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Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide
OL-2239-03
Chapter8 Troubleshooting the System
Performing Amplitude Averaging
cable upstream n power-adjust {threshold [threshold #] | continue [tolerable value] | noise [% of
power adjustment]}
To disable the power-adjustment capability, use the no form of this command:
no cable upstream power-adjust
Syntax Description
Note The threshold default is 1dB. The tolerable value default is 2dB. The power adjustment is 30 percent.
Caution Default settings are adequate for system operation. Amplitude averaging is an automatic procedure. In
general, Cisco does not recommend that you adjust values. Cisco does recommend, however, that you
clean up your cable plant should you encounter flapping CMs.
Note In some instances, you might adjust certain values:
If CMs cannot complete ranging because they have reached maximum power levels, you might try to set
the tolerable value CONTINUE field to a larger value than the default of 2dB. Values larger than 10dB
on “C” versions of cable interface line cards, or 5dB on FPGA versions, are not recommended.
If the flap list shows CMs with a large number of power adjustments, but the CMs are not detected as
noisy, you might try to decrease the percentage for noisy. If you think that too many CMs are
unnecessarily detected as noisy, you might try to increase the percentage.
Setting Frequency Threshold to Affect Power Adjustment
To control power adjustment methods by setting the frequency threshold, use the
cable upstream freq-adj averaging in interface configuration mode. To disable power adjustments, use
the no form of this command.
cable upstream n freq-adj averaging % of frequency adjustment
no cable upstream freq-adj averaging
Syntax Description
n Specifies the upstream port number.
threshold # Specifies the power-adjustment threshold. The threshold range is from 0 to
10dB. The default is 1dB.
tolerable value Determines if the status of the RNG-RSP should be set to CONTINUE or
SUCCESS. The range is from 2 to 15dB. The default is 2dB.
% of power adjustment Specifies the percentage of power-adjustment packets required to switch
from the regular power-adjustment method to the noise power-adjustment
method. Range is from 10 to 100 percent. The default is 30 percent.