Basically, subnetting enables you to take a number of LAN's and connect them together into one internetwork. It also provides you with the capability to break a large network into subnets that are connected with routers. Segmenting a large network using routers allows you to maximize the bandwidth of the network because the routers keep the traffic on each subnet local; the data isn't broadcast to the entire network.
Each octet in the IP address (although represented as a decimal number) consists of 8 bits. Each bit position has a decimal equivalent. That decimal equivalent isn't realized, however, unless the bit is represented as a 1 (0 bits have no decimal value). The bits on the far left of the octet are referred to as the high-order bits. If you move down to the right end of the octet you are working with the lower-order bits.
