Switching Techniques

 What is Switching?

•                 In Large networks, there can be multiple paths from sender to receiver. The switching technique will decide the best route for data transmission.
•                 Switching technique is used to connect the systems for making one-to-one communication.

Classification of Switching:

•         Circuit Switching.
•         Message Switching.
•         Packet Switching.

 CIRCUIT SWITCHING:

•      Circuit is establish between the two ends.
•      Dedicated path for data to travel from one to other end.
•      Resources are reserved at intermediate switches.
•     The intermediate switches are connected by physical link.

Advantages:

Well defined and dedicated exists for the data to travel.

No waiting time at any switch.

Data is transmitted without any delay.

Data always reaches the other end in order.

DISADVANTAGES:

Channel is blocked for duration of transmission.

Inefficient in terms of utilisation of system resources.

Time required for establishing the circuit is too long.

Message Switching:

•         There is no dedicated path to transfer data from sender to receiver.
•       The message is only forwarded from hop to     hop.
•      When any intermediate switch receives the message,it stores the entire message.
•    The message is stored until sufficient resources become available to transfer it to the next switch.
•   This is called as store and Forward technique.

ADVANTAGES 

• Channel is not blocked.
• More devices can share the channel.
• Helpful in reducing traffic congestion as the message can be stored in the route and forwarded whenever required.

Disadvantages:

• Requires enough storage at every switch to accommodate the entire message during the transmission.
• It is extremely slow due to store and forward technique.

                 

PACKET SWITCHING:

•        Message to be sent is divided into multiple smaller size packets.This process is called PACKETIZATION.

There are two types of packet switching:

• Virtual Circuit Switching 

The first packet informs all intermediate switches.

First packet reserves resources –CPU BANDWIDTH.

2.Datagram Switching

Each packet is treated as separate entity.

It is routed independently through the network  

ADVANTAGES 

•     Cost efficient easier to implement
•      Uses lesser bandwidth
•       It does not take large amount of space 

If packet is lost you can request for new packet.

DISADVANTAGES:

• Unsuitable for applications that can’t afford delays in communication eg:voice calls
• Has high installation costs.
• Require complex protocols for delivery.