User guide

Configuring BGP Routing Policies
OmniSwitch AOS Release 7 Advanced Routing Configuration Guide March 2015 page 4-87
Policies that should affect routes learned from a peer use the in- prefix, and policies that affect routes
being advertised to a peer use the out- prefix.
Assigning Inbound and Outbound Policies to an IPv4 Peer
The following sections describes assigning various policies to an IPv4 BGP peer.
Assigning In and Outbound AS Path Policies
AS path policies filter routes based on matches made to a set AS list in the route. An AS list is a list of all
the ASs the route crosses until its destination. To filter routes learned from a peer by the AS list, enter the
peer’s IP address with the ip bgp neighbor in-aspathlist command as shown:
-> ip bgp neighbor 172.22.2.0 in-aspathlist aspathfilter
The AS path policy aspathfilter must be previously created using the ip bgp policy aspath-list command.
To attach the same policy on route advertisements to the peer, enter the peer IP address with the ip bgp
neighbor out-aspathlist command, as shown:
-> ip bgp neighbor 172.22.2.0 out-aspathlist aspathfilter
Assigning In and Outbound Community List Policies
Community list policies filter routes based on matches made to a list of communities of which the route is
a member. Communities group routes by attaching labels to them specifying a behavior (such as no
export).
To filter routes learned from a peer by the community list, enter the peer’s IP address with the ip bgp
neighbor in-communitylist command as shown:
-> ip bgp neighbor 172.22.2.0 in-communitylist commlistfilter
The community list policy commlistfilter must be previously created using the ip bgp policy
community-list command.
To assign the same policy to route advertisements to the peer, enter the peer IP address with the ip bgp
neighbor out-communitylist command, as shown:
-> ip bgp neighbor 172.22.2.0 out-communitylist commlistfilter
Assigning In and Outbound Prefix List Policies
Prefix list policies filter routes based on a specific routing network, using an IP address or a series of IP
addresses.
To filter routes learned from a peer by the prefix list, enter the peer’s IP address with the ip bgp neighbor
in-prefixlist command as shown:
-> ip bgp neighbor 172.22.2.0 in-prefixlist prefixfilter
Assigns an inbound or outbound policy
map to an IPv6 BGP peer.
ipv6 bgp neighbor route-map
Invokes an inbound or outbound policy
reconfiguration for an IPv6 BGP peer.
ipv6 bgp neighbor clear soft
BGP Attribute Command