Advanced IP Network Design (CCIE Professional Development)

Scaling beyond the Core

As your network grows toward becoming an international Juggernaut, you will find that taking the load off the core routers is not enough—it is time to extend the use of BGP to the rest of the network. Three different approaches may be followed in general:

• You can divide your network into separate routing domains—connect them using eBGP.

• You can use confederations.

• You can use route reflectors.

iBGP requires a full internal mesh to ensure routing consistency. This internal mesh grows larger as BGP extends throughout the network and, of course, as the network grows. The last two approaches in the preceding list present a scalable way to reduce the number of neighbors while maintaining consistency. Dividing your network up ...