CWNA-109 Exam Dumps : Certified Wireless Network Administrator

The client STA can use Beacon frames transmitted by the AP to verify that an AP supports the same data rates that it supports. Beacon frames are management frames that are periodically broadcasted by the APs to announce their presence, capabilities, and parameters. One of the information elements contained in the Beacon frames is the Supported Rates or Extended Supported Rates, which lists the data rates that the AP can use for communication. The client STA can compare its own data rates with those advertised by the AP to determine if they are compatible. Data frames, authentication frames, and probe request frames do not contain information about data rates. References: [CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 133; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 123.

Channel 144 is a new channel that was added to the 5 GHz band by the 802.11ac amendment, which defines the VHT (Very High Throughput) PHY for WLANs. Channel 144 has a center frequency of 5720 MHz and a bandwidth of 20 MHz. It can also be combined with adjacent channels to form wider channels of 40 MHz, 80 MHz, or 160 MHz. Channel 144 is available in some regions, such as North America and Europe, but not in others, such as Japan and China . References: [CWNA-109 Study Guide], Chapter 3: Antennas and Accessories, page 121; [CWNA-109 Study Guide], Chapter 3: Antennas and Accessories, page 115; [Wikipedia], List of WLAN channels.

A POE device that requires 47 W of power should use the 802.3bt specification. This is because 802.3bt is the latest POE standard that supports up to 90 W of power delivery over four pairs of wires in an Ethernet cable. The previous POE standards, such as 802.3af and 802.3at, only support up to 15.4 W and 30 W of power delivery over two pairs of wires in an Ethernet cable, respectively. Therefore, they are not sufficient for powering a device that requires 47 W of power. The 802.11at specification does not exist; it is a typo or confusion with the 802.3at specification. References: CWNA-109 Study Guide, Chapter 8: Wireless LAN Access Points, page 2431