Cisco Systems uBR7200 Setting the Downstream Channel ID, Verifying the Downstream Channel ID

Configuring Headend Broadband Access Router Features

Configuring the Downstream Cable Interface

Setting the Downstream Channel ID

To assign a numeric channel ID to the downstream port on the Cisco cable modem card, use the following command in cable interface configuration mode:

Command	Purpose
CMTS01(config-if)#cable downstream channel-id id	Specifies the downstream channel ID. Acceptable range is
	0 to 255.

Verifying the Downstream Channel ID

To verify the downstream channel ID, enter the show controllers cable command for the downstream port you have just configured:

CMTS01# show controllers cable 6/0 downstream

Cable6/0 Downstream is up

Frequency=96000000, Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 Msps

FEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4

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 the downstream carrier is active by entering the cable downstream if-outputcommand.

Setting the Downstream MPEG Framing Format (Annex B)

The Moving Pictures Experts Group (MPEG) framing format must be compatible with your local standards and specifications for downstream MPEG framing. Annex B is the DOCSIS MPEG framing format standard for North America; Annex A is the European standard.

In Cisco IOS Release 12.1, only the Annex B MPEG framing format is supported.

Note The cable modem card downstream ports and the cable modems on the HFC network connected through these ports must be set to the same MPEG framing format.

To set the downstream MPEG framing format, use the following command in cable interface configuration mode:

Command	Purpose
CMTS01(config-if)#cable downstream annex B	Sets the downstream MPEG framing format.

Cisco IOS Multiservice Applications Configuration Guide

MC-538