I'm wondering why telcos don't use SIP (and something with sane APIs for the data / control plane) or something internally? Maybe for peering with other networks, too.
This is the dirty truth. What we think of as telco is evolving. Telco is desperately trying not to be a “dumb pipe”, but that’s exactly what the internet wants the base layer to be. When the base layer is opinionated, bad things happen, like net neutrality.
What we want is unbiased fast networks that route data indiscriminately as long as it is correctly formatted and sent from a known address. That’s it.
Everything else is just vanity.
Totally agree with the what we want part.
Not wrappers. VoLTE is literally SIP with extensions. And VoWiFi is literally VoLTE over IPSec/IKE with EAP auth, so SIP over IPSec. Really just bog standard stuffs.
> – pretty complex, but still using modern tech
Not sure about "modern", but yeah pretty much every actor uses SIP one way or another. It does have a few old stuff (one SIP extension of VoLTE is to allow SIP-negotiated IPSec tunnel. For HMAC it supports md5-96 and sha1-96 and that's all.), but nothing that makes you scream of over-complication.
WhatsApp really applied a ton of pressure to telcos and changed the game. Do you remember they an international sms in the US was $.60 per message before whatsapp?