OcNOS-SP : Layer 3 Guide : Layer 3 Unicast Configuration Guide : OSPFv2 : Enable OSPF on an Interface
Enable OSPF on an Interface
The diagram shows the minimum configuration required to enable OSPF on an interface. R1 and R2 are two routers in Area 0 connecting to network 10.10.10.0/24.
Note: Configure one interface so that it belongs to only one area. It is possible, however, to configure different interfaces on a router to belong to different areas.
Topology
Figure 8-64: Basic OSPF Topology
R1
 
#configure terminal
Enter configure mode
(config)#router ospf 100
Configure the routing process, and specify the Process ID (100). The Process ID should be a unique positive integer identifying the routing process.
(config-router)#network 10.10.10.0/24 area 0
Define the interface (10.10.10.0/24) on which OSPF runs, and associate the area ID (0) with the interface (area ID 0 specifies the backbone area).
(config-router)#commit
Commit the candidate configuration to the running configuration.
R2
 
#configure terminal
Enter configure mode
(config)#router ospf 200
Configure the routing process, and specify the Process ID (200). The Process ID should be a unique positive integer identifying the routing process.
(config-router)#network 10.10.10.0/24 area 0
Define the interface (10.10.10.0/24) on which OSPF runs, and associate the area ID (0) with the interface.
(config-router)#commit
Commit the candidate configuration to the running configuration.
Validation
R1
#show ip ospf
Routing Process "ospf 100" with ID 10.12.26.88
Process uptime is 1 minute
Process bound to VRF default
Conforms to RFC2328, and RFC1583 Compatibility flag is disabled
Supports only single TOS(TOS0) routes
Supports opaque LSA
Supports Graceful Restart
SPF schedule delay initial 0 secs 500 msecs
SPF schedule delay min 0 secs 500 msecs
SPF schedule delay max 50 secs 0 msecs
Refresh timer 10 secs
Number of incomming current DD exchange neighbors 0/64
Number of outgoing current DD exchange neighbors 0/64
Initial LSA throttle delay 0 secs 0 msecs
Minimum hold time for LSA throttle 5 secs 0 msecs
Maximum wait time for LSA throttle 5 secs 0 msecs
Minimum LSA arrival 1 secs 0 msecs
Number of external LSA 0. Checksum 0x000000
Number of opaque AS LSA 0. Checksum 0x000000
Number of non-default external LSA 0
External LSA database is unlimited.
Number of LSA originated 4
Number of LSA received 4
Number of areas attached to this router: 1
Area 0.0.0.0 (BACKBONE)
Number of interfaces in this area is 1(1)
Number of fully adjacent neighbors in this area is 1
Area has no authentication
SPF algorithm last executed 00:00:08.102 ago
SPF algorithm executed 3 times
Number of LSA 7. Checksum 0x0312b5
Dste Staus: Disabled
 
#show ip ospf interface
eth2 is up, line protocol is up
Internet Address 10.10.10.10/24, Area 0.0.0.0, MTU 1500
Process ID 100, VRF (default), Router ID 10.12.26.88, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State DR, Priority 1, TE Metric 1
Designated Router (ID) 10.12.26.88, Interface Address 10.10.10.10
Backup Designated Router (ID) 10.12.26.89, Interface Address 10.10.10.11
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:11
Neighbor Count is 1, Adjacent neighbor count is 1
Suppress hello for 0 neighbor(s)
Hello received 13 sent 19, DD received 3 sent 4
LS-Req received 1 sent 1, LS-Upd received 3 sent 5
LS-Ack received 3 sent 3, Discarded 0
No authentication
 
 
#show ip ospf neighbor
 
Total number of full neighbors: 1
OSPF process 100 VRF(default):
Neighbor ID Pri State Dead Time Address Interface Instance ID
10.12.26.89 1 Full/Backup 00:00:39 10.10.10.11 eth2 0
 
 
#show ip ospf route
 
OSPF process 100:
Codes: C - connected, D - Discard, 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
 
C 10.10.10.0/24 [1] is directly connected, eth2, Area 0.0.0.0
R2
#show ip ospf
Routing Process "ospf 200" with ID 10.12.26.89
Process uptime is 1 minute
Process bound to VRF default
Conforms to RFC2328, and RFC1583 Compatibility flag is disabled
Supports only single TOS(TOS0) routes
Supports opaque LSA
Supports Graceful Restart
SPF schedule delay initial 0 secs 500 msecs
SPF schedule delay min 0 secs 500 msecs
SPF schedule delay max 50 secs 0 msecs
Refresh timer 10 secs
Number of incomming current DD exchange neighbors 0/64
Number of outgoing current DD exchange neighbors 0/64
Initial LSA throttle delay 0 secs 0 msecs
Minimum hold time for LSA throttle 5 secs 0 msecs
Maximum wait time for LSA throttle 5 secs 0 msecs
Minimum LSA arrival 1 secs 0 msecs
Number of external LSA 0. Checksum 0x000000
Number of opaque AS LSA 0. Checksum 0x000000
Number of non-default external LSA 0
External LSA database is unlimited.
Number of LSA originated 3
Number of LSA received 5
Number of areas attached to this router: 1
Area 0.0.0.0 (BACKBONE)
Number of interfaces in this area is 1(1)
Number of fully adjacent neighbors in this area is 1
Area has no authentication
SPF algorithm last executed 00:00:45.638 ago
SPF algorithm executed 4 times
Number of LSA 7. Checksum 0x0312b5
Dste Staus: Disabled
 
#show ip ospf interface
eth1 is up, line protocol is up
Internet Address 10.10.10.11/24, Area 0.0.0.0, MTU 1500
Process ID 200, VRF (default), Router ID 10.12.26.89, Network Type BROADCAST, Cost: 1
Transmit Delay is 1 sec, State Backup, Priority 1, TE Metric 1
Designated Router (ID) 10.12.26.88, Interface Address 10.10.10.10
Backup Designated Router (ID) 10.12.26.89, Interface Address 10.10.10.11
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:06
Neighbor Count is 1, Adjacent neighbor count is 1
Suppress hello for 0 neighbor(s)
Hello received 30 sent 31, DD received 4 sent 3
LS-Req received 1 sent 1, LS-Upd received 5 sent 3
LS-Ack received 2 sent 3, Discarded 0
No authentication
 
 
#show ip ospf neighbor
 
Total number of full neighbors: 1
OSPF process 200 VRF(default):
Neighbor ID Pri State Dead Time Address Interface Instance ID
10.12.26.88 1 Full/DR 00:00:33 10.10.10.10 eth1 0
 
#show ip ospf route
 
OSPF process 200:
Codes: C - connected, D - Discard, 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
 
C 10.10.10.0/24 [1] is directly connected, eth1, Area 0.0.0.0
Last modified date: 10/16/2023