The IESG has approved the following document: - 'Tunneling of SMTP Message Transfer Priorities' (draft-melnikov-smtp-priority-tunneling-04.txt) as Informational RFC This document has been reviewed in the IETF but is not the product of an IETF Working Group. The IESG contact person is Pete Resnick. A URL of this Internet Draft is: http://datatracker.ietf.org/doc/draft-melnikov-smtp-priority-tunneling/ Technical Summary This defines a mechanism for tunneling of SMTP (Simple Mail Transfer Protocol) Message Transfer Priority values through MTAs (Message Transfer Agents) that don't support the MT-PRIORITY SMTP extension. Working Group Summary There are currently no appropriate email-related working groups. The ADs and AppsAWG chairs considered the document for the Apps Area WG, but decided that it would be done best as an individual submission, and did not need the attention of the working group. Document Quality There is at least one prototype implementation, and plans for at least one other after publication. This is largely being done for a particular use case, and the proponents are aware of some of the tradeoffs they've made. The shepherd has some concern about the broader applicability of this as a standard, given those trade-offs. That said, some of them had to be made, and there is value in implementing features from proprietary email systems in standardized ways on the open Internet. The shepherd supports that general effort. Personnel Barry Leiba is the document shepherd Pete Resnick is the Responsible AD. RFC Editor note: Please make the following change to the Introduction: OLD: This document is an experimental extension to the SMTP Message Transfer Priorities extension [SMTP-PRIORITY]. It specifies application layer tunneling of message priority, to convey the priority of the messages through Message Transfer Agents (MTAs) that do not support the Message Transfer Priorities extension. The tunneling is done by adding a new message header field to Internet message format specified in [RFC5322]. NEW: The SMTP Message Transfer Priorities extension [SMTP-PRIORITY] specifies a mechanism to allow messages to be given a label to indicate preferential handling, to enable mail handling nodes to take this into account for onward processing. However, as with all SMTP extensions, all SMTP Message Transfer Agents (MTAs) between the source and the destination must support the extension in order for it to be successfully used. This document describes an application layer tunneling of message priority, to convey the priority of the messages through Message Transfer Agents (MTAs) that do not support the Message Transfer Priorities extension. The tunneling is done by adding a new message header field to Internet message format specified in [RFC5322].
