Few worst cells having almost 100% contribution of Number of E-RAB setup failures triggered by the MME

Hi Experts.

These are the top 4 worst cells having almost 100% contribution of Number of E-RAB setup failures triggered by the MME.

TA samples % sharing is shown,
Can any one tell how to improve from radio end or what to do basic checks?
Cell down tilted yesterday but no impact

What is cause of ERAB release from MME?
Is issue with rf condition?
Rulled out issue by drive test first if possible.

Alternatively you should collect pcap of s1 which may give exact cauae of release.

Check if issue is due to top UE, check para, or change SRI period.

Also s1 success rate and its attempt and success can be checked.

Thanks, can you share SRI period parameter?
I have requested for traces, let’s see what will come in traces.

At Core end?

KPI can be checked from OSS.
S1 failure and also check eRAB fail due to TNL.
That is signalling connection success / attempt.

Mod pucchcfg:sriperiodadaptive.

MME cause is also due to missing neighbours.
Please see this link to understand how MME drops are related to RF missing neighbours:

S1 failure and TNL failures are fine.

I will get findings and get back. :+1:

Great, let me check this as well. will get back. :wink:

I had high numbers of MME Fails caused by wrong user profiles from Core side.
Also need to check with your Core team if user profiles are correctly configured.

Can wrong MME have this issue? Wrong MME definition?
Like MME1 to MME2 for example, wrongly created?

Can you tell few examples of that issue? Just for reference.

Just high numbers of ERAB Fails due to MME.
And the customer confirmed that new sim cards admitted to the network and not provisioned correctly.

After adjusting profiles configuration it is improved alot.
In Nokia RAN, there are switches to be adjusted.
But Huawei I only faced this user issue.

But here MMEs are defined in pool.

Dsp sctppeer or dspsctplnk, I don’t remember. You can check this commmands, compare two sites.
Is your MME fail in one entire site?

In Huawei there’s too parameters, but I cannot control this much failures.

For ERAB setup failure, you can put trace/packet mirror on s1ap of those eNb.
In trace, reason can be find out.
In MME, trace/ packet mirror need to register.

check if there is external interference or if setup failed with cause {interaction-with-other-procedure} from CHR log

Bro, Please try to understand the Call flow of layer 3 messages that when the
MME sent message " S1 Initial Context Setup Request " to enodeB which contain default bearer "SRB1 QCI 9 request and enodeB sent (1) Security Mode Command & (2) RRC connection Reconfiguration message to UE. This failure occur mainly cause of weak RF coverage of UE or Connection lost but eNodeB unaware of it.
Optimization Action are :
Increase value of N310 and T310
Improve RF coverage.

Only focus on Radio part.

You can check all the possibilities from radio side , check traces any particular cause for MME fails…I also see mme failures increased due to pci confusion… your mme fail count numbers are quite big…check any activities from the day of fails start…you will get it…