It is necessary to make sure that the protocol is running on every router.
ESR1# show ip ospf neighbors
Router ID Pri State DTime Interface Router IP
--------- --- ----- ----- ------------- ---------
2.2.2.2 128 Full/BDR 00:39 gi1/0/1.10 10.10.10.2
4.4.4.4 128 Full/BDR 00:32 gi1/0/1.40 40.40.40.2
ESR1# show ip ospf
O 40.40.40.0/30 [150/10] dev gi1/0/1.40 [ospf1 1970-01-0
8] (1.1.1.1)
O * 30.30.30.0/30 [150/20] via 40.40.40.2 on gi1/0/1.40 [ospf1 1970-01-0
8] (3.3.3.3)
O 1.1.1.1/32 [150/0] dev lo1 [ospf1 1970-01-0
8] (1.1.1.1)
O * 4.4.4.4/32 [150/10] via 40.40.40.2 on gi1/0/1.40 [ospf1 1970-01-0
8] (4.4.4.4)
O * 20.20.20.0/30 [150/20] via 10.10.10.2 on gi1/0/1.10 [ospf1 22:05:45]
(3.3.3.3)
O 10.10.10.0/30 [150/10] dev gi1/0/1.10 [ospf1 22:05:33]
(1.1.1.1)
O * 3.3.3.3/32 [150/20] multipath [ospf1 22:05:45]
(3.3.3.3)
via 40.40.40.2 on gi1/0/1.40 weight 1
O * 2.2.2.2/32 [150/10] via 10.10.10.2 on gi1/0/1.10 [ospf1 22:05:45]
(2.2.2.2)
mpls
ldp
address-family ipv4
transport-address 1.1.1.1
interface gigabitethernet 1/0/1.10
exit
interface gigabitethernet 1/0/1.40
exit
exit
enable
exit
forwarding interface gigabitethernet 1/0/1.10
forwarding interface gigabitethernet 1/0/1.40
exit