webRTC

What is webRTC?

WebRTC (Web Realtime Communications) enables peer to peer video, audio, and data communication between two web browsers. This allows for video calling, video chat, and peer to peer file sharing entirely in the web browser, with no plugins. It is kind of javaScript library.

https://www.youtube.com/watch?v=RI5fGsEvDnI

webRTC

What You Need?

WebRTC compatible browser (chrome,opera and firefox)
supported platform (android, ios)
HTML5

How Does It Work?

WebRTC connection has 3 steps:

Step 1: Signaling: both peers connect to a signaling server (using websockets over 80/443, comet, SIP,etc..) and exchange information (about their media capabilities, public IP:port pairs when they become available, etc.)

Step 2: Discovery: Devices connected to LAN or mobile networks are not aware of their public IP (and port) where they can be reached at so they use STUN/TURN servers located on the public Internet to discover their ip:port pair (ICE candidates). In the process they punch a hole through the NAT/router which is used in step3:

Step 3: P2P connection: once the ICE candidates are exchanged through the initial signaling channel each peer is aware of each other's ip:port (and holes have been punched in NATs/routers) so a peer to peer UDP connection can be established.