The following example configurations show
how to enable BGP and set up some peer groups. These examples are
not comprehensive directions. They are intended to give you some guidance
with typical configurations.
Example of Enabling
BGP (Router 1)
R1# conf
R1(conf)#int loop 0
R1(conf-if-lo-0)#ip address 192.168.128.1/24
R1(conf-if-lo-0)#no shutdown
R1(conf-if-lo-0)#show config
!
interface Loopback 0
ip address 192.168.128.1/24
no shutdown
R1(conf-if-lo-0)#int gig 1/21
R1(conf-if-gi-1/21)#ip address 10.0.1.21/24
R1(conf-if-gi-1/21)#no shutdown
R1(conf-if-gi-1/21)#show config
!
interface GigabitEthernet 1/21
ip address 10.0.1.21/24
no shutdown
R1(conf-if-gi-1/21)#int gig 1/31
R1(conf-if-gi-1/31)#ip address 10.0.3.31/24
R1(conf-if-gi-1/31)#no shutdown
R1(conf-if-gi-1/31)#show config
!
interface GigabitEthernet 1/31
ip address 10.0.3.31/24
no shutdown
R1(conf-if-gi-1/31)#router bgp 99
R1(conf-router_bgp)#network 192.168.128.0/24
R1(conf-router_bgp)#neighbor 192.168.128.2 remote 99
R1(conf-router_bgp)#neighbor 192.168.128.2 no shut
R1(conf-router_bgp)#neighbor 192.168.128.2 update-source loop 0
R1(conf-router_bgp)#neighbor 192.168.128.3 remote 100
R1(conf-router_bgp)#neighbor 192.168.128.3 no shut
R1(conf-router_bgp)#neighbor 192.168.128.3 update-source loop 0
R1(conf-router_bgp)#show config
!
router bgp 99
network 192.168.128.0/24
neighbor 192.168.128.2 remote-as 99
neighbor 192.168.128.2 update-source Loopback 0
neighbor 192.168.128.2 no shutdown
neighbor 192.168.128.3 remote-as 100
neighbor 192.168.128.3 update-source Loopback 0
neighbor 192.168.128.3 no shutdown
R1(conf-router_bgp)#end
R1#
R1#show ip bgp summary
BGP router identifier 192.168.128.1, local AS number 99
BGP table version is 4, main routing table version 4
4 network entrie(s) using 648 bytes of memory
6 paths using 408 bytes of memory
BGP-RIB over all using 414 bytes of memory
3 BGP path attribute entrie(s) using 144 bytes of memory
2 BGP AS-PATH entrie(s) using 74 bytes of memory
2 neighbor(s) using 8672 bytes of memory
Neighbor AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/Pfx
192.168.128.2 99 4 5 4 0 0 00:00:32 1
192.168.128.3 100 5 4 1 0 0 00:00:09 4
R1#
R2# conf
R2(conf)#int loop 0
R2(conf-if-lo-0)#ip address 192.168.128.2/24
R2(conf-if-lo-0)#no shutdown
R2(conf-if-lo-0)#show config
!
interface Loopback 0
ip address 192.168.128.2/24
no shutdown
R2(conf-if-lo-0)#int gig 2/11
R2(conf-if-gi-2/11)#ip address 10.0.1.22/24
R2(conf-if-gi-2/11)#no shutdown
R2(conf-if-gi-2/11)#show config
!
interface GigabitEthernet 2/11
ip address 10.0.1.22/24
no shutdown
R2(conf-if-gi-2/11)#int gig 2/31
R2(conf-if-gi-2/31)#ip address 10.0.2.2/24
R2(conf-if-gi-2/31)#no shutdown
R2(conf-if-gi-2/31)#show config
!
interface GigabitEthernet 2/31
ip address 10.0.2.2/24
no shutdown
R2(conf-if-gi-2/31)#
R2(conf-if-gi-2/31)#router bgp 99
R2(conf-router_bgp)#network 192.168.128.0/24
R2(conf-router_bgp)#neighbor 192.168.128.1 remote 99
R2(conf-router_bgp)#neighbor 192.168.128.1 no shut
R2(conf-router_bgp)#neighbor 192.168.128.1 update-source loop 0
R2(conf-router_bgp)#neighbor 192.168.128.3 remote 100
R2(conf-router_bgp)#neighbor 192.168.128.3 no shut
R2(conf-router_bgp)#neighbor 192.168.128.3 update loop 0
R2(conf-router_bgp)#show config
!
router bgp 99
bgp router-id 192.168.128.2
network 192.168.128.0/24
bgp graceful-restart
neighbor 192.168.128.1 remote-as 99
neighbor 192.168.128.1 update-source Loopback 0
neighbor 192.168.128.1 no shutdown
neighbor 192.168.128.3 remote-as 100
neighbor 192.168.128.3 update-source Loopback 0
neighbor 192.168.128.3 no shutdown
R2(conf-router_bgp)#end
R2#show ip bgp summary
BGP router identifier 192.168.128.2, local AS number 99
BGP table version is 1, main routing table version 1
1 network entrie(s) using 132 bytes of memory
3 paths using 204 bytes of memory
BGP-RIB over all using 207 bytes of memory
2 BGP path attribute entrie(s) using 128 bytes of memory
2 BGP AS-PATH entrie(s) using 90 bytes of memory
2 neighbor(s) using 9216 bytes of memory
Neighbor AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/Pfx
192.168.128.1 99 40 35 1 0 0 00:01:05 1
192.168.128.3 100 4 4 1 0 0 00:00:16 1
R2#
R3# conf
R3(conf)#
R3(conf)#int loop 0
R3(conf-if-lo-0)#ip address 192.168.128.3/24
R3(conf-if-lo-0)#no shutdown
R3(conf-if-lo-0)#show config
!
interface Loopback 0
ip address 192.168.128.3/24
no shutdown
R3(conf-if-lo-0)#int gig 3/11
R3(conf-if-gi-3/11)#ip address 10.0.3.33/24
R3(conf-if-gi-3/11)#no shutdown
R3(conf-if-gi-3/11)#show config
!
interface GigabitEthernet 3/11
ip address 10.0.3.33/24
no shutdown
R3(conf-if-lo-0)#int gig 3/21
R3(conf-if-gi-3/21)#ip address 10.0.2.3/24
R3(conf-if-gi-3/21)#no shutdown
R3(conf-if-gi-3/21)#show config
!
interface GigabitEthernet 3/21
ip address 10.0.2.3/24
no shutdown
R3(conf-if-gi-3/21)#
R3(conf-if-gi-3/21)#router bgp 100
R3(conf-router_bgp)#show config
!
router bgp 100
R3(conf-router_bgp)#network 192.168.128.0/24
R3(conf-router_bgp)#neighbor 192.168.128.1 remote 99
R3(conf-router_bgp)#neighbor 192.168.128.1 no shut
R3(conf-router_bgp)#neighbor 192.168.128.1 update-source loop 0
R3(conf-router_bgp)#neighbor 192.168.128.2 remote 99
R3(conf-router_bgp)#neighbor 192.168.128.2 no shut
R3(conf-router_bgp)#neighbor 192.168.128.2 update loop 0
R3(conf-router_bgp)#show config
!
router bgp 100
network 192.168.128.0/24
neighbor 192.168.128.1 remote-as 99
neighbor 192.168.128.1 update-source Loopback 0
neighbor 192.168.128.1 no shutdown
neighbor 192.168.128.2 remote-as 99
neighbor 192.168.128.2 update-source Loopback 0
neighbor 192.168.128.2 no shutdown
R3(conf)#end
R3#show ip bgp summary
BGP router identifier 192.168.128.3, local AS number 100
BGP table version is 1, main routing table version 1
1 network entrie(s) using 132 bytes of memory
3 paths using 204 bytes of memory
BGP-RIB over all using 207 bytes of memory
2 BGP path attribute entrie(s) using 128 bytes of memory
2 BGP AS-PATH entrie(s) using 90 bytes of memory
2 neighbor(s) using 9216 bytes of memory
Neighbor AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/Pfx
192.168.128.1 99 24 25 1 0 0 00:14:20 1
192.168.128.2 99 14 14 1 0 0 00:10:22 1
R3#
R1#conf
R1(conf)#router bgp 99
R1(conf-router_bgp)# network 192.168.128.0/24
R1(conf-router_bgp)# neighbor AAA peer-group
R1(conf-router_bgp)# neighbor AAA no shutdown
R1(conf-router_bgp)# neighbor BBB peer-group
R1(conf-router_bgp)# neighbor BBB no shutdown
R1(conf-router_bgp)# neighbor 192.168.128.2 peer-group AAA
R1(conf-router_bgp)# neighbor 192.168.128.3 peer-group BBB
R1(conf-router_bgp)#
R1(conf-router_bgp)#show config
!
router bgp 99
network 192.168.128.0/24
neighbor AAA peer-group
neighbor AAA no shutdown
neighbor BBB peer-group
neighbor BBB no shutdown
neighbor 192.168.128.2 remote-as 99
neighbor 192.168.128.2 peer-group AAA
neighbor 192.168.128.2 update-source Loopback 0
neighbor 192.168.128.2 no shutdown
neighbor 192.168.128.3 remote-as 100
neighbor 192.168.128.3 peer-group BBB
neighbor 192.168.128.3 update-source Loopback 0
neighbor 192.168.128.3 no shutdown
R1#
R1#show ip bgp summary
BGP router identifier 192.168.128.1, local AS number 99
BGP table version is 1, main routing table version 1
1 network entrie(s) using 132 bytes of memory
3 paths using 204 bytes of memory
BGP-RIB over all using 207 bytes of memory
2 BGP path attribute entrie(s) using 96 bytes of memory
2 BGP AS-PATH entrie(s) using 74 bytes of memory
2 neighbor(s) using 8672 bytes of memory
Neighbor AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/Pfx
192.168.128.2 99 23 24 1 0 (0) 00:00:17 1
192.168.128.3 100 30 29 1 0 (0) 00:00:14 1
!
R1#show ip bgp neighbors
BGP neighbor is 192.168.128.2, remote AS 99, internal link
Member of peer-group AAA for session parameters
BGP version 4, remote router ID 192.168.128.2
BGP state ESTABLISHED, in this state for 00:00:37
Last read 00:00:36, last write 00:00:36
Hold time is 180, keepalive interval is 60 seconds
Received 23 messages, 0 in queue
2 opens, 0 notifications, 2 updates
19 keepalives, 0 route refresh requests
Sent 24 messages, 0 in queue
2 opens, 1 notifications, 2 updates
19 keepalives, 0 route refresh requests
Minimum time between advertisement runs is 5 seconds
Minimum time before advertisements start is 0 seconds
Capabilities received from neighbor for IPv4 Unicast :
MULTIPROTO_EXT(1)
ROUTE_REFRESH(2)
CISCO_ROUTE_REFRESH(128)
Capabilities advertised to neighbor for IPv4 Unicast :
MULTIPROTO_EXT(1)
ROUTE_REFRESH(2)
CISCO_ROUTE_REFRESH(128)
Update source set to Loopback 0
Peer active in peer-group outbound optimization
For address family: IPv4 Unicast
BGP table version 1, neighbor version 1
Prefixes accepted 1 (consume 4 bytes), withdrawn 0 by peer
Prefixes advertised 1, denied 0, withdrawn 0 from peer
Connections established 2; dropped 1
Last reset 00:00:57, due to user reset
Notification History
'Connection Reset' Sent : 1 Recv: 0
Last notification (len 21) sent 00:00:57 ago
ffffffff ffffffff ffffffff ffffffff 00150306 00000000
Local host: 192.168.128.1, Local port: 179
Foreign host: 192.168.128.2, Foreign port: 65464
BGP neighbor is 192.168.128.3, remote AS 100, external link
Member of peer-group BBB for session parameters
BGP version 4, remote router ID 192.168.128.3
BGP state ESTABLISHED, in this state for 00:00:37
Last read 00:00:36, last write 00:00:36
Hold time is 180, keepalive interval is 60 seconds
Received 30 messages, 0 in queue
4 opens, 2 notifications, 4 updates
20 keepalives, 0 route refresh requests
Sent 29 messages, 0 in queue
4 opens, 1 notifications, 4 updates
20 keepalives, 0 route refresh requests
Minimum time between advertisement runs is 30 seconds
Minimum time before advertisements start is 0 seconds
Capabilities received from neighbor for IPv4 Unicast :
MULTIPROTO_EXT(1)
Capabilities received from neighbor for IPv4 Unicast :
MULTIPROTO_EXT(1)
ROUTE_REFRESH(2)
CISCO_ROUTE_REFRESH(128)
Update source set to Loopback 0
Peer active in peer-group outbound optimization
For address family: IPv4 Unicast
BGP table version 1, neighbor version 1
Prefixes accepted 1 (consume 4 bytes), withdrawn 0 by peer
Prefixes advertised 1, denied 0, withdrawn 0 from peer
Connections established 4; dropped 3
Last reset 00:00:54, due to user reset
R1#
R2#conf
R2(conf)#router bgp 99
R2(conf-router_bgp)# neighbor CCC peer-group
R2(conf-router_bgp)# neighbor CC no shutdown
R2(conf-router_bgp)# neighbor BBB peer-group
R2(conf-router_bgp)# neighbor BBB no shutdown
R2(conf-router_bgp)# neighbor 192.168.128.1 peer AAA
R2(conf-router_bgp)# neighbor 192.168.128.1 no shut
R2(conf-router_bgp)# neighbor 192.168.128.3 peer BBB
R2(conf-router_bgp)# neighbor 192.168.128.3 no shut
R2(conf-router_bgp)#show conf
!
router bgp 99
network 192.168.128.0/24
neighbor AAA peer-group
neighbor AAA no shutdown
neighbor BBB peer-group
neighbor BBB no shutdown
neighbor 192.168.128.1 remote-as 99
neighbor 192.168.128.1 peer-group CCC
neighbor 192.168.128.1 update-source Loopback 0
neighbor 192.168.128.1 no shutdown
neighbor 192.168.128.3 remote-as 100
neighbor 192.168.128.3 peer-group BBB
neighbor 192.168.128.3 update-source Loopback 0
neighbor 192.168.128.3 no shutdown
R2(conf-router_bgp)#end
R2#
R2#show ip bgp summary
BGP router identifier 192.168.128.2, local AS number 99
BGP table version is 2, main routing table version 2
1 network entrie(s) using 132 bytes of memory
3 paths using 204 bytes of memory
BGP-RIB over all using 207 bytes of memory
2 BGP path attribute entrie(s) using 128 bytes of memory
2 BGP AS-PATH entrie(s) using 90 bytes of memory
2 neighbor(s) using 9216 bytes of memory
Neighbor AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/Pfx
192.168.128.1 99 140 136 2 0 (0) 00:11:24 1
192.168.128.3 100 138 140 2 0 (0) 00:18:31 1
R2#show ip bgp neighbor
BGP neighbor is 192.168.128.1, remote AS 99, internal link
Member of peer-group AAA for session parameters
BGP version 4, remote router ID 192.168.128.1
BGP state ESTABLISHED, in this state for 00:11:42
Last read 00:00:38, last write 00:00:38
Hold time is 180, keepalive interval is 60 seconds
Received 140 messages, 0 in queue
6 opens, 2 notifications, 19 updates
113 keepalives, 0 route refresh requests
Sent 136 messages, 0 in queue
12 opens, 3 notifications, 6 updates
115 keepalives, 0 route refresh requests
Minimum time between advertisement runs is 5 seconds
Minimum time before advertisements start is 0 seconds
R3#conf
R3(conf)#router bgp 100
R3(conf-router_bgp)# neighbor AAA peer-group
R3(conf-router_bgp)# neighbor AAA no shutdown
R3(conf-router_bgp)# neighbor CCC peer-group
R3(conf-router_bgp)# neighbor CCC no shutdown
R3(conf-router_bgp)# neighbor 192.168.128.2 peer-group BBB
R3(conf-router_bgp)# neighbor 192.168.128.2 no shutdown
R3(conf-router_bgp)# neighbor 192.168.128.1 peer-group BBB
R3(conf-router_bgp)# neighbor 192.168.128.1 no shutdown
R3(conf-router_bgp)#
R3(conf-router_bgp)#end
R3#show ip bgp summary
BGP router identifier 192.168.128.3, local AS number 100
BGP table version is 1, main routing table version 1
1 network entrie(s) using 132 bytes of memory
3 paths using 204 bytes of memory
BGP-RIB over all using 207 bytes of memory
2 BGP path attribute entrie(s) using 128 bytes of memory
2 BGP AS-PATH entrie(s) using 90 bytes of memory
2 neighbor(s) using 9216 bytes of memory
Neighbor AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/Pfx
192.168.128.1 99 93 99 1 0 (0) 00:00:15 1
192.168.128.2 99 122 120 1 0 (0) 00:00:11 1
R3#show ip bgp neighbor
BGP neighbor is 192.168.128.1, remote AS 99, external link
Member of peer-group BBB for session parameters
BGP version 4, remote router ID 192.168.128.1
BGP state ESTABLISHED, in this state for 00:00:21
Last read 00:00:09, last write 00:00:08
Hold time is 180, keepalive interval is 60 seconds
Received 93 messages, 0 in queue
5 opens, 0 notifications, 5 updates
83 keepalives, 0 route refresh requests
Sent 99 messages, 0 in queue
5 opens, 4 notifications, 5 updates
85 keepalives, 0 route refresh requests
Minimum time between advertisement runs is 30 seconds
Minimum time before advertisements start is 0 seconds
Capabilities received from neighbor for IPv4 Unicast :
MULTIPROTO_EXT(1)
ROUTE_REFRESH(2)
CISCO_ROUTE_REFRESH(128)
Capabilities advertised to neighbor for IPv4 Unicast :
MULTIPROTO_EXT(1)
ROUTE_REFRESH(2)
CISCO_ROUTE_REFRESH(128)
Update source set to Loopback 0
Peer active in peer-group outbound optimization
For address family: IPv4 Unicast
BGP table version 1, neighbor version 1
Prefixes accepted 1 (consume 4 bytes), withdrawn 0 by peer
Prefixes advertised 1, denied 0, withdrawn 0 from peer
Capabilities received from neighbor for IPv4 Unicast :
MULTIPROTO_EXT(1)
ROUTE_REFRESH(2)
CISCO_ROUTE_REFRESH(128)
Capabilities advertised to neighbor for IPv4 Unicast :
MULTIPROTO_EXT(1)
ROUTE_REFRESH(2)
CISCO_ROUTE_REFRESH(128)
Update source set to Loopback 0
Peer active in peer-group outbound optimization
For address family: IPv4 Unicast
BGP table version 2, neighbor version 2
Prefixes accepted 1 (consume 4 bytes), withdrawn 0 by peer
Prefixes advertised 1, denied 0, withdrawn 0 from peer
Connections established 6; dropped 5
Last reset 00:12:01, due to Closed by neighbor
Notification History
'HOLD error/Timer expired' Sent : 1 Recv: 0
'Connection Reset' Sent : 2 Recv: 2
Last notification (len 21) received 00:12:01 ago
ffffffff ffffffff ffffffff ffffffff 00150306 00000000
Local host: 192.168.128.2, Local port: 65464
Foreign host: 192.168.128.1, Foreign port: 179
BGP neighbor is 192.168.128.3, remote AS 100, external link
Member of peer-group BBB for session parameters
BGP version 4, remote router ID 192.168.128.3
BGP state ESTABLISHED, in this state for 00:18:51
Last read 00:00:45, last write 00:00:44
Hold time is 180, keepalive interval is 60 seconds
Received 138 messages, 0 in queue
7 opens, 2 notifications, 7 updates
122 keepalives, 0 route refresh requests
Sent 140 messages, 0 in queue
7 opens, 4 notifications, 7 updates
122 keepalives, 0 route refresh requests
Minimum time between advertisement runs is 30 seconds
Minimum time before advertisements start is 0 seconds
Capabilities advertised to neighbor for IPv4 Unicast :
MULTIPROTO_EXT(1)
Capabilities received from neighbor for IPv4 Unicast :
MULTIPROTO_EXT(1)
ROUTE_REFRESH(2)
CISCO_ROUTE_REFRESH(128)
ROUTE_REFRESH(2)
CISCO_ROUTE_REFRESH(128)
Update source set to Loopback 0
Peer active in peer-group outbound optimization
For address family: IPv4 Unicast
BGP table version 2, neighbor version 2
Prefixes accepted 1 (consume 4 bytes), withdrawn 0 by peer
Prefixes advertised 1, denied 0, withdrawn 0 from peer