Subject: Re: Traffic Engineering Question

From: Bora Akyol <[email-masked]>
Date: Thu, 09 Sep 1999 10:01:42 -0700

Manish

There has been some proposed extensions to ISIS and OSPF in order to flood 
resource availability in an autonomous system. *-OMP drafts continue one 
method and TE Extensions for ISIS contain another.

Regards

Bora

At 12:21 PM 9/9/99 -0400, Manish Gupta wrote:
>Hi
>
>I am wondering that how various LSRs in a network will build their
>"Resource Attribute Availability Database" ( Requirements for Traffic Engg
>over MPLS ,Internet Draft, page 25), are there any extensions to current
>IGP/EGP protocols to distribute this information to various LSRs or any
>other nmechanism to distribute this information is proposed and if so how
>this information will be kept up-to-date at all LSRs as and when resources
>are allocated and de-allocated. Furthermore, if such information is
>somehow (I dont know yet how) kept at each LSR and maintained uptodate by
>some mechanism, are we going to use some algorithm like simulated
>annealing to map these virtual topologies to underlying physical
>topologies (in the CR-LDP Process) or we have any standard mechanism for
>this mapping.
>
>Thanks
>Manish

Bora Akyol
Pluris (http://www.pluris.com)

---

From: "Radulescu-Banu, Cristina" <[email-masked]>
Date: Thu, 9 Sep 1999 13:15:45 -0400

There seems to be some drafts for OSPF TE, too (I saw at least one - I think
draft-katz-yeung-ospf-traffic-00.txt- which covers te metrics distributed in
the opaque lsa (type 9). 
Cristina

Cristina Radulescu-Banu
Redstone Communications, Inc.
5 Carlisle Road
Westford, MA 01886

[email-masked]
(978) 692 1999 x147
(978) 692 9992 fax

-----Original Message-----
From: Bora Akyol [mailto:[email-masked]]
Sent: Thursday, September 09, 1999 1:02 PM
To: Manish Gupta; [email-masked]
Subject: Re: Traffic Engineering Question 

Manish

Regards

Bora

Bora Akyol

---

From: Noel Chiappa <[email-masked]>
Date: Thu, 9 Sep 1999 14:56:03 -0400

> From: Tony Li <[email-masked]>

    >> how to "map these virtual topologies to [the] underlying physical
    >> topologies," is the general problem with which constraint-based
    >> routing is concerned. At this time, no standard mechanisms/algorithms
    >> exist for path selection using constraint-based routing.

    > It should be pointed out that there need not be any standardized (in
    > the IETF sense) algorithm for performing this function. ... Such
    > methods may vary from domain to domain.

Absolutely. In fact, it would be *wrong* to specify a standard algorithms -
each domain *ought* to have local flexibility to do it the way that works best
for them.

In fact, there's the possibility of a lively "value-added" market for small
businesses providing such algorithms - or it may only make economic sense to
use what the large switch providers provide as a standard, and that can be one
more competitive factor in the competition among them. Whatever works...

The only difficulty with the general theme above for constraint-based routing
comes if/when you try and specify MPLS paths that cross domains - but I think
that that whole class of problem is a ways down the road - let's get the
intra-domain stuff deployed and working before we go attack the much bigger
windmills of inter-domain MPLS.

	Noel