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Rather than send a continuous stream of data that hogs resources and could easily be broken or lost, information sent by Internet computers involves packets, a packet is a unit of information and on average is about 200 bytes. Every Web page that you receive comes in a series of packets, every E-mail that you send or receive leaves or arrives in a set of packets. Each packet
Packet switching is the process by which a carrier breaks up the data into these units or packets. The packets carry the data in the protocols that the internet uses (TCP/IP). Each packet is numbered and contains a header with the information necessary for routing the packet from origin to destination, i.e. the source of origin and destination address how many packets that information has been broken into. They are then passed on to the Packet Switching Exchange (PSE). The PSE inspects each packet and information so that it can reunite it with other related packets. This allows packets from many different locations to co-exist on the same line.
Each packet is sent to its destination by the best route available. The packets might all take the same route or all different routes. This makes the network more efficient as it can balance the load accross various pieces of equipment, so that if one piece of equipment in the network has a problem the packets can be routed around it, ensuring delivery of the entire message.
Packets are accepted onto the network on a first-come, first-serve basis. However, if the network becomes overloaded, packets can be delayed or discarded (dropped).
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