metro delivery services

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OPTICAL TECHNOLOGIES,
COMMUNICATIONS
APPLICATIONS, AND INDUSTRY
®
MAY/JUNE 2012
VOLUME 29 NO. 3
ANALYSIS WORLDWIDE
WWW.LIGHTWAVEONLINE.COM
___________________________
Packet-optical transport
systems: Platforms for
metro transformation
___________________________
_________________________
Packet-optical
transport for
metro
services
delivery
3
EDITORIAL /// Don’t go there
By STEPHEN HARDY
10 CWDM solves wireless
backhaul “router to
tower” issues
CWDM combines low cost,
flexibility, and efficiency to meet
wireless backhaul requirements.
By DR. FRANCIS NEDVIDEK
and DAVID ATMAN
15 Better backhaul with
MPLS to the cell site
MPLS improves backhaulnetwork efficiency and resiliency,
while enabling flexibility
and service customization.
By NIR HALACHMI
20 OFC/NFOEC 2012:
The interviews
Catch Lightwave’s exclusive
interviews with leading
industry decision-makers.
21 “Soft decision” FEC
benefits 100G
The latest generation of
forward error correction,
soft decision FEC offers
greater reach and other
performance improvements.
By RANDY EISENACH
________________________
BY FRANK WIENER , Cyan
systems offer world-class
transport, and more important,
a foundation for transformation
to more profitable softwaredefined metro networks.
What’s ahead for
multimode-fiber
communication systems?
___________________
__________________
____________________________
BY GASTÓN E. TUDURY, Ph.D.,
and AL BRUNSTING, Ph.D.
No standard could predict that
some assumptions about the
physical phenomena expected
to limit optical-link performance
would become obsolete. But
multimode-fiber communication
has now reached this point.
Death of the OB van
_______________________
BY PER LINDGREN , Net Insight
It’s time for the outside broadcast
(OB) van to worry about the
future. Fiber networks are
becoming more commonplace in
arenas and media environments
and slowly transforming
production workflows,
especially for live events.
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MAY/JUNE 2012
EDITORIAL
3
STEPHEN HARDY
Don’t go there
hose who remember the optical
bubble of the early part of this century
likely would tell you that our current
times are nothing like those heady years. No
one in the optical communications business
and route diversity have led to new links
between financial centers. The underseasystem market has exploded, with market
research firm Telegeography noting that the
past two years have seen the launch of 19
submarine-cable systems.
Telegeography reports
that 33 additional systems
Click to view
are on the books for 2012
Stephen's video blog
and 2013, despite what the
company says is “tremen(Having trouble? Click here.)
dous untapped potential
capacity on many existing
submarine cables.”
is swimming in cash, venture capitalists
Such projects have led to the installaare not tripping over themselves to supply
tion of about 19 million miles of fiber in
even more money, and more companies
the U.S. alone last year, according to CRU
are being consolidated than created.
Group. That’s the most fiber deployed
But on one point they would be wrong.
in any one year since 2000. And we all
Just as in the early 2000s, there’s a ton
know what happened after that, right?
of fiber-optic cable being installed.
Two words: “fiber glut”
National broadband plans have driven
Not surprisingly, the current fiber
fiber to homes, businesses, and anchor instiboom has some in the financial
tutions. The opportunities in low latency
T
FOLLOW STEPHEN ON
____________________________________
sector nervous. There’s still too much
capacity out there, many fear.
Are these concerns warranted?
Not yet, I don’t think.
The principal difference between
what occurred in 2000 and the current
fiber builds is location. At the apex of the
previous boom, most carriers built capacity
between the same cities and along the
same routes. They seemed to believe
that infinitely growing Internet traffic
would require infinite amounts of fiber.
That belief proved wrong, of course.
Fortunately for the industry (and those
paying for today’s fiber installations),
the current catalyst in most instances is a desire to put fiber where it
presently doesn’t exist. The broadband build-outs represent the most
salient example of this trend. However,
the same could be said for a variety of
middle-mile and alternative backbone
installations. Fiber to the tower initiatives fall into this category as well.
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continued
The riskiest projects are aimed
at offering low-latency routes, either
terrestrial or undersea. There’s no
guarantee there will be enough
demand to pay the build costs – particularly if operators of existing routes
can find ways to lower the latency
figures on their plant. The same could
be said for builds whose business
cases rest upon route diversity.
The trick to avoiding over-capacity
rests in how much fiber to install in
these new projects. There seems
little reason, particularly in backbone
and middle-mile projects, not to
add a little fiber-count cushion. The
question then for fiber suppliers is,
what happens to demand once the
current round of builds concludes?
For now, I’m betting most would
rather not go there just yet. They’re too
happy with where they are right now.
Be the
LabMaster
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MAY/JUNE 2012
Packet-optical
transport for
metro
services
delivery
By ROBERT KEYS
Five elements to ponder
when evaluating
packet-optical transport
systems for the metro.
S THE “ONRAMP” for
A
wholesale, consumer, and
business traffic, the metro
network is rapidly becoming the
most critical link in the valueadded services delivery chain
(see Figure 1). This trend is
unfolding in an environment where
bandwidth demands are increasing
exponentially but budgets to add
capacity remain constrained.
Meanwhile, subscriber churn
has reached an all-time high and
competition has continued to escalate.
New strategies must be developed
to transform metro services delivery
– or else content and service
providers risk commoditization.
Packet-optical transport platforms
can enable network service providers to capitalize on new revenue
opportunities while overcoming the
metro network’s challenges. We’ll
present the points network planners
should consider to determine the
optimal approach for transforming
legacy metro infrastructures into new
efficient networks that can profitably
handle large volumes of over-the-top
5
video, cloud computing, and mobile
broadband traffic – and capture the
new revenue-generating opportunities that accompany this transition.
The metro problem/opportunity
Unprecedented levels of traffic
growth have pushed many existing
metro networks to the brink
(see Figure 2). For example:
• Worldwide subscriber spending for online video soared to $3.5
billion in 2011 (Strategy Analytics).
• In the U.S. alone, 181 million people
watched online video content
in January 2012 – or 58% of the
U.S. population (comScore).
• Netflix consumes as much as
30% of the Internet’s bandwidth
during peak hours (Sandvine).
• One billion consumers will own
smartphones by 2016, with mobile
spending reaching $1.3 trillion by
then (Forrester
Research).
ROBERT KEYS is
chief optical architect
at BTI Systems
y
.
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Experience
the Power
of Dow Inside
Access
Metro
Core
Mobile networks
Content
providers
Content
delivery
networks
Services delivery
quality of experience
lives in the metro
Exchanges
Internet
FIGURE 1. The
“onramp” for wholesale, consumer, and business traffic,
the metro network is ideal for enabling high-value services.
• There will be 1.8 billion broadband subscribers worldwide
by 2014 (Infonetics Research).
• The global cloud services
market is anticipated to triple
in size over the next four years
with a compound growth rate
of 29.4% to reach revenues of
$66 billion in 2016 (Ovum).
Yet the formidable challenges this
growth presents come with a multibillion-dollar opportunity for new
services and revenues. The necessary network transformation starts
with a reevaluation of existing infrastructures. The resulting plan should
enable providers to migrate their
networks and monetize assets and
market services, yet control capital
and operational expenditures.
Traditional transport networks
feature discrete optical and packet
layers with distinct networking equipment, management interfaces, and
provisioning systems. Fixed optical
layers are expensive to manage
and maintain over time and represent inherent risks. They require
user-intensive procedures and significant preplanning. These legacy
optical networks cannot ensure
efficient support of increasing
bandwidth demands. Additionally,
legacy optical networks are often
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Is Your 100G Testing Limited by the Speed of Your BERT?
OTT video
Metro
service
providers
Mobile
broadband
Cloud
computing
FIGURE 2. Growth
in over-the-top (OTT)
video, cloud computing, and
mobile broadband are driving
bandwidth demands in the metro.
difficult to provision, which can
make it hard for a network operator to move quickly to add services
to win important new business.
Many metro-network operators
also have had limited visibility into
or control of the upper layers of the
network stack and are thus unable to
implement service-level agreements
(SLAs) based on application or content
type. Notably, this deficiency also
precludes their ability to influence
IP video, rich media, and other
bandwidth-intensive, delay-sensitive
traffic flows. Today, metro services
networks have to be able to support
the breadth of services based on:
• Applications, industry verticals, and
specific customer requirements.
• The ability to move large
amounts of traffic into, across,
and out of the network.
• The creation of services, assurances, and delivery.
• Highly leveraged, optimized assets
for a better return on investment.
Accommodating growth and
accelerating services delivery
requires that service providers
identify and proactively address
issues of scalability, capacity
expansion, ease of use, management, and costs. Additionally,
providers must seek strategies to
move up the value chain to gain
new revenues while cost-effectively managing the enormous
growth of content (see Figure 3).
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®
FEATURE
alleviate capacity issues and network
inefficiencies to improve the customer quality of experience (QoE) and
enable the delivery of rich new highvalue services. There are five key
considerations for a winning strategy.
Reduce complexity and improve
scalability by converging Ethernet
and optical service layers into a
converged packet-optical infrastructure. Consider starting the network
transformation by converging service
layers to create a simpler, more
dynamically scalable network with
fewer layers, less equipment, and
unified operations, administration,
and management. Converged optical
and Ethernet layers will consolidate
equipment and cabling; save energy,
cooling, and facility costs; and reduce
expenses. This strategy also will
create a solid foundation to optimize
bandwidth and accelerate the
delivery of rich high-value services.
Streamline provisioning and
troubleshooting functions to achieve
end-to-end visibility into services
and customers. Converged network
layers eliminate the need for separate
organizations to handle packet and
optical traffic, a structure that’s costly
and inefficient. By breaking down
the “wall” between the Ethernet and
optical layers, network operators
can easily adjust transport capabilities and realize end-to-end visibility
of service demands and customer
requirements. With a real view into
what’s happening in the network,
operators can deploy new services quickly, scale the network almost
automatically, and make better
decisions to alleviate bandwidth
strain while freeing resources.
Analyze, monitor, and control
services based on content or application type to reduce strain on
bandwidth and make more effective
use of resources. End-to-end network
visibility supports the development
of new revenue-generating services
that include SLAs. The ability to keep
track of traffic ensures delivery of
required levels of bandwidth and low
latency for consumers and businesses and creates a clear competitive
advantage – and the opportunity to
charge SLA premiums. Network-view
Internet services
Carrier Ethernet
services
MAY/JUNE 2012
Service-centric management
End-to-end service
management
Application-aware services
Application and
content intelligence
Packet-optical networking
Dynamically scalable
capacity
8
Ethernet services
Wavelength
services
Optical services
FIGURE 3. Service
providers require a services delivery framework that
addresses scale, end-to-end service visibility, and application awareness.
analytics can also help use resources
more effectively. For example, analytics can help determine if certain
types of traffic, such as Netflix,
should be stored in a cache device
closer to the subscriber to reduce
bandwidth strain and improve QoE.
Create new value-added or tiered
services with assured QoE based
on the ability to intelligently prioritize traffic flows. With the ability to
monitor and control traffic, metronetwork operators can create
new service bundles for subscribers, such as unlimited high-speed
social networking or YouTube
access. Service bundles can help
reduce customer churn and act
as a differentiator to secure new
subscribers. Traffic can be prioritized
based on customer demands rather
than treating all traffic with the same
level of importance, enabling more
efficient use of bandwidth resources
without having to add new equipment.
Use integrated platforms to move
up the value chain, participate in
new revenue streams, and avoid
marginalization. Service providers
control the QoE of the subscriber.
Consumers expect high-quality,
predictable experiences, especially
when viewing purchased content.
Dissatisfaction drives subscriber
churn. An intelligent, converged
infrastructure with analytics enables
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service providers to create
Taking an active role
These are exciting – and challenging
alternatives to conventional content
– times for metro-network operadelivery networks. Such infrators. Digital media is pervasive and
structure also supports two-sided
growing, especially with the prolifebusiness models in which operaration of mobile smart devices. A data
tors capture incremental revenues
point: Apple has sold more than 55
from upstream content providers
million iPads since
and downstream
its launch in 2010,
content consuLEARN MORE
with an additional 55
mers. Metro
million expected to
providers thus
FOR MORE INFORMATION
be sold in 2012. With
can become
on packet-optical
a new iPad model
part of the
transport systems,
Article
just being unveidigital media
READ:
“Packet-optical transport
led, those numbers
distribution
systems: The new POTS”
may well increase.
chain, building
Metro service provirelationships with
ders can avoid the
content provirisks of commoditization by transforders and aggregators by offering
ming their networks and becoming
SLAs and detailed subscriber inforactive participants in the digital media
mation in exchange for subscription
ecosystem. By doing so, they will
commissions or advertising revenue
increase margins, grow revenues,
sharing. Also, metro-network
and be more competitive.
operators have the opportunity to
introduce premium service bundles
(as mentioned earlier) to consuSHARE THIS ARTICLE
mers to boost revenues, margins,
and subscriber base expansion.
_______________________
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®
FEATURE
CWDM combines
low cost,
flexibility, and
efficiency to meet
wireless backhaul
requirements.
MAY/JUNE 2012
10
By DR. FRANCIS NEDVIDEK AND DAVID ATMAN
CWDM solves wireless backhaul
‘router to tower’ issues
T
HE AVALANCHE of mobile data
traffic around the world is exposing
vulnerability in the wireline-based
backhaul infrastructure: a bottleneck
in the first mile “tower to router” link.
Classic fiber exhaust explains much
of this problem. There’s simply not
enough capacity to accommodate the
increasing number of gigabit and 10G
links. Another factor is the desire – or
even requirement – of many wireless
carriers for dedicated links through their
connectivity supplier’s network. They
may even demand dedicated backhaul
fiber strands to connect access and
core meshes with mobile tower sites.
Let’s examine first-mile fiber challenges from several angles. We’ll survey
the options and underscore the advantages of CWDM, look at the outside plant
DR. FRANCIS NEDVIDEK
K is CEO of Cube Optics
p
AG.
DAVID ATMAN is president off Lindsay
y Broadband Inc.
(OSP) connectivity involved in upgrading backhaul architectures, show how
CWDM can expand fiber capacity while
eliminating network elements, and
look at CWDM’s ability to create virtual
fibers and add even more capacity.
The value of CWDM
Before assessing the technology
options, here are the requirements
that operators must satisfy in their
first-mile backhaul networks:
• Segregation of bandwidth on a
per-wireless-carrier basis, according
to service-level agreements (SLAs).
• Guaranteed bandwidth of up to 10
Gbps per first-mile backhaul link.
• Uncomplicated and reliable operation (truck-roll avoidance).
• Provisioning simplicity.
• Reach of up to 80 km “tower
to the router” in the first mile
but typically much less.
• OSP environmental hardening.
• Ability to preserve legacy 1550or 1310-nm fixed connections.
The technology options for this
portion of the network include
active optical networking, passive
DWDM, and passive CWDM.
Active optical. As an approach to
address wireless backhaul congestion, active optical networking equipment
typically amounts to overkill. The
complexity of active methods presents
an abundant superset of features and
functionality that the operator pays for
in hardware costs, software licensing,
ongoing maintenance, electrical power,
and upgrade costs. Segregating or partitioning bandwidth occurs at a logical level
within the active electronics. But these
higher-level logical approaches yield only
best-effort bandwidth performance when
emulating individual physical connections.
Then there are costs related to
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MAY/JUNE 2012
®
FEATURE
CWDM’s backhaul edge
training personnel to maintain
and manage proprietary network
gear. Associated operating, sparestocking, and repair costs further
diminish return on investment (ROI).
Active optical equipment is best
placed in close proximity to the
network core; unsophisticated and
low-cost passive gear belongs in the
access and middle-mile networks.
Passive DWDM. DWDM represents a more practical option. Where
the number of connections or channels
exceeds 16 and creates transmission
capacity requirements of up to 160
Gbps (as in 10 Gbps × 16), DWDM
technology may offer a viable alternative. But operators should be aware
that DWDM is not the least expensive
option and will not accommodate the
plethora of form factors – from pedestal
to line-card to central office (CO) rack
– that characterize the first mile of the
network. In that light, DWDM compares
unfavorably with CWDM schemes.
Passive CWDM. An optimal
balance between right-sized
functionality and right-sized cost,
CWDM satisfies the best-fit rule
of Occam’s razor: Essentially, the
simplest solution, all things being
equal, is the best among more
complex solutions. CWDM expands
the capacity of existing fiber infrastructure by enabling individual
fibers to function as multiple
optical links; each link supports
at least 10 Gbps over spans of up
to 80 km. CWDM is unique in its
ability to support legacy 1310- and
1550-nm single-fiber connections
while permitting additional CWDM
links via the same fiber pair.
Like DWDM, CWDM physically
partitions connections at the physical layer into separate wavelengths
that provide a unique and exclusive optical connection for each
10-Gbps traffic channel. The flexibility of CWDM facilitates cell-site
capacity planning and design. Adding
CWDM to an existing legacy fiber
network is straightforward; both
previously deployed and newly introduced channels are handled similarly,
which means legacy channels are
relayed and routed undisturbed.
CWDM thus provides the simplest,
most robust, and yet most multifaceted option for future expansion.
Backhaul upgrades
Several connectivity issues affect
upgrades to a wireline network
operator’s backhaul architecture.
In a typical radio-access-network
OSP backhaul network, the feeder
cable often extends several kilometers from the CO or aggregation
point to a remote terminal (RT) in
the vicinity of the wireless tower or
cell site. In such situations, it is not
uncommon to be confronted with an
2G / 3G / 4G /
LTE / WiMax
UMTS
4G / LTE / WiMax
LTE
WiMax
3G base station
CDMA
UMTS
UMTS
Base station
Base
station
Cell site aggregation
STM-1 / STM-4
OC-3 / OC-12
Ethernet
backhaul
Ethernet
backhaul
4G node
WiMax
LTE
Base
station
ATM or IP
over TDM
GbE
4G / LTE / WiMax
gateway
FIGURE 1. Linear
2G / 3G
LTE
Remote radio hub
2G / 3G
MSC
existing link comprising only a limited
number of 6, 8, or 12 fiber strands,
with electrical supply lines accommodating the optical cable along
the same trench to the distribution
terminal (DT). On the radio-networkcontroller (RNC) side, twisted-pair or
coax carries mobile telephone and
community microwave relay services from the tower. WiMax and
other private dedicated or industrial
and security antennas may be
co-located at the tower as well.
It is relatively easy to expand
legacy installed fiber that supports
CDMA
WiMax
12
architecture with intermediate add/drop nodes.
Ethernet Base station
backhaul ATM over
TDM
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®
FEATURE
low-bandwidth 2G and some 3G
wireless services by upgrading the
speeds of the CO and RT transceivers or adding blocks of four CWDM
channels. Bandwidth-hungry 4G
and LTE services in most cases,
however, will require expansion of
the optical bandwidth of the CO-to-RT
link and very possibly converting the RT and DT links and the
coax tower drops to fiber as well.
Whether installing twisted-pair,
coax, electrical power grid cabling,
or fiber, trenching and duct engineering represent the majority of
costs. When the opportunity arises,
laying flexible and future-proof
optical cable (48-plus strands) yields
a very high ROI and virtually eliminates future capacity restrictions.
By the same token, the business
case for upgrading the CO-to-RT
link (middle mile) part of the OSP
using CWDM wins handsomely over
any option involving retrenching.
Capacity expansion
Boosting the capacity from the CO
straight through to the DT via WDM
can easily multiply the bandwidth
of existing DT fibers – and eliminate the RT in the process. Two
scenarios that enable new efficiencies involve connecting with wireless
service providers (WSPs) and linking
up a series of cell sites. Not all configurations, however, are amenable
to these kinds of upgrades.
The first scheme increases fiber
capacity from the CO to the DT, but
also extends the CWDM channels all
the way to the WSPs. There is ample
fiber in today’s fiber cables to permit
dedicated fibers running from the
CWDM enclosure to the wavelength
multiplexers that belong to each WSP.
When several WSPs share facilities at each tower, individual gear
may be compartmentalized into a
so-called base station hotel, or fibers
may run directly to towers outfitted
with remote radio head technology.
Another architecture that takes
advantage of CWDM consists of
stitching together a series of cell
sites along a fiber (four in this
case) using the add/drop capabilities of CWDM. One such example
CWDM / DWDM
MUX / DEMUX
Headend, central office
Remote terminal
FIGURE 2. Using
CWDM to multiply
bandwidth for critical fiber-limited sections.
is shown in Figure 1. Here a CO
serves four cell sites with four pairs
of wavelengths. A wavelength pair
is added or dropped at each cell
site. Since cell sites may reside tens
of kilometers from the CO, minimizing insertion loss and selecting the
appropriate optical power of transceivers become an essential priority.
Individual cell sites may be housed
in pedestals, small cabinets, and
even suspended or buried in pods.
Depending on the particular
regulatory situation or jurisdiction,
not all WDM upgrade configurations may be practicable. Regulations
may prohibit certain digital
multiplexing of data or channels
from particular subscribers. Others
traditionally prefer dedicated fiber
MAY/JUNE 2012
13
strands. Circumstances that require
dedicated access fiber(s) may
be accommodated in the middle
mile through consigning WDM
capacity or other fiber strands.
Furthermore, transmission reliability
and incorruptibility concerns typically
arise with respect to latency. Networks
that transport SONET/SDH overhead
or Frame Relay or pseudowire protocols strive to eliminate delays from
provisioning, queuing, buffering,
switching, or other electronic processing. WDM technologies offer one
of the more effective approaches to
minimizing latency because end-toend delays are essentially reduced to
the propagation speed of the optical
signal through the optical link.
Virtual fibers, more capacity
An alternative architecture uses
CWDM multiplexers to partition a single fiber strand (or pair)
and in effect create virtual fibers.
CWDM multiplexers are placed
at the CO and in a remote enclosure, as depicted in Figure 2.
A CWDM system uses 1 to 16
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®
FEATURE
Ethernet
MAY/JUNE 2012
14
CDMA LTE
wavelengths based
on the ITU-T standard
xDSL UMTS WiMax
CO / hub
PON
headend
grid (and two more
channels of the full
CWDM / DWDM
MSAN
RNC / gateway
FTTx
MUX / DEMUX
ITU complement of 18
channels if low “water
peak” fiber has been
deployed). The transmission equipment at
the cell site can use
CWDM small-formFIGURE 3. Upgrade of an existing access network
factor pluggable (SFP)
to support additional wireless traffic.
transceivers. If not,
separate CWDM transponders may
the WDM equipment. Alternatively,
convert low-power 1310-nm signals
adding or dropping more wavelengths
to the desired CWDM wavelength.
can increase link capacity.
CWDM SFPs and transponders
Boosting capacity of the OSP infrareliably span fiber transmission
structure using CWDM technology
distances of 60 km or more.
adequately relieves wireless bandwidth
A CWDM system can scale as
bottlenecks in a vast majority of cases.
capacity demand from the wireless
But for situations where 18 CWDM
subscribers grows. Operators can
channels do not suffice, overlaydedicate additional wavelengths to
ing DWDM wavelengths onto the
particular wireless sites in anticiCWDM grid permits further expanpation of “lighting up” addition
sion of transmission capacity.
channels. Flexible transmission rate
But the option to adopt DWDM
per wavelength permits wireless
connectivity carries the attendant need
providers to increase bandwidth to
for controlled environment enclosures
particular cell sites, independent of
and deployment of the appropriate
(more costly) DWDM transceivers.
DWDM upgrades or deployments also
require the right electrical power to
support the additional equipment and
thermal regulation. Supplementary
space requirements may arise in RTs
that serve as DWDM add/drop locations.
Finally, operators may need to
add wireless capacity to existing
access networks where the network
subscription areas overlap with
cell phone, same-service-provider WiMax, and even microwave
and private wireless footprints. In
such circumstances, operational continuity and integrity of the
legacy subscription base must
be maintained while augmenting
bandwidth to individual wireless sites.
Figure 3 demonstrates such a situation. The network segment typically
composes part of a ring in urban
areas, but the topology often branches
to a linear configuration in rural
or remotely populated areas. Both
configurations are possible where
new wireless capacity supplements
the existing 10-Gbps connectivity
that links subdivisions, enterprises,
and institutions to the co-location
sites, distribution hub, and headend.
Today and tomorrow
The rising tide of wireless
backhaul traffic is creating bottlenecks in the wireline networks
that serve them. CWDM relieves
backhaul bandwidth exhaustion in
harmony with the dictum that the
simplest choice, all things being
equal, tends to be the best.
Applicable in a range of scenarios,
CWDM demonstrates admirable flexibility – especially when combined
with highly reliable, customizable,
and compact low-cost components.
The technology solves the problem
of future expansion with a minimalist
approach: only as much as you need,
when you need it, without expensive or unnecessary extras. CWDM
is thus able to remedy the “tower to
the router” backhaul link challenges of today and tomorrow.
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FEATURE
MAY/JUNE 2012
15
By NIR HALACHMI
Better backhaul with MPLS to the cell site
MPLS improves
backhaul-network
efficiency and
resiliency, while
enabling flexibility and service
customization.
L
AST YEAR LEFT North American
mobile operators breathless. A
wide adoption of smartphones, an
exponential increase in smart devices
(phones, tablets, game consoles, etc.), and
rapid growth in smartphone applications
compounded to make the mobile economy
very dynamic. This mobile data usage and
LTE deployment trials drove operators to
address bandwidth shortages for mobile
backhaul. More important, carriers had to
face the realization that there is a true need
for network change to support the troika
of the new mobile economy tsunami: the
convergence of mobile broadband, smartdevice growth, and applications adoption.
The first quarter of 2012 was no different,
with exciting applications like Instagram
added to Android (later acquired by
NIR HALACHMI is
product manager, mobile
backhaul products, at Telco Systems
y
. He is
responsible for the design and development of
Telco Systems’s mobile backhaul offerings focusing
on both cellular and wireless technology as well
as QoS, data security, and communications.
Facebook) or Apple announcing iPad3
with LTE connectivity. The rapid rise of
smart devices and applications acceptance has been staggering – and it’s a
global phenomenon (see Figure 1).
This rising data use has forced many
mobile operators to massively invest in the
network infrastructure to remain competitive and minimize churn, despite the
fact that they can’t link this capital investment to increased revenues. Since data
traffic is taking the higher share of the
operator networks, there is a need to
migrate mobile backhaul links to technologies that are more efficient in delivering
these services as well as supporting
the exponential growth in demand.
Change is in the air
Change is expected in almost all aspects
of the network (perhaps beside the OSS/
BSS) as a result of mobile services trends.
To address the mobile broadband arena,
carriers are adapting their networks
through a number of mechanisms.
• RAN technology is moving forward with
HSPA+, progressing to LTE and later LTE
Advanced to accommodate up to 1 Gbps
of downlink bandwidth. It is ironic that
needs are changing so fast that while
LTE is hardly commercialized, the next
“advanced” generation is already being
introduced. The fast pace of changing
technologies may cause some operators
to skip some technological generations
while others will have an even bigger
mix of technologies in their network.
• Mobile architecture is changing, with
new concepts entering the market, such
as “small cell” and “Cloud RAN.” The
Evolved Packet Core (EPC) concept
of flat, all-IP-based network also has
caught on as LTE offerings mandate
an end-to-end IP service. Such architecture will enable easier introduction
and creation of services to support
new business models, partnerships, and deployment options.
As a result of these changes, the
mobile backhaul space is evolving
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®
FEATURE
7,000
6,000
Better backhaul with MPLS
Petabytes
per month
5.5%
6.2%
7.8%
9.2%
Central and Eastern Europe
Middle East and Africa
Latin America
Japan
15.7%
North America
26.3%
Western Europe
29.3%
Asia-Pacific
5,000
4,000
3,000
2,000
1,000
0
2010
2011
2012
2013
2014
2015
FIGURE 1. The
explosion in mobile bandwidth demand is a worldwide phenomenon,
with a projected 92% CAGR from 2010 through 2015. Source: Cisco VNI Mobile, 2011
as well. But unlike the RAN and
packet core, which have been well
defined by the 3GPP standards
body, mobile backhaul traditionally
hasn’t been defined at all, leaving
operators with multiple technology options that offered different
values and disadvantages.
Fortunately, two standard bodies
have noticed this problem and taken
action. The Metro Ethernet Forum
(MEF) now offers MEF22.1 and the
new CE2.0 initiative, which promotes assured services; operations,
administration, and maintenance; and
network-to-network interconnection
for Carrier Ethernet in the role of
transport technology. Meanwhile,
the Broadband Forum has created
the TR-221 specifications for MPLS
use in mobile backhaul networks.
Mobile backhaul
requirements and options
Regardless of who provides mobile
backhaul – the mobile operator itself,
carrier’s carriers, utilities, bandwidth
wholesalers, etc. – the requirements
remain complex. For example, the
typical mobile network combines
multiple mobile technology generations like 2G, 3G, and 4G – all of
which may coexist in the same cell
or in different cells. Therefore, any
backhaul network’s technology must
offer a seamless migration path from
TDM- to packet-based transport. Since
each mobile macro cell will serve a
large number of customers and may
serve multiple base stations, operators
must implement a transport protocol(s)
that can provide high resiliency
with sub-50-msec recovery time.
While there are few technological options for mobile backhaul, there
is one common denominator: The
most viable options are packet-based.
Two options stand out: IP/MPLS and
Layer 2 Carrier Ethernet. But as the
network grows with more cell sites
(both large and small), scalability
can become a limiting factor in the
use of Layer 2 Ethernet. Therefore,
mobile backhaul providers should
consider the benefits of IP/MPLS to
the cell site for mobile backhaul.
Why extend MPLS to the cell site?
MPLS was created to combine the
best of two worlds: ATM switching
and IP routing. MPLS decouples the
MAY/JUNE 2012
16
data plane from the control plane; it is
a connection-oriented technology, so
the connection has to be established
prior to the data’s delivery. The MPLS
control plane establishes the connection by signaling through each hop
along the path. MPLS has significant
traffic engineering capabilities that
can be used to provide end-to-end
service-level-agreement assurance.
The MPLS data plane switches the
packets based on MPLS labels that are
carried inside a 32-bit MPLS header.
IP/MPLS is the de facto standard in
the core today. While most edge and
access networks are Layer 2, rapid
changes due to the dynamic nature
of mobile connectivity have forced
operators to consider extending
MPLS to the access and aggregation
layers for easier control, resiliency,
redundancy, and scalability.
MPLS at the edge of the
network for mobile backhaul
provides multiple advantages.
Maximizing scalability. MPLS
is highly scalable. The 20-bit label
enables more than one million labelswitched paths (LSPs) per node. With
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FEATURE
each node changing the label and
reusing labels, practically infinite
LSPs can be supported. By using
virtual private wire/line services
(VPWS/VPLS), such a network can
support thousands of customers
and each customer can have a different logical topology. Hierarchical
VPLS (H-VPLS) technology further
increases scalability by segmenting the network into several fully
meshed partitions, each concentrating into the VPLS hub (see Figure 2).
In contrast, Ethernet’s 12-bit
VLAN tags support only 4,000
VLANs per switch. VLAN stacking
(Q-in-Q) enables 4,000 customer VLANs to be carried in 4,000
provider VLANs. Since each customer is likely to use multiple VLAN
IDs, the number of customers that
can be supported is quite limited.
Dynamic path creation. As
mentioned, MPLS is a connectionoriented technology where control
plane protocols (namely LDP and
RSVP variants) handle path creation,
starting from the source label edge
router (LER), traversing the label
switch routers all the way through
the destination LER. These protocols base their path creation on
the dynamic routing information
exchanged between peers. The
dynamic nature of MPLS minimizes
service creation time while increasing
VPLS network
MTU
Hierarchical VPLS network
MTU
PE
MTU
MTU
PE
Spoke
VCs
PE
CE
VLANs,
routers
stacked VLANs,
MTU
PE or VC labels
MTU
MTU
PE
MTU
MTU
FIGURE 2. Virtual
MTU
MTU
PE
PE
MTU
Hub
VCs
PE
MTU
MTU
private line services (VPLS) network vs. hierarchical VPLS network.
network scalability since most of
the work is done by dynamic protocols. When path creation can be
accomplished by configuring only
the end devices, manageability of
the network becomes even easier.
Traffic engineering capabilities. MPLS provides strong traffic
engineering capabilities embedded in the MPLS control protocols.
The control plane can check and
reserve bandwidth when establishing a path only after assuring
the required committed information rate is available throughout
the proposed path. The control
plane also can mandate that traffic
pass through specific nodes using
strict rules or provide other protocols full dynamic control to ease
the operational management of
the network as changes occur.
Support of TDM and other legacy
services. Because it is essentially a
tunneling protocol, MPLS supports
the transport of any service available
today – TDM, Ethernet, Frame Relay,
ATM, IP, etc. These services and
protocols are encapsulated with MPLS
_______________________
____________
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®
FEATURE
Network edge
(aggregation and demarcation)
Network core
AGN
SN
ABR
ABR
AGN
AGN
AN
ABR
ABR
AGN
AGN
AN
AN
AGN
MPLS domain
FIGURE 3. A
“seamless” MPLS architecture decouples the service layer from the
transport layer. This decoupling increases the flexibility to define and introduce new
services by enabling service nodes to be placed at optimal locations in the network.
labels, then switched to the destination, which may be another customer
site or a service within the provider network. Taking into account
the very strict timing requirements
of TDM-based mobile technologies,
traffic engineering can be used to
assure the proper delivery of these
services concurrently, combined
with other less sensitive data services. MPLS with traffic engineering
thus can guarantee dedicated
bandwidth for the TDM-based mobile
elements still in service to minimize
the dreaded “iPhone dropped call”
problems when bandwidth-hungry
applications usurp the link capacity.
Designing the network for
resiliency. As each cell site
supports a large amount of end
users, downtime translates into large
revenue loss. Redundancy therefore
must be part of the network design
from the cell site, across the access
and aggregation networks, and
through the core. Primary and backup
paths using VPLS technologies enable
two levels of protection – at the tunnel
level and service level – while restricting the use of backup bandwidth
for failure scenarios only. If a failure
occurs, MPLS Fast ReRoute and
Bidirectional Forwarding Detection
provide sub-50-msec switchover, using local repair techniques
and signaling across the services
to identify and initiate rerouting.
Seamless network improves
service creation time
With the increasing deployment of
small-cell technologies, the number
of cells will grow exponentially. This
trend has caused scalability issues
and service creation challenges. The
best way to improve service creation/
delivery time is to have a network
that operates independent of the
services yet can support any servicedeployment scenario. The network
should not have transport boundaries
MAY/JUNE 2012
18
that limit access to services.
A “seamless” MPLS architecture inherently has no boundaries
and hence decouples the service
layer from the transport layer. This
decoupling increases the flexibility to
define and introduce new services by
enabling service nodes to be placed
at optimal locations in the network
rather than at the “boundary nodes.”
Although both the service and
transport layers use the same MPLS
packet formats, the difference is in
the use of the MPLS control plane.
Using the MPLS control plane end-toend enables a management system
to select the endpoints of the service
then trigger signaling to set up the
services across the network between
the endpoints (see Figure 3).
Winning move
Moving MPLS to the cell site or
aggregation point integrates access
and aggregation networks with the
core onto a single MPLS-managed
network to create significant operational advantages. This network
architecture is decoupled from
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FEATURE
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MAIN OFFICE
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Better backhaul
the service architecture and
incorporates intelligent switching
closer to the cell site to optimize
network resources and improve the
network’s overall performance in
an increasingly dynamic mobilefocused world. It also enables true
customizable services, because
quality of service parameters can
be incorporated end-to-end. MPLS
is manageable and scalable and
can support any legacy services required to enable smooth
migration to a pure IP network.
Factoring in the cost savings for
bandwidth efficiency and network
resiliency in an increasingly dynamic,
bandwidth-hungry environment,
MPLS enables additional revenues
from customized services and cost
savings through improved service
creation. Combined, all these factors
make a strong business case for
driving MPLS to the cell site.
TAIWAN
Alice Chen
886-2-2396-5128 #246
[email protected]
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Supporting Publications:
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OFC/NFOEC 2012:
The interviews
Opnext’s Bosco
on floods, 100G
u See the interview
JDSU discusses 400G, 100G
Sinclair Vass, senior director of marketing for the
CCOP unit of JDSU, talks
about what’s necessary for
400G, plus his company’s
plans for 100G as well
as agile networking.
u See the interview
ADVA talks metro 100G
Christoph Glingener, CTO of
ADVA Optical Networking,
describes why a 4×28-Gbps
approach is right for provision of
100-Gbps services in the metro.
Finisar’s Rawls talks 100G
at OFC/NFOEC 2012
Finisar Executive
Chairman Jerry Rawls
tells Lightwave’s
Stephen Hardy that
he’s not worried about
his customers turning
to in-house development of technology
— particularly 100G.
MAY/JUNE 2012
u See the interview
Before the merger with Oclaro
was announced, Opnext CEO and
President Harry Bosco reviewed the
company’s progress in overcoming
the Thai flooding, its work in
100G, and future technology.
u See the interview
Huawei offers next-gen
tech guidance
Reg Wilcox, vice president of network
marketing and product management
for Huawei Technologies USA, offers his
company’s views on 400-Gbps technology
and demand. He also describes a
petabit photonic crossconnect.
u See the interview
20
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®
FEATURE
MAY/JUNE 2012
21
By RANDY EISENACH
‘Soft decision’ FEC benefits 100G
The latest generation of forward
error correction,
soft decision FEC
offers greater
reach and other
performance
improvements.
O
NE OF THE FUNDAMENTAL
limitations in designing optical
transport networks is optical
signal-to-noise ratio (OSNR). WDM
networks must operate above their OSNR
limit to ensure error-free operation. The
OSNR limit is one of the key parameters
that determine how far a wavelength can
travel before regeneration. Depending on
whether a ROADM is designed for metro,
long-haul, or ultra-long-haul applications,
10G wavelengths can be transported
800 to 2,000 km without any unusual
measures before regeneration is required.
At data rates above 10 Gbps, however,
advanced modulation schemes are needed
to achieve similar reach. These modulation formats minimize the effects of such
optical impairments as chromatic and
polarization-mode dispersion as well as
ensure the optical signal fits within the
ITU 50-GHz grid used on modern DWDM
RANDY EISENACH is
a WDM product marketing
manager at Fujitsu
j
Network Communications Inc.
systems. The downside of these higher
data rates and advanced modulation
schemes is that they require substantially
better OSNR performance than do conventional 10-Gbps transmissions. At 100 Gbps,
the minimum OSNR required is +10 dB
higher than for 10-Gbps wavelengths.
Without some type of correction or
compensation, the OSNR requirements
would limit 100G optical transport
to extremely short distances.
Fortunately, sophisticated forward
error correction (FEC) techniques,
particularly “soft decision” FEC, can
extend the reach of 100G signals to
much longer, more usable distances.
Basics of FEC
FEC is a method of encoding a signal with
additional error detection and correction
overhead information (i.e., parity bytes)
so that optical receivers can detect and
correct errors that occur in the transmission path. FEC dramatically lowers
the bit-error rate (BER) and extends
the distances that optical signals can
be transmitted without regeneration.
There are a number of FEC algorithms
available that vary in complexity, strength,
and performance. One of the more
common and standardized first generation FECs is Reed-Solomon (255, 239).
Reed-Solomon adds slightly less than 7%
overhead for the FEC bytes and provides
about 6-dB net coding gain. In highspeed optical networks, a 6-dB gain is
a very significant performance improvement – approximately quadrupling
the distance between regenerators.
In addition to Reed-Solomon FEC, many
vendors offer stronger second generation FEC schemes as a provisionable
parameter on 10G and 40G optical
interfaces. These “ultra” FEC and “enhanced” FEC (EFEC) algorithms still use
7% overhead but implement stronger,
more complex encoding and decoding
algorithms that provide an additional 2- to
3-dB coding gain over Reed-Solomon.
While first generation Reed-Solomon
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®
FEATURE
‘Soft decision’ FEC benefits 100G
FEC and second generation EFEC
have provided substantial performance improvements for 10G and
40G wavelengths, even stronger,
more complex third generation FEC
algorithms are needed at 100G to
achieve optimal performance.
Soft decision FEC
At 100G rates, leading optical suppliers
are implementing third generation
FEC capabilities to extend performance and overall optical distances
even further. These third generation
FECs are based on even more powerful encoding and decoding algorithms,
iterative coding, and something referred to as soft decision FEC (SD-FEC).
In a hard decision FEC implementation, the decoding block makes a
firm decision based on the incoming
signal and provides a single bit of
information (a “1” or “0”) to the FEC
decoder. A signal is received and
compared to a threshold; anything
above the threshold is a “1” and
anything below the threshold is a “0.”
A soft decision decoder uses
additional data bits to provide a
finer, more granular indication of
the incoming signal. In other words,
the decoder not only determines
whether the incoming signal is a
“1” or “0” based on the threshold,
but also provides a “confidence
factor” in the decision. The confidence factor provides an indication
of how far the signal is above or
below the threshold crossing.
The use of confidence or “probability” bits along with the stronger, more
complex third generation FEC coding
algorithms enables the SD-FEC
decoder to provide 1–2 dB of additional net coding gain. In practice, a
3-bit confidence estimation normally
provides most of the theoretically
achievable performance improvement.
While 1–2-dB coding gain doesn’t
sound like much, it can translate into
a 20% to 40% improvement in overall
achievable distances, which is a very
substantial improvement at 100G.
One tradeoff with these more
advanced FECs is they require ~20%
overhead for the FEC bytes, more
than twice the ~7% overhead of first
and second generation FECs. The
higher 20% FEC overhead translates to slightly higher optical data
rates, which are already operating at the edges of currently
available technology at 100G.
Implementing 100G SD-FEC
While the mathematics behind
SD-FEC algorithms have been known
for many years and used in the
wireless industry, it is only recently
that SD-FEC has gained interest for
use on high-speed optical signals.
Numerous technology and ASIC
limitations prevented implementation
of third generation SD-FEC in optical
applications. In other words, the
semiconductors weren’t fast enough
and didn’t have enough processing power or memory to support
SD-FEC at 100G optical rates.
Take, for example, the highspeed analog-to-digital converters
(ADCs) used inside a 100G receiver. These devices operate at an
incredible 56 gigasamples per
second (Gsa/sec) and just became
generally available in 2011. SD-FEC
requires the use of even higher-speed
MAY/JUNE 2012
ADCs, operating at 63 Gsa/sec to
implement the SD-FEC processing, along with an equally fast and
powerful SD-FEC silicon implementation. Fortunately, such component
limitations are now part of the past,
meaning that SD-FEC for 100G
optical signals has become a reality.
Ready for use
As backbone speeds increase
from 10G to 100G per wavelength,
the OSNR requirements increase
by +10 dB. Without some type of
compensation or correction, 100G
optical distances would be very
limited and uneconomical.
First and second generation
FEC algorithms have been used
at both 10G and 40G to lower the
BER and improve overall distances.
Soft decision FEC is a third generation encoding algorithm that enables
longer distances and fewer regenerations on 100G optical networks.
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®
PRODUCT
SHOWCASE
These are the latest
products being featured
by Lightwave’s partners.
For more information,
click on the link at the
end of each description.
For advertising information,
contact Kathleen Skelton.
MAY/JUNE 2012
EQUIPMENT DESIGN
TEST AND MEASUREMENT
TEST AND MEASUREMENT
IntelliGain™ Optical Channel
Performance Monitors C, L, CWDM,
Wideband
Optical Wavelength Meters
Modular Multi-Terabit Solution for
Testing your Elastic Optical
Network Designs
BaySpec, Inc.
100% Made-in-theUSA, BaySpec’s Optical
Channel Monitors feature ultra fast sub-50 millisecond response, high compact size, and low power
consumption. With over 30,000 units shipped, the
ruggedized design ensures long life – now available in
reduced height option <10mm! www.bayspec.com
Bristol Instruments
Optical wavelength meters
precisely characterize the
wavelength of DWDM
lasers. Multi-wavelength
meters measure
wavelength, power, and
OSNR of DWDM signals.
High accuracy and reliability achieve the most
meaningful test results. www.bristol-inst.com
Fraunhofer Heinrich Hertz Institute
ID Photonics and Fraunhofer Heinrich Hertz
Institute launch multi-Terabit
test solution for multi-format,
flexi-grid and flexi-rate optical
transport systems up to 54 Tb/s.
www.hhi.fraunhofer.de
EQUIPMENT DESIGN
EQUIPMENT DESIGN
NETWORK DESIGN
advertisers index
LX8220
Rev2 Micro-Polisher
Hardened Passive Optical Multiplexers
BaySpec, Inc. ......................................................23
GigOptix
Krell Technologies
Lindsay Broadband
The LX8220
is a compact
40G DQPSK
optical
modulator enabling 4.5×5.5" 300-pin transponders
for metro applications. Its low drive voltage ensures
low power consumption without compromising on
optical performance.
www.gigoptix.com
2
Rev automates connector
air-polishing using a
“micro-feed” feature that
gradually lowers the ferrule
to the polishing surface
at a controlled rate. This
provides superior control
for fiber-denub and epoxy
removal. www.krelltech.com
Cube Multiplexers are a flexible plugand-play network solution that allows
service providers to cost effectively implement
point to point or ring based WDM optical networks.
WDM network cubes are modular, scalable and are
perfectly suited to transport PDH, SDH / SONET,
ETHERNET services over WWDM, CWDM and
DWDM in optical metro edge and access networks.
www.lindsaybroadbandinc.com
Bristol Instruments Inc........................................23
Centellax ..............................................................7
Corning Cable Systems .........................................9
DOW Electrical & Telecommunications...................6
Fraunhofer Heinrich Hertz Institute ......................23
GigOptix, Inc. ......................................................23
EQUIPMENT DESIGN
TEST
EQUIPMENT DESIGN
JDS Uniphase Corporation ............................... 2, 11
USB To Fiber Optic Bit-Driver
Terahertz Technologies’
FTE-7500A OTDR
Coherent 64 Gbaud Photodetector
Krell Technologies ...............................................23
Terahertz
Technologies Inc.
The CPDV1200R,
extends u²t’s family
of highly integrated
coherent products.
It consists of a
polarization diversity
network as well as
two 90° hybrids and 4 balanced photodiode pairs
monolithically integrated on InP. www.u2t.de
S.I. Tech
Supports USB 1.1 and 2.0 plug and play, multimode
or singlemode for secure communication, remote
security cameras, instruments, or other USB
devices, extended-distance. EMI/RFI immunity.
y
Order: 1.KIT #26 for
complete multimode
system. 11.3181/3182
for tempest version.
www.sitech-bitdriver.com
om
This US made OTDR has a
generous 36dB dynamic range,
a short 1 meter dead zone and
an updated easy to read menu
that offers quick navigation
between features. www.terahertztechnologies.com
u2t Photonics AG
LeCroy ..................................................................4
Lindsay Broadband .............................................23
S.I. Tech .............................................................23
Terahertz Technologies Inc. .................................23
u2t Photonics AG .................................................23
23
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ADVERTISER
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RESOURCES AND OFFERS
Centellax Inc.
100G testing solutions — the only affordable BER tester for 100G applications with a top data rate of 32 Gb/s —
enough headroom to handle virtually any level of FEC. Learn
more: http://www.centellax.com/products/testmeas/SSB32.
Centellax Inc.
High-speed analog semiconductor products for 40G and 100G
optical communications, and RF/Microwave applications. Visit
www.centellax.com for product information and datasheets.
Corning Incorporated and Lightwave
Open Nominations for the Ninth Annual
FTTXcellence Award
Award honors individual excellence in FTTx deployment
To be eligible for the award, candidates must be nominated
by a peer. Nominees may include individuals at carriers and
system operators, home developers, utilities, municipalities
or other organizations that have launched an FTTx project;
individuals at vendors or research organizations whose work
has benefited FTTx technology development; politicians or
other policymakers who have made a significant positive
impact in the regulatory or legal arena; and other deserving
individuals. CLICK HERE AND NOMINATE NOW!
Lightwave
Webcasts
This month’s spotlight webcasts:
The OFC/NFOEC Conference Wrap-up
Editorial Director and Associate Publisher Stephen Hardy will
leverage what he learned at the recent OFC/NFOEC Conference
in Los Angeles, CA, to provide an overview of the advances and
trends in optical networking technology.
Sponsored by:
Speeding Up Design & Test
of 40G & 100G Technologies
This webcast will review the following: 1. the importance of precisely
controlled frequency roll off of optical-to-electrical conversion for
standards-based performance and eye diagram test margin; 2. how
to make eye pattern measurements to predict effective bit error ratio
results without a long acquisition test time; 3. considerations for
building an efficient, high throughput electro-optical test system that
will address your current IEEE802.3ba – based standard tests today.
Sponsored by:
What Will Be Hot in Equipment Design in 2012
Dow Electrical & Telecommunications
Telecommunications cable materials provide superior environmental and physical protection, excellent surface smoothness
and outstanding processability. Click here to browse portfolio.
JDS Uniphase Corporation
Register to receive your
Free Fiber Reference Guide, Volume 2.
LeCroy Corporation
NEW WEBCAST: Coherent Demodulation: Beyond 100 Gbps
As networking standards move beyond 100 GSymbols/s new
test and measurement challenges evolve. Specializing in
presenting innovative tools to identify and debug issues during
the Silicon verification and systems development stage.
Lightwave Editorial Director and Associate Publisher Stephen Hardy
reviews his picks for the most influential technology initiatives in
equipment design for 2012.
Sponsored by:
Meeting the Challenge 100Gbps Design
at the Board Level
This webcast will identify issues for 100Gbps designers, and
highlight techniques being used to overcome hurdles, as well as the
latest test solutions available.
To view all webcasts visit
LightwaveOnline.com
Sponsored by:

metro delivery services

Transcription

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