Towards Byzantine fault tolerant publish/subscribe: a state machine approach

More than a decade of research has gone into techniques aimed at tolerating arbitrary failures in client/server interaction, using consensus based replication. These works made Byzantine fault tolerance possible [5], competitive [18], robust [7], and feasible to apply [6]. In this paper we establish a connection between the pub/sub interaction model and consensus based replication protocols, that makes the above results applicable to the design of large scale event-based middleware. We propose a Byzantine fault tolerant pub/sub system, on a tree-based overlay, tolerating a configurable number of failures in any part of the system, with minimal divergence from traditional pub/sub specifications and forwarding schemes.