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There is currently a mismatch between the capacities
of internal premise networks, the public network’s metropolitan
core, and the “last-mile” infrastructure that connects the two. |
Changes in technology, regulation, and competitive market
structures are creating opportunities for integrating voice, data and video
(VDV) services into enterprise networks. From a cable-management
perspective, however, installing the service lines for these capabilities is
congesting central network wiring closets.
Congestion happens because a distinct network interface device is required
at each point of presence (PoP) handoff from each service provider. Not only
does this consume more space in already-tight physical quarters, it makes
the routing of wire lines to internal network devices more chaotic.
This wiring closet chaos will intensify as competition among service
providers increases and broadband delivery technologies diversify. Telephone
companies, multiple-service cable operators and colocated broadband
providers are looking at fiber to the premise (FTTx), Ethernet in the first
mile (EFM), third-generation data-over-cable-service (DOCSIS 3.0), xDSL and
other DSx-based technologies that will require new types of interfaces at
the handoff point.
The clutter in most wiring closets is the result of adding network services
without a master plan for managing how the incoming wire lines physically
integrate with the existing configuration.
One solution to streamlining today’s network handoffs–and future proofing
tomorrow’s–is modular “mix-and-match” media wire line management, a single
physical point of termination that can accept any combination of wire line
media types. Modular connectivity is a scalable approach that can bring
organized and efficient use of space to the wiring closet, enable rapid
workarounds and new deployments, and enhance interconnect reliability on
both sides of the handoff.
There is currently a mismatch between the capacities of internal premise
networks, the public network’s metropolitan core, and the “last-mile”
infrastructure that connects the two. The public network and most access
networks support tens or hundreds of gigabits-per-second data rates, while
the last-mile interface runs at sub-megabit or kilobit rates. As a result,
virtually all of the efforts to increase bandwidth will take place in the
last mile in the foreseeable future.
The viable candidates right now for broadband last-mile media are fiber to
the premise, terminated via SC physical contact connectors and adapters,
Category 6 unshielded twisted pair (UTP) terminated via RJ-45 connectors,
and
RG-6 coax terminated into either carrier-class BNC or three-piece F
connectors.
There are three key building blocks in the mix-and-match media management
approach. The first is the universal subpanel–the mounting mechanism that
enables modules for multiple connector types to be colocated. This panel is
roughly 4 inches by 1 inch in size, with a pair of installation grommets for
rapid attachment/assembly.
The second building block is the interchangeable module–the heart of the
mix-and-match capability. Several types of these modules are available. The
most flexible is the keystone type, which allows multiple industry-standard
connectors to be mixed in a single subpanel in a pass-through configuration.
Currently available keystone modules include 50 ohm BNC, 75 ohm BNC, 75 ohm
F-type, RJ-45, RCA and SC (fiber optic).
A second type of interchangeable module is the BNC pass-through/monitoring
jack, available for premise DS-3 and digital video connectivity. These
pass-through jack modules have test ports that enable quality-of-service
checks without service disruption, and enable quick determination of which
side of the handoff is responsible for performance problems. Variations
include gas-tube protection features that are designed for outside plant
installations.
The third building block is the distribution panel. There are multiple
options for containing the modular subpanels, depending on the size of the
wiring closet. The most flexible and expandable distribution panel is the
rackmount system, consisting of 19”- or 23”-wide 1RU-high panels that hold
three or four loaded subpanels. The rack system is scalable and capable of
organizing inbound wire lines for large building or campus wiring closets.
For smaller wiring closets, one solution is the double-lockable enclosure.
These give the service provider and the network infrastructure manager
secured access to their respective sides of the handoff. Available models
accommodate four subpanels, allowing up to 20 keystone wire line
pass-through interconnects. Wall-mounted L-brackets, holding up to three
subpanels that allow up to 15 pass-through interconnects, are also
available.
In today’s rapidly evolving VDV environment, the ability to accommodate new
service types and incoming wire lines without having to rip and replace
single-purpose PoP equipment, along with the rerouting and termination of
inside wire lines, is more attractive than ever before. Consider the case of
switching from traditional voice service provided by the local phone company
to voice over Internet protocol (VoIP). With a rack-mounted modular
connectivity system in place, all the installer needs is to add the
appropriate interchangeable connectivity module, terminate the inbound cable
with the appropriate connector (preferably a high-reliability carrier-class
F or BNC with gold-plated center pin), and install the connector to the
provider side of the handoff wire line.
Depending on the distribution/routing equipment to be installed and the
level of monitoring capability desired, modules are available for either a
straight pass-through with line-monitoring capability on both the transmit
and receive channels on one side of the handoff, or a pass-through module
that enables monitoring only on one side of a PoP network access test point.
If the initial choice of IP service to support a VoIP installation does not
work out and the new provider is bringing fiber to the premise, all that is
necessary is to switch out the previous interchangeable module and install
one appropriate to terminate the new incoming wire line. In this case, an SC
adapter module establishes the handoff, and the internal routing is a simple
straight-line connection to the optical network element. This same
simplicity and ease of accepting new service will apply to connecting any
other high data-rate wire line.
Clay Feustel is senior applications engineer and Dale Reed is vice president
of sales and marketing for Trompeter, Mesa, Ariz.
For more information:
www.rsleads.com/609cn-256
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