Call recovery method and device, storage medium and program product

Abstract

The invention provides a call recovery method and device, a storage medium and a program product, relates to the technical field of communication, and is used for improving the success rate of a call. The method comprises: after a policy control network element creates a first session in response to a first session creation request of a proxy call session control network element (P-CSCF), determining whether a core network element associated with the first session has a fault; and under the condition that a core network element associated with the first session fails, the policy control network element sends a first request message to the P-CSCF, the first request message being used for requesting to terminate the first session and triggering a failure recovery process of the P-CSCF.

Description

Technical Field

[0001] The present disclosure relates to the field of communication technologies, and in particular, to a call recovery method, apparatus, storage medium, and program product. Background Art

[0002] Since the fourth-generation mobile communication technology (4G), the voice calls and multimedia services of wireless communication systems have gradually migrated from the traditional circuit-switched domain to the IP multimedia subsystem (IMS) domain. This migration enables both voice and data services to be transmitted through the packet switched domain (PS domain, data domain), thus greatly improving network efficiency and flexibility.

[0003] After a user attaches or registers to a mobile communication network, the system will establish a packet data network (PDN) connection or protocol data unit (PDU) session specifically for IMS services. These connections and sessions are the basis for subsequent IMS services (such as IMS voice termination and origination). It can be seen that a successful IMS voice call involves a wireless communication network and an IMS system, and there are many types of network elements involved. With the rapid increase in the number of users and the continuous expansion of the network, the reliability of voice calls faces severe challenges. Therefore, considering various fault scenarios, how to ensure the rapid recovery of voice calls and improve the call success rate has become an urgent problem to be solved. Summary of the Invention

[0004] Embodiments of the present disclosure provide a call recovery method, apparatus, storage medium, and program product for improving the call success rate. The technical solutions provided by the embodiments of the present disclosure are as follows:

[0005] On the one hand, a call recovery method is provided, which is applied to a policy control network element. The method includes:

[0006] After the policy control network element creates a first session in response to a first session creation request from a proxy call session control function (P-CSCF), determine whether a core network element associated with the first session has a fault;

[0007] In the case where a core network element associated with the first session has a fault, send a first request message to the P-CSCF. The first request message is used to request termination of the first session and trigger a fault recovery process of the P-CSCF.

[0008] On the other hand, a call recovery device is provided, which is applied to a policy control network element. The device includes:

[0009] A processing module, configured to determine whether a core network element associated with a first session fails after the policy control network element creates the first session in response to a first session creation request of a proxy call session control network element (P-CSCF);

[0010] A communication module, configured to send a first request message to the P-CSCF when the core network element associated with the first session fails. The first request message is used to request to terminate the first session and trigger a fault recovery process of the P-CSCF.

[0011] In another aspect, a communication device is provided, including: a memory and a processor; the memory and the processor are coupled; the memory is used to store computer program instructions executable by the processor; when the processor executes the computer program instructions, the call recovery method of any of the above embodiments is implemented.

[0012] In another aspect, a computer-readable storage medium is provided, on which computer program instructions are stored. When the computer program instructions run on a computer (such as a communication device or a call recovery device), the call recovery method of any of the above embodiments is implemented.

[0013] In another aspect, a computer program product is provided, which includes computer program instructions. When the computer program instructions are executed, the call recovery method of any of the above embodiments is implemented.

[0014] The technical solution provided by the embodiments of the present disclosure determines whether a core network element associated with a first session fails after the policy control network element creates the first session in response to a first session creation request of a proxy call session control network element (P-CSCF); when the core network element associated with the first session fails, the policy control network element sends a first request message to the P-CSCF. The first request message is used to request to terminate the first session and trigger a fault recovery process of the P-CSCF. In this way, once it is found that the core network element associated with the creation of the first session fails and causes a call failure, the fault recovery process of the P-CSCF is quickly triggered, so that the terminating-side user equipment can re-attach to the network and re-establish the first session to a normally operating core network element, thereby ensuring that subsequent calls are connected as soon as possible and improving the call success rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic flowchart of an IMS registration provided by an embodiment of the present disclosure;

[0016] Figure 2 It is a schematic diagram of an IMS system and a mobile communication network provided by an embodiment of the present disclosure;

[0017] Figure 3 Flow chart of a call recovery method provided by an embodiment of the present disclosure;

[0018] Figure 4 Interaction flow chart of a call recovery method provided by an embodiment of the present disclosure;

[0019] Figure 5 Interaction flow chart of another call recovery method provided by an embodiment of the present disclosure;

[0020] Figure 6 Structure diagram of a call recovery device provided by an embodiment of the present disclosure;

[0021] Figure 7 Structure diagram of a communication device provided by an embodiment of the present disclosure. Detailed implementation manners

[0022] Next, the technical solutions in the embodiments of the present disclosure will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present disclosure.

[0023] In the description of the present disclosure, unless otherwise specified, " / " means "or". For example, A / B may represent A or B. The "and / or" herein is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, "at least one" means one or more, and "a plurality" means two or more. The words such as "first" and "second" do not limit the quantity and execution order, and the words such as "first" and "second" do not necessarily limit to be different.

[0024] It should be noted that in the present disclosure, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the present disclosure should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Exactly speaking, the use of words such as "exemplary" or "for example" is intended to present relevant concepts in a specific manner.

[0025] Since the fourth-generation mobile communication technology (4G), voice calls and multimedia services in wireless communication systems have gradually migrated from the traditional circuit-switched domain to the IP multimedia subsystem (IMS) domain. This migration enables both voice and data services to be transmitted through the packet switched domain (data domain), thus greatly improving network efficiency and flexibility.

[0026] After a user attaches or registers to a mobile communication network, the system will establish a packet data network (PDN) connection or a protocol data unit (PDU) session specifically for IMS services. These connections and sessions are the basis for subsequent IMS services (such as IMS voice termination and origination). It can be seen that a successful IMS voice call involves the wireless communication network and the IMS system, and there are many types of network elements involved. With the rapid increase in the number of users and the continuous expansion of the network, the reliability of voice calls faces severe challenges. Therefore, considering various failure scenarios, how to ensure the rapid recovery of voice calls and improve the call success rate has become an urgent problem to be solved.

[0027] Exemplarily, Figure 1 Provide a schematic diagram of the IMS registration process, as Figure 1 shown, including the following steps:

[0028] Step 1, after the UE establishes a PDU session or a PDN session connection and obtains an IP address, the UE can initiate an IMS registration. The UE sends a first registration request message to the proxy-call session control function (P-CSCF). The first registration request message may include the UE identifier, the home domain name, the UE address, etc.

[0029] Step 2, after receiving the first registration request message, the P-CSCF checks the home domain name, selects the interrogating-call session control function (I-CSCF) according to the home domain, and sends a second registration request message to the selected I-CSCF. The second registration request message includes information such as the address of the P-CSCF, the user identifier, and the terminal address.

[0030] Steps 3 - 4, after receiving the second registration request message, the I-CSCF sends a query request message (such as Cx-Query / Cx-Select-Pull) to the home subscriber server (HSS) or the unified data function (UDM) to query information about the serving-call session control function (S-CSCF). The HSS verifies the UE based on the terminal identifier. After success, the HSS returns a query response message (such as Cx-Query Resp / Cx-Select-Pull Resp) to the I-CSCF. The query response message includes the identifier or name of the S-CSCF, and the capabilities of the S-CSCF.

[0031] Step 5, the I-CSCF queries the address of the S-CSCF based on the name or identifier of the S-CSCF. According to the queried S-CSCF address, the I-CSCF sends a third registration request message to the S-CSCF, which carries the address or name of the P-CSCF and the information of the UE identifier. The S-CSCF stores the relevant information of the P-CSCF.

[0032] Steps 6 - 7, the S-CSCF sends a store / retrieve request message (such as Cx-Put / Cx-Pull) to the HSS, which contains the relevant information of the UE. The relevant information of the UE includes the information of the S-CSCF of this UE (such as the address or name of the S-CSCF), and the identifier of this UE. The HSS stores the relevant information of this UE and returns a store / retrieve response message (such as Cx-PutResp / Cx-Pull Resp) to the S-CSCF, which contains user information, such as the information of the application server (AS) to be registered, etc.

[0033] Step 8, the S-CSCF returns a registration response message to the UE hop by hop through the I-CSCF and the P-CSCF. For example, the registration response message can be a 200ok message, which is used to notify the success of registration.

[0034] Among them, after the UE registers to the network, subsequent sessions can be carried out. When a call request arrives at the terminating call side, the terminating P-CSCF will trigger the policy and charging rule function (PCRF) / policy control function (PCF) to establish an Rx call. At this time, if the Public Data Network (PDN) control plane network element (PGW-C) / session management function (SMF) on the terminating call side, or the Public Data Network (PDN) user plane network element (PGW-U) / user plane function (UPF) network element fails, the current session will fail.

[0035] As can be seen from the above, in the scenario of IMS terminating call, when a core network element related to the PDN connection or PDU session established by the terminating call user equipment fails, data transmission will be blocked, and then the current terminating call is likely to fail. However, the failure at this time will not trigger any special processing of the terminating call network. Therefore, even if the calling party immediately calls the called party again after this call fails, the session may not be connected.

[0036] In view of this, the present disclosure provides a call recovery method. After the policy control network element creates a first session in response to a first session creation request from the proxy call session control network element P-CSCF, it determines whether a core network element associated with the first session fails; in the case where the core network element associated with the first session fails, the policy control network element sends a first request message to the P-CSCF, and the first request message is used to request to terminate the first session and trigger the fault recovery process of the P-CSCF.

[0037] In this way, once it is found that the core network element associated with the creation of the first session fails, causing the call to fail, the fault recovery process of the P-CSCF is quickly triggered, so that the terminating call side user equipment can re-attach to the network and rebuild the first session to a normally operating core network element, thereby ensuring that subsequent calls are connected as soon as possible and improving the call success rate.

[0038]

[0039] ​The call recovery method provided by the embodiments of the present disclosure can be applied to systems of multiple communication standards. For example, the systems to which the call recovery method provided by the embodiments of the present disclosure can be applied include, but are not limited to, long term evolution (LTE) systems, various versions evolved from LTE, 5G systems, ambient internet of things (ambient IoT) and other communication systems. In addition, the call recovery method provided by the embodiments of the present disclosure can also be applied to future-oriented communication systems (such as 6G communication systems), etc.

[0040] Figure 2 FIG. provides a schematic diagram of an IMS system and a mobile communication network according to an embodiment of the present disclosure.

[0041] As Figure 2As shown in the figure, the most important functional entities in the IMS are the call control entity and the home subscriber server. The IMS core network elements include: P-CSCF, I-CSCF, S-CSCF, IMS access gateway (IMS-AGW), and the IMS core network elements may also include HSS. The functions of the S-CSCF include: (1) identifying the local service identifier in the user service request and determining whether it belongs to the subscribed service according to the service attributes; (2) judging the service authority according to the user subscription information; (3) providing the processing of local services; (4) triggering the corresponding application server to process local services. Recording the call status of the user and completing the call control function, it is the most important service control entity. Since different S-CSCFs are connected to different ASs, different service functions can be completed. The P-CSCF is the first contact point of the user equipment in the IMS domain and completes the proxy function. Its functions are: (1) accepting the session initiation protocol (SIP) message, performing internal processing, and then forwarding it; (2) identifying the local service identifier in the user service request; (3) querying the S-CSCF that can provide local services according to the configuration information or other methods. The functions of the I-CSCF include: when the user registers, the I-CSCF queries the HSS to determine the S-CSCF for the user service, mainly considering network security and completing the network function. The functions of the HSS include: (1) recording the subscription data of each IMS user and cooperating with the call session control function (CSCF) to complete the most important routing function and roaming function; (2) providing authentication, authorization, IMS / IP address mapping, location positioning function, etc.; (3) accepting the query of the user subscription information by the access network S-CSCF and returning the user subscription information. The user subscription information includes: user number, address information; security information for authentication and authorization; supporting user registration and recording location information between different systems; user characteristic data.

[0042] The 5G core network (5G Core, 5GC) may include functional network elements such as the access and management mobility function (AMF), UDM, SMF, UPF, PCF, etc.

[0043] The evolved packet core (EPC) network elements include: Mobility Management Entity (MME), HSS, Serving Gateway (SGW), Packet Gateway Control (PGW), and PCRF. Among them, the MME is responsible for signaling processing and realizes control functions such as user mobility management, session management, and access authentication. The HSS stores user subscription information and realizes functions such as user data management and authentication. The SGW is responsible for data processing and realizes functions such as session management, data routing and forwarding, and downlink data caching in the idle mode. The PGW is the gateway to access the PDN, assigns IP addresses to users, and realizes functions such as session management, data routing and forwarding, etc. The PCRF realizes functions such as policy control of quality of service.

[0044] Among them, the UE can access the core network from the radio access network (RAN) (LTE for 4G or NR for 5G). After attachment or registration, the UE establishes a PDN connection or a PDU session for IMS services. After the establishment of the PDN connection or the PDU session is completed, the UE completes registration in the IMS system through the P-CSCF to the I / S-CSCF.

[0045] The above Figure 2 In the above, in the scenario of considering the integration of 4G and 5G, one or more systems can be combined. Among them, the control plane network elements in 4G and 5G can be co-located, and the user plane network elements can also be co-located. For example, the SMF can be co-located with the PGW-C, the UPF can be co-located with the PGW-U, the HSS can be co-located with the UDM, and the PCF can be co-located with the PCRF. Among the co-located network elements, they present their respective interfaces externally, and internal messages can be interacted in a customized way to achieve the deployment effect of a single 4G / 5G network.

[0046] In the embodiments of the present disclosure, the radio access network may include various forms of base stations, such as macro base stations, micro base stations (also referred to as small stations), relay stations, access points, new radio controllers (NR controllers), centralized units, radio remote heads, distributed units, transmission reception points (TRPs) or transmission points (TPs), or any other radio access devices, but the embodiments of the present disclosure are not limited thereto. Among them, in systems adopting different radio access technologies, the names of devices with radio access functions may be different. For example, radio access network devices may be next generation NodeBs (gNBs) in 5G mobile communication systems or base stations in future mobile communication systems. The embodiments of the present disclosure do not limit the specific technologies and specific device forms adopted by the radio access network.

[0047] In some embodiments, a base station (BS) may be a base station in Long Term Evolution (LTE), Long Term Evolution Advanced (LTE-A), or an evolved Node B (eNB or eNodeB), a base station device in a 5G network, or a base station in a future communication system, etc. The base station may include various macro base stations, micro base stations, home base stations, radio remotes, reconfigurable intelligent surfaces (RISs), routers, relays, TRPs, wireless fidelity (WIFI) devices, user equipment (UE), and other various network-side devices.

[0048] In some embodiments, the terminal may be a device with wireless transceiver functions. The terminal may be a passive device, an ambient IoT device, a mobile phone, a tablet (Pad), a computer with wireless transceiver functions, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, etc. Embodiments of the present disclosure do not limit the application scenarios. Sometimes, the terminal may also be referred to as a user, a user equipment (UE), an access terminal, a UE unit, a UE station, a mobile station, a mobile unit, a remote station, a remote terminal, a mobile device, a UE terminal, a wireless communication device, a UE agent, or a UE device, etc., and embodiments of the present disclosure do not limit this.

[0049] It should be noted that Figure 2 is only an exemplary framework diagram, Figure 2 the number of devices included in it, and the names of each device are not limited, and in addition to Figure 2 the devices shown, the communication system may further include other devices.

[0050] Embodiments of the present disclosure do not limit the application scenarios. The system architecture and service scenarios described in embodiments of the present disclosure are for more clearly illustrating the technical solutions of embodiments of the present disclosure, and do not constitute a limitation to the technical solutions provided by embodiments of the present disclosure. Those of ordinary skill in the art can know that with the evolution of the network architecture and the emergence of new service scenarios, the technical solutions provided by embodiments of the present disclosure are equally applicable to similar technical problems.

[0051] Embodiments of the present disclosure provide a call recovery method, which is applied to a policy control network element. As Figure 3 shown, the method includes the following steps:

[0052] S101. After the policy control network element creates a first session in response to a first session creation request from a proxy call session control function (P-CSCF), the policy control network element determines whether a core network element associated with the first session has failed.

[0053] Among them, the policy control network element can be one of the following: PCF, PCRF, and the integrated network element of PCF and PCRF.

[0054] The first session is a session between the policy control network element and the proxy call session control network element.

[0055] In some embodiments, the core network elements associated with the first session include a user plane network element and / or a control plane network element. The user plane network element at least includes at least one of the following: the public data network gateway user plane network element (PGW-U), and the user plane function network element UPF. The control plane network element at least includes at least one of the following: the public data network gateway control plane network element (PGW-C), and the session management network element (SMF).

[0056] In some embodiments, the control plane network element can also be an integrated network element of the public data network gateway control plane network element and the session management network element. The user plane network element can also be an integrated network element of the public data network gateway user plane network element and the user plane function network element UPF.

[0057] In some embodiments, the policy control network element determines whether a core network element associated with the first session fails, including:

[0058] The policy control network element sends a second request message to the control plane network element, and the second request message is used to request an update of the second session between the policy control network element and the control plane network element;

[0059] If the policy control network element does not receive any response message sent by the control plane network element within a preset duration, it determines that the control plane network element fails.

[0060] In some embodiments, the policy control network element determines whether a core network element associated with the first session fails, including:

[0061] The policy control network element sends a second request message to the control plane network element, and the second request message is used to request an update of the second session between the policy control network element and the control plane network element. The second request message includes first indication information, and the first indication information is used to instruct the control plane network element to detect whether the user plane network element fails;

[0062] The policy control network element receives a first response message sent by the control plane network element, and the first response message includes second indication information, and the second indication information is used to indicate that the user plane network element fails.

[0063] It can be understood that a policy control network element (such as a PCRF / PCF) can use the Gx interface to send a second request message to a control plane network element (such as a PGW-C / SMF). Among them, after the Rx interface is established, it is not necessary for the policy control network element to update the Gx interface in all cases. If the Gx interface needs to be updated, the method flow described in the above embodiments can be adopted when the policy control network element needs to determine whether a core network element associated with the first session has failed. If the Gx interface is not updated in most scenarios, the PCRF can determine the frequency of sending the second request message to the control plane network element by setting a timer or by counting, so as to avoid excessive second request messages sent by the policy control network element.

[0064] In some embodiments, the policy control network element sends a second request message to the control plane network element, including: the policy control network element sends the second request message to the control plane network element based on a first preset frequency, and the first preset frequency is determined based on timer configuration or counting. In this way, the sending of excessive second request messages is avoided, and congestion or overload caused by excessive requests is avoided, thereby enhancing the stability and reliability of the entire system and reducing unnecessary network traffic and computing resource consumption.

[0065] In some embodiments, the policy control network element determines whether a core network element associated with the first session has failed, including:

[0066] In the case of using a service-based interface between the policy control network element and the session management network element, the policy control network element sends a third request message to the session management network element, and the third request message includes third indication information for indicating the session management network element to detect whether a user plane network element has failed;

[0067] The policy control network element receives a second response message sent by the session management network element, and the second response message includes fourth indication information for indicating that the user plane network element has failed.

[0068] Exemplarily, if it is a 5G access system, a service-based interface (SBI) can be used between the PCF and the SMF. Therefore, the PCF can send a third request message (such as the Npcf_SMPolicyControl_UpdateNotify service operation) to the SMF, and the third request message includes third indication information for indicating the SMF to detect whether a user plane network element has failed. When the SMF detects that the user plane network element has failed, it sends a second response message corresponding to the third request message to the PCF, and the second response message includes fourth indication information for indicating that the user plane network element has failed.

[0069] In some embodiments, the policy control network element sends a third request message to the session management network element based on a second preset frequency, and the second preset frequency is determined based on timer configuration or counting method.

[0070] S102. When a core network element associated with the first session fails, the policy control network element sends a first request message to the P-CSCF. The first request message is used to request termination of the first session and trigger a fault recovery process of the P-CSCF.

[0071] Based on this, once it is found that the failure of the core network element associated with the creation of the first session causes a call failure, the fault recovery process of the P-CSCF is quickly triggered, so that the terminating user equipment can re-attach to the network and re-establish the first session to a normally operating core network element, thereby ensuring that subsequent calls can be connected as soon as possible and improving the call success rate.

[0072] Exemplarily, as Figure 4 shown, an interaction flowchart of a call recovery method is provided. After the P-CSCF on the called side (which can also be called the terminating network) triggers the establishment of the first session through the PCRF / PCF and then discovers that the PGW-C / SMF has failed, the PCRF / PCF triggers the fault recovery process of the P-CSCF. The specific steps are as follows:

[0073] S201 - S203. The S-CSCF on the calling side (which can also be called the originating network) receives a request message for session creation (denoted as the Invite message). If the calling side and the called side are not in the same network, the S-CSCF on the calling side sends the Invite message to the I-CSCF on the called side. The I-CSCF on the called side queries the S-CSCF on the called side and sends the Invite message to the S-CSCF on the called side. Otherwise, the S-CSCF on the calling side sends the Invite message to the S-CSCF on the called side, and the S-CSCF on the called side sends the Invite message to the P-CSCF on the called side.

[0074] S204 - S205. The P - CSCF on the called side sends a fourth request message (which can also be called the first session creation request) (e.g., Rx Authorization - Authentication - Request (AAR / Diameter AAR)) to the PCRF / PCF on the called side. The fourth request message is used to request the creation of a first session (e.g., the Rx session between the P - CSCF and the PCRF / PCF). The PCRF / PCF on the called side returns a fourth response message (which can also be called the first session creation response) (e.g., Rx Authorization - Authentication - Answer (AAA / Diameter AAA)) message. At this time, although the PCRF / PCF on the called side has replied with a response to the P - CSCF on the called side, since the PGW - C / SMF on the called side has failed, the P - CSCF on the called side cannot deliver the Invite message to the UE on the called side.

[0075] S206. The PCRF / PCF on the called side sends a second request message (e.g., Re - Auth - Request (RAR / Diameter RAR)) to the PGW - C / SMF on the called side. The second request message is used to request the update of the second session between the policy control network element and the control plane network element. The second request message may include first indication information, and the first indication information is used to indicate whether the PGW - C / SMF detects a failure of the user plane network element (e.g., PGW - U / UPF).

[0076] S207. Since the PGW - C / SMF on the called side has failed, the PCRF / PCF on the called side has not received any response message sent by the PGW - C / SMF within a preset time period. The PCRF / PCF on the called side determines that the PGW - C / SMF on the called side has failed. The PCRF / PCF on the called side actively sends a first request message (e.g., Diameter Abort - Session - Request (ASR / Diameter ASR)) to the P - CSCF on the called side. The first request message is used to request the termination of the first session (e.g., the Rx session between the P - CSCF and the PCRF / PCF) and trigger the failure recovery process of the P - CSCF on the called side. The first request message may also include relevant information about the failed core network element.

[0077] S208. The P - CSCF on the called side receives a third response message (e.g., Diameter Abort - Session - Answer (ASA / Diameter ASA)) corresponding to the replied first request message.

[0078] S209. The P-CSCF on the called side may choose to reply with a fifth response message to the S-CSCF on the called side according to the first request message received in S207. The fifth response message is used to indicate that the service is unavailable, or the P-CSCF on the called side chooses not to reply directly. Based on this, the S-CSCF on the called side can determine that the P-CSCF on the called side has failed at this time.

[0079] S210. Subsequently, the S-CSCF on the called side uses the P-CSCF fault recovery process defined in the related technology to trigger the UE to deactivate the IMS-related PDU session or PDN connection through the HSS and initiate session reconstruction (that is, the S-CSCF on the called side in the figure sends a Cx SAR to the HSS / UDM, and the HSS notifies the MME / AMF (P-CSCF) of the fault), triggering the IMS PDU session / PDN connection reconstruction. The specific implementation can refer to the related technology).

[0080] Exemplarily, as Figure 5 shown, an interaction flowchart of another call recovery method is provided. After the P-CSCF on the called side (which can also be called the terminating network) triggers the establishment of the first session through the PCRF / PCF, it is found that the PGW-C / SMF detects a failure in the user plane network element (such as PGW-U / UPF). The PCRF / PCF triggers the P-CSCF fault recovery process. The specific steps are as follows:

[0081] S301 - S303. The S-CSCF on the calling side (which can also be called the originating network) receives a request message for session creation (denoted as the Invite message). If the calling side and the called side are not in the same network, the S-CSCF on the calling side sends the Invite message to the I-CSCF on the called side. The I-CSCF on the called side queries the S-CSCF on the called side and sends the Invite message to the S-CSCF on the called side. Otherwise, the S-CSCF on the calling side sends the Invite message to the S-CSCF on the called side. The S-CSCF on the called side sends the Invite message to the P-CSCF on the called side.

[0082] S304 - S305. The P - CSCF on the called side sends a fourth request message (which can also be called the first session creation request) (e.g., Rx Authorization - Authentication - Request (AAR / Diameter AAR)) to the PCRF / PCF on the called side. The fourth request message is used to request the creation of a first session (e.g., the Rx session between the P - CSCF and the PCRF / PCF), and the PCRF / PCF on the called side returns a fourth response message (which can also be called the first session creation response) (e.g., Rx Authorization - Authentication - Answer (AAA / Diameter AAA)) message. At this time, although the PCRF / PCF on the called side has replied with a response to the P - CSCF on the called side, since the PGW - C / SMF on the called side has failed, the P - CSCF on the called side cannot deliver the Invite message to the UE on the called side.

[0083] S306. The PCRF / PCF on the called side sends a second request message (e.g., Re - Auth - Request (RAR / Diameter RAR)) to the PGW - C / SMF on the called side. The second request message is used to request an update of the second session between the PCRF / PCF and the PGW - C / SMF. The second request message includes a first indication information, and the first indication information is used to indicate whether the user plane network element (e.g., PGW - U / UPF) has failed.

[0084] S307. The PCRF / PCF on the called side receives a first response message sent by the PGW - C / SMF on the called side. The first response message includes a second indication information, and the second indication information is used to indicate that the user plane network element (e.g., PGW - U / UPF) has failed.

[0085] S308. The PCRF / PCF on the called side actively sends a first request message (e.g., Diameter Abort - Session - Request (ASR / Diameter ASR)) to the P - CSCF on the called side. The first request message is used to request the termination of the first session (e.g., the Rx session between the P - CSCF and the PCRF / PCF), and trigger the fault recovery process of the P - CSCF on the called side. The first request message may also include relevant information about the failed core network element.

[0086] S309. The P - CSCF on the called side receives a third response message (e.g., Diameter Abort - Session - Answer (ASA / Diameter ASA)) corresponding to the replied first request message.

[0087] S310. Based on the first request message received in S308, the P-CSCF on the called side may choose to reply with a fifth response message to the S-CSCF on the called side. The fifth response message is used to indicate that the service is unavailable, or the P-CSCF on the called side may choose not to reply directly. Based on this, the S-CSCF on the called side can determine that the P-CSCF on the called side has failed at this time.

[0088] S311. Subsequently, the S-CSCF on the called side uses the P-CSCF fault recovery process defined in the related technology to trigger the UE to activate the IMS-related PDU session or PDN connection through the HSS and initiate session reconstruction (that is, the S-CSCF on the called side in the figure sends a Cx SAR to the HSS / UDM, and the HSS notifies the MME / AMF (P-CSCF) of the fault), triggering the reconstruction of the IMS PDU session / PDN connection. The specific implementation can refer to the related technology).

[0089] It can be understood that, for example, PCRF, PCF, SMF, etc. can be specific functions loaded on hardware devices, but the processes and messages described here are completed through specific logical functions and do not depend on specific hardware implementations. This description is mainly because in the current network, these functions can be implemented by loading software, and there may not necessarily be specific physical entities corresponding to them. For example, different logical functions such as SMF and AMF can be loaded onto the same physical network element.

[0090] The above mainly introduces the solution of the embodiments of the present disclosure from the perspective of methods. The following also shows a call recovery device for performing the call recovery method in any of the above embodiments and its possible implementation manners. It can be understood that in order to implement the call recovery method, the call recovery device includes the corresponding hardware structure and / or software module for executing each function; those skilled in the art should easily realize that, combined with the algorithm steps of each example described in the embodiments of the present disclosure, the present disclosure can be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed in the way of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present disclosure.

[0091] The embodiments of the present disclosure can divide the call recovery device into functional modules according to the above method embodiments. For example, each functional module can be divided corresponding to each function, or two or more functions can be integrated into one functional module. The above integrated module can be implemented in the form of hardware or software. It should be noted that the division of modules in the embodiments of the present disclosure is illustrative, only a logical function division, and there can be other division methods in actual implementation. The following takes the example of dividing each functional module corresponding to each function for illustration.

[0092] Figure 6 FIG. 4 is a schematic structural diagram of a call recovery device provided by an embodiment of the present disclosure, which is applied to a policy control network element. The call recovery device 60 includes: a processing module 61 and a communication module 62.

[0093] The processing module 61 is configured to determine whether a core network element associated with the first session fails after the policy control network element creates a first session in response to a first session creation request of a proxy call session control function network element (P-CSCF).

[0094] The communication module 62 is configured to send a first request message to the P-CSCF when a core network element associated with the first session fails. The first request message is used to request to terminate the first session and trigger a fault recovery process of the P-CSCF.

[0095] In some embodiments, the core network element associated with the first session includes a user plane network element and / or a control plane network element; the user plane network element includes at least one of the following at least: a public data network gateway user plane network element, a user plane function network element (UPF); the control plane network element includes at least one of the following at least: a public data network gateway control plane network element, a session management network element.

[0096] In some embodiments, determining whether a core network element associated with the first session fails includes:

[0097] Sending a second request message to the control plane network element, where the second request message is used to request to update a second session between the policy control network element and the control plane network element;

[0098] If no response message sent by the control plane network element is received within a preset duration, it is determined that the control plane network element fails.

[0099] In some embodiments, the communication module 62 is configured to send a second request message to the control plane network element, where the second request message is used to request to update a second session between the policy control network element and the control plane network element, and the second request message includes a first indication information, where the first indication information is used to instruct the control plane network element to detect whether the user plane network element fails;

[0100] A processing module 61, configured to receive a first response message sent by a control plane network element, where the first response message includes second indication information for indicating that a user plane network element has failed.

[0101] In some embodiments, a communication module 62 is configured to send a second request message to the control plane network element based on a first preset frequency, where the first preset frequency is determined based on a timer configuration or a counting method.

[0102] In some embodiments, determining whether a core network element associated with a first session has failed includes:

[0103] The communication module 62 is configured to send a third request message to a session management network element when using a service-based interface between a policy control network element and the session management network element, where the third request message includes third indication information for indicating that the session management network element detects whether the user plane network element has failed;

[0104] The processing module 61 is configured to receive a second response message sent by the session management network element, where the second response message includes fourth indication information for indicating that the user plane network element has failed.

[0105] In some embodiments, the communication module 62 is configured to send a third request message to the session management network element based on a second preset frequency, where the second preset frequency is determined based on a timer configuration or a counting method.

[0106] When the functions of the above integrated modules are implemented in the form of hardware, embodiments of the present disclosure further provide a possible structure of a communication device, where the communication device is configured to execute the call recovery method provided by the embodiments of the present disclosure. As Figure 7 shown, the communication device 700 includes: a communication interface 703, a processor 702, and a bus 704. Optionally, the communication device may further include a memory 701.

[0107] The processor 702 may be a device that implements or executes various exemplary logical blocks, modules, and circuits described in conjunction with the embodiments of the present disclosure. The processor 702 may be a central processing unit, a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field-programmable gate array, or other programmable logic device, transistor logic device, hardware component, or any combination thereof. It may implement or execute various exemplary logical blocks, modules, and circuits described in conjunction with the embodiments of the present disclosure. The processor 702 may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc.

[0108] A communication interface 703 for connecting to other devices via a communication network. The communication network can be an Ethernet, a radio access network, a wireless local area network (WLAN), etc.

[0109] A memory 701 can be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions, or it can also be an electrically erasable programmable read-only memory (EEPROM), a magnetic disk storage medium, or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto.

[0110] As a possible implementation, the memory 701 can exist independently of the processor 702. The memory 701 can be connected to the processor 702 via a bus 704 for storing instructions or program code. When the processor 702 calls and executes the instructions or program code stored in the memory 701, the call recovery method provided by the embodiments of the present disclosure can be implemented.

[0111] In another possible implementation, the memory 701 can also be integrated with the processor 702.

[0112] A bus 704 can be an extended industry standard architecture (EISA) bus, etc. The bus 704 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 7 only a thick line is used to represent it in the figure, but it does not mean that there is only one bus or one type of bus.

[0113] Some embodiments of the present disclosure provide a computer-readable storage medium (for example, a non-transitory computer-readable storage medium). Computer program instructions are stored in the computer-readable storage medium. When the computer program instructions run on a computer, the computer is caused to execute the call recovery method described in any one of the above embodiments.

[0114] In an exemplary embodiment, the computer can be the above call recovery device, and the present disclosure does not limit the specific form of the computer.

[0115] In some examples, the above computer-readable storage medium may include, but is not limited to: magnetic storage devices (such as hard disks, floppy disks, or magnetic tapes, etc.), optical disks (such as compact disks (CDs), digital versatile disks (DVDs), etc.), smart cards, and flash memory devices (such as erasable programmable read-only memories (EPROMs), cards, sticks, or key drives, etc.). The various computer-readable storage media described in this disclosure may represent one or more devices and / or other machine-readable storage media for storing information. The term "machine-readable storage medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing, and / or carrying instructions and / or data).

[0116] An embodiment of the present disclosure provides a computer program product containing instructions. When the computer program product runs on a computer, it causes the computer to execute the call recovery method described in any one of the above embodiments.

[0117] As described above, the above are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present disclosure should be covered by the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A call recovery method, characterized in that: Applied to a policy control network element, the method comprises: After the policy control network element creates the first session in response to the first session creation request of the proxy call session control network element P-CSCF, determining whether a core network element associated with the first session fails; In the event that a core network element associated with the first session fails, a first request message is sent to the P-CSCF, where the first request message is used to request termination of the first session and trigger a fault recovery process of the P-CSCF.

2. The method according to claim 1, characterized in that The core network network elements associated with the first session include user plane network elements and / or control plane network elements; the user plane network elements include at least one of the following: public data network gateway user plane network element, user plane function network element UPF; the control plane network elements include at least one of the following: public data network gateway control plane network element, session management network element.

3. The method according to claim 2, characterized in that The determining whether a core network element associated with the first session fails includes: Sending a second request message to the control plane network element, where the second request message is used to request updating a second session between the policy control network element and the control plane network element; If no response message sent by the control plane network element is received within a preset time period, it is determined that a failure occurs in the control plane network element.

4. The method according to claim 2, characterized in that: The determining whether a core network element associated with the first session fails includes: Sending a second request message to the control plane network element, where the second request message is used to request updating of a second session between the policy control network element and the control plane network element, where the second request message includes first indication information, where the first indication information is used to instruct the control plane network element to detect whether a fault occurs in the user plane network element; A first response message sent by the control plane network element is received, where the first response message includes the second indication information, and the second indication information is used to indicate that a failure occurs in the user plane network element.

5. The method according to claim 3 or 4, characterized in that: The sending a second request message to the control plane network element includes: The second request message is sent to the control plane network element based on a first preset frequency, where the first preset frequency is determined based on a timer configuration or a counting method.

6. The method according to claim 2, characterized in that The determining whether a core network element associated with the first session fails includes: In the case where a service-based interface is used between the policy control network element and the session management network element, sending a third request message to the session management network element, where the third request message includes third indication information, and the third indication information is used to instruct the session management network element to detect whether a fault occurs in the user plane network element; A second response message sent by the session management network element is received, where the second response message includes the fourth indication information, and the fourth indication information is used to indicate that a failure occurs in the user plane network element.

7. The method according to claim 6, characterized in that The policy control network element sends a third request message to the session management network element, including: The third request message is sent to the session management network element based on a second preset frequency, where the second preset frequency is determined based on a timer configuration or a counting method.

8. A communication device, characterized in that: include: Memory and processor; Memory and processor coupling; The memory is used to store instructions executable by the processor; When the processor executes the instructions, the method according to any one of claims 1 to 7 is performed.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and when the computer instructions are executed on a communication device, the communication device is caused to execute the method according to any one of claims 1 to 7.

10. A computer program product, characterized in that When the computer program product is executed, the method according to any one of claims 1 to 7 is implemented.

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