A session management method, network device and communication system

Abstract

The present application discloses a session management method, a network device and a communication system. According to the embodiment of the present invention, an intermediate session management entity is selected according to the location information of the UE and the PDU session demand information, so that the intermediate session management entity close to the UE can provide services for the PDU session and reduce the delay of data transmission. At the same time, the intermediate session management entity selects a user plane entity according to the location information of the UE and the PDU demand information. The intermediate session management entity is responsible for managing the user plane entities within the specified range, and does not need to manage the user plane entities of the entire PDU session, thereby reducing the complexity of management.

Description

Technical Field

[0001] The present invention relates to the field of communications, and in particular to a session management method, network equipment and a communication system. Background Art

[0002] In the network architecture of the 5G new air interface, the Session Management Function (SMF) is responsible for session management, including the establishment, modification and release of PDU (Protocol Data Unit) sessions, and the User Plane Function (UPF) is responsible for forwarding user data. In the current network architecture, there may be multiple user plane entities in the user plane path of a PDU session, and the locations of two different user plane entities among the multiple user plane entities may be far apart. For example, one user plane entity may be located near the UE's access point, while another user plane entity may be located near the data network. How to manage multiple user plane entities at different locations in a PDU session is currently under discussion. Summary of the invention

[0003] The technical problem to be solved by the embodiments of the present invention is to provide a session management method, a network device and a communication system to achieve management of user plane entities at different locations.

[0004] In a first aspect, the present application provides a session management method, including a network device selecting a first intermediate session management entity according to the location information of UE (User Equipment, user equipment, referred to as UE) and PDU (Protocol Data Unit, protocol data unit, referred to as PDU) session requirement information, and the network device sending the UE location information and PDU session requirement information to the first intermediate session management entity, wherein the PDU session requirement information is used to select a user plane entity, and the first intermediate session management entity is only responsible for managing network elements within a specified range (for example: access network equipment or user plane entity). The PDU session requirement information indicates relevant parameters of the PDU session determined by the core network. The network device is a device in the core network, and the network device can be an access management entity or a session management entity, the access management entity is used to perform access management on the UE, and the session management entity is used to manage the session established by the UE.

[0005] In the implementation of the above embodiment, the network device selects an intermediate session management entity according to the location information of the UE and the PDU session requirement information, so that the intermediate session management entity close to the UE can provide services for the PDU session and reduce the delay of data transmission. At the same time, the intermediate session management entity selects a user plane entity according to the location information of the UE and the PDU requirement information. The intermediate session management entity only manages the user plane entity within the specified range, and does not need to manage the user plane entity of the entire PDU session, thereby reducing the complexity of management.

[0006] In a possible implementation manner of the first aspect, the PDU session requirement information includes a PDU session type and / or an SSC (Session and Service Continuity, SSC for short) mode.

[0007] In a possible implementation of the first aspect, the network device selects the first intermediate session management entity for the PDU session according to the location information and PDU session requirements of the UE, including: the network device selects an intermediate session management entity that satisfies both the PDU session requirement information and whose jurisdiction includes the service base station indicated by the location information of the UE as the first intermediate session management entity. The PDU session requirement includes the PDU session type and / or SSC. The location information of the UE may be an identifier of the service base station of the UE, an identifier of the service cell of the UE, or an identifier of the tracking area of ​​the UE. The network device may determine whether the service base station indicated by the location information of the UE can be connected to the first intermediate session management entity according to the location information of the UE. Each intermediate session management entity has a certain jurisdiction, and the size of the jurisdiction is not limited in this application. For example, the jurisdiction of the intermediate session management entity is a province, a city, or a data center.

[0008] In a possible implementation of the first aspect, the PDU session requirement information includes the PDU session type and / or SSC. If the network device determines that there is no intermediate session management entity that meets both the PDU session requirement and the service base station whose jurisdiction includes the location information indication of the UE, the network device selects the second intermediate session management entity that meets the PDU session requirement information, and selects the third intermediate session management entity whose jurisdiction includes the service base station indicated by the location information of the UE, and the second intermediate session management entity and the third intermediate session management entity provide services for the PDU session at the same time. In this way, the same PDU session can be served by multiple intermediate session management entities, and each intermediate session management entity is only responsible for managing network elements within a specified range, thereby reducing the management load and complexity of the intermediate session management entity.

[0009] In a possible implementation of the first aspect, the PDU session requirement information includes a local DNN and a data transmission mode, where the local DNN indicates the name of a local DN (Data Network, DN for short). The data transmission mode indicates a transmission mode of a data packet on a user plane, and the data transmission mode is a Mutilhoming mode or a ULCL (Uplink Classifier, uplink classifier) ​​mode.

[0010] In a possible implementation of the first aspect, the network device selects a first intermediate session management entity for a PDU session based on the UE's location information and the PDU session requirement information, including: the network device selects an intermediate session management entity that satisfies both a service base station indicated by the UE's location information and a local DN indicated by a local DNN, and supports a data transmission mode included in the PDU session requirement information as the first intermediate session management entity.

[0011] In a possible implementation of the first aspect, the network device determines that there is no intermediate session management entity that has a jurisdiction including a serving base station indicated by the location information of the UE and a local DN indicated by the local DNN included in the PDU session requirement information, and supports the data transmission mode included in the PDU session requirement information, selects a second intermediate session management entity whose jurisdiction includes the serving base station indicated by the location information of the UE, and selects a third intermediate session management entity whose jurisdiction includes the local DN indicated by the local DNN included in the PDU session requirement information and supports the data transmission mode included in the PDU session requirement information. The network device may be an access management entity or a session management entity, and the second intermediate session management entity and the third intermediate session management entity provide services for the PDU session at the same time.

[0012] In a possible implementation of the first aspect, the data transmission mode is a Mutilhoming mode, and the network device sends an uplink diversion strategy and an uplink routing strategy to the first intermediate session management entity; wherein the uplink diversion strategy is used to control the branch point BP anchored by the UE to divert according to the source address of the data packet sent by the UE, and the uplink routing strategy is used to control the UE to use the IP address anchored at the anchor user plane entity or the local IP address anchored at the local anchor user plane entity as the source address of the data packet; or the network device uses the IP address anchored at the anchor user plane entity and the local IP address anchored at the anchor user plane entity as the source address of the data packet. The uplink routing policy corresponding to the IP address of the anchor user plane entity is sent to the first intermediate session management entity; the IP address anchored at the anchor user plane entity is used to enable the first intermediate session management entity to generate an uplink diversion policy, and the uplink routing policy corresponding to the IP address anchored at the anchor user plane entity is used to enable the first intermediate session management entity to generate an uplink routing policy; the uplink diversion policy is used to control the BP to divert according to the source address of the data packet sent by the UE, and the uplink routing policy is used to instruct the UE to use the IP address anchored at the anchor user plane entity or the local IP address anchored at the local anchor user plane entity as the source address to send data.

[0013] In a possible implementation manner of the first aspect, the data transmission mode is a ULCL mode, and the network device sends an uplink forwarding policy to the first intermediate session management entity, where the uplink forwarding policy is used to control the UE-anchored ULCL to forward according to a quintuple and / or an application identifier of a data packet sent by the UE.

[0014] In a possible implementation of the first aspect, in the switching process of the UE, the UE switches from the current serving base station to the target base station. Before the switching occurs, the UE has established a PDU session, and the network device saves the PDU session requirement information of the PDU session. The network device can learn from the path switching message from the target base station that the UE switches from the current serving base station to the target base station. The network device determines that the target base station is not located within the jurisdiction of the current first intermediate session management entity, and the network device selects the target intermediate session management entity, which is an intermediate session management entity that satisfies both the jurisdiction including the target base station that the UE switches to and the PDU session requirement information. Wherein, when there is no intermediate session management that satisfies both the jurisdiction including the target base station and the PDU session requirement information, the network device selects the second intermediate session management entity that has a jurisdiction including the target base station and the third intermediate session management entity that meets the PDU session requirement information, and uses the second intermediate session management entity and the third intermediate session management entity as the target intermediate session management entity.

[0015] In a possible implementation of the first aspect, the network device is a session management entity, and before the session management entity selects a first intermediate session management entity for a PDU session according to the location information and PDU session requirement information of the UE, it also includes: the session management entity determines the PDU session requirement information, wherein the session management entity can determine the PDU session requirement information according to the PDU session contract information; or the session management entity can determine the PDU session requirement information according to one or more of the PDU session policy information and the PDU session expectation information, and the PDU session contract information. The session management entity selects an anchor user plane entity within the jurisdiction of the session management entity according to the PDU session requirement information, for example: the jurisdiction of the session management entity can be a province, a city, a data center or other scopes, which is not limited in this application, and the specific jurisdiction can be configured by the operator. The session management entity determines the service base station indicated by the UE's location information according to the UE's location information, and when it is determined that the service base station indicated by the UE's location information is not connected to the above-selected anchor user plane entity, the session management function selects the first intermediate session management entity according to the UE's location information and the PDU session requirement information. It should be noted that the PDU session policy information indicates the relevant policies of the PDU session, such as QoS (Quality of Service). The PDU session expectation information indicates the session-related parameters requested by the UE, such as the PDU session expectation information including one or more of the local DNN, PDU session type and SSC mode.

[0016] In a possible implementation of the first aspect, the network device is a session management entity, and before the session management entity selects a first intermediate session management entity for a PDU session based on the location information of the UE and the PDU session requirement information, it also includes: the session management entity determines the PDU session requirement information based on the PDU session contract information; or the session management entity determines the PDU session requirement information based on one or more of the PDU session expectation information and the PDU session policy information, as well as the PDU session contract information. The PDU session policy information may come from a policy control entity of the core network. The PDU session expectation information indicates relevant parameters of the PDU session requested by the UE, and the PDU session expectation information includes one or more of the PDU session type, SSC mode, and local DNN. The session management entity determines that the local DN indicated by the local DNN included in the PDU session requirement information is not within the jurisdiction of the session management entity.

[0017] In a possible implementation of the first aspect, the network device is an access management entity, and before the network device selects a first intermediate session management entity for a PDU session according to the location information and PDU session requirement information of the UE, it also includes: the access management entity selects a session management entity, wherein the access management entity can select the session management entity according to the local DNN, network slice information and UE subscription information from the UE. The access management entity determines that the service base station indicated by the location information of the UE is not located within the jurisdiction of the session management entity, and the access management entity selects a fourth intermediate session management entity according to one or more of the local DNN, network slice information and UE subscription information from the UE and the location information of the UE, and the access management entity receives the PDU session requirement information and a reselection indication message from the session management entity, and the reselection indication message is used to instruct the access management entity to reselect a first intermediate session management entity that is different from the fourth intermediate session management entity.

[0018] In a possible implementation of the first aspect, the network device is an access management entity, and before the network device selects a first intermediate session management entity for a PDU session according to the location information and PDU session requirement information of the UE, it also includes: the access management entity selects a session management entity, wherein the access management entity may select the session management entity according to one or more of the local DNN and network slice information carried in the PDU session establishment request from the UE. The access management entity determines that the service base station indicated by the location information of the UE is not within the jurisdiction of the session management entity, the access management entity selects a fourth intermediate session management entity, receives the PDU session requirement information from the session management entity, and determines that the fourth intermediate session management entity does not meet the PDU session requirement information.

[0019] In a possible implementation of the first aspect, the network device is an access management entity, and before the PDU session requirement information network device selects a first intermediate session management entity for the PDU session based on the UE's location information and the PDU session requirement information, it also includes: when the PDU session requirement changes, the access management entity receives new PDU session requirement information and a reselection indication message from the session management entity, and the reselection indication message is used to instruct the access management entity to reselect an intermediate session management entity.

[0020] In a possible implementation of the first aspect, the network device is an access management entity, and the first intermediate session management entity currently provides services for a PDU session. When the demand for the PDU session changes, the access management entity receives new PDU session demand information from the session management entity, and the access management entity determines that the first intermediate session management entity does not meet the new PDU session demand information, and selects a target intermediate session management entity based on the UE's location information and the new PDU session demand information.

[0021] In a possible implementation manner of the first aspect, the network device is a session management entity. The session management entity determines PDU session requirement information based on PDU session contract information; or based on one or more of PDU session policy information and PDU session expectation information, as well as PDU session contract information. The session management entity determines that a fourth intermediate session management entity selected by an access management entity does not meet the PDU session requirement information. The session management entity selects a first intermediate session management entity for the PDU session based on UE location information and the PDU session requirement information. The session management entity sends identification information of the first intermediate session management entity to the access management entity, where the identification information is used to uniquely represent the identity of the first intermediate session entity. For example, the identification information of the first intermediate session management entity may be address information, location information, or ID (Identity, identity information, referred to as ID), etc.

[0022] In the second aspect, the present application provides a communication system, which includes a network device and a first intermediate session management entity. The network device may be an access management entity or a session management entity, and the network device is used to select a first intermediate session management entity for a PDU session based on the location information of the UE and the PDU session requirement information. The first intermediate session management entity is used to receive the PDU session requirement information from the network device, and select a user plane entity based on the location information of the UE and the PDU session requirement information. It should be noted that the session management entity and the first intermediate session management entity have a certain jurisdiction area, and the jurisdiction areas of the session management entity and the first intermediate session management entity do not overlap. The first intermediate session management entity is responsible for managing network elements within the jurisdiction area, such as user plane entities. The size of the jurisdiction of the first intermediate session management entity can be determined by the operator according to needs, for example, the jurisdiction of the first intermediate session management entity is a province, a city or a data center, and this application does not limit it.

[0023] In the implementation of the first aspect, the network device selects an intermediate session management entity according to the location information of the UE and the PDU session requirement information, so that the intermediate session management entity close to the UE can provide services for the PDU session and reduce the delay of data transmission. At the same time, the intermediate session management entity selects a user plane entity according to the location information of the UE and the PDU requirement information. The intermediate session management entity only manages the user plane entities within the specified range, and does not need to manage the user plane entities of the entire PDU session, thereby reducing the complexity of management.

[0024] In a possible implementation manner of the second aspect, the first intermediate session management entity is further used to receive an uplink offload policy and an uplink routing policy from a network device, configure the uplink offload policy on the BP, and configure the uplink routing policy on the UE; wherein the uplink offload policy is used to control the BP to offload according to the source address of the data packet sent by the UE, and the uplink routing policy is used to control the UE to use an IP address anchored at an anchor user plane entity or a local IP address anchored at a local anchor user plane entity as the source address of the data packet; or

[0025] The first intermediate session management entity is further used to send the IP address anchored at the anchor user plane entity and the uplink routing policy corresponding to the IP address anchored at the anchor user plane entity to the first intermediate session management entity; the IP address anchored at the anchor user plane entity is used to enable the first intermediate session management entity to generate an uplink diversion policy, and the uplink routing policy corresponding to the IP address anchored at the anchor user plane entity is used to enable the first intermediate session management entity to generate an uplink routing policy; the uplink diversion policy is used to control the BP to divert according to the source address of the data packet sent by the UE, and the uplink routing policy is used to instruct the UE to use the IP address anchored at the anchor user plane entity or the local IP address anchored at the local anchor user plane entity as the source address to send data.

[0026] In a possible implementation of the second aspect, the data transmission mode is a ULCL mode, and the first intermediate session management entity is used to select a user plane entity according to the location information of the UE and the PDU session requirement information within the jurisdiction of the first intermediate session management entity, specifically: select a local anchor user plane entity for the PDU session, and select ULCL for the PDU session. It should be noted that the session management entity also selects an anchor user plane entity for the PDU session, and the anchor user plane entity is used to connect the DN. ULCL corresponds to two transmission links: a transmission link between ULCL and the anchor user plane entity, and a transmission link between ULCL and the user plane entity. ULCL performs diversion according to the five-tuple and / or application identifier of the data packet from the UE, the five-tuple represents the source IP address, the destination IP address, the source port number, the destination port number and the protocol version, and the application identifier represents the identification information of the application program that generates the data packet on the UE. Among them, ULCL performs diversion according to a preset uplink forwarding policy, and the uplink forwarding policy represents the correspondence between the transmission link identifier and the five-tuple and / or the identifier.

[0027] In a possible implementation manner of the second aspect, the first intermediate session management entity is further configured to receive an uplink forwarding policy sent by the network device from the network device, and configure the uplink forwarding policy on the ULCL.

[0028] In a possible implementation of the second aspect, the PDU session requirement information also includes a PDU session type, and the PDU session type is an IP type. The first intermediate session management entity is also used to send one or more of the location information of the local anchor user plane entity and the location information of the local DN, as well as the local IP address of the UE to the session management entity. The local IP address of the UE represents the IP address of the anchor point allocated by the first intermediate session management entity on the local anchor user plane entity.

[0029] In a third aspect, the present application provides a device having the function of implementing the network device behavior in the above method. The function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more units corresponding to the above function.

[0030] In a possible implementation manner, the device includes: a selection unit and a transceiver unit.

[0031] The selection unit is configured to select a first intermediate session management entity for a PDU session according to location information of a user equipment UE and protocol data unit PDU session requirement information.

[0032] A transceiver unit is used to send the location information of the UE and the PDU session requirement information to the first intermediate session management entity; wherein the location information of the UE and the PDU session requirement information are used to select a user plane entity.

[0033] In another possible implementation, the network device includes: a transceiver, a memory and a processor; wherein a set of program codes are stored in the memory, and the processor is used to call the program code stored in the memory to execute any one of the session management methods in the first aspect to each possible implementation of the first aspect.

[0034] Based on the same inventive concept, since the principle and beneficial effects of the device in solving the problem can refer to the method implementation methods and the beneficial effects brought about by the above-mentioned possible terminal devices, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be repeated.

[0035] In a fourth aspect, the present application provides a session management method, comprising:

[0036] The network device selects a first intermediate session management entity for a protocol data unit PDU session according to the local network data name DNN;

[0037] The network device sends location information of a user equipment UE to the first intermediate session management entity; wherein the location information of the UE is used to select a user plane entity.

[0038] In one possible design, the network device selecting, according to the local DNN, a first intermediate session management entity for the PDU session includes:

[0039] The network device selects a first intermediate session management entity according to the local DNN and the location information of the UE; wherein, the first intermediate session management entity is selected that supports the local data network DN indicated by the local DNN and the service base station whose jurisdiction includes the location information indication of the UE.

[0040] In one possible design, the network device selecting, according to the local DNN, a first intermediate session management entity for the PDU session includes:

[0041] The network device selects an intermediate session management entity that supports the local data network DN indicated by the local DNN as the first intermediate session management entity.

[0042] In one possible design, the network device is a session management entity, and the method further includes:

[0043] The network device determines a local DNN based on information from the application function.

[0044] In one possible design, the method further includes:

[0045] The network device sends the location information of the UE to a first intermediate session management entity; wherein the location information of the UE is used to instruct the first intermediate session management entity to select a user plane entity supporting the UE location, and the user plane entity supporting the UE location is an access network interface connected to the UE.

[0046] In one possible design, the method further includes:

[0047] The network device sends the local DNN to the first intermediate session management entity; wherein the local DNN is used to instruct the first intermediate session management entity to select a local anchor user plane entity.

[0048] In one possible design, the user plane entity selected by the first intermediate session management entity supports both the local DNN and the UE location information; or

[0049] In the absence of a user plane entity that supports both the local DNN and the UE location information, the first intermediate session management entity selects a user plane entity that supports the local DNN as a local anchor user plane entity based on the local DNN, and selects a user plane entity that supports the UE location information based on the UE location information for interfacing with the access network to which the UE is connected, wherein the local anchor user plane entity is used to interface with the local DN.

[0050] In one possible design, the network device sends a data transmission mode to the first intermediate session management entity; wherein the data transmission mode is used to instruct the first intermediate session management entity to determine an uplink diversion rule.

[0051] In one possible design, if the data transmission mode is multihoming, the network device also sends the remote UE IP address to the first intermediate session management entity; wherein the remote UE IP is used to instruct the first intermediate session management entity to determine an uplink diversion rule.

[0052] In one possible design, if the data transmission mode is the uplink classifier ULCL, the network device also sends application information to the first intermediate session management entity, wherein the application information is used to instruct the first intermediate session management entity to determine an uplink diversion rule; the application information is an application identifier or at least one of the five-tuples corresponding to the application.

[0053] In one possible design, the network device sends an uplink diversion rule or an uplink forwarding rule to the first intermediate session management entity; wherein the uplink diversion rule or the uplink forwarding rule is used to instruct the first intermediate session management entity to configure the user plane entity to achieve uplink data diversion.

[0054] In one possible design, the network device sends routing information between the local anchor point and the local data network DN identified by the local DNN to the first intermediate session management entity, and the routing information is used to determine the forwarding path between the user plane entity and the local data network DN.

[0055] On the other hand, the present application provides a device, which includes: a memory and a processor; wherein a group of program codes are stored in the memory, and the processor is used to call the program codes stored in the memory to execute the fourth aspect and various possible implementation methods of the fourth aspect.

[0056] In a fifth aspect, the present application provides a device having the function of implementing the network device behavior in each possible implementation method in the fourth aspect. The function can be implemented by hardware, or by hardware executing corresponding software. The hardware or software includes one or more units corresponding to the above functions.

[0057] In a possible implementation manner, the device includes: a selection unit and a transceiver unit.

[0058] Another aspect of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores instructions, and when the computer-readable storage medium is run on a computer, the computer executes the methods described in the above aspects.

[0059] Another aspect of the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the methods described in the above aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the background technology, the drawings required for use in the embodiments of the present invention or the background technology will be described below.

[0061] Figure 1a It is a network architecture diagram provided by an embodiment of the present invention;

[0062] Figure 1b is based on Figure 1a Next-generation network architecture diagram;

[0063] Figure 2a is another network architecture diagram provided by an embodiment of the present invention;

[0064] Figure 2b is based on Figure 2a Next-generation network architecture diagram;

[0065] Figure 3 It is a flow chart of a session management method provided by an embodiment of the present invention;

[0066] Figure 4 is a flow chart of another session management method provided by an embodiment of the present invention;

[0067] Figure 5 is a flow chart of another session management method provided by an embodiment of the present invention;

[0068] Figure 6 is a flow chart of another session management method provided by an embodiment of the present invention;

[0069] Figure 7 is a schematic diagram of the structure of a device provided by an embodiment of the present invention;

[0070] Figure 8 It is a structural diagram of a network device provided by an embodiment of the present invention;

[0071] Fig. 9 is a flow chart of another session management method provided by an embodiment of the present invention;

[0072] Fig.10 It is a flowchart of another session management method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0073] The embodiments of the present invention are described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0074] Figure 1a A schematic diagram of a communication system architecture involved in an embodiment of the present invention. The communication system may be a global system for mobile communication (Global System for Mobile Communication, GSM), a code division multiple access (Code Division Multiple Access, CDMA) system, a wideband code division multiple access (Wideband Code Division Multiple Access, WCDMA) system, a world-wide microwave interconnection access (Worldwide Interoperability for Microwave Access, WiMAX) system, a long term evolution (long term evolution, LTE) system, a 5G communication system (such as a new radio (NR) system, a communication system integrating multiple communication technologies (such as a communication system integrating LTE technology and NR technology), or a subsequent evolution communication system. Figure 1a The communication system includes: an access network, an access management entity, a session management entity and a first intermediate session management entity, and may also include a policy control entity. It should be noted that: Figure 1a The form and quantity of each network element in the embodiment are only used for illustration and do not constitute a limitation to the embodiments of the present invention.

[0075] The access management entity communicates with the policy control entity, the access network and the policy control entity, the session management entity communicates with the policy control entity, the first intermediate session management entity and the anchor user plane entity, the access network communicates with the access management entity and the user plane entity, the first intermediate session management entity communicates with the session management entity and the user plane entity, and the anchor user plane entity communicates with the data network. The access management entity communicates with the session management entity.

[0076] Among them, the access management entity is mainly responsible for access and mobility management, including functions such as user authentication, switching, and location update; the session management entity is mainly responsible for session management, including functions such as the establishment, modification, and release of PDU sessions; the policy control entity is mainly responsible for the management of user measurements, including the generation of mobility-related policies and PDU session-related policies, for example: PDU session-related policies include QoS (Quality of Service, service quality, referred to as QoS) policies, charging policies, etc.; the user plane entity is mainly responsible for the forwarding of user data, and the user plane entity is divided into a common user plane entity and an anchor user plane entity. The anchor user plane function is the user plane function connected to the data network; the data network is the destination of the user's PDU session access; the first intermediate session management entity is mainly responsible for the management of user plane entities within the jurisdiction, including load sharing of user plane entities, selection of user plane entities, establishment of tunnels on user plane entities, and formulation and configuration of forwarding rules for user plane entities. The session management entity includes the establishment of user plane tunnels, the configuration of forwarding rules for user plane entities, etc. It should be noted that the first intermediate session management entity can be deployed separately or integrated in the session management entity, and this application does not limit it. The jurisdiction of the first intermediate session management entity may be determined by the operator as needed during deployment, for example, the jurisdiction of the first intermediate session management entity is a province or a city or a tracking area or a data center, which is not limited in this embodiment of the present invention.

[0077] See also Figure 1b , which is the architecture diagram of the 5G communication system. In the architecture diagram of the 5G communication system, AMF (Access Management Function, access management function, referred to as AMF) corresponds to Figure 1a The access management entity in RAN corresponds to Figure 1a The access network in SMF corresponds to Figure 1a The session management entity in the ISMF (Intermediate Session Management Function, intermediate session management entity, referred to as ISMF) corresponds to Figure 1a The first intermediate session management entity in the UPF corresponds to Figure 1a The user plane entity in the A-UPF (Anchor User Plane Function, anchor user plane function, referred to as A-UPF) corresponds to Figure 1a The anchor user plane entity in the network is DN (Data Network, DN for short).

[0078] Among them, Figure 1bAs shown in the figure, RAN and AMF communicate with each other through the N2 interface. RAN and UPF communicate with each other through the N3 interface. The two UPFs communicate with each other through the N9 interface. Figure 1b The UPF and A-UPF in the DN can communicate with each other through the N9 interface. The ISMF and UPF can communicate with each other through the N4 interface, and the SMF and A-UPF can also communicate with each other through the N4 interface. The A-UPF and DN can communicate with each other through the N6 interface. The SMF and PCF can communicate with each other through the N7 interface. The SMF and ISMF can communicate with each other through the N16 interface. The SMF and AMF can communicate with each other through the N11 interface. The AMF and PCF can communicate with each other through the N15 interface.

[0079] See also Figure 2a , is another structural diagram of a communication system provided in an embodiment of the present invention, Figure 2a The structure of the communication system shown and Figure 1a The only difference in the structure of the communication system is that there is no intercommunication between the access management entity and the session management entity, and the access management entity intercommunications with the intermediate session management entity. Figure 2a The functions of each network element can be referred to Figure 1a The description in will not be repeated here.

[0080] Figure 2b Another architecture diagram of a 5G communication system, in which: Figure 2b The network elements and Figure 2a The corresponding relationship between network elements in can be referred to Figure 1b and Figure 1a The correspondence between the network elements in will not be repeated here. Figure 2b The structure diagram of the communication system and Figure 1b The only difference between the structural diagram of the communication system is that AMF and SMF do not communicate with each other, and AMF and ISMF communicate with each other through the N11 interface.

[0081] Among them, the access network in this application can also be referred to as a base station device, which is a device deployed in a wireless access network to provide wireless communication functions, including but not limited to: base stations (for example: BTS (Base Transceiver Station, BTS), NodeB (NodeB, NB), Evolutional Node B (Evolutional Node B, eNB or eNodeB), NR system transmission node or transceiver point (transmission reception point, TRP or TP) or next generation node B (generation nodeB, gNB), base stations or network equipment in future communication networks), relay stations, access points, vehicle-mounted devices, wearable devices, Wireless-Fidelity (Wireless-Fidelity, Wi-Fi) sites, wireless backhaul nodes, small stations, micro stations, etc.

[0082] In the current user plane entity management method, one PDU session may correspond to multiple user plane entities, and different user plane entities may be located in different positions. The session management entity needs to manage user plane entities in different positions at the same time, which makes the management process more complicated.

[0083] In view of this, based on Figure 1a or Figure 2a The embodiment of the present invention provides a communication system including: a network device and a first intermediate session management entity.

[0084] The network device is used to select a first intermediate session management entity for a PDU session according to the location information of the user equipment UE and the protocol data unit PDU session requirement information. The network device in this embodiment is an access management entity or a session management entity. The first intermediate session management entity is used to receive the PDU session requirement information from the network device, and select a user plane entity according to the location information of the UE and the PDU session requirement information.

[0085] Optional, based on Figure 1a or Figure 2a The network architecture of the PDU session requires information including the data transmission mode and the local data network name DNN.

[0086] Optional, based on Figure 1a or Figure 2a The network architecture of the communication system further includes an anchor user plane entity, a local anchor user plane entity (not shown in the figure), a serving base station and a BP (not shown in the figure), the serving base station is an access network device, and the data transmission mode is a multi-homing Mutilhoming mode;

[0087] The first intermediate session management entity is used to select a user plane entity according to the UE's location information and PDU session requirement information within the jurisdiction of the first intermediate session management entity, specifically: selecting a local anchor user plane entity for the PDU session, and selecting a branch point BP for the PDU session; wherein BP is used to divert data packets sent by the UE, the local anchor user plane entity is connected to the local data network DN indicated by the local DNN included in the PDU session requirement information, and BP is connected to the service base station indicated by the UE's location information.

[0088] Optional, based on Figure 1a or Figure 2a The first intermediate session management entity is further used to receive an uplink offload strategy and an uplink routing strategy from a network device, configure the uplink offload strategy to the BP, and configure the uplink routing strategy to the UE; wherein the uplink offload strategy is used to control the BP to offload according to the source address of the data packet sent by the UE, and the uplink routing strategy is used to control the UE to use the IP address anchored in the anchor user plane entity or the local IP address anchored in the local anchor user plane entity as the source address of the data packet; or

[0089] The first intermediate session management entity is further used to send the IP address anchored at the anchor user plane entity and the uplink routing policy corresponding to the IP address anchored at the anchor user plane entity to the first intermediate session management entity; the IP address anchored at the anchor user plane entity is used to enable the first intermediate session management entity to generate an uplink diversion policy, and the uplink routing policy corresponding to the IP address anchored at the anchor user plane entity is used to enable the first intermediate session management entity to generate the uplink routing policy; the uplink diversion policy is used to control the BP to divert according to the source address of the data packet sent by the UE, and the uplink routing policy is used to instruct the UE to use the IP address anchored at the anchor user plane entity or the local IP address anchored at the local anchor user plane entity as the source address to send data.

[0090] Optional, based on Figure 1a or Figure 2a The network architecture of the communication system also includes ULCL and local DN (not shown in the figure), the data transmission mode is ULCL mode, the first intermediate session management entity is used to select a user plane entity according to the UE's location information and PDU session requirement information within the jurisdiction of the first intermediate session management entity, specifically: select a local anchor user plane entity for the PDU session, and select an uplink classifier ULCL for the PDU session; wherein the ULCL is used to divert the application identifier and / five-tuple of the data packet sent by the UE, the local anchor user plane entity is connected to the local DN indicated by the local DNN, and the ULCL is connected to the serving base station indicated by the UE's location information.

[0091] Optional, based on Figure 1a or Figure 2a In the network architecture, the first intermediate session management entity is further used to receive an uplink forwarding policy from a network device and configure the uplink forwarding policy on the ULCL; wherein the uplink forwarding policy is used to control the ULCL to perform traffic diversion according to one or more of the quintuple and the application identifier.

[0092] Optional, based on Figure 1a or Figure 2a The network architecture, the PDU session requirement information also includes a PDU session type, and the PDU session type is an IP type;

[0093] The first intermediate session management entity is further used to send one or more of the location information of the local anchor user plane entity and the location information of the local DN, and the local IP address of the UE to the session management entity.

[0094] Optional, based on Figure 1a or Figure 2a The network architecture, the PDU session requirement information includes: one or more of session and service continuity SSC mode and PDU session type.

[0095] Optional, based on Figure 1a or Figure 2a The network architecture of the present invention is that the network device is used to select the first intermediate session management entity for the PDU session according to the location information of the UE and the protocol data unit PDU session requirement information: the intermediate session management entity that satisfies the PDU session requirement information and whose jurisdiction includes the service base station indicated by the location information of the UE is selected as the first intermediate session management entity. The network device can be an access management entity or a session management entity.

[0096] Optional, based on Figure 1a or Figure 2a The network architecture is further configured to select a second intermediate session management entity that meets the PDU session requirement information and a third intermediate session management entity that meets the UE location information indication if it is determined that there is no intermediate session management entity that meets the PDU session requirement information and has a jurisdiction that includes the UE location information indication. The network device in this embodiment may be an access management entity or a session management entity.

[0097] Optional, based on Figure 1a or Figure 2aIn the network architecture, the network device is used to select a first intermediate session management entity for the PDU session according to the location information of the UE and the protocol data unit PDU session requirement information, specifically selecting a serving base station with a jurisdiction including the location information indication of the UE and a local DN that satisfies the local DNN indication included in the PDU session requirement information, and an intermediate session management entity that supports the data transmission mode as the first intermediate session management entity. The network device in this embodiment can be an access management entity or a session management entity.

[0098] Optionally, the network device is further configured to select a second intermediate session management entity whose jurisdiction includes the service base station indicated by the location information of the UE, a local DN indicated by the local DNN, and an intermediate session management entity supporting the data transmission mode if it is determined that there is no service base station whose jurisdiction includes the service base station indicated by the location information of the UE, and a third intermediate session management entity whose jurisdiction includes the local DN indicated by the local DNN and supports the data transmission mode. The network device in this embodiment may be an access management entity or a session management entity.

[0099] Optional, based on Figure 1a The network architecture of the communication system further includes an access management entity and a policy management entity, and the network device is a session management entity; the access management entity is used to select the session management entity. The network device is also used to determine the PDU session requirement information according to the PDU session contract information; or determine the PDU session requirement information according to one or more of the PDU session policy information and the PDU session expectation information, as well as the PDU session contract information; select an anchor user plane entity for the PDU session according to the PDU session requirement information; and determine that the anchor user plane entity is not connected to the service base station indicated by the location information of the UE. The network device obtains the PDU session requirement information from the policy management entity.

[0100] Optional, based on Figure 1a The network architecture includes an access management entity, and the network device is a session management entity.

[0101] The access management entity is used to select the session management entity.

[0102] The session management entity is also used to: determine PDU session requirement information based on PDU session contract information; or determine PDU session requirement information based on one or more of PDU session policy information and PDU session expectation information, as well as PDU session contract information; and determine that the jurisdiction of the session management entity does not include the local DN indicated by the local DNN.

[0103] Optional, based on Figure 2a The network architecture, the communication system also includes an access management entity, and the network device is a session management entity;

[0104] The access management entity is used to select a session management entity, and when the jurisdiction of the session management entity does not include the serving base station indicated by the location information of the UE, select a fourth intermediate session management entity ( Figure 2a The session management entity is further used to: determine the PDU session requirement information according to the PDU session contract information, or one or more of the PDU session policy information and the PDU session expectation information and the PDU session contract information, and determine that the fourth intermediate session management entity does not meet the PDU session requirement information; the session management entity is further used to send the identification information of the first intermediate session management entity to the access management entity.

[0105] Optional, based on Figure 2a The network architecture of the communication system further includes a session management entity, and the network device is an access management entity. The session management entity is used to determine the PDU session requirement information according to the PDU session contract information; or determine the PDU session requirement information according to one or more of the PDU session policy information and the PDU session expectation information, as well as the PDU session contract information; determine that the fourth intermediate session management entity selected by the access management entity does not meet the PDU session requirement information, and send the PDU session requirement information and a reselection indication message to the access management entity, and the reselection indication message is used to instruct the access management entity to select the first intermediate session management entity. The access management entity is also used to select a session management entity, and select a fourth intermediate session management entity when the jurisdiction of the session management entity does not include the service base station indicated by the UE's location information; receive the PDU session requirement information and the reselection indication message from the session management entity.

[0106] Optional, based on Figure 2a The network architecture of the communication system further includes a session management entity, and the network device is an access management entity. The session management entity is used to determine the PDU session requirement information according to the PDU session contract information; or according to one or more of the PDU session policy information and the PDU session expectation information, and the PDU session contract information, and send the PDU session requirement information to the access management entity. The access management entity is also used to select a session management entity, and when the jurisdiction of the session management entity does not include the serving base station indicated by the UE's location information, select a fourth intermediate session management entity ( Figure 2a (not shown), it is determined that the fourth intermediate session management entity does not meet the PDU session requirement information from the session management entity.

[0107] By implementing the embodiment of the present invention, an intermediate session management entity is selected according to the location information of the UE and the PDU session requirement information, so that the intermediate session management entity close to the UE can provide services for the PDU session, reducing the delay of data transmission. At the same time, the intermediate session management entity selects the user plane entity according to the location information of the UE and the PDU requirement information. The intermediate session management entity only manages the user plane entity within the specified range, and does not need to manage the user plane entity of the entire PDU session, thereby reducing the complexity of management.

[0108] See also Figure 3 , is a flow chart of a session management method provided by an embodiment of the present invention. In this embodiment, the session management method is based on Figure 1a The network architecture is a network device that is an access management entity. The method includes but is not limited to the following steps:

[0109] S301. User equipment sends a PDU session establishment request to an access management entity, and the access management entity receives the PDU session establishment request sent by the user equipment.

[0110] Optionally, the user equipment sends a PDU session establishment request to the access management entity through its service base station (not shown in the figure). The PDU session establishment request is used to create a PDU session. The PDU session establishment request carries PDU session expectation information and UE location information. The PDU session expectation information is the relevant parameter requirements of the PDU session requested by the user equipment. The PDU session expectation information includes one or more of the local DNN, network slice information, PDU session type, and SSC mode. The network slice information is used to describe the relevant attributes of the network slice, for example: the network slice information includes one or more of the network slice type, network slice identifier, and network slice location. Among them, the PDU session expectation information is a NAS (Non-Access Stratum) message. The UE's location information indicates the UE's location in the access network. The UE's location information can be the identifier of the UE's service cell or the identifier of the UE's service base station or the UE's tracking area identifier.

[0111] S302: The access management entity selects a session management entity.

[0112] Optionally, the access management entity obtains the resolvable parameters carried in the PDU session establishment request, and the resolvable parameters of the access management entity include the UE location information, local DNN and network slice information, and the access management entity selects the session management entity according to one or more of the UE location information, local DNN and network slice information. Among them, the access management entity can use one or more of the UE location information, local DNN and network slice information as input parameters, and query in a database configured locally according to the input parameters or in NRF (Network Function Repository Function, Network Function Storage Function, referred to as NRF) to obtain the identifier of the selected session management entity.

[0113] S303: The access management entity sends a PDU session establishment request to the session management entity.

[0114] S304: The session management entity receives the PDU session request message sent by the access management entity, selects an anchor user plane entity, and determines that a first intermediate session management entity needs to be selected.

[0115] The session management entity selects the first intermediate session management entity according to the location information of the UE and the PDU session requirement information.

[0116] Optionally, the session management entity parses the UE location information and PDU session expectation information carried in the PDU session management request, obtains the PDU session contract information from the UDM (Unified Data Management, referred to as UDM), and obtains the PDU session policy information from the policy control entity, for example: the PDU session policy information includes QoS (Quality of Service, referred to as QoS) policy and billing policy, etc. The session management entity can determine the PDU session requirement information based on the PDU session contract information; or the session management entity determines the PDU session requirement information based on one or more of the PDU session expectation information and the PDU session policy information, as well as the PDU session contract information. The PDU session requirement information indicates the relevant parameter requirements of the PDU session that the network side can accept. The PDU session requirement information includes the PDU session type, SSC mode, local DNN and data transmission mode, and the transmission mode is Mutilhoming mode or ULCL mode. The session management entity is pre-set with a jurisdiction scope. The session management entity can only manage network elements within the scope of the relationship (for example, base stations, user plane entities, etc.). The jurisdiction scope can be determined by the operator during deployment, and the size of the jurisdiction scope is not limited. For example, the jurisdiction scope of the session management entity is a province, a city, or a data center. The session management entity selects an anchor user plane entity, which is used to interface with the data network.

[0117] The session management entity determines whether to select the first intermediate session management entity. The determination method may be:

[0118] a. The session management entity determines whether the serving base station indicated by the UE's location information is connected to the selected anchor user plane entity. If not, the session management entity selects a first intermediate session management entity according to the UE's location information and the PDU session requirement information.

[0119] b. When the PDU session requirement information includes the local DNN and the transmission mode, the session management entity determines whether its jurisdiction includes the data network indicated by the local DNN. If not, the session management entity selects the first intermediate session management entity based on the UE's location information and the PDU session requirement information.

[0120] Optionally, the method for the session management entity to select the first intermediate session management entity may be:

[0121] The session management entity uses an intermediate session management entity that meets the PDU session requirement information and has a jurisdiction that includes a serving base station indicated by the UE's location information as the first intermediate session management entity.

[0122] Optionally, when the session management entity determines that there is no intermediate session management entity that meets the PDU session requirement information and whose jurisdiction includes the service base station indicated by the UE's location information, it selects a second intermediate session management entity that meets the PDU session requirement information, and selects a third intermediate session management entity whose jurisdiction includes the service base station indicated by the UE's location information. The second intermediate session management entity and the third intermediate session management entity provide services for the PDU session at the same time.

[0123] When the transmission mode and the local DNN are included in the PDU session requirement information, the session management entity will support the DN indicated by the local DNN, and the intermediate session management entity that supports the transmission mode will serve as the first intermediate session management entity.

[0124] Optionally, the session management entity determines that there is no intermediate session management entity whose jurisdiction includes the service base station indicated by the location information of the UE and the DN indicated by the local DNN, and which supports the transmission mode. The session management entity selects a second intermediate session management entity whose jurisdiction includes the service base station indicated by the location information of the UE, and selects a third intermediate session management entity whose coverage includes the local DN indicated by the local DNN and supports the transmission mode. The second intermediate session management entity and the third intermediate session management entity provide services for the PDU session at the same time.

[0125] S305. The session management entity sends a PDU session establishment request to the first intermediate session management entity.

[0126] The PDU session establishment request carries the UE location information and the PDU session requirement information. The session management entity may send the UE location information and the PDU session requirement information to the first intermediate session management entity through the PDU session establishment request.

[0127] Optionally, when the data transmission mode is Mutilhoming mode, the session management entity sends the uplink diversion strategy and the uplink routing strategy to the first intermediate session management entity, the uplink diversion strategy is used to control the branch point BP anchored by the UE to divert according to the source address of the data packet sent by the UE, and the uplink routing strategy is used to control the UE to use the IP address anchored at the anchor user plane entity or the local IP address anchored at the local anchor user plane entity as the source address of the data packet.

[0128] Optionally, the data transmission mode is Mutilhoming mode, and the session management entity sends the IP address anchored at the anchor user plane entity and the uplink routing policy corresponding to the IP address anchored at the anchor user plane entity to the first intermediate session management entity; the IP address anchored at the anchor user plane entity is used to enable the first intermediate session management entity to generate an uplink diversion policy, and the uplink routing policy is used to enable the first intermediate session management entity to generate the uplink routing policy; the uplink routing policy is used to instruct the UE to use the IP address anchored at the anchor user plane entity or the local IP address anchored at the local anchor user plane entity as the source address to send data.

[0129] Optionally, the data transmission mode is an uplink classifier ULCL mode, and the session management entity sends an uplink forwarding policy to the first intermediate session management entity, and the uplink forwarding policy is used to control the uplink classifier ULCL anchored by the UE to forward according to one or more of the five-tuple and application identifier of the data packet sent by the UE.

[0130] S306: The first intermediate session management entity receives a PDU session establishment request from the session management entity, and the first intermediate session management entity selects a BP and a local anchor user plane entity. S306 is an optional step.

[0131] Optionally, this embodiment takes the Mutilhoming mode as an example, and the first intermediate session management entity parses the UE location information and PDU session requirement information in the PDU session establishment request. The first intermediate session management entity selects a local anchor user plane entity for the PDU session, and selects a branch point BP for the PDU session; wherein BP is used to divert data packets sent by the UE, the local anchor user plane entity is connected to the local data network DN indicated by the local DNN included in the PDU session requirement information, and BP is connected to the service base station indicated by the UE's location information.

[0132] Optionally, when the transmission mode is ULCL mode, the first intermediate session management entity selects a local anchor user plane entity for the PDU session, and selects an uplink classifier ULCL for the PDU session; wherein the ULCL is used to divert the application identifier and / or five-tuple of the data packet sent by the UE, the local anchor user plane entity is connected to the local DN indicated by the local DNN, and the ULCL is connected to the service base station indicated by the location information of the UE.

[0133] Optionally, when the jurisdiction of the first intermediate session management entity includes the serving base station of the UE, the local anchor user plane entity, the user plane entity connected to the serving base station and the BP / ULCL may be the same user plane entity.

[0134] S307: The first intermediate session management entity sends an N4 message to the selected BP. S307 is an optional step.

[0135] The N4 message in this step indicates a message transmitted through the N4 interface, the first intermediate session management entity allocates N3 uplink tunnel information and N9 downlink tunnel information, the N3 uplink tunnel information indicates the identification information of the tunnel between the BP and the serving base station of the user equipment, the N9 downlink tunnel information indicates the identification information of the tunnel between the BP and the local anchor user plane entity, and the identification information of the tunnel between the BP and the anchor user plane entity. The first intermediate session management entity sends the N3 uplink tunnel information and the N9 downlink tunnel information to the BP through the N4 message, the BP receives the N3 uplink tunnel information and the N9 downlink tunnel information from the first intermediate session management entity, and creates the N3 tunnel and the N9 tunnel on the local path.

[0136] It should be noted that when the transmission mode is ULCL mode, the first intermediate session management entity sends an N4 message to the ULCL, the N4 message includes N3 uplink tunnel information and N9 downlink tunnel information, and the ULCL receives the N4 message and creates the N3 tunnel and the N9 tunnel.

[0137] S308: The first intermediate session management entity sends an N4 message to the selected local anchor user plane entity. S308 is an optional step.

[0138] Among them, the first intermediate session management entity allocates a local IP address and N9 uplink and downlink tunnel information to the local anchor user plane entity, and the first intermediate session management entity sends the local IP address and N9 uplink and downlink tunnel information to the local anchor user plane entity through an N4 message. The anchor user plane entity receives the N4 message and creates an N9 tunnel for the local path.

[0139] S309: The first intermediate session management entity sends a response message to the session management entity. S309 is an optional step.

[0140] The response message may carry the N9 downlink tunnel information of the BP. In addition, when the session type of the PDU session is an IP type, the first intermediate session management entity may also send the location information and / or the local IP address of the local anchor user plane entity to the session management entity.

[0141] S310: The session management entity sends an N4 message to the anchor user plane entity. S310 is an optional step.

[0142] Among them, the session management entity allocates an IP address and N9 uplink and downlink tunnel information of the anchor user plane entity to the PDU session, sends the allocated IP address and N9 uplink and downlink tunnel information to the anchor user plane entity through an N4 message, and the anchor user plane entity receives the N4 message and creates an N9 tunnel with the BP.

[0143] S311, allocating radio resources for the PDU session. S311 is an optional step.

[0144] The session management entity requests the access network (not shown in the figure) to create a user plane tunnel and allocate air interface resources for the PDU session, and configure the QoS policy of the PDU session to the access network. The access network sends the N3 downlink tunnel information to the session management entity.

[0145] S312: The session management entity sends a PDU session update request to the first intermediate session management entity. S312 is an optional step.

[0146] The session management entity sends the N3 downlink tunnel information to the first intermediate session management entity. When the session type of the PDU session is an IP type, the session management entity may also send the IP address allocated by the session management entity to the first intermediate session management entity.

[0147] S313: The first intermediate session management entity sends a PDU session update request to the BP. S313 is an optional step.

[0148] The PDU session update request includes N3 downlink tunnel information, N9 uplink tunnel information of the anchor user plane entity, and N9 uplink tunnel information of the local anchor user plane entity. BP receives the PDU session update request and updates the PDU session. If the uplink diversion strategy needs to be updated, the PDU session update request also includes the updated uplink diversion strategy.

[0149] S314: The first intermediate session management entity sends a response message to the session management entity, wherein the response message indicates that the update of the PDU session is completed. S314 is an optional step.

[0150] S315: The session management entity receives a response message from the first intermediate session management entity, and sends a response message to the access management entity. S315 is an optional step.

[0151] S316: The first intermediate session management entity sends a routing advertisement to the user equipment through the local anchor user plane entity. S316 is an optional step.

[0152] Among them, the transmission mode in this step is Mutilhoming mode, the routing announcement carries the uplink routing policy and the IP address assigned by the session management entity, and the uplink routing policy is used to control the UE to select the IP address assigned by the session management entity or the local IP address assigned by the first intermediate session management entity as the source address when sending a data packet.

[0153] It should be noted that when the user plane entity receives downlink data, the user plane entity can be any type of user plane entity. The user plane entity determines that there is no downlink N3 tunnel information, and the user plane entity sends a downlink data notification to the first intermediate session management entity. The first intermediate session management entity forwards the received downlink data notification to the session management entity, and the session management entity triggers the paging process. After the session management entity receives the downlink N3 tunnel information sent by the UE's service base station, it sends a PDU session update request to the first intermediate session management entity. The first intermediate session management entity receives the PDU session update request, obtains the downlink N3 tunnel information from the PDU session update request, and the first intermediate session management entity notifies the user plane entity of the downlink N3 tunnel information. The user plane entity receives the downlink N3 tunnel information and then sends uplink data.

[0154] In implementing the embodiments of the present invention, the session management entity and the intermediate session management entity are only responsible for managing the user plane entities within their jurisdiction, and do not need to manage all user plane entities in the entire PDU session, thereby reducing the number of messages between the user plane entities and alleviating the workload.

[0155] See also Figure 4 , is a flow chart of a session management method provided by an embodiment of the present invention. In this embodiment, the architecture Figure 1a The handover process of FIG. 1 is described in detail. Before the handover, the source access network of the UE serves the base station (not shown in the figure), the source intermediate session management entity (the first intermediate session management entity), the source user plane entity and the anchor user plane entity provide services for the PDU session. When the handover occurs, the method includes but is not limited to the following steps:

[0156] S401: The target access network sends a path switching request to a session management entity through an access management entity. S401 is an optional step.

[0157] Among them, after the UE switches from the source access network to the target access network, the target access network sends a path switching request to the session management entity through the access management entity. The path switching request carries the UE's location information. The UE's location information can be the identifier of the base station where the UE resides or the identifier of the cell where the UE resides.

[0158] S402: The session management entity receives a path switching request, determines according to the location information of the UE that the UE is not within the jurisdiction of the first intermediate session management entity, and selects a target intermediate session management entity.

[0159] Among them, the session management entity stores the PDU session requirement information of the PDU session. The session management entity selects the target intermediate session management entity according to the UE location information and the PDU session requirement information. The specific selection process can be referred to Figure 3 The description of S304 is not repeated here.

[0160] S403: The session management entity sends a PDU session establishment request to the target intermediate session management entity.

[0161] The PDU session establishment request carries the UE location information and PDU session requirement information.

[0162] S404: The target intermediate session management entity receives the PDU session establishment request and selects a target user plane entity according to the UE's location information and the PDU session requirement information. S404 is an optional step. The specific process of the target intermediate session management entity selecting the target user plane entity according to the UE's location information and the PDU session requirement information can be found in Figure 3 The description of S306 is not repeated here.

[0163] It should be noted that the target intermediate session management entity sends an N4 message to the selected target user plane entity, the target user plane entity receives the N4 message from the target intermediate session management entity, the target user plane entity creates an N9 tunnel with the anchor user plane entity, and creates an N3 tunnel with the target access network. The target intermediate session management entity sends a response message to the session management entity, the response message carries the identification information of the N3 tunnel and the identification information of the N9 tunnel created above, the session management entity receives the identification information of the N3 tunnel and the identification information of the N9 tunnel sent from the intermediate session management entity, and updates the identification information of the N9 tunnel of the anchor user plane entity. The session management entity sends a switching response message to the access management entity, the access management entity receives the switching response message from the session management entity, and learns that the tunnel update process is completed.

[0164] In implementing the embodiments of the present invention, when the location of the UE is updated, the session management entity selects the intermediate session management entity and the user plane entity close to the UE to provide services for the UE, thereby reducing the delay during data transmission. At the same time, the session management entity and the intermediate session management entity are only responsible for managing the user plane entities within their jurisdiction, and do not need to manage all user plane entities in the entire PDU session, thereby reducing the number of messages between the user plane entities and alleviating the workload.

[0165] See also Figure 5 , is a flow chart of a session management method provided by an embodiment of the present invention, and the embodiment of the present invention is applicable to Figure 2a The method includes but is not limited to:

[0166] S501. User equipment sends a PDU session establishment request to an access management entity. S501 is an optional step.

[0167] Among them, the user equipment sends a PDU session establishment request to the access management entity through its service base station (not shown in the figure). The PDU session establishment request is used to create a PDU session. The PDU session establishment request carries PDU session expectation information and UE location information. The PDU session expectation information is the relevant parameter requirements of the PDU session requested by the user equipment. The PDU session expectation information includes one or more of the local DNN, network slice information, PDU session type, and SSC mode. The network slice information is used to describe the relevant attributes of the network slice, for example: the network slice information includes one or more of the network slice type, network slice identifier, and network slice location. Among them, the PDU session expectation information is a NAS (Non-Access Stratum) message. The UE's location information indicates the UE's location in the access network. The UE's location information can be the identifier of the UE's service cell or the identifier of the UE's service base station.

[0168] S502: The access management entity receives a PDU session establishment request from the UE, selects a session management entity, and determines that a fourth session management entity needs to be selected. S502 is an optional step.

[0169] Among them, the access management entity obtains the resolvable parameters carried in the PDU session establishment request, and the resolvable parameters of the access management entity include the location information of the UE, the local DNN and the network slice information. The access management entity selects the session management entity according to one or more of the location information of the UE, the local DNN and the network slice information. Among them, the access management entity can use one or more of the location information of the UE, the local DNN and the network slice information as input parameters, and query the database configured locally according to the input parameters or in the NRF (Network Function Repository Function, Network Function Repository Function, referred to as NRF) to obtain the identifier of the selected session management entity. The access management entity determines whether the jurisdiction of the selected session management entity includes the service base station indicated by the location information of the UE. If not, the access management entity determines that a fourth intermediate session management entity needs to be preliminarily selected. The method for the access management entity to select the fourth intermediate session management entity may be: selecting the fourth intermediate session management entity according to one or more of the location information of the UE, the local DNN and the network slice information.

[0170] S503. The access management entity sends a PDU session establishment request to the fourth intermediate session management entity. The PDU session establishment request also carries identification information of the session management entity. S503 is an optional step. The identification information of the first intermediate session management entity may be address information, location information or ID (Identity, identity information, referred to as ID).

[0171] S504: The fourth intermediate session management entity receives the PDU session establishment request from the access management entity and selects a user plane entity. S504 is an optional step.

[0172] Among them, the fourth intermediate session management entity obtains the PDU session expectation information, the UE location information and the identification information of the session management entity carried in the PDU session request message, and the fourth intermediate session management entity selects a user plane entity (not shown in the figure) according to the PDU session expectation information and the UE location information. The method for selecting the user plane entity can be: the fourth intermediate session management entity selects a user plane entity within the jurisdiction, and the selected user plane entity is connected to the service base station of the UE. The fourth intermediate session management entity sends an N4 message to the selected user plane entity, and the user plane entity receives the N4 message and creates an N3 downlink tunnel and an N9 uplink tunnel.

[0173] S505: The fourth intermediate session management entity sends a PDU session establishment request to the session management entity. S505 is an optional step.

[0174] S506: The session management entity receives the PDU session establishment request from the fourth intermediate session management entity, selects an anchor user plane entity, and determines that the first intermediate session management entity needs to be selected.

[0175] Among them, the session management entity obtains the PDU session contract information from the UDM and obtains the PDU session policy information from the policy control entity. The session management entity can determine the PDU session requirement information based on the PDU session contract information; or the session management entity determines the PDU session requirement information based on one or more of the PDU session expectation information and the PDU session policy information, as well as the PDU session contract information. The PDU session requirement information indicates the relevant parameter requirements of the PDU session that the network side can accept. The PDU session requirement information includes the PDU session type, SSC mode, local DNN and data transmission mode, and the transmission mode is Mutilhoming mode or ULCL mode. The session management entity is pre-set with a jurisdiction. The session management entity can only manage network elements within the relationship scope (for example: base stations, user plane entities, etc.). The jurisdiction can be determined by the operator during deployment, and the size of the jurisdiction is not limited. For example, the jurisdiction of the session management entity is a province, a city or a data center. The session management entity selects an anchor user plane entity, and the anchor user plane entity is used to interface with the data network.

[0176] Among them, the session management entity determines whether the fourth intermediate session management entity meets the PDU session requirement information. If not, the session management entity selects the first intermediate session management entity according to the UE location information and the PDU session requirement information. The method for determining whether to select the first intermediate session management entity and selecting the first intermediate session management entity can refer to Figure 3 The description of S304 in will not be repeated here.

[0177] After selecting the first intermediate session management entity, the session management entity notifies the first intermediate session management entity of the UE's location information and PDU session requirement information. Optionally, the session management entity notifying the first intermediate session management entity of the UE's location information and PDU session requirement information may be a process from S507 to S509.

[0178] S507: The session management entity sends a response message to the fourth intermediate session management entity.

[0179] Since the first intermediate session entity is reselected in S506, the response message carries PDU session requirement information, UE location information and identification information of the first intermediate session management entity. The identification information of the first intermediate session management entity may be address information, location information or ID (Identity, ID for short).

[0180] S508. The fourth intermediate session management entity receives a response message from the session management entity, and sends a response message to the access management entity.

[0181] The fourth intermediate session management entity deletes the local session, and the response message carries the identification information of the first intermediate session management entity and the PDU session requirement information.

[0182] S509: The access management entity receives a response message from the fourth intermediate session management entity, and sends a PDU session establishment request to the first intermediate session management entity, wherein the PDU session establishment request carries the UE location information and PDU session requirement information.

[0183] S510: The first intermediate session management entity receives a PDU session establishment request from the access management entity, obtains the location information of the UE and the PDU session requirement information, and selects a user plane entity according to the location information of the UE and the PDU session requirement information. The process of selecting the user plane entity may refer to Figure 3 The description of S306 is not repeated here.

[0184] The first intermediate session management entity sends an N4 message to the selected user plane entity, the user plane entity receives the N4 message, and creates a local session according to the instruction of the N4 message. The first intermediate session management entity sends a PDU session establishment request to the session management entity. The session management entity sends the N4 message to the anchor user plane entity, the anchor user plane entity receives the N4 message from the session management entity, and creates a session according to the instruction of the N4 message.

[0185] Optionally, after S509, the first intermediate session management entity sends a PDU session establishment request to the session management entity.

[0186] The session management entity sends an N4 message to the selected anchor user plane entity. The anchor user plane entity receives the N4 message and creates a local session. After the anchor user plane entity successfully creates the local session, it sends a response message to the session management entity. The response message indicates that the local session is successfully created. The session management entity receives the response message and sends the response message to the first intermediate session management entity. The first intermediate session management entity receives the response message from the session management entity. The first intermediate session management entity sends the received response message to the access management entity. The access management entity receives the response message from the first intermediate session management entity.

[0187] Optionally, when the session management entity determines that the first intermediate session management entity needs to be selected, it sends a reselection indication message and PDU session requirement information to the access management entity. The access management entity receives the reselection indication message and PDU session requirement information from the session management entity, and selects the first intermediate session management entity according to the UE location information and the PDU session requirement information. The selection method can refer to Figure 3 The description of S304 is not repeated here.

[0188] In another optional implementation, the access management entity receives PDU session requirement information from the session management entity, and when the access management entity determines that it is necessary to select a first intermediate session management entity, the access management entity selects the first intermediate session management entity based on the UE location information and the PDU session requirement information.

[0189] Optionally, when the session management entity determines that there is no need to select the first intermediate session management entity, the session management entity sends an N4 message to the selected anchor user plane entity, and the anchor user plane entity receives the N4 message and creates an N3 tunnel and an N9 tunnel. The session management entity sends a response message to the fourth intermediate session management entity, and the response message carries the PDU session requirement information and the UE location information. The fourth intermediate session management entity receives the response message from the session management entity and obtains the PDU session requirement information. The fourth intermediate session management entity determines whether the user plane entity selected in S504 meets the PDU session requirement information. If not, the fourth intermediate session management entity reselects the user plane entity based on the UE location information and the PDU session requirement information. The selection method can refer to Figure 3 The description of S306 is not repeated here.

[0190] In implementing the embodiments of the present invention, the session management entity and the intermediate session management entity are only responsible for managing the user plane entities within their jurisdiction, and do not need to manage all user plane entities in the entire PDU session, thereby reducing the number of messages between the user plane entities and alleviating the workload.

[0191] See also Figure 6 , which is a flow chart of a session management method provided in an embodiment of the present invention. In this embodiment, it is an explanation of the switching process of architecture 2a. Before the switching, the source access network of the UE provides services for the PDU session for the serving base station (not shown in the figure), the source intermediate session management entity (the first intermediate session management entity), the source user plane entity and the anchor user plane entity.

[0192] When the switching occurs, the method includes but is not limited to the following steps:

[0193] S601: The target access network sends a path switching request to an access management entity, wherein the path switching request carries location information of the UE.

[0194] S602: The access management entity receives a path switching request from the target access network, determines that the UE is not within the jurisdiction of the first intermediate session management entity, and selects a target intermediate session management entity. The method for selecting the target intermediate session management entity can refer to Figure 4 Description of S402.

[0195] S603: The access management entity sends a session establishment request to the target intermediate session management entity.

[0196] S604: The target intermediate session management entity receives the session establishment request from the access management entity and selects a target user plane entity. The method for selecting the target user plane entity can refer to Figure 4 S604 is an optional step.

[0197] Optionally, the access management entity receives new PDU session requirement information sent from the session management entity, and the session management entity sends the new PDU session requirement information to the access management entity through the first intermediate session management entity. The access management entity determines whether the first intermediate session management entity meets the new PDU session requirement information. If not, the access management entity selects a target intermediate session management entity. The method for selecting the target intermediate session management entity can refer to Figure 4 Description of S402.

[0198] In implementing the embodiments of the present invention, the access management entity selects the intermediate session management entity and the user plane entity close to the UE to provide services for the UE, thereby reducing the delay during data transmission. Meanwhile, the session management entity and the intermediate session management entity are only responsible for managing the user plane entities within their jurisdiction, and do not need to manage all the user plane entities in the entire PDU session, thereby reducing the number of messages between the user plane entities and alleviating the workload.

[0199] See also Fig. 9 , is a flow chart of a session management method provided by an embodiment of the present invention. In this embodiment, the session management method is based on Figure 1a The network architecture of this embodiment assumes that the UE has established a PDU session, the PDU session is served by the session management entity, and the user plane of the PDU session is served by the anchor user plane entity. The method includes but is not limited to the following steps:

[0200] S901: A session management entity selects a first intermediate session management entity.

[0201] Specifically, the PDU session requirement information includes one or more of a PDU session type, an SSC mode, a local DNN, and a data transmission mode, and the data transmission mode is a Mutilhoming mode or a ULCL mode.

[0202] Among them, the session management entity determines the local DNN in the PDU session requirement information based on the information from the application function and the location information of the UE. The information from the application function includes the deployment information of the application, for example: which local DNs the application is deployed on, and this information uses the local DNN identifier. The session management entity selects a local DN close to the UE location based on the location of the UE and one or more local DNs deployed by the application, and uses the local DNN identifier corresponding to the selected local DN as the local DNN in the PDU session requirement information. It should be noted that other information in the PDU session requirement information, such as data transmission mode, PDU session type, etc., is still determined by the method in S304 and will not be repeated here.

[0203] Optionally, the session management entity needs to determine whether the first intermediate session management entity needs to be selected when selecting the first intermediate session management entity. The session management entity determines whether the first intermediate session management entity needs to be selected by:

[0204] When the session management entity determines, based on the PDU session requirement information, that the UPF connected to the local DN is not controlled by the session management entity, the session management entity selects (or obtains) a first intermediate session management entity based on the PDU session requirement information. Optionally, the session management entity obtains the first intermediate session management entity based on the UE's location information and the PDU session requirement information.

[0205] Optionally, the method for the session management entity to select the first intermediate session management entity may be:

[0206] a. The session management entity uses the intermediate session management entity that meets the PDU session requirement information as the first intermediate session management entity.

[0207] b. The session management entity selects a first intermediate session management entity based on the UE location information and the PDU session requirement information. The session management entity selects an intermediate session management entity that meets the PDU session requirement information and whose jurisdiction includes the serving base station indicated by the UE location information as the first intermediate session management entity.

[0208] c. When the PDU session requirement information includes the transmission mode and the local DNN, the session management entity will support the DN indicated by the local DNN and the intermediate session management entity that supports the transmission mode as the first intermediate session management entity.

[0209] d. When only the local DNN is included in the PDU session requirement information, the session management entity uses the intermediate session management entity that supports the DN indicated by the local DNN as the first intermediate session management entity.

[0210] e. When the PDU session requirement information only includes the transmission mode, the session management entity uses the intermediate session management entity that supports the transmission mode as the first intermediate session management entity.

[0211] Optionally, when the session management entity combines the UE location information and the PDU session requirement information, and the PDU session requirement information includes the local DNN and the transmission mode, the session management entity selects the first intermediate session management entity, for example: the session management entity uses the intermediate session management entity whose jurisdiction includes the service base station indicated by the UE location information, the DN indicated by the local DNN, and the transmission mode as the first intermediate session management entity. The method of selecting the first intermediate session management entity according to other combinations is similar to the above method, and the present invention will not be repeated.

[0212] S902: The session management entity sends a PDU session establishment request to the first intermediate session management entity, and the first intermediate session management entity receives the PDU session establishment request from the session management entity.

[0213] The PDU session establishment request carries the location information of the UE. The session management entity may send the location information of the UE to the first intermediate session management entity through the PDU session establishment request. The session management entity selects a user plane entity, such as a BP, a local anchor user plane entity, etc., according to the location information of the UE.

[0214] Optionally, the PDU session establishment request also carries a data transmission mode, and the data transmission mode is a Multihoming mode or a ULCL mode.

[0215] Optionally, when the data transmission mode is the Mutilhoming mode, the session management entity sends an uplink diversion strategy to the first intermediate session management entity, where the uplink diversion strategy is used to control the branch point BP anchored by the UE to divert traffic according to a source address of a data packet sent by the UE.

[0216] Optionally, when the data transmission mode is Mutilhoming mode, the session management entity sends the UE IP address (remote UE IP address) anchored at the anchor user plane entity to the first intermediate session management entity; the UE IP address (remote UE IP address) anchored at the anchor user plane entity is used to enable the first intermediate session management entity to generate an uplink diversion strategy, and the uplink diversion strategy is used by the Branching Point UPF to forward the received uplink data packets according to the source address.

[0217] Optionally, when the data transmission mode is the uplink classifier ULCL mode, the session management entity sends an uplink forwarding policy to the first intermediate session management entity, and the uplink forwarding policy is used to control the UE-anchored uplink classifier ULCL to forward according to one or more of the five-tuple and application identifier of the data packet sent by the UE.

[0218] Optionally, when the data transmission mode is the uplink classifier ULCL mode, the session management entity sends application information for accessing the local DN to the first intermediate session management entity, the application information is at least one of an application identifier and a five-tuple corresponding to the application, and the application information is used to instruct the first intermediate session management entity to determine an uplink forwarding strategy based on the application information, and the uplink forwarding strategy is used to control the uplink classifier ULCL anchored by the UE to forward according to one or more of the five-tuple and application identifier of the data packet sent by the UE.

[0219] Optionally, the session management entity sends routing information between the local anchor user plane entity and the local DN identified by the local DNN to the first intermediate session management entity, where the routing information is used to determine the forwarding path between the local anchor user plane entity and the local DN. The first intermediate session management entity determines the forwarding rules on the interface of the local anchor user plane entity facing the local DN based on the routing information.

[0220] Optionally, the session management entity also sends one or more of the PDU session type and the local DNN to the first intermediate session management entity, so that the first intermediate session management entity selects a local user plane entity according to the PDU session type and / or the local DNN.

[0221] S903: The first intermediate session management entity selects a local user plane entity.

[0222] Optionally, when the transmission mode is Mutilhoming mode, the first intermediate session management entity parses the UE location information in the PDU session establishment request. The first intermediate session management entity selects a local anchor user plane entity for the PDU session, and selects a BP for the PDU session; wherein the BP is used to divert data packets sent by the UE, the local anchor user plane entity is connected to the local data network DN indicated by the local DNN, and the BP is connected to the service base station indicated by the UE's location information.

[0223] Optionally, when the transmission mode is ULCL mode, the first intermediate session management entity selects a local anchor user plane entity for the PDU session, and selects an uplink classifier ULCL for the PDU session; wherein the ULCL is used to divert the application identifier and / or five-tuple of the data packet sent by the UE, the local anchor user plane entity is connected to the local DN indicated by the local DNN, and the ULCL is connected to the service base station indicated by the location information of the UE.

[0224] Optionally, when the jurisdiction of the local anchor user plane entity includes the serving base station of the UE, the local anchor user plane entity and the user plane entity BP / ULCL connected to the serving base station may be the same user plane entity.

[0225] The first intermediate session management entity selects a BP or a ULCL according to the location information of the UE:

[0226] The first intermediate session management entity selects a user plane entity connected to a serving base station indicated by the location of the UE as a BP or a ULCL.

[0227] Optionally, when the first intermediate session management entity receives a PDU session establishment request from the session management entity including one or more of a transmission mode, a local DNN, and a PDU session type, the first intermediate session management entity may further select a local session anchor user plane entity according to one or more of the transmission mode, the local DNN, and the PDU session type:

[0228] Optionally, the first intermediate session management entity selects a local session anchor user plane entity according to the data transmission mode, and the first intermediate session management entity selects a user plane entity that supports the data transmission mode indicated by the session management entity as the local session anchor user plane entity.

[0229] Optionally, the first intermediate session management entity selects a local session anchor user plane entity according to the local DNN, and the first intermediate session management entity selects a user plane entity that supports the local DNN indicated by the session management entity as the local session anchor user plane entity.

[0230] Optionally, the first intermediate session management entity selects a local session anchor user plane entity according to the type of the PDU session, and the first intermediate session management entity selects a user plane entity that supports the type of PDU session indicated by the session management entity as the local session anchor user plane entity.

[0231] Optionally, the first intermediate session management entity may also select a local session anchor user plane entity based on a combination of any two or three of the data transmission mode, local DNN, and PDU session type. For example, the first intermediate session management entity selects a local session anchor user plane entity based on the transmission mode and the local DNN. At this time, the first intermediate session management entity selects a user plane entity that supports the data transmission mode indicated by the session management entity and supports the local DNN indicated by the session management entity as the local session anchor user plane entity. The selection methods for other combinations can be deduced accordingly and will not be repeated here. Optionally, if the local session anchor user plane entity selected according to the above selection method supports connection to the service base station indicated by the location of the UE, the user plane entity can be selected as a combination of BP / ULCL and the local session anchor user plane entity.

[0232] S904: The first intermediate session management entity sends an N4 message to the selected BP or ULCL, and the BP / ULCL receives the message. This step is the same as S307 and will not be described in detail here.

[0233] S905: The first intermediate session management entity sends an N4 message to the selected local anchor user plane entity. This step is the same as S308 and will not be described in detail here.

[0234] S906: The first intermediate session management entity sends a response message to the session management entity, and the session management entity receives the response message from the first intermediate session management entity.

[0235] The response message may carry N9 downlink tunnel information of BP or ULCL. In addition, when the data transmission mode is Multihoming, the first intermediate session management entity may also send the local UE IP address to the session management entity.

[0236] S907: The session management entity sends an N4 message to the anchor user plane entity, and the anchor user plane entity receives the N4 message from the session management entity. This step is the same as S310.

[0237] S908: Allocate radio resources for the PDU session. This step is the same as S311.

[0238] S909: The session management entity sends a PDU session update request to the first intermediate session management entity, and the first intermediate session management entity receives the PDU session update request from the session management entity. This step is the same as S312.

[0239] S910: The first intermediate session management entity sends a PDU session update request to the BP / UCLC, and the BP / ULCL receives the PDU session update request from the first intermediate session management entity. This step is the same as S313.

[0240] S911, the first intermediate session management entity sends a response message to the session management entity, and the session management entity receives the response message from the first intermediate session management entity. The response message indicates that the update of the PDU session is completed. This step is the same as S314.

[0241] S912: The first intermediate session management entity sends a routing advertisement to the user equipment through the local anchor user plane entity.

[0242] Among them, the transmission mode in this step is the Mutilhoming mode, and the routing announcement carries the uplink routing policy and the local UE IP address assigned by the first intermediate session management entity. The uplink routing policy is used to control the UE to select the remote UE IP address assigned by the session management entity or the local UE IP address assigned by the first intermediate session management entity as the source address when sending a data packet. Optionally, the session management entity can also send a routing announcement to the user equipment as needed, and the routing announcement is used to indicate the UE to select the remote UE IP address or the rule of the remote UE IP address.

[0243] See also Fig.10 , which is a flow chart of a session management method provided in an embodiment of the present invention. In this embodiment, it is an explanation of the switching process of architecture 1a. Before the switching, the source access network of the UE provides services for the PDU session for the serving base station (not shown in the figure), the source intermediate session management entity (the first intermediate session management entity), the source user plane entity and the anchor user plane entity.

[0244] When the switching occurs, the method includes but is not limited to the following steps:

[0245] S1001: The target access network sends a path switching request to the session management entity through the access management entity, and the session management entity receives the path switching request from the target access network. The description of S401 is the same and will not be repeated here.

[0246] S1002: The session management entity selects a target intermediate session management entity.

[0247] Among them, the session management entity determines that the UE can access the application more conveniently through the target local DN (such as closer or faster access to the application) based on the UE's location information. The session management entity uses the target local DNN corresponding to the target local DN as the local DNN in the PDU session demand information. The session management entity selects the target intermediate session management entity. The specific selection process can be referred to Fig. 9 The description of S901 is not repeated here.

[0248] S1003: The session management entity sends a PDU session establishment request to the target intermediate session management entity, and the target intermediate session management entity receives the request from the session management entity. This is the same as the description of S902 and will not be repeated here.

[0249] S1004: The target intermediate session management entity selects a target user plane entity. This is the same as the description of S903 and will not be repeated here.

[0250] It should be noted that the target intermediate session management entity sends an N4 message to the selected target user plane entity, the target user plane entity receives the N4 message from the target intermediate session management entity, the target user plane entity creates an N9 tunnel with the anchor user plane entity, and creates an N3 tunnel with the target access network. The target intermediate session management entity sends a response message to the session management entity, the response message carries the identification information of the N3 tunnel and the identification information of the N9 tunnel created above, the session management entity receives the identification information of the N3 tunnel and the identification information of the N9 tunnel sent from the intermediate session management entity, and updates the identification information of the N9 tunnel of the anchor user plane entity. The session management entity sends a switching response message to the access management entity, the access management entity receives the switching response message from the session management entity, and learns that the tunnel update process is completed.

[0251] In implementing the embodiments of the present invention, when the location of the UE is updated, the session management entity selects the intermediate session management entity and the user plane entity close to the UE to provide services for the UE, thereby reducing the delay during data transmission. At the same time, the session management entity and the intermediate session management entity are only responsible for managing the user plane entities within their jurisdiction, and do not need to manage all user plane entities in the entire PDU session, thereby reducing the number of messages between the user plane entities and alleviating the workload.

[0252] It should be noted that, in a possible implementation manner, Figure 7 The device 7 shown can realize Figure 3-Figure 7 In the access management entity or session management entity of the illustrated embodiment, the device 7 includes: a selection unit 701 and a transceiver unit 702 .

[0253] The selecting unit 701 is configured to select a first intermediate session management entity for a PDU session according to location information of a user equipment UE and PDU session requirement information.

[0254] The transceiver unit 702 is configured to send the location information of the UE and the PDU session requirement information to the first intermediate session management entity; wherein the location information of the UE and the PDU session requirement information are used to select a user plane entity. Optionally, the PDU session requirement information includes: one or more of a session and service continuity SSC mode and a PDU session type.

[0255] Optionally, the selection unit 701 is used to select a first intermediate session management entity for the PDU session based on the location information of the UE and the protocol data unit PDU session requirement information, including: selecting an intermediate session management entity that simultaneously meets the PDU session requirement information and whose jurisdiction includes the service base station indicated by the location information of the UE as the first intermediate session management entity.

[0256] Optionally, the device 7 further includes a judgment unit;

[0257] A judging unit, configured to, if the network device judges that there is no intermediate session management entity that satisfies the PDU session requirement and has a jurisdiction that includes a serving base station indicated by the location information of the UE;

[0258] The selection unit 701 is further configured to select a second intermediate session management entity that meets the PDU session requirement information, and select a third intermediate session management entity whose jurisdiction includes a serving base station indicated by the location information of the UE.

[0259] Optionally, the PDU session requirement information includes a data transmission mode and a local data network name DNN.

[0260] Optionally, the selecting unit 701, configured to select a first intermediate session management entity for a PDU session according to the location information of the UE and the protocol data unit PDU session requirement information, includes:

[0261] Select as the first intermediate session management entity a service base station whose jurisdiction includes the location information indication of the UE and the local data network DN indicated by the local DNN included in the PDU session requirement information, and an intermediate session management entity that supports the data transmission mode in the PDU session requirement information.

[0262] Optionally, the device 7 further includes: a judgment unit;

[0263] The judging unit is further configured to: if the network device judges that there is no serving base station whose jurisdiction includes the location information indication of the UE and the local DN indicated by the local DNN, and an intermediate session management entity supporting the data transmission mode included in the PDU session requirement information;

[0264] The selection unit 701 is also used to select a second intermediate session management entity whose jurisdiction includes a serving base station indicated by the location information of the UE, and select a third intermediate session management entity whose jurisdiction includes a local DN indicated by a local DNN included in the PDU session requirement information and supports the data transmission mode included in the PDU session requirement information.

[0265] Optionally, the data transmission mode is a multi-homing mode, and the transceiver unit 702 is further configured to:

[0266] Sending an uplink offload strategy and an uplink routing strategy to the first intermediate session management entity; wherein the uplink offload strategy is used to control the branch point BP anchored by the UE to offload according to the source address of the data packet sent by the UE, and the uplink routing strategy is used to control the UE to use the IP address anchored at the anchor user plane entity or the local IP address anchored at the local anchor user plane entity as the source address of the data packet; or

[0267] The IP address anchored at the anchor user plane entity and the uplink routing policy corresponding to the IP address anchored at the anchor user plane entity are sent to the first intermediate session management entity; the IP address anchored at the anchor user plane entity is used to enable the first intermediate session management entity to generate an uplink diversion policy, and the uplink routing policy corresponding to the IP address anchored at the anchor user plane entity is used to enable the first intermediate session management entity to generate an uplink routing policy; the uplink diversion policy is used to control the BP to divert according to the source address of the data packet sent by the UE, and the uplink routing policy is used to instruct the UE to use the IP address anchored at the anchor user plane entity or the local IP address anchored at the local anchor user plane entity as the source address to send data.

[0268] Optionally, the data transmission mode is an uplink classifier ULCL mode, and the transceiver unit 702 is further used to:

[0269] An uplink forwarding policy is sent to the first intermediate session management entity; wherein the uplink forwarding policy is used to control the uplink classifier ULCL anchored by the UE to forward according to one or more of the quintuple and application identifier of the data packet sent by the UE.

[0270] Optionally, the selection unit 701 is further configured to:

[0271] When the UE is switched from the current serving base station to the target base station, and the target base station is not located within the jurisdiction of the first intermediate session management entity, a target session management entity is selected.

[0272] Optionally, the selecting unit 701 is configured to select a target session management entity including:

[0273] If it is determined that there is an intermediate session management entity that meets the PDU session requirement information and whose jurisdiction includes the target base station to which the UE is switched; select an intermediate session management entity that meets both the jurisdiction including the target base station to which the UE is switched and the PDU session requirement information as the target intermediate session management entity; or

[0274] If it is determined that there is no intermediate session management entity that meets the PDU session requirement information and whose jurisdiction includes the target base station to which the UE switches; the network device selects a second intermediate session management entity that meets the PDU session requirement information and a third intermediate session management entity whose jurisdiction includes the target base station to which the UE switches as the target intermediate session management entities.

[0275] Optionally, the device 7 is a session management entity, and the device 7 further includes a determining unit,

[0276] A determination unit, configured to determine the PDU session requirement information according to the PDU session contract information; or determine the PDU session requirement information according to one or more of the PDU session policy information and the PDU session expectation information, and the PDU session contract information;

[0277] The selection unit 701 is further configured to select an anchor user plane entity within the jurisdiction of the session management entity according to the PDU session requirement information;

[0278] The determining unit is further configured to determine, according to the location information of the UE, that the serving base station indicated by the location information of the UE is not connected to the anchor user plane entity.

[0279] Optionally, the device 7 is a session management entity, and the session management device 7 further includes a determination unit.

[0280] The determining unit is used to determine the PDU session requirement information according to the PDU session contract information; or determine the PDU session requirement information according to one or more of the PDU session policy information and the PDU session expectation information, and the PDU session contract information; the PDU session requirement information includes the local DNN;

[0281] The judging unit is further configured to judge that the local DN indicated by the local DNN included in the PDU session requirement information is not within the jurisdiction of the session management entity.

[0282] Optionally, device 7 is an access management entity.

[0283] The selection unit 701 is further configured to select a session management entity. The judgment unit is further configured to judge that the serving base station indicated by the location information of the UE is not located within the jurisdiction of the session management entity. The selection unit 701 is further configured to select a fourth intermediate session management entity. The transceiver unit 702 is further configured to receive the PDU session requirement and reselection indication message from the session management entity, wherein the reselection indication message is used to instruct the access management entity to select the first intermediate session management entity.

[0284] Optionally, device 7 is an access management entity.

[0285] The selection unit 701 is further configured to select a session management entity.

[0286] The judging unit is further configured to judge that the serving base station indicated by the location information of the UE is not located within the jurisdiction of the session management entity. The selecting unit 701 is further configured to select a fourth intermediate session management entity. The transceiver unit 702 is further configured to receive the PDU session requirement information from the session management entity. The judging unit is further configured to judge that the fourth intermediate session management entity does not meet the PDU session requirement information.

[0287] Optionally, device 7 is an access management entity.

[0288] The transceiver unit 702 is also used to receive new PDU session requirement information and a reselection indication message from the session management entity when the requirement for the PDU session changes, and the reselection indication message is used to instruct the session management device 7 to select the first intermediate session management entity.

[0289] Optionally, the network device is an access management entity. The transceiver unit is further configured to, when the demand for the PDU session changes, cause the network device to receive new PDU session demand information from the session management entity;

[0290] The judging unit is further configured to judge that the first intermediate session management entity does not meet the new PDU session requirement information. The selecting unit 701 is further configured to select a target intermediate session management entity according to the location information of the UE and the new PDU session requirement information.

[0291] Optionally, the device 7 is a session management entity, and the device 7 also includes a determination unit. The determination unit is used to determine the PDU session requirement information according to the PDU session contract information; or determine the PDU session requirement information according to one or more of the PDU session policy information and the PDU session expectation information, as well as the PDU session contract information. The judgment unit is also used to judge that the fourth intermediate session management entity selected by the access management entity does not meet the PDU session requirement. The transceiver unit 702 is also used to send the identification information of the first intermediate session management entity to the access management entity.

[0292] It should be noted that, in another possible implementation, Figure 7 The device 7 shown can realize Fig. 9 and Fig.10 In the session management entity of the illustrated embodiment, the device 7 includes: a selection unit 701 and a transceiver unit 702 .

[0293] The selection unit 701 is configured to select a first intermediate session management entity for a protocol data unit PDU session according to a protocol local network data name DNN.

[0294] The transceiver unit 702 is configured to send location information of a user equipment UE to the first intermediate session management entity; wherein the location information of the UE is used to select a user plane entity.

[0295] Optionally, the selecting unit 701 executing the selecting of the first intermediate session management entity for the PDU session according to the local DNN includes:

[0296] A first intermediate session management entity is selected according to the location information of the local DNN and the UE; wherein the first intermediate session management entity is selected that supports the local data network DN indicated by the local DNN and the service base station whose jurisdiction includes the location information indication of the UE.

[0297] Optionally, the selecting unit 701 executing the selecting of the first intermediate session management entity for the PDU session according to the local DNN includes:

[0298] An intermediate session management entity that supports the local DN indicated by the local DNN is selected as the first intermediate session management entity.

[0299] Optionally, the network device is a session management entity, and the selecting unit 701 is further configured to:

[0300] The local DNN is determined based on information from the application function.

[0301] Optionally, the transceiver unit 702 is further configured to:

[0302] The location information of the UE is sent to a first intermediate session management entity; wherein the location information of the UE is used to instruct the first intermediate session management entity to select a user plane entity supporting the UE location, and the user plane entity supporting the UE location is an access network interface connected to the UE.

[0303] Optionally, the transceiver unit 702 is further configured to:

[0304] The local DNN is sent to the first intermediate session management entity; wherein the local DNN is used to instruct the first intermediate session management entity to select a local anchor user plane entity.

[0305] Optionally, the user plane entity selected by the first intermediate session management entity supports both the local DNN and the UE location information; or

[0306] In the absence of a user plane entity that supports both the local DNN and the UE location information, the first intermediate session management entity selects a user plane entity that supports the local DNN as a local anchor user plane entity based on the local DNN, and selects a user plane entity that supports the UE location information based on the UE location information for interfacing with the access network to which the UE is connected, wherein the local anchor user plane entity is used to interface with the local DN.

[0307] Optionally, the transceiver unit 702 is further configured to:

[0308] Sending a data transmission mode to the first intermediate session management entity; wherein the data transmission mode is used to instruct the first intermediate session management entity to determine an uplink diversion rule.

[0309] Optionally, the transceiver unit 702 is further configured to:

[0310] If the data transmission mode is multihoming, the remote UE IP address is sent to the first intermediate session management entity; wherein the remote UE IP is used to instruct the first intermediate session management entity to determine an uplink diversion rule.

[0311] Optionally, the transceiver unit 702 is further configured to:

[0312] If the data transmission mode is the uplink classifier ULCL, the application information is sent to the first intermediate session management entity to determine the uplink diversion rule according to the application information; wherein the application information is at least one of the application identifier or the five-tuple corresponding to the application.

[0313] Optionally, the transceiver unit 702 is further configured to:

[0314] An uplink diversion rule or an uplink forwarding rule is sent to the first intermediate session management entity; wherein the uplink diversion rule or the uplink forwarding rule is used to instruct the first intermediate session management entity to configure the user plane entity, thereby realizing uplink data diversion.

[0315] Optionally, the transceiver unit 702 is further configured to:

[0316] The routing information between the local anchor point and the local data network DN identified by the local DNN is sent to the first intermediate session management entity, where the routing information is used to determine a forwarding path between the user plane entity and the local DN.

[0317] The device 7 can be an access management entity or a session management entity. The device 7 can also be a field-programmable gate array (FPGA), an application specific integrated circuit (ASIC), a system on chip (SoC), a central processor unit (CPU), a network processor (NP), a digital signal processor (DSP), a microcontroller unit (MCU) for implementing relevant functions. A programmable logic device (PLD) or other integrated chips can also be used.

[0318] like Figure 8 As shown, the embodiment of the present invention further provides a network device 8.

[0319] The network device may be an access management entity or a session management entity, including:

[0320] The memory 802 is used to store programs and data; the memory may be a random access memory (RAM) or a read-only memory (ROM) or a flash memory, and the memory 802 may be located in a separate communication device or inside the processor 801.

[0321] The processor 801 is used to execute the program stored in the memory. When the program is executed, the processor 801 is used to select a first intermediate session management entity for a PDU session according to location information of a user equipment UE and protocol data unit PDU session requirement information.

[0322] The transceiver 803 may be a separate chip, or a transceiver circuit in the processor 801, or an input / output interface. The transceiver 803 is configured to send the location information of the UE and the PDU session requirement information to the first intermediate session management entity; wherein the location information of the UE and the PDU session requirement information are used to select a user plane entity.

[0323] It should be noted that the network device and Figure 7 A session management device, and Figures 3 to 6 as well as Fig. 9 and Fig.10The method flow is based on the same concept, and the technical effect it brings is also the same. The specific process can be referred to Figure 7 The session management device and Figures 3 to 6 as well as Fig. 9 and Fig.10 The description of the method flow will not be repeated here.

[0324] The transceiver 803 , the memory 802 , and the processor 801 may be optionally connected via a bus.

[0325] When the network device 8 is a chip, it can be a field-programmable gate array (FPGA) for implementing relevant functions, an application specific integrated circuit (ASIC), a system on chip (SoC), a central processor unit (CPU), a network processor (NP), a digital signal processor (DSP), a microcontroller unit (MCU), and a programmable logic device (PLD) or other integrated chips.

[0326] These chips can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using a software program, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium may be any available medium that a computer can access or may contain one or more servers, data centers and other data storage devices that can be integrated with the medium. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)).

[0327] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0328] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0329] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0330] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0331] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0332] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions can be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state hard disk Solid State Disk (SSD)), etc.

[0333] Those skilled in the art can understand that to implement all or part of the processes in the above-mentioned embodiments, the processes can be completed by computer programs to instruct related hardware, and the programs can be stored in computer-readable storage media. When the programs are executed, they can include the processes of the above-mentioned method embodiments. The aforementioned storage media include: ROM or random access memory RAM, magnetic disk or optical disk and other media that can store program codes.

Claims

1. A session management method, characterized in that: include: The access management entity selects a first intermediate session management entity for the PDU session according to location information of the user equipment UE and protocol data unit PDU session requirement information, wherein the PDU session requirement information includes information for indicating the local data network DN; The access management entity sends the PDU session requirement information to the first intermediate session management entity; wherein the PDU session requirement information is used to select a user plane entity.

2. The method according to claim 1, characterized in that The method further comprises: The access management entity receives a reselection indication from a session management entity, where the reselection indication is used to instruct the access management entity to select the first intermediate session management entity.

3. The method according to claim 1 or 2, characterized in that The method further comprises: The access management entity receives the PDU session requirement information from a session management entity.

4. The method according to any one of claims 1-2, characterized in that: The user plane entity comprises a local anchor user plane entity, and the local anchor user plane entity is connected to the local DN.

5. The method according to claim 1 or 2, characterized in that: The method further includes: the access management entity receiving a PDU session establishment request from the UE, where the PDU session establishment request is used to request establishment of a PDU session.

6. The method according to claim 1 or 2, characterized in that: The PDU session requirement information is used to indicate the relevant parameter requirements of the PDU session that the network side can accept.

7. The method according to any one of claims 1-2, characterized in that: Also includes: The access management entity sends the location information of the UE to the first intermediate session management entity.

8. The method according to claim 7, characterized in that The location information of the UE is also used to select the user plane entity.

9. The method according to any one of claims 1-2, characterized in that: The information used to indicate the local data network DN includes: a local data network name DNN.

10. A communication system, characterized in that: comprising an access management entity and a first intermediate session management entity, wherein: The access management entity is used to select a first intermediate session management entity for a PDU session according to location information of a user equipment UE and protocol data unit PDU session requirement information, wherein the PDU session requirement information includes information for indicating a local data network DN; The first intermediate session management entity is used to receive the PDU session requirement information from the access management entity, and select a user plane entity according to the PDU session requirement information.

11. The system of claim 10, wherein , The selecting a user plane entity according to the PDU session requirement information includes: selecting a local anchor user plane entity according to the PDU session requirement information, and selecting an uplink classifier or a branch point.

12. The system according to claim 10, characterized in that Also includes a session management entity.

13. The system of claim 12, wherein: If the data transmission mode is Multihoming, The session management entity is further used to send a remote UE IP address to the first intermediate session management entity; wherein the remote UE IP is used to instruct the first intermediate session management entity to determine an uplink diversion rule; The first intermediate session management entity is further used to receive the UE IP address.

14. The system of claim 12, wherein: If the data transmission mode is uplink classifier ULCL, The session management entity is further used to send application information to the first intermediate session management entity, wherein the application information is used to instruct the first intermediate session management entity to determine an uplink diversion rule; the application information is at least one of an application identifier or a five-tuple corresponding to an application; The first intermediate session management entity is further used to receive the application information.

15. The system according to any one of claims 12 to 14, characterized in that: The session management entity is further used to send an uplink diversion rule or an uplink forwarding rule to the first intermediate session management entity; wherein the uplink diversion rule or the uplink forwarding rule is used to instruct the first intermediate session management entity to configure the user plane entity, thereby realizing uplink data diversion; The first intermediate session management entity is further used to receive the uplink diversion rule or the uplink forwarding rule.

16. The system according to any one of claims 12 to 14, characterized in that: The session management entity is also used to send routing information between the local anchor point and the local data network DN identified by the local DNN to the first intermediate session management entity, and the routing information is used to determine the forwarding path between the user plane entity and the local data network DN; the first intermediate session management entity is also used to receive the routing information.

17. The system of claim 12, wherein: The session management entity is further used to send a reselection indication to the access management entity, where the reselection indication is used to instruct the access management entity to select the first intermediate session management entity; The access management entity is further configured to receive the reselection indication from the session management entity.

18. The system of claim 13, wherein: Also includes: The session management entity is further used to determine the PDU session requirement information according to the PDU session policy information.

19. The system according to any one of claims 10 to 14, characterized in that: The user plane entity comprises a local anchor user plane entity, and the local anchor user plane entity is connected to the local DN.

20. The system according to any one of claims 10 to 14, characterized in that: The access management entity is further used to receive a PDU session establishment request from the UE, where the PDU session establishment request is used to request to establish a PDU session.

21. The system according to any one of claims 10 to 14, characterized in that: The PDU session requirement information is used to indicate the relevant parameter requirements of the PDU session that the network side can accept.

22. The system according to any one of claims 10 to 14, characterized in that: The access management entity is further used to send the location information of the UE to the first intermediate session management entity.

23. The system of claim 22, wherein: The selecting a user plane entity according to the PDU session requirement information includes: selecting the user plane entity according to the location information of the UE and the PDU session requirement information.

24. The system according to any one of claims 10 to 14, characterized in that: The information used to indicate the local data network DN includes: a local data network name DNN.

25. A session management method, characterized in that: include: The access management entity selects a first intermediate session management entity for the PDU session according to location information of the user equipment UE and protocol data unit PDU session requirement information, wherein the PDU session requirement information includes information for indicating the local data network DN; The access management entity sends the PDU session requirement information to the first intermediate session management entity; wherein the PDU session requirement information is used to select a user plane entity; The first intermediate session management entity receives the PDU session requirement information, and selects a user plane entity according to the PDU session requirement information.

26. The method of claim 25, wherein , The selecting a user plane entity according to the PDU session requirement information includes: selecting a local anchor user plane entity according to the PDU session requirement information, and selecting an uplink classifier or a branch point.

27. The method of claim 26, wherein: The method further comprises: The access management entity receives a reselection indication from a session management entity, where the reselection indication is used to instruct the access management entity to select the first intermediate session management entity.

28. The method according to claim 26 or 27, characterized in that The method further comprises: The access management entity receives the PDU session requirement information from a session management entity.

29. The method according to claim 26 or 27, characterized in that The user plane entity comprises a local anchor user plane entity, and the local anchor user plane entity is connected to the local DN.

30. The method according to claim 26 or 27, characterized in that The method further includes: the access management entity receiving a PDU session establishment request from the UE, where the PDU session establishment request is used to request establishment of a PDU session.

31. The method according to claim 26 or 27, characterized in that The PDU session requirement information is used to indicate the relevant parameter requirements of the PDU session that the network side can accept.

32. The method according to any one of claims 26-27, characterized in that: The access management entity is further used to send the location information of the UE to the first intermediate session management entity.

33. The method of claim 32, wherein: The selecting a user plane entity according to the PDU session requirement information includes: selecting the user plane entity according to the location information of the UE and the PDU session requirement information.

34. The method according to any one of claims 26-27, characterized in that: The information used to indicate the local data network DN includes: a local data network name DNN.

35. An access management entity, characterized in that: include: A unit for executing the method according to any one of claims 1 to 9.

36. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, which, when executed on a computer, enable the computer to execute the method according to any one of claims 1 to 9.

37. A computer program product, characterized in that The computer program product stores instructions, and when the computer program product is run on a computer, the computer can execute the method according to any one of claims 1 to 9.

38. An access management entity, characterized in that: include: transceivers, memory, and processors; Wherein, the memory is used to store programs and data; The processor is configured to execute the program stored in the memory, and when the program is executed, the processor is configured to select a first intermediate session management entity for a PDU session according to location information of a user equipment UE and protocol data unit PDU session requirement information, wherein the PDU session requirement information includes information for indicating a local data network DN; The transceiver is used to send the PDU session requirement information to the first intermediate session management entity; wherein the PDU session requirement information is used to select a user plane entity.

39. The access management entity according to claim 38, characterized in that: The transceiver is further configured to receive a reselection indication from a session management entity, where the reselection indication is used to instruct the access management entity to select the first intermediate session management entity.

40. The access management entity according to claim 38 or 39, characterized in that: The transceiver is further configured to receive the PDU session requirement information from a session management entity.

41. The access management entity according to claim 38 or 39, characterized in that: The user plane entity comprises a local anchor user plane entity, and the local anchor user plane entity is connected to the local DN.

42. The access management entity according to claim 38 or 39, characterized in that: The transceiver is further used to receive a PDU session establishment request from the UE, where the PDU session establishment request is used to request to establish a PDU session.

43. The access management entity according to claim 38 or 39, characterized in that: The PDU session requirement information is used to indicate the relevant parameter requirements of the PDU session that the network side can accept.

44. The access management entity according to claim 38 or 39, characterized in that: The access management entity is further used to send the location information of the UE to the first intermediate session management entity.

45. The access management entity according to claim 44, characterized in that The location information of the UE is also used to select the user plane entity.

46. ​​The access management entity according to claim 38 or 39, characterized in that: The information used to indicate the local data network DN includes: a local data network name DNN.

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