|This paper presents Aegean, a new approach that allows fault-tolerant replication to be implemented beyond the confines of the client-server model. In today?s computing, where services are rarely standalone, traditional replication protocols such as Primary-Backup, Paxos, and PBFT are not directly applicable, as they were designed for the client-server model. When services interact, these protocols run into a number of problems, affecting both correctness and performance.
In this paper, we rethink the design of replication protocols in the presence of interactions between services and introduce new techniques that accommodate such interactions safely and efficiently. Our evaluation shows that a prototype implementation of Aegean not only ensures correctness in the presence of service interactions, but can further improve throughput by an order of magnitude.