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Switching Techniques

Switching techniques are used for transmitting data across networks. Different types of switching techniques are employed to provide communication between two computers.
 There are three switching techniques available for digital traffic that are as follows:

1. Circuit Switching :-
    Circuit switching is a technique for implementing telecommunication network that directly connects the sender and the receiver in an unbroken path.
e.g. Telephone switching equipment, establishes a path that connects the caller's telephone to the receiver's telephone by making a physical connection. With this type of switching technique, once a connection is established, a dedicated path exists between both ends until the connection is terminated. 
Routing decision must be made when the circuit is first established, but there are no decisions made after that time. A complete end-to-end path must exist before communication can take place. The main advantage of circuit switching is guaranteed delivery.

2. Message Switching :-
     With message switching, there is no need to establish a dedicated path between two stations. When a station sends a message, the destination address is appended to the message. The message is then transmitted through the network, in its entirely, from source node to destination node.
 Each node receives the entire message, stores it in its entirely on disk and then transmits the message to the next node, if it is not destination node. The type of network is also called store-and-forward network.

3. Packet Switching :-
     Packet switching can be seen as a solution that tries to combine the advantages of message switching and circuit switching and minimize the disadvantage of both. There are two methods of packet switching :
data gram (connection less) and virtual circuit (connection-oriented).
In both packet switching methods, a message is broken into smaller parts, called packets. Each packet is tagged with the appropriate source and destination address. Since, packet have a strictly defined maximum length, they can be stored in main memory instead of disk, therefore access delay and cost are minimize.

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