Receive messages delay issue about iotedge-lorawan-starterkit

[zhaozhenhong5]

Yes,I am monitoring a single device using VsCode. I can only see the messages of a single one.
If single gateway can connect 500 devices,that will be good,if not ,that will be two or more.

[fbeltrao]

Hi,

Could you please provide your LoRaWanNetworkSrvModule logs?
Which region is your IoT Hub? What is your latency to Azure Cloud?

[zhaozhenhong5]

Now I found the engine can work well with one device sending messages every 1 second. But 2 or more would show that delay issue.

My IoT Hub location is East US,and I used the lorawan US region to change into CN470.(But the downstream can't work well now)
OK，you can see my LoRaWanNetworkSrvModule test logs here:
I need the Azure Cloud latency is as less as possible. In fact,I need about 500 devices work sending messages every 5 second.

[fbeltrao]

Hi,

Thanks for the information and logs.

We tested the solution with multiple devices and haven't experience the problem you have. In order to help us troubleshoot the problem could you please make a few changes and try again with multiple devices?

Changes

1. In your leaf devices please remove the property "SensorDecoder". Your payload seems to be in binary format causing problems in the value decoder "Invalid JSON returned from 'DecoderValueSensor'"

2. Disable for now cloud to device message by editing the class IoTHubConnector replacing ReceiveAsync with (we have a pending task to make it easier in the future):

public Task<Message> ReceiveAsync(TimeSpan timeout) => Task.FromResult((Message)null);

3. Build, push and deploy the solution

4. Test with 3 devices are you had before

5. Publish the logs and results

Additional questions:

• You are monitoring a single device using VsCode, aren't you? In that case you would only see the messages of a single one, not from the remaining 2
• Is your intention to connect all 500 devices to a single gateway?

If you wish we can have a call to discuss your scenario and give your more information about the project.

[zhaozhenhong5]

I have changed the code just like this:
` public async Task ReceiveAsync(TimeSpan timeout)
{
return await Task.FromResult((Message)null);
/* try
{
CreateDeviceClient();

            deviceClient.OperationTimeoutInMilliseconds = 1500;

            setRetry(true);

            Logger.Log(DevEUI, $"checking c2d message", Logger.LoggingLevel.Full);

            Message msg = await deviceClient.ReceiveAsync(timeout);

            Logger.Log(DevEUI, $"done checking c2d message", Logger.LoggingLevel.Full);

            setRetry(false);

            return msg;

        }
        catch (Exception ex)
        {
            Logger.Log(DevEUI, $"Could not retrieve c2d message with error: {ex.Message}", Logger.LoggingLevel.Error);
            return null;
        }

*/ }`
But the delay problem can't solved.You can see the log here

I think we should make a call as soon as you online.I can get your email and add your skype(email adress?).

[fbeltrao]

After our call, switching to IoT Hub direct connection on the Network Server removed the delay.

Follow up:

• provide guidelines on how to configure direct connection to IoT Hub
• implement deactivation flag for C2D message on device level
• investigate delay in IoT Edge device telemetry

[zhaozhenhong5]

Yes,thank you. The delay problem is solved perfectly.