Routing Protocols Problems

Routing protocols have to exchange ever increasing amounts of data, as the number of networks connected to the Internet grows.

This amount of data growing means more bandwidth for routing info is needed, more memory on routers to store routing tables, and more CPU power to process route updates.

To allow the Internet to scale better, it is divided into a set of autonomous systems (AS). Each AS handles its internal routing independently. The core routers of the Internet thus route between AS-s, not between networks.

Route aggregation (see BGP4) is used to decrease the amount of routes that need to be advertised.