This standard describes a communication interface between a channel and I/O control units that utilize the Single-Byte Command Code Sets (SBCCS) as implemented in a wide range of data processing systems. It employs information formats and signaling protocols that provide a uniform means for communicating with various types of I/O control units, facilitating a high-bandwidth, high-performance, and
long-distance information exchange environment. The signaling protocols and information exchanges are defined at a layer (FC-4) to compatibly utilize the link services and other functions provided by the INCITS Fibre Channel Framing and Signalling (FC-FS-4) and the INCITS Fibre Channel Link Services (FC-LS-3) specifications. This FC-4 Upper Level Protocol is referred to as the Fibre Channel - Single-Byte Command Code Sets Mapping Protocol - 5 (FC-SB-5). It modifies the FC-SB-4 standard, which defined the transport mode of operation, to specify enhancements to the transport-mode protocols to increase the efficiency and expand the capabilities of transport-mode operations. Additionally, link-control protocols are defined that utilize new control-unit discovery protocols that enhance the I/O configuration and link initialization process.
