2. Role of This Specification

This document presents the overview and framework for an approach to the next stage of email internationalization. This new stage requires not only internationalization of addresses and header fields, but also associated transport and delivery models. A prior version of this specification, RFC 4952 [RFC4952], also provided an introduction to a series of experimental protocols [RFC5335] [RFC5336] [RFC5337] [RFC5504] [RFC5721] [RFC5738] [RFC5825]. This revised form provides overview and conceptual information for the Standards Track successors of a subset of those protocols. Details of the documents and the relationships among them appear in Section 5 and a discussion of what was learned from the experimental protocols and their implementations appears in Section 6.

Taken together, these specifications provide the details for a way to implement and support internationalized email. The document itself describes how the various elements of email internationalization fit together and the relationships among the primary specifications associated with message transport, header formats, and handling.

This document, and others that comprise the collection described above, assume a reasonable familiarity with the basic Internet electronic mail specifications and terminology [RFC5321] [RFC5322] and the MIME [RFC2045] and 8BITMIME [RFC6152] ones as well. While not strictly required to implement this specification, a general familiarity with the terminology and functions of IDNA [RFC5890] [RFC5891] [RFC5892] [RFC5893] [RFC5894] are also assumed.