Circuit break: SBC takes on the challenge of packets

SBC Communications is trying to modernize its network for future demands by migrating voice traffic to packet-based rather than circuit-based networks. The move comes as Internet traffic continues to wreak havoc on networks accustomed to the average three-minute phone call.

SBC plans to use an ATM distributed network system architecture that will use voice trunking over ATM to transport voice traffic as it does data traffic - in packets. By implementing the new architecture, SBC hopes to increase efficiency, lower costs and improve scalability.

"We will begin putting in ATM switches rather than the tandem circuit-switched equipment," said Fred Chang, vice president of SBC subsidiary Advanced Solutions.

"One of the problems telephone companies have wrestled with is that it is very expensive to manage these interoffice networks because they are circuit-based," said Michael Arellano, a consultant with Degas Communications Group. By migrating new traffic to the ATM switches, costs will decrease and the trunk utilization will be optimized, Arellano added.

Rather than having many local switches connected by a much smaller number of tandem switches and circuit-based trunks, ATM interoffice networking converts traffic to ATM, which creates an ATM cloud to replace the tandem switches. Because ATM can allocate virtual circuits dynamically, physical trunks don't have to be dedicated physically to the switches, Arellano said. "You just have to make sure the ATM network has enough capacity overall to handle all the traffic between all the local switches at any given hour of the day."

"This is a really great idea for service providers [that are] not prepared to take the full leap into converged services but still need the benefits of a more efficient backbone," said Chris Nicoll, senior analyst at Current Analysis. "We will see more and more carriers doing this." The migration to ATM provides carriers with a far less complex and more efficient network to handle the increasing demands, he said.

SBC plans to begin field trials of the voice-trunking-over-ATM technology next year in Houston and Los Angeles, said Steve Dimmitt, vice president of consumer marketing for SBC.