CIS 720 Broadcasting with failures Broadcasting with failures Type of failures link failures halting failures processor may crash and never recovers omission failures a processor may fail to ID: 764582
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CIS 720 Broadcasting with failures
Broadcasting with failures Type of failures: - link failures - halting failures: processor may crash and never recovers - omission failures: a processor may fail to send a message - byzantine failures
Broadcasting with failures P 1 has a value v1 to be sent to all other processes. Each process must deliver a message with value vj C1: If P1 is normal then each normal process Pj must eventually deliver vj, where v j = v1 C2: If any normal process Pj delivers vj, then every normal processs Pi must eventually deliver vi,, where vj = vi
C3: If any process P j delivers vj, then every normal process Pi must eventually deliver vi, where vi = vj
Reliable Broadcast 1 P 1 : send v1 to all processes; deliver v1Pj: receive vj; deliver vj
Reliable Broadcast 2 P 1 : send v1 to all processes; deliver v1Pj: receive vj; deliver vj; send vj to all processes
Reliable Broadcast 3 P 1 : send v1 to all processes; deliver v1Pj: receive vj; send vj to all processes; deliver v j;
Reliable Broadcast 4 At most t failures, where t < N/2 P 1: send v1 to all processes wait for at least N – t copies of the message deliver v 1 P j: receive vj; send vj to all processes wait for at least N - t copies of the message deliver vj
Byzantine failures Process may not follow the protocol It may send different values to different processes.