Score Higher on Verified CWNA-109 | Certified Wireless Network Administrator Exam Questions with Answers

The final step in an effective troubleshooting process is to document the results. Documentation is essential for keeping track of the problem history, the actions taken, the solutions implemented, and the outcomes achieved. Documentation can also help to prevent future problems, improve best practices, and provide feedback for improvement. Documentation should include relevant information such as problem description, symptoms, root cause analysis, resolution steps, verification methods, and lessons learned. References: [CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 513; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 483.

In the 802.11 wireless networking protocols, when a client station sends a broadcast probe request frame with a wildcard SSID (Service Set Identifier), it is essentially asking for any nearby access points (APs) to identify themselves. The way APs respond to such a probe request is governed by standard 802.11 behavior, which includes:

Probe Request Handling: Upon receiving a broadcast probe request, each AP that can serve the client prepares a probe response. The response includes information about the AP, such as its SSID, supported data rates, and other capabilities.

Contention-Based Mechanism: Wireless networks use a contention-based mechanism (CSMA/CA - Carrier Sense Multiple Access with Collision Avoidance) for medium access. Each AP must wait for a clear channel and win the contention process before it can send its probe response.

Independent Responses: Each AP operates independently in responding to the probe request. There is no coordination between APs to decide which one responds first or at all, leading to multiple APs sending probe responses, each after winning the contention for the medium.

Option A accurately reflects this process, indicating that each AP prepares and sends a probe response in turn, contingent upon winning the medium contention. The other options suggest mechanisms (such as coordination with a DHCP server or simultaneous responses after a Short Interframe Space (SIFS)) that do not align with standard 802.11 procedures for handling broadcast probe requests.

 The most effective method for testing roaming in relation to 802.11 VoIP handsets is to place a call with the handset and move around the facility to test quality during roaming. This method allows you to evaluate the actual performance and user experience of VoIP calls over wireless networks, as well as identify any potential issues such as signal strength, interference, latency, jitter, packet loss, or handoff delays. A spectrum analyzer can only show you the RF activity during a VoIP call, but not how it affects the voice quality or roaming behavior. A protocol analyzer can capture the traffic generated when a laptop roams, but it cannot simulate the characteristics of a VoIP handset such as battery life, antenna design, codec support, or QoS features. A built-in roaming monitor is not a common feature in all VoIP handsets, and it may not provide accurate or comprehensive information about the roaming process. References: [CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 487; [Voice over Wireless LAN 4.1 Design Guide], page 6-19.