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
Configuring Spectrum Groups
Frequency hopping cannot be done without first creating one or more spectrum groups, which define the
specific frequencies that are available to an upstream. A spectrum group can contain a range of
frequencies as well as a list of specific frequencies. This allows efficient frequency hopping, so that
upstreams can avoid frequencies that have known interference and other ingress noise problems.
To configure a spectrum group with a range of frequencies, use the following procedure:
Command Purpose
Step 1
Router(config)# configure terminal
Enters configuration mode.
Step 2
Router(config)# cable spectrum-group
group-number [ day time hh:mm:ss ] band
up-freq-hz up-freq2-hz [ power-level-dbmv ]
Creates a spectrum group and specifies a range of frequencies
that belong to the group.
group-number = Spectrum group number. Valid range is 1 to 32.
Configuring a spectrum group with multiple entries of this type,
defines a list of frequencies that are available for use as
upstream frequencies.
day and time hh:mm:ss = (Optional) For scheduled spectrum
groups, specifies the day of the week (Sun–Sat) and the time of
day that the frequency and input power level should change.
band up-freq-hz up-freq2-hz = Sets the band of frequencies for
this spectrum group. The valid range for up-freq-hz and
up-freq2-hz is 5,000,000 to 42,000,000 Hz, but up-freq2-hz
must be greater than up-freq-hz.
power-level-dbmv = (Optional) Nominal input power level.
Valid range is –10 to +10 decibels per millivolt (dBmV), with a
default of 0 dBmV. Some cable plants might want to change
only the input power level and not frequency on a daily time
schedule.
Note When configuring a band of frequencies, specify a band that is 500 KHz larger than the largest desired
channel width, to ensure that the largest channel width can still be used when changing the center frequency
within the band.
Step 3
Router(config)# cable spectrum-group
group-number hop period seconds
Specifies the minimum time in seconds between frequency
hops for the spectrum group. The default value is 25 seconds.
Step 4
Router(config)# interface type slot/port
Configures the interface where:
type = cable
lot = slot number in chassis (slot numbers begin with a 0)
port = port number on cable modem slot (port numbers begin
with a 0)
Step 5
Router(config-if)# cable n spectrum-group y
Enters interface configuration mode, and assigns the upstream
port to the frequency hop table for the associated spectrum
group.
Step 6
Router(config-if)# cable upstream port
spectrum group y
Assigns upstream ports individually. Valid only for
Cisco uBR-MC16S card.
Step 7
Router(config-if)# exit
Exits configuration mode and force the system to hop.