A Local Area Network (LAN) provides a quick, short link between network devices. Most homes and offices have a LAN which allows personal computers and workstations to easily share data between one another at a high rate of transfer. A LAN also enables users to access other devices, such as printers, modems, or local servers. They are privately owned and managed and provide service to relatively small geographical areas. A LAN can serve as few as one user or as many as thousands. Since a LAN covers a small area, noise and error are minimized.
Both a Metropolitan Area Network (MAN) and Wide Area Network (WAN) provide network communications over larger geographical regions. The primary difference between the two lies within the size of the regions being served.
A Metropolitan Area Network is a class of network which serves a large geographical area between 5 to 50 kilometers in range. This geographical area can include several buildings, such as a college campus, sometimes referred to as a campus network, or an area as large as a city (metropolitan area).
These networks are larger than a LAN, but smaller than a WAN, generally providing communications via fiber optic cable, and mostly works within Layer 2, or the data link layer, of the OSI model. Usually, a MAN does not belong to any particular organization, but rather a consortium of users or a single network provider which takes charge of the service, owns its hardware and other equipment, and sells access to the network to end users. In this regard, levels of service must be discussed and agreed upon between each user and the MAN provider.
A Wide Area Network provides coverage far greater than a MAN is capable of providing. A WAN connects LANs and MAns, with an example of a WAN being the Internet. While a WAN, which operates similarly to a MAN, can span the globe, a MAN is only capable of spanning an area between 5 to 50 kilometers in range.