Computer Network
Unit 8 Summary - Part 1
You can create your own home network, what you need is:
1. NIC (Network Interface card) inside each computer.
2. A driver (software) to use the NIC.
3. A transmission medium: wifi(lan, man, wan)/bluetooth/internet.
4. A switch/router.
What is a transmission medium?
LAN
is to connect computers that are nearby in your network.
WAN
is used to connect computers that are far away.
The internet is a global WAN
Switch vs Router vs Hub
Benefits of having a network:
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You can share or update files quickly from one computer to another without using an internet.
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1 printer can be used by all computers without moving their computer to the printer.
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You can chat to another computer user within the same network without using the internet.
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1 internet connection can be used by all computers in the same network
Disadvantages of having a network:
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A home network is not really expensive, but you need to buy a router,
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An office network is very expensive because it needs a server, and a very cool room, and needs to run 24 hours to be accessed by anyone outside of the office.
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A hacker might steal your data, or you might share a private folder by accident.
Long time ago, we used modems to connect to the internet with dial up phone, and it made this sound.
Wired vs Wireless
Commonly used cables
Fibre optic cables
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made of transparent plastic rods,
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signals are sent down as pulses of light, not affected by electrical interference,
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used for long-distance connection,
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faster than twisted pair cables (high speed).
Twisted pair cables
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a couple of copper wires twisted together,
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signals are sent down as electrical pulses, they're cheap & flexible,
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for up to 90 metres distance only,
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slower than fibre optic.
Wireless network uses radio frequencies.
Broadband:
wireless connection that uses a wide range of frequencies, allows several signals to be carried at once, that means large files / a lot of data can be transmitted at once.
Oxford AQA IGCSE 2019
03.2.
WANs and LANs are two different types of network. State one difference between a WAN and a LAN. [1 mark]
__________________________________________________________________________________
Answer posibilities:
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LANs cover a limited geographical area (typically one building/site), WANs cover a large geographical area (more than one building/site)
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WANs are (typically) public networks, LANs (typically) carry less traffic than WANs
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WANs are (typically) under shared ownership, LANs are (typically) owned by a single person or organisation;
Oxford AQA IGCSE 2020
02.
Computers on a network can be connected using wires or wirelessly. State the advantages and disadvantages of wired networking compared to wireless networking. [6 marks]
__________________________________________________________________________________
Answer posibilities:
Advantages of wired networks:
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Faster transmission speeds; More reliable transmission
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less interference; More secure (connection)
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harder to intercept signal
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more difficult to achieve unauthorised access;
Disadvantages of wired networks:
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Need to lay cables which is expensive/inconvenient/unattractive; Wiring faults can be difficult to locate
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wiring faults may stop network working; Cables can cause trip/safety hazards; Can only connect at fixed locations (which are more limited than for a wireless network)
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cannot move devices easily; Some devices can only connect wirelessly as they don’t have a port for a wired network;
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Can be more expensive/harder to add new devices (if need additional cabling/ports/switch);
Oxford AQA IGCSE Specimen Paper
06.
A student is going to set up a computer network at home.
The computer network will be used to connect together a range of devices including a desktop computer, laptops, a printer and a TV with internet connection.
06.1.
Explain two advantages of setting the network up as a wireless network. [2 marks]
__________________________________________________________________________________
06.2.
Explain two advantages of setting the network up as a wired network. [2 marks]
__________________________________________________________________________________
