CN114915614A

CN114915614A - Method and device for recovering IMS service

Info

Publication number: CN114915614A
Application number: CN202210471839.8A
Authority: CN
Inventors: 陈靖; 秦存秀
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-12-20
Filing date: 2019-12-20
Publication date: 2022-08-16
Anticipated expiration: 2039-12-20
Also published as: WO2021120744A1; CN113098822B; CN113098822A; CN114915614B

Abstract

The application relates to the technical field of communication, and discloses a method and a device for recovering an IMS service. The method comprises the following steps: if the user data management network node determines that the IMS session of the terminal equipment fails, first indication information is sent to the mobile management network node and/or the session management network node, the first indication information is used for indicating that the IMS session of the terminal equipment fails, and then the mobile management network node and/or the session management network node can reestablish the IMS session for the terminal equipment so as to recover the IMS service of the terminal equipment. By adopting the scheme, the mobile management network node and/or the session management network node are/is triggered by the user data management network node to reestablish the IMS session of the terminal equipment, so that the IMS service of the terminal equipment is restored in time, the IMS session of the terminal equipment can be reestablished more specifically, and the time delay for restoring the IMS service is effectively reduced.

Description

Method and device for recovering IMS service

The present application is a divisional application, the original application having application number 201911330900.1, the original application date being 2019, 12 and 30, the entire content of the original application being incorporated by reference in the present application.

Technical Field

The present application relates to the field of communications technologies, and in particular, to a method and an apparatus for recovering an IMS service.

Background

An Internet Protocol (IP) multimedia subsystem (IMS) is a network system for providing multimedia services in an IP network, and can provide various multimedia services, such as voice call, video call, and the like, for a terminal device through the IMS.

Taking voice call as an example, a calling terminal device may initiate a call request to a called terminal device through a Packet Switched (PS) network, and after receiving the call request, if the call request is successfully responded, the calling terminal device and the called terminal device may perform voice call. However, the IMS service may fail due to a failure scenario (e.g., a failure of a network entity in the PS network or a network failure between two network entities that need to communicate). Therefore, how to recover the IMS service of the terminal device in time and avoid the long interruption time of the IMS service from affecting the user experience still needs further research.

Disclosure of Invention

The application provides a method and a device for recovering an IMS service, which are used for recovering the IMS service of terminal equipment in time and avoiding the influence on user experience caused by long interruption time of the IMS service.

In a first aspect, an embodiment of the present application provides a method for recovering an IMS service, where the method may be applied to a device for recovering an IMS service, where the device may be an SDMN or a chip disposed in the SDMN. Taking the method as an example of being applicable to the SDMN, in the method, the SDMN determines that the IMS session of the terminal equipment fails, and then sends first indication information to the MMN and/or the SMN, wherein the first indication information is used for indicating that the IMS session of the terminal equipment fails, and the IMS session is used for bearing the IMS service of the terminal equipment.

By adopting the scheme, the MMN and/or the SMN are triggered by the SDMN to reestablish the IMS session of the terminal equipment, so that the IMS service of the terminal equipment is restored in time, the IMS session of the terminal equipment can be reestablished more specifically, and the time delay for restoring the IMS service is effectively reduced.

In one possible design, the SDMN determining that the IMS session for the terminal device failed comprises: and the SDMN receives second indication information from the S-CSCF entity, wherein the second indication information is used for indicating the IMS session failure of the terminal equipment.

By adopting the scheme, after the P-CSCF entity determines that the called flow processing fails, a failure response (indicating that the IMS session of the terminal equipment fails) can be returned to the S-CSCF entity, and then the S-CSCF entity informs the SDMN, so that the SDMN can timely know the IMS session failure of the terminal equipment.

In one possible design, the second indication information is included in a registration notification request or a de-registration notification request received by the SDMN from the S-CSCF entity.

In one possible design, the SDMN sends first indication information to the MMN, including: and if the SDMN determines that the SMN does not successfully recover the IMS session of the terminal equipment, the SDMN sends first indication information to the MMN.

By adopting the method, the SDMN sends the first indication information to the MMN under the condition that the SMN does not successfully recover the IMS session of the terminal equipment, and can not send the first indication information to the MMN under the condition that the SMN successfully recovers the IMS session of the terminal equipment, thereby effectively saving signaling overhead.

In one possible design, the SDMN determining that the SMN did not successfully resume the IMS session for the terminal device comprises: SDMN determines SMN failure; or the SDMN sends the first indication information to the SMN, and does not receive a response message of the SMN within a preset time period; or, the SDMN sends the first indication information to the SMN and receives a response message from the SMN, wherein the response message carries a reason value for unsuccessfully recovering the IMS session.

In one possible design, the method further includes: SDMN receives first information sent by MMN, the first information is used for requesting IMS session failure event of the subscribing terminal device.

In one possible design, the SDMN receives first information from the MMN, including: the SDMN receives a first user context management registration request from the MMN, the first user context management registration request including first information.

By adopting the method, the MMN can request to subscribe the IMS session failure event of the terminal equipment when the terminal equipment registers to the MMN.

In one possible design, the method further includes: the SDMN receives second information from the SMN, wherein the second information is used for requesting the IMS session failure event of the subscription terminal equipment.

In one possible design, the SDMN receives the second information from the SMN, including: the SDMN receives a second user context management registration request from the SMN, the second user context management registration request including second information.

By adopting the method, the SMN can request to subscribe the IMS session failure event of the terminal equipment when the terminal equipment requests the SMN to establish the session.

In a second aspect, an embodiment of the present application provides a method for recovering an IMS service, where the method may be applied to a device for recovering an IMS service, where the device may be an MMN or a chip disposed in the MMN. Taking the method as an example for being applied to the MMN, in the method, if the MMN determines that the IMS session of the terminal device fails, the IMS session is reestablished for the terminal device, and the IMS session is used for carrying the IMS service of the terminal device.

In one possible design, the MMN determining that the IMS session of the terminal device failed includes: the MMN determines that an SMN associated with the IMS session fails; or the MMN receives first indication information from the SDMN, wherein the first indication information is used for indicating the IMS session failure of the terminal equipment.

In one possible design, the method further includes: the MMN sends first information to the SDMN, wherein the first information is used for requesting an IMS session failure event of the subscription terminal equipment.

In one possible design, the MMN sends first information to the SDMN, including: the MMN sends a first user context management registration request to the SDMN, the first user context management registration request including first information.

In one possible design, the MMN reestablishes the IMS session for the terminal device, including: and the MMN sends third indication information to the terminal equipment, wherein the third indication information is used for indicating the terminal equipment to reestablish the IMS session.

In one possible design, the third indication information includes state information of the IMS session, and the state information of the IMS session is used to indicate that the state of the IMS session is an inactive state.

In one possible design, the MMN sends the third indication information to the terminal device, including: and the MMN sends a configuration updating command to the terminal equipment, wherein the configuration updating command comprises third indication information.

In a third aspect, an embodiment of the present application provides a method for recovering an IMS service, where the method may be applied to a device for recovering an IMS service, where the device may be an SMN or a chip disposed in an SMN. Taking the method as an example, in the method, the SMN receives first indication information from the SDMN, the first indication information is used for indicating that an IMS session of the terminal device fails, and further reestablishing the IMS session for the terminal device, the IMS session is used for carrying an IMS service of the terminal device;

in one possible design, the method further includes: the SMN sends second information to the SDMN, wherein the second information is used for requesting the IMS session failure event of the subscription terminal equipment.

In one possible design, the SMN sends the second information to the SDMN, comprising: the SMN sends a second user context management registration request to the SDMN, the second user context management registration request including the second information.

In a fourth aspect, an embodiment of the present application provides a method for recovering an IMS service, where the method may be applied to a device for recovering an IMS service, and the device may be a terminal device or a chip disposed in the terminal device. Taking the method as an example of being applied to the terminal device, in the method, the terminal device receives third indication information from the MMN, where the third indication information is used to indicate the terminal device to reestablish the IMS session, and further reestablish the IMS session according to the third indication information.

In one possible design, the terminal device receives third indication information from the MMN, including: and the terminal equipment receives a configuration updating command from the MMN, wherein the configuration updating command comprises third indication information.

It should be noted that, since the method for recovering an IMS service described in the second aspect, the third aspect, and the fourth aspect corresponds to the method for recovering an IMS service described in the first aspect, for the relevant beneficial effects of the methods for recovering an IMS service described in the second aspect, the third aspect, and the fourth aspect, reference may be made to the first aspect, and details are not described here.

In a fifth aspect, the present application provides an apparatus for recovering an IMS service, where the apparatus has a function of implementing any one of the possible designs of the first aspect to the fourth aspect, for example, the apparatus includes a module or a unit or a means (means) corresponding to the step involved in executing any one of the possible designs of the first aspect to the fourth aspect, and the function or the unit or the means may be implemented by software, or implemented by hardware executing corresponding software.

In one possible design, the apparatus for recovering the IMS service includes a processing unit, and a communication unit, where the communication unit may be configured to send and receive signals to and from another apparatus to implement communication between the apparatus and the other apparatus; the processing unit may be adapted to perform some internal operations of the apparatus. The functions performed by the processing unit, the communication unit may correspond to the steps involved in any one of the possible designs of the first to fourth aspects described above.

In one possible design, the apparatus for recovering an IMS service includes a processor, and may further include a transceiver, where the transceiver is configured to transmit and receive signals, and the processor executes program instructions to implement the method in any possible design or implementation manner of the first to fourth aspects. Wherein the apparatus may further comprise one or more memories for coupling with the processor. The one or more memories may be integrated with the processor or separate from the processor, which is not limited in this application. The memory may hold the necessary computer programs or instructions to implement the functions referred to in the above first to fourth aspects. The processor may execute a computer program or instructions stored by the memory that, when executed, cause the apparatus to implement the method of any possible design or implementation of the first to fourth aspects described above.

In one possible design, the apparatus for restoring IMS services includes a processor and a memory, and the memory may store computer programs or instructions necessary to implement the functions of the first to fourth aspects. The processor may execute a computer program or instructions stored by the memory that, when executed, cause the apparatus to implement the method of any possible design or implementation of the first to fourth aspects described above.

In one possible design, the apparatus for recovering IMS services includes at least one processor and an interface circuit, where the at least one processor is configured to communicate with other apparatuses through the interface circuit, and to perform the method in any possible design or implementation manner of the first aspect to the fourth aspect.

In a sixth aspect, this application further provides a computer storage medium storing a software program that, when read and executed by one or more processors, can implement the method provided by any one of the possible designs of the first to fourth aspects.

In a seventh aspect, embodiments of the present application further provide a computer program, which when executed on a computer, causes the computer to perform the method provided by any one of the possible designs of the first aspect to the fourth aspect.

In an eighth aspect, embodiments of the present application further provide a chip, where the chip is configured to read a computer program stored in a memory, and perform the method provided by any one of the possible designs of the first aspect to the fourth aspect.

In a ninth aspect, an embodiment of the present application provides a chip system, where the chip system includes a processor, and the apparatus for supporting IMS service recovery implements the functions referred to in the foregoing aspects. In one possible design, the system-on-chip further includes a memory for storing program instructions and data necessary for the management device. The chip system may be formed by a chip, or may include a chip and other discrete devices.

Drawings

Fig. 1 is a schematic diagram of a network architecture to which the present invention is applied;

FIG. 2a is a schematic diagram of another network architecture to which the present invention is applied;

FIG. 2b is a schematic diagram of another network architecture to which the present invention is applied;

fig. 3a is a schematic view of a service processing flow of the called terminal device;

fig. 3b is a schematic view of another service processing flow of the called terminal device;

fig. 4a is a schematic diagram of a PDU session establishment procedure provided in an embodiment of the present application;

fig. 4b is a schematic diagram of a PDU session release process provided in an embodiment of the present application;

fig. 5 is a schematic format diagram of a PDU session status cell according to an embodiment of the present application;

fig. 6 is a flowchart illustrating a method for recovering an IMS service according to an embodiment of the present application;

fig. 7 is a flowchart illustrating a method for recovering an IMS service according to a second embodiment of the present application;

FIG. 8 is a possible exemplary block diagram of the devices involved in the embodiments of the present application;

fig. 9 is a schematic diagram of an apparatus for recovering an IMS service according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.

Fig. 1 is a schematic diagram of a network architecture to which the present invention is applied. As shown in fig. 1, the network architecture may include a terminal device, a PS network, and an IMS. IMS can provide various multimedia services such as audio, video, text, and data for a terminal device based on a PS network, and can be understood as services carried by a Circuit Switched (CS) network, such as voice telephony, video telephony, short messages, and the like, which can be collectively referred to as IMS services, based on the PS network.

The terminal device, IMS and PS networks are described below, respectively.

(1) Terminal device

The terminal device may also be referred to as a User Equipment (UE), and may be deployed on land, including indoors or outdoors, in a hand-held manner, or in a vehicle-mounted manner; can also be deployed on the water surface (such as a ship and the like); and may also be deployed in the air (e.g., airplanes, balloons, satellites, etc.). The terminal device may be a mobile phone (mobile phone), a tablet (pad), a computer with wireless transceiving function, a Virtual Reality (VR) device, an Augmented Reality (AR) device, a wireless device in industrial control (industrial control), a wireless device in self driving (self driving), a wireless device in remote medical (remote medical), a wireless device in smart grid (smart grid), a wireless device in transportation safety (transportation safety), a wireless device in smart city (smart city), a wireless device in smart home (smart home), and so on.

(2)IMS

The IMS may include a proxy-call session control function (P-CSCF) entity and a serving-call session control function (S-CSCF) entity.

The P-CSCF entity is an edge network node between the PS network and the IMS, and interacts with the terminal equipment through a user plane of the PS network. Further, the P-CSCF entity is the first point of connection of the PS network to the IMS, i.e. the first point of contact of the terminal device in the IMS. The role of the P-CSCF entity in IMS is similar to the execution of proxy services, and information from or sent to the terminal device needs to be forwarded through the P-CSCF entity. The P-CSCF entity is responsible for sending authentication requests in the IMS, forwarding the authenticated requests to the specified targets, and processing and forwarding the reply information.

The S-CSCF entity is a service processing node of the IMS and is responsible for IMS registration of the terminal equipment and related processing of calling and called services.

Although not shown, other possible entities may also be included in the IMS, such as an interrogating-call session control function (I-CSCF) entity, which may connect an S-CSCF entity and a P-CSCF entity for providing a user with access to the home network; when the terminal equipment roams to other networks, the terminal equipment sends a message to the P-CSCF entity, and the P-CSCF entity can forward the message from the terminal equipment to the I-CSCF entity and send the message from the terminal equipment to the S-CSCF entity through the I-CSCF entity.

(3) PS network

The PS network may include a user data management network node (SDMN), a policy management network node (PMN), a session management network node (SMN), a user plane network node (UPN), and a mobile management network node (MMN). Although not shown, other possible nodes may also be included in the PS network.

For example, the PS network may also be referred to as an operator network or a mobile communication network, and is mainly a network in which a Mobile Network Operator (MNO) provides a mobile broadband access service for a user. The operator network described in the embodiment of the present application may be a network meeting the requirements of the third generation partnership project (3 GPP) standard, which is referred to as a 3GPP network for short. Typically, the 3GPP network is operated by an operator, including but not limited to a fifth generation mobile communication technology (5th-generation, 5G) network, a fourth generation mobile communication technology (4th-generation, 4G) network, and so on. Among them, the 5G network may also be referred to as a New Radio (NR) network, and the 4G network may also be referred to as a Long Term Evolution (LTE) network.

If the PS network is a 4G network, as shown in fig. 2a, the function of the SDMN may be implemented by a Home Subscriber Server (HSS), the function of the PMN may be implemented by a Policy and Charging Rule Function (PCRF) entity, the function of the SMN may be implemented by a packet data network gateway control plane function (PGW-C) entity and a serving gateway function (SGW-C) entity, the function of the UPN may be implemented by a packet data network gateway user plane function (PGW-U) entity and a serving gateway user plane function (MME) entity, and the function of the n may be implemented by a MME (mobility management entity, MME) entity.

If the PS network is a 5G network, as shown in fig. 2b, the function of the SDMN may be implemented by an Unified Data Management (UDM) entity, the function of the PMN may be implemented by a Policy Control Function (PCF) entity, the function of the SMN may be implemented by a Session Management Function (SMF) entity, the function of the UPN may be implemented by a User Plane Function (UPF) entity, and the function of the MMN may be implemented by an access and mobility management function (AMF) entity.

The above entities included in the 5G network will be described below by taking the PS network as the 5G network as an example.

The UDM entity is responsible for storing information such as a user permanent identifier (SUPI), a credential (trusted identity), a security context (security context), subscription data, etc. of a subscribed user in the operator network. These information stored by the UDM entity can be used for authentication and authorization of the terminal device to access the operator network. The subscriber of the operator network may be specifically a user using a service provided by the operator network, for example, a user using a mobile phone core card of china telecommunications, or a user using a mobile phone core card of china mobile, and the like. The SUPI of the subscriber may be the number of the mobile phone core card. The credentials and security context of the subscriber may be a small file stored with an encryption key of the core card of the mobile phone or information related to encryption of the core card of the mobile phone, and used for authentication and/or authorization. The security context may be data (cookie) or token (token) stored on the user's local terminal (e.g., cell phone), etc. The subscription data of the subscriber may be a service associated with the mobile phone core card, such as a traffic package or a network using the mobile phone core card.

The PCF entity is configured to provide a policy of a Protocol Data Unit (PDU) session to the SMF network element. The policy may include a charging related policy, a quality of service (QoS) related policy, an authorization related policy, and the like.

The SMF entity is responsible for session-related functions such as session management (e.g., session establishment, modification, and release), selection and control of UPF network elements, Service and Session Continuity (SSC) mode selection, roaming, and the like.

The UPF entity provides the functions related to the user plane such as routing and forwarding of data between the terminal equipment and an external data network, packet detection, service usage reporting, QoS processing, legal monitoring, uplink packet detection, downlink data packet storage and the like.

The AMF entity is responsible for access control and mobility management of the terminal device accessing to the operator network, including functions such as mobility state management, user temporary identity assignment, user authentication and authorization, selection of a suitable SMF entity for the terminal device, and establishment of a relevant session.

It should be noted that: (1) the terminal device may access the PS network through a (radio) access network (R) AN device, which is referred to as AN device hereinafter and is not illustrated in fig. 1, 2a and 2b for a while. AN device may also be referred to as a base station or a network device. Currently, some examples of AN devices are: a new generation base station (gbodeb), a Transmission Reception Point (TRP), an evolved Node B (eNB), a Radio Network Controller (RNC), a Node B (NB), a Base Station Controller (BSC), a Base Transceiver Station (BTS), a home base station (e.g., a home evolved NodeB or home Node B, HNB), a Base Band Unit (BBU), or a wireless fidelity (Wi-Fi) Access Point (AP), etc. in the 5G communication system. In addition, in one network configuration, the network device may include a Centralized Unit (CU) node, or a Distributed Unit (DU) node, or a RAN device including a CU node and a DU node. Furthermore, the network device may be other means for providing wireless communication functionality for the terminal device, where possible.

(2) The functional entity related in the embodiment of the present application may also be referred to as a network element, which is not limited in the present application. For example, the AMF entity may also be referred to as an AMF network element, the SMF entity may also be referred to as an SMF network element, and so on. The names of the entities are not limited in this application, and those skilled in the art can replace the names of the network elements with other names to perform the same functions, all of which belong to the protection scope of this application.

(3) The network element or the functional entity may be a network element in a hardware device, a software function running on dedicated hardware, or a virtualization function instantiated on a platform (e.g., a cloud platform), which is not limited in this application.

(4) Cx, Mw, Rx, Gx, S5, S8, S11, S6a, N8, N10, N11 in FIGS. 2a and 2b are interface serial numbers. The meaning of these interface sequence numbers can be referred to as that defined in the 3GPP standard protocol, and is not limited herein.

(5) The terms "system" and "network" in the embodiments of the present application may be used interchangeably. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a alone, A and B together, and B alone, wherein A and B may be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. And, unless specifically stated otherwise, the embodiments of the present application refer to the ordinal numbers "first", "second", etc., for distinguishing between a plurality of objects, and do not limit the order, sequence, priority, or importance of the plurality of objects. For example, the first information and the second information are different information only for distinguishing them, and do not indicate a difference in priority, importance, or the like between the two information.

When the terminal device 1 needs to establish a connection with the terminal device 2 through the IMS, an invite (invite) message or a call request may be triggered; terminal device 1 may be referred to as a calling terminal device, and terminal device 2 may be referred to as a called terminal device. The called terminal device may be in a connected state, or may also be in an idle state or an inactive state.

Case 1: the called terminal equipment is in a connected state

Referring to fig. 3a, a schematic diagram of a service processing flow of the called terminal device is shown. Taking the network architecture illustrated in fig. 2b as an example, as shown in fig. 3a, the service processing flow of the called terminal device includes the following steps:

step 301, the P-CSCF entity receives an invite message from the calling party, where the invite message includes an identifier of the called terminal device.

In step 302, the P-CSCF entity sends an invite message to the UPF entity.

Step 303, after receiving the invite message from the P-CSCF entity, the UPF entity sends the invite message to the called terminal device if it is determined that the called terminal device is in a connected state.

In step 304, after receiving the invite message from the UPF entity, the called terminal device returns a response message (such as 183 message) to the P-CSCF entity to indicate that the called terminal device has received the invite message.

Step 305, after receiving the 183 message, the P-CSCF entity sends an authentication & authorization request (AAR) message to the PCF entity.

Step 306, the PCF entity sends a re-authentication-request (RAR) message to the SMF entity after receiving the AAR message from the P-CSCF entity.

In step 307, after receiving the RAR message from the PCF entity, the SMF entity returns a re-authentication-answer (RAA) message to the PCF entity.

Step 308, the PCF entity returns an Authentication Authorization Answer (AAA) message to the P-CSCF entity after receiving the RAA message from the SMF entity.

For example, the procedure illustrated in steps 305 to 308 refers to a procedure for establishing a voice bearer for the called terminal device based on the IMS session of the called terminal device, where the voice bearer may be a bearer with quality of service (QoS) class identifier (QCI) ═ 1, and is used for carrying voice service. When the AAA message received by the P-CSCF entity indicates that the voice bearer is successfully established, the P-CSCF entity can execute the subsequent flow so as to realize the voice call between the calling terminal equipment and the called terminal equipment.

Case 2: the called terminal equipment is in an idle state or an inactive state

Referring to fig. 3b, a schematic diagram of a service processing flow of the called terminal device is shown. Taking the network architecture illustrated in fig. 2b as an example, as shown in fig. 3b, the service processing flow of the called terminal device includes the following steps:

step 311, the P-CSCF entity receives an invite message from the calling party, where the invite message includes an identifier of the called terminal device.

In step 312, the P-CSCF entity sends an invite message to the UPF entity.

Step 313, after receiving the invite message from the P-CSCF entity, the UPF entity sends a downlink data report (downlink data report) message to the SMF to request to reestablish the IMS session if it is determined that the called terminal device is in an idle state or an inactive state.

Step 314, after receiving the downlink data report message, the SMF entity establishes an IMS session for the terminal device.

Step 315, the UPF entity sends invite message to the called terminal equipment through IMS session.

In step 316, the called terminal device returns 183 message to the P-CSCF entity after receiving the invite message from the UPF entity.

Step 317, after the P-CSCF entity receives the 183 message, it sends an authentication authorization AAR message to the PCF entity.

In step 318, the PCF entity sends a RAR message to the SMF entity after receiving the AAR message from the P-CSCF entity.

In step 319, after receiving the RAR message from the PCF entity, the SMF entity returns an RAA message to the PCF entity.

In step 3110, the PCF entity returns an AAA message to the P-CSCF entity after receiving the RAA message from the SMF entity.

Illustratively, after the AAA message received by the P-CSCF entity indicates that the voice bearer is successfully established, the P-CSCF entity may perform a subsequent procedure to implement the voice call between the calling terminal device and the called terminal device.

However, in the flows illustrated in fig. 3a and 3b, the IMS service may fail due to a failure scenario (e.g., a failure of a network entity or a network failure between two network entities that need to communicate) that causes a failure in the called flow process.

Several scenarios that lead to the failure of the called flow process are illustrated below:

in scenario 1, in step 302 of fig. 3a and step 312 of fig. 3b, if the UPF entity fails or is abnormal, or a network between the P-CSCF entity and the UPF entity fails, the called terminal device cannot receive the invite message, so that the P-CSCF entity does not receive a response from the called terminal device after timeout, and the called flow processing fails.

In scenario 2, in step 313 of fig. 3b, if the SMF entity fails or is abnormal, or the network between the UPF entity and the SMF entity fails, the called terminal device cannot receive the invite message, so that the P-CSCF entity does not receive a response from the called terminal device after timeout, and the called process fails to be processed.

Scenario 3, in step 305 of fig. 3a and step 317 of fig. 3b, if the P-CSCF entity senses that the PCF entity is faulty, no AAR message is sent; or the P-CSCF entity sends the AAR message, but the P-CSCF entity does not receive the response of the PCF entity after time out due to the failure of the PCF entity or the network failure between the P-CSCF entity and the PCF entity; or, the PCF entity does not already have the relevant information of the IMS session, which results in the failure of the called procedure processing.

Scenario 4, in step 306 of fig. 3a and step 318 of fig. 3b, if the PCF entity senses that the SMF entity fails, no RAR message is sent; or PCF entity sends RAR message to SMF entity, but PCF entity time out and does not receive SMF response due to SMF entity failure or network failure between SMF and PCF; or, the SMF entity does not have the information related to the IMS session, which results in the failure of the called procedure.

For some fault scenarios in the above described fault scenario, such as a failure of a PCF entity or a UPF entity, a possible solution is that, after the SMF entity senses the failure of the UPF entity or the PCF entity, the SMF entity triggers a deletion process of a related session, and requests the corresponding terminal device to reestablish the session, and selects a network node in a normal state for the session in the session reestablishing process. However, in order to avoid the impact on the network node of the existing network, a smoothing process is performed, for example, the SMF entity may divide the terminal devices that need to reestablish the session into a plurality of groups, reestablish the session of one group of terminal devices, then reestablish the session of another group of terminal devices, and so on until all the sessions are reestablished. With this method, it is possible to cause an interruption of the service of the called terminal device of more than 10 minutes.

It can be understood that the above described fault scenario may also occur in the calling processing flow, but since the calling processing flow is initiated by the calling terminal device, when the above fault occurs in the calling flow (for example, the SMF entity senses a fault of the UPF entity or the PCF entity), the SMF entity may select a new UPF entity or PCF entity for the terminal device in time, so as to recover the IMS service; in the called processing flow, the IMS service cannot be recovered in time by the above method.

Therefore, the embodiment of the application provides a method and a device for recovering an IMS service, which are used for recovering the IMS service of a terminal device in time and avoiding the influence on user experience caused by long interruption time of the IMS service.

Exemplarily, in the method for recovering an IMS service provided in the embodiment of the present application, taking the network architecture illustrated in fig. 2b as an example, if the UDM entity determines that an IMS session of the terminal device fails, and the IMS session is used for carrying the IMS service of the terminal device, the UDM entity sends first indication information to the AMF entity and/or the SMF entity, where the first indication information is used for indicating to recover the IMS service of the terminal device, and then the AMF entity and/or the SMF entity may reestablish the IMS session for the terminal device, so as to recover the IMS service of the terminal device. By adopting the scheme, the UDM entity can trigger the AMF entity and/or the SMF entity to reestablish the IMS session of the terminal equipment after determining that the IMS session of the terminal equipment fails, so that the IMS service of the terminal equipment is recovered in time.

The following describes related art features related to embodiments of the present application. It should be noted that these explanations are for the purpose of making the examples of the present application easier to understand, and should not be construed as limiting the scope of protection claimed in the present application.

(1) Status of a session

In this embodiment, a session may refer to a PDU session. The terminal device registers with the AMF entity in the PS network and then establishes a PDU session for IMS services through the SMF entity, which may be referred to as an IMS session.

Illustratively, the terminal device may be established with a plurality of PDU sessions, and the SMF entity corresponding to each PDU session may be different. Further, when a PDU session of the terminal device is successfully established, the AMF entity may store an identifier of the SMF entity serving the PDU session, and the SMF entity may store an identifier of the AMF entity serving the terminal device.

The PDU session can be in two stable states, active state or inactive state (inactive), the PDU session established successfully is in active state, and the PDU session released successfully is in inactive state, wherein the inactive state can also be called as deactivated state. In the embodiment of the present application, releasing (release) a session may also be understood as deleting (delete) a session, and the releasing session is described in the embodiment of the present application as an example.

(2) PDU session (or IMS session) establishment flow

Please refer to fig. 4a, which is a schematic diagram illustrating a PDU session establishment procedure according to an embodiment of the present application, where fig. 4a includes the following steps:

step 401: the terminal equipment sends a PDU session establishment request (PDU session establishment request) message to the SMF entity, and requests the SMF entity to establish the PDU session for the terminal equipment. Illustratively, the terminal device may transmit a PDU session setup request message to the SMF entity through the AN device and the AMF entity.

Step 402 a: after receiving a PDU session establishment request message sent by a terminal device, if it is determined that a PDU session can be established for the terminal device, an SMF entity sends a PDU session establishment accept (PDU session establishment accept) message to the terminal device, the terminal device receives the PDU session establishment accept message from the SMF entity, the establishment of the PDU session is completed, and at this time, the PDU session enters an active state. Illustratively, the SMF entity may receive the PDU session setup request message from the terminal device through the AN device and the AMF entity, and accordingly, the SMF entity may transmit the PDU session setup accept message to the terminal device through the AMF entity and the AN device.

Step 402 b: after receiving a PDU session establishment request message sent by a terminal device, if it is determined that a PDU session cannot be established for the terminal device, an SMF entity sends a PDU session establishment rejection (PDU session establishment reject) message to the terminal device, the terminal device receives the PDU session establishment rejection message from the SMF entity, the PDU session establishment fails, and at this time, the PDU session enters an inactive state. Illustratively, the SMF entity may send a PDU session setup reject message to the terminal device through the AMF entity and the AN device.

It should be noted that the step 402a and the step 402b are alternatively executed.

(3) PDU session (or IMS session) release flow

Referring to fig. 4b, a PDU session release flow diagram provided in this embodiment is shown in fig. 4b, where fig. 4b shows a PDU session release flow initiated by an SMF entity, and fig. 4b includes the following steps:

step 411: the SMF entity transmits a PDU session release command (PDU session release command) to the terminal device. Illustratively, the SMF entity may send the PDU session release command to the terminal device through the AMF entity as well as the AN device.

Step 412: and the terminal equipment sends a PDU session release complete message to the SMF entity. Illustratively, the terminal device may send a PDU session release complete message to the SMF entity through the AN device and the AMF entity.

In fig. 4b, the SMF entity may directly send a PDU session release command to the terminal device to initiate a PDU session release process, and after the terminal device replies a PDU session release completion message to the SMF entity, the release of the PDU session is completed, and at this time, the PDU session enters an inactive state or a deactivated state.

(4) Synchronizing states of PDU sessions

Illustratively, the maximum number of PDU sessions that can be simultaneously established by a terminal device in a Public Land Mobile Network (PLMN) may be determined by the minimum of "protocol-defined maximum (16)", "maximum PDU sessions supported by the PLMN", and "upper limit implemented by the terminal device". For example, if the "maximum value of the protocol definition" is 16, the "maximum value of the number of PDU sessions supported by the PLMN" is 12, and the "upper limit implemented by the terminal device" is 14, the maximum value of the number of PDU sessions that can be simultaneously established by the terminal device in the PLMN is 12. The PLMN may be understood as an operator network. The "maximum number of PDU sessions supported by a PLMN" may be understood as the maximum number of PDU sessions that the PLMN can support to establish for the terminal device; the "upper limit implemented by the terminal device" may be understood as a software and/or hardware configuration for the terminal device such that the terminal device is able to support the maximum value of the established PDU session.

In a possible example, if the terminal device 1 determines that the number of currently established PDU sessions does not exceed "the maximum value of protocol definition (16)", nor does it exceed "the upper limit implemented by the terminal device", at this time, the terminal device 1 may continue to initiate a PDU session establishment request by using the method shown in fig. 4a, and when the AMF entity receives the PDU session establishment request sent by the terminal device 1, if the number of PDU sessions established by the terminal device 1 reaches the maximum value of the number of PDU sessions supported by the PLMN, the AMF entity may reject the PDU session establishment request, and reply a message carrying a cause value of #65 to the terminal device 1, where the cause value of #65 indicates that the number of established PDU sessions has reached the maximum value (maximum number of PDU sessions retrieved), and after the terminal device 1 receives the message carrying the cause value of #65 from the AMF entity, the number of established PDU sessions at this time is considered to be "the maximum value of session supported by the PLMN", and the maximum value of the PDU conversation quantity which can be simultaneously established by the terminal equipment in one PLMN can be determined to be the conversation maximum value supported by the PLMN according to the protocol specification.

To ensure that the PDU session established between the terminal device and the network does not exceed the maximum value specified by the protocol, the terminal device and the network need to maintain the status of the PDU session and the number of established PDU sessions individually. Illustratively, after the terminal device successfully establishes the PDU session, the terminal device sets the status of the PDU session to an active status, and adds one to the number of the established PDU sessions maintained, and accordingly, a core network element (e.g., an AMF entity) sets the status of the PDU session to an active status, and adds one to the number of the established PDU sessions maintained by the terminal device; on the contrary, when the terminal device releases the PDU session successfully, the terminal device sets the status of the PDU session to an inactive state and reduces the number of the established PDU sessions maintained by the terminal device by one, and correspondingly, the core network element (e.g., the AMF entity) sets the status of the PDU session to an inactive state and reduces the number of the established PDU sessions maintained by the terminal device by one. The network maintains the number of established PDU sessions, which may be understood as that the AMF entity maintains the number of active PDU sessions of each terminal device accessing the core network through the AMF entity.

Illustratively, a PDU session status Information Element (IE) may be used to synchronize the PDU session status of the terminal device with the network. As shown in fig. 5, a format diagram of a PDU session status information element is shown, where a value (0/1) of each bit (bit) included in octet3 and octet4 in the IE represents a status of one PDU session, that is, each bit may correspond to one PDU session, specifically, when the value of the bit is 0, it indicates that the PDU session corresponding to the bit is in an inactive state, and conversely, when the value of the bit is 1, it indicates that the PDU session corresponding to the bit is in an active state. For example, the terminal device and the network may carry the PDU session state information element through three flows of SERVICE REQUEST (SERVICE REQUEST), REGISTRATION (REGISTRATION), or NOTIFICATION (NOTIFICATION), so as to achieve the purpose of PDU session state synchronization.

Based on the above description of the relevant features, the following describes in detail the embodiments of the present application with reference to the first embodiment and the second embodiment.

Example one

In the first embodiment, a possible implementation flow will be described by taking an example that the method in the embodiment of the present application is applied to the network architecture illustrated in fig. 2 b.

Referring to fig. 6, a flowchart corresponding to a method for recovering an IMS service according to an embodiment of the present invention is shown in fig. 6, including:

step 601, the AMF entity sends first information to the UDM entity, where the first information is used to request to Subscribe to an IMS Session Failure Event (subscription IMS Session Failure Event) of the terminal device.

Illustratively, when the terminal device registers with the AMF entity, the AMF entity may send a message 1 to the UDM entity, where the message 1 includes first information, and the first information may also be used to notify the UDM entity of a target address of the AMF entity when the IMS session failure event notification is performed. For example, the specific embodiment of the message 1 may be a user context management Registration Request (numdm _ UECM _ Registration Request), and the first information is an imssensofaturebackuri parameter newly added in Amf3 gpppaccessionregistration and AmfNon3 gpaccessionregistration cells of the user context management Registration Request.

Step 602, the SMF entity sends second information to the UDM entity, where the second information is used to request to subscribe to an IMS session failure event of the terminal device.

Exemplarily, when the terminal device requests the SMF entity to establish the IMS session, the SMF entity may send a message 2 to the UDM, where the message 2 includes second information, and the second information may also be used to notify the UDM entity of a target address of the SMF entity when the IMS session failure event notification is performed. For example, the message 2 is embodied as a user context management Registration Request (numm _ UECM _ Registration Request), and the second information is an imsessionfailure CallbackUri parameter newly added in an SmfRegistration cell of the user context management Registration Request.

Step 603, the S-CSCF entity sends second indication information to the UDM entity, where the second indication information is used to indicate that the IMS session of the terminal device fails.

Exemplarily, in the flows illustrated in fig. 3a and 3b, when the failure scenario described above occurs, the P-CSCF entity may return a failure response message to the S-CSCF entity indicating that the IMS session of the terminal device fails. The specific embodiment of the failure response message may be a Session Initiation Protocol (SIP) 604, which means that the server verifies the user information in the request, and where the user information Does Not exist (doss Not Exists from Anywhere). Furthermore, after receiving the failure response message sent by the P-CSCF entity, the S-CSCF entity may send a message 3 to the UDM, where the message 3 includes the second indication information. For example, the specific embodiment of the message 3 may be a Registration Notification Request or a de-Registration Notification Request (Registration/de-Registration Notification Request), and the second indication information may be a Subscribe-IMS-Session-Failure parameter newly added in a SAR-Flags cell of the Registration Notification Request or the de-Registration Notification Request.

Step 604, the UDM entity receives the second indication information, and further determines that the IMS session of the terminal device fails.

Step 605, the UDM entity sends first indication information to the SMF entity, where the first indication information is used to indicate that the IMS session of the terminal device fails.

Exemplarily, the UDM entity may send the first indication information to the SMF entity if it is determined that the SMF entity is subscribed to the IMS session failure event. For example, the UDM entity may send a message 4 to the SMF entity, where the message 4 includes first indication information, and the first indication information may include an identifier of the terminal device, or other possible information, which is not limited specifically. For example, the message 4 may be an added message in the form of a user context management IMS session failure Request (numm _ UECM _ IMS failure Request).

Step 606, the UDM entity determines whether the SMF entity successfully recovers the IMS session of the terminal device, and if so, the flow is ended; otherwise, step 607 is executed.

For example, after the UDM entity sends the first indication information to the SMF entity, if the response message of the SMF entity is not received within the preset time period, it may be determined that the SMF entity has not successfully recovered the IMS session of the terminal device, if the response message of the SMF is received within the preset time period, when a cause value (cause) carried in the response message indicates that the SMF entity has successfully recovered the IMS session of the terminal device, it may be determined that the SMF entity has successfully recovered the IMS session of the terminal device, and when the cause value carried in the response message indicates that the SMF entity has not successfully recovered the IMS session of the terminal device, it may be determined that the SMF entity has not successfully recovered the IMS session of the terminal device.

There may be various ways for the SMF entity to successfully recover the IMS session of the terminal device, for example, the SMF entity executes an IMS session release procedure (see fig. 4 b), and the terminal device may reestablish the IMS session (see fig. 4 a). There may be various reasons why the SMF has not successfully recovered the IMS session of the terminal device, such as information about the IMS session of the terminal device already on the SMF entity.

Illustratively, the Response message sent by the SMF entity to the UDM entity may be a new message, and the embodiment may be a user context management IMS session failure Response (numm _ UECM _ IMS failure Response), where the Response message may carry a cause cell.

It should be noted that, in other possible embodiments, if the UDM entity determines that the SMF fails, the first indication information may not be sent to the SMF any more, and it is determined that the SMF entity does not successfully recover the IMS session of the terminal device.

In step 607, the UDM entity sends the first indication information to the AMF entity.

Illustratively, the UDM entity may send the first indication information to the AMF entity if it is determined that the AMF entity is subscribed to the IMS session failure event. For example, the UDM entity may send a message 5 to the AMF entity, the message 5 including the first indication information. The message 5 may be a newly added message, and the embodiment form may be a user context management IMS session failure Request (numm _ UECM _ IMS failure Request).

In step 608, the AMF entity sends a response message to the UDM entity.

Illustratively, the Response message sent by the AMF entity to the UDM entity may be a new message, and the embodiment may be in the form of a user context management IMS session failure Response (numm _ UECM _ IMS failure Response).

Step 609, the AMF entity sends third indication information to the terminal device, where the third indication information is used to indicate the terminal device to reestablish the IMS session.

Exemplarily, the AMF entity may send a message 6 to the terminal device, where the message 6 includes third indication information, and the third indication information may include state information of the IMS session, where the state information of the IMS session is used to indicate that the IMS session is in an inactive state. The message 6 may be embodied as a Configuration Update Command (Configuration Update Command), and a PDU session status cell may be newly added in the Configuration Update Command, where the PDU session status cell is used to carry status information of an IMS session.

And step 610, the terminal device receives the third indication information and reestablishes the IMS session of the terminal device.

For example, after receiving the state information of the IMS session, the terminal device determines that the state (i.e., the activated state) of the IMS session stored in the terminal device is inconsistent with the state (i.e., the deactivated state) of the IMS session indicated by the third indication information, and may reestablish the IMS session of the terminal device (see fig. 4 a).

In the above-described procedure (for convenience of description, the implementation procedure is referred to as a first implementation procedure), both the AMF entity and the SMF entity subscribe to the UDM entity for an IMS session failure event of the terminal device, and after the subsequent UDM entity determines that the IMS session of the terminal device fails, the subsequent UDM entity may first send first indication information to the SMF entity, and if the SMF entity does not successfully recover the IMS session of the terminal device, the UDM entity may send the first indication information to the AMF entity, so that the AMF entity recovers the IMS session of the terminal device; if the SMF entity successfully recovers the IMS session of the terminal device, the UDM entity may not send the first indication information to the AMF entity any more, so as to save signaling overhead and transmission resource overhead.

It should be noted that the above-mentioned flow is only one possible implementation flow, and in other embodiments, there may be other implementation flows, such as the second implementation flow to the fifth implementation flow.

The second implementation process: the AMF entity and the SMF entity subscribe an IMS session failure event of the terminal equipment to the UDM entity, the subsequent UDM entity can firstly send first indication information to the AMF entity after determining that the IMS session of the terminal equipment fails, and if the AMF entity does not successfully recover the IMS session of the terminal equipment, the UDM entity can send the first indication information to the SMF entity so that the SMF entity recovers the IMS session of the terminal equipment; if the AMF entity successfully recovers the IMS session of the terminal device, the UDM entity may no longer send the first indication information to the SMF entity.

The third implementation process: the AMF entity and the SMF entity both subscribe to an IMS session failure event of the terminal device to the UDM entity, and after determining that the IMS session of the terminal device fails, the subsequent UDM entity may send first indication information to the AMF entity and the SMF entity, where the sequence of sending the first indication information by the UDM entity to the AMF entity and the SMF entity may not be limited, for example, the UDM entity may send the first indication information to the AMF entity and the SMF entity at the same time. Accordingly, after receiving the first indication information, the AMF entity and the SMF entity may reestablish the IMS session for the terminal device.

The fourth implementation process: the AMF entity subscribes an IMS session failure event of the terminal device to the UDM entity (the SMF entity is not subscribed), and after determining that the IMS session of the terminal device fails, the subsequent UDM entity may send first indication information to the AMF entity. Accordingly, after receiving the first indication information, the AMF entity may reestablish the IMS session for the terminal device.

The fifth implementation process: the SMF entity subscribes to an IMS session failure event of the terminal device from the UDM entity (the AMF entity is not subscribed), and after determining that the IMS session of the terminal device fails, the subsequent UDM entity may send first indication information to the SMF entity. Accordingly, after receiving the first indication information, the SMF entity may reestablish the IMS session for the terminal device.

In addition, in the implementation procedure described above, the AMF entity re-establishes the IMS session for the terminal device after receiving the first indication information sent by the UDM entity. In this embodiment, the AMF entity may also reestablish the IMS session for the terminal device after sensing the SMF entity failure.

For example, terminal device 1, terminal device 2, and terminal device 3 all establish a PDU session on the SMF entity, which is PDU session 1, PDU session 2, and PDU session 3, respectively. Because the AMF entity may store the identifier of the SMF entity serving the PDU session of the terminal device, when the AMF entity senses that the SMF entity fails, it is known that PDU session 1, PDU session 2, and PDU session 3 need to be reestablished, and then PDU session 1, PDU session 2, and PDU session 3 may be reestablished for terminal device 1, terminal device 2, and terminal device 3, respectively, in the manner described in step 609.

Example two

In the second embodiment, a possible implementation flow will be described by taking an example that the method in the embodiment of the present application is applied to the network architecture illustrated in fig. 2 a.

Referring to fig. 7, a flowchart corresponding to a method for recovering an IMS service according to a second embodiment of the present application is shown in fig. 7, where the method includes:

step 701, the MME sends first information to the HSS, where the first information is used to request to subscribe to an IMS session failure event of the terminal device.

Illustratively, when the terminal device registers with the MME, the MME may send message 1 to the HSS, message 1 including the first information. For example, the specific embodiment of the message 1 may be an Update Location Request (Update Location Request), and the first information is a describe-IMS-Session-Failure parameter newly added in an ULR-Flags cell of the Update Location Request.

In step 702, the PGW-C entity sends second information to the HSS, where the second information is used to request to subscribe to an IMS session failure event of the terminal device.

Exemplarily, when the terminal device requests the PGW-C entity to establish the IMS session, the PGW-C entity may send a message 2 to the HSS, where the message 2 includes the second information. For example, the message 2 may be a newly added message, the embodiment form may be a PGW Update Location Request (PGW Update Location Request), and the second information may be a Subscribe-IMS-Session-Failure parameter carried in the PGW Update Location Request.

In step 703, the S-CSCF entity sends second indication information to the HSS, where the second indication information is used to indicate that the IMS session of the terminal device fails.

Exemplarily, in the flows illustrated in fig. 3a and 3b, when the failure scenario described above occurs, the P-CSCF entity may return a failure response message to the S-CSCF entity indicating that the IMS session of the terminal device fails. Furthermore, after receiving the Failure response message sent by the P-CSCF entity, the S-CSCF entity may send a message 3 to the HSS, where the message 3 includes second indication information, the specific embodiment of the message 3 may be a registration notification request or a de-registration notification request, and the second indication information may be a Subscribe-IMS-Session-Failure parameter newly added in an SAR-Flags cell of the registration notification request or the de-registration notification request.

Step 704, the HSS receives the second indication information, and further determines that the IMS session of the terminal device fails.

Step 705, the HSS sends first indication information to the PGW-C entity, where the first indication information is used to indicate that the IMS session of the terminal device fails.

For example, if determining that the PGW-C entity is subscribed to the IMS session failure event, the HSS may send the first indication information to the PGW-C entity. For example, the HSS may send a message 4 to the PGW-C entity, where the message 4 includes the first indication information. The message 4 may be an added message, for example, a PGW inserts a user Data Request (PGW Insert Subscriber Data Request), and the first indication information may be an IMS-Session-Failure parameter added in an IDR Flags cell of the PGW inserting the user Data Request.

Step 706, the HSS determines whether the PGW-C entity successfully recovers the IMS session of the terminal device, and if so, ends the procedure; otherwise, step 707 is executed.

For example, after the HSS sends the first indication information to the PGW-C entity, if a response message of the PGW-C entity is not received within a preset time period, it may be determined that the PGW-C entity does not successfully recover the IMS session of the terminal device, if the response message of the PGW-C entity is received within the preset time period, when a cause value (cause) carried in the response message indicates that the PGW-C entity successfully recovers the IMS session of the terminal device, it may be determined that the PGW-C entity successfully recovers the IMS session of the terminal device, and when the cause value carried in the response message indicates that the PGW-C entity does not successfully recover the IMS session of the terminal device, it may be determined that the PGW-C entity does not successfully recover the IMS session of the terminal device.

The PGW-C entity may successfully recover the IMS session of the terminal device in a variety of ways, for example, the PGW-C entity executes an IMS session release procedure, and the terminal device may reestablish the IMS session. There may be various reasons why the PGW-C entity fails to recover the IMS session of the terminal device, such as that the PGW-C entity does not have information about the IMS session of the terminal device.

For example, the response message sent by the PGW-C entity to the HSS may be a newly added message, and the embodiment form may be that a user Data response (PGW Insert Subscriber Data Answer) is inserted into the PGW, and the cause cell may be carried in the response message.

It should be noted that, in other possible embodiments, if the HSS determines that the PGW-C entity fails, the HSS may not send the first indication information to the PGW-C entity any more, and determines that the PGW-C entity does not successfully recover the IMS session of the terminal device.

In step 707, the HSS transmits the first indication information to the MME.

For example, the HSS may send the first indication information to the MME if it determines that the MME is subscribed to the IMS session failure event. For example, the HSS may send message 5 to the MME, where the first indication information is included in message 5. The message 5 may be a new message, such as an Insert Subscriber Data Request (Insert Subscriber Data Request), and the first indication information may be an IMS-Session-Failure parameter newly added in an IDR Flags cell into which the Subscriber Data Request is inserted.

In step 708, the MME sends a response message to the HSS.

Illustratively, the response message sent by the MME to the HSS may be a new message in the form of an Insert Subscriber Data response (Insert Subscriber Data Answer).

Step 709, the MME sends third indication information to the terminal device, where the third indication information is used to indicate the terminal device to reestablish the IMS session.

Exemplarily, the MME may send a message 6 to the terminal device, where the message 6 includes the third indication information. The message 6 may be a deactivated Evolved Packet System (EPS) Bearer Context Request (deactivated EPS Bearer Context Request), and an ESM cause cell value for deactivating the EPS Bearer Context Request is #39, which indicates that deactivation is Requested (deactivation Requested).

And step 710, the terminal device receives the third indication information and reestablishes the IMS session of the terminal device.

In the embodiment of the present application, by using the solutions in the first embodiment and the second embodiment, after determining that the IMS session of the terminal device fails, the SDMN may trigger the MMN and/or the SMN to reestablish the IMS session of the terminal device, so as to recover the IMS service of the terminal device in time, and effectively reduce the time delay for recovering the IMS service.

It should be noted that: (1) since the second embodiment is applicable to the system architecture illustrated in fig. 2a and the first embodiment is applicable to the system architecture illustrated in fig. 2b, names of network entities or names of messages communicated between different network entities in the second embodiment and the first embodiment may be different, and the two may be referred to each other except for the difference. For example, in the second embodiment, the second to fourth implementation flows described in the first embodiment may also be adopted.

(2) The step numbers of the flowcharts (such as fig. 6 and 7) described in the embodiment of the present application are only an example of an execution flow, and do not limit the execution sequence of the steps, and there is no strict execution sequence between the steps that have no time sequence dependency relationship with each other in the embodiment of the present application.

The above-mentioned scheme provided by the embodiment of the present application is introduced mainly from the perspective of interaction between a network device and a terminal device. It is understood that, in order to implement the above functions, the network device or the terminal device may include a corresponding hardware structure and/or software module for performing each function. Those of skill in the art will readily appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as hardware or combinations of hardware and computer software. Whether a function is performed as hardware or computer software drives hardware depends upon the particular application and design constraints imposed on the solution. 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.

In the embodiment of the present application, the terminal device and the network device may be divided into the functional units according to the above method examples, for example, each functional unit may be divided corresponding to each function, or two or more functions may be integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

In case of integrated units, fig. 8 shows a possible exemplary block diagram of the apparatus involved in the embodiments of the present application. As shown in fig. 8, the apparatus 800 may include: a processing unit 802 and a communication unit 803. The processing unit 802 is used for controlling and managing the operation of the apparatus 800. The communication unit 803 is used to support the communication of the apparatus 800 with other devices. Optionally, the communication unit 803, also referred to as a transceiving unit, may include a receiving unit and/or a transmitting unit for performing receiving and transmitting operations, respectively. The apparatus 800 may further comprise a storage unit 801 for storing program codes and/or data of the apparatus 800.

The apparatus 800 may be an SDMN (such as the UDM entity in the first embodiment or the HSS in the second embodiment) or a chip disposed in the SDMN. The processing element 802 may enable the apparatus 800 to perform the actions of the SDMN in the method examples above. Alternatively, the processing unit 802 mainly performs internal actions of SDMN in the method example, and the communication unit 803 may support communication between the apparatus 800 and other apparatuses. For example, the processing unit 802 is configured to perform step 605 in fig. 6 or perform step 705 in fig. 7; the communication unit 803 may be used to perform step 604, step 607, step 608 of fig. 6, or to perform steps 704, step 707, step 708 of fig. 7 as well.

In one embodiment, the processing unit 802 is configured to: determining that an IMS session of the terminal equipment fails, wherein the IMS session is used for bearing an IMS service of the terminal equipment; the communication unit 803 is configured to: and sending first indication information to the MMN and/or the SMN, wherein the first indication information is used for indicating the IMS session failure of the terminal equipment.

In one possible design, the communication unit 803 is configured to: and receiving second indication information from a service call state control function (S-CSCF) entity, wherein the second indication information is used for indicating the IMS session failure of the terminal equipment.

In one possible design, the communication unit 803 is configured to: and receiving first information sent by the MMN, wherein the first information is used for requesting an IMS session failure event of the terminal equipment.

In one possible design, the communication unit 803 is configured to: and receiving second information from the SMN, wherein the second information is used for requesting the IMS session failure event of the subscribing terminal equipment.

The apparatus 800 may be an MMN (such as the AMF entity in the first embodiment or the MME in the second embodiment) or a chip disposed in the MMN. The processing unit 802 may enable the apparatus 800 to perform the actions of the MMN in the above method examples. Alternatively, the processing unit 802 mainly performs internal actions of the MMN in the method example, and the communication unit 803 may support communication between the apparatus 800 and other apparatuses. For example, the communication unit 803 may be configured to perform step 601, step 609 in fig. 6 or perform step 701, step 709 in fig. 7.

In one embodiment, the processing unit 802 is configured to: determining that an IMS session of the terminal equipment fails, wherein the IMS session is used for bearing an IMS service of the terminal equipment; and reestablishing the IMS session for the terminal equipment.

In one possible design, the communication unit 803 is configured to: and sending first information to the SDMN, wherein the first information is used for requesting the IMS session failure event of the subscription terminal equipment.

In one possible design, the communication unit 803 is further configured to: and sending third indication information to the terminal equipment, wherein the third indication information is used for indicating the terminal equipment to reestablish the IMS session.

The apparatus 800 may be an SMN (such as the SMF entity in the first embodiment or the PGW-C in the second embodiment) or a chip disposed in the SMN. The processing unit 802 may enable the apparatus 800 to perform the actions of the SMN in the above method examples. Alternatively, the processing unit 802 mainly performs internal actions of the SMN in the method example, and the communication unit 803 may support communication between the apparatus 800 and other apparatuses. For example, the communication unit 803 may be used to perform step 602 in fig. 6 or step 702 in fig. 7.

In one embodiment, the communication unit 803 is configured to: receiving first indication information from the SDMN, wherein the first indication information is used for indicating the IMS session failure of the terminal equipment, and the IMS session is used for bearing the IMS service of the terminal equipment; processing unit 802 is configured to re-establish an IMS session for the terminal device.

In one possible design, the communication unit 803 is further configured to: and sending second information to the SDMN, wherein the second information is used for requesting the IMS session failure event of the subscription terminal equipment.

The apparatus 800 may be a terminal device or a chip provided in the terminal device. The processing unit 802 may enable the apparatus 800 to perform the actions of the terminal device in the above method examples. Alternatively, the processing unit 802 mainly performs internal actions of the terminal device in the method example, and the communication unit 803 may support communication between the apparatus 800 and other apparatuses. For example, the processing unit 802 is configured to perform step 610 in fig. 6 or perform step 710 in fig. 7.

In one embodiment, the communication unit 803 is configured to: receiving third indication information from the MMN, wherein the third indication information is used for indicating the terminal equipment to reestablish an IMS session, and the IMS session is used for bearing an IMS service of the terminal equipment; the processing unit 802 is configured to reestablish the IMS session according to the third indication information.

In one possible design, the communication unit 803 is further configured to: and receiving a configuration update command from the MMN, wherein the configuration update command comprises third indication information.

It should be understood that the division of the units in the above apparatus is only a division of logical functions, and the actual implementation may be wholly or partially integrated into one physical entity, or may be physically separated. And the units in the device can be realized in the form of software called by the processing element; or may be implemented entirely in hardware; part of the units can also be realized in the form of software called by a processing element, and part of the units can be realized in the form of hardware. For example, each unit may be a processing element separately set up, or may be implemented by being integrated into a chip of the apparatus, or may be stored in a memory in the form of a program, and a function of the unit may be called and executed by a processing element of the apparatus. In addition, all or part of the units can be integrated together or can be independently realized. The processing element described herein may in turn be a processor, which may be an integrated circuit having signal processing capabilities. In the implementation process, the steps of the method or the units above may be implemented by integrated logic circuits of hardware in a processor element or in a form called by software through the processor element.

In one example, the units in any of the above apparatuses may be one or more integrated circuits configured to implement the above methods, such as: one or more Application Specific Integrated Circuits (ASICs), or one or more microprocessors (DSPs), or one or more Field Programmable Gate Arrays (FPGAs), or a combination of at least two of these Integrated Circuit formats. For another example, when a unit in a device may be implemented in the form of a processing element scheduler, the processing element may be a processor, such as a Central Processing Unit (CPU), or other processor capable of invoking a program. As another example, these units may be integrated together and implemented in the form of a system-on-a-chip (SOC).

The above unit for receiving is an interface circuit of the apparatus for receiving signals from other apparatuses. For example, when the device is implemented in the form of a chip, the receiving unit is an interface circuit for the chip to receive signals from other chips or devices. The above unit for transmitting is an interface circuit of the apparatus for transmitting a signal to other apparatuses. For example, when the device is implemented in the form of a chip, the transmitting unit is an interface circuit for the chip to transmit signals to other chips or devices.

Referring to fig. 9, a schematic diagram of an apparatus for recovering an IMS service according to an embodiment of the present application is shown, where the apparatus 900 may be an SDMN, an MMN, an SMN, or a terminal device in the foregoing embodiment. The apparatus 900 includes: a processor 902, a communication interface 903, and a memory 901. Optionally, the apparatus 900 may also include a communication line 904. Wherein the communication interface 903, the processor 902, and the memory 901 may be connected to each other through a communication line 904; the communication line 904 may be a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, or the like. The communication lines 904 may be divided into address buses, data buses, control buses, and the like. For ease of illustration, only one thick line is shown in FIG. 9, but this does not indicate only one bus or one type of bus.

The processor 902 may be a CPU, microprocessor, ASIC, or one or more integrated circuits configured to control the execution of programs in accordance with the teachings of the present application. The functionality of the processor 902 may be the same as the processing unit described in fig. 8.

The communication interface 903 may be any device, such as a transceiver, for communicating with other devices or communication networks, such as an ethernet, a Radio Access Network (RAN), a Wireless Local Area Network (WLAN), a wired access network, and the like. The function of the communication interface 903 may be the same as that of the communication unit described in fig. 8.

The memory 901 may be, but is not limited to, a ROM or other type of static storage device that can store static information and instructions, a RAM or other type of dynamic storage device that can store information and instructions, an electrically erasable programmable read-only memory (EEPROM), a compact disk read-only memory (CD-ROM) or other optical disk storage, optical disk storage (including compact disk, laser disk, optical disk, digital versatile disk, blu-ray disk, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. The memory may be separate and coupled to the processor via a communication line 904. The memory may also be integrated with the processor. The memory 901 may function the same as the memory unit described in fig. 8.

The memory 901 is used for storing computer-executable instructions for executing the scheme of the present application, and is controlled by the processor 902 to execute. The processor 902 is configured to execute the computer executable instructions stored in the memory 901, so as to implement the processing method of the session provided by the above-mentioned embodiment of the present application.

Optionally, the computer-executable instructions in the embodiments of the present application may also be referred to as application program codes, which are not specifically limited in the embodiments of the present application.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

Claims

1. A method of restoring network protocol multimedia subsystem, IMS, services, the method comprising:

receiving information for requesting an IMS session failure event of a subscriber terminal device from a session management network node;

determining that an IMS session of the terminal equipment fails, wherein the IMS session is used for bearing an IMS service of the terminal equipment;

and sending first indication information to a session management network node, wherein the first indication information is used for indicating the IMS session failure of the terminal equipment.

2. The method of claim 1, wherein the information requesting for an IMS session failure event of the subscribing terminal device is an ImsSessionFailure CallbackUri parameter.

3. The method according to claim 1 or 2, the method being performed by a user data management network node.

4. The method according to any of claims 1 to 3, the user data management network node being a unified data management, UDM, entity.

5. The method of claim 4, the session management network node being a session management function, SMF, entity.

6. The method according to any of claims 1 to 3, the subscriber data management network node being a unified data management home subscriber server, HSS.

7. The method of claim 6, the session management network nodes being a packet data network gateway control plane function, PGW-C, entity and a serving gateway control plane function, SGW-C, entity.

8. The method of any of claims 1 to 7, determining that the IMS session of the terminal device failed, comprising:

and receiving indication information from a service call state control function entity, wherein the indication information is used for indicating the IMS session failure of the terminal equipment.

9. The method of any of claims 1-8, further comprising:

and if the session management network node is determined not to successfully recover the IMS session of the terminal equipment, sending the first indication information to the mobile management network node.

10. The method of claim 9, wherein determining that the session management network node failed to recover the IMS session for the terminal device comprises:

receiving no response message of the session management network node within a preset time period; or,

and receiving a response message from the session management network node, wherein the response message carries a reason value for unsuccessfully recovering the IMS session of the terminal equipment.

11. The method according to claim 7 or 8, characterized in that the method further comprises:

and receiving information which is sent by the mobile management network node and requests to subscribe the IMS session failure event of the terminal equipment.

12. A method for recovering IMS services, the method comprising:

sending information for requesting an IMS session failure event of a subscription terminal device to a user data management network;

receiving first indication information from the user data management network, wherein the first indication information is used for indicating IMS session failure of the terminal equipment;

and reestablishing the IMS session for the terminal equipment.

13. The method of claim 12, wherein the information requesting for an IMS session failure event of the subscribing terminal device is an ImsSessionFailure callbacri parameter.

14. The method according to claim 12 or 13, the method being performed by a session management network node.

15. The method according to any of claims 12 to 14, the session management network node being a session management function, SMF, entity.

16. The method according to claim 15, the user data management network node being a unified data management, UDM, entity.

17. The method according to any of claims 12 to 14, the session management network nodes being a packet data network gateway control plane function, PGW-C, entity and a serving gateway control plane function, SGW-C, entity.

18. The method of claim 17, the subscriber data management network node being a unified data management home subscriber server, HSS.

19. The method of any of claims 12 to 18, re-establishing the IMS session for the terminal device, comprising:

and sending indication information for indicating the terminal equipment to reestablish the IMS session to the terminal equipment.

20. The method of claim 19, wherein the indication information for instructing the terminal device to reestablish the IMS session comprises state information of the IMS session, and the state information of the IMS session is used to indicate that the state of the IMS session is an inactive state.

21. The method according to claim 19 or 20, wherein sending, to the terminal device, indication information for instructing the terminal device to reestablish the IMS session comprises:

sending a configuration update command to the terminal device, where the configuration update command includes the indication information for indicating the terminal device to reestablish the IMS session.

22. An apparatus for restoring IMS services, comprising:

a communication interface for communicating with other devices;

a memory for storing computer programs and data;

a processor for running the computer program in the memory, reading the computer program in the memory, and executing the method according to any one of claims 1-11 through the communication interface.

23. An apparatus for restoring IMS services, comprising:

a communication interface for communicating with other devices;

a memory for storing computer programs and data;

a processor for executing the computer program in the memory, reading the computer program in the memory, and executing the method according to any one of claims 12-21 via the communication interface.

24. A computer storage medium, characterized in that a computer program is stored in the computer storage medium, which computer program, when executed by a computer, causes the computer to carry out the method according to any one of claims 1-21.