BT has launched its first Ethernet Virtual Private LAN service, one of three Ethernet-based services of the telco's 21st Century Network (21CN) project promised for this summer.

BT EVLAN, as the service is called, is a VPLS-based, any-to-any metropolitan service designed as a lower-cost alternative to private lines.

Ethernet was developed 30 years ago as a local-area network (LAN) technology, but recently telcos have been rolling out Ethernet LAN services on a city-wide basis, connecting offices within a metropolitan area with the simplicity of a single LAN.

In addition to business services, Ethernet is also being deployed as a backhaul technology for Wi-Fi and triple-play services.

Such networks allow companies to mix voice and data traffic using Internet Protocol (IP), and are more flexible and cost less than traditional private lines. For example they allow customers to specify the bandwidth required - EVLAN offers access speeds from 10Mbit/s, 100Mbit/s and 1Gbit/s. The open IP-based environment means companies can choose to manage their own IP layer, or have BT do it for them.

The service is initially available only in London, but will be rolled out in more UK cities later this year, BT said.

The company has made Ethernet central to 21CN, the IP-centric refurbishment of its network. Besides EVLAN, BT this year is rolling out BT GigaStream, a low-cost, point-to-point Ethernet private circuit service available nationally, and an enhanced version of BT Enterprise Ethernet.

Ethernet wasn't designed for telecoms, and thus lacks some of the carrier-grade features expected from traditional telecoms technologies. At this week's Carrier Ethernet Forum in Berlin, Nan Chen, president of the Metro Ethernet Forum (MEF), reportedly described Ethernet as the "cheapest, good-enough technology" on the market, saying that's just the sort of technology that ends up dominating.

Earlier this summer, BT CTO Matt Bross acknowledged Ethernet's shortcomings, but promised that it is advancing quickly, and will soon reach carrier-class security and resilience, end-to-end fault and performance monitoring, error location and remote configuration features.

The market for Ethernet services is expected to explode in coming years. The worldwide market for Ethernet services was US$2.5 billion in 2004 and is expected to more than double this year, according to Infonetics Research. From there, Ethernet service revenue is expected to jump another 276 percent by 2009 to $22.2 billion.

MEF this week awarded 39 metro Ethernet products from 16 vendors such as Alcatel, Lucent and Nortel its Carrier Ethernet Certification approval, a step towards reassuring carriers that the technology is interoperable and ready for the mainstream.

Other bodies providing interoperability standards for metro Ethernet include the International Telecommunications Union and the Institute of Electrical and Electronic Engineers.