Computer networks form the backbone of modern communication. A network is a collection of computers, servers, printers, and other devices connected together so that they can share data and resources. When two or more devices are linked through a communication medium such as cables, optical fibres, or wireless signals, they are said to form a computer network. The primary goal of networking is resource sharing, which includes sharing hardware, software, files, and internet connections, thereby reducing cost and improving efficiency.
In this chapter, we will study the basic concepts of networking including its need and advantages, types of networks based on size and geographical spread, network topologies, and the essential hardware components that make networking possible. We will also learn about the Internet, the World Wide Web, and various communication protocols such as TCP/IP and HTTP. Understanding these fundamentals is essential because almost every modern device, from a mobile phone to a cloud server, depends on networking concepts.
The study of networking also introduces important terminology such as nodes, servers, clients, NIC (Network Interface Card), switches, routers, and modems. By the end of this chapter, you will be able to classify networks as LAN, MAN, and WAN, describe the different network topologies such as star, bus, ring, and mesh, and appreciate how data travels across the Internet using the TCP/IP protocol suite. This knowledge forms the foundation for advanced topics like web services, cloud computing, and artificial intelligence which are covered in later chapters.
Networking is not an option today but a necessity. Organisations and individuals need to share information instantly, access common databases, and communicate efficiently. Some of the key advantages of networking are listed below.
A network works on the client-server model where a central computer called the server provides services, and the computers that request services are called clients. Alternatively, in a peer-to-peer model, all computers have equal status and can both request and provide services. This flexibility makes networks suitable for both small homes and large enterprises.
Based on the geographical area covered, networks are classified into three main categories.
A LAN connects computers within a limited physical area such as a school, office building, or home. It typically covers a range of a few metres to a few kilometres. LANs are privately owned, have high data transfer speeds, and use cables such as twisted pair or Ethernet. Examples include the computer lab network of a school and a home Wi-Fi network.
A MAN covers a larger area than a LAN, typically a city or a town. It is used by government agencies, cable television networks, and large organisations to connect multiple LANs spread across a metropolitan region. MANs use high-speed optical fibre links and have moderate data transfer rates.
A WAN spans very large geographical areas such as a country, a continent, or the entire world. The Internet is the largest example of a WAN. WANs are created by connecting multiple LANs and MANs through leased lines, satellites, and optical fibres. Data transfer rates are lower compared to LANs because signals must travel longer distances.
A PAN is the smallest type of network, used to connect personal devices such as a smartphone, tablet, laptop, and smartwatch within a range of about ten metres. Bluetooth and infrared technologies are commonly used to create PANs.
The physical arrangement in which computers and other devices are connected in a network is called the network topology. The choice of topology affects cost, speed, and reliability of the network.
In a star topology, all nodes are connected to a central device such as a hub or a switch. Every node communicates with other nodes only through the central device. If one node fails, the rest of the network continues to function. However, if the central device fails, the entire network stops working.
In a bus topology, all nodes are connected to a single common backbone cable. Data travels in both directions along the cable and each node listens for data meant for it. A bus topology uses the least amount of cable and is easy to install, but if the main cable breaks, the whole network fails. The ends of the cable are terminated with terminators to prevent signal reflection.
In a ring topology, each node is connected to exactly two neighbouring nodes, forming a closed loop. Data travels in one direction around the ring, passing through each node until it reaches the destination. A token passing mechanism is often used to avoid collisions. Failure of a single node can break the ring and disrupt communication.
In a mesh topology, every node is connected to every other node through a dedicated link. This provides high reliability because there are multiple redundant paths for data. However, it requires a large amount of cable and is expensive, so it is usually used in critical applications such as banking networks and military systems.
Several hardware devices are used to build and manage networks. Understanding each device is important for both theory and practical examinations.
Communication media are the physical or wireless channels through which data travels from one device to another. They are broadly divided into guided (wired) and unguided (wireless) media.
Guided media include twisted pair cables (used in telephone lines and LANs), coaxial cables (used in cable television), and optical fibre cables (used for long-distance high-speed communication). Optical fibres transmit data as pulses of light and are immune to electromagnetic interference.
Unguided media use electromagnetic waves to transmit data without any physical cable. Examples include radio waves, microwaves, and infrared waves. Wi-Fi, Bluetooth, and satellite communication all depend on unguided media. Wireless communication is convenient but can be affected by obstacles, weather, and interference.
The Internet is a global network of networks that connects billions of devices worldwide using the TCP/IP protocol suite. Each device connected to the Internet is identified by a unique IP address, which can be IPv4 (32-bit) or IPv6 (128-bit). Domain names such as www.example.com are easier to remember than numeric IP addresses, and the Domain Name System (DNS) translates domain names into IP addresses.
A protocol is a set of rules that govern how data is exchanged between devices. Important protocols include:
The World Wide Web (WWW) is an information system on the Internet where documents and other web resources are identified by URLs and can be accessed using web browsers. A website is a collection of related web pages, and a web server is a computer that hosts these pages and delivers them to clients. Web pages are written in HTML (HyperText Markup Language) and can contain text, images, videos, and links. Search engines such as Google index web pages and help users find the information they need.
| Term | Full Form | Meaning |
|---|---|---|
| LAN | Local Area Network | Connects devices within a small area such as a building |
| MAN | Metropolitan Area Network | Covers a city or town |
| WAN | Wide Area Network | Covers a country, continent, or the whole world |
| PAN | Personal Area Network | Connects personal devices within about 10 metres |
| NIC | Network Interface Card | Hardware that connects a computer to a network |
| TCP | Transmission Control Protocol | Ensures reliable delivery of data packets |
| IP | Internet Protocol | Handles addressing and routing of packets |
| HTTP | HyperText Transfer Protocol | Used to transfer web pages |
| FTP | File Transfer Protocol | Transfers files between client and server |
| DNS | Domain Name System | Converts domain names to IP addresses |
| Topology | Description | Advantage | Disadvantage |
|---|---|---|---|
| Star | All nodes connected to a central hub or switch | Easy to install and troubleshoot | Fails if central device fails |
| Bus | All nodes on a single backbone cable | Uses least cable | Fails if main cable breaks |
| Ring | Nodes form a closed loop | Data travels in an organised way | Failure of one node breaks the ring |
| Mesh | Every node connected to every other node | Highly reliable | Very expensive |
Networking is a core concept of computer science that connects devices and people across the world. We learned that networks are classified into PAN, LAN, MAN, and WAN based on their size, and that the choice of topology such as star, bus, ring, or mesh affects cost, speed, and reliability. Networking devices like the NIC, modem, hub, switch, router, and repeater perform specific roles in building a network, while guided and unguided media carry data between devices. The Internet, built on the TCP/IP protocol suite, enables services such as the World Wide Web, email, and file transfer. Mastery of these fundamentals prepares students for advanced topics such as web services, cloud computing, and artificial intelligence discussed in later chapters.