A computer network is a group of computers and other devices connected together so that they can communicate and share resources.
Networking is an important part of modern computing. It allows users to share files, printers, Internet connections, applications, and information between connected devices.
Computer networks are used in homes, schools, offices, banks, hospitals, businesses, government organizations, and data centers.
A computer network is a collection of two or more computers or devices connected through wired or wireless communication methods.
In a computer institute, several computers may be connected to:
This allows students and staff to communicate and share resources.
Computer → Switch → Router → Internet
Computer networks provide several important benefits:
A network consists of different hardware and software components.
A client is a computer or device that requests services or resources from another computer.
Examples:
A server is a computer or system that provides services or resources to other devices on a network.
Client → Request → Server
Server → Response → Client
A Network Interface Card (NIC) is a hardware component that allows a device to connect to a network.
NICs may support:
Every network interface has a MAC address, which is used to identify the interface at the network level.
A network switch connects multiple devices within a local network.
For example:
PC 1
↓
Switch ← PC 2
↓
PC 3
A switch forwards network traffic to the appropriate device instead of normally sending it to every connected device.
A router connects different networks and forwards data between them.
For example:
Home Network → Router → Internet
A router may also provide features such as:
A modem is a device used to connect certain types of Internet services to a local network.
An Optical Network Terminal (ONT) is commonly used with fiber-optic Internet connections.
The exact equipment supplied by an Internet Service Provider (ISP) depends on the type of connection.
A Wireless Access Point (WAP) allows wireless devices to connect to a wired network using Wi-Fi.
Laptop )))) Wi-Fi )))) Access Point → Switch → Router
Wireless access points are commonly used in:
Computer networks can be classified according to their geographical coverage.
A Personal Area Network covers a very small area around an individual.
A Local Area Network connects devices within a limited area.
LANs are generally used for high-speed local communication and resource sharing.
A Metropolitan Area Network covers a larger geographical area, such as a city or metropolitan region.
It can connect multiple LANs across different locations.
A Wide Area Network covers a large geographical area.
| Feature | LAN | WAN |
|---|---|---|
| Coverage | Small area | Large geographical area |
| Example | Office network | Network connecting different cities |
| Speed | Generally high locally | Varies depending on connection |
| Ownership | Often privately managed | May use multiple providers/networks |
| Purpose | Local resource sharing | Connecting distant networks |
In a wired network, devices communicate using physical cables.
Wireless networking allows devices to communicate without a physical network cable.
Network Topology refers to the physical or logical arrangement of devices in a network.
All devices are connected to a common communication line.
Advantages:
Disadvantages:
All devices connect to a central device such as a switch.
Advantages:
Disadvantage:
Devices are connected in a circular arrangement.
Advantages:
Disadvantages:
Devices have multiple connections between them.
Advantages:
Disadvantages:
Tree topology uses a hierarchical structure where smaller networks connect to larger network segments.
A network protocol is a set of rules that devices follow to communicate with each other.
| Protocol | Purpose |
|---|---|
| TCP | Reliable transport of data |
| IP | Addressing and routing |
| HTTP | Web communication |
| HTTPS | Secure web communication |
| DNS | Converts domain names into IP addresses |
| DHCP | Automatically provides network configuration |
| FTP | File transfer |
| SMTP | Sending email |
| IMAP | Accessing and synchronizing email |
An IP address identifies a network interface on an IP network and helps devices communicate.
192.168.1.10
IPv4 uses 32-bit addresses.
2001:db8::1
IPv6 uses 128-bit addresses and provides a much larger address space.
Private IP addresses are commonly used inside local networks.
Common IPv4 private ranges include:
A public IP address is used for communication across the public Internet and is generally assigned by an ISP or network provider.
A MAC address is a hardware-level address associated with a network interface.
It is commonly represented in hexadecimal format.
00:1A:2B:3C:4D:5E
A MAC address is different from an IP address:
DNS stands for Domain Name System.
It translates human-readable domain names into IP addresses.
Instead of remembering an IP address, users can type:
DNS helps locate the corresponding network address.
Domain Name → DNS → IP Address → Server
DHCP stands for Dynamic Host Configuration Protocol.
It automatically provides network configuration information to devices.
It can provide:
This reduces the need to manually configure every device.
The Internet is a worldwide network of interconnected networks.
An Intranet is a private network used within an organization.
A company may have an internal website that only employees can access. This can be part of the organization’s intranet.
Network security protects systems, devices, and information from unauthorized access and attacks.
A firewall is a security mechanism that monitors and controls network traffic according to defined rules.
It can help block unauthorized connections while allowing legitimate traffic.
Firewalls may exist as:
Bandwidth refers to the capacity of a network connection to carry data over a given period.
It is commonly measured in:
Higher bandwidth does not automatically mean lower latency. Network performance also depends on factors such as:
Usually refers to how much data can be transferred per second.
Latency is the time taken for data to travel between two points.
For activities such as video calls and online gaming, low latency can be especially important.
Networking allows users to share resources.
Several employees can access a shared printer through the office network instead of connecting each computer directly to the printer.
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