VDV Wireless Technology 2 — Questions and Answers
Question 1: What is the maximum data rate of 802.11ac (Wi-Fi 5) in the 80 MHz channel configuration?
- 433 Mbps (Correct answer)
- 150 Mbps
- 54 Mbps
- 867 Mbps
Correct answer: 433 Mbps
802.11ac with a single spatial stream in 80 MHz channel width achieves up to 433 Mbps.
Question 2: Which wireless frequency band is most susceptible to interference from microwave ovens?
- 5 GHz
- 2.4 GHz (Correct answer)
- 6 GHz
- 900 MHz
Correct answer: 2.4 GHz
Microwave ovens operate near 2.45 GHz and can significantly interfere with 2.4 GHz Wi-Fi networks.
Question 3: In a MIMO antenna system, what does the term 'spatial multiplexing' refer to?
- Transmitting multiple data streams simultaneously over the same channel (Correct answer)
- Combining signals from multiple antennas to increase range
- Switching between antennas to reduce interference
- Encrypting data across multiple frequency bands
Correct answer: Transmitting multiple data streams simultaneously over the same channel
Spatial multiplexing uses multiple antennas to send independent data streams simultaneously, increasing throughput.
Question 4: What is the purpose of a wireless site survey before installing an enterprise Wi-Fi network?
- To determine IP address assignments
- To identify RF coverage, interference sources, and optimal AP placement (Correct answer)
- To configure SSID names and passwords
- To measure cable run distances
Correct answer: To identify RF coverage, interference sources, and optimal AP placement
A site survey maps RF signal strength, detects interference, and determines optimal access point locations for full coverage.
Question 5: Which Wi-Fi security protocol uses a 4-way handshake to establish encryption keys?
- WEP
- WPA/WPA2 (Correct answer)
- 802.1X only
- TKIP
Correct answer: WPA/WPA2
WPA and WPA2 use a 4-way handshake between the client and access point to derive and confirm the Pairwise Transient Key (PTK).
Question 6: A VDV technician notices a wireless network using channels 1, 5, and 9 in the 2.4 GHz band. What is wrong with this configuration?
- Too many channels are being used
- Channels 1, 5, and 9 overlap with each other
- Only channels 1, 6, and 11 are non-overlapping in the US (Correct answer)
- Channel 5 is not permitted in the US
Correct answer: Only channels 1, 6, and 11 are non-overlapping in the US
In the US 2.4 GHz band, only channels 1, 6, and 11 are non-overlapping; channels 1, 5, and 9 cause co-channel interference.
Question 7: What does the term 'hidden node problem' describe in wireless networks?
- An access point with a hidden SSID
- Two clients that cannot hear each other but both transmit to the same AP, causing collisions (Correct answer)
- A rogue AP broadcasting on a restricted channel
- A client that is out of range of any access point
Correct answer: Two clients that cannot hear each other but both transmit to the same AP, causing collisions
The hidden node problem occurs when two wireless clients are in range of the AP but not each other, causing simultaneous transmissions and collisions at the AP.
VDV Wireless Technology 2
What is the maximum data rate of 802.11ac (Wi-Fi 5) in the 80 MHz channel configuration?