What are the different key layers of IoT architecture? part 1

A layered Internet of Things (IoT) architecture provides modularity, scalability, and flexibility, allowing each layer to focus on specific tasks and technologies. This FAQ series covers the five-layer IoT architecture and explains why it is a commonly used framework. This first part focuses on the first two layers.

IoT Architecture provides a structured framework for organizing interconnected components such as devices, sensors, networks, cloud services, and applications in an IoT ecosystem. It transforms basic connectivity into complex data-driven applications capable of monitoring, analysis, and control.

How has IoT architecture evolved to meet modern needs?

As IoT deployments became more complex, businesses needed better tools for complicated data processing. They also needed to ensure networks worked reliably in various settings and connect IoT systems to their regular operations.

IoT Architecture has progressed from simple three-layer models, i.e., perception, network, and application layer, to the now-standard five-layer framework. This evolution reflects IoT’s transition from technological novelty to business infrastructure. Figure 1 shows the different layers of this architecture and illustrates where each layer finds its purpose.

Figure 1. The five-layer IoT architecture to meet modern needs. (Image: Research Square)

The expanded five-layer model provides a comprehensive framework to address these evolving requirements, as follows:

The perception layer captures physical data through sensors and actuators.
The network layer facilitates data transmission across various network types.
The middleware layer manages storage, processing, and analysis of data flows.
The application layer delivers domain-specific services and user interfaces.
The business layer generates actionable intelligence and integrates with enterprise systems.

What is the perception layer, and what are its primary functions?

The IoT perception layer is the critical interface between the physical world and digital IoT systems. As shown in Figure 2, it collects environmental data through diverse sensors such as temperature, humidity, motion, light, GPS, cameras, and RFID readers. These sensors monitor physical parameters and convert them into digital data. Additionally, it enables physical control through actuators such as smart plugs, relays, motors, locks, and valves.

Figure 2. Sensors are used in the Perception Layer of the five-level IoT architecture. (Image: ResearchGate)

This layer incorporates embedded systems like Arduino, ESP32, and Raspberry Pi microcontrollers (Figure 3) that manage sensors and actuators. It often runs specialized operating systems like Linux, FreeRTOS, or Zephyr. The perception layer serves as the system’s sensory apparatus, capturing real-world conditions and providing the foundation for all subsequent IoT processing and control functions.

Figure 3. An illustration of how the perception layer in the form of sensors/camera interacts with a Raspberry Pi in the IoT ecosystem. (Image: ResearchGate)

What are the key constraints of the perception layer, and how do they influence the overall IoT architecture?

The perception layer operates under three fundamental constraints: limited processing power, restricted memory capacity, and energy limitations (most devices being battery-powered). These constraints shape the entire IoT architecture.

These limitations necessitate specialized low-power communication protocols (Bluetooth LE, Zigbee, LoRaWAN) designed to minimize energy consumption while maintaining connectivity in the network layer. At the middleware layer, they drive the implementation of edge computing approaches that process data closer to its source, reducing transmission volume and conserving energy.

Furthermore, the heterogeneity of sensor types and data formats requires advanced data management strategies within higher layers, including normalization techniques and filtering mechanisms that transform raw data into usable information. These inherent device limitations influence architectural decisions that balance functionality with practical resource constraints.

What is the network layer in IoT architecture, and what does it do?

The network layer serves as the communication backbone in IoT systems. It reliably transmits data that the perception layer collects to the Processing Layer while enabling control commands to flow in the reverse direction. Figure 4 shows the network layers’ different components, including all the major communication protocols.

Figure 4. The network layer of the five-level IoT architecture comprises cloud back-end, internet security protocol, and communication protocols. (Image: ResearchGate

This layer manages network connectivity, performs addressing and routing, and ensures data integrity and confidentiality during transit. It also handles key functions such as protocol translation, data aggregation, and establishing secure connections across complex network topologies.

What are the key components and technologies in the IoT network layer?

The network layer relies on several key components, including gateways that bridge local device networks with wider networks, routers and switches that direct network traffic, and the underlying physical and wireless infrastructure.

Communication technologies are selected based on specific application requirements and include short-range wireless protocols (Wi-Fi, Bluetooth, Zigbee), low-power wide area networks (LoRaWAN, NB-IoT), cellular networks (4G, 5G), and wired connections like Ethernet.

These physical connections support various communication protocols, from network-level TCP/IP and UDP/IP to application-layer messaging protocols like MQTT, CoAP, AMQP, and HTTP/HTTPS. Specialized protocols such as 6LoWPAN and RPL enable efficient communication in constrained environments.

What architectural considerations are important when designing the network layer?

When designing the network layer, organizations must carefully consider the trade-off between centralized management and distributed risk. While gateways provide essential protocol translation and network integration, they can become single points of failure.

A compromised gateway might expose the entire local network of connected devices, highlighting the importance of robust security measures at these junction points. The architecture must balance the simplicity of centralized aggregation against the resilience benefits of more distributed approaches.

Summary

The perception layer is the first layer responsible for sensing and collecting data from the physical world. The key technologies involved here are sensors, RFIDs, and cameras, to name a few. The network layer is the backbone that enables communication and data transfer between devices and higher-level systems, ensuring interoperability, scalability, and security. The following FAQ will cover the rest of the layers.