Real systems, like Paxos or Isis 2  They use timeouts in various ways  Paxos: Waits until it has a majority of responses  FLP attack: disrupts leader until a timeout causes a new one to take over  We end up with a mix of 2-phase and 3-phase rounds  Isis 2 : Runs a protocol called Gbcast in the GMS  Basically a strong leader selection and then a 2-phase commit, with a 3-phase commit if leader fails  FLP attack: causes repeated changes in leader role; old leader forced to rejoin
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