Networking Basic Definitions
A computer network is a communication system for connecting end-systems usually called hosts.
A local area network, LAN, connects computer systems within a few kilometers, usually within a single building. A common technology is Ethernet, which operates at 10Mbps (million bits per second). Computers or workstations connect to the LAN via an interface card.
A wide area network, WAN, connects computers in different cities or countries. A common technology is leased telephone lines operating between 9600 bps and 1.544 Mbps.
Computers in a network use a set of protocols to communicate.