Installation guide

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Cisco uBR7100 Series Universal Broadband Router Software Configuration Guide
OL-2238-03
Chapter 3 Configuring the Cisco Cable Interface
Configuring and Activating Frequency Agility
> 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
Care should be taken to reduce the spectrum allocation when used with small channel widths. Otherwise,
there will be a large number of upstream channel slots.
For example, if the allocation is from 20.0-to-28.0 MHz and an upstream port has its channel width set
to 0.2 MHz, there are 40 possible slots for that channel width. Blind frequency hopping can require a
long time to find the clean slot, because it tries each available slot, one at a time for several seconds
during each try.
Verifying Spectrum Group Configuration
To verify if spectrum groups are configured and activated, enter the show cable spectrum-group
command:
CMTS01# show cable spectrum-group
22:07:46: %SYS-5-CONFIG_I: Configured from console by console
Group Frequency Upstream Weekly Scheduled Power Shared
No. Band Port Availability Level Spectrum
(Mhz) From Time: To Time: (dBmV)
1 5.000-15.000 0 Yes
1 12.000 0 Yes
1 22.000 7 Yes
2 29.000 6 No
2 26.000 0 No
3 35.000-41.000 0 No
3 16.000-19.000 5 No
5* 5.000-10.000 Thu 21:50:00 Thu 21:45:00 0 Yes
Verifying Frequency Hopping
To verify frequency hopping on the Cisco uBR7100 series CMTS, note the following:
• The controller must report being up.
• The comparison of the number of errors versus the number of error-free packets is a measure of the
link quality. The percentage of errors should be less than 1%.
After you have established basic operation, inject a tone to the upstream port. For example, if the
upstream frequency is currently 22.4 MHz, inject a 22.4 MHz tone at approximately the same power
level as the modem. If the power level at the modem is 40 dBmV, set the tone power to 40 dBmV. The
interfering carrier should shut down the channel and cause the frequency to change to the next configured
value. In this example, it would be 24.0 MHz.
If you do not have an RF tone generator, use another cable modem card and modem that carries traffic.
Connect the upstream to the same combiner group, and use the data carrier as an interfering signal by
setting it to the same frequency. For example, to test frequency hopping on c1/0, install c1/0 and connect
both upstreams together using a combiner. If the upstream frequency of c1/0 is currently 22.4 Mhz, set
c1/0 to 22.4 MHz while c1/0 is carrying traffic. This should force c1/0 to change the frequency to the
next configured value.