CWNA-109 VCE Exam Download

The tool described is a WLAN (Wireless Local Area Network) scanner tool. WLAN scanner tools are designed to provide information about the wireless networks in a given area, including:

• Signal Strength: They show the signal strength of all access points (APs) in the vicinity, which is crucial for understanding the coverage area and potential interference.
• SSID Visualization: These tools display the SSIDs (Service Set Identifiers) of available networks, allowing users to identify different wireless networks easily.
• Security Settings Information: WLAN scanner tools often show the type of security implemented on each network, such as WPA2, WEP, etc.
• Frequency Band Filtering: They allow users to filter and view networks based on the frequency band (2.4 GHz or 5 GHz), which is useful for analyzing network distribution and planning.

While protocol analyzers, site survey utilities, and spectrum analyzers are also used in wireless networking, their functions are distinct from what is described:

• Protocol Analyzersare more sophisticated and are used to capture and analyze network traffic.
• Site Survey Utilitiesare used to map signal coverage and plan network layouts, often with more advanced features for detailed site surveys.
• Spectrum Analyzersprovide a detailed view of the frequency spectrum and non-Wi-Fi interference but don't typically focus on SSIDs or security settings.

Thus, the correct answer is D, a WLAN scanner tool, based on the functionalities described.

References:

• CWNA Certified Wireless Network Administrator Official Study Guide: Exam PW0-105, by David D. Coleman and David A. Westcott.
• Tools and techniques for wireless network analysis and troubleshooting.

 A Wi-Fi scanner is a basic tool that can be used to easily locate areas of high co-channel interference. A Wi-Fi scanner is a software application that can run on a laptop, tablet, smartphone, or other device that has a Wi-Fi adapter. A Wi-Fi scanner can scan the wireless environment and display information about the detected access points and client stations, such as their SSID, BSSID, channel, signal strength, security, and data rate. A Wi-Fi scanner can also show the channel utilization and overlap of different access points, which can indicate the level of co-channel interference. Co-channel interference is a type of interference that occurs when multiple access points use the same or adjacent channels within the same coverage area. Co-channel interference can reduce the throughput and performance of the WLAN, as the access points and client stations have to contend for the channel access and avoid collisions. To identify areas of high co-channel interference, a Wi-Fi scanner can be used to measure the signal strength and channel utilization of different access points and compare them with a threshold or a baseline. Alternatively, a Wi-Fi scanner can also use a color-coded heat map to visualize the co-channel interference level in different locations. References: 1, Chapter 7, page 279; 2, Section 4.3

The statement that the lowest voltage drop is achieved when using CAT6 cable instead of Cat5 or CAT5e is true about 802.3, Clause 33 Power over Ethernet. Power over Ethernet (PoE) is a technology that allows electrical power to be delivered over Ethernet cables along with data signals. PoE is defined by IEEE 802.3, Clause 33 and has several variants, such as PoE (802.3af), PoE+ (802.3at), and PoE++ (802.3bt). PoE works by using a device called PSE (Power Sourcing Equipment) that injects power into the Ethernet cable and a device called PD (Powered Device) that receives power from the Ethernet cable. The PSE can be either an endpoint device, such as a switch or a router, or a midspan device, such as an injector or a splitter, that is inserted between two Ethernet devices. The PD can be any device that requires power, such as an access point, a camera, or a phone.

One of the factors that affects PoE performance is voltage drop, which is the reduction of voltage that occurs as current flows through a cable due to its resistance. Voltage drop can cause power loss and inefficiency in PoE systems, as well as damage to PDs if the voltage falls below their minimum requirement. To minimize voltage drop, it is recommended to use high-quality cables with low resistance and short length. Among the common types of Ethernet cables, CAT6 has the lowest resistance and therefore the lowest voltage drop compared to Cat5 or CAT5e. CAT6 also has higher bandwidth and data rate than Cat5 or CAT5e, making it more suitable for PoE applications. References: 1, Chapter 7, page 263; 2, Section 4.4

The short guard interval is an optional feature of 802.11n and 802.11ac that reduces the time between OFDM symbols from 800 ns to 400 ns. This can increase the data rate by about 11%, but also requires more precise timing and synchronization between the transmitter and the receiver. The short guard interval is only used when both the AP and the client support it and agree to use it . References: [CWNA-109 Study Guide], Chapter 4: Radio Frequency Signal and Antenna Concepts, page 163; [CWNA-109Study Guide], Chapter 4: Radio Frequency Signal and Antenna Concepts, page 157.