Introduces the fundamental concepts, purpose and applications of computer networks.
Explores different network classifications based on geographical coverage, purpose and architecture.
Introduces different physical and logical network structures and how network devices are organised.
Provides practical knowledge of the hardware used to build and connect computer networks.
Introduces the physical and wireless technologies used to transmit data across networks
Explains how network communication is structured using standard models and protocols.
Introduces Ethernet technology and the role of MAC addresses in local network communication
Develops practical understanding of IPv4 addressing and network identification
Teaches learners how to divide networks into smaller subnets and introduces IPv6 addressing.
Introduces network switching and provides practical skills for configuring and managing switches.
Teaches learners how to logically separate networks and carry traffic between network segments.
Introduces routing and explains how routers forward traffic between different networks.
Explores essential network services that support addressing, name resolution and internet connectivity.
Provides practical knowledge of wireless networks and access point configuration.
Introduces fundamental techniques for protecting networks, devices and network traffic.
Develops practical skills for managing, monitoring and troubleshooting computer networks.
Introduces modern networking technologies and the role of networking in cloud and virtualised environments.
Enables learners to apply their networking knowledge by designing, configuring, testing and documenting a complete network solution
Computer networking is one of the most important areas of Information and Communication Technology (ICT). Almost every modern organization depends on computer networks to communicate, share information, access online services, operate business systems and connect users to digital resources.
A computer network allows computers and other digital devices to communicate with one another. These devices may include desktop computers, laptops, smartphones, servers, printers, IP cameras, network storage devices, routers, switches, wireless access points and other Internet-connected devices.
For example, when computers in a school computer laboratory are connected together so that students can access a shared printer, exchange files or access the Internet, they form a computer network.
This lesson introduces the meaning of computer networking and then introduces Ethernet fundamentals, which are essential for understanding wired Local Area Networks (LANs).
The lesson provides a foundation for later topics such as IP addressing, subnetting, switching, routing, VLANs, wireless networking, network security, network administration and Cisco networking.
More lessons, instructor explanations, demonstrations, practical exercises, assignments and assessments will be delivered through the Senior ICT Academy Campus by either a physical instructor or an online instructor.
Senior ICT Academy Campus:
https://campus.seniorictacademy.com/login
By the end of this lesson, the learner should be able to:
Define computer networking.
Explain what a computer network is.
Explain why computers and other devices are connected into networks.
Identify common network devices.
Explain the purpose of a network interface card.
Explain the functions of switches, routers and wireless access points.
Identify common network transmission media.
Explain the difference between wired and wireless networking.
Identify common types of computer networks.
Explain basic network topologies.
Explain resource sharing in a network.
Explain client-server and peer-to-peer networking.
Define bandwidth, latency and throughput.
Explain the importance of network security.
Define Ethernet.
Explain the purpose of Ethernet in computer networks.
Identify common Ethernet cables and connectors.
Explain the basic operation of an Ethernet network.
Explain the role of MAC addresses in Ethernet communication.
Distinguish between a switch and a router.
Identify common Ethernet speeds.
Explain basic Ethernet network installation and troubleshooting.
Computer networking is the process of connecting two or more computers or digital devices so that they can communicate, exchange data and share resources.
In simple terms:
Computer networking means connecting devices together so that they can communicate and work together.
The connected devices may include:
Desktop computers
Laptop computers
Servers
Smartphones
Tablets
Printers
Network storage devices
IP cameras
Routers
Switches
Wireless access points
Smart televisions
Internet of Things devices
A network does not necessarily require the Internet.
For example, ten computers connected together inside a computer laboratory can form a network even when the laboratory has no Internet connection.
The Internet is a very large global network made up of many interconnected networks.
A network is a group of devices or systems connected together so that they can communicate or share resources.
A simple network could look like this:
Computer A → Switch → Computer B
A larger network may look like:
Computers → Switch → Router → Internet
In a wireless network:
Laptop → Wi-Fi Access Point → Switch → Router → Internet
The devices communicate using agreed rules called protocols.
Computers and other devices are connected for several important reasons.
Users can communicate through email, messaging systems, video conferencing and other network applications.
Users can access and share documents, images, videos, databases and other files.
Several computers can use one network printer instead of requiring every computer to have its own printer.
Multiple computers and mobile devices can access the Internet through a shared network connection.
Organizations can provide centralized applications and services to many users.
Important information can be stored on servers where authorized users can access it.
Network users can work together on projects, documents and organizational systems.
Organizations can implement centralized backup systems to protect important data.
A school network may contain:
Administration computers
Teachers' computers
Student computers
Servers
Printers
Wi-Fi access points
CCTV cameras
Network storage
Internet routers
The network allows students and staff to access shared services.
Banks use networks to connect:
Branches
ATMs
Servers
Staff computers
Mobile banking systems
Internet banking systems
Security systems
A bank network enables information to move securely between different systems and locations.
A hospital network can connect:
Doctors' computers
Nurses' computers
Laboratory systems
Pharmacy systems
Patient-record systems
Printers
Servers
Wi-Fi devices
A company with offices in Kampala, Masaka, Mbarara and Gulu may connect the offices through a Wide Area Network.
A modern home may have:
Smartphones
Laptops
Smart TV
Printer
Gaming console
IP cameras
Smart appliances
These devices may connect through a wireless router.
A computer network consists of several components.
End devices are devices used by users or systems to send and receive information.
Examples include:
Computers
Laptops
Smartphones
Tablets
Servers
Printers
IP cameras
A Network Interface Card (NIC) allows a device to connect to a network.
A NIC may support:
Ethernet connections
Wi-Fi connections
Fibre or other specialized interfaces
Most modern computers have a built-in network interface.
A network switch connects multiple devices within a LAN.
For example:
Computer 1
Computer 2
Computer 3
Computer 4
can all connect to a switch.
The switch receives Ethernet frames and forwards them toward the appropriate destination.
A router connects different networks.
For example:
LAN → Router → Internet
A router examines network information and determines where packets should be forwarded.
Many modern routers may also provide services such as:
DHCP
NAT
Firewall functions
VPN
Wireless networking
Routing
A wireless access point allows wireless devices to connect to a network.
Example:
Laptop → Wi-Fi → Access Point → Switch → Router
A server provides services to other computers.
Examples include:
File server
Web server
Database server
DNS server
DHCP server
Email server
Application server
Authentication server
Network data must travel through a communication medium.
The main categories are wired and wireless media.
Common Ethernet copper cables include:
Cat5e
Cat6
Cat6A
Copper Ethernet cables are widely used in offices, schools, homes and computer laboratories.
Fibre-optic cables transmit information using light.
They are suitable for:
Long-distance communication
High-speed networks
Internet service providers
Data centres
Network backbones
Wireless networks transmit information using radio signals.
Examples include:
Wi-Fi
Bluetooth
Cellular networks
Data communication is the transfer of information from one device to another.
A basic communication process involves:
Sender
Message or data
Communication medium
Receiver
Communication protocols
For example:
Computer A → Network → Computer B
Computer A sends information, the network carries it, and Computer B receives it.
A protocol is a set of rules used by network devices to communicate.
Important protocols include:
TCP/IP is the fundamental protocol suite used on modern computer networks and the Internet.
HTTP is used for communication between web browsers and web servers.
HTTPS provides encrypted communication for websites using TLS.
DNS translates domain names into IP addresses and supports other name-related functions.
For example:
www.example.com → IP address
DHCP automatically provides network configuration information such as:
IP address
Subnet mask
Default gateway
DNS server
ICMP is used for network diagnostic and control purposes.
The ping command commonly uses ICMP to test reachability.
An IP address is a logical address used at the Internet Protocol layer to identify a network interface and support communication across networks.
An IPv4 address may look like:
192.168.1.10
Another example is:
10.0.0.25
IPv4 uses 32-bit addresses.
IPv6 uses a much larger address space.
Example:
2001:db8::1
Later lessons will cover:
IPv4 addressing
IPv6 addressing
Subnet masks
Default gateways
Private addresses
Public addresses
Static addressing
Dynamic addressing
CIDR
Subnetting
A PAN covers a small area around an individual.
Example:
Smartphone → Bluetooth → Wireless Earbuds
A LAN connects devices within a limited geographical area.
Examples include:
Home
Office
School
Computer laboratory
A WLAN is a LAN that uses wireless communication.
Wi-Fi networks are common examples.
A MAN covers a larger geographical area, often around a city or metropolitan region.
A WAN connects networks across large geographical areas.
Organizations with branches in different cities or countries may use WAN technologies.
The Internet is a global system of interconnected networks.
Wired networking uses physical cables to connect devices.
Ethernet is the most common technology used for wired LANs.
Advantages include:
Reliable communication
Stable connections
High performance
Lower susceptibility to radio interference
Suitable for fixed devices
Easier to control physically
Disadvantages include:
Requires cables
Installation may require additional infrastructure
Less convenient for mobile devices
Cable damage can affect connectivity
Wireless networking allows devices to communicate without a physical network cable between the device and access point.
Examples include:
Wi-Fi
Bluetooth
Cellular networks
Advantages include:
Mobility
Convenience
Easy connection of mobile devices
Reduced cabling
Challenges include:
Radio interference
Limited coverage
Obstacles
Security risks
Signal strength problems
Network topology describes how devices are arranged and connected.
In a star topology, devices connect to a central device, normally a switch.
Example:
Computer → Switch ← Computer
This is one of the most common arrangements in modern Ethernet LANs.
Devices share a common communication backbone.
Bus networks were more common in older networking environments.
Devices are arranged in a circular structure.
Each device is connected to another device in the ring.
Devices have multiple connections between them.
Mesh designs can provide redundancy but may require more infrastructure.
A hybrid topology combines two or more topology designs.
One major purpose of networking is resource sharing.
Resources may include:
Printers
Scanners
Storage devices
Servers
Business applications
Databases
Network applications
Documents
Reports
Images
Databases
Multiple users can share one Internet connection through network infrastructure.
In client-server networking, one system provides services while other systems request those services.
Example:
Client → Request → Server
Server → Response → Client
For example, an employee's computer may request a document from a file server.
A web browser may request a webpage from a web server.
Client-server networks are common in schools, banks, businesses and government institutions.
In a peer-to-peer network, computers can communicate directly and may share resources with each other without depending on a dedicated central server.
Example:
Computer A ↔ Computer B ↔ Computer C
Peer-to-peer networks can be useful in small environments, although larger organizations often prefer centralized client-server architectures because they provide better management and security.
Bandwidth refers to the capacity of a communication link to carry data.
It is commonly measured in:
Bits per second (bps)
Kilobits per second (Kbps)
Megabits per second (Mbps)
Gigabits per second (Gbps)
For example:
100 Mbps
represents a connection capacity of 100 megabits per second.
Bandwidth does not always equal the actual speed experienced by a user.
Latency is the delay experienced when data travels from one point to another.
Low latency is important for:
Video conferencing
Online gaming
Voice communication
Remote systems
Interactive applications
High latency can make applications feel slow even when bandwidth is high.
Throughput is the actual amount of data successfully transferred through a network over a given period.
For example, a network link may have a theoretical capacity of 1 Gbps but provide a lower actual throughput because of congestion, device limitations, interference or protocol overhead.
Ethernet is a family of networking technologies used primarily for wired local area networks.
Ethernet defines important aspects of communication, including how devices transmit data over a physical medium and how Ethernet frames are structured.
Ethernet is widely used in:
Homes
Offices
Schools
Computer laboratories
Data centres
Enterprises
Server rooms
The IEEE 802.3 family of standards is associated with Ethernet.
Ethernet provides a common method for devices to communicate over a wired network.
A basic Ethernet connection may look like:
Computer → Ethernet Cable → Switch
Several computers can connect to the same switch:
Computer 1 ─┐
Computer 2 ─┤
Computer 3 ─┼→ Ethernet Switch
Computer 4 ─┘
The switch then forwards Ethernet frames between connected devices.
Ethernet networks commonly use twisted-pair copper cables.
Examples include:
Cat5e
Cat6
Cat6A
These cables contain pairs of twisted copper wires designed to reduce interference.
The cable normally connects to an Ethernet port using an RJ45-style modular connector.
A typical connection is:
Computer Ethernet Port → Ethernet Cable → Switch Port
An Ethernet port is a physical interface used to connect a device to an Ethernet network.
A computer may have one Ethernet port.
A network switch may have:
5 ports
8 ports
16 ports
24 ports
48 ports
More ports in enterprise equipment
Each port provides a physical connection to another network device.
Ethernet devices use MAC addresses at the data-link layer.
MAC stands for Media Access Control.
A MAC address is normally associated with a network interface.
A simplified example is:
00:1A:2B:3C:4D:5E
MAC addresses are used by Ethernet switches to make forwarding decisions within a LAN.
An important distinction is:
MAC address = Layer 2 identification
IP address = Layer 3 logical addressing
This distinction becomes very important when studying switching and routing.
Ethernet communicates using frames.
An Ethernet frame contains important information such as:
Destination MAC address
Source MAC address
Type/length information
Payload
Error-detection information
The frame is transmitted across the Ethernet network.
A switch examines relevant frame information and forwards the frame toward its destination.
A switch can build a MAC address table by examining the source MAC addresses of frames arriving on its ports.
For example:
Port 1 → Computer A MAC address
Port 2 → Computer B MAC address
Port 3 → Computer C MAC address
When the switch receives a frame destined for Computer B, it can use its MAC address table to determine the appropriate port.
This improves network efficiency because the switch does not need to send every frame to every port.
A switch and router perform different primary functions.
A switch primarily connects devices within a LAN and forwards Ethernet frames using Layer 2 information such as MAC addresses.
A router connects different IP networks and forwards packets based on Layer 3 information such as IP addresses.
Example:
Computers → Switch → Router → Internet
The switch provides local connectivity while the router provides connectivity between different networks.
Ethernet has developed through many generations.
Common examples include:
10 Mbps Ethernet
100 Mbps Fast Ethernet
1 Gbps Gigabit Ethernet
2.5 Gbps Ethernet
5 Gbps Ethernet
10 Gbps Ethernet
Higher-speed Ethernet technologies
The actual speed available depends on the network interface, cable, switch, configuration and standard being used.
Ethernet communication can operate in different modes.
A device can transmit or receive, but not both simultaneously.
A device can transmit and receive simultaneously.
Modern switched Ethernet networks commonly operate using full-duplex communication.
A simple office Ethernet network can be designed as:
PC 1 ─┐
PC 2 ─┤
PC 3 ─┤
PC 4 ─┼→ Switch → Router → Internet
Printer ─┘
The switch provides communication between local devices.
The router provides connectivity to other networks, including the Internet.
Suppose a computer laboratory has:
20 computers
1 network printer
1 server
2 Ethernet switches
1 router
2 wireless access points
The computers can connect to the switches using Ethernet cables.
The switches connect to the router.
The router connects the laboratory network to the Internet.
The wireless access points can connect laptops and smartphones to the same network.
The network can provide:
Internet access
File sharing
Printer sharing
Server access
Online learning
Internal communication
When installing an Ethernet network, the technician should consider:
Number of devices.
Location of devices.
Required cable lengths.
Cable category.
Switch capacity.
Router requirements.
Power availability.
Cable management.
Network security.
Future expansion.
Proper installation reduces network problems and makes troubleshooting easier.
When an Ethernet connection does not work, check the following:
Ensure the cable is properly connected at both ends.
Look at the Ethernet port and switch port.
A link indicator may show whether a physical connection has been established.
The cable may be damaged.
The switch port may have a problem.
Make sure the computer's network interface is enabled.
Use appropriate operating-system commands to inspect the IP configuration.
The ping command can be used to test connectivity to another device.
If local communication works but Internet access does not, inspect the router, gateway and Internet connection.
Computer networks must be protected against unauthorized access, attacks and data loss.
Common threats include:
Malware
Phishing
Unauthorized access
Password attacks
Denial-of-service attacks
Data interception
Unpatched systems
Rogue devices
Basic security measures include:
Strong passwords
Multi-factor authentication
Firewalls
Secure Wi-Fi configuration
Encryption
Regular software updates
Access control
Network segmentation
Backups
Monitoring
User security awareness
Computer networking provides many benefits.
File sharing
Printer sharing
Internet sharing
Faster communication
Centralized management
Remote access
Collaboration
Centralized storage
Centralized backup
Better resource utilization
Support for cloud services
Improved organizational productivity
Networking also introduces challenges.
These include:
Installation costs
Maintenance costs
Security threats
Hardware failures
Cable damage
Configuration errors
Network congestion
Troubleshooting complexity
Unauthorized access
Dependence on network infrastructure
Proper planning, administration and security can reduce these challenges.
Learners should examine the network environment around them.
Identify:
Five network devices.
Which devices use Ethernet?
Which devices use Wi-Fi?
The router.
The network switch.
Wireless access points.
Computers and mobile devices.
Shared resources.
Possible network security risks.
The Internet connection.
Possible points of network failure.
Discuss the following questions:
What happens if the router stops working?
What happens if the switch stops working?
Which users will lose access to the network?
Can users still communicate locally if the Internet is unavailable?
Design a network for a computer laboratory containing:
10 computers
1 printer
1 server
1 switch
1 router
1 wireless access point
The learner should:
Draw the network topology.
Connect the computers to the switch.
Connect the printer to the network.
Connect the server to the switch.
Connect the switch to the router.
Connect the access point to the network.
Explain how wireless users access the network.
Explain how the printer is shared.
Explain how the server provides services.
Identify at least five security measures.
Answer the following questions:
What is computer networking?
What is a computer network?
Why are computers connected into networks?
What is resource sharing?
What is a network protocol?
What is an IP address?
What is the function of a network switch?
What is the function of a router?
What is a wireless access point?
What is a server?
What is a LAN?
What is a WAN?
What is a PAN?
What is a WLAN?
What is the difference between wired and wireless networking?
What is network topology?
Name five network topologies.
Name five network devices.
State five advantages of computer networking.
State five challenges of computer networking.
What is bandwidth?
What is latency?
What is throughput?
What is Ethernet?
Which IEEE standard family is associated with Ethernet?
What is a MAC address?
What is the difference between a MAC address and an IP address?
What is an Ethernet frame?
What is the purpose of an Ethernet switch?
What is the difference between a switch and a router?
Name three common Ethernet cable categories.
What is full-duplex communication?
What is the purpose of an Ethernet port?
Why is cable quality important in an Ethernet network?
Give five basic Ethernet troubleshooting steps.
Design a computer network for an organization with:
10 desktop computers
5 laptops
1 server
2 network printers
2 wireless access points
1 router
1 network switch
Your assignment should include:
A network diagram.
The selected topology.
The type of cables required.
The role of the switch.
The role of the router.
The role of the server.
The role of the wireless access points.
How printers will be shared.
How users will access the Internet.
At least five network security measures.
At least five possible network problems.
Proposed solutions for those problems.
Computer Network – A group of connected devices that communicate and share resources.
Networking – The process of connecting devices for communication and resource sharing.
LAN – Local Area Network.
WAN – Wide Area Network.
WLAN – Wireless Local Area Network.
Ethernet – A family of technologies commonly used for wired LAN communication.
Switch – A device that primarily connects devices within a LAN and forwards Ethernet frames.
Router – A device that connects different networks and forwards IP packets.
NIC – Network Interface Card.
MAC Address – An address associated with a network interface at the data-link layer.
IP Address – A logical address used for IP communication.
Protocol – A set of rules governing communication.
Bandwidth – The capacity of a communication link.
Latency – The delay experienced during communication.
Throughput – The actual rate of successful data transfer.
This lesson provides the foundation for computer networking, but it is only the beginning of the networking course.
More detailed lessons, instructor explanations, demonstrations, practical exercises, assignments and assessments will be delivered through the Senior ICT Academy Campus.
Learning may be delivered by either:
A physical instructor can provide:
Face-to-face explanations
Practical demonstrations
Network equipment configuration
Cable installation exercises
Switch and router demonstrations
Troubleshooting exercises
Laboratory practice
Learner support
An online instructor can provide:
Live online lessons
Recorded explanations
Screen demonstrations
Network configuration demonstrations
Assignments
Online assessments
Discussion and learner support
Senior ICT Academy Campus:
https://campus.seniorictacademy.com/login
Future lessons will include:
Introduction to the OSI Model
TCP/IP Model
Ethernet in greater detail
MAC addresses
IPv4 addressing
IPv6 addressing
Subnet masks
Default gateways
CIDR
Subnetting
DHCP
DNS
Switching
Routing
VLANs
Trunking
Wireless networking
Network troubleshooting
Network security
Network administration
Cisco networking
Practical network configuration
Computer networking is the process of connecting computers and other digital devices so that they can communicate and share resources.
Networks can be small, such as a home network, or very large, such as the Internet.
Important network components include computers, servers, NICs, switches, routers, wireless access points and transmission media.
Ethernet is one of the most important technologies used for wired LANs. Ethernet uses frames and MAC addresses for local network communication, while IP addresses support communication at the network layer.
Understanding networking and Ethernet provides the foundation for more advanced areas such as switching, routing, IP addressing, subnetting, VLANs, wireless networking, network security and network administration.