Modular Cmts - Cisco WCM300 - Channel Bonded Cable Modem Implementation Manual

Modular CMTS

Modular CMTS

Figure 3-3 Cisco Cable Wideband M-CMTS Architecture
uBR10012
WCMTS
Regional
WAN
cable
WAN
headend
Wideband SIP
Wideband SPA GE
MC5X20
cable interface
line card
Cisco Cable Wideband Solution Design and Implementation Guide, Release 1.0
3-4
Figure 3-2 Wideband Channels and Primary Downstream Channels on a Fiber Node
WB1
WB2
A WCM on the fiber node can come online on WB1/PDC1, on WB1/PDC2, or on WB2/PDC1. On the
CMTS, WB1, WB2, PDC1, and PDC2 all are members of the same virtual interface bundle.
For information on configuring virtual bundle interfaces, see the Cisco uBR10012 Universal Broadband
Router SIP and SPA Software Configuration Guide.
The Cisco Cable Wideband Solution, Release 1.0, uses of a variant of the modular CMTS (M-CMTS)
architecture. With a modular CMTS architecture, the downstream PHY (physical layer) of the CMTS is
located in a separate network element: the edge QAM device. CableLabs defines the M-CMTS
architecture, which is one of the DOCSIS specifications. The M-CMTS architecture and wideband
(DOCSIS 3.0) channel bonding are closely related technology pieces.
The CableLabs specification for the M-CMTS architecture defines changes to the edge QAM device that
require it to be both DOCSIS-aware and synchronized to the DOCSIS subsystem. The Cisco Cable
Wideband Solution, Release 1.0, implementation of the M-CMTS architecture does not place these
requirements on the edge QAM device.
For a single wideband channel,
Cable Wideband Solution, Release 1.0. In this example, two downstream RF channels are bonded
together into one wideband channel. The Gigabit Ethernet (GE) switch is optional.
Downstream
wideband
channel
Traditional DOCSIS downstream channel
for MAC management and signaling messages
Traditional DOCSIS upstream channel for
In the M-CMTS architecture used for the Cisco Cable Wideband Solution, Release 1.0, traditional
CMTS functionality is divided into two network elements as follows:
PDC1
PDC2
NB1 NB2
Figure 3-3 shows the M-CMTS architecture as it is used in the Cisco
Optional
Edge QAM
GE
device
switch
return data traffic and signaling
Chapter 3 Cisco Cable Wideband Architecture
Downstream
wideband channel
RF
Wideband
cable modem
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