I don't see any discrepancy. BYE is used to terminate a single dialog
whether it be an early dialog or a confirmed dialog. CANCEL is used to
terminate a pending INVITE and every thing associated with the pending
INVITE including all dialogs and forked branches. The thing that people
forget is that an INVITE can create multiple dialogs.

If a UAC has sent an INVITE and it wishes to terminate the session after
receiving one or more provisional responses, it sends CANCEL.

A BYE would only be used in the exceptional case where the UAC received
provisional responses from multiple UASs, thus establishing multiple early
dialogs, and the UAC want to keep one (let it complete), and terminate
others (with a BYE).

Again, the CANCEL is canceling the INVITE, not terminating a dialog. All
early dialogs associated with the INVITE are terminated as a side effect of
the INVITE termination.

cheers,
(-:bob

Robert F. Penfield
Chief Software Architect
Acme Packet, Inc.
130 New Boston Street
Woburn, MA 01801
[EMAIL PROTECTED]

----- Original Message ----- 
From: "Ramachandran Iyer" <[EMAIL PROTECTED]>
To: "Bob Penfield" <[EMAIL PROTECTED]>; "Karthik M"
<[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Tuesday, April 27, 2004 2:52 AM
Subject: Re: [Sip-implementors] Early session and Cancel


> Hey Bob,
>   I think what you said below is in line with what the spec recommends of
how to terminate a early dialog by using BYE...
>   But i am a bit amused becasue we have always been talking from the
2543-biz days that we would always have to use a CANCEL for terminating
session (in this case the session being a 'early dialogue' formation.. by
say a 180.. The idea being that all sessions which have not received a final
response 2xx-6xx will have to be terminated by sending out a CANCEL and not
a BYE. A BYE for terminating to be used only on receipt of a final
response.. (obviously after having ACK'd the final response)...
>
>    So is'nt there a bit of discrepancy in the way we use our CANCEL and
BYE? atleast in the way of how we are terminating early dialogue's..
>
> Rama
>
>
> Bob Penfield <[EMAIL PROTECTED]> wrote:
> The use of BYE is only required if the UAC wants to terminate a particular
> early dialog, but let other early dialogs or pending branches of the
INVITE
> continue. CANCEL is used if the UAC wants to cancel the whole INVITE
> including all early dialogs and all outstanding forked branches of the
> INVITE.
>
> cheers,
> (-:bob
>
> Robert F. Penfield
> Chief Software Architect
> Acme Packet, Inc.
> 130 New Boston Street
> Woburn, MA 01801
> [EMAIL PROTECTED]
>
> ----- Original Message ----- 
> From: "Karthik M"
> To:
> Sent: Monday, April 26, 2004 10:37 AM
> Subject: [Sip-implementors] Early session and Cancel
>
>
> > Hello all,
> > In a dialog, if an early session is established through 180 and if the
> UAC wants to cancel the invite transaction, Should the cancel be discarded
> and the entire dialog should be released only by BYE. I tried to
understand
> the "Terminating the session" part in the RFC 3261. but still its not
clear
> to me.
> >
> > Also i found in one posting of this mailing list that BYE should be
> sent to terminate that session that is established and if the cancel is
> sent, then all the forking requests and the early session are also
> terminated. Is that correct?
> >
> > Please clarify me.
> >
> > TIA
> > Karthik M
> >
>
>
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