In this paper we present an eecient design for message passing over a reeective memory network. First, we consider the attributes of reeec-tive memory communication networks and the requirements to eeciently build message-passing functional-ity on these networks. We then introduce the Bill-Board Protocol, a lock-free protocol which provides low-latency send, receive, and multicast functionality to higher-level applications over reeective memory networks. The communication protocol and an implementation on SCRAMNet is described in detail. Lastly, the performance of this protocol is demonstrated.