Figure 5 Mainframe logical paths (example 2)
.
The FICON /zHPF CHAs provide logical path bindings that map user-defined FICON/zHPF logical
paths. Specifically:
Each CU port can access 255 CU images (all CU images of logical storage system).
To the CU port, each logical host path (LPn) connected to the CU port is defined as a channel
image number and a channel port address. The LPn identifies the logical host path by the channel
image number and channel port address (excluding CU image number).
In the following figure, Host Path(1) and Host Path(2) have the same channel image number and CU
image number. However, they correspond to different paths because the channel address (and LPn)
is different.
Figure 6 FICON/zHPF channel adapter support for logical paths (example 1)
.
The following figure shows another example of logical paths. Instead of being controlled by physical
ports, LPns on the storage system are controlled by CU images. Separating LPns from hardware
provides flexibility that allows CU ports to share logical path resources as needed.
Specifically:
Maximum number of LPn/CU images per storage system is 2048.
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