Subject: RE: [Sip] INFO considered harmful

From: "Mark Watson" <[email-masked]>
Date: Tue, 7 Jan 2003 10:04:58 -0000

Frank,
 
I guess my concern is that there is an important difference between
transparently carrying ISUP information between 'ISUP capable' devices
(which we have a way to do with SIP-T), and defining new formats for
'ISUP-style' information to be processed by non-ISUP-capable nodes in the
SIP network. This second just sounds like defining extensions to SIP.
 
There's been lots of discussion about processes for defining extensions to
SIP - both standard and 'proprietary/preliminary ...'. Don't want to repeat
these here, but usually there is some opposition to just importing things
from ISUP.
 
Was your intention that this approach be published as Informational, or
rolled in to the GTD work in ITU ?
 
...Mark

-----Original Message-----
From: Frank W. Miller [mailto:[email-masked]]
Sent: 06 January 2003 18:37
To: Watson, Mark [MOP:EP10:EXCH]
Cc: [email-masked]
Subject: Re: [Sip] INFO considered harmful

We just arbitarily picked:
 
Content-type: applicaton/isupxml
 
That is in the -01 version of this document that I referred to earlier.
Sorry, I'll get it up on the IETF site as quick as I can, hopefully within
the week.
 
It is explictly outside the scope of the group, by choice I believe.  But
this and the TCAP stuff are good examples of what I've been advocating, the
need for some mechanism to allow stuff thats "related" but not necessarily
appropriate (and in this case explictly shunned) for the mainline standard.
We actually looked at using SOAP for this (as was suggested by Adam) and
decided against it for simple expedience (read development cost) reasons.
The mechanism present in our (third-party) SIP implementation was so
compelling coupled with an off the shelf XML parser, that it didnt make
sense to do anything else...
 
Furthermore, I would argue that you really never want anything like this to
be included in the mainline standard for a couple of reasons.  First, it is
very application specific.  Second, hopefully as SIP gains momentum and SS7
loses momentum with the large carriers, this stuff will just fade away...
 
FM
 
Frank W. Miller
Chief Technical Officer
sentitO Networks, Inc.
[email-masked]

----- Original Message ----- 
From: Mark Watson <mailto:[email-masked]>  
To: 'Frank W.  <mailto:[email-masked]> Miller' ; Dean Willis
<mailto:[email-masked]>  
Cc: [email-masked] <mailto:[email-masked]>  
Sent: Monday, January 06, 2003 1:07 PM
Subject: RE: [Sip] INFO considered harmful

Looks at first glance like the Generic Transparency Descriptor which has
been proposed within ITU-T Study Group 11 and ANSI T1S1. Just out of
interest, what would be the MIME type for carrying this in SIP ?

Is recoding of ISUP into text format exactly in the scope of the IETF SIP
group ?

---

From: "Frank W. Miller" <[email-masked]>
Date: Tue, 7 Jan 2003 10:04:17 -0500

RE: [Sip] INFO considered harmful
The main issue with SIP-T is that it requires some portion of the SS7 stack to be present in the IP elements of the network.  I see SIP-T as being primarily useful as an IP network transport of ISUP between SS7 "islands".  If an SS7 element wants to control say a T-1 that happens to be SIP terminated, I feel that a translation is a better approach.  It limits the need to deploy (very expensive from a dollar and point code point of view) ISUP protocol elements.  Also, if done right, it can eliminate the country variant problem that is IMHO a huge problem for SS7.

As far as my intentions with these drafts, I have none, other than a desire for this protocol information to be in the public domain.  I've heard rumblings about addressing SIP interaction in the ITU and also Telcordia.  I have not participated in the ITU forums actively to date.  If IETF takes it up, thats fine.  If there's synergy with ITU, thats fine too.  I like IETF because there's a mechanism for making things public without having to really go though all the pain of committees.  It doesnt mean its sanctioned by IETF but the openness of the forum is more appealing to me than some of the other standards groups I've been involved with over time.

FM

  ----- Original Message ----- 
  From: Mark Watson 
  To: 'Frank W. Miller' 
  Cc: [email-masked] 
  Sent: Tuesday, January 07, 2003 5:04 AM
  Subject: RE: [Sip] INFO considered harmful

  Frank,

  I guess my concern is that there is an important difference between transparently carrying ISUP information between 'ISUP capable' devices (which we have a way to do with SIP-T), and defining new formats for 'ISUP-style' information to be processed by non-ISUP-capable nodes in the SIP network. This second just sounds like defining extensions to SIP.

  There's been lots of discussion about processes for defining extensions to SIP - both standard and 'proprietary/preliminary ...'. Don't want to repeat these here, but usually there is some opposition to just importing things from ISUP.

  Was your intention that this approach be published as Informational, or rolled in to the GTD work in ITU ?