PDA

View Full Version : pmNoFailedAfterAdm, ExceptionCode = 521



scatter
2012-03-02, 03:50 AM
Hello Experts,

I am back again with another interesting problem.

We have this E/// RNC with 190 cells. Lightly load one. The issue is present in the network for one year now, living across different software upgrades for both RNC and NodeBs.
This happens for both RBS3000 and RBS6000.

We see the exceptionCode = 521, which the RRC setup timer expirty in random cells in RNC. In a given day, there might be no cells having this problem or we will have 1 to 3 cells with the issue. When the exception 521 happens the counter PmNoFailedAfterAdm is stepped. For instance i have given an example below from today:


Object Counter 09:00 09:15 09:30 09:45 10:00 10:15 10:30 10:45 11:00 11:15 11:30 11:45 12:00 12:15 12:30 12:45
UtranCell=TKRAAB pmNoFailedAfterAdm 38 38 38 39 38 39 39 39 39 37 39 38 39 29 38 39

This cell did not have any problem yesterday. After sometime the issue disappears and may appear again after some days. When we check the RRC counters, its the RRC connection request with PS registration thats failing most of the times. When this happens, there is approx 30% degradation to RRC. no impact to RABs. After few hours the problem goes away.

We also observed that certain UEs when they fail, they continue to fail with RRC connection setup procedure. Today we a P-TMSI camped in the cell for more than 5 hours, continuously sending RRC connection request message to RNC, but there is no RRC connection setup complete message from UE. We think that this can be a UE fault. But since the UE is having a P-TMSI, it might have accessed the network before successfully via IMSI and got the P-TMSI allocated by SGSN.

This is the night mare.

At the moment we are thinking of drive test with TEMs recording. But the crazy part is the issue pops up out of the blue in some random cell and dissappears.
There is no faulty boards in RBS,
No iub congestion,
No synch problem,
No transmission problem,
No capacity problem,
No ul interefernce,
No RNC Device load.....


Any suggestions will be appreciated.....

Regards

sekit
2012-03-02, 04:23 PM
Try to check channel elements congestion if you have a large number of pmNoFailedAfterAdm .

electron
2012-03-02, 06:54 PM
Hello Experts,

I am back again with another interesting problem.

We have this E/// RNC with 190 cells. Lightly load one. The issue is present in the network for one year now, living across different software upgrades for both RNC and NodeBs.
This happens for both RBS3000 and RBS6000.

We see the exceptionCode = 521, which the RRC setup timer expirty in random cells in RNC. In a given day, there might be no cells having this problem or we will have 1 to 3 cells with the issue. When the exception 521 happens the counter PmNoFailedAfterAdm is stepped. For instance i have given an example below from today:


Object Counter 09:00 09:15 09:30 09:45 10:00 10:15 10:30 10:45 11:00 11:15 11:30 11:45 12:00 12:15 12:30 12:45
UtranCell=TKRAAB pmNoFailedAfterAdm 38 38 38 39 38 39 39 39 39 37 39 38 39 29 38 39

This cell did not have any problem yesterday. After sometime the issue disappears and may appear again after some days. When we check the RRC counters, its the RRC connection request with PS registration thats failing most of the times. When this happens, there is approx 30% degradation to RRC. no impact to RABs. After few hours the problem goes away.

We also observed that certain UEs when they fail, they continue to fail with RRC connection setup procedure. Today we a P-TMSI camped in the cell for more than 5 hours, continuously sending RRC connection request message to RNC, but there is no RRC connection setup complete message from UE. We think that this can be a UE fault. But since the UE is having a P-TMSI, it might have accessed the network before successfully via IMSI and got the P-TMSI allocated by SGSN.

This is the night mare.

At the moment we are thinking of drive test with TEMs recording. But the crazy part is the issue pops up out of the blue in some random cell and dissappears.
There is no faulty boards in RBS,
No iub congestion,
No synch problem,
No transmission problem,
No capacity problem,
No ul interefernce,
No RNC Device load.....


Any suggestions will be appreciated.....

Regards






Hi friend,

Actually this problem is not just from your network. i can say more and less you can observe in all 3G network . Most probably problem is coming form transport party. So in this case i suggest you to check AAL2 congestion or performance for different class ( I did not do it practically ). also some time issue is coming due to RBS hanging try to restart the NodB and trace the performance . It's normal to have it rarely. So sine as you mentioned your network is not loaded a slight degradation will show very dramatic in statistics which you can justify it due to low load

banquos_ghost
2012-03-02, 08:06 PM
Is it possible to preconfigure GPEH with RRC (request, setup, setup_complete) and Internal Release events.
Then, when the problem occurs, to activate the events for that cell