Distributed computing--notes (v)--Fault handling

Reliable communication

The nature of reliable multicast
-Validity: Messages sent are received
-Integrity: Received message is correct and not received two times
-Agreement: If a process passes m, other correct processes will eventually pass the M consensus definition: Each process starts with a pending state and proposes a value in the Set D; After the communication is made, it is agreed to use a final value. Requirements: Termination-The amount of decision to be used by each correct process; The same amount of decisions for each correct process; completeness-if the correct process proposes the same amount, eventually they will choose this value. Solving the consensus problem is equivalent to solving the problem of reliable full-sort multicast Byzantine general
A separate process provides a value, and other processes decide whether to take this value. The value provided is called the general, the other is the lieutenant. The Byzantine general problem assumes that the process is randomly faulted.
Modification of completeness: if the general's proposed value is correct, the other person will take this value.
"Not to be Continued"

Asynchronous systems cannot effectively achieve consistent recovery