Chapter 2: C4/C4c CMTS Features
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
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Annex A only. The C4 CMTS will support four (4) channels at 64 QAM and four (4) channels at 256 QAM on each of the four
(4) F-connector outputs of the XD-CAM. The four (4) 64 QAM channels on each F-connector may be set at a power level 6
dB below that of the 256 QAM channels. All the channels on the F-connector can be in the same MAC domain and could be
channel-bonded together.
Intelligent RCS Assignment/Balancing Control provides the capability such that automatic intelligent assignment of the
Receive Channel Set (RCS) used by a modem results in the assignment of the modem to the least loaded downstream
channels that meet the required service flow attributes at registration.
DSCP Marking for DHCP Packets provides the ability to mark the TOS byte or DSCP for DHCP and DHCPv6 packets leaving
the C4 CMTS after being processed by the DHCP relay agent. DHCP renew packets that bypass the relay agent will not be
marked.
PCMM IPv4/IPv6 Classifiers and gates ECN Support (MM-N-13.0697-1) provides support so that a single PCMM gate for
an upstream or a downstream flow can simultaneously use both an IPv4 and an IPv6 classifier.
DSCP Marking for Downstream Subscriber Traffic The CMTS currently can mark the DSCP for upstream subscriber traffic
but not for downstream. This new feature will extend this capability to the downstream in order to create a greater level
of control over the prioritization of traffic.
RADIUS Password Challenge will support a Password Challenge function for RADIUS Authentication by adding support for
the Access Challenge message.
Support for Multi-Tuner Cable Modems provides support for multi-tuner CMs without resorting to static RCCs which can
be difficult to configure, such as:
Two tuners per modem
Four channels per tuner
Other permutations of numbers of tuners and channels may be supported (i.e. M tuners, N channels per tuner where
M/N is an integer and M>1).
Bonding of Eight Upstream Channels (24U CAM) supports bonding of eight (8) upstream channels with the 24U CAM
(Note: bonding of five, six, and seven upstream channels will also be supported. The current support for bonding of
channels of varying widths or modulation profiles is maintained.
Improved Partial Service supports the capability to recover any upstream channels that were placed into an impaired state
when the channel was reported as impaired via the REG-ACK or DBC-RSP messaging mechanism. This feature is disabled by
default. When enabled, the C4 CMTS will continue to send unicast ranging opportunities for any upstream channels that
