Services for safety-critical applications on dual-scheduled TDMA networks

Tese de doutoramento. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 200

Low-overhead Time-Triggered Group Membership

. A group membership protocol is presented and proven correct for a synchronous time-triggered model of computation with processors in a ring that broadcast in turn. The protocol, derived from one used for critical control functions in automobiles, accepts a very restrictive fault model to achieve low overhead and requires only one bit of membership information piggybacked on regular broadcasts. Given its strong fault model, the protocol guarantees that a faulty processor will be promptly diagnosed and removed from the agreed group of processors, and will also diagnose itself as faulty. The protocol is correct under a fault-arrival assumption that new faults arrive at least n+1 time units apart, when there are n processors. Exploiting this assumption leads to unusual real-time reasoning in the correctness proof. 1 Introduction and Motivation Group membership has become an important abstraction in providing faulttolerant services for distributed systems [2]. As in any proto..