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Cisco uBR10012 Universal Broadband Router Software Configuration Guide
OL-1520-05
Chapter6 Troubleshooting the System
Performing Amplitude Averaging
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
The following example shows how to change the power-adjustment method when the frequency
adjustment packet count reaches 50 percent:
Router(config-if)# cable upstream 0 freq-adj averaging 50
Syntax Description
nSpecifies the upstream port number.
averaging Specifies that a percentage of frequency-adjustment packets is
required to change the adjustment method from the regular
power-adjustment method to the noise power-adjustment method.
% of frequency adjustment Specifies the percentage of frequency-adjustment packets required to
switch from the regular power-adjustment method to the noise
power-adjustment method. Valid range is from 10 to 100 percent.