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Wired & Wireless Networks, Protocols and Layers

How devices connect and communicate using standards and rules

What You'll Learn

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Connection Types

Compare wired (Ethernet) and wireless (WiFi, Bluetooth) connections

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Encryption

Understand how data is secured across network connections

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Addressing

Learn about IP addresses (IPv4/IPv6) and MAC addresses

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Protocols

Understand common protocols: TCP/IP, HTTP, HTTPS, FTP, email protocols

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Layers

Learn how layers organise network communication

1. Wired vs Wireless Connections

Devices can connect to networks in two main ways: using physical cables (wired) or using radio signals (wireless). Each method has advantages and disadvantages.

Wired Connections: Ethernet

Ethernet is the most common wired networking technology. It uses cables (usually Cat5e or Cat6) to connect devices directly to network switches or routers.

Ethernet Characteristics

  • Speed: Very fast - typically 1 Gbps, up to 10 Gbps
  • Reliability: Stable connection with minimal interference
  • Security: More secure - requires physical access to tap
  • Mobility: Devices must stay connected to the cable

Wireless Connections

WiFi

Wireless networking for local area networks. Uses radio waves to connect devices to a wireless access point.

  • Range: Typically 30-50 metres indoors
  • Speed: Up to several Gbps (WiFi 6)
  • Use: Laptops, phones, tablets, IoT devices

Bluetooth

Short-range wireless technology for connecting personal devices.

  • Range: Typically up to 10 metres
  • Speed: Up to 3 Mbps
  • Use: Headphones, keyboards, mice, speakers

Wired vs Wireless Comparison

Factor Wired (Ethernet) Wireless (WiFi)
Speed Faster, more consistent Slower, varies with distance
Reliability Very reliable, no interference Can be affected by walls, other devices
Security More secure (physical access needed) Signals can be intercepted
Mobility Devices are fixed in place Users can move freely
Installation Requires running cables Easy to set up, no cables
Cost Cable installation can be expensive Lower installation cost
Choosing a Connection: Use wired connections for devices that need speed and reliability (gaming PCs, servers, office desktops). Use wireless for mobile devices and convenience.

2. Encryption

Encryption is the process of converting data into a coded format that can only be read by someone with the correct key. It's essential for securing data transmitted across networks.

Why Encryption Matters

When data travels across a network, it could potentially be intercepted. Encryption ensures that even if data is captured, it cannot be read without the decryption key.

Original Data "Password123"
→ Encrypt →
Encrypted Data "X7#kL9@mQ2..."
→ Decrypt →
Original Data "Password123"

Where Encryption is Used

  • WiFi networks: WPA2/WPA3 encryption protects wireless traffic
  • Websites: HTTPS uses encryption (the padlock icon in your browser)
  • Email: Many email services encrypt messages in transit
  • Online banking: All financial transactions are encrypted
  • VPNs: Virtual Private Networks encrypt all your internet traffic
Security Note: Always look for the padlock icon (🔒) in your browser when entering sensitive information. This indicates the connection is encrypted using HTTPS.

3. IP Addressing and MAC Addressing

Every device on a network needs addresses to send and receive data. There are two main types of addresses: IP addresses and MAC addresses.

IP Addresses

An IP (Internet Protocol) address is a logical address assigned to a device on a network. It identifies where to send data across networks.

IPv4 (Internet Protocol version 4)

The older and more common format.

  • Format: Four numbers separated by dots
  • Range: Each number is 0-255
  • Example: 192.168.1.100
  • Total addresses: About 4.3 billion
192.168.1.100

Each section uses 8 bits (1 byte), total = 32 bits

IPv6 (Internet Protocol version 6)

The newer format with more addresses.

  • Format: Eight groups of hexadecimal, separated by colons
  • Example: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
  • Total addresses: 340 undecillion (340 trillion trillion trillion)
2001:0db8:85a3::8a2e:0370:7334

128 bits total - enough for every grain of sand on Earth!

Why IPv6? IPv4 addresses are running out! With billions of devices connecting to the internet (phones, computers, IoT devices), we need the much larger address space that IPv6 provides.

MAC Addresses

A MAC (Media Access Control) address is a physical address permanently assigned to a device's network interface card (NIC) by the manufacturer.

MAC Address Characteristics

  • Format: Six pairs of hexadecimal digits, separated by colons or hyphens
  • Example: 00:1A:2B:3C:4D:5E or 00-1A-2B-3C-4D-5E
  • Uniqueness: Every NIC has a unique MAC address worldwide
  • Permanent: Set by the manufacturer, doesn't change
00:1A:2B:3C:4D:5E
00:1A:2B Manufacturer ID (OUI) 3C:4D:5E Device ID

IP vs MAC Addresses

Aspect IP Address MAC Address
Type Logical (software-assigned) Physical (hardware-assigned)
Can change? Yes - can be reassigned No - permanently set by manufacturer
Used for Routing data between networks Identifying devices within a local network
Scope Global (internet-wide) Local (within same network)
Analogy: Think of a MAC address like your name (permanent, given at birth) and an IP address like your postal address (can change when you move house).

4. Standards

A standard is a set of agreed rules or specifications that ensure hardware and software from different manufacturers can work together.

Why Standards Matter

Without standards, devices from different companies wouldn't be able to communicate. Imagine if every phone manufacturer used their own unique charging port!

🔌 USB Standard

Allows any USB device to connect to any USB port

📶 WiFi Standards

Any WiFi device can connect to any WiFi router

🌐 HTML Standard

Web pages work in any browser

📁 File Format Standards

JPEG images open in any image viewer

Benefits of Standards

  • Interoperability: Devices from different manufacturers work together
  • Competition: Multiple companies can make compatible products, reducing prices
  • Consumer choice: Users aren't locked into one manufacturer
  • Innovation: Companies can focus on improving products rather than reinventing basics
  • Reliability: Tested, proven specifications reduce errors
Who Creates Standards? Standards are created by organisations like IEEE (Institute of Electrical and Electronics Engineers), ISO (International Organization for Standardization), and W3C (World Wide Web Consortium).

5. Communication Protocols

A protocol is a set of rules that govern how data is transmitted between devices. Different protocols are designed for different purposes.

TCP/IP

Transmission Control Protocol / Internet Protocol

Purpose: The fundamental protocols of the internet. Controls how data is packaged, addressed, transmitted, routed, and received.

Key features:

  • Breaks data into packets
  • Ensures reliable delivery (checks all packets arrive)
  • Handles addressing and routing

HTTP

Hypertext Transfer Protocol

Purpose: Transfers web pages from servers to browsers.

Key features:

  • Request-response model
  • Transfers HTML, images, videos
  • Stateless (each request is independent)

URLs starting with http://

HTTPS

Hypertext Transfer Protocol Secure

Purpose: Secure version of HTTP - encrypts web traffic.

Key features:

  • All data is encrypted
  • Verifies website identity
  • Protects sensitive information

🔒 URLs starting with https://

FTP

File Transfer Protocol

Purpose: Transfer files between computers over a network.

Key features:

  • Upload and download files
  • Navigate remote directories
  • Used for website deployment

Email Protocols

Email uses three different protocols, each with a specific purpose:

POP3 vs IMAP: Use POP3 if you only check email on one device. Use IMAP if you want to access emails from multiple devices (phone, laptop, tablet) - your emails stay synchronised.

Protocol Summary

Protocol Purpose Common Use
TCP/IP Core internet communication All internet traffic
HTTP Transfer web pages Browsing websites
HTTPS Secure web page transfer Online banking, shopping, login pages
FTP Transfer files Uploading website files to a server
SMTP Send emails Outgoing email
POP3 Download emails (single device) Email on one computer
IMAP Sync emails (multiple devices) Email on phone, laptop, tablet

6. The Concept of Layers

Network communication is organised into layers. Each layer handles a specific aspect of communication and passes data to the next layer.

Why Use Layers?

Breaking network communication into layers provides several benefits:

  • Modularity: Each layer can be developed and updated independently
  • Simplicity: Complex processes are broken into manageable parts
  • Standardisation: Layers define clear interfaces between components
  • Interoperability: Different manufacturers can create compatible products for each layer
  • Troubleshooting: Problems can be isolated to specific layers

The TCP/IP Model (4 Layers)

The TCP/IP model is the most commonly used layered model for internet communication:

4

Application Layer

Provides network services to applications

HTTP, HTTPS, FTP, SMTP, POP3, IMAP

↓ Data passed down ↓
3

Transport Layer

Ensures reliable data transfer between hosts

TCP, UDP

↓ Data passed down ↓
2

Internet Layer

Handles addressing and routing across networks

IP (IPv4, IPv6)

↓ Data passed down ↓
1

Network Access Layer

Handles physical transmission of data

Ethernet, WiFi, hardware

How Layers Work Together

Analogy: Sending a Letter

Think of layers like sending a letter through the postal system:

  1. Application Layer: You write the letter content
  2. Transport Layer: You put it in an envelope with a return address
  3. Internet Layer: The postal service reads the address and routes it
  4. Network Access Layer: The van physically delivers the letter

Each layer adds its own information (like addressing) and handles its own responsibility.

Encapsulation: As data passes down through layers, each layer adds its own header information. When received, the data passes back up through layers, with each layer removing its header.

Practice Activities

Apply what you've learned with these interactive exercises:

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Predict

Predict which protocols and connections to use in different scenarios

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Worked Examples

Study detailed examples of protocol usage and addressing

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Step-by-Step

Trace through network processes step by step

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Parsons Problems

Arrange steps in the correct order

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Knowledge Check

Test your understanding with a quiz

Key Terms

Ethernet
Wired networking technology using cables for reliable, fast connections
WiFi
Wireless networking technology using radio waves
Bluetooth
Short-range wireless technology for personal device connections
Encryption
Converting data into a coded format for security
IP Address
Logical address assigned to a device for network routing
MAC Address
Permanent physical address assigned to a NIC by the manufacturer
Standard
Agreed rules that allow hardware/software from different manufacturers to work together
Protocol
A set of rules for transmitting data between devices
TCP/IP
The fundamental protocols of the internet
Layers
Organised levels that each handle different aspects of network communication