1.Defining networks?


           Defining Network?


A network consists of two or more computers, lap-tops, fax machines etc that are linked in order to share resources (such as printers and CDs), exchange files, or allow electronic communications. The computers on a network may be linked through cables, telephone lines, radio waves, satellites, or infrared light beams.

Three very common types of networks include:

  • Local Area Network (LAN) 
  • Wide Area Network (WAN)
  • Metropolitan Area Network (MAN)

Local Area Network(LANs)


A Local Area Network (LAN) is a network that is spread in a small area such as a office, school, or factory plant.

Computers connected to a network are broadly categorized as servers or workstations. 

Ex: your computer in your office is in LAN network

Servers are generally not used by humans directly, but rather run continuously to provide “services” to the other computers (and their human users) on the network.

Workstations are called such because they typically do have a human user which interacts with the network through them.

Workstations were traditionally considered a desktop, consisting of a computer, keyboard, display, and mouse, or a laptop, with with integrated keyboard, display, and touchpad.

Servers tend to be more powerful than workstations, although configurations are guided by needs. For example, a group of servers might be located in a secure area, away from humans, and only accessed through the network.

On the other hand, a workstation might not need as much storage or working memory, but might require an expensive display to accommodate the needs of its user. Every computer on a network should be appropriately configured for its use.


Wide Area Network(WANs)


Wide Area Networks (WANs) connect networks in larger geographic areas, such as two states or provinces to the world. 


Using a WAN, offices in London can communicate with places like New Delhi in a matter of seconds, without paying enormous phone bills.

Dedicated transoceanic cabling or satellite uplinks may be used to connect this type of global network.

Two users a half-world apart with workstations equipped with microphones and a webcams might teleconference in real time.

A WAN is complicated. It uses multiplexers, bridges, and routers to connect local and metropolitan networks to global communications networks like the Internet. 


To users, however, a WAN will not appear to be much different than a LAN.

Metropolitan Area Networks (MANs)

A MAN is a network comprising of all computers in one city or whole of university campus. A MAN can be considered as intermediate of LAN & WAN in terms of size.

A MAN (like a WAN) is not generally owned by a single organisation. The MAN, its communications links and equipment are generally owned by either a consortium of users or by a network service provider who sells the service to the users.


Most widely used technologies to develop a MAN (Metropolitan Area Network) network are FDDI (fiber distribution data interface), ATM (Asynchronous Transfer Mode) and SMDS (switched multi megabit data service).

ATM  is the most frequently used of all. ATM  is a digital data transfer technology. 


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