At last month's meeting of the IEEE study group exploring the possibilities of Energy Efficient Ethernet, the question of whether to define a standard for fiber optics came up.

So far, the group has largely concentrated its efforts on copper-based connections. The ability to change speeds in copper-based Ethernet is well established, and reducing the data rate can reduce power consumption. The group has even been throwing around the term "0Base-T" to describe a state where the link speed is zero on a copper link.

Is a fiber-optic equivalent possible or desirable? Onn Haran of PMC-Sierra raised that issue in a presentation posted on the study group's site, a slideshow that according to the minutes was presented by Brian Holden at the September meeting.

The presentation suggested that, while moving to slower speeds is usually not possible for optical components, the traffic could be paused for power savings. Transmit and receive functions can be turned off, eliminating power consumption by the transceiver, SERDES and MAC. Haran called the potential technique "zero-base-R."

However, the presentation also noted that returning from zero-base-R to normal operation - in a wake-on-LAN kind of function - would not be desirable, "since a substantial number of receiver optical components must remain active during sleep." So, a predetermined sleep period would have to be specified instead.

It appears that more study is needed to determine if and how power savings would be applied to fiber optics, but it is an interesting question.

Jeff Caruso is site editor at Network World.