Packet Switching
First proposed for military uses in the early 1960's and implemented on small networks in 1968, packet switching became one of the fundamental networking technologies behind the Internet and most local area networks (LANS). Packet switching is used to optimize the use of the channel capacity available in digital telecommunication networks such as computer networks, to shorten the time it takes for data to pass across the network, and to increase robustness of communication. Packet switching involves packaging data in specially formatted units (called packets) that are typically routed from source to destination using network switches and routers. Each packet contains address information that identifies the sending computer and intended recipient. Using these addresses, network switches and routers determine how best to transfer the packet between hops on the path to its destination. The University of Wisconsin created Domain Name System (DNS). This allowed packets to be directed to a domain name, which would be translated by the server database into the corresponding IP number. This made it much easier for people to access other servers, because they no longer had to remember numbers. The advantages of Packet Switching Under a traditional central system, all information had to be channeled through one source, processed, and sent off somewhere else. More efficient use of overall network bandwidth due to flexibility in routing the smaller packets over shared links. Packet switching networks are often cheaper to build as less equipment is needed as they are sharing. Packet-switching allowed for another method; information could first be sent to one place, and if that site was not working or processing too slowly, could be re-routed somewhere else. This concept, called dynamic re-routing, would allow all hosts to be `equal.' With every computer having the same routing abilities, an enemy would have to destroy nearly all computers on the network to be sure that communication lines were dead. Some disadvantages of packet switching There are Longer delays in receiving messages due to the time required to package and route packets. For many applications, delays are not long enough to be significant, but for high-performance applications like real-time video, additional data compression is often required to achieve the required performance levels. Another negative is that there is potential for network security risks due to the use of shared physical links. Protocols and other related elements on packet switching networks must be designed with the appropriate security precautions. |
"packet switching" is a rapid store-and-forward design.
When a node receives a packet it stores it, determines the best route to its destination, and sends it to the next node on that path. If there was a problem with a node (or if it had been destroyed) packets would simply be routed around it. |