Chapter 5. Scaling BGP
BGP is designed to support not only complex routing policies, as you learned in the previous chapter, but also large networks. The Internet is a mesh of autonomous systems interconnected by EBGP—in essence, one extremely large BGP network.
The problem with big networks is that, by their nature, they are supporting many reachable end systems, and hence a great many reachable addresses. As the network grows, the routine activity on the network also grows:
End system addresses are added or removed.
Links are added or removed. ...