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AD-604 (A) · Internet of Things/Quick Revision Short Notes

Internet of Things (AD-604 (A)) - Unit 1 Short Notes

How unit 1 is examined

This unit covers IoT basics, architecture, M2M, network layout, nodes and gateways, and microcontrollers; the marks come from physical and logical design, ICT enablers, and M2M applied architecture.

IoT definition, Characteristics

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Not asked since 2022</span>

Definition. <mark>The Internet of Things is a network of physical objects embedded with sensors, software and connectivity that collect and exchange data over the Internet with little human intervention.</mark>

Key points.

  1. Every thing has a unique identity, usually an IP address, so it can be found and addressed.
  2. Things sense their surroundings and can act on them through actuators.
  3. Connectivity is ubiquitous and the things are heterogeneous, so many protocols and devices must interoperate.
  4. Devices are resource constrained in power, memory and processing.
  5. Large data volumes are produced, and intelligence is added through analytics and automation.

IoT conceptual and architectural framework, Components of IoT ecosystems

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Not asked since 2022</span>

Definition. <mark>The IoT framework is a layered view in which sensing devices feed a network, the data is processed in the cloud or edge, and applications present the result to the user.</mark>

Key points.

  1. The perception layer holds sensors, actuators and tags that gather data from the physical world.
  2. The network layer carries the data through gateways and protocols such as Wi-Fi, ZigBee and cellular.
  3. The processing layer stores and analyses the data, mostly in the cloud.
  4. The application layer delivers services such as smart home or smart farming.
  5. Ecosystem components are devices, gateway, network, cloud platform, analytics, applications and users.

Physical and logical design of IoT, IoT enablers, Modern day IoT applications

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Medium weight</span>

Definition. <mark>Physical design describes the things, protocols and IoT levels used, while logical design describes the functional blocks, communication models and APIs, without the hardware detail.</mark>

Key points.

  1. Physical design covers the things or devices with sensors, actuators and processors that connect to the network.
  2. The protocols are layered: link (802.11, 802.15.4), network (IPv4, IPv6, 6LoWPAN), transport (TCP, UDP) and application (HTTP, CoAP, MQTT).
  3. IoT levels 1 to 6 are templates that differ in where the data is stored and analysed: local, or on cloud with one or many nodes.
  4. Logical design has six functional blocks: devices, communication, services, management, security and application.
  5. The communication models are request-response, publish-subscribe, push-pull and exclusive pair.
  6. Communication APIs are REST-based (request-response) or WebSocket-based (exclusive pair, full duplex).
  7. ICT trends that enable IoT are ubiquitous connectivity, IPv6 for huge address space, cloud computing, big data analytics, miniaturisation of low-cost sensors, and wireless, mobile and M2M technologies.
  8. Their impact is scalability, heterogeneity and a growing set of applications such as smart homes, healthcare, agriculture, cities and industry.

Diagram. <figure class="ds-fig" style="margin:1.4rem 0;overflow-x:auto"><svg xmlns="http://www.w3.org/2000/svg" id="dsfig-u1-01" viewBox="0 0 467 209" width="467" height="209" role="img" aria-label="Logical design of IoT. Dev device, Com communication, Svc services, App application, Mgt management, Sec security"><style>#dsfig-u1-01 .e{stroke:#454C5A;stroke-width:1.4;fill:none}#dsfig-u1-01 .e.hi{stroke:#2340B8;stroke-width:2.6}#dsfig-u1-01 .n{fill:#FFFFFF;stroke:#16181D;stroke-width:1.4}#dsfig-u1-01 .n.hi{fill:#E3E9FC;stroke:#2340B8;stroke-width:2.2}#dsfig-u1-01 .n.rb-b{fill:#16181D;stroke:#16181D}#dsfig-u1-01 .n.rb-r{fill:#BD3227;stroke:#BD3227}#dsfig-u1-01 text{font-family:"JetBrains Mono",ui-monospace,Menlo,Consolas,monospace;font-size:13px}#dsfig-u1-01 .t{fill:#16181D;font-weight:500}#dsfig-u1-01 .t.inv{fill:#FFFFFF;font-weight:700}#dsfig-u1-01 .kd{stroke:#16181D;stroke-width:1.2}#dsfig-u1-01 .dot{fill:#16181D}#dsfig-u1-01 .ann{fill:#2340B8;font-size:11px;font-weight:700}#dsfig-u1-01 .lbl{fill:#6F7787;font-family:system-ui,-apple-system,sans-serif;font-size:12px;font-weight:700}#dsfig-u1-01 .ptr{fill:#2340B8;font-size:12px;font-weight:700}#dsfig-u1-01 .ah{fill:#454C5A}#dsfig-u1-01 .ah.hi{fill:#2340B8}#dsfig-u1-01 .wl rect{fill:#FFFFFF;stroke:#DCE0E7}#dsfig-u1-01 .wl .t{font-size:12px;font-weight:700}#dsfig-u1-01 .wl.hi rect{fill:#2340B8;stroke:#2340B8}#dsfig-u1-01 .wl.hi .t{fill:#FFFFFF}html.dark #dsfig-u1-01 .e{stroke:#B1B7C3}html.dark #dsfig-u1-01 .e.hi{stroke:#8FA3FF}html.dark #dsfig-u1-01 .n{fill:#161920;stroke:#E6E8ED}html.dark #dsfig-u1-01 .n.hi{fill:#1E2748;stroke:#8FA3FF}html.dark #dsfig-u1-01 .n.rb-b{fill:#E6E8ED;stroke:#E6E8ED}html.dark #dsfig-u1-01 .n.rb-r{fill:#FF7E71;stroke:#FF7E71}html.dark #dsfig-u1-01 .t{fill:#E6E8ED}html.dark #dsfig-u1-01 .t.inv{fill:#0F1115}html.dark #dsfig-u1-01 .kd{stroke:#E6E8ED}html.dark #dsfig-u1-01 .dot{fill:#E6E8ED}html.dark #dsfig-u1-01 .ann{fill:#8FA3FF}html.dark #dsfig-u1-01 .lbl{fill:#858D9C}html.dark #dsfig-u1-01 .ptr{fill:#8FA3FF}html.dark #dsfig-u1-01 .ah{fill:#B1B7C3}html.dark #dsfig-u1-01 .ah.hi{fill:#8FA3FF}html.dark #dsfig-u1-01 .wl rect{fill:#161920;stroke:#2A2E37}html.dark #dsfig-u1-01 .wl.hi rect{fill:#8FA3FF;stroke:#8FA3FF}html.dark #dsfig-u1-01 .wl.hi .t{fill:#0F1115}</style><defs><marker id="ah1" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path class="ah" d="M0,1 L9,5 L0,9 z"/></marker><marker id="ahh1" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse"><path class="ah hi" d="M0,1 L9,5 L0,9 z"/></marker></defs><path class="e" d="M59,40 L148,40" marker-end="url(#ah1)"/><path class="e" d="M188,40 L277,40" marker-end="url(#ah1)"/><path class="e" d="M317,40 L406,40" marker-end="url(#ah1)"/><path class="e" d="M169,150 L169,61" marker-end="url(#ah1)"/><path class="e" d="M182.4,155.6 L283.2,54.8" marker-end="url(#ah1)"/><path class="e" d="M298,150 L298,61" marker-end="url(#ah1)"/><circle class="n" cx="40" cy="40" r="18"/><text class="t" x="40" y="40" dy=".35em" text-anchor="middle">Dev</text><circle class="n" cx="169" cy="40" r="18"/><text class="t" x="169" y="40" dy=".35em" text-anchor="middle">Com</text><circle class="n" cx="298" cy="40" r="18"/><text class="t" x="298" y="40" dy=".35em" text-anchor="middle">Svc</text><circle class="n" cx="427" cy="40" r="18"/><text class="t" x="427" y="40" dy=".35em" text-anchor="middle">App</text><circle class="n" cx="169" cy="169" r="18"/><text class="t" x="169" y="169" dy=".35em" text-anchor="middle">Mgt</text><circle class="n" cx="298" cy="169" r="18"/><text class="t" x="298" y="169" dy=".35em" text-anchor="middle">Sec</text></svg><figcaption style="font-size:.82em;opacity:.72;margin-top:.45rem">Logical design of IoT. Dev device, Com communication, Svc services, App application, Mgt management, Sec security</figcaption></figure>

Answer frame. Open with the IoT definition; for Q2 draw the six-block figure and describe physical design (things, protocols, levels) before logical design (blocks, models, APIs); close with one line that physical design is the hardware and protocols while logical design is the abstract functional structure. For Q3 list the five trends, explain each in one sentence, then give the impact under scalability, heterogeneity and applications.

Asked: [7 marks] (May 2023) What is Internet of things (IoT)? What is physical design and logical design in IoT? Asked: [7 marks] (May 2023) Explain various trend in Information and communication technologies and its impact on IoT.

M2M communications, IoT vs M2M, IoT vs WoT

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Low weight</span>

Definition. <mark>M2M is direct communication between devices, wired or wireless, without human intervention, mostly over cellular or fixed networks for one application.</mark>

Key points.

  1. A reference architecture is generic and reusable, while an applied architecture is that reference architecture adapted to one particular M2M or IoT problem.
  2. Design steps are: state the problem and requirements, select the reference architecture, choose components and protocols for it, map them to the applied architecture, then implement and test.
  3. The architecture domain holds the reusable common services, interfaces and protocols, built once by architects.
  4. The solution domain holds the application-specific devices, data models, integration and deployment, built for each customer.
  5. Partitioning lets the architecture be reused, cuts cost and time, and lets both teams work in parallel. Example: a smart meter solution reuses the common M2M services and adds only meter-specific logic.
  6. IoT vs M2M: IoT is Internet-based, many-to-many and cloud-centred, while M2M is point-to-point, closed and device-centred. IoT vs WoT: WoT reuses web standards (HTTP, REST) as the application layer over IoT.

Answer frame. Open with the difference between reference and applied architecture; give the design steps in order; then explain the two domains and their benefits; close with the smart meter example.

Asked: [7 marks] (May 2023) Describe how a solution is designed for a particular problem by making use applied architecture in M2M/IoT. Also, explain the use of partitioning the architectural work and solution work into two domains.

IoT reference architecture, IoT Network configurations, IoT LAN, IoT WAN

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Not asked since 2022</span>

Definition. <mark>The IoT reference architecture is a generic layered blueprint of devices, network, platform and applications from which specific IoT solutions are derived.</mark>

Key points.

  1. Network configurations include star, mesh and point-to-point links between nodes and gateways.
  2. An IoT LAN covers a small area such as a home or factory and uses Wi-Fi, Ethernet, Bluetooth or ZigBee.
  3. An IoT WAN covers cities or regions and uses cellular, LoRaWAN or satellite links to reach the cloud.
  4. A gateway joins the LAN to the WAN and translates protocols between them.

IoT Node, IoT Gateway, IoT Proxy

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Not asked since 2022</span>

Definition. <mark>An IoT node is a device that senses or acts, a gateway connects nodes to the Internet and translates protocols, and a proxy acts on behalf of a node or client to relay requests.</mark>

Key points.

  1. A node has a sensor or actuator, a microcontroller, a radio and a power source.
  2. A gateway aggregates data, converts protocols such as ZigBee to IP, and can filter data at the edge.
  3. A proxy forwards requests, for example a CoAP-HTTP proxy that lets web clients reach constrained nodes.
  4. Gateways and proxies also give security and caching, so sleeping nodes need not answer every request.

Review of Basic Microcontrollers and interfacing

<span style="display:inline-block;padding:.16em .6em;border:1.5px solid currentColor;border-radius:999px;font-size:.68em;font-weight:700;letter-spacing:.06em;text-transform:uppercase;opacity:.75">Not asked since 2022</span>

Definition. <mark>A microcontroller is a single chip with a CPU, memory and input-output peripherals, used to read sensors and drive actuators.</mark>

Key points.

  1. Common boards are Arduino (AVR) and Raspberry Pi Pico, with ROM or flash, RAM and GPIO pins.
  2. Sensors connect to analog pins through an ADC or to digital pins through GPIO.
  3. Serial interfaces are UART, I2C and SPI, and actuators are driven by GPIO or PWM.
  4. Microcontrollers are low power and low cost, which suits IoT nodes.

Last-minute revision

  • IoT = things with sensors and connectivity exchanging data over the Internet.
  • Characteristics: unique identity, sensing, connectivity, heterogeneity, constrained devices.
  • Layers: perception, network, processing, application.
  • Physical design = things, protocols, IoT levels 1 to 6.
  • Logical design = six functional blocks: devices, communication, services, management, security, application.
  • Communication models: request-response, publish-subscribe, push-pull, exclusive pair.
  • ICT enablers: ubiquitous connectivity, IPv6, cloud, big data, miniaturisation.
  • Applied architecture = reference architecture adapted to one problem.
  • Architecture domain is reusable; solution domain is application-specific.
  • IoT is many-to-many over the Internet; M2M is point-to-point.
  • Gateway links LAN to WAN and translates protocols.

Memory hooks

  • Six logical blocks: "DCS MSA" for Devices, Communication, Services, Management, Security, Application.
  • Four communication models: "RPPE" for Request-response, Publish-subscribe, Push-pull, Exclusive pair.
  • Architecture is built once, solution is built each time.
  • Node senses, gateway translates, proxy relays.

Coverage checklist

  • IoT definition, Characteristics: no past question.
  • IoT conceptual and architectural framework, Components of IoT ecosystems: no past question.
  • Physical and logical design of IoT, IoT enablers, Modern day IoT applications: Q2 (physical and logical design), Q3 (ICT trends and impact).
  • M2M communications, IoT vs M2M, IoT vs WoT: Q1 (applied architecture and partitioning).
  • IoT reference architecture, IoT Network configurations, IoT LAN, IoT WAN: no past question.
  • IoT Node, IoT Gateway, IoT Proxy: no past question.
  • Review of Basic Microcontrollers and interfacing: no past question.
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