CN1874279A - Method for treating abnormity of registration in procedure of registering users - Google Patents

Abstract

The invention discloses a method for processing abnormal registration during the user registration process. In the method, the Inquiry Call Session Control Function (I-CSCF) entity in the IMS network domain forwards the registration message to the Serving Call Session Control Function (S-CSCF) When the CSCF entity determines that the registration is abnormal, it notifies the Home Subscriber Server (HSS), and the HSS marks the S-CSCF entity; and in the subsequent registration process of the terminal device, the HSS accepts the query request of the I-CSCF entity and detects When receiving the marking from the S-CSCF entity, at least the required capability data for selecting the S-CSCF is carried in the response message returned to the I-CSCF entity.

Description

How to handle exceptions during user registration

technical field

The invention relates to an IP-based multimedia subsystem (IMS) network in the communication field, in particular to a method for processing abnormal registration during user registration in the IMS network.

Background technique

With the development of broadband network, mobile communication is not limited to traditional voice communication, but through the communication with data services such as presence, short message, web page (WEB), location information, push service (PUSH) and file sharing, etc. Combined, mobile communication can realize services of multiple media types such as audio, video, picture and text, so as to meet various needs of users.

For example, short message services can provide instant messaging, chat rooms, and multimedia short message services; video services can provide services such as entertainment, multimedia information, and daily communication; e-commerce services can provide product catalogs, search engines, shopping carts, order management and Payment and other services; the game business can provide services such as single-player games and group games; the positioning business can provide services such as tracing, guides, and alarms; the personal assistant business can provide address book, schedule, bookmark management, file storage, and event reminders and services such as email.

Driven by various applications, organizations such as the 3rd Generation Partnership Project (3GPP) and the 3rd Generation Partnership Project 2 (3GPP2) have launched the IP-based Multimedia Subsystem (IMS) architecture. The purpose is to use a standardized open structure to realize a variety of multimedia applications in the mobile network, so as to provide users with more choices and richer experience.

As shown in FIG. 1 , the IMS architecture is superimposed on the packet domain network (PS-Domain), and entities related to security functions include Call Session Control Function (CSCF) entities and HSS functional entities. CSCF can be further divided into three logical entities: Serving CSCF (S-CSCF), Proxy CSCF (P-CSCF) and Inquiring CSCF (I-CSCF). The three logical entities may be located on different physical devices, or may be the same Different functional modules in a physical device. S-CSCF is the service switching center of IMS, which is used to perform session control, maintain session status, manage user information, generate billing information, etc.; P-CSCF is the access point for terminal users to access IMS, and is used to complete user registration. Quality of Service (QoS) control and security management, etc.; I-CSCF is responsible for the intercommunication between IMS domains, manages the allocation of S-CSCF, hides network topology and configuration information from the outside, and generates charging data, etc. The HSS is a very important user database used to support the processing of calls and sessions by various network entities.

IMS is only considered to be used in the third generation mobile communication network when it is initially launched (R5 protocol). Since the services on the IMS are very rich, there is a need for operators to use the IMS on the 2G network. However, 2G networks cannot support the security-related functions of IMS based on 3G networks. In order to provide IMS services to end users on 2G networks, TR 33.878/TR33.978 defines the EarlyIMS access domain security mechanism. The scheme is The IMS service on 2G provides certain security functions, and when the network is upgraded to 3G, it will support complete 3G-based IMS security functions.

The security function of the existing 2G-based IMS is implemented in this way: the user first accesses the 3GPP packet domain, and the packet domain network will perform access authentication for the user, and after the access authentication passes, the packet network gateway node of the packet network (GGSN) allocates an IP address to the user, and this IP address is also the IP address used by the user when using the IMS subsystem service. The GGSN notifies the HSS of the IP address and the user's telephone number (MSIDSN) or International Mobile Subscriber Identity (IMSI) through an intermediate entity, and the HSS finds the user's identity IMPI in the IMS system through the user's MSISDN or IMSI, and sends the The user's IMPI, MSISDN, IP address and other information are bound and saved. When a user wants to use IMS, it will first send a registration request message (register), and this message will reach the S-CSCF after being forwarded by the intermediate entity, and the S-CSCF will obtain the binding relationship between the user's IMPI and IP address from the HSS and Save, then the S-CSCF checks whether the identity mark from the user and the IP address it uses match the binding of the identity mark (IMPI) and the IP address it saves, if so, it is considered to be a legal user and controls the User access, the user is allowed to use IMS services, otherwise it is considered an illegal user, and the 2G user access is rejected. When the user releases the IP address, the GGSN needs to notify the HSS. The HSS can then initiate a logout process on the network side according to the message.

When processing the Full 3GPP Compliant authentication method, the I-CSCF entity needs to determine whether the user's registration is initial registration or repeated registration. This is because if the I-CSCF entity sends the SIP registration message to the S-CSCF entity, the selected S-CSCF entity may be inaccessible due to the failure of the S-CSCF entity itself or other reasons. At this time, the I-CSCF entity needs to judge whether the user's registration message is an initial registration or a subsequent registration according to some specific information in the Authorization header field in the SIP registration message. If it is an initial registration, the I-CSCF entity can re-select a new S - The CSCF entity forwards the registration message again. If it is a subsequent registration message, the I-CSCF entity cannot reselect the S-CSCF entity, and can only return a 408 (request timeout) response message or a 504 (server timeout) response message to the user.

In the Early IMS authentication method, the registration message sent by the UE will no longer carry the Authorization header field, and there is no IPSec tunnel between the UE and the P-CSCF. Originally, according to whether the message is protected, the message is judged as initial It is no longer possible to register or re-register. When the S-CSCF entity selected by the I-CSCF entity cannot be accessed, the I-CSCF entity will not be able to determine whether the received SIP registration message is initial registration or subsequent re-registration. If the I-CSCF considers that no Authorization is carried as the initial registration (one without protection is interpreted as protection equal to "NO"), reselection is performed. This will cause the UE to see that it is performing re-registration, but the network re-assigns an S-CSCF to it. Therefore, the session state/registration information related to the original S-CSCF on the UE does not describe how to deal with it according to the existing standards, that is, the UE may retain or delete it, which may cause some states that should be deleted on the UE side to not be deleted. . For a network element (such as an S-CSCF) that needs to distinguish whether the registration is an initial registration or a repeated registration, it will not be possible to determine subsequent related processing measures.

In addition, the existing technology does not distinguish the registration type when the registration is abnormal. For a logout non-subsequent re-registration message initiated by the user, according to the current standard, an S-CSCF will be re-selected on the I-CSCF side. If the user is an illegal user As a result, the deregistration cannot succeed on the network side, and the newly elected S-CSCF will not replace the old S-CSCF on the HSS side. As a result, this re-election is meaningless to the network side, and may instead cause a burden on the network. Therefore, the I-CSCF needs to judge for non-subsequent re-registration messages, and does not need to re-select every time.

Contents of the invention

The present invention provides a method for processing abnormal registration during the user registration process, so as to solve the problem in the prior art that the network equipment cannot determine the follow-up processing measures when the registration is abnormal when the initial registration and re-registration cannot be distinguished.

The invention also solves the problem that the prior art does not distinguish between registration types when the registration is abnormal, which may increase the network load.

In order to solve the above problems, the present invention provides the following technical solutions:

A method for processing exceptions during user registration, the method includes the following steps:

When the Inquiring Call Session Control Function (I-CSCF) entity in the IMS network domain forwards the registration message of the terminal equipment to the Serving Call Session Control Function (S-CSCF) entity and determines that the registration is abnormal, it notifies the Home Subscriber Server (HSS), marking said S-CSCF entity by the HSS; and

In the subsequent registration process of the terminal device, when the HSS accepts the query request from the I-CSCF entity and detects the mark of the S-CSCF entity, the response message returned to the I-CSCF entity carries at least the selected S-CSCF The required capability data.

in:

The response message further includes the S-CSCF entity that has been assigned to the public user identity (IMPU). If the I-CSCF entity cannot judge whether it is an initial registration message according to the received SIP message, then the S-CSCF entity is preferentially selected and Forward registration messages.

The Early IMS authentication method is adopted in the registration process of the terminal device.

In the subsequent registration process, if the I-CSCF entity forwards the registration message to the S-CSCF entity and determines that the registration is abnormal, select another S-CSCF entity according to the delivered capability data and forward the registration message to it .

Before notifying the HSS, the I-CSCF entity further judges whether the registration message is a deregistration non-subsequent message, and if so, directly returns a failure message to the terminal device; otherwise, if it is a subsequent message, it is processed according to the current standard. Otherwise, if it is a registration non-follow-up message, notify the HSS.

After the HSS marks the S-CSCF entity, it returns a response message to the I-CSCF entity. After the I-CSCF entity receives the response message, if the I-CSCF entity cannot determine whether it is an initial registration message based on the received SIP message, it returns to the terminal device. Registration failure message. If the I-CSCF entity can judge the received SIP message as an initial registration message, then the I-CSCF entity can perform the next step of processing according to the response message.

The failure message includes the reason for the registration failure.

After receiving the failure message, the terminal device further deletes the registration state of other related public user identities (IMPU) and the related session state.

A method for handling registration exceptions in a user registration process, the method includes the following steps:

When the Inquiry Call Session Control Function (I-CSCF) entity in the IMS network domain forwards the registration message initiated by the terminal equipment to the Serving Call Session Control Function (S-CSCF) entity and determines that the registration is abnormal, determine the type of the registration message;

If the registration message is a logout non-subsequent type, a failure response is returned to the terminal device; if it is a subsequent message, it is processed according to the current standard; otherwise, if the SIP message is a registration type, subsequent exception processing is performed.

in:

When handling exceptions, if the I-CSCF determines that the terminal device adopts the EarlyIMS authentication mode during the registration process, it notifies the HSS, and the HSS marks the S-CSCF.

In the subsequent registration process of the terminal device, when the HSS accepts the query request from the I-CSCF entity and detects the mark of the S-CSCF entity, the response message returned to the I-CSCF entity carries at least the selected S-CSCF The required capability data.

In the registration process using Early IMS authentication and similar authentication methods, the I-CSCF notifies the HSS when the I-CSCF finds that the S-CSCF is invalid, and the HSS marks it; in the subsequent registration process of the terminal device, the HSS responds to the I-CSCF query When the assigned S-CSCF detects this mark, the message returned to the I-CSCF must carry the capability data of the assigned S-CSCF. Therefore, in the subsequent registration process, the I-CSCF finds the assigned S-CSCF When it fails, and the currently used authentication method cannot judge whether it is an initial registration message based on the received SIP message, another suitable S-CSCF can be selected for subsequent processing according to the capability data, so that the registration process can be successfully completed.

Description of drawings

FIG. 1 is a schematic diagram of an existing IMS network structure;

Fig. 2 is the main processing flowchart when registration is abnormal among the present invention;

Fig. 3 is a schematic diagram of detailed processing when the I-CSCF finds that the S-CSCF fails in the embodiment of the present invention.

Detailed ways

During the registration process, the I-CSCF sends a Cx-UAR command to the HSS to request the HSS to allocate an S-CSCF according to the normal processing flow. According to the response message, the processing of the HSS can be divided into three situations:

A. Return a specified S-CSCF;

B. Return the required S-CSCF capability set for the I-CSCF to select a suitable S-CSCF;

C. Return a specified S-CSCF, and also include the required S-CSCF capability set for the I-CSCF to select a suitable S-CSCF.

In the above three cases, the I-CSCF needs to select an S-CSCF, and forward the SIP registration message to the designated S-CSCF. In abnormal circumstances, such as S-CSCF or other reasons such as network failure, the SIP message is forwarded to the designated S-CSCF without response message. In the current 3GPP standard, the I-CSCF needs to judge whether the SIP registration message is protected according to the relevant content in the Authorization header field in the SIP registration message, and process the response message, such as reselecting an S-CSCF or Give the user a failure response message. After 3GPP introduces the Early IMS authentication method, in the Early IMS authentication process, the SIP registration message initiated by the UE will no longer contain the Authorization header field, thus making it impossible to use this header field to determine whether the SIP message is protected. Therefore, for the registration process in which the registration request message has no information about whether the registration request message is protected, after the I-CSCF fails to select a designated S-CSCF and forward the registration message, it cannot determine whether the SIP message is protected. Follow up. One understanding is that the lack of the header field is equivalent to the message being the initial registration message, but due to the lack of relevant processing behaviors at the UE, processing exceptions will result.

In the Early IMS authentication process, if the HSS returns a specified S-CSCF, this is because the user’s IMPU or other related IMPUs have been registered with a specified S-CSCF, the HSS must ensure that the user’s related IMPUs are in the same On one S-CSCF. In addition, it is also possible that the relevant IMPU of the user is in the Unregistered state and remains on a specified S-CSCF, and the HSS considers that there is no need to re-allocate an S-CSCF at this time.

The present invention adopts the registration process of Early IMS authentication and the situation that HSS returns a designated S-CSCF, when I-CSCF forwards the registration message to the Serving Call Session Control Function (S-CSCF) entity and then determines that the registration is abnormal (such as S - CSCF is faulty), notify the Home Subscriber Server (HSS), and the HSS will mark the S-CSCF entity; in the subsequent registration process of other IMPUs under the same user or the same IMS SUBSCRIPTION, the HSS accepts the query of the I-CSCF entity When requesting and detecting that the S-CSCF entity assigned to the user has the mark, the response message returned to the I-CSCF entity shall at least carry the required capability data for selecting the S-CSCF, so that the I-CSCF may use the Capability data re-select S-CSCF.

Referring to Figure 2, the main process of registering an exception is as follows:

1. After the I-CSCF forwards the registration message to the designated S-CSCF and determines that the S-CSCF is invalid, and determines that the registration message is the Early IMS authentication mode, the I-CSCF notifies the HSS through the Cx interface that the S-CSCF is faulty.

Further, the I-CSCF can perform optimized processing, namely: first judge whether the SIP message is a registration message or a deregistration message, and if the SIP message is a deregistration message (that is, the value of Expire in the SIP message is 0), then the I-CSCF can directly send a message to the terminal The device returns a corresponding error message; if the I-CSCF judges that the SIP message is a registration message (that is, the Expire value in the SIP message is not 0), proceed to the subsequent step 2.

2. After receiving the failure notification message from the I-CSCF, the HSS determines that the IMPU is an Early IMS authentication type, and it makes a special mark on the S-CSCF that the IMPU originally registered with.

For the IMPU non-Early IMS authentication type, the HSS shall return an error response message to the S-CSCF.

The method that can be considered is that the I-CSCF explicitly states in the Cx-UAR message that it needs to obtain the capability. After the HSS obtains the message and judges that the IMPU is an Early IMS authentication type, it sets the S-CSCF assigned to the IMPU. A special flag to indicate that the S-CSCF may be unavailable. When the subsequent HSS receives the UAR query response from the user, it shall return the S-CSCF registered with the IMPU to the I-CSCF and also include the S-CSCF capability information. That is to tell the I-CSCF that the designated S-CSCF is just a recommendation, not a mandatory requirement.

3. After the I-CSCF receives the response message from the HSS, no matter whether the response message contains information for further S-CSCF reselection, the I-CSCF cannot immediately perform S-CSCF reselection at this time, but should only Return a failure message to the user, such as 408/500/504 (according to the existing technology, usually the above-mentioned I-CSCF explicitly requires the capability of the S-CSCF, and the HSS will return the capability data, and the I-CSCF will return the capability data according to the capability data , the I-CSCF can perform subsequent S-CSCF selection).

The reason for the failure may be further included in the failure message, for example, the reason is that the S-CSCF is faulty.

4. After receiving the failure message, the UE judges that the S-CSCF originally registered on the network side is faulty according to the information contained in the message or other methods (such as multiple registration failures), and after local processing, the UE initiates a new IMPU register.

If the UE has other relevant IMPUs registered locally or subscribed to some relevant information at this time, the UE should delete the registration status of other IMPUs at this time, and initiate a new registration of the IMPU after confirming that all local registration statuses have been cleared.

5. After receiving the UE's registration request, the I-CSCF initiates a query request to the HSS.

6. After the HSS receives the Cx-UAR command, the IMPI of the inquired IMPU includes the Early IMS authentication type and learns that the S-CSCF originally registered by the IMPU may be faulty according to the special mark of the S-CSCF. The returned message will contain the S-CSCF (the IMPU was originally registered) and the S-CSCF capability data.

After receiving the message returned by the HSS, the I-CSCF generally selects the recommended S-CSCF first and forwards the SIP message to it. If the I-CSCF entity forwards the registration message to the S-CSCF entity and determines that the S-CSCF is abnormal, it must judge the authentication method currently used by the user according to the received SIP registration message. - The CSCF cannot determine whether the received SIP message is an initial registration message, and the I-CSCF selects another appropriate S-CSCF entity according to the capability data and forwards the registration message to it.

As shown in Figure 3, during the registration process using the Early IMS authentication method, the processing steps for registration exceptions are as follows:

Steps 1-4: The UE adopting the Early IMS authentication mode sends a registration message to the network, and the message is forwarded to the I-CSCF of the user's home network via the P-CSCF.

In step 5-6, the I-CSCF sends a Cx-UAR message to the HSS to obtain the location information of the S-CSCF registered by the IMPU. It is assumed here that the IMPU already has an assigned S-CSCF on the network side. Therefore, the HSS only returns the specified S-CSCF to the I-CSCF.

Processing flow A: The I-CSCF forwards the SIP registration message to the designated S-CSCF. It is assumed here that the S-CSCF is faulty, and thus the S-CSCF cannot respond correctly to the I-CSCF.

In steps 7-8, after the I-CSCF judges that the S-CSCF is faulty, and according to the SIP registration message, it is judged that the IMPU is of Early IMS authentication type. At the same time, the I-CSCF can further judge whether the received registration message is a registration message or a deregistration message, and there is a possibility of further process optimization. If the I-CSCF judges that the registration message is a deregistration message, the I-CSCF will no longer send the S-CSCF fault indication to the HSS, but only return a registration failure response message to the user. Of course, the I-CSCF may not perform the optimization process, that is, the I-CSCF does not judge whether the registration message is a registration message or a deregistration message.

The I-CSCF sends an S-CSCF failure indication to the HSS, notifying the HSS that the S-CSCF may fail. The HSS returns a message to the I-CSCF confirming receipt of the message. During this process, the HSS must determine whether the IMPI to which the IMPU belongs includes the Early IMS authentication type. If the IMPI to which the IMPU belongs includes the Early IMS authentication type, it needs to set a special header on the S-CSCF assigned to the IMPU. , to indicate that the S-CSCF may be faulty.

In steps 9-10, the I-CSCF returns the registration failure message to the user after confirming that the HSS has received the failure indication. The registration failure message may further include indication information that the cause of the registration failure is a failure of the S-CSCF on the network side.

Processing flow B: After receiving the registration failure response message, the UE judges that the S-CSCF on the network side may be faulty according to the indication information in the failure response message or other methods. The UE deregisters all IMPUs related to the S-CSCF on it. During this process, the UE may send a deregistration message to the network side, or may not send a deregistration message to the network side.

In steps 11-14, when the UE determines that all the relevant IMPUs on it are in the non-registered state, the UE may send a registration message to the network side again. The registration message is forwarded to the I-CSCF through the P-CSCF according to the method similar to the above.

In steps 15-16, the I-CSCF sends a Cx-UAR message to the HSS to query the S-CSCF allocated to the IMPU by the network side. The HSS has allocated an S-CSCF to the IMPU previously, and the HSS has made a special mark on it during the last user registration process to record the possibility of failure of the allocated S-CSCF (steps 7-8).

Therefore, the HSS must determine whether the IMPI of the IMPU that performs the Cx-UAR query includes the Early IMS authentication type. If it is determined that the IMPI of the IMPU performing the Cx-UAR query includes the Early IMS authentication type, when the HSS returns to the I-CSCF the S-CSCF assigned to the IMPU, it will return the recorded S-CSCF and the IMPU if reselected The S-CSCF capability data required by the S-CSCF (if it is determined that the IMPI of the IMPU that performs the Cx-UAR query does not include the Early IMS authentication type, the HSS will process it in the normal way, that is, the HSS can only return the specified S-CSCF ).

Processing flow C: After the I-CSCF receives the specified S-CSCF and S-CSCF capability data returned from the HSS, the I-CSCF must judge the authentication method currently used by the user according to the received SIP registration message. The currently used authentication method prevents the I-CSCF from judging whether the received SIP message is an initial registration message, so the I-CSCF preferentially selects the designated S-CSCF and forwards the registration message to it. If it is found that the S-CSCF does not respond or has other failures, the I-CSCF shall select the next S-CSCF according to the capability data.

Step 17: After the I-CSCF determines the selected S-CSCF, the I-CSCF forwards the registration message to the designated S-CSCF, and the designated S-CSCF performs subsequent processing according to the usual registration process.

For other registration processes that do not contain security instructions in the registration message, the processing method when the registration is abnormal is the same as the processing method for the registration using the Early IMS authentication method above, and will not be described again.

In addition, for the registration process using the Early IMS authentication method or the FULL authentication method, if the I-CSCF forwards the registration message initiated by the terminal device to the Serving Call Session Control Function (S-CSCF) entity and determines that the registration is abnormal, it can first judge The type of the registration message; if the registration message is a logout non-subsequent message type, a failure response is returned to the terminal device. If it is a follow-up message, it will be processed according to the current standard; otherwise, if the SIP message is a registration type non-follow-up message, follow-up exception handling will be performed. For the registration process of the FULL authentication mode, the processing of the registration exception can be carried out according to the existing method; for the registration process of the EarlyIMS authentication mode, the processing of the registration exception can be carried out according to the above method, that is, the I-CSCF notifies the HSS, and the HSS Mark the S-CSCF; refer to the previous description for other processing.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (12)

1. A method for handling registration exceptions during user registration, characterized in that the method comprises the following steps: When the Inquiring Call Session Control Function (I-CSCF) entity in the IMS network domain forwards the registration message of the terminal equipment to the Serving Call Session Control Function (S-CSCF) entity and determines that the registration is abnormal, it notifies the Home Subscriber Server (HSS), marking said S-CSCF entity by the HSS; and In the subsequent registration process of the terminal device, when the HSS accepts the query request from the I-CSCF entity and detects the mark of the S-CSCF entity, the response message returned to the I-CSCF entity carries at least the selected S-CSCF The required capability data. 2. The method according to claim 1, wherein the response message further includes the S-CSCF entity assigned to the public user identity (IMPU), and if the I-CSCF entity cannot judge according to the received SIP message Whether it is an initial registration message, the S-CSCF entity is preferentially selected and the registration message is forwarded. 3. The method according to claim 1 or 2, characterized in that the Early IMS authentication method is used for the terminal device during the registration process. 4. The method according to claim 3, wherein in the subsequent registration process, if the I-CSCF entity forwards the registration message to the S-CSCF entity and determines that the registration is abnormal, then select another option according to the capability data An S-CSCF entity and forwards registration messages to it. 5. The method according to claim 1, wherein the I-CSCF entity further judges whether the registration message is a deregistration message and is a non-subsequent message before notifying the HSS, and if so, directly returns a failure message to the terminal device, Otherwise, if it is a follow-up message, it will be processed according to the current standard; otherwise, if it is a registration non-follow-up message, the HSS will be notified. 6. The method according to claim 1, wherein the HSS marks the S-CSCF entity and returns a response message to the I-CSCF entity, and after the I-CSCF entity receives the response message, if the I-CSCF entity cannot The SIP message judges whether it is an initial registration message, and then returns a registration failure message to the terminal device. If the I-CSCF entity can judge the received SIP message as an initial registration message, then the I-CSCF entity can perform the next step of processing according to the response message. 7. The method according to claim 6, wherein the failure message includes a reason for the registration failure. 8. The method according to claim 6, characterized in that, after receiving the failure message, the terminal device further deletes the registration state of the related other public user identity (IMPU) and the related session state. 9. A method for handling registration exceptions during user registration, characterized in that the method comprises the following steps: When the Inquiry Call Session Control Function (I-CSCF) entity in the IMS network domain forwards the registration message initiated by the terminal equipment to the Serving Call Session Control Function (S-CSCF) entity and determines that the registration is abnormal, determine the type of the registration message; If the registration message is a logout type and a non-subsequent message, then return a failure response to the terminal device; if it is a subsequent message, it will be processed according to the current standard; if the SIP message is a registration type and a non-subsequent message, follow-up exception handling. 10. The method according to claim 9, wherein when handling the exception, if the I-CSCF determines that the terminal device adopts the Early IMS authentication mode during the registration process, it will notify the HSS, and the HSS will verify the The S-CSCF performs marking. 11. The method according to claim 10, characterized in that, in the subsequent registration process of the terminal equipment, when the HSS accepts the query request of the I-CSCF entity and detects the mark of the S-CSCF entity, it sends The response message returned by the I-CSCF entity at least carries the required capability data for selecting the S-CSCF. 12. The method according to claim 10, wherein the response message further includes the S-CSCF entity that has been allocated to the public user identity (IMPU), if the I-CSCF entity cannot judge according to the received SIP message Whether it is an initial registration message, the S-CSCF entity is preferentially selected and the registration message is forwarded.

Images