DSL: Still Waiting

Digital subscriber line technology will speed network access-if you can get it

By Kelly Jackson Higgins

o pain, no gain. That's been the way of life for remote users who have endured the painfully slow dial-up drill or battled quirky ISDN lines for access to the Internet or their corporate network. But an answer to their bandwidth problems may be in sight, with services based on digital subscriber line technology set to arrive in metropolitan areas starting this summer and fall.

Digital subscriber line (DSL) technology pumps up existing local copper telephone lines to between 10 and 100 times the speed of traditional dial-up modems-typically at a lower cost than dedicated high-speed (1.544-Mbps) T1 lines and, say early users, without the headaches of ISDN. Participants in DSL trial s say these full-time dedicated links to the Internet or intranets are so fast they feel like LAN connections. Another plus: Some DSL services support both data and voice, so users can consolidate their data and voice lines.

Some users have already found the raw bandwidth and economics compelling. "We were looking to open up our pipe," says Doug Herrick, manager of computer services for litigation support and business consulting firm Charles River Associates in Boston. Herrick's company uses a type of DSL service called single-line DSL (SDSL), from Cambridge, Mass., service provider HarvardNet, for Internet access. Charles River thinks it got a good deal: It replaced a $400-a-month, 56-Kbps dedicated line with Harvard- Net's $800-a-month, 768-Kbps SDSL line-getting nearly 14 times the bandwidth for twice the price.

Ready to try DSL too? Not so fast. You can't buy a DSL modem at your local chain store yet, nor can you order DSL service from your local telco. So far, only a handful of service provider s-mostly regional providers or independent carriers such as HarvardNet, InterAccess, IoNet, and UUNet Technologies- sell DSL services. Larger companies such as Bell Atlantic, GTE, MCI, Pacific Bell, SBC Communications, and US West Interprise are running DSL service trials, but most don't plan to formally launch their services until late this year or early next year. Still, analysts expect DSL will catch on quickly: TeleChoice Inc., a consulting firm in Verona, N.J., expects about 750,000 DSL lines will be deployed this year and 1.2 million in 1998.

Several Flavors
DSL comes in several different flavors designed for different applications. Most vendors plan to offer Asymmetric DSL (ADSL), so called because it shoots data to a user's PC at 1.5 Mbps or faster but lets users send data only at much slower speeds-16 Kbps to 640 Kbps. For that reason, it's aimed mainly at users that need Web access to the Internet and intranets. ADSL services typically include access to the Internet or a corporate in tranet and a DSL modem. Like other DSL services, they provide a dedicated connection at a flat monthly rate.

Some service providers, such as MCI and US West Interprise, plan to roll out high-data-rate DSL (HDSL) services that run at 1.5 Mbps to 2 Mbps in both directions-so they're suitable for a broader range of applications. HDSL is considered an alternative to a dedicated T1 line. UUNet already offers another variant: ISDN DSL (IDSL), which delivers 128 Kbps in each direction using existing ISDN modems.

Possibilities Open Up
A fatter pipe to the home or small office opens up some interesting possibilities. David Kirby, director of TeleHealth at Duke University's Medical Center in Durham, N.C., uses an ADSL link for videoconferencing from home, something he wouldn't have considered with his old dial-up link.

Kirby says the technology lets doctors access MRIs and other images from desk top machines. Because each user gets a dedicated ADSL link, it can feel faster than a shared 10-Mbps LAN, Kirby adds.

ADSL also could displace some frame relay networks. James Karney, adult services manager for the Irving Public Library in Texas, says the library is considering using ADSL to link branches to its catalog database. Today, they are connected by frame relay, but the growing number of CD-ROM-based resources in the database has strained the network's limits. "It's possible to access full-text articles of the Dallas Morning News over frame relay today, but if you have 150 users on the system they tie up too much bandwidth," says Karney.

But before DSL can replace frame relay or other links, service providers must be able to deliver it-and that's taking a long time. Long-distance providers say that's the fault of local carriers, while some local carriers blame the condition of the local lines.

To provide DSL service, service providers must install DSL equipment at local carriers' switc hing facilities, known as copper plants. But Shawn O'Donnell, MCI's director of transmission engineering, says the company has hit snags, such as space being unavailable for MCI's DSL equipment. "The [regional Bells] are dragging their feet," he says. Critics of the Bells say the companies are stalling while they get their own DSL services out and figure out how to extend the life of their ISDN services.

The Bells, of course, paint a different picture: They say they're still testing local lines to see how well DSL service stands up to interference. But Kieran Taylor, TeleChoice's broadband consultant, says his firm estimates that about 80% of local copper loops are DSL-ready today.

Ralph Montfort, manager of network products for UUNet, in Fairfax, Va., says it's not that the Bell companies don't want to open up their loops; they just haven't established a uniform procedure for provisioning DSL lines.

Pricing is another big factor in the speed of DSL deployment-and DSL equipment prices have alrea dy fallen substantially. A year ago, a DSL modem cost about $3,000. Today, it's around $250 to $300. ADSL services are expected to cost $60 to $175 a month, including a DSL modem. That's still more than what dial-up users pay today. But it's more attractive if users can consolidate voice and data lines: Compare ADSL prices with $20 per month for a voice line, $20 per month for a second line for a slow dial-up, and $20 per month for Internet access.

There are a few trade-offs with DSL technology. Like any copper-based wiring, DSL services are susceptible to electrical interference. A T1 in the same bundle could cause blips on the DSL line-a problem that occurred at Microsoft, which plans to expand its 160-person ADSL trial with GTE to 1,000 employees by October. "Apparently the line we picked was in a bundle with lots of security equipment and T1s," says James Webb, program manager for Microsoft's ADSL trial. "The interference from these caused the DSL line not to work very well. Once we switched bundles, it was fine."

Larry Buckmaster, chairman of ConsulTech, a Chicago consortium of computer consultants, says interference had an even worse effect on his ADSL line from provider InterAccess Co., in Chicago. The line simply died, he says: "Nothing was coming through."

Some service providers warn of other potential problems. They've based their investment on the expectation that most users won't exploit the full bandwidth of their DSL service. But if that expectation is wrong, they say, performance will suffer and they'll have to raise prices. "ADSL is a replacement for a modem service," says Leonard Conn, CEO of regional ADSL provider IoNet in Oklahoma City. "We can't have users abusing the service with servers running off it and eating up the bandwidth. There would be no way for us to keep pricing intact."

Standards Lacking
One indication of DSL's youth is a lack of standards: For now, you need equipment from a single vendor from the user's PC to the central office network. That's o ne reason most service providers include a modem with their DSL offerings.

Despite the newness of the technology, users say setting up a DSL link is fairly painless. Typically, service providers visit the customer's facility to install the only equipment the user needs-a PC Card modem from 3Com, Westell, or another manufacturer.

DSL services initially will attract businesses, says TeleChoice's Taylor, though residential use will account for about 60% of the market by 2000, when 6.4 million DSL lines will be installed.

If DSL services become widely available, and the price is right, DSL just might put ISDN out to pasture, experts say. Already, ADSL in many cases is cheaper and faster than ISDN: ISDN services in Oklahoma typically cost about $92 per month, says IoNet's Conn; users must also pay about $300 for an ISDN adapter. By comparison, IoNet charges $95 per month for ADSL-based Net access.

DSL has another big advantage over ISDN. With ISDN, users must still dial up each time they want to access the network, and they're charged for the length of the call. DSL has neither of those drawbacks. "There's no modem negotiation with DSL," says ConsulTech's Buckmaster, who's switched from ISDN to ADSL. "When I call for a file on the Web, it's almost there as soon as I press the button."

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