E.4.1 Introduction

29.1633GPPInterworking between the IP Multimedia (IM) Core Network (CN) subsystem and Circuit Switched (CS) networksTS

This clause describes requirements for extensions to the Mn interface protocol in 3GPP TS 29.332 [15] needed to support the Interworking of multimedia calls. ITU-T Recommendation H.248.1 [2] is used at the Mn interface.

The H.245 signalling shall be handled by the MGCF. Upon reception of the H.245 messages from the CS side at the IM-MGW, the IM-MGW shall forward those H.245 messages as binary data within H.248 messages over the Mn interface towards the MGCF. Upon reception of encapsulated binary H.245 messages within H.248 messages, the IM-MGW shall forward those H.245 messages towards the CS side.

NOTE: Procedures to support MONA (see Annex K of ITU-T Recommendation H.324 [81]) over the Mn interface are not defined in the present Release. Furthermore, the signalling flows in clause E.2 may not show MONA related signalling in sufficient detail for MONA related Mn interface interactions.