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

Paul Kyzivat <pkyzivat@alum.mit.edu> Mon, 10 February 2014 15:18 UTC

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Date: Mon, 10 Feb 2014 10:18:28 -0500
From: Paul Kyzivat <pkyzivat@alum.mit.edu>
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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 9:27 AM, Simon Perreault wrote:
> Le 2014-02-09 21:44, Paul Kyzivat a écrit :
>> IMO only (1) makes sense. With the others, migration becomes a
>> nightmare. No flag days!
>
> Option 1 means there is no migration at all. You're stuck with the past
> forever.
>
> 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.

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.

	Thanks,
	Paul