RTCAST: Lightweight multicast for real-time process groups

We propose a lightweight fault-tolerant multicast and mem-bership service for real-time process groups which may ex-change periodic and aperiodic messages. The service sup-ports bounded-time message transport, atomicity, and order for multicasts within a group of communicating processes in the presence of processor crashes and communication failures. It guarantees agreement on membership among the communicating processors, and ensures that member-ship changes (e.g., resulting from processor joins or depar-tures) are atomic and ordered with respect to multicast mes-sages. We provide the flexibility of an event-triggered ap-proach with the fast message delivery time of time-triggered protocols, such as TTP [14], where messages are deliv-ered to the application immediately upon reception. This is achieved without compromising agreement, order and atom-icity properties. In addition to the design and details of the algorithm, we describe our implementation of the proto-col using the x-Kernel protocol architecture running on RT Mach 3.0. 1