Neighbor eNodeBs connected to different MMEs

Hi Gents.

If we have 2 LTE eNBs (eNB-A & eNB-B) neighbouring to each other.

While eNB-A is connected with 2 MMEs in pool & eNB-B is connected with one MME only.

We don’t have choice to add 2nd MME at eNB-B.

There would be HO failure due to MME mismtach?

How can we restrict the failures in this scenario?

Please consider Nokia equipment.

If someone can help in parametric tuning etc…

MME 1 and MME 2 don’t have a connection?

Why it should be a problem?

Context to be shared to new MME.

2 MMEs are in pool.

UE moves to new eNodeB connected MME 2 as eNodeB has only connection to that so.

I don’t see any problem.

M8014C5 - LTE Inter eNB Handover degradation.
It is the exact counter affected.

Are you able to see handover completion time?

Additional delay.

This counter represents handover via X2.

1 Like

Failed Inter-eNB Handover preparations caused by other reasons.

The counter is updated if the failure detected does not match any other failure counter.

I think it is a counter issue, should not be a impact on user.

do you have any logs or pcaps to see s1ap/x2ap signaling?

Could be counter issue,

Could be counter issue, but how to control it?

If we match the MMEs count then counter reduces to zero.

We are suspecting S1 traffic is involved in this failure.

Hmm… I see there is a timer for handoverpreparation for intermme

Increase that.

Is there any way that we isolate one MME in HO procedure?

Target PCI RSRP stronger in the end it will trigger handover to target eNB connected to MME 2.

I think it is about timers you set.

Check S1 based ho timers, if it is short and expring before air interface moved to target, this counter can be pegged.

It means S1 timer should be higher than X2?

For sure.

Can you please let me know S1 timer related MME?

ts1relprepL, ts1erabmodInd

  • ts1relprepL = 500ms
  • ts1erabmodInd = 2000ms

ts1relprepL = 500ms we are using the same, but all eNBs have the same MME config, you can increase and observe the counter.

OK , will try and update results. Thank you!