SERVICE DIFFERENTIATION IN THE IP MULTIMEDIA SUBSYSTEM UTILIZING CONTEXT-AWARE SIGNALING

摘要

A system and method for service differentiation enabling a user to express the level of importance of a session being established and change the level during the session while satisfying QoS profiles. An extension of the 3GPP IMS architecture includes a Session Prioritization Function (SPF) in communication with a S-CSCF and a Context Information Base (CIB) which provides network contextual information. Upon receiving a session initiation or change request, the S-CSCF queries the SPF for aresource allocation/deallocationdecision. The SPF consultssession prioritization policies and the contextual information tomake an informed decision. If the load on the IMS network is normal or light, the SPF utilizes an upper limit policy to limit resources for each service class. Otherwise, the SPF limits the size of multi-party sessions and utilizes soft and hard preemption to transfer network resources between classes. The SPF may trigger the S-CSCF to re-negotiate media-format parameters if network contextual information changes.