Chrome Stable ice backward compatibility issue

[Yu Bao]

I'm testing Chrome stable (23.0.1271.64 m) and tried to make a call to it use google ice instead of RFC5245-compliant ice. It seems backward compatibility is only supported for remote description, but not for local description. 

For example in following scenario:

  

1. Send a legacy SDP offer to Chrome, in which session version=0, no ice-option. This is correctly processed if feed it to setRemoteDescription, the produced SDP answer has session version=0, no ice-option.

2. Apply the SDP answer in setLocalDescription, return error when trying to match the ice protocol in offer an answer. Offer is recognized as using the google ice protocol, answer is recognized as using RFC5245.

Referred to the Chromium code and seems the problem is this: Transport description is created to use rfc5245 compliant ice by default, only when the backward compatibility procedure is applied would it be changed to use google-ice. However, the backward compatibility procedure is not invoked for setLocalDescription.

Found a workaround later:

1. Construct the SDP offer to use session version=2, add ice-option:google-ice

2. Modify the SDP answer before setLocalDescroption, add ice-option:google-ice

This sets both offer and answer to hybrid mode, in which case Chrome picks google-ice by default, thus my google-ice-only-proxy is able to talk to the browser.

Don't know if this is a bug and will be fixed in v24?

 

[Vikas]

Thanks for the feedback. We will look into it. I have filed an issue
in the tracker. Please refer to issue 1098.

/Vikas

[Brave Yao]

We had added the back compatibility for issue 973&1074 and it should work for your case. It would be in Canary soon and would be merged to M24 as well. Please stay tuned!