Multiple connections to IoT Hub devices

Question

Multiple connections to IoT Hub devices

Slava A 106

This is related to https://learn.microsoft.com/en-us/answers/questions/148853/restrictions-on-deviceclient.html
Opening a second connection to a device generates exceptions and both connection don't work.

is it possible for SDK to internally manage connections and automatically disable "old" connection when new connection is created
if one of the connections is closed, the other seems to reconnect and starts to work. is there a timeout associated with this reconnect? or it will try to reconnect until it succeeds?

AshokPeddakotla-MSFT 35,971 Reputation points Moderator

2020-11-18T11:03:25.453+00:00

@Slava A We are looking into this question and update you as earliest.
António Sérgio Azevedo 7,671 Reputation points Microsoft Employee Moderator

2020-12-15T00:36:52.433+00:00

Hello @Slava A ,
Please share with us if you have any other questions related with your original post. Otherwise could you go ahead and mark the below as answer so community members can benefit from a richer content? :)

Thank you so much.
Vithal Wadje 11 Reputation points

2020-12-21T08:20:38.823+00:00

I don't know the reason behind it but with this approach, other connected devices will be got disconnected also every time establishing the connection is very expensive process particularly with AMQP and MQTT , The better way is to generate the sas token for each device instead of re-creating connectionString

3 answers

Your answer

AshokPeddakotla-MSFT 35,971 Reputation points Moderator

2020-11-18T11:03:25.453+00:00

@Slava A We are looking into this question and update you as earliest.
António Sérgio Azevedo 7,671 Reputation points Microsoft Employee Moderator

2020-12-15T00:36:52.433+00:00

Hello @Slava A ,
Please share with us if you have any other questions related with your original post. Otherwise could you go ahead and mark the below as answer so community members can benefit from a richer content? :)

Thank you so much.
Vithal Wadje 11 Reputation points

2020-12-21T08:20:38.823+00:00

I don't know the reason behind it but with this approach, other connected devices will be got disconnected also every time establishing the connection is very expensive process particularly with AMQP and MQTT , The better way is to generate the sas token for each device instead of re-creating connectionString

Answer 1

Hello @Slava A ,

!Please understand that as mentioned in the related thread, the scenario of "opening a second connection to a device" is unsupported and exceptions\errors you receive are expected.

1) is it possible for SDK to internally manage connections and automatically disable "old" connection when new connection is created

If you can recognize the new connection created with the exception or error thrown by the SDK then you can "manipulate" SDK behavior based on that. See 400027 ConnectionForcefullyClosedOnNewConnection

PS: I am validating internally if this also applied when you connect with AMQP transport type.

2) if one of the connections is closed, the other seems to reconnect and starts to work. is there a timeout associated with this reconnect? or it will try to reconnect until it succeeds?

It will retry based on the retry policy: https://github.com/Azure/azure-iot-sdk-java/blob/master/device/iot-device-client/devdoc/requirement_docs/com/microsoft/azure/iothub/retryPolicy.md

Thanks!

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António Sérgio Azevedo 7,671 Reputation points Microsoft Employee Moderator

2020-11-27T20:40:04.977+00:00

Hello @Slava A ,
I have confirmed that both AMQP and MQTT closes older connection if a new connection for same device is attempted .

Let me know if you are ok to mark the above as the answer?

Thanks!

Answer 2

Liam Sanchez-Rodriguez 1

Hi, did you solve your issue? I am having the same issue when sending telemetry data from Python SDK on a RaspberryPi 4, and try to receive the cloud-to-device message on the Python SDK running on my laptop, when both connections happen at the same time, both terminals begin to throw 'Connection dropped' errors

Answer 3

Hi Liam

similar to your issue i am also facing, i have to wait for desired property and i need update the reported data & telemetry data every 5 second need to send when i am connecting any two also i m also getting same connection dropped error

exact screen error

"Exception caught in background thread. Unable to handle.
['azure.iot.device.common.transport_exceptions.ConnectionDroppedError: Unexpected disconnection\n']"

if you solve please help me & reply to this

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Multiple connections to IoT Hub devices

3 answers

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