Canonicalize CIDR notation

Features Canonicalize CIDR notation

Classless Inter-Domain Routing (CIDR) is a method for allocating IP addresses and for IP routing.
CIDR is a notation for describing blocks of IPv4 addresses and is used heavily in various networking configurations.
IPv4 addresses contain 4 octets, each composed of 8 bits, giving values between 0 and 255.
The decimal value after the slash is the number of bits consisting of the routing prefix.
This in turn can be translated into a netmask, and also designates how many available addresses are in the block.
That is, the IPv4 address portion of the output CIDR block must not contain any 1 (in binary notation) set bits in the host part of the address.For example: 201.105.7.34/24 represents the IPv4 address 201.105.7.34 and its associated routing prefix 201.105.7.0, or equivalently, its subnet mask 255.255.255.0, which has 24 most significant bits of 1.It is also intended to be a teaching tool; useful for both students and teachers.