How does HP iLO and Dell iDRAC be configured in vCAC?

Hello folks,

While creating new Endpoints to configure physical severs, we have a few options: HP iLO, Dell iDRAC and Cisco UCS. When we create a new reservation with physical servers, does vCAC communicate with the underlying server automation software (such as HP SA or BSA or others) or directly talk to physical servers via the above end points ?

vCAC provides integration (not OOTB) with HP SA and I believe with BMC Blade logic as well so trying to understand how would vCAC communicate with physical servers?

It would be great to know the underlying process for physical servers configuration in vCAC.

thanks