1.4 Wired And Wireless Networks Flashcards Preview

OCR GCSE (9-1) Computer Science > 1.4 Wired And Wireless Networks > Flashcards

Flashcards in 1.4 Wired And Wireless Networks Deck (39)
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1

What is a LAN?

A network connecting devices over a small geographical area, e.g. a school or business

2

What is a WAN?

A network connecting LANs in different geographical locations over a large geographical area, e.g. between 3 cities

3

What is the biggest WAN?

The Internet

4

What does WAN stand for?

Wide area network

5

What does LAN stand for?

Local area network

6

Name 3 differences between LANs and WANs

LANs connect devices over a small geographical area, while WANs connect LANs over a large geographical area

All LAN infrastructure is owned by the company themselves, whereas WAN infrastructure is hired from telecommunications companies, who own and manage the WAN

LANs are connected wirelessly using WiFi or wired using Ethernet cables, while WANs are connected using copper telephone lines, satellite links, radio links or fibre optic cables

7

What are the advantages of using a LAN?

Users can communicate cheaply and easily with each other, e.g. with instant messaging

User accounts are stored centrally, therefore users can log in and access their files from any device on the network

Allows sharing of files and collaboration

Allows sharing of peripherals such as printers

Allows the sharing of the internet connection between every device on the LAN

Computers are managed centrally so software can be installed and updated on all computers at once

8

What are the disadvantages of using a LAN?

Managing a large network is complicated

Viruses which infiltrate the network infect all computers

9

How are WANs connected?

Using copper telephone lines, fibre optic cables, satellite links or radio links

10

How are LANs connected?

Wired (e.g. using Ethernet cables)
Wireless (e.g. using WiFi)

11

What factors affect the performance of a network?

Bandwidth
Network traffic
Interference
Physical obstructions
Hardware (Wired/wireless, Copper cables/fibre optic)
Range

12

What is bandwidth?

The maximum amount of data that can be transferred in a given time, e.g. 500 Mbps

13

How does bandwidth affect network performance?

The more bandwidth, the more data that can be transferred per second, therefore the better the network can perform:

Available bandwidth is shared between users of a network - too many/heavy use causes congestion and slow the network

14

Available bandwidth is shared between users of a network - too many/heavy use causes congestion and slow the network.

How can we address this issue?

By increasing the bandwidth

By limiting the bandwidth available to individual users

15

Which provides better network performance: wired or wireless connections? Why?

Wired - generally faster and more reliable

Greater bandwidth (up to 10 Gbps rather than up to 600 Mbps)

No interference with cables

16

What is a network?

A group of computer systems and other devices linked together so that they can communicate and share resources such as printers

17

Which provides better network performance: copper cables or fibre optic cables? Why?

Fibre optic - don’t suffer interference and can transmit over very large distance without loss of signal quality

Transmit signals at much greater speeds and over greater distances

18

What is wireless performance affected by?

Range of the device
Interference
Physical obstructions

19

Give an example of a physical obstruction

Thick walls in buildings

20

How do physical obstructions reduce network performance?

Prevent the transmission of data in wireless connections therefore decrease network performance

21

How does interference affect network performance?

Signals on adjacent channels interfere with one another and lower each other’s performance

22

What is the contention ratio?

The number of users : available bandwidth

23

What does a 100:1 contention ratio mean?

Up to 100 users can share the line at any time

24

What does a 1:1 contention ratio mean?

Only one user can make a connection on the line at any one time

25

What is the difference between CAT5e and CAT6 cables?

CAT6 cables are faster, and give a greater bandwidth

26

How does range affect network performance?

All signals have a maximum range (with 2.4 GHz signals having a greater range than 5), and as the limit is approached, performance decreases due to increased distance

27

How does high network traffic affect performance ?

Can lead to data package collisions, therefore loss of data and transmission errors – these packetsw have to be re-sent

28

What is an NIC?

Network Interface controller

An internal piece of hardware which allows the computer to connect to a network

Formats the data sent to and received by the computer

29

Where is the NIC found in a computer?

Is often built on chips in the motherboard

30

What is a router?

Connects to different LANs and direct data packets to destination over a WAN by reading the IP address and forwarding the data to the correct network

Always connects to at least two different networks

Use to transfer data between the LAN and the Internet