Cisco Systems uBR7200 manual MC-581, Command, Purpose

Configuring Headend Broadband Access Router Features

Configuring Cable Profiles

The following modulation profile values can be changed:

•Interval usage code (iuc)—Valid values are initial, long, reqdata, request, short, and station.

•Fec-tbytes—The number of bytes that can be corrected per FEC codeword. Valid range is 0 to 10 bytes, where 0 means no FEC.

•Fec-len—FEC codeword length. Valid range is 8 to 254 bits.

•Burst-len—Maximum burst length in bytes. A value of 0 means no limit on burst length.

•Guard-t—Guard time in symbols. This is the time between successive bursts.

•Mod—Modulation. Valid values are 16qam and qpsk.

•Scrambler—Enable or disable scrambler. Valid values are scrambler and no-scrambler.

•Seed—Scrambler seed in hexadecimal format. Valid range is 0x0000 to 0x7FFF.

•Diff—Enable or disable differential encoding. Valid values are diff and no-diff.

•Pre-len—Preamble length in bits. Valid range is 2 to 128 bits.

•Last-cw—Handling of FEC for last codeword. Valid values are fixed for fixed codeword length, and shortened for shortened last code word.

•Uw-len—Upstream unique word length. Enter uw8 for 8-bit unique words or uw16 for 16-bit unique code words.

To create or change a cable modulation profile, use the following command in global configuration mode:

Command	Purpose
CMTS01(config)# cable modulation-profile profile iuc	Creates a new cable modulation profile with a profile
fec-tbytes fec-len burst-len guard-t mod scrambler seed	number of profile, or modifies the existing profile having
diff pre-len last-cw uw-len	the number profile.

In the following example, the request burst for cable modulation profile 2 is defined to have 0 fec-tbytes, 16 KB fec-len, a burst-len of 1, a guard time of 8, a mod value of qpsk, scrambler enabled with a seed value of 152, differential encoding disabled, a preamble length of 64 bits, a fixed code-word length, and 8-bit unique words for upstream unique word length.

CMTS01(config)# cable modulation-profile 2 request 0 16 1 8 qpsk scrambler 152 no-diff 64 fixed uw8

To remove a cable modulation profile, use the no cable modulation-profileprofile command in global configuration mode. You can use this command to remove all modulation profiles except for modulation profile 1. Entering the no cable modulation-profile 1 command sets all of the parameters in profile 1 to the default values.

Cisco IOS Multiservice Applications Configuration Guide

MC-581