The Industry Discussion – 100GbE over a Single Lambda!

By John D'Ambrosia


This week the Ethernet Alliance, along with its partner the OIDA, is hosting a workshop on June 12-13 at the San Jose Convention Center to explore 100 Gigabit Ethernet per lambda for data center applications.  (For more information on the agenda, please see http://bit.ly/1fNDC8q.  To register for the event, please see http://bit.ly/1kQIOab.)

The genesis of this workshop began last year as the Ethernet Alliance was in the formative stages of planning for its Technology Exploration Forum 2013, which explored the future of Ethernet.  Part of that event’s agenda was a panel discussion on the development of the next optical eco-system, which it was argued, would be based on 100 Gb/s lambdas.  After our experts gave a number of excellent presentations (find those at http://ethernetalliance.org/tef-2013-the-future-of-ethernet-presentations/), I posed the following question, “How many of you feel this is possible – regardless of the timing?”  Every member of that panel raised their hand in agreement but as discussion continued two things became evident.  First of all, there were a number of technical challenges and hurdles that needed to be addressed, which included further analysis on signaling / modulation schemes.  Second was the need for this solution, and how the development would be paid for.  The conversation elevated even higher, as people realized that this was an industry level discussion and decision.

The need for this week’s industry workshop was clear.

Such discussion however cannot occur in a vacuum and must take into account the state of 100GbE today.  Currently, 100GbE is mainly being serviced by 100GBASE-LR4 that multiplexes four 25 Gb/s lambdas over one single-mode fiber up to 10 km.  Soon, 100GBASE-SR4, with individual 25Gb/s VCSELs, will send single lambdas over four multimode fibers to 100 meters.  At the same time, a plethora of optical multi-source agreements, or MSAs, have come into existence as the industry looks to accelerate the adoption of 100GbE.  While many of us involved in the standardization process realize that we can’t second guess the market, I find the lack of a single clear direction to drive volume up and cost down for the data center space troublesome.

I remembered something that Bob Metcalfe said last year during one of the many of the 40th anniversary of Ethernet celebrations, “Sometimes you need transitional technologies – but that’s ok.”  Words of wisdom from the Maestro. 100GbE did need a 4×25 Gb/s configuration to progress the industry forward.  However, historically the industry has seen optical solutions in the Ethernet space transition to a serial, single lambda solution.  Therefore we do need to start considering this evolution. 

Some may say that this is already being accomplished, as we see 100GbE technologies being supported via a single wavelength in optical transport networks (OTN) today.   This is done on the OTN line side however, not the Ethernet side or client side connection, which is supported via a number of Ethernet solutions that are based on either parallel lambda or fibers.  Furthermore, we see 40GbE being aggressively deployed in data centers today.   I have always said that the economics of an application will drive the solution that gets deployed, and the cited deployments of 40GbE and 100GbE are perfect examples of this concept.

The need for the Voice of Ethernet to be raised is clear.  Discussions targeting the development of 100GbE over a single lambda for the data center space must begin as this will provide the industry with the long-term solution it needs.  So come be part of the discussion this week at the ‘100GbE per Lambda for Data Center Workshop’! 

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