ETSI - TS 123 228
Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); LTE; IP Multimedia Subsystem (IMS); Stage 2
|Publication Date:||1 March 2022|
This document defines the stage-2 service description for the IP Multimedia Core Network Subsystem (IMS), which includes the elements necessary to support IP Multimedia (IM) services. ITU-T Recommendation I.130  describes a three-stage method for characterisation of telecommunication services, and ITU-T Recommendation Q.65  defines stage 2 of the method.
This document does not cover the Access Network functionality except as they relate to provision of IM services, these aspects are covered in the normative Annex E for these accesses.
This document identifies the mechanisms to enable support for IP multimedia applications. In order to align IP multimedia applications wherever possible with non-3GPP IP applications, the general approach is to adopt non-3GPP specific IP based solutions.