Passed Exam Today CWNA-109

To calculate the EIRP at the antenna element, we need to add the transmitter output power, subtract the cable loss, and add the antenna gain. All these values need to be converted to dBm first, if they are not already given in that unit. In this case, we have:

Transmitter output power = 50 mW = 10 log (50) dBm = 16.99 dBm Cable loss = 3 dB Antenna gain = 9 dBi

EIRP = Transmitter output power - Cable loss + Antenna gain EIRP = 16.99 - 3 + 9 EIRP = 22.99 dBm

Rounding up to the nearest integer, we get 23 dBm as the EIRP at the antenna element12. References: CWNA-109 Study Guide, Chapter 2: Radio Frequency Fundamentals, page 92; CWNA-109Study Guide, Chapter 2: Radio Frequency Fundamentals, page 88.

WPA2 (Wi-Fi Protected Access 2) is a security certification program developed by the Wi-Fi Alliance to secure wireless computer networks. It is important to understand the following:

• WPA2 and the 802.11 Standard: While WPA2 is based on elements of the 802.11i amendment to the 802.11 standard, it is not itself a standard but rather a certification to ensure devices comply with certain security criteria, including the correct implementation of CCMP (Counter Mode Cipher Block Chaining Message Authentication Code Protocol) and AES (Advanced Encryption Standard).
• CCMP/AES Implementation: WPA2 enhances the security of wireless networks by using CCMP for encryption, which is based on AES, a robust encryption algorithm. This represents a significant security improvement over WEP (Wired Equivalent Privacy) and WPA (Wi-Fi Protected Access) that used TKIP (Temporal Key Integrity Protocol).
• WPA vs. WPA2: WPA was the interim security enhancement over WEP, utilizing TKIP for encryption. WPA2, however, moved to the more secure AES-based encryption method. Contrary to option C, WPA2 does not enhance security by using TKIP; it uses CCMP/AES.

Therefore, option B correctly describes WPA2 as a certification program ensuring devices properly implement the more secure CCMP/AES encryption methods.

References:

• Wi-Fi Alliance website for WPA2 certification details.
• IEEE 802.11i-2004: Amendment for Enhanced Security.

A pre-design site visit in preparation for a predictive wireless LAN design is essential for gathering physical and environmental data about the site. The key tasks to be performed during such a visit include:

• Evaluating Building Materials: Different materials (concrete, glass, wood, etc.) have varying effects on RF signal propagation. Understanding the materials present helps in accurately predicting how signals will behave within the environment.
• Floor Plan Verification: Ensuring that the floor plan documents are an accurate representation of the actual building layout is crucial. Discrepancies between the floor plans and the physical layout can lead to inaccuracies in the predictive design.

The other options, while potentially valuable in other contexts, are not directly related to preparing for a predictive design:

• Installing APs(option A) for testing co-channel interference is more aligned with an active site survey rather than a pre-design visit for a predictive design.
• Collecting information about security requirements(option B) is important but is not directly related to the physical aspects of the site that would impact a predictive design.
• Testing antenna types(option C) would typically be part of an active site survey or the actual deployment phase, not a pre-design visit for predictive modeling.

Therefore, option D is the correct answer, focusing on evaluating physical aspects crucial for accurate predictive modeling.

References:

• CWNA Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109, by David D. Coleman and David A. Westcott.
• Best practices for conducting pre-design site visits in wireless network planning.

DHCP (Dynamic Host Configuration Protocol) is the network service where option 43 must be configured to allow access points to locate controllers. DHCP is a protocol that allows a device to obtain an IP address and other network configuration parameters from a server. In a wireless controller scenario, the access points can use DHCP to request an IP address from a DHCP server, which can also provide the IP address or hostname of the wireless controller as an option in the DHCP response. Option 43 is a vendor-specific option that can be used to encode custom information for different types of devices. For example, Cisco access points can use option 43 to receive the IP address of the wireless controller from the DHCP server, while Aruba access points can use option 43 to receive the hostname of the wireless controller from the DHCP server. This way, the access points can discover the wireless controller and establish a connection with it. References: 1, Chapter 8, page 309; 2, Section 5.2