What is LAN,WAN,MAN,PAN?

A Local Area Network (LAN) consists of two or more computers connected together in a building or home using software and hardware. A LAN is contrasted to a wide area network (WAN) such as the Internet, which covers a large geographic area. In a LAN, there is a main computer or server, and remote computers called clients. By creating a LAN in the home or office, computers on the LAN can share files, resources, and if desired, an Internet connection.

A LAN can be one of two types: wired or wireless. A wired LAN requires Ethernet cable to physically connect all computers on the network to a main device called a switch. A wireless LAN uses radio waves to communicate, eliminating the need for wires. Therefore, the hardware used in a LAN should all be of either the wireless or wired type.

A LAN is fairly easy to setup. All Microsoft operating systems since Windows 98 Special Edition (SE) have included built-in networking software. In terms of hardware, each computer requires a network interface card (NIC). A switch is also required. This is a device that resembles an external modem and directs information on the network. If the LAN will be talking to another network, like the Internet, a router is also required. Luckily, one can purchase an external DSL modem with a built-in switch and router, in wireless or wired configurations.

A Wide Area Network (WAN) is a network that spans a large geographical area, the most common example being the Internet. A WAN is contrasted to smaller local area networks (LANs) and metropolitan area networks (MANs). LANs are home or office networks, while a MAN might encompass a campus or service residents of a city, such as in a citywide wireless or WiFi network. The Internet is a public WAN, but there are many ways to create a business model or private WAN. A private WAN is essentially two or more LANs connected to each other. For example, a company with offices in Los Angeles, Texas and New York might have a LAN setup at each office. Through leased telephone lines, all three LANs can communicate with each other, forming a WAN.

Routers are used to direct communications between LANs communicating on a WAN. The router, installed on the leased line, reads the "envelopes" or headers on each packet of data that passes through the WAN, sending it to the proper LAN. When the packet arrives at the LAN, a device called a switch sends the data packet on to the correct machine. Hence, the WAN acts like an interface between LANs for long-distance communication. A WAN that runs on a leased line is a private WAN, as there is no public traffic on the line.

A Metropolitan Area Network (MAN) is a network that interconnects users with computer resources in a geographic area or region larger than that covered by even a large local area network (LAN) but smaller than the area covered by a wide area network (WAN). The term is applied to the interconnection of networks in a city into a single larger network (which may then also offer efficient connection to a wide area network). It is also used to mean the interconnection of several local area networks by bridging them with backbone lines. The latter usage is also sometimes referred to as a campus network.

Examples of metropolitan area networks of various sizes can be found in the metropolitan areas of London, England; Lodz, Poland; and Geneva, Switzerland. Large universities also sometimes use the term to describe their networks. A recent trend is the installation of wireless MANs.

Topology refers to the shape of a network, or the network's layout. How different nodes in a network are connected to each other and how they communicate are determined by the network's topology. Topologies are either physical or logical. Below are diagrams of the five most common network topologies.

A  Personal Area Networks (PAN) is a network that used in very small area, usually occupies a small space, like room. The most famous wireless technology Bluetooth PAN network, and the most popular wired PAN is USB. You may not think of your wireless headset, your printer or your smartphone as elements in a network, but they are definitely talking. Many peripherals are actually computers in their own right. Wi-Fi also serves as a PAN technology, because Wi-Fi is also used in a small area.