What is Computer Network?

The biggest success in technology and communication in the last 20 years has been the development and advancement of Computer Network. From emailing a friend, to online bill payment, downloading data from the Internet, e-commerce, and networking has greatly reduced our world and forever changed the way we communicate.

Computer Network provides key features that have made our lives easy and comfortable, be it sending an email, withdrawing money from an ATM machine, online railway or airline reservations, or sharing audio and video files. Apart from these, the most widely used feature is the print command which is sent from the computer to receive printouts from a printer connected to another computer.

A computer network is a network that connects different computers to each other and handles large amounts of data.

Computer Network – An Overview

Many interconnected devices form a network for reliable communication / data transfer. A network may include a computer, a fax machine, a printer, a camera, a cellphone, etc.

A collection of interconnected computers is called a computer network because two computers or devices are able to exchange information with each other by following a protocol (set of rules).

A computer network is a collection of interconnected computers and other devices to share data and other resources (hardware and software resources).

Advantages of computer network:

Let us now discuss why networks are necessary. Are there any advantages to networked computers over standalone machines? Yes, network systems are better. A network uses a distributed processing system in which a task is divided between several devices that are interconnected with each other.

Therefore, instead of a single computer being responsible for completing the entire task, all the interconnected computers are responsible for completing the TE task assigned to them. This leads to better performance with higher processing speed.

There are several advantages of Computer Network which are given below:

1. Resource Sharing:

The primary use of a network is to share between users program / application, data and peripheral devices connected to the network program, irrespective of their physical location. You may have noticed in your network computer labs that when a print command is given on one computer, the document printed by the printer is connected to another system.

This allows the printing of documents by multiple users and, therefore, the printer is shared by many users across the network. Other resources such as hard disks, DVD drives, scanners, etc. can also be shared across computer networks. For example, sharing databases, audio and video files, antivirus software, application software, printers and scanners, etc.

2. Better Communication:

A computer network enables fast, reliable and secure communication between users. This saves time and provides easier ways of communication. For example, in an organization, managers work in different places to create financial reports. When working on a network, any changes made by a manager to his computer can easily be seen by other managers and employees.

Thus, a network allows managers to easily update information. This increases their efficiency and allows them to complete their work quickly.

3. Reduced Communication Cost:

Sharing of resources also reduces the communication cost. Using public networks, we can send large amounts of data at low cost. Internet and mobile networks are playing a very important role in sending and receiving text, image, audio and video data at low cost.

4. Reliability of Data:

Reliability means backing up data, that is, data can be copied and stored on multiple computers. In a networked system, all computers are connected to each other. Thus, the information or message shared by each device is stored at their respective workstation (computer).

If, for some reason (hardware crash, etc.), the data becomes corrupted and, thus, unavailable on a computer, a copy of the same data can be accessed from another workstation for future use. This leads to smooth functioning and further processing without disruption.

5. Central Storage of data:

Files can be stored on a central node (file server) that can be shared and made available to each and every user in an organization. With centralized processing, data is stored and retrieved from a single central location. Thus, there is no duplication of data and almost no data redundancy.

Types of Computer Network

1. Personal Area Network (PAN):

PANs are small networks that are used to establish communication between computers and other handheld devices in proximity of up to 10 meters using wired USB connectivity or wireless systems such as Bluetooth or infrared.

PAN is used to transfer files including emails, digital photos, audio and video etc. to computers, laptops, mobiles and other IT-enabled devices. Bluetooth technology implements PAN. PANs may include wireless computer keyboard and mouse, Bluetooth enabled headphones, wireless printer and TV remote.

2. Local Area Network (LAN)

A LAN is a privately owned computer network that covers a small geographic area (small physical area), such as a home, office, or building such as a school. It can cover an area spanning a few meters to a radius of a few kilometers. Sometimes, a LAN can span a cluster of nearby buildings. In addition to operating in a limited space, a LAN is owned, controlled, and managed by an individual or institution.

A LAN can be established using wired media (UTP cable, coaxial cable, etc.) or wireless media (infrared, radiowave). If a LAN is set using unaged media, it is known as a WLAN (wireless LAN). The main purpose of LAN is to share resources. LAN users can share data, programs, printers, disks, modems and more.

3. Metropolitan Area Network (MAN)

MAN is larger than a LAN and can cover a city and its surrounding areas. A Metropolitan Area Network usually connects multiple LANs and different computers. It also shares computing resources between users. All types of communication mediums (Guided and Guided Medium) are used to set the MAN. A MAN is usually owned and operated by a governmental body such as an entity. A good example of a MAN is the Mutual Office of a Multinational Company (MNC) (MNC) or cable television network available throughout the city.

4. Wide Area Network (WAN)

WAN is a telecommunications network. This type of network is spread over a large geographical area across countries and continents. WANs are commonly used to connect many other types of networks such as LANS, MANS, etc. They facilitate fast and efficient exchange of information at a fast speed and low cost. A WAN uses common carriers such as satellite systems, telephone lines, etc.

The WAN can cover an area with a circumference of hundreds of kilometers. A network of ATMs, banks, government offices, offices of international organizations, etc. covering a country, continent or several continents are examples of WAN.

All types of communication mediums (directed and unanswered) are used to establish a WAN. The best known example of a WAN is the Internet.

Terminology of Computer Network:

1. Nodes (workstations): The term Nodes refers to computers that are connected to a network and want to share resources.

2. Server: a computer that facilitates the sharing of data, software and hardware resources

3. Network Interface Unit (MAC address):

A network interface unit is an interpreter (translator) that helps establish communication between the server and the client.

4. IP Address: Each machine in the TCP bar IP network has a unique identification number called an IP address.

5. Domain Name: It is a way of identifying and locating computers connected to the Internet, it should be unique. 

Architecture of Computer Network:

A network consists of several components along with their functionality that contribute to its smooth operation. To build a network, a lot of hardware equipment is required which is described as follows:

1. Sender: A device or a computer that sends data.

2. Receiver: A device or a computer that receives data.

3. Message: The message is the information to be transmitted. It can be text, image, audio or video.

4. Transmission Medium: A transmission medium is a physical route through which data flows from sender to receiver. A cable or wire or radio waves can be a medium.

5. Protocols: A set of rules that govern data transmission. It represents the communication methods that are followed by the sending and receiving devices.

Network Devices

Network devices are also called communication devices and they constitute a data communication network. In addition to transmission media, many other devices are required to build computer networks. Some of these devices are:

Network Interface Card (NIC)

Any computer that must be connected to a network must have a Network Interface Card (NIC). Nowadays, most PCs and laptops are equipped with integrated NICs on their motherboards. A computer communicates with other computers on a network with the help of only one NIC. NIC works with MAC address, which we will discuss in later topics.

NIC (Network Interface Card) or LAN Card or Network Interface Unit (NIU) enables connecting to the network using a computer port. WLAN (wireless-LAN) cards are also becoming popular for connecting PCs or laptops to wireless networks.

 A Network Interface Card is a device that enables computers to connect to and communicate with networks.

Hub:

Hub is a connecting device (network devices) that connects multiple computers together to form a local area network (LAN). Hubs create a type of network of broadcasts and do not manage traffic on the network channel. The signal entering from any port of the hub is transmitted to all other ports.

A hub has ports into which cables are inserted from the personal computer’s NIC. In this way, the NIC of each computer is connected to a hub and therefore, all computers are connected together. Whenever a computer has to send some information to some other computers, the information is sent to the hub by the NIC.

The hub then sends this information back to other computers connected to it. The computer that needs the information receives and accepts this information. Other computers in the network only deny this information. Nowadays, switches are used in place of hubs.

Switch:

A switching hub is a network device that is used to interconnect a computer or device to a network. It filters data packets in a network. It is also a multi-port device. A switch is an intelligent hub. It looks exactly like a hub and has the same function: connecting multiple computers / devices in a network.

But the difference between the two is the way they transmit the received information. Instead of transmitting the received information, as opposed to a hub, instead of transmitting the received information to each device, a switch only sends information to the computers by which the information is sought.

Switch remembers all devices connected. This makes the switch more efficient than a hub.

Unlike the hub, a switch only transmits data / signals to a specified node, rather than transmitting signals through the entire network. The switch is faster and more efficient than the hub due to its good traffic management capability.

 Switch is a network device that is an intelligent device that connects multiple nodes to form a network and redirects the received information to only the intended node (workstation).

Repeater:

A repeater is a network device that retrieves received signals and transfers back to its destination because the signal weakens after a certain distance and cannot reach its destination, so the signals Re-construction (amplification) is required. In such cases, a repeater is used.

This distance depends on the data transfer range of the transmission channel being used and can vary from a few meters to a few kilometers.

 A repeater is a device used to regenerate a signal that is on its way through a communication channel. An repeater retrieves the received signal and rebroadcasts it to its destination.

Gateway:

There are a large number of computer networks in the world. Some common examples are computer network of a school, ATM network of bank, computer network of a big company spread in the city etc. Thousands of computer networks exist there. These networks use various hardware and software. Many times, these networks are required to communicate with each other.

For example, companies X, Y and Z do business with each other and therefore want to interconnect their computer networks. Another example is the Internet which includes various types of networks spread around the world.

Different networks are sometimes incompatible with each other. It is like using different languages ​​for conversation. A group of individuals When connecting two or more networks that use different hardware and software, some devices are required that can translate the language of one network into another.

 A gateway is a device that is used to connect different types of networks. A gateway is capable of understanding the address architecture used in different networks and performs basic translations between these address architectures.

Router:

Routers are networking devices that forward the data machine using the shortest path from the source machine to the destination machine. Router is used on the network layer which is the third layer of the OSI model, routers employ two or more LANs or WANS at the IP address to use routing tables.