A.5.1 Introduction

24.1823GPPIP Multimedia Subsystem (IMS) Customized Alerting Tones (CAT)Protocol specificationRelease 17TS

The following flows show establishment of a session between UE#1 and UE#2, using the gateway model as defined in RFC 3960 [8] to provide CAT to UE#1. The following flows are included:

– clause A.5.2 shows CAT, using the gateway model, when UE#1 and UE#2 have resources available;

– clause A.5.2A shows gateway model CAT using reINVITE request, when UE#1 and UE#2 have resources available;

– clause A.5.3 shows CAT, using the gateway model, when UE#1 does not have resources available;

– clause A.5.3A shows gateway model CAT using reINVITE request, when UE#1 does not have resources available;

– clause A.5.4 shows CAT, using the gateway model, when UE#2 does not have resources available;

– clause A.5.4A shows gateway model CAT using reINVITE request, when UE#2 does not have resources available;

– clause A.5.7 shows CAT, using the gateway model, when both UE#1 and UE#2 do not have resources available

– clause A.5.8 shows CAT with different media types during one session, using gateway model, when both UE#1 and UE#2 do not have resources available

NOTE: Flows in clauses A.5.2A, A.5.3A and A.5.4A shall apply when the originating UE will release or change the ports used from the original SDP offer during a session.

The following flows show establishment of a session between UE#1,UE#2 and UE#3, among which the UE#3 is the diverted UE for UE#2, using the gateway model as defined in RFC 3960 [8] to provide CAT to UE#1. The following flows are included:

– clause A.5.5 shows CAT signalling flow for a successful communication forwarding on no reply using the gateway model with reINVITE request, when UE#1 , UE#2 and UE#3 have resources available;