Efficient at-most-once messages based on synchronized clocks

A novel message-passing protocol that guarantees at-most-once message delivery without requiring communication to establish connections, is described. The authors discuss how to use these messages to implement higher level primitives such as at-most-once remote procedure calls (RPC) and describe an implementation of at-most-once RPCs using their method. Performance measurements indicate that at-most-once RPCs can be provided at the same cost as less desirable RPCs that do not guarantee at-most-once execution. The method is based on the assumption that clocks throughout the system are loosely synchronized. Modern protocols provide good bounds on clock skew with high probability; the present method depends on the bound for performance but not for correctness