A method mechanism is provided for communication between host systems using a transaction protocol and shared memories. Shared memories are initialized based on a discovery process in a communication fabric such that at least one endpoint has address ranges in shared memories of at least two host systems. A transaction oriented protocol may be established for using the shared memories of the host systems to communicate between root complexes and endpoints of the same or different host systems. The transaction oriented protocol specifies a series of transactions to be performed by the various elements, e.g., root complex or endpoint, to push or pull data. Various combinations of push and pull transactions may be utilized.