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Switching

There are two basic kinds of switching in networks: packet switching and circuit switching.

In circuit-switched networks a dedicated end-to-end-connection between the hosts is established and the resources needed along the path are reserved for the duration of the communication. Telephone networks are examples of circuit-switched networks. Time Division Multiplexing (TDM) is used to share a link among all participating connections.

In packet-switched networks like the Internet, packets travel from source over packet-switches to the destination. There are two classes of packet-switched networks: datagram networks and virtual-circuit-networks.

Switches in datagram networks forward packets according to their destination address. They operate in a connectionless manner and no connection-state has to be maintained in the switches. Packets are treated as independent units and may take different routes from source to destination.

Virtual-circuit-networks first establish a path (virtual circuit) between source and destination. Each switch along this path maintains connection-state and all packets of the connection travel along this established path. During connection establishment virtual circuit identifiers are assigned and packets transport these identifiers in the header.

The animation illustrates the differences between these three switching methods. Just chose a method in the drop-down-menu.