A network interface device is connected to a host computer by having a memory controller, and a scatter-gather offload engine linked to the memory controller. The network interface device prepares a descriptor including a plurality of specified memory locations in the host computer, incorporates the descriptor in exactly one upload packet, transmits the upload packet to the scatter-gather offload engine via the uplink, invokes the scatter-gather offload engine to perform memory access operations cooperatively with the memory controller at the specified memory locations of the descriptor, and accepts results of the memory access operations.