Access networks are the next battlefield

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The fiber-optics marketplace has witnessed several good street fights over the last couple of years. First came the channel-count competition waged by dense wavelength-division multiplexing (DWDM) companies, each of which took turns claiming that its systems provided the highest number of channels per fiber. This lasted until the counts extended well beyond the amount any carrier expected to use in the foreseeable future. Thus, with the exception of the occasional flare-up in pursuit of the new long-haul trump card--the number of terabits can you transmit--this battle has abated. Fortunately for fight fans, the small-form-factor connector wars erupted within the TIA-568B standards process. While the haze of battle shows signs of clearing, it appears that this skirmish will continue for another year or two.

But those of you looking for new forms of competitive entertainment will be pleased to hear that another market segment shows signs of heating up. Judging by a recent avalanche of new companies and new ideas, the access network space looks to be the site of the next big shootout.

Ladies and gentlemen, may I direct your attention to the suddenly teeming world of passive optical networks (PONs). As readers of last month's issue already know, PONs have three basic building blocks: a transmitter, passive splitter, and receiver. Depending upon how close to the end user the receiver is installed, PONs can support a wide variety of architectures, from the relatively timid fiber-to-the-local-exchange network all the way to fiber-to-the-home.

The Full Service Access Network (FSAN) initiative represents the most well known of the PON approaches by far. The four-year-old effort currently has the backing of 20 carriers from around the world, including several of the regional Bell operating companies (RBOCs), as well a host of manufacturers who have served the carriers in an advisory capacity. The consortium has developed a set of technical specifications and requirements for a PON based on Asynchronous Transfer Mode (ATM) that have been codified and accepted by the International Telecommunications Union (as ITU-T G.983.1), the ATM Forum, and the European Telecommunication Standards Institute. The aim is to create a common, open set of specifications that will enable them to choose among multiple vendors for optical-access network equipment.

The specifications do not cover the end-to-end workings of a full access network, however. To launch field trials of FSAN-compliant ATM PONs, four carriers have had to promulgate an additional set of specifications, which they call the Common Technical Specifications. The fact that the consortium comprises some of the leading national carriers from around the world that have the ear of the major standards bodies implies that FSAN-based ATM PONs will likely be the first option for some of the RBOCs and incumbent national carriers in Europe and Asia.

Competitive local-exchange carriers in the United States and their brethren overseas hope to make a living being more nimble than the Baby Bells and national incumbents. Several new startups serve this market with alternatives to the FSAN brand of PON. Two of these companies introduced themselves to Lightwave's readers last month. Optical Solutions says FSAN architectures address only part of the access whole and that its FiberPath system can provide broadband services. AllOptic Inc. has introduced equipment that can create tree, ring, and bus networks. These companies have now been joined by Quantum Bridge Communications, which says its new equipment will provide more-economical PONs with a wider variety of interfaces and line speeds.

Of course, PONs aren't the only option for fiber in the local loop. This makes for a lively debate among vendors and carriers-and promises plenty of entertainment for those awaiting a rematch between Lennox Lewis and Evander Holyfield.

Stephen M. Hardy
Editorial Director and Associate Publisher

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