CIDR

Also known as supernetting, CIDR (classless inter-domain routing) is a system that allows one IP address to designate many unique IP addresses. CIDR was created to replace the Class A, B, and C network-based system to slow down the exhaustion of limited IPv4 addresses, and reduce the size of routing tables.

CIDR IP example

A CIDR IP address is quite similar to a standard IP address in its appearance. The only difference is that the CIDR version ends in a forward slash followed by a number. For example:

201.107.4.24/13

That number, called the IP network prefix, designates how many addresses are covered by the CIDR. The number 13 in our example above indicates a capacity for 524,288 addresses.

Computer acronyms, Network terms, Subnet mask