What kind of routing information does BGP primarily use?

BGP, or Border Gateway Protocol, primarily relies on path attributes and policy to make routing decisions. This method allows BGP to consider the entire path that data will take, rather than just focusing on a single metric such as distance or speed. Path attributes contain various information about the route, including things like the origin of the route, the AS path (the list of autonomous systems through which the route has passed), and other properties that influence policy decisions.

The flexibility of BGP is evident as it can incorporate numerous policies to determine the preference of routes based on organizational needs or network designs. This enables network administrators to craft complex routing decisions that cater to business goals and help manage traffic effectively across the Internet.

In contrast to metrics like link metrics, hop count, or bandwidth availability—which typically represent simpler routing protocols—BGP's focus on path attributes provides a sophisticated means of managing diverse routes and ensuring optimal routing paths based on policy configurations.