Economics push fiber closer to the home
BY STEPHEN HARDY
By Arielle Emmett
fiber-exchange.com
Meeting the demand for bandwidth in the access market today isn't just a question of deploying digital-subscriber-line (DSL) technology and cable modems. Carriers around the world are now pondering just how deep in the network to drive fiber.
BellSouth, the most aggressive regional Bell operating company (RBOC) on the technology block when it comes to high-bandwidth solutions, is undertaking the nation's largest fiber-to-the-curb (FTTC) deployment to 200,000 homes in Atlanta and Ft. Lauderdale, FL. This is a groundbreaking step, according to Dan Estes, director of BellSouth Consumer Multimedia Services. "Customers are demanding higher-speed bandwidth, and we've started an aggressive technology conversion in the belief that Internet use will increase at an exponential rate," he says.
Interestingly, BellSouth is technology agnostic; it recently announced five new flavors of high-speed DSL in 28 cities—one with 7.1-Mbit/sec downloads—to satisfy Internet and data-hungry users. Yet, the company still believes that "deep fiber" is the longer-term solution and is deploying what it terms "integrated fiber in the loop" (IFITL), actually an FTTC solution using a Marconi Communications DISC*S FiberStar multiservice platform. This deployment brings fiber within 500 ft of the user, providing broadcast video, high-speed Internet data, and the latest voice applications in demographic areas where bandwidth demand is expected to be exceptionally high.
"We're talking as high as 10 Mbits/sec, and potentially 100 Mbits/sec [with fiber] to the home," reports Estes, who notes that the first fiber deployments will match the data rates of comparable BellSouth ADSL (asymmetric DSL) options and tariffs. BellSouth is simultaneously undertaking a technical trial of fiber-to-the-home (FTTH) technology to 400 Atlanta homes using Asynchronous Transfer Mode (ATM) protocols and optical access equipment from Lucent Technologies and Oki Electric Industry Co. Ltd.
"Our objective is that customers would have the same [broadband] experience regardless of technology [either fiber or ADSL]," Estes explains. "There are three economic drivers. We see both [increased] revenue from video and data as well as the expense reduction of the fiber-based network." Given the new economies of volume fiber installation, reduced power utilization, and developments in passive optical components, "fiber-to-the-curb is now cheaper than ADSL plus hybrid fiber coax," Estes claims.
"One factor has been the cost reduction in fiber-optic amplification," he adds. "The enabling technology to allow us to deliver video service is the erbium-doped fiber amplifier. For example, in the integrated fiber-to-the-loop project, Marconi [formerly Reltec Corp.] is providing remote-terminal-mounted fiber-optic amplifiers as well as other components."
BellSouth's drive to put fiber closer to the customer is a matter of technology, timing, and anticipation. "Now is the right time for fiber architectures to take off," says Steve Barreca, president of BCRI Inc. (Birmingham, AL), a research and consulting firm specializing in assessing technological change. "Prior to this time, the technologies weren't developed enough and the market wasn't ready for the capabilities of a full-service, fiber-based network. "
Today, however, the local-exchange carriers (LECs) are being led by deregulation and demand for Internet data and residential video entertainment. "Telcos have to look at either fiber or upgrading twisted-pair copper [to meet bandwidth demand]," affirms Stephen Montgomery, president of ElectroniCast, a San Mateo, CA, consultancy. Although ADSL will be a primary form of access short-term, fiber will drive closer to the curb and home in high-density deployment areas (e.g., condos, apartments, and new housing communities) as well as "old builds" where twisted-pair was deployed before 1975. However, "upgrading twisted-pair by using ADSL is a band-aid," Montgomery contends. "We think the telcos will win out using fiber closest to the home, to the neighborhood or curb, and by using passive optical networks [PONs]." This is a preferable solution to cable modems, he adds.
Less and fewer
In actuality, PON equipment and architecture today is a key part of the new cost-competitive FTTC picture, Barreca affirms. PONs have two inherent advantages: less cost and fewer problems with power and interference. "BellSouth is deploying a new FTTC architecture that's different from what was available a few years ago," Barreca says. "The new architecture uses a hybrid of passive and active devices. You have such active things as wave-division multiplexing and DSL. But you also have a passive optical network in the sense that fibers are fused together and distributed throughout the neighborhood; the optical [erbium-doped] amplifiers don't require that the cables be cut or separated."
In the past, he explains, "[technicians] would have to cut the fiber, plug it into an amplifier, and regenerate the signal and send it down the line. That was probably 10 times as expensive as it is today to use [comparatively simple] erbium-doped amplifiers." He describes such amplifiers as "just a very strong flashlight that shines on the outside of the fiber and excites the photons of the signal. It's very inexpensive."
The standards community is also driving digital services by helping to define the new passive fiber architectures. For example, several U.S., European, and Japanese service providers, including BellSouth, have formed an industry consortium called the Full Service Access Network Initiative under the auspices of the International Telecommunications Union (ITU). While the consortium defines standards for ATM PONs, vendors are beginning to create standards-based, interoperable products enabling transmissions between 155 and 622 Mbits/sec downstream and as much as 155 Mbits/sec on the return.
"I'm betting that 155 megabits or 622 megabits may not be overkill in the future," says Bob Lund, chief technical officer for Optical Solutions (Minneapolis, MN). Optical Solutions has developed a multiservice residential gateway solution for broadband voice, data, and video, now being marketed as a "fiber-near-the-home" product to competitive and incumbent LECs around North America. "What we're deploying today is consistent with ITU standards," he says. "We provide a path for upgrading electronics at the end point to enable [customers] to use fiber-based access architecture far into the future."
Phil Becker, director of product management for passive optical networks at Lucent Technologies, which is offering optical-network termination units for BellSouth's FTTH trial, concurs with the standards view. "The products we're making for BellSouth are not custom," he says. "They can be used by other service providers." Indeed, service providers have already benefited tremendously from setting up global standards for PONs, he claims. For example, ATM PON goes up to 155 Mbits/sec commercially and 622 Mbits/sec experimentally in the lab.
"The various optical components are low cost, and the ATM part is only used to carry information from the central office to the optical-network unit, which is placed on the customer premises," Becker explains. "From the user perspective, they don't know ATM is traveling there." Instead, users get a variety of standard data service options (in the form of PCMCIA cards such as Ethernet cards) and virtually unlimited bandwidth. "ATM is only present for the service provider to deal with quality-of-service issues," he says.
How far is far enough?
RBOCs and competitive LECs are still struggling with how far to drive fiber into their networks. Overall, the verdict is mixed. "If fiber is so economical and works so well, why aren't more RBOCs using it?" asks Mark Cannata, vice president of marketing for Marconi Communications Access Network Systems Group, the company supplying optical systems to the BellSouth FTTC initiative. It also supplies equipment to Sprint LTD, the local access branch of the Sprint long-distance company. "We work with just about every RBOC in the country," he says. "But they were turned off in early days about what it cost to put a fiber-based infrastructure in place, and it's still tough to have a dialog with some of these folks involved in FTTC."
Companies such as GTE, Bell Atlantic, and SBC have been notably cautious about FTTC, bringing fiber to nodes thousands of feet (as much as 12,000 ft) from residential curbs and using standard digital-loop carrier systems based on copper distribution to residential neighborhoods. "Some folks haven't studied [FTTC] much and haven't convinced themselves that they can put in fiber-based infrastructure and pay for it," Cannata says.
In actuality, fiber has been moving closer to the curb all decade. In the early 1990s, Marconi (in its former Reltec incarnation) had collaborated on trial installations of FTTC with US West, which then decided to go with a telephony-over-hybrid-fiber/coax solution in Omaha, NE, where initial field trials took place, according to Cannata.
While other RBOCs hesitated, BellSouth selected Reltec to be an FTTC supplier for field trials throughout 1993-1994. These culminated in full-scale approval for deployments of FTTC throughout the BellSouth nine-state region. "Once they approved the Marconi FTTC system, BellSouth changed the outside plant engineering guidelines [to specify a fiber feeding/distribution system to residences]," Cannata says. "Until the end of 1996, BellSouth did what everyone else did—build digital-loop carrier systems with copper distribution, and that continues to be the way that most companies build out their networks today."
Not everyone is convinced that BellSouth's aggressive FTTC policy is the right one. "Services drive architecture, and if I don't have a revenue driver, why overbuild?" asks John Boe, general manager for network strategies of US West. Like other carriers, US West has been driving fiber deeper into its networks—from 9000 to 12,000 ft from the curb in carrier servicing areas several years ago to 3000 to 4000 ft today using current digital-loop carrier technology. "We call this fiber-to-the-node [FTTN]," Boe says. "Where we're doing fiber-to-the-curb is in selected new land development areas where we expect a high level of data usage and in business parks."
US West is offering full-service options without FTTC. For example, the company's TeleChoice option for customers in Phoenix offers broadcast video and pay-per-view—100 premium channels—utilizing FTTN and very-high-speed DSL (VDSL) technology at the network "demarc" (cross box or feeder distribution point). The VDSL interface creates a broadband residential gateway with three available video channels (which provide a total of 100 channels of content) and one data channel, with data rates up to 20 Mbits/sec to the home.
"The operative word for determining fiber deployment is penetration tables," Boe says. These tables are essentially economic models that determine which geographic areas really need a technology like FTTC to satisfy bandwidth requirements. For example, US West uses FTTC in a new community, DC Ranch (Scottsdale, AZ), that features what Boe calls "upscale homes."
The RBOC will offer up to 52-Mbit capacity to each home. "We'll offer essentially the same services [as TeleChoice], but we expect higher penetration rates," Boe explains. In effect, "we're saying essentially the same thing as BellSouth, that fiber has value," he concludes. "But I'm being more selective where I put it."
The rate of fiber penetration overall remains a matter of speculation. ElectroniCast's Montgomery believes that demand for two-way communications to homes will drive fiber ever deeper toward the curb: "You'll see a trend 10 to 15 to 20 years out. Fiber will get closer to the home...from nodes [feeding] 5000 homes to 2500 homes to 250 homes, and you'll see fiber all the way to the curb." The major roadblock to FTTH, conceived as ultimately a more economical technology given the virtually unlimited bandwidth involved, will be installation. "If homeowners don't want to dig up their lawns, there's no reason to bring fiber to the home," Montgomery says.
Still, many believe that FTTH will be the ultimate direction telcos will take once passive optics prove out at the residential level. "In five years, FTTC will be superceded by passive optical networks and fiber-to-the-home," predicts US West's Boe. "If you can replace the optical network unit at the curb and power it at the home, it will cost less money."
"We think the passive optical network is the right way to go. Copper infrastructure for telephony and high-speed data is already beginning to bump up against practical limits," says Bob Lund of Optical Solutions. The company has already signed commitments to provide over 25,000 units of its FiberPath product to FutureWay Communications, a Canadian service provider in the Toronto area, and to Rye Telephone Co. (Colorado City, CO).
Analyst Barreca also believes FTTH will become a serious future option. "Five years from now, at least 50% of people who access the Internet will be willing to pay a nominal fee to have high-speed access," he says. "It's cheaper to do it over fiber than a copper-based network, and FTTC is the cheapest thing you can do. In the next two years, FTTH will probably become more cost-effective than FTTC; and, in effect, FTTC will evolve into fiber-to-the-home—you're not throwing away your investment."
Companies behind FTTH technologies today will claim a leapfrog strategy, Barreca insists. The point though is that "if you wait three years from now to invest in any deep fiber infrastructure you'll be left high and dry. In Tier II markets, for example, once the penetration rates exceed 15% to 20% for high-speed Internet access, it's far cheaper to replace copper with fiber than continue to add xDSL," he continues. "The LECs who take an aggressive strategy for their markets, getting there first with their full-service network, will be in the driver's seat. Otherwise, a company like AT&T will get there first, and the LECs will be second best."
Arielle Emmett is editorial director of Fiber Exchange's sister publication, Wireless Integration. |
