Comments inline... Thanks, Nataraju A B
> -----Original Message----- > From: [EMAIL PROTECTED] [mailto:sip-implementors- > [EMAIL PROTECTED] On Behalf Of karthik > Sent: Wednesday, September 13, 2006 9:19 AM > To: [email protected] > Subject: [Sip-implementors] Query Regarding timer C > > Hi, > > I have a basic doubt regarding Timer C. > > Section 16.6 bullet 11 > > "In order to handle the case where an INVITE request never > generates a > final response, the TU uses a timer which is called timer C. Timer C > MUST be set for each client transaction when an INVITE request is > proxied. > The timer MUST be larger than 3 minutes. Section 16.7 bullet 2 > discusses how this timer is updated with provisional responses, > and > Section 16.8 discusses processing when it fires." > > From this it is clear that Timer C should be started when request > is > proxied. > > My question here is what is the use of Timer B in Transaction > Stateful > Proxies. > From my understanding once Timer B fires the transaction layer > would > destroy the > client transaction. > > Starting the Timer C after receiving the first 1xx response and > refreshing it on subsequent > provisional responses sounds fine. This is the behaviour given in > bis-05. Why has this > been changed in bis-09. > [ABN] as of this is sort of bug in 3261. Timer B would be stopped soon after 1xx response received @ UAC. Whereas the timer C serves an additional purpose. Assume the scenario, you have forwarded the 1xx response (from all of the targets) and you did not receive the final response, transaction would be up forever. If the Timer C fires, then the RC would consider that particular Client transaction timed out (408) and proceed further. If this is not performed (we don't have either Tb or Tc) then proxy might end up not sending any final response to UAC, because "best response selection" happens only when all the client transaction in RC got the final response. Hence I feel Timer C is pretty much necessary for the state full proxy functionality. > > Thanks and Regards, > Geetha. > -- > karthik > [EMAIL PROTECTED] > > -- > http://www.fastmail.fm - Or how I learned to stop worrying and > love email again > > _______________________________________________ > Sip-implementors mailing list > [email protected] > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
