Network Hardware

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Network Hardware

We need a wide variety of different hardware to build an effective network.

Network Interface Controller (NIC)

A NIC provides a connection between the device and the network.
The NIC will take a different form based on the transmission media used. For example:
- The NIC will usually have an RJ45 port for wired networks.
- The NIC will have a radio transmitter/receiver for wireless networks.
Nowadays, most NICs are built directly into the motherboard of a computer.

Switch

A switch connects together several devices to form a wired network.
Each computer on the network has its own unique address, called a Media Access Control (MAC) address.
When data is sent on the network, it includes the sender and recipient address.
The switch learns the MAC addresses of the devices connected to it, so that it can send the data to the intended destination only.

Router

A router is a piece of hardware which connects networks together.
Routers work by inspecting the destination Internet Protocol (IP) address of the data being sent, and determining if it belongs to the local network.
- If the data does not belong to the local network, it will be sent to the connected network.

Wireless Access Point (WAP)

A WAP is a piece of hardware which connects to a switch and allows WiFi devices to connect to the network.
WAPs broadcast an SSID (network name) so that wireless devices know which network to join.
It is important that WAPs use encryption and authentication so that unauthorised individuals do not take advantage of the network.

Transmission Media

Transmission media are different ways of physically transferring data along a network.

Twisted-pair copper cable

This is often referred to as 'Ethernet cable'.
Inside the cable, there are eight wires which are twisted into pairs. This is to reduce interference from other signals and improve transmission speed.
Twisted cables have different ratings to indicate how quickly data can be transferred.
- E.g. Cat-5e can transmit at 1 Gbps.
- E.g. Cat-6 can transmit at 10 Gbps.

Fibre-optic cable

Fibre-optic cables are made of thin strands of glass which transmit binary data as pulses of light.
Fibre-optic cables have many advantages:
- Do not suffer interference.
- Very high bandwidth (100Tbps).
Because of the lack of interference, fibre-optic cabling is appropriate for long distance communication such as undersea cabling.

Radio waves

Radio waves are the transmission media of wireless networking.
- E.g. WiFi.
- E.g. Bluetooth.
The amplitude (strength) of a radio wave decreases as it moves further from its transmitter. This is why WiFi signal loses strength further away from a WAP.
Radio waves are also subject to interference from other radio signals of similar frequency. Wireless access points (WAPs) often check for frequency channels that are least congested before starting a broadcast.

Coaxial cable

Coaxial cable is a wired transmission media where an insulated copper wire is surrounded by a metal mesh to protect it from interference.
- This is most often used for cable television.

1Computer Systems

1.1Systems Architecture

1.1.1Architecture Introduction

1.1.2Von Neumann Architecture

1.1.3Fetch-Execute Cycle

1.1.4Factors Affecting CPU Performance

1.1.5Elements of Computer Systems

1.1.6Exam-Style Questions - Von Neumann Architecture

1.2Memory & Storage

1.3Computer Networks, Connections & Protocols

1.4Network Security

1.4.1Forms of Attack

1.4.2Malware

1.4.3Social Engineering

1.4.4Phishing

1.4.5Common Active Attacks

1.4.6Information Security

1.4.7SQL Injection

1.4.8Network Administration

1.4.9Protecting Against Malware

1.4.10Authentication & Passwords

1.4.11Encryption

1.4.12End of Topic Test - Networks

1.5Systems Software

1.5.1Types of System Software

1.5.2Operating Systems

1.5.3Operating System Managers

1.5.4File Management

1.5.5Device Management

1.5.6User Management

1.5.7Utility Software: Encryption & Defragmentation

1.5.8Utility Software: Data Compression & Backup

1.6Ethical, Legal, Cultural & Environmental Concern

1.6.1Open Source vs Proprietary Software

1.6.2Licensing Issues

1.6.3Ethical Issues

1.6.4Ethical Issues 2

1.6.5Exam-Style Questions - Ethical Issues

1.6.6Legal Issues

1.6.7Legal Issues 2

1.6.8Freedom of Information Act (2000)

1.6.9Cultural Issues

1.6.10Environmental Issues

1.6.11Positive Environmental Impact

1.6.12Privacy Issues

1.6.13Stakeholders

1.6.14End of Topic Test - Software & Issues

2Computational Thinking, Algorithms and Programming

2.1Algorithms

2.1.1Computational Thinking

2.1.2Algorithmic Thinking

2.1.3Pseudocode & Flow Diagrams

2.1.4Interpreting & Correcting Algorithm

2.1.5Completing Algorithms

2.1.6Search Algorithms

2.1.7Binary Search

2.1.8Overview of Sort Algorithms

2.1.9Bubble Sort & Insertion Sort

2.1.10Merge Sort

2.1.11Exam-Style Questions - Sorting Algorithms

2.2Programming Fundamentals

2.2.1Fundamentals

2.2.2Program Flow 1

2.2.3Program Flow 2

2.2.4Arithmetic & Relational Operators

2.2.5Boolean Operators

2.2.6Data Types

2.2.7Arrays

2.2.8Strings

2.2.9File Handling

2.2.10Structuring Data

2.2.11End of Topic Test - Programming

2.2.12Exam-Style Questions - Translation

2.3Producing Robust Programs

2.3.1Defensive Design Considerations

2.3.2Defensive Design Considerations 2

2.3.3Maintainability

2.3.4Testing

2.3.5Test Plans

2.3.6Error Types

2.3.7End of Topic Test - Programming

2.3.8Exam-Style Questions - Testing

2.4Boolean Logic

2.4.1Computational Logic

2.4.2Boolean Logic

2.4.3Boolean Operators

2.4.4Grade 9 - Logic

2.5Programming Languages & IDEs

2.5.1High-Level vs Low-Level Languages

2.5.2Translation - Compliers & Interpreter

2.5.3Translation - Assemblers

2.5.4Integrated Development Environments

2.5.5Exam-Style Questions - Translation

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