At the end of this lesson-
- 1. You will be able to explain the concept of Computer Network.
- 2. You will be able to explain the objectives of Computer Network.
- 3. You will be able to describe different types of Computer Network.
A computer network is a system in which multiple computers are connected to each other to share information and resources.
Objective of Computer Network:
- Hardware Resource Share
- Software Resource Share
- Information Resource Share
- File Share
- Office Automation
Types of Computer Network:
Network type based on Ownership:
- This network is owned and controlled by a person or private organization.
- This network is not open for all to use. Only registered members can use this network.
- Example: Intranet of an organization.
- This network is not owned and controlled by any person or private organization. But it is run by an organization.
- This network is open for all to use with service charge.
- Example: Internet.
Network type based on Service and Control:
Client Server Network:
A Computer networking model that consists of powerful server computer and some terminal/client computers. A server is a specialized computer that performs all the major operations like security and network management and controls the network resources and provides services to other computers in the network. A client computer receives the requested services from a server.
Client Server Network are two types:
- Centralized Server Network
- Distributed Server Network
Centralized Server Network: Centralized systems are systems that use client/server architecture where one or more client nodes are directly connected to a central server. This is the most commonly used type of system in many organisations where client sends a request to a company server and receives the response.
Distributed Server Network: Mainframe server controls other servers connected to it in the network. Client server computers processes their own data and send latest updates to the mainframe. Some of the processing are done by the mainframe server computer.
Peer to Peer Network:
In this network no server is used for control and each and every node is itself client and server. In this Network, Each and every node can do both request and respond for the services and can shares resources. This type of network supports 25 computers.
Difference between Client-Server and Peer-to-Peer Network:
|S.NO||CLIENT-SERVER NETWORK||PEER-TO-PEER NETWORK|
|1.||In Client-Server Network, Clients and server are differentiated, Specific server and clients are present.||In Peer-to-Peer Network, Clients and server are not differentiated.|
|2.||Client-Server Network focuses on information sharing.||While Peer-to-Peer Network focuses on connectivity.|
|3.||In Client-Server Network, Centralized server is used to store the data.||While in Peer-to-Peer Network, Each peer has its own data.|
|4.||In Client-Server Network, Server respond the services which is request by Client.||While in Peer-to-Peer Network, Each and every node can do both request and respond for the services.|
|5.||Client-Server Network are costlier than Peer-to-Peer Network.||While Peer-to-Peer Network are less costlier than Client-Server Network.|
|6.||Client-Server Network are more stable than Peer-to-Peer Network.||While Peer-to-Peer Network are less stable if number of peer is increase.|
Network type based on Geographical Area Coverage:
There are four types of network based on geographical coverage.
- Personal Area Network(PAN)
- Local Area Network(LAN)
- Metropolitan Area Network(MAN)
- Wide Area Network(WAN)
Personal Area Network(PAN):
Personal Area Network is a type of network arranged by an individual, typically within a range of 10 meters. Personal Area Network is used for connecting personal devices. Personal devices that are used to develop the personal area network are the laptop, mobile phones, media player and play stations etc. Thomas Zimmerman was the first research scientist to bring the idea of the Personal Area Network.
There are two types of Personal Area Network:
Wireless Personal Area Network: Wireless Personal Area Network is developed by simply using wireless technologies such as WiFi, Bluetooth. It is a low range network.
Wired Personal Area Network: Wired Personal Area Network is created by using the USB.
Characteristics of PAN:
- It is mostly personal devices network equipped within a limited area.
- Allows you to handle the interconnection of IT devices at the surrounding of a single user.
- PAN includes mobile devices, tablet, and laptop.
- Appliances use for PAN: cordless mice, keyboards, and Bluetooth systems.
Advantages of PAN:
- PAN networks are relatively secure and safe
- It offers only short-range solution up to ten meters
- Strictly restricted to a small area
Disadvantages of PAN:
- It may establish a bad connection to other networks at the same radio bands.
- Distance limits.
LAN(Local Area Network):
Local Area Network is a group of computers and peripheral devices which are connected to each other in a small area such as school, laboratory, home, and office building. LAN is used for connecting two or more personal computers through a communication medium such as twisted pair, coaxial cable, etc.
Characteristics of LAN:
- It is a private network, so an outside regulatory body never controls it.
- LAN operates at a relatively higher speed compared to other WAN systems.
- There are various kinds of media access control methods like token ring and ethernet.
Advantages of LAN:
- It is less costly as it is built with inexpensive hardware such as hubs, network adapters, and ethernet cables.
- The data is transferred at an extremely faster rate in Local Area Network.
- It will be easy to manage data at only one place, which makes data more secure.
- Computer resources like hard-disks, DVD-ROM, and printers can share local area networks. This significantly reduces the cost of hardware purchases.
- You can use the same software over the network instead of purchasing the licensed software for each client in the network.
- Data of all network users can be stored on a single hard disk of the server computer.
- Local Area Network offers the facility to share a single internet connection among all the LAN users.
Disadvantages of LAN:
- LAN will indeed save cost because of shared computer resources, but the initial cost of installing Local Area Networks is quite high.
- The LAN admin can check personal data files of every LAN user, so it does not offer good privacy.
- Unauthorized users can access critical data of an organization in case LAN admin is not able to secure centralized data repository.
- Local Area Network requires a constant LAN administration as there are issues related to software setup and hardware failures
MAN(Metropolitan Area Network):
A metropolitan area network is a network that covers a larger geographic area by interconnecting a different LAN to form a larger network. In MAN, various LANs are connected to each other through a telephone exchange line. It has a higher range than Local Area Network(LAN). The most widely used protocols in MAN are RS-232, Frame Relay, ATM, ISDN, OC-3, ADSL, etc.
Characteristics of MAN:
- It mostly covers towns and cities in a maximum 50 km range
- Mostly used medium is optical fibers cables
- Data rates adequate for distributed computing applications.
Advantages of MAN:
- It offers fast communication using high-speed carriers, like fiber optic cables.
- It provides excellent support for an extensive size network and greater access to WANs.
- The dual bus in MAN network provides support to transmit data in both directions concurrently.
- A MAN network mostly includes some areas of a city or an entire city.
Disadvantages of MAN:
- You need more cable to establish MAN connection from one place to another.
- In MAN network it is tough to make the system secure from hackers
Uses of Metropolitan Area Network:
- MAN is used in communication between the banks in a city.
- It can be used in an Airline Reservation.
- It can be used in a college within a city.
- It can also be used for communication in the military.
WAN(Wide Area Network):
A Wide Area Network is a network that extends over a large geographical area such as states or countries. A Wide Area Network is quite bigger network than the MAN. A Wide Area Network is not limited to a single location, but it spans over a large geographical area through a telephone line, fibre optic cable or satellite links. The internet is one of the biggest WAN in the world. A Wide Area Network is widely used in the field of Business, government, and education.
Examples of Wide Area Network:
- Mobile Broadband: A 4G network is widely used across a region or country.
- Last mile: A telecom company is used to provide the internet services to the customers in hundreds of cities by connecting their home with fiber.
- Private network: A bank provides a private network that connects the 44 offices. This network is made by using the telephone leased line provided by the telecom company.
Knowledge Based Questions:
- a. What is computer network?
- a. What is PAN/LAN/MAN/WAN?
Comprehension Based Questions:
Multiple Choice Questions: