A real 5G NR attach capture shows the radio link sending the same RLC packet twice, on two separate occasions. Not one status report in the trace names a missing packet. The full walkthrough follows RLC acknowledged mode on both bearers, the signaling bearer and the data bearer, and explains why.
What the capture shows
RLC stays readable on a ciphered link. The capture is NEA2-ciphered, but ciphering is a PDCP function, so RLC's sequence numbers, segmentation fields, and poll bit are in the clear on every frame. The payload is not.
Sequence numbers count SDUs, not transmissions. A capability report cut into three segments keeps one sequence number and costs one line in the status report.
The poll bit follows the buffer, not a clock. Signaling polls on nearly every PDU, while the data bearer polls only at the end of a burst. One cumulative ACK_SN then closes the whole burst.
Both retransmissions are timer-driven. Two polls went unanswered as their connections ended, and each resend followed 44.9 ms later. That interval matches the TS 38.331 default t-PollRetransmit, a value nothing in the trace ever configures.
The walkthrough covers both bearers end to end, including segmentation, cumulative acknowledgment, and the diagnostic habit the retransmissions teach.
Full walk-through: https://www.eventhelix.com/5G/nr-attach-air-interface/rlc-nr-acknowledged-mode/
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