A fault tolerance framework for CORBA

We describe a fault tolerance framework for CORBA that provides fault tolerance management and core services, implemented above the ORB for ease of use and customization, and fault tolerance mechanisms, implemented beneath the ORB for transparency and efficiency. Strong replica consistency is facilitated by a multicast engine that provides reliable totally ordered delivery of multicast messages to the replicas of an object. Transparency to the application allows application programmers to focus on their applications rather than on fault tolerance, and transparency to the ORE allows existing commercial CORBA ORBs to be used without modification. The fault tolerance framework adheres to CORBA's objective of interoperability by ensuring that different implementations of the specifications of the framework can interoperate and that non-fault-tolerant objects can interwork with fault-tolerant objects.