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Is it a right way to supernet/range in OSPF for the following network address?

area 0.0.0.x 10.128.0.0 255.255.255.0

How 10.128.0.0 can have a subnet of 255.255.255.0, e.g. /24?

Is this a right thing to do?

I thought the right subnet should be 255.255.0.0, e.g. /16?

Am I correct on this?

Ron Maupin
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dexterous
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  • Basically, my question is about supernetting , is it correct to supernet the network of 10.128.0.0 with a subnet of 24? Shouldn't that be a subnet of 16? – dexterous Oct 29 '17 at 23:22
  • A supernet is combining two or more networks into a smaller prefix. If you have If you have some larger prefixes, e.g. `/25`, you can combine them to a supernet with any smaller prefix, e.g. `/22`. I think you need to study the excellent answer to [this question](https://networkengineering.stackexchange.com/q/7106/8499). – Ron Maupin Oct 29 '17 at 23:25
  • To avoid confusion, better enable OSPF per interface. – manish ma Oct 30 '17 at 09:35

1 Answers1

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Depending on what your underlying network sizes are, you can aggregate them to a prefix smaller than what you started with. For example, if you have these networks:

  • 10.128.0.0/30
  • 10.128.0.4/30
  • 10.128.0.8/29
  • 10.128.0.16/29
  • 10.128.0.24/29

You can aggregate them into 10.128.0.0/27.

Don't get hung up on the octets, which are simply to make it easier for humans to read. You need to do IP manipulation in binary.

Ron Maupin
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