I assume, INVITE have SDP (i.e. Offer). And 183+SDP have some matching Answer for related offer. With above assumption,
"> > A sending INVITE to B but does not contain Require:100REL. Switch > > forwards Invite to B but has Require:100REL." [AV]-->> If switch is adding Require-100-REL, in that case, I am assuming, that is not plain switch. It is B2BUA, which essentially need to maintain dialogue-state for both the transactions. "> > Then A sends 200OK which Switch does not forward to A." [AV] --> Firstly , I assumed, it is B who is sending 200-OK. Secondly, if switch is not forwarding 200-OK, towards A, I just want to know, if switch is sending PRACK towards B or not ? And is B replying with 200-PRACK for that or not ? If switch is neither sending PRACK nor forwarding 200-OK, you must check with the coder, who have written the code for your stack. It looks to be messy state-machine-implementation. Thanks Abhishek On Fri, Nov 30, 2018 at 8:15 AM Dale R. Worley <wor...@ariadne.com> wrote: > > Abhishek <abhishek.pha...@gmail.com> writes: > > A --> Switch --> B > > All 3 nodes connected with SIP connectivity. > > > A sending INVITE to B but does not contain Require:100REL. Switch > > forwards Invite to B but has Require:100REL. > > > B responds with 180 without SDP, Switch forwards the same to A. B then > > sends 183+SDP, which switch sends to A. Then A sends 200OK which > -----------------------------------------------^ > I assume you mean "B" here. > > > Switch does not forward to A. B sends 200OK multiple times as per > > standard and Switch disconnects session at both the ends with SIP > > cause code 500. > > > > Seeking reason for such behaviour. > > It appears that Switch does not recognize the 200 as being part of the > dialog. There are innumerable reasons why this might happen. It is > hard for us to provide any help if you do not provide the INVITE (from > Switch to B) and the 200 (from B to Switch) for some example dialog. > > Dale > _______________________________________________ > Sip-implementors mailing list > Sip-implementors@lists.cs.columbia.edu > https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
