Worldly Thoughts - Regionalizing Peering

The model scales well, imho. Regionalize your network into
pieces. Apply each of the pieces into 1 or more proximities to a

Been there, done that.... I've already stated my view on the
scalability of such arrangements.

Benefit: I gain low latency transit to most everyone.

Drawback: It is technically challenging to create an automate
system to regionalize and create appropriate filter lists.

It also complicates every peering relationship and multi-homed
customer connection, as you have to worry about both multiple
external AS's and your internal routing redistribution from all
of these regional routing clouds.

If you presume a fairly dense set of interconnects among transit
providers, then you're not going to get a significant improvement
in latency despite the added complexity.


The level of complication is dependant on how the network is structured.
For example, in a topology which reflects internal routes between
access/service and core nodes, it will be treated as a single AS, or as an
alternate it can be treated as external. This is because you've
distributed the processing throughout the majority nodes in the network,
rather than a design which is doing the processing on the edges of the

This greatly eases the amount of constant re-configuration and work that
is required to connect to a dense set of exchange points.