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What I want is, basically, to create a connection between two different computers on same local network. But i want to do this by computers' local IP's. (like 192.168.2.23 etc)

This must be a totally local connection. no TURN or STUN Servers. I am not sure if this is possible. Because there are not much documentation/example/information about WebRTC.

So, how can I create a connection from my computer to another one just passing its local IP as parameter?

Update: To be more clear; imagine there is an html page contains some code that activates my camera and audio services. and another -almost same- page is open in other computer. Waiting a connection request... And there is a textbox in my page to type an IP belongs to other computer on my local network. type 192.168.2.xx and bingo! i have connection between me and other computer.

I want this process as IP based, because there may be more than 2 devices on the network. And all of them are possible devices to create connection. So i need to reach them by their IP's.

Any example code or explanation would be great! even if it tells that this is not possible.

Thanks

Werner Henze
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alioguzhan
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3 Answers3

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Users usually sit behind NATs; that's why ICE concept implemented in WebRTC.

If both users are sitting behind same NAT; you can skip ICE servers by passing "NULL" parameter value over "RTCPeerConnection" constructor:

var peer = new [webkit|moz]RTCPeerConnection ( null );

Now, browser will use "host" candidates, also known as "local" candidates.

Muaz Khan
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    So how do two computers recognise each other? imagine there 7 computers on a local network. – alioguzhan Nov 29 '13 at 15:25
  • @alix The IP's are unique, as long as all 7 computers are on the same network, the signalling server will coordinate the establishment of SDP between the computers after which they will now be able to "recognise each other" – Damilola Olowookere Jul 04 '16 at 23:55
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Peer discovery is a vital part in any WebRTC application. It's an expensive term for saying: "Hi, I'm computer 4 and I want to talk to you!". See it as calling a friend over the phone. You need to dial his number first. This part is not defined in the WebRTC standards. You need to implement this logic in your application. Once you know who you want to call, you need a way of exchanging vital information. This is called signaling, like flo850 put in his answer. Signaling is needed before any peer-to-peer connection can be set up.

To come up with an idea for your use case of 7 devices in a LAN.

If you have these devices connected to for example a WebSockets server and are in the same channel.

The WebSockets server can be written to route messages to specific receivers. Devices connected to the channel often are identified with some kind of ID, imagine you use the device's IP. When you want to talk to computer 4 with IP 192.168.0.4 you send the exchange messages (signaling) on the channel to the receiver with ID, the IP of the device you want to connect with. How to send the signaling (offer, answer) is described here with example code.

Hope this helps

Gnagy
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    This is the explanation i need. Bad news but i am OK with this. At least,anymore, i know what i CAN'T do with webRTC. Thank you so much. – alioguzhan Dec 09 '13 at 00:19
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you still need a signaling server. During the ICE candidate search, your clients will exchange their local ip through this signaling server

flo850
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