Know these facts no one would tell you about 10G to 40G migration in data centers

10G to 40G has become the hot topic of discussion since the ratification of the IEEE 802.3ba standard in 2010. There is a flowery picture painted in the minds of the end consumers about how the speeds will reach a revolutionary peak and at the back end, specialists are banking on the solutions that may make the migration process nothing more than plug-and-play. But, are we missing something important amongst all the hype? What is going to happen to copper cabling solutions? How intra-rack and inter-rack connections are going to transform? What will happen to various losses (return or insertion) that are unavoidable part of a fiber optics set-up? These are a few questions that need a tangible explanation and are surely going to give way to the clearer picture of the set-up you may expect in a futuristic data center supporting 40G connectivity.

Data centers, these days, are more like almost active kind of environments and these can never be put on a standby mode. So, the upgradation or expansion process is to be carried out in an incremental style so that there is always a scope for stepping down to the original set-up in case of an unforeseen failure. To begin with, direct attach cables, use of multi-mode or single mode and copper vs. fiber are some of the points of discussion that do need attention while looking at the bigger picture involving switches and transceivers. So, here are some of the much needed points of insight that deliver better picture of what a 40G data center is going to offer to the user in terms of structure and processes.

AOCs are certainly a must-have but do understand the need to pick the best

Active optical cable is designed to support 40G connectivity in the data centers supplementing the data reach of 5 meters or around. To make the introduction of an AOC more viable one, the active optical cable assembly is designed to work with an array of protocols that are widely used in intra-rack, inter-rack or inter-building applications. The only reason why AOC were brought into being was to provide the users a better solution than copper cables that had their own problems. But, an AOC can serve the purpose to the fullest satisfaction only if it does not involve mammoth cost and deliver smaller carbon footprint. The perfect answer to these requirements lies in low-power active optical cable assembly.

Optical fiber communication needs cannot be fulfilled by AOCs if these are not fully reliable. The requirement of data centers to remain omniscient leaves no room for errors and failures are a big no-no. Thus, just having a 40G Active Optical Cable solely in not enough; the solution should be bought only from the sellers who test their products thoroughly. To reduce the cooling need and also to ensure low cost, it is advisable to pick only low-power 40G AOC solution.

Some areas of data centers still have scope for the use of copper cables

Too much propagation about the use of optical cables has led many users to believe that the copper cable assemblies are totally obsolete. However, the truth is that copper cabling solutions are still better alternative to passive optical cable in some areas such as top-of-the-rack applications. The passive copper cables help cut the cost and support 4x10G channel applications. Thus, you can still ask for Cozlink Twinax copper cables if the data reach requirement is not more than some 7m or so.

The newer product in copper cables is ribbon style cable that offers better alternative to conventional round cables. While the round cables come with the restriction of bending as too much bending may distort their physical and functional aspects, the ribbon style cable is provided with shield structure that offers connectivity in both horizontal and vertical directions. The shield design is able to combat the resonance effect appreciably even when folded or used in bent condition.

Futuristic data centers cannot do with LC duplex connectors

Data centers moving to 40G connectivity will have to abandon the LC connectors completely. The standards meted out in IEEE 802.3ba promote the use of MTP/MPO connectors that support the conglomeration of cables required for achieving the 40G data speed. Presently, LC duplex connectors can provide slots for only two fibers that produce speed only to the maximum of 15G. But, with MPO connectors around it will be easy to achieve a 72-fiber configuration in single connector.

MTP connectors of the current generation are compatible with cassette-based physical layer installations. This is a connector interface meant only for duplex connectivity solutions delivering 10G speeds. The next in the line is MTP connector that would be able to support 40G transceiver interface. As of now, MPO plug-and-play system is in fashion that involves integrating an MPO connector into the cassette. The 12-fiber trunk optical cable creates Rx/Tx link on which 10G connections are established. And the remaining 4 fibers are kept dark, which may be used for some other connectivity purposes.


The data centers supporting 40G data speeds will be a wise and cost-effective combination of structure and method. Direct attach cable (DAC) may not serve the purpose owing to the accelerated effect produced in a point-to-point cabling method. Also, the upgradation/movement is not so smooth. So, structured cables will occupy the most of the data center spaces owing to their flexibility and ease of use.

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