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message ID

A number or string that uniquely names one message so a receiver can spot a repeat.

A message ID (often a per-device sequence number) lets a receiver remember what it has already processed and skip duplicates that at-least-once delivery produces.

Examples

  • A server that has seen up to sequence number 41 processes 42, then skips the resent 42 and the resent 40.

  • The command "dispense job 812: 5 L" carries the ID 812, so a second copy is recognized and skipped.

See also

idempotent exactly-once processing sequence number
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