OM1? OM3? RCD2? What do these cryptic fiber optic acronyms mean anyways? In this case the first two are different grades of glass, the third being a horrible joke that got your attention. Regardless, I’d like to take a minute to view the world of fiber from a strangers point of view.
Fiber optic cable: a wave of the future in the world of communications (and a slight trip to the past in some cases). Simply put it’s just a piece of glass that’s drawn extremely thin with some “special” ingredients added to the center, aka core. Light enters one end and on a good day, it will come out the other. The real magic of fiber is what concoction of “special” ingredients they lace into the core. Heading away from the glass there are a slew of different jackets, coatings, tubes and armor options available to help protect the glass for whatever application it’s needed for. Five sentences later, you’ve just completed Fiber 101.
Onto our old friend: OM1. Generally speaking, we’re talking about legacy 62.5 multimode fiber found in aging backbones, short distance telecom room links and rack interconnects. It’s the meat and potatoes type of fiber, always around and usually tolerable. I realize the above statement is a large, vague generalization. The keyword here is aging. It’s been around for years, gets the job done in short distances and looks cooler than copper links. Unfortunately our trusted pal is being phased out by its bigger brothers OM2 and OM3. But don’t gut it out yet! You might be surprised what you can actually push over a strand of 62.5…
OM2 and OM3 fiber have a different size core, 50 microns vs 62.5 microns. The smaller core ultimately yields a higher throughput that spans greater distances when compared to OM1. OM3 steps it up a notch with the fact it’s laser optimized, or as I like to think of it, it’s the turbo version of 50 micron fiber. Its core harnesses the latest technology found in the transmitters/receivers actually producing and interpreting the light pushed over the fiber. It only took us four sentences to get through Fiber 201.
I came across a recent client that had a plethora of OM1 fiber throughout their campus. It spanned between buildings and most of their telecommunication rooms. They were preparing to upgrade parts of their network to support 10 Gig applications. They knew they had to upgrade their core switching equipment to make it happen and were under the impression that new fiber was necessary as well. With a limited budget, the light at the end of the tunnel (no pun intended) was rather dim.
In addition to different types of fiber that are available, there are also a slew of transmission standards, or protocols, that equipment communicates with. Examples of 10 Gig standards include 10GBASE-SR, 10GBASE-LR, 10GBASE-ER, 10GBASE-LX4, etc. Each standard differentiates itself with what type of fiber is required coupled with their respective length limitations. Equipment modules may or may not have to be purchased depending on what standard one plans to use. OM1 and 10 Gig is possible, but the length limitations are quite severe. It’s definitely not OM1’s best application, yet it can be done under certain circumstances.
It was a long shot, but I suggested that we test their existing OM1 plant to the 10GBASE-LX4 standard. At just under 1000’ between buildings, it was the only 10 Gig standard that even had a chance of testing out. Fortunately, the 10GBASE-LX4 pulled through and was able to test out perfectly (-2db of headroom too). Once we had determined the OM1 could handle the 10 Gig, they were off to shop for equipment.
Instead of paying to have their OM1 gutted and new fiber pulled in, they were simply able to order their new switches with the appropriate modules to handle the 10GBASE-LX4 standard. When their budget can support a new fiber plant, they’ll only have to order different modules to accommodate the new fiber. The bottom line: they were able to stretch a few extra years out of their original OM1 fiber plant investment, purchase new equipment to support 10 Gig, and prepare for a seamless migration to new fiber down the road.
