CIDRmerkintää

CIDRmerkintää, known more formally as Classless Inter-Domain Routing notation, is a method for representing IP addresses and their associated network prefixes. It was developed to overcome the limitations of the older classful IP addressing system, which led to inefficient allocation of IP address space.

In CIDR notation, an IP address is followed by a forward slash and a number. This number, known as the prefix length, indicates the number of bits in the IP address that represent the network portion. For example, in the notation 192.168.1.0/24, the /24 signifies that the first 24 bits of the IP address are part of the network prefix. The remaining bits represent the host portion within that network.

CIDR allows for much more flexible and granular subnetting than classful addressing. Instead of fixed-size network classes (A, B, and C), CIDR enables the creation of networks of virtually any size by adjusting the prefix length. This has been crucial for the efficient routing of internet traffic and managing the growing number of IP addresses. It is used in both IPv4 and IPv6 addressing.