Interoperability Will Accelerate Deployment Of Voice Over Broadband

BY BRIAN HENRICHS

The transformation from circuit-switch to packet-switch voice will be the next great communications revolution. What the Internet did for data communications, broadband will do for voice. The flurry of development surrounding broadband delivery of voice services is evidence of the beginning of this transformation to packetized voice.

Packetized voice leverages packet-switched networks to deliver voice calls over ATM, IP, or frame relay. Originally conceived as a toll-bypass application, the maturation of broadband technology and the growing deployments of these technologies for high-speed data applications has turned the attention of CLECs, ILECs, cable operators, and other service providers towards the potential for packetized voice delivery, as well. Voice over broadband utilizes a high-speed connection to deliver multiple channels of toll-quality, packetized voice over a single broadband pipe. This dramatically improves the revenue potential of the single connection, and opens up a new world of service opportunities based on the array of development surrounding packet-based applications.

The Delay In Voice Over Broadband Adoption
While there is a heightened sense of awareness and a broadening interest in the tremendous potential for voice over broadband, carriers have been slow to convert from trials to actual network implementation of the technology. A number of factors are contributing to this delay:

• Predominance of proprietary, closed systems;
• Lack of a clear migration path to future generations of network architectures;
• Limited availability of true carrier-class voice gateways designed for mass deployment; and
• Lack of support for the interoperability of multiple access points (DSL, cable, wireless) and multiple network topologies (ATM, IP, frame relay).

These barriers to the adoption and deployment of voice over broadband by service providers demand a concerted industry effort to leverage the work of standards bodies to enable open, interoperable, multi-vendor implementations. Easy enough, right? So why has so little progress been made up until now on standards-based interoperability?

The Interoperability Challenge
At the core of the interoperability challenge is the self-perpetuating reliance of the telecommunications industry on proprietary technologies. In an effort to squeeze out as much performance and capacity as possible, equipment suppliers and service providers have often leveraged proprietary technologies that compromise standards of network interoperability. The immediate demands of individual applications have taken precedence over long-term implications for the network as a whole, and the cumulative effect has been a limitation in how quickly the legacy network can evolve to incorporate new infrastructure, applications, and services.

Why would vendors encourage this kind of environment? There are trade-offs to contributing to standards, and building hardware based on those standards. Vendors face more competition, and must continually work to improve their technology to keep their customers. As a result, many vendors have base their products on the old telco model of proprietary end-to-end systems. Service providers, and their customers, are the losers in this scenario. Proprietary solutions require a great deal of resources to enable multi-vendor solutions, and ultimately slow the adoption of the technology.

So what does a standards-based approach to voice over broadband mean? It means supporting existing and developing standards and specifications; enabling multi-vendor solutions; and creating a platform for development and innovation that doesn't inherently limit the service provider's ability to migrate to next-gen communications infrastructure, services, and revenues. It also means enabling consumer adoption of the technology by creating a competitive environment that lowers the cost for consumer hardware and services -- bringing new technology to market in a way that is mass deployable.

Supporting A Unified Approach
The integration of voice and data networks will be the first proving ground of the next generation network. There is a tremendous opportunity to improve upon history by founding voice over broadband on open, interoperable, multi-vendor solutions.

Powerful applications like voice over DSL, voice over cable, and voice over broadband wireless can no longer be limited to proprietary hardware, fragmenting the market and slowing adoption. Voice gateways must be able to support the service provider's variety of access technologies (cable, DSL, and wireless), their varied customer base (business and residential customers), and natively support their existing and future network protocols (ATM, IP, and frame relay) -- all by utilizing existing and emerging standards. A unified approach towards voice over broadband gives the service provider a flexible and efficient way to deploy packetized voice services. However, offering this flexibility is no easy task from a product development standpoint. There are myriad standards associated with all of the above access networks and network protocols.

OpenVoB Works Towards Interoperability
Recently, a group of vendors that spans IAD (Integrated Access Device) vendors, softswitch vendors, and voice gateway vendors made available a technical whitepaper through an organization called OpenVoB. OpenVoB was created with the intention of bringing voice over broadband vendors together to support interoperability based on existing specifications being delivered through the ATM Forum, CableLabs, DSL Forum, and others. These specifications form a foundation for true interoperability between the various network elements in a voice over broadband network.

The whitepaper's sponsors, which include 2Wire, Accelerated Networks, AccessLAN, Broadband Gateways, General Bandwidth, Intel, IPCell, and Woodwind Communications, outlined specific implementation plans for voice over DSL and voice over cable network models. [Read the whitepaper as an Adobe Acrobat file.] The paper specifies an implementation roadmap that can serve as the baseline for true interoperability among multiple vendors. The architecture outlined is based on existing standards such as the ATM Forum's Voice and Multimedia Over ATM-Loop Emulation Service Using AAL2, CableLab's PacketCable Specification 1.0, and residential gateway control protocols, such as MGCP/MEGACO. These standards represent the leading open specifications for voice services over broadband systems.

From the roadmap architecture, vendors will be able to participate in OpenVoB sponsored "callfests" that will provide a centralized, open environment in which vendors can achieve interoperability with others' network elements. The goal is to enable multiple vendors to work together to implement existing and emerging standards, accelerating the deployment of voice over broadband services.

It is this type of open, multi-vendor approach towards voice over broadband that will guarantee service providers are no longer forced to perpetuate a pattern of investment in proprietary infrastructure. An open approach will guarantee that the work of the various standards organizations is leveraged through rapid implementation and interoperability testing. As a result, voice over broadband will be the driving force in the transformation of telecommunications.

Brian Henrichs is the Vice President of Business Development for General Bandwidth, Inc., a voice gateway manufacturer dedicated to delivering open, standards-based voice over broadband solutions. He may be reached at [email protected]. General Bandwidth enables toll-quality voice services to residential and business customers across emerging broadband access networks such as digital subscriber line (DSL), cable, and wireless. The company's voice over broadband gateway -- the G6 -- provides multiple derived voice lines over a single broadband connection, allowing service providers to offer packetized "last mile" voice services that meet and exceed the quality and functionality of today's POTS (Plain Old Telephone Service).