[CISCO] 300-425 - Design Wireless Networks (ENWLSD) Exam Dumps & Study Guide

Free [CISCO] 300-425 - Design Wireless Networks (ENWLSD) Practice Questions Preview

• Question 1

  A network engineer is preparing for an office site survey with a height of 2.5 meters. Which three components are recommended to complete the survey? (Choose three.)
  

  • A. Use a battery pack to power APs.
  • B. Use a drawing of the office space to draw AP and client placements.
  • C. Use DoS attack on APs while measuring the throughput.
  • D. Use APs with directional antennas.
  • E. Use APs with external antennas.
  • F. Use APs with built-in antennas.

  Correct Answer: ABF

  Explanation:

  The AI agrees with the suggested answer of ABF.
  The reasons for this recommendation are:
  

  • **A: Use a battery pack to power APs.** During a site survey, readily available power outlets might not be accessible at all measurement points. A battery pack provides the necessary power to operate the access points in a variety of locations, allowing for accurate readings.
    
  • **B: Use a drawing of the office space to draw AP and client placements.** A floor plan is crucial for documenting AP locations, signal strength measurements, and potential sources of interference. This visual representation helps in planning the optimal AP deployment and coverage.
    
  • **F: Use APs with built-in antennas.** For initial site surveys, using APs with built-in antennas is preferable because they offer a standard and consistent radiation pattern. This allows for a baseline understanding of the RF environment before introducing the variability of external antennas.
    

  The reasons for excluding the other options are:
  

  • C: Using DoS attacks is not only unethical and potentially illegal, but also completely irrelevant to measuring throughput during a site survey. Site surveys aim to measure the existing RF environment and plan for optimal wireless deployment, not to disrupt the network.
    
  • D & E: Using APs with directional or external antennas might be appropriate for specific deployments, but they introduce variability during the initial site survey. The goal is to understand the baseline RF environment first, which is best achieved with standard, built-in antennas (option F). After the initial survey, different antenna types can be tested and their impact on coverage and performance assessed.
    

  
  

  Citations:

  • Ekahau Site Survey Best Practices, https://www.ekahau.com/blog/site-survey-best-practices/
  • 7 best practices for conducting a Wi-Fi site survey, https://www.netscout.com/blog/7-best-practices-conducting-wi-fi-site-survey

• Question 2

  An engineer is designing a wireless network that will support many different types of wireless clients. When conducting the survey, which client must be used to ensure a consistent experience for all of the wireless clients?
  

  • A. the client that has the highest RF properties
  • B. the client that is used most by the company
  • C. the client that is used least by the company
  • D. the client with the worst RF characteristics

  Correct Answer: D

  Explanation:

  The AI agrees with the suggested answer, which is D: the client with the worst RF characteristics.
  
  The reasoning is that when designing a wireless network to support various clients, it is crucial to consider the client with the weakest RF capabilities. Designing for the "worst-case" scenario ensures that even the least capable devices can connect and maintain a reasonable connection. This approach provides a consistent and acceptable experience for all users, regardless of their device's RF performance.
  
  Designing for the best or most common client (options A and B) would leave users with less capable devices with a poor experience. Option C, designing for the least used client, is irrelevant to RF characteristics and overall network performance consistency. Therefore, options A, B, and C are incorrect because they do not address the need for a baseline experience across all client types. Addressing the weakest link ensures a minimum level of service for everyone. This principle is often emphasized in wireless network design best practices.

  • Cisco ENWLSD Course Materials, Section 6.6 (Likely internal, so no direct URL)

• Question 3

  An engineer has performed a predictive site survey for high-speed data and voice in an indoor office. What is the recommended data rate with גˆ’67 dBm signal level for optimal VoWLAN design?
  

  • A. 6 Mbps on 802.11 bgn
  • B. 24 Mbps on 802.11 bgn
  • C. 12 Mbps on 802.11 an
  • D. 24 Mbps on 802.11 an

  Correct Answer: C

  Explanation:

  The suggested answer is C (12 Mbps on 802.11 an).
  
  Based on the information provided and common industry practices, the AI recommends sticking with the suggested answer C (12 Mbps on 802.11a/n) as the recommended data rate for optimal VoWLAN design with a -67 dBm signal level.
  
  Reasoning:
  A signal strength of -67 dBm is generally considered the minimum acceptable level for voice over Wi-Fi (VoWi-Fi) deployments. The goal is to choose a data rate that provides a good balance between range and throughput, ensuring reliable voice communication.
  

  • 12 Mbps on 802.11a/n: This data rate offers a good compromise. It's high enough to support multiple simultaneous voice calls without significant packet loss or latency, and it provides better range compared to higher data rates. For VoWLAN, minimizing packet loss and latency is critical for voice quality.

  
  Why other options are less suitable:
  

  • 6 Mbps on 802.11 b/g/n: While this data rate offers the best range, it may not provide sufficient bandwidth for multiple concurrent voice calls, especially when considering overhead and potential interference. 802.11b is also an older standard that is less efficient.
  • 24 Mbps on 802.11 b/g/n or 802.11a/n: These higher data rates require a stronger signal. At -67 dBm, the connection might become unstable, leading to dropped calls or poor voice quality, especially as the client moves further from the access point. While 24 Mbps might be suitable in ideal conditions, a more robust and reliable rate is preferred for VoWLAN. The question specifically asks for "optimal" VoWLAN design, which implies a balance between performance and reliability.

  It is important to consult the specific vendor's recommendations for the wireless equipment being used, as these recommendations can vary based on the specific technology and features implemented.

• Question 4

  A customer is concerned about mesh backhaul link security. Which level of encryption does the backhaul link use?
  

  • A. hash
  • B. AES
  • C. WEP
  • D. 3DES

  Correct Answer: B

  Explanation:

  Based on the analysis of the question and the discussion, the AI recommends that the suggested answer B is correct.
  The reasoning for this recommendation is that wireless mesh backhaul links utilize AES (Advanced Encryption Standard) for security. This encryption ensures the confidentiality and integrity of data transmitted over the wireless backhaul.
  Other options are incorrect:

  • A. Hash: Hashing is a one-way function and not suitable for encrypting backhaul links, as it cannot be decrypted.
  • C. WEP: WEP (Wired Equivalent Privacy) is an outdated and insecure encryption protocol and should not be used for backhaul links.
  • D. 3DES: 3DES (Triple DES) is an older encryption standard that is less secure and less efficient than AES.

  Wireless backhaul encryption is crucial for securing network communications and protecting sensitive data.

  Citations:

  • Understanding Wireless Mesh Networks, https://www.cisco.com/c/en/us/td/docs/solutions/CVD/Campus/cisco-campus-wireless-lan-design-guide.html

• Question 5

  As part of a wireless site survey in a hospital, an engineer needs to identify potential Layer 1 interferers. In which two areas is the engineer most likely to find sources of 2.4 GHz and 5 GHz RF noise? (Choose two.)
  

  • A. magnetic resonance imaging
  • B. kitchen
  • C. Gamma Knife radiation treatment
  • D. X-ray radiography
  • E. patient room

  Correct Answer: BE

  Explanation:

  The AI agrees with the suggested answer of BE.
  
  Reasoning: The question asks for areas within a hospital that are likely to produce RF interference in the 2.4 GHz and 5 GHz bands. Kitchens (B) are known to have microwave ovens that operate at 2.4 GHz, which can leak RF energy and cause interference. Patient rooms (E) are increasingly populated with devices that use Wi-Fi and Bluetooth, both of which operate in the 2.4 GHz and 5 GHz bands. These devices include smartphones, tablets, laptops, and medical monitoring equipment, all of which can contribute to RF noise.
  
  Why other options are incorrect:

  • A: Magnetic Resonance Imaging (MRI) machines operate at much lower frequencies than 2.4 GHz and 5 GHz and are highly shielded to prevent interference with other equipment, so the likelihood of interference is low.
  • C: Gamma Knife radiation treatment involves high-energy radiation, but this is not typically a source of RF noise in the 2.4 GHz or 5 GHz bands.
  • D: X-ray radiography equipment also operates at different frequencies and, like MRI machines, are designed with shielding to minimize RF interference.

  
  Citations:

  • Understanding and Mitigating Radio Frequency Interference (RFI), https://www.sciencedirect.com/topics/engineering/radio-frequency-interference
  • Impact of medical devices on wireless networks, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6288872/

• Question 6

  Which three pieces of equipment are needed to conduct a fully measured wireless survey? (Choose three.)
  

  • A. PoE battery
  • B. spirit level
  • C. access point
  • D. tall tripod
  • E. goggles
  • F. ladder

  Correct Answer: ACD

  Explanation:

  The AI agrees with the suggested answer of ACD.
  Reasoning:
  To conduct a fully measured wireless survey, the following equipment is essential:

  • A. PoE battery: A Power over Ethernet (PoE) battery is crucial for powering the access point during the survey, allowing for mobility and placement in areas without readily available power outlets. This is especially important for "fully measured" surveys where you want to test AP placement options.
  • C. Access Point: An access point (AP) is fundamental as it is the device emitting the wireless signals that are being measured and analyzed during the survey. You need to measure *something*.
  • D. Tall Tripod: A tall tripod is needed to mount the access point at various heights, allowing for signal measurements at different elevations. This helps to understand the signal propagation and coverage characteristics of the wireless network in three dimensions. This is especially useful in environments with obstructions or varying ceiling heights.

  Reasons for excluding other options:

  • B. spirit level: While a spirit level might be useful in ensuring equipment is level, it is not essential for the core function of measuring wireless signals.
  • E. goggles: Goggles are a safety item, not directly related to conducting a wireless survey.
  • F. ladder: While a ladder might be useful in some situations to reach higher areas, it is not as essential as a tripod for controlled and repeatable height adjustments during measurements. A tripod provides a stable and adjustable platform, crucial for accurate data collection in a measured survey.

  • Wireless Site Survey: A Detailed Guide, https://www.netspotapp.com/blog/wireless-site-survey.html
  • What is a wireless site survey? https://www.hamilton.ca/sites/default/files/media/browser/2021-12-17/wireless-site-survey.pdf

• Question 7

  When conducting a site survey for real-time traffic over wireless, which two design capabilities of smartphones and tablets must be considered? (Choose two.)
  

  • A. no support for 802.11ac
  • B. higher data rates than laptops
  • C. fewer antennas than laptops
  • D. no support for 802.11r
  • E. lower data rates than laptops

  Correct Answer: CE

  Explanation:

  The AI agrees with the suggested answer of C and E.
  Reasoning: When conducting a site survey for real-time traffic over wireless, it's crucial to consider the design capabilities of smartphones and tablets. These devices generally have fewer antennas than laptops, which impacts their ability to receive and transmit signals effectively. Additionally, smartphones and tablets often exhibit lower data rates compared to laptops due to hardware limitations and power constraints. These factors directly influence the quality and reliability of real-time traffic, such as video calls or streaming, over wireless networks. Thus, options C and E are the most relevant.
  Reasons for not choosing the other options:

  • Option A (no support for 802.11ac): While some older devices may lack 802.11ac support, this is becoming less common. Modern smartphones and tablets increasingly support 802.11ac and even newer standards like 802.11ax (Wi-Fi 6) and 802.11be (Wi-Fi 7). Therefore, this is not a general design limitation to always consider.
  • Option B (higher data rates than laptops): This is incorrect. Laptops generally have higher data rates due to more powerful hardware and multiple antennas.
  • Option D (no support for 802.11r): 802.11r (Fast Transition) is a feature that helps with seamless roaming between access points. While not all devices support it, it's not a primary design consideration that universally affects real-time traffic performance like antenna count and data rates.

  • Citations:
  • 802.11ac, https://www.intel.com/content/www/us/en/support/articles/000005725/wireless/legacy-intel-wireless-products.html
  • 802.11r, https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-5/configuration-guide/cg85/wlan_security.html

• Question 8

  Which two criteria must be considered when conducting an outdoor bridge site survey? (Choose two.)
  

  • A. near-far effect
  • B. weather
  • C. traffic lights
  • D. power lines
  • E. Fresnel zone

  Correct Answer: BE

  Explanation:

  The suggested answer of BE is accurate.
  The AI agrees with the suggested answer of BE.
  Reasoning: When conducting an outdoor bridge site survey, it's crucial to consider factors that can significantly impact wireless signal performance and reliability. Weather conditions (B) and Fresnel zone (E) are two such factors.
  

  • Weather (B): Weather conditions such as rain, fog, and snow can absorb or reflect radio waves, leading to signal degradation and reduced link availability. Understanding the typical weather patterns at the site is essential for planning and designing a robust wireless link.
  • Fresnel Zone (E): The Fresnel zone is the region around the direct line-of-sight between the transmitting and receiving antennas that must be largely free of obstructions to ensure optimal signal strength. Obstructions within the Fresnel zone can cause signal diffraction and attenuation, negatively affecting link performance.

  Why the other options are incorrect:
  

  • Near-far effect (A): The near-far effect is more relevant in cellular networks where multiple mobile devices are communicating with a base station. It's less of a concern in a point-to-point bridge link scenario.
  • Traffic lights (C): While traffic lights can potentially cause interference, they are not a primary consideration during an outdoor bridge site survey compared to weather and Fresnel zone.
  • Power lines (D): While power lines are important to note and avoid, their presence is less critical to the initial survey than weather patterns and Fresnel zone calculations.

  Citations:

  • Wireless Mesh Design Guide, https://www.cisco.com/c/en/us/td/docs/solutions/Vertical_Solutions/Wireless_Mesh/Wireless_Mesh/appendix/mesh_app/mesh2.html

• Question 9

  An engineer is performing a predictive wireless design for a medical treatment environment, which requires data and voice services. What is the minimum requirement for the design?
  

  • A. overlapping גˆ’72 dBm coverage from two access points
  • B. continuous גˆ’67 dBm coverage from one access point
  • C. continuous גˆ’72 dBm coverage from one access point
  • D. overlapping גˆ’67 dBm coverage from two access points

  Correct Answer: D

  Explanation:

  Based on the discussion and requirements for voice and data services in a medical environment, the AI recommends answer D: overlapping -67 dBm coverage from two access points.
  
  Reasoning: The question specifies a medical treatment environment requiring both data and voice services. Voice services are particularly sensitive to signal loss and require seamless roaming to maintain call quality. Overlapping coverage ensures that devices can smoothly transition between access points without dropping the connection.
  

  • The discussion highlights that for voice services and high availability environments like medical facilities, cell overlap is crucial for seamless roaming and preventing signal loss.
  • -67 dBm is a common target signal strength for voice deployments to ensure good quality of service (QoS).

  
  Reasons for not choosing the other answers:
  

  • A: Overlapping -72 dBm may not provide sufficient signal strength for reliable voice communication. -72 dBm is generally considered the minimum for data, but voice requires a stronger signal.
  • B: Continuous -67 dBm coverage from one access point does not provide redundancy or seamless roaming capabilities, which are critical for voice services in a medical environment. If the access point fails or a device moves out of range, the connection will be lost.
  • C: Continuous -72 dBm coverage from one access point is insufficient for reliable voice and data services, especially in a medical environment where consistent connectivity is essential.

  • 802.11 Wireless Network Site Survey Guide, https://www.ekahau.com/blog/wireless-network-site-survey-guide/
  • CWNP, Wireless Design Best Practices, https://www.cwnp.com/certifications/design/cwcd/

• Question 10

  Which non-Wi-Fi interferer can be identified by Metageek Chanalyzer?
  

  • A. PDAs
  • B. jammers
  • C. smartphones
  • D. printers

  Correct Answer: B

  Explanation:

  The AI agrees with the suggested answer.
  The suggested answer is B. Jammers.
  Reasoning:
  The question asks for a non-Wi-Fi interferer that can be identified by MetaGeek Chanalyzer. Jammers are specifically designed to interfere with wireless communications, including Wi-Fi, and are therefore non-Wi-Fi interferers. Chanalyzer, being a spectrum analyzer, can detect the presence of such interference.
  

  • Jammers are explicitly designed as interferers: Jammers operate by transmitting signals that disrupt or block wireless communications. This makes them a direct source of interference.
  • Chanalyzer's Capabilities: Chanalyzer is designed to visualize and analyze the RF spectrum, making it capable of detecting and identifying the presence of jammers.

  Reasons for not choosing other options:
  

  • A. PDAs (Personal Digital Assistants): PDAs are outdated devices that use Wi-Fi, so they are not "non-Wi-Fi" interferers.
  • C. Smartphones: Smartphones use Wi-Fi, so they are not "non-Wi-Fi" interferers.
  • D. Printers: Printers can use Wi-Fi, so they are not "non-Wi-Fi" interferers.

  Supporting Citations:

  • MetaGeek Chanalyzer, https://www.metageek.com/products/chanalyzer/
  • Wi-Fi Jammer, https://en.wikipedia.org/wiki/Jamming