In a previous LTE University blog, the network based T-ADS was discussed. Clause 5.3.1 of TS 23.292 discusses the UE T-ADS in which the network provides the UE the option to select the terminating access network domain which will be used for the delivery of a VoLTE call to the UE.
Clause 126.96.36.199.2 of TS 23.292 discusses how the SCC AS, (Service Centralization and Continuity Application Server), determines the access network for call delivery, (please refer to the figure below):
- There are 2 alternatives for the SCC AS to choose from when selecting a T-ADS:
The following figure subset is copied from TS 23.292.
"Release 10 41 V10.5.0 (2012-03)
Figure 188.8.131.52.2-1: ICS UE Terminations with CS media information flows using Gm reference point when using an MSC Server enhanced for ICS”