Dense WDM alleviates Net congestion
By James M. True, Vice President of Marketing, Osicom Technologies Inc., Santa Monica, Calif.
Horror stories of millions of frustrated Internet users-and staggering statistics about the bandwidth squeeze-are all too familiar. The Internet alone is growing at an astounding rate: 200 million users will be logging on by 1999, according to a United Nations report. Futurist George Gilder points out that Internet traffic has grown a hundredfold in the last 80 days.
Consider this: The Internet is only one form of communication contributing to the bandwidth squeeze. Add in the heavy flow from telephones, faxes, pagers, PCS and LANs and you begin to see the problem. The true promise of the information age-movies on demand, continent-to-continent medical imaging, global collaborative engineering, ubiquitous videoconferencing-still seem to be a distant pipe dream. The problem is the pipes carrying this unprecedented level of information are choking.
Just a few years ago, long-distance carriers and private operators dug up the whole country, congested metropolitan areas and countryside alike, to string 25 million miles of optical fiber to meet the demand for bandwidth long into the future. Quite surprisingly, these "future-proof" fiber-optic networks are already becoming exhausted.
Today, the fiber-based infrastructure already carries enormous amounts of traffic, and the advent of the Internet has added to this critically taxed system. Breakthroughs in photonics technology, specifically in dense wavelength division multiplexing (DWDM), can now relieve the bandwidth squeeze by exponentially increasing fiber capacity without the installation of additional fiber. Why photons over electrons?
One industry observer explained the subtle difference between photons and electrons this way: "If your knowledge of physics is inadequate or out of date, consider this analogy: the old-fashioned hand semaphore. This was a handy means of sending vital information over distances where human voice could not carry. Light reflected off the semaphore on one ship traveled to the other ship in the blink of an eye. But the velocity of light doesn't tell you anything about how much information the semaphore could convey in a second. The data-moving speed was a function, rather, of how quickly the semaphore operator could move his arms. Well, photons can wave their hands more rapidly than electrons."
The theoretical capacity of optical fiber is almost limitless. Practically, the speed of fiber to date has been limited by the switching speed of transistors-or electrons-which begins to top out at 2.5 Gbits/second. Optical multiplexing technology called wavelength division multiplexing (WDM) doubles the capacity by making possible the simultaneous transmission of two optical signals on discrete wavelengths over a single fiber. Dense wavelength division multiplexing (DWDM) adds a new dimension to this process, and recent advances in narrow-line-width technology allow for multiple discrete wavelengths to coexist within a single fiber, resulting in several optical signals' filling a common fiber conduit with "virtual" fibers.
As a result, DWDM systems currently on the market can transform existing fiber from a dedicated single-application medium into a versatile conduit capable of simultaneously transporting several independent applications and increasing its total bandwidth from 2.5 Gbits/s to 40 Gbits/s.
Long-distance providers were the first to invest in DWDM equipment to maximize their existing fiber networks' capacity while keeping their infrastructure costs low in their competitive market. Although many of the big DWDM providers, such as Lucent and Ciena, are catering to the long-distance market, the metropolitan market is quickly emerging with a different set of needs.
That market is intensely competitive and includes Local Exchange Carriers (LECs), Competitive LECs (CLECs) and Competitive Access Providers (CAPs). These metro service providers must not only increase bandwidth of their existing fiber, they must also provide a broad mix of services, network configuration flexibility and network reliability that guarantees restoration without a huge investment.
These providers are forced to work with the existing fiber because the cost of laying new fiber in metropolitan areas is prohibitively high. In addition to cost, adding new fiber also encounters lengthy litigation and regulatory delays. Many metro/local carriers do not have the capital available to physically add fiber in the network. With such obstacles, these organizations are searching for a solution tailored to their needs.
Since competition is centered on the services provided, those carriers are dealing with a wider variety of customers and must support data traveling at different speeds and in varied formats. Competition is intense and success depends on handling a broad mix of applications-any type of data, voice or video-on short notice and at a competitive price. Data transparency is critical.
As metro/local carriers build out their network to end users, bidirectional functionality over a single fiber becomes increasingly important to help control costs.
"Cost is one of the most important factors holding off many smaller carriers from implementing DWDM in their networks," concluded Frost & Sullivan market research. "Especially in the local exchange carriers' networks, with many short-haul applications, DWDM systems may not be an economically viable option for bandwidth expansion at this time." Even so, DWDM stands out as the preferred solution to maximize the existing fiber investment, thereby increasing bandwidth while offering the flexibility to handle diverse data formats. The challenge now for DWDM providers is to offer solutions that are affordable for metro/local carriers.
DWDM providers are answering the call with recent product introductions specifically for metro/local carriers-Osicom Technologies' GigaMux is a good example. DWDM provides transport for alternative access and switching schemes such as Sonet, ATM, ISDN or xDSL. As these various technologies battle for market share in the coming years, DWDM can grow along with any of them because of its format transparency. This puts metro/local carriers in a position to grow as the market needs change since DWDM systems don't care what type of signals are being transmitted.
Integrated systems management schemes, billing and pricing of services are also important issues for metro/local carriers.
In the future, competitive metro service providers may either purchase or lease these wavelengths and, in turn, offer digital services to end users, resellers or private network operators. This will result in numerous players' offering a variety of new services to both business and residential customers over common infrastructures. Since metro/local carriers are dealing with more than fixed transmission formats, special management and billing tools are needed to competitively expand and offer a variety of services.
With so many changes ahead, metro/local carriers are facing the tough challenge of how to increase bandwidth while remaining competitive. As DWDM providers scramble to meet the needs, one thing is sure-there is no stopping our hunger for bandwidth.
PS> It is good that FIBR understands the problem. |
