[SR-Users] Via header branch parameter in ACK message not unique

[Daniel-Constantin Mierla]

Hello,

On 12/12/11 12:02 PM, Phillman25 Kyriacou wrote:
> Dear Daniel
>
> Thanks, this worked!
> I will inform my carrier that they are handling the ACK 200 message wrong.
> just one question: the syn_branch=0 is used for only stateless ACK 
> messages?
it is used for all stateless forwarded requests. By its nature, ACK is 
always stateless because it does not take any reply, so there is no 
dedicated transaction for it -- in other words, no matter how you send 
the ACK from config (e.g., t_relay() or forward()), it will be done 
stateless.

Cheers,
Daniel

>
> Thanks again for your assistance!
> Phillip
>
>
> On Mon, Dec 12, 2011 at 11:25 AM, Daniel-Constantin Mierla 
> <miconda at gmail.com <mailto:miconda at gmail.com>> wrote:
>
>     Hello,
>
>
>
>     On 12/12/11 8:18 AM, Phillman25 Kyriacou wrote:
>>     Dear List
>>
>>     I'm currently facing an issue with a carrier whereby they are
>>     complaining that the via header branch parameter (sip.Via.branch
>>     == "z9hG4bKcydzigwkX") in the ACK messages is not unique which
>>     results in some calls being successful and some terminating after
>>     20 seconds as their sip proxy determines it as a duplicate
>>     request. Is there a way to make the via header branch parameter
>>     in the ACK message unique across every transaction?
>     set in your config file the global parameter:
>
>     syn_branch=0
>
>     On the other hand, the behavior of the devises used by carrier is
>     completely broken. ACK can have a different path than INVITE, so
>     there should be no match done on Via branch parameter. Since it is
>     ACK for 200OK, it has to be matched for dialog. Having the RFC3261
>     cookie in the branch parameter, it has to be matched with (callid,
>     from tag, to tag).
>
>     Cheers,
>     Daniel
>
>     -- 
>     Daniel-Constantin Mierla --http://www.asipto.com
>     http://linkedin.com/in/miconda  -- http://twitter.com/miconda
>
>
>
>
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-- 
Daniel-Constantin Mierla -- http://www.asipto.com
http://linkedin.com/in/miconda -- http://twitter.com/miconda

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