Vijay Gill wrote:
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.
agreed.... i don't advocate running igp process on your tunnels. but is-is does contribute to LS path selection during setup. but has nothing to do with the IGP process itself. thanks for the clarity, vijay.
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