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: [email protected]
> 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
> >
> >
> >
> >
> >
> >
> >
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