2011/7/28 Couret Tabt <[email protected]>: > That is to say, > if we do NOT use B2BUA, > we need much time to receive ACK for 200 OK, > especially in Internet. > Then, we have re-transmitting of 200 OK. > > The solution of that is B2BUA. > Accordingly, most SIP system ( though Internet) > adopt B2BUA. > > Am I right?
The reasons for using a B2BUA are not "avoiding 200 retransmission". Retransmissions indeed exist and are 100% covered by RFC 3261 so they MUST NOT be a problem. B2BUA are used to build like-PBX services and so. Also, they don't "solve retransmissions" always, as typically they send the ACK (for a 200) in leg B after the ACK arrived from leg A. So the callee could send 200 retransmissions until it receives the ACK. In short, I suggest you to forget that reasoning. Regards. -- Iñaki Baz Castillo <[email protected]> _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
