McDATA 3000 manual Dynamic Target LUN Discovery and LUN Mapping, Overview, Target Discovery

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Dynamic Target LUN Discovery and LUN Mapping

		The server UltraNet Edge 3000 may also be statically configured for a
		specific UltraNet Edge 3000 target LUN to be bound to a designated
		remote target WWN.
	Dynamic Target LUN Discovery and LUN Mapping
		The following sections provide an overview of target and LUN
		discovery and both dynamic and static mapping.
	Overview	When an Edge Fibre Channel interface is configured for FCP, it may
		be configured as an Edge target, an Edge initiator or both. The Edge
		initiator actively connects to device targets. The Edge target passively
		connects to host initiators.
		The Edge target and Edge initiator maintain arrays of I_T_L
		connections based upon SCSI IDs. In implementing FCP, the port ID
		or alpa is used in place of the SCSI ID to maintain the SCSI ULP
		functionality.
		To host initiators, the Edge target appears as a single target with
		multiple LUNs. When LUN 0 is configured in Emulate mode, it will
		appear as a device type controller. When LUN 0 is configured in
		Passthru mode, it will represent an actual remote device. In either
		case, the Report LUNs command will be handled locally in the Edge
		attached to the host and the response will indicate all available host
		LUNs.
		The Report LUNs command is handled by the Edge target and
		reflects the number of configured LUNs (SCSItoSCSIdataPath). The
		response to a Report LUNs command merely indicates the number of
		LUNs available. This information is forwarded to the host regardless
		of the number or the state of remote targets.
		The number of LUNs configured will be 8 (not counting LUN 0) by
		default with a max of 32.
		Current FCP Edge target to FCP Edge initiator is strictly
		point-to-point.
	Target Discovery	The Edge initiator will dynamically discover available targets and
		actively login/logout of those targets as conditions warrant. The
		WWN and associated port IDs of each currently logged in target, is
		forwarded to the associated Edge target on a regular timed interval.
	McDATA UltraNet Edge 3000 User Guide
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