NETWORKING
What is a Computer Network?
A computer network is a group of computers and devices connected together so they can communicate and share resources.
Benefits of Networking
- Share files and data
- Share hardware (printers, scanners)
- Share software
- Communication between users (email, messaging)
- Access to the internet
- Centralized backup and security
Types of Networks
1. LAN (Local Area Network)
A network covering a small geographical area such as:
- School
- Office
- Home
Characteristics
- High speed
- Privately owned
- Low cost to maintain
2. WAN (Wide Area Network)
A network covering a large geographical area.
Examples:
- Banks linking branches
- The Internet
Characteristics
- Covers large distances
- Slower than LAN
- More expensive
Network Devices
1. Router
- Connects networks together
- Directs data packets to correct destination
- Connects LAN to internet
2. Switch
- Connects devices in a LAN
- Sends data only to intended device
3. Hub
- Connects devices in a network
- Sends data to all devices
4. Modem
- Converts digital signals to analog and vice versa
- Used for internet access
5. Network Interface Card (NIC)
- Allows a computer to connect to a network.
Transmission Media
Wired Communication
a) Twisted Pair Cable
- Cheap
- Easy to install
- Used in LANs
b) Coaxial Cable
- Better shielding than twisted pair
- Used for cable internet
c) Fibre Optic Cable
- Very fast
- High bandwidth
- Secure
- Expensive
Wireless Communication
Uses radio waves.
Examples:
- Wi-Fi
- Bluetooth
Advantages:
- Mobility
- Easy to install
Disadvantages:
- Security risks
- Interference
- Slower than wired
Network Topologies
1. Star Topology
All devices connect to a central switch/hub.
Advantages:
- Easy to add devices
- Failure of one device doesn't affect others
Disadvantages:
- If central device fails, whole network fails
2. Bus Topology
Single main cable connects all devices.
Advantages:
- Cheap
- Easy to install
Disadvantages:
- Main cable failure affects all devices
3. Ring Topology
Devices connected in a circular loop.
Advantages:
- Data flows efficiently
Disadvantages:
- Break in one connection affects whole network
Client-Server Network
- Server controls network resources
- Clients request services
Examples:
- School systems
- Banks
Advantages:
- Central control
- Better security
- Easier backups
Peer-to-Peer Network
- No central server
- All computers can share resources equally
Advantages:
- Cheap
- Easy to set up
Disadvantages:
- Less secure
- Difficult to manage
Internet Terms
IP Address
Unique number identifying a device on a network.
Example:
192.168.1.2
MAC Address
Unique hardware address of a device.
Protocol
Rules used for communication.
Examples:
- HTTP – web pages
- HTTPS – secure websites
- FTP – file transfer
- TCP/IP – internet communication
Network Security
Threats
- Hacking
- Viruses
- Phishing
- Malware
Protection
- Firewalls
- Passwords
- Encryption
- Antivirus software
Exercise (25 Marks)
Section A
1. Define a computer network. (2)
2. State two advantages of networking. (2)
3. Distinguish between LAN and WAN. (4)
4. Name the device used to:
a) Connect a LAN to the internet (1)
b) Connect devices within a LAN (1)