Introduction to Computer Network

 In this chapter 

• computer network and its advantages and disadvantage

• Transmission media

• Types of computer Network

• Internet and its use    

 

Computer Network is the interconnection between two or more than two computer. The purpose of computer network is to share the information, data and other resources like hard disk, printer, scanner etc. between computer.

 

The computer on network can be connected through cables, telephone lines , Wi-Fi, radio wave, infrared light beam or satellite each.

Advantages of computer Network

Following are the advantages of computer network

1. It allows us to share data, information ,file and software

2. Resources like hard disk, printer, scanner share

3. it allows easy back up

4. It is easy, cheap and fast

Disadvantage

Following are the disadvantages of computer network 

1. virus may be transmitted if one of computer is infected from virus

2. Data can lost, hacked or stolen

3. Failure of server stops resources being available

The required things for computer

the hardware and software components required for computer Network are as follows:

1) computer system: At least 2 computers are need to form computer network

 

2) Network Interface card(NIC) :we connect Ethernet cable to the NIC of each computers.

 

3) Transmission media is path or channel or road way through which data transfer takes place. It refers to the way data transfer from 1 computer to another.

wired media ===> Guided media

wireless media ===> Unguided media

wired or cable media are of 3 types they are

    a)twisted pair (medium speed)

    b) Coaxial cable(medium speed)

    c) Optical fiber(very speed)

In hilly areas wireless media are more popular.

wire less media are satellites, dish antenna etc

     

 

4)Connecting devices are essential components for connecting computers and transmission media. Some of the popular connecting device are hub, switch, bride, routers and modem.

MODEM stands for modulator and de modulator. Modem is network connecting device that transfer data of one computer to another using transmission transmission media.

 

 HUB is a network connecting device through which we can connect more two computer.

 

Switch is also network connecting device which is similar to hub. switch is more intelligent than hub

 

 

Router is highly intelligent device that connects two or more computer / device together.

5) Network Operating system(NOS)  manages the resources on computer network. eg of NOS   MS windows NT server, MS windows server , Novell Network, UNIX, LINUX etc .

 

Network protocol is a set of rules for communicating while using Computer network.  Network protocol controls and manages how communication between computer on network takes. Some of the popular network protocols are as follows:

 1)TCP/IP(Transmission Control Protocol/ Internet Protocol )

2) FTP(File Transfer Protocol)

3)HTTP (Hyper Text Transfer Protocol)

3) SMTP(Simple Mail Transfer Protocol)

4) POP(Post Office Protocol)

 

Types of Networks 

On the basis of size, distance it cover and type of medium used computer network are classified into 3 types they are :

1) LAN (Local Area Network)

2) MAN (Metropolitan Area Network) 

3) WAN (Wide Area Network)

Local Area Network is type of computer network where computers are interconnected in a small geographical area. LAN connects computer within room, building or short distance with the help wire or wireless medium.

the network of computers in office room, school and cyber etc are the example of LAN

Advantage of LAN

1) It is cheaper to establish

2)It is easier to manage and operate

3)It is security

4)It is not affected environmental factors

5) It is fastest 

Disadvantage of LAN

1) It is in small area

2) It connects less number of computer

3)Its diameter is not more than 3 km

Metropolitan Area Network(MAN) is type of network that connects computer with in a city or in between neighboring cities through wire or wire less devices. combination of 2 or more than 2 LAN form MAN. This type of network is controlled or managed by single organization or group. The network in between banks , hospitals , and their branches with in city or neighboring city are the example of man.

Advantage of MAN

1) it covers large area than LAN

2) It connects more number of computer than LAN

3) it can connect 2 dissimilar network

Disadvantage of MAN

1) It is bit complex to establish

2) It is more expensive that LAN

3) It is not so secure

Wide area Network is a network of computer which connects computer to a larger geographical area such as state , region or country. This computer network used telephone lines, satellite links and other long ranges wireless technology. all facility of LAN and MAN are included in WAN. WAN is slower network than LAN and MAN. Internet is an example of WAN

Advantage of WAN:

• It connects more number computer than LAN and MAN
• It covers large area than LAN and MAN
• we can share data and resources world wide

Disadvantage of WAN

• WAN is slower network than LAN and MAN.

• It is complex to establish , manage and provide security
• It is more expensive than LAN and MAN

Classification based on the model of the network

on the basis of design model , structure and computer hardware and software used computer are classified into 2 types.

1) Client / Server Network

2) Peer to Peer Network

1) Client / Server Network:

it is most popular model of computer network. In network model there is power centralize computer known as server and all the other computer which is known as client or node is connected to the server.

all sharing is from the server computer . Client cannot share. All the control are in the server computer.

this type of network is expensive to setup and required skilled man power is required for set up.  Is useful for the large organization like bank, college , hospital etc.

2) Peer to Peer network

Peer to peer network is a group of interconnected computer that function equally as server and workstation or client. That means every computer are equally power. This type of model is inexpensive and it is easy setup. No expert is need for setup.

Network Topology

The cabling structure or pattern of inter connected computers for sharing data and information is called network topology. In other word it is the physical structure of Network. Network topology are of different types .

Some of the common network topology are as follows:

1) Bus topology 

2) Ring topology

3) Star topology 

1) Bus topology

bus topology is simple type of network topology where all the computer are connected through single communication line called bus or trunk.

Bus topology is simple network topology in which computer are connected through a single line(trunk) or wire in linear for.

Advantage of bus topology

i.                  Easy to setup

ii.                It is cheap

iii.             Requires less wire

iv.             Failure of one computer does not affect network

Disadvantage of bus topology

i.                  It is difficult to detect problem

ii.                It is less flexible

iii.             If trunk is damaged entire network stops working

Ring Topology

Ring topology is simple type of network topology where all the computer are connected in form of ring or circle format.

In ring topology computers are arranged in ring format. In this topology data travels only in one direction either in clockwise or anti clock wise directions.

Advantage of ring topology

i.                  It is easy to setup and maintain

ii.                It is cheap

iii.             All computers are equally important

Disadvantage of ring topology

i.                  Failure of one computer hampers the network

ii.                It is difficult troubleshoot problems

Star Topology

Start topology is type of computer network in which computers are connected through central device called hub or switch

In star topology computer are arranged in star shape.

Advantage of star topology

i.                  Easy to detect problems

ii.                Easy to add and remove devices

iii.             Failure of one computer does not affect network

iv.             Centralized control is possible

Disadvantage

i.                  If hub or central is damage network is affected

ii.                Bit expensive to setup

To learn about Internet and use of internet Click here

Search educational material through web

Search education material through web

There are lots of sites and blog present in web now day. Locating and keeping track of specific site of Internet among millions of websites could be impossible task for individual. The principle method of locating information on the web is search engine,

Search engine is a website through which user can search information in different subects and topic based on Keyword or combination of keyword.

www.google.com, www.yahoo.com, www.msm.com, www.bing.com etc are some popular search engine or website to search require information. Using such website you can search information about about any topic like health, science, education, business and other many more. 

Thus we can search educational material related to you subject through web.

Making search of education material

if you want to search educational material follow the following steps:

• Open any search engine like google or msm or yahoo through web browser
• type the text 'educational material' in the search box
• press enter key or click on search button of the search engine
• It searches for the word 'educational material' in the sites and list all sites where the word appears
• Then close and open the best site among the list of sites and collect necessary information related to the topic
• The text you choose is very important so you need to write the text wisely 

You can now go ahead and look at the individual site and select what you want. Most of the time search results list of 1000s of web pages that matches your words

Additional stuff

Google searching technique