Question

Alice and Bob are employees in your company who have each been given the task of inventing a failure detection algorithm for an asynchronous system that tolerates 3 simultaneous process failures. You are called to judge whether their protocols satisfy the requirement. Alice’s protocol has each process p randomly pick 3 other processes to send its heartbeats to, and thereafter p periodically sends its heartbeats to these processes. Bob’s protocol has each process p randomly pick 3 other processes to receive heartbeats from, and thereafter each of these 3 picked processes periodically send its heartbeats to p. Note that in each of these protocols, the heartbeats are direct ones rather than gossip-style.
Then, which of the following statements is correct? (

Answer 1

3 other processes to send its heartbeats to, and thereafter p periodically sends its heartbeats to these processes. Bob’s protocol has each process p randomly pick 3 other processes to receive heartbeats from, and thereafter each of these 3 picked processes periodically send its heartbeats to p. Note that in each of these protocols, the heartbeats are direct ones rather