前回OSPFのsummary addressコマンドで集約をおこなったが、
そもそもその経路はEIGRPルータから広報されている経路であった。
前回は自社ではOSPFルータしか設定できないという前提であったが、
EIGRPルータで集約する場合を考えてみよう。
R4
R4#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R4(config)#interface gigabitEthernet 2/0
R4(config-if)#ip summary-address eigrp 1 ?
A.B.C.D IP address
R4(config-if)#ip summary-address eigrp 1 10.0.0.0 ?
A.B.C.D IP network mask
R4(config-if)#ip summary-address eigrp 1 10.0.0.0 255.255.248.0
R4(config-if)#end
R4#
*Feb 11 14:33:39.611: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor 20.0.1.254 (GigabitEthernet2/0) is resync: summary configured
*Feb 11 14:33:40.263: %SYS-5-CONFIG_I: Configured from console by console
R4#
R4#sho ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
4.0.0.0/32 is subnetted, 1 subnets
C 4.4.4.4 is directly connected, Loopback0
20.0.0.0/24 is subnetted, 1 subnets
C 20.0.1.0 is directly connected, GigabitEthernet2/0
10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
S 10.0.2.0/24 is directly connected, Loopback0
S 10.0.3.0/24 is directly connected, Loopback0
D 10.0.0.0/21 is a summary, 00:00:07, Null0
S 10.0.1.0/24 is directly connected, Loopback0
S 10.0.4.0/24 is directly connected, Loopback0
S 10.0.5.0/24 is directly connected, Loopback0
R1
R1#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback0
100.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 100.0.1.0/30 is directly connected, GigabitEthernet1/0
O IA 100.0.2.0/26 [110/2] via 100.0.1.2, 00:34:54, GigabitEthernet1/0
20.0.0.0/24 is subnetted, 1 subnets
C 20.0.1.0 is directly connected, GigabitEthernet2/0
10.0.0.0/21 is subnetted, 1 subnets
D 10.0.0.0 [90/51456] via 20.0.1.1, 00:00:16, GigabitEthernet2/0
R1#
ちなみに、R1もR4も、auto-summaryの設定はデフォルトのまま、つまり有効であったのだが、
10.0.x.0/24 は 10.0.0.0/8 に集約されていなかった。
どうも、再配送された経路は集約されないみたいだ・・・。
なんでかな・・・。