10.2.0 Introduction

29.1623GPPInterworking between the IM CN subsystem and IP networksRelease 17TS

The following functions shall be supported by the TrGW:

– Gate Management including:

– Opening/closing of gates;

– Remote source address filtering; and

– Remote source port filtering;

– QoS packet marking (differentiated services);

– NAPT and IP Version Interworking;

– Bandwidth policing;

– Hanging termination detection;

– IP Realm Indication;

– Media Control; and

– Through-Connection.

Additionally, the following functions may be supported by the TrGW:

– Resource allocation per flow;

– Media Inactivity Detection;

– IP Realm Availability;

– Optimal Media Routeing;

– Explicit Congestion Notification support;

– Emergency Call;

– IMS end-to-end media plane security;

– Access Transfer procedures with media anchored in ATGW;

– Multimedia Priority Service;

– RTP Header extension to signal Coordination of Video Orientation;

– Generic image attribute;

– Interactive Connectivity Establishment;

– Video Region of Interest (ROI) ;

– RTP-level pause and resume functionality ; and

– "RTCP Codec Control Commands and Indications"