BGP/IGP Network Design Principles
In the next few days, I'll write about some of the interesting topics we’ve been discussing during the last week’s fantastic on-site workshop with Ian Castleman and his team. To get us started, here’s a short video describing BGP/IGP network design principles. It’s taken straight from my Building IPv6 Service Provider Core webinar (recording), but the principles apply equally well to large enterprise networks.
- You should strive to make the core of your network as stable as possible; access network flaps should not affect the core.
- To make the core stable, propagate access network prefixes in BGP, not in core IGP.
- Core IGP should carry only the BGP next-hops and the subnets you need for network management.
- If you have to run IGP in the access network, it should not be the same IGP as the one used in the core. Redistribute access IGP’s subnets into BGP and announce just the default route (or summary routes if you are an enterprise network with local Internet breakout) into the access network IGP.
If you’re interested in IPv6, check out my IPv6-related webinars. You can find an overview of my webinars in a comprehensive roadmap available on my web site; you get access to all of them as part of the yearly subscription.