12. Computer Networks Definition of Network, Types of Networks (LAN, MAN, WAN), Network Topologies, Network Devices (Router, Switch, Hub)
A computer network is a system in which two or more computers and other devices are connected together so they can communicate, share resources, and exchange data.
Networks allow computers to share files, printers, internet connections, and software. In modern society, computer networks are essential for communication, business operations, education, banking, and many other activities.
Examples of networks include office networks, school computer labs, and the global internet.
A computer network is a collection of interconnected computers and devices that communicate with each other through communication channels in order to share resources and information.
A network typically consists of the following elements:
Example:
In a school computer lab, multiple computers connected to the same system and internet connection form a network.
Benefits of computer networks include:
Computer networks can be classified based on their geographical coverage area.
A Local Area Network (LAN) is a network that connects computers within a small geographical area such as a room, building, school, or office.
Characteristics of LAN:
Examples:
Advantages of LAN:
A Metropolitan Area Network (MAN) covers a larger geographical area than a LAN, typically a city or metropolitan region.
It connects multiple LANs within a city.
Characteristics of MAN:
Examples:
A Wide Area Network (WAN) covers a very large geographical area such as a country or even the entire world.
WAN connects multiple LANs and MANs together.
Characteristics of WAN:
The most common example of WAN is the Internet, which connects millions of networks worldwide.
Other examples:
A network topology refers to the physical or logical arrangement of computers and network devices in a network.
It describes how devices are connected and how data flows between them.
Common network topologies include:
In a bus topology, all computers are connected to a single main communication cable called the bus.
Characteristics:
Disadvantages:
In a star topology, all devices are connected to a central device such as a switch or hub.
Characteristics:
Disadvantages:
Star topology is the most commonly used topology in modern networks.
In a ring topology, each computer is connected to exactly two other computers, forming a circular structure.
Characteristics:
Disadvantages:
In a mesh topology, every device is connected to multiple other devices.
Characteristics:
Disadvantages:
Mesh topology is commonly used in large or critical networks where reliability is important.
Network devices are hardware components that connect computers and control how data moves within a network.
A router is a network device that connects different networks and directs data between them.
Routers determine the best path for data to travel across networks.
Functions of a router:
Example:
Home internet routers connect local devices (phones, laptops, computers) to the internet.
A switch is a network device that connects multiple devices within the same network and efficiently directs data to the correct device.
Unlike a hub, a switch sends data only to the intended recipient.
Characteristics:
Example:
Office networks often use switches to connect multiple computers.
A hub is a basic networking device that connects multiple computers in a network.
When a hub receives data from one computer, it broadcasts the data to all connected devices.
Characteristics:
Because hubs send data to every device, they can cause network congestion.
Modern networks rarely use hubs and prefer switches.
Computer networks enable computers and devices to communicate and share resources efficiently. Networks may vary in size, from small local networks to global systems such as the internet. Understanding different network types, topologies, and devices helps in designing efficient communication systems. Devices like routers, switches, and hubs play a vital role in connecting computers and managing data transmission within networks. Computer networking has become a fundamental component of modern information technology infrastructure.