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
1. Lesson Introduction
Computers connected to a network need a way to communicate and share resources. Different network architectures determine how computers provide and use services.
Two common approaches are:
Client-server networking
Peer-to-peer networking
In a client-server network, one or more dedicated computers called servers provide services or resources to other computers called clients.
In a peer-to-peer network, computers can communicate directly and share resources with one another without requiring a dedicated central server for every service.
Understanding these two architectures helps network administrators choose an appropriate design for homes, schools, businesses, training institutions, banks, and other organizations.
By the end of this lesson, the learner should be able to:
Define a client-server network.
Define a peer-to-peer network.
Explain the difference between clients and servers.
Explain how client-server communication works.
Explain how peer-to-peer communication works.
Identify common client-server services.
Identify situations where peer-to-peer networking can be useful.
Compare client-server and peer-to-peer networks.
Explain the advantages and disadvantages of each architecture.
Select an appropriate architecture for a given organization.
Design a simple client-server network.
Design a simple peer-to-peer network.
Network architecture describes how computers, devices, services, and resources are organized and how they communicate.
It helps answer questions such as:
Which computer provides a service?
Which computers request services?
Where are files stored?
Who manages user accounts?
Who controls access?
How are resources shared?
Two basic architectures are client-server and peer-to-peer.
A client-server network is a network architecture in which dedicated servers provide services or resources to client devices.
The client requests a service, while the server processes the request and provides the appropriate response.
For example:
A student uses a computer to access an online learning system.
Student computer → Request → Web server
Web server → Response → Student computer
The student computer acts as the client, while the server provides the service.
A client is a device or software application that requests or uses a service provided by another computer or system.
Examples of clients include:
Desktop computers
Laptops
Smartphones
Tablets
Thin clients
Web browsers
Email applications
Mobile applications
For example, when a learner opens a website using a web browser, the browser acts as a client requesting information from a web server.
A server is a computer system or software service that provides resources or services to other devices.
Servers can provide:
Websites
Files
Databases
Authentication
Applications
DNS
DHCP
Printing
Backup services
A server can be a powerful physical computer, a virtual machine, or a cloud-based system.
Provides web pages and web applications to clients.
Examples include websites accessed using a web browser.
Stores and provides access to files.
Example:
A company may store shared documents on a central file server.
Stores and manages structured data.
Examples include student records, customer records, and financial information.
Handles email services such as sending, receiving, and storing email.
Translates domain names into IP addresses.
Example:
A user enters a website name, and DNS helps locate the appropriate server.
Automatically provides network configuration such as IP addresses to clients.
Helps verify user identities and manage access to network resources.
A simplified client-server communication process is:
The client requests a service.
The request travels across the network.
The server receives the request.
The server processes the request.
The server sends a response.
The client receives and uses the response.
Example:
A learner opens a course page.
Computer → Internet → Web server
The web server processes the request and sends the requested page back.
Consider a school with:
50 student computers
10 staff computers
1 file server
1 database server
1 Internet router
Network switches
The servers could provide:
Student records
Shared teaching materials
Authentication
Printing
Database services
The student and staff computers act as clients.
A training institution may have a central learning server.
Students use computers or phones to access:
Course materials
Assignments
Assessments
Student profiles
Learning records
The central server manages the application and data while students access it through client devices.
Banks commonly depend on centralized systems to provide services.
A branch computer may request information from centralized systems such as:
Customer databases
Account services
Transaction processing
Authentication systems
The branch computer acts as a client while centralized systems provide services.
Network administrators can manage resources from centralized systems.
Security policies can be applied consistently.
Important information can be stored centrally and backed up.
Servers can provide shared files, applications, databases, printers, and other services.
User accounts and permissions can be managed centrally.
Client-server networks can support organizations with many users and devices when appropriately designed.
Dedicated servers allow administrators to monitor and maintain important services.
Dedicated servers and server software can increase costs.
Skilled personnel may be required to configure and maintain the environment.
If an important server becomes unavailable, dependent services may be affected.
Clients may depend heavily on network connectivity to access centralized services.
Servers require updates, backups, monitoring, security controls, and maintenance.
A peer-to-peer, or P2P, network is a network architecture where computers can communicate and share resources directly with one another.
There is no requirement for a dedicated central server to manage every shared resource.
Each computer can act as both:
A client
A server
For example:
Computer A shares a printer with Computer B.
Computer B can share a folder with Computer A.
Both computers participate in providing resources.
In a simple peer-to-peer network:
Computer A ↔ Computer B
Computer A ↔ Computer C
Computer B ↔ Computer C
Each computer may provide and consume resources.
A peer can:
Share files
Share folders
Share a printer
Exchange information
Provide certain services
Imagine a small office with five computers.
There is no dedicated file server.
Computer 1 shares a folder containing documents.
Computer 2 shares a printer.
Computer 3 shares another folder.
The computers communicate directly across the local network.
This is a simple peer-to-peer arrangement.
A dedicated server may not be necessary.
Small peer-to-peer networks can be relatively simple to configure.
Users can share files and devices directly.
P2P can be appropriate for a small number of computers with limited requirements.
Every computer can participate in resource sharing.
Managing many computers individually can become difficult.
Permissions may be configured separately on different computers.
Important files may be distributed across many computers.
A computer sharing resources may become slower while providing those resources.
P2P becomes increasingly difficult to manage as the number of computers grows.
Resource availability may depend on whether a particular computer is switched on and connected.
| Feature | Client-Server | Peer-to-Peer |
|---|---|---|
| Dedicated server | Usually yes | Not required |
| Centralized management | Yes | Limited |
| Resource location | Often centralized | Distributed |
| Administration | Centralized | Distributed |
| Cost | Generally higher | Generally lower |
| Security management | Easier centrally | More difficult as network grows |
| Backup | Easier centrally | More difficult |
| Scalability | Generally better | Limited |
| Suitable for | Medium/large organizations | Small networks |
| Server failure impact | Can be significant | No single dedicated server |
| User management | Centralized possible | Usually decentralized |
Some networks combine characteristics of client-server and peer-to-peer architectures.
For example, an organization may have:
Centralized authentication server
Centralized database
Central file server
Computers that also share selected resources directly
Such an environment can use both centralized services and peer resource sharing.
A dedicated server is normally designed to provide services to other systems.
A peer computer can both use services and provide services.
For example:
Server:
Provides → Files
Provides → Database
Provides → Authentication
Peer:
Uses → Shared files
Provides → Shared folder
Uses → Shared printer
Client-server networks make it easier to manage resources centrally.
An administrator may be able to:
Create user accounts
Disable accounts
Assign permissions
Manage shared folders
Monitor servers
Configure backups
Apply security policies
This is especially useful in organizations with many users.
In a peer-to-peer network, resources are distributed among the computers.
For example:
PC 1 → Shared folder
PC 2 → Shared printer
PC 3 → Shared files
PC 4 → Shared media
The administrator may need to configure each computer individually.
Client-server networks can provide stronger centralized security because user authentication, access permissions, logging, and security policies can be managed centrally.
Peer-to-peer networks can still be secured, but maintaining consistent security becomes more difficult as the number of computers increases.
Regardless of architecture, organizations should use:
Strong authentication
Appropriate permissions
Software updates
Endpoint security
Backups
Network security controls
User awareness
In a client-server environment, dedicated servers can be optimized for providing services to many clients.
For example, a server may have:
High-performance processors
Large memory capacity
Fast storage
Redundant power
Multiple network interfaces
In a peer-to-peer environment, a user's computer may need to perform normal user tasks while also sharing resources.
A small peer-to-peer network may be less expensive because it may not require dedicated server hardware.
A client-server network may require:
Server hardware
Server operating systems or services
Backup systems
UPS
Security systems
Professional administration
However, client-server architecture may provide greater control and scalability, making the additional investment worthwhile for larger organizations.
A small home network with a few computers may use peer-to-peer sharing.
A larger institution with many users may benefit from client-server architecture.
Consider:
Number of users
Number of devices
Security requirements
Budget
Data volume
Backup requirements
Administrative requirements
Scalability
Availability requirements
A family has three computers and wants to share:
A printer
Photos
Documents
A simple peer-to-peer network may be sufficient.
Each computer can share selected resources with the others.
A business with 15 employees needs:
Central file storage
User accounts
Shared applications
Central backups
Controlled access
A client-server network may be more appropriate.
A training institution with hundreds of learners may require:
Authentication
Learning management system
Database
File storage
Printing
Internet access
Centralized backups
A client-server architecture is generally more appropriate for these centralized services.
A training environment can use client-server architecture for centralized learning services.
Learners may use:
Desktop computers
Laptops
Smartphones
Tablets
These clients connect to centralized services such as:
Learning platform
Authentication
Course content
Assessment systems
Databases
Additional local resource sharing may also occur within the network.
Clients may be unable to access the service.
Possible causes:
Server failure
Power failure
Network failure
Software problem
Maintenance
The client may not be able to reach the server.
Check:
Cable
Wi-Fi
IP address
Switch
Router
Firewall
DNS
Possible causes:
Incorrect username
Incorrect password
Disabled account
Authentication server unavailable
Too many requests can affect server performance.
Possible solutions include:
Increasing server resources
Load balancing
Optimizing applications
Monitoring resource usage
Check:
Network connectivity
Sharing settings
Permissions
Firewall settings
Check:
Printer power
Network connection
Sharing configuration
Driver installation
A computer providing shared resources may experience increased resource usage.
Check:
User permissions
Passwords
Firewall
Security software
Shared resources
For each scenario, identify whether it is primarily client-server or peer-to-peer.
Five home computers share folders directly.
A school uses a central student database server.
A browser requests a web page from a web server.
Three office computers share files directly without a server.
Employees log into a centralized authentication system.
Explain your answers.
Design a network for five computers.
Requirements:
Share files.
Share one printer.
Share an Internet connection.
No dedicated server.
Identify:
Network devices
Shared resources
Computers acting as peers
Security controls
Design a network for a training centre.
Requirements:
20 client computers
One file server
One database server
One printer server or shared printer
Internet access
Wireless access
Identify:
Clients
Servers
Switch
Router
Access point
Shared resources
Security controls
Create a table comparing client-server and peer-to-peer networks based on:
Cost
Security
Scalability
Administration
Backup
Performance
Resource sharing
Write a recommendation for:
A home.
A small business.
A large school.
Using Cisco Packet Tracer or another networking simulator:
Create a simple client-server network containing:
One switch
One server
Four PCs
Assign IP addresses and test connectivity.
Then create a second network in which the PCs share resources without a dedicated server.
Compare the two designs.
What is a network architecture?
Define a client.
Define a server.
What is a client-server network?
What is a peer-to-peer network?
Give four examples of network servers.
Explain how a client communicates with a server.
Give four advantages of client-server networking.
Give four disadvantages of client-server networking.
Give four advantages of peer-to-peer networking.
Give four disadvantages of peer-to-peer networking.
Differentiate client-server and peer-to-peer networks.
Why is centralized management important?
Why can peer-to-peer networks become difficult to manage?
Which architecture would you recommend for a large school? Explain.
Which architecture could be suitable for a small home network? Explain.
What is a hybrid network architecture?
Explain why backups are generally easier to manage centrally.
Explain the importance of security in both architectures.
Describe one real-world example of a client-server network.
A new computer training centre is planning to connect 40 computers.
The centre needs:
Internet access
Shared learning materials
Student accounts
Staff accounts
Centralized data
Printing
Backups
Security
Prepare a proposal answering:
Would you recommend client-server or peer-to-peer networking?
Why?
What servers would be required?
What network devices would be required?
How would users be authenticated?
How would files be shared?
How would backups be handled?
How would the network be secured?
What would happen if the main server failed?
How could the network be expanded in the future?
Client
Server
Client-server
Peer
Peer-to-peer
Network architecture
File server
Web server
Database server
DNS server
DHCP server
Authentication server
Centralized management
Distributed management
Resource sharing
Shared folder
Shared printer
Hybrid network
Scalability
Network administration
Client-server and peer-to-peer are two important network architectures.
A client-server network uses dedicated servers to provide services to clients. It is particularly useful where centralized management, security, data storage, authentication, backup, and scalability are important.
A peer-to-peer network allows computers to communicate and share resources directly. It can be inexpensive and simple for small networks, but management and security can become more difficult as the network grows.
The most appropriate architecture depends on the organization's:
Size
Budget
Security requirements
Number of users
Data requirements
Management requirements
Future growth