ESCON and FICON® system hardware, CPCs, and ESCON and FICON Directors,
can significantly affect the volume of logical path requests to a
control unit as follows:
- Control units can attach to one or more ports on a director or
to additional ports on other directors. Each director port can dynamically
connect to many other ports to which attached channels are requesting
logical paths.
- Each logical partition with channels attaching to the same control
unit competes for the logical paths of the same control unit.
- In a configuration where control units are shared by different
CPCs, I/O configuration definitions for individual control units are
not coordinated automatically among the IOCDSs of the different CPCs.
Each CPC competes for the logical paths of a control unit.
- Shared channels require the establishment of a logical path for
each active logical partition sharing the channel. This requirement
can significantly increase the number of logical paths that a single
channel requests.