A subnetwork, or subnet, is a logically visible, distinctly addressed part of a singleInternet Protocol network. The process of subnetting is the division of a computer network into groups of computers that have a common, designated IP address routing prefix.
Subnetting breaks a network into smaller realms that may use existing address space more efficiently, and, when physically separated, may prevent excessive rates of Ethernet packet collision in a larger network. The subnets may be arranged logically in a hierarchical architecture, partitioning the organization's network address space (see also Autonomous System) into a tree-like routing structure.Routers are used to interchange traffic between subnetworks and constitute logical or physical borders between the subnets. They manage traffic between subnets based on the high-order bit sequence (routing prefix) of the addresses.