[VoiceOps] VoLTE vs UMA (GAN)

[Victor Chukalovskiy]

Good day, would it be valid to compare VoLTE vs UMA/GAN, and if so what 
would be the differences?

My 10,000 feet view is that UMA/GAN is an older techology for switching 
voice between WiFi data channel and an actual GSM/3G voice channel.
Whereas VoLTE is a fairly recent spec and it switches between WiFi and 
LTE, both being IP data channels, sort of like your 'eth0' and 'eth1'.

I guess both integrate heavily into core mobile network and into headset 
OS, and would offer similar user experience? Both can be leveraged by 
either MNO or MVNO, but not by some sort of over-the-top app?

Many thanks!
-Victor