Routing Policy and the BGP Decision Algorithm
A BGP router may receive paths for the same route from many neighbors. How the best path is selected is a matter of local policy. The policy within an AS must be consistent; otherwise, routing loops could occur. Conceptually, the policy and decision process is shown in Figure 11-16.
Figure 11-16. BGP's Policy and Decision Process
An incoming Routing Information Base is maintained for each peer. Incoming policy is applied to each RIB, and complying routes are passed as candidates to the BGP decision-making process. The best paths are offered as candidates to the IP forwarding table and ...
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