what is computer network

 Two or more computers connected together is called a network. You can add to their Wire or Wireless to share data.

Talking about Wire Medium, it can be anything from twisted pair cable, Coaxial cable and Fiber Optics Cable. If we talk about Wireless Medium, then it will be one of Radio Wave, Bluetooth, Infrared, Satellite.

A network is a collection of many computers, servers, mainframe, network devices. In which the work of data sharing is generally done. The best example of a network is the Internet. Where millions of people stay connected and share data. What is Networking Devices like Router, Hub, Switch, Modem, all these are used in a network. Whatever I have explained above is called network.

Each computer connected in the network is called Node. Along with data sharing in general, we can share Resource Sharing like Internet, Printer, File Servers. Resource sharing means, when you go to Net cafe and Cyber cafe then you must have seen there many computers are connected with each other. Which we can also call Network.

But there is one or two printers in that cafe. Whenever you print from any of the computers, the print comes out from only one printer. So here with the help of network we are sharing a resource means a printer. This is called Resource Sharing.

Internet is the world's largest network in which we keep sharing something everyday. For example, Image, Video, Contact, song in whats app, all this has become possible with the help of a network. By the way when we use our phone then everyone says network is not available.

This means we are not connected with other mobile and with Tower. This was some information What is Network in Hindi. Now we will tell you about the criteria of Network.

network definition

With these few criteria, we can tell whether the network of the network is perfect or not. That is Performance, Reliability, Security. Know about each one in detail.

1.Performance

We can measure performance in many ways. Special among them is Transmit Time and the second is Response Time. The time it takes for a message to reach from one device to another is called transmit time. The time it takes to respond to a request is called Response Time. Like you did some search in Google and the time it takes to get the result is the Response Time.

Performance also depends on some other factors. How many users are there, what is the Transmission Medium, what is the Hardware and Software. By the way, two Networking Metrics are used to find out the performance Throughput and Delay. We generally need more throughput and less delay. This is what counts for both.

Reliability

It means being dependable. Unless a network is trustworthy, it can never be a good network. Reliability means Accuracy of Delivery. As long as the data reaches the device on which it is being sent without link failure, then it is reliable. Reliability is the time it takes to recover from a link failure.

Security

Only by having security, we can protect the data from Unauthorized Access. Avoid damage to data. It is the job of SECURITY to implement policies to save from data loss. If data is stolen from the network, then it will be said that our data is not secure. It is very important to have Network Security.

History of Network

The network we are talking about was started many years back in 1960 to 1970. The name of that network is ARPANET which we call Advance Research Project Agency Network. Initially, the purpose of the network was to connect terminals and remote job entry stations with the mainframe. But ARPANET had a fundamental element of introducing the concept of resource sharing at that time.

ARPANET was very reliable in that door because it used packet switching technology instead of circuit switching. ARPANET was also used in the Defense Department of America to send secret letters.

In connecting it to different universities of US. Industrialists also started using it. Slowly, we kept on developing it further. Today it has become the world's largest network, which we call the Internet.

Devices used in the network

If there is a network, then all the devices in it are connected to each other, DATA also comes and goes, DATA passes through different computers. To connect two networks together and to connect computers to LAN. For all this we need some network devices like HUB, Repeater, Switch, Router, Modem, Bridge. Know about them from bed.

HUB

Hub is a basic networking devices. This device works in the physical layer. Because of this, it physically connects networking devices together. Generally, in the network where Twisted pair cable is used, this device is used only there.

Without any change, it works to forward a packet to other devices. It transmits to all devices regardless of whether the "data packet" is for the device or not. There are two types of hubs Active HUB and Passive HUB.

switch

Switch also works on Physical Layer like HUB. This device is more intelligent than HUB. The HUB simply forwards the Data Packet but along with the Switch Forwarding it also filters. That's why it is called intelligent.

When the Switch receives the DATA packet. Then it finds the address by filtering it. And forwards the packet to that device. Therefore Switch maintains the CAM (Content Addressable Memory) table. In which the address of the devices remains. CAM is also called Forwarding Table.

Modem

Modem is used by everyone in today's internet world. Whenever we use the Internet at home, only then the DATA reaches our computer from the outside world. But our computer understands only digital data such as binary 0 and 1. And the data in cables goes in the form of analog signal.

MODEM is made up of Modulator and Demodulator. Let me explain with an example, the data in your computer is in digital form. We have to send this DATA to another computer through a cable. For this we have to convert digital DATA to analog.

Modulator does this work. When this analog DATA cable goes to the computer, then it has to convert this analog DATA into digital. Demodulator does this work. It is used in telephone line.

router

By the name of the router itself, you must have come to know that it is related to Route. The job of this device is to control the route and traffic between two networks. It connects two networks with Wire and Wireless medium.

This device works in the network layer of OSI Model. Nowadays Wireless Router is used more. It determines the direction of DATA in the same way as the traffic police works.

bridge

As Router connects two different networks, similarly Bridge connects two sub networks. Which belong to the same network. Let's take an example. You can connect two computer labs and two floors only through a bridge.

Repeater

Repeater is an electronic device. Which helps in increasing the signal strength. You can also call it this, it is such an electronic device that receives the signal and retransmits it. Repeater signal prevents from getting lost. Because of this, DATA reaches far and wide without getting lost.

If in a college the hostel is far away from the college. The college people want that they want to provide internet connection through cable to the hostel and college. Due to the long distance, the data does not reach the receiver properly and the data gets lost.

For this, a repeater will have to be installed between the cable that will be installed between the hostel and the college. There is a limitation in the data transmission distance of every cables. By now you must have known Networking in Hindi. What is network and about network devices. Now you will know the types of network

.Types of Network – Types Of Network

By the way, there are many types of Computer Network. They have been divided according to their size, geographic area and how many computers can live in a network. Starting from a small room, a network can connect computers all over the world.

So let's know how many types of networks are there?

There are generally 3 types of networks LAN, MAN and WAN. Even after leaving these, there are some others like PAN, HAN.

1. Personal Area Network (What is PAN)

Where does PAN go to Personal Area Network. This network is also called PAN. This is a small network which has its limit inside a house. Like in a building, one or more computers reside in PAN. Along with this, telephone, video game and some other devices are connected.

2. What is Home Area Network (HAN)

If some people are using the same network in the same residence, then we can call it Home Area Network. This is also called HAN. In this, there is usually an internet connection from WIRE. Which is connected to a modem. This modem provides both connection means wire and wireless. You can do all these things in this network. WIFI is also Home Area Network.

Sitting in any corner of the house, you can take out the print of the document.

You can also upload and download photos

Along with online video sharing, you can also do video streaming.

There is not much difference between PAN and HAN.

3. Local Area Network (What is LAN)

Local Area Network means LAN. You will find this network everywhere like Office, College, School, Business Organization. This network is used for resource sharing, data storage, document printing. It does not require much hardware to make it, just hub, switch, network adapter, router and Ethernet cable are required.

The smallest LAN can be made up of only two computers. In a LAN, we can connect 1000 computers together. Mostly LAN is used in wire connection. But nowadays it is also being used in wireless. The specialty of this network is its speed, low cost and security. Ethernet cable is used in this.

This network is special for document sharing and printing in an office. What happens in document sharing? There is a central server where all the files are kept. Which an employee can access the file without going there.

If anyone wants to print, he can print using the central printer. This is the advantage of LAN. This is called resource sharing.

If a Local Area Network is wireless, then it is called a wireless LAN.

USP

Its distance is limited in a small geographical area

Used in a home, office and college.

Its ownership is private

This network can be easily created

The data transmission speed of this network is high

4. Metropolitan Area Network (What is MAN)

You can also speak Metropolitan Area Network or MAN. This is a network connecting the whole city. This network keeps the network of all the small and big colleges, schools, government offices connected in a city. MAN is a bigger network than LAN.

MAN covers from 10KM to 100KM. It is used to connect many LANs together to form a large network.

If this type of network is used in a college campus, then it is called campus area network. The best example of this is cable TV Network. MAN is used to connect LAN to LAN. Only a big business organization becomes its own MAN. Through which he can connect his different branches.

USP

Its distance is limited in a large geographical area like town, city.

Its ownership is public and private.

It costs more to install this network than LAN.

The data transmission speed is moderate.

5. Wide Area Network (What is WAN)

The network that comes after LAN and MAN is Wide Area Network. By the way, this is the biggest network which keeps the computers of the whole globe connected. It is also called WAN. Wide area network is called LAN of LANS.

The specialty of this network is that the data rate is low, but it covers more distance. The best example of Wide Area Network is Internet.

There are two types of WAN 1. Enterprise WAN and 2. Global WAN. Computers connected with wide area network mostly use public network such as Telephone line, Leased line and satellites. The biggest WAN is the Internet.

By the way, there are many Wide Area Networks. Like public packet network, Large Corporate network, Military networks, Banking networks, Railway reservation network and finally Airline Reservation network.

The company providing network facility through WAN is called Network Service Provider. These are called the core of the Internet. WAN is said to be the costliest network. Because some such technology is used in this. Such as SONET, Framerelay and ATM.

USP

Large geographical areas like two countries can be connected with each other through this network.

Its ownership is public and private

It is difficult to install and maintain this network.

data transmission speed is slow

Uses of Computer Network

Computer networks are used for the following tasks –

With the help of network, one computer can easily exchange data with another computer.

Communication has become very easy with the use of network. We can talk to a person sitting far away as if he is near us.

With the help of network, we can share data as well as resources.

Networks are also used to share software.