Issue:
Why does DCE download a device definition file (DDF) from an APC device?

Product Line
StruxureWare Data Center Expert (DCE) StruxureWare Central (SWC)
InfraStruXure Central (ISXC)

Environment:
StruxureWare Data Center Expert (All Versions)
Network Management Card (NMC)

Cause:
There are already DDF files that reside on StruxureWare when an APC device is discovered, it tries to download a DDF from the device.

Resolution:

There are often multiple DDFs in use at one time. The 2 main DDFs being used by APC devices are the "scanner" DDF and the "alerts" DDF. Some devices often use more than 1 scanner DDF as well as a UPS may have environmental functionality etc.

The scanner DDF resides on the DCE server. It is used to tell DCE what data points to poll. These provide the information that you see in reports and if you right click a device and choose to view device sensors. This DDF is updated when you update your DCE version or when you manually choose to update DDFs.

The alerts DDF is stored on the APC device and transferred to DCE when the device is discovered or if the device's firmware is updated. These DDFs tell DCE what they should alert for on that specific device. If you go to the alarm configurations perspective in DCE, you'll see that APC devices have numerous pre-configured alerts in the device alarm configurations tab. These alarms come from the DDF that is transferred from the device itself. DCE then keeps track of which alert DDF to use for each device/firmware in the off chance that you update firmware (and subsequently the alert DDF) for some devices but not others.

There are a few third party devices that have pre-configured alarms as well and they are built into the scanner DDFs. With APC devices however, newer firmware may have new alarm options and by putting the alarm DDF on that device/firmware, the firmware developers for device itself dictate what device alarms are written in to the DDF and subsequently reported by DCE without the need to update the scaner DDF.