Compaq External RAID Controller & Subsystem Infortrend Operation Manual page 159

Enter a unique ID for any RAID controller no matter it is configured
in a single or dual-controller configuration.
necessary for the following:
1.
2.
3.
In redundant mode, configuration data is synchronized between
controllers. Host ports on both controllers appear with the same
node name but each with a different port name (WWPN).
When a controller fails and a replacement is combined as the
Secondary controller, the node name will be passed down to the
Secondary controller.
differences so that controller failback is totally transparent.
The unique identifier setting can be accessed from "View and Edit
Configuration Parameters"
Unique ID."
Terminal Operation
A controller-specific identifier that helps controllers to identify
its counterpart in a dual-active configuration.
The unique ID is generated into a Fibre channel WWN node
name for controllers or RAID systems using Fibre channel host
ports. The node name is used to prevent host computers from
mis-addressing the storage system during the controller
failover/failback processes.
MAC addresses for the controller's Ethernet port that should be
taken over by a surviving controller in the event of controller
failure.
The host will not acknowledge any
"Controller Parameters"
The unique ID is
"Controller
7-40