Viavi OneExpert CATV 630, Extended Quick Start Manual

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DOCSIS 3.1 Codeword Errors (CWE)
THINGS TO CHECK:
To make sure there are no uncorrectable CWE
 Codeword (CW): a data bucket within a DOCSIS packet
 CW Error (CWE) : a byte-level data packet corruption resulting from
QAM symbol displacement across constellation decision boundaries
 Correctable vs. Uncorrectable determined by number of corrupted
symbols relative to CMTS forward error correction level settings
 If you are having CWEs, you may be losing data

Uncorrectable CWEs indicate dropped packets (think post-FEC
BER)
 Retransmit is required for recovery
 There is no recovery from dropped packets for real-time apps like
VoIP!
 Correctable CWEs are an early warning that the uncorrectable
threshold may be near! (think pre-FEC BER)