Configuring OSPF Interface

Enabling OSPF takes the user to the Router Configuration Mode from which the router related commands are executed. Disabling OSPF terminates the OSPF process.

To enable OSPF, execute the following commands.
Type the following:
- Enter the Global Configuration Mode in ISS1.
```
iS5comm# configure terminal
```
- Enable OSPF globally in the switch ISS1.
```
iS5comm(config)# router ospf
```
- Enable OSPF over the VLAN interface and associate the interface with an OSPF area. VLAN interfaces VLAN1 and VLAN10 are created as a part of the prerequisite configuration.
```
iS5comm(config-router)# network 10.4.0.1 area 0.0.0.0
```
```
iS5comm(config-router)# network 10.10.2.1 area 0.0.0.6
```
```
iS5comm(config-router)# exit
```
Note:
Enabling OSPF over the VLAN interfaces defines the interfaces on which OSPF runs and the area ID for those interfaces.

Note:
When OSPF routing is enabled using the “network” command, an established session is properly mapped with the interface only if the interface administrative status is up. This is because to enable OSPF in an interface, both IP address and interface index are used.

View the configuration details by executing the following show command.

Type the following:

iS5comm# show ip ospf

OSPF Router ID 10.10.2.1

Supports only single TOS(TOS0) route

ABR Type supported is Standard ABR

It is an Area Border Router

Number of Areas in this router is 2

Area is 0.0.0.6

Number of interfaces in this area is 1

SPF algorithm executed 6 times

Area is 0.0.0.0

Number of interfaces in this area is 1

View the configuration details by executing the following show command.

Type the following:

iS5comm# show ip ospf interface

vlan1 is line protocol is up

Internet Address 10.4.0.1, Mask 255.255.0.0, Area 0.0.0.0AS 1, Router ID 10.10.2.1, Network Type BROADCAST, Cost 1

Transmit Delay is 1 sec, State 4, Priority 1 Designated RouterId 10.10.2.1, Interface address 10.4.0.1

Backup Designated RouterId 10.4.0.4, Interface address 10.4.0.4

Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

Hello due in 8 sec

Neighbor Count is 3, Adjacent neighbor count is 3 Adjacent with the neighbor 10.4.0.4

Adjacent with the neighbor 10.4.0.3

Adjacent with the neighbor 10.4.0.2

vlan10 line protocol is up

Internet Address 10.10.2.1, Mask 255.255.255.0, Area0.0.0.6

AS 1, Router ID 10.10.2.1, Network Type BROADCAST, Cost 1

Transmit Delay is 1 sec, State 4, Priority 1 Designated RouterId 10.10.2.1, Interface address

10.10.2.1

Backup Designated RouterId 10.10.1.8, Interface address 10.10.2.8

Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

Hello due in 6 sec

Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with the neighbor 10.10.1.8 OSPF Router ID

10.10.2.1

Execute the “no” form of the command to disable OSPF routing for all defined interfaces and to remove the area ID of the interface.
Type the following:
```
iS5comm(config-router)# no network 10.4.0.1 area 0.0.0.0
```