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New Member

Basic question on how to advertise OSPF routes

When advertising OSPF routes, do I need to do it using the ip address of the interface + reverse mask or should I use the network ? For example:

Imagine I have the following interface:

int s0/0

ip add 152.1.1.6 255.255.255.252

I want to advertise it as OSPF. I do:

router ospf 100

network 152.1.1.6 0.0.0.0 area 0

My question is, what is the implication of doing this as '152.1.1.6 0.0.0.0' or should I do it instead using the network as:

152.1.1.4 0.0.0.3 area 0

3 REPLIES
Hall of Fame Super Bronze

Re: Basic question on how to advertise OSPF routes

Both networks command will advertise the same with the provided interface ip address.

Re: Basic question on how to advertise OSPF routes

Marlon,

The network command under the OSPF process defines which interfaces participate in OSPF and what area does it belong to. Hence, it doesn't matter whether you are using a wild card mask of 0.0.0.0 with the IP of the interface or a less specific WC mask, as long as the interface that you want to run OSPF is covered in the network statement.

However, using a less specific wild card mask contains the risk of including an interface to be assigned to an incorrect area etc. Hence, the better method is to use a wild card mask of 0.0.0.0 with the interface IP to avoid any unexpected mistakes. There's no downside in configuring this way.

Hope this helps!

Sundar

New Member

Re: Basic question on how to advertise OSPF routes

hai

152.1.1.6 is the only addrs advertised , 0.0.0.0 means exactly matches the single ip addrs

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