Advanced Networking: Fueling Fiber in the Enterprise

Today’s enterprise network infrastructure must accommodate not only broadly distributed virtual and cloud architectures, but also maintain near-perfect availability for a generation of data users who simply will not tolerate loss of service, and a business model that can’t, either.

To that end, organizations have rolled out a steady stream of advanced network architectures designed to fulfill modern requirements without the time and expense of major forklift upgrades. At some point, however, legacy infrastructure – that is, the very wires that carry digital information – can no longer keep up. When that happens, new plant must be provisioned.

Taking another look at fiber

In these days of software-defined turmoil, enterprises of all sizes are turning to the most flexible and far-reaching cabling solutions they can find. That invariably leads to fiber. In previous generations, fiber’s perceived value derived primarily from its small form factor and long-distance capabilities, not necessarily its bandwidth advantages. As new solutions hit the channel, however, fiber is emerging as the go-to technology for the new millennium.

“New architectures, such as top-of-rack solutions, push fiber to the data center cabinet, which drives fiber deeper into the data center infrastructure,” said David Kozischek, enterprise market manager for Corning Cable Systems. “Where fiber traditionally ended at the row, it is now driven to the electronics cabinet.”

And the push for rack- and board-level fiber is just getting started. The interconnect in particular looks ripe for an optical take-over, according to Research and Markets, which predicts the market will double between now and 2018, to about $2.2 billion. As organizations struggle to keep pace with the massive parallel workloads of Big Data and scale-out collaborative environments, legacy copper plants will fall prey to increasing numbers of bottlenecks. On top of that, they’ll become too expensive to provision and manage.

Beyond the rack, enterprises are also struggling with the fact that speeds at the switch and in storage have risen dramatically in the past few years and will soon hit new orders of magnitude. With Ethernet migrating from 1 GbE to 10 to 40 to 400 and storage already pushing past 16 Gbps to 32 and even 64, traditional copper cabling just won’t cut it for much longer.

Single-mode fiber for the data center

All fiber is not the same, however. And enterprise managers wringing their hands over the prospect of tearing out their recently installed OM3 networks in favor of the even more expensive OM4 standard can take heart: a number of recent developments make it possible to build advanced network architectures around single-mode fiber, the same low-cost glass that telecommunications companies use for the really long haul.

Chief among those developments is silicon photonics (SP). Long a fixture at Infiniband-based high-performance computing (HPC) centers, SP is only just now making the jump to Ethernet, where it provides a ready means to deploy single-mode fiber at medium distances, around 100 to 150 meters. This makes it an ideal data center solution because it costs little to deploy, requires fewer board-level components, and provides a high degree of signal integrity with low power consumption.

“In today’s data center mode, everyone is looking at the five-year plan,” said Brent Hatfield, product manager of active optics at Molex. “Single-mode fiber is the least expensive solution by far, and its bandwidth is pretty close to unlimited. With silicon photonics, you gain the distance you need in the data center, without the power or cost penalties of other active cable solutions.”

Depending on the configuration, SP-based single-mode solution deployments can require a lower capital outlay than OM4 and will likely become even more cost-effective as new generations of the technology emerge. Next month, Intel plans to unveil a new SP-based interconnect, MXC, with the potential to drive up to 1.6 Tbps per lane using a smaller form factor than current connectors. The technology is on the docket for the Intel Developer Forum in San Francisco from September 10-12, where Intel will demonstrate it using Corning’s ClearCurve platform.

At the moment, however, most see silicon photonics strictly as a data center solution: capable of connecting servers, near-line storage, and rack units, but not client devices in the wider enterprise. Out on the LAN, distances are a bit longer, and active optical fiber solutions like SP and the various OM versions remain prohibitively expensive. But you can get away with low-cost single-mode fiber using new generations of passive optical technology.

Benefits of passive optical LAN

Again, taking a cue from the telecommunications industry, passive optical is usually associated with fiber-to-the-home architectures, because it can be implemented at low cost and without the complex repeater and amplification technologies that characterize active plants. This makes it an obvious choice for the enterprise LAN as organizations look to convert data networks into flat, fabric-based infrastructure.

Recently, a number of leading firms like Corning, 3M, and IBM launched the Association for Passive Optical LAN (APOLAN) with plans to educate the enterprise on the benefits of the technology. According to David Cunningham, chairman of the association and manager of passive optical LAN marketing at Corning, passive optical’s appeal lies in its ability to push switches and other components to the end points of the network, providing for a more streamlined and scalable infrastructure.

“When you take the electronics out of the middle, you remove the complexity of telecom closets, power and cooling, switching and all the rest,” he said. “The only space you need is for the network itself, and the footprint can shrink down to the point that you can eliminate the closets on each floor.”

For the moment, at least, most enterprises get by with current LAN technology. But as data architectures become more distributed and new generations of users embrace two-way video, social media, and other bandwidth-heavy applications, pressure on the LAN will increase. Enterprises should act now to ensure the ability to handle data loads as they ramp up.

“Think of it as a major city with no interstates,” Cunningham said. “Without the ability to accommodate traffic, growth is inhibited. With the interstate in place, traffic flow increases, and so does commerce.”

The cost of implementing single-mode fiber has become very competitive with traditional copper infrastructure, to the point that some large organizations may be able to deploy passive optical solutions for less than half the initial budget. And new generations of fiber are proving much more flexible than earlier designs, with bend radii now approaching 5 mm before signal strength is affected.

Media converters to bridge the copper/fiber divide

Despite these benefits, however, rip-and-replace isn’t a viable option for many organizations. Perhaps someday the all-fiber data center will be commonplace, but in most cases a vibrant mix of copper and glass will run through enterprise walls and cabinets for some time.

It’s important, then, for network managers to familiarize themselves with current media conversion technology: devices that allow digital information to make a seamless transition between the two formats.

According to Al Davies, director of product management at Perle Systems, media converters are the best way to ensure legacy copper plant can take part in the high-speed networking architectures currently under development. As switch technology evolves to 10 GbE and beyond, a top-of-rack converter allows legacy servers to communicate with aggregation switches further downstream, where fiber is most likely to be deployed. That allows enterprises to pursue a gradual fiber conversion plan when the time comes, rather than face the daunting prospect of a facility-wide forklift upgrade.

“Media converters allow you to mix and match different types of switches,” Davies said. “It’s a way to protect your investment as new technologies, most likely fiber-based, evolve.”

Most media converters accommodate single and multimode fiber, as well as 10/100/1000GbaseT, Fast Ethernet and 10G to fiber formats. It also helps if they provide secure remote management capabilities and advanced features like link pass-through and fiber fault alert.

“Copper has a limit of about 100 meters, which isn’t that far,” Davies said. “By converting signals to fiber, you now have the ability to reach that new office or the remote part of the warehouse.”

With both economics and longevity in fiber’s favor, it’s hard to envision the enterprise of even the near future without a substantial fiber infrastructure. When it comes to future-proofing today’s data center, the most fundamental step is to ensure that next-generation virtual and software-defined environments have enough bandwidth to meet tomorrow’s user demands.

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