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2.3 Wireless Networks Flashcards

1
Q

Name three wireless frequencies.

A

Direct-sequence spread spectrum, frequency-hopping spread spectrum, orthogonal frequency division multiplexing

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2
Q

What does the DSSS frequency do?

A

Modulates data over an entire range of frequencies using a series of signals known as chips

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3
Q

What does the FHSS do?

A

Allows devices to hop between predetermined frequencies

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4
Q

What does OFDM do?

A

Uses a slow modulation rate with simultaneous transmissions over 52 different data streams

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5
Q

What is a channel?

A

A virtual medium through which wireless networks can send and receive data

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6
Q

How many channels can there be for the 2.5GHz spectrum?

A

11 or 14.

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7
Q

Which three channels avoid overlapping frequencies in the 2.4 GHz band?

A

Channels 1, 6, and 11

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8
Q

How many non-overlapping channels are there in the 5 GHz band?

A

24

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9
Q

What range can wireless networks use in the 5GHz band?

A

5.725-5.875

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10
Q

What is channel bonding?

A

Creating a wider channel by merging neighboring channels into one

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11
Q

What is the standard channel size for both 2.4GHz and 5 GHz networks?

A

20MHz

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12
Q

Which wireless standards support 5GHz?

A

802.11a, 802.11n (Wi-Fi 4), 802.11ac (Wi-Fi 5), 802.11ax (Wi-Fi 6)

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13
Q

Which wireless standard does not support 2.4 GHz?

A

802.11ac (Wi-Fi 5)

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14
Q

Which two wireless standards have a bandwidth of 54 Mbps?

A

802.11a and 802.11g

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15
Q

What is the bandwidth of 802.11b?

A

11Mbps

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16
Q

Which wireless standards support MU-MIMO?

A

802.11ac (Wi-Fi 5)
802.11ax (Wi-Fi 6)

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17
Q

What is Multiple-input and multiple-output (MIMO) when speaking about wireless standards?

A

Uses multiple antennas to send and receive data; can do more than it could with a single antenna

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18
Q

What is multiple-user MIMO? (MU-MIMO)

A

Multiple users can access the wireless network and access point at the same time.

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19
Q

What is the bandwidth of 802.11ax (Wi-Fi 6)?

A

9.6Gbps

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20
Q

What is the bandwidth of 802.11ac (Wi-Fi 5)?

A

3Gbps

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21
Q

What is the bandwidth of 802.11n (Wi-Fi 4) with and without MIMO?

A

150Mbps, 600Mbps

22
Q

When does radio frequency interference occur?

A

When there are similar frequencies to wireless networks in the same area

23
Q

What could cause the signal-to-noise ratio to worsen?

A

Signal decreasing in strength or interference increasing

24
Q

What is a pre-shared key, and in what environment should it not be used?

A

The access point and client use the same encryption key; they shouldn’t be used in large environments

25
What is wired equivalent privacy (WEP)?
The original 802.11 wireless security standard which is now an insecure protocol; it uses 48-bit initialisation vector instead of 24-bit
26
What protocol and initialisation vector (IV) does Wi-Fi protected acceses (WPA) use?
Temporal Key Integrity Protocol (TKIP); 48-bit IV
27
Name some features of WPA
- Rivest Cipher 4 for encryption - Message integrity check (MIC) to confirm data was not modified in transit - Enterprise mode, to authenticate users before exchanging keys
28
When was WPA2 created and what is a unique feature?
As part of the IEEE802.11i standard; requires stronger encryption and integrity checking through CCMP
29
How does advanced encryption standard (AES) provide additional security?
By using a 128-bit key or higher
30
Contrast personal mode and enterprise mode (WPA2).
Personal mode uses a pre-shared key whereas enterprise mode has centralised authentication
31
What does MAC address filtering do?
Configures an access point with a listing of permitted MAC addresses (like an ACL)
32
What does disabling SSID broadcast do?
Configures an access point not to broadcast the name of the wireless LAN
33
What does Wi-Fi 802.11 do?
Creates point-to-point connections from one building to another over a relatively short distance
34
How does cellular Wi-Fi work?
Uses a larger antenna and a larger hotspot powered by a power outlet within an office or home
35
How does microwave Wi-fi work?
Creates point-to-point connections between two plus buildings that have longer distances; traditional links can cover abour 40 miles of distance
36
Contrast low Earth orbit to geosynchronous orbit (satellite Wi-Fi)
Low Earth requires more satellites to cover the planet but gives lower latency; geosynchronous can cover a larger area with higher latency and lower quality
37
How does NFC work?
Electromagnetic charge containing transaction data sent over short distance via radio frequency
38
What is RFID?
A form of radio frequency transmission modified for use in authentication systems
39
What does Infrared Data (IrDA) do?
Allows two devices to communicate using line of sight communication in the infrared spectrum
40
What does Bluetooth do?
Creates a PAN over 2.4 GHz to allow for wireless connectivity
41
What is tethering?
Sharing cellular data internet connection from a smartphone to multiple other devices
42
Define bluejacking
Sending unsolicited messages to a BT device
43
Define Bluesnarfing
Making unauthorised access to a device via BT connection
44
What can Blueborne do?
Allow an attacker to gain complete control over a device without even being connected
45
What are 2 characteristics of the IEEE 802.11a wireless standard?
- Maximum data signalling rate of 54 Mbps - 5 GHz frequency band
46
Which IEEE wireless standard has a maximum data signalling rate of 11 Mbps and works in the 2.4 GHz frequency range?
802.11b
47
Which IEEE wireless standard has a maximum data signalling rate of 54 Mbps and works in the 2.4 GHz frequency range?
802.11g
48
Give two characteristics (other than the frequency bands) of the 802.11n wireless standard.
- MIMO - Maximum data signalling rate of 600Mbps
49
Give the frequency band and the maximum data signalling rate for the 802.11ac (WiFi 5) wireless standard.
- 5 GHz frequency band - 3.39 Gbps
50
What is the maximum data signalling rate for the 802.11ax (WiFi 6) standard?
9.607 Gbps
51
List three directional antenna types suitable for long-range point-to-point bridging links.
- Yagi antenna - Dish antenna - Parabolic antenna

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