scope:

The present document describes the protocol to be used on the Media Gateway Control Function (MGCF) - IM Media Gateway (IM-MGW) interface. This interface provides the Media Gateway Control for interworking between the IP Multimedia Subsystem (IMS) and CS domain (ISUP, BICC and SIP-I). The basis for this protocol is the H.248 protocol as specified in ITU-T. The IMS architecture is described in 3GPP TS 23.228 [1]. The interaction of the MGCF-IM MGW interface signalling procedures in relation to the SIP, and BICC/ISUP signalling at the MGCF are described in 3GPP TS 29.163[4].

The interaction of the MGCF-IM MGW interface signalling procedures in relation to the IMS SIP and SIP-I on Nc at the MGCF are described in 3GPP TS 29.235[47].

This specification describes the application of H.248 on the Mn interface. Required extensions use the H.248 standard extension mechanism. In addition certain aspects of the base protocol H.248 are not needed for this interface and thus excluded by this profile.

In addition this profile provides support for PSTN/ISDN Emulation as required by ETSI TISPAN.

The specification contains a normative Annex defining the H.248.1 Profile in accordance with ITU-T recommendations for H.248.1 applications. Where there exists any contradiction between the normative Annex A and the rest of the specification, the Nornative Annex shall take precidence. The main body of the specification provides an introduction to the use of the profile for the Mn interface and introduces any specific functionality (e.g. new packages) associated to the Mn.