A packet contains the address of the computer that sent it and the computer to which it is sent. Packets Are Not All the Same Size Packet Transmission Seems Instantaneous A packet switching system permits multiple pairs of computers to communicate across a shared network with minimal delay because it divides each conversation into small packets and arranges for the computers that share a network to take turns sending packets. Sharing Is Automatic Because packet switching systems adapt instantly as compters become ready to send data or others finish sending data, each computer receives a fair share of network resources at any given time. Network Hardware Handles Sharing From a computer's point of view obtaining fair access to a shared network is automatic - the network hardware handles all the details. Although many types of devices can connect directly to a computer network, each such device must contain a small computer that handles communications.
All data is transferred across the Internet in packets.
A sender divides a message or document into packets and transfers the packets across the Internet. A receiver reassembles the original message from the packets that arrive. Packets from many machines traverse the Internet at the same time.