Asynchronous Leasing

Leasing is a very effective way to improve the performance of distributed algorithms without hampering their fault-tolerance. The notion of lease has traditionally been defined using a global notion of real time and was hence strongly tied to synchronous system models. This paper introduces a notion of lease object devised for an asynchronous system model. We give precise properties of our lease abstraction, and show how it can be implemented in an asynchronous system model with a logical notion of time. We then illustrate its use by showing how it significantly improves the performance of a consensus-based atomic broadcast algorithm and we point out other possible lease applications.