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Core 1 > 2.3 Wireless Networks > Flashcards

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
Q

What is wired equivalent privacy (WEP)?

A

The original 802.11 wireless security standard which is now an insecure protocol; it uses 48-bit initialisation vector instead of 24-bit

26
Q

What protocol and initialisation vector (IV) does Wi-Fi protected acceses (WPA) use?

A

Temporal Key Integrity Protocol (TKIP); 48-bit IV

27
Q

Name some features of WPA

A
  • 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
Q

When was WPA2 created and what is a unique feature?

A

As part of the IEEE802.11i standard; requires stronger encryption and integrity checking through CCMP

29
Q

How does advanced encryption standard (AES) provide additional security?

A

By using a 128-bit key or higher

30
Q

Contrast personal mode and enterprise mode (WPA2).

A

Personal mode uses a pre-shared key whereas enterprise mode has centralised authentication

31
Q

What does MAC address filtering do?

A

Configures an access point with a listing of permitted MAC addresses (like an ACL)

32
Q

What does disabling SSID broadcast do?

A

Configures an access point not to broadcast the name of the wireless LAN

33
Q

What does Wi-Fi 802.11 do?

A

Creates point-to-point connections from one building to another over a relatively short distance

34
Q

How does cellular Wi-Fi work?

A

Uses a larger antenna and a larger hotspot powered by a power outlet within an office or home

35
Q

How does microwave Wi-fi work?

A

Creates point-to-point connections between two plus buildings that have longer distances; traditional links can cover abour 40 miles of distance

36
Q

Contrast low Earth orbit to geosynchronous orbit (satellite Wi-Fi)

A

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
Q

How does NFC work?

A

Electromagnetic charge containing transaction data sent over short distance via radio frequency

38
Q

What is RFID?

A

A form of radio frequency transmission modified for use in authentication systems

39
Q

What does Infrared Data (IrDA) do?

A

Allows two devices to communicate using line of sight communication in the infrared spectrum

40
Q

What does Bluetooth do?

A

Creates a PAN over 2.4 GHz to allow for wireless connectivity

41
Q

What is tethering?

A

Sharing cellular data internet connection from a smartphone to multiple other devices

42
Q

Define bluejacking

A

Sending unsolicited messages to a BT device

43
Q

Define Bluesnarfing

A

Making unauthorised access to a device via BT connection

44
Q

What can Blueborne do?

A

Allow an attacker to gain complete control over a device without even being connected

45
Q

What are 2 characteristics of the IEEE 802.11a wireless standard?

A
  • Maximum data signalling rate of 54 Mbps
  • 5 GHz frequency band
46
Q

Which IEEE wireless standard has a maximum data signalling rate of 11 Mbps and works in the 2.4 GHz frequency range?

A

802.11b

47
Q

Which IEEE wireless standard has a maximum data signalling rate of 54 Mbps and works in the 2.4 GHz frequency range?

A

802.11g

48
Q

Give two characteristics (other than the frequency bands) of the 802.11n wireless standard.

A
  • MIMO
  • Maximum data signalling rate of 600Mbps
49
Q

Give the frequency band and the maximum data signalling rate for the 802.11ac (WiFi 5) wireless standard.

A
  • 5 GHz frequency band
  • 3.39 Gbps
50
Q

What is the maximum data signalling rate for the 802.11ax (WiFi 6) standard?

A

9.607 Gbps

51
Q

List three directional antenna types suitable for long-range point-to-point bridging links.

A
  • Yagi antenna
  • Dish antenna
  • Parabolic antenna

Core 1 (27 decks)

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