With the emerging high-speed network standards and rapidly advancing technology, fiber optic network is driven to meet the growing demand for faster access to larger volumes of data.

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FS.COM White Paper | 100G Direct and Breakout Cabling Solutions
With the emerging high-speed network standards and rapidly advancing technology, fiber optic
network is driven to meet the growing demand for faster access to larger volumes of data. Although
10G/40G Ethernet becomes the mainstream of telecommunication market nowadays, organizations
of all sizes still need to be prepared to integrate speeds of 100G and beyond. For data center
networking, users can choose different solutions based on the different transmission distance need.
In general, there are two kinds of 100G fiber optic solutions: direct cabling and breakout cabling. It
is essential for users to understand the detailed information of each type of solution in order to
select the one that meets their current and future connectivity needs.
How 100G Optics Develop
After the IEEE completing the certification of the first 100G standard for Ethernet networks, the
transceiver industry launched a new type of form factors for 100G connectivity—CFP ("C" for 100,
and FP for Form factor Pluggable). Compared to the most popular 40G QSFP, the size of CFP
transceiver is huge. And most CFP implementations doubled the power consumption per bit.
Furthermore, the price per bit increased by a factor of ten. These disadvantages becomes the main
obstacles of the popularity of 100G CFP transceivers.
The next version of 100G form factors is the CFP2, CFP4, and the CPAK that are improved upon the
CFP. But when compared to the popular 10G SFP+ and 40G QSFP+, none of these new members of
the CFP family improved density, power consumption, or cost. The following image shows the size
comparison between CFP2, CFP4 and QSFP28 modules.
100G Direct and
Breakout Cabling
Solutions

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FS.COM White Paper | 100G Direct and Breakout Cabling Solutions
Then here came the 100G QSFP28. The QSFP28 is the exact same footprint as the 40G QSFP+. The
100G QSFP28 is implemented with four 25-Gbps lanes, Just as the 40G QSFP+ is implemented using
four 10-Gbps lanes. In all QSFP versions, both the electrical lanes and the optical lanes operate at
the same speed, eliminating the costly gearbox found in CFP, CFP2, and the CPAK. The 100G QSFP28
makes it as easy to deploy 100G networks as 10G networks. When compared to any of the other
alternatives, 100G QSFP28 increases density and decreases power and price per bit. That’s why it is
fast becoming the universal data center form factor. The following part will move on to talk about
the 100G optic cabling solutions.
100G Direct Cabling Solutions
QSFP28 transceiver utilizes either fiber or copper media to achieve 100GbE communication in each
direction. This transceiver has 4 individual 25GbE lanes which can be used together to achieve
100GbE throughput or separately as 4 individual 25GbE connections (using 4 SFP28 modules).
For 100G short-reach direct cabling within 100m, 100GBASE-SR4 QSFP28 optical module and 100G
QSFP28 cable are good choice. Just from the table list of FS.COM 100G optical modules and cables,
we know that 100GBASE-SR4 QSFP28 modules can support up to 100 m on OM4 12 fiber
multimode MTP cable. And 100G QSFP28 to QSFP28 direct attach copper cable can support up to
5m and 100G QSFP28 to QSFP28 active optical cable can support up to 10m. Figure 2 describes a
100G direct cabling with the use of QSFP28 to QSFP28 DAC and AOC cables.

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FS.COM White Paper | 100G Direct and Breakout Cabling Solutions
For 100G long-haul direct cabling, like 10km, both 100GBASE-LR4 QSFP28 optical module and
100GBASE-LR4 CFP4 transceiver can support up to 10km on single-mode LC patch cables. For longer
100G direct cabling above 10km, the 100GBASE-ER4 CFP is the ideal choice as their transmission
distances support up to 40 km.
100G Breakout Cabling Solutions
A breakout cable is a multi-strand cable, typically custom-made, which is divided into multiple
duplex cables. For instance, a 40G breakout cable has four individual 10G duplex cables totaling
eight strands, while a 100G breakout cable has 10 duplex cables and 20 strands. Figure 3 displays a
simple 100G connectivity with 100GBASE-SR4 QSFP28 and QSFP28 to 4SFP28 breakout cables.
Between the 100G optical module and 25G optical modules, there always uses the breakout cables
connected the two kinds of optical modules, and the common cable solutions are 100G QSFP28 to
4SFP28 Breakout AOC cables or 100G QSFP28 to 4x 25G SFP28 Breakout Direct Attach Passive
Copper Cables.
The commonly used 100G breakout cabling solutions is 100G QSFP28 to 4SFP28 DAC. It’s easy to
understand how this type of cable function. Just as the QSFP+ breakout cable, the 40GBASE-SR4
QSFP+ optical module at the one end can be connected to 4x10GBASE-SR SFP+ optical modules at
the other end.

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FS.COM White Paper | 100G Direct and Breakout Cabling Solutions
Conclusion
As IT infrastructures are planning to migrate to 100G data rate, network designers must carefully
weigh alternative implementations of such links. With a variety of fibers already deployed, it is
important to understand the interoperability of new optics with existing fibers. And for 100G
deployment, you are supposed to understand the benefits and challenges of each type of the fiber
optic solutions before taking an action. FS.COM’s 100G FHD series covers a full range of 100G
optical transceivers and cables, like CFP, CFP2, CFP4, QSFP28, as well as 100G QSFP28 to QSFP28
DAC, 100G QSFP28 to 4SFP28 DAC. Besides the above products, 100G FHD Fiber Enclosures, 100G
FHD MTP Modular Cassettes, 100G 160 Fiber 2U Panels and 100G CFP SR10 Cables are also
provided. If you want to know more about our products, please contact us directly.

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FS.COM White Paper | 100G Direct and Breakout Cabling Solutions
Contact Us
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Tel: +44 (020) 3287 6810
Notice: This document is for informational purposes only and does not set forth any warranty, expressed or
implied, concerning any equipment, equipment features, or service offered or to be offered by FS.COM.
FS.COM reserves the right to make changes to this document at any time, without notice, and assumes no
responsibility for its use. This information document describes features that may not be currently available.
Contact a FS.COM sales team for information on feature and product availability.
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