Quickloop Basics; Address Translation - HP StorageWorks 2/16 - SAN Switch User Manual

Introducing QuickLoop

QuickLoop Basics

QuickLoop is a unique Fibre Channel topology that combines arbitrated loop and
fabric topologies. An arbitrated loop supports communication between devices
that are not fabric-aware. Such devices are called private devices, and arbitrated
loops are sometimes called private loops.
QuickLoop allows a SAN Switch 8-EL/16-EL to emulate a hub environment,
while offering the additional benefit of connectivity to a fabric.
A QuickLoop consists of multiple private arbitrated looplets (a set of devices
connected to a single port) that are connected by a fabric. All devices in a
QuickLoop share a single AL_PA bit-map and behave as if they are in one loop.
This allows private devices to communicate with other devices over the fabric,
provided they are in the same QuickLoop.
A particular QuickLoop can be configured to consist of selected devices or
looplets connected to the ports of one switch, or to a cascaded switch pair.
QuickLoop provides a possible migration path starting with deploying a single
private loop and later deploying a fabric-based SAN. In this scenario,
QuickLoop-enabled switches can be used to replace hubs when the SAN is first
deployed and has only private devices attached. Then, as the SAN grows, fabric
switches can be added without any detrimental effect to the QuickLoop-enabled
switches.

Address Translation

Address translation is transparent and requires no actions on the part of the user. It
is achieved through hardware translative mode (also known as phantom mode), in
which a device not physically located in a looplet is made addressable by a unique
AL_PA in that looplet.
Two hardware translative modes are available to a QuickLoop-enabled switch:
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Standard translative mode—Allows public hosts to communicate with
private target devices across the fabric. Standard translative mode is available
as an integral part of Fabric OS, and does not require QuickLoop.
QuickLoop mode—Allows private hosts to communicate with private target
devices across the fabric when configured in the same QuickLoop. Also
allows a private host to communicate with a public target in the same
QuickLoop.
Quickloop Fabric Assist User Guide