Subject: [Sip] Relationship between Dialog and Call-ID

From: "Patrick Lam" <[email-masked]>
Date: Wed, 9 Apr 2003 16:00:59 +0800

Dear all:

I am a little confused about the relationship between a dialog and the
Call-ID:

1.	Do requests "within the same dialog" use identical Call-ID, while
requests "outside of a dialog" use different Call-ID than those "within"?
2.	In the last paragraph on p.16 in RFC 3261:

"This re-INVITE references the existing dialog so that the other party knows
that it is to modify an existing session instead of establishing a new
session."

What does the re-INVITE use to refer to the existing dialog?  Call-ID?

Thanks very much in advance.

Regards,

Patrick

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From: [email-masked]
Date: Wed, 9 Apr 2003 14:37:41 +0530

Hello Patrick,

1. Yes. Message within same dialog use same Call-ID

In case of re-INVITE same Call-ID facilitates in relating  re-INVITE to the
existing session.
The (to, from, Call-ID) are maintaind same as that in original INVITE.

Rayees

"Patrick Lam" <[email-masked]>@ietf.org on 04/09/2003 01:30:59 PM

Sent by:    [email-masked]

To:    <[email-masked]>
cc:

Subject:    [Sip] Relationship between Dialog and Call-ID

Dear all:

"This re-INVITE references the existing dialog so that the other party
knows
that it is to modify an existing session instead of establishing a new
session."

Regards,

 Patrick
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Policy.

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---

From: "Patrick Lam" <[email-masked]>
Date: Wed, 9 Apr 2003 17:27:14 +0800

Phil:

Thanks for your answer.  Just a little more to clarify: when I send an
re-INVITE for a particular dialog, I have to use the same Call-ID, To/From
tag for that particular dialog?  Would the re-INVITE be forked as well?  If
so, what would I do with the re-INVITE?

Thanks again.

Patrick

-----Original Message-----
From: Phil Reynolds [mailto:[email-masked]] 
Sent: Wednesday, April 09, 2003 4:52 PM
To: Patrick Lam
Subject: RE: [Sip] Relationship between Dialog and Call-ID

A dialog is identified by the Call-ID, to-tag and from-tag. The Call-ID
itself is insufficient as the same INVITE may have been forked to several
different recipients that may all create dialogs.

	 -----Original Message-----
	From: 	[email-masked] [mailto:[email-masked]]  On Behalf Of
Patrick Lam
	Sent:	09 April 2003 09:01
	To:	[email-masked]
	Subject:	[Sip] Relationship between Dialog and Call-ID

	Dear all:

	I am a little confused about the relationship between a dialog and
the Call-ID:

	1.	Do requests "within the same dialog" use identical Call-ID,
while requests "outside of a dialog" use different Call-ID than those
"within"?
	2.	In the last paragraph on p.16 in RFC 3261:

	"This re-INVITE references the existing dialog so that the other
party knows that it is to modify an existing session instead of establishing
a new session."

	What does the re-INVITE use to refer to the existing dialog?
Call-ID?

	Regards,

	Patrick