100-GigE, 40-GigE Live in Peace

After months of internal squabbling, members of the Institute of Electrical and Electronics Engineers Inc. (IEEE) Higher Speed Study Group (HSSG) have finally agreed on a path to the next standard for high-speed Ethernet.

At a meeting last week, HSSG members approved the project authorization request (PAR) and the IEEE's "five criteria" required for the study group to continue working on a new Ethernet standard that will include both 40-Gbit/s and 100-Gbit/s rates. (See 100GE Gets OK'd.)

The agreement comes after six months of internal debates over whether the next standard should include a 40-Gbit/s line rate, and a full year after the study group was founded.

The new standard will provide physical layer (PHY) specifications to support 40-Gbit/s operation over at least 100 meters of multimode fiber, at least 10 meters of copper, and at least 1 meter over a backplane.

On the 100-Gbit/s side, the standard will address distances of at least 10 km and 40 km on singlemode fiber; at least 100 meters on multimode fiber; and at least 10 meters over copper.

The HSSG was formed to define the next Ethernet standard for network aggregation, and it seemed well on its way to advancing a 100-Gbit/s proposal late last year. (See 100-Gig Ethernet Takes First Step, 100-GigE Takes Shape, 100-Gig Ethernet Gets Official Nod, and IEEE Picks 100 GigE.)

But in January some members of the group, led by server and storage vendors such as Sun Microsystems Inc. , HP Inc. (NYSE: HPQ), and Brocade Communications Systems Inc. (Nasdaq: BRCD), began pushing for a standard that included a 40-Gbit/s rate for data-center applications. (See 40 GigE Could End Standards Spat.)

A number of switching and routing vendors, including Cisco Systems Inc. (Nasdaq: CSCO), rejected that idea, citing possible delays in the commercialization of 100-Gigabit Ethernet aggregation products, as well as the higher costs involved in developing and manufacturing products that comply with a dual 40- and 100-Gbit/s standard.

In the end, the group was able to secure a large enough majority to adopt the proposal for a dual standard. In the five-criteria document, the HSSG noted that "bandwidth requirements for computing and core networking applications are growing at different rates, which necessitates the definition of two distinct data rates for the next generation of Ethernet networks."

Specifically, a majority in the group decided that 40 Gbit/s provided "the best balance of performance and cost" for servers and computing applications, while 100 Gbit/s was the better speed for aggregation and core networks.

On the HSSG email reflector on Friday, study group chair and Force10 Networks Inc. components scientist John D'Ambrosia wrote that the IEEE 802.3 Executive Committee had approved the pre-submission of the group's PAR to the New Standards Committee (Nescom) for consideration at the December 2007 Standards Association Standards Board (SASB) meeting, and that it would remain on the agenda subject to Executive Committee approval at the November meeting.

D'Ambrosia also noted that the Executive Committee had approved an extension of the HSSG, allowing it to continue working on defining the standard.

Brad Booth, president of The Ethernet Alliance , says that, despite the internal debates, he doesn't expect much delay in the standardization process. "I would expect formal ratification sometime in 2010," he says. "The real technical meat of the work can start, and has already. We've seen presentations that are very technical in nature, so we may have a first draft by next summer, which would put us in line with where we hope to be"

Were it up to Light Reading readers, things might have gone differently. In an informal poll that had gathered 227 responses as of press time, 44 percent of those voting thought the HSSG should have stuck to only 100-Gbit/s Ethernet, while just 26 percent feel a dual 40-Gbit/s and 100-Gbit/s standard is in order.

Twenty-four percent called for separate 40-Gbit/s and 100-Gbit/s projects, while 6 percent believe only a 40-Gbit/s Ethernet standard is necessary. (See A 40-Gig Fiasco.)

— Ryan Lawler, Reporter, Light Reading