Re: [Sip] Questions about the SIP Replaces Header draft.

Henry Chen <hjlechen@cisco.com> Thu, 06 September 2001 20:53 UTC

Received: from optimus.ietf.org (ietf.org [132.151.1.19] (may be forged)) by ietf.org (8.9.1a/8.9.1a) with ESMTP id QAA08815 for <sip-archive@odin.ietf.org>; Thu, 6 Sep 2001 16:53:43 -0400 (EDT)
Received: from optimus.ietf.org (localhost [127.0.0.1]) by optimus.ietf.org (8.9.1a/8.9.1) with ESMTP id QAA04427; Thu, 6 Sep 2001 16:40:15 -0400 (EDT)
Received: from ietf.org (odin [132.151.1.176]) by optimus.ietf.org (8.9.1a/8.9.1) with ESMTP id QAA04379 for <sip@ns.ietf.org>; Thu, 6 Sep 2001 16:40:12 -0400 (EDT)
Received: from sj-msg-core-2.cisco.com (sj-msg-core-2.cisco.com [171.69.24.11]) by ietf.org (8.9.1a/8.9.1a) with ESMTP id QAA08239 for <sip@ietf.org>; Thu, 6 Sep 2001 16:38:44 -0400 (EDT)
Received: from driftwood.cisco.com (driftwood.cisco.com [171.71.157.40]) by sj-msg-core-2.cisco.com (8.11.3/8.9.1) with ESMTP id f86Kdwv09540; Thu, 6 Sep 2001 13:39:58 -0700 (PDT)
Received: from cisco.com (dhcp-171-71-159-231.cisco.com [171.71.159.231]) by driftwood.cisco.com (Mirapoint) with ESMTP id AHU03930; Thu, 6 Sep 2001 15:39:23 -0500 (CDT)
Message-ID: <3B97DF17.9449204F@cisco.com>
Date: Thu, 06 Sep 2001 15:39:51 -0500
From: Henry Chen <hjlechen@cisco.com>
X-Mailer: Mozilla 4.73 [en]C-CCK-MCD (Windows NT 5.0; U)
X-Accept-Language: en
MIME-Version: 1.0
To: "Padhye, Chinmay" <c_padhye@trillium.com>
CC: "'sip@ietf.org'" <sip@ietf.org>
Subject: Re: [Sip] Questions about the SIP Replaces Header draft.
References: <F1CE15E08172D4119247009027AE9D500E4EB21E@FMSMSX37>
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Content-Transfer-Encoding: 7bit
Sender: sip-admin@ietf.org
Errors-To: sip-admin@ietf.org
X-Mailman-Version: 1.0
Precedence: bulk
List-Id: Session Initiation Protocol <sip.ietf.org>
X-BeenThere: sip@ietf.org
Content-Transfer-Encoding: 7bit

More questions in line.

Henry

"Padhye, Chinmay" wrote:

> Hello,
>
>         I have a few questions and comments regarding the SIP Replaces
> Header draft -
> http://www.softarmor.com/sipwg/drafts/draft-biggs-sip-replaces-01.txt.
>
> 1)      In section 3 the draft states -
>         "The to-tag and from-tag parameters MUST be included in the Replaces
> header, as they are required for unique call-leg matching."
>
>         In section 4 the draft states -
>         "If the Replaces header matches more than one call-leg, the user
> agent MAY use the Referred-By header if present to attempt to match the call
> with an appropriate call-leg, but should otherwise ignore the header."
>
>         The REFER draft says that the Referred-By header is mandatory
> (section 3.2 of REFER 01 draft). Hence the words "if present" in the above
> statement must be removed.
>
>         I also have a question regarding this -
>
>         a)      When will a Replaces header match more than one call-leg.
> The statements in the section 3 and 4 seem to contradict each other.
>
> 2)      In section 4 of the draft it says -
>
>         "If the Replaces header matches an unestablished call leg, that it,
> the INVITE request for the call has not received or been sent a final
> response, the Replaces header MUST be ignored."
>
>         The "it" is a typo and should be "is".
>
>         My question is -
>         How will a Replaces header match an unestablished call leg when a
> response has not been received for an INVITE?

Can the SIP user agent cancel the unestablished call leg instead of ignoring the
Replaces header?
What is the reason behind to ignore Replaces header for an unestablished
matching call leg?

>
>
> 3)      I think the figures shown with the examples do not conform to the
> latest REFER draft. None of the figures show NOTIFY being used.
>
> 4)      The reference to the cc draft - reference [4], is to the old draft.
>
> Regards,
>
> Chinmay
>
> _______________________________________________
> Sip mailing list  http://www1.ietf.org/mailman/listinfo/sip
> This list is for NEW development of the core SIP Protocol
> Use sip-implementors@cs.columbia.edu for questions on current sip
> Use sipping@ietf.org for new developments on the application of sip


_______________________________________________
Sip mailing list  http://www1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use sip-implementors@cs.columbia.edu for questions on current sip
Use sipping@ietf.org for new developments on the application of sip