Although some observers have questioned the long-term health of DSL, a new variant of the core technology, SHDSL (Symmetric High-bit rate DSL), could revive interest in the high-bandwidth, copper-based service, especially for businesses.
SHDSL promises data rates of 2.3Mbps over a single copper pair, as opposed to the 1.5Mbps speeds of conventional DSL lines. Moreover, the new standard can allegedly reach distances 30 percent further than regular DSL, and because it supports repeaters, latency for high-bandwidth applications (such as voice and streaming media technologies) is expected to be very low. The SHDSL standard was approved by the ITU (International Telecommunication Union) in early February.
Although SHDSL is not expected to be rolled out in the United States until later this year or next year, vendors are already gathering around the standard. At the recent DSLCon trade show in Denver earlier this month, Lucent Technologies Inc. announced SHDSL enhancements to its Stinger line of DSL concentrators. Lucent spokesmen and spokeswomen said the upgrades will provide higher performance, better power consumption, and improved spectral compatibility over existing symmetric DSL technologies.
Lucent's SHDSL play will be aimed primarily at enterprises that want to extend broadband to telecommuters and deploy VODSL (Voice Over DSL) technologies. The upgrade is expected to cost less than US$250 per port.
Smaller companies are getting in on the action, too. In June, Efficient Networks Inc., a Dallas-based equipment manufacturer, will roll out its 5950 SHDSL Business Gateway, a customer-premises device aimed at small to midsize businesses and branch offices.
In addition to supporting the SHDSL standard (with a maximum distance of 20,000 feet), the 5950 product will come with an auto-sensing 8-port 10/100 Ethernet interface, a user-friendly GUI, and a built-in firewall. The $599 device will support TCP/IP and static routing, and a wire-speed VPN will be optional.
Many analysts are predicting that SHDSL will let ISPs deliver more stringent SLAs (service-level agreements) to subscribers, which could be especially attractive to businesses. Another key to enterprise adoption could be SHDSL's low implementation costs: Like standard DSL, SHDSL can be delivered over an existing copper-wire infrastructure.
"[SHDSL] will become the dominant choice for DSL in businesses," predicted Jon Cordova, an analyst at San Jose, Calif.-based Infonetics Research. "The providers are looking for different ways of making money in the DSL space, besides just providing connectivity."
Cordova cited the greater throughput, longer distance ranges, and support for services like VODSL and particularly VPNs as drivers for the new standard.
"The killer app for broadband connectivity is VPNs," Cordova said. "That market is becoming very real. Businesses are looking for ways to save money, and VPNs are a natural choice for that."
Accordingly, Efficient Networks' move into the SHDSL space is all about the enterprise market.
"When we look at the needs of the business user, we see needs not just for high-speed access, but also for high availability," explained Dano Ybarra, Efficient's vice president of business management. "They need a reliable, robust, scalable platform to meet their needs -- from simply sharing an Internet connection to the needs of tomorrow, including security, high availability, VPNs, manageability, and extensions into the space of voice and video."
"Efficient has a strong play," Cordova said. Cisco Systems Inc. and Alcatel SA, with strong presence in the xDSL market, are also expected to be significant forces in the nascent SHDSL space.
But SHDSL is not likely to crack the large enterprise market. "There's other types of connectivity in the enterprise, where DSL is not the primary WAN technology, like ATM, Ethernet, and frame relay," Cordova said.