How many channels does WebRTC have and what transports are used?

2
votes

I felt that WebRTC has 2 channels:

  1. Signalling channel (data transported via secured TCP)
  2. Media channel (data trasnported via DTLS or SRTP)

Are there more channels to this? Namely "DataChannel" -- probably used for file & chat sharing?

If there is, how is it different from the traditional VOIP media channel and what protocol does it use?

1
javascriptwebrtcp2pdtlsrtcdatachannel

1 Answers

2
votes

WebRTC Data Channels are indeed designed to transfer raw data, either reliably or not. Note that you can establish multiple Data Channels over a single Peer Connection, they'll run in parallel.

The network stack involved is SCTP over DTLS. The main difference compared to media is that it implements flow and congestion control, to allow for elastic traffic, a behavior similar to TCP.