RLE Status (DVB-RCS2)

There are two types of traces in the Trace > Data > Demod menu that display component carrier data: CCn (component carrier is fixed), and Display CC (component carrier is dynamically selected using the Carrier Aggregation > Selected CC for Trace Display parameter). See About Demod Per-Carrier Trace Types for more information.

The RLE Status trace shows the SDUs recovered from the frame(s) plus summary counters for decode problems, so you can see what was decapsulated and diagnose failures. For DVB-RCS2, RLE (Return Link Encapsulation) decapsulation runs automatically on traffic bursts.

RLE Status is a type of Matrix Table that provides selectable column visibility and copy/paste and export functionality to share rows of content or complete tables to applications like email, text editing or spreadsheet programs.

Four aggregate counters are shown above the RLE Status table:

Total SDUs — Number of RLE SDUs found in the frame(s).
Fragmented SDUs — Count of SDUs whose ALPDU was carried in more than one PPDU 1) IEEE 802.11: PHY (formerly PLCP) protocol data unit or 2) DVB-RCS2 (RLE): payload adapted PDU (start, continuation, and end fragments), including reassemblies that did not complete or that failed their integrity check. Compare with Total SDUs to see how many SDUs arrived unfragmented.
Frame CRC Cyclic Redundancy Check Failures — Count of Frame PDU (protocol data unit) The data unit exchanged between peer entities of the same protocol layer. On the downward direction, it is the data unit generated for the next lower layer. On the upward direction, it is the data unit received from the previous lower layer. CRC failures.
ALPDU Integrity Failures — Count of reassembled SDUs whose trailer (CRC-32 or sequence number) failed.

The RLE Status table has one row per SDU:


SDU index within the result.	Decode status of the SDU: Not Present — a complete SDU carried in a single payload adapted PDU (PPDU), so it has no RLE trailer; its integrity is covered by the Frame CRC. Normal state for an unfragmented SDU, not an error. Passed — the SDU was reassembled and its trailer (CRC-32 or sequence number) passed. Failed — the SDU's trailer was checked and failed (corrupt data). Truncated Packet — a PPDU declared a length that ran past the frame, so it was discarded. Reassembly Preempted — a new fragment stream started for the same fragment id before this SDU finished (its end fragment was lost), so the partial SDU was discarded. Malformed End — the SDU's end fragment was too short to contain the trailer, so the SDU was discarded. Length Mismatch — the reassembled SDU's length did not match the total length declared in its header, so the SDU was discarded. Invalid Length — a PPDU could not be parsed (a start fragment too short to hold its header fields). No Start — a continuation/end fragment was seen with no in-flight start. Expected and common when you begin demodulating partway through a stream (the start was before the capture). Consecutive such fragments of the same SDU are collected into a single row, with Fragments showing how many were seen. No End — a reassembly was started but the capture ended before its end fragment arrived.	RLE fragment id (reassembly key, 0–7) tying this SDU's row to its fragments. *** for a full (unfragmented) SDU and for signaling frames, which have no fragment id.	Number of fragments the SDU was reassembled from.	Bit offset of the SDU within the decapsulated stream (Meas BER Bit Error Ratio - A ratio of the number of errors to data bits received on a digital circuit. Bits). *** on rows that recover no payload.	SDU length, in bits. *** on rows that recover no payload.	Index of the first frame in which a fragment of this SDU was seen.	Index of the last frame in which a fragment of this SDU was seen.	RLE Protocol Type (hex); *** when suppressed or unknown.	ALPDU label type (0–3); *** when unknown.	Implicit FPDU payload label (hex), packed most-significant byte first. Decoded only when Payload Label Size is set to a nonzero value for the section. *** when the size is 0 (the default), and for label sizes of 7 bytes or more, which are shown as not applicable rather than as a truncated value.

SDU #

Integrity

Fragment ID

Fragments

Offset (bit)

Length (bit)

First Frame

Last Frame

Protocol Type

Label Type

Payload Label

SDU index within the result.

Decode status of the SDU:

Not Present — a complete SDU carried in a single payload adapted PDU (PPDU), so it has no RLE trailer; its integrity is covered by the Frame CRC. Normal state for an unfragmented SDU, not an error.
Passed — the SDU was reassembled and its trailer (CRC-32 or sequence number) passed.
Failed — the SDU's trailer was checked and failed (corrupt data).
Truncated Packet — a PPDU declared a length that ran past the frame, so it was discarded.
Reassembly Preempted — a new fragment stream started for the same fragment id before this SDU finished (its end fragment was lost), so the partial SDU was discarded.
Malformed End — the SDU's end fragment was too short to contain the trailer, so the SDU was discarded.
Length Mismatch — the reassembled SDU's length did not match the total length declared in its header, so the SDU was discarded.
Invalid Length — a PPDU could not be parsed (a start fragment too short to hold its header fields).
No Start — a continuation/end fragment was seen with no in-flight start. Expected and common when you begin demodulating partway through a stream (the start was before the capture). Consecutive such fragments of the same SDU are collected into a single row, with Fragments showing how many were seen.
No End — a reassembly was started but the capture ended before its end fragment arrived.

RLE fragment id (reassembly key, 0–7) tying this SDU's row to its fragments. *** for a full (unfragmented) SDU and for signaling frames, which have no fragment id.

Number of fragments the SDU was reassembled from.

Bit offset of the SDU within the decapsulated stream (Meas BER Bit Error Ratio - A ratio of the number of errors to data bits received on a digital circuit. Bits). *** on rows that recover no payload.

SDU length, in bits. *** on rows that recover no payload.

Index of the first frame in which a fragment of this SDU was seen.

Index of the last frame in which a fragment of this SDU was seen.

RLE Protocol Type (hex); *** when suppressed or unknown.

ALPDU label type (0–3); *** when unknown.

Implicit FPDU payload label (hex), packed most-significant byte first. Decoded only when Payload Label Size is set to a nonzero value for the section. *** when the size is 0 (the default), and for label sizes of 7 bytes or more, which are shown as not applicable rather than as a truncated value.