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Cisco Broadband Cable Command Reference Guide
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Chapter 2 Cisco CMTS Configuration Commands
cable modulation-profile
Defaults
Modulation profile 1 is defined as a
qpsk
Time Division Multiple Access (TDMA) profile.
In Cisco IOS Release 12.2(15)CX, Release 12.2(15)BC2 and later releases, additional modulation
profiles are defined as the default mixed TDMA/A-TDMA profile and the default Advanced TDMA (A-
TDMA) profile. The modulation profile numbers for these default values are 1, 41, 101, 121, 201, 221,
or 241, depending on the cable interface line cards being used (see
Table 2-5 on page 2-171
).
Note
The default profiles (1, 41, 101, 121, 201, 221, or 241) cannot be deleted. Using the
no cable
modulation-profile
command on these particular profiles resets them to their original, default values.
Command Modes
Global configuration
Command History
seed
(Required if
scrambler
option used) Scrambler seed in hexadecimal
format. Valid values are from 0000 to 7FFF.
diff
Enable or disable differential encoding. Valid entries are
diff
and
no-diff
.
Note
In DOCSIS 2.0 mode, differential encoding cannot be enabled for
the 8-QAM, 32-QAM, and 64-QAM modulations.
pre-len
Preamble length in bits. Valid values are from 2 to 512.
last-cw
Handling of FEC for last code word. Valid entries are
fixed
for fixed code-
word length and
shortened
for shortened last code word.
uw-len
Upstream unique word length. Enter
uw8
for 8-bit unique code words or
uw16
for 16-bit unique code words.
Release
Modification
11.3 NA
This command was introduced.
12.0(7)XR2
This command was supported.
12.0(6)SC and 12.1(3a)EC1
The
mix
,
qpsk
, and
qam-16
options were added.
12.2(8)BC2
Support was added for the Cisco uBR10012 router.
12.2(11)CY
Support was added for the Cisco uBR-MC5X20S cable interface line
card. This includes creating default modulation profile 21 for the
card.
12.2(15)CX
Support was added for the Cisco uBR-MC16U/X and
Cisco uBR-MC28U/X cable interface line card, including support for
DOCSIS 2.0 A-TDMA and mixed modulation profiles on this card.
The
robust
predefined modulation profiles were also added for all
modes of operation. The robust profiles use a longer preamble to
provide better handling of noise on the upstream, but they also
consume more bandwidth at the PHY layer than the other profiles.
12.2(15)BC2
Support was added for the Cisco uBR-MC5X20S/U cable interface
line cards, including support for DOCSIS 2.0 A-TDMA and mixed
modulation profiles. Support for the IUC-11 burst profile (Advanced
UGS,
a-ugs
) was also added for mixed TDMA/A-TDMA modulation
profiles.