CN106790055A - A kind of register method and device of IMS systems - Google Patents

Abstract

A registration method and device for an IMS system. The device includes user equipment UE, sending unit, receiving unit, authentication unit and registration unit; the present invention is different from the original IMS registration method. In the present invention, when a registration event occurs, the network equipment needs a Access certificate, which can reduce the pressure on the server. These certificates are generated through a network device or an interface not shown in the figure. When a self-defined condition is met, the network device sends a notification to the enabler, and the enabler then notifies the user. Because it is connected to P-CSCF, S-CSCF and HSS, the network device we invented looks more like a user. The network device is connected to the P-CSCF through the interface Gm, and the SIP protocol in this interface can be used to transfer information between the user equipment and the session control function server.

Description

A registration method and device for an IMS system

technical field

The invention belongs to the technical field of IP multimedia subsystems, and in particular relates to a registration method and device of an IMS system.

Background technique

IMS (IP Multimedia Subsystem) is a fusion of multiple cellular network technologies that enables people anywhere to conduct instant messaging, participate in video conferences, and send e-mails. IMS is a core element of the third generation network framework, which can provide most Internet services. For example, it enables a person to use any terminal device to log in his favorite web pages, read emails, watch movies or participate in video conferences.

With the integration of packet switching technology and circuit switching technology becoming the trend, the main goal of IMS is to use this technology to connect mobile devices to the Internet. Its other goal is to create a platform that can provide a variety of multimedia services and expand the service range of packet switching network technology for mobile phones. IMS includes various multimedia service protocols, such as session control protocol and session initiation protocol (SIP). The IMS framework is a collection of standardized interfaces containing various functions.

FIG. 1A is a basic framework diagram of an existing IMS. This is a set of currently most popular standards proposed by 3GPP, which describes the global mobile communication system in detail. In the figure, an IMS mobile terminal 140 communicates using a wireless base station 138 in a packet network 136 such as GPRS. The figure also shows some other key nodes of the IMS network. These nodes include one or more Subscriber Database (HSS) 120 and Subscriber Location Function Server SLFS 122 called Home Subscriber Servers. Also shown are SIP servers 116, 118 using the Subscriber Session Control Protocol (CSCFS). There are also multiple SIP application servers 108 in the figure. 126 and 128 are media resource function processors MRF, and MRF is composed of MRFCs126 and MRFPs128, respectively representing media resource controllers and media resource processors. Breakout Gateway Control Functions (BGCFs) 124 are essentially a SIP server that performs routing by telephone number and controls calls to and from the Public Switched Telephone Network (PSTN). The BGCF mainly implements the call routing function, and is used to select the network connected to the PSTN/CS domain entry point, receive the request of the S-CSCF, and select an appropriate PSTN interface point for the next call. In FIG. 1A , the PSTN gateway is composed of a signaling gateway (SGW) 130 , a media gateway controller (MGCF) 132 and a media gateway (MGW) 134 . The HSS includes service data of all registered users, including the user's location information, security information, user authorization information, and user authentication information of the IMS. The SIP server that implements the user session control function is a relatively important node in the IMS, and it is used to process SIP signaling. As shown in Figure 1A, CSCFs can be divided into three types according to their functions. P-CSCF106A is the unified entry point for IMS to access the network. All session messages originating from and terminating from the IMS terminal must pass through the P-CSCF. From the point of view of SIP protocol, P-CSCF 106A, 106B can be regarded as a SIP proxy server, which means that all session messages initiated by IMS terminal 140, 102 and terminated by IMS terminal must pass through P-CSCF. The P-CSCF forwards the SIP request and forwards the response to the appropriate user equipment 140, 102 or IMS network. During the user registration process, the IMS terminal only communicates with the same P-CCSCF, so when a registration request is initiated, the P-CSCF will only be assigned to one IMS terminal, and will not change during the registration process. P-CSCF includes many functions to ensure security. For example, it will establish a large number of Internet Security Protocols (IPsec) for security association with IMS terminals. These IPsec are used to ensure that messages will not change after they are created. Once the P-CSCF authorizes the user, the P-CSCF confirms the user's identity in the remaining network nodes, so that other network nodes do not need to continue to confirm the user, so that they can continue to provide users with personal services and generate user account information. The P-CSCF is also used to judge the correctness of the SIP request sent by the IMS terminal to prevent the IMS terminal from generating requests that do not conform to the rules of the SIP protocol. Each P-CSCF can serve multiple IMS terminals, of course, the number of IMS terminals must be within a certain limit.

The IMS network also uses the I-CSCF (118), which is a SIP proxy server, usually located at the edge of the administrative domain. The S-CSCF (116) is at the core of the IMS network session control, it is the central node of signaling, and it is essentially a SIP server. S-CSCF also exhibits a certain control function, because it can also be used as a SIP registrar, maintaining the connection between the user's IP address and the SIP address (PUID). During the registration process, the I-CSCF selects an S-CSCF for the user by querying the HSS. During the call process, the call to the IMS network is first routed to the I-CSCF, and the I-CSCF obtains the S-CSCF address registered by the user from the HSS, and then routes the message to the S-CSCF. The S-CSCF accepts the registration request forwarded from the P-CSCF, cooperates with the HSS to perform user authentication, and downloads the service data of the subscriber from the HSS. The S-CSCF performs routing management on the user's active call or called, and triggers the SIP application server according to the initial filter rule (iFC) of the subscriber to realize rich IMS service functions.

SIP-AS is a local application server used to implement IP multimedia services based on SIP protocol. OSA-SCS110 is a service capability application server, which connects with network devices through OSA API interface. OSA-SCS inherits most of the capabilities of OSA, especially the ability to connect to the IMS network from the external network. On the one hand, it acts as an application server, and on the other hand, it can be used as an interface between OSA and external applications. IM-SSF (118) is a special application server, which utilizes a mobile terminal application to enhance GSM in IMS.

The SGW signaling gateway is connected to the No.7 signaling network and interconnected with the IP network. It mainly completes the conversion function of the No.7 signaling on the PSTN/ISDN side and the IP side signaling. The SGW is responsible for protocol conversion between layers, for example, converting the low-layer MTP protocol into the SCTP protocol. The media gateway controller MGCF is the central node of the PSTN gateway. It uses a state transition machine for protocol conversion and communicates with various media gateways, terminals and networks using a variety of protocols, including SIP, ISUP and VICC. The media gateway MGW is a unit connecting different types of networks, and performs conversion between disparate networks such as PSTN. On the other hand, MGW can send or receive video in IMS through RTP (Real-time Transport Protocol). When the IMS terminal does not support the SCI code, the MGW can also be used for code conversion.

The following is a detailed introduction to the process of users accessing the IMS system. Since some current IMS registration methods have great defects, relevant supplements are made. The IMS registration process is as follows:

Step 1, the user equipment UE must generate an IMS entity when sending a registration request, this step is called the proxy call control stage.

Step 2, before the registration process, the user equipment UE needs to obtain a user entity from the entity set. An S-CSCF is assigned to user equipment and is authorized to form corresponding security associations.

Step 3: A user file is downloaded from the HSS to the S-CSCF. During this process, the SIP protocol is initialized and secretly transmits the public user identifier PUID. IMS registration includes two phases. The first phase mainly includes how the IMS network sends a request to the user equipment, and the second phase describes how the user equipment responds to the network request and completes the entire registration process.

Step 4, the user equipment 140, 102 sends a SIP request to the P-CSCF 106A, 106B, and the request may include an information entity representing the cell name and the user address.

Step 5, the P-CSCF now starts to process the registration request, and resolves the IP address of the I-CSCF 118 according to the cell name provided. The I-CSCF gets in touch with the HSS 120 accordingly, and analyzes the maximum capacity that the HSS can select for the S-CSCF 116 .

Step 6: After the HSS selects the S-CSCF, the I-CSCF forwards the registration request to the S-CSCF. If the S-CSCF finds that the user is not authorized, it extracts the authorization information from the HSS and sends it to the user "401" The response means that the user has not been authorized.

Step 7, when the user equipment starts to analyze the first request, the P-CSCF receives the second request at this time, and then continues to repeat the process of the first step. After the S-CSCF receives the response, if the information is true, It will download user information from HSS, and send a "200" message to indicate that the request is successful.

Step 8, once the user equipment is successfully authorized, it can initialize and receive messages. One of the responsibilities of the user equipment is to continuously update the registration information. If the user equipment does not update the registration information, the S-CSCF will regard this registration as a mistake and remove it. When the user equipment logs out from the IMS, it records the registration timer as 0 and sends a registered information.

To sum up, there are still some problems in the above-mentioned basic IMS access. First, all registration and deregistration must be performed in a fixed user device address, which will cause some problems, such as problems caused by the aging of the user device, which will cause the registration to fail or the registration to be interrupted during the interaction process. The application of the user's private id in the authorization process brings about the problem of service portability. The user's private id is associated with the device and the user. This method has a good effect on one-to-one operations, such as mobile phones and so on. However, for one-to-many operations, that is, there is only one device but the registration process of multiple users. For example, in an office fixed-line network, different fixed-line phones need to make temporary calls at different times. The existing IMS access process There is no such function.

Contents of the invention

In order to solve the above problems, the object of the present invention is to provide a registration method and device for an IMS system.

In order to achieve the above object, the registration method of the IMS system provided by the present invention includes the following steps in order:

Step 1. The user equipment UE sends a SIP registration request to the P-CSCF, and this request includes a user identifier to be registered;

Step 2. The P-CSCF processes the registration request and sends the request to the I-CSCF;

Step 3. Before the I-CSCF queries the S-CSCF address from the HSS, it will send the registration request to the registration manager; after the network device receives the notification, the user can enter its user information on the web page to register; the network device As a registration agent, forward the registration message to S-CSCF and HSS, and assign a private user ID to the user;

Step 4. After that, the I-CSCF will send a Cx interface query message to the HSS to query the address of the S-CSCF;

Step 5. After the HSS selects the S-CSCF, the address of the S-CSCF is directly sent to the I-CSCF through the Cx interface query response message;

Step 6. After determining the address of the S-CSCF, the I-CSCF will forward the SIP registration request to the S-CSCF, and the S-CSCF will send the Cx interface user authentication information from the HSS;

Step 7, the HSS returns the authentication information obtained through the authentication to the S-CSCF through the Cx interface authentication response information;

Step 8. If the S-CSCF finds that the user is not authorized, it extracts the authorization information from the HSS, and sends a response of "401" to the user, which means that the user has not been authorized;

Step 9. When the user equipment starts to parse the first request, the P-CSCF receives the second request at this time, and then repeats the process of the previous steps;

Step 10. After the S-CSCF receives the response, if the information is true, it will download the user information from the HSS, and send a "200" message to indicate that the request is successful;

Step 11, S-CSCF uses the header file or the public user identifier PUID in the IMS message to select a service framework in the user configuration file to generate the initial service; once the user equipment is authorized successfully, it can initialize and receive the message;

Step 12, when the user equipment is deregistered from the IMS, the registration timer is recorded as 0 and a registered information is sent;

Step 13. After the registration is successful, the user equipment will receive a message "200 OK" from the S-CSCF, indicating that the entire registration process has been completed; if a user has not registered before, then its public user identification PUID does not currently exist, S-CSCF will process this registration through HSS and assign a public user identification PUID to the user. If the user has registered before, just select a public user identification PUID from S-CSCF to associate with the current user.

The IMS system registration device using the above method provided by the present invention includes: user equipment UE, a sending unit, a receiving unit, an authentication unit and a registration unit; wherein,

User equipment UE: mainly used as terminal equipment for accessing the IMS system, using wireless equipment or hardware access equipment;

Sending unit: used to send the registration message directly to the S-CSCF according to the S-CSCF address; at this time, the registration message will include the public user identifier PUID, and will continue to send a "200" response after the authentication is successful; When the authentication unit authenticates successfully, it sends a Cx interface push or Cx interface pop message to the HSS;

Receiving unit: used to receive the public user identifier PUID assigned to the user equipment UE by each service access point, and receive the P-CSCF discovery list fed back by the access point corresponding to each service; the receiving unit is also used to receive the authentication When the authorization unit is successful, the Cx interface response returned when sending the Cx interface authentication information to the HSS;

Registration management unit: this unit is the registration manager, which can act as a proxy for the registration and cancellation of the public user identification PUID from the server; a registration notification sent from the enabler represents the beginning of the entire registration, and the user can enter his/her name on the web page User information is registered; the registration manager, as a registration agent, forwards the registration message to S-CSCF and HSS, and they will assign a private user ID to the user and authorize it;

Authentication unit: used for authenticating the user equipment UE, and judging whether to grant the user registration authority;

Registration unit: when the authentication is successful, that is, when the user equipment UE receives a response of "200", the IMS system performs an initial registration process in this unit.

The registration method and device of the IMS system provided by the present invention are different from the original IMS registration method. In the present invention, when a registration event occurs, the network equipment needs an access certificate for each user, which can reduce the pressure on the server . These certificates are generated through a network device or an interface not shown in the figure. When a self-defined condition is met, the network device sends a notification to the enabler, and the enabler then notifies the user. Because it is connected with P-CSCF, S-CSCF and HSS, the network device we invented looks more like a user. The network equipment is connected to the P-CSCF through the interface Gm, and the SIP protocol in this interface can be used to transfer information between the user equipment and the session control function server.

Description of drawings

FIG. 1A is a basic frame structure diagram of an IMS system in the prior art.

FIG. 1B is a structural diagram of the basic framework of the IMS system provided by the present invention.

FIG. 2 is a flowchart of an IMS system access method on the P-CSCF side in the prior art;

FIG. 3 is a flowchart of an IMS system access method on the S-CSCF side in the prior art;

Fig. 4 is the flow chart of the registration method of the IMS system provided by the present invention;

FIG. 5 is a schematic structural diagram of a registration device of the IMS system provided by the present invention;

detailed description

Below we discuss various implementations of the present invention in detail, and FIG. 1B is a basic framework diagram of the IMS system provided by the present invention. A general IMS architecture includes three layers: transfer layer, network layer, and application layer. The registration manager proposed by the present invention is in the application layer, and the general framework includes two terminals 152 and 153 registered with P-CSCF (150A 150B). P-CSCF represents the function of the proxy call control stage, which can be used as a SIP server or proxy to generate signals in the IMS system. Therefore, the two SIP proxies 150A and 150B are the first communication nodes between the IMS system and the user terminal. As a proxy server, the P-CSCF can be deployed on the public network, or it can also be deployed on the home network when the public network cannot be accessed. The user terminal is connected to the P-CSCF through the Dynamic Host Assignment Protocol (DHCP) or the General Packet Radio Service (GPRS). P-CSCF can also perform registration communication with S-CSCF (158). S-CSCF is a control node at the application layer, and it is also a SIP server, but its main function is session control. It is deployed in the home network and connected to the home subscriber server HSS 160 through the Cx interface or the Dx interface, and is used for downloading or uploading user files. The S-CSCF also has some other functions, such as processing SIP registration, binding the user's address and its own SIP address, checking each message and deciding which application server to forward the SIP message to (162 164 166). 170 in the figure represents Registration Interface Management (IRM), which provides registration information to P-CSCF and S-CSCF.

As shown in Figure 1B, there are some other interfaces connected to the IRM. First, a user network device 174 (either wired or wireless) or other communication port is connected to the IRM through the network interface 172 . 176 in the figure represents an enabler, which is actually a piece of software that can access various applications through corresponding interfaces, and each application can obtain information from the enabler. For example, a user can obtain notification information from a network device through an enabler, and any message available to a user can be obtained through the enabler. Application server 162 through interface 163 can also change the registration behavior as shown in the figure.

Different from the original IMS registration, in the present invention, when a registration event occurs, the network device needs an access certificate for each user, which can reduce the pressure on the server. These certificates are generated through a network device or an interface not shown in the figure. When a self-defined condition is met, the network device sends a notification to the enabler, and the enabler then notifies the user. Because it is connected with P-CSCF, S-CSCF and HSS, the network equipment of the present invention looks more like a user. The network equipment is connected to the P-CSCF through the interface Gm, and the SIP protocol in this interface can be used to transfer information between the user equipment and the session control function server. 178 in the figure represents the serving gateway SGW. 180 in the figure is an interface between the enabler and the user equipment, and this interface operates through the IMS system protocol or related communication mechanisms.

Although the technical solution proposed by the embodiment of the present invention will increase the registration time to a certain extent, it enables the user to obtain greater decision-making power on the basis of sacrificing the registration time, and the user can freely choose the logout time through the registration manager , when the "move" command is entered in the registration manager, it is also possible to register at one location and log out at a different location, thereby making the IMS registration process more convenient.

The technical solutions provided by the embodiments of the present invention will be described below in conjunction with the accompanying drawings.

Referring to Fig. 2, a kind of IP Multimedia Subsystem IMS registration method provided by the embodiment of the present invention, after the P-CSCF receives the registration message that contains the unauthorized response sent by the user equipment UE, the method includes:

201. The P-CSCF determines the address of the I-CSCF;

202. After determining the address of the I-CSCF, forward the registration message to the registration manager, and after the user packages the registration information through setting the registration manager, forward the registration information to the I-CSCF;

203. The I-CSCF uses the HSS to query the address of the S-CSCF.

Correspondingly, on the S-CSCF side, referring to FIG. 3 , an IP Multimedia Subsystem IMS registration method provided by an embodiment of the present invention includes:

301. The S-CSCF requests the HSS to download a user authentication vector according to the public user identifier of the user equipment included in the registration request;

302. The HSS generates the user authentication vector according to the public user identity of the user equipment, and feeds it back to the S-CSCF;

303. After receiving the user authentication vector, the S-CSCF returns an authentication challenge to the user equipment through the I-CSCF and the P-CSCF.

As shown in Figure 4, the registration method of the IMS system provided by the present invention includes the following steps in order:

Step 1. The user equipment UE sends a SIP registration request to the P-CSCF, and this request includes a user identifier to be registered;

Step 2. The P-CSCF processes the registration request and sends the request to the I-CSCF;

Step 3. Before the I-CSCF inquires the address of the S-CSCF from the HSS, it will send the registration request to the registration manager; the registration manager is a network interface, and its role is to act as an agent for all registrations and cancellations. The network device can act as a proxy for the registration and deregistration of the public user identification PUID from the server. A registration notification sent from the enabler represents the beginning of the entire registration. After the network device receives the notification, the user can enter his user information on the web page to register. The network device acts as a registration agent, forwards the registration message to the S-CSCF and HSS, and assigns a private user ID to the user;

Step 4. After that, the I-CSCF will send a Cx interface query message to the HSS to query the address of the S-CSCF;

Step 5. After the HSS selects the S-CSCF, the address of the S-CSCF is directly sent to the I-CSCF through the Cx interface query response message. This step does not need to go through the registration manager;

Step 6. After determining the address of the S-CSCF, the I-CSCF will forward the SIP registration request to the S-CSCF, and the S-CSCF will send the Cx interface user authentication information from the HSS;

Step 7, the HSS returns the authentication information obtained through the authentication to the S-CSCF through the Cx interface authentication response information;

Step 8. If the S-CSCF finds that the user is not authorized, it extracts the authorization information from the HSS, and sends a response of "401" to the user, which means that the user has not been authorized;

Step 9. When the user equipment starts to parse the first request, the P-CSCF receives the second request at this time, and then repeats the process of the previous steps;

Step 10. After the S-CSCF receives the response, if the information is true, it will download the user information from the HSS, and send a "200" message to indicate that the request is successful;

Step 11, S-CSCF uses the public user identification PUID in the header file or IMS message to select a service framework in the user configuration file to generate the initial service; once the user equipment is authorized successfully, it can initialize and accept the message; the user equipment's One of the responsibilities is to continuously update the registration information. If the user equipment does not update the registration information, the S-CSCF will regard this registration as a mistake and remove it;

Step 12, when the user equipment logs out from the IMS, it records the registration timer as 0 and sends a registered information.

Step 13. After the registration is successful, the user equipment will receive a message "200 OK" from the S-CSCF, indicating that the entire registration process has been completed; if a user has not registered before, then its public user identification PUID does not currently exist, S-CSCF will process this registration through HSS and assign a public user identification PUID to the user. If the user has registered before, just select a public user identification PUID from S-CSCF to associate with the current user.

As shown in Figure 5, on the P-CSCF side, the IMS system registration device provided by the present invention includes: user equipment UE, a sending unit, a receiving unit, an authentication unit and a registration unit; wherein,

User equipment UE: It is mainly used as a terminal device for accessing the IMS system, using wireless devices such as mobile phones, or using hardware access devices such as laptop computers and desktop computers.

Sending unit: used to send the registration message directly to the S-CSCF according to the address of the S-CSCF. At this time, the registration message will contain the public user identifier PUID, and after the authentication is successful, it will continue to send a "200" response. When the authentication unit authenticates successfully, it sends a Cx interface push or Cx interface pop message to the HSS;

Receiving unit: used to receive the public user identifier PUID assigned to the user equipment UE by each service access point, and receive the P-CSCF discovery list fed back by the access point corresponding to each service; the receiving unit is also used to receive the authentication When the authorization unit succeeds, send the Cx interface response returned when the Cx interface authentication information is sent to the HSS.

Registration management unit: this unit is the registration manager, which can act as a proxy for the registration and cancellation of the public user identification PUID from the server; a registration notification sent from the enabler represents the beginning of the entire registration, and the user can enter his/her name on the web page User information is registered; the registration manager, as a registration agent, forwards the registration message to S-CSCF and HSS, and they will assign a private user ID to the user and authorize it;

Authentication unit: used for authenticating the user equipment UE, and judging whether to grant the user registration authority;

Registration unit: when the authentication is successful, that is, when the user equipment UE receives a response of "200", the IMS system performs an initial registration process in this unit.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (2)

1. A registration method for an IMS system, characterized in that: the registration method for the IMS system includes the following steps in order: Step 1. The user equipment UE sends a SIP registration request to the P-CSCF, and this request includes a user identifier to be registered; Step 2. The P-CSCF processes the registration request and sends the request to the I-CSCF; Step 3. Before the I-CSCF queries the S-CSCF address from the HSS, it will send the registration request to the registration manager; after the network device receives the notification, the user can enter its user information on the web page to register; the network device As a registration agent, forward the registration message to S-CSCF and HSS, and assign a private user ID to the user; Step 4. After that, the I-CSCF will send a Cx interface query message to the HSS to query the address of the S-CSCF; Step 5. After the HSS selects the S-CSCF, the address of the S-CSCF is directly sent to the I-CSCF through the Cx interface query response message; Step 6. After determining the address of the S-CSCF, the I-CSCF will forward the SIP registration request to the S-CSCF, and the S-CSCF will send the Cx interface user authentication information from the HSS; Step 7, the HSS returns the authentication information obtained through the authentication to the S-CSCF through the Cx interface authentication response information; Step 8. If the S-CSCF finds that the user is not authorized, it extracts the authorization information from the HSS, and sends a response of "401" to the user, which means that the user has not been authorized; Step 9. When the user equipment starts to parse the first request, the P-CSCF receives the second request at this time, and then repeats the process of the previous steps; Step 10. After the S-CSCF receives the response, if the information is true, it will download the user information from the HSS, and send a "200" message to indicate that the request is successful; Step 11, S-CSCF uses the header file or the public user identifier PUID in the IMS message to select a service framework in the user configuration file to generate the initial service; once the user equipment is authorized successfully, it can initialize and receive the message; Step 12, when the user equipment is deregistered from the IMS, the registration timer is recorded as 0 and a registered information is sent; Step 13. After the registration is successful, the user equipment will receive a message "200 OK" from the S-CSCF, indicating that the entire registration process has been completed; if a user has not registered before, then its public user identification PUID does not currently exist, S-CSCF will process this registration through HSS and assign a public user identification PUID to the user. If the user has registered before, just select a public user identification PUID from S-CSCF to associate with the current user. 2. An IMS system registration device adopting the method according to claim 1, characterized in that: the IMS system registration device comprises: user equipment UE, a sending unit, a receiving unit, an authentication unit and a registration unit; wherein, User equipment UE: mainly used as terminal equipment for accessing the IMS system, using wireless equipment or hardware access equipment; Sending unit: used to send the registration message directly to the S-CSCF according to the S-CSCF address; at this time, the registration message will include the public user identifier PUID, and will continue to send a "200" response after the authentication is successful; When the authentication unit authenticates successfully, it sends a Cx interface push or Cx interface pop message to the HSS; Receiving unit: used to receive the public user identifier PUID assigned to the user equipment UE by each service access point, and receive the P-CSCF discovery list fed back by the access point corresponding to each service; the receiving unit is also used to receive the authentication When the authorization unit is successful, the Cx interface response returned when sending the Cx interface authentication information to the HSS; Registration management unit: this unit is the registration manager, which can act as a proxy for the registration and cancellation of the public user identification PUID from the server; a registration notification sent from the enabler represents the beginning of the entire registration, and the user can enter his/her name on the web page User information is registered; the registration manager, as a registration agent, forwards the registration message to S-CSCF and HSS, and they will assign a private user ID to the user and authorize it; Authentication unit: used for authenticating the user equipment UE, and judging whether to grant the user registration authority; Registration unit: when the authentication is successful, that is, when the user equipment UE receives a response of "200", the IMS system performs an initial registration process in this unit.