"ip ospf 1 area 0" command necessary?

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Hi ITProTV! I was playing with ospf in the lab and a question came up regarding ospfv2 on traditional IOS. After studying I thought the only requirement for getting this going was to issue the following commands..

R2(config)#router ospf 1
R2(config-router)#router ospf 1
R2(config-router)#network 192.168.104.0 0.0.0.255 area 0
R2(config-router)#network 192.168.105.0 0.0.0.255 area 0

I notice that there is a command you can issue directly on the interface "ip ospf 1 area 0".. See interface running config below.

Now I thought this type of command was only really necessary with osfpfv3, but it would look a little different.. ipv6 ospf <n> area 0. When would I use this "ip ospf 1 area 0" command with ospfv2?

interface GigabitEthernet0/0
ip address 192.168.104.5 255.255.255.0
ip ospf 1 area 0
duplex auto
speed auto
end

Regards,
Adam Tyler

@Adam-Tyler said in "ip ospf 1 area 0" command necessary?:

Now I thought this type of command was only really necessary with osfpfv3, but it would look a little different.. ipv6 ospf <n> area 0. When would I use this "ip ospf 1 area 0" command with ospfv2?

You can do this same configuration with both OSPFv2 and OSPFv3.
There is no real requirement, it's just another way to do it. Now, having said that there is a benefit to configuring it like this, though not for the CCNA exam.

The benefit of configuring OSPF on the interface:

• you can configure OSPF on a single interface instead of globally.
• you also do not have to worry if the networks change...or ip address changes. On the router config, you would have to reconfigure the network statements if your interface IP addresses changed to a different network.

Usually, you'll see something like this not on CCNA but at the CCNP exams...and in real life as networks can and do change on router interfaces for real world reason.

@Adam-Tyler said in "ip ospf 1 area 0" command necessary?:

Now I thought this type of command was only really necessary with osfpfv3, but it would look a little different.. ipv6 ospf <n> area 0. When would I use this "ip ospf 1 area 0" command with ospfv2?

You can do this same configuration with both OSPFv2 and OSPFv3.
There is no real requirement, it's just another way to do it. Now, having said that there is a benefit to configuring it like this, though not for the CCNA exam.

The benefit of configuring OSPF on the interface:

• you can configure OSPF on a single interface instead of globally.
• you also do not have to worry if the networks change...or ip address changes. On the router config, you would have to reconfigure the network statements if your interface IP addresses changed to a different network.

Usually, you'll see something like this not on CCNA but at the CCNP exams...and in real life as networks can and do change on router interfaces for real world reason.