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For the extra money, 8Gb/sec components will bring some new capabilities. "These involve how data corruption is handled and how you authenticate the host to the FC fabric," says McIntyre. For example, there'll be more Cyclic Redundancy Checks (usually a mathematical checksum), which detect data alteration during transmission or when stored by comparing the data stream going in and coming out.
One upshot of the transition to 8Gb/sec FC may be improved energy conservation. "You may be able to turn off lanes on the PCI bus and power off lanes in the HBA and ports," says QLogic's Lustig. These green capabilities, however, will come from new firmware and software, not from the 8Gb/sec HBA alone.
| low-latency and QoS-enabled Ethernet. FC becomes just another network protocol running at 10Gb/sec alongside IP on the 10GbE network.
FCoE also allows convergence at the cabling level through a single Ethernet cable handling both FC and IP. FCoE will appeal to enterprises with FC SANs but with no plans to migrate to iSCSI and Ethernet. "It lets organizations with FC and FICON preserve their FC skills and tools," explains StorageIO Group's Schulz. They can converge their network to a fast 10GbE backbone and reap savings by running and maintaining only one set of cabling for all traffic. (For more, see "FCoE: Coming to a data center near you".)
Because FCoE doesn't use TCP/IP, it isn't routable. In addition, at this point FCoE is considered local technology only. "FC shops that want to follow strategies requiring long distance, such as remote mirroring, should look to FCIP [Fibre Channel over IP] or other protocols," says Schulz.
To use FCoE, organizations will have to deploy a Converged Network Adapter (CNA) that will look to the server as both an FC HBA and an Ethernet NIC. A number of vendors have declared support for FCoE, including switch makers like Brocade and Cisco and component makers like Emulex and QLogic. Despite industry support, "this technology is still in its infancy," adds Schulz. "It will be 2010 before FCoE is ready for use by anyone except early adopters." (See "Fibre Channel over Ethernet roadmap," PDF below.)
This was first published in July 2008