VoWiFi: Why the ePDG is designed to be behind the PGW?

[mrajagopal]

@needoos.th

I am quoting based on experience, never seen it working anywhere.
Lot of time I have been at places where there is full wifi coverage and no network.
No one was able to reach me😁.

Interesting.

@needoos.th

AAA has an interface with PGW that possibly is to get IP assigned to UE for communication with IMS.

Other problem may be with emergency calls , you cannot locate users based on wifi connection.

Oh yeah, IP address allocation is one thing. This might be the reason ePDG is behind PGW. Convincing.

@Pritam.Nandy

Yes, VoWiFi registration fails if the UE is not registered in LTE.

@Pritam.Nandy, both should be independent enough na… my device (Vivo) is supporting both independently.

See the WiFi calling symbol beside the WiFi symbol. This is when “VoLTE HD call” is off and “WiFi calling” is alone ON.