Communication method and device

Abstract

The present application relates to a communication method and a device. The method comprises: a terminal sending a first request by means of a first access network device, wherein the first request is configured for requesting to establish a first connection of a first session with a user plane network element by means of the first access network device, the first request carries a first indicating parameter, the first indicating parameter is configured for indicating that the terminal requests a first function to be performed for the first session, and the first function is a function that enables the terminal to maintain, by means of a plurality of access network devices, a plurality of connections with the user plane network element for the same session when cross-access network device handover is required.

Description

Communication methods and devices Technical Field

[0001] This application relates to the field of communications, and more specifically, to a communication method and apparatus. Background Technology

[0002] The handover process in related technologies involves a release-then-switch procedure, meaning there's a period of inactivity in terminal data transmission during which no uplink or downlink data can be transmitted. This is particularly unacceptable for latency-sensitive services. Therefore, how to avoid this period of inability to transmit uplink and downlink data during the handover process and achieve seamless switching between them becomes a problem that needs to be solved.

[0003] Summary of the Invention

[0004] This application provides a communication method and device.

[0005] This application provides a communication method, including:

[0006] The terminal sends a first request through a first access network device, wherein the first request is used to request the establishment of a first connection of a first session with a user plane network element through the first access network device, the first request carries a first indication parameter, the first indication parameter is used to instruct the terminal to request the execution of a first function for the first session, the first function is the function of the terminal maintaining multiple connections of the same session with the user plane network element through multiple access network devices when it needs to switch across access network devices.

[0007] This application provides a communication method, including:

[0008] The first core network device receives a first request from the terminal through the first access network device. The first request is used to request the establishment of a first connection of a first session with the user plane network element through the first access network device. The first request carries a first indication parameter, which is used to instruct the terminal to request the execution of a first function for the first session. The first function is the function of the terminal maintaining multiple connections of the same session with the user plane network element through multiple access network devices when it needs to switch across access network devices.

[0009] This application provides a communication method, including:

[0010] The second core network device receives a second request from the terminal through the second access network device, wherein the second request is used to request the establishment of a second connection of the first session with the user plane network element through the second access network device.

[0011] This application provides a communication method, including:

[0012] The terminal establishes a first connection and a second connection of the first session with a user plane network element, wherein the first connection is established between the terminal and the user plane network element through a first access network device, and the second connection is established between the terminal and the user plane network element through the second access network device when the terminal needs to switch from the first access network device to the second access network device;

[0013] When the terminal transmits data of the first session with the user plane network element through the second connection, the first connection is released.

[0014] This application provides a communication method, including:

[0015] The user plane network element establishes a first connection and a second connection of the first session with the terminal, wherein the first connection is established between the terminal and the user plane network element through a first access network device, and the second connection is established between the terminal and the user plane network element through the second access network device when the terminal needs to switch from the first access network device to the second access network device;

[0016] When the user plane network element transmits the data of the first session to the terminal through the second connection, the first connection is released.

[0017] This application provides a terminal, including:

[0018] The first communication unit is configured to send a first request through a first access network device, wherein the first request is configured to request the establishment of a first connection of a first session with a user plane network element through the first access network device, the first request carries a first indication parameter, the first indication parameter is configured to instruct the terminal to request the execution of a first function for the first session, the first function being the function of the terminal maintaining multiple connections of the same session with the user plane network element through multiple access network devices when it needs to switch across access network devices.

[0019] This application provides a first core network device, including:

[0020] The second communication unit is configured to receive a first request from a terminal via a first access network device. The first request is configured to request the establishment of a first connection of a first session with a user plane network element via the first access network device. The first request carries a first indication parameter, which is configured to instruct the terminal to request the execution of a first function for the first session. The first function is the function of maintaining multiple connections of the same session between the terminal and the user plane network element through multiple access network devices when the terminal needs to switch across access network devices.

[0021] This application provides a second core network device, including:

[0022] The third communication unit is configured to receive a second request from a terminal via the second access network device, wherein the second request is configured to request the establishment of a second connection of a first session with a user plane network element via the second access network device.

[0023] This application provides a terminal, including:

[0024] The first communication unit is used to establish a first connection and a second connection of the first session with a user plane network element, wherein the first connection is established between the terminal and the user plane network element through a first access network device, and the second connection is established between the terminal and the user plane network element through the second access network device when the terminal needs to switch from the first access network device to the second access network device; when transmitting data of the first session with the user plane network element through the second connection, the first connection is released.

[0025] This application provides a user plane network element, including:

[0026] The fourth communication unit is used to establish a first connection and a second connection of the first session with the terminal, wherein the first connection is established between the terminal and the user plane network element through the first access network device, and the second connection is established between the terminal and the user plane network element through the second access network device when the terminal needs to switch from the first access network device to the second access network device; when transmitting data of the first session with the terminal through the second connection, the first connection is released.

[0027] This application provides a terminal, including a transceiver, a processor, and a memory. The memory stores a computer program, the transceiver communicates with other devices, and the processor calls and runs the computer program stored in the memory to enable the terminal to perform the methods described above.

[0028] This application provides a first core network device, including a transceiver, a processor, and a memory. The memory stores a computer program, the transceiver communicates with other devices, and the processor calls and runs the computer program stored in the memory to cause the first core network device to perform the aforementioned method.

[0029] This application provides a second core network device, including a transceiver, a processor, and a memory. The memory stores a computer program, the transceiver communicates with other devices, and the processor calls and runs the computer program stored in the memory to enable the second core network device to perform the methods described above.

[0030] This application provides a user plane network element, including a transceiver, a processor, and a memory. The memory stores a computer program, the transceiver communicates with other devices, and the processor calls and runs the computer program stored in the memory to enable the user plane network element to perform the methods described above.

[0031] This application provides a chip for implementing the above method.

[0032] Specifically, the chip includes a processor for retrieving and running a computer program from memory, causing a device equipped with the chip to perform the methods described above.

[0033] This application provides a computer-readable storage medium for storing a computer program, which, when run by a device, causes the device to perform the above-described method.

[0034] This application provides a computer program product, including computer program instructions that cause a computer to perform the above-described method.

[0035] By adopting the above scheme, when the terminal sends a first request to establish a first connection of a first session with a user plane network element through a first access network device, the first request carries a first indication parameter to instruct the terminal to request the subsequent execution of a first function for the currently established first session. The first function is the function of maintaining multiple connections of the same session with the user plane network element through multiple access network devices during cross-access network device handover. In this way, by enhancing the session establishment process, a foundation is provided for the subsequent establishment of a second connection of the first session, enabling the terminal to maintain multiple connections of the same session for a period of time during cross-access network device handover. This ensures that the terminal will not experience any situation where it is unable to transmit uplink and downlink data, thereby realizing a handover mechanism of establishing first and then disconnecting, that is, achieving seamless handover of uplink and downlink data. Attached Figure Description

[0036] Figure 1 is a schematic diagram of an application scenario according to an embodiment of this application.

[0037] Figure 2 is a schematic flowchart of a communication method according to an embodiment of this application.

[0038] Figure 3 is a schematic flowchart of a communication method according to another embodiment of this application.

[0039] Figure 4 is a schematic flowchart of a communication method according to another embodiment of this application.

[0040] Figure 5 is a schematic flowchart of a communication method according to another embodiment of this application.

[0041] Figure 6 is a schematic flowchart of a communication method according to another embodiment of the present application.

[0042] Figures 7 and 8 are schematic diagrams of two scenarios in which a terminal performs cross-base station handover according to an embodiment of this application.

[0043] Figures 9 and 10 are schematic flowcharts of two processes for establishing a first connection and a second connection according to an embodiment of this application.

[0044] Figures 11 and 12 are two schematic flowcharts illustrating the data switching process performed on the user plane according to an embodiment of this application.

[0045] Figure 13 is a schematic block diagram of a terminal according to an embodiment of the present application.

[0046] Figure 14 is a schematic block diagram of a first core network device according to an embodiment of the present application.

[0047] Figure 15 is a schematic block diagram of a second core network device according to an embodiment of the present application.

[0048] Figure 16 is a schematic block diagram of a user plane network element according to an embodiment of the present application.

[0049] Figure 17 is a schematic block diagram of a communication device according to an embodiment of this application.

[0050] Figure 18 is a schematic block diagram of a chip according to an embodiment of this application.

[0051] Figure 19 is a schematic block diagram of a communication system according to an embodiment of the present application. Detailed Implementation

[0052] The technical solutions of this application embodiment can be applied to various communication systems, such as: LTE (Long Term Evolution), LTE-A (Long Term Evolution-Advanced), NR (New Radio), evolution of NR, WLAN (Wireless Local Area Network), WiFi (Wireless Fidelity), or other communication systems.

[0053] This application describes various embodiments in conjunction with network devices and terminals. The terminal can be mobile or fixed, and may also be referred to as a mobile station, user unit, etc. The terminal can be a station in a WLAN, or a smart terminal, wireless modem, laptop, tablet, etc. In this application embodiment, the terminal can be a VR (Virtual Reality) terminal / AR (Augmented Reality) terminal, industrial control terminal, autonomous driving terminal, telemedicine terminal, smart grid terminal, transportation safety terminal, smart city terminal, or smart home wireless terminal, etc. By way of example and not limitation, in this application embodiment, the terminal can also be a wearable device.

[0054] In this embodiment, the network device can be a device for communicating with a terminal. The network device can be an access point in a WLAN, an evolved base station in LTE, a relay station, a vehicle-mounted device, a wearable device, a network device in an NR network (gNB, the next generation Node B), a network device in a future PLMN network, or a network device in a non-terrestrial network, etc. By way of example and not limitation, in this embodiment, the network device can have mobility characteristics; for example, the network device can be a mobile device.

[0055] To facilitate understanding of the technical solutions of the embodiments of this application, the relevant technologies of the embodiments of this application are described below. The following relevant technologies are optional solutions and can be combined with the technical solutions of the embodiments of this application in any way, and they all fall within the protection scope of the embodiments of this application.

[0056] Figure 1 exemplarily illustrates a communication system 100. The communication system includes network devices 110 and terminals 120. In one possible implementation, the communication system 100 may include multiple network devices 110, and the coverage area of ​​each network device 110 may include one or more terminals 120; this embodiment does not limit this. In another possible implementation, the communication system 100 may also include other network entities such as mobility management entities and access and mobility management functions; this embodiment does not limit this. The network devices may further include access network devices and core network devices. That is, the communication system may also include multiple core networks for communicating with the access network devices. The access network devices may be base stations of LTE, LTE-A, or NR systems. Taking the communication system shown in Figure 1 as an example, the communication devices may include network devices and terminals with communication functions. The communication devices may also include other devices in the communication system, such as network controllers, mobility management entities, and other network entities; this embodiment does not limit this.

[0057] Figure 2 is a schematic flowchart of a communication method according to an embodiment of this application. The method includes at least a portion of the following.

[0058] S210. The terminal sends a first request through a first access network device, wherein the first request is used to request the establishment of a first connection of a first session with a user plane network element through the first access network device, the first request carries a first indication parameter, the first indication parameter is used to instruct the terminal to request the execution of a first function for the first session, the first function is the function of the terminal maintaining multiple connections of the same session with the user plane network element through multiple access network devices when it needs to switch across access network devices.

[0059] Figure 3 is a schematic flowchart of a communication method according to an embodiment of this application. The method includes at least a portion of the following.

[0060] S310. The first core network device receives a first request from the terminal through the first access network device. The first request is used to request the establishment of a first connection of a first session with the user plane network element through the first access network device. The first request carries a first indication parameter, which is used to instruct the terminal to request the execution of a first function for the first session. The first function is the function of the terminal maintaining multiple connections of the same session with the user plane network element through multiple access network devices when it needs to switch across access network devices.

[0061] Figure 4 is a schematic flowchart of a communication method according to an embodiment of this application. The method includes at least a portion of the following.

[0062] S410, the second core network device receives a second request from the terminal through the second access network device, wherein the second request is used to request the establishment of a second connection of the first session with the user plane network element through the second access network device.

[0063] Figure 5 is a schematic flowchart of a communication method according to an embodiment of this application. The method includes at least a portion of the following.

[0064] S510. The terminal establishes a first connection and a second connection of the first session with the user plane network element, wherein the first connection is established between the terminal and the user plane network element through the first access network device, and the second connection is established between the terminal and the user plane network element through the second access network device when the terminal needs to switch from the first access network device to the second access network device.

[0065] S520: When the terminal transmits data of the first session with the user plane network element through the second connection, the first connection is released.

[0066] Figure 6 is a schematic flowchart of a communication method according to an embodiment of this application. The method includes at least a portion of the following.

[0067] S610. The user plane network element and the terminal establish a first connection of the first session and a second connection of the first session, wherein the first connection is established between the terminal and the user plane network element through the first access network device, and the second connection is established between the terminal and the user plane network element through the second access network device when the terminal needs to switch from the first access network device to the second access network device.

[0068] S620: If the user plane network element transmits the data of the first session with the terminal through the second connection, release the first connection.

[0069] In some possible implementations, before the terminal sends the first request through the first access network device, the method further includes: the terminal receiving a first RSD (Route Selection Descriptor), wherein the first RSD includes the first indication parameter.

[0070] Receiving the first RSD by the terminal may include: the terminal receiving a URSP (User Route Selection Policy) from a third core network device, wherein the URSP includes the first RSD.

[0071] As long as the terminal receives the URSP from the third core network device before the terminal sends the first request, it is within the protection scope of this embodiment. Here, we do not limit the specific process or procedure by which the terminal receives the URSP from the third core network device.

[0072] Among them, the third core network device can be any control plane network element on the core network side, such as the third core network device can be a PCF (Policy Control Function).

[0073] For example, the first RSD is a component of the URSP. For instance, the URSP may include a List of RSDs, which may contain one or more RSDs. At least one of these RSDs may include a first indicator parameter. Additionally, it should be noted that the URSP may also include various other components specified by relevant protocols. For example, the URSP may also include: Traffic descriptors (the traffic descriptor component that defines the URSP rules), IP descriptors (including destination IP triples), Non-IP descriptors (destination information descriptors used for non-IP traffic), and so on. This does not limit or exhaustively list the possible contents of the URSP.

[0074] Taking any RSD that includes the first indication parameter as an example, besides the first indication parameter, the first RSD may also include other content specified by relevant protocols. For example, the first RSD may also include at least one of the following: SSC (Session and Service Continuity) mode selection, network slice selection, DNN (Data Network Name) selection, PDU session type selection, etc. This document does not limit or exhaustively list all the possible contents that any RSD may contain. It should be noted that there may be more than one RSD containing the first indication parameter in the URSP routing descriptor list. The subsequent session establishment processing and related descriptions for each RSD containing the first indication parameter are the same as those for the session establishment corresponding to the first RSD, and will not be elaborated upon in this embodiment.

[0075] The first indication parameter can be a newly added parameter. The first indication parameter can be a parameter containing specified components, which are not limited in this embodiment. The first indication parameter can be carried by the terminal when sending a session establishment request to request the execution of a first function for that session, thereby enabling negotiation with the network side (or negotiation on whether to execute the first function). Here, "session" can refer to any session in general, or it can refer to any session corresponding to the first RSD. This first indication parameter may also be called a Make Before Break (MMB) indication, etc., and not all possible names for the first indication parameter are limited here.

[0076] For example, the terminal receives a first RSD, extracts a first indication parameter from the first RSD, and stores it locally. When the terminal subsequently initiates a session establishment request corresponding to the first RSD, it carries the first indication parameter. This first indication parameter instructs the terminal to request the execution of a first function for the session corresponding to the first RSD. In other words, the first indication parameter enables the network-side receiving end (such as the first core network device) to determine that the terminal requests the execution of a first function for the session corresponding to the first RSD. Correspondingly, the network-side receiving end (such as the first core network device) can determine, based on the terminal's subscription information, whether to allow or support the terminal to execute the first function (or whether to allow or support the terminal to execute the first function for the session corresponding to the first RSD), and send a session establishment response to the terminal. This establishment response can be used to indicate whether the terminal is allowed or supported to execute the first function.

[0077] The first function is the function of the terminal maintaining multiple connections of the same session with user plane network elements through multiple access network devices when it needs to switch across access network devices.

[0078] This first function can be referred to as the MMB function. This first function can also be described as the terminal maintaining multiple connections within the same session with user plane network elements through multiple access network devices when a handover across access network devices is required; or, this first function can also be described as the terminal maintaining multiple connections within the same session with user plane network elements through multiple access network devices; or, this first function can also be described as the terminal maintaining multiple connections within the same session with user plane network elements through multiple access network devices, etc. Not all possible alternative descriptions of this first function are limited or exhaustively listed here.

[0079] Here, "same session" can refer to any session in general, while the specific session it refers to depends on which session's establishment request requests the execution of the first function. For example, in a subsequent embodiment, if the terminal requests the execution of the first function for the first session in the first request to establish the first session, then "same session" refers to the first session. Correspondingly, multiple connections within the same session can refer to multiple connections within the first session, where different connections are established with user plane network elements through different access network devices. For instance, in a subsequent embodiment, this might include the first connection and the second connection of the first session. As another example, in some other embodiments, if the terminal requests the execution of the first function for the second session in the request to establish the second session, then "same session" refers to the second session. Correspondingly, multiple connections within the same session can refer to multiple connections within the second session, where different connections are established with user plane network elements through different access network devices. For instance, the multiple connections of the second session might include the first connection and the second connection of the second session, and could also include other connections of the second session, etc. This is not a limitation or an exhaustive list.

[0080] The phrase "terminal needs to switch across access network devices" can refer to the stage where the terminal needs to perform a switch across access network devices.

[0081] The cross-access network device handover includes at least one of the following: handover between different access network devices under the same core network, and handover between different access network devices under different core networks.

[0082] The plurality of access network devices may include the source access network device and the target access network device in any instance where the terminal needs to switch across access network devices.

[0083] Optionally, the RAT (Radio Access Technology) corresponding to the source access network device and the target access network device may be the same or different.

[0084] The RAT corresponding to either the source access network device or the target access network device can be at least one of the following: E-UTRA (Evolved Universal Terrestrial Radio Access), NR terrestrial access, NR satellite access, etc. For example, the RAT corresponding to the source access network device and the RAT corresponding to the target access network device can be the same, both being NR terrestrial access; for example, the RAT corresponding to the source access network device can be E-UTRA, and the RAT corresponding to the target access network device can be NR satellite access. Here, we do not limit or exhaustively list the RATs corresponding to the source access network device and the target access network device respectively.

[0085] Optionally, the source access network device and the target access network device may be located in the same or different types of networks.

[0086] For example, the network type of either the source access network device or the target access network device can be one of the following: TN (Terrestrial Network) or NTN (Non-Terrestrial Network). For instance, the network type of the source access network device and the network type of the target access network device can be the same, both being TN. For example, the network type of the source access network device can be TN, and the network type of the target access network device can be NTN.

[0087] For example, the network type of either the source access network device or the target access network device can be one of the following: PLMN (Public Land Mobile Network) or NPN (Non-public network). For instance, the source access network device's network type can be PLMN, and the target access network device's network type can be NPN. Alternatively, the source and target access network devices can both be of the same type, PLMN.

[0088] Here, we do not limit or exhaustively list the types of networks where the source access network device and the target access network device are located.

[0089] Furthermore, the network numbers of the source access network device and the target access network device can be the same or different. For example, the network type of the source access network device and the network type of the target access network device can both be PLMN, the network number of the source access network device can be PLMN1, and the network number of the target access network device can be PLMN2.

[0090] Optionally, the system types corresponding to the source access network device and the target access network device (or the system types corresponding to the networks where the source access network device and the target access network device are located) can be the same or different.

[0091] The system type corresponding to either the source access network device or the target access network device (or the system type corresponding to the network where either the source access network device or the target access network device is located) can be one of the following: 6GS (6th Generation System), 5GS (5th Generation System), or EPS (Evolved Packet System). For example, the system type corresponding to the source access network device can be 5GS, and the system type corresponding to the target access network device can be 6GS. Here, we do not limit or exhaustively list the system types corresponding to the source and target access network devices respectively.

[0092] In the case of switching between different access network devices under the same core network (or the same network or the same system), the source access network device and the target access network device belong to the same core network.

[0093] In the case of switching between different access network devices under different core networks (or different networks or different systems) across access network devices, the source access network device and the target access network device belong to different core networks.

[0094] In other words, if the terminal enables or performs the first function, then when the terminal needs to switch across access network devices, in addition to maintaining one connection between the source access network device and the user plane network element to maintain the session, the terminal can also establish another connection between the target access network device and the user plane network element to maintain the same session. When the terminal maintains two connections in the same session, the terminal may transmit session data through only one connection in the same session, or the terminal may transmit session data through both connections at the same time.

[0095] Referring to Figure 7, an exemplary illustration is provided. Assuming that the same core network (or the same system or the same network) includes base station-1 and base station-2, during the handover preparation phase, the terminal maintains a connection with the core network through base station-1 (i.e., the source access network device). During the handover phase (referred to as handover in progress), the terminal establishes another connection with the core network through base station-2 (i.e., the target access network device), and the terminal maintains two connections with the core network through base station-1 and base station-2 respectively. After the handover, the connection with the core network through base station-1 can be released, and data transmission can be performed through the connection with the core network through base station-2.

[0096] Referring to Figure 8, another exemplary illustration is provided. Assuming that base station-1 belongs to core network-1 and base station-2 belongs to core network-2, during the handover preparation phase, the terminal maintains a connection established between base station-1 (i.e., the source access network device) and core network-1. During the handover phase (referred to as handover in progress), the terminal establishes another connection between base station-2 (i.e., the target access network device) and core network-2, and the terminal maintains two connections between base station-1 and base station-2 with the two core networks respectively. After the handover, the connection between base station-1 and core network-1 can be released, and data transmission can be performed through the connection between base station-2 and core network-2.

[0097] The first function (MMB function) is explained with reference to the examples in Figure 7 or Figure 8: When the terminal moves from the coverage area of ​​base station-1 to the coverage area of ​​base station-2, that is, when the terminal switches from one system to another system or from one base station to another, it will be in a brief dual-connection state during the handover process. That is, the terminal maintains a connection with two base stations at the same time. This function is called the first function (or MMB function).

[0098] Furthermore, taking the handover between different access network devices in different core networks, different networks, or different systems as an example, before the terminal moves out of the coverage edge of the access network device (source access network device) of the first network or the first system, if the terminal uses or executes the first function, the terminal can initiate the establishment of a second leg corresponding to the connection currently in use in the first network in the second network (the access network device of the second network or the second system, i.e., the target access network device) based on the multi-connection capability, and maintain the data transmission state of the first leg. The first leg and the second leg are anchored on the same user plane network element and share the same session address (such as IP address, MAC address, Non-IP address, etc.); when the terminal completes the establishment of the second leg and can transmit data through the second leg, it releases the first leg and returns to the single-connection state.

[0099] In this context, any "leg" refers to a connection established by the terminal with a user plane network element through an access network device. For example, the first leg refers to a connection established by the terminal through one access network device (with a user plane network element), and the second leg refers to another connection established by the terminal through another access network device (with a user plane network element). The first leg and the second leg (i.e., the two connections) can belong to the same session, that is, they correspond to the same session identifier and / or the same session address (such as an IP address, MAC address, or Non-IP address); or, the first leg and the second leg (i.e., the two connections) can belong to different sessions, that is, they correspond to different session identifiers and / or different session addresses (such as IP addresses, MAC addresses, or Non-IP addresses).

[0100] The session involved in this embodiment may refer to a PDU (Protocol Data Unit) session.

[0101] Multi-connectivity capability, also known as DualSteer capability, refers to the ability of a terminal to register and establish multiple connections with multiple access network devices and / or multiple core networks.

[0102] Terminals supporting this DualSteer capability can be called dual-connection terminals, dual-connection devices, multi-connection devices, multi-connection UEs, multi-connection terminals, etc. Terminals can be single-SIM or multi-SIM terminals; a single-SIM terminal refers to a terminal with a single USIM (Universal Subscriber Identity Module) card, while a multi-SIM terminal refers to a terminal with multiple USIM cards.

[0103] Registration can refer to NAS registration.

[0104] Among the multiple connections, different connections correspond to different access network devices and / or different core networks; any one of the multiple connections can be a PDU (Protocol Data Unit) session, a PDN (Packet Data Network Connection), etc.

[0105] In some possible implementations, the terminal sending the first request through the first access network device may include: the terminal sending the first request to the first core network device through the first access network device. Correspondingly, the first core network device receives the first request from the terminal through the first access network device.

[0106] The first core network device can be a control plane network element in the core network of the first network or the first system. For example, the first core network device can be an SMF (Session Management Function) in the core network of the first network.

[0107] The first access network device can be the device on the access network side corresponding to the terminal in the first network or the first system.

[0108] The message type of the first request can be a session establishment request, or a PDU session establishment request, etc.

[0109] The first session can refer to any session established by the terminal with the user plane network element through the first access network device. Preferably, the first session is the session corresponding to the first RSD.

[0110] The processing before the terminal sends the first request carrying the first indication parameter may further include: if the terminal needs to perform a first function on the data of the first session, determining that the first indication parameter is carried in the first request.

[0111] The first indication parameter is used to instruct the terminal to request the execution of a first function in the first session. The description of the first function is the same as in the previous embodiments and will not be repeated.

[0112] This embodiment requests the execution of a first function for the first session by including a first indication parameter in the first request. Specifically, when the terminal needs to switch from the first access network device to another access network device (such as the second access network device), it performs the function of maintaining the two connections of the currently requested first session between the first access network device and the user plane network element through the first and second access network devices. The two connections of the first session may include a first connection and a second connection of the first session.

[0113] It should be understood that this embodiment mainly describes the subsequent related processing using the first session as an example. In actual processing, the solution provided by this application can also be used for the second session or more other sessions. For example, if the terminal requests or instructs to perform the first function on the second session by carrying the first indication parameter in the request to establish the second session initiated by the third access network device, it means that when the terminal needs to switch from the third access network device to other access network devices (such as the fourth access network device), it performs the function of maintaining two connections (such as the first connection of the second session and the second connection of the second session) between the third access network device and the user plane network element through the fourth access network device. This is not limited or exhaustive.

[0114] In this embodiment and the related descriptions below, the first access network device is the source access network device in the aforementioned embodiments, and the second access network device is the target access network device in the aforementioned embodiments. This will not be repeated below. At least one of the following may be the same or different: the RAT corresponding to the first access network device and the second access network device, the type of network they reside in, the system type they correspond to, etc. The descriptions regarding the RAT corresponding to the first access network device and the second access network device, the type of network they reside in, and the system type they correspond to are the same as those regarding the source access network device and the target access network device in the aforementioned embodiments, and therefore will not be repeated.

[0115] In one example, the terminal may determine whether to perform the first function on the data of the first session based on local configuration. The content and specific configuration method of the local configuration are not limited in this embodiment.

[0116] In one example, the terminal may determine whether to perform a first function on the data of the first session based on the URSP. For instance, the terminal may determine that the first session needs to perform a first function on the data of the first session if it determines that the first session is the session corresponding to the first RSD included in the URSP.

[0117] In addition to carrying the first indication parameter, the first request may also carry the identifier of the first session. The method of generating the identifier of the first session is not limited in this embodiment.

[0118] It should be noted that, in addition to carrying the first instruction parameter and the identifier of the first session, the first request may also carry other content required by the relevant protocol for the session establishment request, which will not be limited or exhaustively listed here.

[0119] In some possible implementations, after the first core network device receives the first request from the terminal through the first access network device, the method further includes: the first core network device sending a first reply to the terminal, wherein the first reply indicates the completion of establishing the first connection, and the first reply carries a second indication parameter, which indicates whether the terminal is supported or allowed to perform the first function. After the terminal sends the first request through the first access network device, the method further includes: the terminal receiving the first reply, wherein the first reply indicates the completion of establishing the first connection, and the first reply carries a second indication parameter, which indicates whether the terminal is supported or allowed to perform the first function. Specifically, the terminal receiving the first reply can be: the terminal receiving a first reply from the first core network device.

[0120] Here, the message type of the first reply can be a session establishment reply or a PDU session establishment reply.

[0121] Whether the terminal is supported or allowed to perform the first function may refer to whether the terminal's first session is supported or allowed to perform the first function.

[0122] Before the first core network device sends the first reply to the terminal, the method further includes: the first core network device determining the second indication parameter based on the terminal's subscription information.

[0123] The method by which the first core network device obtains the terminal's subscription information may include: the first core network device obtaining the terminal's subscription information from a fourth core network device. The fourth core network device may be a core network element with storage capabilities in the first network or the first system; for example, the fourth core network device may be a UDM (Unified Data Management).

[0124] The terminal's subscription information may include MMB subscription parameters, which may include content (or subscription data) related to whether the terminal supports or allows the execution of the first function (or MMB function). It should be noted that the terminal's subscription information may also include other content stipulated in relevant protocols; however, this embodiment avoids limitation or exhaustive enumeration.

[0125] The first core network device determines the second indication parameter based on the terminal's subscription information, which may include: if the MMB subscription parameter in the terminal's subscription information includes whether the terminal supports or is allowed to perform the first function, the first core network device generates a second indication parameter to indicate that the terminal supports or is allowed to perform the first function (or supports or allows the first session of the terminal to perform the first function); or, if the MMB subscription parameter in the terminal's subscription information includes whether the terminal does not support or is not allowed to perform the first function, the first core network device generates a second indication parameter to indicate that the terminal does not support or is not allowed to perform the first function (or does not support or is not allowed to perform the first function in the first session of the terminal).

[0126] Optionally, in addition to carrying the second indication parameter, the first response may also carry at least one of the following: a token parameter associated with the first session, or allowed network information, wherein the allowed network information is used by the terminal to determine the networks permitted for establishing the second connection of the first session.

[0127] The token parameter associated with the first session can be generated by the first core network device. This embodiment does not limit the specific generation method of the token parameter associated with the first session. As long as the token parameter associated with the first session is different from the identifier of the first session, it is within the protection scope of this embodiment.

[0128] In one scenario, if the second indication parameter in the first response is used to indicate support for or permission for the terminal to perform the first function, the first response may carry a token parameter associated with the first session. In another scenario, regardless of whether the second indication parameter in the first response is used to indicate support for or permission for the terminal to perform the first function, the first response may carry a token parameter associated with the first session.

[0129] The permitted network information may enable the terminal to determine which network or system to use to establish the second connection of the first session, or may enable the terminal to determine which network or system it is permitted to use to establish the second connection of the first session. The permitted network information may include at least one of the following: information about the system corresponding to the network that the terminal is permitted to use to establish the second connection of the first session, the network that the terminal is permitted to use to establish the second connection of the first session, the RAT corresponding to the network that the terminal is permitted to use to establish the second connection of the first session, etc.

[0130] The information related to the systems corresponding to the networks that the terminal is allowed to use to establish the second connection of the first session may include at least one of the following: the system name of each network in the one or more networks that the terminal is allowed to use to establish the second connection of the first session, and the system type of each network in the one or more networks that the terminal is allowed to use to establish the second connection of the first session. For example, the system type of each network in the one or more networks that the terminal is allowed to use to establish the second connection of the first session may include at least one of the following: 6GS, 5GS, EPS, etc.

[0131] The networks permitted for establishing a second connection for the terminal to establish a first session may include the type of each of one or more networks permitted for establishing a second connection for the terminal to establish a first session, and / or the number of each network permitted for establishing a second connection for the terminal to establish a first session. The type of any network may include one of the following: TN, NTN; and / or, the type of any network may include one of the following: PLMN, NPN.

[0132] For example, the allowed network information may include the type of network that the terminal is allowed to use for establishing the second connection of the first session. This network type can be at least one of PLMN and NPN. As another example, the allowed network information may include the type of network and network ID that the terminal is allowed to use for establishing the second connection of the first session. The network type can be at least one of PLMN and NPN; taking the example that the type of network allowed for establishing the second connection of the first session is PLMN, the network ID can be a PLMN ID.

[0133] The RAT corresponding to the network that the terminal is allowed to use to establish the second connection of the first session may include one or more RATs allowed in each of the one or more networks that the terminal is allowed to use to establish the second connection of the first session. The one or more RATs may include at least one of the following: E-UTRA, NR terrestrial access, and NR satellite access.

[0134] It should be noted that this is merely an illustrative example, and permitted network information may include other content, which is not limited or exhaustively listed here. Furthermore, the content that may be included in the first response may include, but is not limited to, the content shown in the examples above, and may also include other content stipulated in relevant agreements, which are also not limited or exhaustively listed here.

[0135] Before sending the first reply, the first core network device may further include configuring first relevant parameters of the first session to the user plane network element. These first relevant parameters can be used by the user plane network element to establish a first connection with the terminal through the first access network device. The user plane network element can be selected by the first core network device, and the specific method by which the first core network device selects the user plane network element is not limited in this embodiment. The user plane network element can refer to a UPF (User Plane Function). The first relevant parameters of the first session may include session-related parameters specified in relevant protocols, and are not limited here.

[0136] In addition, the processing of the first core network device may also include at least one of the following: the first core network device stores the association relationship between the identifier of the first session and the identifier of the user plane network element; the first core network device stores the association relationship between the token parameter associated with the first session and the identifier of the user plane network element; the first core network device stores the association relationship between the token parameter associated with the first session, the identifier of the first session and the identifier of the user plane network element; the first core network device sends the association relationship between the identifier of the first session and the identifier of the user plane network element to the fourth core network device; the first core network device sends the association relationship between the token parameter associated with the first session and the identifier of the user plane network element to the fourth core network device; the first core network device sends the association relationship between the token parameter associated with the first session, the identifier of the first session and the identifier of the user plane network element to the fourth core network device. Accordingly, the processing of the fourth core network device may also include at least one of the following: the fourth core network device receives and saves the association between the identifier of the first session from the first core network device and the identifier of the user plane network element; the fourth core network device receives and saves the association between the token parameter associated with the first session from the first core network device and the identifier of the user plane network element; the fourth core network device receives and saves the association between the token parameter associated with the first session, the identifier of the first session and the identifier of the user plane network element from the first core network device.

[0137] The identifier of the user plane network element may include the number of the user plane network element and / or the entity identifier (Instance ID) of the user plane network element, etc., which are not limited or exhaustively listed here.

[0138] In some possible implementations, after the terminal receives the first reply, the method further includes: if the terminal needs to switch from the first access network device to the second access network device, the terminal sends a second request through the second access network device, wherein the second request is used to request the establishment of a second connection of the first session with the user plane network element through the second access network device.

[0139] In one embodiment, the first access network device and the second access network device are different access network devices under the same core network, the same network, or the same system.

[0140] In this embodiment, the terminal sends a second request through the second access network device, specifically: the terminal sends a second request to the first core network device through the second access network device.

[0141] After the first core network device sends a first reply to the terminal, the process further includes: the first core network device receiving a second request from the terminal through a second access network device, wherein the second request is used to request the establishment of a second connection of the first session with the user plane network element through the second access network device.

[0142] Optionally, the terminal may be a second access network device that determines the first network based on the currently detected signal strength. The specific determination method is not limited here.

[0143] The second request can also be a session establishment request or a PDU session establishment request. The second request carries at least one of the following: the identifier of the first session, and the token parameter associated with the first session.

[0144] After receiving the second request from the terminal through the second access network device, the first core network device further includes: determining the user plane network element based on the identifier of the first session and / or the token parameter associated with the first session. This user plane network element is the user plane network element corresponding to the first session.

[0145] Optionally, the second request carries the identifier of the first session.

[0146] In this scenario, the first core network device can determine the user plane network element corresponding to the first session based on the association between the identifier of the first session stored locally and the identifier of the user plane network element.

[0147] Optionally, the second request carries a token parameter associated with the first session.

[0148] In this scenario, the first core network device can determine the user plane network element corresponding to the first session based on the association between the token parameters associated with the first session stored locally and the identifier of the user plane network element.

[0149] Optionally, the second request carries the identifier of the first session and the token parameter associated with the first session.

[0150] In this scenario, the first core network device can determine the user plane network element corresponding to the first session based on the association between the identifier of the first session and the identifier of the user plane network element stored locally. Alternatively, the first core network device can determine the user plane network element corresponding to the first session based on the association between the token parameters associated with the first session and the identifier of the user plane network element stored locally. Or, the first core network device can determine the user plane network element corresponding to the first session based on the association between the token parameters associated with the first session of the first core network device, the identifier of the first session, and the identifier of the user plane network element stored locally.

[0151] After the first core network device determines the user plane network element and before sending the second reply, the process may further include: the first core network device configuring second relevant parameters of the first session to the user plane network element. These second relevant parameters of the first session can be used by the user plane network element to establish a second connection with the terminal through the second access network device. This second connection can also be used to transmit data from the first session; this second connection can be referred to as the second connection corresponding to the first session. It should be understood that both the first connection and the second connection can be used to transmit data from the first session, but at the same time, the first connection and the second connection may transmit data from the first session simultaneously, or either the first connection or the second connection may transmit data from the first session simultaneously.

[0152] The second relevant parameters of the first session may have some identical and / or different content from the first relevant parameters of the first session. For example, the second relevant parameters of the first session and the first relevant parameters of the first session may both include the same address of the first session, which may include at least one of the following: IP address, MAC (Media Access Control) address, Non-IP address, etc. For example, the first relevant parameters of the first session may include parameters related to the first access network device, and the second relevant parameters of the first session may include parameters related to the second access network device. This part belongs to the difference between the first and second relevant parameters of the first session; wherein, the parameters related to the first access network device may include at least one of the following: Tunnel ID (tunnel identifier) ​​related to the first access network device, TE ID (Traffic Endpoint ID) related to the first access network device, and the parameters related to the second access network device may include at least one of the following: Tunnel ID (tunnel identifier) ​​related to the second access network device, TE ID related to the second access network device, etc. It should be noted that the first and second relevant parameters of the first session may include various types of session-related parameters specified by relevant protocols, which are not limited or exhaustively listed here.

[0153] On the first core network device side, after determining the user plane network element, the method further includes: the first core network device sending a second response to the terminal, wherein the second response is used to indicate the completion of establishing the second connection. Correspondingly, after the terminal sends a second request through the second access network device, the method further includes: the terminal receiving a second response, wherein the second response is used to indicate the completion of establishing the second connection. Specifically, the terminal receiving the second response means: the terminal receiving a second response from the first core network device.

[0154] The second reply message type can be a session establishment reply or a PDU session establishment reply.

[0155] Optionally, the second response carries a handover indication parameter. This handover indication parameter can be used by the terminal during handover. Handover can refer to, for example, a handover of user plane data transmission. This handover indication parameter can be alternatively called a handover flag, handover identifier, handover indicator, etc.; not all possible names for this handover indication parameter are limited or exhaustively listed here.

[0156] It should be understood that, in another possible scenario, the second response may also be used to indicate that the establishment of the second connection has failed. Accordingly, after receiving the indication that the establishment of the second connection has failed, the terminal may not perform subsequent handover processing, or the terminal may initiate a new second request to request the establishment of the second connection again. Here, we will not limit or exhaust all the processing that the terminal may perform.

[0157] Referring to Figure 9, the process of establishing a first connection and a second connection for a terminal under the same core network or the same network is illustrated by the following example:

[0158] Step 901: The UE (i.e., the terminal) initiates a PDU session establishment request (i.e., the first request). In this example, the UE can be a dual-connectivity UE or a multi-connectivity UE. Specifically, the UE sends a PDU session establishment request to the core network control plane element (the first core network device, such as SMF) through base station-1 (the first access network device), carrying parameters such as the PDU session identifier (i.e., the identifier of the first session) and MBB indication.

[0159] Here, the UE can decide whether to perform MBB on the data of the PDU session (first session) based on the URSP, and then carry the MBB indication in the PDU session establishment request. Alternatively, the UE can decide whether to perform MBB (function) on the data of the PDU session (first session) based on the local configuration.

[0160] Step 902: The core network control plane element (SMF) interacts with the UDM to obtain subscription information (UE's subscription information). Optionally, the subscription information may include "MBB subscription parameters". The core network control plane element (SMF) determines whether to allow the terminal user or the terminal user's PDU session to perform MBB functions based on this.

[0161] Step 903: The core network control plane element (SMF) configures session parameters (i.e., the first relevant parameters of the first session) to the core network user plane element (UPF).

[0162] Step 904: The core network control plane element (SMF) sends a PDU session establishment reply message (i.e., the first reply) to the UE, which carries an indication parameter (second indication parameter) indicating whether MBB function is supported or allowed. Optionally, it may also carry a Token parameter (the token parameter associated with the first session) for use when initiating the second PDU session establishment.

[0163] Step 905: If the PDU session establishment reply message received by the UE in step 904 carries an indication parameter for indicating support or permission of MBB functionality, the UE initiates a second PDU session establishment request (i.e., the second request) when base station handover is required. Specifically, the UE sends the second PDU session establishment request to the core network control plane element (SMF) through base station-2 (the second access network device), carrying the same PDU session identifier (i.e., the identifier of the first session) and (optionally) a Token parameter.

[0164] Step 906: The core network control plane element (SMF) selects the same core network user plane element (UPF) for this connection establishment based on the PDU session identifier and / or Token parameter.

[0165] Step 907: The core network control plane element (SMF) configures session parameters (i.e., the second related parameters of the first session) to the core network user plane element (UPF). The session parameters configured in this step may include the same PDU session address (such as IP address, MAC address, or Non-IP address) as those configured in step 903; additionally, the session parameters configured in this step may also include content different from that configured in step 903, such as at least one of the following: Tunnel ID, TE ID, etc. The explanations regarding the content of the two session parameters are the same as in the aforementioned embodiments, and therefore will not be repeated.

[0166] Step 908: The core network control plane element (the first core network device, such as SMF) sends a PDU session establishment reply message (i.e., the second reply) to the UE. The PDU session establishment reply message carries the establishment result and (optionally) a handover flag. The handover flag is used during user plane data transmission handover.

[0167] It should be noted that some steps in the above examples may be optional in actual processing. For example, step 906 may be optional; if the core network control plane element can determine the core network user plane element to which the UE is connected using other methods, step 906 may not need to be executed. For example, step 907 may be optional; if the first relevant parameter and the second relevant parameter of the first session are the same, step 907 may not need to be executed. For example, step 908 may be optional; for example, the core network control plane element may not send a PDU session establishment reply message to the UE, in which case the UE may assume that the second connection was successfully established (or that another connection of the first session was successfully established). It should be noted that these are only some possible exemplary illustrations and are not intended to limit or exhaustively describe the embodiments of this application.

[0168] In one embodiment, the first access network device and the second access network device are different access network devices under different core networks, different networks, or different systems.

[0169] In this embodiment, the terminal sends a second request through the second access network device, specifically by sending a second request to the second core network device through the second access network device. The processing by the second core network device includes receiving the second request from the terminal through the second access network device.

[0170] Optionally, the terminal can be a second access network device determined based on the currently detected signal strength. The specific determination method is not limited here. This second network is different from the first network.

[0171] Optionally, the terminal can determine a second access network device under a second network, which is different from the first network, based on the currently searched signal strength and the allowed network information carried in the first response. For example, if the terminal currently searches for signals with high signal strength from access network devices under multiple networks, it selects a second network from these multiple networks that matches the allowed network information carried in the first response, and designates the access network device under this second network as the second access network device. Selecting a second network from these multiple networks that matches the allowed network information carried in the first response may include: selecting the network with the strongest signal from the access network devices that have not undergone matching processing, determining whether the network with the strongest signal matches the allowed network information carried in the first response, and if they match, designating the network with the strongest signal as the second network. Alternatively, it may include: if they do not match, continuing to select the network with the strongest signal from the access network devices that have not undergone matching processing, and so on, without further explanation.

[0172] The second core network device can be a control plane network element in the core network of the second network or the second system. For example, the second core network device can be an SMF in the core network of the second network.

[0173] The second access network device can be an access network-side device in a second network or a second system.

[0174] The message type of the second request can be the same as that of the first request, such as both being session establishment requests or PDU session establishment requests, etc.

[0175] The second request carries at least one of the following: the identifier of the first session, and the token parameter associated with the first session.

[0176] After receiving the second request from the terminal through the second access network device, the second core network device further includes: determining the user plane network element based on the identifier of the first session and / or the token parameter associated with the first session. This user plane network element is the user plane network element corresponding to the first session. It should also be noted that in this embodiment, the user plane network element can be a user plane network element co-located under different core networks, different networks, or different systems.

[0177] Optionally, the second request carries the identifier of the first session.

[0178] In this scenario, the second core network device determines the user plane network element based on the identifier of the first session. This process may include: the second core network device sending the identifier of the first session to the first core network device, and receiving the identifier of the user plane network element corresponding to the first session from the first core network device. The first core network device's processing may include: receiving the identifier of the first session from the second core network device; if it has a locally stored association relationship between the identifier of the first session and the identifier of the user plane network element, determining the user plane network element corresponding to the first session based on this association relationship, and sending the identifier of the user plane network element corresponding to the first session to the second core network device; if it does not have a locally stored association relationship between the identifier of the first session and the identifier of the user plane network element, sending the identifier of the first session to the fourth core network device, receiving the identifier of the user plane network element from the fourth core network device, and sending the identifier of the user plane network element corresponding to the first session to the second core network device.

[0179] Alternatively, the second core network device may determine the user plane network element based on the identifier of the first session, which may include: the second core network device sending the identifier of the first session to the fourth core network device, and receiving the identifier of the user plane network element corresponding to the first session from the fourth core network device. The processing of the fourth core network device may include: receiving the identifier of the first session from the second core network device, determining the user plane network element corresponding to the first session based on the association between the identifier of the first session and the identifier of the user plane network element, and sending the identifier of the user plane network element corresponding to the first session to the second core network device.

[0180] Optionally, the second request carries a token parameter associated with the first session.

[0181] In this scenario, the second core network device determines the user plane network element based on the token parameters associated with the first session. This process may include: the second core network device sending the token parameters associated with the first session to the first core network device, and receiving the identifier of the user plane network element corresponding to the first session from the first core network device. The first core network device's processing may include: receiving the token parameters associated with the first session from the second core network device; if it has a locally stored association relationship between the token parameters associated with the first session and the identifier of the user plane network element, determining the user plane network element corresponding to the first session based on this association relationship, and sending the identifier of the user plane network element corresponding to the first session to the second core network device; if it does not have a locally stored association relationship between the token parameters associated with the first session and the identifier of the user plane network element, sending the token parameters associated with the first session to the fourth core network device, receiving the identifier of the user plane network element from the fourth core network device, and sending the identifier of the user plane network element corresponding to the first session to the second core network device.

[0182] Alternatively, the second core network device may determine the user plane network element based on the token parameters associated with the first session. This may include: the second core network device sending the token parameters associated with the first session to the fourth core network device, and receiving the identifier of the user plane network element corresponding to the first session from the fourth core network device. The processing of the fourth core network device may include: receiving the token parameters associated with the first session from the second core network device, determining the user plane network element corresponding to the first session based on the association between the token parameters associated with the first session and the identifier of the user plane network element, and sending the identifier of the user plane network element corresponding to the first session to the second core network device.

[0183] Optionally, the second request carries the identifier of the first session and the token parameter associated with the first session.

[0184] In one scenario, the second core network device can determine the user plane network element based on the identifier of the first session. The specific processing method for the second core network device to determine the user plane network element based on the identifier of the first session is the same as in the previous example and will not be repeated here.

[0185] In one scenario, the second core network device can determine the user plane network element based on the token parameters associated with the first session. The specific processing method for the second core network device to determine the user plane network element based on the token parameters associated with the first session is the same as in the previous example and will not be repeated here.

[0186] In one scenario, the second core network device can determine the user plane network element based on the token parameters associated with the first session and the identifier of the first session.

[0187] For example, the second core network device can determine the user plane network element based on the token parameters associated with the first session and the identifier of the first session. This can include: the second core network device sending the token parameters associated with the first session and the identifier of the first session to the first core network device, and receiving the identifier of the user plane network element corresponding to the first session from the first core network device. The processing of the first core network device may include: receiving a token parameter associated with a first session and an identifier of the first session from the second core network device; if the association relationship between the token parameter associated with the first session, the identifier of the first session, and the identifier of the user plane network element is stored locally, determining the user plane network element corresponding to the first session based on the association relationship between the token parameter associated with the first session, the identifier of the first session, and the identifier of the user plane network element, and sending the identifier of the user plane network element corresponding to the first session to the second core network device; if the association relationship between the token parameter associated with the first session, the identifier of the first session, and the identifier of the user plane network element is not stored locally, sending the token parameter associated with the first session and the identifier of the first session to the fourth core network device, receiving the identifier of the user plane network element from the fourth core network device, and sending the identifier of the user plane network element corresponding to the first session to the second core network device.

[0188] Alternatively, the second core network device may determine the user plane network element based on the token parameters associated with the first session and the identifier of the first session. This may include: the second core network device sending the token parameters associated with the first session and the identifier of the first session to the fourth core network device, and receiving the identifier of the user plane network element corresponding to the first session from the fourth core network device. The processing of the fourth core network device may include: receiving the token parameters associated with the first session and the identifier of the first session from the second core network device, determining the user plane network element corresponding to the first session based on the association relationship between the token parameters associated with the first session, the identifier of the first session, and the identifier of the user plane network element, and sending the identifier of the user plane network element corresponding to the first session to the second core network device.

[0189] After the second core network device determines the user plane network element and before sending the second reply, the process may further include: the second core network device configuring second relevant parameters of the first session to the user plane network element. The description of these second relevant parameters of the first session is similar to that in the previous embodiments and will not be repeated here.

[0190] On the second core network device side, after determining the user plane network element, the process further includes: the second core network device sending a second response to the terminal, wherein the second response is used to indicate the completion of establishing the second connection. Correspondingly, after the terminal sends a second request through the second access network device, the process further includes: the terminal receiving a second response, wherein the second response is used to indicate the completion of establishing the second connection. Specifically, the terminal receiving the second response means: the terminal receiving a second response from the second core network device.

[0191] The second reply message type can be a session establishment reply or a PDU session establishment reply.

[0192] Optionally, the second response carries a switching indication parameter. The description of this switching indication parameter is the same as in the previous embodiments and will not be repeated.

[0193] It should be understood that, in another possible scenario, the second response may also be used to indicate that the establishment of the second connection has failed. Accordingly, after receiving the indication that the establishment of the second connection has failed, the terminal may not perform subsequent handover processing, or the terminal may initiate a new second request to request the establishment of the second connection again. Here, we will not limit or exhaust all the processing that the terminal may perform.

[0194] Referring to Figure 10, the process of establishing the first and second connections of a terminal under two core networks or two networks is illustrated by an example. In this example, it is assumed that the user plane network elements of the two core networks can be co-located (i.e., the co-located core network user plane network elements (such as a single UPF)), and both core networks can access the same UDM to obtain the subscription information of the same UE. The specific process is as follows:

[0195] Step 1001: The UE (i.e., the terminal) initiates a PDU session establishment request (i.e., the first request). In this example, the UE can be a dual-connectivity UE or a multi-connectivity UE. Specifically, the UE sends a PDU session establishment request to the control plane network element (first core network device such as SMF-1) of core network-1 through base station-1 (first access network device), carrying parameters such as PDU session identifier (i.e., the identifier of the first session) and MBB indication.

[0196] Here, the UE can decide whether to perform MBB on the data of the PDU session (first session) based on the URSP, and then carry the MBB indication in the PDU session establishment request. Alternatively, the UE can decide whether to perform MBB (function) on the data of the PDU session (first session) based on the local configuration.

[0197] Step 1002: The core network-1 control plane network element (SMF-1) interacts with the UDM to obtain subscription information (UE subscription information). Optionally, the subscription information may include "MBB subscription parameters". The core network-1 control plane network element (SMF-1) determines whether to allow the terminal user or the terminal user's PDU session to perform MBB function based on this.

[0198] Step 1003: The core network-1 control plane network element (SMF-1) configures session parameters (i.e., the first relevant parameters of the first session) to the co-located core network user plane network element (UPF).

[0199] Step 1004: The core network-1 control plane element (SMF-1) sends a PDU session establishment reply message (i.e., the first reply) to the UE, which carries an indication parameter (second indication parameter) indicating whether MBB functionality is supported or allowed. Optionally, it may also carry at least one of the following: allowed network information and a token parameter (token parameter associated with the first session). The token parameter is carried during the second PDU session establishment. The allowed network information refers to the network in which the UE determines the establishment of the second leg (i.e., the second connection within the same session). The relevant description of the allowed network information is the same as in the previous embodiment and will not be repeated here.

[0200] Step 1005: If the PDU session establishment reply message received by the UE in step 1004 carries an indication parameter for indicating support or permission of MBB functionality, the UE initiates a second PDU session establishment request (i.e., the second request) when a base station handover is required. Specifically, the UE sends the second PDU session establishment request to the core network-2 control plane network element (i.e., the second core network device, such as SMF-2) through base station-2 (the second access network device), carrying the same PDU session identifier (i.e., the identifier of the first session) and (optionally) a Token parameter.

[0201] Step 1006: The core network-2 control plane element (SMF-2) selects the same core network user plane element (UPF) for this connection establishment based on the PDU session identifier and / or Token parameter.

[0202] Step 1007: The core network-2 control plane element (SMF-2) configures session parameters (i.e., the second related parameters of the first session) to the co-located core network user plane element (UPF). The session parameters configured in this step may include the same PDU session address (such as IP address, MAC address, or Non-IP address) as those configured in step 1003; additionally, the session parameters configured in this step may also include content different from that configured in step 1003, such as at least one of the following: Tunnel ID, TE ID, etc. The explanations regarding the content of the two session parameters are the same as in the aforementioned embodiments, and therefore will not be repeated.

[0203] Step 1008: The core network-2 control plane network element (SMF-2) sends a PDU session establishment reply message (i.e., the second reply) to the UE. The PDU session establishment reply message carries the establishment result and (optionally) a handover flag. The handover flag is used during user plane data transmission handover.

[0204] It should be noted that in actual processing, some steps in the above examples may be optional. For example, step 1007 may be optional; if the first relevant parameter of the first session and the second relevant parameter of the first session are the same, step 1007 may not be executed. For example, step 1008 may be optional; for example, the core network-2 control plane element (SMF-2) may not send a PDU session establishment reply message to the UE, and the UE may default to the second connection being successfully established (or another connection of the first session being successfully established). It should be noted that these are only some possible exemplary illustrations and are not intended to limit or exhaustively describe the embodiments of this application.

[0205] In some possible implementations, after the terminal receives the second reply (which indicates the completion of establishing the second connection), the method further includes: releasing the first connection if the terminal transmits data of the first session with the user plane network element through the second connection.

[0206] Specifically, the terminal's processing may include: establishing a first connection and a second connection of the first session between the terminal and the user plane network element, wherein the first connection is established between the terminal and the user plane network element through a first access network device, and the second connection is established between the terminal and the user plane network element through the second access network device when the terminal needs to switch from the first access network device to a second access network device; and releasing the first connection when the terminal transmits data of the first session with the user plane network element through the second connection. Specifically, the terminal completes the establishment of the second connection and the first connection before transmitting data of the first session with the user plane network element through the second connection. In other words, the terminal needs to receive a second response (or a first response and a second response) before performing the processing of transmitting data of the first session with the user plane network element through the second connection. In this embodiment, the descriptions related to the establishment of the first connection and the second connection of the first session between the terminal and the user plane network element are the same as in the aforementioned embodiments, and therefore will not be repeated.

[0207] Accordingly, the processing of the user plane network element may include: the user plane network element establishing a first connection and a second connection of the first session with the terminal, wherein the first connection is established between the terminal and the user plane network element through a first access network device, and the second connection is established between the terminal and the user plane network element through the second access network device when the terminal needs to switch from the first access network device to the second access network device; and releasing the first connection when the user plane network element transmits the data of the first session with the terminal through the second connection.

[0208] Here, releasing the first connection when the terminal transmits data of the first session with the user plane network element through the second connection can mean releasing the first connection when the terminal transmits uplink data and downlink data of the first session with the user plane network element through the second connection.

[0209] Releasing the first connection when the user plane network element transmits data of the first session with the terminal through the second connection can mean releasing the first connection when the user plane network element transmits uplink data and downlink data of the first session with the terminal through the second connection.

[0210] In one example, the terminal transmits data of the first session with the user plane network element through the second connection, including: when the terminal receives downlink data of the first session from the user plane network element through the second connection, it sends uplink data of the first session to the user plane network element through the second connection.

[0211] Accordingly, the user plane network element transmits data of the first session to the terminal through the second connection, including: the user plane network element sending downlink data of the first session to the terminal through the second connection; and the user plane network element receiving uplink data of the first session from the terminal through the second connection.

[0212] In this example, the timing at which the user plane network element sends the downlink data of the first session to the terminal through the second connection can be any time after the user plane network element completes the establishment of the second connection; that is, in this example, the specific timing for the user plane network element to send the downlink data of the first session to the terminal through the second connection can be determined by the user plane network element. For example, the user plane network element can immediately execute the process of sending the downlink data of the first session to the terminal through the second connection after completing the establishment of the second connection; as another example, the user plane network element can delay the process of sending the downlink data of the first session to the terminal through the second connection for a first duration from the time the second connection is established, and this first duration can be configured according to the actual situation, and is not limited in this embodiment.

[0213] In one example, before the terminal transmits the data of the first session to the user plane network element through the second connection, the method further includes: the terminal sending uplink data of the first session to the user plane network element through the first connection, wherein the uplink data of the first session carries a handover indication parameter, the handover indication parameter being used to indicate switching to the second connection to transmit the data of the first session.

[0214] Accordingly, before the user plane network element transmits the data of the first session to the terminal through the second connection, the method further includes: the user plane network element receiving uplink data of the first session from the terminal through the first connection, wherein the uplink data of the first session carries a handover indication parameter, the handover indication parameter being used to indicate switching to the second connection to transmit the data of the first session.

[0215] In this example, the timing of the terminal sending uplink data of the first session carrying handover indication parameters to the user plane network element via the first connection can be any time after the terminal completes the establishment of the second connection. For example, the terminal can send uplink data of the first session carrying handover indication parameters to the user plane network element immediately after completing the establishment of the second connection; as another example, the terminal can delay for a second duration from the moment the second connection is established before sending uplink data of the first session carrying handover indication parameters to the user plane network element via the first connection. The second duration can be configured according to actual conditions, and it can be the same as or different from the first duration. This embodiment does not limit this.

[0216] The processing after the user plane network element receives uplink data of the first session from the terminal through the first connection may include: if the user plane network element extracts the handover indication parameter from the uplink data of the first session, it determines that the terminal indicates a handover to the second connection to transmit the data of the first session.

[0217] Furthermore, the processing of the user plane network element transmitting data of the first session with the terminal through the second connection further includes: the user plane network element sending downlink data of the first session to the terminal through the second connection; and the user plane network element receiving uplink data of the first session from the terminal through the second connection. Correspondingly, the terminal transmitting data of the first session with the user plane network element through the second connection includes: when the terminal receives downlink data of the first session from the user plane network element through the second connection, it sends uplink data of the first session to the user plane network element through the second connection.

[0218] The timing of the user plane network element sending downlink data of the first session to the terminal via the second connection can be any time after the user plane network element receives uplink data of the first session carrying handover indication parameters. For example, the user plane network element can immediately execute the process of sending downlink data of the first session to the terminal via the second connection after receiving uplink data of the first session carrying handover indication parameters; as another example, the user plane network element can delay for a first duration after receiving uplink data of the first session carrying handover indication parameters before executing the process of sending downlink data of the first session to the terminal via the second connection.

[0219] In one example, the terminal transmits data of the first session with the user plane network element through the second connection, including: the terminal sending uplink data of the first session to the user plane network element through the second connection; and the terminal receiving downlink data of the first session from the user plane network element through the second connection.

[0220] Accordingly, the user plane network element transmits the data of the first session to the terminal through the second connection, including: when the user plane network element receives the uplink data of the first session from the terminal through the second connection, it sends the downlink data of the first session to the terminal through the second connection.

[0221] Optionally, the timing of the terminal sending the uplink data of the first session to the user plane network element through the second connection can be any time after the terminal completes the establishment of the second connection. For example, the terminal may send the uplink data of the first session carrying handover indication parameters to the user plane network element immediately after completing the establishment of the second connection; as another example, the terminal may send the uplink data of the first session carrying handover indication parameters to the user plane network element after a second delay from the time the second connection is established.

[0222] Similar to the previous example, the timing of the user plane network element sending downlink data of the first session to the terminal through the second connection can also be any time after the user plane network element receives uplink data of the first session through the second connection. For example, the user plane network element can immediately execute the process of sending downlink data of the first session to the terminal through the second connection after receiving uplink data of the first session carrying handover indication parameters; as another example, the user plane network element can delay for a first time period after receiving uplink data of the first session carrying handover indication parameters before executing the process of sending downlink data of the first session to the terminal through the second connection.

[0223] Optionally, the uplink data of the first session carries a handover indication parameter, which is used to indicate a switch to the second connection to transmit the data of the first session.

[0224] Specifically, the terminal sends uplink data of the first session carrying handover indication parameters to the user plane network element through the second connection; the terminal receives downlink data of the first session from the user plane network element through the second connection. Correspondingly, when the user plane network element receives uplink data of the first session carrying handover indication parameters from the terminal through the second connection, it sends downlink data of the first session to the terminal through the second connection.

[0225] The timing at which the terminal sends uplink data of the first session carrying handover indication parameters to the user plane network element via the second connection can be any time after the terminal has completed establishing the second connection.

[0226] The processing after the user plane network element receives uplink data of the first session from the terminal through the second connection may include: if the user plane network element extracts the handover indication parameter from the uplink data of the second session, it determines that the terminal indicates a handover to the second connection to transmit the data of the first session.

[0227] The timing at which the user plane network element sends downlink data of the first session to the terminal through the second connection can be any time after the user plane network element receives uplink data of the first session carrying handover indication parameters, which will not be repeated here.

[0228] On the terminal side, the process of releasing the first connection may include: the terminal initiating a session release procedure to the first core network device through the first access network device to release the first connection while retaining the second connection. Specifically, this process may include: the terminal sending a session release request to the first core network device through the first access network device, which requests the release of the first connection; and upon receiving a session release notification from the first core network device through the first access network device, determining to release the first connection, whereby the terminal confirms that the user plane network element is releasing the first connection. On the terminal side, when releasing the first connection, the second connection is still retained. Therefore, at this time, the terminal side completes the switch from the first connection to the second connection to transmit uplink and downlink data of the first session.

[0229] The processing of the session release procedure by the first core network device may include: receiving a session release request from the terminal through the first access network device, and sending a release instruction to the user plane network element, the release instruction being used to instruct the user plane network element to release the first connection; and, upon receiving a resource release notification from the user plane network element, sending a session release notification to the terminal through the first access network device, wherein the resource release notification is used by the first core network device to determine the resources related to the release of the first connection by the user plane network element, and the session release notification is used by the terminal to determine that the user plane network element is releasing the first connection.

[0230] On the user plane network element side, the process of releasing the first connection may include: releasing the first connection when the user plane network element receives a release instruction from the first core network device. Further, the user plane network element releasing the first connection may refer to releasing resources related to the first connection; after completing the release of the first connection, the user plane network element may also send a resource release notification to the first core network device, which is used by the first core network device to determine whether the user plane network element is releasing resources related to the first connection.

[0231] In this embodiment, the first access network device and the second access network device can be different access network devices under the same core network. The following is an exemplary description of the data handover process performed on the user plane under the same core network or the same network, with reference to Figure 11:

[0232] Step 1101: The UE initiates the establishment of a PDU session with the core network user plane element for the first time through base station-1 (i.e., establishing the first connection of the first session). The relevant processing for establishing this first PDU session is the same as the processing for establishing the first connection of the first session in the previous embodiments, for example, it can be the same as steps 901 to 904 shown in Figure 9, so it will not be described in detail. After completing step 1101, the UE's uplink (UL) data and downlink (DL) data (i.e., the uplink data and downlink data of the first session) are both transmitted through base station-1.

[0233] Step 1102: When the UE needs to perform a cross-base station handover, the UE initiates a second PDU session establishment with the core network user plane element through base station-2 (i.e., establishing a second connection for the first session). The relevant processing for establishing this second PDU session is the same as the processing for establishing a second connection for the first session in the aforementioned embodiments. For example, it can be the same as steps 905 to 908 shown in Figure 9, so it will not be described in detail.

[0234] In the following example steps, for the sake of brevity, the connection corresponding to the PDU session requested in step 1101, i.e., the first connection of the first session, will be referred to as the first leg, and the connection corresponding to the PDU session requested in step 1102, i.e., the second connection of the first session, will be referred to as the second leg. The explanation will not be repeated below.

[0235] After completing step 1102, the UE and the core network user plane network element (such as UPF) can switch data transmission between the UE and the core network user plane element (such as UPF) in one of the following three optional methods (that is, switch the transmission of DL data (DL data and UL data) from base station-1 to base station-2):

[0236] Option -1: After the second leg is successfully established, the core network user plane element sends DL data to the UE via base station -2 at an opportune time; after receiving the DL data transmitted by the second leg, the UE sends UL data via the second leg. Here, the core network user plane element can either start sending DL data via base station -2 immediately after the second leg is successfully established, or delay for a first duration after the second leg is successfully established before starting to send DL data via base station -2.

[0237] Option 2: After the second leg is successfully established, the UE sends a handover flag through base station-1 or base station-2 (Figure 11 shows the first leg where base station-1 is located). This handover flag can be carried by the UL data packet. After receiving the handover flag, the core network user plane element sends DL data through the second leg.

[0238] Option -3: The core network user plane element receives UL data sent by the UE through the second leg (the second leg where base station-2 is located), and the core network user plane element sends DL data through the second leg.

[0239] Step 1103: When both UL and DL data are transmitted through base station-2 (i.e., the second leg), the UE initiates a PDU session release procedure through base station-1 at an opportune time to release the first leg and retain the second leg.

[0240] In this embodiment, the first access network device and the second access network device can be different access network devices under the same core network. The following is an exemplary description of the data handover process performed on the user plane under different core networks or different networks, with reference to Figure 12:

[0241] In step 1201, the UE initiates a PDU session establishment (i.e., establishes the first connection of the first session) with the co-located core network user plane element through base station-1 (the base station corresponding to core network-1). The related processing for this first PDU session establishment is the same as the processing for establishing the first connection of the first session in the aforementioned embodiments, for example, it can be the same as steps 1001 to 1004 shown in Figure 10, so it will not be described in detail. After completing step 1201, the UE's uplink (UL) data and downlink (DL) data (i.e., the uplink data and downlink data of the first session) are both transmitted through base station-1.

[0242] Step 1202: When the UE needs to perform a cross-base station handover, the UE initiates a second PDU session establishment with the co-located core network user plane network element through base station-2 (the base station corresponding to core network-2) (i.e., establishing a second connection for the first session). The relevant processing for establishing this second PDU session is the same as the processing for establishing a second connection for the first session in the aforementioned embodiments. For example, it can be the same as steps 1005 to 1008 shown in Figure 10, so it will not be described in detail.

[0243] In the following example steps, the connection corresponding to the PDU session requested to be established in step 1201, i.e., the first connection of the first session, is referred to as the first leg, and the connection corresponding to the PDU session requested to be established in step 1202, i.e., the second connection of the first session, is referred to as the second leg.

[0244] After completing step 1202, the UE and the co-located core network user plane network element (such as UPF) can switch data transmission between the UE and the base station using one of the following three optional methods (i.e., switch DL data (DL data and UL data) from base station-1 to base station-2 for transmission):

[0245] Option-1: After the second leg is successfully established, the co-located core network user plane element will send DL data to the UE via base station-2 at an opportune time; after receiving the DL data transmitted by the second leg, the UE will send UL data via the second leg. Here, the co-located core network user plane element can either start sending DL data via base station-2 immediately after the second leg is successfully established, or delay for a first duration after the second leg is successfully established before starting to send DL data via base station-2.

[0246] Option 2: After the second leg is successfully established, the UE sends a handover flag through base station-1 or base station-2 (Figure 12 shows the handover flag sent through the second leg where base station-2 is located). The handover flag can be carried by the UL data packet. After receiving the handover flag, the co-located core network user plane element sends DL data through the second leg.

[0247] Option-3: The co-located core network user plane element receives UL data sent by the UE through the second leg (the second leg where base station-2 is located), and the core network user plane element sends DL data through the second leg.

[0248] The explanation of step 1203 is the same as that of step 1103 shown in Figure 11, and will not be repeated.

[0249] Finally, considering the relevant technologies, in the 5G era, NG-RAN (Radio Access Network) can include scenarios where gNB and eNB simultaneously or separately access the 5GC core network. For NG-RAN, the Handover Require message sent by gNB and eNB to AMF is the same. When the Target ID in the sent message is the eNB ID and the eNB is connected to both 5GC and EPC, AMF currently cannot determine whether to perform RAT handover (5GC remains unchanged, base station access changes from NR to eNB) or System handover (5GC changes to EPC).

[0250] In scenarios with an N26 interface, if the UE is in a connected state, the NG-RAN determines the timing of handover triggering based on a measurement threshold. When the NG-RAN decides to trigger handover, it sends a Handover Required command to the core network AMF. The core network prepares resources with the peer core network, and then the NG-RAN triggers a Handover Command request to switch the UE to the peer network. If the UE is in an idle state, it sends a TAU Request (Tracking Area Update Request) to the target core network MME (Mobility Management Entity). The MME is responsible for obtaining relevant context information from the original core network and completing the location update process in the target core network.

[0251] In the case of cross-system handover between 5GC and EPC, if there is no N26 interface, the UE's behavior is defined as two types:

[0252] If the UE can recognize the "Support N26-less handover" instruction sent by the network side, the UE will execute "Attach with Handover flag" and carry the APN / DNN corresponding to the PDU Session in the 5GS. This message will trigger the network side to look up the co-located network element SMF+PGW-C (PDN Gateway-Control Plane), UPF+PGW-U (PDN Gateway-User Plane), and PCF+PCRF (Policy and Charging Rules Function) based on the APN / DNN used by the UE. This allows the co-located network element to map the 4G SM context (Session Management Context), achieving consistency of session IP addresses.

[0253] If the UE does not recognize the "Support Handover Without N26" instruction sent by the network, it will directly make a Tracking Area Update request. At this time, if the network does not support the N26 interface, it will cause the network to send a TAU Reject message to the UE, and then the UE will initiate a normal Attach procedure. In this case, the consistency of the session's IP address cannot be guaranteed.

[0254] The process of inter-base station handover within the same core network based on the Xn interface can include: In the preparation and execution phase of air interface handover: the source base station and the target base station complete the handover process through the Xn interface, and the UE switches the air interface connection to the target base station; the target base station sends a path switch to the core network control plane, and the core network control plane network elements then interact with the user plane network elements to switch the downlink data flow to the N3 path corresponding to the target base station; finally, the registration update process is executed (optional).

[0255] As can be seen from the above explanation of the relevant technologies, the switching process of the relevant technologies is all about releasing before switching. In other words, there will be a period of idle time in the transmission of terminal data. During this period of idle time, no UL data and DL data can be transmitted, which is unacceptable for latency-sensitive services.

[0256] The above-described solution provided in this application, when the terminal sends a first request to establish a first connection of a first session with a user plane network element through a first access network device, carries a first indication parameter in the first request to instruct the terminal to request the subsequent execution of a first function for the currently established first session. The first function is the function of maintaining multiple connections of the same session with the user plane network element through multiple access network devices during cross-access network device handover. In this way, by enhancing the session establishment process, a foundation is provided for the subsequent establishment of a second connection of the first session, enabling the terminal to maintain multiple connections of the same session for a period of time during the cross-access network device handover process. This ensures that the terminal will not experience any situation where it is unable to transmit uplink and downlink data, thereby realizing a handover mechanism of establishing first and then disconnecting, that is, achieving seamless handover of uplink and downlink data.

[0257] The above-described solution provided in this application allows the terminal and user plane network element to establish a first connection for a first session through a first access network device, and a first session and a second connection through a second access network device. The second connection is established when the terminal needs to switch from the first access network device to the second access network device. The first connection is only released when the terminal and user plane network element transmit data from the first session through the second connection. Thus, when the terminal needs to switch across access network devices, establishing a second connection for the first session while maintaining the first connection ensures that the terminal and user plane network element can maintain multiple connections within the same session for a period of time. The first connection of the session is released only after both the terminal and user plane network element have transmitted data through the second connection. This ensures that the terminal will not experience any inability to transmit uplink or downlink data at any time, realizing the MMB handover mechanism, i.e., achieving seamless handover of uplink and downlink data.

[0258] Figure 13 is a schematic diagram of the composition structure of a terminal according to an embodiment of this application, including:

[0259] The first communication unit 1301 is configured to send a first request through a first access network device, wherein the first request is configured to request the establishment of a first connection of a first session with a user plane network element through the first access network device, the first request carries a first indication parameter, the first indication parameter is configured to instruct the terminal to request the execution of a first function for the first session, the first function being the function of the terminal maintaining multiple connections of the same session with the user plane network element through multiple access network devices when it needs to switch across access network devices.

[0260] The first communication unit is configured to receive a first routing identifier (RSD), wherein the first RSD includes the first indication parameter.

[0261] The first session is the session corresponding to the first RSD.

[0262] The cross-access network device handover includes at least one of the following: handover between different access network devices under the same core network, and handover between different access network devices under different core networks.

[0263] The first request also carries the identifier of the first session.

[0264] The first communication unit is configured to receive a first response, wherein the first response is configured to indicate that the first connection has been established, and the first response carries a second indication parameter, the second indication parameter being configured to indicate whether the terminal is supported or allowed to perform the first function.

[0265] The first response also carries at least one of the following: a token parameter associated with the first session, or allowed network information, wherein the allowed network information is used by the terminal to determine the networks permitted for establishing the second connection of the first session.

[0266] The first communication unit is configured to send a second request through the second access network device when a switch from the first access network device to the second access network device is required. The second request is used to request the establishment of a second connection of the first session with the user plane network element through the second access network device.

[0267] The second request carries at least one of the following: the identifier of the first session, and the token parameter associated with the first session.

[0268] The first communication unit is configured to receive a second response, wherein the second response is configured to indicate that the establishment of the second connection has been completed.

[0269] The second response carries a switching indication parameter.

[0270] The first communication unit is configured to release the first connection when transmitting data of the first session with the user plane network element through the second connection.

[0271] The first communication unit is configured to send uplink data of the first session to the user plane network element via the second connection when receiving downlink data of the first session from the user plane network element via the second connection.

[0272] The first communication unit is configured to send uplink data of a first session to the user plane network element through the first connection, wherein the uplink data of the first session carries a handover indication parameter, the handover indication parameter being used to indicate a handover to the second connection for transmitting the data of the first session.

[0273] The first communication unit is configured to send uplink data of the first session to the user plane network element via the second connection; and to receive downlink data of the first session from the user plane network element via the second connection.

[0274] The uplink data of the first session carries a handover indication parameter, which is used to indicate a switch to the second connection to transmit the data of the first session.

[0275] Figure 14 is a schematic diagram of the composition structure of a first core network device according to an embodiment of this application, including:

[0276] The second communication unit 1401 is configured to receive a first request from a terminal through a first access network device. The first request is configured to request the establishment of a first connection of a first session with a user plane network element through the first access network device. The first request carries a first indication parameter, which is configured to instruct the terminal to request the execution of a first function for the first session. The first function is the function of the terminal maintaining multiple connections of the same session with the user plane network element through multiple access network devices when it needs to switch across access network devices.

[0277] The cross-access network device handover includes at least one of the following: handover between different access network devices under the same core network, and handover between different access network devices under different core networks.

[0278] The first request also carries the identifier of the first session.

[0279] The second communication unit is configured to send a first response to the terminal, wherein the first response is configured to indicate that the first connection has been established, and the first response carries a second indication parameter, the second indication parameter being configured to indicate whether the terminal is supported or allowed to perform the first function.

[0280] As shown in Figure 14, the first core network device further includes:

[0281] The second processing unit 1402 is used to determine the second indication parameter based on the subscription information of the terminal.

[0282] The first response also carries at least one of the following: a token parameter associated with the first session, or allowed network information, wherein the allowed network information is used by the terminal to determine the networks permitted for establishing the second connection of the first session.

[0283] The second communication unit is configured to receive a second request from the terminal via a second access network device, wherein the second request is configured to request the establishment of a second connection of the first session with the user plane network element via the second access network device.

[0284] The second request carries at least one of the following: the identifier of the first session, and the token parameter associated with the first session.

[0285] The second processing unit is used to determine the user plane network element based on the identifier of the first session and / or the token parameter associated with the first session.

[0286] The second communication unit is used to send a second reply to the terminal, wherein the second reply is used to indicate that the second connection has been established.

[0287] The second response carries a switching indication parameter.

[0288] Figure 15 is a schematic diagram of the composition structure of a second core network device according to an embodiment of this application, including:

[0289] The third communication unit 1501 is configured to receive a second request from a terminal via the second access network device, wherein the second request is configured to request the establishment of a second connection of a first session with a user plane network element via the second access network device.

[0290] The second request carries at least one of the following: the identifier of the first session, and the token parameter associated with the first session.

[0291] As shown in Figure 15, the second core network device also includes:

[0292] The third processing unit 1502 is used to determine the user plane network element based on the identifier of the first session and / or the token parameter associated with the first session.

[0293] The third communication unit is used to send a second reply to the terminal, wherein the second reply is used to indicate that the second connection has been established.

[0294] The second response carries a switching indication parameter.

[0295] In some possible implementations, a terminal includes:

[0296] The first communication unit is used to establish a first connection and a second connection of the first session with a user plane network element, wherein the first connection is established between the terminal and the user plane network element through a first access network device, and the second connection is established between the terminal and the user plane network element through the second access network device when the terminal needs to switch from the first access network device to the second access network device; when transmitting data of the first session with the user plane network element through the second connection, the first connection is released.

[0297] The first communication unit is configured to send uplink data of the first session to the user plane network element via the second connection when receiving downlink data of the first session from the user plane network element via the second connection.

[0298] The first communication unit is configured to send uplink data of a first session to the user plane network element through the first connection, wherein the uplink data of the first session carries a handover indication parameter, the handover indication parameter being used to indicate a handover to the second connection for transmitting the data of the first session.

[0299] The first communication unit is configured to send uplink data of the first session to the user plane network element via the second connection; and to receive downlink data of the first session from the user plane network element via the second connection.

[0300] The uplink data of the first session carries a handover indication parameter, which is used to indicate a switch to the second connection to transmit the data of the first session.

[0301] Figure 16 is a schematic diagram of the composition structure of a user plane network element according to an embodiment of this application, including:

[0302] The fourth communication unit 1601 is used to establish a first connection and a second connection of the first session with the terminal, wherein the first connection is established between the terminal and the user plane network element through the first access network device, and the second connection is established between the terminal and the user plane network element through the second access network device when the terminal needs to switch from the first access network device to the second access network device; when transmitting data of the first session with the terminal through the second connection, the first connection is released.

[0303] The fourth communication unit is used to send downlink data of the first session to the terminal through the second connection; and to receive uplink data of the first session from the terminal through the second connection.

[0304] The fourth communication unit is configured to receive uplink data of the first session from the terminal via the first connection, wherein the uplink data of the first session carries a handover indication parameter, the handover indication parameter being used to indicate switching to the second connection to transmit the data of the first session.

[0305] The fourth communication unit is configured to send downlink data of the first session to the terminal via the second connection when receiving uplink data of the first session from the terminal via the second connection.

[0306] The uplink data of the first session carries a handover indication parameter, which is used to indicate a switch to the second connection to transmit the data of the first session.

[0307] The device in this application embodiment can realize the corresponding functions of the devices in the foregoing configuration method embodiments. The processes, functions, implementation methods, and beneficial effects of each module (sub-module, unit, or component, etc.) in this device can be found in the corresponding descriptions in the above method embodiments, and will not be repeated here. It should be noted that the functions described for each module (sub-module, unit, or component, etc.) in the device of this application embodiment can be implemented by different modules (sub-modules, units, or components, etc.) or by the same module (sub-module, unit, or component, etc.).

[0308] Figure 17 is a schematic structural diagram of a communication device 1700 according to an embodiment of this application. The communication device 1700 includes a processor 1710, which can call and run computer programs from a memory to enable the communication device 1700 to implement the methods in the embodiments of this application. In one possible implementation, the communication device 1700 may further include a memory 1720. The processor 1710 can call and run computer programs from the memory 1720 to enable the communication device 1700 to implement the methods in the embodiments of this application. The memory 1720 may be a separate device independent of the processor 1710, or it may be integrated into the processor 1710. In one possible implementation, the communication device 1700 may further include a transceiver 1730, which the processor 1710 can control to communicate with other devices. Specifically, it can send information or data to other devices, or receive information or data sent by other devices. The transceiver 1730 may include a transmitter and a receiver. The transceiver 1730 may further include antennas, and the number of antennas may be one or more.

[0309] In one possible implementation, the communication device 1700 may be a terminal, a first core network device, a second core network device, or a user plane network element in the embodiments of this application. The communication device 1700 may implement the corresponding processes implemented by the terminal, the first core network device, the second core network device, or the user plane network element in the various methods of the embodiments of this application. For the sake of brevity, these will not be described in detail here.

[0310] Figure 18 is a schematic structural diagram of a chip 1800 according to an embodiment of this application. The chip 1800 includes a processor 1810, which can call and run computer programs from memory to implement the methods in the embodiments of this application. In one possible implementation, the chip 1800 may further include a memory 1820. The processor 1810 can call and run computer programs from the memory 1820 to implement the methods executed by a terminal, a first core network device, a second core network device, or a user plane network element in the embodiments of this application. The memory 1820 may be a separate device independent of the processor 1810, or it may be integrated into the processor 1810. In one possible implementation, the chip 1800 may further include an input interface 1830. The processor 1810 can control the input interface 1830 to communicate with other devices or chips; specifically, it can acquire information or data sent by other devices or chips. In one possible implementation, the chip 1800 may further include an output interface 1840. The processor 1810 can control the output interface 1840 to communicate with other devices or chips, specifically, it can output information or data to other devices or chips.

[0311] In one possible implementation, the chip can be applied to the terminal, the first core network device, the second core network device, or the user plane network element in the embodiments of this application. The chip can implement the corresponding processes implemented by the terminal, the first core network device, the second core network device, or the user plane network element in the various methods of the embodiments of this application. For simplicity, these details will not be elaborated further here. It should be understood that the chip mentioned in the embodiments of this application can also be called a system-on-a-chip (SoC), system-on-a-chip (SoC), chip system, or system-on-chip, etc. The processor mentioned above can be a general-purpose processor, a digital signal processor (DSP), a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), or other programmable logic devices, transistor logic devices, discrete hardware components, etc. The general-purpose processor mentioned above can be a microprocessor or any conventional processor, etc. The memory mentioned above can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM). It should be understood that the above-described memory is exemplary but not limiting. For example, the memory in the embodiments of this application can also be static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct memory bus RAM (DR RAM), etc. In other words, the memory in the embodiments of this application is intended to include, but is not limited to, these and any other suitable types of memory.

[0312] Figure 19 is a schematic block diagram of a communication system 1900 according to an embodiment of this application. The communication system 1900 includes a terminal 1910, a first core network device 1920, a second core network device 1930, and a user plane network element 1904. The terminal 1910 can be used to implement the corresponding functions implemented by the terminal in the above method. The first core network device 1920 can be used to implement the corresponding functions implemented by the first core network device in the above method. The second core network device 1930 can be used to implement the corresponding functions implemented by the second core network device in the above method. The user plane network element 1904 can be used to implement the corresponding functions implemented by the user plane network element in the above method. For simplicity, further details are omitted here.

[0313] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. This computer program product includes one or more computer instructions. When these computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives (SSDs)).

[0314] It should be understood that in the various embodiments of this application, the sequence number of each process does not imply 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 this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. The above descriptions are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication method, comprising: The terminal sends a first request through a first access network device, wherein the first request is used to request the establishment of a first connection of a first session with a user plane network element through the first access network device, the first request carries a first indication parameter, the first indication parameter is used to instruct the terminal to request the execution of a first function for the first session, the first function is the function of the terminal maintaining multiple connections of the same session with the user plane network element through multiple access network devices when it needs to switch across access network devices.

2. The method according to claim 1, wherein, Before the terminal sends the first request through the first access network device, it also includes: The terminal receives a first routing identifier (RSD), wherein the first RSD includes the first indication parameter.

3. The method according to claim 2, wherein, The first session is the session corresponding to the first RSD.

4. The method according to any one of claims 1-3, wherein, The cross-access network device handover includes at least one of the following: handover between different access network devices under the same core network, and handover between different access network devices under different core networks.

5. The method according to any one of claims 1-4, wherein, The first request also carries the identifier of the first session.

6. The method according to any one of claims 1-5, wherein, After the terminal sends the first request through the first access network device, it further includes: The terminal receives a first response, wherein the first response is used to indicate that the first connection has been established, and the first response carries a second indication parameter, which is used to indicate whether the terminal is supported or allowed to perform the first function.

7. The method according to claim 6, wherein, The first response also carries at least one of the following: a token parameter associated with the first session, or allowed network information, wherein the allowed network information is used by the terminal to determine the networks permitted for establishing the second connection of the first session.

8. The method according to claim 6 or 7, wherein, After receiving the first reply, the terminal also includes: When the terminal needs to switch from the first access network device to the second access network device, the terminal sends a second request through the second access network device, wherein the second request is used to request the establishment of a second connection of the first session with the user plane network element through the second access network device.

9. The method according to claim 8, wherein, The second request carries at least one of the following: the identifier of the first session, and the token parameter associated with the first session.

10. The method according to claim 8 or 9, wherein, After the terminal sends the second request through the second access network device, it further includes: The terminal receives a second response, wherein the second response is used to indicate that the second connection has been established.

11. The method according to claim 10, wherein, The second response carries a switching indication parameter.

12. The method according to claim 10 or 11, wherein, After receiving the second reply, the terminal also includes: When the terminal transmits data of the first session with the user plane network element through the second connection, the first connection is released.

13. The method according to claim 12, wherein, The terminal transmits data of the first session to the user plane network element through the second connection, including: When the terminal receives downlink data of the first session from the user plane network element through the second connection, it sends uplink data of the first session to the user plane network element through the second connection.

14. The method according to claim 13, wherein, Before the terminal transmits the data of the first session to the user plane network element through the second connection, it further includes: The terminal sends uplink data of the first session to the user plane network element through the first connection, wherein the uplink data of the first session carries a handover indication parameter, which is used to indicate handover to the second connection to transmit the data of the first session.

15. The method according to claim 12, wherein, The terminal transmits data of the first session to the user plane network element through the second connection, including: The terminal sends the uplink data of the first session to the user plane network element through the second connection; The terminal receives downlink data from the user plane network element of the first session via the second connection.

16. The method according to claim 15, wherein, The uplink data of the first session carries a handover indication parameter, which is used to indicate a switch to the second connection to transmit the data of the first session.

17. A communication method, comprising: The first core network device receives a first request from the terminal through the first access network device. The first request is used to request the establishment of a first connection of a first session with the user plane network element through the first access network device. The first request carries a first indication parameter, which is used to instruct the terminal to request the execution of a first function for the first session. The first function is the function of the terminal maintaining multiple connections of the same session with the user plane network element through multiple access network devices when it needs to switch across access network devices.

18. The method according to claim 17, wherein, The cross-access network device handover includes at least one of the following: handover between different access network devices under the same core network, and handover between different access network devices under different core networks.

19. The method according to claim 17 or 18, wherein, The first request also carries the identifier of the first session.

20. The method according to any one of claims 17-19, wherein, After the first core network device receives the first request from the terminal through the first access network device, it further includes: The first core network device sends a first response to the terminal, wherein the first response is used to indicate that the first connection has been established, and the first response carries a second indication parameter, which is used to indicate whether the terminal is supported or allowed to perform the first function.

21. The method according to claim 20, wherein, Before the first core network device sends the first reply to the terminal, it also includes: The first core network device determines the second indication parameter based on the terminal's subscription information.

22. The method according to claim 20 or 21, wherein, The first response also carries at least one of the following: a token parameter associated with the first session, or allowed network information, wherein the allowed network information is used by the terminal to determine the networks permitted for establishing the second connection of the first session.

23. The method according to any one of claims 20-22, wherein, After the first core network device sends the first reply to the terminal, it also includes: The first core network device receives a second request from the terminal through the second access network device, wherein the second request is used to request the establishment of a second connection of the first session with the user plane network element through the second access network device.

24. The method according to claim 23, wherein, The second request carries at least one of the following: the identifier of the first session, and the token parameter associated with the first session.

25. The method according to claim 24, wherein, After the first core network device receives the second request from the terminal through the second access network device, it further includes: The first core network device determines the user plane network element based on the identifier of the first session and / or the token parameters associated with the first session.

26. The method of claim 25, wherein, After determining the user plane network element, the method further includes: The first core network device sends a second response to the terminal, wherein the second response is used to indicate that the second connection has been established.

27. The method according to claim 26, wherein, The second response carries a switching indication parameter.

28. A communication method, comprising: The second core network device receives a second request from the terminal through the second access network device, wherein the second request is used to request the establishment of a second connection of the first session with the user plane network element through the second access network device.

29. The method according to claim 28, wherein, The second request carries at least one of the following: the identifier of the first session, and the token parameter associated with the first session.

30. The method according to claim 29, wherein, After receiving the second request from the terminal through the second access network device, the second core network device further includes: The second core network device determines the user plane network element based on the identifier of the first session and / or the token parameters associated with the first session.

31. The method according to claim 30, wherein, After determining the user plane network element, the method further includes: The second core network device sends a second response to the terminal, wherein the second response is used to indicate that the establishment of the second connection has been completed.

32. The method according to claim 31, wherein, The second response carries a switching indication parameter.

33. A communication method, comprising: The terminal establishes a first connection and a second connection of the first session with a user plane network element, wherein the first connection is established between the terminal and the user plane network element through a first access network device, and the second connection is established between the terminal and the user plane network element through the second access network device when the terminal needs to switch from the first access network device to the second access network device; When the terminal transmits data of the first session with the user plane network element through the second connection, the first connection is released.

34. The method according to claim 33, wherein, The terminal transmits data of the first session with the user plane network element through the second connection, including: When the terminal receives downlink data of the first session from the user plane network element through the second connection, it sends uplink data of the first session to the user plane network element through the second connection.

35. The method according to claim 34, wherein, Before the terminal transmits the data of the first session with the user plane network element through the second connection, it further includes: The terminal sends uplink data of the first session to the user plane network element through the first connection, wherein the uplink data of the first session carries a handover indication parameter, which is used to indicate handover to the second connection to transmit the data of the first session.

36. The method according to claim 33, wherein, The terminal transmits data of the first session with the user plane network element through the second connection, including: The terminal sends the uplink data of the first session to the user plane network element through the second connection; The terminal receives downlink data from the first session of the user plane network element through the second connection.

37. The method according to claim 36, wherein, The uplink data of the first session carries a handover indication parameter, which is used to indicate a switch to the second connection to transmit the data of the first session.

38. A communication method, comprising: The user plane network element establishes a first connection and a second connection of the first session with the terminal, wherein the first connection is established between the terminal and the user plane network element through a first access network device, and the second connection is established between the terminal and the user plane network element through the second access network device when the terminal needs to switch from the first access network device to the second access network device; When the user plane network element transmits the data of the first session to the terminal through the second connection, the first connection is released.

39. The method according to claim 38, wherein, The user plane network element transmits data of the first session with the terminal through the second connection, including: The user plane network element sends downlink data of the first session to the terminal through the second connection; The user plane network element receives uplink data from the first session of the terminal through the second connection.

40. The method according to claim 39, wherein, Before the user plane network element transmits the data of the first session with the terminal through the second connection, it further includes: The user plane network element receives uplink data of the first session from the terminal through the first connection, wherein the uplink data of the first session carries a handover indication parameter, which is used to indicate handover to the second connection to transmit the data of the first session.

41. The method according to claim 38, wherein, The user plane network element transmits data of the first session with the terminal through the second connection, including: When the user plane network element receives uplink data of the first session from the terminal through the second connection, it sends downlink data of the first session to the terminal through the second connection.

42. The method according to claim 41, wherein, The uplink data of the first session carries a handover indication parameter, which is used to indicate a switch to the second connection to transmit the data of the first session.

43. A terminal, comprising: The first communication unit is configured to send a first request through a first access network device, wherein the first request is configured to request the establishment of a first connection of a first session with a user plane network element through the first access network device, the first request carries a first indication parameter, the first indication parameter is configured to instruct the terminal to request the execution of a first function for the first session, the first function being the function of the terminal maintaining multiple connections of the same session with the user plane network element through multiple access network devices when it needs to switch across access network devices.

44. The terminal according to claim 43, wherein, The first communication unit is configured to receive a first routing identifier (RSD), wherein the first RSD includes the first indication parameter.

45. The terminal according to claim 44, wherein, The first session is the session corresponding to the first RSD.

46. ​​The terminal according to any one of claims 43-45, wherein, The cross-access network device handover includes at least one of the following: handover between different access network devices under the same core network, and handover between different access network devices under different core networks.

47. The terminal according to any one of claims 43-46, wherein, The first request also carries the identifier of the first session.

48. The terminal according to any one of claims 43-47, wherein, The first communication unit is configured to receive a first response, wherein the first response is configured to indicate that the first connection has been established, and the first response carries a second indication parameter, the second indication parameter being configured to indicate whether the terminal is supported or allowed to perform the first function.

49. The terminal according to claim 48, wherein, The first response also carries at least one of the following: a token parameter associated with the first session, or allowed network information, wherein the allowed network information is used by the terminal to determine the networks permitted for establishing the second connection of the first session.

50. The terminal according to claim 48 or 49, wherein, The first communication unit is configured to send a second request through the second access network device when a switch from the first access network device to the second access network device is required. The second request is used to request the establishment of a second connection of the first session with the user plane network element through the second access network device.

51. The terminal according to claim 50, wherein, The second request carries at least one of the following: the identifier of the first session, and the token parameter associated with the first session.

52. The terminal according to claim 50 or 51, wherein, The first communication unit is configured to receive a second response, wherein the second response is configured to indicate that the establishment of the second connection has been completed.

53. The terminal according to claim 52, wherein, The second response carries a switching indication parameter.

54. The terminal according to claim 52 or 53, wherein, The first communication unit is configured to release the first connection when transmitting data of the first session with the user plane network element through the second connection.

55. The terminal according to claim 54, wherein, The first communication unit is configured to send uplink data of the first session to the user plane network element via the second connection when receiving downlink data of the first session from the user plane network element via the second connection.

56. The terminal according to claim 55, wherein, The first communication unit is configured to send uplink data of a first session to the user plane network element through the first connection, wherein the uplink data of the first session carries a handover indication parameter, the handover indication parameter being used to indicate a handover to the second connection for transmitting the data of the first session.

57. The terminal according to claim 54, wherein, The first communication unit is configured to send uplink data of the first session to the user plane network element via the second connection; and to receive downlink data of the first session from the user plane network element via the second connection.

58. The terminal according to claim 57, wherein, The uplink data of the first session carries a handover indication parameter, which is used to indicate a switch to the second connection to transmit the data of the first session.

59. A first core network device, comprising: The second communication unit is configured to receive a first request from a terminal via a first access network device. The first request is configured to request the establishment of a first connection of a first session with a user plane network element via the first access network device. The first request carries a first indication parameter, which is configured to instruct the terminal to request the execution of a first function for the first session. The first function is the function of maintaining multiple connections of the same session between the terminal and the user plane network element through multiple access network devices when the terminal needs to switch across access network devices.

60. The first core network device according to claim 59, wherein, The cross-access network device handover includes at least one of the following: handover between different access network devices under the same core network, and handover between different access network devices under different core networks.

61. The first core network device according to claim 59 or 60, wherein, The first request also carries the identifier of the first session.

62. The first core network device according to any one of claims 59-61, wherein, The second communication unit is configured to send a first response to the terminal, wherein the first response is configured to indicate that the first connection has been established, and the first response carries a second indication parameter, the second indication parameter being configured to indicate whether the terminal is supported or allowed to perform the first function.

63. The first core network device according to claim 62, further comprising: The second processing unit is used to determine the second indication parameter based on the subscription information of the terminal.

64. The first core network device according to claim 62 or 63, wherein, The first response also carries at least one of the following: a token parameter associated with the first session, or allowed network information, wherein the allowed network information is used by the terminal to determine the networks permitted for establishing the second connection of the first session.

65. The first core network device according to any one of claims 62-64, wherein, The second communication unit is configured to receive a second request from the terminal via a second access network device, wherein the second request is configured to request the establishment of a second connection of the first session with the user plane network element via the second access network device.

66. The first core network device according to claim 65, wherein, The second request carries at least one of the following: the identifier of the first session, and the token parameter associated with the first session.

67. The first core network device according to claim 66, wherein, The second processing unit is used to determine the user plane network element based on the identifier of the first session and / or the token parameter associated with the first session.

68. The first core network device according to claim 67, wherein, The second communication unit is used to send a second reply to the terminal, wherein the second reply is used to indicate that the second connection has been established.

69. The first core network device according to claim 68, wherein, The second response carries a switching indication parameter.

70. A second core network device, comprising: The third communication unit is configured to receive a second request from the terminal via the second access network device, wherein the second request is configured to request the establishment of a second connection of the first session with the user plane network element via the second access network device.

71. The second core network device according to claim 70, wherein, The second request carries at least one of the following: the identifier of the first session, and the token parameter associated with the first session.

72. The second core network device according to claim 71, further comprising: The third processing unit is used to determine the user plane network element based on the identifier of the first session and / or the token parameter associated with the first session.

73. The second core network device according to claim 72, wherein, The third communication unit is used to send a second reply to the terminal, wherein the second reply is used to indicate that the second connection has been established.

74. The second core network device according to claim 73, wherein, The second response carries a switching indication parameter.

75. A terminal, comprising: The first communication unit is used to establish a first connection and a second connection of the first session with a user plane network element, wherein the first connection is established between the terminal and the user plane network element through a first access network device, and the second connection is established between the terminal and the user plane network element through the second access network device when the terminal needs to switch from the first access network device to the second access network device; when transmitting data of the first session with the user plane network element through the second connection, the first connection is released.

76. The terminal according to claim 75, wherein, The first communication unit is configured to send uplink data of the first session to the user plane network element via the second connection when receiving downlink data of the first session from the user plane network element via the second connection.

77. The terminal according to claim 76, wherein, The first communication unit is configured to send uplink data of a first session to the user plane network element through the first connection, wherein the uplink data of the first session carries a handover indication parameter, the handover indication parameter being used to indicate a handover to the second connection for transmitting the data of the first session.

78. The terminal according to claim 75, wherein, The first communication unit is configured to send uplink data of the first session to the user plane network element via the second connection; and to receive downlink data of the first session from the user plane network element via the second connection.

79. The terminal according to claim 78, wherein, The uplink data of the first session carries a handover indication parameter, which is used to indicate a switch to the second connection to transmit the data of the first session.

80. A user plane network element, comprising: The fourth communication unit is used to establish a first connection and a second connection of the first session with the terminal, wherein the first connection is established between the terminal and the user plane network element through the first access network device, and the second connection is established between the terminal and the user plane network element through the second access network device when the terminal needs to switch from the first access network device to the second access network device; when transmitting data of the first session with the terminal through the second connection, the first connection is released.

81. The user plane network element according to claim 80, wherein, The fourth communication unit is used to send downlink data of the first session to the terminal through the second connection; and to receive uplink data of the first session from the terminal through the second connection.

82. The user plane network element according to claim 81, wherein, The fourth communication unit is configured to receive uplink data of the first session from the terminal via the first connection, wherein the uplink data of the first session carries a handover indication parameter, the handover indication parameter being used to indicate switching to the second connection to transmit the data of the first session.

83. The user plane network element according to claim 80, wherein, The fourth communication unit is configured to send downlink data of the first session to the terminal via the second connection when receiving uplink data of the first session from the terminal via the second connection.

84. The user plane network element according to claim 83, wherein, The uplink data of the first session carries a handover indication parameter, which is used to indicate a switch to the second connection to transmit the data of the first session.

85. A terminal, comprising: A transceiver, a processor, and a memory for storing a computer program, the transceiver for communicating with other devices, and the processor for calling and running the computer program stored in the memory to cause the terminal to perform the method as claimed in any one of claims 1 to 16 or 33 to 37.

86. A first core network device, comprising: A transceiver, a processor, and a memory for storing computer programs, the transceiver for communicating with other devices, and the processor for calling and running the computer programs stored in the memory to cause the first core network device to perform the method as described in any one of claims 17 to 27.

87. A second core network device, comprising: A transceiver, a processor, and a memory for storing computer programs, the transceiver for communicating with other devices, and the processor for calling and running the computer programs stored in the memory to cause the second core network device to perform the method as described in any one of claims 28 to 32.

88. A user plane network element, comprising: A transceiver, a processor, and a memory for storing a computer program, the transceiver for communicating with other devices, and the processor for calling and running the computer program stored in the memory to cause the user plane network element to perform the method as described in any one of claims 38 to 42.

89. A chip, comprising: A processor for retrieving and running a computer program from memory, causing a device having the chip mounted to perform the method as described in any one of claims 1 to 16, or claims 17 to 27, or claims 28 to 32, or claims 33 to 37, or claims 38 to 42.

90. A computer-readable storage medium for storing a computer program that, when run by a device, causes the device to perform the method as described in any one of claims 1 to 16, or claims 17 to 27, or claims 28 to 32, or claims 33 to 37, or claims 38 to 42.

91. A computer program product comprising computer program instructions that cause a computer to perform the method as described in any one of claims 1 to 16, or claims 17 to 27, or claims 28 to 32, or claims 33 to 37, or claims 38 to 42.

92. A computer program that causes a computer to perform the method as described in any one of claims 1 to 16, or claims 17 to 27, or claims 28 to 32, or claims 33 to 37, or claims 38 to 42.

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