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Not enough detail here, but I'm surprised when I see the terms "voice" and "TCP" together. Do they use TCP to set up the call, then UDP to handle the audio? Ed

Not enough detail here, but I'm surprised when I see the terms "voice" and "TCP" together. Do they use TCP to set up the call, then UDP to handle the audio? Edit: Yep, they use UDP for the audio: https://github.com/WhisperSystems/RedPhone/wiki/Signaling-Protocol https://github.com/WhisperSystems/RedPhone/wiki/Signaling-Pr...

bradleyland 14y ago
With the traditional VoIP stacks, yes. There are two components to making phone calls: messaging and media. The messaging part sets up and tears down calls. The media part passes the audio. I'd imagine they're doing the same.
- dkhenry 14y ago
  but typically you use something that can have at least some intelegent behaviour like RTP not UDP. Why did they choose that when literally every other pure VoIP service uses RTP ?
  - moxie 14y ago
    We use RTP (actually SRTP and ZRTP), but the transport is still UDP.