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Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-08
Chapter 40 Configuring IP Unicast Routing
Configuring BGP
path, community, and network numbers. Autonomous system path matching requires the
match
as-path
access-lis
t route-map command, community based matching requires the
match community-list
route-map command, and network-based matching requires the
ip access-list
global configuration
command.
Beginning in privileged EXEC mode, follow these steps to apply a per-neighbor route map:
Use the
no neighbor distribute-list
command to remove the access list from the neighbor. Use the
no
neighbor route-map
map-tag
router configuration command to remove the route map from the
neighbor.
Another method of filtering is to specify an access list filter on both incoming and outbound updates,
based on the BGP autonomous system paths. Each filter is an access list based on regular expressions.
(See the “Regular Expressions” appendix in the
Cisco IOS Dial Technologies Command Reference,
Release 12.2
for more information on forming regular expressions.) To use this method, define an
autonomous system path access list, and apply it to updates to and from particular neighbors.
Beginning in privileged EXEC mode, follow these steps to configure BGP path filtering:
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
router bgp
autonomous-system
Enable a BGP routing process, assign it an AS number, and enter
router configuration mode.
Step 3
neighbor
{
ip-address
|
peer-group name
}
distribute-list
{
access-list-number
|
name
}
{
in
|
out
}
(Optional) Filter BGP routing updates to or from neighbors as
specified in an access list.
Note
You can also use the
neighbor prefix-list
router
configuration command to filter updates, but you cannot use
both commands to configure the same BGP peer.
Step 4
neighbor
{
ip-address
|
peer-group name
}
route-map
map-tag
{
in
|
out
}
(Optional) Apply a route map to filter an incoming or outgoing
route.
Step 5
end
Return to privileged EXEC mode.
Step 6
show ip bgp neighbors
Verify the configuration.
Step 7
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
ip as-path access-list
access-list-number
{
permit
|
deny
}
as-regular-expressions
Define a BGP-related access list.
Step 3
router bgp
autonomous-system
Enter BGP router configuration mode.
Step 4
neighbor
{
ip-address
|
peer-group name
}
filter-list
{
access-list-number
|
name
} {
in
|
out
|
weight
weight
}
Establish a BGP filter based on an access list.
Step 5
end
Return to privileged EXEC mode.
Step 6
show ip bgp neighbors
[
paths
regular-expression
]
Verify the configuration.
Step 7
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Summary of Contents for Catalyst 3750-E Series
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Page 52: ...lii Catalyst 3750 E and 3560 E Switch Software Configuration Guide OL 9775 08 Preface ...
Page 1414: ...Index IN 58 Catalyst 3750 E and 3560 E Switch Software Configuration Guide OL 9775 08 ...
