A cell has a deep drop in CSSR level. Monitoring the statistic, I found that the sdcch allocation attemps was increasing while the MS establishment amount was the same. Firstly, I thought it is a phantom RAch but with more investigation i found that there was a huge increase in sdcch attemps to do location update!
What is the reason of the CSSR reduction?
note that the reduction is due to the big difference between the number of sdcch attemps and the number of ms sdcch establishment.
I posted a reply earlier, but it didn’t go thru this firewall from hell.. so just a quick reply
1. your CSSR : does it include SDCCH for LU ? it is a weird choice. It should just include origin. and termin. calls, isn’t it ?
2. high nuber of LU : is there a site (from another operator ? or from the other side of your lac brder ?) which has been going down and up ? massive amount of people can switch from one lac to another one in this situation
3. when are the peaks in LU load ? all over the day ?
too much LUs can create SDCCH congestion, which might block the call setup… but that must be a lot of LU…