Delayed Delivery

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Delayed Delivery This document defines an XMPP protocol extension for communicating the fact that an XML stanza has been delivered with a delay. &LEGALNOTICE; 0203 Experimental Standards Track Standards Council XMPP Core XEP-0082 XEP-0091 Not yet assigned &stpeter; 0.1 2006-12-20 psa

Initial version.

0.0.1 2006-12-19 psa First draft.

Although the XMPP protocol extension defined in &xep0091; provides a way to communicate that an XML stanza (typically a &MESSAGE; or &PRESENCE; stanza) has been delivered with a delay, the timestamp format defined in that document does not adhere to the recommended date and time profiles for XMPP protocols defined in &xep0082;. Therefore, this document defines a replacement for XEP-0091 which enables communication of delayed delivery information while adhering to XEP-0082.

The XML namespace defined herein is used to provide timestamp information about data stored for later delivery. The most common uses of this namespace are to stamp:

A message that is sent to an offline entity and stored for later delivery (see &xep0160;).
The last available presence stanza sent by a connected client to a server.
Messages cached by a &xep0045; room for delivery to new participants when they join the room.

Information about the delivery delay is communicated by adding to the <message/> or <presence/> stanza one and only one <delay/> child qualified by a namespace to be issued when this specification advances to a status of Draft. This information is added by the server or component that delivers the stanza. The following attributes are defined for the <delay/> element:

Element	Definition	Inclusion
<from/>	The Jabber ID of the entity that originally sent the XML stanza or that delayed the delivery of the stanza (e.g., the address of a multi-user chat room).	RECOMMENDED
<stamp/>	The time when the XML stanza was originally sent. The format MUST adhere to the dateTime format specified in XEP-0082 and MUST be expressed in UTC.	REQUIRED

In addition, the <delay/> element MAY contain XML character data that provides a natural-language description of the reason for the delay.

O blessed, blessed night! I am afeard. Being in night, all this is but a dream, Too flattering-sweet to be substantial. Offline Storage ]]> anon! xa 1 ]]> By the pricking of my thumbs, Something wicked this way comes. Open, locks, Whoever knocks! ]]>

This protocol was designed in a way that makes migration from XEP-0091 straightforward. All attributes present in the 'jabber:x:delay' namespace are present in the namespace defined herein. However, this document specifies a different format for the value of the <stamp> attribute (compliant with XEP-0082).

Implementations that support XEP-0091 should support the protocol defined herein as soon as possible, but should continue to support the protocol defined in XEP-0091 for backwards compatibility until the status of that specification is changed to Obsolete.

Delayed delivery data can expose information about the sender's presence on the network at some time in the past. However, this introduces no new vulnerabilities, since the same information would have been available in real time.

This document requires no interaction with &IANA;.

Until this specification advances to a status of Draft, its associated namespace shall be "http://www.xmpp.org/extensions/xep-0203.html#ns"; upon advancement of this specification, the XMPP Registrar shall issue a permanent namespace in accordance with the process defined in Section 4 of &xep0053;.

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