Subject: RE: [SIP] Question on "base" in draft-ietf-sip-isup-mime-07.txt

From: [email-masked]
Date: Wed, 31 Jan 2001 23:06:21 -0700

I think it was the hope of the authors that all of the meaningful values for
'base' would be characterized in the document. Since 'base' reflects the
lowest common dominator (or, to coin a phrase, least specific ancestor)
variant of the ISUP version in question, the authors hoped that given the
backwards compatibility mechanism in ITU-T 1992 Q.76x, itu92 would be the
proper base for forthcoming ISUP versions (new versions of ANSI following
the 2000 issue support this mechanism, even).

That much said, if there are potential 'base' values which are of use to the
community that cannot be said to derive from itu92, the authors would
certainly like to be made aware of them. Is there anything out there that
the ISUP MIME draft misses?

In the face of serious concerns that useful new 'bases' might come to light
subsequent to the publication of an RFC, I suppose management of 'base' by
IANA could be introduced, but personally I'd rather not trouble IANA with
this additional responsibility if there isn't a substantial risk. Was there
anything specific you had in mind?

Jon Peterson
Level(3) Communications

-----Original Message-----
From: Chip Sharp [mailto:[email-masked]]
Sent: Tuesday, January 30, 2001 10:50 AM
To: [email-masked]
Subject: [SIP] Question on "base" in draft-ietf-sip-isup-mime-07.txt

Currently, the IANA considerations section of 
draft-ietf-sip-isup-mime-07.txt describes how to define new "version" 
fields, but does not describe how to define new "base" fields.

Given that new base protocols may be identified, shouldn't there be a 
description on how IANA assigns new "base" values?

Chip

-------------------------------------------------------------------
Chip Sharp                       Consulting Engineering
Cisco Systems
-------------------------------------------------------------------

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---

From: "Lebovits, Doris S, ALCOO" <[email-masked]>
Date: Thu, 1 Feb 2001 10:11:20 -0500

Jon,
I do not agree with your comments. I think ITU-T ISUP 2000 should be the
base,
as it is the base going forward. ITU-T ISUP 2000 is backwards compatible
with
previous versions such as ISUP '92. The options in ITU-T ISUP 2000 that
would
not need to be specified for this activity could be highlighted as not
mandatory.
The ANSI version of ISUP is T1.113 and has been updated to the ITU-T ISUP
2000 
level and is in the final stages for publication. 

Doris Lebovits
AT&T
[email-masked]
==========================================================

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Thursday, February 01, 2001 1:06 AM
To: [email-masked]; [email-masked]
Subject: RE: [SIP] Question on "base" in draft-ietf-sip-isup-mime-07.txt

Jon Peterson
Level(3) Communications

-----Original Message-----
From: Chip Sharp [mailto:[email-masked]]
Sent: Tuesday, January 30, 2001 10:50 AM
To: [email-masked]
Subject: [SIP] Question on "base" in draft-ietf-sip-isup-mime-07.txt

Chip

---

From: "Roy, Radhika R, ALCOO" <[email-masked]>
Date: Thu, 1 Feb 2001 11:38:44 -0500

Hi, Jon:

In addition, I have one more (indirect) question.

Your draft also refers to the ISUP to SIP Mapping I-D
(draft-ietf-sip-isup-00.txt). The call flows of this draft may also need to
be revisited with respect the call flows provided in the I-D
draft-ietf-sip-call-flows-02. It might be different issues, but may be
relevant later because a lot of unresolved issues mentioned in you draft may
also be addressed in the future.

Best regards,
Radhika R. Roy
AT&T

-----Original Message-----
From: Lebovits, Doris S, ALCOO 
Sent: Thursday, February 01, 2001 10:11 AM
To: [email-masked]'
Cc: [email-masked]; [email-masked]
Subject: RE: [SIP] Question on "base" in draft-ietf-sip-isup-mime-07.txt

Jon,

Doris Lebovits
AT&T
[email-masked]

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Thursday, February 01, 2001 1:06 AM
To: [email-masked]; [email-masked]
Subject: RE: [SIP] Question on "base" in draft-ietf-sip-isup-mime-07.txt

Jon Peterson
Level(3) Communications

-----Original Message-----
From: Chip Sharp [mailto:[email-masked]]
Sent: Tuesday, January 30, 2001 10:50 AM
To: [email-masked]
Subject: [SIP] Question on "base" in draft-ietf-sip-isup-mime-07.txt

Chip

---

From: "Mark Watson" <[email-masked]>
Date: Thu, 1 Feb 2001 18:38:56 -0000

It doesn't really matter which version of ITU-T ISUP we reference - because
after 1992 they are all backwards compatible with each other.

The point was that there only needs to be a single 'base' value for
post-1992 ITU-T ISUPs. As soon as the ISUP processor sees this, it knows
that it can handle unrecognised information according to the compatibility
procedure and so can sucessfully process the message.

Given this, ISUP 1992 was chosen because it was the first version with the
compatibility mechanism. It would be arbitrary to choose another version -
why not 1997 or 2004 ??

The intent of this 'base' value is to imply that the encapsulated signalling
is based on an ITU-T ISUP version 1992 or later, so it covers ISUP 2000.

Regards,

Mark Watson

> From: Lebovits, Doris S, ALCOO [mailto:[email-masked]]
> Sent: 01 February 2001 15:11
> Cc: ; [email-masked]

---

From: "Lebovits, Doris S, ALCOO" <[email-masked]>
Date: Thu, 1 Feb 2001 14:40:07 -0500

Mark,
My concern is the ability to handle the new ISUP messages and parameters.
Insure that these do not end up as unrecognized
messages and parameters. Also there is a need for the new application
transport message (APM) and new application
transport parameter (APP) supporting APM. It is not arbitrary to select
ITU-T ISUP 2000 as it is the last significant version.Having the 'base'
value to encapsulated signalling based on ITU-T ISUP 2000, also covers ISUP
92, from a compatibility point of view.
 
Doris Lebovits
[email-masked]
----------------------------------------------------------------------------
---------------------
 
 -----Original Message-----
From: Mark Watson [mailto:[email-masked]]
Sent: Thursday, February 01, 2001 1:39 PM
To: [email-masked]'; Lebovits, Doris S, ALCOO
Subject: RE: [SIP] Question on "base" in draft-ietf-sip-isup-mime-07.txt

Regards, 

Mark Watson 

> From: Lebovits, Doris S, ALCOO [ mailto:[email-masked]
<mailto:[email-masked]> ] 
> From: [email-masked] [ mailto:[email-masked]
<mailto:[email-masked]> ] 
> From: Chip Sharp [ mailto:[email-masked] <mailto:[email-masked]> ]

---

From: [email-masked]
Date: Thu, 1 Feb 2001 15:27:27 -0700

This could be accomodated by having ISUP 2000 registered as a -version- with
IANA, but using itu92 as a -base-. This has come up a couple of times now.
Clearly, the most compatible ISUP variant characterization should appear in
the base string, and version characterizations that identify additional
features/options above and beyond the base should be identified in the
version string. Entities that recognize the version will preserve all of the
features present in ISUP 2000. I don't see why that can't work for your
case. Is the version/base distinction in the draft unclear on these sorts of
points?

Also please do note that WG last call for this document ended some weeks ago
now.

Jon Peterson
Level(3) Communications

-----Original Message-----
From: Lebovits, Doris S, ALCOO [mailto:[email-masked]]
Sent: Thursday, February 01, 2001 12:40 PM
To: 'Mark Watson'
Cc: [email-masked]'
Subject: RE: [SIP] Question on "base" in draft-ietf-sip-isup-mime-07.txt

Mark,
 
Doris Lebovits
[email-masked]
 
 -----Original Message-----
From: Mark Watson [mailto:[email-masked]]
Sent: Thursday, February 01, 2001 1:39 PM
To: [email-masked]'; Lebovits, Doris S, ALCOO
Subject: RE: [SIP] Question on "base" in draft-ietf-sip-isup-mime-07.txt

Regards, 

Mark Watson