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
Benefits
Note The Dynamic Upstream Modulation feature was introduced in Cisco IOS
Release 12.1(3a)EC1. The above enhancements to this feature exist only in Cisco IOS
Release 12.2(8)BC2 and later 12.2 BC releases; they are not supported in any Cisco IOS
12.1 EC Release.
• When using a Cisco uBR-MC16S line card on a Cisco CMTS router running Cisco IOS Release
12.2(8)BC2 and later 12.2 BC releases, the spectrum management hardware uses the real-time CNR
readings from the DSPs onboard the Cisco uBR-MC16S line card instead of the signal-to-noise ratio
(SNR) values from the Broadcom 3137 chip to determine the signal quality of the upstream channel.
The CNR value is a more accurate description of noise conditions on the upstream.
• Provides an SNMP interface so that a network management workstation or other graphical tool can
obtain spectrum information for either a particular cable modem or for an entire upstream. The
frequency resolution can be as fine as 12 KHz.
Note The CISCO-CABLE-SPECTRUM MIB has been enhanced to provide this support.
• Supports the DOCSIS Cable Modem Test Analyzer (DCMTA) from Acterna. The DCMTA software
provides spectrum analyzer capability for an individual upstream port or an individual cable modem.
Spectrum data is extracted from the Cisco uBR-MC16S cable interface line card using SNMP,
allowing for live troubleshooting of an upstream port or individual cable modem. The DCMTA
software supports simultaneous client access to a single or multiple CMTS, upstreams, or cable
modems.
Note To contact Acterna about the DCMTA software, call 1-800-638-2049 or [phone],
or visit http://www.acterna.com.
Benefits
The spectrum management features provided on the Cisco CMTS router platforms provide several key
system benefits:
• Improves response time to ingress noise impairments that appear in the upstream return path.
• Boosts the percentage of modems online.
• Mitigates the impact of ingress to subscriber services.
• Saves time and effort by MSO operations staff when troubleshooting minor plant outages.
• Increases cable plant reliability.
• Maximizes spectrum utilization.
Table 3-3 summarizes the specific benefits of the Guided and Scheduled spectrum management features
that are supported for all Cisco CMTS router platforms.