http://www.rfc-editor.org/rfc/rfc2524.txt
RFC 2524: Neda's Efficient Mail Submission and Delivery (EMSD) Protocol Specification Version 1.3, M. Banan1999-02-01T23:00:00-00:00This specification narrowly focuses on submission and delivery of short mail messages with a clear emphasis on efficiency. This memo provides information for the Internet community.