I have been doing a lot of research recently on operating networks with partial tables and a default to the rest of the world. Seems like an easy enough approach for regional networks where you have maybe only 1 upstream transit and some peering. 

I come to NANOG to get feedback from others who may be doing this. We have 3 upstream transit providers and PNI and public peers in 2 locations. It'd obviously be easy to transition to doing partial routes for just the peers, etc, but I'm not sure where to draw the line on the transit providers.

I've thought of straight preferencing one over another. I've thought of using BGP filtering and community magic to basically allow Transit AS + 1 additional AS (Transit direct customer) as specific routes, with summarization to default for the rest. I'm sure there are other thoughts that I haven't had about this as well....

And before I get asked why not just run full tables, I'm looking at regional approaches to being able to use smaller, less powerful routers (or even layer3 switches) to run some areas of the network where we can benefit from summarization and full tables are really overkill. 

James W. Breeden

Managing Partner

 

Arenal Group: Arenal Consulting Group | Acilis Telecom | Pines Media

PO Box 1063 | Smithville, TX 78957

Email: james@arenalgroup.co | office 512.360.0000 | www.arenalgroup.co