IGNOU BCA 4th sem Solved Assignment - Differentiate between the packet switching and Circuit Switching.

Differentiate between the packet switching and Circuit Switching.

Ans

Packet Switching :

A digital networking communications method that groups all transmitted data – regardless of content, type, or structure – into suitably sized blocks, called packet.

In packet-switching, the packets are sent towards the destination irrespective of each other. Each packet has to find its own route to the destination. There is no predetermined path; the decision as to which node to hop to in the next step is taken only when a node is reached. Each packet finds its way using the information it carries, such as the source and destination IP addresses.

If a packet switch does not have enough resources, it sends a Connect Reject and the Connection Establishment Fails. Packet switching is a communication method in which packets are routed between nodes over data links shared with other traffic. In each network node, packets are buffered (aka "queued in"), resulting in variable delays. 

Packet switching or "connectionless data transmission":

can be more reliable;
because packets may have to be received over different routes 
and must always be re-assembled into correct sequence. 
overhead is used for routing data units;

Packet Switching	Circuit Switching
Variable rate data stream(packed) over a shared connection	Constant rate data stream(packed) over some dedicated connection
characterized by a fee per unit of information.	characterized by a fee per time unit of connection time, even when no data is transferred
Low reliable , subject to congestion	Highly reliable

·         at start of transmission no need to worry about establishing a route;

·         ability to send data packets over any route means transmission 

·         completion of transmission can sometimes be subject to delays 

Circuit Switching :

Circuit-switched is a type of network in which a physical path is obtained for and dedicated to a single connection between two end-points in the network for the duration of the connection.

Ordinary voice phone service is circuit-switched. The telephone company reserves a specific physical path to the number you are calling for the duration of your call. During that time, no one else can use the physical lines involved. Circuit switching establishes fixed bandwidth circuits/channels between nodes and terminals before the users may communicate.

Circuit switching or "connection-oriented data transmission":

·         path must be decided before data transmission starts;

·         completion of transmission can be faster because less 

·         if the connection breaks so does transmission of data.