Session management method and apparatus

Abstract

The present application relates to the technical field of communications. Provided are a session management method and apparatus. In the method, a first access network device may indicate, to a session management network element managing a first session, that an access network device manages the mobility of a terminal, or instruct the session management network element to store identification or address information of the access network device when the first session is deactivated, or instruct the session management network element to release only user plane information when the first session is deactivated. The session management network element may acquire identification or address information of a second access network device, and when the first session is deactivated, store the identification or address information of the second access network device on the basis of first information. By means of the method, when the first session is activated, the session management network element may not interact with a mobility management network element, but interact with the second access network device. Therefore, in a scenario in which the mobility management network element and the session management network element are deployed at different locations, the duration during which the session management network element activates a session can be shortened, thereby avoiding a relatively long waiting time for service data.

Description

Session management method and device

[0001] This application claims priority to Chinese Patent Application No. 202411208282.4, filed with the State Intellectual Property Office of China on August 28, 2024, entitled "Conversation Management Method and Apparatus", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to session management methods and apparatus. Background Technology

[0003] In communication systems, to enable flexible deployment of the core network, a network architecture has been introduced that allows access network devices to directly communicate with multiple network elements in the core network, such as the radio access network (RAN) interface service network architecture. In this architecture, access network devices have interfaces with core network elements such as session management network elements, user plane network elements, and mobility management network elements, enabling distributed connectivity.

[0004] Based on the network architecture described above, there may be scenarios where the session management network element and the mobility management network element are not deployed in the same location. For example, the session management network element may be deployed in the local core network, while the mobility management network element may be deployed in the central core network. This scenario increases the time required for information interaction between the session management network element and the mobility management network element. Therefore, when the session management network element activates a session, the interaction between the session management network element and the mobility management network element will result in a longer activation time, leading to longer waiting times for business data and impacting user experience. Summary of the Invention

[0005] This application provides a session management method and apparatus, which can be used in scenarios where mobility management network elements and session management network elements are deployed in different locations, thereby shortening the session activation time of the session management network element and avoiding long waiting times for business data.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] Firstly, a session management method is provided, which can be executed by a session management network element. This session management network element can refer to the network element itself, or to a processor, circuit, module, logic node, chip, or chip system within the network element that implements the method. The session management network element can manage the terminal's first session.

[0008] The method includes: receiving first information from a first access network device, obtaining the identifier or address information of a second access network device, and saving the identifier or address information of the second access network device when the first session is deactivated, based on the first information. Wherein, the first information indicates the mobility of the access network device management terminal, or the first information indicates that the identifier or address information of the access network device is saved when the first session is deactivated, or the first information indicates that only user plane information is released when the first session is deactivated, or the first information is used to establish the first session and does not carry information about mobility management network elements. The second access network device is the access network device to which the terminal accesses.

[0009] Based on the method provided in the first aspect above, the first access network device can instruct the session management network element on the mobility of the access network device management terminal, or instruct the session management network element to save the identification or address information of the access network device when the first session is deactivated, or instruct the session management network element to release only the user plane information when the first session is deactivated, or the first access network device can omit the information of the mobility management network element in the first information sent to the session management network element for establishing the first session, so that the session management network element saves the identification or address information of the second access network device when the first session is deactivated. Therefore, if the session management network element needs to activate the first session, the session management network element can interact with the second access network device without interacting with the mobility management network element, thereby shortening the session activation time of the session management network element and avoiding long waiting times for service data.

[0010] In one possible implementation, the method further includes: receiving second information from a user plane network element, the second information indicating that data from the first session has been received; and sending a first request to a second access network device based on the second information, the first request being used to request activation of the first session.

[0011] Based on the above possible implementation methods, after receiving the second information, the session management network element can directly send a first request to the second access network device to request the activation of the first session, thereby achieving rapid activation of the first session.

[0012] In one possible implementation, the method further includes: in the event that the first session activation fails, sending a second request to the mobility management network element, the second request being used to request the access network device to which the terminal is connected.

[0013] Based on the above possible implementation methods, in the event that the first session activation fails, the session management network element can request the access network device to which the terminal is connected from the mobility management network element, so as to send a session activation request to the access network device to activate the first session.

[0014] In one possible implementation, the first information indicates the mobility of the access network device management terminal; receiving the first information from the first access network device includes: receiving a first message from the first access network device, the first message including the first information, the first message being used to request the establishment of a first session.

[0015] Based on the above possible implementation methods, the first access network device can indicate the mobility of the access network device management terminal to the session management network element during the establishment of the first session, so that the session management network element can save the identification or address information of the second access network device when the first session is deactivated based on the instruction of the first access network device.

[0016] In one possible implementation, the first information instructs the first session to save the identifier or address information of the access network device when deactivating, or the first information instructs the first session to release only the user plane information when deactivating; receiving the first information from the first access network device includes: receiving a second message from the first access network device, the second message including the first information, the second message being used to request deactivation of the first session, the first access network device being the same as the second access network device.

[0017] Based on the above possible implementation methods, the first access network device may carry first information in the message requesting deactivation of the first session, to instruct that the identification or address information of the access network device be saved when the first session is deactivated, or to instruct that only the user plane information be released when the first session is deactivated, so that the session management network element can save the identification or address information of the second access network device when the first session is deactivated based on the instruction of the first access network device.

[0018] In one possible implementation, the second message is an update session management context request message.

[0019] Based on the above possible implementation methods, the first access network device can carry the first information through the update session management context request message.

[0020] In one possible implementation, the first information instructs the first session to save the identifier or address information of the access network device when deactivating, or the first information instructs the first session to release only the user plane information when deactivating; the method further includes: sending a session resource release message to the first access network device; receiving the first information from the first access network device, including: receiving a session resource release response message from the first access network device, the session resource release response message including the first information, the first access network device being the same as the second access network device.

[0021] Based on the above possible implementation methods, the first access network device can carry first information in the session resource release response message to instruct the first session to save the identification or address information of the access network device when the first session is deactivated, or to instruct the first session to release only the user plane information when the first session is deactivated, so that the session management network element can save the identification or address information of the second access network device when the first session is deactivated based on the instruction of the first access network device.

[0022] In one possible implementation, the first session is a local session. This local session can only be established within a specific area or region; or it is a session that accesses or is routed to the local core network; or it is a session that accesses or is routed to the campus network; or it is not a session that accesses or is routed to the central core network.

[0023] Based on the above possible implementation methods, the method provided in the first aspect can be executed when the first session is a local session.

[0024] Secondly, a session management method is provided, which can be executed by a session management network element. This session management network element can refer to the network element itself, or to a processor, circuit, module, logic node, chip, or chip system within the network element that implements the method. The session management network element can manage the terminal's first session.

[0025] The method includes: determining that the first session is a local session, obtaining the identifier or address information of the access network device, and saving the identifier or address information of the access network device when the first session is deactivated. Here, the access network device is the access network device to which the terminal accesses. A local session is a session that can only be established in a specific area; or a local session is a session that accesses or is routed to the local core network; or a local session is a session that accesses or is routed to the campus network; or, a local session is not a session that accesses or is routed to the central core network.

[0026] Based on the method provided in the second aspect above, the session management network element can save the identifier or address information of the access network device when the first session is deactivated, provided that the first session is determined to be a local session. Therefore, if the session management network element needs to activate the first session, it can interact with the access network device without interacting with the mobility management network element, thereby shortening the session activation time and avoiding long waiting times for service data.

[0027] In one possible implementation, the method further includes: receiving first information from a user plane network element, the first information indicating that data of a first session has been received; and sending a first request to an access network device based on the first information, the first request being used to request activation of the first session.

[0028] Based on the above possible implementation methods, after receiving the first information, the session management network element can directly send a first request to the second access network device to request the activation of the first session, thereby achieving rapid activation of the first session.

[0029] In one possible implementation, the method further includes: in the event that the first session activation fails, sending a second request to the mobility management network element, the second request being used to request the access network device to which the terminal is connected.

[0030] Based on the above possible implementation methods, in the event that the first session activation fails, the session management network element can request the access network device to which the terminal is connected from the mobility management network element, so as to send a session activation request to the access network device to activate the first session.

[0031] In one possible implementation, the session management network element stores or pre-configures at least one of the following local network information: local network slice information or local data network name information; determining that the first session is a local session includes: determining that the first session is a local session based on the local network information and the attribute information corresponding to the first session, wherein the attribute information corresponding to the first session includes at least one of slice information or data network name information.

[0032] Based on the above possible implementation methods, the session management network element can determine that the first session is a local session.

[0033] In one possible implementation, a local session is a session that can only be established in a specific area or within a particular area; or a local session is a session that accesses or is routed to the local core network; or a local session is a session that accesses or is routed to the campus network; or, a local session is not a session that accesses or is routed to the central core network.

[0034] Thirdly, a session management method is provided, which can be executed by a first access network device. Here, the first access network device can refer to the first access network device itself, or to a processor, circuit, module, logic node, chip, or chip system within the first access network device that implements the method.

[0035] The method includes: determining that the terminal's first session is a local session, and sending third information to the mobility management network element. The third information may indicate that the terminal's communication connection should be maintained, or that the terminal's communication connection should not be released, or that the terminal should not enter a connection management idle state. A local session is a session that can only be established in a specific area; or a local session is a session that accesses or is routed to the local core network; or a local session is a session that accesses or is routed to the campus network; or a local session is not a session that accesses or is routed to the central core network.

[0036] Based on the method provided in the third aspect above, when the first session is a local session, the first access network device can instruct the mobility management element to maintain the terminal's communication connection, or instruct it not to release the terminal's communication connection, or instruct the terminal not to enter the connection management idle state, so as to avoid the mobility management element releasing the terminal's communication connection. It is understood that when the mobility management element does not release the terminal's communication connection, the first access network device can manage the terminal's mobility. Therefore, if the session management element activates the first session, it can interact with the first access network device instead of the mobility management element, to quickly activate the first session, reduce the waiting time for service data, and improve the user experience.

[0037] In one possible implementation, the method further includes: sending first information to a session management network element, the first information indicating the mobility of the access network device management terminal, or the first information indicating that the identification or address information of the access network device is saved when the first session is deactivated, or the first information indicating that only the user plane information is released when the first session is deactivated, or the first information is used to establish the first session and does not carry information of the mobility management network element.

[0038] Based on the above possible implementations, the first access network device can instruct the session management network element on the mobility of the access network device management terminal, or instruct it to save the identification or address information of the access network device when deactivating the first session, or instruct it to release only the user plane information when deactivating the first session, or the first access network device can omit the information of the mobility management network element in the first information sent to the session management network element for establishing the first session, so that the session management network element saves the identification or address information of the access network device to which the terminal is connected when the first session is deactivated. Therefore, if the session management network element needs to activate the first session, it can interact with the access network device without interacting with the mobility management network element, thereby shortening the session activation time and avoiding long service data waiting times.

[0039] In one possible implementation, the first information indicates the mobility of the access network device management terminal; sending the first information to the session management network element includes: sending a first message to the session management network element, the first message including the first information, the first message being used to request the establishment of a first session.

[0040] Based on the above possible implementation methods, the first access network device can indicate the mobility of the access network device management terminal to the session management network element during the establishment of the first session, so that the session management network element can save the identification or address information of the access network device to which the terminal is connected when the first session is deactivated, based on the instruction of the first access network device.

[0041] In one possible implementation, the first information instructs the first session to save the identifier or address information of the access network device when deactivating, or the first information instructs the first session to release only the user plane information when deactivating; sending the first information to the session management network element includes: sending a second message to the session management network element, the second message including the first information, the second message being used to request the deactivation of the first session.

[0042] Based on the above possible implementation methods, the first access network device may carry first information in the message requesting deactivation of the first session, to instruct that the identification or address information of the access network device be saved when the first session is deactivated, or to instruct that only the user plane information be released when the first session is deactivated, so that the session management network element can save the identification or address information of the access network device to which the terminal is connected when the first session is deactivated based on the instruction of the first access network device.

[0043] In one possible implementation, the second message is an update session management context request message.

[0044] Based on the above possible implementation methods, the first access network device can carry the first information through the update session management context request message.

[0045] In one possible implementation, the first information instructs the first session to save the identifier or address information of the access network device when deactivating, or the first information instructs the first session to release only the user plane information when deactivating; the method further includes: receiving a session resource release message from a session management network element; sending the first information to the session management network element, including: sending a session resource release response message to the session management network element, the session resource release response message including the first information.

[0046] Based on the above possible implementation methods, the first access network device can carry first information in the session resource release response message to instruct the first session to save the identification or address information of the access network device when the first session is deactivated, or to instruct the first session to release only the user plane information when the first session is deactivated, so that the session management network element can save the identification or address information of the access network device accessed by the terminal when the first session is deactivated based on the instruction of the first access network device.

[0047] In one possible implementation, the first access network device stores or pre-configures at least one of the following local network information: local network slice information or local data network name information; determining that the first session of the terminal is a local session includes: determining that the first session is a local session based on the local network information and the attribute information corresponding to the first session, wherein the attribute information corresponding to the first session includes at least one of slice information or data network name information.

[0048] Based on the above possible implementation methods, it can be determined that the first session is a local session.

[0049] In one possible implementation, a local session is a session that can only be established in a specific area or within a particular area; or a local session is a session that accesses or is routed to the local core network; or a local session is a session that accesses or is routed to the campus network; or, a local session is not a session that accesses or is routed to the central core network.

[0050] Fourthly, a session management method is provided, which can be executed by a mobility management network element. Here, "mobility management network element" can refer to the mobility management network element itself, or to the processor, circuit, module, logic node, chip, or chip system within the mobility management network element that implements this method.

[0051] The method includes: receiving third information from a first access network device, and determining, based on the third information, not to trigger the release of the terminal's communication connection. The third information may indicate that the terminal's communication connection is maintained, or that the terminal's communication connection is not released, or that the terminal does not enter a connection management idle state.

[0052] Based on the method provided in the fourth aspect above, the first access network device can instruct the mobility management element to maintain the terminal's communication connection, or instruct it not to release the terminal's communication connection, or instruct the terminal not to enter the connection management idle state, thereby preventing the mobility management element from releasing the terminal's communication connection. It is understood that when the mobility management element does not release the terminal's communication connection, the first access network device can manage the terminal's mobility. Therefore, if the session management element activates the first session, it can interact with the first access network device instead of the mobility management element to quickly activate the first session, reduce the waiting time for service data, and improve the user experience.

[0053] In one possible implementation, determining whether to trigger the release of the terminal's communication connection based on third information includes: if a local network slice exists in the network slice information allowed by the terminal, determining whether to trigger the release of the terminal's communication connection based on the third information.

[0054] Based on the above possible implementation methods, when there is no local network slice in the network slice information allowed by the terminal, the mobility management element can choose to release the terminal's communication connection, so that the mobility management element in the core network can reasonably control the communication connection status of the terminal.

[0055] Fifthly, a session management method is provided, which can be executed by a session management network element. Here, the session management network element can refer to the session management network element itself, or to the processor, circuit, module, logic node, chip, or chip system within the session management network element that implements the method. The session management network element can manage the terminal's first session.

[0056] The method includes: sending first information to a first access network device, obtaining the identifier or address information of a second access network device, and saving the identifier or address information of the second access network device when the first session is deactivated. The first information is used to indicate the mobility of the access network device management terminal, or the first information is used to request the mobility of the access network device management terminal. The second access network device is the access network device to which the terminal accesses.

[0057] Based on the method provided in the fifth aspect above, the session management network element can indicate / request the mobility of the access network device management terminal to the first access network device, so that the session management network element can save the information of the access network device to which the terminal is connected when the first session is deactivated. Therefore, when activating the first session, the session management network element can interact with the access network device instead of interacting with the mobility management network element, thereby quickly activating the first session.

[0058] In one possible implementation, the method further includes: receiving second information from a user plane network element, the second information indicating that data from the first session has been received; and sending a first request to a second access network device based on the second information, the first request being used to request activation of the first session.

[0059] Based on the above possible implementation methods, after receiving the second information, the session management network element can directly send a first request to the second access network device to request the activation of the first session, thereby achieving rapid activation of the first session.

[0060] In one possible implementation, the method further includes: in the event that the first session activation fails, sending a second request to the mobility management network element, the second request being used to request the access network device to which the terminal is connected.

[0061] Based on the above possible implementation methods, in the event that the first session activation fails, the session management network element can request the access network device to which the terminal is connected from the mobility management network element, so as to send a session activation request to the access network device to activate the first session.

[0062] In one possible implementation, the method further includes: receiving third information from a first access network device, the third information being used to confirm the mobility of the access network device management terminal; and saving the identifier or address information of a second access network device when the first session is deactivated, including: saving the identifier or address information of the second access network device when the first session is deactivated based on the third information.

[0063] Based on the above possible implementation methods, after the first access network device confirms the mobility of the management terminal, the session management network element can save the identifier or address information of the second access network device when the first session is deactivated, so as to exchange information with the second access network device when activating the first session and realize the rapid activation of the first session.

[0064] In one possible implementation, the method further includes: receiving first policy information, the first policy information instructing the first session to maintain control plane connection in a deactivated state; and sending first information to the first access network device, including: sending the first information to the first access network device according to the first policy information.

[0065] Based on the above possible implementation methods, the session management network element can send first information to the first access network device according to the first policy information to indicate or request the mobility of the access network device management terminal.

[0066] In one possible implementation, sending first information to the first access network device includes: sending first information to the first access network device when the first session is a local session. The local session is a session that can only be established in a specific area or within a particular region; or the local session is a session that accesses or is routed to the local core network; or the local session is a session that accesses or is routed to the campus network; or the local session is not a session that accesses or is routed to the central core network.

[0067] Based on the above possible implementation methods, the session management network element can send first information to the first access network device when the first session is a local session, in order to indicate or request the mobility of the access network device management terminal.

[0068] Sixthly, a session management method is provided, which can be executed by a first access network device. Here, the first access network device can refer to the first access network device itself, or to a processor, circuit, module, logic node, chip, or chip system within the first access network device that implements the method.

[0069] The method includes: receiving first information from a session management network element, and determining, based on the first information, whether the terminal will not enter a connection management idle state, or whether the terminal can enter a radio resource control inactive state. The first information is used to indicate the mobility of the access network device management terminal, or to request the mobility of the access network device management terminal.

[0070] Based on the method provided in the sixth aspect above, the first access network device can determine, according to the instruction or request of the session management network element, whether the terminal should not enter the connection management idle state or whether the terminal can enter the radio resource control inactive state. That is, the mobility of the terminal is managed by the first access network device, so when the session management network element activates the first session, it can interact with the first access network device instead of the mobility management network element, thereby quickly activating the first session.

[0071] In one possible implementation, the method further includes: sending the identifier or address information of the second access network device to the session management network element when the terminal switches to the second access network device.

[0072] Based on the above possible implementation methods, when activating the first session, the session management network element can interact with the second access network device to quickly activate the first session.

[0073] In one possible implementation, the first session of the session management network element management terminal is a local session. This local session can only be established within a specific area; or it is a session that accesses or is routed to the local core network; or it is a session that accesses or is routed to the campus network; or it is not a session that accesses or is routed to the central core network.

[0074] In a seventh aspect, a communication apparatus is provided for implementing the method provided in the first aspect. The communication apparatus can be a session management network element as described in the first aspect. The communication apparatus includes modules, units, or means corresponding to the method described above. These modules, units, or means can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the functions described above.

[0075] In one possible implementation, the communication device may include a processing module and an interface module. The processing module can be used to implement the processing functions described in the first aspect and any possible implementation thereof. The processing module may be, for example, a processor. The interface module, also referred to as an interface unit, is used to implement the sending and / or receiving functions described in the first aspect and any possible implementation thereof. The interface module may consist of an interface circuit, a transceiver, a transceiver unit, or a communication interface.

[0076] In one possible implementation, the interface module is configured to receive first information from a first access network device, the first information instructing the access network device to manage the mobility of the terminal, or the first information instructing the first session to save the identifier or address information of the access network device when deactivating, or the first information instructing the first session to release only user plane information when deactivating, or the first information is used to establish the first session and does not carry information about mobility management network elements; the processing module is configured to obtain the identifier or address information of a second access network device, the second access network device being the access network device to which the terminal accesses; the processing module is further configured to save the identifier or address information of the second access network device when deactivating the first session according to the first information.

[0077] In one possible implementation, the interface module is further configured to receive second information from the user plane network element, the second information indicating that data of the first session has been received; the interface module is further configured to send a first request to the second access network device based on the second information, the first request being used to request activation of the first session.

[0078] In one possible implementation, the interface module is further configured to send a second request to the mobility management network element in the event that the first session activation fails. The second request is used to request the access network device to which the terminal is connected.

[0079] In one possible implementation, the first information instructs the access network device to manage the mobility of the terminal; the interface module is specifically configured to receive a first message from the first access network device, the first message including the first information, the first message being used to request the establishment of the first session.

[0080] In one possible implementation, the first information instructs the first session to save the identifier or address information of the access network device when deactivating, or the first information instructs the first session to release only the user plane information when deactivating; the interface module is specifically used to receive a second message from the first access network device, the second message including the first information, the second message being used to request deactivation of the first session, the first access network device being the same as the second access network device.

[0081] In one possible implementation, the second message is an update session management context request message.

[0082] In one possible implementation, the first information instructs the first session to save the identifier or address information of the access network device when deactivating, or the first information instructs the first session to release only the user plane information when deactivating; the interface module is further configured to send a session resource release message to the first access network device; the interface module is specifically configured to receive a session resource release response message from the first access network device, the session resource release response message including the first information, and the first access network device is the same as the second access network device.

[0083] In one possible implementation, the first session is a local session. This local session can only be established within a specific area or region; or it is a session that accesses or is routed to the local core network; or it is a session that accesses or is routed to the campus network; or it is not a session that accesses or is routed to the central core network.

[0084] Eighthly, a communication apparatus is provided for implementing the method provided in the second aspect. The communication apparatus can be a session management network element as described in the second aspect. The communication apparatus includes modules, units, or means that implement the method described above. These modules, units, or means can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the functions described above.

[0085] In one possible implementation, the communication device may include a processing module and an interface module. The processing module can be used to implement the processing functions in the second aspect described above and any possible implementation thereof. The processing module may be, for example, a processor. The interface module, also referred to as an interface unit, is used to implement the sending and / or receiving functions in the second aspect described above and any possible implementation thereof. The interface module may consist of an interface circuit, a transceiver, a transceiver unit, or a communication interface.

[0086] In one possible implementation, the processing module is used to determine that the first session is a local session, which is a session accessing or routed to the local core network; the processing module is also used to obtain the identifier or address information of the access network device; the processing module is also used to save the identifier or address information of the access network device when the first session is deactivated. Here, the aforementioned access network device is the access network device accessed by the terminal. A local session is a session that can only be established in a specific area; or, a local session is a session accessing or routed to the local core network; or, a local session is a session accessing or routed to the campus network; or, a local session is not a session accessing or routed to the central core network.

[0087] In one possible implementation, the interface module is further configured to receive first information from a user plane network element, the first information indicating that data of the first session has been received; the interface module is further configured to send a first request to the access network device based on the first information, the first request being used to request activation of the first session.

[0088] In one possible implementation, the interface module is further configured to send a second request to the mobility management network element in the event that the first session activation fails. The second request is used to request the access network device to which the terminal is connected.

[0089] In one possible implementation, the session management network element stores or pre-configures at least one of the following local network information: local network slice information or local data network name information; the processing module is specifically used to determine that the first session is a local session based on the local network information and the attribute information corresponding to the first session, wherein the attribute information corresponding to the first session includes at least one of slice information or data network name information.

[0090] Ninthly, a communication apparatus is provided for implementing the method provided in the third aspect. The communication apparatus can be the first access network device in the third aspect. The communication apparatus includes modules, units, or means corresponding to the above-described method, which can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the above-described functions.

[0091] In one possible implementation, the communication device may include a processing module and an interface module. The processing module can be used to implement the processing functions in the third aspect described above and any possible implementation thereof. The processing module may be, for example, a processor. The interface module, also referred to as an interface unit, is used to implement the sending and / or receiving functions in the third aspect described above and any possible implementation thereof. The interface module may consist of an interface circuit, a transceiver, a transceiver unit, or a communication interface.

[0092] In one possible implementation, a processing module is used to determine that the terminal's first session is a local session. This local session is either a session that can only be established in a specific area or within a particular area; or a local session that accesses or is routed to the local core network; or a local session that accesses or is routed to the campus network; or a local session that does not access or is routed to the central core network. An interface module is used to send third information to the mobility management network element, which indicates that the terminal's communication connection should be maintained, or that the terminal's communication connection should not be released, or that the terminal should not enter a connection management idle state.

[0093] In one possible implementation, the interface module is further configured to send first information to the session management network element, the first information instructing the access network device to manage the mobility of the terminal, or the first information instructing the access network device to save its identifier or address information when the first session is deactivated, or the first information instructing the user plane information to be released only when the first session is deactivated, or the first information is used to establish the first session and does not carry information about the mobility management network element.

[0094] In one possible implementation, the first information instructs the access network device to manage the mobility of the terminal; the interface module is specifically used to send a first message to the session management network element, the first message including the first information, the first message being used to request the establishment of the first session.

[0095] In one possible implementation, the first information instructs the first session to save the identifier or address information of the access network device when deactivating, or the first information instructs the first session to release only the user plane information when deactivating; the interface module is specifically used to send a second message to the session management network element, the second message including the first information, the second message being used to request deactivation of the first session.

[0096] In one possible implementation, the second message is an update session management context request message.

[0097] In one possible implementation, the first information instructs the first session to save the identifier or address information of the access network device when the first session is deactivated, or the first information instructs the first session to release only the user plane information when the first session is deactivated; the interface module is further configured to receive a session resource release message from the session management network element; the interface module is specifically configured to send a session resource release response message to the session management network element, the session resource release response message including the first information.

[0098] In one possible implementation, the first access network device stores or pre-configures at least one of the following local network information: local network slice information or local data network name information; the processing module is specifically used to determine that the first session is a local session based on the local network information and the attribute information corresponding to the first session, wherein the attribute information corresponding to the first session includes at least one of slice information or data network name information.

[0099] In a tenth aspect, a communication apparatus is provided for implementing the method provided in the fourth aspect above. The communication apparatus can be a mobility management network element as described in the fourth aspect. The communication apparatus includes modules, units, or means that implement the method described above. These modules, units, or means can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the functions described above.

[0100] In one possible implementation, the communication device may include a processing module and an interface module. The processing module can be used to implement the processing functions in the fourth aspect described above and any possible implementation thereof. The processing module may be, for example, a processor. The interface module, also referred to as an interface unit, is used to implement the sending and / or receiving functions in the fourth aspect described above and any possible implementation thereof. The interface module may consist of an interface circuit, a transceiver, a transceiver unit, or a communication interface.

[0101] In one possible implementation, the interface module is configured to receive third information from the first access network device, the third information indicating that the terminal's communication connection should be maintained, or the third information indicating that the terminal's communication connection should not be released, or the third information indicating that the terminal should not enter the connection management idle state; the processing module is configured to determine, based on the third information, not to trigger the release of the terminal's communication connection.

[0102] In one possible implementation, the processing module is specifically configured to determine, based on the third information, not to trigger the release of the terminal's communication connection if a local network slice exists in the allowed network slice information of the terminal.

[0103] Eleventhly, a communication device is provided for implementing the method provided in the fifth aspect above. The communication device can be a session management network element as described in the fifth aspect. The communication device includes modules, units, or means corresponding to the above method, which can be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the above functions.

[0104] In one possible implementation, the communication device may include a processing module and an interface module. The processing module can be used to implement the processing functions in the fifth aspect described above and any possible implementation thereof. The processing module may be, for example, a processor. The interface module, also referred to as an interface unit, is used to implement the sending and / or receiving functions in the fifth aspect described above and any possible implementation thereof. The interface module may consist of an interface circuit, a transceiver, a transceiver unit, or a communication interface.

[0105] In one possible implementation, the interface module is configured to send first information to a first access network device, the first information being used to instruct the access network device to manage the mobility of the terminal, or the first information being used to request the access network device to manage the mobility of the terminal; the processing module is configured to obtain the identifier or address information of a second access network device, the second access network device being the access network device to which the terminal is connected; the processing module is further configured to save the identifier or address information of the second access network device, the second access network device being the access network device to which the terminal is connected, when the first session is deactivated.

[0106] In one possible implementation, the interface module is further configured to receive second information from the user plane network element, the second information indicating that data of the first session has been received; the interface module is further configured to send a first request to the second access network device based on the second information, the first request being used to request activation of the first session.

[0107] In one possible implementation, the interface module is further configured to send a second request to the mobility management network element in the event that the first session activation fails. The second request is used to request the access network device to which the terminal is connected.

[0108] In one possible implementation, the interface module is further configured to receive third information from the first access network device, the third information being used to confirm that the access network device manages the mobility of the terminal; the processing module is specifically configured to save the identifier or address information of the second access network device when the first session is deactivated based on the third information.

[0109] In one possible implementation, the interface module is further configured to receive first policy information, which instructs the first session to maintain control plane connection in the deactivated state; specifically, the interface module is configured to send the first information to the first access network device according to the first policy information.

[0110] In one possible implementation, the interface module is specifically used to send the first information to the first access network device when the first session is a local session; wherein the local session is a session that can only be established in a specific area or within a specific area; or the local session is a session that accesses or is routed to the local core network; or the local session is a session that accesses or is routed to the campus network; or the local session is not a session that accesses or is routed to the central core network.

[0111] In a twelfth aspect, a communication apparatus is provided for implementing the method provided in the sixth aspect. The communication apparatus may be the first access network device described in the sixth aspect. The communication apparatus includes modules, units, or means corresponding to the above-described method, which may be implemented in hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units corresponding to the above-described functions.

[0112] In one possible implementation, the communication device may include a processing module and an interface module. The processing module can be used to implement the processing functions in the sixth aspect and any possible implementation thereof. The processing module may be, for example, a processor. The interface module, also referred to as an interface unit, is used to implement the sending and / or receiving functions in the sixth aspect and any possible implementation thereof. The interface module may consist of an interface circuit, a transceiver, a transceiver unit, or a communication interface.

[0113] In one possible implementation, the interface module is configured to receive first information from the session management network element, the first information being used to indicate the mobility of the access network device management terminal, or the first information being used to request the mobility of the access network device management terminal; the processing module is configured to determine, based on the first information, that the terminal does not enter the connection management idle state, or determine that the terminal can enter the radio resource control inactive state.

[0114] In one possible implementation, the interface module is further configured to send the identifier or address information of the second access network device to the session management network element when the terminal switches to the second access network device.

[0115] In one possible implementation, the session management network element manages the terminal's first session, which is a local session that can only be established in a specific area or within a particular region; or the local session is a session that accesses or is routed to the local core network; or the local session is a session that accesses or is routed to the campus network; or the local session is not a session that accesses or is routed to the central core network.

[0116] In a thirteenth aspect, a communication device is provided, comprising: a processor; configured to cause the communication device to perform the method described in any of the preceding aspects by executing a computer program (or computer-executable instructions) stored in a memory, and / or by means of logic circuitry. The communication device may be a session management network element as described in the first, second, or fifth aspects; or, the communication device may be a first access network device as described in the third or sixth aspects; or, the communication device may be a mobility management network element as described in the fourth aspect. Optionally, the number of processors may be one or more.

[0117] In one possible implementation, the communication device also includes a memory.

[0118] In one possible implementation, the processor and memory are integrated together; or, the memory is independent of the processor.

[0119] In one possible implementation, the communication device further includes a communication interface for communicating with other devices, such as transmitting or receiving data and / or signals. Exemplarily, the communication interface may be a transceiver, circuit, bus, module, or other type of communication interface.

[0120] In one possible implementation, the processor and / or memory also include an artificial intelligence (AI) module for implementing AI-related functions. The AI ​​module can implement AI functions through software, hardware, or a combination of both. For example, the AI ​​module may include a radio access network (RAN) intelligent controller (RIC) module. The AI ​​module could be a near real-time RIC or a non-real-time RIC.

[0121] In one possible implementation, the communication device is a chip or a chip system. Optionally, when the communication device is a chip system, it can be composed of chips or may include chips and other discrete components.

[0122] In a fourteenth aspect, a communication device is provided, comprising: a processor and an interface circuit; the interface circuit being configured to receive a computer program or instructions and transmit them to the processor; the processor being configured to execute the computer program or instructions to cause the communication device to perform the method described in any of the preceding aspects. The communication device may be a session management network element as described in the first, second, or fifth aspects; or, the communication device may be a first access network device as described in the third or sixth aspects; or, the communication device may be a mobility management network element as described in the fourth aspect. Optionally, the number of processors may be one or more.

[0123] In one possible implementation, the processor also includes an AI module for implementing AI-related functions. The AI ​​module can implement AI functions through software, hardware, or a combination of both. For example, the AI ​​module may include a RIC module. The AI ​​module could be a near real-time RIC or a non-real-time RIC.

[0124] In one possible implementation, the communication device is a chip or a chip system. Optionally, when the communication device is a chip system, it can be composed of chips or may include chips and other discrete components.

[0125] In a fifteenth aspect, a computer-readable storage medium is provided that stores instructions which, when executed on a computer, enable the computer to perform the methods described in any of the preceding aspects.

[0126] In a sixteenth aspect, a computer program product containing instructions is provided that, when run on a computer, enables the computer to perform the methods described in any of the preceding aspects.

[0127] In a seventeenth aspect, a communication system is provided, comprising at least one of the following: a session management network element for performing the method described in the first aspect, a first access network device for performing the method described in the third aspect, or a mobility management network element for performing the method described in the fourth aspect.

[0128] In an eighteenth aspect, a communication system is provided, comprising at least one of the following: a session management network element for performing the method described in the second aspect, a first access network device for performing the method described in the third aspect, or a mobility management network element for performing the method described in the fourth aspect.

[0129] In a nineteenth aspect, a communication system is provided, comprising at least one of the following: a session management network element for performing the method described in the fifth aspect above, or a first access network device for performing the method described in the sixth aspect above.

[0130] The technical effects of any possible implementation of aspects seven through nineteen can be found in the technical effects of any one of aspects one through six above, or different possible implementations of any one of aspects, and will not be repeated here.

[0131] Understandably, provided that the solutions do not contradict each other, the solutions in the above aspects can be combined. Attached Figure Description

[0132] Figure 1 is a schematic diagram of the communication system architecture provided in this application;

[0133] Figure 2 is a schematic diagram of the RAN interface service-oriented network architecture provided in this application;

[0134] Figure 3 is a schematic diagram of the structure of access network equipment in an open RAN (O-RAN or ORAN) system;

[0135] Figure 4 is a schematic diagram of the hardware structure of the communication device provided in this application;

[0136] Figure 5 is a flowchart illustrating the session management method provided in this application.

[0137] Figure 6A is a flowchart of the session management method provided in this application (II).

[0138] Figure 6B is a flowchart illustrating the session management method provided in this application.

[0139] Figure 7 is a flowchart illustrating the session management method provided in this application.

[0140] Figure 8 is a flowchart illustrating the session management method provided in this application.

[0141] Figure 9 is a flowchart illustrating the session management method provided in this application.

[0142] Figure 10 is a flowchart illustrating the session management method provided in this application.

[0143] Figure 11 is a schematic diagram of the communication device provided in this application. Detailed Implementation

[0144] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0145] The method provided in this application can be used in various communication systems. For example, the communication system can be a long-term evolution (LTE) system, a 5th generation (5G) communication system, a wireless fidelity (WiFi) system, a 3rd generation partnership project (3GPP) related communication system, a communication system evolving after 5G, or a system integrating multiple systems, etc., without limitation. 5G can also be referred to as new radio (NR). The method provided in this application is described below using the communication system 1000 shown in Figure 1 as an example. Figure 1 is only a schematic diagram and does not constitute a limitation on the applicable scenarios of the technical solution provided in this application.

[0146] Figure 1 shows a schematic diagram of the architecture of the communication system 1000 provided in this application. In Figure 1, the communication system 1000 may include a session management network element 101 and an access network device 102 communicatively connected to the session management network element 101. Optionally, the communication system 1000 may also include at least one of a mobility management network element 103, a terminal 104, a user plane network element 105, or an access network device 108.

[0147] In Figure 1, the session management network element 101 and the mobility management network element 103 are deployed in different locations, such as in different core networks. For example, session management network element 101 is deployed in core network 107, and mobility management network element 103 is deployed in core network 106. Core network 106 is different from core network 107. For example, core network 106 is a central core network, while core network 107 is a local core network. The area associated with the central core network is larger than the area associated with the local core network. For example, a central core network refers to a core network deployed for multiple administrative regions, one or more cities, or one province, while a local core network refers to a core network deployed for a specific region or area. A specific region or area may be, for example, an administrative region or a park (such as an enterprise park).

[0148] The session management network element 101 is a network element in the core network 107, which can manage the sessions of terminals (such as terminal 104). For example, the session management network element 101 can establish sessions for terminals, deactivate existing sessions, or activate sessions that are in a deactivated state. In this application, the session management network element can also be called a session control and management network element, or a session control network element, etc.

[0149] In Figure 1, the access network device (such as access network device 102 or access network device 108) is a device in the access network that can manage the mobility of a terminal (such as terminal 104) that establishes a session in the core network 107. The mobility anchor point of this session is at the access network device. The terminal does not enter the connection management (CM) idle state, or the access network device can release the air interface connection with the terminal. However, for the terminal, the access network device maintains the communication connection with network elements in the core network (such as session management network elements, mobility management network elements, etc.). That is, the access network device supports the terminal entering the radio resource control (RRC) inactive state, but the terminal does not enter the RRC idle state. Access network equipment includes, but is not limited to: evolved Node Bs (NodeBs, eNBs, or e-NodeBs) in LTE, next-generation eNBs (ng-eNBs) in next-generation LTE, base stations (gNodeBs or gNBs) in NR, transmitting points (TPs) or transmission receiving points / transmission reception points (TRPs), base stations evolved by 3GPP, base stations in future mobile communication systems, satellites, access points (APs) in WiFi systems, wireless relay nodes, wireless backhaul nodes, integrated access and backhaul (IAB) nodes, and network equipment in mobile switching center non-terrestrial network (NTN) communication systems. These can be deployed on low-altitude platforms, high-altitude platforms, or satellites. Base stations can be: macro base stations, micro base stations, pico base stations, small cells, relay stations, or balloon stations, etc. Multiple base stations can support networks using the same technology mentioned above, or they can support networks using different technologies mentioned above. A base station can contain one or more co-located or non-co-located TRPs. Access network equipment can also function as a base station in device-to-device (D2D) communication, vehicular communication, drone communication, and machine communication. Access network equipment can also be a radio controller in a cloud radio access network (CRAN) scenario.Access network equipment can also be a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), a radio unit (RU), an RSU with base station functionality, a wired access gateway, or a core network element, etc. Access network equipment can also be a server, wearable device, machine-to-machine communication device, or vehicle-mounted device, etc. The following explanation uses a base station as an example. The multiple RAN nodes can be base stations of the same type or different types. A base station can communicate with a terminal, or it can communicate with a terminal through a relay station. A terminal can communicate with multiple base stations using different technologies; for example, a terminal can communicate with a base station supporting LTE networks, or it can communicate with a base station supporting 5G networks, and it can also support dual connectivity with both LTE and 5G network base stations.

[0150] The CU (Core Unit) can implement the functions of the RRC (Redirect Recognition Control) layer and the Packet Data Convergence Protocol (PDCP) layer in the 3GPP standard. The CU can also implement the functions of the Service Data Adaptation Protocol (SDAP) layer. The DU (Distributed Unit) can implement the functions of the radio link control (RLC) layer and the medium access control (MAC) layer in the 3GPP standard. The DU can also implement some or all physical layer functions, such as forward error correction (FEC) encoding / decoding, scrambling / descrambling, or modulation / demodulation. The RU (Radio Reception Unit) can be used to implement radio frequency signal transmission and reception functions. The CU and DU can be set up separately or included in the same network element, such as in the baseband unit (BBU). It is understood that the CU can be classified as a network device in the access network or a network device in the core network; this is not limited here. Furthermore, the CU can be further divided into CU-CP and CU-UP. The CU-CP can implement the functions of the RRC layer and the control plane functions of the PDCP layer. CU-UP can implement the functions of the SDAP layer and the user plane functions of the PDCP layer.

[0151] RUs can be included in radio frequency (RF) equipment or RF units, such as remote radio units (RRUs), active antenna units (AAUs), or remote radio heads (RRHs). RUs can implement some physical layer functions and RF functions as defined in the 3GPP standard. The physical layer functions that RUs can implement include one or more of the following: Fast Fourier Transform (FFT), Inverse Fast Fourier Transform (IFFT), digital beamforming, or extraction and filtering of the Physical Random Access Channel (PRACH).

[0152] Any of the CU (or CU-CP, CU-UP), DU, and RU units in this application can be implemented through software modules, hardware modules, or a combination of software and hardware modules. Furthermore, the access network equipment in this application can also be referred to as an access network node, RAN node, access node, etc.

[0153] Mobility management network element 103 is a network element in core network 106, capable of managing the mobility of terminals establishing sessions in core network 106. The mobility anchor point of this session is in mobility management network element 103. The terminal can enter CM idle state, RRC inactive state, or RRC idle state. The mobility management network element in this application can also be referred to as access management network element, access control and management network element, access registration network element, or registration function network element, etc.

[0154] Terminal 104 is a device with wireless transceiver capabilities that can be deployed on land, including indoors, outdoors, handheld, or vehicle-mounted; it can also be deployed on water (such as on ships); and it can be deployed in the air (such as on airplanes, balloons, and satellites). The terminal in this application can also be referred to as a terminal device, which can be user equipment (UE), mobile station (MS), mobile terminal (MT), or any device used to provide voice or data connectivity to a user. UE includes handheld devices with wireless communication capabilities, vehicle-mounted devices (e.g., cars, bicycles, electric vehicles, airplanes, ships, trains, high-speed trains, etc.), wearable devices (e.g., smartwatches, smart bracelets, pedometers, glasses, etc.), or computing devices. For example, a UE can be a mobile phone, tablet computer, laptop computer, PDA, mobile internet device (MID), satellite terminal, or computer with wireless transceiver capabilities. UE can also be a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless modem, a point-of-sale (POS) machine, customer-premises equipment (CPE), a smart robot, a robotic arm, workshop equipment, smart home devices (e.g., refrigerators, televisions, air conditioners, electricity meters, etc.), a wireless terminal in industrial control, a wireless terminal in autonomous driving, a wireless terminal in telemedicine, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in intelligent transportation, a wireless terminal in a smart city, a wireless terminal in a smart home, an in-vehicle terminal, a roadside unit (RSU) with terminal functionality, or a flying device (e.g., a smart robot, a hot air balloon, a drone, an airplane), etc. A terminal can also be other devices with terminal functionality; for example, a terminal can also be a device that performs terminal functionality in D2D communication.

[0155] Understandably, in some scenarios, the roles of access network devices and terminals are relative. For example, a helicopter or drone, which is usually configured as a terminal, can also be configured as a mobile base station, and the device that accesses the RAN via the helicopter or drone is configured as a terminal.

[0156] User plane network element 105 is a network element in the core network (such as core network 107). It can forward the data sent by terminal 104 to the data network (DN) to the DN, and forward the data sent by the DN to terminal 104 to the access network device, so that the access network device can forward the data to terminal 104.

[0157] It is understood that the above-mentioned communication system 1000 can be applied to a variety of communication networks, such as RAN interface service networks, or other future networks, etc. This application does not make any specific limitations in this regard.

[0158] For example, the communication system 1000 is applicable to the RAN interface service network shown in Figure 2. The network shown in Figure 2 includes terminals, access network (AN) / RAN (abbreviated as (R)AN), session management function (SMF) network elements, access and mobility management function (AMF) network elements, policy control function (PCF) network elements, selection function network elements, identity storage function network elements, unified data management (UDM) network elements, user plane function (UPF) network elements, and DN.

[0159] In Figure 2, the terminal can access the network via (R)AN. The (R)AN (such as the access network equipment within the (R)AN) has communication interfaces with UPF, SMF, AMF, PCF, or optional function network elements, allowing for direct communication. Furthermore, the communication connections between the SMF, AMF, PCF, optional function, identifier storage function, or UDM network elements shown in Figure 2 can utilize service-oriented interfaces for interaction.

[0160] In Figure 2, the terminal, (R)AN, UPF network element, and DN are generally referred to as data plane network functions and entities. Data sent by the terminal can reach the DN via the (R)AN and UPF network elements, and data sent by the DN can reach the terminal via the UPF network element and (R)AN. The network elements in Figure 2 other than the terminal, (R)AN, UPF network element, and DN are generally referred to as control plane network functions and entities, which are responsible for functions such as authentication, authorization, registration management, session management, mobility management, and policy control, thereby achieving reliable and stable transmission of user-layer traffic (such as data sent by the terminal or data sent by the DN). The user plane can be used to carry service data, and the control plane can be used to carry signaling messages.

[0161] The functions of each device or network element in Figure 2 are described below.

[0162] Deploying access network equipment in (R)AN can provide wireless access services to terminals. For example, access network equipment can be responsible for one or more functions such as radio resource management, quality of service management, data compression or data encryption on the air interface side.

[0163] AMF (Automatic Facilitation Module) network elements are core network elements, primarily responsible for signaling processing, such as access control, mobility management, attach and detach, and gateway selection. When an AMF network element provides services for a terminal's session, it can provide control plane storage resources for that session to store the session identifier and the identifier of the SMF network element associated with the session identifier.

[0164] SMF network elements can be responsible for user plane network element selection, user plane network element redirection, Internet Protocol (IP) address allocation, bearer establishment, modification and release, and quality of service (QoS) control.

[0165] UPF network elements can be responsible for forwarding and receiving user data in terminals. For example, a UPF network element can receive user data from the DN and send it to the terminal through the access network equipment; a UPF network element can also receive user data from the terminal through the access network equipment and forward it to the DN. The transmission resources and scheduling functions provided by the UPF network element to the terminal are managed and controlled by the SMF network element.

[0166] PCF network elements can be responsible for policy control decisions, provide policy rules for control plane functions, and traffic-based billing control functions, etc.

[0167] The selection function network element can be used to select a core network element for a terminal. For example, a core network element in the network can register with the selection function network element, and then the selection function network element can select a target core network element for the terminal from the registered core network elements. As another example, the selection function network element can obtain the terminal's subscription data from a UDM network element, and then select a target core network element for the terminal based on the core network element registration information and the terminal's subscription data. For instance, the selection function network element can be a network repository function (NRF) network element.

[0168] The identifier storage function network element can be used to store the mapping relationship between temporary and permanent identifiers of terminals. Specifically, network elements with registration functions, such as the AMF network element, can store this mapping relationship in the identifier storage function network element after obtaining it. For example, the identifier storage function network element can be a unified data repository (UDR) network element.

[0169] UDM network elements are primarily responsible for the management of terminal subscription data, including the storage and management of terminal identifiers and terminal access authorization.

[0170] Understandably, the device or entity corresponding to Session Management Network Element 101 in Communication System 1000 is the SMF network element in the network shown in Figure 2. The device or entity corresponding to Access Network Device 102 or Access Network Device 108 in Communication System 1000 is the Access Network Device deployed in the (R)AN in the network shown in Figure 2. The device or entity corresponding to Mobility Management Network Element 103 in Communication System 1000 is the AMF network element in the network shown in Figure 2. The device or entity corresponding to Terminal 104 in Communication System 1000 is the Terminal in the network shown in Figure 2. The device or entity corresponding to User Plane Network Element 105 in Communication System 1000 is the UPF network element in the network shown in Figure 2.

[0171] It is understood that the network architecture shown in Figure 2 is only an example of the RAN interface service network architecture. In specific applications, the RAN interface service network architecture can also take other forms. For example, it can include more or fewer network elements than the network architecture shown in Figure 2, or the network elements in Figure 2 can be replaced with other network elements or devices with similar functions, without limitation.

[0172] In some embodiments, the access network device in this application may be an access network device in an O-RAN system. O-RAN aims to achieve an intelligent and open access network. The main feature of the O-RAN architecture is the separation of hardware and software, realizing the virtualization of network functions and the standardization of hardware. In addition, O-RAN also introduces artificial intelligence (AI). In the O-RAN system, CU can also be called O-CU (Open CU), DU can also be called O-DU, CU-CP can also be called O-CU-CP, CU-UP can also be called O-CU-UP, and RU can also be called O-RU.

[0173] For example, in an O-RAN system, the access network equipment can have the structure shown in Figure 3. In Figure 3, the access network equipment includes a service management and orchestration framework (SMO) module, a near-real-time RAN intelligent controller (Near-RT RIC or nRT RIC), O-CU-CP, O-CU-UP, O-DU, and O-RU. Each module will be described in detail below.

[0174] The SMO module is a subsystem for operation administration and maintenance (OAM) network management and non-real-time radio resource control. The SMO module may include a non-real-time RAN intelligent controller (Non-RT RIC or NRT RIC). The Non-RT RIC enables non-real-time intelligent management of RAN functions. For example, a Non-RT RIC can implement AI / machine learning (ML) workflows including model training and updates, and guide applications or functions within the Near-RT RIC based on policies.

[0175] Near-RT RIC enables near real-time intelligent management of the RAN. For example, Near-RT RIC can achieve near real-time control and optimization of O-RAN modules and resources through data collection and related operations on the E2 interface.

[0176] The functions of O-CU-CP and O-RU are similar, as described in the previous section on CU-CP. The functions of O-CU-UP and O-DU are similar, as described in the previous section on CU-UP. The functions of O-RU and O-RU are similar, as described in the previous section on RU.

[0177] In addition, the Non-RT RIC and Near-RT RIC can communicate via the A1 interface. The Near-RT RIC can communicate with the O-CU-CP, O-CU-UP, and O-DU via the E2 interface. The O-CU-CP and O-DU can communicate via the F1-c interface. The O-CU-UP and O-DU can communicate via the F1-u interface. The SMO module can communicate with the Near-RT RIC, O-CU-CP, O-CU-UP, and O-DU via the O1 interface. Optionally, the SMO module can also communicate with the O-RU via the O1 interface.

[0178] It is understood that the communication system 1000 shown in Figure 1 is for illustrative purposes only and is not intended to limit the technical solutions of this application. Those skilled in the art should understand that in specific implementations, the communication system 1000 may also include other devices, and the number of session management network elements, access network devices, mobility management network elements, terminals, or user plane network elements can be determined according to specific needs without limitation.

[0179] Optionally, each network element or device in Figure 1 of this application (such as session management network element, access network device or mobility management network element, etc.) may also be referred to as a communication device, which may be a general-purpose device or a special-purpose device. This application does not make any specific limitation on this.

[0180] Optionally, the functions of each network element or device (e.g., session management network element, access network device, or mobility management network element) in Figure 1 of this application can be implemented by one device, multiple devices working together, or one or more functional modules within a single device. This application does not impose specific limitations on these functions. It is understood that the aforementioned functions can be network elements in hardware devices, software functions running on dedicated hardware, a combination of hardware and software, or virtualization functions instantiated on a platform (e.g., a cloud platform).

[0181] In practical implementation, each network element or device in Figure 1 of this application (e.g., session management network element, access network device, or mobility management network element, etc.) can adopt the composition structure shown in Figure 4, or include the components shown in Figure 4. Figure 4 shows a schematic diagram of the hardware structure of a communication device applicable to this application. It is understood that the communication device 40 includes means of necessary forms such as modules, units, elements, circuits, or interfaces, which are appropriately configured together to execute the solution provided in this application. For example, the communication device 40 includes one or more processors 401 for implementing the method provided in this application.

[0182] Processor 401 can be a general-purpose processor or a dedicated processor. For example, processor 401 can be a baseband processor or a central processing unit (CPU). The baseband processor can be used to process communication protocols and communication data, while the CPU can be used to control the communication device 40 (such as a session management network element, access network device, mobility management network element, or chip, etc.), execute software programs, and process data from the software programs. Optionally, in one design, processor 401 may include program 405 (sometimes also referred to as code or instructions), which can be run on processor 401 to cause the communication device 40 to perform the methods described in the following embodiments. In yet another possible design, communication device 40 includes circuitry (not shown in FIG. 4) for implementing the functions of the session management network element, access network device, or mobility management network element in the following embodiments.

[0183] Optionally, the communication device 40 may include one or more memories 403. The memory 403 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM), cache, or other type of dynamic storage device capable of storing information and instructions. It may also be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media, or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but is not limited thereto. The memory provided in this application may generally be non-volatile. Optionally, the memory 403 stores a program 407 (sometimes referred to as code or instructions), which can be run on the processor 401 to cause the communication device 40 to perform the methods described in the following method embodiments.

[0184] Optionally, the processor 401 may include an AI module 406, and / or the memory 403 may include an AI module 408. The aforementioned AI modules are used to implement AI-related functions. The AI ​​modules can be implemented through software, hardware, or a combination of both. For example, the AI ​​module may include a RIC module. For example, the AI ​​module can be a near real-time RIC or a non-real-time RIC.

[0185] Optionally, data may also be stored in the processor 401 and / or the memory 403. The processor 401 and the memory 403 may be configured separately or integrated together.

[0186] Optionally, the communication device 40 may also include a transceiver 402 and / or an antenna 404. The processor 401, sometimes referred to as a processing unit, controls the communication device 40. The transceiver 402, sometimes referred to as a transceiver unit, transceiver, transceiver circuit, or transceiver, is used to realize the transmission and reception functions of the communication device 40 through the antenna 404.

[0187] It is understood that the composition shown in Figure 4 does not constitute a limitation on the communication device. In addition to the components shown in Figure 4, the communication device may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0188] The method provided in this application will now be described with reference to the accompanying drawings. Each network element in the following embodiments may include the components shown in Figure 4, which will not be elaborated upon further.

[0189] It is understood that in this application, the session management network element, access network device (such as the first access network device or the second access network device in the embodiments below), or mobility management network element may perform some or all of the steps in this application. These steps are merely examples, and this application may also perform other steps or variations thereof. Furthermore, the steps may be performed in different orders as presented in this application, and it is not necessary to perform all the steps in this application.

[0190] It is understood that the methods provided below in this application use a session management network element, an access network device (such as the first access network device or the second access network device in the following embodiments), and a mobility management network element as examples to illustrate the method. However, this application does not limit the execution subject of the interaction. For example, the session management network element in the method provided in the following embodiments of this application can also be a chip, chip system, or processor that supports the session management network element in implementing the method, or it can be a logical node, logical module, or software that can implement all or part of the terminal functions; the access network device in the method provided below in this application can also be a chip, chip system, or processor that supports the access network device in implementing the method, or it can be a logical node, logical module, or software that can implement all or part of the access network device functions; the mobility management network element in the method provided below in this application can also be a chip, chip system, or processor that supports the mobility management network element in implementing the method, or it can be a logical node, logical module, or software that can implement all or part of the mobility management network element functions.

[0191] As shown in Figure 5, a session management method provided in this application may include the following steps:

[0192] S501a: The first access network device sends first information to the session management network element. Correspondingly, the session management network element receives the first information from the first access network device.

[0193] In this application, the first access network device can be the access network device 102 in the communication system 1000 shown in Figure 1, and the session management network element can be the session management network element 101 in the communication system 1000 shown in Figure 1.

[0194] In this application, the session management network element can manage the terminal's first session. The first session is a session between the terminal and a user plane network element, and the first session passes through a first access network device. The first session can be used to transmit data sent by the terminal to the DN, or to transmit data sent by the DN to the terminal. For example, the first session can be a protocol data unit (PDU) session, or other sessions, without limitation. The terminal here can be terminal 104 in the communication system 1000 shown in Figure 1, and the user plane network element here can be user plane network element 105 in the communication system 1000 shown in Figure 1.

[0195] The aforementioned first information may indicate the mobility of the access network device management terminal; or the first information may indicate that the access network device is a terminal mobility anchor point; or the first information may indicate that when the first session is deactivated, the session management network element retains the identifier or address information of the access network device (session deactivation but keep RAN ID or RAN address); or the first information may indicate that when the first session is deactivated, the session management network element does not release the control plane connection; or the first information may indicate that when the first session is deactivated, the session management network element only releases the user plane information (session deactivation but only UP release); or the first information may indicate that when the first session is deactivated, the session management network element releases the user plane information but does not release the access network device information; or the first information may be used to establish the first session, and the first information may not carry the information of the mobility management network element, such as not carrying the identifier of the mobility management network element; or the first information may be used to indicate that the terminal does not enter the connection management idle state or the RRC idle state; or the first information may be used to indicate that the terminal enters the RRC inactive state. In this application, the address information of the access network device may include the IP address of the access network device or the fully qualified domain name (FQDN) of the access network device.

[0196] One possible implementation is that, in the case that the first session is a local session, the first access network device sends the first information to the session management network element.

[0197] In this application, a local session is a session that can only be established within a specific area; or a local session is a session that accesses or is routed to the local core network; or a local session is a session that accesses or is routed to the campus network. A local session is defined in contrast to a network session (or a non-local session). A network session is a session that accesses or is routed to the central core network. Therefore, a local session can also be understood as a session that does not access or is routed to the central core network.

[0198] For example, taking the communication system 1000 shown in Figure 1 as an example, a local session can be a session accessed or routed to the core network 107. For instance, a local session is a session established by the session management network element 101 for the terminal 104, which is a session between the terminal 104 and the user plane network element 105, and this session passes through the access network device 102 or the access network device 108. A network session can be a session accessed or routed to the core network 106. For instance, a network session is a session established by the session management network element (not shown in Figure 1) in the core network 106 for the terminal 104, which is a session between the terminal 104 and the user plane network element (not shown in Figure 1) in the core network 106, and this session passes through the access network device 102 or the access network device 108.

[0199] For example, the first access network device stores or pre-configures at least one of the following local network information: local network slice information, or local data network name (local DNN) information. The first access network device determines that the first session is a local session based on the local network information and the attribute information corresponding to the first session. The local network slice information includes local network slice selection assistance information (local NSSAI). The attribute information corresponding to the first session includes at least one of slice information or data network name (DNN) information. The slice information includes single network slice selection assistance information (S-NSSAI). For example, if the S-NSSAI of the first session belongs to the local NSSAI included in the local network information, the first access network device determines that the first session is a local session; if the S-NSSAI of the first session does not belong to the local NSSAI included in the local network information, the first access network device determines that the first session is not a local session. Alternatively, if the DNN information of the first session belongs to the local DNN information included in the local network information, the first access network device determines that the first session is a local session; if the DNN information of the first session does not belong to the local DNN information included in the local network information, the first access network device determines that the first session is not a local session.

[0200] Understandably, when the first session is a local session, the first access network device determines that it is the mobility anchor point of the first session, or that it is the mobility anchor point of the terminal; that is, the first access network device can manage the terminal's mobility. Therefore, the first access network device sends first information to the session management network element, so that the session management network element saves the information of the access network device to which the terminal is connected when the first session is deactivated, so that the session management network element can directly send a session activation request to that access network device when activating the first session.

[0201] Optionally, in specific applications, not all local sessions require the access network device as the terminal mobility anchor point. Therefore, the aforementioned local network information may include local NSSAIs or local DNNs that require the access network device as the terminal mobility anchor point. Alternatively, the aforementioned local network information may also include corresponding indication information to indicate which local NSSAIs or local DNNs require the access network device as the terminal mobility anchor point.

[0202] In this scenario, if the S-NSSAI of the first session belongs to a local NSSAI that requires the access network device to act as a terminal mobility anchor, or if the DNN information of the first session belongs to a local DNN that requires the access network device to act as a terminal mobility anchor, the first access network device sends the first information to the session management network element. If the S-NSSAI of the first session does not belong to a local NSSAI that requires the access network device to act as a terminal mobility anchor, or if the DNN information of the first session does not belong to a local DNN that requires the access network device to act as a terminal mobility anchor, the first access network device may or may not send the first information to the session management network element. In scenarios where the first access network device does not send the first information to the session management network element, the first information may indicate the access network device's management of the terminal's mobility, or indicate that the access network device is the terminal's mobility anchor point, or indicate that the session management network element saves the access network device's identifier or address information when the first session is deactivated, or indicate that the session management network element does not release the control plane connection when the first session is deactivated, or indicate that the session management network element only releases the user plane information when the first session is deactivated, or indicate that the session management network element releases the user plane information but not the access network device's information when the first session is deactivated, or indicate that the terminal does not enter the connection management idle state or the RRC idle state, or indicate that the terminal enters the RRC inactive state. In scenarios where the first access network device sends the first information to the session management network element, the first information is used to establish the first session, and the first information carries the information of the mobility management network element.

[0203] One possible implementation is that, when the terminal is permitted not to enter the Connection Management Idle State or the RRC Idle State, the first access network device sends first information to the Session Management Network element. For example, the terminal requests the first access network device not to enter the Connection Management Idle State or the RRC Idle State; the first access network device determines that the terminal is permitted not to enter the Connection Management Idle State or the RRC Idle State, and then sends the first information to the Session Management Network element. Another example is that the Mobility Management Network element instructs the first access network device that the terminal is permitted not to enter the Connection Management Idle State or the RRC Idle State; the first access network device determines that the terminal is permitted not to enter the Connection Management Idle State or the RRC Idle State, and then sends the first information to the Session Management Network element.

[0204] One possible implementation is that, when the terminal is permitted to enter the RRC inactive state, the first access network device sends first information to the session management network element. For example, the terminal requests to enter the RRC inactive state from the first access network device, the first access network device determines that the terminal is permitted to enter the RRC inactive state, and sends the first information to the session management network element. Another example is that the mobility management network element instructs the first access network device that the terminal is permitted to enter the RRC inactive state, the first access network device determines that the terminal is permitted to enter the RRC inactive state, and sends the first information to the session management network element. Yet another example is that the mobility management network element sends auxiliary information about the terminal entering the RRC inactive state to the first access network device, thereby the first access network device determines that the terminal is permitted to enter the RRC inactive state, and sends the first information to the session management network element.

[0205] In this application, the first information is sent during the establishment of the first session or during the deactivation of the first session.

[0206] In one possible implementation, the first access network device sends a first message to the session management network element. Correspondingly, the session management network element receives the first message from the first access network device. This first message is used to request the establishment of a first session. The first message includes first information, which may indicate that the access network device manages the mobility of the terminal; or that the access network device is a mobility anchor point for the terminal; or that the first information is used to indicate that the terminal does not enter a connection management idle state or an RRC idle state; or that the first information is used to indicate that the terminal enters an RRC inactive state. For example, the first message may be a session establishment message.

[0207] Another possible implementation involves the first access network device sending a second message to the session management network element. Correspondingly, the session management network element receives the second message from the first access network device. The second message requests the deactivation of the first session. The second message includes first information. The first information instructs the session management network element to save the identification or address information of the access network device when the first session is deactivated; or the first information instructs the session management network element not to release the control plane connection when the first session is deactivated; or the first information instructs the session management network element to release only the user plane information when the first session is deactivated; or the first information instructs the session management network element to release the user plane information but not the access network device's information when the first session is deactivated. For example, the second message is an update SM context request message.

[0208] Another possible implementation involves the session management network element sending a session resource release message to the first access network device. Upon receiving the session resource release message, the first access network device sends a session resource response message to the session management network element. This session resource response message includes first information. The first information may indicate that the session management network element saves the access network device's identifier or address information when the first session is deactivated; or the first information may indicate that the session management network element does not release the control plane connection when the first session is deactivated; or the first information may indicate that the session management network element only releases the user plane information when the first session is deactivated; or the first information may indicate that the session management network element releases the user plane information but does not release the access network device's information when the first session is deactivated.

[0209] S502: The session management network element obtains the identifier or address information of the second access network device.

[0210] Optionally, the session management network element obtains the identifier or address information of the second access network device, which can be replaced by the session management network element receiving the identifier or address information of the second access network device from the second access network device.

[0211] In this application, the second access network device is the access network device that the terminal accesses, or the access network device that the terminal is currently accessing, or the access network device that the terminal is connected to, or the access network device that the terminal accesses when the terminal's first session enters the deactivation state. The second access network device and the first access network device may be the same device or different devices. When the second access network device and the first access network device are different devices, the first access network device is the source access network device, and the second access network device is the target access network device. That is, the terminal first accesses the first access network device, and then the terminal switches to the second access network device. Taking the communication system 1000 shown in Figure 1 as an example, the second access network device is access network device 102 or access network device 108.

[0212] One possible implementation is that, when the second access network device and the first access network device are the same device, the session management network element obtains the identifier or address information of the second access network device from the second access network device during the establishment of the first session. For example, the identifier or address information of the second access network device is included in the message used to request the establishment of the first session (such as a session establishment message).

[0213] Another possible implementation is that when the second access network device and the first access network device are different devices, after the terminal switches to the second access network device, either the first access network device or the second access network device sends the identifier or address information of the second access network device to the session management network element.

[0214] Understandably, when the second access network device and the first access network device are different devices, if the session management network element stores the identifier or address information of the first access network device for the first session, then after obtaining the identifier or address information of the second access network device, the session management network element can replace the stored identifier or address information of the first access network device with the identifier or address information of the second access network device. For example, if the identifier or address information of the first access network device is stored in the context of the first session, the session management network element will replace the identifier or address information of the first access network device stored in the context of the first session with the identifier or address information of the second access network device. Alternatively, the session management network element can delete the identifier or address information of the first access network device from the context of the first session and store the identifier or address information of the second access network device in the context of the first session.

[0215] Understandably, this application does not restrict the execution order of S501a and S502. For example, S501a can be executed first, followed by S502, or S502 can be executed first, followed by S501a, or both S501a and S502 can be executed simultaneously.

[0216] S503: The session management network element saves the identifier or address information of the second access network device when the first session is deactivated.

[0217] One possible implementation is that the session management network element saves or does not delete the identifier or address information of the second access network device when the first session is deactivated, based on the first information. The identifier or address information of the second access network device can be stored in the context of the first session so that the session management network element can send an activation request to the second access network device when activating the first session.

[0218] Based on the method shown in Figure 5, the first access network device can send first information to the session management network element, enabling the session management network element to save the information of the access network device to which the terminal is connected when deactivating the first session. Therefore, when activating the first session, the session management network element can interact with the access network device instead of the mobility management network element, achieving rapid activation of the first session and avoiding long waiting times for service data.

[0219] In the method shown in Figure 5, the session management network element saves the identifier or address information of the second access network device when the first session is deactivated, according to the instruction of the first access network device. However, in specific applications, the session management network element can also determine itself whether to save the identifier or address information of the second access network device when the first session is deactivated. For example, the session management network element can save the identifier or address information of the second access network device when the first session is deactivated after determining that the first session is a local session. In other words, as shown in Figure 6A, the above S501a can be replaced by the following S501b, that is, the method provided in this application can include S501b, S502, and S503, but not S501a. It should be understood that S502 can be executed before S501b, after S501b, or simultaneously with S501b, without restriction.

[0220] S501b: The session management network element determines that the first session is a local session.

[0221] One possible implementation is that the session management network element stores or pre-configures at least one of the following local network information: local network slice information, or local DNN information. The session management network element determines that the first session is a local session based on the local network information and the attribute information corresponding to the first session. Specifically, refer to the description in S501a of the first access network device determining that the first session is a local session.

[0222] Furthermore, in practical applications, not all local sessions require the access network device as the terminal mobility anchor point. Therefore, the local network information stored or pre-configured by the session management network element may include local NSSAIs or local DNNs that require the access network device as the terminal mobility anchor point. Alternatively, the local network information stored or pre-configured by the session management network element may also include corresponding indication information to indicate which local NSSAIs or local DNNs require the access network device as the terminal mobility anchor point.

[0223] In this scenario, if the S-NSSAI of the first session belongs to the local NSSAI that requires the access network device as the terminal mobility anchor, or if the DNN information of the first session belongs to the local DNN information that requires the access network device as the terminal mobility anchor, the session management network element saves the identifier or address information of the second access network device when the first session is deactivated. If the S-NSSAI of the first session does not belong to the local NSSAI that requires the access network device as the terminal mobility anchor, or if the DNN information of the first session does not belong to the local DNN information that requires the access network device as the terminal mobility anchor, the session management network element saves the identifier or address information of the second access network device when the first session is deactivated.

[0224] Optionally, in one possible implementation of the method shown in Figure 5, if the session management network element determines to activate the first session, it can directly send a request to the second access network device without interacting with the mobility management network element. Therefore, the first session can be activated quickly, thereby reducing the waiting time for service data and improving user experience. Specifically, as shown in Figure 6A, the method shown in Figure 5 further includes the following steps:

[0225] S504: The user plane network element sends the second information to the session management network element. Correspondingly, the session management network element receives the second information from the user plane network element.

[0226] In this application, the second information indicates that data from the first session has been received. For example, after a user plane network element receives data from the first session (such as the first downlink data packet of a QoS flow of the first session) from the DN, it sends the second information to the session management network element. The second information may include the identifier of the first session or the N4 session identifier (N4 Session ID) corresponding to the first session. Optionally, the second information may also include QoS flow information of the data in the first session. For example, the second information is a data notification message, or the user plane network element sends a data notification message to the session management network element, and the data notification message includes the second information.

[0227] Optionally, after receiving the second information, the session management network element can send a corresponding response message, such as a data notification ack message, to the user plane network element.

[0228] S505: The session management network element sends a first request to the second access network device based on the second information. Correspondingly, the second access network device receives the first request from the session management network element.

[0229] In this application, the first request is used to request the activation of the first session. For example, the first request includes the identifier of the terminal and the identifier of the first session. The identifier of the terminal may be a temporary identifier of the terminal (UE temp ID).

[0230] Understandably, after receiving the first request, the second access network device can configure the air interface connection between itself and the terminal. The second access network device can also send an identifier of the first session to the terminal, enabling the terminal to perceive which session is active. The second access network device also sends the first address information of the first channel to the session management network element. The first channel is used for transmitting data of the first session between the second access network device and the user plane network element. The first address information includes the address information and port information of the second access network device. After receiving the first address information, the session management network element sends the first address information to the user plane network element, so that the user plane network element can send the data of the first session to the second access network device based on the first address information. The user plane network element also sends the second address information of the first channel to the session management network element. The second address information includes the address information and port information of the user plane network element. After receiving the second address information, the session management network element sends the second address information to the second access network device, so that the second access network device can send the data of the first session to the user plane network element based on the second address information.

[0231] Optionally, in the event of a first session activation failure—for example, if the second access network device indicates that the first session activation failed, or that the terminal was not paging, or that the terminal's context is lost, or that it cannot be connected—the session management network element may send a second request to the mobility management network element. This second request requests the access network device to which the terminal is connected. Upon receiving the second request, the mobility management network element may send information about the access network device to which the terminal is connected to to the session management network element, so that the session management network element can send a request to that access network device to activate the first session.

[0232] Understandably, in order to achieve mobility for the first access network device managing the terminal, the first access network device can send corresponding indication information to the mobility management network element to instruct it to maintain the terminal's communication connection, or to not release the terminal's communication connection, or to not enter the connection management idle state, or to indicate the existence of a local session, thereby preventing the mobility management network element from releasing the terminal's communication connection. Specifically, this can be illustrated in the method shown in Figure 6B.

[0233] As shown in Figure 6B, another session management method provided in this application may include the following steps:

[0234] S601: The first access network device determines that the terminal's first session is a local session.

[0235] In this application, the first access network device may be the access network device 102 in the communication system 1000 shown in FIG1, and the terminal may be the terminal 104 in the communication system 1000 shown in FIG1.

[0236] In this application, the first session is a session between the terminal and a user plane network element, and the first session passes through a first access network device. The first session can be used to transmit data sent by the terminal to the DN, or to transmit data sent by the DN to the terminal. For example, the first session is a PDU session, or other sessions, without limitation. The user plane network element here can be user plane network element 105 in the communication system 1000 shown in Figure 1.

[0237] In this application, a local session is a session that can only be established in a specific area or within a particular area; or a local session is a session that accesses or is routed to the local core network; or a local session is a session that accesses or is routed to the campus network. A local session is defined in contrast to a network session (or a non-local session). A network session is a session that accesses or is routed to the central core network. Therefore, a local session can also be understood as a session that does not access or is routed to the central core network. For example, taking the communication system 1000 shown in Figure 1 as an example, a local session is a session that accesses or is routed to the core network 107, and a network session is a session that accesses or is routed to the core network 106.

[0238] One possible implementation is that the first access network device stores or pre-configures at least one of the following local network information: local network slice information, or local DNN information. The first access network device determines that the first session is a local session based on the local network information and the attribute information corresponding to the first session. For details, please refer to the corresponding description in S501a above, which will not be repeated here.

[0239] S602: The first access network device sends third information to the mobility management network element. Correspondingly, the mobility management network element receives the third information from the first access network device.

[0240] In this application, the mobility management network element is located in the central core network. For example, the mobility management network element is the mobility management network element 103 in the communication system 1000 shown in Figure 1.

[0241] In this application, the third information indicates that the terminal's communication connection should be maintained, or that the terminal's communication connection should not be released, or that the terminal should not enter the connection management idle state, or that a local session exists. The aforementioned communication connection of the terminal can refer to the communication connection between the terminal and the first access network device, or the communication connection between the first access network device and the mobility management network element; this communication connection can also be referred to as an AN connection.

[0242] Understandably, when the first session is a local session, the first access network device determines that it is the mobility anchor point of the first session, or that it is the mobility anchor point of the terminal; that is, the first access network device can manage the terminal's mobility. Therefore, the first access network device sends third information to the mobility management element to prevent the mobility management element from releasing the terminal's communication connection.

[0243] Optionally, in specific applications, not all local sessions require the access network device as the terminal mobility anchor point. Therefore, the local network information in S601 may include local NSSAIs or local DNNs that require the access network device as the terminal mobility anchor point. Alternatively, the local network information in S601 may also include corresponding indication information to indicate which local NSSAIs or local DNNs require the access network device as the terminal mobility anchor point. In this scenario, if the S-NSSAI of the first session belongs to a local NSSAI that requires the access network device as the terminal mobility anchor point, or if the DNN information of the first session belongs to a local DNN that requires the access network device as the terminal mobility anchor point, the first access network device sends third information to the mobility management network element. If the S-NSSAI of the first session does not belong to a local NSSAI that requires the access network device as the terminal mobility anchor point, or if the DNN information of the first session does not belong to a local DNN that requires the access network device as the terminal mobility anchor point, the first access network device does not send third information to the mobility management network element.

[0244] S603: The mobility management network element determines, based on third information, not to trigger the release of the terminal's communication connection.

[0245] One possible implementation involves the mobility management element (MLE) determining, based on third-party information, not to trigger the release of the terminal's communication connection if a local network slice exists in the terminal's allowed network slice information (such as allowed NSSAI). The allowed network slice information can be obtained by the MLE during terminal registration. In other words, if no local network slice exists in the terminal's allowed network slice information, the MLE can choose to release the terminal's communication connection, allowing the MLE in the core network to reasonably control the terminal's communication connection status.

[0246] Understandably, a terminal can periodically send registration messages to the mobility management element (MMI) to indicate that it is maintaining a connection with the network. Typically, the MMI will release the terminal's communication connection upon receiving the periodic registration message. However, if the MMI receives third-party information, it will not release the terminal's communication connection even if it receives the aforementioned registration message.

[0247] Understandably, in practical applications, the terminal's communication connection can be released by either the Mobility Management Network (MMN) or the First Access Network (BARC) device. Therefore, when the MMN does not trigger the release of the terminal's communication connection, the BARC device can manage the terminal's mobility. The terminal will not enter a connection management idle state or an RRC idle state, but it can enter an RRC inactive state or an RRC connected state.

[0248] Based on the method shown in Figure 6B, when the first session is a local session, the first access network device can determine that it manages the terminal's mobility or that it acts as the mobility anchor point for the first session. Therefore, the first access network device can instruct the mobility management element to maintain the terminal's communication connection, or instruct it not to release the terminal's communication connection, or instruct the terminal not to enter a connection management idle state, or instruct that a local session exists, to avoid the mobility management element releasing the terminal's communication connection. It is understandable that when the first access network device manages the terminal's mobility, if the session management element activates the first session, it can interact with the first access network device instead of the mobility management element to quickly activate the first session, reduce the waiting time for service data, and improve the user experience.

[0249] It is understandable that the method shown in Figure 6B can be combined with the method shown in Figure 5, or with the method shown in Figure 6A.

[0250] For example, taking the method shown in Figure 6B in combination with the method shown in Figure 5 as an example, S601 to S603 can be executed before S501a, S601 to S603 can be executed after S501a, and S601 to S603 can also be executed simultaneously with S501a, without any restrictions.

[0251] For example, taking the method shown in Figure 6B in combination with the method shown in Figure 6A as an example, S601 to S603 can be executed before S501b, after S501b, or simultaneously with S501b, without any restrictions.

[0252] To better understand the methods shown in Figures 5, 6A, and 6B above, the session management method provided in this application will be introduced below in conjunction with the session establishment process, session deactivation process, and session activation process.

[0253] Figure 7 illustrates another session management method provided in this application. In this method, during the establishment of a first session, the first access network device may indicate the mobility of the managed terminal to the session management network element, or notify the access network device to act as a terminal mobility anchor point. This allows the session management network element to save the identifier or address information of the first access network device when the first session is deactivated, and to directly send an activation request for the first session to the first access network device when activating the first session. Alternatively, during session establishment, the message sent by the first access network device to the session management network element does not carry information about the mobility management network element. This allows the session management network element to save the identifier or address information of the first access network device when the first session is deactivated, and to directly send an activation request for the first session to the first access network device when activating the first session. The terminal in the method shown in Figure 7 can be terminal 104 in the communication system 1000 shown in Figure 1; the mobility management network element in the method shown in Figure 7 can be mobility management network element 103 in the communication system 1000 shown in Figure 1; the first access network device in the method shown in Figure 7 can be access network device 102 in the communication system 1000 shown in Figure 1; the session management network element in the method shown in Figure 7 can be session management network element 101 in the communication system 1000 shown in Figure 1; the user plane network element in the method shown in Figure 7 can be user plane network element 105 in the communication system 1000 shown in Figure 1; and the second access network device in the method shown in Figure 7 can be access network device 102 or access network device 108 in the communication system 1000 shown in Figure 1. This method may include the following steps:

[0254] S701: The terminal registers in the core network.

[0255] When a terminal joins the network, it can register with the core network. For example, the terminal sends registration information to the first access network device. After receiving the registration information, the first access network device can obtain the information of the mobility management network element selected by the terminal from the selected function network element, and send the registration information to the mobility management network element to register the terminal's information with the mobility management network element.

[0256] During the terminal registration process, the mobility management network element (MMI) or the first access network (ANR) device can assign a temporary identifier (UE temp ID) to the terminal. This temporary identifier can be used by the ANR device and the core network element to identify the terminal. After the terminal registration process is completed, both the ANR device and the MMI store the terminal context. The terminal context stored in the ANR device includes the identifier of the MMI and the temporary identifier of the terminal. The terminal context stored in the MMI includes the temporary identifier of the terminal.

[0257] Optionally, the mobility management network element sends its identifier and the terminal's temporary identifier to the UDR network element, so that other core network elements can query the mobility management network element based on the terminal's temporary identifier.

[0258] During the terminal registration process, the mobility management network element also sends mobility restriction information to the terminal. This mobility restriction information includes at least one of the following: information about the allowed area or the non-allowed area. When the terminal is in the allowed area, it can initiate session-related services. For example, the terminal can initiate the following session establishment process:

[0259] S702: The terminal sends message 1 to the first access network device. Correspondingly, the first access network device receives message 1 from the terminal.

[0260] Message 1 includes a Session Management Non-Access Stratum (NAS) message (SM NAS message 1) and attribute information corresponding to the first session. SM NAS message 1 can be a session establishment message. For example, SM NAS message 1 includes one or more pieces of information such as the identifier of the first session, the requested session type, or the requested service and session continuity (SSC) mode. For a description of the first session and its corresponding attribute information, please refer to the corresponding descriptions in the methods shown in Figure 5 or Figure 6A above.

[0261] After receiving message 1, if the first access network device determines that the first session is not an existing session based on the type of SM NAS message 1, it can send a request to the NRF network element or the Select Function network element to request the determination of the session management network element managing the first session. After obtaining the session management network element determined by the NRF network element or the Select Function network element, the first access network device can store the correspondence between the identifier of the first session and the identifier of the session management network element.

[0262] Optionally, message 1 is an RRC message.

[0263] S703: The first access network device determines that the terminal's first session is a local session.

[0264] Understandably, the specific process of S703 is similar to that of S601 above, and you can refer to the corresponding description in S601.

[0265] S704: The first access network device sends a create session management context (SM context) request message to the session management network element. Correspondingly, the session management network element receives the create session management context request message from the first access network device.

[0266] The Create Session Management Context Request message may include the terminal's temporary identifier and SM NAS message 1.

[0267] Understandably, in order for the session management network element to save the information of the access network device to which the terminal is connected when the first session is deactivated, the session management context request message or SM NAS message 1 also includes first information. This first information may indicate that the access network device manages the terminal's mobility; or it may indicate that the access network device is the terminal's mobility anchor point; or it may not carry information about the mobility management network element, such as its identifier; or it may indicate that the terminal does not enter the connection management idle state or the RRC idle state; or it may indicate that the terminal enters the RRC inactive state. For details, please refer to the corresponding description in S501a.

[0268] After receiving a request message to create a session management context, the session management network element can establish the first session. For example, the session management network element can perform the following steps:

[0269] S705: The session management network element subscribes to or queries the mobility management network element whether the terminal is in an allowed area or a local area data network (LADN).

[0270] In this application, step S705 is optional.

[0271] One possible implementation is that if the Session Management Context Request message includes the identifier of the Mobility Management Element (MME), the MME can directly subscribe to or query the MME to determine whether the terminal is in an allowed area or LADN, in order to decide whether to accept the session establishment.

[0272] For example, if the terminal is in an allowed area or LADN, the session management network element accepts the session establishment; if the terminal is in an unallowed area or is not in LADN, the session management network element rejects the session establishment.

[0273] Another possible implementation is that if the Create Session Management Context Request message does not include the identifier of the Mobility Management Element (MME), the Session Management Element can query the MME identifier from the UDM element based on the terminal's temporary identifier, and subscribe to or query the MME element to determine whether the terminal is in an allowed area or LADN, in order to determine whether to accept the session establishment.

[0274] For example, the session management network element obtains the terminal's subscription data from the UDM network element based on the terminal's temporary identifier, and determines whether to accept the session establishment based on the terminal's subscription data and the DNN included in the attribute information corresponding to the first session. For instance, if the DNN included in the attribute information corresponding to the first session corresponds to a local service, and the session management network element queries the mobility management network element and finds that the terminal is in a LADN, then the session management network element accepts the session establishment; if the DNN included in the attribute information corresponding to the first session corresponds to a local service, and the session management network element queries the mobility management network element and finds that the terminal is not in a LADN, then the session management network element rejects the session establishment.

[0275] Understandably, if the session management network element accepts the session establishment, it can perform the following steps:

[0276] S706: Session management network element selects policy control network elements (such as PCF network elements) to establish session management policies.

[0277] If the network supports dynamic policy control and charging (PCC), the session management element can perform policy control element selection to establish session management policies. For example, the session management element can execute a session management policy establishment procedure to establish a session with the policy control element and obtain the session's PCC criteria. If the network does not support dynamic PCC, the session management element can apply local policies.

[0278] Optionally, the session management network element executes a session management policy modification process to report session-related events to the policy control network element.

[0279] S707: The session management network element selects the user plane network element and initiates the N4 session establishment / modification process.

[0280] The session management network element can select user plane network elements based on the deployment scenario. For example, the session management network element can choose user plane network elements located in the central core network or distributed user plane network elements located near the first access network device. When selecting user plane network elements, the session management network element can also consider the capabilities of the user plane network elements. Furthermore, the session management network element can also assign corresponding IP addresses to the first session or terminal.

[0281] Understandably, if SM NAS message 1 is an initial request, the session management network element initiates an N4 session establishment process to the user plane network element; if SM NAS message 1 is not an initial request, the session management network element initiates an N4 session modification process to the user plane network element.

[0282] For example, the session management network element sends an N4 session establishment / modification request to the user plane network element to establish a first session. The N4 session establishment / modification request may carry packet detection, enforcement, and reporting rules provided by the session management network element for the first session. Optionally, if the core network (CN) tunnel information (CN tunnel Info) is allocated by the session management network element, the N4 session establishment / modification request may carry CN tunnel info, such as the third address information of the first channel. The third address information includes the address information and port information of the user plane network element. After receiving the N4 session establishment / modification request, the user plane network element sends an N4 session establishment / modification response to the session management network element. If the CN tunnel info is allocated by the user plane network element, or if the N4 session establishment / modification request does not carry CN tunnel info, the N4 session establishment / modification response may carry the CN tunnel info allocated by the user plane network element.

[0283] S708: The session management network element sends a Create Session Management Context response message to the first access network device. Correspondingly, the first access network device receives the Create Session Management Context response message from the session management network element.

[0284] The session management context creation response message may include the terminal's temporary identifier, N2 session management information (N2 SM info), and SM NAS message 2. The N2 SM info may include the identifier of the first session, the QoS flow identifier (QFI), the QoS profile, and CN tunnel information. SM NAS message 2 may be a session establishment accept message. SM NAS message 2 may include QoS rules, QoS parameters, or IP address information.

[0285] S709: The first access network device performs radio interface resource configuration for the terminal based on the N2 SM info and sends SM NAS message 2 to the terminal. Correspondingly, the terminal receives SM NAS message 2 from the first access network device.

[0286] S710: The first access network device sends an update SM context request message 1 to the session management network element. Correspondingly, the session management network element receives the update SM context request message 1 from the first access network device.

[0287] The Update Session Management Context Request message 1 may include the identifier of the first session, AN tunnel information (AN tunnel Info), and information about the QoS flows received by the first access network device. The AN tunnel Info may include the fourth address information of the first channel. The fourth address information includes the address information and port information of the first access network device.

[0288] S711: The session management network element sends an N4 session modification request to the user plane network element. Correspondingly, the user plane network element receives the N4 session modification request from the session management network element.

[0289] The N4 session modification request may include AN tunnel Info and the corresponding data forwarding rules.

[0290] S712: The user plane network element sends an N4 session modification response to the session management network element. Correspondingly, the session management network element receives the N4 session modification response from the user plane network element.

[0291] S713: The session management network element sends an update SM context response message 1 to the first access network device. Correspondingly, the first access network device receives the update SM context response message 1 from the session management network element.

[0292] At this point, the first session has been successfully established, and its session status is active.

[0293] S714: The first access network device sends third information to the mobility management network element. Correspondingly, the mobility management network element receives the third information from the first access network device.

[0294] Understandably, after receiving the third information, the mobility management network element can determine whether to trigger the release of the terminal's communication connection based on the third information. For details, please refer to the descriptions of S602 to S603 above.

[0295] It is understandable that Figure 7 is drawn with S714 executed after S713, but in specific applications, S714 can be executed after S703. For example, S714 can be executed after S703 and before S704, or S714 and S704 can be executed simultaneously, or S714 can be executed after S704, without any restrictions.

[0296] Understandably, after the first session is successfully established, the session management network element or the first access network device can deactivate the first session, thus changing its session state to inactive. For example, the session management network element and the first access network device can perform the following steps:

[0297] S715: The session management network element and the first access network device execute the deactivation process of the first session. When the first session is deactivated, the session management network element saves the identifier or address information of the first access network device.

[0298] In this application, the first session can be deactivated by either the first access network device or the session management network element. This will be explained in detail below.

[0299] In one possible implementation, the first access network device sends an Update Session Management Context Request Message 2 to the session management network element. Correspondingly, the session management network element receives the Update Session Management Context Request Message 2 from the first access network device. The Update Session Management Context Request Message 2 may include the identifier of the first session and a session deactivation indication. Upon receiving the Update Session Management Context Request Message 2, the session management network element triggers the release of the user plane information of the first session. For example, it triggers the user plane network element to delete the fourth address information. The session management network element can also, based on the first information in S704, save or not delete the identifier or address information of the first access network device during the deactivation of the first session. Subsequently, the session management network element can send an Update Session Management Context Response Message 2 to the first access network device to indicate whether the deactivation of the first session is complete.

[0300] Another possible implementation is that the session management network element sends a session resource release (e.g., N2 session resource release) message to the first access network device. Upon receiving the session resource release message, the first access network device can delete the third address information and send a session resource release response (e.g., N2 session resource response) message to the session management network element to indicate whether the deactivation of the first session is complete. The session management network element also triggers the release of the user plane information of the first session; for example, it triggers the user plane network element to delete the fourth address information. The session management network element can also, based on the first information in S704, save or not delete the identifier or address information of the first access network device during the deactivation of the first session.

[0301] Understandably, after the first session is deactivated, the first access network device includes the context information of the first session, which includes the identifier of the first session and the identifier of the session management network element. The session management network element includes the context information of the first session, which includes the identifier of the first session and the identifier or address information of the first access network device.

[0302] Understandably, if the terminal switches to the second access network device before S715, the first or second access network device can send the identifier or address information of the second access network device to the session management network element. The session management network element stores the identifier or address information of the second access network device in S715.

[0303] Understandably, after the first session is deactivated, the session management network element can reactivate the first session, making its session state active again. For example, the session management network element and the user plane network element can perform the following steps:

[0304] S716: The user plane network element sends the second information to the session management network element. Correspondingly, the session management network element receives the second information from the user plane network element.

[0305] S717: The session management network element sends a first request to the first access network device based on the second information. Correspondingly, the first access network device receives the first request from the session management network element.

[0306] One possible implementation is that if the context information of the first session stored by the session management network element includes the identifier or address information of the first access network device, the session management network element sends a first request to the first access network device. The first request is a session active request. The first request may include the identifier of the terminal and the identifier of the first session.

[0307] Understandably, if the terminal is in an RRC inactive state, such as when the air interface connection between the terminal and the first access network device is released, but the first access network device maintains the terminal's context, the first access network device can paging the terminal, allowing the terminal to restore its RRC connection with the first access network device. Subsequently, the first access network device can configure its air interface connection with the terminal and send the identifier of the first session to the terminal, enabling the terminal to perceive which session is active. The first access network device also sends the address information of the second channel to the session management network element. The second channel is used for transmitting the first session's data between the first access network device and the user plane network element. The address information of the second channel includes the address information and port information of the first access network device. After receiving the address information of the second channel, the session management network element sends the address information of the second channel to the user plane network element, so that the user plane network element can send the first session's data to the first access network device based on this address information. The user plane network element also sends the address information of the second channel to the session management network element. The address information sent by the user plane network element includes the address information and port information of the user plane network element. After receiving the address information, the session management network element sends the address information to the first access network device so that the first access network device can send the data of the first session to the user plane network element according to the address information.

[0308] Understandably, if the terminal is in an RRC inactive state, and it was connected to the first access network device before entering this state, the first access network device maintains the terminal's context. If the terminal is currently within the coverage area of ​​the second access network device, the first access network device performs RAN paging, enabling the terminal to restore the RRC connection with the second access network device. The first access network device also sends the terminal's context and a first request to the second access network device. Subsequently, the second access network device can configure its air interface connection with the terminal and send the identifier of the first session to the terminal, allowing the terminal to perceive which session is active. The second access network device also sends first address information to the session management network element. After receiving the first address information, the session management network element sends the first address information to the user plane network element. The user plane network element sends the second address information of the first channel to the session management network element. After receiving the second address information, the session management network element sends the second address information to the second access network device.

[0309] Understandably, if the session management network element in S715 stores the identifier or address information of the second access network device, then in S717, the session management network element sends a first request to the second access network device. After receiving the first request, the second access network device can configure its air interface connection with the terminal and send the identifier of the first session to the terminal, enabling the terminal to perceive which session is active. The second access network device also sends first address information to the session management network element. After receiving the first address information, the session management network element sends the first address information to the user plane network element. The user plane network element sends the second address information of the first channel to the session management network element. After receiving the second address information, the session management network element sends the second address information to the second access network device.

[0310] Understandably, the specific processes of S716 to S717 are similar to those of S504 to S505. Please refer to the corresponding descriptions in S504 to S505 above, and we will not repeat them here.

[0311] In the method shown in Figure 7, the first access network device sends a corresponding instruction to the session management network element during the establishment of the first session, so that the session management network element saves the identifier or address information of the first access network device when the first session is deactivated. Besides the above method, the first access network device can also send a corresponding instruction to the session management network element during the deactivation of the first session, so that the session management network element saves the identifier or address information of the first access network device when the first session is deactivated.

[0312] For example, the Create Session Management Context Request message or SM NAS message 1 in S704 may not carry the first information. Instead, the first information may be carried in the Update Session Management Context Request message 2 or the Session Resource Release response in S715. The first information in S715 may instruct the first session to save the identifier or address information of the access network device when deactivating; or instruct the first session not to release the control plane connection when deactivating; or instruct the first session to release only the user plane information when deactivating; or instruct the first session to release the user plane information without releasing the access network device information when deactivating. Subsequently, the session management network element saves the identifier or address information of the first access network device when the first session is deactivated. In this example, the first access network device and the second access network device are the same device. The remaining steps can be referred to the description in the method shown in Figure 7, and will not be repeated here.

[0313] In addition to the above methods, the first access network device may also choose not to send indication information to the session management network element. The session management network element can determine whether to save the identifier or address information of the first access network device when the first session is deactivated based on its stored or pre-configured local network information and the attribute information corresponding to the first session.

[0314] For example, the session management context creation request message or SM NAS message 1 in S704 above may not carry the first information. After S704 and before S715, the session management network element can determine that the first session is a local session. For example, the session management network element determines that the first session is a local session based on its stored or pre-configured local network information and the attribute information corresponding to the first session. For details, please refer to the corresponding description in S504b. Subsequently, in S715, the session management network element saves the identifier or address information of the first access network device when the first session is deactivated. The remaining steps can be referred to the description in the method shown in Figure 7, and will not be repeated here.

[0315] In the methods shown in Figures 5 to 7, the first access network device sends a corresponding instruction to the session management network element, or, if the session management network element determines that the first session is a local session, it saves the identifier or address information of the second access network device when the first session is deactivated. In specific applications, the session management network element can also instruct or request the mobility of the first access network device's management terminal and save the identifier or address information of the second access network device when the first session is deactivated. Specifically, this can be described in the method shown in Figure 8.

[0316] As shown in Figure 8, another session management method provided in this application may include the following steps:

[0317] S801: The session management network element sends first information to the first access network device. Correspondingly, the first access network device receives the first information from the session management network element.

[0318] In this application, the first access network device can be access network device 102 in the communication system 1000 shown in Figure 1, and the session management network element can be session management network element 101 in the communication system 1000 shown in Figure 1. The session management network element can manage the first session of the terminal.

[0319] The first information can be used to indicate the mobility of the access network device management terminal, or to request the mobility of the access network device management terminal, or to indicate that interoperability with the mobility management network element is not supported, or to indicate that the terminal should not enter the connection management idle state or the RRC idle state, or to request that the terminal should not enter the connection management idle state or the RRC idle state. The terminal can be terminal 104 in the communication system 1000 shown in Figure 1.

[0320] One possible implementation is that the first information is sent by the session management network element to the first access network device during the establishment of the first session. For example, the first information is included in the session management context creation response message.

[0321] One possible implementation is that the session management network element sends first information to the first access network device according to the instruction of the policy control network element (such as the PCF network element), or if the session management network element is a local session in the case of the first session. For a description of the local session, please refer to the corresponding description in the method shown in Figure 5.

[0322] As an example, the policy control network element sends first policy information to the session management network element. This first policy information instructs the first session to maintain the control plane connection (CP connection) during session deactivation. Upon receiving the first policy information, the session management network element sends first information to the first access network device based on this information.

[0323] As another example, the session management network element determines that the first session is a local session and sends the first information to the first access network device. The session management network element can determine that the first session is a local session based on its stored or pre-configured local network information and the attribute information corresponding to the first session. For details, please refer to the corresponding description in S501b.

[0324] Optionally, in specific applications, not all local sessions require the access network device as the terminal mobility anchor. Therefore, the local network information stored or pre-configured by the session management network element may include local NSSAIs or local DNNs that require the access network device as the terminal mobility anchor. Alternatively, the local network information stored or pre-configured by the session management network element may also include corresponding indication information to indicate which local NSSAIs or local DNNs require the access network device as the terminal mobility anchor. In this scenario, if the S-NSSAI of the first session belongs to a local NSSAI that requires the access network device as the terminal mobility anchor, or if the DNN information of the first session belongs to a local DNN that requires the access network device as the terminal mobility anchor, the session management network element sends the first information to the first access network device. If the S-NSSAI of the first session does not belong to a local NSSAI that requires the access network device as the terminal mobility anchor, or if the DNN information of the first session does not belong to a local DNN that requires the access network device as the terminal mobility anchor, the session management network element does not send the first information to the first access network device.

[0325] Understandably, after receiving the first information, the first access network device can determine, based on the first information, whether the terminal will not enter the connection management idle state or whether the terminal can enter the RRC inactive state. That is, the first access network device determines that it will manage the terminal's mobility, or the first access network device will not trigger the release of the terminal's communication connection.

[0326] Optionally, the first access network device sends third information to the session management network element. This third information is used to confirm the mobility of the terminal managed by the access network device, or to confirm that the terminal does not enter a connection management idle state or an RRC idle state. Therefore, after receiving the third information, the session management network element can determine the mobility of the terminal managed by the first access network device.

[0327] Optionally, the first access network device may send a fourth message to the mobility management network element. This fourth message may indicate that the terminal's communication connection should be maintained, or that the terminal's communication connection should not be released, or that the terminal should not enter a connection management idle state, or that a local session exists. This allows the mobility management network element to determine, based on the fourth message, not to trigger the release of the terminal's communication connection. For details, please refer to the corresponding descriptions in S602 to S603 above.

[0328] S802: The session management network element obtains the identifier or address information of the second access network device.

[0329] The second access network device is either the access network device the terminal accesses, the access network device the terminal is currently accessing, the access network device the terminal is connected to, or the access network device the terminal accesses when the terminal's first session enters the deactivation state. The second access network device and the first access network device can be the same device or different devices. When the second access network device and the first access network device are different devices, the first access network device is the source access network device, and the second access network device is the target access network device. That is, the terminal first accesses the first access network device, and then the terminal switches to the second access network device. Taking the communication system 1000 shown in Figure 1 as an example, the second access network device is access network device 102 or access network device 108.

[0330] One possible implementation is that, when the second access network device and the first access network device are the same device, the session management network element obtains the identifier or address information of the second access network device from the second access network device during the establishment of the first session. For example, the identifier or address information of the second access network device is included in the message used to request the establishment of the first session (such as a session establishment message).

[0331] Another possible implementation is that when the second access network device and the first access network device are different devices, when the terminal switches to the second access network device, either the first access network device or the second access network device sends the identifier or address information of the second access network device to the session management network element.

[0332] Understandably, this application does not restrict the execution order of S801 and S802. For example, S801 can be executed first, followed by S802, or S802 can be executed first, followed by S801, or both S801 and S802 can be executed simultaneously.

[0333] S803: The session management network element saves the identifier or address information of the second access network device when the first session is deactivated.

[0334] One possible implementation is that the session management network element saves the identifier or address information of the second access network device when the first session is deactivated, based on third information. The identifier or address information of the second access network device can be stored in the context of the first session, so that the session management network element can send an activation request to the second access network device when activating the first session.

[0335] Based on the method shown in Figure 8, the session management network element can indicate / request the mobility of the terminal managed by the access network device or indicate / request the terminal not to enter the connection management idle state or RRC idle state to the first access network device, so that the session management network element can save the information of the access network device to which the terminal is connected when the first session is deactivated. Therefore, when activating the first session, the session management network element can interact with the access network device instead of the mobility management network element, thereby quickly activating the first session.

[0336] Optionally, as shown in Figure 9, in one possible implementation of the method shown in Figure 8, the method further includes the following steps:

[0337] S804: The user plane network element sends the second information to the session management network element. Correspondingly, the session management network element receives the second information from the user plane network element.

[0338] S805: The session management network element sends a first request to the second access network device based on the second information. Correspondingly, the second access network device receives the first request from the session management network element.

[0339] Understandably, the specific processes of S804 to S805 are similar to those of S504 to S505 above. Please refer to the corresponding descriptions in S504 to S505 above, and they will not be repeated here.

[0340] To better understand the methods shown in Figure 8 or Figure 9 above, the session management method provided in this application will be introduced below in conjunction with the session establishment process, session deactivation process, and session activation process.

[0341] Figure 10 illustrates another session management method provided in this application. In this method, during the establishment of the first session, the session management network element can indicate or request the mobility of the access network device's management terminal from the first access network device, or indicate / request the first access network device that the terminal should not enter the connection management idle state or the RRC idle state. Subsequently, the session management network element can save the identifier or address information of the first access network device when the first session is deactivated, and directly send an activation request for the first session to the first access network device when activating the first session. The terminal in the method shown in Figure 10 below can be terminal 104 in the communication system 1000 shown in Figure 1; the mobility management network element in the method shown in Figure 10 can be mobility management network element 103 in the communication system 1000 shown in Figure 1; the first access network device in the method shown in Figure 10 can be access network device 102 in the communication system 1000 shown in Figure 1; the session management network element in the method shown in Figure 10 can be session management network element 101 in the communication system 1000 shown in Figure 1; the user plane network element in the method shown in Figure 10 can be user plane network element 105 in the communication system 1000 shown in Figure 1; and the second access network device in the method shown in Figure 10 can be access network device 102 or access network device 108 in the communication system 1000 shown in Figure 1. This method may include the following steps:

[0342] S1001: The terminal registers in the core network.

[0343] S1002: The terminal sends message 1 to the first access network device. Correspondingly, the first access network device receives message 1 from the terminal.

[0344] Understandably, the specific processes of S1001 to S1002 are similar to those of S701 to S702 above, and you can refer to the corresponding descriptions in S701 to S702.

[0345] S1003: The first access network device sends a create session management context (SM context) request message to the session management network element. Correspondingly, the session management network element receives the create session management context request message from the first access network device.

[0346] The Create Session Management Context Request message may include the terminal's temporary identifier and SM NAS message 1.

[0347] After receiving a request message to create a session management context, the session management network element can establish the first session. For example, the session management network element can perform the following steps:

[0348] S1004: The session management network element subscribes to or queries the mobility management network element whether the terminal is in an allowed area or a local area data network (LADN).

[0349] S1005: Session management network element selects policy control network element (such as PCF network element) to establish session management policy.

[0350] S1006: The session management network element selects the user plane network element and initiates the N4 session establishment / modification process.

[0351] Understandably, the specific processes of S1004 to S1006 are similar to those of S705 to S707 above, and you can refer to the corresponding descriptions in S705 to S707.

[0352] S1007: The session management network element sends a Create Session Management Context response message to the first access network device. Correspondingly, the first access network device receives the Create Session Management Context response message from the session management network element.

[0353] The session management context creation response message may include a temporary identifier for the terminal, N2 session management information (N2 SM info), SM NAS message 2, and first information. The N2 SM info may include the identifier of the first session, QFI, QoS profile, and CN tunnel Info, etc. SM NAS message 2 may be a session establishment accept message. SM NAS message 2 may include QoS rule, QoS parameter information, or IP address information, etc. The first information may indicate the mobility of the access network device management terminal, or it may be used to request the mobility of the access network device management terminal, or it may be used to indicate that interoperability with the mobility management network element is not supported. Further details regarding the first information can be found in section S801.

[0354] S1008: The first access network device determines, based on the first information, that the terminal does not enter the connection management idle state, or determines that the terminal can enter the RRC inactive state.

[0355] S1009: The first access network device performs radio interface resource configuration for the terminal based on the N2 SM info and sends SM NAS message 2 to the terminal. Correspondingly, the terminal receives SM NAS message 2 from the first access network device.

[0356] S1010: The first access network device sends an update SM context request message 1 to the session management network element. Correspondingly, the session management network element receives the update SM context request message 1 from the first access network device.

[0357] S1011: The session management network element sends an N4 session modification request to the user plane network element. Correspondingly, the user plane network element receives the N4 session modification request from the session management network element.

[0358] S1012: The user plane network element sends an N4 session modification response to the session management network element. Correspondingly, the session management network element receives the N4 session modification response from the user plane network element.

[0359] S1013: The session management network element sends an update SM context response message 1 to the first access network device. Correspondingly, the first access network device receives the update SM context response message 1 from the session management network element.

[0360] Understandably, the specific processes of S1010 to S1013 are similar to those of S710 to S713 above, and you can refer to the corresponding descriptions in S710 to S713.

[0361] Optionally, the first access network device sends third information to the mobility management network element, causing the mobility management network element to determine that it will not trigger the release of the terminal's communication connection. For details, please refer to the descriptions of S602 to S603 above.

[0362] At this point, the first session has been successfully established, and its session status is active.

[0363] Understandably, after the first session is successfully established, the session management network element or the first access network device can deactivate the first session, thus changing its session state to inactive. For example, the session management network element and the first access network device can perform the following steps:

[0364] S1014: The session management network element and the first access network device execute the deactivation process of the first session. When the first session is deactivated, the session management network element saves the identifier or address information of the first access network device.

[0365] Understandably, after the first session is deactivated, the session management network element can reactivate the first session, making its session state active again. For example, the session management network element and the user plane network element can perform the following steps:

[0366] S1015: The user plane network element sends the second information to the session management network element. Correspondingly, the session management network element receives the second information from the user plane network element.

[0367] S1016: The session management network element sends a first request to the first access network device based on the second information. Correspondingly, the first access network device receives the first request from the session management network element.

[0368] Understandably, the specific processes of S1014 to S1016 are similar to those of S715 to S717 above, and you can refer to the corresponding descriptions in S715 to S717.

[0369] It is understood that the actions of the first access network device, the second access network device, the session management network element, or the mobility management network element in the above steps can be executed by the processor 401 in the communication device 40 shown in FIG4 calling the application code stored in the memory 403, and this application does not impose any restrictions on this.

[0370] The various embodiments mentioned above in this application can be combined without contradiction, and no limitation is imposed.

[0371] The above mainly describes the solution provided in this application from the perspective of interaction between various network elements. Correspondingly, this application also provides a communication device, which can be the first access network device in the above method embodiments, or a device containing the first access network device, or a component usable in the first access network device; or, the communication device can be the session management network element in the above method embodiments, or a device containing the session management network element, or a component usable in the session management network element; or, the communication device can be the mobility management network element in the above method embodiments, or a device containing the mobility management network element, or a component usable in the mobility management network element. It is understood that the above-mentioned first access network device, session management network element, or mobility management network element, etc., include hardware structures and / or software modules corresponding to the execution of each function in order to achieve the above functions. Those skilled in the art should readily recognize that, in conjunction with the unit and algorithm operations of the various examples described in the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Skilled professionals may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0372] This application can divide the first access network device, session management network element, or mobility management network element into functional modules based on the above method examples. For example, each function can be divided into its own functional modules, or two or more functions can be integrated into one processing module. The integrated modules can be implemented in hardware or as software functional modules. It is understood that the module division in this application is illustrative and only represents one logical functional division; other division methods may be used in actual implementation.

[0373] For example, when the functional modules are integrated, Figure 11 shows a schematic diagram of a communication device 110. The communication device 110 includes an interface module 1101 and a processing module 1102. The interface module 1101, also called an interface unit, is used to perform transmit and receive operations; for example, it can be an interface circuit, transceiver, or communication interface. The processing module 1102, also called a processing unit, is used to perform operations other than transmit and receive operations; for example, it can be a processing circuit or a processor.

[0374] In some embodiments, the communication device 110 may further include a storage module (not shown in FIG11) for storing program instructions and data.

[0375] In some embodiments, the communication device 110 may further include an AI module (not shown in FIG11) for implementing AI-related functions. The AI ​​module can implement AI functions through software, hardware, or a combination of software and hardware. For example, the AI ​​module includes an RIC module. Optionally, the AI ​​module and the storage module are integrated into one module, or the AI ​​module and the processing module 1102 are integrated into one module.

[0376] For example, the communication device 110 is used to implement the functions of a session management network element. The communication device 110 is, for example, the session management network element described in the embodiment shown in FIG5, the embodiment shown in FIG6A, or the embodiment shown in FIG7.

[0377] In one possible implementation, interface module 1101 is used to receive first information from the first access network device. For example, interface module 1101 can be used to execute S501a. Processing module 1102 is used to obtain the identifier or address information of the second access network device. For example, processing module 1102 can be used to execute S502. Processing module 1102 is also used to save the identifier or address information of the second access network device when the first session is deactivated based on the first information. For example, processing module 1102 can also be used to execute S503.

[0378] Another possible implementation is that processing module 1102 is used to determine that the first session is a local session. For example, processing module 1102 can be used to execute S501b. Processing module 1102 is used to obtain the identifier or address information of the access network device. For example, processing module 1102 can be used to execute S502. Processing module 1102 is also used to save the identifier or address information of the access network device when the first session is deactivated. For example, processing module 1102 can also be used to execute S503.

[0379] When used to implement the functions of the session management network element, other functions that the communication device 110 can implement can be referred to the embodiments shown in FIG5, FIG6A, or FIG7, and will not be elaborated further.

[0380] Alternatively, by way of example, the communication device 110 is used to implement the functions of the first access network device. The communication device 110 is, for example, the first access network device described in the embodiment shown in FIG5, the embodiment shown in FIG6A, the embodiment shown in FIG6B, or the embodiment shown in FIG7.

[0381] The processing module 1102 is used to determine that the terminal's first session is a local session. For example, the processing module 1102 can be used to execute S601.

[0382] Interface module 1101 is used to send third-party information to mobility management network elements. For example, interface module 1101 can be used to execute S602.

[0383] When used to implement the functions of the first access network device, other functions that the communication device 110 can implement can be referred to the relevant descriptions of the embodiments shown in FIG5, FIG6A, FIG6B, or FIG7, which will not be elaborated further.

[0384] Alternatively, by way of example, the communication device 110 is used to implement the functions of a mobility management network element. The communication device 110 is, for example, the mobility management network element described in the embodiment shown in FIG6B or the embodiment shown in FIG7.

[0385] The interface module 1101 is used to receive third information from the first access network device. For example, the interface module 1101 can be used to execute S602.

[0386] Processing module 1102 is used to determine, based on third information, not to trigger the release of the terminal's communication connection. For example, processing module 1102 can be used to execute S603.

[0387] When used to implement the functions of a mobility management network element, other functions that the communication device 110 can implement can be referred to the relevant descriptions of the embodiments shown in FIG6B or FIG7, which will not be elaborated further.

[0388] Alternatively, by way of example, the communication device 110 is used to implement the functions of a session management network element. The communication device 110 is, for example, the session management network element described in the embodiment shown in FIG8, the embodiment shown in FIG9, or the embodiment shown in FIG10.

[0389] The interface module 1101 is used to send first information to the first access network device. For example, the interface module 1101 can be used to execute S801.

[0390] Processing module 1102 is used to obtain the identifier or address information of the second access network device. For example, processing module 1102 can be used to execute S802.

[0391] The processing module 1102 is also used to save the identifier or address information of the second access network device when the first session is deactivated. For example, the processing module 1102 can also be used to execute S803.

[0392] When used to implement the functions of the session management network element, other functions that the communication device 110 can implement can be referred to the relevant descriptions of the embodiments shown in FIG8, FIG9, or FIG10, which will not be elaborated further.

[0393] Alternatively, by way of example, the communication device 110 is used to implement the functions of the first access network device. The communication device 110 is, for example, the first access network device described in the embodiment shown in FIG8, the embodiment shown in FIG9, or the embodiment shown in FIG10.

[0394] The interface module 1101 is used to receive first information from the session management network element. For example, the interface module 1101 can be used to execute S801.

[0395] The processing module 1102 is used to determine, based on the first information, that the terminal does not enter the connection management idle state, or to determine that the terminal can enter the radio resource control inactive state.

[0396] When used to implement the functions of the first access network device, for other functions that the communication device 110 can implement, please refer to the relevant descriptions of the embodiments shown in FIG8, FIG9, or FIG10, which will not be repeated here.

[0397] In a simplified embodiment, those skilled in the art will recognize that the communication device 110 can take the form shown in FIG4. For example, the processor 401 in FIG4 can invoke computer execution instructions stored in memory 403 to cause the communication device 110 to perform the methods described in the above embodiments.

[0398] For example, the functions / implementation processes of the interface module 1101 and processing module 1102 in Figure 11 can be implemented by the processor 401 in Figure 4 calling computer execution instructions stored in memory 403. Alternatively, the functions / implementation processes of the processing module 1102 in Figure 11 can be implemented by the processor 401 in Figure 4 calling computer execution instructions stored in memory 403, and the functions / implementation processes of the interface module 1101 in Figure 11 can be implemented by the transceiver 402 in Figure 4.

[0399] It is understood that one or more of the above modules or units can be implemented by software, hardware, or a combination of both. When any of the above modules or units are implemented by software, the software exists as computer program instructions and is stored in memory. The processor can be used to execute the program instructions and implement the above method flow. The processor can be built into a system-on-a-chip (SoC) or an application-specific integrated circuit (ASIC), or it can be a stand-alone semiconductor chip. In addition to the core that executes software instructions for computation or processing, the processor may further include necessary hardware accelerators, such as field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), or logic circuits that implement dedicated logic operations.

[0400] When the above modules or units are implemented in hardware, the hardware can be any one or any combination of a CPU, microprocessor, digital signal processing (DSP) chip, microcontroller unit (MCU), artificial intelligence processor, ASIC, SoC, FPGA, PLD, application-specific digital circuit, hardware accelerator, or non-integrated discrete device, which can run the necessary software or perform the above method flow independently of software.

[0401] Optionally, this application also provides a chip system, including: at least one processor and an interface, wherein the at least one processor is coupled to a memory via the interface, and when the at least one processor executes a computer program or instructions in the memory, the method in any of the above method embodiments is executed. In one possible implementation, the chip system further includes a memory. Optionally, the chip system may be composed of chips or may include chips and other discrete devices; this application does not specifically limit this.

[0402] Optionally, this application also provides a computer-readable storage medium. All or part of the processes in the above method embodiments can be implemented by a computer program instructing related hardware. This program can be stored in the aforementioned computer-readable storage medium. When executed, the program can include the processes described in the above method embodiments. The computer-readable storage medium can be an internal storage unit of the communication device in any of the foregoing embodiments, such as the hard disk or memory of the communication device. The aforementioned computer-readable storage medium can also be an external storage device of the communication device, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the communication device. Further, the aforementioned computer-readable storage medium can include both internal storage units and external storage devices of the communication device. The aforementioned computer-readable storage medium is used to store the aforementioned computer program and other programs and data required by the communication device. The aforementioned computer-readable storage medium can also be used to temporarily store data that has been output or will be output.

[0403] Optionally, this application also provides a computer program product. All or part of the processes in the above method embodiments can be executed by a computer program instructing related hardware. This program can be stored in the above computer program product, and when executed, it can include the processes described in the above method embodiments.

[0404] Optionally, this application also provides computer instructions. All or part of the processes in the above method embodiments can be executed by computer instructions instructing related hardware (such as a computer, processor, access network equipment, session management network element, or mobility management network element). The program can be stored in the aforementioned computer-readable storage medium or the aforementioned computer program product.

[0405] Optionally, this application also provides a communication system, including at least one of the following: a first access network device in the method shown in FIG. 6A, a session management network element in the method shown in FIG. 6A, or a mobility management network element in the method shown in FIG. 6B.

[0406] Optionally, this application also provides a communication system, including at least one of the first access network device, mobility management network element, or session management network element in the method shown in FIG9.

[0407] Through the above description of the embodiments, those skilled in the art can clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0408] It is understood that the message names between network elements or the names of parameters in the messages in the above embodiments of this application are just examples, and other names may be used in the specific implementation. This application does not make any specific limitations on this.

[0409] It is understood that in this application, " / " can indicate that the objects before and after it are in an "or" relationship. For example, A / B can mean A or B. "And / or" can be used to describe three relationships between the related objects. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. Here, A and B can be singular or plural. Furthermore, expressions like "at least one of A, B, and C" or "at least one of A, B, or C" are generally used to indicate any of the following: A exists alone; B exists alone; C exists alone; A and B exist simultaneously; A and C exist simultaneously; B and C exist simultaneously; A, B, and C exist simultaneously. The above examples using three elements (A, B, and C) illustrate the optional entries for this item. When the expression contains more elements, its meaning can be obtained according to the aforementioned rules.

[0410] To facilitate the description of the technical solutions of this application, the terms "first" and "second" may be used to distinguish technical features with the same or similar functions. The terms "first" and "second" do not limit the number or execution order, nor do they imply that they are necessarily different. In this application, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design scheme described as "exemplary" or "for example" should not be construed as being more preferred or advantageous than other embodiments or design schemes. The use of "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner for ease of understanding.

[0411] It is understood that the term "embodiment" used throughout the specification means that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of this application. Therefore, various embodiments throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It is understood that in the various embodiments of this application, the sequence number of each process does not imply a sequential 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 this application.

[0412] It is understood that in this application, "when," "under the circumstances," "if," and "if" all refer to the corresponding processing that will be carried out under certain objective circumstances, and are not time-limited, nor do they require that there must be a judgment action when implemented, nor do they imply any other limitations.

[0413] In this application, "simultaneously" can be understood as at the same point in time, within a period of time, or within the same cycle.

[0414] It is understood that some optional features in this application can be implemented independently in certain scenarios without relying on other features, such as the current solution upon which they are based, to solve the corresponding technical problems and achieve the corresponding effects. Alternatively, they can be combined with other features as needed in certain scenarios. Accordingly, the apparatus provided in this application can also implement these features or functions.

[0415] It is understood that the same step or step with the same function or technical feature in this application can be referenced and learned from each other in different embodiments.

[0416] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0417] The units described as separate components may or may not be physically separate. A component shown as a unit can be one or more physical units; that is, it can be located in one place or distributed in multiple different locations. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0418] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0419] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions 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

A session management method, characterized in that, Applied to a session management network element, wherein the session management network element manages the first session of a terminal, the method includes: The system receives first information from a first access network device, wherein the first information instructs the access network device to manage the mobility of the terminal, or the first information instructs the access network device to save its identifier or address information when the first session is deactivated, or the first information instructs the user plane information to be released only when the first session is deactivated, or the first information is used to establish the first session and does not carry information about the mobility management network element. Obtain the identifier or address information of the second access network device, which is the access network device accessed by the terminal; Based on the first information, the identifier or address information of the second access network device is saved when the first session is deactivated. The method according to claim 1, characterized in that, The method further includes: Receive second information from a user plane network element, the second information indicating that data from the first session has been received; Based on the second information, a first request is sent to the second access network device, the first request being used to request activation of the first session. The method according to claim 2, characterized in that, The method further includes: If the first session activation fails, a second request is sent to the mobility management network element, the second request being used to request the access network device to which the terminal is connected. The method according to any one of claims 1-3 is characterized in that, The first information instructs the access network device to manage the mobility of the terminal; The receiving of first information from the first access network device includes: A first message is received from the first access network device. The first message includes the first information and is used to request the establishment of the first session. The method according to any one of claims 1-3 is characterized in that, The first information indicates that when the first session is deactivated, the identifier or address information of the access network device is saved, or the first information indicates that when the first session is deactivated, only the user plane information is released; The receiving of first information from the first access network device includes: A second message is received from the first access network device, the second message including the first information, the second message being used to request deactivation of the first session, the first access network device being the same as the second access network device. The method according to claim 5, characterized in that, The second message is an update session management context request message. The method according to any one of claims 1-3 is characterized in that, The first information indicates that when the first session is deactivated, the identifier or address information of the access network device is saved, or the first information indicates that when the first session is deactivated, only the user plane information is released; The method further includes: Send a session resource release message to the first access network device; The receiving of first information from the first access network device includes: Receive a session resource release response message from the first access network device, the session resource release response message including the first information, the first access network device being the same as the second access network device. The method according to any one of claims 1-7 is characterized in that, The first session is a local session, which is a session that accesses or routes to the local core network. A session management method, characterized in that, Applied to a first access network device, the method includes: The terminal's first session is determined to be a local session, which is a session that accesses or routes to the local core network; Send a third message to the mobility management network element, the third message indicating that the communication connection of the terminal should be maintained, or the third message indicating that the communication connection of the terminal should not be released, or the third message indicating that the terminal should not enter the connection management idle state. The method according to claim 9, characterized in that, The method further includes: Send a first message to the session management network element, wherein the first message instructs the access network device to manage the mobility of the terminal, or the first message instructs the access network device to save its identifier or address information when the first session is deactivated, or the first message instructs the user plane information to be released only when the first session is deactivated, or the first message is used to establish the first session and does not carry information about the mobility management network element. The method according to claim 10, characterized in that, The first information instructs the access network device to manage the mobility of the terminal; Sending the first information to the session management network element includes: A first message is sent to the session management network element. The first message includes the first information and is used to request the establishment of the first session. The method according to claim 10, characterized in that, The first information indicates that the identifier or address information of the access network device is saved when the first session is deactivated, or the first information indicates that only the user plane information is released when the first session is deactivated; Sending the first information to the session management network element includes: A second message is sent to the session management network element. The second message includes the first information and is used to request the deactivation of the first session. The method according to claim 12, characterized in that, The second message is an update session management context request message. The method according to claim 10, characterized in that, The first information indicates that the identifier or address information of the access network device is saved when the first session is deactivated, or the first information indicates that only the user plane information is released when the first session is deactivated; The method further includes: Receive a session resource release message from the session management network element; Sending the first information to the session management network element includes: Send a session resource release response message to the session management network element, the session resource release response message including the first information. The method according to any one of claims 9-14 is characterized in that, The first access network device stores at least one of the following local network information: local network slice information, or local data network name information; The determination that the first session of the terminal is a local session includes: The first session is determined to be a local session based on the local network information and the attribute information corresponding to the first session. The attribute information corresponding to the first session includes at least one of slice information or data network name information. A session management method, characterized in that, Applied to a session management network element, wherein the session management network element manages the first session of a terminal, the method includes: Send first information to a first access network device, the first information being used to instruct the access network device to manage the mobility of the terminal, or the first information being used to request the access network device to manage the mobility of the terminal; Obtain the identifier or address information of the second access network device, which is the access network device accessed by the terminal; When the first session is deactivated, the identifier or address information of the second access network device is saved. The method according to claim 16, characterized in that, The method further includes: Receive second information from a user plane network element, the second information indicating that data from the first session has been received; Based on the second information, a first request is sent to the second access network device, the first request being used to request activation of the first session. The method according to claim 17, characterized in that, The method further includes: If the first session activation fails, a second request is sent to the mobility management network element, the second request being used to request the access network device to which the terminal is connected. The method according to any one of claims 16-18 is characterized in that, The method further includes: Receive third information from the first access network device, the third information being used to confirm that the access network device manages the mobility of the terminal; Saving the identifier or address information of the second access network device when the first session is deactivated includes: Based on the third information, the identifier or address information of the second access network device is saved when the first session is deactivated. The method according to any one of claims 16-19 is characterized in that, The method further includes: Receive first policy information, which instructs the first session to maintain control plane connection in the deactivated state; Sending the first information to the first access network device includes: The first information is sent to the first access network device according to the first policy information. The method according to any one of claims 16-19 is characterized in that, Sending the first information to the first access network device includes: When the first session is a local session, the first information is sent to the first access network device. A local session is a session that accesses or routes to the local core network. A session management method, characterized in that, Applied to a first access network device, the method includes: Receive first information from a session management network element, wherein the first information is used to indicate the mobility of the access network device management terminal, or the first information is used to request the mobility of the access network device management terminal; Based on the first information, it is determined that the terminal does not enter the connection management idle state, or that the terminal can enter the radio resource control inactive state. The method according to claim 22, characterized in that, The method further includes: When the terminal switches to the second access network device, the identifier or address information of the second access network device is sent to the session management network element. The method according to claim 22 or 23 is characterized in that, The session management network element manages the terminal's first session, which is a local session, and a local session is a session that accesses or is routed to the local core network. A communication device, characterized in that, It includes units or modules for performing the method as described in any one of claims 1 to 8, or units or modules for performing the method as described in any one of claims 9 to 15, or units or modules for performing the method as described in any one of claims 16 to 21, or units or modules for performing the method as described in any one of claims 22 to 24. A communication device, characterized in that, include: A processor coupled to a memory for storing a program or instructions which, when executed by the processor, cause the apparatus to perform the method as claimed in any one of claims 1 to 8, or the method as claimed in any one of claims 9 to 15, or the method as claimed in any one of claims 16 to 21, or the method as claimed in any one of claims 22 to 24. A computer-readable storage medium having a computer program or instructions stored thereon, characterized in that, When the computer program or instructions are executed, they cause the computer to perform the method as described in any one of claims 1 to 8, or the method as described in any one of claims 9 to 15, or the method as described in any one of claims 16 to 21, or the method as described in any one of claims 22 to 24. A computer program product, comprising computer program code, characterized in that, When the computer program code is run on a computer, it causes the computer to implement the method of any one of claims 1 to 8, or the method of any one of claims 9 to 15, or the method of any one of claims 16 to 21, or the method of any one of claims 22 to 24.

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