December 06, 2013

Lab 04: OSPF Route Summarization

Configure OSPF in the network. After the configuration, AREA 0 network (10.0.0.0/24) is seen on R7.

R7#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

     38.0.0.0/30 is subnetted, 1 subnets
O E2    38.0.0.0 [110/2000] via 37.0.0.1, 00:05:54, Ethernet2/0
     37.0.0.0/30 is subnetted, 1 subnets
C       37.0.0.0 is directly connected, Ethernet2/0
     10.0.0.0/24 is subnetted, 1 subnets
O IA    10.0.0.0 [110/20] via 37.0.0.1, 00:00:01, Ethernet2/0
     192.168.1.0/32 is subnetted, 1 subnets
O E2    192.168.1.1 [110/2000] via 37.0.0.1, 00:01:02, Ethernet2/0
     192.168.2.0/32 is subnetted, 1 subnets
O E2    192.168.2.1 [110/2000] via 37.0.0.1, 00:01:02, Ethernet2/0
     192.168.3.0/32 is subnetted, 1 subnets
O E2    192.168.3.1 [110/2000] via 37.0.0.1, 00:01:00, Ethernet2/0

Let's summarize AREA 0 network as 10.0.0.0/8 on R3:

router ospf 1
 area 0 range 10.0.0.0 255.0.0.0

R7's routing table after summarization:

R7#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

     38.0.0.0/30 is subnetted, 1 subnets
O E2    38.0.0.0 [110/2000] via 37.0.0.1, 00:01:16, Ethernet2/0
     37.0.0.0/30 is subnetted, 1 subnets
C       37.0.0.0 is directly connected, Ethernet2/0
O IA 10.0.0.0/8 [110/20] via 37.0.0.1, 00:01:16, Ethernet2/0
     192.168.1.0/32 is subnetted, 1 subnets
O E2    192.168.1.1 [110/2000] via 37.0.0.1, 00:00:08, Ethernet2/0
     192.168.2.0/32 is subnetted, 1 subnets
O E2    192.168.2.1 [110/2000] via 37.0.0.1, 00:00:08, Ethernet2/0
     192.168.3.0/32 is subnetted, 1 subnets
O E2    192.168.3.1 [110/2000] via 37.0.0.1, 00:00:09, Ethernet2/0

Also we can summarize external routes coming from RIP on R3:

router ospf 1
 summary-address 192.168.0.0 255.255.0.0

R7's routing table after the summarization:

R7#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

     38.0.0.0/30 is subnetted, 1 subnets
O E2    38.0.0.0 [110/2000] via 37.0.0.1, 00:02:45, Ethernet2/0
     37.0.0.0/30 is subnetted, 1 subnets
C       37.0.0.0 is directly connected, Ethernet2/0
O IA 10.0.0.0/8 [110/20] via 37.0.0.1, 00:02:50, Ethernet2/0
O E2 192.168.0.0/16 [110/2000] via 37.0.0.1, 00:01:22, Ethernet2/0

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