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Cisco Broadband Cable Command Reference Guide
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Chapter 2 Cisco CMTS Configuration Commands
cable spectrum-group (global configuration)
Usage Guidelines
Frequency agility is configured and activated using spectrum groups that are controlled by the spectrum
manager. You can create from 1 to 32, or from 1 to 40, spectrum groups for each cable modem card
upstream port, depending on the Cisco IOS software release.
To create spectrum groups, specify a list of upstream frequencies and nominal power levels that each
spectrum group can use when an upstream frequency change is necessary. Each spectrum group should
have its own list of upstream frequencies. At 1.6 MHz, the valid range is –10 dBmV to 25 dBmV. The
power level value should be changed only if you want to change only the power level as part of spectrum
management. The standard power level is 0 dBmV.
The the
cable spectrum-group
command sets the center frequency for the upstream, but the total
frequency bandwidth that is actually used depends on the channel width.
Table 2-7
shows the possible
center frequencies for each channel width, for both DOCSIS and EuroDOCSIS cable interfaces.
The allowable range for the upstream channel frequency depends on the cable interface line card and
Cisco IOS software release being used. See
Table 2-11
for the currently supported values.
12.0(13)SC, 12.1(4)EC,
12.2(4)BC1
The allowable frequency range was increased to 65 MHz to
support the EuroDOCSIS frequency range of the Cisco uBR-
MC16E cable interface line card.
12.2(15)BC2
The maximum number of spectrum groups was increased from 32
to 40 groups per router.
Release
Modification
Table 2-7
Allowable Center Frequencies
Channel Width (MHz)
Center Frequency (MHz)
DOCSIS (5 to 42 MHz)
Center Frequency (MHz)
EuroDOCSIS (5 to 65 MHz)
200,000
5.1 to 41.9
5.1 to 64.9
400,000
5.2 to 41.8
5.2 to 64.8
800,000
5.4 to 41.6
5.4 to 64.6
1,600,000
5.8 to 41.2
5.8 to 64.2
3,200,000
6.6 to 40.4
6.6 to 63.4
Table 2-8
Allowable Frequency Range for the cable upstream frequency Command
Frequency Range
Supported Cable Interfaces
Minimum Cisco IOS Releases
5 to 42 MHz
All supported cable interfaces
All releases supported for the
Cisco CMTS
5 to 55 MHz
Cisco uBR-MC16U/X and
Cisco uBR-MC28U/X, when
operating with extended
frequencies for Japanese mode
Cisco IOS Release 12.2(15)BC2
5 to 65 MHz
Cisco uBR-MC16E,
Cisco uBR7111E and
Cisco uBR7114E routers
Cisco IOS Release 12.0(13)SC,
12.1(4)EC, and 12.2(4)BC1
