UEContextReleaseCommand from MME with cause:nas:normal-release

Hello Friends.

Getting UEContextReleaseCommand from MME with cause:nas:normal-release, after approx 4 seconds, of handover command to the UE.

What could be the possible scenario you can think of here?

Might be expiry of S1RelocOverall timer.

Is handover successful at target cell?

Handover notify was sent by target BTS to MME?

Target cell traces not available.

Handover failure case.

For sure.

HO was over x2.

I mean preparation.

Then “UEContextReleaseCommand from MME with cause:nas:normal-release” is normal behaviour.

It is result of handover failure and the cause.

Find cause from UE logs.


Does it mean UE is lost, what timer play role here for release from MME?

Has source eNb send UE context release request to MME?

I guess yes. Please confirm.

This looks like X2RelocOverall case not S1relocOverall case since you mention X2 handover.

No Source eNB has not sent any such request.

I think, that UE has done re establishment after HO failure and failed, and then attempted a new session, but since the context was already in source eNB, so the MME clears old context.

Where RRE happened?

Source eNB or target?

Not at source, no logs on this.

I am trying to guess the scenario.

Yes this may be the case then.

But MME cause is normal, actual cause HO failure.