An American National Standards Institute (ANSI) specification (X.3230, 1994) for a high-speed link between computers and peripherals, primarily high speed external storage devices. Developed to replace High Performance Parallel Interface (HIPPI) and as a high-speed alternative to the distance-limited Small Computer System Interface (SCSI), Fibre Channel is intended to support applications such as data backup and mirroring, and is the predominant data link technology employed in storage area networks (SANs). Fibre Channel is connected at Layer 1, the Physical Layer, by fibre, a term the Fibre Channel industry coined to refer to a network comprising a close-knit fabric of access including both optical fiber and copper twisted pair for large data transfers with low overhead, low-latency switching, and minimal interruptions to the flow of data. The preferred physical medium is optical fiber, which can be multimode fiber (MMF) of either 62.5