With many of today’s data centers now consisting of flattened architectures that deploy end of row (EoR) and middle of row (MoR) designs where 10GBASE-T access switches connect to servers within the row, horizontal cabling lengths have become shorter than ever.
The channel length between an access switch and a server in a neighboring cabinet can be as short as three meters for a two-connector channel. Since it is actually more difficult to meet category 6A performance parameters for 10GBASE-T over a shorter distance, it’s important to make sure that your cabling solutions are up to par. If not, you might find yourself having to deal with excess cabling slack and potential airflow concerns.
For popular EoR and MoR modular designs that use standardized configurations for server cabinets and enable a predictable “pay as you grow” methodology, many data center managers are finding that pre-terminated copper solutions are ideal for the fixed portion of the channel—from the patch panels at the access switch to the patch panels in the server cabinets. They require less skill and labor to deploy, allowing installations and upgrades in a fraction of the time required for field terminations.
Since the main reason for pre-terminated copper cabling is to speed deployment, it only makes sense to look for solutions that offer the fastest and easiest installation. Intuitiveness of the plug-and-play method, ease of routing and cable management all impact deployment speed.
For example, Belden’s 10GX Pre-Terminated Cabling System features assemblies that are terminated with a plug interface that simply plugs into the back of the patch panels rather than needing to individually snap jacks or cassettes into the patch panel.
The plug interface itself is quite a bit smaller than jacks or cassettes, making it easier to pull and route the cables in a high-density environment. In general, plugs are also more robust than jacks due to the integrated strain relief boot that protects the conductors and prevents movement at the point of termination.
The size of the cable bundle itself is another consideration. Pre-terminated solutions that use more than a 6-cable bundle typically have to be staggered to ensure that each cable can reach its specific patch panel port. This requires more careful upfront planning and ordering. Look for smaller bundles of cables that plug in the back of patch panels in a straight alignment.
While speed and ease of installation is a key consideration when selecting copper pre-term, performance is by far the most critical—especially in today’s bandwidth-intensive applications that simply can’t tolerate bottlenecks.
In MoR and EoR designs that feature much shorter horizontal links within the row, pair-to-pair near-end crosstalk (NEXT), return loss and power sum alien near-end crosstalk (PSANEXT) are more impacted at the higher frequencies of 10GBASE-T by connectors located in close proximity to the equipment.
Many data center managers prefer to deploy a cross-connect at the access switch to keep switch ports secure and enable manageability. This results in a 3-connector channel. For even more manageability, some use a zone distribution approach with yet another patch panel and a 4-connector channel. Unfortunately, the impact on NEXT, return loss and PSANEXT is even greater for a short channel with more than 2 connectors.
Some category 6A pre-terminated solutions may not meet the performance requirements for 3- or 4-connector channels when the distance is less than 15 meters. This can limit flexibility in EoR and MoR designs or result in excess slack that can block airflow in cabinets or under the floor. Imagine having to deal with a 15-meter cable assembly when you only need to go a few meters from a patch panel in the switch cabinet to a patch panel in an adjacent server cabinet.
The RJ-45 couplers used in Belden’s 10GX Pre-Terminated Cabling System are designed with performance that eliminates short length restrictions, enabling the use of flexible EoR and MoR multi-connector channels with a distance as short as 2 meters between connectors. For more information about Belden’s short length abilities, check out the Short is Tough white paper.
Learn more about Belden’s innovative 10GX Per-Terminated Cabling System for easier, better performing 10GBASE-T horizontal links in the data center—short or long.
Mike Salvador is a 28-year industry veteran, living the challenge of operating efficient data centers, optimizing the performance of network devices and delivering highly available, highly agile, low-risk data centers. Mike served as Belden’s technical solutions manager from 2012 to 2015.