Method for calling user terminal of IP multimedia subsystem

Abstract

The invention relates to a method for calling the user terminal of IP multimedia subsystem, which comprises: the inquire-call conservation control function module (I-CSCF) inquires the register position of called user to the attaching user server (HSS); I-CSCF, based on the response of HSS, sends the conservation initialize protocol (SIP) request to the service-call conservation control function module (S-CSCF); when the S-CSCF is overtime to the response of SIP sent from I-CSCF, I-CSCF reselects S-CSCF, and sends SIP request to S-CSCF. With said invention, if the S-CSCF that processing the IMS non-registered service feedback from HSS, do not feedback response caused by device accidence or communication interruption, I-CSCF can reselect other S-CSCFA to process said non-register service of said IMS user, to improve the service quality.

Description

technical field [0001] The invention relates to a communication technology, in particular to a method for calling a user terminal of an IP multimedia subsystem. Background technique [0002] In an IMS (IP Multimedia Subsystem) network, when a UE (User Terminal) of an IMS user is called, the I-CSCF (query CSCF (call session control function module)) of the called network will pass Cx-Location- The Query command queries the HSS (Home Subscriber Server) about the registration location of the IMS user. [0003] If the IMS user subscribes to an unregistered service (such as voice mail transfer, etc.), when the IMS user is in the UNREGISTERED (unregistered) state or the relevant ID (identity identification) (such as the user terminal sharing the same number with the IMS user) has When the registration or related ID (such as the user terminal sharing the same number as the IMS user) is in the UNREGISTERED state, the HSS will return the S-CSCF that handles the unregistered service ...

AI Technical Summary

Problems solved by technology

[0006] When the S-CSCF forwards the SIP request or processes the registered service or unregistered service of the IMS user, if the S-CSCF fails to Response will cause the session timeout, so that the SIP request on the calling side will fail due to timeout (may cause call loss)

[0007] When the called IMS user is in the UNREGISTERED state or the related ID has been registered or the related ID is in the UNREGISTERED state, the unregistered service of the called IMS user will also not be executed , so that the IMS network may not be able to provide the correct service for the IMS user for a long time (until the S-CSCF restores the service or the called IMS user successfully registers with other normal S-CSCF after powering on, the IMS network cannot provide the IMS service for the IMS user. The user provides the correct business, and the process may last for a long time, such as hours, days or even longer)

Images