Application Notes
24-Fiber Trunking and
Interconnect Solution
The Right Migration Path to
40/100 Gig
For more information, visit commscope.com
What the Standards Say
Video views on YouTube climbed from 100 million views per day in 2006
to well over 4 billion views per day in 2012. Song downloads on iTunes
increased from 5 billion in 2008 to more than 16 billion by 2012. Average
smartphone usage tripled in 2011*, and forecasts estimate that by the end
of 2012, the number of mobile-connected devices will exceed the number of
people on earth. Over the next two years, our world will create, process and
store more data than in the entire history of humankind.
In 2002, the IEEE ratified the 802.3ae standard for 10 GbE over fiber
using duplex fiber links and vertical cavity surface emitting laser (VCSEL)
transceivers. Most 10 GbE applications use duplex LC style connectors
where one fiber transmits and the other receives. Standards efforts aimed
at finding a cost-effective method to support next-generation speeds of
40 and 100 Gbps, and in 2010, the IEEE ratified the 802.3ba standard
for 40 and 100 GbE. Similar to how transportation highways are scaled to
support increased traffic with multiple lanes at the same speed, the 40 and
100 GbE standards use parallel optics, or multiple lanes of fiber transmitting
at the same speed. Running 40 GbE requires 8 fibers, with 4 fibers each
transmitting at 10 Gbps and 4 fibers each receiving at 10 Gbps. Running
100 GbE requires a total of 20 fibers, with 10 transmitting at 10 Gbps and
10 receiving at 10 Gbps. Both scenarios call for using high-density multi-fiber
MPO style connectors.
In conjunction with the media demands of today’s Internet and the mobile
network boom, the amount of data transmitted at the enterprise business
level is also rapidly climbing as networks need to support more devices and
advanced applications than ever before. Cisco Visual Networking Index*
forecasts that business data traffic will grow 22% between 2011 and 2016,
with business video conferencing alone increasing sixfold. In fact, it is
estimated that by 2016, the gigabyte equivalent of all the movies ever made
will cross global IP-based networks every three minutes, with North America
accounting for 3.3 exabytes per month, or more than 3 billion gigabytes.
Data centers are at the heart of the tremendous amount of business data
needing to be transmitted, processed and stored. In the data center, fiber
optic links are vital for providing the bandwidth and speed needed to
transmit huge amounts of data to and from a large number of sources. More
bandwidth is also needed to support the use of virtualization that consolidates
multiple computer platforms onto single physical servers to reduce the amount
of equipment and improve space utilization. As data center managers strive
to provide the bandwidth they need, transmission speeds at core switches
are increasing and backbone infrastructures are experiencing a significant
upsurge in the amount of fiber optic cabling. Typical transmission speeds in
the data center are beginning to increase beyond 10 gigabit per second
(Gbps). In 2010, the IEEE ratified the 40 and 100 gigabit Ethernet (GbE)
standard, and leading switch manufacturers are already offering 40 GbE
blades and more than 25% of data centers have implemented these next
generation speeds. It is anticipated that by the end of 2013, nearly half of
all data centers will follow suit. Today’s enterprise businesses are therefore
seeking the most effective method to migrate from current 10GbE data center
applications to 40/100 GbE in the near future.
For 40 GbE, a 12-fiber MPO connector is used. Because only 8 optical
fibers are required, typical 40 GbE applications use only the 4 left and
4 right optical fibers of the 12-fiber MPO connector, while the inner 4
optical fibers are left unused as shown in Figure 1.
To run 100 GbE, two 12-fiber MPO connectors can be used—one
transmitting 10 Gbps on 10 fibers and the other receiving 10 Gbps on
10 fibers. However, the recommended method for 100 GbE is to use
a 24-fiber MPO style connector with the 20 fibers in the middle of the
connector transmitting and receiving at 10 Gbps and the 2 top and
bottom fibers on the left and right unused as shown in Figure 2.
CommScope’s data center fiber trunking and interconnect solution allows
enterprise data center managers to effectively migrate from 10 GbE to
40/100 GbE. By leveraging 24-fiber trunk cable technology, CommScope
offers the right 10-40-100 GbE migration path with:
• Support for 10, 40 and 100 GbE
• Maximum utilization of deployed fibers
• Space savings and reduced congestion
• Better airflow and energy efficiency
Figure 1: For typical 40 GbE
applications, the 4 right and 4 left
fibers of a 12-fiber MPO connector are
used for transmit and receive while the
inner 4 fibers are left unused.
• Increased density in fiber panels
• Easier, cost-effective migration scheme
• Overall better return on investment
Figure 2: For 100 GbE applications,
the middle 20 fibers are used for
transmitting and receiving 10 Gbps
while the 2 fibers on the left and 2
fibers on the right are left unused.
To keep costs down, the objective of the IEEE was to leverage existing
10 GbE VCSELs and OM3/OM4 multimode fiber. The standards therefore
relaxed transceiver requirements, allowing both 40 and 100 GbE to use
arrayed transceivers containing either 4 or 10 VCSELs and detectors,
accordingly. This prevented the cost of 40 GbE transceivers being four
* ”Global Mobile Data Traffic Forecast Update, 2011- 2016,”
Cisco Visual Networking Index, February 2012.
2
For more information, visit commscope.com
times that of existing 10GbE transceivers for 40 GbE, or 10 times the cost
of existing 10 GbE transceivers for 100 GbE. According to IEEE 802.3ba
standard, multimode optical fiber supports both 40 and 100 GbE over
link lengths up to 150 meters when using OM4 optical fiber and up to
100 meters when using OM3 optical fiber.
cable provides a single 100 GbE link. Why is this more advantageous than
using 12-fiber trunk cables? It all comes down to a better return on investment
and reduced future operating and capital expense.
Maximum Fiber Utilization
As mentioned previously, 40 GbE uses eight fibers of a 12-fiber MPO
connector, leaving four fibers unused. When using a 12-fiber trunk cable,
those same four fibers are unused. For example, three 40 GbE links using
three separate 12-fiber trunk cables would result in a total of 12 unused fibers,
or four fibers unused for each trunk.
It is important to note that singlemode fiber can also be used for running
40 and 100 GbE to much greater distances using wavelength division
multiplexing (WDM). While this is ideal for longer reach applications
like long campus backbones, metropolitan area networks and other longhaul applications, the finer tolerances of singlemode fiber components
and optoelectronics used for sending and receiving over singlemode are
much more expensive and are therefore not feasible for most data center
applications of less than 150 meters. Copper twinax cable is also capable of
supporting 40 and 100 GbE but only to distances of 7 meters. According to
a data center study conducted by Building Services Research and Information
Association (BSRIA) that surveyed 335 respondents in six countries, 29% of
respondents plan to use OM3/OM4 multimode fiber for 40 GbE and 41%
plan to use OM3/OM4 for 100 GbE. On the other hand, only 11% plan
to use copper twinax for both 40 and 100 GbE applications. Table 1 shows
the 40 and 100 GbE standards with their associated cabling media and
link lengths.
Standard
Cable Medium
Link Length
40GBASE-CR4
Copper Twinax
7m
40GBASE-SR4
Multimode Fiber
100 m OM3
150 m OM4
40GBASE-LR4
Singlemode Fiber
10 km
100GBASE-CR10
Copper Twinax
7m
100GBASE-SR10
Multimode Fiber
100 m OM3
150 m OM4
100GBASE-LR4
Singlemode Fiber
10 km
100GBASE-ER4
Singlemode Fiber
40 km
With the use of 24-fiber trunk cables, data center managers actually get
to use all the fiber and leverage their complete investment. Running three
40 GbE links over a single 24-fiber trunk cable uses all 24 fibers of the trunk
cable. This recoups 33% of the fibers that would be lost with 12-fiber trunk
cables, providing a much better return on investment. At 100 GbE which
requires 20 fibers, a total of four fibers are left unused when using either two
12-fiber trunk cables or when using a single 24-fiber trunk cable. However,
additional benefits come into play for 100 GbE and 12-fiber trunk cables are
not the recommended configuration for 100 GbE. Figure 3 shows the ratio of
24-fiber trunk cables to corresponding connector types for each application.
Figure 3: A single 24-fiber trunk cable provides twelve 10 GbE links, three 40
GbE links and a single 100 GbE link.
Table 1: IEEE standards for 40 and 100 GbE
Reduced Cable Congestion
24 — The Right Migration Path
Another benefit to using 24-fiber trunk cables is less cable congestion. Space
is at a premium in the data center, and congested cable pathways make
cable management more difficult and impede proper airflow needed to
maintain efficient cooling and subsequent energy efficiency. CommScope’s
24-fiber trunk cables are only appreciably larger than 12-fiber trunk cables
at 3.8 mm in diameter, compared to 3 mm. That means the 24-fiber trunk
cables provide twice the amount of fiber in less than 21% more space. For a
40 GbE application, it takes three 12-fiber trunk cables to provide the same
number of links as a single 24-fiber trunk cable—or about 1-1/2 times more
pathway space (see Figure 4).
Knowing that 40 and 100 GbE are just around the corner, and already
a reality for some, many data center managers are striving to determine
which physical layer solution will support 10 GbE today while providing
the best, most effective migration path to 40 and 100 GbE. While many
solutions on the market recommend the use of 12-fiber multimode trunk cables
between core switches and the equipment distribution area in the data center,
CommScope recommends and offers a better standards-based migration path
with the use of 24-fiber trunk cables.
The use of 24-fiber trunk cables between switch panels and equipment is a
common-sense approach. In this scenario, 24-fiber trunk cables with
24-fiber MPOs on both ends are used to connect from the back of the switch
panel to the equipment distribution area. For 10 GbE applications, each of
the 24 fibers can be used to transmit 10 Gbps, for a total of 12 links. For
40 GbE applications, which requires 8 fibers (4 transmitting and 4 receiving),
a 24-fiber trunk cable provides a total of three 40 GbE links. For 100 GbE,
which requires 20 fibers (10 transmitting and 10 receiving), a 24-fiber trunk
6.0 mm
3 x 12 F Trunks
3.8 mm
1 x 24 F Trunk
Figure 4: 24-fiber trunk cables provide twice the fiber in less than
21% more space
3
For more information, visit commscope.com
Increased Fiber Density
Because 24-fiber MPO connectors offer a small footprint, they can ultimately
provide increased density in fiber panels at the switch location. With today’s
large core switches occupying upwards of 1/3 of an entire rack, density in
fiber switch panels is critical.
CommScope’s data center fiber trunking and interconnect solution consists of
the 24-fiber trunk cables from the back of the fiber panels to the equipment
distribution area. With the rack or cabinet, hydra cables plug into the
24-fiber MPO ports on the front of the fiber panel and connect to individual
switch ports. Hydra cables feature a single 24-fiber MPO connector on
one end and either 12 duplex LC connectors on the other end for 10 GbE
applications, 12-fiber MPO connectors for 40 GbE or a 24-fiber MPO
connector for 100 GbE. With a single 1RU fiber panel able to provide a
total of 32 MPO adaptors, the density for 10 GbE applications is 384 ports
in a 1RU (duplex LC connectors) and 96 40 GbE ports in a 1 RU (12-fiber
MPOs). Table 2 demonstrates the various densities provided by CommScope’s
data center fiber trunking and interconnect solution for 10 GbE, 40 GbE and
100 GbE applications.
Figure 5: Hydra cable with
a 24-fiber MPO on one end
and 12 duplex LCs on the
other end
Application
Hydra Cable
Configuration
24-fiber MPO
Panel Ports
1 RU Port
Density
4 RU Port
Density
10 GbE
24 MPO to
12 duplex LCs
32/blade
384
1536
40 GbE
24 MPO to 2
12 MPOs
32/blade
96
384
100 GbE
24 MPO to 24
MPO
32/blade
32
128
Table 2: CommScope’s fiber panel port densities
Easier, Cost-effective Migration Path
CommScope’s data center fiber trunking and interconnect solution offers a
simple and cost effective migration path from 10 GbE to 40 and 100 GbE,
providing future proofing for three generations of active equipment. With
24-fiber trunk cables effectively supporting all three applications, there is
no need to recable the pathways from the back of the switch panel to the
equipment distribution area—all of that cabling remains permanent and
never has to be touched as shown in Figure 6. That means that data center
managers can easily migrate to higher speeds, with less time and complexity.
With 24-fiber trunk cables that offer guaranteed performance for 10, 40 and
100 GbE, upgrading the cabling infrastructure is as simple as upgrading the
hydra cables or cassettes and patch cords to the equipment.
or
100G*
100G†
100G†
*100G implemented as 4x25G
†100G implemented as 10x10G
Figure 6: With CommScope’s data center fiber trunking and interconnect solution,
24-fiber trunk cables remain permanent for 10, 40 and 100 GbE applications.
An Overall Better Return on Investment
CommScope’s data center fiber trunking and interconnect solution is ideal for
a medium-to-large data center customers and markets, from healthcare and
finance, to broadcasting and government—essentially anyone that foresees
the need to update from 10 to 40/100 GbE in the future. With guaranteed
support for all three applications, the ability to use all the fiber deployed,
reduced cable congestion and better airflow, higher port density in fiber
panels, and an easy migration scheme, CommScope’s data center fiber
trunking and interconnect solution with 24-fiber trunk cables offers lower
future capital and operating expense.
Unlike other solutions on the market that leave one-third of the fiber investment
stranded, impede airflow with over-congested pathways, and provide
inadequate port densities, CommScope’s data center fiber trunking and
interconnect solution helps data center managers effectively and efficiently
support today’s high-speed requirements. With permanent 24-fiber trunk
cables that eliminate the need for complete and complex reconfigurations all
the way from the switch to the equipment, CommScope’s data center fiber
trunking and interconnect solution offers an easy, cost-effective method for
upgrading from 10 GbE to 40 and 100 GbE.
As the amount of data being created, processed and stored reaches an all
time high, data center managers need to prepare themselves today to migrate
to 40/100 GbE tomorrow. With increasing concerns about the cost to
upgrade and the complexity involved, data center managers need a solution
that simplifies the process and provides better return on investment, while
meeting both current and future current needs. CommScope’s data center fiber
trunking and interconnect solution is the right migration path to 40/100 GbE.
www.commscope.com
Visit our website or contact your local CommScope representative for more information.
© 2015 CommScope, Inc. All rights reserved.
All trademarks identified by ® or ™ are registered trademarks or trademarks, respectively, of CommScope, Inc.
This document is for planning purposes only and is not intended to modify or supplement any specifications or warranties relating to CommScope products or services.
AN-314288.3-AE (12/15)
or
100G*