Number of Downlink LLC PDUs Discarded due to Timeout

Measurement Counter

L9508: DOWN_LLC_PDU_TIMEOUT_DISCARD

Description

Each time the BSC receives the PACKET DOWNLINK ACK/NACK message from the MS, the BSC knows which LLC PDU is received successfully and must be deleted from the PDU queue and which DOWNLINK LLC PCU packets are not received successfully and must be stored in the buffer queue. The BSC regularly detects the life cycle of each DOWNLINK LLC PDU in the buffer queue. If the BSC detects that the life cycle of a PDU expires, it discards the PDU and sends an LLC DISCARDED message to the SGSN to request retransmission of the DOWNLINK LLC PDU. This measurement provides the number of downlink LLC PDUs discarded because the life cycle expires in a granularity period. If the value of this measurement is high, you can infer that the transmission performance is poor.

Unit

Integer number or integer.

Measurement Point

Figure 1 shows the process of the BSC discarding a DOWNLINK LLC PDU. Each time a DOWNLINK LLC PDU is discarded due to timeout of the life cycle (see measurement point A), the counter is incremented by one.

Figure 1 Number of downlink LLC_PDUs discarded owing to timeout

Formula

This is an original counter without involving any formula.