As I am learning, the IoT Edge's main usage is to process the data coming from various child devices and to send the data back upstream which is IoT Hub. In this way, we can reduce the data sent to IoTHub. And the edge device can be any Virtual Machine on the cloud or an On-premise device like Raspberry Pi inside the factory.
If we use an On-premise device we can send sensor data to it, and it can store those data locally if there is no internet.
So my question here is if I use VM as an IoT Edge device, don't I still need the internet to send data to those VMs? In that case, how does the offline functionality works? Will I be able to send the data to the IoT Edge device if there is no internet?
In a real world scenario, your edge device is installed close to the devices from where you want to collect telemetry. In other words, the edge device will be on the same local network as your sensors (otherwise, we wouldn't call it an edge device). When the edge device is in the same network as the devices that collect telemetry, the telemetry is not sent over the internet to your edge device.