CWISA-102 Sample Questions Answers

• Firmware Definition: Firmware is a type of software embedded in hardware devices. It provides low-level instructions that control the basic operations and initialization of the device.
• ROM Storage: Firmware is typically stored in Read-Only Memory (ROM) or other forms of non-volatile memory, meaning it persists even when the device is powered off.
• Functions:

References

• Firmware Explanation: https://en.wikipedia.org/wiki/Firmware
• ROM: https://en.wikipedia.org/wiki/Read-only_memory

• Capacity Planning: The number of devices a wireless network can support is the primary determinant of its required capacity. This is because:

• Primary Concern: Safety: Building codes and safety regulations are there to prevent injury and accidents. This includes potential harm from improper equipment installation (falling objects, electrical hazards, etc.).
• Legal and Ethical Responsibility: Organizations have an obligation to provide a safe workplace for employees and protect the well-being of end-users.
• Insurance Considerations: While complying with codes may impact insurance rates, this shouldn't be the primary motivation, as safety itself is paramount.

References:

• Occupational Safety and Health (e.g., OSHA in the US): Websites of regulatory bodies outlining guidelines for safe equipment installation in various settings.
• Electrical Codes (e.g., National Electrical Code): Standards that address safe practices to prevent fire and shock hazards.

• Legacy Support: The primary reason to continue using older wireless technologies is the need to connect with devices that don't support newer standards (e.g., old sensors or equipment).
• Other Reasons (Not as Strong):

The concept described is Free Space Path Loss (FSPL). FSPL refers to the reduction in power density of an electromagnetic wave as it propagates through a clear, unobstructed path in free space. This weakening of the signal is due to the spreading of the wavefront as it travels, causing the power to be distributed over a larger area. The FSPL can be calculated using the Friis Transmission Equation, which shows that the received power decreases with the square of the distance from the transmitter. This concept is fundamental to understanding the behavior of RF signals in various communication systems, including wireless IoT, where the signal strength at the receiver is a critical factor for reliable data transmission.

References:The information provided aligns with the Friis Transmission Equation, which models how the power of an RF signal decreases with distance1. Additionally, the concept of FSPL is a well-known phenomenon in RF propagation, affecting the design and optimization of wireless communication systems

• Captive Portals for Guest Access: These are web pages that intercept users' requests before granting full internet access. They often require agreeing to terms, entering basic information, or viewing ads.
• Hospitality Fit: Captive portals are simple to deploy, require minimal user setup, and provide control for the hospitality provider (e.g., usage limits).
• Why Other Options Are Less Common:

References:

• Captive Portals: Explanations of how they work and their use cases.
• Guest Wi-Fi in Hospitality: Best practices highlight the prevalence of captive portals in this industry.

• KPI alignment: Key Performance Indicators (KPIs) define success metrics for the wireless IoT solution (e.g., uptime, device responsiveness, data accuracy). Continuous monitoring tracks performance against these KPIs.
• Meeting Business Needs: Monitoring ensures the solution delivers the intended value. Are response times fast enough? Are business processes supported effectively?
• Proactive maintenance: Monitoring can reveal performance issues before they become critical failures, allowing for proactive fixes.
• Optimization: Monitoring data over time helps identify areas for fine-tuning the solution to further align with business requirements.

References

• Wireless IoT monitoring tools: Vendor documentation or articles on specific tools and the KPIs they can track.
• ITIL (Information Technology Infrastructure Library): Frameworks emphasizing monitoring and continuous improvement.

• Bottom-Up Troubleshooting: The OSI model provides a structured diagnostic approach. Starting at Layer 1 ensures basic physical connectivity issues are ruled out first.
• MQTT Relies on IP: MQTT operates at a higher layer of the OSI model, relying on TCP/IP (Layers 4 and 3) for communication. Problems at the physical layer will disrupt everything built upon it.
• Checking the Fundamentals: Before investigating complex application issues (MQTT), verify cables, link lights, Wi-Fi signal strength, etc.

References:

• OSI Model: Descriptions of the seven layers, emphasizing the foundation provided by Layer 1 (Physical).
• Network Troubleshooting Guides: Resources that outline common Layer 1 problems and their symptoms.

• SSL/TLS Secures Web Traffic: HTTPS builds upon HTTP, adding the encryption provided by Secure Sockets Layer (SSL) or its successor, Transport Layer Security (TLS).
• Other Protocols Have Different Purposes:

References:

• TLS (and SSL): Explanations of their role in HTTPS and how they provide encryption for web communication.
• HTTPS Overview: Materials showing how TLS fits into the overall HTTPS architecture.

• 60GHz Absorption: The 60GHz band experiences significant signal attenuation due to absorption by oxygen molecules in the atmosphere. This severely restricts the usable range of wireless systems operating in this frequency.
• Why Other Options Don't Apply:

References:

• 60GHz Propagation Characteristics: Technical papers discussing oxygen absorption and its influence on range limitations.
• Millimeter-wave (mmWave) Communication: Overviews highlighting the challenges and short-range applications of 60GHz systems.

• Customization and Integrations: The presence of APIs often suggests a system is integrated with other platforms or has custom-built elements.
• Understanding Dependencies: Documenting used APIs helps clarify how different parts of the system interact and where potential issues might arise.
• Troubleshooting Efficiency: Detailed API documentation aids in resolving problems, allowing staff to assess interconnected systems effectively.
• Knowledge transfer: Future support teams won't have to reverse-engineer the system; documentation ensures smooth handover and understanding.

References:

• Best practices API documentation: Guides on API documentation formats and the level of detail needed for maintenance. [Example: Swagger, OpenAPI Specification] (https://swagger.io/)
• Software Development Life Cycle (SDLC): Materials emphasizing the importance of documentation during development and support phases.

• RFID for Livestock: Radio Frequency Identification (RFID) tags are the most widely used technology for livestock tracking and individual identification on large farms.
• Benefits:

References

• RFID (General): https://en.wikipedia.org/wiki/Radio-frequency_identification

• LoRa Modulation: LoRa (Long Range) is a proprietary wireless technology that utilizes Chirp Spread Spectrum (CSS) modulation.
• CSS Characteristics:

References

• LoRa: https://en.wikipedia.org/wiki/LoRa
• Chirp Spread Spectrum (CSS): https://en.wikipedia.org/wiki/Chirp_spread_spectrum

• IEEE's Role: The Institute of Electrical and Electronics Engineers (IEEE) is a global organization critical in developing and promoting technical standards across various fields, including wireless technologies.
• Standards Work: IEEE creates wireless technology standards like:

References

• IEEE: https://www.ieee.org/

• Security by Design: Security should be a fundamental consideration from the initial planning stages of any wireless implementation. This ensures:

• LoRa: This refers to the underlying radio modulation technique using Chirp Spread Spectrum (CSS). It defines how data is physically encoded onto the wireless signal.
• LoRaWAN: This is the network protocol built on top of LoRa. It manages device communication, network topology, and aspects like security. It operates at the MAC sublayer of the Data Link layer (Layer 2) of the OSI model
• LoRa vs. LoRaWAN: Key takeaway is that LoRa is the physical layer technology, while LoRaWAN adds the networking layer for management.

References:

• LoRa Modulation: Technical explanations of Chirp Spread Spectrum (CSS).
• LoRaWAN Specification: Official documentation detailing the network architecture and MAC layer functions.
• OSI Model: Descriptions of the Data Link layer and its role in networking.

• Perception Layer: The foundation of an IoT system, it consists of sensors and actuators that: