What is the maximum size of webRTC data channel messages?

Question

I'm experimenting with webRTC and it seems that there's an arbitrary limit to how many bytes can be sent in each message. This guy whose example I used chose a limit of 100 (plus some) bytes. In my tests it seems to be close to 200 bytes. However from reading on TCP and UDP those protocols support packages of up to around 65kb and even when taking the MTU for different types of networks into account it should still be a lot more space available than ~200 bytes.

The only source I've found that mentions a hard limit is this WebRTC Data Channel Protocol draft but it only says TBD.

So my questions are:

1. if there's any source that specifies the current message size limit in any browser?
2. if I can assume that the limit is always the same, and if not if there's any way my app can be made aware of the limit?

Answer 1

The sharefest project found a way around the rate throttling - you can modify the outgoing offer to change the bandwidth setting (per http://www.ietf.org/rfc/rfc2327.txt)

Details here: https://github.com/Peer5/ShareFest/blob/master/public/js/peerConnectionImplChrome.js#L201

From my own experience you're still limited to ~800 bytes per message.