Alveo U45N accelerator card supports both in-band and out-of-band communication with the host. In-band communication is provided by PCIe bus with sixteen lanes allocated to the XCU26. In addition, in-band communication with the management subsystem, particularly reading any sensor values, is done via the satellite microcontroller on board the U45N card.
The card satellite controller (SC) provides independent supervisory and card management functions including power and temperature monitoring. The host server board management controller (BMC) can interact with the satellite controller to monitor and control the card through out-of-band communication. The card supports the PLDM protocol over MCTP over SMBUS, complying with the DMTF standards. Refer to the Alveo Card Out-of-Band Management Specification for Server BMC (XD038).