PS Call Release due to GTPU Loss

[gprastomo]

Hi,

I dont have any experience about core PS, and week ago, we move our SGSN (Huawe) to New SGSN (Huawe), RNC also Huawe.
And suddenly we have huge number of PS Rab release due to GTPU.
Also our PS Core team, doesnt have any experience about this.
Do you have any idea, what should i check in SGSN ?

br

[boring]

what is actually the problem?
a RAB cannot be established or active RABs are released because of GTPU issue?
any traces from IuPS and Gn interfaces would greatly help!

[gprastomo]

Rab accessibility is ok.
But PS RAB Active mostly are release due to GTPU Loss.

[boring]

from the moment that GTPU is establshed then there is no reason for CN to release it.
only i could think is some kind of capacity limitation at SGSN or perhaps some inactivity timers expire?
where do you see this problem. at the stats of the RNC? stats at SGSN? or from traces?

[gprastomo]

Sorry there was some mistakes about the GTPU counters, it is the abnormal release counter suddenly increase. And in the same time the IRAT PS was degraded when the SGSN moved to the new SGSN.
Perhaps this due to IRAT problems. No problem with the inactivity.

Any suggestion about the IRAT in the SGSN point of view ?

br

[boring]

i had a look for GTPU failures, and Huawei says this is due to hardware problem. unfortunately, i couldn't find anything else...

now regarding the SGSN. the only case that new SGSN affects IRAT PS is due to problematic configuration and provisioning. e.g. something is not configured correctly betwwen 2G-SGSN and 3G-SGSN.

you see during PS IRAT, the RNC orders the UE to go to GPRS where the UE does a RAU and the 2G-SGSN communicates with the 3G-SGSN in order to forward the UE context. is it possible to get any traces in order to pinpoint the issue?

[gprastomo]

Hi thanks,

They just replied, that there is problem on the Charging, that on specific subscriber suddenly have drop of connection due to charging issue, the Charging thinks that this subscriber doesnt have enough credit, so the charging drop the connection (low thruput). Let s see ...
For IRAT , they are investigating now, it is due to others.

[Fado]

Hi thanks,

They just replied, that there is problem on the Charging, that on specific subscriber suddenly have drop of connection due to charging issue, the Charging thinks that this subscriber doesnt have enough credit, so the charging drop the connection (low thruput). Let s see ...
For IRAT , they are investigating now, it is due to others.
how you found that it is from core?which counter you checked?
thanks!

[sabila]

how you found that it is from core?which counter you checked?
thanks!
check the statistic of error
if u used MSS NSN may the fail is C0A Service or Facility Usage Restricted.

Dear om Gprastomo,
1.may u check alarm GTPC tunnel broken for this case?
2.check ping ,delay,packetloss in front of router front of SGSN using vrf Gn

[dfindme]

Hi Prastomo,
i have experience abnormal increase gtpu loss,
the problem on Direct tunnel(GGSN) one of many ip link has broken or disconnect.
this impacted not to all user.

you should check all link on direct tunnel to ps core engineer.

thanks

Hi,

I dont have any experience about core PS, and week ago, we move our SGSN (Huawe) to New SGSN (Huawe), RNC also Huawe.
And suddenly we have huge number of PS Rab release due to GTPU.
Also our PS Core team, doesnt have any experience about this.
Do you have any idea, what should i check in SGSN ?

br

[senjamir]

Hi Gprastomo,

The IRAT in PS is normally done during the CM mode and it is somehow non continuous unless there is a feature installed that permit the system to HO from HS to GSM. Normally when you have irat failure it can be the 2G system is congested due to lack of TCH for data session due to high CS traffic. Kindly ask your 2G RF counterpart to check the accessibility in the RF side in terms of data traffic.

In case they find some congestion then the problem is in the RF.

Br,
Sen