Cisco Systems uBR7200 Series Anleitung zur Fehlerbehebung PDF herunterladen (Seite 48)

4-48

Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide

78-5897-01

Chapter 4 Troubleshooting the System

Pinging Unresponsive Cable Modems

Configure PRBS Test Signals

Verify Test Signal Output

To verify the output of a continuous-wave test signal or the output of a PRBS test signal, use a spectrum

analyzer on the downstream channel. The downstream carrier is enabled as a default.

The standard mode of operation is modulated signal output and the interface is active. For PRBS and

continuous wave output, the selected interface will be shut down.

The functioning of the no cable downstream if-output command has not changed. The interface is shut

down.

Pinging Unresponsive Cable Modems

Ping a Cable Modem

Ping DOCSIS is a Cisco patent-pending feature that allows a cable system administrator to quickly

diagnose the health of a channel between the Cisco uBR7200 series universal broadband router and the

cable modem. The technology uses 1/64—the bandwidth of IP ping—and works with cable modems

that don’t have an IP address. This allows cable operators to ping cable modems that are unable to

complete registration, have internal bugs, or that are unresponsive due to a crash.

Information the Ping DOCSIS feature includes a real-time view and plot of requested power

adjustments, as well as a measure of optimal headend reception power. This gives the cable operator the

ability to solicit a configurable number of periodic ranging requests from a cable modem.

To ping a specific cable modem to determine if it is online, use the following command in EXEC mode.

Table 4-30 Instructions to Conﬁgure PRBS Test Signals

Step Command Purpose

# router(config-if)# cable downstream if-output prbs

Generates a PRBS test signal on the downstream

channel. The interface is shut down.

Router(config-if)# no cable downstream if-output

Stops sending test signals.

Note Remember to reenable the

interface to resume normal

operations.

Table 4-31 Instructions to Ping a Cable Modem

Command Purpose

CMTS01# ping docsis

addr

Ping the cable modem with a specific MAC address

or IP address to see if it is online.

1 2 ... 43 44 45 46 47 48 49 50 51 52 53 ... 57 58

Keine Kommentare

Cisco Systems uBR7200 Series Anleitung zur Fehlerbehebung Seite 48