VDV Wireless Technology 5 — Questions and Answers
Question 1: In the context of wireless networks, what does 'roaming' describe?
- Moving an AP to a new location
- A client device transitioning from one access point to another while maintaining connectivity (Correct answer)
- Scanning for rogue access points across the facility
- Broadcasting an SSID across multiple VLANs
Correct answer: A client device transitioning from one access point to another while maintaining connectivity
Wireless roaming is the process by which a mobile client seamlessly transitions its association from one AP to another as it moves through a coverage area.
Question 2: What is the primary advantage of using the 5 GHz band over the 2.4 GHz band for Wi-Fi?
- Greater range and wall penetration
- More available non-overlapping channels and less congestion (Correct answer)
- Lower equipment cost
- Better compatibility with older devices
Correct answer: More available non-overlapping channels and less congestion
The 5 GHz band has up to 25 non-overlapping channels in the US, significantly reducing co-channel interference compared to 2.4 GHz's three non-overlapping channels.
Question 3: Which IEEE standard defines Quality of Service (QoS) for wireless networks, prioritizing voice and video traffic?
- 802.11i
- 802.11e (WMM) (Correct answer)
- 802.11r
- 802.11k
Correct answer: 802.11e (WMM)
802.11e introduced wireless QoS via WMM (Wi-Fi Multimedia), which prioritizes voice, video, best-effort, and background traffic categories.
Question 4: A technician is troubleshooting a DECT phone system that has poor coverage in a large facility. What is the typical operating frequency of DECT in North America?
- 2.4 GHz
- 5.8 GHz
- 1.92 GHz – 1.93 GHz (Correct answer)
- 900 MHz
Correct answer: 1.92 GHz – 1.93 GHz
DECT (Digital Enhanced Cordless Telecommunications) operates in the 1.92–1.93 GHz band in North America, avoiding the crowded 2.4 GHz ISM band.
Question 5: What is the purpose of a captive portal in a wireless network deployment?
- To block rogue APs from joining the network
- To redirect users to an authentication or terms-of-service page before granting internet access (Correct answer)
- To encrypt all wireless traffic using WPA3
- To assign static IP addresses to registered devices
Correct answer: To redirect users to an authentication or terms-of-service page before granting internet access
A captive portal intercepts HTTP traffic and redirects users to a login or terms-of-service page, commonly used in guest Wi-Fi networks.
Question 6: In wireless system design, what does 'link budget' calculation determine?
- The cost of installing wireless infrastructure
- Whether the received signal power will be sufficient to maintain a reliable connection over a given distance (Correct answer)
- The number of users a single AP can support
- The time required to complete a wireless site survey
Correct answer: Whether the received signal power will be sufficient to maintain a reliable connection over a given distance
A link budget accounts for transmit power, antenna gains, cable losses, and free-space path loss to verify adequate signal margin for a wireless link.
Question 7: Which wireless authentication method requires a RADIUS server infrastructure and issues individual credentials per user?
- WPA2-Personal (PSK)
- WEP Open Authentication
- WPA2-Enterprise (802.1X) (Correct answer)
- MAC address filtering
Correct answer: WPA2-Enterprise (802.1X)
WPA2-Enterprise uses 802.1X authentication with a RADIUS server, requiring each user to present unique credentials (username/password or certificate).
VDV Wireless Technology 5
In the context of wireless networks, what does 'roaming' describe?