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Cell Relay Retreat>MPLS WG Archive>month:2001-Jan> msg00076



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Some queries

  • From: Curtis Villamizar <curtis@workhorse.fictitious.org>
  • Date: Mon, 08 Jan 2001 13:01:39 -0500
  • cc: curtis@avici.com, "Cheng-Yin Lee" <leecy@nortelnetworks.com>, "Faisal S. Naik" <faisal@hamdard.net.pk>, "mpls uunet" <mpls@UU.NET>, zaziz@cisco.com, prasanna@csa.iisc.ernet.in


In message <002c01c07991$b85bb2d0$a0b7010a@winstar.com>, "Yi Chu" writes:
> ATM is a link layer protocol and should be treated as such.  It can be
> stretched to support TE, to a limited fashion (region to region, e.g.).
> Full mesh of 1000 nodes is not the fault of ATM as a protocol, it is the
> failure of not doing proper capacity engineering, IMHO.
> 
> yi


It is a reality for ISPs with 500-1,000 access routers.  Since the
1,000 node full mesh would work really badly, ISPs break networks into
10s of regions, then they have on the order of a 100 node full mesh
withing the region though flooding within the core becomes manageable.
They also lose edge-to-edge TE capability that with hierarchical
MPLS-TE they will get back (when hierarchical MPLS-TE is ready).

As Vijay and Jim pointed out earlier, the limit of OC12c on router ATM
interfaces caused this hierarchical plan to start to break down around
1997 or 1998, fueling a sense of urgency to replace ATM in the core.

Curtis