Concept Guide

ip as-path access-list as-path-name
2 Create a AS-PATH ACL lter with a deny or permit action.
AS-PATH ACL mode
{deny | permit} as-regular-expression
3 Return to CONFIGURATION mode.
AS-PATH ACL
exit
4 Enter ROUTER BGP mode.
CONFIGURATION mode
router bgp as-number
5 Filter routes based on the criteria in the congured route map.
CONFIG-ROUTER-BGP mode
neighbor {ip-address | ipv6-address | peer-group-name} filter-list as-path-name {in | out}
Congure the following parameters:
• ip-address or ip-address or peer-group-name: enter the neighbor’s IPv4 or IPv6 address or the peer group’s name.
•
as-path-name: enter the name of a congured AS-PATH ACL.
• in: apply the AS-PATH ACL map to inbound routes.
• out: apply the AS-PATH ACL to outbound routes.
To view which commands are congured, use the show config command in CONFIGURATION ROUTER BGP mode and the show ip
as-path-access-list command in EXEC Privilege mode.
To forward all routes not meeting the AS-PATH ACL criteria, include the permit .* lter in your AS-PATH ACL.
Conguring Peer Groups
To congure multiple BGP neighbors at one time, create and populate a BGP peer group.
An advantage of peer groups is that members of a peer group inherit the conguration properties of the group and share same update
policy.
A maximum of 256 peer groups are allowed on the system.
The following tasks are involved in conguring a BGP peer group.
• Create a peer group by assigning it a name
• Adding members (neighbors) to the peer group
After you create a peer group, you can congure route policies for it. For information about conguring route policies for a peer group, refer
to Filtering BGP Routes. See Example-Conguring BGP peer groups for conguring multiple BGP neighbors and enabling peer groups.
You can use neighbor shutdown command to disable a BGP neighbor or a peer group.
1 Enter the router conguration mode and the AS number.
CONFIG mode
router bgp as-number
2 Create a peer group by assigning a name to it.
CONFIG-ROUTER-BGP mode
neighbor peer-group-name peer-group
200
Border Gateway Protocol (BGP)