How Fabric Assist Mode Works; Zone Configuration Limits - HP StorageWorks 2/16 - SAN Switch User Manual

Using QuickLoop Fabric Assist Mode

How Fabric Assist Mode Works

There are significant implications about the implementation of Fabric Assist
zones, especially considerations of LIPs, and the interaction with QuickLoop
zones.
The standard QuickLoop implementation imposes the following limitations:
Fabric Assist mode zoning supports operations between private initiators and
public targets without imposing these limitations. The initiator and target can exist
anywhere in the fabric. A public target remains public, with full fabric
functionality.
In order to support this, prior to loop initialization, phantom translation tables are
set up in the switch that is connected to a private initiator. These tables represent
phantom targets on the private initiator's loop. The switch creates a phantom table
entry for each target zoned with the private host. Upon completion of the
initialization process, the private host will "see" a valid AL_PA for each target that
it has been zoned with. As the initiator communicates with each phantom, the
phantom translation process transforms the frame into a public frame, and
transmits it to the fabric.

Zone Configuration Limits

The number of public targets that may be zoned with a single private host depends
on the number of phantom nodes that may be created on the private host's loop.
The number of phantoms that may be created are limited only by the number of
entries within the phantom tables of the switch, and the total number of available
AL_PAs.
The switch's phantom translation table may contain a maximum of 125 unique
phantom translations. The existing translative process utilizes the same phantom
translation tables, thus reducing the maximum number of Fabric Assist targets that
may exist if this feature is used.
Each private looplet has its own allocation of 126 AL_PAs. Therefore each private
host may be zoned with all 125 public targets.
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A QuickLoop is confined to at most two switches in a fabric.
There can only be 29 private hosts supported in a QuickLoop.
Even though a target device can be public, it is forced to perform as a private
loop device in a QuickLoop. This prohibits the public target from using fabric
functions such as Extended Fabrics.
Quickloop Fabric Assist User Guide