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
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.