Addressing, Structures And Operation - ADIC FCR 200 Operator's Manual

Adic router operator guide

Table of Contents

Addressing, Structures and Operation

Table D-1

Bits

Bytes

Address Method

n+1

Table D-2

Bits

Bytes

n+1

Fibre Channel and SCSI systems employ different methods of

addressing devices. The inclusion of a bridge or router

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 an arbitrated

loop, the first order of business is to 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 D-1

and Table D-2. First level addressing is supported, so only the

first 2 bytes of the 8 byte FCP LUN are used.

SCC Addressing Structure

Address method Specific

Peripheral Device Addressing LUN Structure

Target/LUN

Address Method Specific

Bus