This TS specifies the principles of interworking between the 3GPP IM CN subsystem and BICC/ISUP
based legacy CS networks, in order to support IM basic voice, data and multimedia calls.
This TS addresses the areas of control and user plane interworking between the IM CN subsystem and CS
networks through the network functions, which include the MGCF and IM-MGW. For the specification of control plane
interworking, areas such as the interworking between SIP and BICC or ISUP are detailed in terms of the processes and protocol mappings required for the support of both IM originated and terminated voice and multimedia calls.
Other areas addressed encompass the transport protocol and signalling issues for negotiation and mapping of bearer
capabilities and QoS information.
This TS specifies the interworking between 3GPP profile of SIP (as detailed according to TS 24.229
) and BICC or ISUP, as specified in ITU-T Recommendations Q.1902.1 to Q.1902.6 and ITU-T Q.761 to Q.764 respectively.
This TS also specifies the interworking between circuit switched multimedia telephony service, as
described in TS 26.110
, TS 26.111
, and ITU-T Recommendation H.324 and packet switched
multimedia services, as described in TS 26.235
and TS 26.236
, in particular and the interworking between the 3GPP profile of SIP and the inband control protocols for multimedia communication as specified in ITU-T Recommendations H.245 and H.324 Annex K.
This TS addresses two interworking scenarios with respect to the properties of the CS network:
The CS network does not use any 3GPP specific additions.
The CS network uses 3GPP specific additions.