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Configuring BGP
BGP Configuration Examples
IPC-344
Cisco IOS IP Configuration Guide
To conditionally advertise a set of routes, use the following commands in router configuration mode:
ip prefix-list BLUE permit 172.16.0.0
ip prefix-list RED permit 192.168.7.0
!
route-map map1-name permit 10
match ip address prefix-list BLUE
!
route-map map2-name permit 10
match ip address prefix-list RED
!
router bgp 100
neighbor 10.89.2.33 remote-as 2051
neighbor 10.89.2.33 advertise-map map1-name non-exist-map map2-name
!
BGP Confederation Examples
The following is a sample configuration that shows several peers in a confederation. The confederation
consists of three internal autonomous systems with autonomous system numbers 6001, 6002, and 6003.
To the BGP speakers outside the confederation, the confederation looks like a normal autonomous
system with autonomous system number 60000 (specified via the bgp confederation identifier router
configuration command).
In a BGP speaker in autonomous system 6001, the bgp confederation peers router configuration
command marks the peers from autonomous systems 6002 and 6003 as special eBGP peers. Hence peers
171.69.232.55 and 171.69.232.56 will get the local preference, next hop, and MED unmodified in the
updates. The router at 160.69.69.1 is a normal eBGP speaker and the updates received by it from this
peer will be just like a normal eBGP update from a peer in autonomous system 60000.
router bgp 6001
bgp confederation identifier 60000
bgp confederation peers 6002 6003
neighbor 171.69.232.55 remote-as 6002
neighbor 171.69.232.56 remote-as 6003
neighbor 160.69.69.1 remote-as 777
In a BGP speaker in autonomous system 6002, the peers from autonomous systems 6001 and 6003 are
configured as special eBGP peers. 170.70.70.1 is a normal iBGP peer and 199.99.99.2 is a normal eBGP
peer from autonomous system 700.
router bgp 6002
bgp confederation identifier 60000
bgp confederation peers 6001 6003
neighbor 170.70.70.1 remote-as 6002
neighbor 171.69.232.57 remote-as 6001
neighbor 171.69.232.56 remote-as 6003
neighbor 199.99.99.2 remote-as 700
In a BGP speaker in autonomous system 6003, the peers from autonomous systems 6001 and 6002 are
configured as special eBGP peers. 200.200.200.200 is a normal eBGP peer from autonomous system
701.
router bgp 6003
bgp confederation identifier 60000
bgp confederation peers 6001 6002
neighbor 171.69.232.57 remote-as 6001
neighbor 171.69.232.55 remote-as 6002
neighbor 200.200.200.200 remote-as 701