IEEE launches 25 Gigabit Ethernet Study Group

Having had a proposal for 25 Gigabit Ethernet specifications fail to reach a vote this past March due to a perceived lack of interest, the IEEE now has decided that 25 Gigabit Ethernet might be worth pursuing after all. The organization has announced the formation of the IEEE 802.3 25 Gb/s Ethernet Study Group, which will research market opportunities and requirements for a single-lane 25-Gbps version of Ethernet.

Having had a proposal for 25 Gigabit Ethernet specifications fail to reach a vote this past March due to a perceived lack of interest, the IEEE now has decided that 25 Gigabit Ethernet might be worth pursuing after all. The organization has formed the IEEE 802.3 25 Gb/s Ethernet Study Group, which will research market opportunities and requirements for a single-lane 25-Gbps version of Ethernet.

The desire for a 25-Gbps Ethernet specification has developed in light of the 4x25-Gbps options now available for 100 Gigabit Ethernet, as well as ongoing efforts toward specification of a 4x25-Gbps electrical interface. Large data center operators, particularly Microsoft, have espoused the need for a 25-Gbps Ethernet specification as a way to neatly aggregate server Ethernet interconnects at speeds greater than 10 Gbps into a 100 Gigabit Ethernet backbone. In the current Ethernet regime, the only data rate interval between 10 Gbps and 100 Gbps is 40 Gbps, which doesn’t neatly aggregate into a 100-Gbps pipeline and carries a significant cost premium over 10 Gbps.

A Microsoft representative presented a proposal for a 25-Gbps specification at an IEEE plenary last March, but the idea didn’t make it to a vote (see "Efforts toward 25 Gigabit Ethernet specs stall at IEEE plenary"). Undaunted, supporters of the idea formed the 25 Gigabit Ethernet Consortium to develop such specifications themselves (see "25 Gigabit Ethernet, 50 Gigabit Ethernet targets of industry consortium").

At a meeting last week, the IEEE reexamined the topic and created the Study Group.

"The application of single-lane 25-Gbps signaling technologies provides Ethernet with a solution set that can be reused by those companies building the data centers of tomorrow. The new study group expects to lay the groundwork for a new Media Access Control (MAC) rate that will enable cost-optimized single-lane solutions that will increase network deployment efficiency," said Mark Nowell, chair of the IEEE 802.3 25 Gb/s Ethernet Study Group and senior director, Cisco Systems, via an IEEE press release. "The heavy lifting in developing and standardizing 25-Gbps signaling technologies has been done as part of the development of 100-Gbps Ethernet. These technologies can be reused to enable a single-lane 25-Gbps Ethernet solution set for server interconnects for these future data centers."

The IEEE's willingness to investigate 25 Gigabit Ethernet isn’t a surprise to members of the industry consortium.

"Most members of the 25 Gigabit Ethernet Consortium are also participants in the IEEE group that approved the Call for Interest (CFI) for an IEEE standard for 25 Gbps virtually unanimously," said Kevin Deierling, vice president, marketing of 25 Gigabit Ethernet Consortium founding member Mellanox Technologies. "Mellanox supported the 25-Gbps Ethernet CFI and, while there are no guarantees, we will drive to see these two specifications converge to a single standard such as exists for 10, 40, and 100 Gbps Ethernet today."

More information on the IEEE Study Group can be found at http://www.ieee802.org/3/25GSG.

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