This article is about message switching which is a type of switching which i discussed in previous to previous article Switching.In this article we will discuss about message switching.
A message is logical unit of information which can be of any length.
In message switching a message is tranmitted by intermediate channel & use store and forwarded technique.There is no need to dedicated path or establishment of connection in advance.Hence no wastage of time in connection establishment.Message are routed independently.In this switching route of same message can be different.
When the sender has block og data to be sent it is stored in the first switching office i,e router and then forwarded later,one hope at a time .Each block is recieved it entirely ,if any error then retransmit it.
Eg.The first electromagnetic communication uses msg switching as telegram.
The message is punched on tape(off-line) at sending office,and then read in and transmitted over a communication line to the next office along the way,where it was punched out on paper tape.
1. No wastage of time in connection establishment.
2. Channel are used only when message are tranmitted.
1. As there is no limit of length of the message hence there must be a buffer of an infinite size with intermediate machine for storing message.
2. Message is delayed at each of the intermediate node in recieving & queuing the message.
3. Poor security.
Friends we will discuss switching type packet switching in next article.