The term local area network (LAN) describes a network of devices in a limited area (a house, office, building etc.). This type of network is usually capable of achieving high data transfer rate (up to 10 Gbps) at low cost. Examples of this type of network are a small office network inside a single building or your home network.
A typical SOHO (small office/home office) LAN consists of PCs, printers, switches, routers, and cabling that connects all these devices together. The following figure shows a typical LAN:
In the picture above a switch connects two computers. The switch is then connected to a router that provides the Local area network (LAN) with access to the Internet.
Some of the most popular LAN technologies are Ethernet, Token Ring and FDDI. Most of the local area networks use TCP/IP to communicate. LAN usually uses Twisted-pair cabling.
By far, the most popular wired LAN technology is Ethernet. It also defines wiring, signaling, connectors, frame formats, protocol rules, etc. Most modern LANs also support the wireless LAN (WLAN) technology, defined by the IEEE 802.11 standards. WLANs use radio waves instead of wires or cables for links between devices.
The term metropolitan area network is used to describe a network in a single metropolitan area, hence the name. This type of network is usually bigger than a LAN and smaller than a WAN. An example of this type of network would be a network that connects two company offices inside the same city.