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CS-801 · Internet of Things/Quick Revision Short Notes

Internet of Things (CS-801) - Unit 1 Short Notes

How unit 1 is examined

This unit covers what IoT is, its architectures and design levels, M2M, network building blocks and microcontrollers; physical and logical design and microcontrollers carry the most marks, then IoT vs M2M and the architectural framework.

IoT definition

<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, so they can be monitored and controlled with little or no human intervention.</mark>

Key points.

  1. Each "thing" has a unique identity (an IP address or ID), so it can be addressed on the network.
  2. Things sense the environment, send the data onward, and can act on the result through actuators.
  3. Data is processed locally or in the cloud, and the outcome drives decisions or automation.
  4. Examples are a smart thermostat, a wearable fitness band and a connected vehicle.

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. The characteristics are the properties that separate an IoT system from an ordinary network of computers.

Key points.

  1. Connectivity: every object can reach the network and other objects.
  2. Intelligence and autonomous behaviour: objects sense, decide and act without a person.
  3. Heterogeneity: devices differ in hardware, platform and protocol, yet must interoperate.
  4. Scalability: billions of devices and their data must be handled as the system grows.
  5. Dynamic changes: devices join, leave, sleep and move, so the network reconfigures itself.
  6. Security and safety: the connected physical world needs protection of data, devices and people.

IoT conceptual and architectural framework

<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. The conceptual framework is the vision of connecting everyday things so they interact intelligently; the architectural framework organises that vision into layers. <mark>A layered IoT architecture has a perception layer that senses, a network layer that transmits, a middleware layer that processes and an application layer that serves the user.</mark>

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 80 338" width="80" height="338" role="img" aria-label="Four-layer IoT architecture: Per = perception layer, Net = network layer, Mid = middleware layer, App = application layer"><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="M40,61 L40,105" marker-end="url(#ah1)" marker-start="url(#ah1)"/><path class="e" d="M40,147 L40,191" marker-end="url(#ah1)" marker-start="url(#ah1)"/><path class="e" d="M40,233 L40,277" marker-end="url(#ah1)" marker-start="url(#ah1)"/><circle class="n" cx="40" cy="40" r="18"/><text class="t" x="40" y="40" dy=".35em" text-anchor="middle">App</text><circle class="n" cx="40" cy="126" r="18"/><text class="t" x="40" y="126" dy=".35em" text-anchor="middle">Mid</text><circle class="n" cx="40" cy="212" r="18"/><text class="t" x="40" y="212" dy=".35em" text-anchor="middle">Net</text><circle class="n" cx="40" cy="298" r="18"/><text class="t" x="40" y="298" dy=".35em" text-anchor="middle">Per</text></svg><figcaption style="font-size:.82em;opacity:.72;margin-top:.45rem">Four-layer IoT architecture: Per = perception layer, Net = network layer, Mid = middleware layer, App = application layer</figcaption></figure>

Key points.

  1. The perception layer holds sensors, actuators, RFID tags and embedded devices that collect data and act on the physical world.
  2. The network layer carries data over WiFi, Bluetooth, ZigBee, 6LoWPAN or cellular links through gateways.
  3. The middleware (processing) layer stores data and analyses it, often in the cloud, and hides device differences from applications.
  4. The application layer delivers services such as smart home, health monitoring or smart farming to the user.
  5. It gives interoperability, scalability and autonomous processing.
  6. Its significance in intelligent systems is automation, faster decisions and better efficiency, for example a smart grid that balances load by itself.

Answer frame. Open with the definition of the framework; draw the layered figure with a device example beside each layer; develop points 1-4 layer by layer, then point 6; close with point 7 and one example.

Asked: [7 marks] (Dec 2024, May 2026) Explain IoT architectural framework and characteristics. / Explain the conceptual and architectural framework of IoT and discuss its significance in intelligent systems.

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">Low weight</span>

Definition. <mark>The IoT ecosystem is the set of devices, connectivity, platform, analytics and applications that together turn raw sensor data into useful action.</mark>

Key points.

  1. Devices (sensors and actuators) capture data and carry out commands.
  2. Connectivity (gateways and networks) moves the data using protocols such as MQTT, CoAP and HTTP.
  3. The IoT platform in the cloud stores data, manages devices and provides APIs.
  4. Analytics turns the data into insight, from simple rules to machine learning.
  5. Applications present results and let the user control devices; security runs through every part.

Diagram. <figure class="ds-fig" style="margin:1.4rem 0;overflow-x:auto"><svg xmlns="http://www.w3.org/2000/svg" id="dsfig-u1-02" viewBox="0 0 596 80" width="596" height="80" role="img" aria-label="IoT ecosystem: devices, gateway (connectivity), cloud platform, analytics, applications"><style>#dsfig-u1-02 .e{stroke:#454C5A;stroke-width:1.4;fill:none}#dsfig-u1-02 .e.hi{stroke:#2340B8;stroke-width:2.6}#dsfig-u1-02 .n{fill:#FFFFFF;stroke:#16181D;stroke-width:1.4}#dsfig-u1-02 .n.hi{fill:#E3E9FC;stroke:#2340B8;stroke-width:2.2}#dsfig-u1-02 .n.rb-b{fill:#16181D;stroke:#16181D}#dsfig-u1-02 .n.rb-r{fill:#BD3227;stroke:#BD3227}#dsfig-u1-02 text{font-family:"JetBrains Mono",ui-monospace,Menlo,Consolas,monospace;font-size:13px}#dsfig-u1-02 .t{fill:#16181D;font-weight:500}#dsfig-u1-02 .t.inv{fill:#FFFFFF;font-weight:700}#dsfig-u1-02 .kd{stroke:#16181D;stroke-width:1.2}#dsfig-u1-02 .dot{fill:#16181D}#dsfig-u1-02 .ann{fill:#2340B8;font-size:11px;font-weight:700}#dsfig-u1-02 .lbl{fill:#6F7787;font-family:system-ui,-apple-system,sans-serif;font-size:12px;font-weight:700}#dsfig-u1-02 .ptr{fill:#2340B8;font-size:12px;font-weight:700}#dsfig-u1-02 .ah{fill:#454C5A}#dsfig-u1-02 .ah.hi{fill:#2340B8}#dsfig-u1-02 .wl rect{fill:#FFFFFF;stroke:#DCE0E7}#dsfig-u1-02 .wl .t{font-size:12px;font-weight:700}#dsfig-u1-02 .wl.hi rect{fill:#2340B8;stroke:#2340B8}#dsfig-u1-02 .wl.hi .t{fill:#FFFFFF}html.dark #dsfig-u1-02 .e{stroke:#B1B7C3}html.dark #dsfig-u1-02 .e.hi{stroke:#8FA3FF}html.dark #dsfig-u1-02 .n{fill:#161920;stroke:#E6E8ED}html.dark #dsfig-u1-02 .n.hi{fill:#1E2748;stroke:#8FA3FF}html.dark #dsfig-u1-02 .n.rb-b{fill:#E6E8ED;stroke:#E6E8ED}html.dark #dsfig-u1-02 .n.rb-r{fill:#FF7E71;stroke:#FF7E71}html.dark #dsfig-u1-02 .t{fill:#E6E8ED}html.dark #dsfig-u1-02 .t.inv{fill:#0F1115}html.dark #dsfig-u1-02 .kd{stroke:#E6E8ED}html.dark #dsfig-u1-02 .dot{fill:#E6E8ED}html.dark #dsfig-u1-02 .ann{fill:#8FA3FF}html.dark #dsfig-u1-02 .lbl{fill:#858D9C}html.dark #dsfig-u1-02 .ptr{fill:#8FA3FF}html.dark #dsfig-u1-02 .ah{fill:#B1B7C3}html.dark #dsfig-u1-02 .ah.hi{fill:#8FA3FF}html.dark #dsfig-u1-02 .wl rect{fill:#161920;stroke:#2A2E37}html.dark #dsfig-u1-02 .wl.hi rect{fill:#8FA3FF;stroke:#8FA3FF}html.dark #dsfig-u1-02 .wl.hi .t{fill:#0F1115}</style><defs><marker id="ah2" 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="ahh2" 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(#ah2)"/><path class="e" d="M188,40 L277,40" marker-end="url(#ah2)"/><path class="e" d="M317,40 L406,40" marker-end="url(#ah2)"/><path class="e" d="M446,40 L535,40" marker-end="url(#ah2)"/><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">GW</text><circle class="n" cx="298" cy="40" r="18"/><text class="t" x="298" y="40" dy=".35em" text-anchor="middle">Cld</text><circle class="n" cx="427" cy="40" r="18"/><text class="t" x="427" y="40" dy=".35em" text-anchor="middle">Ana</text><circle class="n" cx="556" cy="40" r="18"/><text class="t" x="556" y="40" dy=".35em" text-anchor="middle">App</text></svg><figcaption style="font-size:.82em;opacity:.72;margin-top:.45rem">IoT ecosystem: devices, gateway (connectivity), cloud platform, analytics, applications</figcaption></figure>

Asked: [7 marks] (May 2023) What is IoT? Describe in detail about IoT ecosystem.

Physical and logical design of IoT

<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">High weight</span>

Definition. <mark>Physical design describes the actual devices, protocols and hardware of an IoT system, while logical design describes its abstract functional blocks, communication models and data flow without tying them to hardware.</mark>

Comparison.

Aspect Physical design Logical design
Meaning Concrete devices and protocols Abstract functional blocks and interactions
Contents Things, gateway, cloud, network Device, communication, service, management, security, application blocks; APIs
Protocols Link, network, transport, application protocols in use Communication models (request-response, publish-subscribe and so on)
Example: smart home Temperature sensor, ESP32, router, cloud server Sensing block, communication block, REST API, alert service

Communication models.

  1. Request-response: the client sends a request and the server replies; it is stateless, for example HTTP and CoAP.
  2. Publish-subscribe: publishers send to topics on a broker, which forwards to subscribers, so they are decoupled; example MQTT.
  3. Push-pull: producers push data into a queue and consumers pull from it at their own rate, which decouples speeds.
  4. Exclusive pair: a persistent two-way connection between one client and one server that stays open; example WebSocket.

<figure class="ds-fig" style="margin:1.4rem 0;overflow-x:auto"><svg xmlns="http://www.w3.org/2000/svg" id="dsfig-u1-03" viewBox="0 0 639 80" width="639" height="80" role="img" aria-label="Left: request-response (C client, S server). Right: publish-subscribe (P publisher, B broker, U subscriber)"><style>#dsfig-u1-03 .e{stroke:#454C5A;stroke-width:1.4;fill:none}#dsfig-u1-03 .e.hi{stroke:#2340B8;stroke-width:2.6}#dsfig-u1-03 .n{fill:#FFFFFF;stroke:#16181D;stroke-width:1.4}#dsfig-u1-03 .n.hi{fill:#E3E9FC;stroke:#2340B8;stroke-width:2.2}#dsfig-u1-03 .n.rb-b{fill:#16181D;stroke:#16181D}#dsfig-u1-03 .n.rb-r{fill:#BD3227;stroke:#BD3227}#dsfig-u1-03 text{font-family:"JetBrains Mono",ui-monospace,Menlo,Consolas,monospace;font-size:13px}#dsfig-u1-03 .t{fill:#16181D;font-weight:500}#dsfig-u1-03 .t.inv{fill:#FFFFFF;font-weight:700}#dsfig-u1-03 .kd{stroke:#16181D;stroke-width:1.2}#dsfig-u1-03 .dot{fill:#16181D}#dsfig-u1-03 .ann{fill:#2340B8;font-size:11px;font-weight:700}#dsfig-u1-03 .lbl{fill:#6F7787;font-family:system-ui,-apple-system,sans-serif;font-size:12px;font-weight:700}#dsfig-u1-03 .ptr{fill:#2340B8;font-size:12px;font-weight:700}#dsfig-u1-03 .ah{fill:#454C5A}#dsfig-u1-03 .ah.hi{fill:#2340B8}#dsfig-u1-03 .wl rect{fill:#FFFFFF;stroke:#DCE0E7}#dsfig-u1-03 .wl .t{font-size:12px;font-weight:700}#dsfig-u1-03 .wl.hi rect{fill:#2340B8;stroke:#2340B8}#dsfig-u1-03 .wl.hi .t{fill:#FFFFFF}html.dark #dsfig-u1-03 .e{stroke:#B1B7C3}html.dark #dsfig-u1-03 .e.hi{stroke:#8FA3FF}html.dark #dsfig-u1-03 .n{fill:#161920;stroke:#E6E8ED}html.dark #dsfig-u1-03 .n.hi{fill:#1E2748;stroke:#8FA3FF}html.dark #dsfig-u1-03 .n.rb-b{fill:#E6E8ED;stroke:#E6E8ED}html.dark #dsfig-u1-03 .n.rb-r{fill:#FF7E71;stroke:#FF7E71}html.dark #dsfig-u1-03 .t{fill:#E6E8ED}html.dark #dsfig-u1-03 .t.inv{fill:#0F1115}html.dark #dsfig-u1-03 .kd{stroke:#E6E8ED}html.dark #dsfig-u1-03 .dot{fill:#E6E8ED}html.dark #dsfig-u1-03 .ann{fill:#8FA3FF}html.dark #dsfig-u1-03 .lbl{fill:#858D9C}html.dark #dsfig-u1-03 .ptr{fill:#8FA3FF}html.dark #dsfig-u1-03 .ah{fill:#B1B7C3}html.dark #dsfig-u1-03 .ah.hi{fill:#8FA3FF}html.dark #dsfig-u1-03 .wl rect{fill:#161920;stroke:#2A2E37}html.dark #dsfig-u1-03 .wl.hi rect{fill:#8FA3FF;stroke:#8FA3FF}html.dark #dsfig-u1-03 .wl.hi .t{fill:#0F1115}</style><defs><marker id="ah3" 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="ahh3" 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="M57.8,46.6 Q126,72 192.3,47.3" marker-end="url(#ah3)"/><path class="e" d="M194.2,33.4 Q126,8 59.7,32.7" marker-end="url(#ah3)"/><path class="e" d="M360,40 L449,40" marker-end="url(#ah3)"/><path class="e" d="M489,40 L578,40" marker-end="url(#ah3)"/><g class="wl"><rect x="94.8" y="50.5" width="61.5" height="18" rx="9"/><text class="t" x="125.5" y="59.5" dy=".35em" text-anchor="middle">request</text></g><g class="wl"><rect x="92.1" y="11.5" width="68.7" height="18" rx="9"/><text class="t" x="126.5" y="20.5" dy=".35em" text-anchor="middle">response</text></g><g class="wl"><rect x="374.8" y="31" width="61.5" height="18" rx="9"/><text class="t" x="405.5" y="40" dy=".35em" text-anchor="middle">publish</text></g><g class="wl"><rect x="507.4" y="31" width="54.3" height="18" rx="9"/><text class="t" x="534.5" y="40" dy=".35em" text-anchor="middle">notify</text></g><circle class="n" cx="40" cy="40" r="18"/><text class="t" x="40" y="40" dy=".35em" text-anchor="middle">C</text><circle class="n" cx="212" cy="40" r="18"/><text class="t" x="212" y="40" dy=".35em" text-anchor="middle">S</text><circle class="n" cx="341" cy="40" r="18"/><text class="t" x="341" y="40" dy=".35em" text-anchor="middle">P</text><circle class="n" cx="470" cy="40" r="18"/><text class="t" x="470" y="40" dy=".35em" text-anchor="middle">B</text><circle class="n" cx="599" cy="40" r="18"/><text class="t" x="599" y="40" dy=".35em" text-anchor="middle">U</text></svg><figcaption style="font-size:.82em;opacity:.72;margin-top:.45rem">Left: request-response (C client, S server). Right: publish-subscribe (P publisher, B broker, U subscriber)</figcaption></figure>

<figure class="ds-fig" style="margin:1.4rem 0;overflow-x:auto"><svg xmlns="http://www.w3.org/2000/svg" id="dsfig-u1-04" viewBox="0 0 639 80" width="639" height="80" role="img" aria-label="Left: push-pull (Pr producer, Q queue, Co consumer). Right: exclusive pair, a persistent two-way link between A and B2"><style>#dsfig-u1-04 .e{stroke:#454C5A;stroke-width:1.4;fill:none}#dsfig-u1-04 .e.hi{stroke:#2340B8;stroke-width:2.6}#dsfig-u1-04 .n{fill:#FFFFFF;stroke:#16181D;stroke-width:1.4}#dsfig-u1-04 .n.hi{fill:#E3E9FC;stroke:#2340B8;stroke-width:2.2}#dsfig-u1-04 .n.rb-b{fill:#16181D;stroke:#16181D}#dsfig-u1-04 .n.rb-r{fill:#BD3227;stroke:#BD3227}#dsfig-u1-04 text{font-family:"JetBrains Mono",ui-monospace,Menlo,Consolas,monospace;font-size:13px}#dsfig-u1-04 .t{fill:#16181D;font-weight:500}#dsfig-u1-04 .t.inv{fill:#FFFFFF;font-weight:700}#dsfig-u1-04 .kd{stroke:#16181D;stroke-width:1.2}#dsfig-u1-04 .dot{fill:#16181D}#dsfig-u1-04 .ann{fill:#2340B8;font-size:11px;font-weight:700}#dsfig-u1-04 .lbl{fill:#6F7787;font-family:system-ui,-apple-system,sans-serif;font-size:12px;font-weight:700}#dsfig-u1-04 .ptr{fill:#2340B8;font-size:12px;font-weight:700}#dsfig-u1-04 .ah{fill:#454C5A}#dsfig-u1-04 .ah.hi{fill:#2340B8}#dsfig-u1-04 .wl rect{fill:#FFFFFF;stroke:#DCE0E7}#dsfig-u1-04 .wl .t{font-size:12px;font-weight:700}#dsfig-u1-04 .wl.hi rect{fill:#2340B8;stroke:#2340B8}#dsfig-u1-04 .wl.hi .t{fill:#FFFFFF}html.dark #dsfig-u1-04 .e{stroke:#B1B7C3}html.dark #dsfig-u1-04 .e.hi{stroke:#8FA3FF}html.dark #dsfig-u1-04 .n{fill:#161920;stroke:#E6E8ED}html.dark #dsfig-u1-04 .n.hi{fill:#1E2748;stroke:#8FA3FF}html.dark #dsfig-u1-04 .n.rb-b{fill:#E6E8ED;stroke:#E6E8ED}html.dark #dsfig-u1-04 .n.rb-r{fill:#FF7E71;stroke:#FF7E71}html.dark #dsfig-u1-04 .t{fill:#E6E8ED}html.dark #dsfig-u1-04 .t.inv{fill:#0F1115}html.dark #dsfig-u1-04 .kd{stroke:#E6E8ED}html.dark #dsfig-u1-04 .dot{fill:#E6E8ED}html.dark #dsfig-u1-04 .ann{fill:#8FA3FF}html.dark #dsfig-u1-04 .lbl{fill:#858D9C}html.dark #dsfig-u1-04 .ptr{fill:#8FA3FF}html.dark #dsfig-u1-04 .ah{fill:#B1B7C3}html.dark #dsfig-u1-04 .ah.hi{fill:#8FA3FF}html.dark #dsfig-u1-04 .wl rect{fill:#161920;stroke:#2A2E37}html.dark #dsfig-u1-04 .wl.hi rect{fill:#8FA3FF;stroke:#8FA3FF}html.dark #dsfig-u1-04 .wl.hi .t{fill:#0F1115}</style><defs><marker id="ah4" 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="ahh4" 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 L191,40" marker-end="url(#ah4)"/><path class="e" d="M365,40 L233,40" marker-end="url(#ah4)"/><path class="e" d="M491,40 L578,40" marker-end="url(#ah4)" marker-start="url(#ah4)"/><g class="wl"><rect x="105.6" y="31" width="40.8" height="18" rx="9"/><text class="t" x="126" y="40" dy=".35em" text-anchor="middle">push</text></g><g class="wl"><rect x="277.6" y="31" width="40.8" height="18" rx="9"/><text class="t" x="298" y="40" dy=".35em" text-anchor="middle">pull</text></g><g class="wl"><rect x="514.1" y="31" width="40.8" height="18" rx="9"/><text class="t" x="534.5" y="40" dy=".35em" text-anchor="middle">open</text></g><circle class="n" cx="40" cy="40" r="18"/><text class="t" x="40" y="40" dy=".35em" text-anchor="middle">Pr</text><circle class="n" cx="212" cy="40" r="18"/><text class="t" x="212" y="40" dy=".35em" text-anchor="middle">Q</text><circle class="n" cx="384" cy="40" r="18"/><text class="t" x="384" y="40" dy=".35em" text-anchor="middle">Co</text><circle class="n" cx="470" cy="40" r="18"/><text class="t" x="470" y="40" dy=".35em" text-anchor="middle">A</text><circle class="n" cx="599" cy="40" r="18"/><text class="t" x="599" y="40" dy=".35em" text-anchor="middle">B2</text></svg><figcaption style="font-size:.82em;opacity:.72;margin-top:.45rem">Left: push-pull (Pr producer, Q queue, Co consumer). Right: exclusive pair, a persistent two-way link between A and B2</figcaption></figure>

IoT levels. Levels 3 and 4 differ in where data is analysed and stored.

<figure class="ds-fig" style="margin:1.4rem 0;overflow-x:auto"><svg xmlns="http://www.w3.org/2000/svg" id="dsfig-u1-05" viewBox="0 0 596 80" width="596" height="80" role="img" aria-label="Level 3: one node sends data to the cloud, where it is stored, analysed and served to the app"><style>#dsfig-u1-05 .e{stroke:#454C5A;stroke-width:1.4;fill:none}#dsfig-u1-05 .e.hi{stroke:#2340B8;stroke-width:2.6}#dsfig-u1-05 .n{fill:#FFFFFF;stroke:#16181D;stroke-width:1.4}#dsfig-u1-05 .n.hi{fill:#E3E9FC;stroke:#2340B8;stroke-width:2.2}#dsfig-u1-05 .n.rb-b{fill:#16181D;stroke:#16181D}#dsfig-u1-05 .n.rb-r{fill:#BD3227;stroke:#BD3227}#dsfig-u1-05 text{font-family:"JetBrains Mono",ui-monospace,Menlo,Consolas,monospace;font-size:13px}#dsfig-u1-05 .t{fill:#16181D;font-weight:500}#dsfig-u1-05 .t.inv{fill:#FFFFFF;font-weight:700}#dsfig-u1-05 .kd{stroke:#16181D;stroke-width:1.2}#dsfig-u1-05 .dot{fill:#16181D}#dsfig-u1-05 .ann{fill:#2340B8;font-size:11px;font-weight:700}#dsfig-u1-05 .lbl{fill:#6F7787;font-family:system-ui,-apple-system,sans-serif;font-size:12px;font-weight:700}#dsfig-u1-05 .ptr{fill:#2340B8;font-size:12px;font-weight:700}#dsfig-u1-05 .ah{fill:#454C5A}#dsfig-u1-05 .ah.hi{fill:#2340B8}#dsfig-u1-05 .wl rect{fill:#FFFFFF;stroke:#DCE0E7}#dsfig-u1-05 .wl .t{font-size:12px;font-weight:700}#dsfig-u1-05 .wl.hi rect{fill:#2340B8;stroke:#2340B8}#dsfig-u1-05 .wl.hi .t{fill:#FFFFFF}html.dark #dsfig-u1-05 .e{stroke:#B1B7C3}html.dark #dsfig-u1-05 .e.hi{stroke:#8FA3FF}html.dark #dsfig-u1-05 .n{fill:#161920;stroke:#E6E8ED}html.dark #dsfig-u1-05 .n.hi{fill:#1E2748;stroke:#8FA3FF}html.dark #dsfig-u1-05 .n.rb-b{fill:#E6E8ED;stroke:#E6E8ED}html.dark #dsfig-u1-05 .n.rb-r{fill:#FF7E71;stroke:#FF7E71}html.dark #dsfig-u1-05 .t{fill:#E6E8ED}html.dark #dsfig-u1-05 .t.inv{fill:#0F1115}html.dark #dsfig-u1-05 .kd{stroke:#E6E8ED}html.dark #dsfig-u1-05 .dot{fill:#E6E8ED}html.dark #dsfig-u1-05 .ann{fill:#8FA3FF}html.dark #dsfig-u1-05 .lbl{fill:#858D9C}html.dark #dsfig-u1-05 .ptr{fill:#8FA3FF}html.dark #dsfig-u1-05 .ah{fill:#B1B7C3}html.dark #dsfig-u1-05 .ah.hi{fill:#8FA3FF}html.dark #dsfig-u1-05 .wl rect{fill:#161920;stroke:#2A2E37}html.dark #dsfig-u1-05 .wl.hi rect{fill:#8FA3FF;stroke:#8FA3FF}html.dark #dsfig-u1-05 .wl.hi .t{fill:#0F1115}</style><defs><marker id="ah5" 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="ahh5" 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 L191,40" marker-end="url(#ah5)"/><path class="e" d="M231,40 L363,40" marker-end="url(#ah5)"/><path class="e" d="M231,40 L535,40" marker-end="url(#ah5)"/><g class="wl"><rect x="105.6" y="31" width="40.8" height="18" rx="9"/><text class="t" x="126" y="40" dy=".35em" text-anchor="middle">data</text></g><circle class="n" cx="40" cy="40" r="18"/><text class="t" x="40" y="40" dy=".35em" text-anchor="middle">N</text><circle class="n" cx="212" cy="40" r="18"/><text class="t" x="212" y="40" dy=".35em" text-anchor="middle">Cl</text><circle class="n" cx="384" cy="40" r="18"/><text class="t" x="384" y="40" dy=".35em" text-anchor="middle">An</text><circle class="n" cx="556" cy="40" r="18"/><text class="t" x="556" y="40" dy=".35em" text-anchor="middle">Ap</text></svg><figcaption style="font-size:.82em;opacity:.72;margin-top:.45rem">Level 3: one node sends data to the cloud, where it is stored, analysed and served to the app</figcaption></figure>

<figure class="ds-fig" style="margin:1.4rem 0;overflow-x:auto"><svg xmlns="http://www.w3.org/2000/svg" id="dsfig-u1-06" viewBox="0 0 510 252" width="510" height="252" role="img" aria-label="Level 4: many nodes analyse locally and store in the cloud; observer nodes and the app read the data"><style>#dsfig-u1-06 .e{stroke:#454C5A;stroke-width:1.4;fill:none}#dsfig-u1-06 .e.hi{stroke:#2340B8;stroke-width:2.6}#dsfig-u1-06 .n{fill:#FFFFFF;stroke:#16181D;stroke-width:1.4}#dsfig-u1-06 .n.hi{fill:#E3E9FC;stroke:#2340B8;stroke-width:2.2}#dsfig-u1-06 .n.rb-b{fill:#16181D;stroke:#16181D}#dsfig-u1-06 .n.rb-r{fill:#BD3227;stroke:#BD3227}#dsfig-u1-06 text{font-family:"JetBrains Mono",ui-monospace,Menlo,Consolas,monospace;font-size:13px}#dsfig-u1-06 .t{fill:#16181D;font-weight:500}#dsfig-u1-06 .t.inv{fill:#FFFFFF;font-weight:700}#dsfig-u1-06 .kd{stroke:#16181D;stroke-width:1.2}#dsfig-u1-06 .dot{fill:#16181D}#dsfig-u1-06 .ann{fill:#2340B8;font-size:11px;font-weight:700}#dsfig-u1-06 .lbl{fill:#6F7787;font-family:system-ui,-apple-system,sans-serif;font-size:12px;font-weight:700}#dsfig-u1-06 .ptr{fill:#2340B8;font-size:12px;font-weight:700}#dsfig-u1-06 .ah{fill:#454C5A}#dsfig-u1-06 .ah.hi{fill:#2340B8}#dsfig-u1-06 .wl rect{fill:#FFFFFF;stroke:#DCE0E7}#dsfig-u1-06 .wl .t{font-size:12px;font-weight:700}#dsfig-u1-06 .wl.hi rect{fill:#2340B8;stroke:#2340B8}#dsfig-u1-06 .wl.hi .t{fill:#FFFFFF}html.dark #dsfig-u1-06 .e{stroke:#B1B7C3}html.dark #dsfig-u1-06 .e.hi{stroke:#8FA3FF}html.dark #dsfig-u1-06 .n{fill:#161920;stroke:#E6E8ED}html.dark #dsfig-u1-06 .n.hi{fill:#1E2748;stroke:#8FA3FF}html.dark #dsfig-u1-06 .n.rb-b{fill:#E6E8ED;stroke:#E6E8ED}html.dark #dsfig-u1-06 .n.rb-r{fill:#FF7E71;stroke:#FF7E71}html.dark #dsfig-u1-06 .t{fill:#E6E8ED}html.dark #dsfig-u1-06 .t.inv{fill:#0F1115}html.dark #dsfig-u1-06 .kd{stroke:#E6E8ED}html.dark #dsfig-u1-06 .dot{fill:#E6E8ED}html.dark #dsfig-u1-06 .ann{fill:#8FA3FF}html.dark #dsfig-u1-06 .lbl{fill:#858D9C}html.dark #dsfig-u1-06 .ptr{fill:#8FA3FF}html.dark #dsfig-u1-06 .ah{fill:#B1B7C3}html.dark #dsfig-u1-06 .ah.hi{fill:#8FA3FF}html.dark #dsfig-u1-06 .wl rect{fill:#161920;stroke:#2A2E37}html.dark #dsfig-u1-06 .wl.hi rect{fill:#8FA3FF;stroke:#8FA3FF}html.dark #dsfig-u1-06 .wl.hi .t{fill:#0F1115}</style><defs><marker id="ah6" 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="ahh6" 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="M58,46 L278.1,119.4" marker-end="url(#ah6)"/><path class="e" d="M59,126 L277,126" marker-end="url(#ah6)"/><path class="e" d="M58,206 L278.1,132.6" marker-end="url(#ah6)"/><path class="e" d="M315,117.5 L451.2,49.4" marker-end="url(#ah6)"/><path class="e" d="M315,134.5 L451.2,202.6" marker-end="url(#ah6)"/><circle class="n" cx="40" cy="40" r="18"/><text class="t" x="40" y="40" dy=".35em" text-anchor="middle">N1</text><circle class="n" cx="40" cy="126" r="18"/><text class="t" x="40" y="126" dy=".35em" text-anchor="middle">N2</text><circle class="n" cx="40" cy="212" r="18"/><text class="t" x="40" y="212" dy=".35em" text-anchor="middle">N3</text><circle class="n" cx="298" cy="126" r="18"/><text class="t" x="298" y="126" dy=".35em" text-anchor="middle">Cl</text><circle class="n" cx="470" cy="40" r="18"/><text class="t" x="470" y="40" dy=".35em" text-anchor="middle">Ob</text><circle class="n" cx="470" cy="212" r="18"/><text class="t" x="470" y="212" dy=".35em" text-anchor="middle">Ap</text></svg><figcaption style="font-size:.82em;opacity:.72;margin-top:.45rem">Level 4: many nodes analyse locally and store in the cloud; observer nodes and the app read the data</figcaption></figure>

Point Level 3 Level 4
Nodes Single node Multiple nodes
Analysis In the cloud (data is big, computation heavy) Locally on the nodes, cloud used for storage
Storage Cloud Cloud
Extra Cloud application Observer nodes that only read and process data
Example Tracking package handling with a single node and cloud analytics Noise monitoring of a city with many nodes

Key points.

  1. Logical design has six functional blocks: device, communication, services, management, security and application.
  2. Level 3 suits a single node with heavy analysis in the cloud, while Level 4 suits many nodes and big data where local analysis saves bandwidth.
  3. Level 4 nodes analyse first, which cuts latency and traffic.

Answer frame. For the differentiate question: open with the two definitions, give the 6-row table, then close with the smart-home example. For levels: open with what a level means, draw both figures, contrast on nodes, analysis and storage, and finish with the two examples. For communication models: name all four, draw one small figure for each, give protocol examples, and close with when each is used.

Asked: [7 marks] (May 2022, Dec 2024) Draw and explain IoT level 3 and level 4 system. Give suitable examples for them. / How IoT level 3 and level 4 system differ from each other? Explain. Asked: [7 marks] (May 2022) What are various IoT Communication models? Draw and explain them in brief. Asked: [7 marks] (Jun 2025) Differentiate between Logical and Physical design of IoT. Pitfall: Do not swap the levels; Level 3 has one node and cloud analysis, Level 4 has many nodes and local analysis.

IoT enablers

<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>Enablers are the technologies that make IoT possible: sensors, networks, cloud computing, analytics and security, arranged in planes that depend on each other.</mark>

Key points.

  1. The device plane (sensors, actuators, embedded boards) produces and consumes data.
  2. The network plane (wireless links, gateways, protocols) carries the data.
  3. The cloud and data plane stores it and runs analytics and machine learning on it.
  4. The application plane turns the results into services.
  5. Security and management cut across all planes, and no plane works alone: sensors need networks, networks need cloud, cloud analytics need clean sensor data.

<figure class="ds-fig" style="margin:1.4rem 0;overflow-x:auto"><svg xmlns="http://www.w3.org/2000/svg" id="dsfig-u1-07" viewBox="0 0 596 252" width="596" height="252" role="img" aria-label="Enablers: sensors, networks, cloud, analytics, application; security (Sec) supports all"><style>#dsfig-u1-07 .e{stroke:#454C5A;stroke-width:1.4;fill:none}#dsfig-u1-07 .e.hi{stroke:#2340B8;stroke-width:2.6}#dsfig-u1-07 .n{fill:#FFFFFF;stroke:#16181D;stroke-width:1.4}#dsfig-u1-07 .n.hi{fill:#E3E9FC;stroke:#2340B8;stroke-width:2.2}#dsfig-u1-07 .n.rb-b{fill:#16181D;stroke:#16181D}#dsfig-u1-07 .n.rb-r{fill:#BD3227;stroke:#BD3227}#dsfig-u1-07 text{font-family:"JetBrains Mono",ui-monospace,Menlo,Consolas,monospace;font-size:13px}#dsfig-u1-07 .t{fill:#16181D;font-weight:500}#dsfig-u1-07 .t.inv{fill:#FFFFFF;font-weight:700}#dsfig-u1-07 .kd{stroke:#16181D;stroke-width:1.2}#dsfig-u1-07 .dot{fill:#16181D}#dsfig-u1-07 .ann{fill:#2340B8;font-size:11px;font-weight:700}#dsfig-u1-07 .lbl{fill:#6F7787;font-family:system-ui,-apple-system,sans-serif;font-size:12px;font-weight:700}#dsfig-u1-07 .ptr{fill:#2340B8;font-size:12px;font-weight:700}#dsfig-u1-07 .ah{fill:#454C5A}#dsfig-u1-07 .ah.hi{fill:#2340B8}#dsfig-u1-07 .wl rect{fill:#FFFFFF;stroke:#DCE0E7}#dsfig-u1-07 .wl .t{font-size:12px;font-weight:700}#dsfig-u1-07 .wl.hi rect{fill:#2340B8;stroke:#2340B8}#dsfig-u1-07 .wl.hi .t{fill:#FFFFFF}html.dark #dsfig-u1-07 .e{stroke:#B1B7C3}html.dark #dsfig-u1-07 .e.hi{stroke:#8FA3FF}html.dark #dsfig-u1-07 .n{fill:#161920;stroke:#E6E8ED}html.dark #dsfig-u1-07 .n.hi{fill:#1E2748;stroke:#8FA3FF}html.dark #dsfig-u1-07 .n.rb-b{fill:#E6E8ED;stroke:#E6E8ED}html.dark #dsfig-u1-07 .n.rb-r{fill:#FF7E71;stroke:#FF7E71}html.dark #dsfig-u1-07 .t{fill:#E6E8ED}html.dark #dsfig-u1-07 .t.inv{fill:#0F1115}html.dark #dsfig-u1-07 .kd{stroke:#E6E8ED}html.dark #dsfig-u1-07 .dot{fill:#E6E8ED}html.dark #dsfig-u1-07 .ann{fill:#8FA3FF}html.dark #dsfig-u1-07 .lbl{fill:#858D9C}html.dark #dsfig-u1-07 .ptr{fill:#8FA3FF}html.dark #dsfig-u1-07 .ah{fill:#B1B7C3}html.dark #dsfig-u1-07 .ah.hi{fill:#8FA3FF}html.dark #dsfig-u1-07 .wl rect{fill:#161920;stroke:#2A2E37}html.dark #dsfig-u1-07 .wl.hi rect{fill:#8FA3FF;stroke:#8FA3FF}html.dark #dsfig-u1-07 .wl.hi .t{fill:#0F1115}</style><defs><marker id="ah7" 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="ahh7" 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(#ah7)"/><path class="e" d="M188,40 L277,40" marker-end="url(#ah7)"/><path class="e" d="M317,40 L406,40" marker-end="url(#ah7)"/><path class="e" d="M446,40 L535,40" marker-end="url(#ah7)"/><path class="e hi" d="M298,193 L298,59"/><path class="e" d="M286.6,196.8 L180.4,55.2"/><path class="e" d="M282.2,201.5 L55.8,50.5"/><circle class="n" cx="40" cy="40" r="18"/><text class="t" x="40" y="40" dy=".35em" text-anchor="middle">Sen</text><circle class="n" cx="169" cy="40" r="18"/><text class="t" x="169" y="40" dy=".35em" text-anchor="middle">Net</text><circle class="n" cx="298" cy="40" r="18"/><text class="t" x="298" y="40" dy=".35em" text-anchor="middle">Cld</text><circle class="n" cx="427" cy="40" r="18"/><text class="t" x="427" y="40" dy=".35em" text-anchor="middle">Ana</text><circle class="n" cx="556" cy="40" r="18"/><text class="t" x="556" y="40" dy=".35em" text-anchor="middle">App</text><circle class="n" cx="298" cy="212" r="18"/><text class="t" x="298" y="212" dy=".35em" text-anchor="middle">Sec</text></svg><figcaption style="font-size:.82em;opacity:.72;margin-top:.45rem">Enablers: sensors, networks, cloud, analytics, application; security (Sec) supports all</figcaption></figure>

Asked: [7 marks] (May 2024) Explain the IoT planes, various enablers of IoT, and the complex interdependencies among them with a block diagram.

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">Low weight</span>

Definition. <mark>Modern IoT applications use connected sensors and analytics to monitor and automate processes in homes, health, cities, farms and factories.</mark>

Key points.

  1. Healthcare: wearables and connected monitors track heart rate and glucose and alert doctors remotely.
  2. Smart city: sensors manage street lighting, traffic, parking, waste bins and air quality.
  3. Agriculture: soil-moisture and weather sensors drive automatic irrigation and reduce water use.
  4. Industrial automation (IIoT): machine sensors enable predictive maintenance and cut downtime.
  5. The common benefits are efficiency, real-time monitoring and automation.

Asked: [7 marks] (May 2026) Describe modern day IoT applications in healthcare, smart city, agriculture and industrial automation systems with suitable examples.

M2M communications

<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>Machine-to-Machine communication is the direct exchange of data between devices over wired or wireless networks without human intervention.</mark>

Key points.

  1. M2M links are usually point to point over dedicated or cellular networks, for example an ATM talking to a bank server.
  2. The M2M service layer is a common software layer that gives applications standard access to devices.
  3. ETSI M2M defines this layer with three domains: device, network and applications.
  4. The device domain holds M2M devices and gateways; the network domain holds the core network and the service capabilities layer; the application domain holds the M2M applications.
  5. Standard interfaces and resources (in the oneM2M work as well) let devices from different vendors interoperate and cut development cost.

Asked: [7 marks] (May 2023) Explain M2M service layer standardization.

IoT vs M2M

<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>M2M is direct machine communication over dedicated networks, while IoT is a wider network of things connected through the Internet and cloud with analytics on top.</mark>

Comparison.

Basis M2M IoT
Communication Point to point, often cellular or wired Over the Internet, using IP
Scope Small, closed, one application Large, open, many applications
Devices Homogeneous, same vendor Heterogeneous, many vendors
Data analytics Local or centralised, limited Cloud and big-data analytics
Example ATM, vending machine Smart home, smart city

Key points.

  1. In M2M the data goes to a single server for one purpose, but in IoT it is stored in the cloud and mined by analytics for many purposes.
  2. The shift from M2M to IoT came because point-to-point links could not give broad connectivity.
  3. It also came from the need to integrate cloud services and to deploy at massive scale.

Answer frame. Open with the two definitions; give the 7-row table; add a short line on analytics (centralised in M2M, cloud in IoT); for the shift question, list points 2-4; close with one example each.

Asked: [7 marks] (May 2022, May 2026) Explain M2M communication and bring out differences between IoT and M2M. How data analytics approaches different in M2M and IoT. / Analyze IoT vs M2M and IoT vs Web of Things (WoT) with suitable examples and applications. Asked: [? marks] (Dec 2024) Define M2M. Explain reasons of shifting from M2M to IoT.

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">Not asked since 2022</span>

Definition. <mark>The Web of Things reuses web standards (HTTP, REST, URLs, JSON) to make physical objects part of the World Wide Web, so it is an application layer on top of IoT.</mark>

Key points.

  1. IoT is about connecting devices with any protocol, while WoT is about how their data is accessed through the web.
  2. In WoT every thing is a web resource with a URL, which gives easy interoperability.
  3. Example: a smart bulb controlled from a web page over HTTP is WoT.

IoT reference architecture

<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>An IoT reference architecture is a common blueprint of layers and functions that guides how IoT systems are designed, with an information model describing the entities they handle.</mark>

Diagram. <figure class="ds-fig" style="margin:1.4rem 0;overflow-x:auto"><svg xmlns="http://www.w3.org/2000/svg" id="dsfig-u1-08" viewBox="0 0 467 252" width="467" height="252" role="img" aria-label="Reference architecture: Dev device, Com communication, Ser services, App application, Man management, Sec security layers"><style>#dsfig-u1-08 .e{stroke:#454C5A;stroke-width:1.4;fill:none}#dsfig-u1-08 .e.hi{stroke:#2340B8;stroke-width:2.6}#dsfig-u1-08 .n{fill:#FFFFFF;stroke:#16181D;stroke-width:1.4}#dsfig-u1-08 .n.hi{fill:#E3E9FC;stroke:#2340B8;stroke-width:2.2}#dsfig-u1-08 .n.rb-b{fill:#16181D;stroke:#16181D}#dsfig-u1-08 .n.rb-r{fill:#BD3227;stroke:#BD3227}#dsfig-u1-08 text{font-family:"JetBrains Mono",ui-monospace,Menlo,Consolas,monospace;font-size:13px}#dsfig-u1-08 .t{fill:#16181D;font-weight:500}#dsfig-u1-08 .t.inv{fill:#FFFFFF;font-weight:700}#dsfig-u1-08 .kd{stroke:#16181D;stroke-width:1.2}#dsfig-u1-08 .dot{fill:#16181D}#dsfig-u1-08 .ann{fill:#2340B8;font-size:11px;font-weight:700}#dsfig-u1-08 .lbl{fill:#6F7787;font-family:system-ui,-apple-system,sans-serif;font-size:12px;font-weight:700}#dsfig-u1-08 .ptr{fill:#2340B8;font-size:12px;font-weight:700}#dsfig-u1-08 .ah{fill:#454C5A}#dsfig-u1-08 .ah.hi{fill:#2340B8}#dsfig-u1-08 .wl rect{fill:#FFFFFF;stroke:#DCE0E7}#dsfig-u1-08 .wl .t{font-size:12px;font-weight:700}#dsfig-u1-08 .wl.hi rect{fill:#2340B8;stroke:#2340B8}#dsfig-u1-08 .wl.hi .t{fill:#FFFFFF}html.dark #dsfig-u1-08 .e{stroke:#B1B7C3}html.dark #dsfig-u1-08 .e.hi{stroke:#8FA3FF}html.dark #dsfig-u1-08 .n{fill:#161920;stroke:#E6E8ED}html.dark #dsfig-u1-08 .n.hi{fill:#1E2748;stroke:#8FA3FF}html.dark #dsfig-u1-08 .n.rb-b{fill:#E6E8ED;stroke:#E6E8ED}html.dark #dsfig-u1-08 .n.rb-r{fill:#FF7E71;stroke:#FF7E71}html.dark #dsfig-u1-08 .t{fill:#E6E8ED}html.dark #dsfig-u1-08 .t.inv{fill:#0F1115}html.dark #dsfig-u1-08 .kd{stroke:#E6E8ED}html.dark #dsfig-u1-08 .dot{fill:#E6E8ED}html.dark #dsfig-u1-08 .ann{fill:#8FA3FF}html.dark #dsfig-u1-08 .lbl{fill:#858D9C}html.dark #dsfig-u1-08 .ptr{fill:#8FA3FF}html.dark #dsfig-u1-08 .ah{fill:#B1B7C3}html.dark #dsfig-u1-08 .ah.hi{fill:#8FA3FF}html.dark #dsfig-u1-08 .wl rect{fill:#161920;stroke:#2A2E37}html.dark #dsfig-u1-08 .wl.hi rect{fill:#8FA3FF;stroke:#8FA3FF}html.dark #dsfig-u1-08 .wl.hi .t{fill:#0F1115}</style><defs><marker id="ah8" 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="ahh8" 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(#ah8)"/><path class="e" d="M188,40 L277,40" marker-end="url(#ah8)"/><path class="e" d="M317,40 L406,40" marker-end="url(#ah8)"/><path class="e" d="M207.4,193.6 L173.6,58.4"/><path class="e" d="M220.5,195 L289.5,57"/><path class="e" d="M375.5,195 L306.5,57"/><path class="e" d="M388.6,193.6 L422.4,58.4"/><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">Ser</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="212" cy="212" r="18"/><text class="t" x="212" y="212" dy=".35em" text-anchor="middle">Man</text><circle class="n" cx="384" cy="212" r="18"/><text class="t" x="384" y="212" dy=".35em" text-anchor="middle">Sec</text></svg><figcaption style="font-size:.82em;opacity:.72;margin-top:.45rem">Reference architecture: Dev device, Com communication, Ser services, App application, Man management, Sec security layers</figcaption></figure>

Key points.

  1. The functional view has device, communication, services, application, management and security layers.
  2. The information model describes the entities and their attributes, and how they relate.
  3. It separates physical entities (a room, a person) from virtual entities (their digital representation).
  4. A domain model links the physical entity to the devices that sense it and the services that expose it.
  5. The functional view says what the system does and the information view says what data it holds; both together describe the system.

Asked: [7 marks] (May 2022) Describe IoT reference architecture and information model.

IoT Network configurations

<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>A network configuration is the arrangement of nodes and links; the physical topology gives the layout and the connection type says whether a link joins two or many devices.</mark>

Key points.

  1. Star: every node connects to a central hub, so it is easy to manage but the hub is a single point of failure (used in home WiFi and ZigBee).
  2. Bus: nodes share a single backbone cable, which is cheap but a break stops the network.
  3. Ring: each node connects to two neighbours in a loop, so data passes around the ring.
  4. Mesh: nodes link to several others, which gives reliability and self-healing (used in ZigBee and wireless sensor networks).
  5. Tree: hierarchical star groups, suited to larger clusters of sensors.
  6. Point-to-point links join exactly two devices; multipoint links share one link among many.

Asked: [7 marks] (May 2024) Classify network types based on physical topologies and connection types with schematic diagrams.

IoT LAN

<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>An IoT LAN is a local network, such as WiFi, Ethernet, Bluetooth or ZigBee, that connects nodes in a home, building or campus.</mark>

Key points.

  1. Interoperability is a problem because devices and protocols from different vendors do not always work together.
  2. Limited bandwidth and battery power restrict how much data devices can send.
  3. Security and privacy risk is high because many cheap devices are weakly protected.
  4. Scalability, management, cost and limited device resources also constrain implementation.

Asked: [? marks] (Dec 2024) What issues might affect the development and Implementation of the 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>An IoT WAN is a wide-area network that carries IoT data over long distances, such as cellular, satellite or low-power wide-area (LPWAN) links.</mark>

Key points.

  1. It connects gateways or nodes to the cloud across cities or countries.
  2. Cellular (3G/4G/5G, NB-IoT) gives wide coverage; LoRaWAN and Sigfox give low power over long range.

IoT Node

<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>An IoT node is a device with a sensor or actuator, a small processor and a communication interface that senses or acts and sends data onward.</mark>

Key points.

  1. Its functions are sensing, simple processing and transmitting data.
  2. A node may connect directly to the network or through a gateway.
  3. Significance: nodes are the source of all IoT data, so the system scales by adding nodes.

Answer frame. For the joint question, define node, gateway and proxy in one line each, then describe the flow: node, gateway, proxy, cloud, and close with scalability and interoperability.

Asked: [7 marks] (May 2026) Explain IoT node, IoT gateway and IoT proxy and discuss their significance in IoT communication systems.

IoT Gateway

<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>An IoT gateway is a device that connects IoT nodes to the cloud, translating protocols and aggregating data between the local network and the Internet.</mark>

Key points.

  1. Protocol translation converts device protocols (ZigBee, BLE) into Internet protocols (MQTT, HTTP).
  2. Aggregation and filtering combine and reduce data before it goes to the cloud, saving bandwidth.
  3. Security functions such as encryption and authentication protect the link.
  4. The ecosystem works as a flow: devices sense, the gateway collects and translates, the cloud stores, analytics finds insight, and applications act on it.

Answer frame. Open with the gateway definition and need; list points 1-4; describe the ecosystem flow with a five-box figure (as in Components of IoT ecosystems); close with the benefit of scalability.

Asked: [7 marks] (Jun 2025) What is the functionality of IoT gateways? How does the IoT ecosystem work?

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 proxy is an intermediary between constrained nodes and clients that caches responses, translates protocols (for example HTTP to CoAP) and enforces security.</mark>

Key points.

  1. It caches responses so that constrained nodes do not answer every request, which saves their energy.
  2. It translates between web protocols and lightweight IoT protocols.

Review of Basic Microcontrollers

<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">High weight</span>

Definition. <mark>A microcontroller is a single-chip computer that contains a processor, memory and input-output peripherals, used to sense, control and communicate in embedded and IoT devices.</mark>

Key points.

  1. A microcontroller integrates CPU, flash (program) memory, SRAM (data), EEPROM and peripherals on one chip, which makes it cheap, small and low power.
  2. Common families are 8051, PIC, AVR (ATmega328P in Arduino Uno) and ARM Cortex-M; WiFi-enabled chips such as ESP8266 and ESP32 are popular for IoT.
  3. The ATmega328P has a 16 MHz clock, 32 KB flash, 2 KB SRAM, 1 KB EEPROM, 14 digital pins and 6 analog inputs.
  4. It differs from a microprocessor, which needs external memory and I/O chips.
  5. In IoT the microcontroller is the brain of the node: it reads sensors, runs the code, and sends data through a radio module.

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Answer frame. Open with the definition; draw the block diagram; develop points 1-3 (structure, families, example chip), then 4-5 (IoT role), and end with interfacing and one application. For the CoAP part, see Unit 4.

Asked: [14 marks] (May 2024) Write short notes on two of the following: i) Review of basic microcontrollers and interfacing ii) Quantization error iii) ZigBee and its types iv) XMPP Asked: [7 marks] (Jun 2025) Explain the following: i) Review of Basic Microcontrollers and interfacing ii) CoAP Request-Response model Pitfall: Interfacing is part of the answer here; always add a line on how sensors connect to the chip.

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>Interfacing is connecting sensors, actuators and communication modules to a microcontroller through its pins and serial buses.</mark>

Key points.

  1. GPIO pins read digital inputs such as switches and drive outputs such as LEDs and relays.
  2. The ADC converts analog sensor voltage to digital numbers; PWM gives analog-like output to control a motor or dimmer.
  3. Serial buses connect chips: UART (2 wires, asynchronous), I2C (2 wires, addressed, many devices) and SPI (4 wires, fast).

Last-minute revision

  • IoT: physical things with sensors, software and connectivity exchanging data over the Internet.
  • Four layers: perception, network, middleware, application.
  • Ecosystem: devices, connectivity, platform, analytics, applications.
  • Physical design is hardware and protocols; logical design is functional blocks and communication models.
  • Communication models: request-response, publish-subscribe, push-pull, exclusive pair.
  • Level 3: single node, analysis and storage in the cloud; Level 4: many nodes, local analysis, cloud storage, observer nodes.
  • ETSI M2M has device, network and application domains.
  • M2M: point to point, closed, homogeneous; IoT: Internet, open, heterogeneous, cloud analytics.
  • WoT is the application layer that uses web standards on top of IoT.
  • Reference architecture: functional view plus information model of physical and virtual entities.
  • Gateway: protocol translation, aggregation, filtering, security.
  • Microcontroller: CPU, memory and peripherals on one chip; ATmega328P has 32 KB flash and 2 KB SRAM.

Memory hooks

  • PNMA: Perception, Network, Middleware, Application from the bottom up.
  • Four models: "RP-PE": Request-response, Publish-subscribe, Push-pull, Exclusive pair.
  • Level 3 = one node to cloud; Level 4 = many nodes plus local analysis.
  • M2M is a private phone line, IoT is the open Internet.
  • Interfacing buses: UART 2 wires, I2C 2 wires, SPI 4 wires.

Coverage checklist

  • IoT definition: definition and key points.
  • Characteristics: six characteristics.
  • IoT conceptual and architectural framework: Dec 2024 and May 2026 framework question.
  • Components of IoT ecosystems: May 2023 ecosystem question.
  • Physical and logical design of IoT: communication models (May 2022), levels 3 and 4 (May 2022, Dec 2024), logical vs physical (Jun 2025).
  • IoT enablers: May 2024 planes and enablers question.
  • Modern day IoT applications: May 2026 applications question.
  • M2M communications: May 2023 service layer question.
  • IoT vs M2M: May 2022, May 2026 comparison; Dec 2024 shift from M2M.
  • IoT vs WoT: covered, with the May 2026 comparison listed under IoT vs M2M.
  • IoT reference architecture: May 2022 question.
  • IoT Network configurations: May 2024 topologies question.
  • IoT LAN: Dec 2024 issues question.
  • IoT WAN: definition and key points.
  • IoT Node: May 2026 node, gateway and proxy question.
  • IoT Gateway: Jun 2025 gateway question.
  • IoT Proxy: definition and key points.
  • Review of Basic Microcontrollers: May 2024 and Jun 2025 questions.
  • interfacing: definition and key points.
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