AT&T outlines migration to IP core

AT&T is investing $3 billion - virtually all of this year's capital expenditure budget - to facilitate its migration from a circuit-switched network to an IP packet-based one.

In moving to a single IP core using Multi-protocol Label Switching (MPLS), AT&T remains reluctant to put an expiration date on its old voice network.

AT&T already has decommissioned 130 circuit-switched platforms in the past 18 months, including switches, billing and provisioning systems, says Hossein Eslambolchi, AT&T CTO and president of AT&T Labs. The carrier says 140 more legacy systems will come offline by the end of 2005.

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AT&T is investing $3 billion - virtually all of this year's capital expenditure budget - to facilitate its migration from a circuit-switched network to an IP packet-based one.

In moving to a single IP core using Multi-protocol Label Switching (MPLS), AT&T remains reluctant to put an expiration date on its old voice network.

AT&T already has decommissioned 130 circuit-switched platforms in the past 18 months, including switches, billing and provisioning systems, says Hossein Eslambolchi, AT&T CTO and president of AT&T Labs. The carrier says 140 more legacy systems will come offline by the end of 2005.

The company has deployed 104 intelligent optical switches throughout its network. These switches support high-speed connectivity at the OC-192 (10G bit/sec) range and point-and-click, real-time bandwidth provisioning, Eslambolchi says.

One key step for AT&T will be deploying multi-service switches at the edge of its network.

"The battleground in the 21st century is about who has got the best network from edge-to-edge," Eslambolchi says. The carrier is testing two vendor devices and is close to making a selection, although he would not name the gear makers.

But the MPLS devices will support voice, video, IP, frame relay and ATM traffic. The carrier expects to start deploying multi-service edge switches early next year. Supporting MPLS at the edge and in the core will let AT&T offer guaranteed classes of service, which is still difficult to support today.

"Our objective is to try to evolve and we are much further along than what is perceived in the industry," Eslambolchi says.

AT&T is ahead of its prime competitors. MCI in April announced its plans to move to one IP network to handle all its voice and data traffic. MCI, legally known as WorldCom, says it has deployed 36 Nortel Passport Packet Voice Gateways in its effort to move at least 25% of its voice traffic over its IP core by year-end 2004.

But analysts pointed out when MCI made its announcement that AT&T and Sprint were already well underway with their plans to migrate to a singe IP core. AT&T's network is based on IP and MPLS and Sprint's network is based on IP and primarily ATM.

Although Sprint recently said it also will deploy MPLS in its network, the carrier still views MPLS as an edge technology and stands firm that it will not deploy MPLS at the core of its network.

The carriers also have to upgrade billing, provisioning and management systems while maintaining a high level of network performance.

"A carrier couldn't introduce strong [service-level agreements] around class of service...without having the back-end systems in place," says Lisa Pierce, an analyst at Giga Information Group. Back-end systems are necessary for a carrier to bill, provision and manage services across its network using these multi-service switches. Carriers, such as MCI that only have one piece in place, in its case the edge switches, likely would support only test traffic today, she says.

Eslambolchi says AT&T has invested $500 million in developing an "application-aware network," aimed at improving customer service and adding more flexibility to the network. The system will allow automatic circuit upgrades based on predefined customer parameters. The investment also is being used to improve "billing accuracy to 95%," he says.