IBM DS8000 - Manual (Page 177)

Chapter 8. Installation planning 155
You should also keep the following considerations in mind:
Fibre channel SANs can provide the capability to interconnect open systems and storage
in the same network as S/390 and zSeries host systems and storage.
A single Fibre Channel host adapter can have physical access to multiple Fibre Channel
ports on the storage unit.
For some Fibre Channel attachments, you can establish zones to limit the access of host
adapters to storage system adapters. By establishing zones, you reduce the possibility of
interactions between system adapters in switched configurations.
You can configure switch ports that are attached to the storage unit in more than one zone.
This enables multiple system adapters to share access to the storage unit Fibre Channel
ports. Shared access to a storage unit Fibre Channel port might come from host platforms
that support a combination of bus adapter types and operating systems.