Wired and Wireless Networks

This section provides an overview of wired and wireless networks, focusing on encryption, addressing protocols, and the importance of network layering for a modular, secure, and efficient network design.

Wired and Wireless Networks

Wired Networks: Use physical cables (e.g., Ethernet) to connect devices.

Advantages: More stable and secure than wireless, with typically faster data transfer speeds and less interference.

Disadvantages: Limited by physical connections, which can be restrictive and costly to install and maintain.

Wireless Networks: Connect devices using radio waves, allowing mobility and flexibility.

Advantages: Easier to set up, allowing devices to connect without physical cables, ideal for portable devices.

Disadvantages: Prone to interference and security risks, often slower and less reliable than wired networks.

Bluetooth

A wireless technology for short-range communication between devices (up to around 10 metres).

Use Cases: Commonly used for connecting peripheral devices like keyboards, headphones, and transferring files between nearby devices.

Advantages: Low power, convenient for connecting devices without needing cables.

Limitations: Limited range, slower data transfer compared to Wi-Fi, and less secure for sensitive data.

Encryption

Definition: Encryption is the process of converting data into a coded format to prevent unauthorised access. Only authorised users with the correct decryption key can access the original data.

Asymmetric Encryption (Public and Private Keys)

Uses two different keys for encryption and decryption: a public key (known to everyone) and a private key (kept secret by the owner).

Process: Data is encrypted with the recipient’s public key and can only be decrypted by the corresponding private key. This is commonly used in secure communication (e.g., HTTPS websites).

Advantages: Provides secure data transfer even if the public key is widely available.

Encryption in Use

Encryption is essential for secure online transactions, email communications, and safeguarding sensitive data.

Examples include secure website connections (HTTPS), email encryption, and encryption of personal files and databases.

Addressing and Protocols

IP Addressing

Internet Protocol (IP) Address: A unique identifier for each device on a network, enabling devices to communicate over the internet or within a local network.

Types: IPv4 (32-bit, e.g., 192.168.0.1) and IPv6 (128-bit, for a larger address space).

MAC Addressing

Media Access Control (MAC) Address: A unique 48-bit identifier assigned to a network interface card (NIC) for communication on the local network.

Use: Primarily used within LANs to identify devices; cannot be changed and is unique to each device’s hardware.

Other Protocols

HTTP/HTTPS: Protocols for transferring web pages. HTTPS includes encryption for secure browsing.

FTP (File Transfer Protocol): Used for transferring files between computers over a network.

SMTP (Simple Mail Transfer Protocol): Used for sending emails.

TCP/IP (Transmission Control Protocol/Internet Protocol): Manages data transmission over the internet, ensuring data packets are delivered accurately.

POP3/IMAP: Protocols used for receiving emails, with IMAP allowing remote storage and POP3 downloading emails to a device.

Network Layering

Definition: Network layering is a design model that divides networking tasks into layers, with each layer responsible for specific functions. Each layer interacts only with the layer directly above or below it, simplifying network design and troubleshooting.

OSI Model (Open Systems Interconnection)

Layer 1 – Physical Layer: Handles the physical connection between devices (e.g., cables, signals).

Layer 2 – Data Link Layer: Ensures reliable data transfer over a physical link, managing MAC addresses.

Layer 3 – Network Layer: Manages IP addressing and routing of data packets across networks.

Layer 4 – Transport Layer: Ensures complete data transfer and error-checking (e.g., TCP).

Layer 5-7: Additional layers (Session, Presentation, Application) are used in complex network models for application-level processing, data formatting, and session management.

Benefits of Network Layering

Modularity: Layers are designed to be independent, making it easier to update or troubleshoot specific network functions.

Interoperability: Allows different hardware and software to communicate effectively, as each layer follows standardised protocols.

Simplicity: Breaking down the networking process into manageable layers makes it easier to understand, design, and manage networks.