquisition unit 1320 is further used to: acquire the control plane tunnel information corresponding to the PDN connection.

[0563] Optionally, the device 1300 also includes: a first sending unit, used to send a first session management request to the user plane functional network element corresponding to the PDU session, the first session management request is used to request to establish or modify the user plane tunnel corresponding to each bearer in the at least one bearer, the first session management request carries an uplink data transmission rule, and the uplink data transmission rule is used to instruct the user plane functional network element corresponding to the PDU session how to forward the uplink data received through the user plane tunnel corresponding to the PDN connection.

[0564] Optionally, the acquisition unit 1320 is further used to: acquire a bearer identifier corresponding to each bearer in the at least one bearer.

[0565] Optionally, the acquisition unit 1320 is specifically used to: send a bearer identifier request to the mobility management network element through the second control plane function network element, and the bearer identifier request is used to request the allocation of a bearer identifier for each bearer in the at least one bearer; wherein the second control plane function network element is the visited control plane network element corresponding to the PDU session, and the device is the home control plane network element corresponding to the PDU session; and receive the bearer identifier corresponding to each bearer in the at least one bearer from the mobility management network element through the second control plane function network element.

[0566] Optionally, the device 1300 also includes: a second sending unit, used to send the tunnel information of the PDN connection and the bearer identifier corresponding to each bearer in the at least one bearer to the second control plane function network element.

[0567] Optionally, the device 1300 also includes: a third sending unit, used to send tunnel information of the PDN connection to the second control plane functional network element; wherein the second control plane functional network element is the visited control plane network element corresponding to the PDU session, and the device is the home control plane network element corresponding to the PDU session; the acquisition unit 1320 is also used to receive the bearer identifier corresponding to each bearer in the at least one bearer from the second control plane functional network element.

[0568] Optionally, the acquisition unit 1320 is specifically used to: when it is determined that the PDU session of the terminal needs to be established in the first network or the PDU session in the first network needs to be modified, acquire the tunnel information of the PDN connection.

[0569] Optionally, the device 1300 also includes: a fourth sending unit, used to send the downlink data transmission rules corresponding to the PDN connection to the user plane functional network element corresponding to the PDU session, and the downlink data transmission rules are used to instruct the user plane functional network element corresponding to the PDU session to forward the received downlink data using the corresponding user plane tunnel.

[0570] It should be noted that in the embodiment of the present invention, the determining unit 1310 may be implemented by a processor, and the acquiring unit 1320 may be implemented by a transceiver. Fig.14 As shown, the switching device 1400 may include a processor 1410, a memory 1420, and a transceiver 1430. The memory 1420 may be used to store codes executed by the processor 1410, and the processor 1410 may be used to process data or programs.

[0571] In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in the processor 1410 or an instruction in the form of software. The steps of the method disclosed in conjunction with the embodiment of the present invention can be directly embodied as being executed by a hardware processor, or can be executed by a combination of hardware and software modules in the processor. The software module can be located in a mature storage medium in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 1420, and the processor 1410 reads the information in the memory 1420 and completes the steps of the above method in conjunction with its hardware. To avoid repetition, it will not be described in detail here.

[0572] Fig.13 The apparatus 1300 for switching or Fig.14 The device 1400 for switching shown can implement the various processes of the first control plane functional network element corresponding to the aforementioned method embodiment. Specifically, the device 1300 for switching or the device 1400 for switching can refer to the description above. To avoid repetition, it will not be repeated here.

[0573] Fig.15 A schematic block diagram of a switching device 1500 provided in an embodiment of the present application is shown. The switching device includes an acquiring unit 1510 and a sending unit 1520 .

[0574] An acquiring unit 1510 is configured to receive tunnel information of a packet data network PDN connection from a first control plane function network element, where the tunnel information of the PDN connection includes user plane tunnel information corresponding to each bearer in at least one bearer, the device is a visited control plane network element corresponding to the PDN connection, and the first control plane function network element is a home control plane network element corresponding to the PDN connection;

[0575] The sending unit 1520 is configured to send the tunnel information of the PDN connection to a mobility management network element.

[0576] Optionally, the tunnel information of the PDN connection also includes control plane tunnel information corresponding to the PDN connection.

[0577] Optionally, the sending unit 1520 is also used to: forward to the mobility management network element a bearer identifier request sent by the first control plane function to the mobility management network element, the bearer identifier request being used to request allocation of a bearer identifier for each bearer in the at least one bearer; and forward to the first control plane function network element a bearer identifier corresponding to each bearer in the at least one bearer sent by the mobility management network element to the first control plane function.

[0578] Optionally, the acquiring unit 1510 is further used to: receive a bearer identifier corresponding to each bearer in the at least one bearer from the first control plane function network element.

[0579] Optionally, the sending unit 1520 is also used to: send a bearer identification request to the mobility management network element according to the tunnel information of the PDN connection, and the bearer identification request is used to request the allocation of a bearer identification for each bearer in the at least one bearer; the acquisition unit 1510 is also used to receive the bearer identification corresponding to each bearer in the at least one bearer from the mobility management network element.

[0580] Optionally, the device also includes: a storage unit, which is used to store the bearer identifier corresponding to each bearer in the at least one bearer; the sending unit 1520 is also used to: send the bearer identifier corresponding to each bearer in the at least one bearer to the first control plane functional network element.

[0581] It should be noted that in the embodiment of the present invention, the acquisition unit 1510 and the sending unit 1520 can be implemented by a transceiver. Fig.16 As shown, the switching device 1600 may include a processor 1610, a memory 1620, and a transceiver 1630. The memory 1620 may be used to store codes executed by the processor 1610, and the processor 1610 may be used to process data or programs.

[0582] In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in the processor 1610 or an instruction in the form of software. The steps of the method disclosed in conjunction with the embodiment of the present invention can be directly embodied as being executed by a hardware processor, or can be executed by a combination of hardware and software modules in the processor. The software module can be located in a mature storage medium in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 1620, and the processor 1610 reads the information in the memory 1620 and completes the steps of the above method in conjunction with its hardware. To avoid repetition, it will not be described in detail here.

[0583] Fig.15 The device 1500 for switching or Fig.16 The device 1600 for switching shown can implement the various processes of the aforementioned method embodiment corresponding to the second control plane network. Specifically, the device 1500 for switching or the device 1600 for switching can refer to the description above. To avoid repetition, it will not be repeated here.

[0584] Fig.17 A schematic block diagram of a switching device 1700 provided in an embodiment of the present application is shown. The switching device 1700 includes a determining unit 1710 and an acquiring unit 1720 .

[0585] The determining unit 1710 is configured to determine that a packet data network PDN connection of the terminal in the second network needs to be switched to a protocol data unit PDU session in the first network;

[0586] The acquisition unit 1720 is used to acquire the user plane tunnel information corresponding to the PDU session.

[0587] Optionally, the acquisition unit 1720 is specifically used to: allocate user plane tunnel information corresponding to the PDU session to the PDU session; or request the user plane functional network element corresponding to the PDN connection to allocate user plane tunnel information corresponding to the PDU session, and obtain user plane tunnel information corresponding to the PDU session sent from the user plane functional network element corresponding to the PDN connection.

[0588] Optionally, the device 1700 also includes: a first sending unit, used to send a first session management request to the user plane functional network element corresponding to the PDN connection, the first session management request is used to request to establish or modify the user plane tunnel corresponding to the PDU session, the first session management request carries an uplink data transmission rule, and the uplink data transmission rule is used to instruct the user plane functional network element corresponding to the PDN connection how to forward the uplink data received through the user plane tunnel corresponding to the PDU session.

[0589] Optionally, the first sending unit is further used to: when it is determined that the uplink data transmission rule has changed, send an updated uplink data transmission rule to a user plane functional network element corresponding to the PDN connection.

[0590] Optionally, the acquiring unit 1720 is further used to: receive a second session management request, where the second session management request carries first indication information, where the first indication information is used to indicate preparation for switching the terminal from the second network to the first network.

[0591] Optionally, the device 1700 also includes: a second sending unit, used to send the downlink data transmission rules corresponding to the PDU session to the user plane functional network element corresponding to the PDN connection, and the downlink data transmission rules are used to indicate the sending of the downlink data packet received by the user plane functional network element corresponding to the PDN connection through the user plane tunnel corresponding to the PDU session.

[0592] It should be noted that in the embodiment of the present invention, the determining unit 1710 may be implemented by a processor, and the acquiring unit 1720 may be implemented by a transceiver. Fig.18 As shown, the communication device 1800 may include a processor 1810, a memory 1820, and a transceiver 1830. The memory 1820 may be used to store codes executed by the processor 1810, and the processor 1810 may be used to process data or programs.

[0593] In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in the processor 1810 or an instruction in the form of software. The steps of the method disclosed in conjunction with the embodiment of the present invention can be directly embodied as being executed by a hardware processor, or can be executed by a combination of hardware and software modules in the processor. The software module can be located in a mature storage medium in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 1820, and the processor 1810 reads the information in the memory 1820 and completes the steps of the above method in conjunction with its hardware. To avoid repetition, it will not be described in detail here.

[0594] Fig.17 The device 1700 for switching or Fig.18 The device 1800 for switching shown can implement the various processes of the first control plane functional network element corresponding to the aforementioned method embodiment. Specifically, the device 1700 for switching or the device 1800 for switching can refer to the description above. To avoid repetition, it will not be repeated here.

[0595] An embodiment of the present application also provides a computer-readable medium for storing a computer program, wherein the computer program includes instructions for executing the method corresponding to the first control plane function network element or the second control plane function network element in the above method embodiment.

[0596] An embodiment of the present application also provides a computer program product, which includes: computer program code. When the computer program code is executed by a communication unit, a processing unit or a transceiver, or a processor of a communication device (for example, a terminal device or a network device), the communication device executes the method corresponding to the first control plane function network element or the second control plane function network element in any of the above method embodiments.

[0597] An embodiment of the present application also provides a communication chip, in which instructions are stored. When the instructions are executed on a communication device, the communication chip executes the method corresponding to the first control plane function network element or the second control plane function network element in the above method embodiment.

[0598] The various embodiments in this application may be used independently or in combination, which is not limited here.

[0599] It should be understood that the first, second, etc. descriptions appearing in the embodiments of the present application are only used for illustration and distinction of the description objects, and there is no distinction in order. They do not indicate any special limitation on the number of devices in the embodiments of the present application, and cannot constitute any limitation on the embodiments of the present application.

[0600] It should also be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0601] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software 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.

[0602] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0603] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, 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.

[0604] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0605] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0606] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage media include: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM), random access memories (RAM), magnetic disks or optical disks.

[0607] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A communication method, characterized in that: include: When the first control plane functional network element establishes a protocol data unit PDU session of the terminal in the first network or modifies the PDU session, it obtains tunnel information of a packet data network PDN connection in the second network corresponding to the PDU session, wherein the PDN connection corresponds to at least one bearer, and the tunnel information of the PDN connection includes user plane tunnel information corresponding to each bearer in the at least one bearer.

2. The method according to claim 1, characterized in that The tunnel information of the PDN connection is stored in the bearer context corresponding to the PDN connection.

3. The method according to claim 1 or 2, characterized in that: The first control plane function network element obtains the tunnel information of the PDN connection, including: The first control plane function network element allocates corresponding user plane tunnel information to each bearer in the at least one bearer; or, The first control plane function network element requests the user plane function network element corresponding to the PDU session to allocate the user plane tunnel information corresponding to each bearer, and obtains the user plane tunnel information corresponding to each bearer from the user plane function network element corresponding to the PDU session.

4. The method according to any one of claims 1 to 3, characterized in that: The tunnel information of the PDN connection also includes control plane tunnel information corresponding to the PDN connection, and the first control plane function network element obtains the tunnel information of the PDN connection, further including: The first control plane function network element obtains control plane tunnel information corresponding to the PDN connection.

5. The method according to any one of claims 1 to 4, characterized in that The method further comprises: The first control plane function network element sends a first session management request to the user plane function network element corresponding to the PDU session, where the first session management request is used to request establishment or modification of a user plane tunnel corresponding to each bearer in the at least one bearer, and the first session management request carries an uplink data transmission rule, where the uplink data transmission rule is used to instruct the user plane function network element corresponding to the PDU session how to forward uplink data received through the user plane tunnel corresponding to the PDN connection.

6. The method according to any one of claims 1 to 5, characterized in that The method also includes: the first control plane function network element obtains a bearer identifier corresponding to each bearer in the at least one bearer.

7. The method according to claim 6, characterized in that The method further comprises: The first control plane function network element associates a bearer identifier corresponding to each bearer in the at least one bearer with the tunnel information of the PDN connection.

8. The method according to claim 6, characterized in that The acquiring a bearer identifier corresponding to each bearer in the at least one bearer includes: The first control plane function network element sends a bearer identifier request to the mobility management network element through the second control plane function network element, where the bearer identifier request is used to request allocation of a bearer identifier for each of the at least one bearer; The first control plane function network element receives a bearer identifier corresponding to each bearer in the at least one bearer from the mobility management network element through the second control plane function network element.

9. The method according to claim 8, characterized in that The second control plane function network element is a visited control plane network element corresponding to the PDU session, and the first control plane function network element is a home control plane network element corresponding to the PDU session.

10. The method according to claim 6, characterized in that The acquiring a bearer identifier corresponding to each bearer in the at least one bearer includes: The first control plane function network element sends a bearer identifier request to the mobility management network element, where the bearer identifier request is used to request allocation of a bearer identifier for each of the at least one bearer; The first control plane function network element receives a bearer identifier corresponding to each bearer in the at least one bearer from the mobility management network element.

11. The method according to claim 8 or 9, characterized in that: The method further comprises: The first control plane function network element sends the bearer context corresponding to the PDN connection to the second control plane function network element; wherein the bearer context corresponding to the PDN connection includes tunnel information of the PDN connection and a bearer identifier corresponding to each bearer in the at least one bearer.

12. The method according to any one of claims 1 to 11, characterized in that The method further comprises: The first control plane functional network element sends the downlink data transmission rule corresponding to the PDN connection to the user plane functional network element corresponding to the PDU session, and the downlink data transmission rule is used to instruct the user plane functional network element corresponding to the PDU session to forward the received downlink data using the corresponding user plane tunnel.

13. The method according to any one of claims 1 to 12, characterized in that Before acquiring tunnel information of a packet data network PDN connection in a second network corresponding to the PDU session, the method further includes: The first control plane function network element determines the at least one bearer corresponding to the PDN connection.

14. A communication method, characterized in that: include: The first control plane function network element determines that a packet data network PDN connection of the terminal in the second network needs to be switched to a protocol data unit PDU session in the first network; The first control plane function network element obtains user plane tunnel information corresponding to the PDU session, and The first control plane function network element sends a first session management request to the user plane function network element corresponding to the PDN connection, where the first session management request is used to request establishment or modification of a user plane tunnel corresponding to the PDU session, and the first session management request carries an uplink data transmission rule, where the uplink data transmission rule is used to instruct the user plane function network element corresponding to the PDN connection how to forward uplink data received through the user plane tunnel corresponding to the PDU session.

15. The method according to claim 14, characterized in that The first control plane function network element obtains user plane tunnel information corresponding to the PDU session, including: The first control plane function network element allocates user plane tunnel information corresponding to the PDU session to the PDU session; or The first control plane function network element requests the user plane function network element corresponding to the PDN connection to allocate the user plane tunnel information corresponding to the PDU session, and obtains the user plane tunnel information corresponding to the PDU session sent from the user plane function network element corresponding to the PDN connection.

16. The method according to claim 15, characterized in that The method further comprises: When the first control plane functional network element determines that the uplink data transmission rule has changed, the first control plane functional network element sends an updated uplink data transmission rule to a user plane functional network element corresponding to the PDN connection.

17. The method according to claim 14 or 16, characterized in that Before the first control plane function network element sends the first session management request to the user plane function network element corresponding to the PDN connection, the method further includes: The first control plane function network element receives a second session management request, where the second session management request carries first indication information, where the first indication information is used to indicate preparation for switching the terminal from the second network to the first network.

18. The method according to any one of claims 14 to 17, characterized in that The method further comprises: The first control plane functional network element sends the downlink data transmission rule corresponding to the PDU session to the user plane functional network element corresponding to the PDN connection, and the downlink data transmission rule is used to indicate that the downlink data packet received by the user plane functional network element corresponding to the PDN connection is sent through the user plane tunnel corresponding to the PDU session.

19. A communication device, characterized in that: include: A unit for acquiring tunnel information of a packet data network (PDN) connection in a second network corresponding to the PDU session when establishing a protocol data unit (PDU) session of a terminal in a first network or modifying a PDU session, wherein the PDN connection corresponds to at least one bearer, and the tunnel information of the PDN connection includes user plane tunnel information corresponding to each bearer in the at least one bearer.

20. The communication device according to claim 19, characterized in that The tunnel information of the PDN connection is stored in the bearer context corresponding to the PDN connection.

21. The communication device according to claim 19 or 20, characterized in that: The acquisition unit is specifically used for: Allocating corresponding user plane tunnel information to each bearer in the at least one bearer; or, Request the user plane function network element corresponding to the PDU session to allocate the user plane tunnel information corresponding to each bearer, and obtain the user plane tunnel information corresponding to each bearer from the user plane function network element corresponding to the PDU session.

22. The communication device according to any one of claims 19 to 21, characterized in that: The tunnel information of the PDN connection also includes control plane tunnel information corresponding to the PDN connection, and the acquisition unit is further used to: acquire the control plane tunnel information corresponding to the PDN connection.

23. The communication device according to any one of claims 19 to 22, characterized in that: Also includes: A first sending unit for sending a first session management request to a user plane function network element corresponding to the PDU session, wherein the first session management request is used to request establishment or modification of a user plane tunnel corresponding to each bearer in the at least one bearer, and the first session management request carries an uplink data transmission rule, and the uplink data transmission rule is used to instruct the user plane function network element corresponding to the PDU session how to forward uplink data received through the user plane tunnel corresponding to the PDN connection.

24. The communication device according to any one of claims 19 to 23, characterized in that: The acquisition unit also Used to obtain a bearer identifier corresponding to each bearer in the at least one bearer.

25. The communication device according to claim 24, characterized in that The communication device is further configured to associate a bearer identifier corresponding to each bearer in the at least one bearer with tunnel information of the PDN connection.

26. The communication device according to claim 24, characterized in that The acquisition unit is specifically used for: Sending a bearer identifier request to the mobility management network element through the second control plane function network element, where the bearer identifier request is used to request allocation of a bearer identifier for each of the at least one bearer; as well as The bearer identifier corresponding to each bearer in the at least one bearer is received from the mobility management network element through the second control plane function network element.

27. The communication device according to claim 26, characterized in that The second control plane function network element is a visited control plane network element corresponding to the PDU session, and the communication device is a home control plane network element corresponding to the PDU session.

28. The communication device according to claim 24, characterized in that The acquisition unit is specifically used for: Sending a bearer identifier request to a mobility management network element, where the bearer identifier request is used to request allocation of a bearer identifier for each of the at least one bearer; and A bearer identifier corresponding to each bearer in the at least one bearer is received from the mobility management network element.

29. The communication device according to claim 26 or 27, characterized in that: Also includes: A unit for sending the bearer context corresponding to the PDN connection to the second control plane function network element; wherein the bearer context corresponding to the PDN connection includes tunnel information of the PDN connection and a bearer identifier corresponding to each bearer in the at least one bearer.

30. The communication device according to any one of claims 19 to 29, characterized in that: Also includes: Used to send a downlink data transmission rule unit corresponding to the PDN connection to the user plane function network element corresponding to the PDU session, wherein the downlink data transmission rule is used to instruct the user plane function network element corresponding to the PDU session to forward the received downlink data using the corresponding user plane tunnel.

31. The communication device according to any one of claims 19 to 30, characterized in that: Also includes: A unit for determining the at least one bearer corresponding to the PDN connection before acquiring tunnel information of the packet data network PDN connection in the second network corresponding to the PDU session.

32. A communication device, characterized in that: include: A unit for determining that a packet data network PDN connection of the terminal in the second network needs to be switched to a protocol data unit PDU session in the first network; an acquisition unit for acquiring user plane tunnel information corresponding to the PDU session, and A first sending unit for sending a first session management request to a user plane function network element corresponding to the PDN connection, wherein the first session management request is used to request establishment or modification of a user plane tunnel corresponding to the PDU session, and the first session management request carries an uplink data transmission rule, and the uplink data transmission rule is used to instruct the user plane function network element corresponding to the PDN connection how to forward uplink data received through the user plane tunnel corresponding to the PDU session.

33. The communication device according to claim 32, characterized in that: The acquisition unit is specifically used for: Allocating user plane tunnel information corresponding to the PDU session to the PDU session; or Request the user plane function network element corresponding to the PDN connection to allocate the user plane tunnel information corresponding to the PDU session, and obtain the user plane tunnel information corresponding to the PDU session sent from the user plane function network element corresponding to the PDN connection.

34. The communication device according to claim 32, characterized in that The first sending unit also Used to send an updated uplink data transmission rule to a user plane function network element corresponding to the PDN connection when it is determined that the uplink data transmission rule has changed.

35. The communication device according to claim 32 or 34, characterized in that: The acquisition unit is further used to receive a second session management request before sending a first session management request to the user plane function network element corresponding to the PDN connection, wherein the second session management request carries first indication information, and the first indication information is used to indicate preparation for switching the terminal from the second network to the first network.

36. The communication device according to any one of claims 32 to 35, characterized in that: Also includes: A unit for sending a downlink data transmission rule corresponding to the PDU session to a user plane function network element corresponding to the PDN connection, wherein the downlink data transmission rule is used to indicate that a downlink data packet received by the user plane function network element corresponding to the PDN connection is sent through a user plane tunnel corresponding to the PDU session.

37. A control plane function network element, characterized in that: including a processor and a memory; The memory is used to store computer-executable instructions. When the control plane function network element is running, the processor executes the computer-executable instructions stored in the memory to enable the control plane function network element to perform the method according to any one of claims 1 to 18.

38. A computer-readable storage medium, characterized in that: The method comprises instructions which, when executed on a computer, cause the computer to execute the method according to any one of claims 1 to 18.

39. A computer program product comprising instructions, which, when executed on a computer, causes the computer to perform the method according to any one of claims 1 to 18.

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