What's the difference between "Reliability" and "Speed" modes when e.g. performing OTA updates with the Simplicity Connect (Si Connect) mobile app from Silicon Labs?

Answer

In summary, both modes leverage Bluetooth Low Energy (BLE) and make use of the Generic Attribute Profile (GATT) protocol, a communication framework that sets standardized rules for how two – or more – devices connect, interact, and exchange data. For example, it structures data into services, each with specific, defined characteristics. Simply put: "Reliability" Mode prioritizes secure, error-free data transfer, while "Speed" Mode emphasizes fast, real-time performance, allowing you to choose the best fit for your application needs.

Reliability Mode: Uses Write with Response, where each packet is acknowledged to ensure reliable and accurate data transfer. Ideal for critical updates like firmware upgrades, it prioritizes data integrity over speed, making it suitable for scenarios where errors are unacceptable.

Speed Mode: Uses Write Without Response instead, resulting in faster data transfer by skipping acknowledgments. While it does not guarantee delivery, it is preferred for non-critical updates, such as sensor data or telemetry, where speed is more important than reliability.