Internet of Things (IoT)

Correct Answer: Local device shadows can synchronize device state information locally, allowing devices to communicate and operate with each other.

Local device shadows is the feature that enables local communication between devices, even when internet connectivity is limited or unavailable. It allows devices to synchronize their state information locally, facilitating communication and operation with each other without relying on a constant internet connection. Machine learning inference on edge devices, secure tunneling for remote device management, and automatic over-the-air updates are important features but do not directly address the need for local device-to-device communication when internet connectivity is limited or unavailable.

Correct Answer: AWS IoT Events

AWS IoT Events is the most suitable service to use in combination with AWS IoT Core for real-time data processing and triggering immediate actions based on specific conditions. It allows you to define rules and detect patterns in the IoT data stream, enabling you to trigger alerts or perform actions when certain thresholds are exceeded, such as when a vehicle's engine temperature goes above a specified value. AWS IoT Events integrates seamlessly with AWS IoT Core and provides a way to respond to events in real-time without the need for complex data processing infrastructure. The other options, while useful for certain IoT use cases, are not the best fit for the given scenario that requires real-time event detection and immediate action based on predefined conditions.

Correct Answer: Device Shadow

Device Shadow is the correct answer. AWS IoT Device Shadow is a feature that allows you to store and retrieve the current state of a device, even when the device is offline. It enables you to send commands to devices based on their reported state and desired state. When certain conditions are met, such as receiving specific data from a device, you can update the desired state of the device's shadow. AWS IoT Core will then communicate the desired state to the device when it comes online, triggering the device to adjust its settings accordingly. Device Provisioning is used for registering and onboarding new devices, not for sending commands based on device data. Device Registry and Authentication is responsible for managing device identities and securing the communication, but not for sending commands. Device Gateway and Message Routing is used for receiving and routing messages between devices and AWS services, but it doesn't provide the functionality to send commands based on device state.