WebRTC

What is it and Why should you care?

PyWeb-IL #90
By: Benny Daon

About Me

  • Been to PyWeb-IL #1
  • 30 years of coding in the shell
  • Inspected a lot of packets
  • Last year working on a WebRTC based terminal

The Itch:

Touching the terminal

and nothing happens

The Solution

Why WebRTC

  • Real time
  • Secure
  • Rate Controlled
  • Supported by all browsers
  • Open source projects to start from:
    • aiortc
    • janus
    • pion/webrtc
    • ...
       

WebRTC History

  • 2010 - Google buys GIPS
     
  • 2011 - W3C publishes first draft
     
  • 2014 - Google hangouts uses WebRTC
     
  • 2017 - WebRTC 1.0 becomes a candidate recommendation
     
  • 2021 - WebRTC 1.0 becomes a recommendation

WebRTC is an incomplete API

A bulky API covering a mesh

of network protocols while

leaving signaling to magic

The Browser Parts

The browser part

By: Princiya

The Protocol Monster

By: Sean Dubois

Batteries Included

  • PeerConnection
    • addTrack/onTrack
    • createDataChannel/onDataChannel
    • getStats
    • ...

Interactive Connectivity Establishments

By: Andrew Prokov

Initiator Code

pc = new RTCPeerConnection({ 
       iceServers: [ { urls: iceServers }],
       certificates: myCert
})
pc.addTrack(track, stream...)
pc.createDataChannel('label')
pc.createOffer(offerOptions)
.then(desc => pc.setLocalDescription(desc))
pc.onicecandidate = signalMagic

Tracking State

pc.onconnectionstatechanged(e => {
  switch(pc.connectionState) {
    case "connected":
      // The connection has become fully
      // connected
    case "disconnected":
    case "failed":
      // One or more transports has terminated
      // unexpectedly or in an error
    case "closed":
      // The connection has been closed
})

Accepting Offers

onOffer(offer) {
    let sd = new RTCSessionDescription(offer)
    pc.setRemoteDescription(sd)
}

The story of RTOMax

 RFC 4960: Stream Control Transmission Protocol

The computation and management of RTO in SCTP follow closely how TCP manages its retransmission timer.

 RFC 4960: Stream Control Transmission Protocol

  C7)  A maximum value may be placed on RTO provided it is at least RTO.max seconds.

Further Reading

WebRTC

By Benny Daon

Made with Slides.com

WebRTC

What is it and why should you care?

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