On Thu, 2002-07-18 at 13:34, Ranjit Avasarala wrote:
> u cannot send CANCEL for re-invite as u won't be getting any ringing tone as
> response
This is not correct.
If you have received a provisional response, you can, in fact, send
a CANCEL to a re-INVITE. However, the nature of re-INVITE is such
that it is not likely to pend for long, so the chances that the CANCEL
won't arrive in time to affect the re-INVITE are higher than they are
for an initial INVITE.
>
> Ranjit
> ----- Original Message -----
> From: Suresh Arora <[EMAIL PROTECTED]>
> To: Medhavi Bhatia <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
> Sent: Wednesday, July 17, 2002 6:14 PM
> Subject: RE: [Sip] CANCEL FAQs
>
>
> > I think UAS can send CANCEL to UAC for a re-INVITE (if requested session
> > characteristics are not supported by Server).
As Ajit already pointed out, if the UAS doesn't like an INVITE request
it sends a response, not another request. CANCEL works like this:
INVITE
-------->
CANCEL
-------->
NOT like this:
INVITE
-------->
CANCEL
<--------
For the case you call out (unsupported session characteristics) the
UAS will return a 488 (or possibly a 606). Thus:
INVITE
-------->
488
<--------
> >
> > -Suresh
> >
> > -----Original Message-----
> > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Medhavi
> > Bhatia
> > Sent: Wednesday, July 17, 2002 9:21 AM
> > To: [EMAIL PROTECTED]
> > Subject: Re: [Sip] CANCEL FAQs
> >
> >
> > This stuff generally belongs to the implementor's list: sip-implementors
> > <[EMAIL PROTECTED]>
> >
> > Generally CANCEL should not be used for transactions which are bound to
> > complete
> > quickly, and never for transactions for which you havent received a
> > provisional (1xx)
> > response. So the answer for (1) would be: probably not. Also the UAS
> cannot
> > cancel
> > a transaction started by the UAC (I guess that's what you meant), so it
> > cannot generate
> > the CANCEL ever.
> >
> > ----- Original Message -----
> > From: "Sp.Raja" <[EMAIL PROTECTED]>
> > To: <[EMAIL PROTECTED]>
> > Sent: Tuesday, July 16, 2002 6:25 AM
> > Subject: [Sip] CANCEL FAQs
> >
> >
> > > Please help me out by answering these questions.
> > >
> > > 1. Can CANCEL be used to cancel a bye ?
> > >
> > > 2. Can CANCEL be send by the called entity (UAS) ? If yes then under
> what
> > > circumstances
The answers above probably address what you meant, but to be
complete:
The "called entity" plays the role of a UAS for the transaction
processing the INVITE it received. It cannot CANCEL that transaction,
it can only send responses in it.
If that INVITE is accepted, the called entity can later send
its own requests (such as (re-)INVITE). It is playing the roal
of a UAC for those request transactions, and once it recieves
a provisional response, it can send CANCELs.
RjS
> > >
> > > - Sp.Raja
> > >
> >
> >
> > _______________________________________________
> > Sip mailing list https://www1.ietf.org/mailman/listinfo/sip
> > This list is for NEW development of the core SIP Protocol
> > Use [EMAIL PROTECTED] for questions on current sip
> > Use [EMAIL PROTECTED] for new developments on the application of sip
> >
> >
> >
> > _______________________________________________
> > Sip mailing list https://www1.ietf.org/mailman/listinfo/sip
> > This list is for NEW development of the core SIP Protocol
> > Use [EMAIL PROTECTED] for questions on current sip
> > Use [EMAIL PROTECTED] for new developments on the application of sip
>
>
> _______________________________________________
> Sip mailing list https://www1.ietf.org/mailman/listinfo/sip
> This list is for NEW development of the core SIP Protocol
> Use [EMAIL PROTECTED] for questions on current sip
> Use [EMAIL PROTECTED] for new developments on the application of sip
_______________________________________________
Sip-implementors mailing list
[EMAIL PROTECTED]
http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
