 Note that total order is not equivalent to FIFO order, which requires that if a process sent message 1 before it sent message 2, then all participants must receive message 1 before receiving message 2.It is also not equivalent to "causal order", where message 2 "depends on" or "occurs after" message 1 then all participants must receive message 2 after receiving message 1.While a strong and useful condition, total order requires only that all participants receive the messages in the same order, but does not place other constraints on that order.