Hi Gang I am aware, this is a generic SIP question, not strictly related to Kamailio. But we are experiencing a strange issue with a 3CX PBX (and we use Kamailio as VSP)
Yes, I have read: https://datatracker.ietf.org/doc/html/rfc3261#section-8.1.1.5 https://datatracker.ietf.org/doc/html/rfc3261#section-12.2.1.1 But I still have a question: Are cseq number independent for each side, or has the B side to increment the last cseq seen from the A side on a new request? Is this a VALID example? Initial Invite A=>B A=>B INVITE: cseq 5 INVITE A<=B 100 Trying: cseq 5 INVITE A<=B 180 Ringing: cseq 5 INVITE A<=B 200 OK: cseq 5 INVITE - trancation ended A<=B Re-INVITE: cseq 1 A=>B 200 OK: cseq 1 - transaction ended A=>B BYE: cseq 6 BYE A<=B 200 OK: cseq 6 BYE - transaction ended Here A started with cseq 5 and increased to cseq 6 for the next transaction. B started with cseq 1 which is lower than what A started with. So both side use a different starting point, and each side increments their cseq by one independently of what the other side told. Or is this not allowed and B should have sent the Re-Invite with cseq 2? What about this example (which is the one we see failing) with nested transactions? A=>B INVITE: cseq 1 INVITE A<=B 100 Trying: cseq 1 INVITE A<=B 180 Ringing: cseq 1 INVITE A<=B UPDATE: cseq 1 UPDATE A=>B 500 Server Error: cseq 1 UPDATE Looking at logs on PBX A seems to indicate it detected a problem with the sequence number in the UPDATE message. So what is the linkely cause? * Two concurrent transactions with same sequence number from different sides not allowed by some RFC (if so, which one?) * Each side has to take care to start every new transaction with a higher sequence number as the other side? * PBX buggy? Mit freundlichen Grüssen -Benoît Panizzon- -- I m p r o W a r e A G - Leiter Commerce Kunden ______________________________________________________ Zurlindenstrasse 29 Tel +41 61 826 93 00 CH-4133 Pratteln Fax +41 61 826 93 01 Schweiz Web http://www.imp.ch ______________________________________________________ __________________________________________________________ Kamailio - Users Mailing List - Non Commercial Discussions -- [email protected] To unsubscribe send an email to [email protected] Important: keep the mailing list in the recipients, do not reply only to the sender!
