📘 NETWORKING 1 – Complete and Expanded Explanation
with Real-Life Examples
🔹 I. Definition of Networking
Networking is the process of linking two or more computing devices together for the purpose of
sharing information and resources. It includes the design, implementation, and management of
computer systems that communicate over wired or wireless channels.
📌 Simple Example: When two computers are connected to share a file, a network is formed.
🔹 II. Key Purposes of Networking
1. Communication – Email, messaging, video conferencing
2. Resource Sharing – Printers, files, applications, internet
3. Data Management – Centralized storage and backup
4. Remote Access – Working from different locations
5. Scalability – Easily adding more devices to the system
🔹 III. Types of Computer Networks
Type Description Example
Limited to a small area like a home,
LAN (Local Area Network) School computer lab
school, or building
WAN (Wide Area
Covers large geographic areas The Internet
Network)
MAN (Metropolitan Area
Covers a city or large campus University campus network
Network)
PAN (Personal Area Very small network for personal Bluetooth connection between phone
Network) devices and wireless headset
WLAN (Wireless LAN) LAN but wireless Wi-Fi in a coffee shop
CAN (Campus Area Interconnects LANs within a campus Hospital or school network
Type Description Example
Network) infrastructure
🔹 IV. Network Topologies (Structure of Network Layout)
1. Bus Topology
Single cable connects all devices.
Advantage: Easy to set up.
Disadvantage: One failure affects entire network.
Example: Early computer labs
2. Star Topology
Devices connected to a central switch/hub.
Advantage: Easy to troubleshoot.
Disadvantage: Hub failure affects all.
Example: Modern offices and homes
3. Ring Topology
Devices connected in a circle.
Advantage: Data travels in one direction.
Disadvantage: A single failure can disrupt entire network.
Example: Some university campus layouts
4. Mesh Topology
Every device is connected to every other device.
Advantage: Very reliable.
Disadvantage: Expensive and complex.
Example: Military or critical communication networks
🔹 V. Types of Transmission Media
A. Wired Media
1. Twisted Pair Cable – Common in LAN
2. Coaxial Cable – Used in cable TV networks
3. Fiber Optic Cable – Fast and long-distance
B. Wireless Media
1. Radio Waves – Wi-Fi, FM radio
2. Microwaves – Satellite communication
3. Infrared – TV remotes, short-range data
🔹 VI. Network Devices and Their Functions
Device Function Example
Router Connects different networks Used in home internet setups
Switch Connects devices in a LAN Office network hub
Hub Basic switch without smart routing Simple data sharing
Modem Converts signals for internet Globe/PLDT modem
Access Point (AP) Extends Wi-Fi range Installed in halls or cafes
Firewall Blocks unwanted access Security software or hardware
🔹 VII. Network Models
1. OSI Model (Open Systems Interconnection) – 7 Layers:
Layer Description
7 – Application User interfaces (web browsers)
6 – Presentation Data formatting, encryption
5 – Session Communication between systems
4 – Transport Reliable data transfer (TCP)
3 – Network IP addressing, routing
2 – Data Link MAC addressing, error detection
1 – Physical Cables, switches, wireless
Layer Description
📌 Example: When you browse the internet, all 7 layers work together!
🔷 TCP/IP Model – 4 Layers with Meaning and Examples
The TCP/IP Model (Transmission Control Protocol/Internet Protocol) is a simplified
networking framework used to understand and design internet-based communication. It consists
of 4 layers, each with specific functions.
1. Application Layer
✅ Meaning:
This layer provides interface and services for user applications to communicate over the
network. It is where protocols like HTTP, FTP, SMTP, etc., operate.
📌 Functions:
Sending and receiving data from software (like browsers or email clients)
Ensures proper formatting and delivery to users
🌐 Examples:
Web Browsing: Uses HTTP/HTTPS to access websites
→ e.g., Visiting www.google.com using a browser
Email Communication: Uses SMTP (send), POP3/IMAP (receive)
→ e.g., Sending an email through Gmail
File Transfer: Uses FTP or SFTP
→ e.g., Uploading a file to a website
2. Transport Layer
✅ Meaning:
This layer is responsible for end-to-end communication, data delivery, and error handling
between two devices. It uses protocols like TCP and UDP.
📌 Functions:
Divides large data into smaller packets
Ensures packets are sent in the correct order
Manages errors and retransmissions
🌐 Examples:
TCP (Transmission Control Protocol): Reliable communication (e.g., loading a
webpage, downloading a file)
→ e.g., Watching YouTube with consistent video loading
UDP (User Datagram Protocol): Faster, no error-checking (e.g., live streaming, online
gaming)
→ e.g., Playing a multiplayer game or Zoom call
3. Internet Layer
✅ Meaning:
This layer is responsible for routing and delivering packets across networks using IP
addresses. It chooses the best path for data to travel.
📌 Functions:
Assigns source and destination IP addresses
Breaks packets into IP datagrams
Routes data between networks
🌐 Examples:
IP (Internet Protocol): Assigns addresses like 192.168.1.1
→ e.g., Your device is assigned an IP when connecting to Wi-Fi
ICMP (Internet Control Message Protocol): Used by ping/traceroute tools
→ e.g., Checking if a website is reachable with ping google.com
4. Network Access Layer (also called Link or Physical Layer)
✅ Meaning:
This layer handles the physical connection to the network and data transfer over cables or
wireless signals. It defines how bits are sent and received through network devices.
📌 Functions:
Converts data into electrical, light, or radio signals
Manages hardware addressing (MAC addresses)
Handles error detection at the physical level
🌐 Examples:
Ethernet: Wired LAN connection using RJ45 cable
→ e.g., Connecting your PC to a router via cable
Wi-Fi: Wireless network connection
→ e.g., Using your phone to connect to the internet
MAC Addressing: Unique address of a device’s network card
→ e.g., 00:1A:2B:3C:4D:5E used for communication within LAN
✅ Summary Table:
Layer Meaning Example
User interface & communication Web browsing, email, file
Application
services sharing
Reliable delivery of data between TCP for web, UDP for
Transport
devices games
Assigning & locating
Internet Routing data using IP addresses
devices
Network Wi-Fi, Ethernet, MAC
Physical transmission of data
Access address
🔹 VIII. Network Protocols
Protocol Purpose Example
TCP/IP Standard for communication Internet
HTTP/HTTPS Web browsing Opening YouTube
FTP/SFTP File transfer Uploading a file to a server
SMTP/POP3/IMAP Email sending/receiving Gmail or Outlook
Protocol Purpose Example
DNS Domain to IP address google.com → IP
DHCP Assigns IP addresses automatically New device joining Wi-Fi
🔹 IX. IP Addressing & Subnetting
IPv4: 192.168.1.1 (32-bit)
IPv6: 2001:0db8:85a3::8a2e:0370:7334 (128-bit)
Subnetting: Divides networks into smaller parts for better management.
📌 Example: A school's LAN may use IPs from 192.168.0.0 to 192.168.0.255.
🔹 X. Network Security Basics – Meaning and Examples
Network security involves protecting data, devices, and systems from unauthorized access,
attacks, and data loss while using a network (especially the internet). Below are the core tools
and techniques used to keep networks secure:
🔐 1. Antivirus and Firewall
✅ Meaning:
Antivirus is software that detects, prevents, and removes malicious software (malware)
such as viruses, worms, and trojans.
Firewall is a system (hardware or software) that monitors and controls incoming and
outgoing network traffic based on security rules.
🌐 Example:
Antivirus: Windows Defender or Avast blocks a trojan file downloaded from a
suspicious website.
Firewall: A school firewall blocks access to certain websites like social media during
school hours.
🔐 2. Encryption (SSL/TLS)
✅ Meaning:
Encryption is the process of converting data into a code to prevent unauthorized access. SSL
(Secure Sockets Layer) and TLS (Transport Layer Security) are encryption protocols used to
secure data during transmission over networks.
🌐 Example:
Websites that use HTTPS instead of HTTP (like https://facebook.com) use SSL/TLS
encryption to protect data such as login credentials from being stolen.
🔐 3. Strong Passwords and Authentication
✅ Meaning:
A strong password uses a mix of uppercase, lowercase, numbers, and symbols to make
it harder to guess.
Authentication verifies a user's identity. It can involve multiple steps (called multi-
factor authentication, or MFA), such as a password and a code sent to your phone.
🌐 Example:
Password: J@ne2025! is stronger than jane123.
MFA: When logging in to Gmail, you're asked for your password and then a code sent to
your phone.
🔐 4. Access Control Lists (ACLs)
✅ Meaning:
ACLs are rules set by network administrators that define who can access what resources on a
network, and what operations (read, write, delete) they are allowed to perform.
🌐 Example:
In a school's network:
o Students can only access shared folders.
o Teachers have access to grading systems and administrative tools.
o Guests are restricted from accessing internal files.
🔐 5. Virtual Private Network (VPN)
✅ Meaning:
A VPN is a secure connection over the internet that hides your IP address and encrypts your
data, making your online activities private—even on public Wi-Fi.
🌐 Example:
A student connects to a VPN at a coffee shop so they can safely access their school’s
private network.
Remote employees use VPNs to securely connect to their company’s internal systems.
✅ Summary Table:
Security Tool Meaning Example
Blocks malware and controls Avast blocking a virus; firewall
Antivirus & Firewall
traffic blocks YouTube
Converts data into HTTPS protects passwords during
Encryption (SSL/TLS)
unreadable code login
Strong Passwords & Prevents unauthorized
Using MyP@ss123! + phone code
Authentication access
Limits user access based on
Access Control Lists (ACLs) Students can't access teacher's files
rules
VPN (Virtual Private Secures your connection and
Safe internet use in public areas
Network) hides IP
🔹 XI. Common Network Issues and Troubleshooting
Problem Possible Cause Solution
No Internet Router/modem offline Restart router
IP Conflict Two devices same IP Release and renew IP
Slow Network Too many users Upgrade bandwidth
Wi-Fi Drops Weak signal Move closer or use extender
🔹 XII. Real-World Applications of Networking
Banks use secure networks for ATMs and transactions.
Schools use networks for e-learning platforms.
Hospitals share medical records over secure networks.
Airports rely on networking for flight operations.
Government offices maintain centralized databases using networks.
🔹 XIII. Future Trends in Networking
1. 5G Technology – Faster wireless communication
2. IoT (Internet of Things) – Smart homes and smart cities
3. Cloud Networking – Online services like Google Drive
4. SDN (Software-Defined Networking) – Programmable networks
5. Cybersecurity Focus – Increased need for secure systems
✅ Summary
Networking 1 introduces students to the core concepts of how devices communicate and
share resources. From small home networks to the massive global internet, networking is the
foundation of modern technology. Understanding devices, topologies, protocols, IP addressing,
and security is essential in today’s digital world.
