Here we are having Ericsson systems (MSC’s,BSC’s and BTS) and this problem is not detectable during drive test….and is not that frequent even..but sometimes during call we observe such problems…so i was just trying to identify the root cause of that…as Error in connection is related to SDCCH congestion when TCH could not be allocated but during call it is not the case also we didnt see any hardware problem in cells where i identified this problem….Can you please explore bit more …..