10/30/2007 -- Even though SONET/SDH remains the dominant transport for the metro segment, Ethernet is gaining fast. As a result, according to industry watcher Infonetics Research, Ethernet will eventually dominate the metro space, while SONET/SDH slowly declines over the next 10 to 20 years.

Infonetics isn't just pulling numbers out of its posterior, either. Its data is based on a recent survey of 27 top service providers in North America, all of which are already offering Ethernet services. What's more, service providers reported, their metro Ethernet service revenues are growing fast.

"The most telling finding in the study is that the vast majority of service providers we interviewed have a strategy for using Ethernet instead of SONET/SDH for accessing and collecting customer traffic," said Michael Howard, principal analyst of Infonetics Research, in a statement.

Service providers once opted for mature SONET/SDH technologies in place of what were perceived as comparatively immature Ethernet offerings. That's no longer the case, according to Infonetics.

"Ethernet as a carrier-class technology has made considerable progress," Howard said. "[A]lmost 90 percent of service providers participating in the study believe Ethernet is mature for carrier-class deployments, which is much different from the attitude of two years ago."

Elsewhere, Infonetics said, more than one-fifth of service providers have stopped (and over half have slowed) deployment of new SONET/SDH gear.

In addition, Ethernet transport tunnels will become essential ingredients of next-gen services and optical transport layers. And elsewhere on the tunneling front, both T-MPLS and PBT -- which are comparatively new technologies -- should see encouraging growth as VPN backbones by 2008.

Finally, more than 25 percent of survey respondents identify Ethernet tunneling protocols as critical (or must-have) features on the metro Ethernet equipment they plan to purchase next year. --Stephen Swoyer