Voice-over-DSL looks promising, but it has a way to go before it becomes...

...marquee-quality technology

Much like a World Wrestling Federation bout, there's been more talk than action when it comes to voice-over-DSL (VoDSL) deployments. Analysts are hyping its promise, vendors are popping up with prototype devices, and standards groups are hashing out common languages, but so far, the number of deployments has remained infinitesimal, at best. But that situation could indeed change this year, based on the alliances and partnerships that are beginning to form around this technology.

To date, DSL technology has been used almost exclusively to transport data over the Internet at high speeds through existing twisted pair copper links. However, equipment has been introduced in the past couple of years that will broaden DSL's usefulness by allowing the movement of voice and data simultaneously over a single copper link, without architectural changes to existing networks. The payoff: Smaller organizations will soon be able to buy integrated, richly featured voice/data services in a way previously available to only the largest firms. The irony here is that for data-centric competitors, voice service may be the next big thing, providing even greater revenue opportunities in the small and midsize market segment.

How it works

Digital subscriber line is the technology that can add a multimegabit data stream to a regular phone line. With some flavors of DSL, the data channel can be added without disrupting the standard analog voice channel on the line.

But that's not the voice referred to in the term, "voice-over-DSL." VoDSL is more accurately described as voice-over-IP-over-DSL or voice-over-ATM-over-DSL. As such, VoDSL broadband access solutions are generally overlays onto the DSL network, enabling the provisioning of voice services on what started out as a data network.

Today, a VoDSL solution has two basic components: a voice gateway and an integrated access device (IAD). The IAD serves as the interface between the DSL network and the customer's voice and data equipment. Voice and data traffic is converted to IP packets or ATM cells and crosses a DSL link into the carrier's network. The customer premises equipment (CPE) prioritizes the voice packets over data calls to ensure toll-quality voice delivery and then sends the packets over the DSL line.

From a layering approach, VoDSL has several components as well. The physical layer is actually a twisted pair of copper wires. The transport layer can be handled by frame relay, ATM or IP. Another layer is voice coding, followed by the signaling layer and the services layer, which includes such options as dial tone and call waiting.

Helping make voice happen

ishoni’s gateway
 on a chip

VoDSL has been spurred along by equipment manufacturers such as CopperCom, Lucent Technologies, JetStream Communications, TollBridge Technologies and Accelerated Networks.

CopperCom manufactures a solution called LeXSS (Local Exchange Softswitch System) that integrates a broadband access gateway with a softswitch architecture. The softswitch solution is comprised of three pieces: a media gateway, the basic switching fabric; the Copper Controller softswitch that provides the call control; and Copper Commander, the network manager platform. The company also manufactures IADs.

The Santa Clara, Calif.-based company was founded in 1997 and focused on delivering multiple services over broadband. The first products the company produced a couple of years ago were focused on delivering multiple voice lines and high-speed Internet access over a DSL network.

"The crux of the matter is there are tremendous cost savings to be had by delivering multiple services over less infrastructure," says Jennifer Stagnaro, chief marketing officer of CopperCom.

About 50 service providers are using CopperCom's equipment, says Stagnaro. They include Vanion, a Colorado-based CLEC, and N.J.-based KMC Telecom.

As with any new technology struggling to find adoptees, interoperability is a big issue when it comes to VoDSL. While the DSL industry may be mired in standards and the real-world drama of installations and errors, many new efforts to mix voice into access services are under way.

CopperCom's part in this includes a "Many Voices of DSL" partner program. The program's goals include educating vendors on VoDSL technology, promoting interoperable multi-vendor VoDSL solutions for delivering VoDSL, ensuring interoperability with CopperCom products, and support for standards initiatives for delivering voice and data services in the local loop in the ADSL and ATM forums.

CopperCom has taken an early lead by implementing standard management via the ATM Forum's Loop Emulation Service (LES) Embedded Operations Channel (EOC) in its IAD, the CopperCom MXR, as well as the CopperCom Gateway.

"Because of the environment we're operating in, there are so many standards, in particular the environmental standards, that the big RBOCs mandate that we support," says Neil Griffiths, CopperCom's director of product marketing for voice-over-broadband products.

Stagnaro believes that VoDSL service should become more prevalent this year. "If you look at the telecom spending situation in the capital market, the service providers who are going to survive are going to be those that have compelling business models . . .," says Stagnaro. "What is actually driving this sector of the market right now is the opportunity to impact their revenues and bottom line with this technology."

One of the companies CopperCom works with in its partner program is ishoni Networks, a semiconductor company that manufactures a WAN-independent silicon-and-software system that lets OEMs and service providers to more quickly, easily and affordably build IADs and broadband gateway products that offer full voice, data and security services. ishoni also makes sure its chips are tested for interoperability.

ishoni licensed CopperCom's Voice-over-ATM transport specification last year to ensure that ishoni's Gateway-on-a-Chip broadband CPE was interoperable with CopperCom's Gateway. This was part of ishoni's "Total DSL" initiative, which focuses on building strategic relationships with the world's leading broadband equipment and broadband solutions providers, in order to create true "plug-and-play" DSL access for OEMs.


Greg Gum, ishoni's VP of business development, believes one of the reasons VoDSL hasn't taken off yet is because of the current headaches with automated provisioning and billing for DSL services. Yet packetizing voice signals over DSL has the potential to become a "killer application" for DSL, according to analysts from Cahners In-Stat Group. (Cahners In-Stat and CED are both owned by Cahners Business Information.)

"It's going to happen because, in the long run, why have two separate networks to handle data and voice when one network will do fine," says Norm Bogen, director, WAN infrastructure and services for Cahners In-Stat, which recently released an analysis of the VoDSL industry called "Voice Over DSL: A Service Opportunity."

Despite the fact that the nascent market is tiny, at best, some companies are already carving out market leading positions. Infonetics' latest research shows Jetstream owns roughly 34 percent of the worldwide voice-over-broadband gateway market share, based on fourth quarter 2000 gateway revenues. Jetstream manufactures a voice gateway, IAD and software called JetVision that manages the components of the packet-based network.

The Infonetics report examined shipments of voice-over-broadband gateways, such as the Jetstream CPX-1000 broadband voice services platform. More than 40 CLECs and integrated communications providers (ICPs) are rolling out service based on the platform, as well as the Jetstream Jetvision management software and IADs for deployment in their networks.

Figure 1: Jetstream Communications’ Voice-over-Broadband architecture.

Jetstream, which was founded six years ago, started out by building a CPE device that was based on ISDN technology. When that market crumbled, the company turned to making products for DSL. It was reportedly the first to debut the concept of VoDSL and it has a patent on the technology, says Eric Warren, the company's director of corporate communications.

Warren attributes Jetstream's market leading status in VoDSL equipment sales to the fact that the company was in the VoDSL market first, working with customers to refine the equipment. Jetstream was also one of the first companies to receive four ISO 9001 certifications for its equipment.

Some of the service providers using Jetstream's equipment include Access Point, Advanced Telcom Group, Edge Connections and Pine Tree Networks, an ILEC based in Maine.

Pine Tree chose to deploy Jetstream Communications' CPX-1000 broadband voice services platform as part of its deployment of a "state-of-the-art" voice and data network in Portland, South Portland, Lewiston, Auburn, Westbrook, Windham, and Scarborough, Maine, says Trevor Jones, Pine Tree's sales and marketing manager. The company is in the beginning stages of launching its voice-over-broadband services and expects to do this over the next two to five years.

Even though Jetstream is known for manufacturing voice-over-broadband equipment, it also makes software that enables the equipment's functionality. "We sell hardware, but our expertise is in developing the software that runs on that hardware," says Warren.

Another company that has seen rising sales of its VoDSL equipment is Lucent Technologies. By measure of voice ports shipped, Lucent was the largest vendor in the VoDSL market in the fourth quarter of 2000, according to the Dell'Oro Group. Likewise, Synergy Research Group ranked Lucent number one in the IAD market by measure of both revenues and units shipped.

Lucent Stinger DSL Access Concentrator

Lucent manufactures several VoDSL products, including the Stinger DSL Access Concentrator, PathStar Access Server, an IAD and a switch product. The company is also using third-party products from CopperCom and Jetstream.

"What we've announced in terms of our success in the marketplace is on the IAD side," says Bruce Miller, Lucent's senior product manager for second-generation products. "If you're purchasing the IAD, you're basically planning on doing voice for that customer."

About 90 service providers worldwide are deploying Lucent equipment, says Miller. Like other VoDSL vendors, Lucent has a partner program called "Wired for DSL" that helps ensure interoperability with the company's equipment. More than 20 CPE vendors and four or five gateway vendors have been qualified through this program.

In spite of that, the technology still has a way to go before it's ready for prime time. "DSL is a standard, but it is still an emerging technology, so it's not proven yet that you can just buy any device, plug it in and it works," says Miller.

State of VoDSL

Other VoDSL vendors include TollBridge Technologies, a three-year-old company that manufactures IP-based voice systems, including local exchange gateways and management software; and Accelerated Networks, a four-year-old manufacturer of IADs, concentrators and voice gateways.

Spokesmen from both companies share similar views on the state of the VoDSL industry. "VoDSL has a long way to go to achieve the status (of POTS telephone service)," says Kevin Woods, vice president of product management for TollBridge. "It took us 50 years to get (POTS) perfected."

"(VoDSL) still has a ways to go before it explodes," agrees Fima Vaisman, VP of marketing for Accelerated Networks. "The issues today are not technical; they're business oriented." Back office provisioning is one of the business issues holding back VoDSL, says Vaisman.

Will VoDSL hit pay dirt?

The Cahners In-Stat analysts agree with the guarded outlook on the VoDSL industry. "Unfortunately, VoDSL quality of service (QoS) hasn't yet reached traditional voice service levels, though by mid-year, significant progress may be made," says Ernie Bergstrom, senior analyst for Cahners In-Stat. "If these hurdles are overcome, VoDSL will begin to grow significantly in the third quarter of 2001, resulting in over 10 million active VoDSL lines in the U.S. by 2004."

In order for VoDSL to become successful, according to the analysts, some strategic imperatives will need to happen, including: The residential market should not be ignored, because that's where most of the DSL lines have been going; operators should not try to deploy VoDSL when DSL is still having deployment problems; and providers should not use a single technology like ATM or IP.

"The smaller CLECs and other people that compete with the RBOCs are going to be the people on the bleeding edge of implementing VoDSL because the RBOCs don't want to cannibalize their existing business model," says Bogen.

Internationally, VoDSL has a good chance of being implemented, says Bogen, because there isn't as much competition from cable as there is in North America.