Can someone please share the call flow or network diagram which show how an IMS call establishes between UE and the network ?
I am assuming one thing that both sides have IMS and the call is being obviously on LTE.
This PDF has the call flow. http://www.eventhelix.com/ims/ims_to_ims_call/ims_to_ims_call.pdf
If you want some other call flows please go through this webpage it would give you all important call flows.
http://www.eventhelix.com/ims/
Does LTE network send any specific message to UE so that UE come to know network supports IMS call ? Or Does the LTE network broadcast information such as "it does not support IMS call" ?