3GPP Work Item description

This page contains informal descriptive text only.  See master WID page for further details.

Building block:     Interworking between IMS and IP networks

IP based multimedia services are a required feature of UMTS, which will include IP telephony and real time service support with end to end QoS negotiation.

The UMTS architecture has to  interwork with other, wider, IP networks through the GGSN and Mb reference point. This work item will define the solutions required to implement user plane and control plane interworking over this reference point. The interworking requirement may be especially true for IP based networks that do not support potential user plane aspects which are specific to mobile networks (e.g. those selected for radio resource optimization reasons).

Significant goals are to define the functionality required within the GGSN and CSCF to enable this service interworking, and to establish the protocols over the Mb and Mm reference points.

The work item will address the issue of control plane interworking between standard SIP (as defined in IETF) and SIP with 3GPP extensions, which is being developed in CN1 (in TSs 24.228/24.229). This will , enable the IM CN subsystem to communicate with external IP networks that use IP multimedia session control protocols.

The work item will address the issue of user plane interworking, for example, between the AMR codec used in the IM CN subsystem and other codec types used within external IP networks. This may be required when interworking with SIP based external IP networks.

As regards user plane interworking, the areas addressed should encompass the transport protocol and the signaling issues for negotiation and mapping of bearer capabilities and QoS information.

Work to be led by N3.