About the Fibre Channel-Arbitrated Loop (FC-AL) and Port
Fibre Channel (FC) is a standard that defines a high-performance serial interconnection designed for bidirectional, point-to-point communication among servers, workstations, and storage systems.
Fibre Channel-Arbitrated Loop (FC-AL), an important enhancement to the FC standard, was developed specifically to meet the needs of storage system interconnections. FC-AL employs a simple loop topology that can support both simple configurations and complex arrangements of multiple loops attaching many devices (hubs, switches, servers, and storage systems).
FC-AL devices employ a serial interface, which transfers multiple standard protocols such as Small Computer System Interface (SCSI) and Asynchronous Transfer Mode (ATM). By supporting these standard protocols, FC-AL preserves your investment in existing legacy systems, firmware, applications, and software.
The Sun Fire 280R system supports a single FC-AL loop. The internal FC-AL disk controller application specific integrated circuit (ASIC)—the QLogic 2200A—is the interface between the 64-bit 66-MHz PCI bus and the rest of the FC-AL loop, and serves as the loop controller. The FC-AL disk controller ASIC also supports fabric switches, and thus both additional public and private loops are configurable using the external port. PCI adapter cards can also be on the same loop as the QLogic 2200A controller ASIC.
The FC-AL host controller ASIC provides a 64-bit, 66-MHz Extended PCI (EPCI ) interface and the disk drives are connected to the loop through a hub. Access to the loop for the disk drives is through the FC-AL backplane. Access to the loop via the external port for mass storage is through the copper High-Speed Serial Data Connector (HSSDC) on the back panel. No Gigabit Interface Converter (GBIC) adapter is supported.
On the FC-AL controller, internal signal detect circuitry on the hub automatically detects any signal coming from the external connector, which then enables the external port. Lack of an external signal causes the external connection to be disconnected from the loop. The individual ports can also be bypassed manually via a software probe and programming a General Programming I/O (GPIO) register in the FC-AL controller.
The host controller implements the FC protocol through a microcoded engine. The memory for the firmware is external and is implemented with synchronous
128-Kbyte static random access memory (SRAM). For the connector diagrams, back panel icon, and pin assignments, see “Reference for the Fibre Channel-Arbitrated Loop (FC-AL) Port Connector” on page 214.
