AS2 introduction

AS2 is a transport protocol specified in RFC 4130. AS2 version 1.1 adding compression is specified in RFC 5402. The MDN is specified in RFC 3798. Algorithm names are defined in RFC 5751 (S/MIME 3.2) which supersedes RFC 3851 (S/MIME 3.1);

Glossary

Term	Description	Comment
AS2	Applicability Statement 2
MDN	Message Disposition Notification	The transport level acknowledgement of AS2