[SR-Users] sipp to kamailio doesn't match ACK

JR Richardson jmr.richardson at gmail.com
Wed Jun 16 14:55:04 CEST 2010


> Date: Tue, 15 Jun 2010 16:57:37 -0400
> From: Alex Balashov <abalashov at evaristesys.com>
> Subject: Re: [SR-Users] sipp to kamailio doesn't match ACK
> To: sr-users at lists.sip-router.org
> Message-ID: <4C17E941.4020506 at evaristesys.com>
> Content-Type: text/plain; charset=UTF-8; format=flowed
> 
> 1) AFAIK, the Record-Route/Route headers are used by TM for maintaining
> transaction state, unless you are relying on the 'dialog' module's "fast
> matching" cookies, which are identifiers that get placed as a URI
> parameter into the Record-Route header so that it is not necessary to
> match the message by more conventional means (Via/branch, Call-ID, tags,
> etc.)
> 
> 2) ACK is a separate transaction;  every request and reply sequence is a
> transaction.  So, if you're trying to match it to an existing INVITE
> transaction, for instance, that won't happen.
> 
> t_check_trans() has special behaviour for ACKs, depending on whether
> they're end-to-end ACKs or ACKs for negative replies to existing
> transactions:
> 
> http://www.kamailio.org/docs/modules/3.0.x/modules/tm.html#t_check_trans
> 
> Are you sure that you're using it, or its newer variant,
> t_lookup_request(), correctly?
> 
> 3) You are, nevertheless, correct that the ACK should contain the RR
> header:
> 
>     The UAC core MUST generate an ACK request for each 2xx received from
>     the transaction layer.  The header fields of the ACK are constructed
>     in the same way as for any request sent within a dialog (see Section
>     12) with the exception of the CSeq and the header fields related to
>     authentication.
> 
> -- Alex
> 
Thanks for the feedback Alex.
 
JR




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