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 Examples
Because the group is shared, ports U2 and U3 will be assigned channels 1 and 4, respectively, to prevent
overlap.
Note There are no alternate frequency assignments for either port, and bandwidth is wasted from 24.8 to 26.0
MHz. To create alternate channels, increase the upper boundary from 26.0 to 28.0 MHz.
> Channel Width Start Stop Center
> (Mhz) (Mhz) (Mhz) (Mhz)
> 1 3.2 20.0 23.2 21.6
> 2 3.2 23.2 26.4 24.8
> 3 1.6 20.0 21.6 20.8
> 4 1.6 21.6 23.2 22.4
> 5 1.6 23.2 24.8 24.0
> 6 1.6 24.8 26.4 25.6
> 7 1.6 26.4 28.0 27.4
Try to reduce the spectrum allocation when it is used with small channel widths. Otherwise, there will
be a large number of upstream channel slots, and the frequency hopping may require several minutes to
find a clean slot.
Other Spectrum Management Configuration Examples
To configure differing spectrum groups, refer to the following examples:
• Use the following example to add time-scheduled spectrum. You can add spectrum on a weekly
schedule by including an optional weekday and time:
Router(config)# cable spectrum-group 1 time Mon 08:00:00 frequency 21600000
Use the delete keyword to delete the frequency:
Router(config)# cable spectrum-group 1 time Mon 18:00:00 delete frequency 21600000
• Use the following example to configure spectrum group 1 with an upstream frequency of
6,500,000 Hz and a default power level of 0 dBmV:
Router(config)# cable spectrum-group 1 frequency 6500000
• Use the following example to add the upstream frequency 7,000,000 Hz to the list of valid
frequencies with a default power level of 0 dBmV for spectrum group 1:
Router(config)# cable spectrum-group 1 frequency 7000000
• Use the following example to configure spectrum group 2 with an upstream frequency 7,500,000 Hz
and change the power level to 5 dBmV:
Router(config)# cable spectrum-group 2 frequency 7500000 5
• Use the following example to configure spectrum group 3 with an upstream band of 12,000,000 to
18,000,000 Hz and default power level of 0 dBmV:
Router(config)# cable spectrum-group 3 band 12000000 18000000
• Use the following example to add the upstream band 20,000,000 to 24,000,000 Hz to the list of valid
bands with a change in the power level of 13 dBmV for spectrum group 3:
Router(config)# cable spectrum-group 3 band 20000000 24000000 13