HP E1200-320 manual Addressing, structures, and operations, SCC addressing structure

D Addressing, structures, and operations

Fibre Channel and SCSI systems employ different methods of addressing devices. The inclusion of a interface card requires that a method of translating device IDs be implemented so that each SCSI device is mapped to the appropriate Fibre Channel LUN. The SCSI buses establish bus connections between devices. Targets on a SCSI bus may internally address logical units. The addressing of a specific SCSI device is represented by the BUS:TARGET:LUN triplet.

When a Fibre Channel initiator initializes on a loop, the host must first determine what devices exist on the loop. Device discovery is performed, and an FCP target device list is built. Each device is queried for FCP logical units. The logical units are the actual devices that the operating system will address. When an initiator addresses a logical unit, the LUN field used is consistent in form with the SCC defined fields. All current Fibre Channel host bus adapter drivers are consistent with these methods. The addressing used is the SCC Logical Unit Addressing and Peripheral Device Addressing methods, shown in Table 17 and Table 18. First level addressing is supported, so only the first 2 bytes of the 8-byte FCP LUN are used.

Table 17 SCC addressing structure

Bit	7	6	5		4		3	2	1	0
Byte
N	Address Method					Address Method Specific
N+1				Address Method Specific

Table 18 Address method definitions

Codes	Description
00	Peripheral Device Addressing Method
01	Volume Set Addressing Method
10	Logical Unit Addressing Method
11	Reserved

Table 19 SCC logical unit addressing

Bit	7		6	5	4	3		2	1	0
Byte
N	1		0				Target
N+1		Bus					LUN

Table 20 Peripheral device addressing

Bit	7	6	5	4		3		2	1	0
Byte
N	0	0					Bus
N+1					Target/LUN

e1200-320 4Gb Fibre Channel Interface Card user and service guide 113