Networks Big and Small

Networks come in all sizes and shapes. In fact, it is common to categorize networks based on the geographical size they cover, as described in the following paragraphs.

• Local area networks:
  A local area network, or LAN, is a network in which computers are relatively close together, such as within the same office or building.
  Note that the term LAN does not simply that the network is small. A LAN can, in fact, contain hundreds of computers. What makes a network a LAN is that all those computers are located within close proximity to each other. Usually a LAN is contained within a single building, but a LAN can extend to several buildings on a campus provided the buildings are close to each other.
• Wide area networks:
  A wide area network, or WAN, is a network that spans a large geographic territory, such as an entire city, region, or even an entire country. WANs are typically used to connect two or more LANs that are relatively far apart.
• Metropolitan area networks:
  A metropolitan area network, or MAN, is a network that is smaller than a typical WAN but larger than a LAN. Typically, a MAN connects two or more LANs within a same city but are far enough apart that the networks can't be connected using a simple cable or wireless connection.