openDSME example application does not work reliable out of the box with nRF52840 MDK Dongles

[Lennart-Lutz]

Description

When using the examples/advanced/opendsme example on two nRF52840 MDK USB Dongles (Makerdiary), the non-PAN node consistently loses its link state after a few seconds.
Right after startup, both nodes show state: up and association works. Sending a single message via txtsnd works, but shortly afterward the non-coordinator node switches back to state: down. The behavior also occurs when sending no traffic at all.

This happens with the unmodified example and default configuration.
However, when using the same nodes with the examples/networking/gnrc/networking example, message exchange and RPL works reliable.

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Steps to reproduce the issue

1. Flash the unmodified examples/advanced/opendsme example to two Makerdiary nRF52840 MDK USB Dongles or probably other boards featuring a nRF52840 MCU.
2. Open two terminals and connect to the nodes.
3. On node A (intended PAN coordinator):

   ifconfig X pan_coord (X depends on interface number)
   ifconfig X up
   

4. On node B:

   ifconfig X up
   

5. Observe both ifconfig outputs: initially, both nodes are state: up. (if executed quickly)
6. Optional: send a message

   txtsnd X XX:XX test (XX:XX is the target node adress)
   

   Delivery succeeds (if executed quickly).
7. Wait a few seconds.
8. Even without sending any traffic, node B switches to state: down after a few seconds (<6s).

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Expected results

The non-PAN node should remain associated with the PAN coordinator and keep state: up as long as beacons are received. In my case, the nodes were close together, but not too close.
The default openDSME example should allow a stable two-node setup out of the box.

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Actual results

• Node B shows state: up immediately after ifconfig X up.
• Association appears successful.
• After a few seconds, node B shows state: down
• This occurs: with traffic (txtsnd) and without any traffic.
• On unmodified example code.
• On multiple attempts.

This makes it currently impossible to run the basic openDSME example on two nRF52840 MDK USB Dongles.

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Versions

Operating system: Ubuntu 24.04
RIOT Version: 2026.01-devel-193-g5196b (5196bac)