There are three main types of switching used in communication networks: circuit switching, packet switching, and message switching. Circuit switching establishes a dedicated electrical path between two ports or hosts for the duration of a call. Packet switching breaks communication down into small packets that are routed through a network based on destination addresses. Message switching treats each message as an independent unit that is transmitted from node to node without establishing a direct link between sender and receiver.

2.  Switching is a process moving data from one
interface and delivering it through another
interface, selecting the best paths between
machines that stores messages.
 The fundamental purpose of a communication
system is to exchange information between two
or more devices.
 A switched network consists of a service of
interlinked nodes called switches, switches are
hardware and or software device capable of
creating temporary connections b/w to or more
devices linked to a switch but not to each other.

3.  CIRCUIT SWITCHING
 PACKET SWITCHING
 MESSAGE SWITCHING

4.  Circuit switching is the dominant technology
for both voice and data communication.
 Communication via circuit switching in data
communication networks implies that there is
dedicated electrical, communication path
between two ports or hosts.
 The electrical path may be realized by
physical wires or co axial cables or radio or
satellite communication.
 Data transmission using a public switched
telphone network connection is a typical
example of a circuit switched data transfer.

6.  Packet-switched describes the type of network in
which relatively small units of data
called packets are routed through a network
based on the destination address contained
within each packet.
 Breaking communication down into packets
allows the same data path to be shared among
many users in the network.
 This type of communication between sender and
receiver is known as connectionless .
 Most traffic over the Internet uses packet
switching and the Internet is basically a
connectionless network.

8.  A message is a logical unit of information and
can be of any length.
 In message switching, if a station wishes to
send a message to another station, it first
adds the destination address to the message.
 Message switching does not establish a
dedicated path between the two
communicating devices i.e. no direct link is
established between sender and receiver.
 Each message is treated as an independent
unit.

9.  In message switching, each complete
message is then transmitted from device to
device through the
internetwork i.e. message is transmitted
from the source node to intermediate node.
 The actual path taken by the message to its
destination is dynamic as the path is
established as it travels along.
 When the message reaches a node, the
channel on which it came is released for use
by another message.