IS-IS reference
Vijay Gill
wrath at cs.umbc.edu
Tue Sep 14 19:28:32 UTC 1999
On Tue, 14 Sep 1999, Dave Cooper wrote:
> 1. if you are going to scale a large national backbone, limit as much
> as you can in your IGP. the less fluctation in flooding protocols, the
> better. and since most backbones run on a single area (on the main
> IGP process) or level-2 only, then fluctuations cause headaches for
> all participating routers. this is especially so when you have a
> full layer-2 mesh or a full MPLS mesh.
A full mpls mesh should not be a problem as instantiated LSP's are
probably not going to be in your igp. Running an IGP over an (opaque) LSP
adds a lot to your complexity without delivering any major benefits.
You can add hierarchy to your topology obviating a need for a full mesh at
the L2 level.
Hierarchy can solve almost any scaling issue. Hierarchy in BGP through
confederations/RR, hierarchy in your IGP and hierarchy in your physical
circuit layout.
/vijay
More information about the NANOG
mailing list