HP 2100 ER manual Laser Power Control Systems, Device Addressing

Fibre Channel Overview

Problems with Fibre Channel

Laser Power Control Systems

There are two types of systems approved for use: OFC and non-OFC. These two types of control systems can exist on the same network, but are not optically compatible and cannot be hooked up to the same optical cable.

Device Addressing

The two modes of addressing used in Fibre Channel, included on page A-7, are hard and soft addressing. In small, controlled environments, hard addressing works well. Also, some operating systems and host bus adapters do not support soft addressing. Large Fabric networks, connecting many devices, require the flexibility of soft addressing; hard addressing is not supported in a Fabric environment.

HBA drivers cannot dynamically track device addresses that can change after the system is turned on. Physical addresses change while the operating system uses the same logical name for the device. Applications that always use the same physical device may use the World-Wide Name (WWN). For example, backup programs must locate the library and all of its drives regardless of the bus address. Fibre Channel resolves these issues.

Proper system planning and research prior to installing a Fibre Channel
system will help avoid these problems. Configured properly, Fibre	Fibre Channel Overview
Channel is as reliable and easy to use as current SCSI systems.

Appendix A A-11