The completion of Metro Ethernet service specifications in August this year may accelerate the take-up of the technology by telecoms carriers, leading to a wider range of cheaper, faster, more reliable wide area network (Wan) services becoming available to corporates.

Nan Chen, president of the Metro Ethernet Forum, said that the final standards will allow IT managers leasing Wan Ethernet links to get the guaranteed bandwidth that fledgling Metro Ethernet service providers are currently unable to offer.

Metro Ethernet bandwidth can be severely degraded when network congestion occurs, whereas rival ATM and frame relay over Synchronous Digital Hierarchy (SDH) technologies offer firms private virtual circuits - leased lines - which guarantee that the bandwidth will be available.

"The new [Metro Ethernet] specifications will allow carriers to provide guaranteed services, typically 50Mbit/s Ethernet connections, with burst rates to 100Mbit/s," explained Chen.

He said this would lead to cost savings, faster provisioning and flexible bandwidth management, allowing data rates to be scaled from 10Mbit/s to 1Gbit/s in 1Mbit/s increments.

"Monthly costs [for the customer] can be reduced by up to 50 per cent when you make a comparison with traditional leased lines such as E1s," said Chen.

"Also, customers can scale their bandwidth up and down themselves whenever they want, and there is significant visibility of service through tools that monitor the bandwidth."

Neil Fairbrother, marketing director at service provider Neos Networks, pointed out that firms leasing Metro Ethernet bandwidth install no additional equipment on site, and IT managers and administrators already understand and trust Ethernet technology.

"Most firms already have Ethernet on the local area network, and it's just a case of plugging in a cable to a port on their existing router," he said.

"Some routers do have to be replaced, but only where they are 10 years or so out of date."

Some telecoms carriers may be reluctant to scrap their legacy investments to move to Metro Ethernet, however, and many prospective customers are already tied in to lengthy leased line contracts.

Doubts also remain about Ethernet's suitability for carrying voice and video traffic over telecoms networks. ATM and frame relay over SDH are perceived to offer the better quality of service necessary to reduce latency that can render voice calls unworkable.

This situation has recently been improved with the construction of Multiprotocol Label Switching backbones able to carry Ethernet traffic, while Ethernet over SDH is allowing carriers to carry Ethernet packets over their existing optical networks.

Chen believes that carriers cannot avoid moving at least part of their infrastructure to Metro Ethernet in the future.

"The carriers know they have to develop new infrastructure to offer new services that are scalable," he said.