8 Mbps 55.6 Mbps
DOCSIS 3.0 N*30.7 Mbps
(N = 4 ??“ 13)
M*38.8 Mbps
(M = 4 ??“ 100+)
M*55.6 Mbps
(M = 4 ??“ 80+)
TABLE 6.1 Maximum Data Rate for Each of the DOCSIS Versions
Note: In the DOCSIS 3.0 specification, the multiplication factors N and M are equipment dependent, with the
minimum for each being four and the maximums limited by the spectrum allocations.
150 Chapter 6
Physical Plant The modern physical cable network is built upon a hybrid fiber-coax
(HFC) architecture. At its simplest, this architecture is composed of optical fiber that
connects the cable operator??™s ???head-end??? equipment to devices in the field (fiber nodes)
that convert the signals from optical to electrical and vice-versa. Coaxial cable (coax)
then connects the fiber nodes to the end devices located at the customers??™ premises.
Fiber nodes are typically not intelligent devices, in that they do not demodulate or
process the signals that pass through them. They are physical layer devices that simply
convert the signal from one form to the other.
The network topology is the ???tree and branch??? type, with the head-end at the base
of the tree and the end devices at the leaves.
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