Computer Network and Its Types - LAN, MAN, WAN - IBPS SBI LIC

Computer Network and Its Types - LAN, MAN, WAN - IBPS SBI LIC

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Computer Network or Networking :-

A computer network consists of two or more computers that are interconnected with each other and share resources such as printers, servers, and hardware and exchange the data in the form of files, facilitating electronic communication. 

Computers on a network can be connected through twisted pair cables, telephone lines, radio waves, satellites or optical fiber cables. 

The first computer network designed was the ‘Advanced Research Projects Agency Network (ARPANET)’ by the United States Department of Defense. Since then, myriads of new computer networking technologies have been designed. 

This tutorial covers three network technologies i.e 
  1. LAN
  2. MAN
  3. WAN 
1. Local Area Network (LAN)
  • It is a system in which computers are interconnected and the geographical spread may be within a building to 1 - 2 kilometer.
  • A number of terminals can be used in the whole building at various places with sharing means.
  • All the terminals are connected to the main computer called server.
Types of LAN :- 

a) Star LAN
  • A number of stations are connected to control station.
  • The station passes information to the central station and then proceed it to the destination station.
  • If one node of the network fails, it does not affect the connectivity.
b) Ring LAN
  • Stations are connected by cables using point-to-point link.
  • Network access is not under control of the central station. Each station can pass data to its adjacent node.
  • Data travels through each node so failure in a single node cause failure of the network.
c) Bus LAN
  • There is no repeater.
  • Stations are common and single communication line.
  • Data is sent in packets and related station picked up by it.
  • Any fault diagnosis is difficult.
2. Metropolitan Area Network (MAN)
  • A metropolitan area network, or MAN, consists of a computer network across an entire city, college campus or small region. 
  • A MAN is larger than a LAN, which is typically limited to a single building or site. 
  • Depending on the configuration, this type of network can cover an area from several miles to tens of miles. 
  • A MAN is often used to connect several LANs together to form a bigger network. 
  • When this type of network is specifically designed for a college campus, it is sometimes referred to as a campus area network, or CAN.
  • Its example is cable TV network.
3. Wide Area Network (WAN)
  • Network spread across countries.
  • The network that brought the world on a single platform.
  • Usually use mainframe oriented systems.
  • Use transmission channels such as co-axial cable or microwave.
Types of WAN  :-

a) Public Networks
  • These networks are owned and run by Telecommunication Authorities.
  • These are made available to an individual subscriber or an organisation, ie, PSTN, PSDN, VAN, ISDN.
b) Public Switched Telephone Networks (PSTN)
  • It is designed for telephone, which requires a modem for data communication.
  • It is used for FAX machine also.
  • Its features—low-speed transmission, analog transmission, less bond width, easy access, cover almost every place.
c) Service Digital Network (PSDN)
  • It is a popular mode for connecting public and private mail system to have electronic mail services with other firms.
  • Its features—high reliable, high-quality communication, cost-effective usage.
d) Value Added Network (VAN)
  • It provides Electronic Data Interchange (EDI) facility.
  • The owner rents out the network to subscribers.
  • Exchange of information like invoices, sale-purchase order, etc, is done.
e) Integrated Services Digital Network (ISDN)
  • l It is used for voice, video and data services.
  • l It uses digital transmission.
  • l It combines both circuit and packet switching.
f) Private Network
  • It provides services at various locations using private or leased circuits by using the technology of its choice.
  • It is mostly used to carry a large volume of data at very high speed transmission.
  • It uses Modem’s multiplexes and other communication devices.
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Difference between LAN, MAN & WAN 
The following table compares LAN, MAN and WAN with respect to various networking parameters.

Parameters
LAN
MAN
WAN
Full Form
Local Area Network
Metropolitan Area Network
Wide Area Network
What is it?
• Systems are close to each other in LAN
• contained in one office or building
• one organization can have several LANs
• Large network which connects different organizations
• Two or more LANs connected
• Located over large geographical area 
Distance
coverage
Limited coverage, about upto 2 miles (or 2500 meters)
Limited coverage, about upto 100 miles(or 200 km)
Unlimited (usually in 1000Km) range, uses a repeater and other connectivity for range extension
Speed of
operation
High, typically 10, 100 and 1000 Mbps
High, typically 100 Mbps
Slow, about 1.5 Mbps (May vary based on wireless technologies used)
Technologies
used for medium
Locally installed, twisted pair, fiber optic cable, wireless (e.g. WLAN, Zigbee)
Locally installed and based on common carrier e.g. twisted pair, fiber optic cable etc.
Locally installed and based on common carrier e.g. twisted pair wires, fiber, coaxial cable, wireless including wireless and cellular network based
Applications
Used mainly by fixed desktop computers and portable computers (e.g. laptops). Now-a-days it is used by smart phones due to emergence of WLAN network
Used mainly by desktop and mini computers.
Can be used by any devices, but desktop devices are mainly using this network type.