Google caused a stir at ECOC by requesting a new 100 gigabit-per-second (Gbps) interface, claiming the existing 100 Gigabit standards fall short of what is needed.
According to a report by Pauline Rigby, Google wants something in between two existing IEEE interface standards. The 100GBase-SR10, which has 10 parallel channels and a 125m span, has too short a reach for Google.
“What is good for an 800-pound gorilla is not necessarily good for the industry. It [Google] should have been at the table when the IEEE was working on the standard."
Daryl Inniss, practice leader, components, Ovum
The second interface, the 100GBase-LR4, uses four channels that are multiplexed onto a single fibre and has a 10km reach. The issue here is that Google doesn’t need a 10km reach and while a single fibre is better than the multi-mode fibre based SR10, the interface is costly with its “gearbox” IC that translates between 10 lanes of 10Gbps and four lanes each at 25Gbps. Both IEEE interfaces are also implemented using a CFP form factor which is bulky.
What Google wants
Google wants optical component vendors to develop a new 100 Gigabit Ethernet multi-source agreement (MSA) that is based on a single-mode interface with a 2km reach, reports Rigby. Such a design would use a ten-channel laser array whose output is multiplexed onto a fibre, a similar laser array-multiplexer arrangement that has already been developed by Santur. Using such a part, the new interface could be developed quickly and cheaply, says Google.
The proposed interface clearly has merits and Google, an important force with an appetite for optics, makes some valid points. But the industry is developing 4x25Gbps interfaces and while such interfaces may be challenging, no-one doubts they will come.
Google’s next moves
Google has a history of being contrarian if it believes it best serves its business. The way the internet giant designs data centres is one example, using massive numbers of cheap servers arranged in a fault-tolerant architecture.
But there is only so much it can do in-house and developing a new optical interface will require help from optical component players.
Google has the financial muscle to hire an optical component firm to engineer and manufacture a custom interface. A recent example of such a partnership is IBM's work with Avago Technologies to develop board-level optics – or an optical engine – for use within IBM’s POWER7 supercomputer systems.
According to Karen Liu, vice president, components and video technologies at market research firm Ovum, once such an interface is developed, Google could allow others to buy it to help reduce its price. “Remember the Lucent form factor which became a de facto standard but wasn’t originally intended to be?” says Liu. “This approach could work.”
Taking a longer term view, Google could also invest in optical component start-ups. The return may take years and as the experience of the last decade has shown, optical components is a risky business. But Google could encourage a supply of novel, leading-edge technologies over the next decade.
The optical component industry is right to push back with regard Google’s request for a new 100 Gigabit Ethernet MSA, as Finisar has done. While Google may be an important player that can drive interface requirements, many players have helped frame the IEEE 100Gbps Ethernet standards work. In the last decade the optical industry has also seen other giant firms try to drive the industry only to eventually exit.
“The industry needs to move on,” says Daryl Inniss, practice leader, components at Ovum. “What is good for an 800-pound gorilla is not necessarily good for the industry.” Inniss also suggests a simple and effective way Google could have influenced the 100 Gigabit Ethernet MSA work: “It [Google] should have been at the table when the IEEE was working on the standard."