Call forwarding in an IP multimedia subsystem (IMS)
US8059633B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 27, 2005 |
| Grant date | Nov 15, 2011 |
| Priority date | — |
| Expiry date | Aug 9, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L65/1104
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A method and Serving Call/State Control Function (S-CSCF) for handling a Session Initiation Protocol (SIP) communication within an IP Multimedia Subsystem (IMS), wherein the communication is subject to a call-forwarding operation handled by a SIP Application Server (AS). An INVITE is received at the S-CSCF, which serves a user equipment (UE) identified by an R-URI. The S-CSCF adds a URI for the S-CSCF to the INVITE route header together with an Original Dialog Identifier (ODI) mapped to the R-URI. The S-CSCF forwards the INVITE to the AS, which changes the R-URI to a URI of a UE to which the call is to be forwarded. The AS adds a forwarding indicator to the INVITE and returns it to the S-CSCF. The S-CSCF identifies the forwarding indicator and determines the original R-URI based on the ODI received in the returned INVITE. The S-CSCF determines call restrictions and Initial Filter Criteria (IFCs) based on the original R-URI.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.