Recent activities on the standards front and in the technology demonstration arena show that momentum is building toward 400G at both the optical network and Ethernet levels. That makes sense at the end of a year during which 100G deployments and services have become much more common, though there is still a long way to go.
Last week, the Optical Internetworking Forum announced its "400G Framework Document" to analyze possible modulation formats, per-channel data rates, number of subcarriers and potential application scenarios, among other items. Technology demonstrations involving 400 Gbit/s also were featured prominently at last week's Super Computing 2013 conference. Many optical vendors already have made news this year with several demonstrations and lab tests of 400 Gbit/s for the public network. (See OIF Plans to Define 400G and Big Bandwidth Bolsters SC13.)
These moves came just days after the IEEE 400 Gbit/s Study Group updated its objectives for developing a 400 Gigabit Ethernet standard with recommendations for physical layer link distances of at least 100 meters over multi-mode fiber, and 500 m, 2 km, and 10 km over single-mode fiber. As with the study group's other 400 Gig-E standard objectives, these link distances have yet to be approved at the working group level.
It is likely that the IEEE standard for 400 Gig-E links will not be ready for another two to three years. However, research firm CIR notes in a new study of the service potential for 400 Gbit/s Ethernet services that "the addressable market for 400 Gig-E will be considerably larger than that initially targeted by 100 Gig-E," mainly because big data and related trends are forcing the construction of larger datacenters that will require much more bandwidth. CIR also says that some of the world's largest datacenters already use 400 Gbit/s aggregations and backbones to serve their needs.
As 400G optical networking and 400 Gig E progress, the prospects for 1 Tbit/s Ethernet are less certain. The IEEE had chosen to move forward with a 400 Gig-E standard separate from a 1 Tbit/s discussion largely because of the lack of economical methods for reaching 1 Tbit/s Ethernet, and not much has changed. For example, Ethernet Alliance Chairman John D'Ambrosia told Light Reading recently that the industry still lacks a 100G single-lambda, single-fiber solution that could help make 1 Tbit/s more economical. "If I go to 100 Gbit/s over a single fiber, it's easier to get to 1 Tbit/s, but the 802.3ba group didn’t reach consensus on that, so it's not at a good stage." (See Why the IEEE Picked 400G Over Terabit.)
— Dan O'Shea, Managing Editor, Light Reading