Conceptual question: Reasoning behind private subnetting scheme?

Question

We have a geographically dispersed WAN. All of the offices have

192.168.n.0/24 local IP address. The point-to-point links between all of our routers are taken from the 192.168.65.0/24 network which has been subnetted into 64 two host subnets 192.168.65.0/30.

Is there a reason the engineer that set up our network chose the

192.168.65.0/24 network to subnet into the site-to-site links? Is this a standard or customary practice, or just his preference? Why not subnet 192.168.254.0 into the site-to-site networks?

I=92m just curious. I have looked all over and have not been able to find any documentation on customary use of private subnets in a situation like this. Is there a best practice defined somewhere?

Thanks, John

Doug McIntyre · Accepted Answer

They just picked it out of thin air. There is no best practice to choosing IP addressing like this, it just happens.

bod43 · Answer

Well err, there is a reason for choosing particular addresses.

If route summarisation is anticipated then it is a decent idea to chose addresses appropriately.

For example:-

192.168.0-63.x can be summarised into a single prefix.

Similarly 128-255.

So if 254 had been chosen then the opportunity to summarise 128-255 would have been lost.

So perhaps the original designer was thinking ahead:)

John H. · Answer

Thanks Bob43.  Route summarization makes since.  That was the conceptI was not seeing.

Conceptual question: Reasoning behind private subnetting scheme?

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