What is "best" depends on your situation... Certainly the X-PRO should be fixed if it is using the incoming to-tag as its outgoing from-tag.
On the other hand, if the B2BUA considers a 200 response with the to- and from-tags are the same to be proper, it should be willing to accept requests (e.g., BYE) from the remote UA. Dale ________________________________________ From: Tarun2 Gupta [[email protected]] Sent: Tuesday, June 05, 2012 7:19 AM To: Worley, Dale R (Dale); [email protected] Subject: RE: [Sip-implementors] Same tags in To and From headers in 200 OK response The UA2 in question here is X-PRO build 1082. So what’s the best solution - Fix in UA2 or fix in B2BUA? Regards, Tarun Gupta Aricent -----Original Message----- From: Worley, Dale R (Dale) [mailto:[email protected]] Sent: Monday, June 04, 2012 8:21 PM To: Tarun2 Gupta; [email protected] Subject: RE: [Sip-implementors] Same tags in To and From headers in 200 OK response > From: Tarun2 Gupta [[email protected]] > > Hi All > > Consider the following scenario: > > > UA 1 B2BUA UA2 > Invite (From tag F1) > ---------------------------------> > Invite (From tag F2) > ----------------------------------> > 200 OK (From tag F2, To tag F2) > <--------------------------------- > > As per Section 19.3 of RFC 3261, > "When a tag is generated by a UA for insertion into a request or > response, it MUST be globally unique and cryptographically random with > at least 32 bits of randomness" If the B2BUA accepts the 200 with F2 as both from- and to-tag, then it must accept the BYE. But more importantly, why is UA2 generating such a 200? The chance is less than 2^(-32) that the two tags would be the same if the to-tag was generated according to RFC 3261. It is almost certain that UA2 is malfunctioning. If that is fixed, the problem with the BYE vanishes. Dale =============================================================================== Please refer to http://www.aricent.com/legal/email_disclaimer.html for important disclosures regarding this electronic communication. =============================================================================== _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
