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Predictions For 2002 Special Feature

[December 19, 2001]

VoDSL In 2002: Dead Or Alive?

By Ken Cavanaugh

The demise of many of the most aggressive broadband CLECs and the lack of public announcements by large carriers have made many in the industry question the progress of voice over DSL (VoDSL) this year. But it is during the quiet following the storm of hype surrounding voice over DSL that we are seeing the first real progress that will result in mass deployment of this technology. The standards and interoperability progress made to date have ensured that VoDSL did not sputter out before it got started.

Much of the progress made was done through a coalition of companies called OpenVoB. OpenVoB was formed to accelerate the adoption of voice over broadband. The group -- made up of silicon, IAD, gateway, and softswitch vendors -- is dedicated to enabling multi-vendor interoperability based on existing and emerging standards for voice over broadband. Leveraging existing and emerging standards, OpenVoB members were able to tackle some of the most challenging VoDSL technical issues head on.

The Year In Review: VoDSL In 2001
This time last year, the majority of voice over DSL solutions available were proprietary. These early solutions enabled several data CLECs to begin testing voice over DSL, however the technology's adoption by larger carriers was limited because they were unwilling to deploy another proprietary solution in parallel to the proprietary telecom architecture they already had in place. The ATM and DSL Forums standardized Class 5 derived voice over DSL in the form of the Loop Emulation Standard. The availability of this standard, and the support of the large carriers, made it possible for a host of vendors to begin implementing standards-based solutions for voice over DSL.

End of story, right? So why didn't VoDSL take off like a rocket? The problem begins with interpretation of the accepted standard. Each vendor's unique interpretation of the standard often results in very limited interoperability between vendors. In order to encourage service providers to test and ultimately deploy voice over DSL technology, the vendor community had to furnish service providers with evidence that any-to-any interoperability based on standards was not only possible, but also already tested and available.

The first step was to select a baseline set of implementation profiles for the Loop Emulation Standard. Once selected, members of OpenVoB created a test plan which it then executed at the University of New Hampshire in a series of interoperability events. Silicon, IAD, and gateway vendors worked together to establish a baseline of any-to-any interoperability. The outcome was the first publicly available implementation guide for the Loop Emulation Standard.

This document, which allows public access to the methodology of the standard's implementation, significantly increases the probability of multi-vendor interoperability, lowers the individual vendors' cost to test interoperability, and offers service providers a guarantee that the standards-based products, implemented to the test plan, will in fact work together. (Visit www.openvob.org to download the complete implementation guide).

The significant progress made culminated in a public multi-vendor interoperability demonstration in April 2001. What took years for DSL equipment manufacturers to accomplish from an interoperability perspective was proven out in the VoDSL market in less than one year.

These efforts resulted in the acceleration of lab and field trials of voice over DSL technology by large carriers, allowing them to move to the final stage prior to mass deployment: operationalization. This behind-the-scenes work, while not as visible as other stages in the market's development, is a true indicator that voice over DSL is moving beyond the hype.

Looking Ahead: VoDSL In 2002
Mass deployment in 2002 relies on several factors. First, a business case has to be made for the technology. The cost structure of the equipment and network architecture cannot exceed what exists today, and the technology must deliver tangible benefits to the service providers' customers, including lower costs, new services and increased flexibility.

Second, the regulatory environment has to encourage competition without eliminating incentives for incumbent providers to deploy new services and architectures. Voice services have always lived in the regulatory domain, and incumbent carriers are very wary (from a regulatory perspective) of mass deploying technology that marries the voice and data world without a clearer understanding of what the impact will be on the bottom line.

Finally, there are still technical hurdles to overcome as service providers begin the long and difficult process of operationalizing voice over DSL into their network. Two of these hurdles include flow through provisioning, and softswitch-based voice over broadband.

Flow Through Provisioning
Flow through provisioning enables service providers to automate the provisioning of new services, eliminating costly, time-consuming, and error-prone manual processes while enabling them to benefit from the revenues generated by customer access to on-demand services. Voice over DSL is a losing proposition if it relies strictly on manual processes -- the costs are prohibitive and the services can't scale.

The ATM Forum's Management Information Base (MIB) for CPE management using the LES Embedded Operations Channel, which went to final ballot at the ATM Forum meeting in July 2001, will enable service providers to auto-provision customer premise equipment through the voice gateway EMS, or Element Management System. This capability, once tested in a multi-vendor environment, dramatically simplifies the provisioning process, eliminating unnecessary complexity in the network, and lowering the overall costs of deploying VoDSL service.

Softswitch-Based Voice Over Broadband
Service providers intend to not only deploy derived voice services from a Class 5 network, but also from networks based on emerging IP and softswitch technology.

As a result, the ability to deploy voice over broadband technology using softswitch-compatible IP signaling and media protocols is critical to its acceptance as a strategic platform for service providers' long-term deployment plans. OpenVoB has created a test plan to begin the early stages of interoperability testing for voice over DSL based on existing and emerging Multiservice Broadband Network (MBN) standards for access networks. The group's intention is to focus on the problem of toll-quality VoIP over the "last mile."

Dead Or Alive?
Voice over DSL is alive and well. While the technology has not ramped up as quickly as hoped, the inherent complexity associated with changing decades of circuit-switched voice made it impossible for VoDSL to become an overnight sensation. However, the migration from circuit to packet in the service providers' networks is very real, and voice over DSL plays a starring role in that transition.

2002 will be a very important year for vendors to provide service providers with the mature, standards-based, proven technology required to seamlessly integrate voice over DSL into existing networks for mass deployment.

Ken Cavanaugh is director of business development at General Bandwidth and the chairman of OpenVoB.

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