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SOLUTIONS FOR PREMISES AND CAMPUS
JUNE 2010 COMMUNICATION SYSTEMS WORLDWIDE
CELEBRATING
100 years PAGE 2
INSTALLATION PAGE 11
Putting optical
theory into practice
DESIGN PAGE 5
Connecting the
collocated facility
w w w.c ablingins t all.c o m
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:: EDITORIAL ::
on cablinginstall.com
A century in the making
Long-time readers of Cabling premises communications systems are
Installation & Maintenance may intricate and complex, to put it mildly.
DESIGN/INSTALL/TEST
remember that a few of our issues over The magazine that could not have Free reference guide to
cabling installation available
the years have fallen into the category been conceived in 1910 is, at least I like
of “commemorative anniversary.” to think, a worthwhile use of its read-
NETWORK CABLE
Established in 1993, ers’ time and an information source
Category 6A deployments
this magazine has taken that helps cabling-industry profession- in the Middle East
the look-back/look-ahead als gain intelligence about the trade.
approach to our 5-, 10-, The “Penn” in PennWell comes from NETWORK PROTOCOLS
and 15-year anniversary Pennsylvania, where the company Optical patch cord paves
issues. This month we’ve originated. The “Well” refers to oil the way to 100G
used our front cover not wells. Incorporated as the Petroleum
to recognize any particu- Publishing Company, my employer’s WIRELESS
lar milestone of the mag- deepest roots are in the oil and gas Multi-gig wireless
azine itself, but rather to acknowledge industries. As I write this column in specification published
the 100th birthday of PennWell, the May 2010 the BP oil spill continues to
DATA CENTER
company that owns this title. belch from the ocean floor, and also
International standard
Telephone deregulation, which continues to dominate headlines in
for data center facilities
took effect in the 1980s, was really every form of media, from newscasts to management
the watershed event that eventually newspapers and across the Web.
brought this publication to fruition. While retelling the state of commu- CABLING STANDARDS
When our parent company nications in 1910 earlier, I was tempted Standards reference
PennWell was born 100 years ago to include a sarcastic comment like, guide focuses on 568-C
there was no concept of an informa- “A lot can happen in 100 years.” But
tion source for building owners who in light of the current state of affairs CONNECTIVITY
were challenged to operate the grow- off the coast of Louisiana, it’s more Cat 6A plug assembles
ing and changing cabling systems appropriate to remind myself that a lot
in one minute
within their properties. As the image can happen in one second. This pub-
BLOG
on the left side of this month’s cover lication, its parent company, and I bet
FBI points to VoIP as
depicts, communications systems most of you reading this column have
element of online scheme
within buildings were, well, differ- learned that lesson, perhaps the hard
ent from what they are now. American way. In this brief space where I recog-
Visit cablinginstall.com for
Telephone and Telegraph was a mere nize a company’s 100th birthday, I’ll
these and other news stories.
25 years old then. Alexander Graham ask each of you to make every second
Bell’s patent on the telephone was still of every day of all your years, count.
in effect. PATRICK McLAUGHLIN
Today, as the image on the right Chief Editor
side of this month’s cover illustrates, patrick@pennwell.com
2 JUNE 2010 Cabling Installation & Maintenance www.cablinginstall.com
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____________________
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:: DESIGN ::
Optical solutions for the
collocation data center
computing and services like SaaS.
SaaS is an application delivery model
Making the case for fiber and certain fiber connection in which an instance of software is
interfaces in high-density data center environments. hosted by the collocation data center
and is used by the end user. The end
DAVID ECKELL, CORNING CABLE SYSTEMS user may be billed through subscrip-
tion or with a pay-as-you-go model.
We read about cloud computing, soft- for moves, adds and changes, while This may sound like an application ser-
ware as a service (SaaS) and man- adhering to industry standards. But vice provider (ASP) model, but there is
aged information technology (IT) ser- fi rst, let’s explore the drivers behind a key difference. SaaS is a multi-tenant
vices, among others, and fi nd that the the need for this type of facility. application that may be provisioned
term “collocation data center” is com- Today’s telecommunications infra- quickly with an automated front end.
mon among these services. But what structure is seeing the traffic growth ASP, on the other hand, requires man-
exactly is a collocation data center? that was expected
At its core, it is a common meet-point in the late 1990s and What major silicon vendors are saying
for businesses to interconnect with early 2000s. The Enterprise
telecommunications and network ser- Wall Street Journal Distance: 0.1–10km 10G <=40G
vice providers. The facility leases cage reported in March in Optical
Rack to rack
space to end users that populate the its Data Hosting and Distance: 1–100m 3.125G 10G 40G
space with their hardware and soft- Data Storage Report Tr
Board to board an
sit
ware, and manage it. Some facilities that analysts are very Distance: 50–100cm 3.125G 6.25G 10G ion 20G
provide less-expensive in-row collo- encouraged by the Electical
Chip to chip
cation services with lockable cabi- data hosting space Distance: 5–50cm 3.125G 6.25G 10G 15–20G
nets as well. The data center portion as well. They see 2004 2006 2008 2010 2012
of the facility provides value-added strong trends for data Source: Silicon vendors
outsourced services for businesses by hosting based on
supplying the hardware, software and current demand and future needs with According to silicon vendors,
customer-facing, front-end and back- networking equipment is trending
the IT support staff.
toward all-optic devices and the
Of major concern in these facilities end solutions. They cited the increased
transition will be largely complete
is the capability of the physical cable consumption of applications and video within a few years.
plant to handle future needs as well content with smartphones as a driver
as today’s requirements. The answer in this space. ual intervention to have an end user up
to this concern involves a complete and running. SaaS provides consider-
view of capabilities, capital expendi- SaaS and clouds mean business able cost savings for the end user and
tures, operation expenses, green initia- A few key drivers for outsourced data mitigates software service level agree-
tives and whether it provides flexibility hosting and storage involve cloud ments while enabling the collocation
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:: DESIGN ::
Energy savings comparison of
data center manager to scale their as there is a comfort level due to skill
10G optical vs. 10G copper
%
offerings with less manual interaction. set or familiarity; however there are 90
Cloud computing is a model that several key reasons to migrate to an
delivers a variety of virtual services, optical physical plant. 85
much like SaaS, to a geographically First, the industry is clearly follow-
diverse group of end users. A cloud ing an optical path. As seen in the fig- 80
computing facility aggregates the ure titled “What major silicon vendors
common features found in a data cen- are saying,” manufacturers of telecom- 75
ter, such as power, cooling, physical munications networking equipment
plant and networking equipment, and are trending toward all-optical devices. 70
48 96 144 192 240 288
spreads those costs across hundreds Network equipment in the enterprise Number of 10G ports
and thousands of users throughout backbone operating at 10 Gigabit
This graph shows the energy-efficiency
the year. It provides the end user with Ethernet (GbE) became all-optical prior gains of using an optical system
massive scalability, access to high-end to 2004. In the period since, the opti- versus a copper system for 10-Gbit/sec
switching equipment, reliability, disas- cal trend has been increasing within transmission. At a density of 288 10-Gig
ports, fi ber offers an 86% efficiency gain
ter recovery and cost savings. the horizontal as data rates move from
over copper.
This is a good-news story for 1 to 10 GbE. As data rates increase
today’s data center collocation man- to 40 GbE and beyond, the landscape SFP+ transceiver consumes 0.5 watts
agers. Over the next few years, even becomes all-optical in the horizontal. of power. A dual-port 10G copper net-
if bandwidth use is conservative, There is no existing guidance from the work interface card (NIC) on a server
the demand for collocation data cen- Institute of Electrical and Electronics card weighs in at 24 watts with the
ter servers and storage will increase. Engineers (IEEE; www.ieee.org) optical SFP+ NIC averaging 9 watts.
However, in order to adequately meet for using 40/100 GbE unshielded or This allows network equipment man-
this demand curve, decisions regard- shielded cabling, and the trend is that ufacturers to provide optical switches
ing legacy and existing telecommu- it will not be included in the future. with three to six times the density of
nications infrastructure will need to This significantly impacts the TCO as current copper-based switches.
be addressed. Questions will surface a completely copper backbone would Added to the cost for the additional
regarding physical media, design con- need to be replaced entirely to sup- power is the need for appropriate cool-
siderations, latency, effects on capital port 40/100 GbE, while existing OM3 ing. According to the Environmental
expenditures and operation expendi- and OM4 fi ber-optic physical plants are Protection Agency (EPA), each unit of
tures incurred to support the physi- well-equipped to handle the migration. additional network power must be com-
cal plant over the long term. A solid While 40 Gbits/sec is available plemented with an equal unit of cool-
approach to designing and refreshing now for Infi niBand and will be avail- ing. For example, a 288 10G optical port
collocation data centers is necessary. able for Ethernet in 2011, some data has 86% enhanced energy efficiency
center managers see a migration to compared to 10G copper, resulting in
Media choices and TCO 40G far in the future, leading them to significant cooling savings over a cop-
Media choice is the fi rst consideration believe that a legacy copper solution per solution. According to researcher
in a new-build or refresh. This decision is warranted. However the total cost IDC (www.idc.com), some estimates
significantly impacts the total cost of of doing so throughout the lifespan of blame up to 60% of data center down-
ownership (TCO) of your data center the physical plant can be consider- time on heat-related issues. With ser-
and, ultimately, the margins that will able. The fi rst consideration is power vice level agreements (SLAs) and the
be generated. At times, it may seem consumption. A typical 10G copper potential for liquidated damages, heat-
like a sound course of action to con- PHY chip consumes six to eight watts related risks are simply not worth tak-
tinue with legacy copper media types of power, while the typical optical ing. As seen in the energy-savings
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:: DESIGN ::
chart, as port count increases in the 300-pound maximum pulling tension, ready for the migration to 40 GbE par-
data center, there is significant energy depending on cable type. As a result, allel optics is a high-density fi ber-
savings in using a fiber-based solution more extensive testing is required to optic solution based on the TIA-942
over a UTP-based solution. certify copper media, which requires Telecommunications Infrastructure
The added benefit of reducing elaborate test equipment. However, Standard for Data Centers.
power and heating/ventilation/air- fi ber-optic testing in high-data-rate
conditioning (HVAC) consumption is environments is fast and cost-effec- Standards-based designs
a greener facility. Each kilowatt-hour tive, which helps to reduce the total This standard was designed with
consumed results in 1.6 pounds of cost of the project as well as the time speed and flexibility in mind. As the
CO2 emissions. By using fi ber optics, to install the physical plant. diagram shows, the design is based
data centers use less power at both At this point, the data center man- on a star topology using a main distri-
the networking level and cooling level.
Because they are using less power,
Star topology per TIA-942
they reduce their carbon footprint and Main distribution
Possible logical and physical architectures for “A” area (MDA)
their costs. As elements of cap-and-
trade or other governmental controls
Caged Caged
are initiated, those facilities with cop- colo EDA EDA EDA EDA HDA EDA EDA EDA EDA colo
per-based infrastructures may face
considerably more costs to offset their
Server HDA HDA HDA HDA ZDA HDA HDA HDA HDA
carbon footprints. farm
for hosted “A” “B”
services
Is copper the fragile medium? HDA HDA HDA HDA ZDA HDA HDA HDA HDA
An additional cost to consider when
installing the physical plant is the frag-
HDA HDA HDA HDA HDA HDA HDA HDA HDA
ile nature of Category 6 and 6A media. colo
As Category 6 and 6A cables have
advanced, they have become increas- This schematic shows a TIA-942 standard-based layout of a collocation data center.
ingly susceptible to noise and alien
crosstalk. While power-intensive digi- ager understands that fi ber-optic cable bution area (MDA) as its focal point. It
tal signal processing on the line card has significant operational and fi nan- is from here that the data center man-
assists in reducing deterministic noise, cial advantages over copper UTP/STP ager establishes a main crosscon-
the physical media must protect itself cable media at 10G. The question is nect that can easily manage moves,
against alien crosstalk through tight how to address the needs of the data adds and changes to facilitate grow-
twists and narrow tolerances for physi- center collocation facility. The data ing customer needs. The MDA feeds
cal separation of copper pairs. center manager must meet the same several areas within the facility and
It is a curious statement to say that reliability, performance and scalabil- can do so in different ways. The advan-
in some respects, the high-data-rate ity requirements that all data centers tage is that it helps to create an effi-
copper plant is more fragile than fi ber- demand, but they must provide these cient infrastructure. In a typical data
optic cable, but it is. For example, in requirements for numerous and some- center configuration, the MDA houses
order to maintain protection against times very different customers, all the core, aggregation and storage area
alien crosstalk, a Category 6A cable within the same facility and all at a network (SAN) switching. In order to
has a maximum pulling tension of 25 quick deployment velocity. The key to do this effectively, high-density fiber-
pounds. A typical fi ber-optic cable being able to provide a scalable solu- backbone cabling with preterminated
found in the horizontal has a 100- to tion that meets today’s needs and is MPO-style connectors should be used.
8 JUNE 2010 Cabling Installation & Maintenance www.cablinginstall.com
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:: DESIGN ::
The benefits include reduced congestion in pathways and
a new world of
spaces, improved airflow and higher-density patching areas. unrivaled integrated solutions
In the diagram, the horizontal distribution area (HDA) at
the cage is performing the traditional function as a cross-
connect, housing the row’s switching equipment. From here
horizontal cabling terminates in the equipment distribution
area (EDA). However, the industry is moving to a top-of-rack
topology in preparation for parallel optics, so this pushes the
HDA to each rack.
This configuration is seen in the bottom row with edge
switches distributed to the top of each rack and terminated
with point-to-point fiber-optic uplinks back to the MDA. The
problem with this scenario is that the home runs back to
the MDA from each HDA do not take advantage of the den-
sity found in fiber-optic cabling. An additional option being
reviewed by TIA/EIA is the addition of a zone distribution
area (ZDA) between the MDA and HDA as seen in the mid-
dle rows. Here high-density backbone cabling extends from
the MDA to a ZDA and terminates with lower-density fiber-
optic cabling at the HDA in each rack, which helps further OCC is recognized as the
improve congestion in the spaces and pathways. gold standard in an industry
With the higher-density MPO-style connectors and that demands speed,
advances in bend-optimized fiber-optic technology, it is now technology, and durability.
possible to terminate more than 2,300 fibers in a 4U rack Our expanded product
offering includes fiber optic
space. It would take 127U to accommodate the same num-
and copper cabling, as well
ber of copper terminations. Providing this level of density as connectivity components
allows the data center manager to build the backbone in designed for commercial,
anticipation of customer needs, while leaving the short runs specialty, and harsh-environment
from the ZDAs to be installed quickly and cost effectively. applications. We have
As we have seen, the trend for data consumption is rising broade
broadened our scope, creating
a singl source of integrated
single
at a tremendous rate. The value of each rack space is increas-
solutio for our customers.
solutions
ing as businesses opt to outsource their hosting, storage and
application needs. In an effort to cut costs and improve densi-
ties within the facility, fiber-optic media is the clear choice. In
order to provide an infrastructure that will meet the demand
of today as well as the requirements of the future, it is critical
to employ an MPO-style preterminated fiber-optic solution
with bend-optimized fiber. This will significantly improve
patching density, minimize congestion in the pathways and 80
800-622-7711
spaces and provide the necessary migration path to parallel C
Canada 800-443-5262
optics that facilitates 40 GbE and beyond. To learn more,
vi occfiber.com or
visit
ca for a free catalog.
call
DAVID ECKELL is systems engineer with Corning Cable
Systems (www.corning.com/cablesystems).
www.cablinginstall.com
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Fits 3x as much.
Go ahead, pull 3x as many cables as usual. MaxCell
can take it. And you’ll only need 1/3 the manpower to
get the job done. Plus you can overlay with MaxCell.
More cables per conduit, less labor, and the ability to
overlay. That’s the flexibility of MaxCell.
www.maxcell.us
__________________ 888.387.3828
More space. More productivity.
10 Y E A R S O F M A X I M I ZI N G P RO D U CTIV IT Y
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:: INSTALLATION ::
Optical fiber cabling and component
specification considerations
is typically easier to terminate and
install in the field than singlemode.
Put optical theory into practice for Additionally, it is always more cost-
optimal network performance. effective to transmit at 850 nm for mul-
timode applications and at 1310 nm for
BY VALERIE MAGUIRE, SIEMON singlemode applications. Finally, opto-
electronics that use multiple transmit
In last month’s issue I provided infor- requirements, as well as optical speci- lasers (e.g. 10GBase-LX4 uses four sep-
mation on fundamentals of optical light fications such as attenuation and band- arate laser sources per fiber) or other
sources and transmission. In this con- width are specified. It is important to multiplexing techniques cost signifi-
tinuation of that discussion, I will pres- keep in mind that these specifications cantly more than optoelectronics that
ent information on the means by which are for the “raw” optical fiber before it is transmit over one wavelength.
that optical theory is put into practice subjected to the cabling process. TIA
by professionals in the networking and and ISO use these optical fiber require-
cabling industries. ments to then specify requirements
Unlike balanced twisted-pair for OM1, OM2, OM3, OM4, OS1
media, optical fi ber cabling can be and OS2 optical fiber cables
considered application-dependent and cabling.
media. This means that consider- While media selection
ations such as distance, application may seem onerous, com-
and equipment cost play a role in the paring the throughput
media selection process. and distance needs in your
The Telecommunications Industry target environment against The XLR8 tool from Siemon combines
Association (TIA; www.tiaonline.org) performance parameters is a good splice activation and mechanical
way to initiate the selection process. crimping into a single step, enabling
and the International Organization for
quick and reliable field termination of
Standardization (ISO; www.iso.org), Although such comparisons may lead
LC and SC connectors.
through reference to specifications to the conclusion that singlemode fi ber
from the International Electrotechnical is the optimum medium under all sce- A good rule of thumb is to consider
Commission (IEC; www.iec.ch) and narios, there are tradeoffs to consider multimode fi ber to be the most cost-
the International Telecommunication related to the cost of optoelectronics effective choice for applications up to
Union (ITU-T; www.itu.int), recog- and application implementation. 550 meters in length.
nize six grades of multimode and sin- In particular, singlemode optoelec-
glemode optical fiber as shown in the tronics rely on much more powerful and Optical fiber cabling configurations
table on page 12. Physical dimensions precise light sources and can cost 2 Optical fi ber cabling is typically
related to the optical fiber, e.g. diam- to 4 times more than multimode opto- deployed in pairs; one fi ber is used
eter, non-circularity and mechanical electronics. Also, multimode media to transmit and the other is used to
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:: INSTALLATION ::
receive. Due to its extended distance common telecommunications rooms, area and the centralized crosscon-
support of applications compared to equipment rooms, telecommunications nect is 90 meters (295 feet). Centralized
balanced twisted-pair cabling, optical rooms, and telecommunications enclo- cabling requirements are specified in
fi ber cabling is the perfect media for sures within a commercial building. ANSI/TIA-568-C.0, ANSI/TIA-568-C.1,
use in customer-owned outside plant Backbone cabling must be configured and ISO/IEC 11801 Ed2.0.
(OSP), backbone cabling, and central- in a star topology and may contain one Optical fi ber cabling may also be
ized cabling applications. (main) or two (main and intermedi- used in the horizontal cabling infra-
Customer-owned OSP cabling is ate) levels of crossconnects. Backbone structure, although there are no provi-
deployed between buildings in a cam- cabling requirements are specified in sions allowing extended distance in
pus environment and includes the ter- ANSI/TIA-568-C.0, ANSI/TIA-568-C.1, the TIA and ISO standards.
minating connecting hardware at or and ISO/IEC 11801 Ed2.0. Horizontal cabling is deployed
within the structures. Interestingly, Centralized optical fiber cabling between the work area and the tele-
customer-owned OSP cabling is typi- may be deployed as an alternative to communications room or enclosure.
cally intended to have a useful life in the optical crossconnect to support Horizontal cabling includes the con-
excess of 30 years, so great care should centralized electronics deployment in nector and cords at the work area and
the optical fi ber patch
Supportable application distances by fiber type (meters)
panel. A full crosscon-
Application OM 1 OM2 OM3 OM4 OS1/ OS2
nect or interconnect may
Wavelength 850 1300 850 1300 850 1300 850 1300 1310 1550
be deployed along with
FDDI PMD 2,000 2,000 2,000 2,000
an optional multi-user
FDDI SMF-PMD 10,000
telecommunications out-
10/100Base-SX 300 300 300 300
let assembly (MUTOA) or
100Base-FX 2,000 2,000 2,000 2,000
consolidation point (CP)
1000Base-SX 275 550 800 800
for a total of four connec-
1000Base-LX 550 550 800 800 5,000
tors in the channel. The
10GBase-S 33 82 300 550
maximum horizontal cable
10GBase-LX4 300 300 300 300 10,000
length shall be 90 meters
10GBase-L 10,000
(295 feet) and the total
10GBase-LRM 220 220 220 220
length of work area cords,
10GBase-E 40,000
patch cords or jump-
40GBase-SR4 100 125
ers, and equipment cords
40GBase-LR4 10,000
shall be 10 meters (32
100GBase-SR10 100 125
100GBase-LR4 10,000 feet) for both optical fi ber
100GBase-ER4 30,000 and balanced twisted-
pair cabling channels.
be taken to specify robust cabling single-tenant buildings. Centralized Horizontal cabling requirements are
media. Requirements pertaining to optical fi ber cabling supports direct specified in ANSI/TIA-568-C.0, ANSI/
customer-owned outside plant cabling connections from the work area to the TIA-568-C.1, and ISO/IEC 11801 Ed2.0.
and pathways can be found in ANSI/ centralized crossconnect via a pull-
TIA-758-A and BS EN 50174-3. through cable and the use of an inter- Optical fiber cable
Backbone cabling is deployed connect or splice in the telecommuni- The optical fi ber that enables light
between entrance facilities, access- cations room or enclosure. Note that transmission is actually an assembly
provider spaces, service-provider the maximum allowed distance of the of three subcomponents: the core, the
spaces, common equipment rooms, pull-through cable between the work cladding, and the coating. The core is
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:: INSTALLATION ::
made of glass (or, more accurately, sil- are then encircled with aramid yarns aluminum, interlocking steel armor, or
ica) and is the medium through which for strength, and then enclosed by an dual jackets may be applied for addi-
the light propagates. The core may overall flame-retardant thermoplastic tional protection against crushing and
have an overall diameter of 9 μm for jacket to form a fi nished optical fi ber rodent damage. Supported fi ber counts
singlemode or 50 μm or 62.5 μm for cable. For indoor cables with higher are typically between 12 and 144.
multimode transmission. Surrounding than 12-fi ber counts, groups of jack- Indoor/outdoor optical fi ber cables
the glass is a second layer of glass eted optical fi ber cables (typically 6- or offer the ultraviolet and water resis-
with a vastly different index of refrac- 12-fi ber count) are bundled together tance benefits of outdoor optical fi ber
tion that focuses and contains the light with a central strength member (for cables combined with a fi re-retar-
by reflecting it back into the core. This support and to maintain cable geom- dant jacket that allows the cable to be
second layer is called the cladding etry) and are enclosed by an overall deployed inside the building entrance
and, regardless of the glass core con- flame-retardant thermoplastic jacket. facility beyond the maximum 15.2-
struction, has an overall diameter of Supported fi ber counts are typically meter (50-foot) distance that is speci-
125 μm. Combining the core and clad- between 2 and 144.
ding diameters is the source of optical Outdoor (also
fi ber descriptors, such as 50/125 μm or known as outside
62.5/125 μm, that are applied to opti- plant or OSP) optical
cal fi bers commonly used for telecom- fi ber cables are used
munications applications. The purpose outside of the build-
of the outermost layer, called the coat- ing and are suitable
ing, is to add strength and build up the for lashed aerial, duct,
outer diameter to a manageable 250- and underground con-
μm diameter (about three times the duit applications. To
diameter of a human hair). The coat- protect the optical
Several of the optical interconnection technologies
ing is not glass, but rather a protec- fi ber core from water described in this article are shown here. Clockwise from
tive polymer such as urethane acrylate, and freezing, up to 12 upper left are MTP/MPO-style trunking cable assemblies,
that may be optionally colored for iden- 250-μm optical fi ber duplex LC-connected optical fi ber cables, plug-and-play
array modules (one with MPO/MTP-style connectors
tification purposes. cores are enclosed in
showing and the other with LC connectors showing),
Cabling optical fi bers makes them a loose buffer tube and a pass-through adapter plate.
easier to handle, facilitates connec- that is fi lled with
tor termination, provides protection, water-blocking gel. For up to 12-fi ber fied for OSP cables. Note that there is
and increases strength and durability. applications, the gel-fi lled loose tube no length limitation in countries out-
The cabling process differs depend- is encircled with water-blocking tapes side of the United States that do not
ing upon whether the optical fi bers are and aramid yarns and enclosed within specify riser- or plenum-rated cabling.
intended for use in indoor, outdoor, or an overall ultraviolet and water-resis- The advantage of using indoor/outdoor
indoor/outdoor environments. tant black polyolefi n jacket. For out- optical fi bers cables in this scenario is
Indoor optical fi ber cables are suit- door cables with higher than 12-fi ber that the number of transition splices
able for inside (including riser and ple- counts, groups of loose buffer tubes and hardware connections is reduced.
num) building applications. To facili- (typically 6- or 12-fi ber count) are bun- Indoor/outdoor optical fi ber cables are
tate connector terminations, a 900μm dled together with a central strength similar in construction to outdoor opti-
plastic buffer is applied over the opti- member and water-blocking tapes and cal fi ber cables except that the 250-μm
cal fi ber core, cladding, and coating aramid yarns and then enclosed within optical fi ber cores may be either tight
subassembly to create a tight buff- an overall ultraviolet and water-resis- buffered or enclosed within loose buf-
ered fi ber. Up to 12 tight buffered fi bers tant black polyolefi n jacket. Corrugated fer tubes. Loose tube indoor/outdoor
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:: INSTALLATION ::
optical fi ber cables have a smaller alignment sleeve. These components the reason why different optical fi ber
overall diameter than tight buffered work in tandem to retain and prop- types, including 62.5-μm and 50-μm
indoor/outdoor optical fi ber cables, erly align the optical fibers in the plug- multimode fi ber, should never be
however tight buffered indoor/outdoor adapter-plug configuration. The inter- mixed in the same link or channel.
cables are typically more convenient to nal connector ferrule is fabricated Optical fi ber breakout kits are used
using a high-preci- to facilitate termination of loose-tube
sion manufacturing optical fi bers used in indoor/out-
Centralized optical fiber cabling using process to ensure door and outdoor applications. Once
an interconnection
that the optical fiber the water-blocking gel is thoroughly
Telecommunications
room (TR) is properly seated removed from the optical fi bers, the
Work area (WA) and its position is breakout kit allows furcation tubes
Horizontal cable
90 m (295 ft. max) tightly controlled. (typically 1.2mm to 3.0mm in diam-
Work area
equipment The high tolerances eter) to be installed over the 250-μm
cord of the alignment optical fi bers, increasing the diameter
Work area outlet sleeve ensure that and forming a short “jacket” so that
Equipment the optical fibers the optical fi bers may be terminated
room
held in place by the to the desired optical fi ber connector.
ferrule are aligned Selection of the correct furcation tube
as perfectly as pos- ensures compatibility with all optical
Equipment cord connected to sible. Although fi ber connectors.
centralized equipment
more expensive, Users can choose from many optical
ceramic alignment fi ber connector options.
Shown here is a typical schematic for centralized optical
fi ber cabling using an interconnection; the centralized sleeves maintain Traditional optical fiber connec-
system supports direct connections from the work area to slightly tighter tol- tors are represented by the SC and
the centralized crossconnect via a pull-through cable and erances than metal ST connector styles. These two types
the interconnect.
or plastic alignment of optical fiber connectors were rec-
terminate because they do not contain sleeves, are not as susceptible to per- ognized when optical fiber cabling
water-blocking gel or require the use of formance variations due to temperature was described in the first published
breakout kits (described later). fluctuations, and may be specified for TIA and ISO/IEC telecommunica-
extremely low-loss applications. tions cabling standards. The ST con-
Optical fiber interconnections Accurate plug-adapter-plug align- nector features a round metal coupling
Unlike the plug-and-jack combina- ment minimizes light energy lost at the ring that twists and latches onto the
tion that makes up a mated balanced optical fi ber interconnection and main- adapter and is only available as a sim-
twisted-pair connection, an intercon- taining precision tolerances becomes plex assembly (two assemblies are
nection is used to mate two tight-buff- especially critical as the optical fi ber required per link or channel). SC con-
ered optical fibers. An optical fiber diameter decreases. For example, if nectors feature a quick push-pull latch-
interconnection typically consists of two 62.5-μm optical fi bers are off-cen- ing mechanism and have an advantage
two plugs (connectors) that are aligned ter by 4 μm in opposite directions, then in that they may be used in conjunc-
in a nose-to-nose orientation and held 13% of the light energy escapes or is tion with a duplex clip that more eas-
in place with an adapter (also called lost at the interconnection point. This ily supports the interconnection of the
a coupler or bulkhead). The perfor- same misalignment in a 9-μm single- two optical fibers in a link or channel.
mance of the optical fiber interconnec- mode fi ber would result in almost a SC optical fiber connectors are gener-
tion is highly reliant upon the connec- total loss of light energy. The criti- ally recommended over ST optical fiber
tor’s internal ferrule and the adapter’s cal nature of the core alignment is connectors for use in new installations
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:: INSTALLATION ::
Optical fiber cross-section The most common method. The main difference between
SFF interface is the the MT-RJ and LC optical connector is
Coating
LC connector, with related to the performance of the inter-
the MT-RJ having nal ferrule. The LC’s internal ferrule
Core
some limited legacy maintains sufficiently tight tolerances
Diameter market presence. to fully support both singlemode and
Core 9μm, 50μm, or 62.5μm
Cladding Cladding 125μm Both interfaces fea- multimode applications, while the
Coating 250μm
ture duplex configu- MT-RJ connector is recommended for
rations and a small use in legacy applications only. Field
Singlemode fi ber cores are 9 μm in diameter, while
pluggable form with termination of MT-RJ connectors is
multimode fi ber cores may be 50 or 62.5 μm. Regardless of
core size, the cladding is 125 μm and the coating 250 μm. external plug latch not recommended for singlemode
that is approximately applications.
due to their duplexing capability. Both the same size as the 8-position modu- Array optical fi ber connectors are
ST and SC connectors may be field- lar plug used for copper connections. the newest recognized style of opti-
terminated using an epoxy/polish or The LC connector may be field termi- cal fi ber interfaces and are intended to
mechanical splice method. nated using an epoxy/polish method support extremely high-density envi-
Small form factor (SFF) refers to a or mechanical splice method. The ronments as well as emerging tech-
family of optical fi ber interfaces that MT-RJ connector is field terminated nologies such as 40GBase-SR4 and
support double the connector density using a traditional no-epoxy/no-pol- 100GBase-SR10 that will require more
of traditional optical fi ber connectors. ish mechanical splice termination than two optical fi bers per link or
_______________
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