Cisco Broadband Cable Command Reference Guide

frequency
frequency
Syntax Description
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Cisco Broadband Cable Command Reference Guide
Chapter 2 Cisco Cable Modem Termination System Commands
To create a DOCSIS configuration file that specifies the center frequency for downstream channel for a
CM, use the frequency command in cable config-file configuration mode. To remove the downstream
channel frequency, use the no form of this command.
frequency freq
no frequency freq
Defaults The CM defaults to scanning the downstream for available downstream frequencies.
Command Modes Cable config-file configuration
Command History
freq Specifies the downstream frequency in multiples of 62500 Hz. Valid range
is 88 to 860 MHz.
Release Modification
12.1(2)EC1 This command was introduced.
12.2(4)BC1 Support was added to the Release 12.2 BC train.
Usage Guidelines This command typically is not used because the CM during its registration process scans the downstream
frequency spectrum for an available downstream channel. If the CM finds a channel and can successfully
lock on it, the CM uses that channel until the CMTS instructs otherwise.
However, there could be situations in which you want to specify that a CM should use a specific
downstream center frequency. In these situations, use the frequency command to require the CM to use
that frequency. For example, specifying a particular center frequency can improve the ability of the
network to recover when a CM loses downstream lock, because it retries only the one frequency instead
of scanning the entire downstream spectrum.
Note The frequency specified by the configuration file must match the output frequency of the upconverter;
otherwise, the CM cycles offline each time the configuration file is received.
Examples The following example shows how to specify the downstream center frequency for a DOCSIS
configuration file:
router(config)# cable config-file fixedfreq.cm
router(config-file)# frequency 453000000
router(config)# exit
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