S1 link fail in eRAB

4G LTE
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1

Hi Experts.
In eRAB I am getting S1 fail count and eRAN fail due to try signalling. May be reconfiguration complete not happening?
S1 fail is due link issue, can eRAB fail due to rrcsig be due to Core issue?
More failure are due to eRAB due to RRC reconfiguration fail in RRC signal total count.

Any Samsung expert can explain what can cause this fail?
I too have S1 link fail in eRAB.

After reconfiguration there is timeout.
Also after security mode command no complete message.

2

What is your S1 Initial Context Setup Timer in MME?
Also what is the RRC ReConfigurationTimer on the RAN side?

3

It is failing from UE to eNB.
No reconfiguration complete hapepening.
Time out are happening.
I will check that value
In handover we say timer t304.
What is reconfiguration timer called in accessibility eRAB.

4

This timer do not start with “t” in Huawei this is usually set to 25s.

5

Thanks!
I will Check what value is there but eRAB set up delay too will increase, fail will reduce.
What’s parameter name called in Huawei?

6

Is this NAS related security mode command or AS?

7

I guess RRC security mode.
Timeout.
Customer wants access to improve from 99.4 to 99.8.
It’s tough as there are s1 link fail as well as this fail.

8

It is after UE capability so it is AS security.

9

Which is called erabinitnbrfailrrcsigtot.

AS yes.

10

This much delay is within tolerable limits this is the reason Huawei has set all the Uu Interface timers to 25s.

11

I will check in Samsung I guess PUCCH IRC or fixed sri can work too but fixed sri is risky.
I too have worked on Huawei before finding tough on Samsung OSS.
Huawei has good subcounter as compared to Samsung.

12

As per my understanding, In general this could be checked from PDCP layer point of view regarding time out first looks like issue could be in PDCP layer for time out for encryption and ciphering.

13

Thanks @vinod_081. If this is the issue, then what would be your suggestion?

14

Huawei has inactdiscardSwitch, which allows the ongoing signaling flow i.e. reconfig .complete/securitymode complete to not be terminated when timer expires.

Maybe you can try find if Samsung has a similar switch.