What is a LAN?

A local area network (LAN) is a group of smart devices connected together to create a network within the same location. A home is a good example of LAN consisting of a few computers, tablets, smartphones and IoTs devices over the physical wires and through the Wi-Fi. A LAN can be as small as connecting 2 devices or as large as enerprise network interconnecting thousands of computers, servers and smart devices. A few other examples of LAN include offices, buildings, schools, and corporations.

The characteristic of a LAN is "local", meaning it is limited to a single local location. A purpose of the LAN is to create an isolated private network, and share resources such as the files, printers and wireless access points without tightening security. In 1980s and 1990s, only the larger corporations used the LANs but with wide deployment of Wi-Fi technology, smaller areas such as homes, coffee shops and small offices also deployed LANs.

With cost of DSL and Cable Modem services coming down drastically in the 1990s, the deployment of LANs in consumer homes became commonplace. Also, advancement in wireless technology and introduction of smart devices such as smartphones, tablets and IoT devices contributed toward wide deployment of LANs in consumer homes. A consumer leases a line from an ISP, terminates the line with a router (layer 3 device) and create a LAN by connecting switches (layer 2 device), access points, computers, printers and smart devices to the router.

Companies having multiple locations sometimes create a virtual LANs by interconnecting individual LANs into a single virtual network, called intranet. Virtual LAN is created by using the VPN (Virtual Private Network) technology and the devices within the virtual LAN share resources as if they are local.

What are WAN and MAN?

Wide Area Network (WAN) and Metropolitan Area Network (MAN) are both networks that connects LANs. A MAN is a metropolitan network interconnecting LANs within the same city or metropolitan area. A WAN is also interconnecting many LANs but it spans area greater than a single city. An ISP may deliver a DSL, Cable Modem, or Fiber service through a MAN to a consumer, and the end user will create his own LAN from it. The LANs, MANs and WANs connected together is making up the Internet.