Switch

Switch

1. In a network, a switch is similar to a hub, in that it provides a central connection between two or more computers on a network, but with some intelligence. (A switch operates on Layer 2 (or above) of the OSI 7 layer model and a hub operates at Layer 1.) Whereas for a hub any message received at the hub is broadcast to all the attached computers, with a switch it is sent only to the destination computer and is not visible to other attached devices. This does not prevent "broadcast" messages from being sent to all attached devices. cf hub and router.

2. An electrical device used to turn current on and off. For example a light switch.

3. To change. For example switch cars would mean to move from one car to another.

4. In software development languages, a switch statement is a control statement which allows one of a set of statements to be selected based on the value of some parameter. In some development languages a switch statement is known by the alternative name of a select statement (but do not confuse this with select in SQL which is not related.)