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FC-AL (Fibre Channel-Arbitrated Loop) is a subset of Fibre Channel. FC-AL has native support for the IP and SCSI protocols and is characterized by:

· Support for copper, multimode and single-mode fiber cabling;

· The use of GLMs (gigabit-linking modules), which allow an adapter to switch among the three types of cabling;

· Distance between nodes of 30 meters for copper, 1 kilometer for multimode fiber and a whopping 10 kilometers over single-mode fiber--that's a startling 6.21 miles;

· A loop architecture that allows for either a full-duplex (200 MB per second) or half-duplex (single-wire 100 MB per second) setup;

· The use of PBCs (Port Bypass Circuits) to maintain loop integrity and for hot-swappable node creation, allowing individual nodes to hide from the loop; and

· The ability to split the two wires in the loop and send the same data over each, creating real-time redundant applications.

The 100 MB and 200 MB per second speeds are still just theoretical. Any vendor claiming to hit exactly 100 MB or 200 MB per second will likely offer to sell you the Brooklyn Bridge next. Vendors claiming speeds in odd numbers like 85 MB or 90 MB per second are providing more accurate information.

Networking FC-AL is all about SANs (Storage Area Networks). The entire raison d'êStre for building and deploying SANs is to create power data networks featuring tightly concentrated points of storage that can be spread over relatively long distances, along with the inclusion