Method for implementing inaccessible forwarding of IP multimedia subsystem centralized service consumer

Abstract

The invention discloses a method for realizing call forwarding when a mobile subscriber an IP multimedia subsystem (IMS) centralized service is unreachable, which comprises the following steps: (1) an IMS circuit switched control function (ICCF) entity sends a switched called request message to a visited mobile switch center (VMSC); (2) the VMSC transmits a call to a called subscriber terminal, and sends a mobile application part error response message when finding the subscriber is unreachable; (3) the ICCF entity maps the mobile application part error response message as a session initiation protocol (SIP) response message, and transmits the SIP response message to a telecom application server (TAS); the TAS controls the triggering of the call forwarding service in case the mobile subscriber is unreachable according to a reason value thereof carried by the SIP response message. The method enables the IMS centralized service terminal to realize call forwarding in case the mobile subscriber is unreachable.

Description

Realization method of unreachable forwarding for centralized service users of IP multimedia subsystem technical field The present invention relates to the communication field, and more specifically relates to a method for realizing unreachable forwarding of IP multimedia subsystem centralized service users. Background technique IP (Internet Protocol, referred to as IP) multimedia subsystem (IPMultimediaCoreNetworkSubsystem, referred to as IMS) is an IP-based network architecture proposed by the 3rd Generation Partnership Project (3rd Generation Partnership Project, referred to as 3GPP), which builds an open and flexible business environment, support multimedia applications, and provide users with rich multimedia services. IMS is an IP-based telecommunications network architecture that has nothing to do with access technology, except that it can provide services for packet switched (PacketSwitched, PS) access networks such as GPRS (General Packet Radio Service) and WLAN (W...

AI Technical Summary

Problems solved by technology

As for the judgment of the inaccessibility of the user, the existing technology is: when the called call is established, a paging is issued to the called terminal, and the called user cannot be paged, and the switch judges

It can be seen from the establishment method of the called process described above that the first method does not have a paging process, and the switch has no way to judge

The second method has a paging process, but the existing technology is limited by the capabilities of the MGCF entity, and the MGCF entity cannot convert the ISUP release message carrying the user unreachable cause value into a SIP response message, so these two methods are not feasible

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