Enter the Metro Ethernet Forum New Ethernet standards and specifications from the MEF are virtually complete. The MEF's E-Line and E-LAN standards are being voted on, and will be finalised in August. "Until now, metro networking has come at the cost of of a major step change from Ethernet to more expensive, less familiar and less flexible technologies like ATM or Sonet/SDH," said Chen. "All that is set to change with the advent of carrier-class Ethernet services and transport." The analysts seem to agree. "In the next 10 years, Ethernet will inexorably take over the metro," stated Michael Howard, principal analyst and co-founder of Infonetics Research. "Of course, there will never be a wholesale change because of the Sonet/SDH installed base, but every year Ethernet will account for a larger portion of metro capital expenditure." Howard predicts a $5.7bn market for metro Ethernet hardware in 2006. The services market could be even larger. "Even where overall spend is flat or reducing, the metro area is where [telcos'] budget is focused," said Ian Keene, VP and chief analyst for the Gartner Group. Telcos working towards an Internet Protocol (IP) based infrastructure for services will have to spend what money they have on the metro, he said. Gartner predicts a $14bn market for metro Ethernet services in 2006. Talking the telcos' language The MEF specifications are designed to give service providers things they understand, and present services that can be sold to users. The standards include "Ethernet virtual circuits", very much like virtual circuits on ATM networks, and service specifications that will give users the familiar "committed information rates" and "peak information rates" they get with existing telco services. The standards will be referenced by the telco standards body, the ITU (International Telecommunications Union) -- in itself a very big indication of Ethernet's arrival in the telecoms area. Previous Ethernet specifications have been handled by the IEEE's local area network committees. Making it resilient - a faster spanning tree A major effort has been put into making metro Ethernet resilient. Sonet networks are up and running again within 50ms of any malfunction, because interruptions to voice calls are very noticeable. Traditional Ethernet networks recover more slowly because of the "spanning tree algorithm" they use to re-map and optimise the network paths. MEF proposes that metro Ethernet should use a local algorithm to divert traffic along detour paths within 50ms. When the global algorithm catches up and optimises the whole network, these detours can be replaced by more optimised paths if necessary. "It is not efficient if, when the network fails, it stops forwarding traffic while it calculates a new way to deliver it," said Chen. "The local recovery method mechanism may not be optimised, but Layer 3 mechanisms can detect the best path in time." The drafts of the MEF specifications are already being implemented by product vendors, and a test suite is being developed so service providers can be sure that they are getting standard products. As the products emerge, users should see that end-to-end Ethernet services between locations will be cheaper and more flexible than before.