Cisco Systems uBR7200 Verifying the Upstream Scrambler, MC-552, Troubleshooting Tips, Command

Configuring Headend Broadband Access Router Features

Configuring the Upstream Cable Interface

Caution The upstream scrambler must be activated for normal operation. Disabling it can result in corrupted packets. Disable it only for prototype modems that do not support scrambler.

To activate the upstream scrambler after it has been disabled, use the following command in cable interface configuration mode:

Command	Purpose
CMTS01(config-if)#cable upstream usport scrambler	Enables the scrambler. This is the default.

Verifying the Upstream Scrambler

To verify whether or not the upstream scrambler is activated, enter the more system:running-configcommand and look for the cable interface configuration information. The following is an excerpt from the more system:running-configcommand output:

CMTS01# more system:running-config

Building configuration...

Current configuration:

!

interface Cable6/0

ip address 1.1.1.1 255.255.255.0 no keepalive

cable insertion-interval 150000

cable downstream	annex B
cable downstream	modulation 64qam
cable downstream	interleave-depth 32
cable downstream	symbol-rate 5056941
cable upstream 0	frequency 15008000
cable upstream 0	fec
cable upstream 0	scrambler

no cable upstream 0 shutdown

Troubleshooting Tips

To troubleshoot the configuration, perform the following tasks:

•Make sure the cable connections are not loose or disconnected.

•Make sure the Cisco cable modem card is firmly seated in its chassis slot and the captive installation screws are tight.

•Make sure you entered the correct slot and port numbers when you typed the command.

•Make sure you entered the correct upstream port number:

–On the MC16C cable modem card, this can be u0 to u5.

–On the MC14C cable modem card, this can be u0 to u3.

–On the MC12C cable modem card, this can be u0 or u1.

–On the MC11C cable modem card, this can be u0 only.

Cisco IOS Multiservice Applications Configuration Guide

MC-552