The Top Fiber Questions blog series is dedicated to answering the most frequently asked questions in the industry. From now until the end of the year, we hope to provide great answers. Most importantly, we’d love for you to ask your fiber questions in the comments section below. MPO 360x203


I have heard about 8-fiber connectivity. I use 12-fiber MPOs (multi-fiber push). Do I need to switch?


There is a saying about how “less is more,” but as it relates to this question, the opposite is true.

The short answer is no. You do not need to switch. If managed well, a 12-fiber MPO infrastructure with more fibers per connector provides 50 percent more usable fibers per connector in the same footprint. This is valuable as evolving standards continue to use duplex fibers as connectivity options through at least 100Gbps. 

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The main reason for introduction of 8-fiber MPO connectors was to provide application support of parallel signals using eight of the available 12 fiber positions of the industry standard 12-fiber MPO connector. This application typically occurs in a QSFP (Quad Small Form-factor Pluggable) transceiver. Examples of this transceiver would be the 40GBase-SR4 or 100GBase-SR4, where four pairs of fiber deliver 10G or 25G each to achieve a channel of 40Gbps or 100Gbps. Many of the initial uses of this, for example, were for higher density connections on a switch directly to top of rack switches or to break-out to four server ports.  From an infrastructure perspective, the 8-fiber MPO connector is best suited for parallel-only applications between ports where it is a 1:1 connection. One 8-fiber connector equals one parallel port.

There are other multi-fiber connector options, such as the 12-fiber MPOs or the 24-fiber MPO, which continues to gain popularity in the market. Both are industry standard. The higher fiber count MPOs provide much more architectural flexibility and trunk efficiency compared to the 8-fiber application. For example, by combining two 12-fiber MPOs or using a single 24-fiber MPO for trunk cables, you are able to support multiple duplex, multiple parallel, or combinations of each without the need to re-cable. That flexibility enables you to cost effectively migrate applications as your network or business model evolves.

CommScope provides ultra-low loss versions of each MPO variation – 8-, 12- and 24-fiber. For guidance regarding the best values and applications for each, please refer to the “Choosing the right MPO for your data center” Application Guide.

About the Author

Ken Hall

Kenneth Hall is data center architect for North America at CommScope, responsible for technology and thought leadership, as well as high speed migration planning for enterprise and related data centers. Ken has been with CommScope and other acquired companies for 32 years in global program and project management, technical sales, marketing and industry standards. 


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2 comments for "Top Fiber Questions: Do I Need to Switch my MPOs?"
Carl Rumbolo Saturday, November 04, 2017 11:31 PM

While there is a use case for 8-fibe MPO connectors, it would not, in my experience, but a recommended practice to introduce the 8-fiber MPO into an existing cable plant built around the 12-fiber MPO. While there are solutions for converting base-12 infrastructure to a base-8 configuration using 2x3 modules, etc., those solutions introduce additional complexity that can have a significant operational impact.

Using a base-8 configuration in a greenfield plant may be a worthwhile option, however with the emergence of technologies such as SWDM4, I would question the utility of a base-8 installation.

Since the 8-fiber and 12-fiber MPO is the same physical size, and in an MPO-LC module configuration, the 12-fiber MPO allows 6 LC ports vs. 4 LC ports, in a SWDM4 solution, base-8 makes little sense. Using SWDM4 (assuming availability of the optical transceivers), the base-12 solution provides greater port density in a given volume (housing).

Given that Finisar recently announced an extended reach 100G SWDM4 transceiver with 400m reach over 2 OM5 fibers, I am not sure base-8 is really viable over the long term. (My humble opinion)

Ken Hall Monday, November 06, 2017 12:13 PM

Great points! The best utility for 8-fiber MPO is for applications where each port will use all 8 fibers. For duplex or blended applications the higher fiber count 12 or 24 fiber MPO provide greater trunk efficiencies as they accommodate multiple port options within the same size connector interface and very similar cable size.
As you noted, there are a growing number of current and planned MSA, proprietary, and standard applications that provide higher data rates and bandwidth over a single pair of fibers at longer distances. OM5 provides that greater value for multimode and multi-wavelength applications, for example.

Data center operators have choices to make as their networks migrate. Designing in a thoughtful, cost-effective cabling infrastructure now will optimize flexibility for change between duplex and parallel as their business models evolve!

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