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Cisco uBR7200 Series MC16S Cable Modem Card Spectrum Management 5

Spectrum Management Conﬁguration Guidelines

This section presents tips, capabilities, and guidelines to keep in mind when conﬁguring the

Cisco uBR7200 series for spectrum management.

General

In general, when deﬁning your spectrum, be sure to take the following into consideration:

• Avoid frequencies with known ingress problems such as amateur radio bands or short-wave

bands

• Avoid hostile spectrum below 20 MHz for use with 16QAM because the cable network does not

support the necessary SNR.

• Allow extra bands for frequency hopping

• Use the receive power level setting to perform slight equalization adjustments

Using the Cisco uBR7200 series cable modem cards and Cisco IOS Release 12.0(7)XR2 CMTS

images, you can conﬁgure the router to:

• Allocate and migrate to a new channel while in session without losing data if a predetermined

threshold is violated

• Perform 15 channel migrations per second

• Use multiple methods to determine the need to change frequencies and multiple approaches

when migrating cable modems to a new channel; each can be conﬁgured and customized

• Migrate frequencies based on the following conditions:

— When using the MC16S cable modem card, if the number of lost station management

messages exceeds a predetermined threshold conﬁgured by the system administrator

— The migration event occurs on a conﬁgured daily or weekly schedule

Note Use the show cable spectrum-group command to display the current allocation table and

frequency assignments.

RF Topology Example

Following is an example topology for a Cisco uBR7223 with combiner groups designated A through

J. Combiner groups C and E have multiple upstream ports. These should be conﬁgured in a shared

spectrum group. The other upstreams should be conﬁgured in a non-shared spectrum group.

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Cisco MC16S Manual de usuario Pagina 5