Duplicate Interchange Check

Operational EDI deduplication concept based on control numbers.

Definition

The receiver records the control numbers already accepted per partner and, on arrival, compares ISA13 (or the EDIFACT DE 0020). An already-seen value is treated as a duplicate — typically an AS2 retry or an OFTP2 restart — and the envelope is discarded without replaying the orders. This check is the concrete implementation of idempotency at the envelope level.

Origin

Relies on the control numbers defined by the ASC X12 Interchange Control Structures and by ISO 9735 (UN/EDIFACT); the receiving practice is described in partners' implementation guides and Interchange Agreements.

Example in context

Interchange ISA13=000004521 received twice (AS2 retry) → 1st time: accepted and processed; 2nd time: ISA13 already on record → rejected as duplicate, no order duplicated.

Related terms

• ISA13 — control number compared.
• Idempotency — property ensured by this check.