Re: [tram] Points that should be clarified in STUN-bis and TURN-bis

Paul Kyzivat <> Mon, 10 February 2014 16:54 UTC

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Date: Mon, 10 Feb 2014 11:54:42 -0500
From: Paul Kyzivat <>
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Subject: Re: [tram] Points that should be clarified in STUN-bis and TURN-bis
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On 2/10/14 11:37 AM, Simon Perreault wrote:
> Le 2014-02-10 10:18, Paul Kyzivat a écrit :
>>> Option 3 means you don't have to keep backward compatibility around
>>> forever. Practically, all TURN-bis servers would be backward compatible
>>> from day 1. Then as time passes the client population would gradually
>>> migrate to TURN-bis. When the non-TURN-bis client population becomes too
>>> small to justify the cost of backward compatibility, you can throw
>>> compat away. For example, if you start a new implementation of STUN
>>> today, it could be possible to ignore STUNv1 (depending on your target
>>> market), and thus make the implementation smaller, simpler, easier to
>>> test, and faster to develop.
>> It would be more of an issue of there was a real issue if there was a
>> significant cost to supporting backward compatibility. But IIRC, the
>> only cost for backward compatibility here is filling in a standard
>> default if the parameter is missing.
> You are correct in this particular instance, of course. In general,
> things may be different.

My philosophy is to start out assuming backward compatibility.
If something is found that makes that much of a burden, then discuss 
what to do about it.

>> The consequence of not requiring backward compatibility is that a
>> developer does exactly as you describe above - ignore STUNv1
>> compatibility in his server because he thinks his target market won't
>> need it. Then it turns out that there is a STUNv1 client. And that
>> client just fails because of this.
> Correct. And then either 1) the developer realizes that this STUNv1
> client is important enough to warrant additional development, or 2) the
> developer says "tough luck" to the client, and the client's only
> recourse it to upgrade to STUNv2. IMHO, that's exactly the kind of
> thinking that we want to encourage! :)

If the new thing isn't compatible with TURNv1 then call it something 
different, so that the process of discovering a TURN server only gets 
the appropriate kind.

> Anyway, we're just philosophizing, this has no practical impact on
> anything at this point.