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Cisco Broadband Local Integrated Services Solution Troubleshooting Guide
OL-5169-01
Chapter 7 Troubleshooting the CMTS
Troubleshooting the Cisco uBR7246VXR
The following example confirms that the cable modem at 0050.7366.2223 is connected to the network
and is operational:
# ping docsis 0050.7366.2223
Queueing 5 MAC-layer station maintenance intervals, timeout is 25 msec:
!!!!!
Success rate is 100 percent (5/5)
Following are the keys used for the ping response messages:
Tips If you are having trouble, make sure you are using a valid MAC address for the cable modem you
want to ping.
Setting Downstream Test Signals
This section provides configuration commands that allow you to create downstream test signals. Both
Pseudo Random Bit Stream (PRBS) and unmodulated carrier test signals are supported.
A PRBS test signal is a random data pattern that has been modulated to look like a real data stream. An
unmodulated test signal is a continuous sine wave that looks like a carrier wave on the downstream
transmission.
Generating Unmodulated Test Signals
To generate unmodulated test signals, perform the steps in Table 7-5 in the configure interface mode.
f The ping message failed.
. The ping message timed out without getting a response.
! The ping message was successfully sent and a reply is received.
Table 7-5 Procedure to Generate Unmodulated Test Signals
Step Command Description
1 Router(config-if)#
cable downstream if-output continuous-wave
Generates an unmodulated
continuous-wave signal on the downstream
channel. The interface is shut down.
2 Router(config-if)#
no cable downstream if-output
Stops sending test signals.
Note Remember to re-enable the
interface to resume normal
operations.
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