Riara University Wireless Networks Past Paper 2024 PDF

UNIVERSITY EXAMINATIONS EXAMINATION FOR JANUARY/APRIL 2023/2024 FOR BACHELOR OF SCIENCE IN COMPUTER SCIENCE AND BACHELOR OF BUSINESS INFORMATION TECHNOLOGY RCS 303: WIRELESS NETWORKS DATE: 12TH APRIL, 2024...

UNIVERSITY EXAMINATIONS EXAMINATION FOR JANUARY/APRIL 2023/2024 FOR BACHELOR OF SCIENCE IN COMPUTER SCIENCE AND BACHELOR OF BUSINESS INFORMATION TECHNOLOGY RCS 303: WIRELESS NETWORKS DATE: 12TH APRIL, 2024 TIME: 2 HOURS GENERAL INSTRUCTIONS: Students are NOT permitted to write on the examination paper during examination period. This is a closed book examination. Text book/Reference books/notes are not permitted. SPECIAL INSTRUCTIONS: This examination paper consists Questions in Section A followed by section B. Answer Question 1 and any Other Two questions. QUESTIONS in ALL Sections should be answered in answer booklet(s). 1. PLEASE start the answer to EACH question on a NEW PAGE. 2. Keep your phone(s) switched off at the front of the examination room. 3. Keep ALL bags and caps at the front of the examination room and DO NOT refer to ANY unauthorized material before or during the course of the examination. 4. ALWAYS show your working. 5. Marks indicated in parenthesis i.e. ( ) will be awarded for clear and logical answers. 6. Write your REGISTRATION No. clearly on the answer booklet(s). 7. For the Questions, write the number of the question on the answer booklet(s) in the order you answered them. 8. DO NOT use your PHONE as a CALCULATOR. 9. YOU are ONLY ALLOWED to leave the exam room 30minutes to the end of the Exam. 10. DO NOT write on the QUESTION PAPER. Use the back of your BOOKLET for any calculations or rough work. Page 1 of 11  SECTION A (COMPULSORY) QUESTION ONE (30 Marks) a) Define the following termininologies as used in satellite communication i) Earth station (A ground-based facility that communicates with satellites) (1 mark) ii) Uplink (The signal sent from an Earth station to a satellite.) (1 mark) iii) Downlink (The signal sent from a satellite to an Earth station) (1 mark) iv) Transponder (A satellite device that receives, amplifies, and retransmits signals) (1 mark) v) Elevation angle (The angle between the horizontal plane and the line of sight to the satellite) (1 mark) b) Enumerate THREE benefits arising from use of spread spectrum (3 marks)  Spread spectrum is a technique that spreads a signal over a wide range of frequencies to reduce interference, noise and eavesdropping, It uses a code to spread the signal, allowing multiple users to share the same frequency securely and efficiently 1. Enhanced security: Spread spectrum makes signals harder to intercept and decode. 2. Resistance to interference: It minimizes the impact of noise and jamming. 3. Efficient bandwidth utilization: Allows multiple users to share the same frequency without interference. c) Identify THREE significant strengths that wireless communication systems have over wired communication systems (3 marks) 1. Mobility: Users can access the network from anywhere without being tied to a physical connection. 2. Ease of installation: No need for cables, making setup faster and simpler. 3. Scalability: Easily accommodates more users and devices without extensive infrastructure changes. Page 2 of 11 d) Describe each of the following IEEE standards: i) 802.11d (2 marks) (allows Wi-Fi devices to operate in different countries by adapting to local regulations, such as frequency and power limits) ii) 802.11e (2 marks) (Enhances Wi-Fi quality of service (QoS) by prioritizing different types of traffic, such as voice, video, and data, to improve performance in multimedia applications) iii) 802.11h (2 marks) (Introduces features like dynamic frequency selection (DFS) and transmit power control (TPC) to reduce interference with other devices and comply with European regulations for 5 GHz Wi-Fi) e) Describe the following three types of antennas and sketch their radiation patterns while indicating areas of application i) Half-wave dipole (2 marks) ( Pattern: Omnidirectional in the horizontal plane (donut-shaped).  Application: FM broadcasting, TV reception, mobile communication.) ii) Quarter-wave dipole (2 marks) ( Pattern: Omnidirectional but slightly less uniform compared to the half-wave dipole. Application: Mobile phones, car radios, handheld radios.) iii) Parabolic (2 marks) ( Pattern: Highly directional with a strong, narrow beam.  Application: Satellite communication, radar, deep-space communication) f) Multiple Access is a phrase commonly used with communication systems. i) Define the term multiple access (1 mark) (Multiple access refers to techniques that allow multiple users or devices to share the same communication channel or frequency band simultaneously without interference) ii) Compare and contrast FDMA and TDMA CDMA. (6 marks) Technique FDMA TDMA CDMA Divides by frequency, Divides by code, users share the Channel Divides by time, each user each user gets a unique same frequency but use different Separation gets a specific time slot. frequency band. codes. Most efficient, as many users Less efficient due to More efficient than FDMA, share the same frequency Efficiency fixed frequency but requires simultaneously with different allocation. synchronization. codes. Susceptible to Can face interference Resistant to interference, as each Interference interference if frequency without proper time slot user has a unique code. bands overlap. synchronization. Page 3 of 11  SECTION B: (ANSWER ANY TWO QUESTIONS) QUESTION TWO (20 Marks) a) The Internet of Things (IoT), also known as the Internet of Everything (IoE), refers to computing devices that are web-enabled and have the capability of sensing, collecting and sending data using sensors, and the communication hardware and processors are embedded within the device. i) With the aid of relevant diagrams, explain in detail how IoT works. (6 marks) 1. Devices/Sensors: IoT devices are embedded with sensors that collect data (e.g., temperature, motion, humidity). These sensors gather data from the environment. 2. Data Transmission: The data collected by the sensors is sent via communication protocols such as Wi-Fi, Bluetooth, Zigbee, or cellular networks to a central system or cloud. 3. Data Processing/Analysis: The data is processed by a central server, cloud computing platform, or edge devices where it is analyzed and interpreted to derive meaningful insights. 4. Action: Based on the analysis, actions or decisions are made automatically or are provided to the user. For example, adjusting a thermostat, turning off lights, or notifying a user about a sensor trigger. 5. User Interface: Users can interact with the IoT system via smartphones, computers, or other devices, either to receive data or to control the devices. [Sensor/Device] --> [Data Transmission] --> [Data Processing/Cloud] --> [Action/Control] | | | (Temperature, motion, etc.) (Wi-Fi, Bluetooth, etc.) (Alert, Notification, Automation) ii) Discuss in detail the IoT application areas and devices. (4 marks)  Smart Homes: IoT enables home automation systems such as smart thermostats (e.g., Nest), smart lights (e.g., Philips Hue), security cameras (e.g., Ring), and voice-controlled assistants (e.g., Alexa, Google Home).  Healthcare: IoT is used in remote patient monitoring, wearable devices (e.g., Fitbit, Apple Watch), medical equipment (e.g., smart inhalers), and emergency response systems (e.g., smart medical alert devices).  Industrial IoT (IIoT): In industries, IoT is used for monitoring machinery, predictive maintenance, asset tracking (e.g., RFID tags), and smart factories (e.g., sensors in manufacturing equipment, robots).  Smart Cities: IoT is applied in smart traffic management (e.g., connected traffic lights), waste management (e.g., smart trash bins), environmental monitoring (e.g., air quality sensors), and street lighting (e.g., smart streetlights) to optimize urban living conditions Page 4 of 11 b) Discuss operating concepts of wireless sensor networks and how they can be used in providing solutions that Kenyans face. (10 marks) 1. Agricultural Monitoring and Precision Farming: o Problem: Kenyan farmers face challenges such as unpredictable weather, crop diseases, and inefficient irrigation systems. o Solution: WSNs can be deployed in farms to monitor soil moisture, temperature, humidity, and crop health. Data from these sensors can help farmers optimize irrigation, detect early signs of pest infestations, and improve crop yields through precision farming techniques. 2. Water Resource Management: o Problem: Water scarcity is a significant issue in many parts of Kenya, especially in rural and arid areas. o Solution: WSNs can be used to monitor water sources, such as rivers, boreholes, and reservoirs, by tracking water levels, quality, and flow rates. This information can help authorities manage water distribution more effectively and ensure that communities have access to safe water. 3. Wildlife Conservation and Poaching Prevention: o Problem: Wildlife conservation is a major challenge in Kenya, with poaching and habitat destruction threatening endangered species. o Solution: WSNs can be used to monitor wildlife movements and detect poaching activities in national parks. Sensors like motion detectors, cameras, and temperature sensors can track animal activity, and alerts can be sent to rangers for immediate response, helping in anti-poaching efforts. 4. Disaster Management and Early Warning Systems: o Problem: Kenya is prone to natural disasters like floods, droughts, and landslides, which often cause significant damage to lives and property. o Solution: WSNs can be used in disaster-prone areas to monitor environmental factors like rainfall, ground movement, and soil moisture. Early warnings can be sent to relevant authorities or local communities to mitigate disaster impact by triggering evacuations or taking preventive actions. 5. Healthcare Monitoring and Rural Health Solutions: o Problem: Access to healthcare in remote and rural areas of Kenya is limited, and there’s a shortage of medical personnel. o Solution: WSNs can be used in healthcare applications for remote patient monitoring. Sensors can track vital signs like heart rate, blood pressure, and oxygen levels in rural areas. The data can be sent to healthcare professionals in urban centers for remote diagnosis, enabling better healthcare delivery in underserved regions. Page 5 of 11 QUESTION THREE (20 Marks) a) Wireless communication is obviously based on the transmission of (radio) signals with a certain frequency content as part of the electromagnetic spectrum. The frequency spectrum is apportioned among users based on the variety of different applications and its suitability for each, competition, regional and global (International Telecommunication Union – radio communication Sector, ITU-R; World Radio communication Conference, WRC) alignment, historical reasons, and other regulatory considerations. Discuss the significant spectrum considerations in relation to access technologies. (6 marks) 1. Frequency Allocation: a. Different frequency bands are assigned for specific applications (e.g., cellular, Wi-Fi). Regulatory bodies like ITU manage this to avoid interference. b. Impact: Access technologies must choose the appropriate frequency for coverage and data rate needs, e.g., low frequencies for coverage and high frequencies for speed. 2. Spectrum Efficiency: a. Efficient use of spectrum maximizes capacity for wireless services. b. Impact: Technologies like 5G use advanced techniques (e.g., MIMO, beamforming) to improve efficiency and handle more users. 3. Regulatory Considerations: a. Spectrum use is governed by regulations to ensure fair access and prevent interference. b. Impact: Access technologies must comply with these rules for global compatibility, as seen with LTE and 5G networks. 4. Competition for Spectrum: a. Spectrum is limited, and different industries or providers compete for it. b. Impact: Technologies like Wi-Fi use unlicensed spectrum to reduce congestion in crowded areas. 5. Propagation Characteristics: a. Lower frequencies provide wider coverage, while higher frequencies offer higher speeds but limited range. b. Impact: Access technologies must use the appropriate frequency for the required coverage and speed, like 5G combining multiple bands. 6. Global Harmonization: a. ITU works on global spectrum harmonization to prevent interference. b. Impact: Harmonized bands ensure global device compatibility, critical for technologies like LTE and 5G. Page 6 of 11 b) There are, of course, a great many things to know about the field of satellite communications. The satellite communications markets and activities are quite dynamic and vary widely around the world and thus require constant monitoring. The issues range from the technology, operations, financial, business aspects and the regulatory environment. Discuss in detail these issues and how they affect the future of satellite communications. (8 marks) 1. Technology: a. Advancements: Innovations like high-throughput satellites (HTS) and low Earth orbit (LEO) satellites are improving bandwidth and reducing latency. b. Impact: These technologies can make satellite services more competitive but are expensive to deploy. 2. Operations: a. Maintenance: Satellites have limited lifespans and require regular maintenance. b. Impact: The high cost of maintenance and managing satellites can limit growth and sustainability. 3. Financial Aspects: a. Cost: Launching and maintaining satellites remains costly. b. Impact: High costs can deter investment, but advancements in reusable rocket technology could reduce expenses. 4. Business Aspects: a. Market Competition: Satellite companies face competition from fiber optics, 5G, and Wi-Fi. b. Impact: Providers must innovate and target niche markets to stay competitive. 5. Regulatory Environment: a. Licensing and Spectrum: Satellite systems require licenses, and spectrum allocation is tightly regulated. b. Impact: Regulatory changes can delay launches and impact operations. 6. Environmental Concerns: a. Space Debris: Increasing satellites raise concerns about space debris and collisions. b. Impact: Effective debris management will be crucial to maintaining operational satellites. 7. Global Connectivity: a. Digital Divide: Satellites help provide internet access to remote areas. b. Impact: They can bridge the digital divide but face competition from 5G and high infrastructure costs. 8. Security: a. Cybersecurity: Satellites are vulnerable to cyberattacks. b. Impact: Strong cybersecurity measures are needed to protect satellite networ Page 7 of 11  c) Discuss in detail Bluetooth as a technology, the security threats surrounding it and how they can be mitigated, and the applications of Bluetooth. (6 marks) 1. Bluetooth Technology: a. Bluetooth is a short-range wireless technology for low-power, low-cost device communication (up to 100 meters) using the 2.4 GHz frequency band. It connects devices like smartphones, headsets, and speakers. 2. Security Threats: a. Eavesdropping: Interception of data being exchanged. b. MITM Attacks: Attackers alter communications between paired devices. c. Bluejacking: Sending unsolicited messages. d. Bluesnarfing: Unauthorized access to device information. e. DoS Attacks: Disrupting Bluetooth connections. 3. Mitigation: a. Pairing with Authentication: Use strong PIN codes or passkeys. b. Encryption: Protects data from eavesdropping. c. Disabling Discoverability: Reduces exposure to unauthorized devices. d. Updates: Keep devices updated with security patches. e. Limit Range: Reduces the risk of unauthorized access. 4. Applications: a. Audio Devices: Wireless headphones and speakers. b. Peripherals: Keyboards, mice, and printers. c. Healthcare: Devices like heart rate monitors and smartwatches. d. Home Automation: Smart locks and thermostats. e. Automotive: Hands-free calling and music streaming in cars. QUESTION FOUR (20 Marks) a) Describe briefly six major transmission functions that are required in long range communications (6 marks) 1. Modulation: Converts the base signal to a higher frequency for long-distance transmission. 2. Amplification: Boosts the signal strength to prevent loss of quality over long distances. 3. Frequency Conversion: Changes the signal’s frequency to avoid interference and optimize transmission. 4. Multiplexing: Combines multiple signals to efficiently use available bandwidth. 5. Error Detection and Correction: Identifies and fixes errors in the signal to maintain data integrity. 6. Demodulation: Converts the received signal back to its original form for accurate data retrieval. Page 8 of 11 b) With aid of simple diagrams, shetch and show the minimum distance between the centers of the cells that use the same frequency in the following cases: i) Frequency re-use for 4-cell re-use pattern (4 marks) A B +---+---+ | 1 | 2 | +---+---+ | 3 | 4 | +---+---+ C D  Minimum Distance: The minimum distance between the centers of cells using the same frequency is the diagonal of the square which is the shortest distance to avoid interference. D =squareroot3×R Where R is the radius of each cell ii) Frequency re-use for 7-cell re-use pattern (4 marks) A +---+ / 1 \ +-----+-----+ / 2 | 3 \ +-----+-----+---+ | 4 | 5 | 6 | +-----+-----+---+ B  Minimum Distance: The minimum distance between the centers of cells using the same frequency is: D=squarerootof7 x R Where R is the radius of each cell. c) Describe the following types of noise in data communication i) Thermal noise (2 mark) Caused by the random movement of electrons in a conductor due to temperature, leading to small voltage changes in all electronic devices. Page 9 of 11  ii) Inter-modulation noise (2 marks) Occurs when signals at different frequencies mix, creating unwanted signals that interfere with communication iii) Cross talk (2 marks) Unwanted signal transfer between communication channels, usually due to electromagnetic interference QUESTION FIVE (20 Marks) a) Discuss THREE major transmission impairments experienced by signals. (3 marks) 1. Attenuation: a. The reduction in signal strength as it travels through a medium. This results in weaker signals that may become difficult to detect over long distances, requiring amplification. 2. Noise: a. Unwanted electrical signals that interfere with the transmitted signal, causing distortion and reducing signal clarity. Common types of noise include thermal noise, interference, and crosstalk. 3. Distortion: a. Occurs when the signal's waveform is altered during transmission, often due to the medium's characteristics. This can cause different frequencies to arrive at different times, leading to signal degradation and loss of information. b) The 802.11 standard states that each conformant wireless LAN must provide nine services. These services are divided into two categories: five distribution services and four station services. The distribution services relate to managing cell membership and interacting with stations outside the cell. In contrast the station services relate to activity within a single cell and deal with station mobility as they enter and leave cells, attaching themselves from base stations. i. Describe each of the five distribution services. (5 marks) 1. Access Control: Manages access to the network, ensuring stations properly communicate with the access point (AP). 2. Association: Manages the process of a station joining the network, ensuring devices can connect to the AP and become part of the network. 3. Disassociation: Manages the process of a station leaving the network, either voluntarily or due to a timeout or error. Page 10 of 11 4. Re-association: Allows a station to move between access points while maintaining connectivity to the network, ensuring continuous service. 5. Distribution: Manages the transfer of data between different networks or cells, ensuring communication across larger network infrastructures. ii. Describe each of the four station services (4 marks) 1. Authentication: Verifies the identity of a station before granting access to the network. 2. De-authentication: Terminates the authentication of a station, preventing further access to the network. 3. Association: Allows a station to connect to a base station or access point, enabling network communication. 4. Re-association: Allows a station to reconnect to a new access point without losing network access, usually when moving between cells. iii. State FOUR rules that apply to data transmission over radio waves (4 marks) 1. Frequency Allocation: Each transmission must use a specific frequency band to avoid interference. 2. Power Limits: Transmission power is regulated to minimize interference with other devices and networks. 3. Modulation Techniques: Data must be modulated into radio waves using appropriate techniques to ensure clear transmission. 4. Signal Strength Monitoring: Transmissions are adjusted based on signal strength to maintain a reliable connection and minimize errors. iv. Explain the concept of data shifting as used in IEEE 802.11b wireless LAN standard (4 marks) Page 11 of 11  UNIVERSITY EXAMINATIONS EXAMINATION FOR MAY/AUGUST 2022/2023 FOR BACHELOR OF SCIENCE IN COMPUTER SCIENCE AND BACHELOR OF BUSINESS INFORMATION TECHNOLOGY COURSE CODE: RCS303 COURSE UNIT: WIRELESS NETWORKS DATE _____________ TIME: 2 HOURS GENERAL INSTRUCTIONS: Students are NOT permitted to write on the examination question paper during examination time. This is a closed book examination. Text book/Reference books/notes are not permitted. SPECIAL INSTRUCTIONS: This examination paper consists Questions in Section A followed by section B. Answer Question 1 and any Other Two questions. QUESTIONS in ALL Sections should be answered in answer booklet(s). 1. PLEASE start the answer to EACH question on a NEW PAGE. 2. Keep your phone(s) switched off at the front of the examination room. 3. Keep ALL bags and caps at the front of the examination room and DO NOT refer to ANY unauthorized material during the course of the examination. 4. ALWAYS show your working. 5. Marks indicated in parenthesis i.e. ( ) will be awarded for clear and logical answers. 6. Write your REGISTRATION No. clearly on the answer booklet(s). 7. For the Questions, write the number of the question on the answer booklet cover page in the order you answered them. 8. DO NOT use your PHONE as a CALCULATOR. 9. YOU are ONLY ALLOWED to leave the exam room 1 hour to the end of the Exam. 10. DO NOT write on the QUESTION PAPER. Use the back of your BOOKLET for any calculations or rough work. 1 of 4 QUESTION ONE (30 MARKS) (a) Describe how each of the following emerging communication theories are driving innovations in the Wireless Networks technologies (Give examples for each): (i) Users’ Choice (3 Marks) Description: Users are empowered to select services and applications that best meet their needs, leading to tailored experiences. Example: Mobile apps allow users to choose specific communication platforms (e.g., WhatsApp, Telegram) based on features like encryption or multimedia capabilities. (ii) Users’ Convenience (3Marks) Description: Innovations focus on enhancing user experience by making access to services easier and more intuitive. Example: Smart home devices that connect via Wi-Fi enable users to control lighting, security, and appliances through a single app, simplifying home management. (iii) Convergence of Technologies (3 Marks) Description: Different technologies are integrated to provide seamless communication and functionality across devices. Example: Smartphones combine features of cameras, GPS, and internet access, allowing users to communicate, navigate, and capture content all in one device. (iv) Backchannel Communications (3 Marks) Description: Facilitates real-time feedback and communication alongside primary interactions, enhancing engagement. Example: During live events, audiences can use social media platforms to share opinions or ask questions, creating a dynamic interaction with speakers or performers. 2 of 4  (v) Artificial Intelligence (3 Marks) Description: AI technologies optimize network performance and user experience through data analysis and automation. Example: AI-driven network management systems can predict traffic patterns and automatically adjust bandwidth allocation, improving service quality and reducing congestion. (b) Discuss the main differences between Wireless Information Networks and Wireless Pervasive Networks (2 Marks) (c) Focus and Purpose: a. Wireless Information Networks: Primarily focus on transmitting data and facilitating communication between devices. Their main goal is to ensure reliable and efficient information exchange (e.g., emails, file transfers). b. Wireless Pervasive Networks: Aim to embed computing and connectivity into everyday environments. They prioritize user interaction and context-awareness, enabling devices to work together seamlessly in various settings (e.g., smart homes, wearable tech). (d) Application Context: a. Wireless Information Networks: Used for specific applications like email and web browsing. b. Wireless Pervasive Networks: Support a wider range of applications, including IoT and smart devices, enhancing user experience through constant connectivity. (e) Based on your understanding of wireless networks description compare and contrast the following two groups of communication technologies: (i) A tethered desktop computer in Small Office Home Office (SOHO) verses your Personal Digital Assistant (PDA) ( 2 Marks) (j) Tethered Desktop Computer: a. Connection: Usually connected via Ethernet or Wi-Fi, providing stable and high-speed internet access. b. Functionality: Designed for intensive tasks like document editing, graphic design, and data analysis, often with larger displays and more powerful hardware. 3 of 4  (k) Personal Digital Assistant (PDA): a. Connection: Typically relies on mobile networks or Wi-Fi for connectivity, offering greater mobility. b. Functionality: Focused on personal organization and communication (e.g., calendar, contacts, emails), with limited processing power compared to desktops. (ii) A laptop in a hotel room verses an Access Point connected to WLAN in legacy building ( 2 Marks)  Laptop in a Hotel Room:  Connection: Connects to the hotel’s Wi-Fi network, providing flexibility for work or leisure while traveling.  Functionality: Serves as a portable computing device, allowing users to perform various tasks like browsing, streaming, and video conferencing.  Access Point Connected to WLAN in a Legacy Building:  Connection: Acts as a hub for multiple devices, extending the wireless network coverage within the building.  Functionality: Provides internet access to various devices (e.g., laptops, smartphones) in the building, ensuring connectivity in areas where signal strength may be weak. (f) Describe FOUR ways in Riara University (RU) my adapt Radio Frequency Identifications Device (RFID) technology within its campus environment ( 4 Marks) (g) Student Attendance Tracking: a. Description: Implement RFID tags in student ID cards to automatically record attendance in lectures and events. This system can streamline attendance management and reduce manual errors. (h) Library Management: a. Description: Use RFID tags on books and other library materials to facilitate easy check-in and check-out processes. This can enhance inventory management and reduce theft or loss of library resources. 4 of 4  (i) Asset Management: a. Description: Equip university equipment (e.g., computers, projectors) with RFID tags to track their location and usage. This helps in maintaining an accurate inventory and ensures that resources are efficiently utilized. (j) Campus Access Control: a. Description: Utilize RFID-enabled access cards for secure entry into restricted areas (e.g., laboratories, administrative offices). This enhances campus security and allows for better monitoring of who accesses sensitive areas. (k) Explain FIVE critical issues that RU should include in its wireless network policy for effective learning and teaching practices (Give examples) (5 Marks) (l) Network Security: a. Description: Implement strong security protocols to protect sensitive data and user privacy. b. Example: Use WPA3 encryption for Wi-Fi networks and require multi- factor authentication for accessing university systems to prevent unauthorized access. (m) Bandwidth Management: a. Description: Establish policies to ensure fair distribution of bandwidth among users, especially during peak usage times. b. Example: Prioritize educational applications and essential services (e.g., online classes, learning management systems) over non-essential applications (e.g., streaming services) to maintain a smooth learning experience. (n) Acceptable Use Policy: a. Description: Define acceptable and prohibited activities on the university's wireless network to promote responsible use. b. Example: Prohibit illegal downloading, hacking, or accessing inappropriate content, and outline consequences for violations to maintain a safe learning environment. (o) Device Management: a. Description: Create guidelines for connecting personal devices to the university network to minimize security risks. 5 of 4  b. Example: Require that all devices connect through a secure portal and have up-to-date antivirus software before accessing the network. (p) Technical Support and Training: a. Description: Provide adequate support and training for students and staff to effectively use wireless technology in their learning and teaching practices. b. Example: Offer workshops on using learning management systems and troubleshooting connectivity issues, ensuring that users can maximize the benefits of the wireless network. QUESTION TWO (20 Marks) (a) Explain how a smartphone user who arrives in an SGR coach at railway station that s/he has never visited before is capable of using the wireless networking with the same device IP Address (5 Marks) (b) Dynamic IP Address Assignment: a. When the user connects to the Wi-Fi network on the train, the network's DHCP (Dynamic Host Configuration Protocol) server assigns a temporary IP address to the device. This IP address is valid only for the duration of the connection. The user’s device can maintain the same local IP address within that specific network. (c) Mobile Network Roaming: a. If the user is not connected to the train’s Wi-Fi and is using their mobile data, the smartphone connects to the mobile network of the service provider. Mobile networks can use the same public IP address for the user’s device when roaming, allowing continuity in connection. (d) VPN Usage: a. If the user employs a Virtual Private Network (VPN) on their smartphone, the VPN can provide a consistent external IP address regardless of the network being used. This means that even when switching networks (from home Wi- Fi to train Wi-Fi), the user appears to have the same IP address as far as the VPN server is concerned. (e) Session Persistence: a. Applications that rely on session persistence (like email clients or social media apps) can maintain user sessions even if the IP address changes. The applications use authentication tokens stored on the device, allowing seamless access without needing to log in again. 6 of 4  (f) Network Configuration: a. Some advanced network configurations allow for seamless transitions between different networks. For example, if the SGR coach has a setup that maintains a consistent connection through a centralized management system, the user can experience continuity in their network connection. (b) Explain what may happen to your device MAC address and the IP address when your wireless device is moved from one WLAN location to another WLAN location at RU (5 Marks). 1. MAC Address:  Unchanged: The MAC (Media Access Control) address is a unique identifier assigned to the network interface of the device. It remains constant regardless of the WLAN location. When moving from one WLAN to another, the MAC address does not change. 2. IP Address Assignment:  Dynamic Change: When the device connects to a new WLAN, it will typically receive a new IP address. This is because most WLANs use DHCP (Dynamic Host Configuration Protocol) to assign IP addresses dynamically.  Local Network Scope: The new IP address assigned will be local to the new WLAN, meaning it will be different from the IP address assigned in the previous WLAN. 3. Network Configuration:  Subnet Change: Each WLAN may operate on a different subnet. When switching networks, the device will obtain an IP address that corresponds to the subnet of the new WLAN. 4. Connection Process:  Re-authentication: Upon connecting to the new WLAN, the device may need to re- authenticate, especially if the WLAN has security protocols (like WPA2) that require credentials. 5. Session Continuity:  Potential Disruption: Moving between WLANs may disrupt ongoing sessions (e.g., video calls, streaming) due to the change in IP address, although applications using persistent sessions may recover without requiring a re-login. 7 of 4  (c) CASE STUDY 2.1: When the smartphone user (a) arrives at the ‘new’ railway station s/he would be able to determine how far away his host friend who is outside that SGR railway station would be. Discuss how the smartphone user and his friend could share their respective locations without entering the station’s name or attributes. (10 Marks) 1. GPS and Location Services:  Functionality: Both the smartphone user and their friend can enable GPS on their devices, which allows them to obtain precise geographic coordinates (latitude and longitude).  Implementation: By using location services, each person can get their current coordinates without needing to input any station-related information. 2. Location Sharing via Messaging Apps:  Functionality: Many messaging applications (e.g., WhatsApp, Google Maps, or Facebook Messenger) have built-in location-sharing features.  Implementation: The smartphone user can share their live location through the app, allowing the friend to see exactly where they are without needing to know the station's name. 3. Mapping Applications:  Functionality: Applications like Google Maps or Apple Maps allow users to share their locations directly.  Implementation: The smartphone user can open the mapping app, tap on the "Share Location" feature, and send a link to their friend. The friend can then view the shared location on their own map. 4. QR Code Location Sharing:  Functionality: Some apps generate QR codes containing location data.  Implementation: The smartphone user can generate a QR code with their current location, which the friend can scan to receive the location details instantly. Voice Assistants: 5. Functionality: Voice-activated assistants (e.g., Siri, Google Assistant) can help share locations verbally. Implementation: The smartphone user can ask the assistant to share their location with their friend, who can receive the coordinates or a map link 8 of 4  QUESTION THREE (20 Marks) (a) Using a sketch diagram, define the role and importance of each layer in a five layers Open Systems Interconnection (OSI) protocol suite for Wireless Network (10 Marks) 1. Application Layer:  Role: Provides network services directly to end-users. It facilitates communication between software applications.  Importance: Ensures that user applications (like web browsers, email clients) can communicate over the network, enabling functionalities like file transfer and remote login. 2. Presentation Layer:  Role: Translates data between the application layer and the network. It handles data encoding, encryption, and compression.  Importance: Ensures that data is presented in a readable format for the application layer, allowing interoperability between different data formats and ensuring secure communication. 3. Session Layer:  Role: Manages sessions or connections between applications. It establishes, maintains, and terminates connections.  Importance: Facilitates dialogue control and synchronization between applications, ensuring that data is properly organized and managed during communication sessions. 4. Transport Layer:  Role: Provides reliable or unreliable delivery of data segments between hosts, using protocols like TCP and UDP.  Importance: Ensures error recovery, flow control, and segmentation of data, which is crucial for maintaining reliable communication in wireless networks where data loss can occur. 5. Network Layer:  Role: Manages routing of data packets across the network. It determines the best path for data transmission.  Importance: Handles logical addressing and routing, enabling devices to communicate across different networks and ensuring efficient data delivery, especially in wireless environments with variable connectivity. 9 of 4  (b) For each of the Wireless Networks OSI layer discuss its main applications: the physical layer address, network layer address, and domain name layer at RU (Give examples) (6 Marks) 1. Physical Layer:  Application: Handles the transmission of raw data over physical mediums (like cables and antennas).  Address: Uses physical addresses (MAC addresses) to identify devices on the same network.  Examples:  Wi-Fi: Standards like IEEE 802.11 allow devices to connect wirelessly.  Signal Transmission: Data is transmitted over radio waves using antennas. 2. Network Layer:  Application: Routes data packets between devices across different networks.  Address: Uses logical addresses (IP addresses) for device identification.  Examples:  IP Addressing: Devices at RU are assigned IP addresses (e.g., 192.168.1.10).  Routing: Protocols like IP help route packets within the university’s network. 3. Domain Name System (DNS) Layer:  Application: Translates domain names into IP addresses for easy access.  Address: Works with domain names (e.g., www.ru.ac.ke) instead of specific addresses.  Examples:  Website Access: Resolves www.ru.ac.ke to an IP address for the university's website.  Email Services: Resolves email addresses like [email protected] to the corresponding server's IP. (c) Define the applications for UDP and TCP Protocols in wireless packets routing (4 Marks) 1. User Datagram Protocol (UDP):  Application: UDP is a connectionless protocol that allows for fast, efficient data transmission without establishing a connection.  Use Cases: 10 of 4  Streaming Media: Ideal for applications like video and audio streaming (e.g., YouTube, Spotify) where speed is crucial, and some data loss is acceptable.  Online Gaming: Used in multiplayer games where real-time performance is more important than perfect accuracy, allowing for quick updates of player positions.  VoIP (Voice over Internet Protocol): Enables real-time voice communication (e.g., Skype, Zoom) where low latency is essential. 2. Transmission Control Protocol (TCP):  Application: TCP is a connection-oriented protocol that ensures reliable data transmission through error checking and data recovery.  Use Cases:  Web Browsing: Used for loading web pages (HTTP/HTTPS) where reliable delivery of data is critical.  File Transfers: Protocols like FTP (File Transfer Protocol) rely on TCP to ensure files are transferred accurately and completely.  Email Transmission: Email protocols (e.g., SMTP, IMAP) use TCP to ensure that messages are sent and received reliably. QUESTION FOUR (20 Marks) (a) Discuss FIVE ways in which an employer may track his employee device’s whereabout while engaging him in the Bring Your Own Device (BYOD) wireless networks (10 Marks) (b) Mobile Device Management (MDM) Solutions: a. Description: MDM software allows employers to manage and secure employee devices connected to the company network. b. Functionality: It can track device location, enforce security policies, and remotely wipe data if a device is lost or stolen. (c) Geolocation Services: a. Description: Employers can utilize GPS and Wi-Fi triangulation to determine the physical location of employee devices. b. Functionality: This allows for real-time tracking of devices, ensuring employees are within designated areas (e.g., office premises). (d) Network Monitoring Tools: a. Description: Tools that monitor network traffic can help track devices connected to the company’s wireless network. 11 of 4  b. Functionality: These tools can log device connections, data usage, and time spent on the network, providing insights into employee activity.. (e) Access Control Policies: a. Description: Implementing strict access control policies can help track which devices access specific company resources. b. Functionality: By requiring authentication and logging access attempts, employers can determine which devices are used for work-related tasks.. (f) Employee Agreements and Monitoring Software: a. Description: Employers can require employees to sign agreements that outline the monitoring of their devices. b. Functionality: Monitoring software can track app usage, internet activity, and device location, ensuring compliance with company policies. (g) CASE STUDY 4.1: On August 6, 2022, Moja Expressway Company opened a modern Nairobi Expressway motorway that uses three modes of payment: Electronic Toll Collection (ETC) service, Manual Toll Collection (MTC) card and on Cash basis. Figure 4.1 below is a sample of a ticket recently obtained from one of the toll stations along the new road. Describe FIVE ways in which the company have adopted the wireless network technologies (10 Marks) Figure 4.1 Nairobi Expressway Payment Voucher 12 of 4 1. Electronic Toll Collection (ETC) System:  Description: The implementation of an ETC system allows vehicles to pass through toll booths without stopping. This system uses RFID (Radio Frequency Identification) technology.  Functionality: Vehicles equipped with RFID tags are automatically detected and charged as they pass through the toll gates, enhancing traffic flow and reducing congestion. 2. Mobile Payment Solutions:  Description: The company likely offers mobile payment options for toll fees, enabling users to pay via mobile applications.  Functionality: This allows drivers to pay for tolls using their smartphones, facilitating quick and convenient transactions without needing cash or physical cards. 3. Wireless Communication for Toll Booths:  Description: Toll booths are equipped with wireless communication systems that connect to a central management system.  Functionality: This enables real-time data transmission regarding vehicle passage, payment status, and system alerts, ensuring efficient operation and monitoring. 4. Data Analytics and Monitoring:  Description: Wireless technologies facilitate the collection of data from various points along the expressway.  Functionality: The company can monitor traffic patterns, payment methods, and peak usage times, allowing for better management and optimization of toll operations. 5. Customer Support and Notifications:  Description: The use of SMS and mobile notifications keeps users informed about their account status, toll charges, and promotions.  Functionality: Customers can receive alerts on their mobile devices regarding low balances, payment confirmations, or changes in toll rates, enhancing user experience and engagement. 13 of 4  QUESTION FIVE (20 Marks) (a) Figure 5.1 is a Riara University (RU) flagship project concept for connecting wireless network Access Points (AP1 and AP2) on top of two buildings on each side of Raila Odinga Road. Discuss THREE challenges you may face when implementing this new project. Give to mitigation procedures any two you have discussed (10 Marks) AP 1 AP 2 Satellite Main Campus Campus Figure 5.1 New RU Wireless Network Project Design 1. Signal Interference:  Description: Wireless signals can be affected by physical obstacles (like buildings and trees) and electronic devices (like microwaves and cordless phones), leading to reduced network performance.  Mitigation Procedures:  Site Survey: Conduct a thorough site survey to identify potential sources of interference and optimal locations for Access Points (APs).  Frequency Management: Utilize dual-band routers and configure APs to operate on less congested frequencies to minimize interference. 14 of 4 2. Coverage Gaps:  Description: Ensuring complete coverage across the area can be challenging, especially in urban environments with varying building heights and layouts.  Mitigation Procedures:  Strategic Placement: Carefully plan the placement of APs to ensure overlapping coverage areas, thereby minimizing dead zones.  Use of Repeaters or Mesh Networks: Implement repeaters or a mesh network system to extend coverage and improve connectivity in hard-to-reach areas. 3. Security Risks:  Description: Wireless networks are vulnerable to unauthorized access and data breaches, which can compromise sensitive information.  Mitigation Procedures:  Strong Encryption: Use strong encryption protocols (like WPA3) to secure wireless communications and protect user data.  Regular Security Audits: Conduct regular security assessments and updates to identify vulnerabilities and ensure that security measures are up-to-date. 15 of 4  (b) One disadvantage of an IP broadcast subnetting in a wireless network is the capacity wastage when multiple hosts attempt to access the channel at the same time. Discuss how it is possible for a sequence of packets transmitted through a wide area wireless network such as GSM 4.5 G to arrive at their destination in an order that differs from that in which they were sent in comparison to a local WLAN network (10 Marks) In both wide area wireless networks (like GSM 4.5G) and local WLANs, packets can arrive out of order due to various factors. However, the reasons and mechanisms behind this behavior differ significantly between the two types of networks. Factors Leading to Out-of-Order Packet Delivery 1. Network Architecture:  Wide Area Networks (WAN): In networks like GSM 4.5G, data is transmitted over longer distances through various intermediate nodes (e.g., base stations, routers). Each node may have different processing times, leading to packets taking different paths and arriving at different times.  Local Area Networks (LAN): In a WLAN, packets typically travel shorter distances within a more controlled environment. The fewer hops usually result in more consistent delivery times. 2. Variable Latency:  WAN: The latency in a wide area network can vary significantly due to factors such as congestion, routing changes, and signal degradation over long distances. Packets may be queued at different points, causing variations in arrival times.  LAN: In a local WLAN, latency is generally lower and more consistent, leading to a higher likelihood of packets arriving in the order they were sent. 3. Channel Access Methods:  WAN: GSM and similar technologies use complex channel access methods, including time division and frequency division, which can introduce delays as packets wait for their turn to be transmitted.  LAN: WLANs often use CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance), which helps manage how packets are sent but can still lead to collisions and retransmissions, albeit in a more predictable manner. 4. Packet Fragmentation and Reassembly:  WAN: Larger packets may be fragmented into smaller ones for transmission, and if these fragments take different routes or experience varying delays, they can arrive out of order.  LAN: Fragmentation can also occur in WLANs, but the shorter distances and fewer routing nodes generally lead to more synchronized arrival of fragments.  16 of 4 5. Error Handling and Retransmission:  WAN: In wide area networks, error handling mechanisms may cause packets to be retransmitted if they are lost or corrupted. If a packet is delayed and then retransmitted, it may arrive later than other packets that were sent afterward.  LAN: While WLANs also handle errors, the lower latency and more reliable connections typically result in fewer retransmissions and better order preservation. 17 of 4