Cisco Broadband Cable Command Reference Guide

Chapter 2 Cisco Cable Modem Termination System Commands
OL-1581-05
cable modulation-profile
Examples The following example shows how to create a mixed modulation profile, using 16-QAM for the short
and long grant bursts and QPSK for the request, initial ranging, and station maintenance bursts. The burst
parameters are set to their default values for each burst type.
Router(config)# cable modulation-profile 8 mix
Router(config)# exit
Router# show cable modulation-profile 8
Mod IUC Type Preamb Diff FEC FEC Scrambl Max Guard Last Scrambl Preamb
length enco T CW seed B time CW offset
BYTES size size size short
8 request qpsk 64 no 0x0 0x10 0x152 0 8 no yes 0
8 initial qpsk 128 no 0x5 0x22 0x152 0 48 no yes 0
8 station qpsk 128 no 0x5 0x22 0x152 0 48 no yes 0
8 short qam 144 no 0x6 0x4B 0x152 6 8 yes yes 0
8 long qam 160 no 0x8 0xDC 0x152 0 8 yes yes 0
Router#
Note The above example shows the default values for the burst parameters. The main differences in the default
values between 16-QAM and QPSK bursts are in the Type and Preamble Length fields.
The following example shows how to define the burst parameters for profile 2 as follows:
The request burst is defined to have 0 fec-tbytes, 16 kbytes 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. The remaining request data, initial, station, short, and long bursts are defined in similar fashion
for profile 2.
Router(config)# cable modulation-profile 2 request 0 16 1 8 qpsk scrambler 152 no-diff 64
fixed uw8
Router(config)# cable modulation-profile 2 reqdata 0 16 1 8 qpsk scrambler 152 no-diff 64
fixed uw8
Router(config)# cable modulation-profile 2 initial 5 34 0 48 qpsk scrambler 152 no-diff
128 fixed uw16
Router(config)# cable modulation-profile 2 station 5 34 0 48 qpsk scrambler 152 no-diff
128 fixed uw16
Router(config)# cable modulation-profile 2 short 6 75 6 8 16qam scrambler 152 no-diff 144
fixed uw8
Router(config)# cable modulation-profile 2 long 8 220 0 8 16qam scrambler 152 no-diff 160
fixed uw8
Note You must create all of the bursts (request, initial, station, short and long) for this modulation profile,
using the modulation profile command. The reqdata burst is optional.
See the show cable modulation-profile command for a description of the output display fields.
Related Commands Command Description
cable upstream modulation-profile Assigns a modulation profile to an interface.
show cable modulation-profile Displays a modulation profile group’s information.
Cisco Broadband Cable Command Reference Guide
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