Lets first understand what is Subnetting?
Process of dividing an IP network in to sub divisions is called subnetting. Subnetting divides an IP address in to two parts as the network (or routing prefix) and the rest field (which is used to identify a specific host). CIDR notation is used to write a routing prefix. This notation uses a slash (/) to separate the network starting address and the length of the network prefix (in bits). For example, in IPv4, 192.60.128.0/22 indicates that 22 bits are allocated for the network prefix and the remaining 10 bits are reserved for the host address. In addition, routing prefix can also be represented using the subnet mask. 255.255.252.0 (11111111.11111111.11111100.00000000) is the subnet mask for 192.60.128.0/22. Separating the network portion and the subnet portion of an IP address is done by performing a bitwise AND operation between the IP address and the subnet mask. This would result in identifying the network prefix and the host identifier.
Benefits of Subnetting
1. More efficient use of an IP network address.
2. Ability to organize your resources within a network.
3. Ability to secure your resources by placing them into separate subnetworks
