Also, I strongly suggest you don't put 100rel in Require unless you and your customers/users actually want the call to fail if the other end doesn't support it. Lots of devices don't support PRACKs - probably more don't than do. Putting it in Supported often does make the far end use it if it supports it, without failing the call if it doesn't. I only mention this because some developers are putting it in Require when they don't really mean that semantic, and then their customers make middle-boxes fix the mismatch for them which is an ugly model.
-hadriel > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:sip- > [EMAIL PROTECTED] On Behalf Of Paul Kyzivat > Sent: Thursday, March 27, 2008 2:19 PM > To: Sourav Dhar Chaudhuri > Cc: sip-implementors@lists.cs.columbia.edu > Subject: Re: [Sip-implementors] For sending PRACK for a RPR is it > mandatory to have Supported:100rel in INVITE while it already contains > Require:100rel in INVITE > > > > Sourav Dhar Chaudhuri wrote: > > Thanks for your reply but I think you don't get my point. > > > > 1. Here Caller A does not have Supported:100rel but in the INVITE > > request contains Require:100rel. So now suppose callee B send a RPR > > whether Caller A will able to generate PRACK because Caller A does not > > have Supported:100rel > > You are allowed to exercise features even if you don't know if the other > side supports them. So B may send the reliable provisional, and > presumably should, since otherwise the call must fail. He was asked to > do so, so go ahead and do it. It is *possible* that A would return a 420 > error in this case, but not likely. > > > 2. One more scenario Caller A send a INVITE request with both > > Supported:100rel & Require:100rel to callee B. > > (In Callee B contains Require:100rel but no Supported:100rel. means if > > any time callee B makes another INVITE to a new Callee C that INVITE > > request will contain Require:100rel but no Supported:100rel.) > > So now callee B will send RPR or not as it has the feature > > Require:100rel but no Supported:100rel? > > I can't quite parse the intent of the sentence above. If A sent both, > the B knows it can (and must) use reliable provisionals. > > The only remaining interesting question I see then is what should happen > if B sends a reinvite to A in the dialog. In that case B may include a > Require or not, and a Supported or not. If there is Supported but no > Require in that case, A may send reliable provisionals or not. Not > sending them in this case is a bit odd. I'd find it surprising if > anybody does that. > > Paul > > > ----- Original Message ---- > > From: Paul Kyzivat <[EMAIL PROTECTED]> > > To: Sourav Dhar Chaudhuri <[EMAIL PROTECTED]> > > Cc: sip-implementors@lists.cs.columbia.edu > > Sent: Thursday, 27 March, 2008 8:52:12 PM > > Subject: Re: [Sip-implementors] For sending PRACK for a RPR is it > > mandatory to have Supported:100rel in INVITE while it already contains > > Require:100rel in INVITE > > > > Note that Supported talks about what the *sender* of the message > > containing it supports. Require talks about what the *recipient* of the > > message containing it (must) support. > > > > For some options its possible that only one side need support the > > option. For others that makes no sense. (One where it does make sense is > > "timer".) > > > > As a result, there is no implied linkage between the two. Put in > > Supported if *you* support it, and put in Require if you require that > > the *other guy* support it. > > > > Paul > > > > Sourav Dhar Chaudhuri wrote: > > > Hi, > > > I have a doubt is it mandatory to haveSupported:100rel in > > INVITE request while it already contains Require:100rel inINVITE. > > > > > > 2. One more question is it possible that a Caller cannot sendPRACK > > for a Reliable Provisional Response(RPR) as it contains > > Require:100relbut no Supported:100rel in its INVITE request. > > > > > > I am asking the second question because if that thesame > > capability is present in Callee so whether after receiving any > > INVITEwith Require:100rel , whether callee will be not be able to send > RPR. > > > > > > Thanks > > > SOURAV DHAR CHAUDHURI > > > > > > > > > > > > > > > > > > > > > > > > Did you know? You can CHAT without downloading messenger. Go to > > http://in.messenger.yahoo.com/webmessengerpromo.php/ > > > _______________________________________________ > > > Sip-implementors mailing list > > > Sip-implementors@lists.cs.columbia.edu > > <mailto:Sip-implementors@lists.cs.columbia.edu> > > > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > > > > > > > > > ------------------------------------------------------------------------ > > Chat on a cool, new interface. No download required. Click here. > > > <http://in.rd.yahoo.com/tagline_webmessenger_10/*http://in.messenger.yahoo > .com/webmessengerpromo.php> > _______________________________________________ > Sip-implementors mailing list > Sip-implementors@lists.cs.columbia.edu > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
