HP StorageWorks Fabric OS 5.3.x administrator guide (5697-0244, November 2009)

152 Managing administrative domains
always exist and cannot be deleted or renamed. They are reserved for use in creation and management of
Admin Domains.
AD0
AD0 is a system-defined Admin Domain that, in addition to containing members you explicitly added
(similar to user-defined Admin Domains), contains all online devices, switch ports, and switches that have
not been assigned to any user-defined Admin Domain.
Unlike user-defined Admin Domains, AD0 has an implicit and an explicit membership list. User-defined
Admin Domains have only explicit members.
• The “implicit membership list” contains all devices, switch ports, and switches that have not been
assigned to any other Admin Domain.
Initially, the AD0 implicit membership list contains all devices, switch ports, and switches in the fabric.
This implicit membership list includes all AD-unaware switches and the devices attached to them. When
you explicitly create AD1 through AD254, the devices, switch ports, and switches used to create these
user-defined Admin Domains disappear from the AD0 implicit membership list.
• The “explicit membership list” contains all devices, switch ports, and switches that you explicitly add to
AD0 and can be used to force device and switch sharing between AD0 and other Admin Domains.
Explicit members can be added to AD0 using the ad --add command.
AD0 can be managed like any user-defined Admin Domain. The only difference between AD0 and
user-defined Admin Domains is the implicit membership list.
The implicit members of AD0 change dynamically as the membership of other Admin Domains changes.
The explicit members of AD0 are not deleted unless you explicitly remove them.
For example, if you explicitly add DeviceA to AD0 and it is not a member of any other Admin Domain,
then DeviceA is both an implicit and an explicit member of AD0. If you add DeviceA to AD2, then DeviceA
is deleted from the AD0 implicit membership list, but is
not deleted from the AD0 explicit membership list. If
you then remove DeviceA from AD2, DeviceA is added back to the AD0 implicit membership list (assuming
DeviceA is not in any other Admin Domain).
When a new device is added to the fabric, it automatically becomes an implicit member of AD0 until it is
explicitly added to an Admin Domain.
AD0 is useful when you create Admin Domains because you can see which devices, switch ports, and
switches have not yet been assigned to any Admin Domains.
AD0 owns the root zone database (legacy zone database). During zone merge or zone update, only the
root zone database is exchanged with AD-unaware switches.
AD255
AD255 is used for Admin Domain management. You can use AD255 to get an unfiltered view of the fabric
and to view the hierarchical zone databases of AD0 through AD254. All Admin Domain management is
done in the AD255 context.
AD255 does not have a zone database associated with it; you cannot use AD255 to perform any zoning
management tasks (non-read operations such as creating or modifying zones).
Figure 5 shows the same fabric from Figure 3, but with AD0 and AD255 shown. AD0 contains the two
devices that are not in any of the user-defined Admin Domains (AD1 and AD2). AD255 encompasses the
entire physical fabric.