SIP on the Web

OverSIP + jsSIP: SIP over WebSocket

Introduction

• The aim of this presentation is to show the SIP protocol working within a web browser and interoperating with any SIP network.
• After some slides describing the used technology there is a signaling flowchart and a video showing a real implementation.
• This is SIP on the Web. Enjoy.

WebSocket

• RFC 6455 "The WebSocket Protocol".
• Two-way realtime communication between web browser and server for carrying application data.
  • Bye bye HTTP long polling and Comet.
• Managed by JavaScript: WebSocket API.
• WebSocket is just a transport layer.
• The site admin decides the message format (AKA "WebSocket subprotocol") carried on top of it.
  • That can be a custom chat protocol in JSON, or...

SIP over WebSocket

• draft-ietf-sipcore-sip-websocket.
• A WebSocket subprotocol for a new transport in SIP.
• SIP messages are carried on top of a WebSocket connection.
• Requirements:
  • SIP stack written in JavaScript.
  • SIP proxy/server implementing WebSocket transport.
• No protocols gateway here! This is not "SIP to/from WebSocket", this is pure SIP!
• Just covers the signaling component. For media... hello WebRTC! :)

OverSIP (www.oversip.net)

• SIP proxy implementing UDP, TCP, TLS and WebSocket transports.
• Fully asynchronous event-based design, never block!
• It behaves as a SIP Outbound Edge Proxy (as defined in RFC 5626).
• Web browsers (or any WebSocket client) establish a WebSocket connection with OverSIP.
  • ... and pure SIP messages exchange begins (draft-ietf-sipcore-sip-websocket).
• No changes to SIP protocol, no need for a special B2BUA, no protocol conversion.
  • ... but just pure SIP.

jsSIP (www.jssip.net)

• JavaScript library implementing a full SIP stack.
  • Audio/video calls (WebRTC), instant messaging and presence.
  • Lightweight (~160 KB).
  • Easy to use and powerful user API.
  • Works with OverSIP, Kamailio and Asterisk servers.
• Uses WebSocket for sending/receiving SIP messages.
  • ... again draft-ietf-sipcore-sip-websocket.
• SIP intelligence in the endpoint!

Real Demo

• Next slides show the network topology of a working environment.
• And then a video showing it in action!

Video "SIP on the Web"

• See OverSIP + jsSIP in action, download the video:
  • Ogg Vorbis video (17 MB).
  • MP4 video (5.7 MB).
  • AVI video (46 MB).
• Or watch it in Youtube:
• http://www.youtube.com/watch?v=qfFlK1KyF6Q.
• Real screenshot of JsSIP with audio+video (webcam): screenshot.