Overview
BGP's main strength is its capability to impose routing policy, primarily through route maps that manipulate BGP path attributes. These attributes allow for very precise and complex policy implementation. However, as ISP's scale their BGP routing to include dozens, and even hundreds of routers, BGP's precision can become an administrative nightmare.

The Cisco IOS offers several methods to make scaling BGP easier on administrators and on the BGP routers themselves. This chapter discusses the following key features needed to simplify and streamline large BGP domains: route reflectors, route filtering, the Community attribute, and peer groups. Moreover, we will examine BGP scalability issues such as redundancy, load balancing, multihomed connections, and route redistribution.