A switch is a device which provides bridging functionality with greater efficiency. A switch acts as a multi-port bridge to connect devices or segments in a LAN. The switch has a buffer for each link to which it is connected. When it receives a packet, it stores the packet in the buffer of the receiving link and checks the address to find the outgoing link. If the outgoing link is free, the switch sends the frame to the particular link.

There are two types of switches:

  •  Store and forward switch
  •  Cut – though switch

A store and forward switch stores the frame in the input buffer until the whole packet has arrived.
A cut through switch, forwards the packet to the output buffer as soon as the destination address is received.

Do not confuse switches with routers. The video below explains the difference between switches and routers.