In circuit switching a message path or data communication path or channel or circuit is dedicated to an entire message block during the process of message transmission fron point A to point B so much so that no other message or user can access that channel during the period in question.The entire bandwidth is dedicated to the said message as it were, and before any data transmission can take place circuit initialisation and setup has to be done to enable or determine the avalaibility of the link as in trying to make a call using the telephon line for voice messaging or even dial-up procedure where you need to establsih that the line is free for use in the first place; and then have the line engaged all through your time of use.All the message travel through the same path and keep the link engaged all the while when the block of message is been relayed or transmitted
But in packet switching the block of data is split into small units with each unit having a sequence number attached to it for orderly identification within a given message block and these different units are usaully sent across the available diffrent links or channels of data transmission from one end to the other end point where they arrvive at different times but have to be assembled together in the correct order at this location via the sequence numbers to get out the original message back without any data degredation occuring as a result of the different paths of transmissions from source to destination.
Also no single data channel is dedicated to any given message block in the course of transmission as many units of different messages can be multiplexed and then get demultiplexed at their deffferent destinations correctly since there are codes to differentiate each unit of message, resulting to no conflict at all. Packet switching splits messages into small units and transmitting them to destination using different paths while at the same time keeping tracks or maintaining an orderliness of the units for proper and correct reassembling of the units to get the original message back.
Packet switching is generally used in Internet data transmmission where we send data without minding if the link is free or not as far as we are connected and the pieces of information that we sent are then split into smaller units and then sent in packets, with each packets switched through different data channel most times and with no loss at the end.
