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FCoE Aims To Cut the Cords to Storage Networking

Organizations running standalone Fibre Channel-based Storage Area Networks may be able to reduce the amount of cabling snaking through their datacenters, thanks to an emerging converged network protocol called Fibre Channel over Ethernet (FCoE).

Last June, the International Committee for Information Technology Standards' T11 Technical Committee finalized the FCoE standard (PDF). Now products are starting to hit the market that will allow agencies to take advantage of this emerging storage technology.

At the Intel Developer Forum in San Francisco last week, Mellanox Technologies released the industry's first 40 gigabit Ethernet adapter, the ConnectX-2 EN 40G, which supports FCoE. That single Ethernet cards will soon be able to manage 40 gibabits per second -- and not lose any packets thanks to recent Ethernet refinements -- will make it easier for organizations to pave the way for folding their Fiber Channel-driven storage networks into general-use Ethernet networks.

Elsewhere, Brocade has released a new model of its DCX Backbone switches to specially handle Fibre Channel traffic between two datacenters using Ethernet, the FCoE10-24 Blade. This blade will be available in EMC, Hitachi Data Systems, HP and NetApp storage offerings.

FCoE allows Fibre Channel traffic to be run over an Ethernet network. Using FCoE can reduce the amount of infrastructure in a datacenter because it eliminates the need to maintain a Fibre Channel network dedicated for storage. Instead, the Storage Area Network traffic could be run over the existing Ethernet network, noted Skip Jones, chairman of the Fibre Channel Industry Association.

Technically speaking, with FCoE, the Fibre Channel-encoded data is bundled in Ethernet packets at its source and, after traversing an Ethernet network, is unbundled at its destination. "The Fibre Channel protocol at the link level is exactly the same. All [FCoE] does is allow us to run over a different wire," said Steve Wilson, chairman of the T11 committee. "All the management applications and all the actual operational functionality [are] the same."

Although Fibre Channel networks have traditionally offered a higher line rate than Ethernet, Ethernet's recent jumps to 10 and 40 gigabit throughputs can even the playing field between the two technologies. So the performance difference between natural Fibre Channel and FCoE "should be completely negligible," promised Jones.

To set up an FCoE for an existing SAN, you would need two new types of components: FCoE converged network adapters for the storage arrays and the servers, as well as datacenter bridge exchange (DCBX) switches to connect the end-points. Architecturally, a storage array could be FCoE-enabled, meaning communication with this array would happen directly over Ethernet, with FCoE packets. Organizations running existing Fibre Channel SANs could connect the arrays with a DCBX switch via Fibre Channel, and then route all outward connections via Ethernet, Jones noted.

Although the standard has been stabilized for some time, Wilson said, this final official ratification will bring the assurance of product interoperability among the many vendors selling FCoE gear. It will also allow companies that weren't part of the T11 development committee to purchase the standard specification and implement FCoE support into their own storage products. The FCoE standard has also adapted the worldwide Media Access control (MAC) addressing system for network components, so that all FCoE hardware components will have a seared-in-silicon universal MAC address.

The University of New Hampshire does periodic plug-fests, where different vendors can come together to set up an ad-hoc networks to demonstrate how well Fibre Channel equipment from different vendors could work together. The next one will be held Nov. 16-20.

About the Author

Joab Jackson is the chief technology editor of Government Computing News (GCN.com).

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