Abstract: A method for implementing service interaction in the IP multimedia subsystem is disclosed in the present invention, wherein each service logic has a unique service identifier. The method comprises the following steps: (a) a Serving-Call Session Control Function (S-CSCF) sends a session initiation protocol (SIP) request message to the service capability interaction manager (SCIM) or to the application server (AS) to which a user requests for a service; (b) after the AS or SCIM has received the request and has executed this service, it inserts the service identifier of this service into the SIP request, and returns the SIP request with the service identifier to said S-CSCF. With the present invention, most of the service interaction requirements can be satisfied.

Abstract: A method for matching initial request messages in the IP multimedia subsystem service triggering process comprises: before the S-CSCF forwards an initial request message to the AS, generating a trigger request identifier uniquely and inserting the identifier into the initial request message; then forwarding the initial request message to the AS; and then the AS copies the trigger request identifier in the received message into the initial request message to be sent back; finally, the S-CSCF determines whether a received initial request message is the response to the initial request message sent to the AS by the S-CSCF previously based on the trigger request identifier, determines the corresponding relationship, and then performs the subsequent service control process. With the present invention, the requirement that the S-CSCF must correctly match the initial request message with the one sent back can be satisfied, thus guarantee the normal performance of service triggering.

Abstract: A realizing method of emergency registration is disclosed. When the user equipment in the visited network initiates an emergency registration request, the method comprises the following steps: after P-CSCF of the visited network receives the emergency registration request sent from the user equipment, it forwards the message to S-CSCF of the home network. The S-CSCF sets the emergency registration expiration time according to the setting policy for emergency registration expiration time, includes it into the emergency registration response sent to the P-CSCF which retrieves the emergency registration expiration time from the emergency registration response and sends the message to the user equipment, which in turn retrieves the emergency registration expiration time from the emergency registration response.