Specifications

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Cisco Cable Modem Termination System Feature Guide
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Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System
Configuration Tasks
To verify frequency hopping on the CMTS, see the “Troubleshooting Spectrum Group Characteristics”
section on page 3-36.
Adding a Shared Spectrum Group
To specify that a particular spectrum group is a shared RF spectrum group, use the following command
in global configuration mode:
To verify a shared spectrum group, see “Verifying Spectrum Group Configuration Example” section on
page 3-61.
Command Purpose
CMTS01(config)# cable spectrum-group group-number
hop threshold percent
or
Sets the percentage of all cable modems losing keepalive
messages that will cause a frequency hop. Hop threshold is
the threshold value (expressed as a percentage) of the number
of offline modems identified before the CMTS initiates an
automatic frequency hop.
The frequency hop threshold percentage method prevents a
single failing cable interface from affecting service to other
good cable interfaces. The system does not hop endlessly
because one cable interface is generating 90% of the errors
and 90% of the traffic.
Group-number specifies the spectrum group you are adding
or specifies the spectrum group you want removed from your
router configuration. Valid range is from 1 to 32.
CMTS01(config)# cable spectrum-group group-number
hop period seconds
Sets the minimum time between frequency hops in seconds.
Valid values are from 1 to 3600 seconds. Hop period specifies
the minimum period (in seconds) before which a frequency
hop can occur.
Group-number specifies the spectrum group you are adding
or specifies the spectrum group you want removed from your
router configuration. Valid range is from 1 to 32.
Command Purpose
CMTS01(config)# cable spectrum-group group-number
shared
Specifies a given spectrum group as a shared RF spectrum
group and tells the CMTS that you want to be sure that
upstream frequencies assigned to an upstream port in the
spectrum group are not assigned to any other upstream port in
the spectrum group.
Group-number specifies the spectrum group you are adding
or specifies the spectrum group you want removed from your
router configuration. Valid range is from 1 to 32