Table of Contents
Advertisement
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
ATTO Technology, Inc.
- 42 -
Advertisement
Table of Contents
