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.

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

Also, check it: DSP X2INTERFACE:QUERYTYPE=FAULT_TYPE-1;

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.

2 Likes

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)