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Cisco Broadband Cable Command Reference Guide
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Chapter 2 Cisco CMTS Configuration Commands
cable upstream threshold
cable upstream threshold
To configure the upstream for the carrier-to-noise ratio (CNR) and Forward error correction (FEC)
threshold values to be used in determining the allowable noise levels, use the
cable upstream threshold
command in cable interface configuration mode.
cable upstream
n
threshold
cnr-profile1
threshold1-in-dB
cnr-profile2
threshold2-in-dB
corr-fec
fec-corrected
uncorr-fec
fec-uncorrected
Note
This command can be used only on upstreams on the Cisco uBR-MC16S cable interface line cards.
Syntax Description
Defaults
The CNR threshold for the primary modulation profile defaults to 25 dB. The CNR threshold for the
secondary modulation profile defaults to 15 dB. The correctable FEC error threshold defaults to
3 percent of total packets received, and the uncorrectable FEC error threshold defaults to 1 percent of
total packets received.
Note
The ranges and defaults for the correctable and uncorrectable FEC error thresholds were changed in
Cisco IOS Release 12.2(8)BC2.
Command Modes
Interface configuration (cable interface only)
n
Specifies the upstream port number. Valid values start with 0 for the
first upstream port on the cable interface line card.
cnr-profile1
threshold1-in-
DB
Specifies the CNR threshold for the primary modulation profile
specified for the upstream. The threshold is specified in dB (5–35,
default is 25).
cnr-profile2
threshold2-in-
DB
Specifies the CNR threshold for the secondary modulation profile
specified for the upstream. The threshold is specified in dB (5–35,
default is 15 dB and must be less than the primary threshold).
corr-fec
fec-corrected
Specifies the allowable number of correctable FEC errors for the
upstream. The
fec-corrected
parameter is given as a percentage of total
packets received on the upstream during the polling period, with a valid
range of 1 to 30, and a default of 3.
uncorr-fec
fec-uncorrected
Specifies the allowable number of uncorrectable FEC errors for the
upstream. The
fec-uncorrected
parameter is given as a percentage of
total packets received on the upstream during the polling period, with a
valid range of 1 to 30, and a default of 1.
Note
For normal plant use, Cisco recommends that the uncorrectable
FEC threshold remain at its default of 1 percent to avoid an
unacceptable number of errors on the channel.