iBGP maximum-path
設定
・物理：192.168.xy.0/24
・Loopback：x.x.x.x/24
・iosv6,8,9,10間：10.1.1.x/24
目標はiosv-3のルーティングテーブルにて10.1.1.0/24宛の経路が３つになること。
before
show ip route
iosv-3#sh ip ro | b Gate
Gateway of last resort is not set
1.0.0.0/32 is subnetted, 1 subnets
O 1.1.1.1 [110/2] via 192.168.13.1, 00:40:36, GigabitEthernet0/1
2.0.0.0/32 is subnetted, 1 subnets
O 2.2.2.2 [110/2] via 192.168.23.2, 00:39:56, GigabitEthernet0/2
3.0.0.0/32 is subnetted, 1 subnets
C 3.3.3.3 is directly connected, Loopback0
5.0.0.0/32 is subnetted, 1 subnets
O 5.5.5.5 [110/2] via 192.168.35.5, 00:36:51, GigabitEthernet0/0
7.0.0.0/32 is subnetted, 1 subnets
O 7.7.7.7 [110/2] via 192.168.37.7, 00:37:11, GigabitEthernet0/3
10.0.0.0/24 is subnetted, 1 subnets
B 10.1.1.0 [200/0] via 1.1.1.1, 00:00:08
192.168.13.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.13.0/24 is directly connected, GigabitEthernet0/1
L 192.168.13.3/32 is directly connected, GigabitEthernet0/1
192.168.23.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.23.0/24 is directly connected, GigabitEthernet0/2
L 192.168.23.3/32 is directly connected, GigabitEthernet0/2
192.168.35.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.35.0/24 is directly connected, GigabitEthernet0/0
L 192.168.35.3/32 is directly connected, GigabitEthernet0/0
192.168.37.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.37.0/24 is directly connected, GigabitEthernet0/3
L 192.168.37.3/32 is directly connected, GigabitEthernet0/3show ip bgp
iosv-3#sh ip bgp
BGP table version is 4, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
t secondary path,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
* i 10.1.1.0/24 2.2.2.2 0 100 0 200 i
* i 5.5.5.5 0 100 0 200 i
*>i 1.1.1.1 0 100 0 200 iafter
設定
R3(config)#router bgp 100
R3(config-router)#maximum-paths ibgp 3結果
iosv-3#sh ip ro | b Gate
Gateway of last resort is not set
1.0.0.0/32 is subnetted, 1 subnets
O 1.1.1.1 [110/2] via 192.168.13.1, 00:27:06, GigabitEthernet0/1
2.0.0.0/32 is subnetted, 1 subnets
O 2.2.2.2 [110/2] via 192.168.23.2, 00:26:26, GigabitEthernet0/2
3.0.0.0/32 is subnetted, 1 subnets
C 3.3.3.3 is directly connected, Loopback0
5.0.0.0/32 is subnetted, 1 subnets
O 5.5.5.5 [110/2] via 192.168.35.5, 00:23:21, GigabitEthernet0/0
7.0.0.0/32 is subnetted, 1 subnets
O 7.7.7.7 [110/2] via 192.168.37.7, 00:23:41, GigabitEthernet0/3
10.0.0.0/24 is subnetted, 1 subnets
B 10.1.1.0 [200/0] via 5.5.5.5, 00:00:22
[200/0] via 2.2.2.2, 00:00:22
[200/0] via 1.1.1.1, 00:00:22
192.168.13.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.13.0/24 is directly connected, GigabitEthernet0/1
L 192.168.13.3/32 is directly connected, GigabitEthernet0/1
192.168.23.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.23.0/24 is directly connected, GigabitEthernet0/2
L 192.168.23.3/32 is directly connected, GigabitEthernet0/2
192.168.35.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.35.0/24 is directly connected, GigabitEthernet0/0
L 192.168.35.3/32 is directly connected, GigabitEthernet0/0
192.168.37.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.37.0/24 is directly connected, GigabitEthernet0/3
L 192.168.37.3/32 is directly connected, GigabitEthernet0/3iosv-3#sh ip bgp
BGP table version is 5, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
t secondary path,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
*mi 10.1.1.0/24 2.2.2.2 0 100 0 200 i
*mi 5.5.5.5 0 100 0 200 i
*>i 1.1.1.1 0 100 0 200 iルーティングテーブルでのネクストホップが増えた。
BGPテーブルでは”m”コードが追加された。
参考
Chapter: iBGP Multipath Load Sharing