Supernets and subnets use the same underlying technology to accomplish different goals. Supernets seek to expand and simplify complicated network infrastructures by building routing tables that target multiple subnets in a single interface. Subnets, by contrast, break large networks into separate, smaller networks. Knowing when to apply one or the other can help you better organize your network. While an IP address can be virtually any number, subnet masks are defined by which positions, from left to right, represent the “network” number, and which bits, from right to left, represent the “hosts.” All of the 1’s in a subnet mask represent the network number, while all of the 0’s represent the hosts. There can be no break in the network designation. In the above IP address example, if you wanted to label the “192.168” portion as the network and the “.1.1” portion as the host, then you would need a subnet mask of 11111111.11111111.00000000.00000000, or 255.255.0.0 in decimal. This is sometimes also written as 192.168.1.1/16, with the “/16” meaning that 16 bits are reserved for the network address. Supernetting is also used to break beyond the traditional “class” of a given private network number. For example, 192.168.1.0/24 encompasses hosts from 192.168.1.1 to 192.168.1.254. If you need more than 254 hosts, but wish to retain the “192.168.” structure of the addresses, you can implement a /23 subnet, or 255.255.254.0. This changes the address range from 192.168.1.1 to 192.168.2.254, effectively doubling the number of hosts. Writer Bio
