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Engineering a new LAN IP Structure

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Last Modified: 2012-05-11
Hi All,

I am looking at redesigning our private LAN ip structure. We have 26 sites and the subnets are arranged as We have from 192.168.0.X - 192.168.26.X subnets.

We have approx. 100 - 150 devices on each subnet. I was thinking of introducing a CLASS A network.

So The reason? I can use the second octet as a SITE ID, Third Octet as a CATEGORY ID (eg, servers, wireless, laptops, printers etc etc) and the fourth octet is range 1 - 254 for the devices themselves.

Now I like this as a clear identifier of subnets, eg, a wireless device isnt working on, I know this is site Silicon Valley(151), Wireless Device (60).

However, I am concerned that CLASS A is too large for only 150 devices or so in each subnet, is it overkill? What are the downsides of this in a technical level? Should I pursue a CLASS B instead? I am assuming that over the next 3 years we will grow by double, in which CLASS C will not be a viable subnet range.
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We split down by category, but not at the level you are talking.. At the subnet mask you are talking the subnets would be huge...

How about this?

10.Global Region.SiteVlans.Device?

So for example;

Split world or country into 8 chunks (a /11 mask) - regions a-h or whatever you want to call them

So sites in Region A would exist between and, B would be in to

each site would become a /21 mask which would give you 8 .24 vlans on the site

So site A in region A would to

Within Site A you would have your 8 /224 vlans for your device types


I don't see any issue with this idea at all, they are after all just numbers available to use for whatever you need.


Well someone said that I shouldn't do it with class A because if I need to VLAN a segment, I need to use an entire different IP scheme, either 172.16.x.x or 192.168.x.x.

Also, he was concerned that Class A would permit more chatter on the network, though what difference does CLASS A and B have to do with chatter if there are only 150 or so devices on the subnet anyways.

I mean, you need to reach approx. 500 devices before you think of segmenting right?
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Thanks. Obviously I need to use /16. Not sure why I thought /8 was the best solution, its obviously not.

Thanks guys.
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