Question: Upon reception of a STATUS report from the receiving RLC AM (Acknowledged Mode) entity, what action does the transmitting side of an AM RLC entity take if the STATUS report acknowledges the RLC SDU with sequence number equal to POLL_SN and timer t-PollRetransmit is running?
Option 1: Start timer t-PollRetransmit for potential retransmission.
Option 2: Ignore the STATUS report and continue transmitting new SDUs.
Option 3: Stop and reset timer t-PollRetransmit.
Option 4: Send an additional STATUS report to confirm receipt.
Explanation: When the transmitting side of an AM RLC entity receives a STATUS report that includes an acknowledgement (positive or negative) for the RLC SDU with a sequence number matching POLL_SN, and if the timer t-PollRetransmit is currently running (indicating a pending retransmission check), the appropriate response is to stop and reset this timer. This action is logical because the receipt of an acknowledgement for the sequence number in question (POLL_SN) indicates that the SDU has been successfully received, thereby negating the need for potential retransmission checks signaled by t-PollRetransmit.