L9901:CELL_BSSGP_TRAN_RX_FLUSH_LL_PDU
This measurement provides the number of FLUSH LL PDU messages received in a cell in a granularity period. When the SGSN detects that an MS moves to another cell, it sends a FLUSH LL PDU message to the originating cell. This counter indicates the number of times that the MS moves to another cell.
Integer number or integer.
The following figure shows the process where the SGSN sends a FLUSH LL PDU message to the BSC. In a granularity period, every time 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.