Indicating Supported Media Features Using Extensions to DSN and MDN (RFC2530)
Original Publication Date: 1999-Mar-01
Included in the Prior Art Database: 2000-Sep-13
Internet Society Requests For Comment (RFCs)
There is a need in Internet mail and Internet fax for a recipient to indicate the media features it supports so that messages can be generated by senders without exceeding the recipient's abilities.
Network Working Group D. Wing
Request for Comments: 2530 Cisco Systems
Category: Standards Track March 1999
Indicating Supported Media Features Using
Extensions to DSN and MDN
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright (C) The Internet Society (1999). All Rights Reserved.
There is a need in Internet mail and Internet fax for a recipient to
indicate the media features it supports so that messages can be
generated by senders without exceeding the recipient's abilities.
This memo describes a format for generating Message Disposition
Notifications [RFC2298] and Delivery Status Notifications [RFC1894]
which contain such information. This information can be used by
senders to avoid exceeding the recipient's capabilities when sending
The extensions described in this document can be used in Message
Disposition Notifications [RFC2298] or Delivery Status Notifications
[RFC1894], as appropriate for the implementation.
Note that both DSNs and MDNs have drawbacks: DSNs are not available
between all senders and receivers, and MDNs require the receiver to
disclose message disposition information (or, if using the "denied"
disposition-type, the time the disposition notification was
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
3. Extensions for use by DSN and MDN
The following extension is available to both DSN [RFC1894] and MDN
For a DSN message, the following per-recipient fields are defined
(section 2.3 of [RFC1894]). For an MDN message, the following
extension fields are defined (section 3.1 of [RFC2298]). Using the
language of [RFC2234]:
extension-field = media-features CRLF
media-features = "Media-Accept-Features" ":"
media-feature-tags = <*text as defined below,
with LWSP wrapping>