Reason for L.NsaDc.SCG.Change.Failure.TNL

Hi Experts,
What are the reason for L.NsaDc.SCG.Change.Failure.TNL, which increased abruplty on top sites from last 3 days.

gNB - SGW transmission issues, packet loss.

I had the same problem here: Check if X2 alarm exist between the site where this alarm appears.
This alarm means that you have a problem with PSCell Change.

Yes, I have checked one site. There is x2 interface fault alarm when issue occur and till now not cleared.

So, you need to solve that first.


I suggest to solve the X2 alarm first. Try to do a PING between CP from Host to Peer.


Using the command you will check the “SCTP Link Failure” and can to check who is the Peer problem in “X2 Interface CP Bearer ID”.

After that, LST SCTPLNK:SCTPNO=X2 Interface CP Bearer ID;

Using this you will have the both IPs (Local and Peer), so, try to do a PING.

Look my result: Problem between both.

Check also if your Counter (N.NsaDc.InterSgNB.PSCell.Change.Fail.Trans) increase.


Thanks @Cesar_Nunes!

If you really have a X2 problem, you´ll probably also have a trouble on this counter:

N.NsaDc.InterSgNB.PSCell.Chance.Fail.Trans: Number of inter-SgNB PSCell change failures caused by transmission faults in LTE-NR NSA DC scenarios.

I Suggest also, check and TURN ON both switches:

LTE_NR_X2_SON_SETUP_SW - GlobalProcSwitch.InterfaceSetupPolicySw (eNodeB side)
X2SON_SETUP_SWITCH - gNBX2SonConfig.X2SonConfigSwitch (gNodeB side)

Hi Cesar, do you know what issue could trigger N.NsaDc.InterSgNB.PSCell.Change.Fail.Conflict ?

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