FCoE and 10G Networks

Fibre Channel over Ethernet (FCoE) is a hot topic among network operations and data center circles these days. FCoE is seen as a key to convergence of the various technologies in the data center, so let’s spend a few minutes reviewing the concept, some expectations for when it will start to reach critical mass, and what the future holds.

Fibre Channel: The Predecessor to FCoE

If you are involved in SANs and data centers in general, surely you are familiar with Fibre Channel, the prevalent technology standard in those environments. The introduction of FC solved a variety of problems associated with distance, bandwith, and general performance in the data center, all of which were challenges of copper infrastructures. Additionally, FC is intended to address specifics such as data loss, network congestion, availability, and performance on the network.

Given the volume of adoption of this technology to date, it is clear that FC is employed in many more networks than are alternative technologies such as Infiniband and NAS. This is a key point, because enterprises have invested a significant amount of capital in FC technologies. In order to extend the useful life of FC-based infrastructures, an extension of Fibre Channel to other networking protocols is a must.

FCoE: What is it?

Fibre Channel over Ethernet (FCoE) is an enhancement to FC. By combining the fabrics of FC and Ethernet, data centers will be radically closer to achieving full compatibility of storage, management tools, and drivers across the board. Specifically, FCoE mapping will enable data centers to use Fibre Channel in Ethernet based I/O consolidated environments.

This “converged network” model effectively enables transport of encapsulated FC frames over the Ethernet. To do so, changes to the protocol “stack” were required. In this altered model, the bottom two layers are now combined into Ethernet protocol equivalents. Then, an FCoE “entity” serves as the interface between these Ethernet layers and the Fibre Channel layers, effectively preventing undermining of the existing FC stack and minimizing losses on the conversion.

Various estimates show FCoE reaching more widespread adoption as early as 2010, and others show ranges from 2-3 years in the future (a few even predict it will never reach critical mass). Given the need to evolve the infrastucture rather than outright replace it, I find estimates falling between 2010 and 2012 to be the most sensible. Please comment if your opinion differs. We want to hear your thoughts.

The Future: FCoCEE

We were first exposed to the concept of Fibre Channel over Convergence Enhance Ethernet (FCoCEE) in IBM Redpaper 4493, which reviews all of these Fibre Channel convergence technologies in great detail. Essentially, FCoCEE is to FCoE what FCoE is to FC (say that one three time fast without stuttering).

You see, it is insufficient to simply enable FC and Ethernet to talk because of the lower bandwidth and higher loss rate of Ethernet. For true convergence, the solution must minimize losses, delays, and errors. As such, enhancements to the Ethernet standard itself are in order.

Ethernet Enhancements, 10G, and True Convergence

The first development that is required for this vision to become a reality is the emergence of higher bandwidth Ethernet. Fortunately, enterprises are already actively working to make the shift to 10G as we speak. This “big pipe” availability now makes it possible to successfully execute on storage activities, while still allowing data-heavy activities such as VOIP, Video, and Messaging to take place simultaneously on the same network.

Second, we need a new version of Ethernet itself to address problems with losses and to make 10G more viable as a medium for storage networking data transport. Several other enhancements will be required for addressing bottlenecks, controlling flows, and related activities. All of these issues are currently under discussion by the FC-BB-5 working group of the T11 standard body.

Once we are able to truly bring Ethernet up to the superior loss and bandwidth rates of FC, the vision of FCoCEE will be within reach. We’ve included some resources below should you wish to learn more.

In the meantime, please share your thoughts on the direction this is heading in our Comments section. We want to understand what you think of this concept, how it would help you, and what concerns you have in the future.



Fibre Channel over Ethernet (Wikipedia.com)