The Internet of Things (IoT) stack

What the IoT is

The Internet of Things is the network of physical objects with embedded sensors, processors and connectivity that collect and exchange data over the internet, often without human input.

The four layers of the IoT stack

Data flows up from devices to applications; commands flow back down to actuators.

Benefits and drawbacks

Benefits: real-time monitoring and automation; data-driven decisions; remote control; efficiency (energy, water, maintenance before failure).

Drawbacks and risks: security (cheap devices with default passwords or no updates can be hijacked, for example into botnets); privacy (devices collect personal data); dependence on connectivity and the cloud provider; interoperability between brands; huge volumes of data to store and process.

Completing a diagram

An IoT diagram usually flows: devices (sensors/actuators) -> gateway -> network -> cloud platform (ingest, store, analyse, API) -> applications (dashboard, app), with commands flowing back down to actuators. Label each arrow with a connectivity method if asked.

Worked example

A smart home heating system has a room sensor, a boiler switch, a cloud service and a phone app. Map each to the IoT stack.

1. Room sensor and boiler switch: device hardware with firmware (device layer).
2. Home Wi-Fi and the internet link: connectivity layer.
3. Cloud service storing temperatures and running schedules, with an API: cloud platform.
4. Phone app the user sees: cloud application.

Answer: Device, connectivity, cloud platform, cloud application.

Check yourself

1. Which IoT layer contains data analytics and APIs?
   • Device hardware
   • Cloud platform
   • Connectivity
   • Sensor
   Show answer

   Cloud platform. The cloud platform collects, stores and analyses data and offers APIs.

2. Which belongs to the connectivity layer of an IoT stack?
   • A temperature sensor
   • A user dashboard
   • Data analytics
   • LoRaWAN and MQTT
   Show answer

   LoRaWAN and MQTT. Networks and protocols carry device data to the cloud.

3. A user views graphs of their energy use on a phone. Which IoT layer is this?
   • Device software
   • Cloud application
   • Connectivity
   • Gateway hardware
   Show answer

   Cloud application. End-user software is the application layer.

4. What does an API in an IoT cloud platform allow?
   • Sensors to measure temperature
   • Devices to charge their batteries
   • Other software to request data from or send commands to the platform in a standard way
   • Data to travel without a network
   Show answer

   Other software to request data from or send commands to the platform in a standard way. APIs let apps and services integrate with the platform.

5. Why are many IoT devices a security risk?
   • Cheap devices may ship with default passwords and rarely receive updates
   • They cannot connect to the internet
   • They use too much processing power
   • They store no data
   Show answer

   Cheap devices may ship with default passwords and rarely receive updates. Weak devices can be taken over, for example into botnets.

6. What is the role of a gateway in an IoT system?
   • It analyses all data using deep learning
   • It replaces the cloud platform
   • It links local low-power device networks to the internet and the cloud
   • It is a type of sensor
   Show answer

   It links local low-power device networks to the internet and the cloud. Gateways bridge short-range protocols to wider networks.

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Sources

• Pearson Edexcel International Advanced Subsidiary and Advanced Level in Computer Science specification (2026), Issue 1
• Pearson Edexcel IAL Computer Science sample assessment materials (Unit 3 paper, resource booklet and mark scheme)

Last updated 8 November 2026. Spotted a mistake? Tell us.