TCP/IP Guide

IP CIDR Addressing Example

The multiple hierarchical levels of CIDR make the technology seem rather complicated. However, understanding how CIDR works really is not that difficult, assuming you already know how subnetting is done. In particular, if you know how VLSM functions, you basically already know how CIDR works, since they are pretty much the same thing. They differ only in the way that the hierarchical division of networks is accomplished, and in the terminology.

To show how CIDR works better, let's take an example that will illustrate the power of classless addressing: its ability to selectively subdivide a large block of addresses into smaller ones that suit the needs of various organizations. Since address allocation in CIDR typically ...