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