Call method based on IMS (IP Multimedia Subsystem) and electronic equipment

Abstract

The invention provides a calling method based on an IMS system and electronic equipment, and relates to the technical field of communication. The method comprises the following steps: a P-CSCF receives an SIP call request message sent by an S-CSCF after session management, and obtains an IMPU of a called IMS terminal according to the SIP call request message; according to the IMPU of the called IMS terminal, obtaining a second IP address of the called IMS terminal and a second target UPF identifier corresponding to the second IP address; modifying a destination address of an IP packet in the SIP call request message into a second IP address, and querying to obtain a fourth IP address of a second target UPF; and sending the SIP call request message to the second target UPF to enable the second target UPF to forward the modified SIP call request message to the called IMS terminal, so that the SIP call request message initiated by the calling IMS terminal can be accurately forwarded to the called IMS terminal without introducing a complex routing update mechanism.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a calling method and electronic device based on an IMS system. Background Art

[0002] IP Multimedia Subsystem (IMS) is a new form of multimedia service that can meet the needs of terminal customers for newer and more diversified multimedia services. IMS is considered to be the core technology of the next generation network and an important way to solve the integration of mobile and fixed networks and introduce differentiated services such as triple integration of voice, data and video.

[0003] Existing, when deploying an IMS system in a fifth generation mobile communication technology (5th generation mobile networks or 5th generation wireless systems, 5th-Generation, 5G) network, the IMS system and the user plane function UPF are usually centrally deployed in the same location, and most terminals access the IMS system from the same UPF.

[0004] However, the existing IMS deployment method does not take into account the deployment environment of industrial private networks. In such environments, multiple UPFs are usually deployed in the network to cover different factory operation areas. Terminals usually access the IMS system through different UPFs for voice communication. This will cause the IMS to be unable to determine which UPF to forward the user's call request after receiving the user's call request. Therefore, the existing technology often requires the introduction of a complex routing update mechanism in the local area network. Summary of the invention

[0005] The purpose of the present application is to provide a calling method and electronic device based on the IMS system to address the deficiencies in the above-mentioned prior art, which can realize accurate paging of IMS terminals without introducing a complex routing update mechanism in the local area network.

[0006] To achieve the above purpose, the technical solution adopted in the embodiment of the present application is as follows:

[0007] In a first aspect, the present invention provides a calling method based on an IMS system, which is applied to a proxy call session control function P-CSCF in an IP multimedia subsystem IMS, wherein the IMS system is communicatively connected with a plurality of user plane functions UPF, and the method comprises:

[0008] Receiving a session initiation protocol SIP call request message sent by a service call session control function S-CSCF after performing session management, and acquiring an IP multimedia private user identity IMPU of the called IMS terminal according to the SIP call request message, wherein the SIP call request message is marked with its corresponding first target UPF identity by the first target UPF corresponding to the calling IMS terminal, and carries the IMPU of the calling IMS terminal, the first IP address of the calling IMS terminal, and the IMPU of the called IMS terminal;

[0009] According to the IMPU of the called IMS terminal, query and obtain the second IP address of the called IMS terminal and the second target UPF identifier corresponding to the called IMS terminal;

[0010] According to the second IP address, modify the destination address of the IP packet in the SIP call request message to the second IP address, and query and obtain the fourth IP address of the second target UPF according to the second target UPF identifier;

[0011] The SIP call request message is sent to the second target UPF corresponding to the fourth IP address, so that the second target UPF forwards the SIP message in the modified SIP call request message to the called IMS terminal.

[0012] In an optional embodiment, the method further comprises:

[0013] receiving a SIP call response message forwarded by the S-CSCF, where the SIP call response message is generated by the called IMS terminal according to the SIP call request message and forwarded to the S-CSCF through the second target UPF, and the SIP call response message carries the IMPU of the called IMS terminal, the second IP address of the called IMS terminal, and the IMPU of the calling IMS terminal;

[0014] According to the IMPU of the calling IMS terminal, query and obtain the first IP address of the calling IMS terminal and the third IP address of the first target UPF corresponding to the calling IMS terminal;

[0015] The SIP call response message is sent to the first target UPF corresponding to the third IP address, so that the first target UPF forwards the SIP call response message to the calling IMS terminal based on the first IP address.

[0016] In an optional implementation manner, before receiving the SIP call request message sent by the S-CSCF after performing session management, the method further includes:

[0017] receiving a SIP call request message sent by a first target UPF corresponding to the calling IMS terminal, wherein the SIP call request message is obtained by marking a SIP initial call request message by the first target UPF according to its corresponding first target UPF identifier, and the SIP initial call request message is generated by the calling IMS terminal;

[0018] Generate a local SIP call record according to the SIP call request message, and forward the SIP call request message to the S-CSCF, so that the S-CSCF performs session management processing, wherein the local SIP call record includes: the IMPU of the calling IMS terminal corresponding to each SIP call request message within a preset time period, the UPF identifier corresponding to the calling IMS terminal, and the IP address corresponding to the calling IMS terminal.

[0019] In an optional implementation manner, before receiving the SIP call request message sent by the first target UPF corresponding to the calling IMS terminal, the method further includes:

[0020] Detecting the destination port number of the uplink message through the first target UPF;

[0021] If it is detected that the destination port number of the uplink message is a preset port number, determining that the uplink message is a SIP initial call request message;

[0022] The SIP call request message is obtained by marking the SIP initial call request message through the first target UPF.

[0023] In an optional implementation manner, querying and acquiring the second IP address of the called IMS terminal and the second target UPF identifier corresponding to the called IMS terminal according to the IMPU of the called IMS terminal includes:

[0024] According to the IMPU of the called IMS terminal, the second IP address of the called IMS terminal and the second target UPF identifier corresponding to the called IMS terminal are queried and acquired from the local SIP call record or the local SIP registration record.

[0025] In an optional embodiment, the method further comprises:

[0026] Receive a SIP registration message sent by a third target UPF corresponding to the registered IMS terminal, where the SIP registration message is obtained by the third target UPF marking a SIP initial registration message according to its corresponding third target UPF identifier, and the SIP initial registration message is generated by the registered IMS terminal;

[0027] The SIP registration message is forwarded to an inquiry call session control function I-CSCF, so that the terminal registration process is performed through the I-CSCF.

[0028] In an optional implementation manner, before forwarding the SIP registration message to the query call session control function I-CSCF, the method further includes:

[0029] Generate a SIP registration record according to the SIP registration message, wherein the SIP registration record includes: an IMPU of the registered IMS terminal and a UPF identifier corresponding to the registered IMS terminal;

[0030] According to the SIP registration record, the local SIP registration record is updated.

[0031] In an optional implementation manner, updating the local SIP registration record according to the SIP registration record includes:

[0032] If it is determined that the IMPU of the registered IMS terminal exists in the local SIP registration record, updating the local SIP registration record according to the current UPF identifier corresponding to the registered IMS terminal;

[0033] If it is determined that the IMPU of the registered IMS terminal does not exist in the local SIP registration record, the SIP registration record is added to the local SIP registration record.

[0034] In a second aspect, the present invention provides a calling method based on an IMS system, which is applied to a second target user plane function UPF corresponding to a called terminal, wherein the second target UPF is connected to an IP multimedia subsystem IMS for communication, and the method comprises:

[0035] Receive a modified SIP call request message sent by a proxy call session control function P-CSCF in the IMS according to the fourth IP address of the second target UPF; wherein the modified SIP call request message is obtained by modifying the destination address of the IP packet in the SIP call request message to the second IP address of the called IMS terminal, and the SIP call request message is sent to the P-CSCF after session management by the service call session control function S-CSCF; the SIP call request message is marked with the first target UPF identifier corresponding to the calling IMS terminal by the first target UPF corresponding to the calling IMS terminal, and carries the IMPU of the calling IMS terminal, the first IP address of the calling IMS terminal, and the IMPU of the called IMS terminal; the fourth IP address of the second target UPF is obtained by the P-CSCF according to the second target UPF identifier corresponding to the called IMS terminal, the second IP address of the called IMS terminal and the second target UPF identifier corresponding to the called IMS terminal are obtained by the P-CSCF according to the IMPU of the called IMS terminal, and the IMPU of the called IMS terminal is obtained by the P-CSCF according to the SIP call request message;

[0036] The SIP message in the modified SIP call request message is forwarded to the called IMS terminal.

[0037] In a third aspect, the present invention provides an electronic device, comprising: a processor, a storage medium and a bus, wherein the storage medium stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor communicates with the storage medium through the bus, and the processor executes the machine-readable instructions to perform the steps of the calling method based on the IMS system as described in any of the aforementioned implementations.

[0038] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the calling method based on the IMS system as described in any of the aforementioned implementations are executed.

[0039] The beneficial effects of this application are:

[0040] In the calling method and electronic device based on the IMS system provided by the embodiment of the present application, the method is applied to the proxy call session control function P-CSCF in the IP multimedia subsystem IMS, and the IMS system is connected in communication with multiple user plane functions UPF. The method includes: receiving a session initiation protocol SIP call request message sent by the service call session control function S-CSCF after performing session management, and obtaining the IP multimedia private user identity IMPU of the called IMS terminal according to the SIP call request message, wherein the SIP call request message is marked with the first target UPF corresponding to the calling IMS terminal and carries the IMPU of the calling IMS terminal, the first IP address of the calling IMS terminal, and the IMPU of the called IMS terminal; according to the called IMS terminal, the calling IMS terminal receives the IMPU of the called IMS terminal from the calling IMS terminal, and the calling IMS terminal receives the IMPU of the called IMS terminal from the calling IMS terminal. The IMPU of the MS terminal is used to query and obtain the second IP address of the called IMS terminal and the second target UPF identifier corresponding to the called IMS terminal; according to the second IP address, the destination address of the IP packet in the SIP call request message is modified to the second IP address, and according to the second target UPF identifier, the fourth IP address of the second target UPF is queried and obtained; the SIP call request message is sent to the second target UPF corresponding to the fourth IP address, so that the second target UPF forwards the SIP message in the modified SIP call request message to the called IMS terminal based on the second IP address, so that the IMS system can accurately forward the SIP call request message initiated by the calling IMS terminal to the called IMS terminal when multiple UPFs are connected, without introducing a complex routing update mechanism in the local area network. Moreover, the implementation of the method of the present application does not require the modification of the IMS terminal, and has the characteristic of being easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 is a schematic diagram of a network architecture applicable to the method provided in the embodiment of the present application;

[0043] Figure 2 A flowchart of a calling method based on an IMS system provided in an embodiment of the present application;

[0044] Figure 3 A flowchart of another IMS-based calling method provided in an embodiment of the present application;

[0045] Figure 4A flowchart of another IMS-based calling method provided in an embodiment of the present application;

[0046] Figure 5 A flowchart of another IMS-based calling method provided in an embodiment of the present application;

[0047] Figure 6 A flowchart of another IMS-based calling method provided in an embodiment of the present application;

[0048] Figure 7 A flowchart of another IMS-based calling method provided in an embodiment of the present application;

[0049] Figure 8 A communication interaction diagram of a calling method based on an IMS system provided in an embodiment of the present application;

[0050] Fig. 9 A schematic diagram of functional modules of a calling device based on an IMS system provided in an embodiment of the present application;

[0051] Fig.10 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0053] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0054] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0055] The technical solutions of the embodiments of the present application can be applied to various local communication systems, such as: global system for mobile communications (GSM) system, code division multiple access (CDMA) system, wideband code division multiple access (WCDMA) system, general packet radio service (GPRS), long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), universal mobile telecommunication system (UMTS), worldwide interoperability for microwave access (WiMAX) communication system, fifth generation (5G) communication system or future new radio access technology (NR), etc.

[0056] Figure 1 Schematic diagram of a network architecture applicable to the method provided in the embodiment of the present application. Figure 1 As shown, the network architecture can be, for example, a non-roaming architecture, which can be integrated with an IP Multimedia Subsystem (IMS), wherein the IMS runs together with the service infrastructure (SBA) in 5G, allowing service components (such as AMF, SMF) to interact as modular services, promoting rapid deployment and scalable communication in network slices; IMS uses control and user plane separation (CUPS) in 5G to effectively handle signaling and media traffic, which is crucial for optimizing user plane resource management, especially for delay-sensitive services.

[0057] In addition, refer to Figure 1 As shown, the network architecture may specifically include the following network elements:

[0058] 1. User equipment (UE): can be called user equipment, terminal, access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, wireless communication device, user agent or user device. UE can also be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a 5G network or a terminal device in a public land mobile communication network (PLMN) to be evolved in the future, etc. It can also be an end device, a logical entity, an intelligent device, such as a mobile phone, an intelligent terminal and other terminal devices, or a server, a gateway, a base station, a controller and other communication devices, or an Internet of Things device, such as a sensor, an electric meter, a water meter and other Internet of Things (IoT) devices. The embodiments of the present application are not limited to this.

[0059] 2. Access network (AN): provides network access for authorized users in a specific area, and can use transmission tunnels of different qualities according to the user level, business requirements, etc. The access network can be an access network that uses different access technologies. There are currently two types of wireless access technologies: 3rd generation partnership project (3GPP) access technology (such as the wireless access technology used in 3G, 4G or 5G systems) and non-3GPP access technology. 3GPP access technology refers to access technology that complies with 3GPP standards and specifications. The access network that uses 3GPP access technology is called a radio access network (RAN), where the access network equipment in the 5G system is called the next generation Node Base station (gNB). Non-3GPP access technology refers to access technology that does not comply with 3GPP standards and specifications, for example, air interface technology represented by access points (APs) in WIFI.

[0060] An access network that implements access network functions based on wireless communication technology can be called a radio access network (RAN). The radio access network can manage wireless resources, provide access services to terminals, and then complete the forwarding of control signals and user data between terminals and the core network.

[0061] The access network equipment may include equipment in the access network that communicates with the wireless terminal over the air interface through one or more sectors. The access network system may be used to convert received air frames to and from Internet Protocol (IP) packets, acting as a router between the wireless terminal and the rest of the access network, which may include an IP network. The wireless access network system may also coordinate the management of attributes of the air interface. It should be understood that the access network equipment includes but is not limited to: evolved node B (eNB), radio network controller (RNC), node B (NB), base station controller (BSC), base transceiver station (BTS), home base station (for example, home evolved node B, or home node B, HNB), base band unit (BBU), access point (AP) in wireless fidelity (WIFI) system, wireless relay node, wireless backhaul node, transmission point (transmission and reception point, TRP or transmission point, TP), etc., and can also be 5G, such as NR, gNB in ​​the system, or, transmission point (TRP or TP), one or a group of (including multiple antenna panels) antenna panels of a base station in the 5G system, or, it can also be a network node constituting a gNB or a transmission point, such as a baseband unit (BBU)), or, a distributed unit (DU), etc.

[0062] In some deployments, the gNB may include a centralized unit (CU) and a DU. The gNB may also include a radio unit (RU). The CU implements some of the functions of the gNB, and the DU implements some of the functions of the gNB. For example, the CU implements the functions of the radio resource control (RRC) and packet data convergence protocol (PDCP) layers, and the DU implements the functions of the radio link control (RLC), media access control (MAC), and physical (PHY) layers. Since the information of the RRC layer will eventually become the information of the PHY layer, or the information of the PHY layer will be converted into

[0063] Therefore, under this architecture, high-level signaling, such as RRC layer signaling, can also be considered to be sent by DU, or, sent by DU+CU. It can be understood that the access network device can be a CU node, or a DU node, or a device including a CU node and a DU node. In addition, the CU can be divided into an access network device in the access network (radio access network, RAN), and the CU can also be divided into an access network device in the core network (core network, CN), which is not limited here.

[0064] 3. Access and mobility management function (AMF) entity: mainly used for mobility management and access management, etc., and can be used to implement other functions of the mobility management entity (MME) except session management, such as lawful interception or access authorization (or authentication). In the embodiment of the present application, it can be used to implement the functions of the access and mobility management network element.

[0065] 4. Session management function (SMF) entity: mainly used for session management, UE Internet Protocol (IP) address allocation and management, selection of endpoints for manageable user plane functions, policy control, or charging function interfaces, and downlink data notification, etc. In the embodiment of the present application, it can be used to implement the function of the session management network element.

[0066] 5. User Plane Function (UPF) entity: i.e., data plane gateway. It can be used for packet routing and forwarding, or quality of service (QoS) processing of user plane data, etc. User data can be accessed to the data network (DN) through this network element. In the embodiment of the present application, it can be used to implement the function of the user plane gateway.

[0067] 6. Policy control function (PCF) entity: a unified policy framework used to guide network behavior and provide policy rule information to control plane functional network elements (such as AMF, SMF network elements, etc.).

[0068] 7. Unified data management (UDM) entity: used to process user identification, access authentication, registration, or mobility management, etc.

[0069] 8. N3IWF (Non-3GPP Inter Working Function): Responsible for connecting untrusted non-3GPP access networks (such as Wi-Fi) to the 5G core network. The UE establishes an IPsec tunnel with the N3IWF, and the N3IWF accesses the control plane and user plane of the 5G core network through the N2 interface and the N3 interface respectively.

[0070] 9. Network exposure function (NEF) network element: It serves as the interface between the 5G core network and other external services so that third-party applications and services can securely access network resources and services. Its main functions include: Service exposure: NEF is responsible for exposing services and functions in the 5G network so that external applications and services can call these services; Policy and permission management: NEF ensures that only authenticated and authorized applications and services can access specific network functions; Data conversion: NEF handles the conversion of data formats to ensure compatibility and interoperability between different systems; Traffic filtering and monitoring: NEF can filter and monitor the traffic passing through it to protect the network from malicious behavior; Event notification: NEF can send event notifications to external entities, such as applications, when certain important events occur in the network.

[0071] In this network architecture, Figure 1As shown, the N1 interface is the reference point between the terminal and the AMF entity; the N2 interface is the reference point between the AN and the AMF entity, which is used for sending non-access stratum (NAS) messages, etc.; the N3 interface is the reference point between the (R)AN and the UPF entity, which is used for transmitting user plane data, etc.; the N4 interface is the reference point between the SMF entity and the UPF entity, which is used for transmitting information such as tunnel identification information of the N3 connection, data cache indication information, and downlink data notification messages; the N6 interface is the reference point between the UPF entity and the DN, which is used for transmitting user plane data, etc.

[0072] In addition, if Figure 1 As shown, NEF network elements, network storage function (Network Repository Function, NRF) network elements, application function (Application Function, AF) network elements, PCF network elements, unified data repository (Unified Data Repository, UDR) network elements, UDM network elements, AMF network elements and SMF network elements can use the service-oriented interfaces provided to the outside to achieve communication. For example, the service-oriented interface provided by the NEF network element to the outside is the Nnef interface, the service-oriented interface provided by the UDM network element to the outside is the Nudm interface, the service-oriented interface provided by the AMF network element to the outside is the Namf interface, the service-oriented interface provided by the AF network element to the outside is the Naf interface, the service-oriented interface provided by the SMF network element to the outside is the Nsmf interface, the service-oriented interface provided by the PCF network element to the outside is the Npcf interface, and the service-oriented interface provided by the UDR network element to the outside is the Nudr interface.

[0073] It should be understood that the above-mentioned network architecture applied to the embodiments of the present application is merely an example of a network architecture described from the perspective of a traditional point-to-point architecture and a service-oriented architecture. The network architecture applicable to the embodiments of the present application is not limited to this. Any network architecture that can realize the functions of the above-mentioned network elements is applicable to the embodiments of the present application.

[0074] It should also be understood that Figure 1 The AMF entity, SMF entity, UPF entity, PCF entity, and UDM entity shown in the figure can be understood as network elements used to implement different functions in the core network, for example, they can be combined into network slices as needed. These core network network elements can be independent devices or integrated into the same device to implement different functions, which is not limited in this application.

[0075] In the following text, for the sake of convenience, the entity used to implement AMF will be denoted as AMF, and the entity used to implement PCF will be denoted as PCF. It should be understood that the above naming is only used to distinguish different functions, and does not mean that these network elements are independent physical devices. The present application does not limit the specific form of the above network elements. For example, they can be integrated in the same physical device, or they can be different physical devices. In addition, the above naming is only for the convenience of distinguishing different functions, and should not constitute any limitation on the present application. The present application does not exclude the possibility of using other names in 5G networks and other future networks. For example, in a 6G network, some or all of the above network elements may use the terminology in 5G, or other names may be used. A unified explanation is given here, and no further details will be given below.

[0076] It should also be understood that Figure 1 The interface name between the network elements is only an example. The interface name in the specific implementation may be other names, and this application does not specifically limit this. In addition, the name of the message (or signaling) transmitted between the above network elements is only an example and does not constitute any limitation on the function of the message itself.

[0077] In addition, the working principle of IMS in the above network architecture can be seen in the following content. IMS is an IP-based communication architecture designed to provide multimedia and voice services. Its core components include: Call Session Control Function (CSCF), Home Subscriber Server (HSS), Media Gateway Control Function (MGCF) and Media Resource Function (MRF).

[0078] Among them, Call Session Control Function (CSCF): CSCF is responsible for managing the establishment, modification and termination of user sessions. CSCF uses Session Initiation Protocol (SIP) to manage user sessions. It is divided into three categories: Proxy CSCF (P-CSCF), Serving CSCF (S-CSCF) and Inquiry CSCF (I-CSCF). Proxy CSCF (P-CSCF), as the first contact point between the user equipment (UE) and the network, is responsible for forwarding signaling messages; Serving CSCF (S-CSCF), handles the logical control of the session, such as user authentication and session management; Inquiry CSCF (I-CSCF), as an agent of S-CSCF, helps select the correct S-CSCF instance.

[0079] Home Subscriber Server (HSS): HSS stores user identity information and configuration files and is responsible for user authentication and authorization.

[0080] Media Gateway Control Function (MGCF): MGCF controls the signaling conversion between IMS and traditional circuit-switched networks.

[0081] Media Resource Function (MRF): The MRF is responsible for media processing tasks such as transcoding, recording, and conference bridging.

[0082] Taking 5G network as an example, the IMS system deployed in 5G network is currently mainly built for public network users, usually deployed in the same location as UPF, and users mostly access the IMS system from the same UPF. However, the existing IMS deployment method does not take into account the deployment environment of industrial private network. In such environment, multiple UPFs are usually deployed in the network to cover different factory operation areas. Users usually access the IMS system through different UPFs for voice communication. This results in the IMS being unable to determine which UPF to forward the user's call request after receiving the user's call request. Therefore, the existing technology often requires the introduction of complex routing update mechanisms in the local area network.

[0083] In view of this, the present application provides a calling method based on the IMS system, which can simplify the user call request processing process and support the IMS system to accurately page the target user among multiple UPFs, and has the characteristics of simple implementation.

[0084] Figure 2 A flow chart of a calling method based on an IMS system provided in an embodiment of the present application, wherein the executor of the method may be a proxy call session control function P-CSCF in the above-mentioned IP multimedia subsystem IMS, and the IMS system is connected in communication with multiple user plane functions UPFs. The method may be applicable to voice communication between any two IMS terminals, wherein the terminal that actively initiates a SIP call request may be referred to as a calling IMS terminal, and the terminal that receives the SIP call request may be referred to as a called IMS terminal. It should be noted that the IMS terminal in the embodiment of the present application refers to a UE configured with an IMS client software, allowing users to initiate and receive IMS services (such as VoLTE, video calls, etc.) through the device. The IMS terminal is a specific application scenario of the UE, focusing on IP multimedia services.

[0085] It should be noted that the P-CSCF network element in the IMS system has a UPF network element list pre-established locally. The UPF network element list may include multiple UPF records. One UPF may correspond to one UPF record. The representation of each UPF record may be<UPF_IP,UPF_ID> . Among them, UPF_IP is the IP address of the N6 interface of UPF, and UPF_ID is the device identifier of UPF in the private network. For the same description below, please refer to the description here. It should be noted that it may be different depending on the number of UPFs in the network architecture.

[0086] like Figure 2 As shown, the method may include:

[0087] S101. Receive a Session Initiation Protocol SIP call request message sent by a Serving-Call Session Control Function S-CSCF after performing session management, and obtain an IP Multimedia Private User Identity IMPU of a called IMS terminal according to the SIP call request message.

[0088] The SIP call request message is marked with the first target UPF identifier corresponding to the calling IMS terminal by the first target UPF corresponding to the calling IMS terminal, and carries the IMPU of the calling IMS terminal, the first IP address of the calling IMS terminal, and the IMPU of the called IMS terminal.

[0089] Among them, the first target UPF corresponding to the calling IMS terminal is the UPF that is communicatively connected to the calling IMS terminal; the second target UPF corresponding to the called IMS terminal is the UPF that is communicatively connected to the called IMS terminal.

[0090] During the call process, the calling IMS terminal can send the generated SIP initial call request message to the corresponding first target UPF. The first target UPF can generate a SIP call request message after marking the SIP initial call request message with its corresponding first target UPF identifier. The generated SIP call request message can be forwarded to the S-CSCF through the P-CSCF, and the S-CSCF performs session management processing. For example, it can decide whether to allow the call and is responsible for correctly routing the call request to the destination, etc., which is not limited here.

[0091] If the S-CSCF determines that the call is allowed, the S-CSCF may further forward the SIP call request message to the P-CSCF, and the P-CSCF will perform further call forwarding.

[0092] The SIP call request message may carry the IMPU (IP Multimedia Public Identity) of the calling IMS terminal, the first IP address of the calling IMS terminal, and the IMPU of the called IMS terminal.

[0093] S102: According to the IMPU of the called IMS terminal, query and obtain a second IP address of the called IMS terminal and a second target UPF identifier corresponding to the called IMS terminal.

[0094] Optionally, local SIP call records or local SIP registration records may be pre-stored in the P-CSCF. Among them, the local SIP call records can be generated during the call request phase initiated by the IMS terminal, and may include: the IMPU of the IMS terminal called by each SIP call request message within a preset time period, the UPF identifier corresponding to the called IMS terminal, and the IP address corresponding to the called IMS terminal. The local SIP registration records can be generated during the registration phase of the IMS terminal, and may include: the IMPU of the registered IMS terminal, the UPF identifier corresponding to the registered IMS terminal. It should be noted that the IMPU of the registered IMS terminal may carry the IP address of the registered IMS terminal.

[0095] Optionally, when specifically querying, the P-CSCF can query and obtain the second target UPF identifier and the second IP address corresponding to the called IMS terminal based on the IMPU of the called IMS terminal through the local SIP call records or local SIP registration records stored therein. If there is a matching record, the second target UPF identifier and the second IP address in the record are read. Otherwise, the SIP call request message is discarded. In some embodiments, when specifically querying, the second target UPF identifier and the second IP address corresponding to the called IMS terminal can be queried and obtained based on the latest record corresponding to the called IMS terminal in the local SIP call records and local SIP registration records.

[0096] S103. Modify the destination address of the IP packet in the SIP call request message to the second IP address according to the second IP address, and query and obtain the fourth IP address of the second target UPF according to the second target UPF identifier.

[0097] Optionally, after the P-CSCF retrieves and obtains the second IP address of the called IMS terminal, it can modify the destination address of the IP packet carrying the SIP call request message from the IP address of the P-CSCF to the IP address of the called terminal, so that the SIP call request message can be forwarded to the called terminal based on this subsequently.

[0098] Of course, in some embodiments, after the P-CSCF retrieves and obtains the second IP address of the called IMS terminal, it modifies the IMPU of the called IMS terminal in the SIP call request message, and its specific manifestation form is <sip:username@the second IP address of the called IMS terminal>. The present application does not limit the specific modification method herein, and can be flexibly selected according to the actual application scenario.

[0099] Furthermore, the P-CSCF retrieves the local UPF network element list with the retrieved second target UPF identifier as the index. If there is a matching record, the fourth IP address of the second target UPF is read. Otherwise, the SIP call request message is discarded.

[0100] Among them, the local UPF network element list stored in the P-CSCF may include: the UPF_ID that communicates with the P-CSCF (that is, the device identifier of the UPF in the private network) and the IP address corresponding to the UPF (that is, the IP address of the N6 interface of the UPF).

[0101] S104: Send the SIP call request message to the second target UPF corresponding to the fourth IP address, so that the second target UPF forwards the SIP message in the modified SIP call request message to the called IMS terminal.

[0102] After retrieving and obtaining the fourth IP address of the second target UPF corresponding to the called IMS terminal, the P-CSCF can use the fourth IP address as the destination address, encapsulate the SIP call request message into a GRE tunnel message, and send it to the local area network; after the second target UPF receives the GRE tunnel message from the local area network, it can extract the IP packet therein, and forward the SIP message to the called IMS terminal according to the destination address indicated by the IP packet, thereby realizing that the IMS system can accurately forward the SIP call request message initiated by the calling IMS terminal to the called IMS terminal when connecting multiple UPFs, without introducing a complex routing update mechanism in the local area network.

[0103] In summary, the embodiment of the present application provides a calling method based on an IMS system, the method is applied to a proxy call session control function P-CSCF in an IP multimedia subsystem IMS, the IMS system is connected in communication with a plurality of user plane functions UPF, the method comprising: receiving a session initiation protocol SIP call request message sent by a service call session control function S-CSCF after performing session management, and acquiring an IP multimedia private user identity IMPU of a called IMS terminal according to the SIP call request message, wherein the SIP call request message is marked with a first target UPF identity corresponding to the calling IMS terminal and carries the IMPU of the calling IMS terminal, the first IP address of the calling IMS terminal, and the IMPU of the called IMS terminal; according to the called IM According to the IMPU of the S terminal, the second IP address of the called IMS terminal and the second target UPF identifier corresponding to the called IMS terminal are queried and obtained; according to the second IP address, the destination address of the IP packet in the SIP call request message is modified to the second IP address, and according to the second target UPF identifier, the fourth IP address of the second target UPF is queried and obtained; the SIP call request message is sent to the second target UPF corresponding to the fourth IP address, so that the second target UPF forwards the SIP message in the modified SIP call request message to the called IMS terminal based on the second IP address, so that the IMS system can accurately forward the SIP call request message initiated by the calling IMS terminal to the called IMS terminal when multiple UPFs are connected, without introducing a complex routing update mechanism in the local area network. Moreover, the implementation of the method of the present application does not require the modification of the IMS terminal, and has the characteristic of being easy to implement.

[0104] Figure 3 A flowchart of another IMS-based calling method provided in an embodiment of the present application. Figure 3 As shown, the above method also includes:

[0105] S201. Receive a SIP call response message forwarded by an S-CSCF. The SIP call response message is generated by the called IMS terminal according to a SIP call request message and forwarded to the S-CSCF through a second target UPF.

[0106] The SIP call response message carries the IMPU of the called IMS terminal, the second IP address of the called IMS terminal, and the IMPU of the calling IMS terminal.

[0107] After receiving the SIP call request message, the called IMS terminal may generate a SIP call response message, and the generated SIP call response message may be forwarded to the S-CSCF through the second target UPF, and the S-CSCF may further forward it to the P-CSCF.

[0108] S202: According to the IMPU of the calling IMS terminal, query and obtain the first IP address of the calling IMS terminal and the third IP address of the first target UPF corresponding to the calling IMS terminal.

[0109] S203: Send the SIP call response message to the first target UPF corresponding to the third IP address, so that the first target UPF forwards the SIP call response message to the calling IMS terminal based on the first IP address.

[0110] Among them, during the transmission process of the SIP call response message, after the P-CSCF receives the SIP call response message, it can query and obtain the first IP address of the calling IMS terminal and the third IP address of the first target UPF corresponding to the calling IMS terminal according to the IMPU of the calling IMS terminal, and use the third IP address as the destination address to send the SIP call response message to the first target UPF corresponding to the calling IMS terminal. After the first target UPF receives the SIP call response message, it can forward the SIP call response message to the calling IMS terminal according to the first IP address of the calling IMS terminal, thereby realizing data communication between the calling IMS terminal and the called IMS terminal.

[0111] In summary, by using the embodiments of the present application, a voice data connection can be directly established between a calling IMS terminal and a called IMS terminal without the need for the IMS system to forward voice data and video, thereby simplifying the data forwarding process.

[0112] Figure 4 A flowchart of another IMS-based calling method provided in an embodiment of the present application. Figure 4 As shown, before the SIP call request message sent by the S-CSCF after the session management is received, the following is also included:

[0113] S301. Receive a SIP call request message sent by a first target UPF corresponding to a calling IMS terminal.

[0114] The SIP call request message is obtained by the first target UPF marking the SIP initial call request message according to its corresponding first target UPF identifier, and the SIP initial call request message is generated by the calling IMS terminal.

[0115] S302: Generate a local SIP call record according to the SIP call request message, and forward the SIP call request message to the S-CSCF so that the S-CSCF performs session management processing.

[0116] The local SIP call record includes: the IMPU of the called IMS terminal corresponding to each SIP call request message within a preset time period, the UPF identifier corresponding to the called IMS terminal, and the IP address corresponding to the called IMS terminal.

[0117] In some embodiments, after receiving the SIP call request message from the calling IMS terminal, the P-CSCF in the IMS system reads the DSCP field in the IP header of the SIP call request message, generates a local SIP call record, and forwards the SIP call request message to the S-CSCF for further session management processing, wherein the S-CSCF can be specifically used to process the logical control of the session, for example, it can decide whether to allow the call, and is responsible for correctly routing the call request to the destination, etc., which is not limited here.

[0118] Among them, the local SIP call record can be expressed in the form of<IMPU,UPF_ID,UE_IP> . Among them, IMPU is the public identifier of the calling IMS terminal, UPF_ID is the UPF identifier corresponding to the calling IMS terminal (that is, the identifier written by the calling IMS terminal UPF in the DSCP field), and UE_IP is the IP address of the calling IMS terminal. It should be noted that the calling IMS terminal can specifically be the calling IMS terminal corresponding to the SIP call request.

[0119] By applying the embodiments of the present application, it is possible to generate a local SIP record corresponding to a preset time period in the P-CSCF, so that during the call forwarding process, the P-CSCF can quickly query the second IP address of the called IMS terminal and the corresponding second target UPF identifier according to the local SIP record, thereby realizing accurate paging of the called IMS terminal.

[0120] Figure 5 A flowchart of another IMS-based calling method provided in an embodiment of the present application. Figure 5 As shown, before the above-mentioned receiving the SIP call request message sent by the first target UPF corresponding to the calling IMS terminal, it also includes:

[0121] S401. Detect the destination port number of the uplink message through the first target UPF.

[0122] S402: If it is detected that the destination port number of the uplink message is a preset port number, it is determined that the uplink message is a SIP initial call request message.

[0123] S403: Mark the SIP initial call request message through the first target UPF to obtain a SIP call request message.

[0124] The SIP initial call request message sent by the calling IMS terminal to the IMS system is forwarded by the base station and can reach its corresponding first target UPF. The first target UPF can detect the destination port number of the uplink message. If it is a preset port number (for example, 5060), it is determined that the message is a SIP initial call request message. Further, the first UPF can mark the IP message carrying the SIP initial call request message. Specifically, the first target UPF can write an identification value to the DSCP field in the IP message header to obtain the SIP call request message. The identification value is used to mark that the SIP initial call request message is forwarded by the first target UPF, and the identification value can be the identification of the first target UPF, that is, UPF_ID.

[0125] By applying the embodiments of the present application, it is possible to know the UPF corresponding to the SIP call request message through the marking operation, so that the relevant call response sent by the called IMS terminal can be forwarded to the calling IMS terminal in the future, thereby realizing accurate forwarding of the SIP call response.

[0126] In an optional implementation manner, the querying and acquiring the second IP address of the called IMS terminal and the second target UPF identifier corresponding to the called IMS terminal according to the IMPU of the called IMS terminal includes:

[0127] According to the IMPU of the called IMS terminal, the second IP address of the called IMS terminal and the second target UPF identifier corresponding to the called IMS terminal are queried from the local SIP call record or the local SIP registration record.

[0128] Optionally, in some embodiments, the second IP address of the called IMS terminal and the corresponding second target UPF identifier can be generated by querying a local SIP call record or a local SIP registration record, wherein the local SIP registration record can be generated according to a SIP registration message sent by the registered IMS terminal. It should be noted that when performing a specific query, the latest record corresponding to the called IMS terminal can be queried from the local SIP call record and the local SIP registration record according to the IMPU of the called IMS terminal, and the second IP address of the called IMS terminal and the second target UPF identifier corresponding to the called IMS terminal can be determined according to the latest record.

[0129] Figure 6 A flowchart of another IMS-based calling method provided in an embodiment of the present application. Figure 6 As shown, the above method also includes:

[0130] S601: Receive a SIP registration message sent by a third target UPF corresponding to a registered IMS terminal.

[0131] The SIP registration message is obtained by the third target UPF marking the SIP initial registration message according to its corresponding third target UPF identifier, and the SIP initial registration message is generated by the registering IMS terminal.

[0132] During the registration process, the registering IMS terminal may generate a SIP initial registration message and send it to the IMS system, and the IMS system may forward the SIP initial registration message to the UPF corresponding to the registering IMS terminal via the base station.

[0133] For the UPF corresponding to the registered IMS terminal, the UPF can detect the destination port number of the uplink message. If it is a preset port number (for example, 5060), it is determined that the message is a SIP initial registration message. Further, the UPF marks the IP message carrying the SIP initial registration message. After the marking is completed, the SIP registration message can be generated and sent to the P-CSCF.

[0134] Optionally, during specific marking, the UPF may write an identification value into the DSCP field in the IP packet header to mark the identity of the UPF in the 5G network, wherein the identification value may be the identification of the UPF corresponding to the registered IMS terminal.

[0135] S602: Forward the SIP registration message to the query call session control function I-CSCF, so as to perform terminal registration processing through the I-CSCF.

[0136] After receiving the SIP registration message, the P-CSCF may further forward it to the I-CSCF for further terminal registration processing. For example, the I-CSCF may select a suitable S-CSCF for registering the IMS terminal. This is not limited here. For the specific processing process, please refer to the relevant processing logic of the IMS system.

[0137] It should be noted that both the calling IMS terminal and the called IMS terminal need to register before making a call. For details, see Figure 6 Steps shown.

[0138] In an optional implementation manner, before forwarding the SIP registration message to the query call session control function I-CSCF, the method further includes:

[0139] A SIP registration record is generated according to the SIP registration message, where the SIP registration record includes: an IMPU of the registered IMS terminal and a third UPF identifier corresponding to the registered IMS terminal; and a local SIP registration record is updated according to the SIP registration record.

[0140] Based on the above content, it is also necessary to explain that after the P-CSCF in the IMS system receives the SIP registration message from the registered IMS terminal, it can read the DSCP field in its IP message header and generate a SIP registration record. The SIP registration record can be expressed in the form of<IMPU,UPF_ID,UE_IP> Among them, IMPU is the public identifier of the registered IMS terminal, UPF_ID is the identifier written in the DSCP field by the UPF corresponding to the registered IMS terminal, and UE_IP is the IP address of the registered IMS terminal.

[0141] Further, after the SIP registration record is obtained, the local SIP registration record in the P-CSCF may be updated so that the local SIP registration record includes the latest SIP registration record. It should be noted that, according to the actual application scenario, the local SIP registration record may include one or more SIP registration records corresponding to the registered terminals, and the number of SIP registration records in the local SIP registration record is not limited.

[0142] In an optional implementation manner, the updating of the local SIP registration record according to the SIP registration record includes:

[0143] If it is determined that the IMPU of the registered IMS terminal exists in the local SIP registration record, the local SIP registration record is updated according to the current UPF identifier corresponding to the registered IMS terminal; if it is determined that the IMPU of the registered IMS terminal does not exist in the local SIP registration record, the SIP registration record is added to the local SIP registration record.

[0144] Among them, when the IMPU of the registered IMS terminal exists in the local SIP registration record, considering that the UPF corresponding to the registered IMS terminal may change in some scenarios, then at this time, the local SIP registration record can be updated according to the current UPF identifier corresponding to the registered IMS terminal to ensure the validity of the local SIP registration record.

[0145] Of course, it should be noted that if it is determined that the IMPU of the registered IMS terminal does not exist in the local SIP registration record, the SIP registration record corresponding to the registered IMS terminal may be added to the local SIP registration record.

[0146] In summary, by applying the embodiments of the present application, flexible updating of local SIP registration records can be achieved, providing reliable guarantee for accurate paging of IMS terminals.

[0147] Figure 7A flowchart of another IMS-based calling method provided in an embodiment of the present application is provided. The method is applied to a second target user plane function UPF corresponding to the called terminal. The second target UPF is connected to the IP multimedia subsystem IMS for communication. Figure 7 As shown, the method includes:

[0148] S701. Receive a modified SIP call request message sent by a proxy call session control function P-CSCF in an IMS according to a fourth IP address of a second target UPF.

[0149] Among them, the modified SIP call request message includes the second IP address of the called IMS terminal. The modified SIP call request message is obtained by modifying the destination address of the IP packet in the SIP call request message to the second IP address. The SIP call request message is sent to the P-CSCF after session management by the service call session control function S-CSCF; the SIP call request message is marked with the corresponding first target UPF identifier by the first target UPF corresponding to the calling IMS terminal, and carries the IMPU of the calling IMS terminal, the first IP address of the calling IMS terminal, and the IMPU of the called IMS terminal; the fourth IP address of the second target UPF is obtained by the P-CSCF based on the second target UPF identifier corresponding to the called IMS terminal, the second IP address of the called IMS terminal and the second target UPF identifier corresponding to the called IMS terminal are obtained by the P-CSCF based on the IMPU of the called IMS terminal, and the IMPU of the called IMS terminal is obtained by the P-CSCF based on the SIP call request message.

[0150] S702: Forward the modified SIP message in the SIP call request message to the called IMS terminal based on the second IP address of the called IMS terminal.

[0151] Combined with the above Figure 1 The steps shown, wherein, after the P-CSCF retrieves and obtains the fourth IP address of the second target UPF corresponding to the called IMS terminal, the fourth IP address can be used as the destination address, and the SIP call request message can be encapsulated into a GRE tunnel message, and the message is sent to the local area network; after the second target UPF receives the GRE tunnel message from the local area network, the IP message can be extracted therein and forwarded to the called IMS terminal, so that the IMS system can accurately forward the SIP call request message initiated by the calling IMS terminal to the called IMS terminal when multiple UPFs are connected, without introducing a complex routing update mechanism in the local area network, and the implementation of the method of the present application does not require modification of the IMS terminal, and is easy to implement.

[0152] Figure 8A communication interaction diagram of a calling method based on an IMS system provided in an embodiment of the present application, Fig. 9 A communication interaction diagram of a calling method based on an IMS system provided in an embodiment of the present application. Figure 8 and Fig. 9 As shown, the method includes:

[0153] S801: The calling IMS terminal generates a SIP initial call request message and sends it to a first target UPF.

[0154] S802. The first target UPF corresponding to the calling IMS terminal detects the destination port number of the uplink message. If the destination port number of the uplink message is detected to be a preset port number, the uplink message is determined to be a SIP initial call request message, and the SIP initial call request message is marked to obtain a SIP call request message.

[0155] The SIP call request message is marked with a first target UPF identifier, and carries the IMPU of the calling IMS terminal, the first IP address of the calling IMS terminal, and the IMPU of the called IMS terminal.

[0156] S803. The first target UPF forwards the SIP call request message to the P-CSCF.

[0157] S804. The P-CSCF receives the SIP call request message sent by the first target UPF, and generates a local SIP call record according to the SIP call request message.

[0158] S805. The P-CSCF forwards the SIP call request message to the S-CSCF.

[0159] S806. The S-CSCF receives the SIP call request message, and forwards the SIP call request message to the P-CSCF after performing session management processing.

[0160] S807. The P-CSCF receives the SIP call request message sent by the S-CSCF after performing session management, and obtains the IP Multimedia Private User Identity IMPU of the called IMS terminal according to the SIP call request message.

[0161] S808. The P-CSCF queries and obtains the second IP address of the called IMS terminal and the second target UPF identifier corresponding to the called IMS terminal according to the IMPU of the called IMS terminal. According to the second IP address, the destination address of the IP packet in the SIP call request message is modified to the second IP address, and according to the second target UPF identifier, queries and obtains the fourth IP address of the second target UPF.

[0162] S809. The P-CSCF sends the SIP call request message to the second target UPF corresponding to the fourth IP address.

[0163] S810. The second target UPF forwards the SIP message in the modified SIP call request message to the called IMS terminal based on the second IP address.

[0164] S811. The called IMS terminal generates a SIP call response message according to the SIP call request message, and forwards it to the P-CSCF through the second target UPF.

[0165] The SIP call response message carries the IMPU of the called IMS terminal, the second IP address of the called IMS terminal, and the IMPU of the calling IMS terminal.

[0166] S812. The P-CSCF forwards a SIP call response message to the S-CSCF. The SIP call response message carries the IMPU of the called IMS terminal, the second IP address of the called IMS terminal, and the IMPU of the calling IMS terminal.

[0167] S813. The S-CSCF receives the SIP call response message, and forwards the SIP call response message to the P-CSCF after performing session management processing.

[0168] S814. The P-CSCF queries and obtains the first IP address of the calling IMS terminal and the third IP address of the first target UPF corresponding to the calling IMS terminal according to the IMPU of the calling IMS terminal in the SIP call response message.

[0169] S815. The P-CSCF sends the SIP call response message to the first target UPF corresponding to the third IP address.

[0170] S816. The first target UPF forwards the SIP call response message to the calling IMS terminal based on the first IP address.

[0171] S817: The calling IMS terminal receives the SIP call response message forwarded by the first target UPF.

[0172] Combination Figure 8 and Fig. 9It can be seen from the steps shown that after receiving the SIP message from the IMS terminal, the UPF marks its IP message header and sends it to the IMS system. After receiving the SIP message, the IMS system reads the marked message in the IP message header and records the specific UPF information of the IMS terminal connection. Furthermore, when the IMS system receives a call request for the terminal, it forwards it to the corresponding UPF according to the pre-recorded marked information, which can simplify the user call request processing process and support the IMS system to accurately page the target user among multiple UPFs without introducing a complex routing update mechanism in the local area network. The implementation of this solution does not require modification of the IMS terminal, but only requires simple changes to the UPF and P-CSCF to achieve accurate paging of the IMS terminal. Furthermore, this solution supports the direct establishment of a voice data connection between the calling IMS terminal and the called IMS terminal without the need for the IMS system to forward voice data, simplifying the data forwarding process.

[0173] Fig. 9 This is a functional module diagram of a call device based on an IMS system provided in an embodiment of the present application. The call device can be integrated into the aforementioned P-CSCF. The basic principle and technical effects of the device are the same as those of the aforementioned corresponding method embodiment. For the sake of brief description, the parts not mentioned in this embodiment can be referred to the corresponding contents in the method embodiment. Fig. 9 As shown, the calling device 100 may include:

[0174] The receiving module 110 is used to receive a session initiation protocol SIP call request message sent by the service call session control function S-CSCF after performing session management, and obtain the IP multimedia private user identity IMPU of the called IMS terminal according to the SIP call request message, wherein the SIP call request message is marked with the first target UPF corresponding to the calling IMS terminal and carries the IMPU of the calling IMS terminal, the first IP address of the calling IMS terminal, and the IMPU of the called IMS terminal;

[0175] A query module 120, configured to query and obtain, according to the IMPU of the called IMS terminal, a second IP address of the called IMS terminal and a second target UPF identifier corresponding to the called IMS terminal;

[0176] The acquisition module 130 is used to modify the destination address of the IP packet in the SIP call request message to the second IP address according to the second IP address, and query and obtain the fourth IP address of the second target UPF according to the second target UPF identifier;

[0177] The sending module 140 is used to send the SIP call request message to the second target UPF corresponding to the fourth IP address, so that the second target UPF forwards the SIP message in the modified SIP call request message to the called IMS terminal based on the second IP address.

[0178] Optionally, the embodiment of the present application further provides a calling device, which can be integrated into the aforementioned UPF. The basic principle and technical effects of the calling device are the same as those of the aforementioned corresponding method embodiment. For the sake of brief description, the parts not mentioned in this embodiment can refer to the corresponding contents in the method embodiment. The calling device 100 may include:

[0179] The receiving module is used to receive the modified SIP call request message sent by the proxy call session control function P-CSCF in the IMS according to the fourth IP address of the second target UPF.

[0180] Among them, the modified SIP call request message includes the second IP address of the called IMS terminal. The modified SIP call request message is obtained by modifying the destination address of the IP packet in the SIP call request message to the second IP address. The SIP call request message is sent to the P-CSCF after session management by the service call session control function S-CSCF; the SIP call request message is marked with the corresponding first target UPF identifier by the first target UPF corresponding to the calling IMS terminal, and carries the IMPU of the calling IMS terminal, the first IP address of the calling IMS terminal, and the IMPU of the called IMS terminal; the fourth IP address of the second target UPF is obtained by the P-CSCF based on the second target UPF identifier corresponding to the called IMS terminal, the second IP address of the called IMS terminal and the second target UPF identifier corresponding to the called IMS terminal are obtained by the P-CSCF based on the IMPU of the called IMS terminal, and the IMPU of the called IMS terminal is obtained by the P-CSCF based on the SIP call request message.

[0181] The forwarding module is used to forward the SIP message in the modified SIP call request message to the called IMS terminal based on the second IP address of the called IMS terminal.

[0182] The above-mentioned device is used to execute the method provided by the aforementioned embodiment, and its implementation principle and technical effect are similar, which will not be repeated here.

[0183] The above modules 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, or one or more field programmable gate arrays (FPGAs). For another example, when a module is implemented in the form of a processing element scheduling program code, the processing element may be a general-purpose processor, such as a central processing unit (CPU) or other processor that can call program code. For another example, these modules may be integrated together and implemented in the form of a system-on-a-chip (SOC).

[0184] Fig.10 The following is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may be the P-CSCF or UPF mentioned above. Fig.10 As shown, the electronic device may include: a processor 210, a storage medium 220 and a bus 230, the storage medium 220 stores machine-readable instructions executable by the processor 210, when the electronic device is running, the processor 210 and the storage medium 220 communicate through the bus 230, and the processor 210 executes the machine-readable instructions to perform the steps of the above method embodiment. The specific implementation method and technical effect are similar and will not be repeated here.

[0185] Optionally, the present application further provides a storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above method embodiment are executed. The specific implementation method and technical effect are similar and will not be repeated here.

[0186] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0187] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0188] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0189] The above-mentioned integrated unit implemented in the form of a software functional unit can be stored in a computer-readable storage medium. The above-mentioned software functional unit is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (English: processor) to perform some steps of the methods of each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (English: Read-Only Memory, abbreviated: ROM), random access memory (English: Random Access Memory, abbreviated: RAM), disk or optical disk and other media that can store program codes.

[0190] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0191] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A calling method based on an IMS system, characterized in that: A proxy call session control function P-CSCF is applied to an IP multimedia subsystem IMS, wherein the IMS system is communicatively connected with a plurality of user plane functions UPF, and the method comprises: Receiving a session initiation protocol SIP call request message sent by a service call session control function S-CSCF after performing session management, and acquiring an IP multimedia private user identity IMPU of the called IMS terminal according to the SIP call request message, wherein the SIP call request message is marked with its corresponding first target UPF identity by the first target UPF corresponding to the calling IMS terminal, and carries the IMPU of the calling IMS terminal, the first IP address of the calling IMS terminal, and the IMPU of the called IMS terminal; According to the IMPU of the called IMS terminal, query and obtain the second IP address of the called IMS terminal and the second target UPF identifier corresponding to the called IMS terminal; According to the second IP address, modify the destination address of the IP packet in the SIP call request message to the second IP address, and query and obtain the fourth IP address of the second target UPF according to the second target UPF identifier; The SIP call request message is sent to the second target UPF corresponding to the fourth IP address, so that the second target UPF forwards the SIP message in the modified SIP call request message to the called IMS terminal.

2. The method according to claim 1, characterized in that The method further comprises: receiving a SIP call response message forwarded by the S-CSCF, where the SIP call response message is generated by the called IMS terminal according to the SIP call request message and forwarded to the S-CSCF through the second target UPF, and the SIP call response message carries the IMPU of the called IMS terminal, the second IP address of the called IMS terminal, and the IMPU of the calling IMS terminal; According to the IMPU of the calling IMS terminal, query and obtain the first IP address of the calling IMS terminal and the third IP address of the first target UPF corresponding to the calling IMS terminal; The SIP call response message is sent to the first target UPF corresponding to the third IP address, so that the first target UPF forwards the SIP call response message to the calling IMS terminal based on the first IP address.

3. The method according to claim 1, characterized in that Before receiving the SIP call request message sent by the S-CSCF after performing session management, the method further includes: receiving a SIP call request message sent by a first target UPF corresponding to the calling IMS terminal, wherein the SIP call request message is obtained by marking a SIP initial call request message by the first target UPF according to its corresponding first target UPF identifier, and the SIP initial call request message is generated by the calling IMS terminal; Generate a local SIP call record according to the SIP call request message, and forward the SIP call request message to the S-CSCF, so that the S-CSCF performs session management processing, wherein the local SIP call record includes: the IMPU of the calling IMS terminal corresponding to each SIP call request message within a preset time period, the UPF identifier corresponding to the calling IMS terminal, and the IP address corresponding to the calling IMS terminal.

4. The method according to claim 3, characterized in that Before receiving the SIP call request message sent by the first target UPF corresponding to the calling IMS terminal, the method further includes: Detecting the destination port number of the uplink message through the first target UPF; If it is detected that the destination port number of the uplink message is a preset port number, determining that the uplink message is a SIP initial call request message; The SIP call request message is obtained by marking the SIP initial call request message through the first target UPF.

5. The method according to claim 3, characterized in that: The querying and acquiring the second IP address of the called IMS terminal and the second target UPF identifier corresponding to the called IMS terminal according to the IMPU of the called IMS terminal includes: According to the IMPU of the called IMS terminal, the second IP address of the called IMS terminal and the second target UPF identifier corresponding to the called IMS terminal are queried and acquired from the local SIP call record or the local SIP registration record.

6. The method according to claim 1, characterized in that The method further comprises: Receive a SIP registration message sent by a third target UPF corresponding to the registered IMS terminal, where the SIP registration message is obtained by the third target UPF marking a SIP initial registration message according to its corresponding third target UPF identifier, and the SIP initial registration message is generated by the registered IMS terminal; The SIP registration message is forwarded to an inquiry call session control function I-CSCF, so that the terminal registration process is performed through the I-CSCF.

7. The method according to claim 6, characterized in that Before forwarding the SIP registration message to the query call session control function I-CSCF, the method further includes: Generate a SIP registration record according to the SIP registration message, wherein the SIP registration record includes: an IMPU of the registered IMS terminal and a UPF identifier corresponding to the registered IMS terminal; According to the SIP registration record, the local SIP registration record is updated.

8. The method according to claim 7, characterized in that The updating of the local SIP registration record according to the SIP registration record includes: If it is determined that the IMPU of the registered IMS terminal exists in the local SIP registration record, updating the local SIP registration record according to the current UPF identifier corresponding to the registered IMS terminal; If it is determined that the IMPU of the registered IMS terminal does not exist in the local SIP registration record, the SIP registration record is added to the local SIP registration record.

9. A calling method based on an IMS system, characterized in that: The method is applied to a second target user plane function UPF corresponding to the called terminal, the second target UPF being communicatively connected to the IP multimedia subsystem IMS, and comprising: Receive a modified SIP call request message sent by a proxy call session control function P-CSCF in the IMS according to the fourth IP address of the second target UPF; wherein the modified SIP call request message is obtained by modifying the destination address of the IP packet in the SIP call request message to the second IP address of the called IMS terminal, and the SIP call request message is sent to the P-CSCF after session management by the service call session control function S-CSCF; the SIP call request message is marked with the first target UPF identifier corresponding to the calling IMS terminal by the first target UPF corresponding to the calling IMS terminal, and carries the IMPU of the calling IMS terminal, the first IP address of the calling IMS terminal, and the IMPU of the called IMS terminal; the fourth IP address of the second target UPF is obtained by the P-CSCF according to the second target UPF identifier corresponding to the called IMS terminal, the second IP address of the called IMS terminal and the second target UPF identifier corresponding to the called IMS terminal are obtained by the P-CSCF according to the IMPU of the called IMS terminal, and the IMPU of the called IMS terminal is obtained by the P-CSCF according to the SIP call request message; The SIP message in the modified SIP call request message is forwarded to the called IMS terminal.

10. An electronic device, characterized in that: include: A processor, a storage medium and a bus, wherein the storage medium stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor and the storage medium communicate through the bus, and the processor executes the machine-readable instructions to perform the steps of the calling method based on the IMS system as claimed in any one of claims 1 to 9.

Images