Subnet Number

Subnets are areas of a network based on groups of computers, either at a physical location or some other method of organization. The subnet number goes into the IP address as a specific indicator for where to send packets. Networking systems use something called a subnet mask to determine the part of an IP address that is a subnet number. The subnet number is typically located after the network number in the sequence.

Using subnets helps to minimize the use of full-network IP addresses that are a finite resource on the Web.