Enterasys Networks X-PeditionTM manual BGP Path Selection Process, BGP Routing Policy

Overview

BGP Path Selection Process

BGP routers usually consider multiple paths to a destination. The BGP best path selection process decides the optimal path to install in the IP routing table and use for forwarding traffic.

Only routes that are synchronized, are free of AS loops and have a valid next-hop are considered in the selection process, as illustrated in Figure 6-8.

Figure 6-8 BGP Path Selection Algorithm

BGP Routing Policy

The XSR employs Access Control Lists (ACLs), filter lists, community lists, route maps, regular expressions, and peer groups to implement BGP routing policy, (refer to Figure 6-9. These features are described in the following pages.

Figure 6-9 BGP Routing Policy Process

XSR User’s Guide 6-11