circuit and packet switching

What is a switch and its function?

A switch is a multi-input, multi-output device, which transfers packets from an input to one or more outputs.

Large networks can be built by interconnecting a number of switches. Hosts are connected to the switch using point-to-point link.

A switch receives packets on one of its links and transmits them on one or more other links. This is known as switching or forwarding.

List the different types of switched networks.

Circuit switched networks Packet switched networks o  Datagram networks

o Virtual-circuit networks Message switched networks

Bring out the differences between circuit and packet switching.

Circuit switching	Packet switching
Source  and  destination  host  are  physically	No such physical connection exists
connected
Switching takes place at the physical layer	Switching takes place at network (datagram) or
	data link layer (VCN)
Resources such as bandwidth, switch buffer &	Resources are allocated on demand
processing time, are allocated in advance.
Resources  remain  allocated  for  the  entire	Resources can be reallocated when idle.
duration of data communication.
There is no delay during data transfer.	Delay exists at each switch during data transfer
Data transferred between the two stations is a	Data is transferred as discrete packets
continuous flow of signal
Example: Telephony	Example: Internet