Packet Switching in computer networks is a method of transferring data to a network in the form of packets. In order to transfer the file fast and efficiently manner over the network and minimize the transmission latency, the data is broken into small pieces of variable length, called Packet. At the destination, all these small parts (packets) have to be reassembled, belonging to the same file. A packet is composed of a payload and various control information. No pre-setup or reservation of resources is needed.