Question

Differentiate, with the help of diagrams, between Packet Switching and Circuit Switching.

1. What are the applications of each kind?

2. What are the advantages and disadvantages of each?

3. Give some application names that use Packet Switching and Circuit Switching.

Answer 1

Difference Between Circuit Switching and Packet Switching :

Circuit Switching:

            Its establishes a physical path between the sender and receiver in the network for usage of messaging and telephone conversation(between a caller and the receiver),simply it means that data flows from one node to another node in a network through hardwired connection( copper wire ) setup,this type of switching is called as Circuit Switching.

           Once a connection is established in a telephone conversation, between a caller and the receiver, it remains connected, till the whole conversation is finished and both the caller and receiver hang up their phones. This switching is not appropriate for data transmission because data is transmitted in spurts (stream) and this line remains idle for most of the times ,so the bandwidth is wasted. It is a Connection oriented .

It can be implemented by using two technologies Time Division Switching or Space Division Switching.

Integrated Service Digital Network (ISDN) is a one type application of Circuit switching.

Circuit Switching is implemented at Physical Layer.

Advantages:

• Once the path or circuit is established, data is transmitted without any delay as there is no waiting time at each switch.
• The path/circuit established between sender and receiver provides a guaranteed data rate.

Disadvantages :

• It requires more bandwidth
• Inefficient for bursty traffic.

Packet Switching:

           Packet Switching is connectionless and doesn’t establish any physical connection before the transmission starts. In Packet-switched networks message is transmitted by move data in separate, small blocks called packets . These packets are routed one by one from source to destination. In packet switching, each packet can follow a different route to reach the destination. If Packets arrived at the destination are in out of order ,but they can assembled in order before the destination forward it to the upper layer.

It is always implemented at the Network Layer. It has two approaches Virtual Circuit Approach and Datagram Approach.

Packet Switching is implemented at Network Layer.

Advantages:

• Efficient use of network
• High data transmission is very easy
• It uses digital network and it enables digital data to be directly transmitted toward destination

Disadvantages:

• Packets may arrive in wrong order
• Takes transmission delay
• Requires large amount of RAM to handle amount of data communication in packets

Differences between Packet Switching and Circuit Switching :

Circuit Switching	Packet Switching
In circuit switching there are 3 phases i) Connection Establishment. ii) Connection Released. iii) Data Transfer.	In this switching data transfer can directly takes place .
Purpose: Initially designed for Voice communication.	Purpose:Initially designed for Data Transmission.
Flexibility : Inflexible, because once a path is set all parts of a transmission follows the same path.	Flexibility : Flexible, because a route is created for each packet to travel to the destination.
Delay between data units in circuit switching is uniform.	Delay between data units in packet switching is not uniform.

It is more reliable.	Packet switching is less reliable.
Wastage of resources are more in Circuit Switching	Less wastage of resources as compared to Circuit Switching
Layers: Circuit Switching is implemented at Physical Layer.	Layers:Packet Switching is implemented at Network Layer.
It can be achieved using two technologies, either Time-Division Switching or Space Division Switching.	It has two approaches Virtual Circuit Approach and Datagram Approach.