Chapter 14: Cable-side Configuration
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
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MAC Domains
The MAC domain is a logical subcomponent of the C4/c CMTS that provides data forwarding services to a set of
downstream and upstream channels. In DOCSIS, the MAC domain is the set of CMs that use a common set of upstream and
downstream channels (at least 1 of each) linked together through a MAC forwarding entity of the C4/c CMTS.
A C4/c CMTS can support multiple MAC domains; however, each downstream and each upstream channel of the C4/c
CMTS can belong to only one MAC domain.
DOCSIS Functions
The concept of a MAC domain has been formalized in DOCSIS 3.0 to be an, "C4/c CMTS subcomponent object responsible
for all DOCSIS functions on a set of Downstream Channels and Upstream Channels."
These DOCSIS functions include:
DOCSIS downstream packet data transmission services provided to an C4/c CMTS forwarder including:
Service flow classification
Subscriber management filtering
Packet scheduling among one or more downstream channels to a CM
Downstream channel bonding
Downstream load balancing.
DOCSIS upstream packet data reception services provided to cable modems including:
Generation and distribution of bandwidth allocation messages (MAPs) and upstream channel descriptors (UCDs)
for each upstream channel of the MAC domain associated with the downstream channels of the MAC domain. This
is known as upstream supervision in the C4/c CMTS.
Cable modem ranging
Upstream channel bonding
Upstream load balancing
CM Event reporting.
DOCSIS MAC Management message exchanges with CMs
Before a chassis can achieve DOCSIS operation, the MAC domain itself must be provisioned, including: