A corporate office complains of intermittent Wi-Fi drops on channel 149 (5745 MHz). A spectrum analyzer shows a signal with a ~75% duty cycle that appears for 2-3 seconds at a time, sweeps across a 20 MHz channel width, and has a very fast rise time. The signal is present even when no Wi-Fi devices are actively transmitting. Which non-802.11 device is the most likely source of this interference?
A network uses WMM for QoS. A protocol capture of a VoIP call shows that voice packets (AC_VO) are experiencing high latency. Analysis of the AP's beacon frames reveals the following EDCA Parameter Set for AC_VO: AIFSN=2, CWmin=3, CWmax=7, TXOP Limit=1504 µs. The capture also shows frequent transmissions from clients in the Best Effort queue (AC_BE) with AIFSN=3, CWmin=15, CWmax=1023, TXOP Limit=0. What is the most likely cause of the high latency for voice traffic? ```mermaid flowchart TD Start((Start Contention)) --> CheckIdle{Medium Idle for AIFS?} CheckIdle -- No --> Start CheckIdle -- Yes --> Backoff[Select Random Backoff] Backoff --> Decrement{Decrement Counter} Decrement -- Counter > 0 --> CheckIdle Decrement -- Counter == 0 --> Transmit[Transmit Frame] Transmit --> End((End Contention)) subgraph AC_VO AIFS_VO(AIFSN=2) CW_VO(CWmin=3, CWmax=7) end subgraph AC_BE AIFS_BE(AIFSN=3) CW_BE(CWmin=15, CWmax=1023) end ```
A user is unable to connect to a WPA2-Personal network. A frame capture shows the client receiving Message 1 (ANonce) from the AP and sending Message 2 (SNonce, MIC). However, the AP never sends Message 3. Instead, after a timeout, the AP retransmits Message 1. This cycle repeats. What is the most probable cause of this failure?
A wireless analyzer captures a data frame where the `To DS` bit is 1 and the `From DS` bit is 1 in the Frame Control field. Which type of communication does this frame represent? ```mermaid graph TD subgraph BSS1 STA1[Client STA 1] end subgraph BSS2 STA2[Client STA 2] end AP1((Access Point 1)) AP2((Access Point 2)) STA1 -- Frame --> AP1 AP1 -- WDS Link --- AP2 AP2 -- Frame --> STA2 linkStyle 1 stroke:#f00,stroke-width:2px,fill:none; ```
A large retail warehouse uses handheld scanners connected via a 5 GHz 802.11ac network. Scanners frequently disconnect and reconnect, taking 5-10 seconds each time, which causes significant productivity loss. The network uses WPA2-Enterprise with EAP-TLS. A wireless engineer is tasked with identifying the root cause. The engineer performs a multi-channel capture near a problematic area and filters for the MAC address of a failing scanner. The capture shows the scanner roams from AP-1 to AP-2. The reassociation with AP-2 is successful and happens within 50ms. However, a full EAP-TLS exchange follows the reassociation, which takes over 6 seconds to complete before the 4-way handshake can begin. The RADIUS server is located on a remote corporate network accessible over a WAN link. Analysis of the EAP exchange shows significant delays between the RADIUS server's messages. What is the most likely issue and the best remediation step?
An analyst examines a captured 802.11ax frame using Wireshark. The Radiotap header contains the "HE Information" field. Within this field, BSS Color is set to 12, and the UL/DL flag is set to 1 (Uplink). What is the primary purpose of the BSS Color value in this context?
A network administrator needs to verify that an access point is correctly advertising support for WPA3-Personal and 802.11k for assisted roaming. Which TWO of the following Information Elements should be present and correctly configured in the AP's Beacon and Probe Response frames? (Select TWO)
True or False: In the 802.11 DCF contention mechanism, a station that wins contention and transmits a frame must wait for a DIFS period plus a new random backoff before transmitting its next frame, even if the medium remains idle after it receives the ACK.
A spectrum analyzer in a dense office environment shows the following on the 2.4 GHz band: A strong 802.11g signal centered on channel 6. Another slightly weaker 802.11g signal is also visible, centered on channel 7. The energy from the channel 7 signal bleeds significantly into the frequency space of channel 6. How should this interference be classified, and what is its primary impact?
A protocol capture of a file transfer shows an AP sending a Block Ack Request (BAR) frame to a client. The BAR frame's 'Starting Sequence Number' is 100. The client responds with a Block Ack (BA) frame. The BA's bitmap field, when decoded, indicates that frames with sequence numbers 101, 102, and 104 were received successfully, but 100 and 103 were not. What will the AP do next?