RU2793337C1 - Session processing method, communication device and communication system - Google Patents

Abstract

FIELD: communication; session processing method; a communication device; a communication system.

SUBSTANCE: according to the session processing method, a request message from the intermediate session management function is received (S310) by the session management anchor function, which contains the session identifier. The intermediate session control function is a session control function connected to the access and mobility control function and is intended to serve the UE when the UE moves outside the coverage area of the anchor session control function. In response to determining that the session corresponding to the session ID is a data local area network session, the session is disconnected (S311) by the session management anchor function. The coverage area of the data local area network corresponding to the session of the data local area network is in the coverage area of the session management anchor function.

EFFECT: correct communication in the presence of two session management functions (SMF).

14 cl, 17 dwg

Description

[0001] The present application claims the priority of Chinese Patent Application No. 201910262879.X, filed with the China Patent Office on April 2, 2019, entitled "SESSION HANDLING METHOD, COMMUNICATIONS APPARATUS, AND COMMUNICATIONS SYSTEM", which is incorporated herein in its entirety by reference .

The field of technology to which the invention belongs

[0002] The present application relates to the field of communication and, in particular, to a session processing method, a communication device, and a communication system.

State of the art

[0003] A local area data network (LADN) is a network covering a specific local area, such as a network covering a place such as an enterprise, campus, airport, train station, shopping mall, or stadium. The user equipment (user equipment (UE)) can access the LADN via a packet data unit (PDU) session for the LADN only when the UE is in the service area of the LADN.

[0004] The UE accesses the local user plane function (UPF) via the radio access network for direct access to the local network. The UE can receive frequently used data from the LADN without access to a network other than the LADN. This reduces the delay in receiving data and reduces the occupied bandwidth because the UE often requests data from a network other than LADN.

[0005] LADN covers only a specific service area. The LADN information is configured in the access and mobility management function (AMF). The AMF is only configured with LADN information in an AMF service area, such as an LADN service area. When the UE moves from the LADN to another network, the UE may comply with the new AMF. In addition, in the current network architecture, two SMFs may be involved based on the requirements of the UE in a network handover process. For example, the inserted intermediate SMF provides an intermediate UPF for a UE that cannot access the anchor UPF corresponding to the anchor SMF. Thus, the UE can access the anchor UPF. However, when the intermediate SMF is not configured with LADN information, the intermediate SMF cannot identify the received LADN session-related indication information and cannot send the LADN-related indication information to the anchor SMF, affecting normal session operation of the anchor SMF.

[0006] Therefore, when two SMFs are involved in a session processing procedure, the question of how to ensure that the anchor SMF properly initiates the session becomes an urgent problem to be solved.

The essence of the invention

[0007] The present application provides a session handling method, a communication device, and a communication system to solve the problem that a session cannot be properly processed when there are two session management functions (SMFs).

[0008] According to a first aspect, a session processing method is provided, including: receiving an intermediate session management function (SMF) of a request message sent by an access and mobility management function (AMF), the request message including a session identifier, and the intermediate The SMF is the SMF selected by the Access and Mobility Management Function (AMF) when the user equipment (UE) moves outside the coverage area of the anchor SMF; and when the session corresponding to the session ID is a local data area network (LADN) session, rejecting the intermediate SMF of the session corresponding to the session ID.

[0009] According to the session handling method in this embodiment of the present application, when the intermediate SMF learns that the requested session is an LADN session, the intermediate SMF rejects the session and the UE can no longer access the LADN service after moving outside the anchor SMF's service area. This avoids wasting LADN service resources.

[0010] With reference to the first aspect, in some embodiments of the first aspect, the method further includes: determining the intermediate SMF based on the session context sent by the anchor SMF that the session is an LADN session, wherein the session context includes first indication information, used to indicate that the session is an LADN session; or determining the intermediate SMF based on the second indication information sent by the Access and Mobility Management Function (AMF) that the session is an LADN session, the second indication information being used to indicate that the UE is outside the LADN service area.

[0011] With reference to the first aspect, in some embodiments of the first aspect, the method further includes: sending an intermediate SMF of a first message to the AMF, wherein the first message includes cause information.

[0012] With reference to the first aspect, in some embodiments of the first aspect, the reason information includes: reject insertion of an intermediate SMF, and an intermediate user plane function (UPF) is rejected for the LADN session.

[0013] With reference to the first aspect, in some embodiments of the first aspect, the LADN service area corresponding to the LADN session is within the coverage area of the anchor SMF.

[0014] According to a second aspect, a session processing method is provided, including: sending an Access and Mobility Management Function (AMF) a request message to an intermediate SMF, wherein the request message includes a session identifier, and the intermediate SMF is an SMF selected an access and mobility management function (AMF) when the UE moves outside the coverage area of the anchor SMF; and receiving the access and mobility management function (AMF) of the first message sent to the intermediate SMF, the first message including cause information.

[0015] According to the session handling method in this embodiment of the present application, when the anchor SMF learns that the requested session is an LADN session, the anchor SMF rejects the session and the UE can no longer access the LADN service after moving out of the anchor SMF's service area. This avoids wasting LADN service resources.

[0016] With reference to the second aspect, in some embodiments of the second aspect, the reason information includes the following: insertion of an intermediate SMF and an intermediate user plane function (UPF) is rejected for the LADN session.

[0017] With reference to the second aspect, in some embodiments of the second aspect, the method further includes: sending cause information via AMF to a radio access network (RAN).

[0018] With reference to the second aspect, in some embodiments of the second aspect, the method further includes: sending an access and mobility management function (AMF) a session release request message to the anchor SMF, wherein the session release request message is used to request the anchor SMF. SMF disconnect LADN session.

[0019] With reference to the second aspect, in some embodiments of the second aspect, the LADN to which the LADN session belongs is in the coverage area of the anchor SMF.

[0020] According to a third aspect, a session processing method is provided, including: receiving an anchor SMF of a request message sent to an intermediate SMF, wherein the request message includes a session identifier, and the intermediate SMF is an SMF selected by the access and mobility control function (AMF) when the UE moves outside the service area of the anchor SMF; and when the session corresponding to the session ID is an LADN session, rejecting the anchor SMF of the session corresponding to the session ID, the LADN session being the session served by the anchor SMF.

[0021] With reference to a third aspect, in some embodiments of the third aspect, a request message is used to request insertion of an intermediate SMF.

[0022] With reference to the third aspect, in some embodiments of the third aspect, the method further includes: determining the anchor SMF based on the session context that the current session is an LADN session; or determining the anchor SMF based on the configuration information that the current session is an LADN session, the configuration information including: The DNN corresponding to the current session is an LADN.

[0023] With reference to the third aspect, in some embodiments of the third aspect, the method further includes: sending the anchor SMF a second message to the intermediate SMF, wherein the second message includes reason information, and the reason information is used to indicate that the session cannot be engaged, or the reason information is used to instruct the intermediate SMF to reject the session engagement.

[0024] With reference to a third aspect, in some embodiments of the third aspect, rejecting the session anchor SMF corresponding to the session ID includes: releasing the session anchor SMF corresponding to the session ID; or terminating the session anchor SMF corresponding to the session ID; or rejecting the session engagement or handover anchor SMF corresponding to the session ID.

[0025] With reference to the third aspect, in some embodiments of the third aspect, the reason information includes the following: insertion of the intermediate SMF and intermediate UPF is rejected for the LADN session.

[0026] With reference to a third aspect, in some embodiments of the third aspect, the LADN service area corresponding to the LADN session is within the coverage area of the anchor SMF.

[0027] According to a fourth aspect, a session processing method is provided, including: receiving a first intermediate SMF of first indication information, wherein the first indication information is used to indicate that a data network name (DNN) corresponding to the current session is LADN, and the first the intermediate SMF is configured to control the intermediate UPF that communicates with the target base station; sending the first intermediate SMF second indication information to the anchor SMF, wherein the second indication information is used to indicate that the UE is outside the LADN service area and the anchor SMF is the anchor SMF serving the current session; and releasing the current session anchor SMF based on the second indication information.

[0028] According to the session processing method in this embodiment of the present application, the first intermediate SMF learns, based on the first indication information, that the current session is an LADN session, and can subsequently identify the LADN information for further processing of the LADN session.

[0029] With reference to the fourth aspect, in some embodiments of the fourth aspect, the method further includes: receiving a first intermediate SMF of a third message sent to the target AMF; and when the third message does not include indication information indicating that the UE is outside the LADN service area, determining the first intermediate SMF that the UE is outside the LADN service area, wherein the target AMF is the AMF to which the UE is handed over.

[0030] With reference to the fourth aspect, in some embodiments of the fourth aspect, the method further includes: receiving a first intermediate SMF of a fourth message sent to the target AMF; and when the fourth message includes: the UE is outside the LADN service area, sending the first intermediate SMF of the second indication information to the anchor SMF.

[0031] Optionally, the first indication information is sent by any of the following network elements: source AMF, target AMF, anchor SMF, or second intermediate SMF, wherein the second intermediate SMF is configured to control the intermediate UPF that communicates with the source base station.

[0032] According to a fifth aspect, a session processing method is provided, including: receiving a target AMF of a first indication information sent by a source AMF, wherein the first indication information is used to indicate that a DNN corresponding to the current session is an LADN; and when the target AMF determines that the UE is moving outside the LADN service area, sending the target AMF the second indication information to the first intermediate SMF, wherein the second indication information is used to indicate that the UE is outside the LADN service area, and the first intermediate SMF is performed with the ability to manage an intermediate UPF that communicates with the target base station.

[0033] It should be understood that after performing the AMF handoff procedure, the new AMF may not be configured with LADN information, and therefore the new AMF cannot determine if the UE is in the LADN service area.

[0034] According to the session processing method in this embodiment of the present application, the source AMF, which is used before performing the AMF handover, notifies the target AMF with LADN information, and the target AMF receives the LADN information. The target AMF may then optionally notify the SMF with information to ensure that the LADN session is handled correctly.

[0035] With reference to the fifth aspect, in some embodiments of the fifth aspect, that the target AMF determines that the UE is moving outside the LADN service area includes: when the target AMF is not configured with LADN information, determining the target AMF that The UE moves outside the LADN service area.

[0036] With reference to the fifth aspect, in some embodiments of the fifth aspect, that the target AMF determines that the UE is moving outside the LADN service area includes: when the target AMF is configured with LADN information, determining the target AMF based on the information about the LADN and the location of the UE, that the UE moves outside the LADN service area.

[0037] With reference to the fifth aspect, in some embodiments of the fifth aspect, the LADN information includes information about the LADN service area.

[0038] According to a sixth aspect, a communication device is provided, including at least one processor and a communication interface, wherein the communication interface is used to exchange information between a network device and another network device, and when program instructions are executed on at least one processor, the network device implements the intermediate SMF function in the method according to any embodiment of the first aspect.

[0039] According to a seventh aspect, a communication device is provided, including at least one processor and a communication interface, wherein the communication interface is used to exchange information between a network device and another network device, and when program instructions are executed on at least one processor, the implementation of the AMF function by the network device in the method according to any embodiment of the second aspect is provided.

[0040] According to an eighth aspect, a communication device is provided, including at least one processor and a communication interface, wherein the communication interface is used to exchange information between a network device and another network device, and when program instructions are executed on at least one processor, enabling the network device to implement the anchor SMF function in the method according to any embodiment of the third aspect.

[0041] According to a ninth aspect, a communication device is provided, including at least one processor and a communication interface, wherein the communication interface is used to exchange information between a network device and another network device, and when program instructions are executed on at least one processor, the implementation of the first intermediate SMF function by the network device in the method according to any embodiment of the fourth aspect is provided.

[0042] According to a tenth aspect, a communication system is provided, including an intermediate session management function (SMF) and an access and mobility management function (AMF), which are configured to perform the method according to the first aspect.

[0043] According to an eleventh aspect, a communication system is provided, including an anchor SMF, an intermediate SMF, and an AMF, which are configured to perform the method according to the second aspect.

[0044] According to a twelfth aspect, a communication system is provided, including an intermediate SMF and an anchor SMF, which are configured to perform the method according to the third aspect.

[0045] According to a thirteenth aspect, a communication system is provided, including a source SMF and a target SMF, which are configured to perform the method according to the fourth aspect.

[0046] According to a fourteenth aspect, a computer program product is provided, wherein the computer program product includes computer program code, and when the computer program code is executed by a communication device (e.g., a terminal device or a network device), causing the communication device to execute a method according to any one of the first through fifth aspects, or any embodiment of the first through fifth aspects.

[0047] According to a fifteenth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores program instructions, and the program instructions cause a communications device (e.g., a terminal device or a network device) to execute a method according to any of the first to fifth aspects, or any embodiment with first through fifth aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] FIG. 1 is a schematic diagram of a local area network system architecture;

[0049] Figure 2 is a schematic diagram of the network architecture of a 5G system;

[0050] FIG. 3 is a flowchart of a session processing method according to one embodiment of the present application;

[0051] FIG. 4 is a flowchart of another session processing method according to one embodiment of the present application;

[0052] FIG. 5 is a flowchart of yet another session processing method according to one embodiment of the present application;

[0053] FIG. 6 is a flowchart of yet another session processing method according to one embodiment of the present application;

[0054] FIG. 7 is a flowchart of yet another session processing method according to one embodiment of the present application;

[0055] FIGS. 8A and 8B show a flowchart of an additional session processing method according to one embodiment of the present application;

[0056] FIG. 9 is a flowchart of yet another session processing method according to one embodiment of the present application;

[0057] FIG. 10 is a flowchart of yet another session processing method according to one embodiment of the present application;

[0058] FIG. 11 is a schematic structural diagram of a communication device according to one embodiment of the present application;

[0059] FIG. 12 is a schematic structural diagram of a communication device according to another embodiment of the present application;

[0060] Fig. 13 is a schematic structural diagram of a communication device according to another embodiment of the present application;

[0061] Fig. 14 is a schematic structural diagram of a communication device according to another embodiment of the present application;

[0062] Fig. 15 is a schematic structural diagram of a communication device according to another embodiment of the present application; And

[0063] FIG. 16 is a schematic structural diagram of a communication device according to a further embodiment of the present application.

Description of Embodiments

[0064] The following describes the technical solutions of the present application with reference to the accompanying drawings.

[0065] The technical solutions in the embodiments of the present application can be applied to various communication systems, such as global system for mobile communications (GSM), code division multiple access (CDMA)) , wideband code division multiple access (WCDMA) system, general packet radio service (GPRS), long term evolution (LTE) system, duplex communication system with frequency division duplex (FDD) LTE, time division duplex (TDD) LTE, universal mobile telecommunication system (UMTS), worldwide interconnection communication system for microwave access ( worldwide interoperability for microwave access (WiMAX) and the future 5th generation (5G) or new radio (NR) system. Each of the above systems may include a Session Control Network Element and an Access and Mobility Network Element. In different systems, a network element having a session management function and a network element having an access and mobility control function may correspond to different names. For example, in a 5G system, the session control network element may be referred to as SMF, and the access and mobility control network element may be referred to as AMF.

[0066] The terminal device in the embodiments of the present application may be a user equipment (user equipment (UE)), a terminal device, an access terminal, a subscriber device, a subscriber station, a mobile station, a mobile station, a remote station, a remote station. terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user device. Alternatively, the terminal device may be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA )), a portable device with a wireless function, a computing device, another data processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in the future 5G network, a terminal device in the future public enhanced land mobile network (public land mobile network (PLMN)) etc. Alternatively, the terminal device or user equipment may be a chip. In embodiments of the present application, this is not limited.

[0067] The technical solutions presented in the embodiments of the present application are applicable to the session processing scenario intended for LADN. When the user equipment enters the LADN service area, a session is established to access the LADN service. The session may be an LADN session, and the LADN session is a session used to perform data transmission in the LADN service area for the UE. An anchor-SMF (anchor-SMF (A-SMF)) can manage a service such as session establishment, session release, or session termination in the LADN. In the current network system, the anchor SMF cannot independently determine the location information of the UE and must subscribe to the location information of the UE from the access and mobility management function (AMF). The AMF may detect whether the UE is in the LADN service area and send indication information indicating whether the UE is in the LADN service area to the anchor SMF. For example, when the AMF detects that the UE is moving outside the current LADN service area, the AMF may send indication information to the anchor SMF indicating that the UE is outside the LADN service area or the UE is moving outside the LADN service area. For example, the indication information may be "OUT" indicated in the LADN UE presence notification message so that the anchor SMF knows that the UE is moving outside the current LADN's coverage area. The anchor SMF then releases or terminates the session and the UE can no longer access the service provided by the LADN.

[0068] When the UE moves outside the coverage area of the anchor SMF, an AMF handoff may be performed. In other words, the UE must be handed over from the source AMF to the target AMF. The source AMF is the AMF used before the UE moves, and the target AMF is the new AMF to which the UE is handed over after the UE moves. The source AMF is configured with LADN information, but the target AMF may not be configured with LADN information. The LADN information may be, for example, a network name corresponding to the LADN or information about the LADN service area. Therefore, the target AMF may not send indication information indicating whether the UE is moving outside the LADN service area to the anchor SMF. In addition, since the location of the UE changes during movement, the UE cannot directly access through the RAN to the anchor UPF (anchor-UPF (A-UPF)) managed by the anchor SMF. In this case, an intermediate SMF (intermediate-SMF (I-SMF)) must be entered. The intermediate SMF may select and insert an intermediate UPF ((intermediate-UPF (I-UPF)) for the RAN connection and an anchor UPF. It should be understood that when two SMFs (anchor SMF and an intermediate SMF) are involved in a network system), the anchor SMF may be is configured with information about which DNN corresponds to the LADN and can perform the associated LADN session operation, such as establishing, disconnecting, or terminating the LADN session.However, an intermediate SMF in the current network system cannot usually be configured with information about which DNN corresponds LADN As a result, when an intermediate SMF exists, a problem may occur in LADN session processing.For example, when a UE is handed over to a new AMF after the UE moves, because the new AMF is not configured with LADN information, the AMF may not send pointing information to the intermediate SMF, indicating that the UE is moving outside the LADN In this case, because the intermediate SMF is not configured with which DNN the LADN is, the intermediate SMF cannot know that the current session is an LADN session and cannot send a notification message to the anchor SMF indicating that the UE is moving outside the LADN. Then the anchor SMF cannot know that the UE is moving out of the LADN service area and cannot initiate a session termination or disconnect operation. Therefore, the UE still accesses the LADN after moving outside the LADN service area. This is contrary to the LADN service access principle.

[0069] FIG. 1 is a schematic diagram of a local area network architecture according to one embodiment of the present application.

[0070] LADN is a network that covers a specific local area. The UE accesses the local UPF through the RAN for direct access to the LADN. The local UPF could be, for example, the UPF on the campus corporate network, or the UPF next to the LADN. Direct access to the LADN by the UE can reduce the delay in application access and reduce the occupied transmission bandwidth of the backbone network. LADN can be applied to, for example, a stadium, campus, business, or shopping mall. In the stadium, LADN is used to provide a live broadcast of virtual reality (virtual reality (VR)). On campus, LADN is used to provide intra-campus communications to allow UEs to access learning resources on campus. In the enterprise, LADN is used to provide communication for production control. The mall uses LADN to provide services such as discounts on local purchases and real-time position and navigation.

[0071] The LADN information may include information about the name and corresponding LADN service area, and the like. The LADN information can be configured in the AMF. AMF can only be configured with LADN information in the AMF service area. For example, the AMF in Beijing may not be configured with information about the LADN in Shenzhen. The AMF may detect, based on the LADN service area and the location of the UE, whether the UE is in the LADN service area. When the UE moves outside the current LADN service area, the AMF sends indication information to the A-SMF indicating that the UE is moving outside the LADN service area. The A-SMF then disconnects or terminates the LADN session established by the UE. In other words, the UE is no longer allowed to access the LADN service.

[0072] FIG. 2 is a schematic diagram of a network architecture of a 5G system to which embodiments of the present application apply.

[0073] In a 5G system, a UE can perform a RAN handoff based on an Xn interface, wherein the Xn interface is an interface between a source access network (source-RAN (S-RAN)) and a target access network (target-RAN (T-RAN) ). The network elements in the 5G system that are used in the session processing method provided in the embodiments of the present application include RAN, source AMF (source-AMF (S-AMF)), target AMF (target-AMF (A-AMF)) , I-SMF, A-SMF, UPF, etc. For ease of understanding, some of the network elements in the 5G system that are present in the embodiments of the present application are briefly described below.

[0074] RAN: this is an access network. In embodiments of the present application, the access network may include an S-RAN access network in a source network and a T-RAN access network in a target network.

[0075] AMF: This is an access and mobility management function. The AMF mainly accesses the non-access stratum (NAS) signaling of the UE through N1 and accesses the RAN signaling through N2. The NAS signaling may include, for example, session management (SM) signaling. AMF can be used for UE registration procedure, SM signaling forwarding and mobility management.

[0076] SMF: This is a session management function. As described above, the SMF in the embodiments of the present application includes I-SMF and A-SMF. A-SMF is the SMF serving the session. The A-SMF has a policy and charging control (PCC) interface and a unified data management (UDM) interface, and can be configured to perform UE address allocation over the internet protocol ( IP)) and the like. The I-SMF may be configured to control an intermediate user plane function (I-UPF) that the A-SMF cannot control. The I-UPF may be an intermediate UPF between the RAN and the session anchor A-UPF. The I-SMF can be inserted, changed or removed depending on the requirements. For example, after the UE moves outside the service area of the A-SMF, the RAN with which the UE is connected may not be directly connected to the A-UPF controlled by the A-SMF. In this case, a new I-SMF may be inserted and the I-SMF may select and insert the I-UPF. The UE may then first access the I-UPF via the RAN and may be connected to the A-UPF via the I-UPF.

[0077] UPF: This is a user plane function that is mainly used for data packet forwarding, quality of service (QoS) flow binding, and the like.

[0078] Embodiments of the present application may be applicable to a process in which the UE moves outside the LADN service area. The session processing method provided in the embodiments of the present application will be described below with reference to FIG.

[0079] FIG. 3 is a flowchart of a session processing method according to one embodiment of the present application.

[0080] For ease of understanding, the scenario to which this embodiment is applied is first briefly described.

[0081] This embodiment is applicable to the process in which the UE is moving. Specifically, the UE establishes an LADN session in the LADN service area. However, the LADN session is subsequently terminated and the UE moves out of the LADN service area. In the above case, the UE initiates a service request outside the LADN service area to request the activation of the LADN session. In this embodiment, it is specified that the insertion of an intermediate SMF and an intermediate UPF to continue accessing the LADN service is not allowed by the LADN session. Thus, handling of the LADN session during the move is simplified. For example, in one implementation, the LADN service area can be assumed to be a subset of the anchor SMF's service area. In other words, the LADN service area is included in the anchor SMF service area. When the UE moves outside the anchor SMF's coverage area, the UE necessarily moves outside the LADN's coverage area. It should be understood that in this embodiment, AMF handoff may or may not be performed. The specific procedure of the embodiment in FIG. 3 is as follows.

[0082] S301: The UE initiates a service request to the RAN.

[0083] Optionally, the UE initiates a service request procedure in the RAN. Specifically, the UE may send registration request information to the RAN. The registration request information includes a session ID to be enabled. The registration request information may include a list of session IDs to be enabled. The DNN corresponding to the session identifier may be a LADN DNN or may be a non-LADN DNN. In this embodiment, a case is described in which the DNN corresponding to the session ID is a LADN DNN.

[0084] It is to be understood that the following descriptions have the same meaning: DNN corresponding to a session ID or DNN corresponding to a session is LADN DNN or DNN corresponding to a session ID or DNN corresponding to a session is LADN or the corresponding session is a session LADN or session corresponds to LADN or DNN corresponding to session ID or DNN corresponding to session is LADN. The above descriptions are used to indicate that the session is an LADN session and are applicable to all parts of this application. Here is a general description, and the details below are not described again.

[0085] S302: The RAN sends a service request message to the AMF.

[0086] Optionally, the DNN corresponding to the session ID included in the service request message sent by the RAN to the AMF is a LADN.

[0087] Optionally, a service request message is used to request the activation of the current session. In one embodiment, the request message may be used to request a session management (SM) context.

[0088] S303: AMF selects an intermediate SMF.

[0089] It should be understood that after the UE moves outside the coverage area of the anchor SMF, the AMF selects and inserts the intermediate SMF. An intermediate SMF may select an intermediate UPF to connect to an anchor UPF. For a process where an AMF selects an intermediate SMF, refer to the existing procedure. Details are not described here.

[0090] Optionally, the AMF may be the original AMF used before the handover is performed, or it may be the target AMF used after the AMF handover procedure is performed.

[0091] S304: The AMF sends a request message to the intermediate SMF.

[0092] The AMF sends an intermediate SMF request message. The request message is used to request the creation of a session context and includes a session identifier. The session identifier may be a session identifier of the PDU, or may be another identifier that is used by the intermediate SMF to uniquely identify the session, such as a URI (uniform resource identifier) or an SM context identifier. This application is not limited.

[0093] It should be understood that when an AMF handover is not performed, the AMF is configured with LADN information. Based on the configured LADN information (including the LADN DNN, the corresponding service area, etc.) and the UE location information, the AMF may determine whether the UE moves outside the LADN service area. In this case, the session creation request message sent by the AMF to the intermediate SMF may include indication information indicating that the UE is outside the LADN service area, namely the second indication information.

[0094] Optionally, when an AMF handoff is performed, the AMF is the new AMF used after the handover. In this case, AMF cannot be configured with LADN information. The session creation request sent by the AMF to the intermediate SMF may not include indication information indicating that the UE is outside the LADN service area.

[0095] S305: The intermediate SMF sends a request message to the anchor SMF.

[0096] Optionally, the request message sent by the intermediate SMF to the anchor SMF is a session context request message. The challenge message is used to query the anchor SMF for the session context corresponding to the session ID.

[0097] Optionally, the session context request message sent by the intermediate SMF to the anchor SMF may include second indication information. The second indication information is used to indicate that the UE is outside the LADN service area.

[0098] Optionally, the session context request message may further include indication information for requesting session activation.

[0099] S306: The anchor SMF sends a response message to the intermediate SMF, where the response message may be a session context response message.

[0100] For example, the intermediate SMF receives a session context response message from the anchor SMF. The message includes the session context. The intermediate SMF determines, based on the session context, that the session is an LADN session. The intermediate SMF rejects the session that matches the session ID. For example, the session context sent by the anchor SMF to the intermediate SMF includes first pointing information. The first indication information is used to indicate that the DNN corresponding to the current session is a LADN.

[0101] As another example, the intermediate SMF receives a session context response message from the anchor SMF. Optionally, the session context response message includes cause information. The intermediate SMF rejects the session that matches the session ID. Optionally, after the anchor SMF receives a session context request message from the intermediate SMF, if the anchor SMF determines that the current session is a LADN session, the anchor SMF rejects passing the session context to the intermediate SMF and includes the reason information in the session context response message . The reason information may be: I-SMF insertion rejected for LADN session.

[0102] S307: The intermediate SMF rejects the session corresponding to the session ID.

[0103] That the intermediate SMF rejects the session corresponding to the session ID can have multiple implementations: the intermediate SMF rejects the engagement of the session corresponding to the session ID, or the intermediate SMF rejects the user plane engagement of the session corresponding to the session ID, or the intermediate SMF decides to disconnect the session, corresponding to the session ID. It should be understood that in a handover scenario, the intermediate SMF rejects the handover of the session corresponding to the session ID, or the intermediate SMF rejects the user plane engagement of the session corresponding to the session ID, or the intermediate SMF decides to release the session corresponding to the session ID. The user plane includes a handover path between RAN and UPF and/or a radio connection between UE and RAN.

[0104] As an example, the session context response message received by the intermediate SMF from the anchor SMF includes the session context. The session context may include first pointing information. The first indication information is used to indicate that the DNN corresponding to the current session is a LADN. The intermediate SMF rejects the session that matches the session ID.

[0105] As another example, the session context response message received by the intermediate SMF from the anchor SMF includes cause information. The intermediate SMF rejects the session that matches the session ID.

[0106] Optionally, when the intermediate SMF determines that the session corresponding to the session ID is an LADN session, in other words, the current session is an LADN session, the intermediate SMF rejects the session corresponding to the session ID.

[0107] The intermediate SMF determines that the current session is a LADN session as follows: The session context sent by the anchor SMF to the intermediate SMF includes first indication information, wherein the first indication information is used to indicate that the DNN corresponding to the current session , is LADN. Alternatively, the intermediate SMF determines based on the configuration information that the session is an LADN session, where the configuration information may be, for example, information stored in the intermediate SMF. Alternatively, the intermediate SMF may determine based on the second indication information sent by the Access and Mobility Management Function (AMF) that the session is an LADN session, the second indication information being used to indicate that the UE is outside the LADN service area. There can be a variety of ways that an intermediate SMF determines that a session is a LADN session. In this embodiment, this is not limited.

[0108] Optionally, after the intermediate SMF determines, based on the first indication information sent by the anchor SMF, that the current session is a LADN session, the intermediate SMF discards the session corresponding to the session ID, terminates the session invocation, or terminates the session user plane invocation. The session user plane is the data path.

[0109] S308: The intermediate SMF sends the first message to the AMF.

[0110] Optionally, the first message may be a session context response message.

[0111] Optionally, the first message includes information about the reason for rejecting the corresponding session.

[0112] The intermediate SMF sends cause information to the AMF to notify the AMF that the engagement of the current session, namely the LADN session, has been rejected. Alternatively, the intermediate SMF sends cause information to the AMF to notify the AMF that the user plane engagement of the current session has been rejected.

[0113] Optionally, the reason information is used to indicate the reason why the session cannot be activated. For example, the reason might be: Insertion of the intermediate SMF and intermediate UPF was rejected for the LADN session.

[0114] In addition, it should be understood that the embodiment shown in FIG. 3 may further include a second implementation. In the second implementation, the anchor SMF determines that the current session is an LADN session and rejects the session corresponding to the session ID.

[0115] The second implementation includes steps S301 to S303 and S309 to S313. For a detailed description of steps S301-S303, refer to the above descriptions. Details are not described here.

[0116] S309: The AMF sends a create session context request message to the intermediate SMF.

[0117] S310: The intermediate SMF sends a request message to the anchor SMF.

[0118] The intermediate SMF sends a session update request message or a create session request message to the anchor SMF. The session update request message or session create request message includes a session identifier. Alternatively, the intermediate SMF sends a context request message to the anchor SMF. This process is similar to step S305. For details, see the description of step S305.

[0119] Optionally, the anchor SMF receives a session update request message or a create session request message sent to the intermediate SMF and determines that the request message is used to request insertion of the intermediate SMF.

[0120] For example, the anchor SMF receives a session update request or a create session request sent by a new intermediate SMF and determines that the request message is used to insert the intermediate SMF.

[0121] S311: The anchor SMF rejects the session corresponding to the session ID.

[0122] After the anchor SMF receives the request message from the intermediate SMF, when the anchor SMF determines that the session corresponding to the session ID is a LADN session, the anchor SMF rejects the session. The session rejection may specifically be: the anchor SMF rejects the engagement of the session corresponding to the session ID, or the anchor SMF rejects the engagement of the session user plane corresponding to the session ID, or the anchor SMF subsequently releases the session corresponding to the session ID, or the anchor SMF decides to abort (de -activate) of the session corresponding to the session ID. The anchor SMF may determine based on the session context that the current session is an LADN session. For example, the session context includes first pointing information. The first indication information is used to indicate that the DNN corresponding to the current session is a LADN. Alternatively, the anchor SMF may determine the LADN session based on information configured in the anchor SMF. For example, the configured information may indicate which DNN stored by the anchor SMF is the LADN.

[0123] Optionally, if the request message in step S310 is a context request message, when the session corresponding to the session ID is an LADN session, the anchor SMF rejects passing the session context to the intermediate SMF and includes the reason information in the session context response message. The cause information may indicate that: Intermediate SMF and User Plane Function (UPF) insertion is rejected for the LADN session.

[0124] It should be noted that if the description in FIG. 3 is used as a reference to the corresponding description in FIG. 4, the description of session activation should be appropriately understood as a description of session handover.

[0125] Optionally, there can be multiple ways in which the anchor SMF defines the LADN session. In particular, the anchor SMF may determine the LADN session based on the information configured in the anchor SMF. Alternatively, the anchor SMF may determine based on the session context that the current session is an LADN session. For example, the anchor SMF may determine, based on the first indication information that is in the session context and that is used to indicate that the DNN corresponding to the current session is an LADN, that the current session is an LADN session. The configured information may be LADN information stored by the anchor SMF, such as information indicating which DNN is the LADN.

[0126] S312: The anchor SMF sends a second message to the intermediate SMF.

[0127] Optionally, the second message may be a session context creation response message.

[0128] The second message includes indication information or reason information. The indication information or reason information is used to indicate that the session cannot be activated. Alternatively, the indication information or reason information is used to indicate that the intermediate SMF does not involve the session user plane. In other words, the intermediate SMF decides, based on the indication information, to reject the invocation of the user session plane. The user plane includes a transmission path between the RAN and the UPF and/or a radio connection between the UE and the RAN. It should be noted that in the embodiment of FIG. 4, the indication information should accordingly be understood as being used to indicate that the session service cannot be transferred.

[0129] It should be understood that the indicator information may indicate the corresponding information in various scenarios. For example, in a service request scenario, namely a session engagement request scenario, the indication information is used to indicate that the session cannot be activated, or is used to indicate to the intermediate SMF not to engage the session user plane. In a handover scenario, indication information is used to indicate that the session cannot be handed over.

[0130] Optionally, the second message further includes rejection reason information for the current LADN session. For example, the reason might be: Insertion of the intermediate SMF and intermediate UPF was rejected for the LADN session.

[0131] Optionally, the second message sent by the anchor SMF to the intermediate SMF is used to indicate that the anchor SMF rejects the engagement of the session corresponding to the session ID, namely the LADN session. In other words, the anchor SMF sends a reject message to the intermediate SMF to notify the intermediate SMF that the current session cannot be brought up, or that the current session has ended.

[0132] Optionally, the second message sent by the anchor SMF to the intermediate SMF carries reason information used to indicate that session initiation was rejected or invocation failure reason information used to indicate that the session could not be revived. For example, the reason information could be: Intermediate SMF and Intermediate UPF Insertion Rejected for LADN Session.

[0133] S313: The intermediate SMF sends indication information in the second message to the AMF.

[0134] Optionally, the intermediate SMF sends the cause information in the second message to the AMF.

[0135] FIG. 4 is a flowchart of another session processing method according to one embodiment of the present application.

[0136] For ease of understanding, the scenario to which this embodiment is applied is first briefly described.

[0137] This embodiment is applicable to the process in which the UE is moving. Specifically, the UE establishes an LADN session in the LADN service area. When the UE moves outside the anchor SMF coverage area, the UE initiates a handover procedure (applicable to Xn handover and N2 handover) to request LADN session handover. In this case, AMF handover may or may not be performed. In this embodiment, it is determined that the insertion of an intermediate SMF and an intermediate UPF to continue accessing the LADN service is not allowed. For example, in one implementation, the LADN service area can be assumed to be a subset of the anchor SMF's service area. In other words, the LADN service area is included in the anchor SMF service area. When the UE moves outside the anchor SMF's coverage area, the UE necessarily moves outside the LADN's coverage area. The difference of this option from the option shown in Fig.3 is that if the handover is slow in the handover procedure, additional processing may be required, such as disconnecting or terminating the LADN session.

[0138] Steps S401 to S408 in the present application are similar to steps S301 to S308 in FIG. See the descriptions above for related descriptions. To avoid repetition, the details are not described here. It should be noted that the session activation described in the steps in FIG. 3 should be respectively understood as session handover in this embodiment.

[0139] In this embodiment, when the intermediate SMF is the executing entity, in other words, the intermediate SMF decides to reject session handover, the corresponding procedure further includes the following step:

[0140] After the intermediate SMF rejects the session corresponding to the session ID, the intermediate SMF sends a first message to the AMF, wherein the second message includes reason information for rejecting the current LADN session. That the intermediate SMF rejects the session corresponding to the session ID means that the intermediate SMF rejects the handover of the session corresponding to the session ID. The reason information is used to indicate the reason why the intermediate SMF rejects the handoff of the session corresponding to the session ID.

[0141] After the AMF receives the first message, the method further includes the following steps.

[0142] S409: AMF sends a handover command to the RAN.

[0143] Optionally, the handover command sent by the AMF to the RAN includes handover failure indication information. The handover failure indication information may be used to indicate that when the session corresponding to the session ID is an LADN session, the handover of the session is not performed or approved, or the handover procedure is terminated.

[0144] Optionally, the handover command may further include failure reason information. For example, the failure reason information could be: insertion of intermediate SMF and intermediate UPF rejected for LADN session.

[0145] S410: The AMF sends a session release request message to the anchor SMF.

[0146] Optionally, upon receiving a session release request message sent by the AMF, the anchor SMF terminates or releases the LADN session. It should be understood that prior art should be consulted for the process in which the anchor SMF disconnects or terminates the LADN session. Details are not described here.

[0147] In addition, when the target of this embodiment of the present application is the anchor SMF, in other words, the anchor SMF decides to reject the session, the method further includes steps S411-S417. Steps S411-S415 are the same as steps S309-S313 in Fig.3. See the previous descriptions for detailed descriptions. To avoid repetition, the details are not described here.

[0148] It should be understood that in the session handover procedure in this embodiment, the anchor SMF rejects the session: the anchor SMF rejects the handover of the session corresponding to the session ID. If the execution object is an anchor SMF, the method further includes the following steps:

[0149] S416: AMF sends a handover command to the RAN.

[0150] Optionally, the handover command sent by the AMF to the RAN includes failure indication information. The failure indication information may be used to indicate that the session handover failed or was not approved, or the handover procedure was terminated.

[0151] Optionally, the handover command may further include failure reason information. For example, the failure reason information could be: insertion of intermediate SMF and intermediate UPF rejected for LADN session.

[0152] S417: The AMF sends a session release request message to the anchor SMF.

[0153] Optionally, upon receiving a session release request message sent by the AMF, the anchor AMF terminates or disconnects the LADN session. It should be understood that prior art should be consulted for the process in which the anchor SMF disconnects or terminates the LADN session. Details are not described here.

[0154] FIG. 5 is a flowchart of a session processing method according to one embodiment of the present application.

[0155] The session processing method is applicable to a handover procedure initiated by UE movement. For example, the session processing method is applicable to a process in which the UE moves outside the LADN service area or the UE moves outside the anchor SMF coverage area. The method includes step S510, step S520, and step S530.

[0156] S510: The first intermediate SMF receives the first indication information. The first indication information is used to indicate that the DNN corresponding to the current session is an LADN, or is used to indicate that the current session is an LADN session.

[0157] Optionally, in a scenario in which an intermediate SMF is inserted, the first intermediate SMF is the inserted target intermediate SMF. In other words, there is no intermediate SMF for the LADN session before the UE moves. After the UE moves, especially after the UE moves outside the coverage area of the anchor SMF, it is necessary to insert an intermediate SMF. The intermediate SMF is the target intermediate SMF.

[0158] Optionally, in a scenario in which an intermediate SMF needs to be handed over, in other words, it is necessary to perform a handover from a source intermediate SMF to a target intermediate SMF, the first intermediate SMF is the target intermediate SMF used after the handover. The initial intermediate SMF may be an intermediate SMF used prior to performing the intermediate SMF handoff procedure. The target intermediate SMF may be an intermediate SMF, namely a new intermediate SMF used after the intermediate SMF handover procedure has been performed. It should be understood that the target intermediate SMF cannot be configured with LADN information.

[0159] It should be understood that the first intermediate SMF may be inserted, modified, or removed depending on the requirement.

[0160] Optionally, the first indication information received by the first intermediate SMF may be sent by different network elements. For example, the network element that sends the first indication information may be a source AMF, a target AMF, an anchor SMF, or a source intermediate SMF. In the scenario in which AMF handover is performed, the original AMF is the AMF from which the UE is handed over, namely the old AMF, and the original AMF is configured with LADN information. The target AMF is the AMF to which the UE is handed over, namely the new AMF, and the target AMF may not be configured with LADN information. The LADN information may be, for example, the LADN service area or other LADN related information. Specific implementations in which various network elements send the first indication information are detailed below.

[0161] S520: The first intermediate SMF rejects the current session.

[0162] As an example, if the first intermediate SMF receives the first indication information, and the message received by the first intermediate SMF from the target AMF does not include indication information, such as the presence of the UE in the LADN indication information used to indicate whether The UE is in the LADN service area, then the first intermediate SMF determines that the UE is outside the LADN service area.

[0163] Optionally, when the first intermediate SMF determines that the UE is outside the LADN service area, the first intermediate SMF may directly reject the session, in other words, the first intermediate SMF may disconnect or terminate the LADN session. Alternatively, the first SMF may send a message to the AMF, wherein the message contains reason information.

[0164] S530: Optionally, the first intermediate SMF sends second indication information to the anchor SMF.

[0165] It should be noted that if the first intermediate SMF terminates the LADN session, then the first intermediate SMF may not send the second indication information to the anchor SMF.

[0166] Optionally, if the first intermediate SMF determines that the UE is moving outside the LADN service area, the first intermediate SMF sends to the anchor SMF second indication information used to indicate that the UE is outside the LADN service area. LADN.

[0167] Specifically, when the target AMF is not configured with LADN information, the target AMF does not send indication information indicating whether the UE is in the LADN service area to the first intermediate SMF. Since the first intermediate SMF knows, based on the first indication information, that the current session is an LADN session, the first intermediate SMF may determine that the UE is moving outside the LADN service area. The first intermediate SMF then sends the second pointing information to the anchor SMF.

[0168] Optionally, when the second message includes indication information indicating that the UE is outside the LADN service area, the first intermediate SMF forwards the indication information to the anchor SMF. Specifically, when the target AMF is configured using the LADN information, the target AMF may determine based on the LADN service area and the location of the UE that the UE is moving outside the LADN service area, and the target AMF may send to the first intermediate SMF the second indication information used for indicating that the UE is moving outside the LADN service area.

[0169] Optionally, for example, the second indication information may be: the presence of the UE in the LADN indication is "IN" or "OUT" ("OUT"). When the indication is "OUT", it indicates that the UE is outside the LADN service area. When the indication is "B", it indicates that the UE is in the LADN service area.

[0170] It should be understood that the anchor SMF learns based on the second indication information that the UE is moving outside the LADN service area and may further disconnect or terminate the LADN session established by the UE. Specifically, the anchor SMF may send a message to the target AMF used to terminate the LADN session, or the anchor SMF may send a message to the A-UPF including information used to indicate the release of the N3 tunnel of the LADN session.

[0171] FIG. 6 is a flowchart of a session processing method according to one embodiment of the present application.

[0172] For ease of understanding, the scenario and network elements in Fig. 6 are first briefly described.

[0173] This embodiment is applicable to a scenario in which an AMF handoff is performed and the intermediate SMF is not changed. Before performing the AMF handoff, the original AMF manages the access and mobility service of the UE, and the RAN with which the UE is connected connects through the intermediate UPF managed by the first intermediate SMF to the anchor UPF managed by the anchor SMF. After the AMF handoff is performed for the UE, the source AMF detects that the source AMF can no longer serve the UE. The source AMF selects the target AMF as the new AMF to serve the UE. In other words, an AMF handoff is performed. In this case, the handover is not performed on the first intermediate SMF. In other words, the RAN with which the UE is connected is still connected via the intermediate UPF managed by the first intermediate SMF to the anchor UPF managed by the anchor SMF. The specific procedure for implementing this embodiment is shown in FIG. 6, and the steps are described below.

[0174] S601: The source RAN sends a handover request message to the target RAN.

[0175] For example, when the UE is further away from the source RAN but closer to the target RAN, the UE may receive a better signal from the target RAN. Therefore, the source RAN selects the target RAN and sends a handover request message to the target RAN.

[0176] Optionally, a handover request message is used to request from the target RAN to handover the UE to the target RAN. The handover request message may carry information about the LADN session to be handed over, such as a session ID corresponding to an LADN session or a list of session IDs corresponding to a plurality of LADN sessions. It should be understood that the handover request message may further include a session ID corresponding to a non-LADN session, but a session ID corresponding to a non-LADN session is not involved in this embodiment of the present application. Therefore, there is no special description. In this embodiment, the number of LADN sessions is not limited.

[0177] S602: The source AMF sends a create UE context request message to the target AMF.

[0178] Optionally, when it is detected that the source AMF can no longer serve the UE, the source AMF selects the target AMF as a new AMF to serve the UE. For the procedure for selecting the target AMF, please refer to the existing procedure. Details are not described here.

[0179] Optionally, a create UE context request message sent by the source AMF to the target AMF is used to request the target AMF to create a UE context. The create UE context request message may carry UE context information stored in the original AMF. The UE context information may include, for example, a DNN and an SMF that correspond to the session ID of the LADN session.

[0180] S603: The target AMF sends a session creation request message or a session update request message to the first intermediate SMF.

[0181] Optionally, in the handover procedure of the UE, handover is not performed in the first intermediate SMF. The first intermediate SMF is configured with LADN information. For example, the LADN information may be: The DNN corresponding to the current session is an LADN or the current session is an LADN session.

[0182] Optionally, the create session request message or session update request message includes a first AMF identifier.

[0183] Optionally, the first intermediate SMF sends a response message to the target AMF to a create session request message or a session update request message. When an Xn interface exists between the S-RAN and the T-RAN, the response message sent by the first intermediate SMF to the target AMF may further include a forward forward indication to direct the source RAN to directly forward data to the target RAN. Alternatively, the response message may be uplink tunnel information, such as an IP address or tunnel endpoint, for the I-UPF selected and inserted by the first intermediate SMF.

[0184] It should be noted that all of the following steps (steps S604-S612) are described for one session ID. In the case where the handover request message includes a plurality of session IDs, steps S604-S612 are performed for the session corresponding to each of the session IDs.

[0185] S604: The target AMF sends a handover request message to the target RAN.

[0186] Optionally, after receiving the uplink tunnel information related to the I-UPF and sent by the first intermediate SMF, the target AMF sends a handover request message to the target RAN. The request message is used to query the target RAN to allow the UE to access the target RAN.

[0187] Optionally, the handover request message may carry I-UPF uplink tunnel information.

[0188] Optionally, when the first session corresponds to the I-UPF set, the handover request message carries uplink tunnel information for the I-UPF set.

[0189] S605: The target RAN sends a handover request confirmation message to the target AMF.

[0190] For example, after receiving a handover request message sent by the target AMF, the target RAN creates a corresponding resource in the target RAN and sends a handover request confirmation message to the target AMF.

[0191] Optionally, the resource created by the target RAN may include an N3 tunnel downlink resource. The downlink resource of the N3 tunnel may be, for example, the IP address of the target RAN or the endpoint number of the N3 tunnel.

[0192] Optionally, the handover request confirmation message sent by the target RAN to the target AMF includes an N3 tunnel downlink resource created by the target RAN.

[0193] S606: The target AMF sends a create context response message to the source AMF.

[0194] For example, after creating resources in the target RAN and the target AMF, the target AMF sends a create context response message to the source AMF. The create context response message is used by the target AMF to notify the source AMF that resources have been created in the target RAN and the target AMF.

[0195] Optionally, the create context response message sent by the target AMF to the source AMF can be further used to request the source RAN in the LADN to perform a UE handoff operation from the source RAN to the target RAN.

[0196] S607: The UE is handed over from the source RAN to the target RAN.

[0197] For a specific procedure in which a UE is handed over from a source RAN to a target RAN, refer to the existing procedure. Details are not described here.

[0198] S608: The target RAN sends a handover notification message to the target AMF.

[0199] For example, the target RAN sends a handover notification message to the target AMF after the UE completes the handover procedure. The handover notification message is used to notify the target AMF that the UE has been successfully handed over to the target RAN.

[0200] S609: The target AMF sends a session update message to the first intermediate SMF.

[0201] Optionally, a create session request message or a session update request message is the third message.

[0202] Optionally, if the target AMF is not configured with LADN related information, the session update message sent to the first intermediate SMF does not include indicator information used to indicate that the UE is outside the LADN service area.

[0203] S610: The first intermediate SMF determines that the UE is outside the LADN service area.

[0204] It should be understood that the first intermediate SMF may determine that the current session is an LADN session or that the DNN corresponding to the current session is an LADN. Specifically, the manner in which the first intermediate SMF learns that the current session is an LADN session or the DNN corresponding to the current session is an LADN may include the following: The originating AMF notifies the first intermediate SMF with the LADN information. Alternatively, when the first intermediate SMF is inserted, the first intermediate SMF obtains a session context from the anchor SMF, wherein the session context includes indication information indicating that the DNN corresponding to the current session is an LADN or the current session is an LADN session. It should be understood that the first intermediate SMF may learn the LADN information in a variety of other ways. In this embodiment, this is not limited.

[0205] Optionally, when the second message that is sent to the target AMF and received by the first intermediate SMF does not include indication information used to indicate that the UE is outside the LADN service area, because the first intermediate SMF can determine that the current session is an LADN session, the first intermediate SMF determines that the UE is outside the LADN service area. The second message may be a session update message.

[0206] Optionally, when the first intermediate SMF determines that the UE is outside the LADN service area, the first intermediate SMF may directly reject the session, in other words, the first intermediate SMF may disconnect or terminate the LADN session. In this case, step S611 and step S612 may be skipped in this embodiment. In addition, the first intermediate SMF may send a notification message to the AMF, wherein the message carries reason information.

[0207] S611: The first intermediate SMF sends the second indication information to the anchor SMF.

[0208] Optionally, when the first intermediate SMF does not disconnect or terminate the session, the anchor SMF may perform an operation to disconnect or terminate the session.

[0209] Optionally, upon determining that the UE is moving outside the LADN, the first intermediate SMF sends second indication information to the second SMF. The second indication information is used to indicate that the UE is moving outside the LADN. The second indication information may be as follows: the presence of the UE in the LADN indication is "OUT".

[0210] S612: Anchor SMF performs a first session release or termination operation.

[0211] Optionally, when the first intermediate SMF does not disconnect or terminate the session, the anchor SMF may perform an operation to disconnect or terminate the session.

[0212] For example, the second SMF learns based on the second indication information that the UE is moving outside the LADN, and may disconnect or terminate the LADN session established by the UE. Specifically, the SMF may send a message to the AMF used to terminate the LADN session, or the SMF may send a message to the UPF including information used to indicate that the N3 tunnel of the LADN session has been terminated.

[0213] Regarding the operation to disconnect or terminate the session performed by the second SMF, refer to the prior art. Details are not described here.

[0214] FIG. 7 is a flowchart of another session processing method according to one embodiment of the present application.

[0215] For ease of understanding, a scenario to which this embodiment can be applied is briefly described.

[0216] This embodiment is applicable to a scenario in which an AMF handover is performed and the intermediate SMF used after the handover is a new intermediate SMF inserted. In particular, the handover procedure is initiated by the movement of the UE. An AMF handover is in progress. The original AMF (namely, the old AMF) is configured with the LADN information, and the UE establishes an LADN session in the LADN service area. After performing the handover, the UE is handed over from the source AMF to the target AMF (namely, the new AMF). The target AMF is not configured with LADN information. In addition, the handover procedure includes the following two specific scenarios: (1) There is no intermediate SMF for the LADN session before the handover (in other words, the original intermediate SMF is not involved). After the handover, the UE moves out of the coverage area of the anchor SMF. Therefore, the first intermediate SMF must be inserted. (2) Before the handover, there is an intermediate SMF (namely, the original intermediate SMF) for the LADN session. After the handover, it is necessary to perform a handover from the source intermediate SMF to the new intermediate SMF, namely the target intermediate SMF. The specific procedure for implementing this embodiment is shown in Fig. 7, and the steps are described below.

[0217] The process of interaction of network elements in Fig.7 is as follows.

[0218] Step S701 is similar to step S601 in Fig.6. For a specific implementation method, refer to the previous description of step S601. To avoid repetition, the details are not described here.

[0219] S702: The source AMF sends a create UE context request message to the target AMF.

[0220] Optionally, when it is detected that the source AMF can no longer serve the UE, the source AMF selects the target AMF as a new AMF to serve the UE. For the procedure for selecting the first AMF, refer to the existing procedure. Details are not described here.

[0221] Optionally, a create UE context request message is used to request the target AMF to create a UE context. The create UE context request message may further carry UE context information stored in the original AMF. The UE context information may include, for example, a DNN and an SMF that correspond to the session ID of the PDU.

[0222] Optionally, when the session is an LADN session, the first indication information used is carried in the UE Creation Context Request message. The first indication information is used to indicate that the DNN of the current session is an LADN or that the current session is an LADN session. It should be understood that when the target AMF is not configured with LADN information, the target AMF can learn based on the first indication information that the current session is an LADN session.

[0223] Optionally, after the target AMF knows, based on the first indication information, that the current session is an LADN session, if the target AMF is configured with LADN service area information, the target AMF may determine based on the UE location and service area LADN whether the UE moves outside the LADN service area.

[0224] Optionally, after the target AMF knows, based on the first indication information, that the current session is an LADN session, if the target AMF is not configured with information such as the LADN service area, the target AMF may determine that the UE is located outside the LADN service area.

[0225] Steps S703-S708 are similar to steps S603-S608 in FIG. For a particular implementation, refer to the previous description of the relevant steps. To avoid repetition, the details are not described here.

[0226] Steps S709-S712 in FIG. 7 will now be described.

[0227] S709: The target AMF sends a session update message to the first intermediate SMF, wherein the session update message includes second indication information used to indicate that the UE is outside the LADN service area.

[0228] Optionally, a create session request message or a session update request message is the third message.

[0229] For example, if the target AMF determines in step S702 that the UE is outside the LADN service area, the second message sent to the first intermediate SMF includes the second indication information. The second indication information is used to notify the first SMF that the UE is outside the LADN service area. For example, the second indication information may be: the presence of the UE in the LADN indication is "OUT".

[0230] It should be understood that when there is an intermediate SMF for the LADN session before the handover and the UE moves outside the service area of the original intermediate SMF during the move, the first intermediate SMF is the target intermediate SMF used after the handover. When there is no intermediate SMF for the LADN session before the handover and the UE moves out of the coverage area of the anchor SMF while moving, the first intermediate SMF is the inserted target intermediate SMF.

[0231] S710: The first intermediate SMF rejects the current session.

[0232] As an example, the first intermediate SMF learns, through steps S704 and step S705, that the current session is an LADN session or the DNN corresponding to the current session is an LADN. If the message that is sent to the target AMF and received by the first intermediate SMF in step S709 does not include indication information used to indicate that the UE is outside the LADN service area, the first intermediate SMF may determine that the UE is outside the service area. LADN.

[0233] As another example, after the target AMF knows in step S702 based on the first indication information that the current session is an LADN session, if the target AMF is not configured with information such as the LADN service area, the target AMF may determine that the UE is outside the LADN service area. If the message that is sent to the target AMF and received by the first intermediate SMF in step S709 includes indication information used to indicate that the UE is outside the LADN service area, the first intermediate SMF may determine that the UE is outside the LADN service area. .

[0234] Optionally, when the first intermediate SMF determines that the UE is outside the LADN service area, the first intermediate SMF may directly reject the current session, in other words, the first intermediate SMF may disconnect or terminate the LADN session. In this case, step S711 and step S712 may be omitted in this embodiment.

[0235] S711: The first intermediate SMF sends the second indication information to the anchor SMF.

[0236] Optionally, when the first intermediate SMF does not disconnect or terminate the session, the anchor SMF may perform an operation to disconnect or terminate the session.

[0237] Optionally, upon determining that the UE is moving outside the LADN, the first intermediate SMF sends second indication information to the second SMF. The second indication information is used to indicate that the UE is moving outside the LADN. The second indication information may be as follows: the presence of the UE in the LADN indication is "OUT".

[0238] S712: Anchor SMF performs a first session release or termination operation.

[0239] Optionally, when the first intermediate SMF does not disconnect or terminate the session, the anchor SMF may perform an operation to disconnect or terminate the session.

[0240] For example, the second SMF learns based on the second indication information that the UE is moving outside the LADN, and may disconnect or terminate the LADN session established by the UE. Specifically, the SMF may send a message to the AMF used to terminate the LADN session, or the SMF may send a message to the UPF including information used to indicate to terminate the N3 tunnel of the LADN session.

[0241] Regarding the operation to disconnect or terminate the session performed by the second SMF, refer to the prior art. Details are not described here.

[0242] In this embodiment, the source AMF sends the LADN session indication information to the target AMF, and the target AMF may know that the current session is an LADN session. The intermediate SMF then sends indication information to the anchor SMF indicating that the UE is moving out of the LADN service area. Thus, in a scenario where there are two SMFs, the intermediate SMF or anchor SMF may terminate or disconnect the current session to conserve LADN service resources.

[0243] FIGS. 8A and 8B show a flowchart of yet another session processing method according to one embodiment of the present application. The method includes steps S801 to step S813. For ease of understanding, a scenario to which this embodiment can be applied is briefly described.

[0244] This embodiment is applicable to a handover procedure initiated by UE movement. An AMF handover is in progress. The AMF used before the handover is the original AMF, and the original AMF is configured with LADN information. The post-handoff AMF is the target AMF, and the target AMF is not configured with LADN information. Before handover, the UE establishes an LADN session in the LADN service area. In addition, there is an intermediate SMF (namely, the original intermediate SMF) for the LADN session before the handover. After handover, the LADN session must be handed over to a new intermediate SMF (namely, the target intermediate SMF). The specific procedure for implementing this embodiment is shown in FIG. 8, and the steps are described below.

[0245] Steps S801 to S803 are the same as steps S601 to S603 in FIG. For a specific implementation method, refer to the previous description of steps S601-S603. To avoid repetition, the details are not described here.

[0246] S804: The source intermediate SMF sends the first indication information to the target intermediate SMF.

[0247] Optionally, the source intermediate SMF may send a session context to the target SMF. The session context includes first indication information, and the first indication information is used to indicate that the DNN corresponding to the current session is an LADN or that the current session is an LADN session. In other words, the target intermediate SMF can learn from the source intermediate SMF that the current session is an LADN session.

[0248] Optionally, the way the source intermediate SMF learns that the current session is a LADN session, or the source intermediate SMF obtains the first indication information, may include the following: When the source intermediate SMF is inserted, the source intermediate SMF obtains the session context from the anchor SMF , wherein the session context includes pointing information used to indicate that the DNN corresponding to the current session is an LADN or that the current session is an LADN session. Alternatively, in an intermediate SMF handoff scenario, the original intermediate SMF obtains a session context from the intermediate SMF used before the handover, wherein the session context includes indication information used to indicate that the DNN corresponding to the current session is LADN or the current session is a LADN session. Alternatively, when the original intermediate SMF is inserted, the original AMF notifies the original intermediate SMF with indication information used to indicate that the DNN corresponding to the current session is an LADN or that the current session is an LADN session. Alternatively, the original intermediate SMF may be preconfigured with LADN session related information. It should be understood that, in addition, there may be many other ways in which the source intermediate SMF learns that the current session is a LADN session, or the source intermediate SMF obtains the first indication information. This application is not limited.

[0249] Steps S805-S809 are similar to steps S604-S608 in Fig.6. For a specific implementation process, refer to the previous descriptions of steps S604-S608. To avoid repetition, the details are not described here.

[0250] S810: The target AMF sends a session update message to the first intermediate SMF.

[0251] Optionally, a create session request message or a session update request message is the third message.

[0252] Optionally, the target AMF is not configured with associated LADN information. Therefore, the session update message sent to the target intermediate SMF does not include indication information indicating whether the UE is moving outside the LADN.

[0253] Optionally, the target intermediate SMF learns based on the first indication information in step S804 that the current session is an LADN session. Therefore, when the target intermediate SMF does not receive indication information that is sent by the target AMF that indicates whether the UE has moved outside the LADN, the target intermediate SMF may determine that the UE has moved outside the LADN service area.

[0254] S811: The first intermediate SMF rejects the current session.

[0255] As an example, the first intermediate SMF learns in step S804 that the current session is an LADN session or the DNN corresponding to the current session is an LADN. If the second message that is sent to the target AMF and received by the first intermediate SMF in step S810 does not include indication information used to indicate that the UE is not in the LADN service area, the first intermediate SMF determines that the UE is not in the service area LADN.

[0256] Optionally, when the first intermediate SMF determines that the UE is not in the LADN service area, the first intermediate SMF may directly reject the session, in other words, the first intermediate SMF may disconnect or terminate the LADN session. In this case, step S812 and step S813 may be skipped in this embodiment. In addition, the first SMF may send a message to the AMF, wherein the message contains reason information. For a specific method, refer to the descriptions in Embodiment 3 and Embodiment 4.

[0257] S812: The first intermediate SMF sends the second indication information to the anchor SMF.

[0258] Optionally, when the first intermediate SMF does not disconnect or terminate the session, the anchor SMF may perform an operation to disconnect or terminate the session.

[0259] Optionally, upon determining that the UE is moving outside the LADN, the first intermediate SMF sends second indication information to the second SMF. The second indication information is used to indicate that the UE is moving outside the LADN. The second indication information may be as follows: the presence of the UE in the LADN indication is "OUT".

[0260] S813: Anchor SMF performs a first session release or termination operation.

[0261] Optionally, when the first intermediate SMF does not disconnect or terminate the session, the anchor SMF may perform an operation to disconnect or terminate the session.

[0262] For example, the second SMF learns based on the second indication information that the UE is moving outside the LADN and may disconnect or terminate the LADN session established by the user equipment (UE). Specifically, the SMF may send a message to the AMF used to terminate the LADN session, or the SMF may send a message to the UPF including information used to indicate to terminate the N3 tunnel of the LADN session.

[0263] Regarding the operation to disconnect or terminate the session performed by the second SMF, refer to the prior art. Details are not described here.

[0264] FIG. 9 is a flowchart of yet another session processing method according to one embodiment of the present application.

[0265] For ease of understanding, the scenario to which this embodiment is applied is first briefly described.

[0266] This embodiment is applicable to a process in which the UE moves in the idle mode. In particular, after the UE moves outside the service area of the original AMF, a re-registration procedure is initiated. The UE is handed over from the source AMF to the target AMF. The source AMF is configured with LADN information, but the target AMF is not configured with LADN information. When the UE is served by the originating AMF, the UE establishes a session in the LADN service area. The session activity is terminated when the UE enters the idle mode. The UE includes the session identifier in the registration request to initiate a re-registration to request session activation. After moving the UE, you need to change or insert an intermediate SMF.

[0267] The session processing method shown in FIG. 9 includes steps S901-S909.

[0268] S901: The UE sends a registration request message to the target RAN.

[0269] For example, after moving to the target RAN, the idle mode UE initiates a registration request to the target RAN to which the UE is requesting access.

[0270] Optionally, the registration request message sent by the UE contains the session identifier to be used and the corresponding context. The DNN corresponding to the session ID may be LADN or some other type of network. This embodiment is only described for the case where the DNN corresponding to the session ID is LADN.

[0271] S902: The target RAN selects the target AMF.

[0272] Optionally, after receiving the registration request message sent by the UE, the target RAN selects the target AMF to serve the UE. For the procedure in which the T-RAN selects the target AMF, please refer to the existing procedure. Details are not described here.

[0273] S903: The target RAN sends a registration request message to the target AMF.

[0274] Optionally, the target RAN forwards the registration request message received in step S901 to the target AMF.

[0275] Optionally, the registration request message may include information such as the identifier of the session to be used. The DNN corresponding to the session ID is the LADN.

[0276] S904: The target AMF sends a context request message to the source AMF.

[0277] Optionally, when the registration request message received by the target AMF includes information such as a session ID to be enabled, the target AMF requests UE session context information from the source AMF.

[0278] S905: The source AMF sends a response message to the context request message to the target AMF.

[0279] Optionally, the response message includes first indication information indicating that, for example, the DNN corresponding to the session ID of the LADN session is an LADN or the session is an LADN session.

[0280] S906: The target AMF selects the first intermediate SMF.

[0281] Optionally, the target AMF may learn the LADN information based on the received first indication information.

[0282] Optionally, when the target AMF is not configured with LADN information, the target AMF determines that the UE is moving outside the LADN service area.

[0283] Optionally, in the scenario in which the intermediate SMF handoff is to be performed, in other words, the source intermediate SMF is the intermediate SMF used before the handover, and the target intermediate SMF is the intermediate SMF used after the handover, the first intermediate SMF is the target intermediate SMF used after handover.

[0284] Optionally, when there is no intermediate SMF for the session before the UE handover procedure, the first intermediate SMF is the inserted target intermediate SMF.

[0285] It should be understood that for the procedure in which the target AMF selects the first intermediate SMF, refer to the existing procedure. Details are not described here.

[0286] S907: The target AMF sends a session creation request message or a session update request message to the first intermediate SMF.

[0287] It should be understood that after the first AMF selects and inserts the first intermediate SMF or hands over to the first intermediate SMF, the first AMF sends a corresponding create session request message or a session update request message to the first intermediate SMF.

[0288] Optionally, the target AMF may determine based on the first indication information received in step S905 that the session is an LADN session. When the target AMF is not configured with LADN information, the target AMF may determine that the UE is moving outside the LADN service area. In this case, the target AMF may include the second indication information in the create session request message or the session update request message. The second indication information is used to indicate that the UE is outside the LADN service area. For example, the second indication information may be: the presence of the UE in the LADN indication is "OUT".

[0289] Optionally, the second indication information may be included in a session creation request message or a session update request message sent by the target AMF to the first intermediate SMF. Specifically, in a scenario in which an intermediate SMF handover is performed, the target AMF sends a session update request message to the first intermediate SMF. In the scenario where the intermediate SMF is reinserted, the target AMF sends a session handoff request message to the first intermediate SMF.

[0290] Optionally, the create session request message or session update request message sent by the target AMF to the first intermediate SMF may carry, for example, information that the presence of the UE in the LADN indication is "OUT".

[0291] Optionally, the target AMF may further send the first indication information to the first intermediate SMF to notify the first intermediate SMF that the DNN corresponding to the current session ID is an LADN or the current session is an LADN session.

[0292] S908: The first intermediate SMF sends the second indication information to the anchor SMF.

[0293] Optionally, after receiving the second indication information sent by the target AMF, the first intermediate SMF forwards the second indication information to the anchor SMF. The second indication information is used to indicate that the UE is moving outside the LADN service area.

[0294] Optionally, the first intermediate SMF forwards the session creation request message or the session update request message received in step S907 to the anchor SMF. The create session request message or the session update request message carries the second indication information. For example, a create session request message or a session update request message carries indication information indicating that a UE present in the LADN is "OUT".

[0295] S909: Anchor SMF terminates or disconnects the session.

[0296] Optionally, after the anchor SMF determines based on the second indication information that the UE is moving out of the LADN service area, the anchor SMF initiates a session termination or disconnect operation. For the process in which the anchor SMF terminates or disconnects the session, refer to the existing procedure. Details are not described here.

[0297] FIG. 10 is a flowchart of yet another session processing method according to one embodiment of the present application.

[0298] For ease of understanding, the scenario to which this embodiment is applied is first briefly described.

[0299] This embodiment is applicable to a scenario in which the idle mode UE initiates a service request after the idle mode UE moves. In particular, during the move, the idle mode UE moves outside the service area of the original AMF and initiates a service request procedure. The AMF is changed from the source AMF to the target AMF. When the UE is served by the originating AMF, the UE establishes a session in the LADN service area. However, the session is terminated when the UE enters the idle mode. In addition, the source AMF is configured with LADN information, but the target AMF is not configured with LADN information. In this embodiment, after moving the UE, it is necessary to change or insert an intermediate SMF.

[0300] The session processing method shown in FIG. 10 includes steps S1001-S1009.

[0301] It should be understood that an AMF handover is performed, in other words, a handover is performed from a source AMF that initially serves the UE to a target AMF. The target AMF may not be configured with LADN information.

[0302] It should also be understood that after the UE moves outside the coverage area of the anchor SMF, the target AMF may select and insert the first intermediate SMF. The first intermediate SMF selects an intermediate UPF to connect to the anchor UPF. Alternatively, after the UE moves outside the service area of the source intermediate SMF, the target AMF may reselect the intermediate SMF. The first intermediate SMF selects the intermediate UPF to connect to the anchor UPF.

[0303] S1001: The UE sends a service request message to the target RAN.

[0304] For example, after moving to the target RAN, the UE in idle mode initiates a registration request to the target RAN to which the UE is requesting access.

[0305] Optionally, the service request message sent by the UE contains a session identifier to be used. The DNN corresponding to the session ID may be LADN or some other type of network. This embodiment is only described for the case where the DNN corresponding to the session ID is LADN.

[0306] S1002: The target AMF receives a service request message sent by the target RAN.

[0307] Optionally, the service request message may include location information of the UE and indication information indicating whether the UE is outside the LADN service area. If the target AMF is not configured with LADN information, no indication information is included in the service request message. It should be noted that this step may further include interaction between the target RAN and the source RAN and/or interaction between the target AMF and the source AMF. The interaction between the target RAN and the source RAN, and the interaction between the target AMF and the source AMF are state of the art, and details are not described here.

[0308] S1003: The target AMF selects the first intermediate SMF.

[0309] Optionally, when the target AMF detects that the UE is moving outside the coverage area of the anchor SMF, the target AMF selects and inserts the first intermediate SMF. Alternatively, when the target AMF detects that the UE is moving outside the service area of the source intermediate SMF, the target AMF selects the first intermediate SMF to perform the handover of the intermediate SMF, namely the handover from the source intermediate SMF to the first intermediate SMF.

[0310] S1004: The target AMF sends a session creation request message to the first intermediate SMF.

[0311] Optionally, a create session request message is used to request the creation of a session context in the first intermediate SMF.

[0312] Optionally, the session creation request message includes information indicating whether the UE is in the LADN service area.

[0313] S1005: The first intermediate SMF requests a session context.

[0314] As an example, in step S1005a, when the target AMF detects that the UE is moving outside the coverage area of the anchor SMF, the target AMF requests a session context from the anchor SMF. The session context includes information indicating that the DNN corresponding to the current session is an LADN or the current session is an LADN session.

[0315] As another example, in step S1005b, when the target AMF detects that the UE is moving outside the coverage area of the source intermediate SMF, the target AMF requests a session context from the source intermediate SMF. The session context includes information indicating that the DNN corresponding to the current session is an LADN or the current session is an LADN session.

[0316] S1006: The first intermediate SMF determines that the UE is outside the LADN service area.

[0317] For example, the first intermediate SMF learns in step S1005 that the current session is an LADN session or the DNN corresponding to the current session is an LADN. If the message that is sent to the target AMF and received by the first intermediate SMF in step S1004 does not include indication information used to indicate that the UE is outside the LADN service area, the first intermediate SMF determines that the UE is outside the LADN service area .

[0318] Optionally, when the first intermediate SMF determines that the UE is not in the LADN service area, the first intermediate SMF may directly reject the session, in other words, the first intermediate SMF may disconnect or terminate the LADN session. In this case, step S1007 and step S1008 are not included in this embodiment. In addition, the first SMF may optionally send a message to the AMF, wherein the message contains reason information. For a specific method, refer to the descriptions in Option 3 and Option 4.

[0319] S1007: The first intermediate SMF forwards the second indication information to the anchor SMF.

[0320] Optionally, when the first intermediate SMF does not disconnect or terminate the session, the anchor SMF may perform an operation to disconnect or terminate the session.

[0321] Optionally, upon determining that the UE is moving outside the LADN, the first intermediate SMF sends second indication information to the second SMF. The second indication information is used to indicate that the UE is moving outside the LADN. The second indication information may be as follows: the presence of the UE in the LADN indication is "OUT".

[0322] S1008: Anchor SMF performs a first session release or termination operation.

[0323] Optionally, when the first intermediate SMF does not disconnect or terminate the session, the anchor SMF may perform an operation to disconnect or terminate the session. Regarding the operation to disconnect or terminate the session performed by the second SMF, refer to the prior art. Details are not described here.

[0324] FIG. 11 is a schematic structural diagram of a communication device according to one embodiment of the present application. The communication device 1100 shown in FIG. 11 may correspond to the intermediate session management function (SMF) described in the embodiment in FIG. The communication device 1100 may include a first receiving module 1101 and a first processing module 1102.

[0325] Optionally, the first receiving module 1101 may be configured to receive a request message sent by an access and mobility management function (AMF). The request message includes a session ID.

[0326] Optionally, the first processing module 1102 may be configured to: when the session corresponding to the session ID is an LADN session, to reject, by the first processing module, the session corresponding to the session ID.

[0327] Optionally, communication device 1100 may further include a second processing module. The second processing module is configured to: determine, based on the session context received from the anchor SMF, that the session is an LADN session. The session context includes first indication information used to indicate that the session is an LADN session.

[0328] Optionally, communication device 1100 may further include a third processing module. The third processing module is configured to: determine, based on the second indication information sent by the access and mobility management function (AMF), that the session is an LADN session. The second indication information is used to indicate that the UE is moving outside the LADN service area.

[0329] Optionally, communication device 1100 may further include a first send module. The first sending module is configured to send the first message to the AMF. The first message contains the reason information.

[0330] Optionally, the reason information includes the following: insertion of an intermediate SMF and an intermediate user plane function (UPF) is rejected for the LADN session.

[0331] FIG. 12 is a schematic structural diagram of a communication device according to another embodiment of the present application. The communication device 1200 shown in FIG. 12 may correspond to the AMF described in the embodiment in FIG. The communication device 1200 may include a first sending module 1201 and a first receiving module 1202.

[0332] Optionally, the first send module 1201 is configured to send a request message to the intermediate SMF. The request message includes a session identifier and the intermediate SMF is the SMF selected by the access and mobility management function (AMF) when the UE moves outside the anchor SMF's coverage area.

[0333] Optionally, the first receiving module 1202 is configured to receive the first message sent to the intermediate SMF. The first message contains the reason information.

[0334] Optionally, communication device 1200 may further include a second send module. The second sending module is configured to send cause information to a radio access network (RAN).

[0335] Optionally, communication device 1200 may further include a third send module. The third sending module is configured to send a session release request message to the anchor SMF. The session release request message is used to request the anchor SMF to release the LADN session.

[0336] FIG. 13 is a schematic structural diagram of a communication device according to another embodiment of the present application. The communication device 1300 shown in FIG. 13 may correspond to the anchor SMF described in the method shown in FIG. 3 or FIG. 4. The communication device 1300 may include a first receiving module 1301 and a first processing module 1302.

[0337] Optionally, the first receiving module 1301 is configured to receive a request message sent to the intermediate SMF. The request message includes a session identifier and the intermediate SMF is the SMF selected by the access and mobility management function (AMF) when the UE moves outside the anchor SMF's coverage area.

[0338] Optionally, the first processing module 1302 is configured to: when the session corresponding to the session ID is an LADN session, to reject by the first processing module 1302 the session corresponding to the session ID. An LADN session is a session served by an anchor SMF.

[0339] Optionally, communication device 1300 may further include a second processing module. The second processing module is configured to: determine, based on the session context, that the current session is an LADN session.

[0340] Optionally, communication device 1300 may further include a second processing module. The second processing module is configured to: determine, based on the configuration information, that the current session is an LADN session. The configuration information includes: The DNN corresponding to the current session is LADN.

[0341] Optionally, communication device 1300 may further include a second send module. The second sending module is configured to send a second message to the intermediate SMF. The second message includes reason information, and the reason information is used to indicate that the session cannot be engaged.

[0342] Optionally, what the first processing module rejects the session corresponding to the session ID includes: disconnecting the session corresponding to the session ID, or terminating the session corresponding to the session ID, or rejecting the activation or handover of the session corresponding to the session ID session.

[0343] FIG. 14 is a schematic structural diagram of a communication device according to another embodiment of the present application. The communication device 1400 shown in FIG. 14 may correspond to the first intermediate SMF described above. The communication device 1400 may include a first receiving module 1401 and a first sending module 1402.

[0344] Optionally, the first receiving module 1401 is configured to receive the first indication information. The first indication information is used to indicate that the Data Network Name (DNN) corresponding to the current session is LADN.

[0345] Optionally, the first send module 1402 is configured to send second pointing information to the anchor SMF. The second indication information is used to indicate that the UE is outside the LADN service area and the anchor SMF is the anchor SMF serving the current session.

[0346] Optionally, communication device 1400 may further include a second receiving module. The second receiving module is configured to receive a third message sent to the target AMF.

[0347] Optionally, communication device 1400 may further include a first processing module. The first processing module is configured to: when the third message does not include indication information indicating that the UE is outside the LADN coverage area, determine that the UE is outside the LADN coverage area. The target AMF is the AMF to which the UE is handed over.

[0348] Optionally, communication device 1400 may further include a second send module. The second sending module is configured: when the second message includes indication information indicating that the UE is outside the LADN service area, send the second indication information to the anchor SMF.

[0349] Optionally, the first indication information is sent by any of the following network elements: source AMF, target AMF, anchor SMF, or second intermediate SMF. The second intermediate SMF is configured to control the intermediate UPF that communicates with the source base station.

[0350] FIG. 15 is a schematic structural diagram of a communication device according to another embodiment of the present application. The communication device 1500 shown in FIG. 14 may correspond to the first target AMF described above. The communication device 1500 may include a first receiving module 1501 and a first sending module 1502.

[0351] Optionally, the first receiving module 1501 is configured to receive the first indication information sent by the AMF source. The first indication information is used to indicate that the DNN corresponding to the current session is a LADN.

[0352] Optionally, the first sending module 1502 is configured to: when the target AMF determines that the UE is moving outside the LADN service area, send the second indication information to the first intermediate SMF. The second indication information is used to indicate that the UE is outside the LADN service area, and the first intermediate SMF is configured to control the intermediate UPF that communicates with the target base station.

[0353] Optionally, communication device 1500 may further include a first processing module. The first processing module is configured to determine that the UE is moving outside the LADN service area.

[0354] Optionally, that the first processing module is configured to determine that the UE is moving outside the LADN service area includes: the first processing module is configured to determine that the UE is moving outside the LADN service area when the target AMF is not configured with LADN information.

[0355] Optionally, that the first processing module determines that the UE is moving outside the LADN service area includes: when the target AMF is configured with the LADN information, determining based on the LADN information and the location of the UE that the UE is moving outside the LADN service area.

[0356] Optionally, the LADN information includes information about the LADN service area.

[0357] FIG. 16 is a schematic structural diagram of a communication device according to a further embodiment of the present application. The communication device 1600 shown in FIG. 16 may correspond to an intermediate SMF, an anchor SMF, or an AMF in the session processing method described above. The communication device 1600 includes at least one processor 1601 and a communication interface 1602. Communication interface 1602 may be used to exchange information between communication device 1600 and another communication device. When the program instructions are executed by the at least one processor 1601, the communication device 1600 is enabled to implement the aforementioned step, method, operation, or function performed by the intermediate SMF, anchor SMF, or AMF.

[0358] It should be understood that the term "and/or" in this document only describes association relationships between associated objects and indicates that three relationships may exist. For example, A and/or B can indicate the following three cases: Only A exists, both A and B exist, and only B exists. In addition, the "/" symbol in this description usually indicates an "or" relationship between associated objects .

[0359] It should be understood that the sequence numbers of the above processes do not indicate the sequence of execution in the embodiments of the present application. The execution sequences of the processes should be determined based on the functions and internal logic of the processes and should not be considered as any limitation on the processes for implementing the embodiments of the present application.

[0360] One skilled in the art may be aware that, in combination with the examples described in the embodiments disclosed in this specification, the blocks and steps of an algorithm may be implemented by electronic hardware or a combination of computer software and electronic hardware. The performance of functions by hardware or software depends on the specific applications and the state of the design constraints of the technical solutions. A person skilled in the art can use various methods to implement the described functions for specific applications, but it should not be understood that the implementation is outside the scope of this application.

[0361] A person skilled in the art can be clear that for convenience and concise description, the detailed workflow of the above system, device and unit refers to the corresponding process in the above method embodiments, and the details are not described here.

[0362] In several embodiments presented in this application, it should be understood that the disclosed system, device and method can be implemented in another way. For example, the device embodiments described are merely examples. For example, block division is simply a division of logical functions and may be another division in a real implementation. For example, many blocks or components may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the interconnections displayed or discussed or direct links or communication connections may be implemented through some interfaces. Indirect connections or communication connections between devices or units can be implemented electrically, mechanically, or take other forms.

[0363] Blocks described as separate parts may or may not be physically separate, and parts shown as blocks may or may not be physical blocks, may be located in the same location, or may be distributed over multiple network blocks. Some or all of the blocks may be selected based on actual requirements in order to achieve the objectives of the decisions in the mentioned embodiments.

[0364] In addition, the functional blocks in the embodiments of the present application may be integrated into one processing unit, or each of the units may exist separately physically, or two or more units are integrated into one unit.

[0365] When functions are implemented in the form of a software functional block and sold or used as an independent product, the functions may be stored on a computer-readable storage medium. Based on this understanding, the essence of the technical solutions in the present application, or a certain part that contributes to the prior art, or some of the technical solutions can be implemented in the form of a software product. The computer program product is stored on a storage medium and includes several instructions for instructing a computing device (which may be a personal computer, a server, a network device, or the like) to perform all or some of the steps of the described methods. in embodiments of the present application. The above storage medium includes any medium that can store program code, such as a USB flash drive, a removable hard disk, read-only memory (ROM (Read-Only Memory)), random access memory (RAM (Random Access Memory) )) magnetic disk or optical disk.

[0366] The above description is only a specific implementation of the present application, but it is not intended to limit the scope of protection of the present application. Any variation or substitution readily found by one of ordinary skill in the art within the technical scope disclosed in this application should fall within the protection scope of this application. Therefore, the scope of protection of the present application should be determined by the scope of protection of the claims.

Claims (22)

1. A method for processing a session, comprising the steps of: receive (S310) through the anchor session management function a request message from the intermediate session control function, the method is characterized in that the request message contains a session identifier, and the intermediate session control function is a session control function connected to the access and mobility control function , and is intended to serve the UE when the UE moves outside the coverage area of the anchor session control function; And in response to determining, by the session control anchor function that the session corresponding to the session ID is a data local area network session, the session corresponding to the session ID is disconnected (S311) by the session control anchor function, wherein the data local area network service area corresponding to session of the data local area network, is in the coverage area of the binding session control function. 2. The method of claim 1, the method further comprising determining, by means of a session management anchor function based on the session context, that the session is a data local area network session. 3. The method according to claim 1 or 2, wherein the method further comprises determining by means of a session control binding function based on the configuration information that the session is a data local area network session, the configuration information comprising that the name of the data network The , corresponding to the session, is for the data local area network. 4. A method according to any one of claims 1 to 3, wherein the request message requests a session context of said session corresponding to a session identifier. 5. The method according to any one of claims 1-4, wherein the request message is used to request the insertion of an intermediate session control function. 6. A communication device comprising a first receiving module and a first processing module, wherein the first receiving module is configured to receive a request message from the intermediate session control function, wherein the device is characterized in that the request message contains a session identifier, and the intermediate session control function is a session control function connected to the access and mobility control function, and designed to serve the UE when the UE moves outside the service area of the communication device; And the first processing module is configured to: in response to determining that the session corresponding to the session ID is a data local area network session, to disconnect the session corresponding to the session identifier, while the area of the data local area network corresponding to the data local area network session, located in the service area of the communication device. 7. The communication device of claim 6, wherein the communication device further comprises a second processing module, the second processing module being configured to determine, based on the session context, that the session is a data local area network session. 8. The communication device according to claim 6, wherein the communication device further comprises a second processing module, wherein the second processing module is configured to determine based on the configuration information that the session is a data local area network session, wherein the configuration information contains that the name the data network corresponding to the session is for the data local area network. 9. Communication device according to claim 7 or 8, wherein the request message requests a session context of said session corresponding to the session identifier. 10. Communication device according to any one of claims 6-9, wherein the request message is used to request insertion of an intermediate session control function. 11. A computer-readable storage medium, wherein the computer-readable storage medium stores program instructions, and when the program instructions are executed directly or indirectly, the function of a session management anchor function is implemented in the method of any one of claims 1-5. 12. A communication device comprising at least one processor and a communication interface, wherein the communication interface is used to exchange information between a network device and another network device, and when the program instructions are executed by at least one processor, the network device implements the binding SMF function in the method according to any one of claims 1-5. 13. A communication system comprising a session management anchor function, an intermediate session management function, and an access and mobility management function, wherein the session management anchor function is configured to perform the method of any one of claims 1 to 5, the intermediate session control function is configured to send a request message to the anchor session control function, and the access and mobility control function is configured to select an intermediate session control function when the UE moves outside the coverage area of the anchor session control function. 14. A method for managing a session, comprising the steps of: selecting, by means of the access and mobility control function, an intermediate session control function to serve the UE when the UE moves outside the coverage area of the anchor session control function; sending, via the intermediate session management function, to the session management anchor function a request message containing a session identifier; receiving, by means of the anchor session management function, said request message from the intermediate session management function; And in response to determining by the session control anchor that the session corresponding to the session ID is a data local area network session, the session corresponding to the session ID is rejected by the session control anchor, the data local area network service area corresponding to the local area computer session data network, is in the coverage area of the binding session control function.

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