From the course: Learning Subnetting

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The need for subnetting

The need for subnetting

From the course: Learning Subnetting

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The need for subnetting

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- [Instructor] In this video let's take a look at the need to do subnetting. After all, our Class A, B, and C networks, they've got default subnet masks. Slash eight, slash 16, slash 24, why mess with that? Why do we need to change our subnet mask? Well, one big reason is that we can potentially be wasting lots and lots of IP addresses. Consider this topology on screen. We've got a couple sites, and these sites are interconnected with a single link. We've got router R1 on one side, and router R2 on the other side. This is a point to point link. There are only two host IP addresses on this entire link. The IP address for R1, and the IP address for R2. And the network we're using here is 192.0.2.0/24, it's a Class C network, and we've assigned these two IP addresses. But if we think about it, we have wasted a whopping 252 IP addresses, and that's because we've suck with the default Class C subnet mask of slash 24. If we had extended that, and we'll see how to do that in this course to a…

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