By Jim Duffy, Network World | July 8th, 2014
25 Gigabit Ethernet Consortium formed with Arista, Brocade and Mellanox for faster development of lower cost/gigabit data center links.
Cisco is considering joining a handful of companies, including Google and Microsoft, that have defined a specification for 25Gbps and 50Gbps Ethernet for data centers requiring greater than 10/40Gbps.
The companies, which also include Arista Networks, Broadcom and Mellanox, have formed the 25 Gigabit Ethernet Consortium to promote standardization of the 25/50G Ethernet speeds and product development. The consortium is open to any interested company or organization, the companies said.
Cisco plans to join once it completes review of the application process.
“Cisco is reviewing the Consortium’s Adopter Agreement, and plans to join as a member after the review is complete,” a company spokesperson stated in an e-mail to Network World.
The consortium has received applications or interest from another five to 10 companies since its introduction last week, says Anshul Sadana, senior vice president of Customer Engineering at Arista.
Participants in the 25 Gigabit Ethernet Consortium will develop technologies in accordance with the consortium’s 25/50G specification. Products developed to it are intended to scale network bandwidth to cloud server and storage endpoints, where workloads are expected to surpass the capacity of 10/40G Ethernet links deployed today.
Products compliant with the consortium specifications are also expected to lower the cost per gigabit and power consumption of these links.
“It’s the sweet spot of the lowest price per gigabit,” says Sadana.
The companies say they formed the consortium to support an industry standard, interoperable Ethernet specification for those speeds between a server NIC and a top-of-rack switch. The IEEE is not involved in the consortium or its 25/50G specification, having standardized 10G and 40/100G, and beginning work on 400G Ethernet.
The companies say the motivation for founding the consortium is to immediately set an industry standard definition of the 25G and 50G Ethernet physical layer (PHY) and media access control (MAC) layer behavior, including virtual lane alignment, autonegotiation, and forward error correction characteristics; and to enable the swift rollout of 25G and 50G Ethernet compliant implementations over the next 12 to 18 months through the participation of multiple semiconductor, networking equipment and interconnect vendors.
IEEE standards can take years to develop. Four hundred gigabit Ethernet isn’t expected until 2017 even though work began on it last year. It took 12 years for 10G Ethernet to unseat Gigabit Ethernet as the predominant Ethernet networking technology in the data center; and the 40/100G 802.3ba standard was ratified in 2010, almost four years after the formation of a 100G High Speed Study Group that eventually acquiesced to demands to also include 40G.
“We can’t simply wait for that to happen,” Sadana says, who adds that an IEEE Call For Information (CFI) on 25/50G last March did not generate enough interest. He adds that 25/50G products will be backward and forward compatible with 10, 40/100, and 400G Ethernet products because they use the same IEEE 802.3 frame format.
IEEE did not comment by press time. Cisco says another CFI is planned for the next IEEE plenary meeting July 13-18.
“Cisco believes that 25G Ethernet needs to be standardized and that IEEE is the right forum for standardization,” the spokesperson says in the e-mail. “In the past Cisco has worked through IEEE with other industry leaders to standardize 1GbE, 10GbE, 40GbE, and 100GbE. Many other industry players, including some from the Consortium, are active participants in the preparations for the upcoming meeting and will state public support for the IEEE 25G standardization effort. Cisco also agrees with the 25G Ethernet Consortium on the value of promoting standardization and improving Ethernet Interfaces.”
The consortium’s specification prescribes a single twinax copper wire lane 25Gbps Ethernet and dual-lane 50Gbps Ethernet link protocol. The specification is being made available royalty-free by the consortium members to any data center vendor or consumer who joins the consortium.
The cost and power reduction per gigabit are due to the lower number of lanes 40G uses four 10G lanes 25/50G requires. Twenty-five gigabit products will not cost 2.5 times that of 10G, and 50G will cost less than 5x 10G, Sadana says.
The average selling price of a 10G fixed top-of-rack switch port in the first quarter was about $270, according to Dell’Oro Group. Dell’Oro believes 25G Ethernet will be a hot seller in the data center and may disrupt 40G’s penetration as a server access technology.
“Most 100G is just four lanes of 25G,” the market research firm states in its Q1 Ethernet switch market share report. “Thus, in supporting 100G, many components can be easily split to 25G. This could lead 25G to drive a better cost curve than 40G. If this occurs, despite not being a standard, 25G would likely spread beyond Microsoft,” which Dell’Oro says confirmed plans in Q1 to use 25G in its data center.
It may spread to Cisco product development as well, Dell’Oro posits. Cisco and Arista are suppliers of top-of-rack switches to Microsoft data centers, which have the second largest installed base of servers.