Re: [Sip] Interesting problem with PRACK and resent INVITEs

Jeroen van Bemmel <jbemmel@zonnet.nl> Fri, 18 January 2008 08:02 UTC

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Date: Fri, 18 Jan 2008 09:02:12 +0100
From: Jeroen van Bemmel <jbemmel@zonnet.nl>
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To: Christer Holmberg <christer.holmberg@ericsson.com>
Subject: Re: [Sip] Interesting problem with PRACK and resent INVITEs
References: <200801172023.m0HKNRNa008780@dragon.ariadne.com> <478FFED9.7080307@cisco.com> <CA9998CD4A020D418654FCDEF4E707DF041F5175@esealmw113.eemea.ericsson.se> <4790547E.8000009@zonnet.nl> <CA9998CD4A020D418654FCDEF4E707DF041F53A6@esealmw113.eemea.ericsson.se>
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Christer,
>> .
>>
>>
>> Regarding from tags there is no explicit text, but 22.2 says:
>>
>> When a UAC resubmits a request with its credentials after receiving a
>> 401 (Unauthorized) or 407 (Proxy Authentication Required) response,
>> it MUST increment the CSeq header field value as it would normally
>> when sending an updated request.
>>     
>
> So, I guess that means that the second INVITE in Dale's example should
> have Cseq => 3.

I interpreted this as "MUST increment (relative to the INVITE being 
challenged)". I guess for initial INVITEs the minimal requirement is 
that the CSeq be different, else merged request detection (8.2.2.2) 
could kick in and prevent the call from succeeding. So both 2 or 3 are 
valid, the text is ambiguous

Regards,
Jeroen


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