I am new to the world of Azure IoT. I have a requirement for one of my clients. There are multiple firewalls in the client network (Tier-I, Tier-II,Tier-III). The IoT enabled devices to be monitored sit behind the Tier-III firewall. Hence they are planning to provision IoT Edge Device A in Tier-III region and will open the appropriate ports for monitoring the devices. They plan to provision another IoT Edge Device B in the Tier-I region that will be exposed to the internet using Tier-I firewall. The requirement is as follows: IoT Edge Device A to be able to push the collected data points (upstream) to IoT Edge Device B in real-time. • Can support one to many connection (Device A to Device B or any other device/system/application) • One-way data flow only (there will be a unidirectional data diode in place) Is this possible to achieve? Kindly suggest . Thanks Amit

Hello Amit. At this time, no out-of-the-box Edge 2 Edge communication is available. And Edge devices can not act as child devices. This question is quite similar to this one on MS Learn Q&A at first sight. in that case, passing data between edge devices, you should do: writing two modules (one on each device) which use an alternative protocol, picking up messages from the A route and putting it back on the B route. There should be no usage of $upstream in device A. But this only works when both devices are connected to the internet (at least once) so the security and deployment manifest and module twins can be set. After that, device A could be used without an actual internet connection but it will not be updated anymore because it's out of reach of the IoT Hub.

IoT edge device A able to push data to IoT Edge Device B

Accepted answer

Sander van de Velde 30,016 Reputation points MVP

2020-08-28T15:21:47.3+00:00
Hello Amit.

At this time, no out-of-the-box Edge 2 Edge communication is available. And Edge devices can not act as child devices.

This question is quite similar to this one on MS Learn Q&A at first sight.

in that case, passing data between edge devices, you should do:

writing two modules (one on each device) which use an alternative protocol, picking up messages from the A route and putting it back on the B route. There should be no usage of $upstream in device A.

But this only works when both devices are connected to the internet (at least once) so the security and deployment manifest and module twins can be set.

After that, device A could be used without an actual internet connection but it will not be updated anymore because it's out of reach of the IoT Hub.
Please sign in to rate this answer.

1 person found this answer helpful.
Amit Mukherjee 31 Reputation points

2020-08-29T07:05:30.837+00:00

Thanks Sander for your kind inputs. By alternative protocol do you mean any protocol other than MQTT,AMQP or HTTP?.

I have one additional question, normally using Visual Studio Code and by the help of Azure IoT tools extension, we can view the live telemetry data from Aure IoT Hub. Is there any other way to view the telemetry data right in the IoT Edge Box or from the offline IoT Hub?

Thanks

Amit Mukherjee 31 Reputation points

2020-08-29T07:30:18.053+00:00

My apologies for posting another follow-up question that came up to my mind later.

IoT Edge devices are meant to work offline or on-premise with little or no internet facility. In this case, the client wants to provision IoT Edge Device A at the Tier-III firewall zone. This is a zone without internet access. So, will it be possible to achieve this ? From my understanding, every IoT edge device has a device twin and module twin created in Azure IoT Hub. But for that we need to have an internet connection. Does that mean although IoT edge devices are meant to work offline, yet they need an internet connection atleast once for synching with the online Azure IoT Hub?

Really sorry again to be asking too many questions but just wanted to be clear with the basic concepts.

Regards
Amit

Sander van de Velde 30,016 Reputation points MVP

2020-08-29T17:43:23.427+00:00

I recommend looking at protocols like MQTT. AMQP, or Websockets.

These are stateful and are providing the Publisher-Subscriber pattern so these are easy (proven libraries are available in multiple languages) and reliable.

Sander van de Velde 30,016 Reputation points MVP

2020-08-29T18:02:29.413+00:00

These are all great questions :-)

Tldr; Yes, an (outbound) internet connection is needed for the updates.

It is totally fine to run an IoT Edge device offline. It only needs an internet connection once to get everything in place (the security and getting the deployment manifest with the information and the configuration of all the modules to run).

In Azure IoT Edge, from a device perspective, the Device Twin has no meaning. Both as a developer or administrator you can not pass desired properties or direct methods to the Device. In IoT Edge, this is all integrated into the Module Twins of the modules running on the device. These are the pieces of logic you program and deploy and manage.

And of course, send D2C messages requires an internet connection too.

So if you want to update the device (sending a new deployment manifest, sending module twin updates, or executing (direct) methods on the module) you need an internet connection. If not, it will keep working offline.

Amit Mukherjee 31 Reputation points

2020-08-30T10:34:41.363+00:00

Thanks Sander for your invaluable inputs....:)
Sign in to comment

Share via

IoT edge device A able to push data to IoT Edge Device B

0 additional answers