OK, I know there are a lot of terms and conditions, so let's just break it down with a real world
scenario.
Although the standard for A and B class network specify eight and 16 bit mask's respectively, it's
common to assign non-standard masks for subnet, resulting in much more limited address spaces.
For example, using 10 dot WSDOT y y zero size 24 results in 256 host company subnets.
Right.
So this is done for scalability and of course, security.
OK, so we're the system administrators in Company X and ready to build.
We have decided to use one nine two one six eight Eckstut acts as a private IP address base for our
company.
If we use the natural mask 255 255 zero zero, that means we use the first 16 bits for network ID.
And we'll have a single network.
So in this case, we can address sixty five thousand five hundred and thirty six devices in this network.
Of course, the first type in the last IP were not allowed to use, so the number of IP addresses actually
sixty five thousand five hundred thirty six minus two, you do the math, but in practice, for ease
of use, it's pretty much used as the power of two.
So you can use an IP address in this network from one nine two one six eight zero to one to one nine
two to one six eight two five 5.2 five four.
But we need to have different networks, one for the managers, one for the developers, one for the
servers, et cetera.
So for the sake of our youth and our sanity, let's use the next eight bits for subnets.
In this case, we have a subnet mask of 255, 255, 255, got 5.0.
Eight bits for subnet and 24 bits for the network I.D. in total, eight bits left for addressing the
devices under the subnets.
So as a result.
We can create 256 subnet.
And address 256 devices for each one.
Now we have 256 address ranges for 256 sub networks.
So the table here shows a few examples of our potential subnetwork.
The red colored blocks are added to the network ID as subnet identifiers, the rest of the eight bits
are used as the host IDs.
In the four block decimal notation, the third block identifies a subnetwork and the last block identifies
the host, so breaking it down, it's much simpler now.
Excellent.
Let's move on.