nRF9151 DECT NR+ – PT association fails with MAC_STATUS_NO_RESOURCES (7) using official dect_shell sample

Hello,

I am currently testing DECT NR+ communication between multiple nRF9151 SMA DK boards, but I am unable to establish a connection between an FT and a PT.

I initially observed the issue with my own application, so I decided to reproduce the test using the official Nordic dect_shell sample without any modifications.

Unfortunately, I can reproduce the association problem with the official sample as well.

Environment

Hardware: nRF9151 SMA DK (multiple boards available for testing)
nRF Connect SDK: v3.4.0
Zephyr OS: v4.4.0-bf801e4e3d19
Sample: nrf/samples/dect/dect_shell
Board target: nrf9151dk/nrf9151/ns
DECT NR+ modem firmware: mfw-nr+_nrf91x1_2.0.0
Region: EU
Band: 1

I configured one board as FT with Long RD ID 1 and another board as PT with Long RD ID 2.

FT configuration

dect sett --reset

dect sett -t 1 --dev_type FT

dect activate

dect connect

The FT successfully creates the network:

NET_EVENT_DECT_RSSI_SCAN_RESULT
RSSI scan result:
  Channel:                             1657
  All subslots free:                   yes
  Busy percentage:                     0%

NET_EVENT_DECT_CLUSTER_CREATED_RESULT
Cluster started/reconfigured at channel 1657.
FT: network created

NET_EVENT_DECT_NETWORK_STATUS:
  Network status: created

dect status reports:

DECT NR+ status:
  Modem FW version:             mfw-nr+_nrf91x1_2.0.0
  Modem activated:              yes
  Cluster running:              yes
  Cluster channel:              1657

I also tested starting the network beacon explicitly.

PT configuration

I first deactivate the modem before resetting/changing the settings:

dect deactivate
dect sett --reset
dect sett -t 2 --dev_type PT
dect activate
dect connect

The PT appears to discover the FT correctly, because it identifies Long RD ID 1 as its Parent, but the association fails with:

NET_EVENT_DECT_ASSOCIATION_CHANGED
 DECT_ASSOCIATION_REQ_FAILED_MDM:
  Association request failed in modem with long RD ID: 1
  Neighbor role:                                       Parent
  Modem cause:                                         No resources (7)

Network creation failed: 7 (No resources)

NET_EVENT_DECT_NETWORK_STATUS:
  Network status: failure 7 (No resources)

<err> dect_mdm: Modem operation failed for Association Response
with err MAC_STATUS_NO_RESOURCES (7) with long RD ID: 0x1

What is interesting is that immediately after this failure, dect cluster_info on the FT reports:

Cluster status information:
  Cluster channel:                 1657
  Number of Association requests:  0
  Number of Association failures:  0
  Number of neighbors:             0
  Number of FTPT neighbors:        0
  Number of received RACH PDCs:    0
  Number of RACH PCC CRC failures: 0

dect neighbor_list on the FT also reports:

No neighbors found.

Therefore, from the PT side it looks like the FT is discovered (Long RD ID 1 / Parent), but the association procedure fails with MAC_STATUS_NO_RESOURCES (7), while the FT does not appear to receive an association request at all.

I have multiple nRF9151 SMA DK boards available and can reproduce the issue after resetting the DECT settings. The boards are using the same modem firmware.

Could you please clarify:

What exactly does MAC_STATUS_NO_RESOURCES (7) mean during PT association in this context?
Is mfw-nr+_nrf91x1_2.0.0 the correct/recommended modem firmware for the dect_shell sample in NCS v3.4.0?
Is there any additional FT configuration required before a PT can associate (Network Beacon, RACH resources, association settings, etc.)?
Should the official dect_shell sample work with the simple FT/PT procedure above without any additional configuration?
Are there any additional modem/debug logs I can enable to determine why the PT reports NO_RESOURCES?

I can provide complete logs from both the FT and PT, as well as test with a third nRF9151 SMA DK if needed.

Thank you.

Parents

0 Simon D-M 1 day ago

Hi,

I just tried to replicate your issue on my DKs and for me, it worked fine...

FT:

desh:~$ dect deactivate 
DECT NR+ stack de-activation initiated.
De-activation done
NET_EVENT_DECT_DEACTIVATE_DONE: de-activation done
desh:~$ dect sett --reset
Settings updated.
desh:~$ dect sett -t 1 --dev_type FT
Settings updated.
desh:~$ dect activate
DECT NR+ stack activation initiated.
Activation done
NET_EVENT_DECT_ACTIVATE_DONE: activation done
desh:~$ dect connect
connect initiated.
NET_EVENT_DECT_RSSI_SCAN_RESULT
RSSI scan result:
  Channel:                             1657
  All subslots free:                   yes
  Busy percentage:                     0%
NET_EVENT_DECT_RSSI_SCAN_DONE: scan done
NET_EVENT_DECT_CLUSTER_CREATED_RESULT
Cluster started/reconfigured at channel 1657.
FT: network created
NET_EVENT_DECT_NETWORK_STATUS:
  Network status: created
[00:12:07.915,649] <wrn> dect_mdm: handle_mdm_rssi_complete: no IPv6 prefix to set - using link local only
NET_EVENT_DECT_ASSOCIATION_CHANGED
 DECT_ASSOCIATION_CREATED:
  Association created with long RD ID:                 2
  Neighbor role:                                       Child
[00:12:36.614,776] <wrn> net_l2_dect: No global IPv6 address to set - using link local only
desh:~$

PT:

desh:~$ dect deactivate
DECT NR+ stack de-activation initiated.
De-activation done
NET_EVENT_DECT_DEACTIVATE_DONE: de-activation done
desh:~$ dect sett --reset
Settings updated.
desh:~$ dect sett -t 2 --dev_type PT
Settings updated.
desh:~$ dect activate
DECT NR+ stack activation initiated.
Activation done
NET_EVENT_DECT_ACTIVATE_DONE: activation done
desh:~$ dect connect
connect initiated.
NET_EVENT_DECT_ASSOCIATION_CHANGED
 DECT_ASSOCIATION_CREATED:
  Association created with long RD ID:                 1
  Neighbor role:                                       Parent
PT: Joined a network
NET_EVENT_DECT_NETWORK_STATUS:
  Network status: joined
[00:14:00.376,037] <wrn> net_l2_dect: No global IPv6 address to set - using link local only
desh:~$

So, I'm not exactly sure what is happening with your setup.

Did you tweak anything in the application, and how did you build it (any extra kconfig/overlay)?

Can you maybe share your compiled application so that I can try to run it on my DKs and see if this is an issue with the application or the DKs?

And here is the application I compiled (tfm_merged.hex), please try to program this one to your DKs and check if that works.

What exactly does MAC_STATUS_NO_RESOURCES (7) mean during PT association in this context?

I haven't looked into details yet, so I'm not 100% sure. But It looks to be some kind of complain that there is not enough free space in the memory to handle a new connection.

But I don't think you are trying to handle multiple connections at the same time here. And only 1 connection should be a walk in the park for the application.

Is mfw-nr+_nrf91x1_2.0.0 the correct/recommended modem firmware for the dect_shell sample in NCS v3.4.0?

Yes, this is the same one as I used.

Is there any additional FT configuration required before a PT can associate (Network Beacon, RACH resources, association settings, etc.)?

I think you can leave the rest by default as when I tried your commands, it worked on my end.

Should the official dect_shell sample work with the simple FT/PT procedure above without any additional configuration?

From what I can see in my test, yes it should work.

Are there any additional modem/debug logs I can enable to determine why the PT reports NO_RESOURCES?

We would be able to see more if you share the full logs. And maybe even more if you enable the modem trace. But, before doing so, it would be better to just try to isolate where the issue is (DK, mfw, app, build, commands, ...).

Best regards,

Simon

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