87-01-45.1 Control of Wide Area Networks

Local area networks (LANs) have become commonplace in most medium and large companies. Now, wide area networks (WANs) have become the next communications frontier. However, WANs are much more complicated than LANs. In most WAN environments, the more devices an individual has to manage, the more time-consuming is the process of monitoring those devices. Complexity also increases very rapidly due to the fact that each new device on the network invariably has to interface with many existing devices. In order to get a further understanding of WANs, it is useful to explore the differences between WANs and LANs. LANs are defined as communications networks in which all components are located within several miles of each other and communicate using high transmission speeds, generally 1M-bps or higher. They are typically used to support interconnection within a building or campus environment. WANs connect system users who are geographically dispersed and connected by means of public telecommunications facilities. WANs provide system users with access to computers for fast interchange of information. Major components of WANs include CPUs, ranging from microcomputers to mainframes, intelligent terminals, modems, and communications controllers. WANs cover distances of about 30 miles, and often connect a group of campuses. WANs are usually static in nature. Changes to them require rerouting telephone lines and installing modems. LANs on the other hand can be quickly reconfigured; communications lines are set up and rerouted more easily and gateways to host computers can be quickly added.