When voice and data collide: Going live with voice traffic over packet networks

Data is the word of the future, but as many carriers know, voice represents income for both the present and the future. So what are carriers to do with the lower revenue generating data traffic? Find a way to bring it together with the lifeblood of voice.

Carriers have been leery of committing their voice traffic to technologies that may lack toll quality of service (QOS). But now, some are taking the leap by running voice traffic over packet networks.

"The [incumbents] have a problem in that now, for the first time, their Achilles' heel is their entrenched networks, whereas the new service providers and competitive local exchange carriers are taking advantage of new technologies like ATM," said Mike Simmons, product manager for Nortel Networks' Passport 8780 packet voice gateway. Many carriers are still using voice to pay the freight for the data, he said. "The challenge is to transition from the voice networks that we know and love today to data networks optimized for carrying voice," he added.

Next generation service providers GST Telecommunications and Westinghouse Communications Business Markets, a division of RSL COM, are deploying the Passport 8780 packet voice gateway. Both providers have central office switches with ATM networks in between, where the voice gateway will be deployed.

"A lot of the next generation carriers view ATM as the practical way to roll out voice services," said Ron Westfall, research analyst with Current Analysis.

Westinghouse, which provides telecommunication services in metropolitan areas around the United States, intends to use the Nortel product to cut facilities costs. By combining voice and data services and integrating them cost effectively, the Passport 8780 can save up to 66% of bandwidth compared with time division multiplexing networks, depending on how the network is engineered, Simmons said.

Although Westinghouse's president was confident in Nortel's product, he was a little more conservative with his estimates. "We are really not at the point to verify a 66% savings. We think it will save us around 35 to 40%, which is still significant," said Jim Kohosek, president and general manager of Westinghouse.

Westinghouse has separate backbones for voice and data, which it wants to migrate into a fully meshed ATM backbone using the Nortel product. Moving in that direction, Westinghouse is running a test between its Pittsburgh facility and Dallas node. The ATM adaptation layer-2 (AAL2) standards-based bandwidth compression of the product will help bring down facilities' costs, Kohosek said.

"AAL2 has yet to be deployed on a vast scale," said Jennifer Pigg, an analyst with The Yankee Group. "Although Nortel has been the first to speak, Lucent's PathStar access server represents a better price proposition." General DataComm has products that support AAL2, she added.

McLeod USA, KMC Telecom and FirstWorld Communications are using Lucent's PathStar access product for voice and data convergence.

"We are struggling to understand why Nortel thinks they are first in this area because we can think of at least two products in a similar category that are shipping - one an Ascend product and one a Lucent [product]," said Kathy Meier, general manager of IP communications for Lucent. Carriers have been pushing vendors for products with reliability, performance and toll quality voice, said Meier.

"The PathStar access server brings [public network] traffic into the CO and then sends it out in packets," she said. The product is targeted toward emerging carriers, added Meier, who also pointed to Lucent's Max TNT. That product is part of a voice-over-IP product line based on Ascend's remote access server, which came with the Ascend acquisition.