Assaignement Failures Causes

[gogotchiya83]

Dear Experts;

In order to improve our CSSR i make a study on the reason of ASS Failures, i Found that 65% of failures are due to Clear Commands Sent By MSC (counter A3129H : HW equipement)

Is it Normal to have this value?
What is the reason that can make the MSC Clear the ASS command?

Regards//
Gogo

[babak1349]

Hi,
As we discuss before this failure happens during assignment and during RAB assignment or TCH assignment , resource allocation by Radio access is done, if there is a problem for example lack of resources (nodeb/BTS HW or resources like as power. code and Transmission resources) or MGW overload you may get assignment failure as well So you need to check the resources first to make sure it doesn't happen because of lack of resources

if it happens in RNC have you checked the following counters:

RAB.EstFailCs.Cell
RAB.EstFailPs.Cell

And also SUB-CAUSES
It is when RAB assignment contain a failure cause

cheers

Cheers

Dear Experts;

In order to improve our CSSR i make a study on the reason of ASS Failures, i Found that 65% of failures are due to Clear Commands Sent By MSC (counter A3129H : HW equipement)

Is it Normal to have this value?
What is the reason that can make the MSC Clear the ASS command?

Regards//
Gogo

[gogotchiya83]

Huawei counterA3129H:Failed Assignments(Clear Commands Sent By MSC)increment whenMSC send release/clear command to BSC too fastbefore BSC send Assignment complete

Any more explanation?

[babak1349]

Hi,
during RAB assignment there are 4 stages of resource allocation
1) AAL2 allocation on Iu
2) NBAP allocation through Radio Link Reconfiguration prepare
3) Iub AAL2 allocation
4) Radio Bearer Setup

Similar flow might be for GSM
So which stage it exactly fails ? It could be during AAL2 allocation over Iub which fails and immediately MSC sends clear message During this stage MGW is involved and if it is loaded system may fails to allocate the resources

Is not better to run trace ?
cheers

Huawei counterA3129H:Failed Assignments(Clear Commands Sent By MSC)increment whenMSC send release/clear command to BSC too fastbefore BSC send Assignment complete

Any more explanation?