Enterasys Networks Security Router X-PeditionTM - Manual (Page 159)

Overview
XSR User’s Guide 6-11
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