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
Verifying Frequency Hopping Using an RF Tone Generator
To verify frequency hopping using an RF tone generator, first verify that the upstream is performing
properly. Then inject a tone to the upstream port at the current upstream frequency and cable modem
power level.
For example, if the upstream frequency is 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 (such as 24.0 MHz).
If you do not have an RF tone generator, use another line 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 c3/0, install c4/0 and connect both
upstreams together using a combiner. If the upstream frequency of c3/0 is 22.4 MHz, set c4/0 to
22.4 MHz while c4/0 is carrying traffic. This should force c3/0 to change the frequency to the next
configured value.
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 percent.
Troubleshooting Spectrum Group Characteristics
To troubleshoot the configuration, make sure that you entered a valid spectrum group number, time,
frequency, and input power level. Also, when defining your spectrum, use the following guidelines:
• Avoid frequencies with known ingress problems, such as amateur radio bands or short-wave bands.
• Avoid hostile spectrum below 20 MHz.
• Allow extra bands for frequency hopping.
• Place upstream ports in the same combiner group in a shared spectrum group.
• Use the receive power level setting to perform slight equalization adjustments.
Advanced Spectrum Management Configuration Tasks (Cisco uBR7200 Series)
The following sections describe the configuration tasks that are needed to configure the Cisco uBR7200
series router for the Intelligent and Advanced spectrum management features that are available when
using the Cisco uBR-MC16S cable interface line card.
• “Configuring Spectrum Groups” section on page 3-37
• “Configuring Dynamic Upstream Modulation” section on page 3-39
• “Configuring Proactive Channel Management” section on page 3-40
• “Verifying the Spectrum Management Configuration” section on page 3-41
Note Do not use the commands in this section to configure the Cisco uBR10012 router with the
Cisco uBR-LCP2-MC16S cable interface line card. Instead, use the instructions given in the “Advanced
Spectrum Management Configuration Tasks (Cisco uBR10012)” section on page 3-44.