Channel Link – The address of the ESCON director port that connects to the mainframe this device is to communicate with. The value range is from 01-FE hexadecimal. In Figure 4-2 the mainframe uses a channel link address '02' to communicate with Server 1. Server 1 uses a channel link address '01' to communicate with the mainframe. In this example, the Channel Link in the adapter configuration is set to '01'.
Figure 4-2. Channel Link Address
If no director is used, the channel sub-system will assign an arbitrary LINK address (usually 01) for the server to communicate with the mainframe. To ensure the mainframe always selects '01' you should assign '02' to the channel adapter’s device in the IOCDS. Code the LINK parameter in the CNTLUNIT macro in the I/O Configuration Data Set (IOCDS) to '02' as shown in the following example:
CNTLUNIT ...,LINK=(02),....
Then set the channel link '01' in the adapter's configuration.
Logical Partition Address (LPARS) – This is a hexadecimal number ranging from 0-F identifying the logical partition (LPAR) ID of the Logical partition this connection is to communicate with. This parameter is only required if EMIF is enabled. For BASIC mode or LPAR mode non-EMIF, set this field to zero (0). If EMIF is enabled this number must match the LPAR ID assigned in the Logical Partition Definition (LPDEF) frame which appears in LPAR mode after a power on / reset. In LPAR mode the CPU ID contains this number as it's fourth character. If running the VM operating system, the "QUERY CPUID" command will display the CPU ID. The fourth character of the CPU ID is the LPAR ID.
The remainder of this chapter discusses how to modify the configuration parameters for your PCI ESCON Adapter.