Big news on the higher-speed Ethernet front. No, not that work has begun on 400 Gigabit Ethernet (GbE), thus setting the bar low, but rather the intention to go for 1.6 Terabit Ethernet (TbE) afterward. Yes, that’s right. After decades of advancing Ethernet in increments of 10, we will now have to settle for a mere quadrupling of speeds each standards cycle. No word on whether the timeline of each cycle will shorten commensurately, though I have my doubts.

So why the sudden change? Surely for such a drastic turnabout to occur there must be an earthshattering reason. Perhaps going for TbE and 10TbE thereafter would rip the very time/space continuum of the universe itself!

It turns out the reason for the biggest shift in the laws of Ethernet since its inception is… wait for it… It is hard. That’s right. The very people who brought you Ethernet, the Internet, and surfing WiFi at Starbucks think TbE might be hard.

I seem to remember no one had a clue how 100GbE might be accomplished when that effort was started. 100G coherent detection is one of, if not the hardest Ethernet technologies ever attempted. 10GBase-T’s computational power would have made a supercomputer blush only a decade ago. And both seem to work just fine, thank you. In fact, if you look at public minutes of all the past higher-speed Ethernet efforts (10GbE, 1GbE, 100M, etc.), the study groups have all had moments of panic and doubt when facing the next big step. All it took to overcome the challenge was the greatest minds in the industry working together as a team toward the betterment of the industry – the very reason standards bodies exist and meet regularly in the first place.

OK, in all fairness, the real reason being given for a shift in strategy is the exploding growth of bandwidth consumption, and the belief that it is better to have a 4X improvement sooner rather than a 10X bump later. An executive of a North American Tier1 service provider recently confided to me, “We gave our OK to 400GbE over 1TbE because we were told we could get it sooner.” Of course, this all depends on the 4X actually arriving sooner, and since 400GbE heavily leverages technology being developed for second-generation 100GbE, this seams a reasonable assumption.

A bigger challenge for 400GbE might be market economics, as it will have to compete with the aforementioned reinvigorated 100GbE. Service providers just got done ripping out all of their regenerators and dispersion compensating fiber (DCF) spools in favor of 100GbE coherent transmission. Now comes word that 16-QAM 400GbE might need the regen’s that were just yanked. A tough sell, to say the least.

Have electrical speeds, bus widths, and laser modulation techniques really run out of steam? Are we doomed to a future of 4X Ethernet increments? Perhaps Fibre Channel had it right all along. Or maybe the ITU has it right with ODUflex. The only thing certain at this point is Ethernet is a-changing. Again, to be fair, the next rate after 400GbE will not be officially decided for years to come. Only time will tell if this was merely a brief detour for Ethernet, or a permanent change in compass heading.

Jim Theodoras is senior director of technical marketing at ADVA Optical Networking.