L9906:CELL_BSSGP_TRAN_RX_FLUSH_LL_PDU_TRANS
This measurement provides the number of times that the PDUs in the buffer are relocated after the BSC receives the FLUSH LL PDUs in a granularity period. This measurement is used to distinguish the intra-BSC or inter-BSC cell reselection from the route update. In the process of cell reselection, if the FLUSH LL PDUs sent from the SGSN to the BSC contain the information about the target cell (the target cell is controlled by this BSC), the LLC PDUs in the buffer are relocated to the target cell so as to maintain the downlink services.
Integer number or integer.
The following figure shows the process where the SGSN sends a FLUSH LL PDU to the BSC. In a granularity period, every time PDUs in the buffer are discarded after the BSC receives a FLUSH LL PDU message (see measurement point A in Figure 1), the counter is incremented by one.
This is an original counter without involving any formula.