CIDR Address Selection

I understand the general concept of CIDR and how the prefix and suffix bits work, and I generally understand that you can take an address say:

73.132.68.12/24

There are 24 prefix and 8 suffix bits. The network address corresponding to this would be:

73.132.68.0 as the suffix is all zeros.

Going further, you can break this address down into more subnets by extending the network/prefix a little further. This is where I get a little confused though.

If I extended the prefix by 4, then only the last 4 bits would have to be 0 for the network address of any of the subnets. Does this me开发者_JAVA百科an that I have to use the first 4 bits in the last byte to identify the subnets? Here's what I mean in example...

73.132.68.16 --> subnet 1 with final byte as 0001 0000
73.132.68.32 --> subnet 2 with final byte as 0010 0000
73.132.68.48 --> subnet 3 with final byte as 0011 0000

etc.

Would this be an appropriate way to subnet the address ?

Is there a better way?

Yes, that's how it works in general, in your example you would have networks 73.132.68.0/28, 73.132.68.16/28, etc. The subnets are identified by the whole network prefix (28 bits in your example) so you should not consider only the last byte. Byte boundaries don't hold any special meaning, apart from having common C/B/A class names.