3Com 10014299 manual Create a Fltering Policy Based on Access List for the Peer

454CHAPTER 30: CONFIGURING BGP

By default, the route from the peer or peer group is not designated with any route policy.

10Create an filtering policy based on access list for the peer.

Table 520 Create a Fltering Policy Based on Access List for the Peer

Operation	Command
Create an filter policy based on access list	peer peer-address filter-policy
for the peer	acl-number { import export }
Remove an filter policy based on the	undo peer peer-addressfilter-policy
access list for the peer	acl-number{ import export }

By default, no route filtering policy based on IP ACL for a peer is set.

11Create BGP route filtering based on the AS path for the peer. By default, a BGP filter is disabled.

Table 521 Create a BGP Route Filtering Based on AS Path for the Peer

Operation	Command
Create a BGP route filtering based on AS	peer peer-address acl
path for the peer	aspath-list-number { import export
	}
Delete a BGP route filtering based on AS	undo peer peer-address acl
path for the peer	aspath-list-number { import export
	}

Setting the MED for the The multi-exit discriminator (MED) is the external metric of a route. It is different AS from the local preference attribute. MED is switched between ASs and the MED

that has entered the AS does not leave the AS. AS uses local attributes for its own out-site selection processing while MED attribute is used to select the best route. The route with smallest MED value is selected. When a router running BGP gets routes with the same destination address but a different next hop through different external peers, it makes a preference selection based on the MED values.

To operate the MED attribute, an access control list is used to indicate what network will be operated.

Perform the following configurations in BGP view.

Table 522 Configure the BGP MED Metric

Operation	Command
Configure MED for an AS	default-med med
Restore the default MED of an AS	undo default-med

Allow Comparing Path This command is used to compare MED values from different AS neighboring MED routes and to select the best route. The route with smaller MED value is selected.

Perform the following configurations in BGP view.

Table 523 Allow Comparing Path MED

Operation

Command