Arris C4C - Сonfigure Interface Cable-Downstream Cable Modulation

Chapter 46: Command Line Descriptions
STANDARD Revision 1.0 C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved. 1481
configure interface cable-downstream * cable modulation
Purpose
Downstream modulation defines the speed in bits per second at which data travels downstream to the subscriber’s cable modem.
Default Access Level
15
Command Syntax
configure interface cable-downstream <slot/port> cable modulation <64qam | 256qam>
Supplemental
Information
A symbol is the basic unit of modulation. QPSK encodes 2 bits per symbol. 16-QAM encodes 4 bits per symbol, 64-QAM encodes 6
bits per symbol, and 256-QAM encodes 8 bits per symbol.
Setting a downstream modulation format of 256-QAM requires approximately a 6 dB higher signal-to-noise ratio (SNR) than 64-QAM
at the subscriber’s cable modem. If your network is marginal or unreliable at 256-QAM, use the 64-QAM format instead.
Parameters
<slot>
The chassis slot in which the targeted downstream Cable Access Module resides. Valid range for the C4 CMTS is 0-15; valid range for
the C4c CMTS is 10-15.
<port>
The downstream port.
<64qam | 256qam>
64qam modulation rate is 6 bits per downstream symbol
256qam modulation rate is 8 bits per downstream symbol
Default is 256 QAM