Free CWAP-404 Exam Braindumps

Finish the statement:
It is possible to distinguish between _______ 22 MHz transmissions and ______ 20 MHz transmissions when looking at an FFT plot.

1. A. HR/DSSS and ERP
2. B. OFDM and HT
3. C. ERP and VHT
4. D. HT and VHT

Correct Answer: B
It is possible to distinguish between OFDM 20 MHz transmissions and HT 20 MHz transmissions when looking at an FFT plot. OFDM and HT are two different modulation schemes used by 802.11 WLANs. OFDM is used by legacy 802.11a/g devices, while HT is used by newer 802.11n/ac devices. OFDM and HT have different spectral characteristics that can be observed on an FFT plot. OFDM transmissions have a flat spectrum with sharp edges, while HT transmissions have a tapered spectrum with rounded edges. This is because HT uses guard intervals and cyclic prefixes to reduce inter-symbol interference and improve performance. The other options are not correct, as they do not describe different modulation schemes or channel widths that can be distinguished on an
FFT plot. References: [Wireless Analysis Professional Study Guide CWAP-404], Chapter 3: Spectrum Analysis, page 70-71

You are performing a multiple adapter channel aggregation capture to troubleshoot a VoIP roaming problem and would like to measure the roaming time from the last VoIP packet sent on the old AP's channel to the first VoIP packet sent on the new AP's channel. Which timing column in the packet view would measure this for you?

1. A. Roaming
2. B. Relative
3. C. Absolute
4. D. Delta

Correct Answer: D
Delta is the timing column in the packet view that measures the time difference between two consecutive packets in a capture file. Delta can be used to measure the roaming time from the last VoIP packet sent on the old AP??s channel to the first VoIP packet sent on the new AP??s channel by selecting these two packets and looking at their delta values. The other timing columns are not suitable for this measurement because they do not show the time difference between two specific packets. Roaming is a column that shows whether a packet belongs to a roaming event or not. Relative is a column that shows the time elapsed since the beginning of the capture file. Absolute is a column that shows the date and time when a packet was captured5 References:
✑ CWAP-404 Study Guide, Chapter 2: Protocol Analysis, page 57
✑ CWAP-404 Objectives, Section 2.4: Analyze timing values

In a Spectrum Analyzer the Swept Spectrogram plot displays what information?

1. A. RF power present at a particular frequency over the course of time
2. B. Reductions in frame transmissions
3. C. Wi-Fi Device information
4. D. The RF time domain

Correct Answer: A
The Swept Spectrogram plot is a spectrum analysis plot that shows the RF power present at a particular frequency over the course of time. It can help identify trends and patterns in the RF spectrum over a longer period of time. It can also show how the RF environment changes over time and how different sources of RF signals affect each other. The other options are not correct, as they describe different types of plots or information that are not related to the Swept Spectrogram plot. References: [Wireless Analysis Professional Study Guide], Chapter 3: Spectrum Analysis, page 72-73

What is the function of the PHY layer?

1. A. Convert PPDUs to PSDUs for transmissions and PSDUs to PPDUs for receptions
2. B. Convert MSDUs to PPDUs for transmissions and PPDUs to MSDUs for receptions
3. C. Convert PPDUs to MSDUs for transmissions and MSDUs to PPDUs for receptions
4. D. Convert PSDUs to PPDUs for transmissions and PPDUs to PSDUs for receptions

Correct Answer: D
The function of the PHY layer is to convert PSDUs to PPDUs for transmissions and PPDUs to PSDUs for receptions. A PSDU (PHY Service Data Unit) is the data unit that is passed from the MAC layer to the PHY layer for transmission, or from the PHY layer to the MAC layer for reception. A PPDU (PHY Protocol Data Unit) is the data unit that is transmitted or received over the wireless medium by the PHY layer. A PPDU consists of a PSDU and a PHY header, which contains information such as modulation, coding, and data rate. The PHY layer adds or removes the PHY header to or from the PSDU during the conversion process. References: [Wireless Analysis Professional Study Guide CWAP-404], Chapter 4: 802.11 Physical Layer, page 97-98

When would you expect to see a Reassociation Request frame'

1. A. Every time a STA associates to an AP to which it has previously been associated
2. B. Only when a STA is using FT roaming
3. C. Only when a STA roams back to an AP it has previously been associated with
4. D. Every time a STA roams

Correct Answer: D
A Reassociation Request frame is sent every time a STA roams from one AP to another within the same ESS. A Reassociation Request frame is similar to an Association Request frame, but it also contains the BSSID of the current AP that the STA is leaving. This allows the new AP to coordinate with the old AP and transfer the STA??s context information, such as security keys, QoS parameters, and buffered frames. This way, the STA can maintain its connectivity and session continuity during roaming . References: CWAP-404 Certified Wireless Analysis Professional Study and Reference Guide, Chapter 6: MAC Sublayer Frame Exchanges, page 195;CWAP-404 Certified Wireless Analysis Professional Study and Reference Guide, Chapter 6: MAC Sublayer Frame Exchanges, page 196.