Reference Guide

Border Gateway Protocol IPv4 (BGPv4) | 229
Use the show config command in CONFIGURATION ROUTER BGP mode to view the BGP
configuration. Use the
show route-map command in EXEC Privilege mode to view a route map
configuration.
Use these commands in the following sequence, beginning in the CONFIGURATION mode to filter routes
based on AS-PATH information.
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.
neighbor {ip-address |
peer-group-name} route-map
map-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.
•
map-name: enter the name of a
configured route map.
•
in: apply the route map to inbound
routes.
• out: apply the route map to outbound
routes.
Step Command Syntax Command Mode Purpose
1
ip as-path access-list
as-path-name
CONFIGURATION Create a AS-PATH ACL and assign it a name.
2
{deny | permit}
as-regular-expression
AS-PATH ACL Create a AS-PATH ACL filter with a deny or
permit action.
3
exit
AS-PATH ACL Return to the CONFIGURATION mode.
4
router bgp as-number CONFIGURATION Enter ROUTER BGP mode.
5
neighbor {ip-address |
peer-group-name} filter-list
as-path-name {in | out}
CONFIG-ROUTER-B
GP
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.
Step Command Syntax Command Mode Purpose