Storage area network (SAN) protocols: iSCSI and Fibre Channel
In addition to their components and architecture, storage area networks (SANs) are also defined by their interconnection scheme, which usually falls into either Fibre
Channel or iSCSI
. FC technology is clearly the most popular approach for enterprise data center storage area networks. FC supports communication between servers and storage devices at 2 Gbps, though 4 Gbps implementations are now common, and 10 Gbps implementations are expected in the future. FC traditionally uses optical fiber cables to interconnect devices and is still employed over long distances. Today, short distance FC implementations can be achieved with coaxial and twisted-pair copper cables. FC can operate directly between two devices (point-to-point), or network multiple storage devices through a switch or arbitrated loop. FC technology is compatible with SCSI
iSCSI is an emerging Internet Engineering Task Force standard that allows SCSI commands to support data storage and retrieval over Ethernet networks that include LANs, WANs and the Internet. By leveraging the broad acceptance of IP networks, iSCSI technology is expected to strengthen the SAN market and has already found acceptance in small and midsized organizations for basic SAN deployments. Since Ethernet networks generally work up to 1 Gbps, iSCSI isn't as fast as FC, which starts at 2 Gbps. However, iSCSI is less expensive than FC, and Ethernet is well-understood by any IT professional. In addition, 10 Gbps Ethernet is on the horizon and could also threaten FC's established position as the SAN networking technology of choice.
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This tip originally appeared on SearchStorage.com.
This was first published in November 2006
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