Trying to publish MQTT-SN message with Zephyr and Openthread

RE: Trying to publish MQTT-SN message with Zephyr and Openthread

Maria Gilje — Tue, 17 Oct 2023 19:09:11 GMT

Hello,

I have taken over this case while Sigurd is away.

Thank you for sharing that you have made some progress and for answering Sigurd's questions.

I had a read through your original ticket together with the MQTT-SN specification v1.2, and I found that some messages have a weird format. I am thinking of the ones with "double lined" arrows from the following log:

[quote user=""]mqtt-sn paho log
[/quote]

The message format is not according to spec. Do you know where the format is from?

[quote user="krypton76"]In order to succeed i completely clean the RPI from scratch without any docker services, and any network rules.

Based on that i rebuilt an mqtt-sn paho server, and i have badly the same results : i'm able to connect and start register but i get any callback calls.[/quote]

I assume that you meant that you did not get any callbacks?

By comparing the Wireshark screenshot to the Paho log it seems that two UDP messages are missing in the Paho log (packets 3563 and 3564). Do you know which messages these could be? What does their frames look like?

If you have any new logs to share after the change you made, please share them.

RE: Trying to publish MQTT-SN message with Zephyr and Openthread

krypton76 — Mon, 09 Oct 2023 12:33:30 GMT

So thanks for helping me.
For the record, since last time i succeeded in sending a simple coap message on a simple python coap server that is running on RPI ans forwarding the message to cloud mqtt service.
In order to succeed i completely clean the RPI from scratch without any docker services, and any network rules.

Based on that i rebuilt an mqtt-sn paho server, and i have badly the same results : i'm able to connect and start register but i get any callback calls.

And to answer you i'm able to ping online ip adresses :

uart:~$ ot ping 8.8.8.8
Pinging synthesized IPv6 address: fd2b:2a9b:18d6:2:0:0:808:808
16 bytes from fd2b:2a9b:18d6:2:0:0:808:808: icmp_seq=2 hlim=114 time=23ms
1 packets transmitted, 1 packets received. Packet loss = 0.0%. Round-trip min/avg/max = 23/23.0/23 ms.
Done

RE: Trying to publish MQTT-SN message with Zephyr and Openthread

Sigurd Hellesvik — Fri, 06 Oct 2023 12:11:08 GMT

[quote user="krypton76"]You 're right this is a choice i made, my prior objectives is to work on MQTT network, with a "regular" IOT network. I think that MQTT-SN is the default one that can synchronise natively with other MQTT network.
I'm not so confident to use COAP. I May end with CoaP and a synchronisation process to send messages between MQTT and COAP.
The other point is that MQTT-SN get native functions (that i won't implement for now) to handle messages asynch with sleeping objects.[/quote]

I talked to some colleagues, and I now understand better that MQTT in many cases advantageous. We will help you debug your issues as best we can.

First, I want to check a couple of basic things, but an important thing to know still:

Is you OTBR connected to the internet?

Are you able to ping online IP addresses from your thread device?

RE: Trying to publish MQTT-SN message with Zephyr and Openthread

krypton76 — Mon, 02 Oct 2023 16:19:13 GMT

You 're right this is a choice i made, my prior objectives is to work on MQTT network, with a "regular" IOT network. I think that MQTT-SN is the default one that can synchronise natively with other MQTT network.
I'm not so confident to use COAP. I May end with CoaP and a synchronisation process to send messages between MQTT and COAP.
The other point is that MQTT-SN get native functions (that i won't implement for now) to handle messages asynch with sleeping objects.

I already tried several mqtt configurations (even without docker, in native RPI mode) and i get the same behavior, even <ith the one you suggested.
I used paho mqtt-sn mosquitto rsmb and https://github.com/eclipse/mosquitto.rsmb.
every time i get a connexion entry with CONNACK in broker serer log, but CONNACK never get back to client (i assume it would displays something in evt_cb callback function.

I just changed something with no luck : i call mqtt_sn_input in a loop just after the connexion, but it never raise any events in the evt_cb function.

RE: Trying to publish MQTT-SN message with Zephyr and Openthread

Sigurd Hellesvik — Mon, 02 Oct 2023 13:53:22 GMT

Hi,

I know it is not the answer you want, but let us first take a step back:
Why have you chosen MQTT-SN instead of CoAP here?

CoAP does not require anything extra on the OTBR, and we have more support for it.

It is of course up to you, I just want to try to suggest the alternative I think is easier. Also, I am curios for use-cases where MQTT-SN is preferrable.

For the MQTT-SN issue, I suggest you startby isolating the issue: Is it the nRF or the OTBR.
Can you test this OTBR also, and see if the same issue is still there? https://github.com/osaether/otbr-mqtt-sn
If so, there is a higher chance that the issue is on the nRF somewhere.