Number of Downlink LLC PDUs Discarded due to FLUSH

Measurement Counter

L9509: DOWN_LLC_PDU_FLUSH_DISCARD

Description

When an SGSN finds that an MS changes its serving cell because of cell update or routing area update, the SGSN sends a FLUSH-LL PDU to the original BVC and initiates the following procedure: When the MS initiates the cell reselection in the same NSE (for example, the BSS is an NSE) in a routing area, the DOWNLINK LLC-PDUs with the TLLI in the "original" BVCI (corresponding to the original cell) are deleted or transferred to the "new" BVCI (corresponding to the new cell) related to the current TLLI. When the MS initiates the cell reselection in a different NSE in a routing area, the DOWNLINK LLC-PDUs with the TLLI in the "original" BVCI (corresponding to the original cell) are deleted or transferred to the "new" BVCI (corresponding to the new cell) related to the current TLLI. In this case, if the original BVCI supports inter-NSE re-routing, the LLC-PDU transfer request can be initiated only by the SGSN. When the MS initiates the cell reselection in two different routing areas, the DOWNLINK LLC-PDUs with the TLLI in the "original" BVCI are deleted. This measurement provides the number of downlink LLC PDUs discarded because the BSC receives the FLUSH-LL message in a granularity period.

Unit

Integer number or integer.

Measurement Point

Figure 1 shows the procedure in which the PCU discards a DOWNLINK LLC PDU because it receives a FLUSH LL PDU message from the SGSN. Each time the PCU discards a DOWNLINK LLC PDU because it receives the FLUSH LL PDU message from the SGSN (see measurement point A), the counter is incremented by one.

Figure 1 Discarding downlink LLC PDUs due to FLUSH_LL

Formula

This is an original counter without involving any formula.