Worldwide sales of metropolitan Ethernet equipment rose 27% last year to $13 billion, and Infonetics Research is forecasting the market to continue growing at double-digit rates over the next four years.

Infonetics says that each year, more Ethernet equipment is being deployed by carriers where SONET/SDH or ATM equipment was previously installed. Worldwide metro Ethernet ports reached 40.5 million last year.

In fact, by 2012, the majority of access and aggregation equipment that carriers are installing around the world will be based on IP, Ethernet and wave division multiplexing, rather than SONET/SDH, according to the research firm.

Adding to the weight of the prediction is the fact that many carriers are conducting interoperability tests on "all sorts of Ethernet products," Infonetics says.

Infonetics also predicts that sales of Ethernet access devices will nearly quadruple from 2007 to 2011; leading that market are ADVA Optical, RAD Data and Adtran.

Routers, carrier Ethernet switches, Ethernet over DSL, and Ethernet over optical are the hottest-selling technologies. But Infonetics says the fastest-growing metro Ethernet technology is Ethernet microwave, which is used to support mobile backhaul. Infonetics notes that Ethernet microwave is used for at least 55% of the mobile backhaul connections in the world.

The research firm also notes that the Americas aren't adopting Ethernet in the metro area as fast as other parts of the world. Asian service providers in particular are embracing the technology with gusto. China is laying fiber all over the place; its spending is a full 43% of the $3.4 billion spent on optical hardware in 2007 by Asia Pacific countries.