- This topic has 3 replies, 1 voice, and was last updated 9 years, 5 months ago by Alonewılves.
24th August 2011 at 09:34 #67006AlonewolvesGuest
My question is related to PS side.
i have noticed that some cell have high PS assignment failure ratio.
here is the observation points:
1- everyday the same cells suffering from the problem
2- Those Cells suffer this problem for some period . not whole day , ie. between 13:00 to 15:00 and 20:00 to 21:00
3- i am sure there is GPRS/EDGE trafic on cell, i have check GPRS/EDGE Throughput daily basis
4- PS Assignment Failure ratio is %100 for mention period.
5-EDAP configuration are correct and TRXS and sectors are GPRS/EDGE enabled, cross-connection are properly configured. Traffic manager is ok.
( all setting are correct because sectors gives gprs/edge services , i can see PS throughputs )
6- BTS is Nokia Ultrasite Software Version 7.0
What do you advise , what to check to troubleshoot the problem.
Regards.25th August 2011 at 09:03 #67007alonewolvesGuest
Any suggestion ? looking forward hearing you soon25th August 2011 at 12:13 #67008pixGuest
when failure is 100%, the problem always come from a faulty HW.
Now, i don’t know Nokia systems, but you might want to check the PCU (packet control unit) congestion or processor overload. Under extreme stress, I assume defense mechanisms are activated (tbf assign reject?). Also, maybe it’s your BTS processing unit that’s overloaded.
I have no other suggestions… check interfaces congestions as well (ater, abis, Gb)
I don’t think the core network (SGSN) could be the problem here.
Again, i would say that’s either a BTS or a PCU HW problem.
pix28th August 2011 at 13:40 #67009AlonewılvesGuest
Although Nowadays i don’t have any cell that has %100 PS assignment failure rate,
but a cell has high PS Assign. Failure rate every day changng from %30 to %50
Accourding to formula :
1- (The number of the PACKET_IMMEDIATE_ASSIGNMENT messages/The number of packet channel requests on CCCH)
in CELL-1 NACK for ps assignment message is “0”,
so i confused in here
if NACK for PS assign. message is 0 ,
accourding to formula PS failure rate needed to be 0 as well
Site has 3 Cells,
Cell 1 and 2 share the same EDAP pool,
Sector 3 has individual EDAP pool,
i have expected to have similar PS assignment problem for cell 2, which shares EDAP pool with cell 1,
Cell-2 does not have this kind of problem. i assume that problem is in the BTS side.
Could you please comment on this isuue ,
Here some additional information regarding to Cell
No Congestion On:
Related Frame Relay has little congestion
EDAP has congestion but almost the same rate with other cells’
Default and dedicated GPRS values are the same for all cells.