AT&T is beefing up its ATM service with technology that will offer customers a more cost-effective way to support time-sensitive traffic
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The telecommunications giant is deploying Lucent's CBX 500 Multiservice WAN switches in its ATM network, which supports a relatively new ATM Forum specification called real-time variable bit rate (RT VBR).
The new technology will let users send voice and video traffic across their wide-area ATM networks at more economical rates than they could by using traditional constant bit rate (CBR) methods.
The primary difference is that RT VBR will let customers use shared ATM bandwidth that's engineered to reduce delay instead of using CBR, which is essentially a dedicated circuit over a service provider's network, says Mark Heaton, an analyst with TeleChoice, a consulting firm in Boston.
The specification eliminates the need for a carrier to dedicate bandwidth to every customer, which lowers costs for the service provider and users, Heaton says.
Multiple users can share the same ATM bandwidth using real-time VBR, which is not an option with CBR.
"More customers are asking for voice quality that doesn't have to go over the network as CBR traffic and has to be better than standard VBR," says Michael Kruswicki, ATM product manager at AT&T.
"The benefit is that we can slightly oversubscribe RT VBR because of the voice-compression algorithms in the specification,"Kruswicki adds.
Pricing a factorWhile AT&T will be ahead of the technology curve as it rolls out support for the enhanced ATM specification, TeleChoice's Heaton notes that pricing will be key to customer adoption. Customers haven't been very receptive to usage-based pricing, so AT&T should be coming up with some kind of flat-rate fee, he says.
AT&T did not reveal pricing schemes or specific service availability dates.
AT&T's ATM network, which was predominately built with Cisco BPX ATM switches, is now being populated with Lucent's CBX 500 switches.
The service provider is using the new gear to not only support RT VBR, but also to support higher bandwidth services to customers.
AT&T is now supporting OC-12 ATM connections to business customers using the CBX 500 switches, which offer more flexibility for high-bandwidth links, Kruswicki says. "The [user network interface] ports can support up to OC-48 connections in the network," he says.
AT&T has one financial customer using the OC-12 services today, but the service isn't officially available until early next year.
