A group of four processes P0-P3 sends out multicasts in a run as shown below. The g...
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Problem
A group of four processes P0-P3 sends out multicasts in a run as shown below. The group is using causal ordering for multicasts. All sequence numbers start with zeros. The sequence vector at the end of the run at P2, as a comma-separated list (without the brackets), is:
Step-by-step solution
To determine the sequence vector at P2, we count the number of messages sent by each process that P2 has received or causally depends on. P2 receives M1 from P1 (seq 1), M3 from P0 (seq 3), and M4 from P3 (seq 1). P2 also receives M2 from P0 (seq 2). Thus, P2 has received 2 messages from P0, 3 from P1, 1 from P2, and 0 from P3.
Answer
2,3,1,0