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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What is a LAN?

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


What is a WAN?

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


What is the biggest WAN?

The Internet


What does WAN stand for?

Wide area network


What does LAN stand for?

Local area network


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


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


What are the disadvantages of using a LAN?

Managing a large network is complicated

Viruses which infiltrate the network infect all computers


How are WANs connected?

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


How are LANs connected?

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


What factors affect the performance of a network?

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


What is bandwidth?

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


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


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


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


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


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


What is wireless performance affected by?

Range of the device
Physical obstructions


Give an example of a physical obstruction

Thick walls in buildings


How do physical obstructions reduce network performance?

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


How does interference affect network performance?

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


What is the contention ratio?

The number of users : available bandwidth


What does a 100:1 contention ratio mean?

Up to 100 users can share the line at any time


What does a 1:1 contention ratio mean?

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


What is the difference between CAT5e and CAT6 cables?

CAT6 cables are faster, and give a greater bandwidth


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


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


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


Where is the NIC found in a computer?

Is often built on chips in the motherboard


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