CWNA-109 Dumps With Exact Questions and Answers

The FCS (Frame Check Sequence) is appended to the end of each 802.11 data frame after the payload. The FCS is a 4-byte field that contains a CRC-32 (Cyclic Redundancy Check) value that is calculated based on the contents of the MAC header and the payload of the frame. The FCS is used by the receiver to verify the integrity of the frame and to detect any errors or corruption that may have occurred during transmission. If the FCS does not match with the expected value, the frame is discarded by the receiver.  References:  , Chapter 4, page 139; , Section 4.2

A laptop-based spectrum analyzer with a directional antenna is the best solution for locating a non-802.11 device that is suspected of causing interference on the WLAN. A spectrum analyzer is a device or a software application that can measure and display the frequency spectrum of electromagnetic signals in a given range. A spectrum analyzer can show the amplitude, frequency, bandwidth, modulation, and other characteristics of different signals in the spectrum, which can help identify their sources and types. A spectrum analyzer can also detect non-802.11 devices that may cause interference on the WLAN, such as microwave ovens, cordless phones, Bluetooth devices, or radar systems. A laptop-based spectrum analyzer is a software application that runs on a laptop computer and uses an external USB adapter as its RF interface. A laptop-based spectrum analyzer has the advantage of being portable, flexible, and cost-effective compared to a hardware-based spectrum analyzer. A directional antenna is an antenna that radiates or receives RF signals more strongly in one direction than in others. A directional antenna has a high gain and a narrow beamwidth, which means it can focus the RF energy in a specific direction and reduce the interference from other directions. A directional antenna can also increase the range and sensitivity of the RF signal detection. To locate a non-802.11 device that is causing interference on the WLAN, a laptop-based spectrum analyzer with a directional antenna can be used to perform a technique called RF hunting or triangulation. This technique involves pointing the directional antenna in different directions and observing the signal strength and characteristics of the interfering device on the spectrum analyzer.  By moving around and changing the direction of the antenna, the location of the interfering device can be estimated based on where the signal strength is highest and most consistent.  References:   1 , Chapter 7, page 282;  2 , Section 4.3

 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.