Sometimes due to coverage hole issue in the LTE network, the ongoing VoLTE is continued to UE by using the CS network like GSM network. This is known as SRVCC (Single Radio Voice Call continuity). What messages are exchanged between network nodes when UE moves from LTE to GSM ?
Is it mandatory to establish a separate default bearer to exchange IMS signaling messages between UE and IMS network nodes ? Can't internet default bearer be used for the same ?
There are two scenarios of VoLTE call. 1. Originator and Receiver both are connected in LTE network. 2. Either one of them is not in the LTE coverage .
How the signalling messages flow between originator and receiver for both are scenarios ?
