switch

In telecommunications, it is a network device that selects a path or circuit for sending a unit of data to its next destination. A switch may also include the function of the router, a device or program that determines the route (and specifically, what adjacent network point) the data should be sent to. In general, a switch is a simpler and faster mechanism than a router, which requires knowledge about the network and how to determine the route.

On larger networks, the trip from one switch point to another in the network is called a "hop." The time a switch takes to figure out where to forward a data unit is called its "latency." The price paid for having the flexibility that switches provide in a network is this latency. Switches are found at the backbone and gateway levels of a network, where one network connects with another, and at the subnetwork level, where data is being forwarded close to its destination or origin.

A switch is not always required in a network. Many local area networks (LANs) are organized as rings (or buses) in which all destinations inspect each message and read only those intended for that destination.