An effective I/O protocol for taking advantage of system area network functionality, whether or not a particular application is written to do so, is provided. Transparently to the application, the I/O protocol routes application I/O commands via legacy transmission protocols or via remote direct memory access protocols as appropriate. When communicating via remote direct memory access protocols, the I/O protocol can take advantage of multiple data exchange commands implemented by these protocols to perform the required data exchange. Once an I/O operation has completed, the I/O protocol passes a completion notification to the application using a polling or interrupt construct.