An IoT Hub name must be unique across which space?

An IoT Hub name must be unique across all Azure IoT Hub names. This means that when creating a new IoT Hub, the name you choose cannot be the same as any existing IoT Hub in the entire Azure IoT Hub space. This requirement ensures that each IoT Hub can be distinctly identified and accessed without confusion.

This uniqueness is crucial because IoT Hubs are often accessed through URLs that include their names, and if two hubs had the same name, it could lead to conflicts and errors in data transmission and control commands. Therefore, while the name does need to be unique within your Azure subscription, the specific requirement extends to all IoT Hubs globally.

Choosing a name that is unique across all Azure IoT Hub names helps maintain organizational clarity and access reliability, which is fundamental in IoT solutions that often involve numerous devices and potentially multiple hubs.