Chapter 46: Command Line Descriptions
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
1396
Supplemental
Information
(continued)
The second type is pre-defined modulation profiles which provide a shortcut method for a user to easily create modulation profiles
just by specifying the desired channel type and modulation rate. Pre-defined modulation profiles can be assigned to any number
from 3–n to create a new profile. (It is recommended that you do not use 1 or 2; otherwise you will overwrite the defaults). If you
choose a number that is already in use, then the existing modulation profile will be overwritten by the new one.
Each pre-defined modulation profile is defined by a channel type, such as tdma, and a modulation type, such as 16QAM. The pre-
defined profile defines most of the parameters for that modulation and channel type.
Basically, pre-defined modulation profiles allow the user to specify the channel type and the modulation rate for the data IUCs and
the rest of the information for the modulation profile is filled in with recommended values.
The pre-defined modulation profiles are used as a means to define the values of the several parameters needed to configure an
upstream (US) channel. These modulation profiles are each given an ID number. They can be modified or used as a starting point to
create other modulation profiles for upstream.
These recommended values are generic values that should work across a wide variety of plants. Users may want to optimize these
values to the specific needs of their cable plant.
In order to delete an IUC from a modulation profile or the entire modulation profile, use the no option.
Note: If the IUC is provided, then only that IUC is deleted. If the IUC is omitted, then all IUCs for the given modulation profile are
deleted. If an IUC is being used by an upstream, then that IUC will not be deleted. If the user attempts to delete an IUC that does not
exist or a modulation profile that does not contain at least one IUC, then a notice is given indicating that no action was performed.
Parameters
<id>
Identifier. The number of the modulation profile. There is no software-defined limit to the number of possible modulation profiles.
iuc <1-6, 9-11>
Interval Usage Code. The IUC typically has an assigned numeric value. It defines what kind of Information Element (IE) is being sent
from the C4 CMTS to the cable modems:
1 Request This portion of the upstream map interval is used by cable modems to request bandwidth for data transmission. If the
class of the SID associated with the request IE is broadcast, then cable modems must contend with each other for upstream
bandwidth. If the class of the SID associated with the request IE is unicast, then this is an opportunity for a single cable modem to
request additional bandwidth.
2 Request/Data Either data requests or short data messages can be sent in this portion of the upstream map interval. A multicast
SID must be used to indicate the size of the data message that can be sent. This IE is not used by the C4 CMTS map algorithm and as
such changes made to this IE will have no affect on upstream data transmissions.
