- This topic has 20 replies, 1 voice, and was last updated 5 years ago by Pix.
5th November 2013 at 08:20 #69302LLmeGuest
I am having problems with few cells where number of unsuccessful RRC establishments is unusally high ( counter: pmTotNoRrcConnectReq, vendor: Ericsson ), but at the same time I don’t have any unsuccessful CS or PS RRC establishments ( counters pmTotNoRrcConnectReqCs and pmTotNoRrcConnectReqPs are both zero ). I haven’t found any other counters to determine which kind of traffic could be having problems during RRC establishment, so if you could help me determine what is causing this fails?
LLme5th November 2013 at 19:13 #69303pixGuest
pmTotNoRrcConnectReq shows the number of RRC requests, not the failures !!
Of course pmTotNoRrcConnectReq is very high, it represents all the RRC requests in your cell.
The failures are shown by the difference between pmTotNoRrcConnectReq and pmTotNoRrcConnectReqSuccess
You can also find all the subcauses of failures below :
rrc denied adm
rrc fail after adm
regards6th November 2013 at 10:50 #69304LLmeGuest
Hi pix, thank you for your answer!
Yes, you are right, difference between pmTotNoRrcConnectReq and pmTotNoRrcConnectReqSuccess
is high, not the counter pmTotNoRrcConnectReq alone.
I have checked counter pmNoFailedAfterAdm and realise that it’s value is almost the same as difference between pmTotNoRrcConnectReq and pmTotNoRrcConnectReqSuccess on that problematic day.
What are the most common reasons for failed RRCs and RABs after admission?7th November 2013 at 05:26 #69305pixGuest
Thanks a lot for sharing your issue here, it’s very interesting.
Failure after Adm are a pain in the a$$…. Did it increase suddenly, or was it always high ?
Possible causes :
1/ TN issue (Iub)
2/ RNC issue (sw issue)
3/ Core network issue
Try doing a Iub lock + cold restart of the RBS.
Also, please show the values for one day, so I can have a better understanding.
pmxh cell=… afteradm|pmTotNoRrcConnectReq -m 4 -a
If the RBS Restart did not work, then GPEH traces are the next step.
So let me recap:
1/ sudden increase ?
2/ share pmx results
3/ do a iub lock + rbs cold restart
pix8th November 2013 at 08:33 #69306LLmeGuest
unfortunately, Iub lock and restart did not help.
The increase was sudden, it started 10 days ago, and jumped from 90 to 400 a day.
Here are the stats:
Start Time: 2013-11-07 08:15:00 End Time: 2013-11-08 08:00:00
LL8th November 2013 at 21:49 #69307pixGuest
In your output, I can’t see the counter related to the failures. Maybe i’m wrong with the name. “aftAdm” perhaps ?
It contains the string “RRC” 🙂
Could you do it again with the counters, including the one i’m talking about ?
Also include all counters related to:
pix22nd November 2013 at 12:39 #69308LLmeGuest
That’s the problem, I’m not sure what counters are you talking about exactl:)
I am calcualting failed RRCs as:
Failed CS RRCs as:
and failed PS RRCs as:
So, for example, newest stats are:
Start Time: 2013-11-22 05:30:00 End Time: 2013-11-22 09:15:00
which means there are:
7310-6356=954 failed RRCs,
770-769=1 failed CS RRC,
706-704=2 failed PS RRCs.
Other stats you’ve asked for:
LL23rd November 2013 at 10:08 #69309pixGuest
Ok great 🙂 Let me go back to work on monday and i’ll give you the names of the counters that are used to classify “failure after adm”.
Because there are only 900 fails, which are all happening on RRC “signalling” (not CS, not PS), I strnogly expect a real radio issue. Signalling usually occurs at cell border, where radio conditions are the worst.
Please ensure you didn’t change any neighbours parameter, utranrelation parameters or that a neighbour is not down.
On monday, we will perform some kpi collection. the best would be to perform some traces (gpeh), but anyway, i’ll do my best with counters.
regards25th November 2013 at 10:04 #69310LLmeGuest
In the meantime, another cell is also having similar problems. But, it’s degradation started on the day we have increased number of HsPdschCodes to 15. Is there any corelation between this and the number of unsuccessful RRCs for signalling?28th November 2013 at 20:52 #69311pixGuest
no, it’s not related.
In your shoes, i would just do a gpeh trace, extract a failure after adm, and see the cause 🙂 That takes one hour and then you’re done !
In your previous pmx extract, it’s a pity you didn’t put the number of fail after adm. In a previous post though, you stated it is equal to the number of rrc failures.
And i told you the main causes for fail after adm : it is a RNC or transport network or Core Network issue.
Have you chercked your RNC load ? Maybe the RNC is in overload ?
GPEH would tell you all that. If you have no decoder for gpeh trace, i can help (but take a very small trace : 30mn in one worst site + CM export).
Cheers2nd December 2013 at 11:26 #69312LLmeGuest
RNC is over-dimensioned, it shouldn’t be the problem.
I’ve done a gpeh trace, but I don’t know how to analyze it, what to search for? Ive never used it before. Regarding adimssion, I have only found this event: INTERNAL_ADMISSION_CONTROL_RESPONSE.2nd December 2013 at 18:57 #69313pixGuest
you can share it somewhere (file share)
and give me the link there : firstname.lastname@example.org
you must also share your CM export from the oss (common explorer ; click on the RNC where you did th trace ; right click ; export NE ; Radio Only, Compressed Mode)
You give me the gpeh files + this CM, and i can analyse them, i’ve got a tool.
pix14th December 2013 at 16:25 #69314SuzaneGuest
Fow which system you guys are facing this Problem, Pix Please share the Outcome of this study..
Thanks,Suzi15th December 2013 at 21:15 #69315pixGuest
it’s on ercisson system.
any input from your side?
we had some issues exchanging the gpeh files, and now the files are good but i have not ime to look at them…
pix12th March 2014 at 03:35 #69316jetlogsGuest
Hi pix what could be the cause of utran rejection.upon reading thr docs about it,it seems to be a little bit broad.and what can be done to reduce this?thanks