CN111371577B

CN111371577B - Communication method and communication device

Info

Publication number: CN111371577B
Application number: CN201811597814.2A
Authority: CN
Inventors: 杨文进
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2018-12-26
Filing date: 2018-12-26
Publication date: 2022-06-28
Anticipated expiration: 2038-12-26
Also published as: CN111371577A

Abstract

The application provides a communication method and a communication device, comprising the following steps: the service gateway determines the identifier of a first session, wherein the first session is a session of a first network element in a network element set which is migrated out of the first session and has a backup relationship with each other; the serving gateway determines first information according to the identifier of the first session, where the first information is used to indicate a second network element in the network element set to serve the first session, and the identifier of the first session can uniquely indicate the first session in the first network element and the second network element; and the service gateway sends the first information to the second network element. According to the communication method, when the fusion node cannot continuously provide the service for the session, other fusion nodes can continuously provide the service for the session.

Description

Communication method and communication device

Technical Field

The present embodiment relates to the field of communications, and in particular, to a communication method and a communication apparatus.

Background

With the development of the fifth generation mobile communication system (5G), diversified service demands bring new technical challenges to the existing network, and different services have different demands for network functions, for example, enhanced mobile broadband (eMBB) service requires scheduling with high throughput, and ultra-low latency (URLLC) service requires ultra-low latency and ultra-high reliability guarantee. Therefore, in order to meet such a high reliability requirement, a 5G core network needs to have full redundancy and scalability, and the normal operation of a service is not affected by addition, deletion, or failure of a Network Function (NF) node.

An interworking architecture between a 5G system (5th generation system, 5GS) and an Evolved Packet Core (EPC) has been defined in the 5G standard, where 3 convergence nodes of Session Management Function (SMF) + PDN gateway control plane function (PGW-C), Policy Control Function (PCF) + Policy and Charging Rules Function (PCRF), and user plane function (user plane function, UPF) + PDN gateway user plane function (PDN gateway user plane function, PGW-U) can be used for interworking between 5GS and EPC. For example, the SMF + PGW-C fusion node has the functions of 5GS SMF and EPC PGW-C, and for a 5G network, the fusion node can realize the SMF function and can provide a service interface to the outside; for EPC networks, the fusion node can implement PGW-C functions, and can interact with the SGW through S5/S8-C interfaces.

However, the reliability scheme in the current 5G standard is designed based on a 5th generation core (5 GC) service architecture, and does not consider the characteristics of the evolved EPC network in the fourth generation mobile communication system (4G), and is not applicable to the above-mentioned fusion node.

Disclosure of Invention

The application provides a communication method and a communication device, which can enable other fusion nodes to continue to provide services for a session when the fusion nodes cannot continue to provide the services for the session.

In a first aspect, a communication method is provided, including: the service gateway determines the identifier of a first session, wherein the first session is a session of a first network element in a network element set which is migrated out of the first session and has a backup relationship with each other; the serving gateway determines first information according to the identifier of the first session, where the first information is used to indicate a second network element in the network element set to serve the first session, and the identifier of the first session can uniquely indicate the first session in the first network element and the second network element; and the service gateway sends the first information to the second network element.

According to the communication method provided in the embodiment of the present application, the serving gateway determines first information according to the identifier of the first session, where the first information is used to indicate a second network element in the network element set to serve the first session, and sends the first information to the second network element, so that when the first network element cannot continue to serve the first session, the second network element can continue to serve the first session.

In some possible implementations, the identifier of the first session includes a session group identifier and an intra-session group identifier, where the session group identifier is used to indicate a session group in which the first session is located, and the intra-session group identifier is used to indicate the first session in the session group.

In some possible implementations, the communication method further includes: and the serving gateway sends second information to a mobility management entity, where the second information is used to indicate that the first session is migrated out of the first network element.

In some possible implementations, the communication method further includes: and the serving gateway receives third information sent by the mobility management entity, where the third information is used to trigger the serving gateway to send the first information to the second network element.

In some possible implementations, the third information includes identification information of the second network element.

In some possible implementations, the determining, by the serving gateway, first information according to the identifier of the first session includes: in response to the third information, the serving gateway determines the first information according to the identity of the first session.

In some possible implementations, the first information includes identification information of the second network element.

In a second aspect, a communication method is provided, including: a mobility management entity determines an identifier of a first session, wherein the first session is a session of a first network element in a network element set which is migrated out of a backup relationship with each other; the mobility management entity determines third information according to the identifier of the first session, where the third information is used to indicate that the first session is migrated to the second network element, and the identifier of the first session can uniquely indicate the first session in the first network element and the second network element; and the mobility management entity sends the third information to a service gateway.

According to the communication method provided in the embodiment of the present application, the mobility management entity determines third information according to the identifier of the first session, where the third information is used to indicate that the first session is migrated to the second network element, and sends the first information to the serving gateway, so as to trigger the serving gateway to send the first information to the second network element, and when the first network element cannot continue to provide services for the first session, the second network element continues to provide services for the first session.

In some possible implementations, the communication method further includes: and the mobility management entity receives second information sent by the serving gateway, where the second information is used to indicate that the first session is migrated out of the first network element.

In some possible implementations, the determining, by the mobility management entity, third information according to the identifier of the first session includes: and responding to the second information, and the mobility management entity determines third information according to the identification of the first session.

In a third aspect, a communication method is provided, including: the method comprises the steps that a second network element determines that a first session is migrated from a first network element to the second network element, and the first network element and the second network element belong to a network element set which are in a backup relationship with each other; and the second network element allocates a session identifier for the first session, and the session identifier can uniquely indicate the first session in the second network element.

According to the communication method provided in the embodiment of the present application, the second network element determines that the first session is migrated from the first network element to the second network element, and at this time, the second network element allocates a session identifier to the first session, and the session identifier can uniquely indicate the first session in the second network element, so that when the first network element cannot continue to provide a service for the first session, the second network element may continue to provide a service for the first session.

In some possible implementation manners, the identifier of the first session includes a session group identifier and an intra-session group identifier, where the session group identifier is used to indicate a session group in which the first session is located, and the intra-session group identifier is used to indicate the first session in the session group.

In some possible implementations, the communication method further includes: and the second network element sends fourth information to a service gateway, wherein the fourth information is used for indicating that the first session is migrated to the second network element.

In some possible implementations, the fourth information is determined by the second network element according to session context information stored by an unstructured data storage function network element.

In a fourth aspect, a communication apparatus is provided, including: a processing unit, configured to determine an identifier of a first session, where the first session is a session of a first network element in a network element set migrated out of a backup relationship with each other; the processing unit is further configured to determine first information according to an identifier of the first session, where the first information is used to indicate a second network element in the network element set to serve the first session, and the identifier of the first session is capable of uniquely indicating the first session in the first network element and the second network element; a sending unit, configured to send the first information to the second network element.

According to the communication apparatus provided in the embodiment of the present application, the communication apparatus determines, according to the identifier of the first session, first information, where the first information is used to indicate a second network element in the network element set to serve the first session, and sends the first information to the second network element, so that when the first network element cannot continue to serve the first session, the second network element can continue to serve the first session.

In some possible implementations, the sending unit is further configured to send, to a mobility management entity, second information, where the second information is used to indicate that the first session is migrated out of the first network element.

In some possible implementation manners, the communication apparatus further includes a receiving unit, configured to receive third information sent by the mobility management entity, where the third information is used to trigger the serving gateway to send the first information to the second network element.

In some possible implementations, the processing unit is specifically configured to: in response to the third information, determining the first information according to the identity of the first session.

The respective modules comprised by the apparatus in the fourth aspect may be implemented by software and/or hardware.

For example, the respective modules included in the apparatus in the fourth aspect may be implemented by a processor, that is, the apparatus in the fourth aspect may include a processor for executing program instructions to implement the respective functions that can be implemented by the respective modules included in the apparatus.

Optionally, the apparatus in the fourth aspect may further include a memory for storing program instructions executed by the processor, and even for storing various data.

Optionally, the apparatus in the fourth aspect may be a chip that can be integrated in a smart device, in which case, the apparatus may further include a communication interface.

In a fifth aspect, a communication apparatus is provided, including: a processing unit, configured to determine an identifier of a first session, where the first session is a session migrated out of a first network element in a network element set in a backup relationship with each other; the processing unit is further configured to determine third information according to the identifier of the first session, where the third information is used to indicate that the first session is migrated to the second network element, and the identifier of the first session can uniquely indicate the first session in the first network element and the second network element; and the sending unit is used for sending the third information to the service gateway.

According to the communication apparatus provided in the embodiment of the present application, the communication apparatus determines third information according to the identifier of the first session, where the third information is used to indicate that the first session is migrated to the second network element, and sends the first information to the serving gateway, so as to trigger the serving gateway to send the first information to the second network element, and when the first network element cannot continue to provide services for the first session, the second network element can continue to provide services for the first session.

In some possible implementations, the communication apparatus further includes a receiving unit, configured to receive second information sent by the serving gateway, where the second information is used to indicate that the first session is migrated out of the first network element.

In some possible implementations, the processing unit is specifically configured to: third information is determined from the identity of the first session in response to the second information.

The respective modules included in the apparatus of the fifth aspect may be implemented by software and/or hardware.

For example, the respective modules included in the apparatus in the fifth aspect may be implemented by a processor, that is, the apparatus in the fifth aspect may include a processor for executing program instructions to implement the respective functions that can be implemented by the respective modules included in the apparatus.

Optionally, the apparatus in the fifth aspect may further comprise a memory for storing program instructions executed by the processor, and even for storing various data.

Optionally, the apparatus in the fifth aspect may be a chip capable of being integrated in a smart device, in which case, the apparatus may further include a communication interface.

In a sixth aspect, a communication apparatus is provided, including: a processing unit, configured to determine that a first session is migrated from a first network element to a second network element, where the first network element and the second network element belong to a network element set in a backup relationship with each other; the processing unit is further configured to allocate a session identifier to the first session, where the session identifier is capable of uniquely indicating the first session in the second network element.

According to the communication method provided by the embodiment of the present application, the communication apparatus determines that the first session is migrated from the first network element to the communication apparatus, at this time, the communication apparatus assigns a session identifier to the first session, and the session identifier can uniquely indicate the first session in the communication apparatus, so that when the first network element cannot continue to provide services for the first session, the communication apparatus can continue to provide services for the first session.

In some possible implementations, the communication apparatus further includes a sending unit, configured to send fourth information to a serving gateway, where the fourth information is used to indicate that the first session is migrated to the second network element.

The apparatus in the sixth aspect may include various modules that are implemented by software and/or hardware.

For example, the respective modules included in the apparatus in the sixth aspect may be implemented by a processor, that is, the apparatus in the sixth aspect may include a processor for executing program instructions to implement the respective functions that can be implemented by the respective modules included in the apparatus.

Optionally, the apparatus in the sixth aspect may further comprise a memory for storing program instructions executed by the processor, and even for storing various data.

Optionally, the apparatus in the sixth aspect may be a chip capable of being integrated in a smart device, in which case, the apparatus may further include a communication interface.

In a seventh aspect, the present application provides a computer-readable storage medium. The computer readable storage medium has stored therein program code for execution by the communication device. The program code comprises instructions for carrying out the method of the first aspect or any one of its possible implementations.

In an eighth aspect, the present application provides a computer-readable storage medium. The computer readable storage medium has stored therein program code for execution by the communication device. The program code comprises instructions for carrying out the method of the second aspect or any one of its possible implementations.

In a ninth aspect, the present application provides a computer-readable storage medium. The computer readable storage medium has stored therein program code for execution by the communication device. The program code comprises instructions for carrying out the method of the third aspect or any one of its possible implementations.

In a tenth aspect, the present application provides a computer program product comprising instructions. The computer program product, when run on a communication apparatus, causes the apparatus to perform the method of the first aspect or any one of its possible implementations.

In an eleventh aspect, the present application provides a computer program product comprising instructions. The computer program product, when run on a communication device, causes the device to perform the method of the second aspect or any one of its possible implementations.

In a twelfth aspect, the present application provides a computer program product containing instructions. The computer program product, when run on a communication apparatus, causes the apparatus to perform the method of the third aspect or any one of its possible implementations.

Drawings

Fig. 1 is a schematic architecture diagram of a communication system to which the communication method of the embodiment of the present application can be applied.

Fig. 2 is a schematic flow chart of a communication method according to an embodiment of the present application.

Fig. 3 is a schematic flow chart of a communication method according to another embodiment of the present application.

Fig. 4 is a schematic flow chart of a communication method according to another embodiment of the present application.

Fig. 5 is a schematic configuration diagram of a communication apparatus according to an embodiment of the present application.

Fig. 6 is a schematic configuration diagram of a communication apparatus according to another embodiment of the present application.

Fig. 7 is a schematic configuration diagram of a communication apparatus according to another embodiment of the present application.

Fig. 8 is a schematic configuration diagram of a communication apparatus according to another embodiment of the present application.

Detailed Description

The technical solution in the present application will be described below with reference to the accompanying drawings.

The technical scheme of the embodiment of the application can be applied to various communication systems, for example: a global system for mobile communications (GSM) system, a Code Division Multiple Access (CDMA) system, a Wideband Code Division Multiple Access (WCDMA) system, a General Packet Radio Service (GPRS), a Long Term Evolution (LTE) system, a LTE Frequency Division Duplex (FDD) system, a LTE Time Division Duplex (TDD), a Universal Mobile Telecommunications System (UMTS), a Worldwide Interoperability for Microwave Access (WiMAX) communication system, a future fifth generation (5G) system, or a new radio NR (NR) system, etc.

Terminal equipment in embodiments of the present application may refer to user equipment, an access terminal, a subscriber unit, a subscriber station, a mobile station, a remote terminal, a mobile device, a user terminal, a wireless communication device, a user agent, or a user device. The terminal device may also be a cellular phone, a cordless phone, a Session Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL) station, a Personal Digital Assistant (PDA), a handheld device with a wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a future 5G network or a terminal device in a future evolved Public Land Mobile Network (PLMN), and the like, which is not limited in this embodiment of the present application.

The network device in this embodiment may be a device for communicating with a terminal device, where the network device may be a Base Transceiver Station (BTS) in a global system for mobile communications (GSM) system or a Code Division Multiple Access (CDMA) system, may also be a base station (NodeB) in a Wideband Code Division Multiple Access (WCDMA) system, may also be an evolved NodeB (eNB) or eNodeB) in an LTE system, may also be a wireless controller in a Cloud Radio Access Network (CRAN) scenario, or may be a relay station, an access point, a vehicle-mounted device, a wearable device, a network device in a future 5G network, or a network device in a future evolved PLMN network, and the like, and the present embodiment is not limited.

In the embodiment of the application, the terminal device or the network device includes a hardware layer, an operating system layer running on the hardware layer, and an application layer running on the operating system layer. The hardware layer includes hardware such as a Central Processing Unit (CPU), a Memory Management Unit (MMU), and a memory (also referred to as a main memory). The operating system may be any one or more computer operating systems that implement business processing through processes (processes), such as a Linux operating system, a Unix operating system, an Android operating system, an iOS operating system, or a windows operating system. The application layer comprises applications such as a browser, an address list, word processing software, instant messaging software and the like. Furthermore, the embodiment of the present application does not particularly limit the specific structure of the execution main body of the method provided by the embodiment of the present application, as long as the communication can be performed according to the method provided by the embodiment of the present application by running the program recorded with the code of the method provided by the embodiment of the present application, for example, the execution main body of the method provided by the embodiment of the present application may be a terminal device or a network device, or a functional module capable of calling the program and executing the program in the terminal device or the network device.

In addition, various aspects or features of the present application may be implemented as a method, apparatus, or article of manufacture using standard programming and/or engineering techniques. The term "article of manufacture" as used herein is intended to encompass a computer program accessible from any computer-readable device, carrier, or media. For example, computer-readable media can include but are not limited to magnetic storage devices (e.g., hard disk, floppy disk, magnetic strips, etc.), optical disks (e.g., Compact Disk (CD), Digital Versatile Disk (DVD), etc.), smart cards, and flash memory devices (e.g., erasable programmable read-only memory (EPROM), card, stick, key drive, etc.). In addition, various storage media described herein can represent one or more devices and/or other machine-readable media for storing information. The term "machine-readable medium" can include, without being limited to, wireless channels and various other media capable of storing, containing, and/or carrying instruction(s) and/or data.

Fig. 1 is a network architecture applied to an embodiment of the present application. As shown in fig. 1, each network element involved in the network architecture is separately described.

1. (radio access network, (R) AN) network element: the method is used for providing a network access function for authorized users in a specific area, and can use transmission tunnels with different qualities according to the level of the users, the requirements of services and the like. The (R) AN network element can manage radio resources, provide access services for the terminal device, and then complete the forwarding of control signals and user data between the terminal device and the core network, and the (R) AN network element can also be understood as a base station in a conventional network.

In the 4G communication system, the (R) AN network element may be AN evolved UMTS terrestrial radio access network (E-UTRAN) network element. In the 5G communication system, the (R) AN network element may be a next generation radio access network (NG-RAN) network element. In the future communication system, the (R) AN network element may still be AN NG-RAN network element, or may also have another name, which is not limited in this application.

2. The access management network element: the method is mainly used for the functions of mobility management, access management, legal monitoring, access authorization/authentication and the like.

In the 4G communication system, the access management network element may be a Mobility Management Entity (MME) network element. In the 5G communication system, the access management network element may be an access and mobility management function (AMF) network element. In a future communication system, the access management network element may still be an AMF network element, or may also have another name, which is not limited in this application.

3. Serving Gateway (SGW) network element: the SGW network element is mainly used for routing and forwarding data packets under the control of the MME, that is, forwarding received user data to a specified PDN Gateway (PGW) network element.

Generally, the SGW network element receives and sends data packets of a GPRS Tunneling Protocol (GTP), and format conversion of the data packets is not required, so the SGW network element may also be considered as a bidirectional transmission channel of the GTP protocol data packets.

4. A user plane network element: for packet routing and forwarding, quality of service (QoS) handling of user plane data, etc.

In the network architecture, the user plane network element may be a fusion node of a User Plane Function (UPF) network element and a PDN gateway user plane function (PGW-U) network element.

For example, in a 4G communication system, the fusion node is configured to implement the function of a PGW-U network element, and interact with an SGW through an S5/S8-U interface; in the 5G communication system, the fusion node is used to implement the function of the UPF network element and provide a service interface to the outside. In future communication systems, the fusion node may have other names or may implement other functions, and the present application is not limited thereto.

5. A session management network element: the method is mainly used for session management, Internet Protocol (IP) address allocation and management of terminal equipment, selection of a termination point capable of managing a user plane function, a policy control and charging function interface, downlink data notification and the like.

In the network architecture, the session management network element may be a fusion node of a Session Management Function (SMF) network element and a PDN gateway control plane function (PGW-C) network element.

For example, in a 4G communication system, the fusion node is used to implement the function of a PGW-C network element, and interacts with an SGW through an S5/S8-C interface; in the 5G communication system, the fusion node is used to implement the function of the SMF network element and provide a service interface to the outside. In future communication systems, the fusion node may have other names or may implement other functions, and the present application is not limited thereto.

6. The strategy control network element: the unified policy framework is used for guiding network behaviors, providing policy rule information for control plane function network elements and the like.

In the network architecture, the policy control network element may be a fusion node of a Policy Control Function (PCF) network element and a Policy and Charging Rules Function (PCRF) network element.

For example, in a 4G communication system, the fusion node is configured to implement a function of a PCRF network element; in the 5G communication system, the fusion node is used to implement the function of the PCF network element and provide a service interface to the outside. In future communication systems, the fusion node may have other names or may implement other functions, and the present application is not limited thereto.

7. Unified data management network element: for handling subscriber identities, access authentication, registration, mobility management, etc.

In the network architecture, the unified data management network element may be a fusion node of a Unified Data Management (UDM) network element and a Home Subscriber Server (HSS) network element.

For example, in a 4G communication system, the fusion node is configured to implement a function of an HSS network element; in the 5G communication system, the fusion node is used to implement the function of the UDM network element and provide a service interface to the outside. In future communication systems, the fusion node may have other names or may implement other functions, and the present application is not limited thereto.

8. The terminal equipment: may include various handheld devices, vehicle-mounted devices, wearable devices, computing devices or other processing devices connected to a wireless modem with wireless communication capabilities, as well as various forms of terminals, Mobile Stations (MSs), terminals (terminals), User Equipment (UEs), soft terminals, etc., such as water meters, electricity meters, sensors, etc.

It is to be understood that the above network elements or functions may be network elements in a hardware device, or may be software functions running on dedicated hardware, or virtualization functions instantiated on a platform (e.g., a cloud platform).

In the network architecture, S1-MME is an interface between E-RTRAN120 network element and MME network element 130; S1-U is an interface between the E-RTRAN120 network element and the SGW network element 140; s11 is an interface between MME network element 130 and SGW network element 140; s6a is an interface between the MME network element 130 and the fusion node 180; S5-C is an interface between SGW network element 140 and fusion node 160; S5-U is an interface between SGW network element 140 and fusion node 150.

In the network architecture, N1 is a reference point between the UE210 and the AMF network element 230, and N2 is a reference point between the NG-RAN network element 220 and the AMF network element 230, and is used for sending a non-access stratum (NAS) message, and the like; n3 is a reference point between the NG-RAN network element 220 and the fusion node 150, and is used for transmitting user plane data and the like; n4 is a reference point between the fusion node 150 and the fusion node 160, and is used to transmit information such as tunnel identification information, data cache indication information, and downlink data notification message of the N3 connection; n7 is a reference point between the fusion node 160 and the fusion node 170, for obtaining policy data; the N8 interface is a reference point between the AMF network element 230 and the fusion node 180, and is used for acquiring user subscription data; n10 is the reference point between the fusion node 160 and the fusion node 180; n11 is a reference point between the AMF network element 230 and the fusion node 160; n15 is a reference point between the AMF network element 230 and the fusion node 170, and is used to obtain policy data; n26 is the reference point between the MME network element 130 and the AMF network element 230.

It should be understood that the network architecture applied to the embodiments of the present application is only an exemplary network architecture, and the network architecture applicable to the embodiments of the present application is not limited thereto, and any network architecture capable of implementing the functions of the network elements described above is applicable to the embodiments of the present application.

Optionally, the network architecture of the embodiment of the present application may further include a network element storage function (NRF) network element or an Unstructured Data Storage Function (UDSF) network element, and the like, which is not limited in the embodiment of the present application.

In this embodiment of the present application, when the above-mentioned fusion node provides a service for the UE, the fusion node may allocate a relevant resource to the UE and send the resource identifier to other network elements, so that the other network elements may find the resource according to the identifier in a subsequent communication process.

It should be understood that, in this application, the above-mentioned resource may be referred to as a session, or may be referred to as a policy session, or may be referred to by other names, and this is not limited by this embodiment of the present application. For convenience of understanding, in the following description, a uniform resource is referred to as a session in the embodiments of the present application.

The fusion node in the network architecture of fig. 1 may support interworking with 5G NFs, and may also support interworking with EPC network elements. In 5GC, the above fusion node may adopt a servitization interface resource definition, and identify a session in SMF by a context reference identifier (SmContextRef); in EPC, the above-mentioned fusion node can use the interface definition of S5/S8-C to identify the session in PGW-C through the full tunnel end identifier (F-TEID) of PGW S5/S8-C.

In the embodiment of the present application, a plurality of the above-mentioned fusion nodes may form a fusion node set (set), for example, a plurality of the fusion nodes 160 may be included in fig. 1, and the plurality of the fusion nodes 160 may form a fusion node set. The above-mentioned fusion node may not be able to provide the service continuously, and at this time, another fusion node in the set is needed to replace the current fusion node to continue the service. For example, in a scenario where a fusion node performs load balancing, or when a current fusion node is powered off, fails, or performs capacity reduction, another fusion node may be needed to replace or partially replace the current fusion node to continue service.

Therefore, the present application provides a communication method, which can enable other fusion nodes to continue to provide services for a session when the fusion nodes cannot continue to provide services for the session.

For convenience of understanding, the following takes the fusion node 160 in the network architecture of fig. 1 as an example to describe the communication method according to an embodiment of the present application. It should be understood that the fusion node 160 is presented herein by way of example only and not limitation, and that the communication method of fig. 2 may be applied to any of the fusion nodes of fig. 1.

Fig. 2 shows an exemplary flowchart of a communication method of one embodiment of the present application, which includes the following steps.

S210, the service gateway determines the identifier of a first session, wherein the first session is a session of a first network element in the network element set which is migrated out of the backup relationship with each other.

The network element set may be a fusion node set of the multiple fusion nodes 160 in fig. 1, and the first network element may be one fusion node of the multiple fusion nodes 160 in fig. 1. The situation that the service cannot be provided continuously may occur in the fusion node in the network element set, and at this time, other fusion nodes in the network element set may replace the current fusion node to continue the service.

Optionally, a plurality of network elements in the network element set may be in a backup relationship with each other. For example, the network element set may include a first network element and a second network element, and the first network element and the second network element may be in a backup relationship with each other. That is, when the first network element cannot continue to provide the service, the second network element may continue to provide the service instead of the first network element. Similarly, when the second network element cannot continue to provide service, the first network element may also continue to provide service in place of the second network element.

For convenience of understanding, the above-mentioned fusion node set is collectively referred to as a network element set, and the fusion nodes in the above-mentioned fusion node set are referred to as network elements, for example, a first network element, a second network element, and the like. It is to be understood that such description is by way of example only and not of limitation.

In this application, sessions in each network element in the network element set may be divided into one or more session groups (pointers), for example, a first network element in the network element set may include multiple session groups.

That is to say, the first network element may include a first session, and the identifier of the first session may include a session group identifier and an intra-session group identifier, where the session group identifier is used to indicate a session group in which the first session is located, and the intra-session group identifier is used to indicate the first session in the session group. At this time, the network element in the network element set may uniquely determine the first session in the network element set according to the identifier of the first session.

In this application, the network element in the network element set may notify, in a message notification manner, the session list supported by each network element in the network element set and the backup network element of each session to other network elements.

For example, on the EPC side, an echo request (echo request) message and an echo reply (echo response) message may be extended, and when the SGW sends the echo request message to the first network element, the first network element may reply to the echo response message, where the message may include a session list supported by each network element in the network element set and a backup network element for each session. Accordingly, after receiving the Echo Response message, the SGW may store the session list supported by each network element in the network element set and the backup network element of each session.

For another example, on the 5GC side, when the first network element registers service with the NRF network element, the NF configuration file (profile) may carry a session list supported by each network element in the network element set and a backup network element of each session. Correspondingly, the 5G NFs may obtain, by calling an discovery (discovery) service of the NRF network element, a session list supported by each network element in the network element set and a backup network element of each session, and store them.

In this application, the network element in the network element set may notify the session list supported by each network element in the network element set and the backup network element of each session to other network elements in a configuration manner.

For example, the session list supported by each network element in the network element set and the backup network element of each session may be configured directly on the relevant network element on the EPC side or the 5GC side. In this case, there is no need to extend the existing standard message.

In this application, the serving gateway may send second information to a mobility management entity, where the second information is used to indicate that the first session is migrated out of the first network element.

In a possible implementation manner, the serving gateway may send the second information to a mobility management entity through a PGW restart notification (PGW restart notification) message.

In another possible implementation manner, the serving gateway may send the second information to a mobility management entity through an update bearer request (update bearer request) message.

Optionally, the message may include a session list supported by each network element in the network element set and a backup network element of each session.

In this application, the mobility management entity may send the third information to a serving gateway, where the third information may be used to trigger the serving gateway to send the first information to the second network element.

Optionally, the mobility management entity may send the third information to the serving gateway by modifying a bearer request (modify bearer request) message.

In this application, the first information or the third information may include identification information of the second network element, where the second network element may be a backup network element of the first session in the first network element. Optionally, the identification information of the second network element may be an IP address of the second network element.

Optionally, the second network element may configure a plurality of IP addresses. For example, the second network element may configure 2 IP addresses: IP #2 and IP-BK # 2. Wherein IP #2 may be used to process the service request in the second network element, and IP-BK #2 may serve the first session in the first network element.

At this time, when the first network element cannot continue to provide the service, the serving gateway or the mobility management entity may update the IP address in the PGW S5/S8-C F-TEID to IP-BK #2, so that the second network element continues to serve the first session instead of the first network element.

S220, the serving gateway determines first information according to the identifier of the first session, where the first information is used to indicate a second network element in the network element set to serve the first session, and the identifier of the first session can uniquely indicate the first session in the first network element and the second network element.

In this application, in response to the third information, the serving gateway may determine the first information according to an identifier of the first session.

S230, the serving gateway sends the first information to the second network element.

In this application, after receiving the first information, the second network element may continue to provide services for the first session.

Fig. 3 illustrates an exemplary flow chart of a communication method of one embodiment of the present application. Fig. 3 illustrates a flow of the second network element replacing the first network element to continue the service when the first network element cannot continue to provide the service by taking a failure of the first network element as an example. S. the

1. The first network element may register a service with an NRF network element, where the NF profile may carry a session list supported by each network element in the network element set and a backup network element of each session;

2. the 5G NFs can obtain a session list supported by each network element in the network element set and a backup network element of each session by calling a discovery (discovery) service of the NRF network element, and store the session list and the backup network element of each session;

3. the SGW may send an echo request message to the first network element;

4. the first network element may reply to an echo response message, where the message may include a session list supported by each network element in the network element set and a backup network element of each session;

5. optionally, after receiving the Echo Response message, the SGW may store a session list supported by each network element in the network element set and a backup network element of each session;

6. the first network element is failed;

7. the NRF notifies the 5G NFs that the first network element fails after detecting that the first network element fails, correspondingly, the 5G NFs identifies that the first network element is unavailable after receiving the notification, and sends a message of a session in the first network element to a second network element for processing after subsequently receiving the message;

8. After the SGW detects that the first network element has a fault, the SGW identifies that the first network element is unavailable;

9. the SGW sends a PGW restart notification message to the MME, wherein the message comprises a session list supported by each network element in the network element set and a backup network element of each session, and if a configuration mode is adopted, no indication is needed in the message;

10. optionally, the MME stores a session list supported by each network element in the network element set and a backup network element of each session;

11. the MME receives a service request (service request) initiated by the UE, and correspondingly, the MME performs authentication and RAN side radio bearer resource processing;

12. because the SMF + PGW-C #1 node is unavailable, the MME may extract an identifier of a first session from the PGW S5/S8-C F-TEID, and determine that a second network element is a backup network element of the first network element according to the stored session context information, at this time, the MME may update an IP address in the PGW S5/S8-C F-TEID to an IP address of the second network element;

13. the MME sends a modify bearer request message to the SGW to activate the SGW to update PGW S5/S8-C F-TEID in a corresponding context;

14. because the SMF + PGW-C #1 node is unavailable, the SGW may extract the identifier of the first session from the PGW S5/S8-C F-TEID, and determine that the second network element is a backup network element of the first network element according to the stored session context information, at this time, the SGW may update the IP address in the PGW S5/S8-C F-TEID to the IP address of the second network element;

15. And the SGW sends a modify bearer request message to a second network element to indicate the second network element to serve the first session.

Fig. 4 shows an exemplary flowchart of a communication method of another embodiment of the present application, which includes the following steps.

S410, the second network element determines that the first session is migrated from the first network element to the second network element, and the first network element and the second network element belong to a network element set in a backup relationship with each other.

The network element set may be a fusion node set of the plurality of fusion nodes 160 in fig. 1, the first network element may be one fusion node of the plurality of fusion nodes 160 in fig. 1, and the first network element may be another fusion node of the plurality of fusion nodes 160 in fig. 1.

Optionally, the multiple network elements in the network element set may be in a backup relationship with each other, and a situation that the network element may not be able to continue providing service may occur, and at this time, other network elements in the network element set may replace the current network element to continue providing service.

In this application, the second network element may detect that the first session is migrated out of the first network element. For example, when the first network element fails, the second network element may detect that the first network element fails.

Alternatively, when the first network element fails, the NRF network element may notify the second network element that the first network element fails.

For example, the network element set may include a first network element and a second network element, and the first network element and the second network element may be in a backup relationship with each other. That is, when the first network element cannot continue to provide the service, the second network element may continue to provide the service instead of the first network element. Similarly, when the second network element cannot continue to provide service, the first network element may also continue to provide service in place of the second network element.

In this application, when the first network element fails, the second network element may obtain session context information stored by the UDSF network element, and determine a session or a session group migrated to the second network element according to the session context information. The session context information is a session list supported by each network element in the network element set and a backup network element of each session.

S420, the second network element allocates a session identifier for the first session, where the session identifier can uniquely indicate the first session in the second network element.

The identifier of the first session may include a session group identifier and an intra-session group identifier, where the session group identifier is used to indicate a session group in which the first session is located, and the intra-session group identifier is used to indicate the first session in the session group.

In this application, when the first session is migrated from a first network element to the second network element, the second network element may reassign a session identifier to the first session, where the session identifier may uniquely indicate the first session in the second network element.

For example, the second network element reassigns the PGW S5/S8-C F-TEID for the first session, and the PGW S5/S8-C F-TEID can uniquely indicate the first session in the second network element.

In this application, the second network element may send fourth information to the serving gateway, where the fourth information may be used to indicate that the first session is migrated to the second network element.

Optionally, the second network element may send the fourth information to the serving gateway through an update bearer request message.

In this application, when the first network element cannot continue to provide services, the second network element may detect that the first network element stops providing services; or the NRF network element may notify the second network element that the first network element stops providing services. At this time, the second network element may reallocate PGW S5/S8-C F-TEID for the session in the first network element. The second network element may send an update bearer request message to the serving gateway to request the serving gateway to update the PGW S5/S8-C F-TEID in the corresponding context. Accordingly, after receiving the message, the service may update the PGW S5/S8-C F-TEID in the corresponding context, and then send an update bearer request message to the mobility management entity to request the mobility management entity to update the PGW S5/S8-C F-TEID in the corresponding context.

Optionally, the update bearer request message that the second network element may send to the service gateway may include fourth information. The second information may be included in an update bearer request message sent by the serving gateway to the mobility management entity.

In this application, the fourth information may be determined by the second network element according to session context information stored in the UDSF network element. The session context information may be a session list supported by each network element in the network element set and a backup network element of each session.

Optionally, when the first network element cannot continue to provide the service, the second network element may read the session context information by the UDSF network element.

In this application, in response to the fourth information, the serving gateway may determine the first information according to an identity of the first session.

According to the communication method provided in the embodiment of the present application, the second network element determines that the first session is migrated from the first network element to the second network element, at this time, the second network element assigns a session identifier to the first session, and the session identifier can uniquely indicate the first session in the second network element, so that when the first network element cannot continue to provide services for the first session, the second network element can continue to provide services for the first session.

Fig. 5 is a schematic block diagram of a communication apparatus 500 according to an embodiment of the present application. It should be understood that the communication device 500 is merely an example. The communication apparatus of the embodiment of the present application may further include other modules or units, or include modules having functions similar to those of the respective modules in fig. 5, or not include all the modules in fig. 5.

In an embodiment of the present application, the processing unit 510 is configured to determine an identifier of a first session, where the first session is a session migrated out of a first network element in a set of network elements that are in a backup relationship with each other;

the processing unit 510 is further configured to determine first information according to an identifier of the first session, where the first information is used to indicate that a second network element in the network element set serves the first session, and the identifier of the first session can uniquely indicate the first session in the first network element and the second network element;

a sending unit 520, configured to send the first information to the second network element.

Optionally, the identifier of the first session includes a session group identifier and an intra-session group identifier, where the session group identifier is used to indicate a session group in which the first session is located, and the intra-session group identifier is used to indicate the first session in the session group.

Optionally, the sending unit 520 is further configured to send second information to a mobility management entity, where the second information is used to indicate that the first session is migrated out of the first network element.

Optionally, the communication apparatus 500 further includes a receiving unit 530, configured to receive third information sent by the mobility management entity, where the third information is used to trigger the serving gateway to send the first information to the second network element.

Optionally, the third information includes identification information of the second network element.

Optionally, the processing unit 510 is specifically configured to: in response to the third information, determining the first information according to the identity of the first session.

Optionally, the first information includes identification information of the second network element.

Fig. 6 is a schematic block diagram of a communication apparatus 600 according to an embodiment of the present application. It should be understood that communications apparatus 600 is only one example. The communication device of the embodiment of the present application may further include other modules or units, or include modules having functions similar to those of the respective modules in fig. 6, or not include all the modules in fig. 6.

In an embodiment of the present application, the processing unit 610 is configured to determine an identifier of a first session, where the first session is a session migrated out of a first network element in a network element set in a backup relationship with each other;

the processing unit 610 is further configured to determine third information according to the identifier of the first session, where the third information is used to indicate that the first session is migrated to the second network element, and the identifier of the first session can uniquely indicate the first session in the first network element and the second network element;

A sending unit 620, configured to send the third information to the serving gateway.

Optionally, the communication apparatus 600 further includes a receiving unit 630, configured to receive second information sent by the serving gateway, where the second information is used to indicate that the first session is migrated out of the first network element.

Optionally, the processing unit 610 is specifically configured to: and responding to the second information, and determining third information according to the identification of the first session.

Fig. 7 is a schematic block diagram of a communication apparatus 700 according to an embodiment of the present application. It should be understood that communication apparatus 700 is merely an example. The communication apparatus of the embodiment of the present application may further include other modules or units, or include modules having functions similar to those of the respective modules in fig. 7, or not include all the modules in fig. 7.

In an embodiment of the present application, the processing unit 710 is configured to determine that a first session is migrated from a first network element to a second network element, where the first network element and the second network element belong to a set of network elements that are in a backup relationship with each other;

The processing unit 710 is further configured to assign a session identifier to the first session, where the session identifier is capable of uniquely indicating the first session in the second network element.

Optionally, the communication apparatus 700 further includes a sending unit 720, configured to send fourth information to a serving gateway, where the fourth information is used to indicate that the first session is migrated to the second network element.

Optionally, the fourth information is determined by the second network element according to session context information stored by an unstructured data storage function network element.

Fig. 8 is a schematic structural diagram of a network element according to an embodiment of the present application. It should be understood that the communication apparatus 800 shown in fig. 8 is only an example, and the communication apparatus of the embodiment of the present application may further include other modules or units, or include modules having functions similar to those of the respective modules in fig. 8.

Communication device 800 may include one or more processors 810, one or more memories 820, a receiver 830, and a transmitter 840. The receiver 830 and the transmitter 840 may be integrated together, referred to as a transceiver. The memory 820 is used to store program codes executed by the processor 810. The memory 820 may be integrated into the processor 810, or the processor 810 may be coupled to one or more memories 820 for fetching instructions from the memories 820.

In one embodiment, processor 810 may be used to implement operations or steps capable of being implemented by processing unit 510 in fig. 5, transmitter 840 may be used to implement operations or steps capable of being implemented by transmitting unit 520 in fig. 5, and receiver 830 may be used to implement operations or steps capable of being implemented by receiving unit 530 in fig. 5.

In another embodiment, processor 810 may be used to implement operations or steps capable of being implemented by processing unit 610 in fig. 6, transmitter 840 may be used to implement operations or steps capable of being implemented by transmitting unit 620 in fig. 6, and receiver 830 may be used to implement operations or steps capable of being implemented by receiving unit 630 in fig. 6.

In another embodiment, processor 810 may be used to implement operations or steps capable of being implemented by processing unit 710 of FIG. 7, and transmitter 840 may be used to implement operations or steps capable of being implemented by transmitting unit 720 of FIG. 7.

It should be understood that the processor in the embodiments of the present application may be a Central Processing Unit (CPU), and the processor may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

It will also be appreciated that the memory in the embodiments of the subject application can be either volatile memory or nonvolatile memory, or can include both volatile and nonvolatile memory. The non-volatile memory may be a read-only memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an electrically Erasable EPROM (EEPROM), or a flash memory. Volatile memory can be Random Access Memory (RAM), which acts as external cache memory. By way of example, but not limitation, many forms of Random Access Memory (RAM) are available, such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), Enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct bus RAM (DR RAM).

The above-described embodiments may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, the above-described embodiments may 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 or computer programs. The procedures or functions described in accordance with the embodiments of the present application are produced in whole or in part when the computer instructions or the computer program are loaded or executed on a computer. The computer may be a general purpose computer, a special purpose computer, a network of computers, 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 one website, computer, server, or data center to another website, computer, server, or data center by wire (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains one or more collections of available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. The semiconductor medium may be a solid state disk.

It should be understood that the term "and/or" herein is merely one type of association relationship that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

It should be understood that, in the various embodiments of the present application, the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It can be clearly understood by those skilled in the art that, for convenience and simplicity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one type of logical functional division, and other divisions may be realized in practice, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

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

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a read-only memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method of communication, comprising:

the service gateway determines an identifier of a first session, wherein the first session is a session of a first network element in a network element set which is migrated out of the network element set in a backup relationship with each other, and the network element set is a set of fusion nodes of a plurality of session management network elements and a public data network gateway control panel function network element;

the serving gateway determines first information according to an identifier of the first session and session context information of the first session, where the first information is used to indicate a second network element in the network element set to serve the first session, the identifier of the first session may uniquely indicate the first session in the first network element and the second network element, and the identifier of the first session includes a full tunnel endpoint identifier F-TEID;

and the service gateway sends the first information to the second network element.

2. The communication method according to claim 1, wherein the identifier of the first session comprises a talkgroup identifier and an intratalkgroup identifier, and the talkgroup identifier is used to indicate a talkgroup in which the first session is located, and the intratalkgroup identifier is used to indicate the first session in the talkgroup.

3. The communication method according to claim 1 or 2, wherein the communication method further comprises:

and the service gateway sends second information to a mobility management entity, wherein the second information is used for indicating that the first session is migrated out of the first network element.

4. A communication method according to claim 3, characterized in that it further comprises:

and the service gateway receives third information sent by the mobility management entity, wherein the third information is used for triggering the service gateway to send the first information to the second network element.

5. The communication method according to claim 4, wherein the serving gateway determines the first information according to the identifier of the first session, and comprises:

and responding to the third information, and determining the first information by the service gateway according to the identification of the first session.

6. The communication method according to claim 1 or 2, wherein the first information comprises identification information of the second network element.

7. A method of communication, comprising:

a mobility management entity determines an identifier of a first session, wherein the first session is a session of a first network element in a network element set which is migrated out of the first session in a backup relationship with each other, and the network element set is a set of fusion nodes of a plurality of session management network elements and a gateway control panel function network element of a public data network;

The mobility management entity determines third information according to the identifier of the first session and session context information of the first session, where the third information is used to indicate that the first session is migrated to a second network element in the network element set, where the identifier of the first session can uniquely indicate the first session in the first network element and the second network element, and the identifier of the first session includes a full tunnel endpoint identifier F-TEID;

and the mobility management entity sends the third information to a service gateway.

8. The communication method according to claim 7, wherein the identifier of the first session comprises a talkgroup identifier and an intratalkgroup identifier, and wherein the talkgroup identifier is used for indicating a talkgroup in which the first session is located, and wherein the intratalkgroup identifier is used for indicating the first session in the talkgroup.

9. The communication method according to claim 7 or 8, wherein the communication method further comprises:

and the mobility management entity receives second information sent by the serving gateway, where the second information is used to indicate that the first session is migrated out of the first network element.

10. The communication method according to claim 9, wherein the determining, by the mobility management entity, the third information according to the identity of the first session includes:

And responding to the second information, and the mobility management entity determines third information according to the identification of the first session.

11. The communication method according to claim 7 or 8, wherein the third information comprises identification information of the second network element.

12. A method of communication, comprising:

the second network element acquires session context information stored by the unstructured data storage function network element;

the second network element determines that a first session is migrated from a first network element to the second network element according to the session context information, the first network element and the second network element belong to network element sets which are in a backup relationship with each other, and the network element sets are sets of fusion nodes of a plurality of session management network elements and public data network gateway control panel function network elements;

and the second network element allocates a session identifier for the first session, the session identifier can uniquely indicate the first session in the second network element, and the session identifier comprises a full-tunnel endpoint identifier F-TEID.

13. The communication method according to claim 12, further comprising:

and the second network element sends fourth information to a service gateway, wherein the fourth information is used for indicating that the first session is migrated to the second network element.

14. The communications method according to claim 13, wherein the fourth information is determined by the second network element based on session context information stored by the unstructured-data storage function network element.

15. A communications apparatus, comprising:

the processing unit is used for determining an identifier of a first session, wherein the first session is a session of a first network element in a network element set which is migrated out of a backup relationship with each other, and the network element set is a set of fusion nodes of a plurality of session management network elements and a gateway control panel functional network element of a public data network;

the processing unit is further configured to determine first information according to an identifier of the first session and session context information of the first session, where the first information is used to indicate a second network element in the network element set to serve the first session, where the identifier of the first session can uniquely indicate the first session in the first network element and the second network element, and the identifier of the first session includes a full tunnel endpoint identifier F-TEID;

a sending unit, configured to send the first information to the second network element.

16. The communications apparatus of claim 15, wherein the identification of the first session comprises a talkgroup identification and an intra-talkgroup identification, the talkgroup identification indicating a talkgroup in which the first session is located, and the intra-talkgroup identification indicating the first session in the talkgroup.

17. The communications apparatus according to claim 15 or 16, wherein the sending unit is further configured to send second information to a mobility management entity, where the second information is used to indicate that the first session is migrated out of the first network element.

18. The communications apparatus as claimed in claim 17, further comprising a receiving unit, configured to receive third information sent by the mobility management entity, where the third information is used to trigger the sending unit to send the first information to the second network element.

19. The communications device according to claim 18, wherein the processing unit is specifically configured to:

in response to the third information, determining the first information according to the identity of the first session.

20. The communication apparatus according to claim 15 or 16, wherein the first information comprises identification information of the second network element.

21. A communications apparatus, comprising:

a processing unit, configured to determine an identifier of a first session, where the first session is a session of a first network element in a network element set migrated out of a backup relationship with each other, and the network element set is a set of fusion nodes of a plurality of session management network elements and a gateway control panel function network element of a public data network;

The processing unit is further configured to determine third information according to an identifier of the first session and session context information of the first session, where the third information is used to indicate that the first session is migrated to a second network element in the network element set, where the identifier of the first session can uniquely indicate the first session in the first network element and the second network element, and the identifier of the first session includes a full tunnel endpoint identifier F-TEID;

and the sending unit is used for sending the third information to the service gateway.

22. The communications apparatus of claim 21, wherein the identification of the first session comprises a talkgroup identification and an intratalkgroup identification, the talkgroup identification is used for indicating a talkgroup in which the first session is located, and the intratalkgroup identification is used for indicating the first session in the talkgroup.

23. The apparatus according to claim 21 or 22, wherein the apparatus further comprises a receiving unit, configured to receive second information sent by the serving gateway, where the second information is used to indicate that the first session is migrated out of the first network element.

24. The communications device according to claim 23, wherein the processing unit is specifically configured to:

Third information is determined from the identity of the first session in response to the second information.

25. The communications apparatus according to claim 21 or 22, wherein the third information comprises identification information of the second network element.

26. A communications apparatus, comprising:

the processing unit is used for acquiring the session context information stored by the network element with the unstructured data storage function;

the processing unit is further configured to determine, according to the session context information, that a first session is migrated from a first network element to a second network element, where the first network element and the second network element belong to a network element set that are in a backup relationship with each other;

the processing unit is further configured to allocate a session identifier to the first session, where the session identifier is capable of uniquely indicating the first session in the second network element, and the session identifier includes a full tunnel endpoint identifier F-TEID.

27. The apparatus according to claim 26, wherein the apparatus further comprises a sending unit configured to send fourth information to a serving gateway, and the fourth information is used to indicate that the first session is migrated to the second network element.

28. A communications device according to claim 27, wherein the fourth information is determined by the second network element based on session context information stored by the unstructured data storage function network element.

29. A computer-readable storage medium, wherein a program code for execution by a communication apparatus is stored therein, the program code comprising instructions for performing the communication method of any one of claims 1 to 14.