Using peripheral component interconnect express vendor-defined message (PCIe-VDM) and inter-integrated circuit (I2C) transport for network communications

Systems and methods for using Peripheral Component Interconnect Express Vendor-Defined Message (PCIe-VDM) and Inter-Integrated Circuit (I2C) transport for network communications are described. In some embodiments, an IHS may include: a host processor; a Basic Input/Output System (BIOS) coupled to the host processor; a Baseboard Management Controller (BMC) coupled to the host processor; and a memory coupled to the BMC, the memory having program instructions stored thereon that, upon execution, cause the BMC to: receive a message over a network while the host processor is powered off, wherein the message originates from a remote IHS and targets the BMC; and in response to a pass-through data transfer rate available to the BMC not meeting a threshold value: power on the host processor; request that the BIOS boot up; and perform a communication with the remote IHS via a PCIe bus using a PCIe-VDM supported by the host processor.