computer

Computer Network and its Purpose

A computer network is a group of connected computers and devices (like printers and scanners) that can share data, resources, and communicate with each other.

Why We Use Networks

The main purpose of networks is sharing and communication.

For example, instead of using many printers, one printer can be shared. Software and files can also be shared between users. Networks also allow people to communicate easily through messages, calls, and online platforms. Today, networks are very important for businesses, education, and daily life.

Networking Applications

Networks are used in many parts of modern life:

Internet: The largest network that connects people and information worldwide.

Telephone Systems: Mobile and wired phones use networks to communicate.

Satellite and GPS: Help with location, navigation, and communication anywhere.

Monitoring Systems: Track location or status of objects (like GPS or RFID).

Multimedia: Support video calls, online meetings, and streaming.

Remote Services: Include online work, telemedicine, and distance learning.

Network Characteristics (Wired vs Wireless)

Wired Networks: Use cables to connect devices. They are stable and mostly used in offices.

Wireless Networks: Use radio signals (Wi-Fi). They are flexible and common in homes and public places.

Network Topologies

Topology means how devices are arranged in a network:

Bus: All devices share one main cable. Simple but not reliable.

Star: All devices connect to a central device. Most common and reliable.

Ring: Devices form a circle. If one connection breaks, the network is affected.

Mesh: Every device connects to all others. Very reliable but expensive and complex.

Client-Server Network

In this system:

A client requests services (like a computer).

A server provides services (like storing files or websites).

This structure is common in organizations.

Network Size (Coverage Area)

Networks are also classified by size:

PAN: (Personal Area Network) Very small network (personal devices).

LAN: ( Local Area Network) Small area like a building or campus.

MAN: ( Metropolitan Area Network)Covers a city.

WAN: ( Wired Area Network) Large area (countries or global). The Internet is the best example.

Intranet, Extranet, and VPN

Intranet: A private network used inside an organization.

Extranet: Allows limited access to outsiders (like partners).

VPN: A secure connection over the internet that protects data and privacy.