ATTO Technology 2200R/D, 3200R What to Expect When Setting Device IDs, SCSI-3 Report LUNs Command

ATTO Technology, Inc. ATTO FibreBridge Installation & Operation Manual

and the Report LUNs command as described in the next section. FibreBridge hierarchical addressing is limited to the first-level LUN support. More information is available in the reference documentation.

SCSI-3 REPORT LUNs Command

The SCSI-3 Report LUNs command returns a sorted list of LUNs available (at the time of execution of the Report LUNs command) on the FibreBridge. LUNs in the returned LUN-list are formatted according to the Peripheral Device Addressing Method. Although Report LUNs may be issued to the FibreBridge or to any SCSI device attached to the FibreBridge, it is always executed by the FibreBridge and is not forwarded to any attached SCSI devices. Additional information is available in the reference documentation.

What to Expect When Setting Device IDs

Most users will be able to use the FibreBridge Default Addressing Method to achieve full functionality.

Setting the ID of the FibreBridge

The ID is determined from either the Soft or Hard Fibre Channel ID of the FibreBridge (AL_PA). The FibreBridge is set to use Soft IDs by default. The bridge can be set to use a Hard ID by using FibreBridge Services to set the appropriate bit in the NVRAM. The LUN of the FibreBridge can also be set using FibreBridge Services (BridgeTools is recommended). The default value is 14.

If you want the FibreBridge to be detected by the operating system, its Soft Fibre LUN value must be set within the range of the operating system. The bridge does not need to be detected for normal operation. The bridge DOES need to be detected if you want to use the in-band connection method for BridgeTools. The FibreBridge will never be detected in UNIX environments because the operating system does not contain a native device driver for bridge devices.

Addressing Connected SCSI Devices

Below is the default addressing mode bit definitions. Bits 0 through 7 are used to fully define a SCSI device with a Target ID and a LUN connected to one of the two FibreBridge busses.

Bit Number

15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
0	0			N/A					LUN			Target			Bus

An operating system will identify this SCSI device under the AL-PA of the FibreBridge, based upon its hard or soft ID, and the LUN based upon the bit definition above.

The four bit Target Field gets filled in from the SCSI ID (0 through 15) that you select for your connected SCSI device. The three bit LUN Field gets filled in from the SCSI LUN (0 through 7) selected for your connected SCSI device. Since the FibreBridge contains two independent busses, but is only being detected as a single device from the host's point of view, the FibreBridge must manage the addressing between bus 1 and bus 2. The bus bit(s) in the LUN byte is used to distinguish between SCSI bus 1 and

2.If you set the bus bit(s) to 0, SCSI Bus 1 of the FibreBridge will be selected. A 1 will select Bus 2. The default addressing mode of the FibreBridge has the Bus Identifier bit in position 0. This translates to Bus

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