i know this is a slightly dated article, but would you comment on the photonic switching and its implications for cien?
SEEING THE LIGHT
Photonic switching may be a long way off or just around the corner--but it's important, and it's coming.
By Luc Hatlestad
Paradigm shift. Philosopher Thomas Kuhn's coinage has become the most overused, banal phrase in the high-tech industry--and very nearly meaningless. Yet it persists, largely through the favor of public relations professionals, who promise in barrages of press releases that this new widget is the one that will change the face of technology forever. But sometimes paradigms do shift, and on rare occasions it really is a single product or technology that brings about the fundamental change. Technologists and engineers devote their lives to creating these insanely great things. This quest is the high-tech industry's lifeblood. And it's this quest that helped create photonic switching, which really may be a paradigm shift.
The need for speed
It must be noted here that several other paradigm shifts will likely occur before photonic switching, sometimes known as optical switching, has its day in the sun. For the moment there simply are too many questions about its price and performance, and the networking industry's mainstream researchers are still tied up with Asynchronous Transfer Mode and Gigabit Ethernet. But earlier this year, when we asked a group of executives from small and midsize networking companies what they most feared (see "Switching to IP"), they told us that, like everyone else in this business, they feared a revolutionary technology--a paradigm shift--that might put them out of business. For the networking industry, photonic switching could create this sort of upheaval.
It will be at least six months, and perhaps even a few years, before the first commercial applications of photonic switching are available. The technology has yet to come up on the radar of most industry switching analysts. Although large companies like International Business Machines and Texas Instruments are committed to developing their own variations of photonic switching, The Red Herring discovered that the university research lab still is the best place to look for the technology.
Photonic switching involves storing data on photons--packets of light--and using the photons to transmit, store, and manipulate information. In its ideal form, photonic switching will greatly outperform the current electrical methods. "To this point, switching has been deployed through purely mechanical motion, but the disadvantages of this method are its comparative slowness and the unreliability of its moving parts," says Joseph Goodman, a professor at Stanford University and a cofounder of the photonic switching company Optivision (www.optivision.com).
The idea that there's a speed problem in switching might be news to those developing ATM and Gigabit Ethernet. These technologies have only recently been deployed on network backbones, reaching unheard-of speeds, and since most corporate desktop users are content with a T1 line, why the rush to light speed?
The pat answer is the Internet bandwidth bottleneck. As more people discover the Web and begin using it for games, videoconferencing, and other bandwidth-hungry applications, service providers are finding it more difficult to alleviate traffic problems and keep customers happy. Simon Fok is CEO of GigaLabs, a switching company that recently announced a Gigabit Ethernet switch with a 16-Gbps backplane. With speeds like this in an affordable switch, it's hard to see how the industry could so desperately need more, but even Mr. Fok is aware that it does. "Photonics initially has been a niche product, but we're getting to a point where it's probably the only way to get the speed you need," he says. "The applications for it are few, but they're important."
Darkness before the dawn
What's currently keeping photonic switching from escaping its niche are issues surrounding price and performance. Although the technology can produce spectacular results in a vacuum, in the real world it's still contending with the problem of data loss. "Loss is always a very critical parameter in switching," Mr. Goodman says. "Early switching technology had very high losses, and its applications were limited to transmission over very short distances."
There are myriad ways to pursue optical switching with acceptable loss. One method involves pumping lasers through a tunnel, with the light forcing open a shutter at the other end. And a pet project of IBM's called wave division multiplexing (WDM) takes data from several sources and switches it arbitrarily to various destinations. Its secret is that each source has a laser with a slightly different frequency, and each receiver at the other end is tunable to that frequency.
The drawback of these approaches, and all others within photonic switching's realm, is cost. "These switches can cost several thousand dollars apiece, so only the U.S. government can afford them," Mr. Goodman says. "The problem is, the cost won't drop until the market demand increases, and the market demand won't increase until the cost drops."
This is the catch-22 that will snag photonic switching for the foreseeable future. "There's a big difference between what is possible and what is sellable," says Tom Nolle, president of CIMI, an industry consultancy. "Even if a technology is useful, it may not be economically feasible. The problem with terabit trunks, for example, is that they need terabit switches, and we're a long way from being able to pay for that."
Even evangelists like Mr. Goodman agree that the price of photonic switching will remain its biggest question mark for some time. "Although increasing the usable bandwidth of optical fiber will bring down overall costs with time, the arrival of optical switching won't be as early as has been predicted because the cost of electronic switching is also dropping," he says.
Calling on the telcos
Given that massively monied organizations like the U.S. government are a limited market, Optivision has turned its attention to the next-most-logical consumers: the telcos. Although the company's government contracts require that its officials zealously guard information about ongoing research endeavors, Mr. Goodman did say that Optivision's expansion toward the consumer arena would begin with a partnership with "a major telco." (He refused to identify the telco in question, but Optivision observers say the company has a close working relationship with American Telephone & Telegraph.)
Although cryptic in his description, Mr. Goodman says the target application for the project will enable the telco to switch all the channels in one fiber to all the channels in another fiber, a process known as multiplexing. "We think this is where the first commercial application will occur," Mr. Goodman says. "It's probably needed right now, but it won't be deployed for a year or two because development is ongoing."
He says it will be midyear or possibly 1998 before privately owned Optivision makes public its photonic development plans. "We've found a role that not everyone is aware of yet," Mr. Goodman says. "We've kept quiet because we worry about the ability of a small company to compete with a Lucent if the word gets out. But on the other hand, a good market to us may not be a good market to them."
Although details remain sketchy, observers say the telcos may be just the right target. They add that it's incumbent upon the telcos to take advantage of the technology before ISPs or some other industry does. "The technology is tied far more closely to the telcos and the cable companies than to the electronic switching vendors," says Jayshree Ullal, a vice president of the workgroup business unit at Cisco Systems. "But if telcos don't jump on optical switching as a service and it takes off, it then becomes a way for corporations not to rely on leased-line providers for their connections."
Patience, patience
But given the relative infancy of ATM and Gigabit Ethernet and the lack of urgency felt by average corporate users to upgrade their network connections, Ms. Ullal still thinks photonic switching's day is a ways off. "Every year recently has been heralded as the year of optical fiber, so this year is no different," she says. "But switching beyond gigabit speeds is still undefined. Most desktops are still at 10-Mbps speeds, and it probably will be five years before we see massive amounts of gigabit switching out to the desktop, so ideas of photonic switching are still chiefly ideas at this point."
Photonic switching may be appropriate for more than linking up the Internet. Ms. Ullal says businesses like banks could use fiber to link up their branches, or the wires could be used as a high-speed (and, no doubt, high-premium) connection between banks and telcos or ISPs. Mr. Nolle sees a possibility of embedding photonic functionality into silicon to alleviate the heat-emission problems currently faced by silicon-chip makers that are migrating to smaller manufacturing processes. If chips can be developed to send light signals instead of electronic impulses, the need for transistors, and thus the heat problems, will be eliminated.
Mr. Goodman and his cohorts don't deny the potential of photonics in these areas. In fact, Optivision does research in at least four variations of the technology. But for photonics' big splash, the company is still betting on the WAN switching arena. The advantages are photonics' speed, its potential accuracy, and the fact that because it switches light particles, it works with any pre‰xisting technology. "It's best applied over long-distance transmission networks, or on networks with a large aggregation of data, or in local networks that connect very high-performance computers," Mr. Goodman says. "It's primarily focused on gigabit speeds and beyond, but at least in the case of WDM, its time is not some undetermined point in the future. It's being deployed now."
With ATM and Gigabit Ethernet still finding (or escaping from) their niches, there may be a paradigm shift or two in the networking arena itself before photonic switching becomes widely deployed. But by now the momentum of the industry as a whole and of the Internet in particular is undeniable. More people than ever are hooking up and dialing in with increasingly powerful computers and running applications that demand more bandwidth than ever. Many solutions are out there for alleviating what is sure to become a monumental need for bandwidth, but it's going to be tough to top the speed of light.
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