Aye understood. So in any case (minus the exceptions to the rule: CANCEL and ACK for non-2xx responses), when the cookie is present, INVITE and OPTIONS should have unique Via branch ids, including when OPTIONS pings are used in-dialog on a call. In this case, the Service Provider device is incorrectly selecting the Via branch from the OPTIONS dialog when responding to the INVITE dialog. I'll investigate that path then.
Thanks very much for your help, it's greatly appreciated. On Wed, Sep 11, 2013 at 11:25 AM, Brett Tate <br...@broadsoft.com> wrote: > RFC 3261 section 8.2.6.2: "The Via header field values in the response > MUST equal the Via header field values in the request and MUST maintain the > same ordering." > > RFC 3261 sections 8.1.1.7 and 17.2.3 discuss the Via branch magic cookie. > If cookie present, the INVITE and OPTIONS must not have the same Via > branch. If the cookie is not present, the INVITE and OPTIONS branches may > be equal; if needed, see RFC 2543 for more details when no cookie. > > > > -----Original Message----- > > From: Gio Navarrette [mailto:brutw...@gmail.com] > > Sent: Wednesday, September 11, 2013 12:01 PM > > To: sip-implementors@lists.cs.columbia.edu > > Subject: [Sip-implementors] SIP In-Dialog OPTIONS Ping Branch IDs > > > > Hi all - > > > > I've encountered an oddity that I'm not too sure how exactly it should > > be > > handled and was hoping for a second opinion. Here's the scenario: > > > > PBX --INVITE;branch=A--> Service Provider > > PBX <-- 100 Trying;branch=A -- Service Provider > > PBX <-- 183 Session Progress;branch=A-- Service Provider > > PBX --OPTIONS;branch=B--> Service Provider > > PBX <--200-OK/OPTIONS;branch=B-- Service Provider > > PBX <--200-OK/INVITE;branch=B-- Service Provider > > > > In short, during a call setup, an OPTIONS ping is generated, with the > > same > > From/To numbers as the INVITE, but with a different branch id. My > > question > > is should that branch-id be different on the OPTIONS ping out, or > > should > > that be the same as the INVITE? The service provider device is sending > > the > > 200/OK to the INVITE with the branch-id from the OPTIONS ping rather > > than > > the INVITE, which seems suspect. I've not been able to find a good lead > > in > > the RFCs yet. > > > > Any insights, thoughts, or leads are greatly appreciated. Thanks in > > advance > > for your time. > > _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
