IP Multimedia Subsystem (IMS) Centralized Services (ICS) protocol via I1 interface
The present document describes the I1 interface between IMS Centralized Services (ICS) UE and Service Centralization and Continuity (SCC) Application Server (AS).
This specification defines a new application layer protocol over I1 interface, specifies the interaction between the ICS UE and the SCC AS including session control procedures and supplementary services control procedures.
The protocol is intended to be independent of the transport-layer protocol used so it can be applied to a number of technologies that need different transport-layer protocols.
The overall ICS architecture is specified in 3GPP TS 23.292 [2].
The procedures for delivery of IMS Service Continuity that do not use the I1 protocol are specified in the document 3GPP TS 24.237 [13].
The present document is applicable to User Equipment (UE) and Application Servers (AS) which are intended to support the IMS centralized services.