Basic Internet of Things (IoT) Architecture

IoT encompasses a wide range of applications, but most systems share a common architectural framework. While the idea of every IoT device being directly connected to the internet may seem appealing, it's not practical in most cases. There are several reasons why IoT architectures typically avoid giving each sensor or actuator its own internet connection.

1. Resource Constraints:
   Small, battery-powered sensors often lack the processing power to handle complex protocols like TCP/IP, let alone secure protocols such as HTTPS. These devices are designed to be lightweight and energy-efficient, which limits their capabilities.
2. Cost Efficiency:
   Even devices like relays, which don't face strict power constraints, need to remain cost-effective. Adding the processing power necessary for direct internet connectivity increases the device's complexity and price.
3. Wireless Communication Limitations:
   Many IoT devices rely on wireless communication. Supporting a full TCP/IP stack for transmitting small data packets over shared wireless channels is inefficient and costly.

Star Topology: The Preferred IoT Model

Due to these constraints, most IoT systems use a "star" topology. In this setup:

• End Devices (sensors, relays, etc.) communicate wirelessly with a centralized IoT Hub.
• The Hub acts as a bridge, forwarding data from the end devices to the internet and vice versa.

This indirect approach allows the use of lightweight, local communication protocols between the hub and end devices, optimizing performance and reducing costs.

Local Area Protocols

Popular local communication protocols include:

• ZigBee
• Z-Wave
• Bluetooth Low Energy (BLE)

These protocols are designed for low-power, short-range communication, making them ideal for typical IoT applications.

For applications requiring long-range communication, LoRa (Long Range) is an option. However, LoRa is more complex and expensive, making it suitable for specific use cases like smart agriculture or industrial IoT.

Special Case: Cameras

IoT cameras present unique challenges due to the high bandwidth required for video streaming. As a result, they typically use Wi-Fi or Ethernet for connectivity. This highlights another crucial role of the hub: integrating various networks and protocols into a single system.

The Role of the Hub

The IoT hub serves as the central node in the architecture. It:

• Aggregates data from different types of end devices.
• Translates between local protocols and internet protocols.
• Forwards data to cloud servers or other internet services.

This architecture ensures efficient communication while keeping IoT devices affordable, simple, and power-efficient.