1 Scope

23.2373GPPIP Multimedia Subsystem (IMS) Service ContinuityRelease 17Stage 2TS

The present document specifies the architectural requirements and procedures for delivery of IMS Service Continuity.

TS 23.206 [3] is migrated to this specification.

The scope of the specification includes:

– Access Transfer related functionality:

– PS-CS Access Transfer;

– PS-PS Access Transfer;

– PS-PS Access Transfer in conjunction with PS-CS Access Transfer;

– Adding and/or removing media flows to support service;

. MSC Server assisted mid-call feature;

– SRVCC session transfer of IMS emergency session;

– DRVCC session transfer of IMS emergency session.

– Inter‑UE Transfer related functionality:

– Establishment and release of a Collaborative Session;

– Addition of media flows to, modification of media flows in, and release of media flows from a Collaborative Session;

– Transfer of media flows from one UE to another;

– Transfer of the Collaborative Session Control with or without transfer of media flows;

– Transfer of all media flows to a target UE without establishing a Collaborative Session;

– Session discovery;

– Inter-UE Transfer initiated by the target UE or by the SCC AS;

– Replication of media flows by means of Inter-UE Transfer procedures;

– Authorization and other aspects to support Inter-UE Transfer across multiple IMS subscriptions.

The solution is restricted to service continuity using IMS procedures, i.e. mobility mechanisms on the IP-CAN level are not within the scope of this specification.