Subject: Diverse inter-region path setup

From: "Alessio D'Achille" <[email-masked]>
Date: Mon, 2 Aug 2004 23:11:35 +0200

Dear all,
 
with this mail we would like to focus the attention on the disjoint path
computation issue, within the context of inter-area/AS TE.
 
We believe that not addressing the disjoint path computation issue from
the start (when looking at inter-area/AS TE) would be quite problematic,
since an approach that works for a single inter-area/AS path may not be
easily applicable/extendible for diverse path 
computation. This observation has been made earlier on ML discussions
after the Seoul meeting, but there was no definitive conclusion at that
time ( <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00336.html>
http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00336.html
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00336.html> and
follows). In fact, in our view, the right way to approach this issue
would be to develop an approach that that does not provide a solution to
setup a single path and then attempts to extend that solution for the
diverse path setup case.Rather, a solution
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00336.html> must provide
a mechanism to setup disjoint paths, with the single path setup being a
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00336.html> particular
case. This is because disjoint path setup is quite likely one of the
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00336.html> more
important aspects of inter-region TE, that is important for a no. of
applications,
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00336.html> as pointed
out in the requirements drafts.
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00336.html>  
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00336.html> We defined
such an approach in our draft
"draft-dachille-inter-area-path-protection-
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00336.html> 00.txt",
discussed in Seoul (59th IETF) and it received many positive comments
(see the
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00336.html> minute of
the meeting): in many comments it has been marked as an important work,
since it addressed a hot issue within the Inter-area/AS topic.
Following, the draft has been discussed on the CCAMP ML for about two
months Recently we have reviewed our draft (namely
draft-dachille-diverse-inter- region-path-setup-00), incorporating the
feedbacks received at Seoul and via the CCAMP discussions that followed.
Since there are significative changes, we recently asked for a slot
during the 60th IETF, just to discuss the new version
(http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00720.html).
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00720.html>  
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00720.html> We would
like to address two main themes:
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00720.html>  
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00720.html> i) clarifing
why an approach to achieve diverse path setup from the 
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00720.html> start is now
not considered in the inter-region TE solutions, 
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00720.html>
notwithstanding it seems to be the right approach to the issue, as 
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00720.html> observed in
prior ML discussion and in requirement drafts.
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00720.html>  
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00720.html> ii) Since we
believe that draft-dachille satisfies all the 
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00720.html> requirements
for work to be discussed at a WG meeting 
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00720.html>
(http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00746.html),
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00746.html> we would
appreciate clarification about the reasons that led to the 
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00746.html> exclusion of
this work from the SD agenda.
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00746.html>  
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00746.html> Thank you
for your kind attention; we hope that the discussion about 
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00746.html> this issue
could continue in a productive manner, just as usual.
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00746.html>  
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00746.html> Best
Regards,
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00746.html>  
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00746.html> Alessio
D'Achille
 <http://ops.ietf.org/lists/ccamp/ccamp.2004/msg00746.html>

---

From: "Adrian Farrel" <[email-masked]>
Date: Tue, 3 Aug 2004 01:58:39 +0100

Hi,

Kireeti plans to spend ten minutes discussing the strategy for inter-domain TE work within
CCAMP. This is on the agenda at:
- Inter-Area/AS
   - Strategy (Kireeti) (10 minutes)

We hope that he will answer your questions at that time and outline the way forward.
Of course, we will welcome a brief discussion of the right way to proceed at that time.

Thanks,
Adrian

----- Original Message ----- 
From: "Alessio D'Achille" <[email-masked]>
To: <[email-masked]>
Cc: <[email-masked]>; "Kireeti Kompella" <[email-masked]>; "Vishal Sharma"
<[email-masked]>; "Ugo Monaco" <[email-masked]>; "Fabio Ricciato"
<[email-masked]>; "Marco Listanti" <[email-masked]>
Sent: Monday, August 02, 2004 10:11 PM
Subject: Diverse inter-region path setup