CWNP CWNA-109 Exam Questions

The IEEE 802.11ax standard, also known as High-Efficiency Wireless (HEW) or simply HE, includes support for operation across multiple frequency bands: 2.4 GHz, 5 GHz, and, with the appropriate regulatory approvals, the 6 GHz band. This makes option D the correct answer. Here's how it compares to the other options:

HE (802.11ax): Introduced as an enhancement over previous standards, 802.11ax is designed to improve efficiency, especially in dense environments. It supports operation in the 2.4 GHz, 5 GHz, and 6 GHz bands (the latter pending regulatory approval in various regions), making it highly versatile and future-proof.

VHT (802.11ac): Very High Throughput, or 802.11ac, operates exclusively in the 5 GHz band. It introduced significant speed improvements over its predecessor (802.11n) but does not support the 2.4 GHz or 6 GHz bands.

HT (802.11n): High Throughput, or 802.11n, supports operation in both the 2.4 GHz and 5 GHz bands. However, it does not include support for the 6 GHz band.

HR/DSSS (802.11b): High-Rate Direct Sequence Spread Spectrum, or 802.11b, operates only in the 2.4 GHz band. It was one of the early Wi-Fi standards and does not support 5 GHz or 6 GHz bands.

Given these distinctions, only 802.11ax (option D) supports operation across all three mentioned bands, aligning with the requirements stated in the question.

IEEE 802.11ax-2021: High-Efficiency Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications.

Understanding the 802.11ax (Wi-Fi 6) standard and its implications for modern wireless networking.

A 5 GHz channel should be used for this AP because channels 1 and 6 are 2.4 GHz channels and they have no impact on the decision. The 5 GHz frequency band offers more non-overlapping channels than the 2.4 GHz frequency band, which reduces interference and improves performance. The 5 GHz frequency band also supports higher data rates and wider channel bandwidths than the 2.4 GHz frequency band, which increases capacity and throughput. The 5 GHz frequency band also has less interference from other devices and sources than the 2.4 GHz frequency band, which enhances reliability and quality of service. Therefore, it is recommended to use the 5 GHz frequency band for WLANs whenever possible. Channels 1 and 6 are two of the three non-overlapping channels in the 2.4 GHz frequency band (the other one is channel 11). They are used by a neighbor network in this scenario, but they do not affect the channel selection for this AP because they operate in a different frequency band than the 5 GHz frequency band. Channel 6 is not always best to use; it depends on the interference and congestion level in the environment. Channel 1 is not best to use because it has a lower frequency than channel 6; frequency does not determine channel quality or performance. Channel 11 is not best to use because it is also a 2.4 GHz channel and it may interfere with channels 1 and 6.Reference:CWNA-109 Study Guide, Chapter 4: Antenna Systems and Radio Frequency (RF) Components, page 113

The IEEE 802.11ax standard, also known as High-Efficiency Wireless (HEW) or simply HE, includes support for operation across multiple frequency bands: 2.4 GHz, 5 GHz, and, with the appropriate regulatory approvals, the 6 GHz band. This makes option D the correct answer. Here's how it compares to the other options:

HE (802.11ax): Introduced as an enhancement over previous standards, 802.11ax is designed to improve efficiency, especially in dense environments. It supports operation in the 2.4 GHz, 5 GHz, and 6 GHz bands (the latter pending regulatory approval in various regions), making it highly versatile and future-proof.

VHT (802.11ac): Very High Throughput, or 802.11ac, operates exclusively in the 5 GHz band. It introduced significant speed improvements over its predecessor (802.11n) but does not support the 2.4 GHz or 6 GHz bands.

HT (802.11n): High Throughput, or 802.11n, supports operation in both the 2.4 GHz and 5 GHz bands. However, it does not include support for the 6 GHz band.

HR/DSSS (802.11b): High-Rate Direct Sequence Spread Spectrum, or 802.11b, operates only in the 2.4 GHz band. It was one of the early Wi-Fi standards and does not support 5 GHz or 6 GHz bands.

Given these distinctions, only 802.11ax (option D) supports operation across all three mentioned bands, aligning with the requirements stated in the question.

IEEE 802.11ax-2021: High-Efficiency Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications.

Understanding the 802.11ax (Wi-Fi 6) standard and its implications for modern wireless networking.

Based on the information given, what can be determined as certainly true about this AP is thatit has 4 radio chains. A radio chain is a hardware component that consists of an antenna, a radio frequency (RF) amplifier, and a transceiver. The number of radio chains indicates how many spatial streams an AP can transmit or receive simultaneously using Multiple Input Multiple Output (MIMO) technology. The notation x:y:z in an AP specification denotes the number of radio chains (x), the number of spatial streams (y), and the number of spatial streams per band (z). Therefore, a tri-band, 4x4:4, Wi-Fi 6, 802.11ax AP has four radio chains in each of its three bands (2.4 GHz, low 5 GHz, and high 5 GHz). It also supports four spatial streams in total and four spatial streams per band. It cannot be determined as certainly true that it supports four channels in each band, UL-MU-MIMO, or uses a modified OpenWRT firmware based on the information given.Reference:[CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 223; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 213.

An immediate concern that you note after hearing this information is thatthe power budget in the edge switches must be carefully planned and monitored based on the number of supported PoE devices. PoE stands for Power over Ethernet and is a technology that allows Ethernet switches to deliver power along with data to devices such as VoIP phones and 802.11 access points. PoE devices are classified into different classes based on their power consumption and output. The edge switches have a limited power budget that determines how many PoE devices they can support simultaneously. If the power budget is exceeded, some PoE devices may not receive enough power or may shut down unexpectedly. Therefore, it is important to plan and monitor the power budget in the edge switches based on the number and class of PoE devices connected to them. Using Ether-channel, placing switches in optimal locations, or avoiding distortion are not immediate concerns related to PoE devices.Reference:[CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 234; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-109], page 224.