Fiber Optic Cabinets, Cables, Pedestals and Terminals

The stock car racing season is approaching fast and much like communication networks – it’s a balance of speed and distance with each track posing different challenges to maintain your speed without crashing before the finish line. The communications cabling field is full of articles and presentations about souping up your lower speed network to Category 8 cable or multimode fiber (MMF) for a higher speed network, whether it is 1 Gb/s to 10Gb/s up thru 100Gb/s. I spend a good deal of time reading these publications and listening to presentations at BICSI events, and end up with the same conclusion: Why build a restrictor plate in your network?

I am an Application Engineer and a BICSI Registered Communications Distribution Designer (RCDD), but while with another company back in 2012 and vetting out vendors for high density 10Gb/s with a path to 100Gb/s core, aggregation and edge one, a vendor demonstrated their 400Gb/s capability for an underlying Optical Transport Network. The connecting medium throughout both networks would be singlemode fiber. Multimode fiber was never really in the race and Cat cable didn’t even qualify. Currently, as an application engineer traveling and talking with data center managers, network managers and designers, I see that many, just now, are understanding the limitations of copper Category cabling and multimode fiber in the face of increasing bandwidth demands and distances. The simple truth is singlemode fiber is the only full throttle solution, the hot setup to keep you in front of the pack.

Let’s say you are designing a campus network and determining what medium to specify; Category 5e/6/6a/now Cat 8 cable, multimode fiber or singlemode fiber. Personally, I would never recommend or design around twisted copper pairs, unless it was 2002. Today we have video chat, countless remote devices, Smart TVs, 4K and soon 8K (then 16K) video resolution. Copper Category cable is a patch cord in 2017 with no place in the distribution pathways. 

What about Power over Twisted Pair? There are other options – just ask your Optical Line Terminal (OLT)/Passive Optical Network (PON) equipment representative. Passive Optical LAN is continuing to gain ground over traditional Ethernet LAN. Take in consideration the sheer size and cumulative weight of a copper based medium…it’s like racing in a garbage truck. The new Cat 8 cable is 10% larger in diameter than Cat 6a. Check out the speed and distance chart and size comparison below. By simplifying the design, optical fiber cabling is mean, lean and built for speed.

table 1


You may think multimode fiber is a viable option, and it is, IF you want to limit your speed and distance. The demand on your networks are not slowing down and the distance to edge is being pushed farther out to support the increasing number of devices and services. Multimode restricts your network and increases the engineering effort to measure distances to the meter. You are creating unnecessary pit stops. Why put a governor on your network speed?

In the data center, you could be utilizing a multimode jumper intra-cabinet between the switch and the servers or between line-ups. This setup is sustainable for now with the new multimode Short Wavelength Division Multiplexing optics (SWDM) and OM5 fiber or with OM4 fiber utilizing 4 TX/RX channels on a MPO/MTP jumper. But, we all know that 400Gb/s speeds and greater are coming soon. If you have adopted OM4/OM5 in the permanent links, do you want to upgrade your fiber cabling again in 3 to 5 years to accommodate terabit speeds? OM5 does not give greater distance versus OM4. OM5 allows for multiplexing four wavelengths on an individual multimode fiber. This means a new color (lime green), a new pluggable and new technology, which ultimately means increased cost. Singlemode fiber will support virtually any speed for kilometers while multimode fiber only supports certain speeds for meters. MMF is like putting soft tires on, yeah you’ll go fast in the corners but only a few laps for a limited distance.

table 2

Finally, there is singlemode fiber (SMF). Singlemode distances and speeds are basically limited only by the active gear you choose. The cable is less expensive than multimode fiber. Choosing a singlemode fiber allows option for GPON, Active Ethernet, DWDM, CWDM and traditional Ethernet. Do you want to let the cable in your network be a restrictor plate limiting the type of services that can be deployed over it?


You have likely heard that singlemode pluggables are much more expensive, but that is not necessarily true today. The gap has narrowed and much depends on if you are deploying the OEM’s pluggable, a secondary vendors or using fixed vs. tunable. Still concerned about cost? Take into consideration the cost of migrating off or removing a lesser cabling network 3 to 5 years down the road into your business case. Labor to remove an outdated medium is the true expense!

Clearfield can provide a “splash-n-go” of Category cable and put on some multimode fiber “sticky tires” for a green/white finish, OR­ supply the complete hot setup of singlemode fiber that allows you to lead from start to finish. The options for building a network will come at you faster than the debris from the big one at Daytona, and my colleagues and I at Clearfield are here to be your spotters through the chaos.

Marty Adkins, Application Engineer