AS2

How it works

AS2 is how many retailers and factories exchange EDI. The payload is often encrypted and signed. The MDN is the proof of receipt. It is not SFTP, though partners offer both.

A supplier posts an 8 MB EDI document by AS2. The retailer's MDN returns in seconds, signed, naming the payload id. A later dispute uses the MDN, not a phone call. An SFTP drop of the same file has no MDN unless someone built one.

How it differs

AS2 is not AS4. AS4 is the SOAP successor. Partners still say AS2 for both.

A sync MDN in the HTTP response dies if the connection drops. Async MDN comes later.

Know which you configured.

On the ticket

• The practical close is a log line: time, actor, byte count, result.
• Without that line the transfer is a story.
• With it, the next person can see whether this door did what the ticket claimed.
• If the path is shared, say so in the partner profile so a later change does not silently pick a different limit, key, or region.
• On a real ticket, write down the door, the byte count, and the clock.
• For as2, that means naming the host or bucket, the expected size, and the time the other side must have a complete file.
• A progress bar is not that record.
• A 200 response that arrives before the complete call is not that record.
• If a retry is allowed, say how many and whether it resumes.
• If a person must approve the send, name the person.
• Partners who receive as2 files should match on hash or size before they import.
• A same-length corrupt file passes a size check and fails a hash.
• Keep the published hash off the only channel an attacker can edit, or treat it as a corruption check rather than a substitution check.
• When the path changes, new key, new region, new cap, update the profile the same day so the next run does not use a stale limit.