Reference Guide

Border Gateway Protocol | 211
Use the show config command in CONFIGURATION ROUTER BGP mode and show ip
as-path-access-list
command in EXEC Privilege mode to view which commands are configured.
Include this filter
permit .* in your AS-PATH ACL to forward all routes not meeting the AS-PATH ACL
criteria.
Configure BGP route reflectors
BGP route reflectors are intended for Autonomous Systems with a large mesh and they reduce the amount
of BGP control traffic. With route reflection configured properly, IBGP routers are not fully meshed within
a cluster but all receive routing information.
Configure clusters of routers where one router is a concentration router and others are clients who receive
their updates from the concentration router.
Use the following commands in the CONFIGURATION ROUTER BGP mode to configure a route
reflector.
To view a route reflector configuration, use the
show config command in the CONFIGURATION
ROUTER BGP mode or
show running-config bgp in EXEC Privilege mode.
5
neighbor {ip-address |
peer-group-name} filter-list
as-path-name {in | out}
CONFIG-ROUTER-BGP Filter routes based on the criteria in the
configured route map. Configure the following
parameters:
• ip-address or peer-group-name: enter the
neighbor’s IP address or the peer group’s
name.
• as-path-name: enter the name of a
configured AS-PATH ACL.
• in: apply the AS-PATH ACL map to inbound
routes.
• out: apply the AS-PATH ACL to outbound
routes.
Note: Using Multipath and Add Path simultaneously in a Route Reflector is not recommended.
Command Syntax Command Mode Purpose
bgp cluster-id cluster-id CONFIG-ROUTER-BGP Assign an ID to a router reflector cluster.
You can have multiple clusters in an AS.
neighbor {ip-address |
peer-group-name}
route-reflector-client
CONFIG-ROUTER-BGP Configure the local router as a route reflector and the
neighbor or peer group identified is the route reflector
client.
Step Command Syntax Command Mode Purpose