Most Recent CWNP CWAP-404 Exam Questions & Answers

The device finder is a common feature of a spectrum analyzer that helps locate a non-802.11 interference source. The device finder uses a directional antenna to measure the signal strength of a specific frequency or signal source. By pointing the antenna in different directions, the device finder can indicate the direction and distance of the interference source. The device finder can also filter out other signals that are not related to the interference source. The other options are not correct, as they do not help locate a non-802.11 interference source. Max hold and min hold are features that show the maximum and minimum RF power levels over time, respectively. Location filter is a feature that filters out signals that are not from a specific location or area.Reference:[Wireless Analysis Professional Study Guide CWAP-404], Chapter 3: Spectrum Analysis, page 77-78

The most likely issue that can be identified from the spectrum analysis is a power mismatch between the APs and the clients. A power mismatch occurs when the APs transmit at a higher power level than the clients, or vice versa. This can cause asymmetric communication, where one side can hear the other, but not vice versa. This can result in poor performance, disconnections, or packet loss. A spectrum analysis can reveal a power mismatch by showing different signal amplitudes or RSSI values for the APs and the clients on the same channel or frequency. The other options are not correct, as they cannot be identified from the spectrum analysis alone. The tablets' SSID, power save mode, and noise floor can be determined by using other tools or methods, such as protocol analysis, site survey, or device configuration.Reference:[Wireless Analysis Professional Study Guide CWAP-404], Chapter 3: Spectrum Analysis, page 79-80

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 . Reference: 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.

An RTS (Request to Send) frame should be acknowledged by a CTS (Clear to Send) frame. An RTS and CTS frame are types of control frames that are used to implement a virtual carrier sense mechanism called RTS/CTS. RTS/CTS is a technique that helps to avoid collisions and hidden node problems in wireless transmissions. When a STA (station) wants to send a data frame, it first sends an RTS frame to the intended receiver, indicating the duration of the transmission. The receiver then responds with a CTS frame, also indicating the duration of the transmission. The other STAs in the vicinity hear either the RTS or the CTS frame and update their NAV (Network Allocation Vector) timers accordingly, deferring their access to the medium until the transmission is over. The sender then sends the data frame, followed by an ACK (Acknowledgement) frame from the receiver. The other options are not correct, as they are not used to acknowledge an RTS frame. An ACK frame is used to acknowledge a data frame, not an RTS frame. An RTS-Ack frame does not exist, as there is no such type of control frame in 802.11. A Block Ack (BA) frame is used to acknowledge multiple data frames in a single frame, not an RTS frame.Reference:[Wireless Analysis Professional Study Guide CWAP-404], Chapter 6: 802.11 Frame Exchanges, page 166-167

When a data frame is encrypted with WPA2, the encryption is applied to the frame body including the LLCPDU. The LLCPDU (Logical Link Control Protocol Data Unit) is a part of the frame body that contains information such as protocol type, source and destination service access points (SAPs), and control fields. The LLCPDU is added by the LLC (Logical Link Control) sublayer to provide multiplexing and flow control functions for different upper layer protocols. When a data frame is encrypted with WPA2, which uses AES-CCMP as its encryption algorithm, both the payload and the LLCPDU are encrypted as a single unit. The MAC header and FCS are not encrypted, as they are needed for addressing and error detection purposes.Reference:[Wireless Analysis Professional Study Guide CWAP-404], Chapter 5: 802.11 MAC Sublayer, page 115-116