ABSTRACT
Implementations of softswitches, IP-MSC, and IP-VPN are not described here. This chapter concentrates on the IMS specific features that interface with CSN.
The key IMS element for interworking with CSNs is the MGCF, which is responsible for managing the gateways toward CSNs and performs much of the feature translation. Aspects of PSTN Emulation and Simulation are explained here, along with the treatment of supplementary services, though not full service emulation details. The focus here is on the interaction with IMS, and in particular-the solution of connecting POTS to IMS via an AGCF utilizing the IMS session control is detailed. Finally, this chapter also describes the IMS Transit facility to transport transparently both CSN communications as well as IP across other networks.
