Peer-to-peer communication between reconfigurable dataflow units

A computing system is disclosed, comprising a plurality of interconnected reconfigurable dataflow units (RDUs). Each RDU includes configurable units, internal networks, and external interfaces. The first configurable unit of the first RDU sends a request to access an external memory attached to the second RDU over its first internal network. The second configurable unit of the first RDU obtains a memory address for the request, determines an identifier for the second RDU, and sends the request, identifier, and memory address to the third configurable unit of the first RDU over its second internal network. The third configurable unit of the first RDU generates a routable address on the external network, synthesizes a payload, and sends it through an external network interface. The third configurable unit of the second RDU receives the payload, and the fourth configurable unit of the second RDU uses the address to access the external memory.