1 HV Installation and Operations Guide

232 SCC Addressing Option Appendix C

SCC Addressing Option

When a bridge is configured to use SCC addressing, the unit is capable of

responding as a controller device to the FCP initiator or routing the FCP

request to a specified bus:target:LUN. When a request using the peripheral

device addressing method is received (an FCP command with the LUN field

with bits 7 and 6 of byte 9 are set to 0), the unit routes the request to the

internal processor, which acts on the command directly. When a request using

the logical unit addressing method is received (bits 7 and 6 set to 10b), the

request is routed to the bus:target:LUN as specified in the defined field.

Host systems using SCC addressing will typically do initial device discovery

using the peripheral device addressing method. On issuing an INQUIRY

command to the bridge, the host will receive the bridge inquiry data,

indicating the device type as a controller device (inquiry data indicated device

type is 0xC). The host will then know that subsequent commands to the bridge

attached devices will use the logical unit addressing method.

The host can perform discovery by either walking through the bus:target:LUN

values as would a standard SCSI driver, or by issuing a report LUNS

command. This command is sent to the bridge (using the peripheral device

addressing method), and the bridge returns a table indicating attached

devices. The host can then perform actions on these bridge attached devices

directly without having to perform discovery by issuing commands through all

possible combinations.