This is the era of Information Technology (IT). The impact of information technology on the evolution of modern civilization is immense. Information technology requires data communication, telephone, mobile phone, television, and computer network systems. Today, the introduction of the global internet communication system is constantly advancing civilization. At present, communication refers to the transfer of data from computer to computer. The whole world is in the hands of people today. People can stay in the ocean of information and exchange data worldwide through the Internet. In this blog, you’ll get an overall basic idea on Computer networks and different types of Networking Systems. 

Computer Network: 

A computer network is an integrated interconnected system set up for the exchange and processing of information between two or more computers located side by side or remotely. The word ‘network’ means ‘to spread like a net’. When multiple computers can be connected to maintain communication and share resources, it is called a computer network. Simply, the scheme of sharing a computer’s hardware or software to be used by one or more other computers is called a computer network. This is a connection between several computers. The U.S. Department of Defense launched the Advanced Research Projects Agency Network (ARPANET) in 1969. This is the first step of humans in the world of the computer network.

Internet

The technology used to transfer information from computer to computer using telecommunication technology is called the Internet. The Internet is a large network composed of unlimited networks across the globe. A lexical analysis of the Internet reveals that it is an acronym for International Network. Although the widespread use of the Internet began in 1990, its real journey began in 1969 through the launching of ARPANET. Although the Internet was started in 1990, it was not called by that name before 1994. The term Internet was used in 1994 and became widely known. China is currently the top country in terms of internet usage. India, the United States, Brazil, and Japan are ranked second, third, fourth, and fifth respectively. In this case, Bangladesh is 26th among the countries of the world. 

Networking or Internetworking:

The whole process of establishing a computer network is called Networking/Internetworking. Networking requires a minimum of two computers. Internetworking is the communication of a computer connected to a network with a computer connected to a different network. As such, the Internet is also called the network of network or Internet work. The Internet is a milestone in today’s world. It is a huge source of information. It is one of the means of communication and exchange of information. Information can be transmitted and retrieved in various ways through the Internet. As a result of innovations, the facilities of the internet and aggregation of information are increasing day by day. New words and topics are being created. CyberCash, Cyber ​​Cafe, Cyber ​​Coin, Internet Commerce, Internet Phone, Electronic Mail (E-mail), Electronic Book (E-book), Electronic Library, Electronic Campus, etc. are some of the terms. 

Computer Network Operating System:

Suitable software or programs are needed to control the operation of one computer with another. Such software is called a network operating system.

Network operating systems perform the functions of controlling the computers and components connected to the network, exchanging information, sharing resources, providing security to the system, etc. Such operating systems are usually more powerful than operating systems like Windows or Mac.

Unix, Novell Netware, Microsoft Windows NT, etc. are some of the notable network operating systems.

Nodes, Servers & Workstations:

Each computer connected to a network is called a Node. The nodes that provide computer services are called servers and the nodes that receive services are called Workstations. The network usually has only one server and several workstations.

Uses of a computer network: 

The concept of a computer network is an important means of communication in today’s world. The expansion of the global computer network is the latest use of computer technology. At present, various types of organizations are creating their computer networks to facilitate their work. The advantage of a computer network is that many computers are connected and even if one or two of them go bad, not all the work stops, it can be done with the good ones. 

The computer network is used for the following purposes: 

1. Files (documents, images, audios, videos, etc.) or information sharing,

2. Hardware resource sharing,

3. Software resource sharing,

4. Data preservation,

5. Data protection, 

6. Data collection, 

7. Exchanging messages,

8. Social communication, etc.

Classification of Computer Network:

A. Networks can be divided into three main categories based on network control structure and type of service delivery as follows: 

a. Client-Server Network: 

Such networks are made up of one or more dedicated servers. This dedicated server provides the necessary services for the client PC. The services mainly include files, print messages, databases, applications, etc. 

b. Peer-to-Peer Network: 

A peer-to-peer network is usually a network of five to ten computers that is mainly used for file or printer sharing, internet sharing, playing network games, or such small tasks. The peer-to-peer network system does not have a specific server. In this type of network, each PC plays an equal role in resource sharing. There are no dedicated servers, so there is no classification of PCs considering their importance. Each PC is responsible for its data security. The PC user determines his files or data which will be open to others on the network.

c. Mixed or Hybrid Network: 

A mixed or hybrid network is a combination of a client-server and peer-to-peer network. Usually, the client-server part predominates in the hybrid network. However, in addition to this, part of the peer-to-peer network is connected here in a limited way. In this process, the computer or nodes are placed in a special place without being directly connected to the central computer and then connected by a dynamic connection. 

B. Computer networks can be divided into the following types based on their size and area coverage:

1) Personal Area Network (PAN): 

A network system for exchanging information by connecting various devices (telephone and personal digital assistants) close to a person is called a Personal Area Network (PAN). PANs can be used to communicate between personal devices or to communicate with higher-level networks and the Internet.

 The width of the PAN is usually limited to a few meters. Notable devices used in PAN are laptops, PDAs, portable printers, mobile phones, etc. PAN can be connected by the USB bus and Firewire bus. 

Characteristics of PAN:

1. PAN is generally used to establish connections among personal devices. 

2. The range of PAN is usually limited to 10 meters. 

3. PAN can be created by wire connection using computer buses such as USB or Firewire.

4. Wireless network technology makes it possible to create a wireless Personal Area Network. 

2) Local Area Network (LAN): 

Local Area Network (LAN) is used for short-range space within a small and specific geographical area. Usually, the network that connects the required number of computer terminals or any other peripheral device (such as a printer) within a space of 10 km or less than that is called LAN. It is mostly used to establish a network between a building and two or three adjacent buildings. It is usually used in school-college or university, any big office building. Each computer located in LAN can share data, files, various expensive devices such as scanners, laser printers, etc. among themselves. LAN’s Topology is usually Star, Ring, or Broadcast Channel Method. 

Its transmission media is usually twisted pair cable, co-axial cable, or optical fiber. The main reason for the emergence of the Local Area Network was the interaction between different users through computers, data transfer, and the ability to use one person’s CPU to another, and so on. 

Characteristics of LAN:

1. Its activities are limited between 100-1000 meters coverage. 

2. Computers are connected through series connections in LAN. 

3. For data transfer, there is high bandwidth in LAN. 

4. The data transfer rate of LAN is typically from 10 to 1000 Megabytes/sec. 

5. The network installation and maintenance process are easy and of low cost. 

6. It is generally owned by an individual or an organization. 

3) Metropolitan Area Network (MAN): 

A network of computers and devices located in different places of the same city is called the Metropolitan Area Network (MAN). It is a wider network than LAN up to 50-75 miles. Usually, multiple routers, switches, hubs, telephone lines, modem, or in some cases microwaves are used as transmission media in MAN. Its distance is usually based on the area of a city. This type of network system is usually used for communication between different branch offices of a bank, educational institution, or industrial organization. 

Characteristics of MAN:

1. Its activities are confined to a specific town, city, or region. 

2. There is a moderate bandwidth for transferring data with MAN. 

3. MAN can be owned both publicly or privately. 

4. A MAN can usually cover an area of 100 Km. 

5. The setup cost of MAN is moderate. 

6. The data transfer speed of MAN can be about 100 Mbps (Megabytes per second) to 1 Gbps (Gigabytes per second). 

4) Wide Area Network (WAN): 

A computer network that covers a large geographical location is called a Wide Area Network (WAN). A computer networking system is established among different important cities of a country with this network. Generally, LAN, MAN, or another computer device located in different cities around the world can also be connected through Wide Area Network. 

However, the whole process of WAN depends on the physical line, fiber optic cable, satellite transmission, and microwave transmission. In the case of large countries such as India, America, etc., the satellite system is also used as the transmission media. Computer scientists and technologists have connected the whole world through Wide Area Networks. The Internet (International Network) is an example of the world’s widest WAN. 

Characteristics of WAN: 

1. The data transfer speed of WAN is from 56 kbps (Kilobytes per second) to 1.544 Mbps. 

2. The structure of such networks is quite complex.

3. Such kind of network usually covers a wide geographical area. 

4. Devices used in such networks are routers, modems, WAN switches, etc.

Advantages of WAN: 

1. Various statistical data, journals, books, films, etc. can be collected and used through WAN. 

2. Data and news can be sent from one part of the world to another within a short time. 

3. Correspondence can be sent anywhere in the world through an electronic mailing system. 

4. The patients can talk to the doctor from home and take the necessary treatment. 

5. Bulletin boards can be formed individually or collectively. 

6. Online shopping can be done. 

7. The whole network world can be observed sitting at home.

8. Students can participate in online classes without going to school or college. 

Disadvantages of WAN: 

1. There is low bandwidth for data transfer with WAN. 

2. Set up a process of WAN is more costly compared to other networks. 

3. One can get lower speeds of data transfer of 10-20 Mbps.

5) Virtual Private Network (VPN):

If a device is connected to a network via an encrypted connection through the Internet, it is called a Virtual Private Network. Encrypted means information converted into a code that no unauthorized person can see or read. Encryption is commonly used at the corporate level. VPN creates a secure connection between two networks on the Internet. Most people use VPNs primarily to access regionally blocked sites, to protect the privacy of information, and to protect them from being tracked while browsing sensitive content. Users can access a private network remotely via a virtual point-to-point connection.

Almost all VPN providers have a desktop, android, iOS app, and browser extensions for virtual private network access. These are usually cross-platform services. These are also very easy to use by signing up from their sites. Some of the popular VPN providers are Samsung Max (Free), Express VPN, TunnelBear, Hotspot shield, etc.

Uses of VPN: 

Virtual Private Network is used for the following purposes: 

1. Browsing geo-restricted content,

2. Keeping personal information safe,

3. Hiding one’s real location,

4. Protecting one’s privacy when using torrents or other sensitive web pages.

Types of VPN: 

Most providers have two types of VPN plans-Free and Paid. Sometimes using a VPN will be enough with a free plan. And if one has to use it regularly for official or business purposes, then he can take a good paid plan. Paid plans usually do not have ads. The number of servers and the speed is high in a Paid VPN. Some more benefits are also available in the paid plan.

6) Wireless Local Area Network (WLAN):

WLANs operate like a LAN, using wireless network technology such as Bluetooth, Wi-Fi (Wireless Fidelity). Such forms of networks, usually used in the same kinds of implementations as LANs, do not demand that computers depend on external cables to connect to the network.

7) Campus Area Network (CAN):

Campus Area Networks are usually used in universities, large K-12 school districts, or small businesses. CANs are larger than LANs but smaller than MANs. They can be spread across multiple buildings that are relatively close to each other so that users can share resources.

8) Storage Area Network (SAN):

Such types of networks do not focus on a LAN or WAN as a single high-speed network that links distributed pools of computing devices to multiple servers. They instead relocate storage resources away from the network and place them within their high-performance network. SANs should be used in the same manner as a disk connected to a computer. Storage area networking types include converged, virtual, and unified SANs.

9) System-Area Network (also known as SAN):

In the past two decades, this term is quite new. It explains a relatively local network designed to provide speed connection to server-to-server (cluster) applications, storage area networks, and processor-to-processor applications.  The SAN-connected computers work with very high speeds as a single system.

10) Passive Optical Local Area Network (POLAN):

To resolve issues about supporting conventional Ethernet protocols and network applications such as POE (Power Over Ethernet), the POLAN technology can be integrated into organized cable networks as an alternative to standard switch-based Ethernet LANs. POLAN uses optical splitters as a dot-to-multipoint architecture to split an optical signal into multiple signals between a single strand of optical fiber mode to serve users and devices.

11) Enterprise Private Network (EPN):

These kinds of networks are built and owned by companies that want to securely connect their different locations to share computer resources.

12) Generative Adversarial Network (GAN):

It is a form of neural network technology built with a great deal of potential in the artificial intelligence world. There are two neural networks within a generative adversarial network: a generative network and a discriminative network. They work together to simulate conceptual tasks at a high level.

C. The network is classified into two more classes based on ownership. These are:

1. Private Network: 

According to the IP addressing architecture, those networks are called private networks where networks are formed using private IP address space. IPv4 and IPv6 specifications determine the private IP range. Local area networks typically use IP addresses of all these ranges in residential areas and offices. A private network is not accessible for all.  

2. Public Network: 

A public network is an open or unrestricted network for all. Anyone can access this network. All of these networks are made up of public IP addresses of IPv4 and IPv6 specifications. Anyone connected to the Internet can access this network. There are some rules and regulations for using these networks. However, since it is a public network, there is a risk to the security of personal information of the users.

D. The network based on switching is divided into another three parts those are as follows: 

a) Circuit-Switched Network: 

Circuit switching is a method of implementing a telecommunication network that establishes a dedicated communication channel (circuit) between the hosts of the two networks before the communication of the two devices. In circuit switching, the actual data determines the path before transmission begins. A differentiating example of a circuit-switched network is the primary analog telephone network.

b) Message-Switched Network: 

Message switching is a network switch technique in which the data is completely stored from the source host to the destination host. Each intermediate switch on the network saves the entire data during data routing. If the entire network is not active for sending data or the network is shut down, the message switched network stores the data and delays sending this data until any means are available to make the data accessible.

c) Packet-Switched Network: 

A packet-switched network is a type of computer network that transmits data in the form of small packets. Each data contains the address of the source and destination. The packet-switched network divides each data into smaller packets and the packet is given a title containing the destination information. Each packet is sent to the destination network using this title. It collects data from the received packets at the destination and converts it to the original data.

E. Based on the construction strategy, there are two additional kinds of networks those are: 

1) Point to Point Network: 

Point to point network is a networking system in which two computers or hosts are directly connected. A good example of a point-to-point network is the conversation between two cell phones. There are two mobile phones with a point-to-point connection in a phone call.

2) Broadcast or Multipoint Network: 

Broadcast or Multipoint Network is a system in which a computer or host is connected to multiple computers or hosts at once. If a computer shares data, many computers on the network can receive it. 

Conclusion

Computer networks have become an integral part of our interconnected world, enabling seamless communication and data sharing across vast distances. The evolution of network technologies and the advent of the internet have revolutionized how we access information, conduct business, and interact with one another. From local area networks (LANs) within homes and offices to wide area networks (WANs) connecting global organizations, computer networks have transformed the way we live and work. As technology continues to advance, the need for robust and secure networks will only grow, pushing the boundaries of innovation and connectivity. It is through effective design, implementation, and management of computer networks that we can harness the full potential of digital connectivity in our modern society.

Hopefully, you have acquired a much better knowledge about the computer network and various types of networks. In my next article, I’ll discuss on various kinds of Network Topology. Stay connected and contact us for getting more basic ideas on computer networking in detail.