See below. > -----Original Message----- > From: [email protected] [mailto:sip- > [email protected]] On Behalf Of kaiduan xie > Sent: Friday, December 12, 2008 6:28 PM > To: [email protected] > Subject: [Sip-implementors] PRAC/B2BUA > > Hi, all, > > An inter-operation problem is encountered, the scenario is, > > UA 1 B2BUA GW > | INVITE-1 | | > |-------------------->| INVITE-2 | > | |----------------------->| > | | 183-3 | > | |<----------------------| > | 183-4 | | > |<--------------------| 183-5 | > | |<----------------------| > > INVITE-1 does not have SDP, and no Supported header. > INVITE-2 does not have SDP, but INVITE-2 has Supported header with > 100rel. > 183-3 has SDP, and Required header with 100rel. 183-3 is re- > transmitted in 183-5. I omits further retransmission. > 183-4 has SDP, but no Required header. > > The call fails. > > My question is: is legal for B2BUA to put Supported header with 100rel > if UA1 indicates that it does not support 100rel? I think B2BUA is > wrong in this case.
[Neelakantan Balasubramanian] B2BUA can provide different behavior on two legs of the call. There is no requirement on what B2BUA should do, as for UA1, the B2BUA is the UAS. There is no 100rel supported on this leg of the call. For GW, the B2BUA is the UAC. In this leg 100rel is supported. So, the B2BUA should handle retransmits of 183, send the PRACK for each provisional responses. [Neelakantan Balasubramanian] > > In the above picture, B2BUA is from a very big company :) [Neelakantan Balasubramanian] You should talk with the vendor. > > What is your point? > > Thanks > > kaiduan > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
