Chapter 14: Cable-side Configuration
STANDARD Revision 1.0 C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved. 415
configure cable fiber-node FN4 cable-downstream 12/12
configure cable fiber-node FN4 cable-downstream 12/13
configure cable fiber-node FN4 cable-downstream 12/14
configure cable fiber-node FN4 cable-downstream 12/15
It is not necessary to use a separate command for each channel that you assign to a fiber node. You can add several
channels on one command line, shown as follows:
configure cable fiber-node FN4 cable-downstream 12/12-15
configure cable fiber-node FN5 cable-downstream 12/9,11
Cable Modem Timing, Supervision, and Messaging
Before it can initialize, each cable modem (of any DOCSIS version) requires a downstream channel that carries the
following:
SYNC messages (for system timing)
Supervision information for at least one upstream channel
In addition, a DOCSIS 3.0 CM requires the following, in order to register with multiple receive channel mode:
Detailed (lengthy) MDD messages
MAP messages and UCD messages for all upstream channels which will be used in ambiguity resolution
Primary-Capable Downstream Channel
A downstream channel that provides all of the aforementioned timing, supervision, and messaging information is known as
a primary-capable downstream channel. Such a downstream channel is capable of becoming a cable modem’s single
primary downstream channel which it will use to derive all timing for system access in the upstream direction.
Because primary-capable downstream channels are the only downstream channels that carry timing information, they are
also the only downstream channels that pre-3.0 DOCSIS cable modems can use for service. Therefore, primary-capable
downstream channels can be expected to carry slightly more overhead traffic than non-primary-capable downstream
channels.
Note: The MSO should ensure that it has configured enough primary-capable channels to support legacy CMs.
Each MD-DS-SG must contain at least one primary-capable downstream channel so that CMs can register and operate. The
MSO may also wish to configure more than one DS to be primary-capable if there is a large number of pre-3.0 CMs.
To Next Page
Loading...