Example Round Sample Clauses

Example Round. Figure 3 shows a sample ex- ecution of a single round of the BasicMCF protocol. The scenario depicted has three groups of agents, G1, G2, and G3. Even though the acceptor agents belong to these three groups, they are depicted outside the groups to make ex- plicit their message exchange; the location of the learners is irrelevant. No value has been proposed and no map- ping has been accepted in this execution of the protocol. Some messages unnecessary in a run without failures as well as the communication inside groups G2 and G3 were omitted to keep the figure simple. The coordinator of the round, one of the coordinators of group G1, starts the round by sending a 1A message to the acceptors and waiting for their 1B reply. Next, the coordinator sends a 2S message to the acceptors and all other coordinators of the round stating that nothing has yet been accepted. In an implementation of atomic broad- cast, these steps are executed for multiple instances of the protocol within the same message exchange, as explained in [37]. When a proposer of group G1 sends its proposal to its group’s coordinators, the later forward the proposal to the acceptors and coordinators of groups G2 and G3. Observe that in parallel, coordinators of G2 also send 2A messages to acceptors and coordinators, implying that a proposal was also made inside the group. The coordinators of G3, however, only send 2A after receiving the 2A from G1, and send their messages to the learners, implying that they have nothing to propose. Assuming that the proposal of G1 was {G1 '→ c} and the proposal of G2 was {G2 '→ d}, at the end of the round, the learners will learn the mapping (v : G1 → c, G2 → d, G3 → Nil ).