Cisco Broadband Cable Command Reference Guide

Chapter 2 Cisco Cable Modem Termination System Commands
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cable downstream if-output
Note Generating a PRBS or continuous-wave test signal or shutting down the interface automatically stops the
modulated carrier data signal and disconnects all CMs on that downstream. These commands should not
be used on a live network except as part of troubleshooting major network problems.
Examples The following example shows how to enable downstream port 0 on a cable interface:
router# configure terminal
router# interface c6/0
router(config-if)# cable downstream if-output
router# (config-if)#
The following example shows a PRBS test signal being generated on a downstream for a period of time.
The downstream is then shut down so that the test engineer can verify that no signal is being sent on the
downstream. After the tests have been run, the downstream is reactivated for normal modulated data use:
router# configure terminal
router# interface c6/0
router(config-if)# cable downstream if-output prbs
(the signals are verified by a spectrum analyzer...)
router#(config-if)# no cable downstream if-output
(the downstream is checked to verify no signals are being sent on it...)
router#(config-if)# cable downstream if-output
router#(config-if)# exit
router#(config)#
Cisco Broadband Cable Command Reference Guide
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