> -----Original Message-----
> From: Francois Audet [mailto:[EMAIL PROTECTED] 
> Sent: Monday, February 04, 2008 9:56 AM
> To: Dan Wing; Cullen Jennings; Bruce Lowekamp
> Cc: P2PSIP Mailing List
> Subject: RE: [P2PSIP] Choice of STUN peer or TURN peer
> 
> 
> 
> > -----Original Message-----
> > From: Dan Wing [mailto:[EMAIL PROTECTED] 
> > Sent: Saturday, February 02, 2008 00:32
> > To: Audet, Francois (SC100:3055); 'Cullen Jennings'; 'Bruce 
> Lowekamp'
> > Cc: 'P2PSIP Mailing List'
> > Subject: RE: [P2PSIP] Choice of STUN peer or TURN peer
> > 
> > Reports indicate that roughly 25% of NATs would block such 
> > incoming packets. 
> > 
> > This means that a TURN client, trying to use a random TURN 
> > server's transport address that is published into the p2p 
> > overlay, would get a 75% success rate.
> > If the TURN client tried two TURN servers it would get a 
> > success rate of 87.5%, and so on, up to trying 11 TURN 
> > servers to get a success rate of 99.9%.
> > 
> > 
> > Those success rates include no calculations about TURN 
> > servers that have crashed, had their p2p-TURN application 
> > terminated, had their NATs crash or otherwise lose state, etc.
> 
> And?
> 
> That doesn't seem so bad to me. When a peers goes live 
> (attempts to connect), it
> would then try to find a working STUN/TURN server. After a 
> few attempts, it is
> likely to find a working one. A success of 87.5% after 2 
> tries seems very good to me.

Ok.  I guess it depends on if it's going to find a working
TURN server upon initialization of the application, or if it
waits until it needs to make an active call.

> Also, the alternative is that the servers themselves do a lot 
> of self-assestment which takes some time.

A self-qualification procedure won't take more than a few
seconds to determine if you're behind a non-p2p-friendly
NAT and thus cannot be a TURN server.  And that self-
qualification only needs to happen upon initialization
of the application or aquiring a new WAN address (both
of which indicate, with high likelyhood, that you might
be behind a different NAT).

> I'm also thinking that if somehow we could make the process 
> of being a STUN/TURN server
> and discovering others/joining the overlap mandatory, then we 
> wouldn't have the problem
> that everybody would opt out of being used as a STUN or TURN server.
> 
> (By mandatory, I don't mean "the spec says it's mandatory: I 
> mean the procedures would be
> intertwined enough that it would not be possible, or at least 
> very difficult, to
> disable the STUN and TURN server).

-d


> Just thinking out loud...

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