RE: Example of LOM usage

["Ash, Gerald R (Jerry), ALABS" <gash@att.com>]

Francois,

> Documenting LOM as Experimental is an attempt at a compromised approach
> to try move ahead considering this disagreement. It would allow folks
> who see it as something worthwhile to have it documented so it can be
> experimented with, and even easily added to standards track in some
> future if backed by experience. It would allow folks who question the
> practical use of LOM to see a leaner DS-TE solution (at least to start
> with). 
> 
> Assuming we can close-off the potential questions you may have
> surrounding the idea of splitting LOM in a separate document, could you
> live with this compromised approach of an Experimental track for LOM?

In the interest of moving ahead, I'm OK with the compromise to split off LOM from the Proto and BC drafts, and progress it separately on an Experimental track.  

However, I do not agree that the starting point for the separate effort on LOM should be the current proposal.  While I believe the concept of having a separate per-link, per-CT adjustment for overbooking, such as proposed with LOM, is worth pursuing, I also believe that the particular implementation proposed in Proto is problematic, and needs a re-work.  In particular, 

1. It's not at all clear what 'normalized CTc' really means: it's not reserved BW, it's not overbooked bandwidth, what is it?  It's not a physical quantity, which makes it abstract and confusing.

2. The router reserves Tspec(LSPc) (i.e., reserved(LSPc)=Tspec(LSPc), what does it do with normalized CTc?

3. It's not at all clear what SUM [normalized_CTc] should be constrained by.  Neither Maximum Reservable Bandwidth (MRBW) nor Maximum Link Bandwidth seem correct.

4. It's not at all clear how to set BCc in terms of normalized_CTc, how should that be done, and how do the BCs relate to MRBW?

If you can shed any light on these issues 1 --> 4, with some specific numerical examples, please do.

It is much easier to understand physical quantities like reserved_CTc, what they should sum to (MRBW), how they related to BCs, etc.

I think the concepts proposed in the post on June 1 http://ops.ietf.org/lists/te-wg/te-wg.2003/msg00321.html have merit, and should be considered in the re-initiated effort on LOM.  Wai Sum and I have expanded this proposal in an I-D that we will soon submit for discussion.  The proposed approach is coherent, I believe, while the current approach is not.  I think the I-D with our proposal for LOM should be considered in this effort.

Thanks,
Jerry