Media gateway control function
The media gateway control function (MGCF) and the IMS media gateway function (IMS-MGW) are the controller/processor bridge between the IMS and circuit-switched domain. This visual examines the role of the MGCF .
Simply put, the MGCF enables the interworking between the IMS user and a user in the circuit-switched domain. On an incoming call from a user in the circuit-switched domain, the ISDN User Part (ISUP) or Bearer Independent Call Control (BICC) signals are converted to the appropriate SIP protocols and then the session is forwarded to the IMS. For a call from the IMS to a user in the circuit-switched domain, the reverse is followed. The MGCF also controls the sessions on the user-plane level via the IMS-MGW. As we saw with other entities, the MGCF can forward accounting information to the CCF and OCS.