[egwynn]

I’m curious about how this works, can you link me someplace where I can read more about it? I tried searching for “cellular over wifi” but wasn’t about to find anything promising.

EDIT: I searched harder and found “VoWiFi”. It looks like this can support SMS and is supported by iOS. TIL.

[Anunayj]

For someone more curious, I tried to learn more about this tech, and this [1] is the best resource I found about someone explaining how it works.

Essentially VoWifi connects to your ISP via a IPSec VPN using secrets derived using your sim card as a smart card, then connects to a internal SIP server and voila.

I spent a lot of time trying to connect to the IPSec server from a computer, but couldn't figure out how to get the challenge solved by my sim. Gosh I wish I could make normal calls from my computer.

1. https://worthdoingbadly.com/vowifi/

[egwynn]

Thanks for this link! This is a great explanation which clears a lot of things up to me.

[__derek__]

Bingo. My carrier offers it as Wifi Calling. It worked surprisingly well.

[stevewatson301]

https://en.wikipedia.org/wiki/Generic_Access_Network