NETWORKING DEVICES Lesson Note
Learning Objectives
This SS3 Computer Hardware & GSM Repair lesson note covers NETWORKING DEVICES for First Term, Week 4.
Lesson Note
Learning Objectives
By the end of the lesson, students should be able to:
1. Define a computer network.
2. Explain the meaning of networking devices.
3. Identify common networking devices.
4. State the functions of different networking devices.
5. Differentiate between a hub, switch and router.
6. Explain the functions of a modem, network interface card and wireless access point.
7. Explain the uses of repeaters, bridges, gateways and firewalls.
8. Identify common network cables and connectors.
9. State common network problems and basic troubleshooting methods.
10. Explain how to care for and maintain networking devices.
A. MEANING OF A COMPUTER NETWORK
A computer network is a system in which two or more computers or electronic devices are connected together so that they can communicate and share resources.
A network may allow users to share:
- Files and folders
- Printers
- Internet connections
- Applications
- Data
- Storage resources
- Other hardware and services
B. TYPES OF NETWORK
1. LAN (Local Area Network): Covers a small geographical area such as a classroom, school, office or computer laboratory.
2. MAN (Metropolitan Area Network): Covers a city or large geographical area.
3. WAN (Wide Area Network): Covers a very large geographical area, such as different states or countries.
4. WLAN (Wireless Local Area Network): A LAN that uses wireless communication, usually Wi-Fi.
C. MEANING OF NETWORKING DEVICES
Networking devices are hardware components used to connect computers and other electronic devices, control communication between them, transmit data, or provide access to a network.
Networking devices are important because computers cannot effectively communicate with one another over a network without appropriate hardware.
Common networking devices include:
1. Network Interface Card (NIC)
2. Hub
3. Switch
4. Router
5. Modem
6. Wireless Access Point (WAP)
7. Repeater
8. Bridge
9. Gateway
10. Firewall
11. Wireless router
D. NETWORK INTERFACE CARD (NIC)
A Network Interface Card (NIC) is a hardware component that allows a computer or other device to connect to a network.
A NIC may be:
- Wired
- Wireless
A wired NIC normally uses an Ethernet cable, while a wireless NIC allows connection through Wi-Fi.
FUNCTIONS OF A NIC
1. Connects a computer to a network.
2. Sends data from the computer to the network.
3. Receives data from the network.
4. Provides the hardware interface required for network communication.
5. Uses a unique MAC address to identify the network interface.
Examples
- Ethernet network card
- Wireless network adapter
- USB Wi-Fi adapter
E. HUB
A hub is a networking device used to connect several computers or other network devices together.
When a hub receives data, it generally sends the data to all connected ports rather than sending it only to the intended device.
FUNCTIONS OF A HUB
1. Connects multiple devices in a network.
2. Receives network signals.
3. Repeats incoming data to its connected ports.
4. Allows connected devices to communicate.
DISADVANTAGES OF A HUB
1. It sends data to multiple ports unnecessarily.
2. It can create more network traffic.
3. It is less efficient than a switch.
4. Network performance can decrease as traffic increases.
5. It provides little control over network traffic.
Modern networks therefore commonly use switches instead of hubs.
F. SWITCH
A switch is a networking device used to connect several devices within a network, especially a LAN.
Unlike a traditional hub, a switch can examine the destination information of network frames and forward traffic through the appropriate port.
FUNCTIONS OF A SWITCH
1. Connects computers and other devices on a LAN.
2. Receives network data.
3. Forwards data to the appropriate device.
4. Reduces unnecessary network traffic.
5. Improves network efficiency.
6. Allows several devices to communicate on the same network.
TYPES OF SWITCHES
a). Unmanaged Switch
An unmanaged switch is simple to install and normally works without complicated configuration.
b). Managed Switch
A managed switch can be configured and monitored by a network administrator.
Managed switches may provide features such as:
- VLAN configuration
- Traffic monitoring
- Port management
- Security controls
G. ROUTER
A router is a networking device that connects different networks and directs data packets from one network to another.
For example, a router in a home or school network can connect the local network to the Internet.
FUNCTIONS OF A ROUTER
1. Connects different networks.
2. Determines suitable paths for data packets.
3. Forwards packets between networks.
4. Connects a local network to the Internet.
5. May provide DHCP services.
6. May perform Network Address Translation (NAT).
7. Some routers provide firewall and security functions.
Example
A school computer laboratory may contain many computers connected to a switch. The switch can connect the computers within the local network, while a router can provide communication between the local network and the Internet.
H. MODEM
The word modem comes from modulator-demodulator.
A modem is a device that enables digital devices to communicate over certain telecommunications connections by converting signals into forms suitable for transmission and converting received signals back.
FUNCTIONS OF A MODEM
1. Provides communication between a network and a telecommunications service.
2. Converts signals for transmission over the communication medium.
3. Receives and converts incoming signals.
4. Provides access to certain types of Internet services.
Modern Internet equipment may combine the functions of a modem, router, switch and wireless access point in one device.
I. WIRELESS ACCESS POINT (WAP)
A Wireless Access Point (WAP) is a networking device that allows wireless devices such as laptops, smartphones and tablets to connect to a wired network using Wi-Fi.
FUNCTIONS OF A WAP
1. Provides wireless network connectivity.
2. Allows Wi-Fi devices to join a network.
3. Connects wireless devices to a wired network.
4. Helps extend wireless network coverage.
5. Allows several wireless devices to communicate through the network.
Examples of Devices That Can Connect to a WAP
- Smartphones
- Laptops
- Tablets
- Wireless printers
- Smart devices
J. REPEATER
A repeater is a networking device used to receive and retransmit a network signal to extend the communication distance.
Network signals can become weaker as they travel over long distances. A repeater helps extend the usable range of the signal.
FUNCTIONS OF A REPEATER
1. Receives network signals.
2. Regenerates or retransmits signals.
3. Extends network coverage.
4. Helps overcome limitations caused by signal distance.
Example
A repeater can be used to improve wireless coverage in an area where the Wi-Fi signal is weak.
K. BRIDGE
A bridge is a networking device that connects two network segments and controls the movement of data between them.
A bridge can examine hardware addresses and decide whether traffic should be forwarded between network segments.
FUNCTIONS OF A BRIDGE
1. Connects network segments.
2. Controls the movement of frames between segments.
3. Helps reduce unnecessary network traffic.
4. Separates parts of a network.
Many functions traditionally performed by bridges are now commonly provided by network switches.
L. GATEWAY
A gateway is a device or system that acts as an entry and exit point between different networks or systems.
In an IP network, the default gateway is usually the device through which a computer sends traffic destined for another network.
FUNCTIONS OF A GATEWAY
1. Connects different networks or systems.
2. Provides a route out of a local network.
3. Allows communication between networks using different technologies or protocols in appropriate situations.
4. Acts as an entry and exit point for network traffic.
M. FIREWALL
A firewall is a hardware or software security system that monitors and controls network traffic according to defined security rules.
A firewall helps protect computers and networks from unauthorized network access.
FUNCTIONS OF A FIREWALL
1. Monitors network traffic.
2. Controls incoming and outgoing connections.
3. Blocks unauthorized traffic.
4. Helps protect networks from certain network-based threats.
5. Enforces network security rules.
Firewalls can be implemented in:
- Computers
- Routers
- Servers
- Dedicated network security devices
N. WIRELESS ROUTER
A wireless router is a device that combines routing with wireless networking.
Many home and school networking devices combine several functions, including:
- Router
- Wireless access point
- Ethernet switch
- DHCP service
- NAT
- Basic firewall functions
This allows several devices to connect to one network and, where Internet service is available, access the Internet.
O. NETWORK CABLES
Network cables are used to transmit data between network devices.
Common Network Cable
Ethernet cable is widely used in wired computer networks.
Common categories include:
- Cat5e
- Cat6
- Cat6a
These cables normally use an 8P8C modular connector, commonly called an RJ45 connector in everyday networking terminology.
Uses of Network Cables
They may be used to connect:
1. Computer to switch
2. Router to switch
3. Computer to router
4. Access point to switch
5. Network devices to patch panels
P. COMPARISON OF HUB, SWITCH AND ROUTER
Device Main Function Common Use
Hub Sends received data to connected ports| Older/simple networks
Switch Connects devices and forwards traffic appropriately LAN
Router Connects different networks and directs packets| LAN to Internet/WAN
Important Difference
A hub mainly repeats traffic to its ports.
A switch forwards network traffic within a LAN based on destination information.
A router connects different networks and determines where packets should be sent.
Q. DIFFERENCE BETWEEN A MODEM AND A ROUTER
Modem Router
Provides communication with a Connects and manages communication
Telecommunication service between networks
Converts/handles signals required Directs IP packets between
by the networks access technology
May provide Internet access depending Distributes network connectivity to
on service devices
Usually connects toward the service| Usually connects the local network to the
provider modem/service
Some modern devices combine both functions.
R. IMPORTANCE OF NETWORKING DEVICES
Networking devices are important because they:
1. Connect computers and other devices.
2. Allow sharing of files and resources.
3. Provide access to the Internet.
4. Improve communication between devices.
5. Help organize network traffic.
6. Extend network coverage.
7. Improve network security.
8. Support wireless communication.
9. Allow different networks to communicate.
10. Make computer networks easier to manage.
S. COMMON NETWORK PROBLEMS
Some common network problems include:
1. No Network Connection
The computer cannot connect to the network.
Possible causes:
- Disconnected cable
- Disabled network adapter
- Faulty switch/router
- Incorrect network settings
2. Slow Internet Connection
The network or Internet connection is unusually slow.
Possible causes:
- Network congestion
- Weak wireless signal
- Faulty equipment
- Too many users
- Service-provider problems
3. Weak Wi-Fi Signal
A wireless device has poor connectivity.
Possible causes:
- Long distance from the access point
- Physical obstacles
- Interference
- Poor access-point placement
4. Cable Failure
A network connection may fail because an Ethernet cable or connector is damaged.
5. IP Address Problems
Incorrect or conflicting IP configuration can prevent devices from communicating properly.
T. BASIC NETWORK TROUBLESHOOTING
When troubleshooting a network problem, a technician should work systematically.
Step 1: Identify the Problem
Determine what is not working.
Step 2: Check Physical Connections
Check:
- Network cables
- Power cables
- Network ports
- Router
- Switch
- Modem
- Wireless access point
Step 3: Check Network Indicators
Look at the status lights on relevant networking equipment.
Step 4: Check Network Settings
Check:
- IP address
- Subnet information
- Default gateway
- DNS settings
- Wi-Fi connection
Step 5: Restart Appropriate Equipment
Where appropriate, restart the affected network device or computer.
Step 6: Test the Connection
Use appropriate network diagnostic tools to determine whether communication has been restored.
Step 7: Replace Faulty Components
If a cable or networking device is confirmed faulty, it may need to be repaired or replaced.
U. CARE AND MAINTENANCE OF NETWORKING DEVICES
Networking equipment should be properly maintained to improve reliability and performance.
Students should observe the following:
1. Keep networking devices clean and dust-free.
2. Keep devices in a well-ventilated location.
3. Avoid blocking ventilation openings.
4. Protect equipment from water and moisture.
5. Avoid bending network cables excessively.
6. Do not pull cables forcefully.
7. Label network cables where necessary.
8. Check cables and connectors regularly.
9. Protect equipment from electrical problems using appropriate power protection.
10. Use strong security settings for wireless networks.
11. Update device firmware when appropriate and safe.
12. Keep unauthorized persons from tampering with network equipment.
13. Back up important network configurations where applicable.
14. Replace damaged cables and connectors.
15. Follow electrical and equipment safety procedures.
V. SIMPLE NETWORK ARRANGEMENT
1. A basic network may be arranged as follows:
Internet Service → Modem/ONT → Router → Switch → Computers
2. Wireless devices may connect through:
Router/Wireless Access Point → Wi-Fi Devices
The exact arrangement depends on the type of Internet service and equipment being used.
SUMMARY
Networking devices are hardware components that help computers and other devices communicate and share resources.
Important networking devices include the NIC, hub, switch, router, modem, wireless access point, repeater, bridge, gateway and firewall.
A NIC allows a device to connect to a network. A hub connects devices and generally repeats traffic to its ports. A switch connects devices in a LAN and forwards traffic appropriately. A router connects different networks and directs packets between them. A modem provides communication with certain telecommunications services. A wireless access point provides Wi-Fi connectivity. A repeater extends signal coverage, while a firewall helps control network traffic for security.
Proper installation, troubleshooting, maintenance and security practices are important for reliable network operation.
Evaluation
OBJECTIVE QUESTIONS
Choose the correct answer from options A–D.
1. Which of the following is a networking device?
A. Keyboard
B. Monitor
C. Router
D. Printer
2. What is the main function of a switch?
A. To print documents
B. To connect devices and forward network traffic
C. To store the operating system
D. To display images
3. Which device is primarily used to connect different networks?
A. Router
B. Keyboard
C. Scanner
D. Speaker
4. NIC stands for ________.
A. Network Interface Card
B. Network Internet
Computer
C. New Internet Connection
D. Network Internal Cable
5. Which device provides wireless network connectivity to devices?
A. Wireless Access Point
B. Printer
C. CPU
D. Hard disk
6. Which networking device receives and retransmits signals to extend network coverage?
A. Repeater
B. Monitor
C. Scanner
D. Keyboard
7. Which device generally sends received network traffic to all its connected ports?
A. Router
B. Switch
C. Hub
D. Gateway
8. What is one major purpose of a firewall?
A. To increase screen brightness
B. To filter and control network traffic
C. To store computer files
D. To print documents
9. Which device can provide a connection between a local network and an Internet service?
A. Router
B. Keyboard
C. Mouse
D. Scanner
10. Which of the following is commonly used for wired Ethernet networking?
A. Ethernet cable
B. HDMI cable only
C. Power button
D. Audio cable
THEORY QUESTIONS
1a. What is a computer network? State five importance of computer networks.
1b. Define a networking device and explain the functions of any five networking devices.
2a. Differentiate between a hub, switch and router.
2b. Explain the functions of a modem, Wireless Access Point (WAP) and Network Interface Card (NIC).
2c. State five common network problems and explain the basic steps that can be followed when troubleshooting them.