Today, at school I learned about subnetworks. So, let's say I have a network with a mask, I could subnet it into two networks, for example, and, which would both have a mask. But at this point, what's the difference between them being two subnets of or just being two separate networks? Especially if they need routers between them, aren't them just two separate networks?

  • I believe that in this particular instance, subnetting refers to the fact that the addresses are assigned hierarchically, and that the routers outside 10.*.*.* do not need to know internal structure of the 10.*.*.* network. But subnets are pretty fuzzy defined terms, so there isn't always logic in them.
    – Effie
    Dec 20, 2021 at 8:30

1 Answer 1


Today, network and subnetwork are mostly interchangeable. Depending on the context, network might refer to a wider view, an aggregation of multiple subnetworks. Subnetworks is a more precise term for logically distinct networks.

The terms had more distinct meanings when classful networking was still in use before 1993 when CIDR was introduced, but that is long obsolete.

  • So basically, this aggregation could be defined, for example, by the networks being in the same building? If my school has 3 networks, one for each floor, which don't communicate with each other (being,, can they still be considered subnetowks, simply because they're in the same building even tho they don't communicate between them?
    – user81618
    Dec 20, 2021 at 8:37
  • Yes - aggregated over the same building, same city, same security zone, purpose, ... You could have such a "supernet" that actually uses subnets,, ...,
    – Zac67
    Dec 20, 2021 at 8:55
  • 2
    You can also say that every network is a subnetwork of
    – Ron Trunk
    Dec 20, 2021 at 14:05

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