100 Gigabit Ethernet: Bridge to Terabit Ethernet
- — 22 April, 2009 09:03
Zimmerman says 10G is just now taking off in the access layer of large networks and will eventually move to the client side, creating the need for 40/100G in the distribution layer and the network core.
He says the application of 100 Gigabit Ethernet in the core is imminent, and is about two years away in the distribution layer. "Both will be driven by and drive 10G adoption in the access and client end of the network, where today the numbers are still much smaller than the potential," he says.
Spec designed for seamless upgrades
The 802.3ba specification will conform to the full-duplex operating mode of the IEEE 802.3 Media Access Control (MAC) layer, according to the task force. As was the case in previous 802.3 amendments, new physical layers specific to either 40Gbps or 100Gbps operation will be defined.
By employing the existing 802.3 MAC protocol, 802.3ba is intended to maintain full compatibility with the installed base of Ethernet nodes, the task force says. The spec is also expected to use "proven and familiar media," including optical fiber, backplanes and copper cabling, and preserve existing network architecture, management and software, in an effort to keep design, installation and maintenance costs at a minimum.
Even though the 802.3ba standard is not expected to be ratified until June 2010, initial interoperability testing will commence later this year, says Brad Booth, chair of the Ethernet Alliance. Public demonstrations will emerge in 2010, and certification testing will start once the standard is ratified, Booth says.
The specification and formation of the 40/100G task force did not come without some controversy, however. Participants in the Higher Speed Study Group (HSSG) within the IEEE were divided on whether to include 40G Ethernet as part of their charter or stay the course with 100 Gigabit Ethernet.
After about a month though, the HSSG agreed to work on a single standard that encompassed both 40G and 100G.
"In a sense, we were a little bit late with this," D'Ambrosia says. "By our own projections, the need for 100G was in the 2010 timeframe. We should have been done with the 100G (spec) probably in the 2007-08 timeframe, at the latest. We actually started it late, which is going to make the push for terabit seem early by comparison. But when we look at the data forecasts that we're seeing, it looks to be on cue."
Driving demand for 40/100G Ethernet are the same drivers currently stoking 10G: data center virtualization and storage, and high-definition videoconferencing and medical imaging. Some vendors are building 40/100G Ethernet capabilities into their products now.