A method of communicating data over a Peripheral Component Interconnect Express (PCIe) Non-Transparent Bridge (NTB) comprising transmitting a first posted write message to a remote processor via the NTB, wherein the first posted write message indicates an intent to transfer data to the remote processor, and receiving a second posted write message in response to the first posted write message, wherein the second posted write message indicates a destination address list for the data. Also disclosed is a method of communicating data over a PCIe NTB comprising transmitting a first posted write message to a remote processor via the NTB, wherein the first posted write message comprises a request to read data, and receiving a data transfer message comprising at least some of the data requested by the first posted write message.