Cisco Systems uBR7200 Series manual Managing Cable Modems on the HFC Network

Chapter 4 Troubleshooting the System

Managing Cable Modems on the HFC Network

Tips The SNR estimate for a cable modem installed at a headend should be between 35 dB and 39 dB. Although the exact value displayed will vary from cable modem to cable modem, values collected on the same cable modem from measurement to measurement will be consistent. Maximizing SNR optimizes cable modem reliability and service quality.

Managing Cable Modems on the HFC Network

To manage cable modems connected to the network, perform the following as appropriate:

•Configure Sync Message Interval

•Activate Cable Modem Authentication

•Activate Cable Modem Upstream Address Verification

•Configure Dynamic Contention Algorithms (Cable Insertion Interval, Range, and Data Backoffs)

•Configure the Dynamic Map Advance Algorithm

•Configure Per Modem Filters

•Configure the Maximum Number of Hosts Attached to a Cable Modem

•Configure Cable Modem Registration Timeout

•Clear Cable Modem Reset

•Clear Cable Modem Counters

•Configure Traffic Shaping

•Configure Spectrum Management (without the Cisco MC16S Cable Modem Card)

Caution Cisco recommends using default values for most commands. Default settings are adequate for most systems.

Configure Sync Message Interval

To specify the interval between successive sync message transmissions from the Cisco uBR7200 series, use the following command in cable interface configuration mode.

Table 4-1	Instructions to Configure Sync Message Interval
Command		Purpose
CMTS01(config-if)#cable sync-interval msec		Specify the interval in milliseconds between
		successive sync message transmissions from the
		Cisco uBR7200 series. Valid values are from
		1 to 200 msec. Default = 10 msec.
no cable sync-interval		Return the sync message interval to its default
		value of 10 msec.

Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide

4-2 78-5897-01