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.

1Components of a Computer

1.1Structure & Function of the Processor

1.1.1Structure of the CPU

1.1.2Fetch, Decode, Execute Cycle

1.1.3Factors Affecting CPU Performance

1.1.4CPU Architecture

1.2Types of Processors

1.2.1CISC & RISC

1.2.2Multicore & Parallel Cores

1.3Input, Output & Storage

1.3.1Computer Systems

1.3.2Magnetic Storage

1.3.3Optical Storage

1.3.4Types of Optical Storage

1.3.5Types of Memory

1.3.6Flash Memory

1.3.7Virtual Memory

2Software & Software Development

3Exchanging Data

4Data Types, Data Structures & Algorithms

4.1Data Types

4.1.1Data Types

4.1.2Arrays & Strings

4.1.3Representing Numbers

4.1.4Binary Arithmetic

4.1.5Hexadecimal

4.1.6Converting Binary Numbers

4.1.7Floating Points in Binary

4.1.8Floating Point Arithmetic

4.1.9Bitwise Manipulation

4.1.10Character Sets

4.2Data Structures

4.2.1Arrays, Linked Lists & Queues

4.2.2Graphs, Hash Tables & Stacks

4.2.3Trees

4.3Boolean Algebra

4.3.1Computational Logic

4.3.2Boolean Logic

4.3.3Karnaugh Maps

4.3.4Boolean Identities

4.3.5Flip Flops & Adder Circuits

5Legal, Moral, Cultural & Ethical Issues

5.1Computing Related Legislation

5.1.1Data Protection Act (1998)

5.1.2Computer Misuse Act (1990)

5.1.3Copyright Designs and Patents Act (1988)

5.1.4Regulation of Investigatory Powers Act (2000)

5.2Moral & Ethical Issues

5.2.1Online Activity Tracking

5.2.2Censorship

5.2.3Cultural Issues

5.2.4Environmental Issues

5.2.5Layout, Colour Paradigms & Character Sets

6Elements of Computational Thinking

6.1Thinking Abstractly

6.1.1Abstraction

6.2Thinking Procedurally

6.2.1Decomposition

6.3Thinking Logically

6.3.1Pseudocode & Flow Diagrams

7Problem Solving & Programming

7.1Programming Techniques

7.1.1Programming Fundamentals

7.1.2Modularity

7.2Programming Construction

7.2.1Integrated Development Environments

7.2.2Testing

8Algorithms

8.1Algorithms

8.1.1Interpreting, Correcting & Completing Algorithm

8.1.2Sort Algorithms

8.1.3Insertion & Merge Sort

8.1.4Search Algorithms

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