Subject: Re: FW: [SIP] wg last call on reliable provisional responses

From: Jonathan Rosenberg <[email-masked]>
Date: Thu, 01 Jun 2000 01:03:46 -0400

"Schroeder, Tim" wrote:
> 
> James Undery writes:
> I think what is being hinted at albeit subtlety is, is the transaction ever
> going to end? (The Halting Problem.) Although I can't think of a case off
> hand where you'd want to provisionally respond to a PRACK, specifically
> allowing it is just asking for trouble between legitimate implementations.
> [...] Except it may spawn another PRACK that spawns another PRACK ad
> infinitum.

I'd still argue that this just means you have a buggy server. Reliable
provisionals are not sent "just for fun" - it is usually for a reason.
So, the case I was considering was where the first PRACK had some
special data in a provisional response that needs to be sent reliably.
This data would itself be acknowledged with a PRACK, but there is no
reason for the second PRACK to have a reliable provisional response.

That said, if no one has any applications for this, and people think
that folks will just get into trouble with it, I'll remove that.

-Jonathan R.
-- 
Jonathan D. Rosenberg                       72 Eagle Rock Ave.
Chief Scientist                             First Floor
dynamicsoft                                 East Hanover, NJ 07936
[email-masked]                     FAX:   (732) 741-4778
http://www.cs.columbia.edu/~jdrosen         PHONE: (732) 741-7244
http://www.dynamicsoft.com

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From: James Undery <[email-masked]>
Date: Thu, 01 Jun 2000 09:18:25 +0100

> reason for the second PRACK to have a reliable provisional response.

My argument is the two entities aren't buggy because, you may decide the second
PRACK can't contain data that requires a reliable provisional response, but how
do you know some application won't. Personally I can't see the need for
provisional responses to a PRACK except 100 (which can't be sent reliably anyway)
and you know the final response will get there (or else you've bigger problems
anyway).

> that folks will just get into trouble with it, I'll remove that.

James Undery