Re: [Sip] WGLC for draft-ietf-sip-fork-loop-fix-01.txt

Robert Sparks <> Thu, 20 April 2006 23:07 UTC

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From: Robert Sparks <>
Subject: Re: [Sip] WGLC for draft-ietf-sip-fork-loop-fix-01.txt
Date: Fri, 21 Apr 2006 08:07:11 +0900
To: "Vijay K. Gurbani" <>
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On 21-Apr-06, at 1:29 AM, Vijay K. Gurbani wrote:

> Robert Sparks wrote:
>>> Also, I am confused -- in previous bakeoffs, we have successfully  
>>> tested loop detection; so why can't we do this now?
>> Well - if you remember, we went through a lot of pain at each event
>> when we were testing new implementations of loop detection. By the
>> end of  each event, most of the people that were trying to get it
>> right got it working, but at the start, it was a mess.
> Yes, I remember those pains very well.  But most implementations
> that did the "advanced scenarios" did eventually -- after much
> configuration problems -- get it working with the set of headers
> (except the Via header) suggested in rfc3261.
>> That basically went away when we went to max-forwards because most  
>> people just took that logic out. Now that we're asking for it again,
>> we're right back to things not working.
> That's the thing that puzzles me -- rfc3261 never deprecated loop
> detection in favor of M-F.  All through until rfc3261 was released
> (June 2002) and even thereafter, we used to do the loop detection
> tests in the bakeoffs.  But I have not attended the bakeoff in the
> last couple of years, so is it the case that somewhere down the
> line we stopped doing loop detection tests in the bakeoffs
> despite it still being a MAY in rfc3261?

We still run the loop/spirals test. But for the last several years of  
almost no-one used the loop-detection concept. The vast majority of
implementations relied on max-forwards to end loops.


> Oh well...
> - vijay
> -- 
> Vijay K. Gurbani  vkg@{,,}
> Bell Laboratories, Lucent Technologies, Inc.
> 2701 Lucent Lane, Rm. 9F-546, Lisle, Illinois 60532 (USA)

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