The Ideal Headend
Evolution to Carrier Class
WHITE PAPER
Today’s successful cable operators are ramping up their
networks to deliver advanced services—HD video-on-
demand (VOD), tiered high-speed data, voice-over-IP
(VoIP) and commercial services. MSOs are focused on
improving network reliability and customer satisfaction,
and understand the importance of “carrier-class”
infrastructure. In order to reach the highest level of
delivering the extremely reliable services customers
expect, MSOs must begin thinking about the “ideal
headend.”
Path to the ideal headend
In the most basic terms, an ideal headend is the key to
enabling MSOs to grow their system without major
rebuilds each time new services are added. In the past,
these networks were typically designed and built to meet
only the needs of the day. To be successful in today’s
brutally competitive environment, the mindset has to
shift. Cable operators must look five to 10 years into the
future and design a system that can easily accept and
integrate new equipment into the existing network—a
system that can deliver voice, video, data and wireless
services for the quadruple play.
As high-tech hardware, such as VOD servers, is
introduced to the network, connectivity infrastructure
must be designed to “wrap” the new equipment.
Keeping in mind the old cliché that a network is only as
strong as its weakest link, proper network
documentation, a solid foundation of RF and fiber signal

configuration with battery back-up.
Today, most cable headends use some type of hybrid
power—some equipment powered by AC and some
by DC. But telephone companies are almost exclusively
DC powered, so for cable operators to emulate the
carrier-class services of their telecom competitors, they
will need to adapt their power distribution to enable
delivery of additional services. DC power and redundancy
will become critical issues. For instance, the systems that
power the high-speed Internet are extremely power
hungry, drawing up to 70 amps per unit, and there are
very specific requirements for continuously powering
these devices.
Although DC requires more initial cost during installation
and uses more real estate, the improvement to network
reliability cannot be overstated. Capital expenditures
must be weighed against the possibility of higher
operational costs down the road. Truck rolls and
technicians are a large part of operational costs so,
simply put, upping the reliability lowers the number of
service calls required.
Cable MSOs ideal headend—the evolution to ‘carrier class’
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THE CABLE MSO’S IDEAL HEADEND—THE EVOLUTION TO ‘CARRIER-CLASS’
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networks that offer “full suite” services will simply be
unacceptable.
The impact of DC power is immediately apparent if one
considers several attributes:
• DC power is conditioned power, enabling equipment
to run more smoothly and efficiently
• Systems can be configured for longer standby at
hubs or nodes
• Since equipment is direct-wired rather than plugged
in, connections are unlikely to disconnect
• Each piece of equipment can now be
individually fused
• There is A to B power redundancy to each individual
piece of equipment
• A DC power plant is easier to monitor
• Cable management, a huge consideration in FTTP
networks, is more cleanly managed
Power is never a no-brainer, especially when it comes to
doing the “heavy lifting” for the network. If the power
fails, the network fails. If the network fails, customers
look elsewhere for more reliable service. In the ideal
headend, the right power scheme is employed to offer
uninterruptible delivery of advanced IP services.
Circuit-switched telephony
In typical cable system, circuit-switched telephony is
accomplished by headend equipment that “talks” to a
telephone switch at a telephone company’s central office.
However, with the advent of IP telephony, those systems
are rapidly migrating to some form of packetized
transport. Telephony is exiting the days of circuit switching

Fiber Frame
Softswitch
IP PSTN SS7
Router
VMX
Trunking Media
Gateway
CMTS
O to E Converter
CALEA Mediation
Announce-
ment
CMTS CMTS
Video
Voice
Packet Voice
Data
PowerWorx
DC DC
DSX-1 DSX-3
RF Worx
True N et
PowerWorx
DC DC
PowerWorx
DC DC
Legacy
HDT
RF Worx RF Worx
A/V Patching

cable-management device. Measures should be
taken to avoid damaging, pulling, stretching,
crushing or pinching existing fibers in the vicinity
of the work area.
Another key is bend-radius protection. As fiber is
bent, the radius can become too small and allows
light to escape the core and enter the cladding.
The result is insertion loss in the fiber or a
macrobend that decreases the signal or, in
extreme cases, causes complete signal loss and
data-transfer failures.
Finally, an integrated slack-storage strategy or
system is necessary. Each fiber, due to the high
tolerance needed, is normally terminated in the
factory to eliminate the high costs involved with
field terminations. This typically results in fixed
cable lengths and patch cords. Once the
technician arrives at the job site to make a
connection, the fiber cable or patch cord may be
longer than what is actually required.
Therefore, a system must allow the proper storage
of the slack—the difference in length between
what is actually needed to physically make the
connection and what the technician actually has
to work with.
Data center connectivity
Historically, cable providers only had a handful of
data cables in the headend, mostly connecting
computers to the network. But today, data is a
large part of the headend, especially to provide

and reliable for delivering triple-play bundles will
enable the delivery of carrier-class services that
customers expect and demand. ADC’s time-tested
products and professional services help enable
cable operators to design and build the reliable and
flexible multivendor headends, and provide firm
footing on which to compete in the triple- and
quadruple-play services space.