scope:

The present document defines call control protocols and procedures for use in the IMS-based PSTN/ISDN Emulation subsystem based on the Media Gateway Control Protocol (MEGACO), the Session Initiation Protocol (SIP), and the associated Session Description Protocol (SDP).

NOTE: The present document relies on the architectural framework defined in TS 182 012 [3] for IMS-based PES Emulation and may need to be updated once the open issues identified in the present document are resolved.

The present document is applicable to:

• the interface between the User Equipment (UE) and the Call Session Control Function (CSCF);

• the interface between the Access Gateway Control Function (AGCF) and the Media Gateway Function (MGF);

• the interface between the Access Gateway Control Function (AGCF) and the Call Session Control Function (CSCF);

• the interface between the CSCF and any other CSCF;

• the interface between the CSCF and an Application Server (AS);

• the interface between the CSCF and the Media Gateway Control Function (MGCF);

• the interface between the S-CSCF and the Multimedia Resource Function Controller (MRFC);

• the interface between the CSCF and the Breakout Gateway Control Function (BGCF);

• the interface between the BGCF and the MGCF;

• the interface between the BGCF and any other BGCF;

• the interface between the CSCF and an external Multimedia IP network;

• the interface between the CSCF and the IBCF.

Not supported services and capabilities

The present document depends on supported capabilities by some other specifications. This situation may lead to some limitations. See clause 6.3.5 and annex I.