Subject: draft-ashwood-ccacmp-gmpls-constraints

From: "Don Fedyk" <[email-masked]>
Date: Wed, 3 Aug 2005 12:50:37 -0400

Hi 

Since we did not get through all the CCAMP agenda today, I would still
like to get feedback on the following draft. 

Link Viability Constraints Don Fedyk (5 mins) 
http://home.clara.net/olddog/63/draft-ashwood-ccamp-gmpls-constraint-req
ts-00.ppt
http://www.ietf.org/internet-drafts/draft-ashwood-ccamp-gmpls-constraint
-reqts-00.txt

Note the draft is about interfacing a dynamic optical system to a GMPLS
control plane but puts forward the argument we can avoid for now the
standardization of the detailed optical constraints.  I would like to
see this in Scope for the IETF (CCAMP) even though I realize the
detailed (or complex) optical constraints may be years from being in
scope and standardization. The current draft is a requirements draft
with some preliminary ideas on how this can be achieved. I would like to
solicit others who are interested in working this problem.

Please send feedback, I'm around till Friday if anyone would like to
discuss in person,
Thanks,
Don

---

From: [email-masked]
Date: Thu, 4 Aug 2005 05:32:07 -0400 (EDT)

Hi,

I believe this is a very useful draft. The described blocking problem (a
limited ability of a node to cross-connect resources on input and output
links wrt a particular LSP) exists not only in the Virtual Node scenario:
there could be “real” network elements experiencing the problem (perhaps,
because of the hardware limitations). Hence there is a need for a routing
controller to be capable to advertise a map of acceptable (or
unacceptable) input-output link combinations, and for a path computer to
account for such a constraint (which is not trivial).

I also would suggest the authors to consider the Virtual Link mode, that
is, representing the domain to the outside world as a bunch of PEs
interconnected by abstract (virtual) links. This approach may require more
advertisements compared to the Virtual Node mode; however, it does relieve
external path computers from handling the interface maps, plus it gives
the idea about the cost and attributes of feasible paths across the
domain.

Igor