The sequence of processing a received message at a SIP UA ia to identify the call, then the dialog within the call and then the transaction within the dialog. If the call is found, then an existing dialog must be found. If the from-tag is changed, that would not occur. The UA should reject the INVITE.
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Scott Lawrence Sent: Wednesday, October 29, 2008 11:39 AM To: KASTURI Narayanan (kasnaray) Cc: sip-implementors@lists.cs.columbia.edu Subject: Re: [Sip-implementors] Call-id Use ( Re-use/Misuse) On Wed, 2008-10-29 at 08:07 -0700, KASTURI Narayanan (kasnaray) wrote: > Hi , > > I have a question on a specific behavior seen with a Proxy, the > behavior is as follows. > > UAC Proxy > |---Invite(req-URI:A, callid:1, Ftag=1)----->| > | | <----Invite(URI:B, > |callid:1,ftag=2)---------| > > And the Proxy Record-Routes as well retaining the Original Contact. > > In this specific case the UAC on seeing a call-id which it generated > with a different From Tag is failing the Invite Request. > > Question is whether it is a correct behavior on the Proxy to change > the > >From Tag retaining the same call-id in the above case. No. It is not acting as a proxy if it's messing with the tags. > I would also like opinion on what shld be the behavior of UAC in this > case. The UAC is assuming that Call-id is globally unique and is able > to detect that this call-id belongs to itself and since the From tag > is not matching with what it generated it is failing the request. Do you expect to be able to call yourself (which appears to be what's happening above)? If so, you shouldn't care and should accept the call. You can't know that the call didn't go through a B2BUA that changed only the tag and not the callid (bad practice, but it happens) - that looks like what you've got. _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
