Interworking between the 3GPP CS domain with BICC or ISUP as signalling protocol and external SIP-I networks
The present document defines interworking procedures between a 3GPP CS domain (see 3GPP TS 23.205 [2]) which applies either BICC or ISUP as signalling protocol, and external networks that use SIP-I (see ITU-T Q.1912.5 [20], Profile C) as signalling protocol. The document also describes the related interworking architecture. The control plane interworking is performed by an interworking unit at the interconnection between the 3GPP CS domain and an external SIP-I network. The user plane interworking is performed by an MGW. The present document defines stage 2 procedures for the control of the MGW.
The present specification reuses existing interworking procedures of 3GPP TS 29.163 [4] and ITU-T Q.1912.5 [20], Profile C, as far as possible.