Networks   Intranet: The implementation of internet technologies such as TCP/IP and World Wide Web servers for use within   a corporate organization rather than for connection to internet as  a whole.   Local Area Network(LAN): A network in which all the computers occupy a relatively small geographical area,such as department, office, home or building. Most of connections between computers are made via network cables but wireless technology is gaining toehold in same organization. Internetwork: A network that contains two or more LANs by mean of special device such as a bridge or router, Internetwork are often called Internets for short but they shouldn't be confused with Internet the global collection of networks.   Wide Area Network(WAN): This network consists of two or more LANs or Internetworks spaced out over relatively large geographically area, such as a state,country,or the entire world.The networks in WAN typically are connected via high-speed fiber-optic phone lines, microwave dishes, or  satellite link. Network Operating System(NOS): Operating system is a software that runs on NetWare server and provides the various network services for the networks clients.