CHAPTER 1: INTRODUCTION TO COMPUTER NETWORKS
1.1 Definition
A computer network is a system where multiple computing devices are connected to
share data, resources, and services.
1.2 Benefits of Networking
Resource sharing (printers, storage)
Faster communication
Centralized data management
Scalability
Cost efficiency
Remote access
1.3 Types of Networks
1. PAN (Personal Area Network)
Very short range
Uses Bluetooth, USB, NFC
2. LAN (Local Area Network)
Small geographical area
Used in schools, offices
High speed (100 Mbps – 10 Gbps)
3. MAN (Metropolitan Area Network)
Covers a city
Managed by ISPs or telecoms
4. WAN (Wide Area Network)
Covers large/geographical areas
Example: The Internet
5. CAN (Campus Area Network)
Connects multiple LANs across a campus
1.4 Network Models
Peer-to-Peer: No central server
Client-Server: Central server manages resources
CHAPTER 2: NETWORK TOPOLOGIES
2.1 Definition
, Topology refers to the layout or structure of a network.
2.2 Types of Topologies
1. Bus Topology
One main cable (backbone)
Cheap but poor reliability
2. Star Topology
All nodes connect to a switch/hub
Easy to manage
Central device failure → network failure
3. Ring Topology
Circular connection
Data travels in one direction
Failure of one device can break the network
4. Mesh Topology
Each device connects to every device
High redundancy
Expensive and complex
5. Hybrid Topology
Combination of two or more topologies
CHAPTER 3: OSI REFERENCE MODEL
3.1 Purpose
A conceptual framework that standardizes network communication.
3.2 Layers and Functions
Layer 7: Application
Interfaces with applications
Protocols: HTTP, FTP, SMTP, DNS
Layer 6: Presentation
Encryption, compression, data translation
Example: SSL/TLS
Layer 5: Session
Manages communication sessions
1.1 Definition
A computer network is a system where multiple computing devices are connected to
share data, resources, and services.
1.2 Benefits of Networking
Resource sharing (printers, storage)
Faster communication
Centralized data management
Scalability
Cost efficiency
Remote access
1.3 Types of Networks
1. PAN (Personal Area Network)
Very short range
Uses Bluetooth, USB, NFC
2. LAN (Local Area Network)
Small geographical area
Used in schools, offices
High speed (100 Mbps – 10 Gbps)
3. MAN (Metropolitan Area Network)
Covers a city
Managed by ISPs or telecoms
4. WAN (Wide Area Network)
Covers large/geographical areas
Example: The Internet
5. CAN (Campus Area Network)
Connects multiple LANs across a campus
1.4 Network Models
Peer-to-Peer: No central server
Client-Server: Central server manages resources
CHAPTER 2: NETWORK TOPOLOGIES
2.1 Definition
, Topology refers to the layout or structure of a network.
2.2 Types of Topologies
1. Bus Topology
One main cable (backbone)
Cheap but poor reliability
2. Star Topology
All nodes connect to a switch/hub
Easy to manage
Central device failure → network failure
3. Ring Topology
Circular connection
Data travels in one direction
Failure of one device can break the network
4. Mesh Topology
Each device connects to every device
High redundancy
Expensive and complex
5. Hybrid Topology
Combination of two or more topologies
CHAPTER 3: OSI REFERENCE MODEL
3.1 Purpose
A conceptual framework that standardizes network communication.
3.2 Layers and Functions
Layer 7: Application
Interfaces with applications
Protocols: HTTP, FTP, SMTP, DNS
Layer 6: Presentation
Encryption, compression, data translation
Example: SSL/TLS
Layer 5: Session
Manages communication sessions
