You're the WLAN administrator for a large retailer based at the HQ in New York. The London-based office has been complaining about WLAN disconnections around lunch time each day. You suspect this might be interference from the staff microwave, how might you test your theory from the New York office?

Place one of the London APs into spectrum analyzer mode and monitor the situation over lunch time

Ask a local member of staff to change the frequency of the microwave and see if the disconnections stop

Ask a local member of staff to take some pictures of the microwave, including some close-ups of the door seal so that you can assess it

Access the microwave remotely and run a diagnostic check

Place one of the London APs into spectrum analyzer mode and monitor the situation over lunch time

As a wireless network consultant you have been called in to troubleshoot a high-priority issue for one of your customers. The customer's office is based on two floors within a multi-tenant office block. On one of these floors (floor 5) users cannot connect to the wireless network. During their own testing the customer has discovered that users can connect on floor 6 but not when they move to the floor 5. This issue is affecting all users on floor 5 and having a negative effect on productivity.To troubleshoot this issue, you perform both Spectrum and Protocol Analysis. The Spectrum Analysis shows the presence of Bluetooth signals which you have identified as coming from wireless mice. In the protocol analyzer you see the top frame on the network is Deauthentication frames. On closer investigation you see that the Deauthentication frames' source addresses match the BSSIDs of your customers APs and the destination address is FF:FF:FF:FF:FF:FF:FF.What do you conclude from this troubleshooting exercise?

The users on floor 5 are being subjected to a denial of service attack, as this is happening across the entire floor it is likely to be a misconfigured WIPS solution belonging to the tenants on the floor below

The customer should replace all their Bluetooth wireless mice as they are stopping the users on floor 5 from connecting to the wireless network

The users on floor 5 are being subjected to a denial of service attack, as this is happening across the entire floor it is likely to be a misconfigured WIPS solution belonging to the tenants on the floor below

The customers APs are misbehaving and a technical support case should be open with the vendor

The CCI from the APs on the floor 4 is the problem and you need to ask the tenant below to turn down their APs Tx power

ABC International has installed a new smart ZigBee controlled lighting system. However, the network team is concerned that this new system will interfere with the existing WLAN and has asked you to investigate the impact of the two systems operating simultaneously in the 2.4 GHz band. When performing Spectrum Analysis, which question could you answer by looking at the FFT plot?

Do the ZigBee channels used by the lighting system overlap with the WLAN channels?

Is the ZigBee system using more than 50% of the available airtime?

Is the WLAN corrupting ZigBee system messages?

Is the ZigBee system causing an increase in WLAN retries?

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

RF power present at a particular frequency over the course of time

Reductions in frame transmissions

You have installed a new 802.1 lac WLAN configured with 80 MHz channels. Users in one area are complaining about poor performance. This area is currently served by a single AP. You take a spectrum analysis capture in the poor performing are a. While examining the waterfall plot you notice the airtime utilization is higher on the first 20 MHz of the 80 MHz channel when compared to the rest of the channel. What do you conclude?

Non-Wi-Fi interference is preventing the APs 80 MHz operation

The AP is misconfigured and needs to be reconfigured to 80 MHz operation

Non-Wi-Fi interference is preventing the APs 80 MHz operation

The first 20 MHz is the AP's primary channel and higher airtime utilization on the primary channel is normal when an AP is configured for 80 MHz operation

RRM is enabled and has dynamically picked a 20 MHz channel

Which one of the following should be the first step when troubleshooting a WLAN issue?

Perform an initial WLAN scan and see if any obvious issues stand out

Which one of the following is an advantage of using display filters that is not an advantage of capture-time filters?

They only hide the packets from view and the filtered packets can be enabled for view later

They allow for focused analysis on just the packets of interest

Once created they are reusable for later captures

They only hide the packets from view and the filtered packets can be enabled for view later

Multiple of them can be applied simultaneously

Using a portable analyzer you perform a packet capture next to a client STA and you can see that the STA is associated to a BSS. You observe the STA sending packets to the AP and the AP sending packets to the ST

There is a transmit power mismatch between the client and the AP and while the client can hear the APs traffic, the AP cannot hear the client

Less than 2% of all packets are retransmissions. You move to capture packets by the AP and, while the retry rate is still less than 2%, you now only see unidirectional traffic from the AP to the client. How do you explain this behavior?

The portable analyzer is too close to the AP causing CCI, blinding the AP to the clients packets

The STA is transmitting data using more spatial streams than the potable analyzer can support

There is a transmit power mismatch between the client and the AP and while the client can hear the APs traffic, the AP cannot hear the client

The portable analyzer has a lower receive sensitivity than the AP and while it can't capture the packets from the client STA, the AP can receive them OK

Which one of the these is the most important in the WLAN troubleshooting methodology among those listed?

Obtain detailed -knowledge of the wireless vendors debug and logging options

Interview the network manager about the issues being experienced

Talk to the end users about their experiences

A manufacturing facility has installed a new automation system which incorporates an 802.11 wireless network. The automation system is controlled from tablet computers connected via the WLAN. However, the automation system has not gone live due to problem with the tablets connecting to the WLAN. The WLAN vendor has been onsite to perform a survey and confirmed good primary and secondary coverage across the facility. As a CWAP you are called in to perform Spectrum Analysis to identify any interference sources. From the spectrum analysis, you did not identify any interference sources but were able to correctly identify the issue. Which of the following issues did you identify from the spectrum analysis?

There is a power mismatch between the APs and the clients

The tablets are connecting to the wrong SSID

The tablets are entering power save mode and failing to wake up to receive the access points transmissions

A high noise floor has resulted in a SNR of less than 20dB

There is a power mismatch between the APs and the clients

What is the function of the PHY layer?

Convert PSDUs to PPDUs for transmissions and PPDUs to PSDUs for receptions

Convert PPDUs to PSDUs for transmissions and PSDUs to PPDUs for receptions

Convert MSDUs to PPDUs for transmissions and PPDUs to MSDUs for receptions

Convert PPDUs to MSDUs for transmissions and MSDUs to PPDUs for receptions

Convert PSDUs to PPDUs for transmissions and PPDUs to PSDUs for receptions

What is the function of the PHY Preamble?

Allows the receiver to detect and synchronize with the signal

To terminate a conversation between transmitter and receiver

To set the modulation method for the MPDU

Carries the NDP used in Transmit Beamforming and MU-MIMO

Allows the receiver to detect and synchronize with the signal

Given: The Frame Check Sequence (FCS) is a 32 CRC used for error detection.The CRC is calculated over what?

PHY Header, MAC Header and Frame Body

Where would you look in a packet trace file to identify the configured Minimum Basic Rate (MBR) of a BSS?

Supported Rates & Extended Supported Rates elements in a Beacon frame

In the MBR Information Element in an Association Response frame

In the Minimum Basic Rate Element in a Beacon frame

After examining a Beacon frame decode you see the SSID Element has a length of 0. What do you conclude about this frame?

The beacon is from a BSS configured to hide the SSID

SSID elements always have a length of 0

This is a common attack on WISP backend SQL databases

The beacon is from a BSS configured to hide the SSID

A client is operating in an unstable RF environment. Out of five data frames transmitted to the client it only receives four. The client sends a Block Ack to acknowledge the receipt of these four frames but due to frame corruption the Block Ack is not received by the AP. Which frames will be retransmitted'

Both the corrupted data and Block Ack

Only the data frame which was corrupted

When a data frame is encrypted with WPA2, to which portion of the frame is the encryption applied?

Frame body including the LLCPDU

Frame body excluding the LLCPD U

Frame body including the LLCPDU

You are troubleshooting a client that is experiencing slow WLAN performance. As part of the troubleshooting activity, you start a packet capture on your laptop close to the client device. While analyzing the packets, you suspect that you have not captured all packets transmitted by the client. By analyzing the trace file, how can you confirm if you have missing packets?

Look for gaps in the sequence number in MAC headers.

The missing packets will be shown as CRC errored packets

Protocol Analyzers show the number of missing packets in their statistics view

Look for gaps in the sequence number in MAC headers.

Retransmission are an indication of missing packets

What is the function of 802.11 Management frames?

Prioritize network administration traffic

Communicate configuration changes between WLAN controller and APs

CWNP CWAP-404 Practice Test 1 - Free Online Exam Prep & Questions

Question 1 / 40

Which one of the following is required for Wi-Fi integration in laptop-based Spectrum Analyzer software in addition to the spectrum analysis adapter?

An 802.11 wireless adaptor

A firmware upgrade for the spectrum analysis adapter

A directional antenna

SNMP read credentials to the WLAN controller or APs

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