If a big incumbent carrier wanted to roll out Ethernet services to business customers today, what infrastructure would it use -- Multiprotocol Label Switching (MPLS), next-generation Sonet (Synchronous Optical NETwork) and SDH (Synchronous Digital Hierarchy), or pure Ethernet?

The answer in the case of BT Group plc (NYSE: BTY; London: BTA) is none of them. It’s opted for rolling out Ethernet services over its existing Asynchronous Transfer Mode (ATM) network, according to an announcement today (see BT Picks Alcatel for Ethernet).

BT appears to have three very good reasons for making this decision. It will be easy and fast to accomplish, it enables BT to ensure the reliability and manageability of services, and it avoids taking risks with new technology that BT is still evaluating.

On the first point -– speed and simplicity -– all that BT has to do to offer Ethernet services is to add cards to existing equipment in its so-called MultiService Intranet Platform (MSIP), a 126-node nationwide ATM network based mainly on equipment from Alcatel SA (NYSE: ALA; Paris: CGEP:PA).

"We needed to get into the market quickly because we were losing business by not having a service, so we've equipped our Alcatel 7470s [multiservice platforms] with Ethernet cards," says Mick Palfrey, BT's MSIP manager.

"This was a quick and easy way to get into the market, but it's by no means the only way we'll offer Ethernet services. We're looking at other options at the moment that will give us a lower cost-per-port, and allow us to offer point-to-multipoint services, which requires more intelligence in the network," Palfrey adds.

Key to BT's requirements is the reliability and manageability of the service, a point previously made by BT Wholesale's strategy manager, Matthew Thomas, at a Light Reading Live! event in Geneva last October (see Monster Metro Ethernet Project Unveiled).

And that's one advantage to the way the current service is offered, says Palfrey. Because the Ethernet service is one of many data services running over the ATM platform, "there's already a very good network management system in place, and it's better than anything you'd get in the IP networking world. So we didn't have to add anything to provision and manage the service, just update some of the automation information to the existing OSS system and provide a little bit of training to the network management team. But it uses the same GUI [graphical user interface] as the other services with drag, drop, and click capabilities, and it uses the same automated systems for service building, managing, billing, and so on."

BT's point-to-point Ethernet service became available late last year and has generated "a lot of interest from companies wanting to know more about the service," says Palfrey, although no customer figures are yet available.

The service offers access speeds between 10 Mbit/s and 1 Gbit/s, according to the carrier's marketing literature. This also claims that a point-to-multipoint service is already available. Palfrey says it isn't and there's no set time for it to be delivered either.

— Ray Le Maistre, International Editor, Boardwatch