3.6 OSPF [v2 and v3]

here is a mildly interesting situation… as i often use network 0.0.0.0 255.255.255.255 area x, it can prove fatal with summarization…

rene_ospf

router 3’s loopbacks have been configured  using redistributed connected instead of as advertised networks, one of the constraints of the lab… it is also nssa…

Thor(config-router)#do sh run | b router
router ospf 1
log-adjacency-changes
area 3 nssa
summary-address 172.16.0.0 255.255.254.0
redistribute connected subnets
network 3.3.3.0 0.0.0.255 area 0
network 192.168.13.0 0.0.0.255 area 3

if the network statement was the blanket network, the summary address as well as the loopbacks themselves would show up in the routing table of r1, instead of as a single summary below:

Wodan#sh ip route | b Gat
Gateway of last resort is not set

C    192.168.12.0/24 is directly connected, Serial0/0
1.0.0.0/24 is subnetted, 1 subnets
C       1.1.1.0 is directly connected, Loopback0
C    192.168.13.0/24 is directly connected, Serial0/1
2.0.0.0/32 is subnetted, 1 subnets
O IA    2.2.2.2 [110/65] via 192.168.12.2, 00:09:20, Serial0/0
172.16.0.0/23 is subnetted, 1 subnets
O N2    172.16.0.0 [110/20] via 192.168.13.3, 00:09:20, Serial0/1

ie:

Thor(config-router)#no router ospf 1
Thor(config)#
*Mar  1 01:43:22.151: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on Serial0/0 from FULL to DOWN, Neighbor Down: Interface down or detachedrouter ospf 1
Thor(config-router)#netw 0.0.0.0 255.255.255.255 area 3
Thor(config-router)#summary-add 172.16.0.0 255.255.254.0
Thor(config-router)#area 3 nssa
Thor(config-router)#
*Mar  1 01:44:11.899: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on Serial0/0 from LOADING to FULL, Loading Done
Thor(config-router)#redistr connect sub

Wodan#sh ip route | b Ga
Gateway of last resort is not set

C    192.168.12.0/24 is directly connected, Serial0/0
1.0.0.0/24 is subnetted, 1 subnets
C       1.1.1.0 is directly connected, Loopback0
C    192.168.13.0/24 is directly connected, Serial0/1
2.0.0.0/32 is subnetted, 1 subnets
O IA    2.2.2.2 [110/65] via 192.168.12.2, 00:01:39, Serial0/0
3.0.0.0/32 is subnetted, 1 subnets
O       3.3.3.3 [110/65] via 192.168.13.3, 00:01:39, Serial0/1
172.16.0.0/32 is subnetted, 2 subnets
O       172.16.1.3 [110/65] via 192.168.13.3, 00:01:39, Serial0/1
O       172.16.0.3 [110/65] via 192.168.13.3, 00:01:39, Serial0/1