CWNA-108 Exam Dumps - Certified Wireless Network Administrator

 iPerf is an open source tool that is designed to perform a throughput test on the WLAN. iPerf is a cross-platform command-line tool that can measure the bandwidth and quality of network links by generating TCP or UDP traffic between two endpoints. iPerf can run as either a server or a client mode, depending on whether it receives or sends traffic. iPerf can also report various metrics of network performance, such as throughput, jitter, packet loss, delay, and TCP window size. To perform a throughput test on the WLAN using iPerf, one device needs to run iPerf in server mode and another device needs to run iPerf in client mode. The devices need to be connected to the same WLAN network and have their IP addresses configured properly. The device running iPerf in client mode needs to specify the IP address of the device running iPerf in server mode as well as other parameters such as protocol, port number, duration, interval, bandwidth limit, packet size, etc. The device running iPerf in server mode will listen for incoming connections from the client device and send back acknowledgments or responses depending on the protocol used. The device running iPerf in client mode will send traffic to the server device according to the specified parameters and measure the network performance. The device running iPerf in client mode will display the results of the throughput test at the end of the test or at regular intervals during the test. The results can show the average, minimum, maximum, and instantaneous throughput of the network link, as well as other metrics such as jitter, packet loss, delay, and TCP window size. References: 1, Chapter 7, page 287; 2, Section 4.3

A common problem that causes this scenario is captive portal issues. A captive portal is a web page that requires users to authenticate or accept terms and conditions before accessing the Internet through a WLAN. A captive portal is often used for guest networks to provide security and control over the network access. A captive portal works by intercepting the user’s web requests and redirecting them to the portal page until the user completes the required action. However, sometimes the captive portal may not work properly due to various reasons, such as browser settings, firewall rules, DNS configuration, or network errors. This can prevent the user from browsing the Internet or seeing the portal page. To troubleshoot captive portal issues, you can try to use a different browser, clear the browser cache and cookies, disable any VPN or proxy settings, manually enter the portal URL, or contact the network administrator. NTP issues, hardware issues, or IP routing issues are not common problems that cause this scenario. References: [CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-107], page 343; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-106], page 333.

Cellular/LTE/5G is the best method for implementing a network backhaul for communications across the Internet in a remote area that is affected by a natural disaster. This is because cellular/LTE/5G networks are wireless and do not depend on physical infrastructure that may be damaged or unavailable in such scenarios. Cellular/LTE/5G networks also offer high-speed data transmission and wide coverage area, which are essential for emergency response operations. 802.11 bridging to the response team headquarters is not feasible because it requires line-of-sight and has limited range. Turning up the output power of the WLAN at the response team headquarters is not effective because it may cause interference and does not guarantee reliable connectivity. Temporary wired DSL is not practical because it requires installing cables and equipment that may not be available or accessible in a remote area. References: CWNA-109 Study Guide, Chapter 7: Wireless LAN Topologies, page 2031

What should be inspected to verify proper configuration is DNS. DNS stands for Domain Name System and is a service that resolves hostnames to IP addresses. In a controller-based AP deployment, DNS can be used to help the AP locate the controller by using a predefined hostname such as CISCO-CAPWAP-CONTROLLER or aruba-master. The AP sends a DNS query for this hostname and receives an IP address of the controller as a response. Therefore, if DNS is not configured properly or if there is no DNS entry for the controller hostname, the AP may not be able to locate the controller. NTP, BOOTP, and AP hosts file are not relevant for this scenario. References: [CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-107], page 374; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-106], page 364.

In addition to coverage analysis results, what should be included in a post-deployment site survey report to ensure WLAN users experience acceptable performance is Capacity analysis results. Capacity analysis is a method of testing the ability of the WLAN to support the expected number and type of users, devices, and applications. Capacity analysis can help to determine the optimal number and placement of access points, the appropriate channel and power settings, the required QoS policies, and the expected throughput and latency levels. Capacity analysis results can help to verify that the WLAN meets the performance requirements and service level agreements (SLAs) of the organization. References: [CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-107], page 548; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-106], page 518.

An IEEE 802.11 amendment is a proposed change or addition to the existing 802.11 standard, which defines the specifications and protocols for wireless LANs. An amendment goes through several stages of development, such as draft, sponsor ballot, and final approval, before it is ratified by the IEEE Standards Association and becomes part of the standard. Until then, it has no official impact on the standard, although some vendors may release products based on draft amendments to gain a competitive edge or to influence the final outcome of the amendment . References: [CWNA-109 Study Guide], Chapter 1: Overview of Wireless Standards, Organizations, and Fundamentals, page 25; [CWNA-108 Study Guide], Chapter 1: Overview of Wireless Standards, Organizations, and Fundamentals, page 23; [IEEE website], IEEE-SA Standards Development Process.

The likely cause of the problem is that the external hard drive is USB 3.0 and is causing a significant increase in the noise floor when in use. USB 3.0 devices are known to generate radio frequency interference (RFI) in the 2.4 GHz band due to their high data transfer rates and harmonics. This RFI can increase the noise floor and degrade the signal-to-noise ratio (SNR) of WLAN devices operating in the same band. This can result in lower data rates, reduced throughput, increased retransmissions, and poor performance. The problem may not occur outside of business hours or on the user’s home network because of different usage patterns or environmental factors. References: [CWNP Certified Wireless Network Administrator Official Study Guide: Exam CWNA-107], page 527; [CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-106], page 497.

The BSSID (Basic Service Set Identifier) is typically mapped to an AP’s MAC address if a single BSS is implemented. The BSSID is a unique identifier that distinguishes one BSS from another within the same RF medium. It is usually derived from the MAC address of the AP’s radio interface, but it can also be manually configured or randomly generated by some vendors. The BSSID is used by client stations to associate with an AP and to send and receive frames within a BSS. References: , Chapter 1, page 24; , Section 1.2