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
Feature Overview
The cable interface does not operate until you either create and configure a spectrum group or set a fixed
upstream frequency. Configuring a spectrum group disables the fixed upstream frequency setting. From
the interface configuration prompt, an interface is assigned membership in a spectrum group. From the
interface point of view, the spectrum group also represents the set of upstreams connected to the same
group of fiber nodes. The spectrum manager software in Cisco routers determines if upstream
frequencies need to be managed together.
The upstream ports use a spectrum group to implement a frequency hopping technique. The types of
frequency hopping techniques are guided, time-scheduled, and a combined guided and time-scheduled.
See the “Frequency Hopping Capabilities” section on page 3-10 for more information on the types of
frequency hopping techniques.
Note When each upstream port has its own RF domain, the group is called a nonshared spectrum group. When
multiple upstream ports share the same RF domain, the group is called a shared spectrum group.
Guidelines for Spectrum Management
In general, 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.
• When multiple upstream ports are combined to provide increased bandwidth, care should be taken
to prevent overlapping frequency bands.
Phases of Spectrum Management
The CMTS provides at least three phases or periods of spectrum management when different features or
enhanced features have been added in different IOS releases:
• Guided and Scheduled spectrum management—Uses Cisco uBR-MC11C, Cisco uBR-MC12C,
Cisco uBR-MC14C, Cisco uBR-MC16C, and Cisco uBR-MC28C cable interface line cards.
• Intelligent spectrum management using the Cisco MC16S cable interface line card—Based on the
Cisco uBR-MC16C cable interface line card plus a spectrum management daughter card.
• Advanced spectrum management—Uses the Cisco uBR-MC16S cable interface line card and
daughter card, an upgrade that provides additional features.
Note Unless otherwise indicated, all references to Cisco cable interface line cards apply to both the
Cisco uBR7200 series versions and the Cisco uBR10012 versions.
Table 3-1 summarizes the spectrum management phases.