Response from Gateway is not received to nodes

[ObaidAshraf]

Hello, I am new to the OpenThread and stuck at a problem.

I am trying to create an OpenThread communication using MQTT-SN with RPI and nRF52840 device. So far I am able to create an OpenThread network and the nRF52840 node is able to JOIN the Gateway. I also verified ipv6 ping between GW (border router) and nRF node and also I am able to ping Google DNS from the node. I followed the OpenThread codelab (https://openthread.io/guides/border-router/raspberry-pi). My RaspberryPI has internet on its WLAN0 interface.

Now I am running nordic MQTT-SN subscriber example by with Paho MQTT-SN Gateway. I build the Paho MQTT-SN Gateway (using https://github.com/eclipse/paho.mqtt-sn.embedded-c/tree/master/MQTTSNGateway) and also made changes for BrokerName, GatewayUDP6IP and set Port to 47193. I executed the MQTT-SNGateway binary and started monitoring the logs.

The problem is when the nRF node searches for Gateway, it always return with "No Gateway found" .. By looking at the terminal, I can see that Paho binary has received "SearchGW" message from a client (the nRF) and it has also sent GWINFO response message. But I am not receiving any message in the nRF. I am added multiple LOGs at different places in the MQTT-SN Subscriber example specially at listening side but no log appears regarding any message being received.

Any help in this regard?

[jwhui]

Can you provide a packet capture trace for analysis in Wireshark?

[jwhui]

Route to fd00:0:fb01:1::/64 via wpan0 interface appears in the Linux routing table.

Are you able to ping fd00:0:fb01:1:7274:f422:e9b9:7940?

If the ping works, then I would say there's an issue with the MQTTSN gateway implementation.

[ObaidAshraf]

@jwhui
I am able to ping the nRF client from both Linux and ot-ctl utility. What issue in MQTTSN gateway implementation are you suspecting? Is it something related to MQTTSN itself?? or can it be some configuration related error?

[jwhui]

MQTTSN log indicates that it is sending a packet, but tcpdump does not show the packet

Unfortunately, I do not have any experience with MQTTSN, so I cannot help there.

[ObaidAshraf]

Hey @jwhui
Just to let you know that I have resolved the issue. The problem was the incorrect BrokerName in Paho MQTTSN Gateway's gateway.conf file. After fixing the problem, the nRF node received the GWINFO message and other messages.
Thanks for the help.

[jwhui]

Glad you have it working. Thanks for the update!