draft-ietf-simple-imdn-10.txt   rfc5438.txt 
SIMPLE E. Burger Network Working Group E. Burger
Internet-Draft Request for Comments: 5438 Unaffiliated
Intended status: Standards Track H. Khartabil Category: Standards Track H. Khartabil
Expires: June 12, 2009 Ericsson Australia Ericsson Australia
December 09, 2008 January 2009
Instant Message Disposition Notification
draft-ietf-simple-imdn-10
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Abstract Abstract
Instant Messaging (IM) refers to the transfer of messages between Instant Messaging (IM) refers to the transfer of messages between
users in real-time. This document provides a mechanism whereby users in real-time. This document provides a mechanism whereby
endpoints can request Instant Message Disposition Notifications endpoints can request Instant Message Disposition Notifications
(IMDN), including delivery, processing, and displayed notifications, (IMDN), including delivery, processing, and display notifications,
for page-mode instant messages. for page-mode instant messages.
The Common Profile for Instant Messaging (CPIM) data format specified The Common Presence and Instant Messaging (CPIM) data format
in RFC 3862 is extended with new header fields that enable endpoints specified in RFC 3862 is extended with new header fields that enable
to request IMDNs. A new message format is also defined to convey endpoints to request IMDNs. A new message format is also defined to
IMDNs. convey IMDNs.
This document also describes how SIP entities behave using this This document also describes how SIP entities behave using this
extension. extension.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Disposition Types . . . . . . . . . . . . . . . . . . . . . . 6 5. Disposition Types . . . . . . . . . . . . . . . . . . . . . . 6
5.1. Delivery . . . . . . . . . . . . . . . . . . . . . . . . . 6 5.1. Delivery . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.2. Processing . . . . . . . . . . . . . . . . . . . . . . . . 7 5.2. Processing . . . . . . . . . . . . . . . . . . . . . . . . 7
5.3. Display . . . . . . . . . . . . . . . . . . . . . . . . . 7 5.3. Display . . . . . . . . . . . . . . . . . . . . . . . . . 7
6. New CPIM Header Fields . . . . . . . . . . . . . . . . . . . . 7 6. New CPIM Header Fields . . . . . . . . . . . . . . . . . . . . 8
6.1. CPIM Header Field Namespace . . . . . . . . . . . . . . . 7 6.1. CPIM Header Field Namespace . . . . . . . . . . . . . . . 8
6.2. Disposition-Notification . . . . . . . . . . . . . . . . . 8 6.2. Disposition-Notification . . . . . . . . . . . . . . . . . 8
6.3. Message-ID . . . . . . . . . . . . . . . . . . . . . . . . 8 6.3. Message-ID . . . . . . . . . . . . . . . . . . . . . . . . 8
6.4. Original-To . . . . . . . . . . . . . . . . . . . . . . . 9 6.4. Original-To . . . . . . . . . . . . . . . . . . . . . . . 9
6.5. IMDN-Record-Route . . . . . . . . . . . . . . . . . . . . 9 6.5. IMDN-Record-Route . . . . . . . . . . . . . . . . . . . . 9
6.6. IMDN-Route . . . . . . . . . . . . . . . . . . . . . . . . 9 6.6. IMDN-Route . . . . . . . . . . . . . . . . . . . . . . . . 9
7. Endpoint Behaviour . . . . . . . . . . . . . . . . . . . . . . 9 7. Endpoint Behaviour . . . . . . . . . . . . . . . . . . . . . . 10
7.1. IM Sender . . . . . . . . . . . . . . . . . . . . . . . . 9 7.1. IM Sender . . . . . . . . . . . . . . . . . . . . . . . . 10
7.1.1. Constructing Instant Messages . . . . . . . . . . . . 9 7.1.1. Constructing Instant Messages . . . . . . . . . . . . 10
7.1.2. Matching IMs with IMDNs . . . . . . . . . . . . . . . 11 7.1.2. Matching IMs with IMDNs . . . . . . . . . . . . . . . 11
7.1.3. Keeping State . . . . . . . . . . . . . . . . . . . . 11 7.1.3. Keeping State . . . . . . . . . . . . . . . . . . . . 12
7.1.4. Aggregation of IMDNs . . . . . . . . . . . . . . . . . 12 7.1.4. Aggregation of IMDNs . . . . . . . . . . . . . . . . . 12
7.2. IM Recipient . . . . . . . . . . . . . . . . . . . . . . . 12 7.2. IM Recipient . . . . . . . . . . . . . . . . . . . . . . . 13
7.2.1. Constructing IMDNs . . . . . . . . . . . . . . . . . . 12 7.2.1. Constructing IMDNs . . . . . . . . . . . . . . . . . . 13
8. Intermediary Behaviour . . . . . . . . . . . . . . . . . . . . 15 8. Intermediary Behaviour . . . . . . . . . . . . . . . . . . . . 15
8.1. Constructing Processing Notifications . . . . . . . . . . 16 8.1. Constructing Processing Notifications . . . . . . . . . . 16
8.2. Constructing Delivery Notifications . . . . . . . . . . . 17 8.2. Constructing Delivery Notifications . . . . . . . . . . . 17
8.3. Aggregation of IMDNs . . . . . . . . . . . . . . . . . . . 18 8.3. Aggregation of IMDNs . . . . . . . . . . . . . . . . . . . 18
9. Identifying Messages . . . . . . . . . . . . . . . . . . . . . 20 9. Identifying Messages . . . . . . . . . . . . . . . . . . . . . 20
10. Header Fields Formal Syntax . . . . . . . . . . . . . . . . . 20 10. Header Fields Formal Syntax . . . . . . . . . . . . . . . . . 20
11. IMDN Format . . . . . . . . . . . . . . . . . . . . . . . . . 21 11. IMDN Format . . . . . . . . . . . . . . . . . . . . . . . . . 21
11.1. Structure of XML-Encoded IMDN Payload . . . . . . . . . . 21 11.1. Structure of an XML-Encoded IMDN Payload . . . . . . . . . 21
11.1.1. The <message-id> Element . . . . . . . . . . . . . . . 22 11.1.1. The <message-id> Element . . . . . . . . . . . . . . . 22
11.1.2. The <datetime> Element . . . . . . . . . . . . . . . . 22 11.1.2. The <datetime> Element . . . . . . . . . . . . . . . . 22
11.1.3. The <recipient-uri> Element . . . . . . . . . . . . . 22 11.1.3. The <recipient-uri> Element . . . . . . . . . . . . . 22
11.1.4. The <original-recipient-uri> Element . . . . . . . . . 23 11.1.4. The <original-recipient-uri> Element . . . . . . . . . 23
11.1.5. The <subject> Element . . . . . . . . . . . . . . . . 23 11.1.5. The <subject> Element . . . . . . . . . . . . . . . . 23
11.1.6. The <delivery-notification>, 11.1.6. The <delivery-notification>,
<processing-notification> and <processing-notification>, and
<display-notification> Elements . . . . . . . . . . . 23 <display-notification> Elements . . . . . . . . . . . 23
11.1.7. The <status> Element . . . . . . . . . . . . . . . . . 23 11.1.7. The <status> Element . . . . . . . . . . . . . . . . . 23
11.1.8. MIME Type for IMDN Payload . . . . . . . . . . . . . . 23 11.1.8. MIME Type for IMDN Payload . . . . . . . . . . . . . . 23
11.1.9. The RelaxNG Schema . . . . . . . . . . . . . . . . . . 23 11.1.9. The RelaxNG Schema . . . . . . . . . . . . . . . . . . 23
12. Transporting Messages using SIP . . . . . . . . . . . . . . . 27 12. Transporting Messages Using SIP . . . . . . . . . . . . . . . 27
12.1. Endpoint Behaviour . . . . . . . . . . . . . . . . . . . . 27 12.1. Endpoint Behaviour . . . . . . . . . . . . . . . . . . . . 27
12.1.1. Sending Requests . . . . . . . . . . . . . . . . . . . 27 12.1.1. Sending Requests . . . . . . . . . . . . . . . . . . . 27
12.1.2. Sending Responses . . . . . . . . . . . . . . . . . . 28 12.1.2. Sending Responses . . . . . . . . . . . . . . . . . . 28
12.1.3. Receiving Requests . . . . . . . . . . . . . . . . . . 28 12.1.3. Receiving Requests . . . . . . . . . . . . . . . . . . 28
12.2. Intermediary Behaviour . . . . . . . . . . . . . . . . . . 29 12.2. Intermediary Behaviour . . . . . . . . . . . . . . . . . . 29
13. Transporting Messages using MSRP . . . . . . . . . . . . . . . 30 13. Transporting Messages using MSRP . . . . . . . . . . . . . . . 30
14. Security Considerations . . . . . . . . . . . . . . . . . . . 31 14. Security Considerations . . . . . . . . . . . . . . . . . . . 31
14.1. Forgery . . . . . . . . . . . . . . . . . . . . . . . . . 33 14.1. Forgery . . . . . . . . . . . . . . . . . . . . . . . . . 33
14.2. Confidentiality . . . . . . . . . . . . . . . . . . . . . 33 14.2. Confidentiality . . . . . . . . . . . . . . . . . . . . . 33
14.3. IMDN as a Certified Delivery Service . . . . . . . . . . . 34 14.3. IMDN as a Certified Delivery Service . . . . . . . . . . . 34
15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 34 15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 34
15.1. message/imdn+xml MIME TYPE . . . . . . . . . . . . . . . . 34 15.1. message/imdn+xml MIME TYPE . . . . . . . . . . . . . . . . 34
15.2. XML Registration . . . . . . . . . . . . . . . . . . . . . 35 15.2. XML Registration . . . . . . . . . . . . . . . . . . . . . 35
15.3. Registration for urn:ietf:params:imdn . . . . . . . . . . 35 15.3. URN Registration for IMDN Header Parameters . . . . . . . 36
15.4. Content-Disposition: notification . . . . . . . . . . . . 36 15.4. Content-Disposition: notification . . . . . . . . . . . . 37
16. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 36 16. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 37
17. References . . . . . . . . . . . . . . . . . . . . . . . . . . 37 17. References . . . . . . . . . . . . . . . . . . . . . . . . . . 37
17.1. Normative References . . . . . . . . . . . . . . . . . . . 37 17.1. Normative References . . . . . . . . . . . . . . . . . . . 37
17.2. Informative References . . . . . . . . . . . . . . . . . . 37 17.2. Informative References . . . . . . . . . . . . . . . . . . 38
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 38
Intellectual Property and Copyright Statements . . . . . . . . . . 39
1. Introduction 1. Introduction
In many user-to-user message exchange systems, message senders often In many user-to-user message exchange systems, message senders often
wish to know if the human recipient actually received a message or wish to know if the human recipient actually received a message or
has the message displayed. has the message displayed.
Electronic Mail [RFC2821] offers a solution to this need with Message Electronic mail [RFC5321] offers a solution to this need with Message
Delivery Notifications [RFC3798]. After the recipient views the Disposition Notifications [RFC3798]. After the recipient views the
message, her mail user agent generates a Message Delivery message, her mail user agent generates a Message Disposition
Notification, or MDN. The MDN is an e-mail that follows the format Notification, or MDN. The MDN is an email that follows the format
prescribed by RFC 3798 [RFC3798]. The fixed format ensures that an prescribed by RFC 3798 [RFC3798]. The fixed format ensures that an
automaton can process the message. automaton can process the message.
The common presence and instant messaging (CPIM) format, Message/CPIM The Common Presence and Instant Messaging (CPIM) format, Message/CPIM
[RFC3862], is a message format used to generate instant messages. [RFC3862], is a message format used to generate instant messages.
The session initiation protocol, SIP [RFC3261], can carry instant The Session Initiation Protocol (SIP [RFC3261]) can carry instant
messages generated using message/CPIM in SIP MESSAGE requests messages generated using message/CPIM in SIP MESSAGE requests
[RFC3428]. [RFC3428].
This document extends the Message/CPIM message format in much the This document extends the Message/CPIM message format in much the
same way Message Delivery Notifications extends Electronic Mail. same way Message Disposition Notifications extends electronic mail.
This extension enables Instant Message Senders to request, create, This extension enables Instant Message Senders to request, create,
and send Instant Message Disposition Notifications (IMDN). This and send Instant Message Disposition Notifications (IMDN). This
mechanism works for page-mode as well as session mode instant mechanism works for page-mode as well as session-mode instant
messages. This document only discusses page-mode. Session mode is messages. This document only discusses page-mode. Session-mode is
left for future standardisation efforts. left for future standardisation efforts.
This specification defines three categories of disposition types, This specification defines three categories of disposition types:
"delivery", "processing", and "displayed". Specific disposition "delivery", "processing", and "display". Specific disposition types
types provide more detailed information. For example, the "delivery" provide more detailed information. For example, the "delivery"
category includes "delivered" to indicate successful delivery and category includes "delivered" to indicate successful delivery and
"failed" to indicate failure in delivery. "failed" to indicate failure in delivery.
2. Conventions 2. Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
This document refers generically to the sender of a message in the This document refers generically to the sender of a message in the
skipping to change at page 5, line 8 skipping to change at page 5, line 8
This document refers generically to the sender of a message in the This document refers generically to the sender of a message in the
masculine (he/him/his) and the recipient of the message in the masculine (he/him/his) and the recipient of the message in the
feminine (she/her/hers). This convention is purely for convenience feminine (she/her/hers). This convention is purely for convenience
and makes no assumption about the gender of a message sender or and makes no assumption about the gender of a message sender or
recipient. recipient.
3. Terminology 3. Terminology
o IM: An Instant Message generated using the Message/CPIM format. o IM: An Instant Message generated using the Message/CPIM format.
o IMDN: An Instant Message Disposition Notification generated using o IMDN: An Instant Message Disposition Notification generated using
the Message/CPIM format that carries an IMDN XML document. the Message/CPIM format that carries an IMDN XML document.
o Message: an IM or an IMDN generated using the Message/CPIM format.
o IM Sender: An endpoint (User Agent) generating and sending an IM. o Message: An IM or an IMDN generated using the Message/CPIM format.
o IM Sender: An endpoint (user agent) generating and sending an IM.
Also, the endpoint request IMDNs for an IM. Quite often, the IM Also, the endpoint request IMDNs for an IM. Quite often, the IM
Sender is the IMDN Recipient. However, that is not always the Sender is the IMDN Recipient. However, that is not always the
case, since the IMDN uses the From header in the CPIM message. case, since the IMDN uses the From header in the CPIM message.
That value is often the IM Sender's Address of Record (AOR). This That value is often the IM Sender's Address of Record (AOR). This
address may in fact resolve to different User Agents. address may in fact resolve to different user agents.
o IM Recipient: An endpoint (User Agent) that receives IMs. The IM
o IM Recipient: An endpoint (user agent) that receives IMs. The IM
Recipient, as the node that presumably renders the IM to the user, Recipient, as the node that presumably renders the IM to the user,
generates and sends delivery IMDNs to IMs, if requested by the IM generates and sends delivery IMDNs to IMs, if requested by the IM
Sender and allowed by the IM Recipient. Sender and allowed by the IM Recipient.
o Endpoint: An IM Sender or an IM Recipient. o Endpoint: An IM Sender or an IM Recipient.
o Intermediary: An entity in the network, most often an application o Intermediary: An entity in the network, most often an application
server, including URI-List servers and Store-and-Forward servers, server (including URI-List and store-and-forward servers), that
that forwards an IM to its final destination. Intermediaries also forwards an IM to its final destination. Intermediaries also can
can generate and send processing IMDNs to IMs, if requested by the generate and send processing IMDNs to IMs, if requested by the IM
IM Sender and allowed by policy. Sender and allowed by policy.
o Gateway: An intermediary that translates between different IM o Gateway: An intermediary that translates between different IM
systems that use different protocols. systems that use different protocols.
o IMDN Payload: An XML document carrying the disposition
o IMDN payload: An XML document carrying the disposition
notification information. In this specification, it is of MIME notification information. In this specification, it is of MIME
type "message/imdn+xml". type "message/imdn+xml".
o Disposition type: the type of IMDN that can be requested. This
specification defines three categories of disposition types, o Disposition type: This specification defines three categories of
"delivery", "processing", and "display". disposition types: "delivery", "processing", and "display".
o Transport Protocol Message: A SIP or other protocol message that o Transport Protocol Message: A SIP or other protocol message that
contains an IM or IMDN. contains an IM or IMDN.
4. Overview 4. Overview
The diagram below shows the basic protocol flow. An IM Sender The diagram below shows the basic protocol flow. An IM Sender
creates an IM, adds IMDN request information the IM Sender is creates an IM, adds IMDN request information that the IM Sender is
interested in receiving and then sends the IM. At a certain point in interested in receiving, and then sends the IM. At a certain point
time, the IM Recipient or an intermediary determines that the user or in time, the IM Recipient or an intermediary determines that the user
application has received, did not receive, displayed, or otherwise or application has received, did not receive, displayed, or otherwise
disposed the IM. The mechanism by which an IM Recipient determines disposed of the IM. The mechanism by which an IM Recipient
its user has read an IM is beyond the scope of this document. At determines its user has read an IM is beyond the scope of this
that point, the IM Recipient or intermediary automatically generates document. At that point, the IM Recipient or intermediary
a notification message to the IM Sender. This notification message automatically generates a notification message to the IM Sender.
is the Instant Message Disposition Notification (IMDN). This notification message is the Instant Message Disposition
Notification (IMDN).
+--------------+ +--------------+ +--------------+ +--------------+
| IM Sender | | IM Recipient | | IM Sender | | IM Recipient |
|IMDN Recipient| | IMDN Sender | |IMDN Recipient| | IMDN Sender |
+--------------+ +--------------+ +--------------+ +--------------+
| | | |
| | | |
| 1. IM requesting IMDN | | 1. IM requesting IMDN |
|-------------------------------------->| |-------------------------------------->|
| | | |
| | | |
| 2. IMDN (disposition) | | 2. IMDN (disposition) |
|<--------------------------------------| |<--------------------------------------|
| | | |
| | | |
Basic IMDN Message Flow Basic IMDN Message Flow
Note the recipient of an IMDN, in some instances, may not be the IM Note the recipient of an IMDN, in some instances, may not be the IM
Sender. This is specifically true for page-mode IMs where the Sender. This is specifically true for page-mode IMs where the
Address of Record (AOR) of the IM Sender, that is present in the IM, Address of Record (AOR) of the IM Sender, which is present in the IM,
resolves to a different location or user agent than the IM resolves to a different location or user agent than that from which
originated. This could happen, for example, if resolving the AOR the IM originated. This could happen, for example, if resolving the
results in forking the request to multiple user agents. For AOR results in forking the request to multiple user agents. For
simplicity, the rest of this document assumes that the IM Sender and simplicity, the rest of this document assumes that the IM Sender and
the IMDN Recipient are the same and therefore will refer to both as the IMDN Recipient are the same and therefore will refer to both as
the IM Sender. the IM Sender.
5. Disposition Types 5. Disposition Types
There are three broad categories of disposition states. They are There are three broad categories of disposition states. They are
delivery, processing, and display. delivery, processing, and display.
5.1. Delivery 5.1. Delivery
The delivery notification type indicates whether the IM has been The delivery notification type indicates whether or not the IM has
delivered to the IM Recipient or not. The delivery notification type been delivered to the IM Recipient. The delivery notification type
can have the following states: can have the following states:
o "delivered" to indicate successful delivery. o "delivered" to indicate successful delivery.
o "failed" to indicate failure in delivery. o "failed" to indicate failure in delivery.
o "forbidden" indicate denial for the IM Sender to receive the
o "forbidden" to indicate denial for the IM Sender to receive the
requested IMDN. The IM Recipient can send the "forbidden" state, requested IMDN. The IM Recipient can send the "forbidden" state,
but usually it is an intermediary that sends the message if one but usually it is an intermediary that sends the message, if one
configures it to do so. For example, it is possible the configures it to do so. For example, it is possible the
administrator has disallowed IMDNs. administrator has disallowed IMDNs.
o "error" to indicate an error in determining the fate of an IM. o "error" to indicate an error in determining the fate of an IM.
5.2. Processing 5.2. Processing
The processing notification type indicates that an intermediary has The processing notification type indicates that an intermediary has
processed an IM. The processing notification type can have the processed an IM. The processing notification type can have the
following states: following states:
o "processed" is a general state of the IM indicating that the
intermediary has performed its task on the IM. o "processed" to indicate that the intermediary has performed its
o "stored" state indicates that the intermediary stored the IM for task on the IM. This is a general state of the IM.
later delivery.
o "forbidden" indicate denial for the IM Sender to receive the o "stored" to indicate that the intermediary stored the IM for later
delivery.
o "forbidden" to indicate denial for the IM Sender to receive the
requested IMDN. The "forbidden" state is sent by an intermediary requested IMDN. The "forbidden" state is sent by an intermediary
that is configured to do so. For example, the administrator has that is configured to do so. For example, the administrator has
disallowed IMDNs. disallowed IMDNs.
o "error" to indicate an error in determining the fate of an IM. o "error" to indicate an error in determining the fate of an IM.
5.3. Display 5.3. Display
The display notification type indicates whether the IM Recipient The display notification type indicates whether or not the IM
rendered the IM to the user or not. The display notification type Recipient rendered the IM to the user. The display notification type
can have the following states: can have the following states:
o "displayed" is a state indicating that the IM has been rendered to
the user. o "displayed" to indicate that the IM has been rendered to the user.
o "forbidden" indicate denial, by the IM Recipient, for the IM
o "forbidden" to indicate denial, by the IM Recipient, for the IM
Sender to receive the requested IMDN. Sender to receive the requested IMDN.
o "error" to indicate an error in determining the fate of an IM. o "error" to indicate an error in determining the fate of an IM.
In addition to text, some IMs may contain audio, video, and still In addition to text, some IMs may contain audio, video, and still
images. Therefore, the state "displayed" includes the start of images. Therefore, the state "displayed" includes the start of
rendering the audio or video file to the user. rendering the audio or video file to the user.
Since there is no positive acknowledgement from the user, one cannot Since there is no positive acknowledgement from the user, one cannot
determine the user actually read the IM. Thus, one cannot use the determine if the user actually read the IM. Thus, one cannot use the
protocol described here as a service to prove someone actually read protocol described here as a service to prove someone actually read
the IM. the IM.
6. New CPIM Header Fields 6. New CPIM Header Fields
This specification extends the CPIM data format specified in RFC 3862 This specification extends the CPIM data format specified in RFC 3862
[RFC3862]. A new name space is created as well as a number of new [RFC3862]. A new name space is created as well as a number of new
CPIM header fields. CPIM header fields.
6.1. CPIM Header Field Namespace 6.1. CPIM Header Field Namespace
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6. New CPIM Header Fields 6. New CPIM Header Fields
This specification extends the CPIM data format specified in RFC 3862 This specification extends the CPIM data format specified in RFC 3862
[RFC3862]. A new name space is created as well as a number of new [RFC3862]. A new name space is created as well as a number of new
CPIM header fields. CPIM header fields.
6.1. CPIM Header Field Namespace 6.1. CPIM Header Field Namespace
Per CPIM [RFC3862], this specification defines a new name space for Per CPIM [RFC3862], this specification defines a new name space for
the CPIM extension header fields defined in the following sections. the CPIM extension header fields defined in the following sections.
The name space is: The name space is:
urn:ietf:params:imdn urn:ietf:params:imdn
As per CPIM [RFC3862] requirements, the new header fields defined in As per CPIM [RFC3862] requirements, the new header fields defined in
the following sections are prepended, in CPIM messages, by a prefix the following sections are prepended, in CPIM messages, by a prefix
assigned to the URN through the NS header field of the CPIM message. assigned to the URN through the NS header field of the CPIM message.
The remaining of this specification always assumes an NS header field The remainder of this specification always assumes an NS header field
like this one: like this one:
NS: imdn <urn:ietf:params:imdn>. NS: imdn <urn:ietf:params:imdn>.
Of course, clients are free to use any prefix while servers and Of course, clients are free to use any prefix while servers and
intermediaries must accept any legal name space prefix specification. intermediaries must accept any legal name space prefix specification.
6.2. Disposition-Notification 6.2. Disposition-Notification
The IM Sender MUST include the Disposition-Notification header field The IM Sender MUST include the Disposition-Notification header field
to indicate the desire to receive IMDNs from the IM Recipient, for to indicate the desire to receive IMDNs from the IM Recipient for
that specific IM. Section 10 defines the syntax. that specific IM. Section 10 defines the syntax.
6.3. Message-ID 6.3. Message-ID
The IM Sender MUST include the Message-ID header field in the IM that The IM Sender MUST include the Message-ID header field in the IM for
he wishes to receive an IMDN on. The Message-ID contains a globally which he wishes to receive an IMDN. The Message-ID contains a
unique message identifier the IM Sender can use to correlate received globally unique message identifier that the IM Sender can use to
IMDNs. Because the Message-ID is used by the sender to correlate correlate received IMDNs. Because the Message-ID is used by the
IMDNs with their respective IMs, the Message-ID MUST be selected so sender to correlate IMDNs with their respective IMs, the Message-ID
that: MUST be selected so that:
o There is a minimal chance of any two Message-IDs accidentally o There is a minimal chance of any two Message-IDs accidentally
colliding within the time period within which an IMDN might be colliding during the time period within which an IMDN might be
received. received.
o It is prohibitive for an attacker who has seen one or more valid o It is prohibitive for an attacker who has seen one or more valid
Message-IDs to generate additional valid Message-IDs. Message-IDs to generate additional valid Message-IDs.
The first requirement is a correctness requirement to ensure correct The first requirement is a correctness requirement to ensure correct
matching by the sender. The second requirement prevents off-path matching by the sender. The second requirement prevents off-path
attackers from forging IMDNs. In order to meet both of these attackers from forging IMDNs. In order to meet both of these
requirements, it is RECOMMENDED that Message-IDs be generated using a requirements, it is RECOMMENDED that Message-IDs be generated using a
cryptographically secure pseudorandom number generator and contain at cryptographically secure, pseudo-random number generator and contain
least 64 bits of randomness, thus reducing the chance of a successful at least 64 bits of randomness, thus reducing the chance of a
guessing attack to n/2^64, where n is the number of outstanding valid successful guessing attack to n/2^64, where n is the number of
messages. outstanding valid messages.
When the IM Sender receives an IMDN, it can compare its value with When the IM Sender receives an IMDN, it can compare its value with
the value of the <message-id> element present in the IMDN payload. the value of the <message-id> element present in the IMDN payload.
IMDNs also carry this header field. Note that since the IMDN is IMDNs also carry this header field. Note that since the IMDN is
itself an IM, the Message-ID of the IMDN will be different than the itself an IM, the Message-ID of the IMDN will be different than the
Message-ID of the original IM. Section 10 defines the syntax. Message-ID of the original IM. Section 10 defines the syntax.
6.4. Original-To 6.4. Original-To
An intermediary MAY insert an Original-To header field to the IM. An intermediary MAY insert an Original-To header field into the IM.
The value of the Original-To field MUST be the address of the IM The value of the Original-To field MUST be the address of the IM
Receiver. The IM Recipient uses this header to indicate the original Receiver. The IM Recipient uses this header to indicate the original
IM address in the IMDNs. The IM Recipient does this by populating IM address in the IMDNs. The IM Recipient does this by populating
the <original-recipient-uri> element in the IMDN. The intermediary the <original-recipient-uri> element in the IMDN. The intermediary
MUST insert this header if the intermediary changes the CPIM To MUST insert this header if the intermediary changes the CPIM To
header field value. The header field MUST NOT appear more than once header field value. The header field MUST NOT appear more than once
in an IM. The intermediary MUST NOT change this header field value in an IM. The intermediary MUST NOT change this header field value
if it is already present. Section 10 defines the syntax. if it is already present. Section 10 defines the syntax.
6.5. IMDN-Record-Route 6.5. IMDN-Record-Route
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An intermediary MAY insert an IMDN-Record-Route header field to the An intermediary MAY insert an IMDN-Record-Route header field to the
IM. This enables the intermediary to receive and process the IMDN on IM. This enables the intermediary to receive and process the IMDN on
its way back to the IM Sender. The value of the IMDN-Record-Route its way back to the IM Sender. The value of the IMDN-Record-Route
header field MUST be the address of the intermediary. Multiple IMDN- header field MUST be the address of the intermediary. Multiple IMDN-
Record-Route header fields can appear in an IM. Section 10 defines Record-Route header fields can appear in an IM. Section 10 defines
the syntax. the syntax.
6.6. IMDN-Route 6.6. IMDN-Route
The IMDN-Route header field provides routing information by including The IMDN-Route header field provides routing information by including
one or more addresses where to route the IMDN. An intermediary that one or more addresses to which to route the IMDN. An intermediary
needs the IMDN to flow back through the same intermediary MUST add that needs the IMDN to flow back through the same intermediary MUST
the IMDN-Record-Route header. When the IM Recipient creates the add the IMDN-Record-Route header. When the IM Recipient creates the
corresponding IMDN, the IM Recipient copies the IMDN-Record-Route corresponding IMDN, the IM Recipient copies the IMDN-Record-Route
headers into corresponding IMDN-Route header fields. Section 10 headers into corresponding IMDN-Route header fields. Section 10
defines the syntax. defines the syntax.
7. Endpoint Behaviour 7. Endpoint Behaviour
7.1. IM Sender 7.1. IM Sender
7.1.1. Constructing Instant Messages 7.1.1. Constructing Instant Messages
An IM is constructed using CPIM Message Format defined in RFC 3862 An IM is constructed using the CPIM message format defined in RFC
[RFC3862]. 3862 [RFC3862].
7.1.1.1. Adding a Message-ID Header Field 7.1.1.1. Adding a Message-ID Header Field
If the IM sender requests the reception of IMDNs, the IM sender MUST If the IM Sender requests the reception of IMDNs, the IM Sender MUST
include a Message-ID header field. This header field enables the IM include a Message-ID header field. This header field enables the IM
Sender to match any IMDNs with their corresponding IMs. See Sender to match any IMDNs with their corresponding IMs. See
Section 6.3 for Message-ID uniqueness requirements. Section 6.3 for Message-ID uniqueness requirements.
7.1.1.2. Adding a DateTime Header Field 7.1.1.2. Adding a DateTime Header Field
Some devices are not able to retain state over long periods. For Some devices are not able to retain state over long periods. For
example, mobile devices may have memory limits or battery limits. example, mobile devices may have memory or battery limits. Such
These limits may mean these devices may not be able to, or may chose limits mean these devices may not be able to, or may choose not to,
not to, keep sent messages for the purposes of correlating IMDNs with keep sent messages for the purposes of correlating IMDNs with sent
sent IMs. To make some use of IMDN in this case, we add a time stamp IMs. To make some use of IMDN in this case, we add a time stamp to
to the IM to indicate when the user sent the message. The IMDN the IM to indicate when the user sent the message. The IMDN returns
returns this time stamp to enable the user to correlate the IM with this time stamp to enable the user to correlate the IM with the IMDN
the IMDN at the human level. We use the DateTime CPIM header field at the human level. We use the DateTime CPIM header field for this
for this purpose. Thus, if the IM Sender would like an IMDN, the IM purpose. Thus, if the IM Sender would like an IMDN, the IM Sender
Sender MUST include the DateTime CPIM header field. MUST include the DateTime CPIM header field.
7.1.1.3. Adding a Disposition-Notification Header Field 7.1.1.3. Adding a Disposition-Notification Header Field
The Disposition-Notification conveys the type of disposition The Disposition-Notification conveys the type of disposition
notification requested by the IM sender. There are three types of notification requested by the IM Sender. There are three types of
disposition notification: delivery, processing, and display. The disposition notification: delivery, processing, and display. The
delivery notification is further subdivided into failure and success delivery notification is further subdivided into failure and success
delivery notifications. An IM Sender requests failure delivery delivery notifications. An IM Sender requests failure delivery
notification by including a Disposition-Notification header field notification by including a Disposition-Notification header field
with value "negative-delivery". Similarly, a success notification is with value "negative-delivery". Similarly, a success notification is
requested by including a Disposition-Notification header field with requested by including a Disposition-Notification header field with
value "positive-delivery". The IM Send can request both types of value "positive-delivery". The IM Sender can request both types of
delivery notifications for the same IM. delivery notifications for the same IM.
The IM Sender can request a processing notification by including a The IM Sender can request a processing notification by including a
Disposition-Notification header field with value "processing". Disposition-Notification header field with value "processing".
The IM Sender can also request a display notification. The IM Sender The IM Sender can also request a display notification. The IM Sender
MUST include a Disposition-Notification header field with the value MUST include a Disposition-Notification header field with the value
"display" to request a display IMDN. "display" to request a display IMDN.
The absence of this header field or the presence of the header field The absence of this header field or the presence of the header field
with an empty value indicates that the IM Sender is not requesting with an empty value indicates that the IM Sender is not requesting
any IMDNs. Disposition-Notification header field values are comma any IMDNs. Disposition-Notification header field values are comma-
separated. The IM Sender MAY request more than one type of IMDN for separated. The IM Sender MAY request more than one type of IMDN for
a single IM. a single IM.
Future extensions may define other disposition notifications not Future extensions may define other disposition notifications not
defined in this document. defined in this document.
Section 10 describes the formal syntax for the Disposition- Section 10 describes the formal syntax for the Disposition-
Notification header field. The following is an example CPIM body of Notification header field. The following is an example CPIM body of
an IM where the IM Sender requests positive and negative delivery an IM where the IM Sender requests positive and negative delivery
notifications, but neither display notification nor processing notifications, but not display notification or processing
notifications: notifications:
From: Alice <im:alice@example.com> From: Alice <im:alice@example.com>
To: Bob <im:bob@example.com> To: Bob <im:bob@example.com>
NS: imdn <urn:ietf:params:imdn> NS: imdn <urn:ietf:params:imdn>
imdn.Message-ID: 34jk324j imdn.Message-ID: 34jk324j
DateTime: 2006-04-04T12:16:49-05:00 DateTime: 2006-04-04T12:16:49-05:00
imdn.Disposition-Notification: positive-delivery, negative-delivery imdn.Disposition-Notification: positive-delivery, negative-delivery
Content-type: text/plain Content-type: text/plain
Content-length: 12 Content-length: 12
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An IM Sender matches an IMDN to an IM by matching the Message-ID An IM Sender matches an IMDN to an IM by matching the Message-ID
header field value in the IM with the <message-id> element value in header field value in the IM with the <message-id> element value in
the body of the IMDN. If the IM was delivered to multiple the body of the IMDN. If the IM was delivered to multiple
recipients, the IM Sender uses the <recipient-uri> element and the recipients, the IM Sender uses the <recipient-uri> element and the
<original-recipient-uri> element in the XML body of the IMDN it <original-recipient-uri> element in the XML body of the IMDN it
received to determine if the IM was sent to multiple recipients and received to determine if the IM was sent to multiple recipients and
to identify the IM Recipient that sent the IMDN. to identify the IM Recipient that sent the IMDN.
An IM Sender can determine an IMDN is a disposition notification by An IM Sender can determine an IMDN is a disposition notification by
noting the Content-Disposition in the IMDN is "notification". This noting if the Content-Disposition in the IMDN is "notification".
does mean the IM Sender MUST understand the Content-Disposition MIME This does mean the IM Sender MUST understand the Content-Disposition
header in CPIM messages. MIME header in CPIM messages.
7.1.3. Keeping State 7.1.3. Keeping State
This specification does not mandate the IM Sender to keep state for a This specification does not mandate the IM Sender to keep state for a
sent IM. sent IM.
Once an IM Sender sends an IM containing an IMDN request, it MAY Once an IM Sender sends an IM containing an IMDN request, it MAY
preserve the IM context, principally the Message-ID, and other user- preserve the IM context (principally the Message-ID), other user-
identifiable information such as the IM subject or content, and date identifiable information such as the IM subject or content, and the
and time it was sent. Without preservation of the IM context, the IM date and time it was sent. Without preservation of the IM context,
Sender will not be able to correlate the IMDN with the IM it sent. the IM Sender will not be able to correlate the IMDN with the IM it
The IM Sender may find it impossible to preserve IM state if it has sent. The IM Sender may find it impossible to preserve IM state if
limited resources or does not have non-volatile memory and then loses it has limited resources or does not have non-volatile memory and
power. then loses power.
There is, however, the concept of "Sent Items" box in an application There is, however, the concept of a "Sent Items" box in an
that stores sent IMs. This "Sent Items" box has the necessary application that stores sent IMs. This "Sent Items" box has the
information and may have a fancy user interface indicating the state necessary information and may have a fancy user interface indicating
of a sent IM. A unique Message-ID for this purpose proves to be the state of a sent IM. A unique Message-ID for this purpose proves
useful. The length of time for items to remain in the "Sent Items" to be useful. The length of time for items to remain in the "Sent
box is a user choice. The user is usually free to keep or delete Items" box is a user choice. The user is usually free to keep or
items from the "Sent Items" box as she pleases or as the memory on delete items from the "Sent Items" box as she pleases or as the
the device reaches capacity. memory on the device reaches capacity.
Clearly, if an IM Sender loses its sent items state, for example, the Clearly, if an IM Sender loses its sent items state (for example, the
user deletes items from the "Send Items" box, the client may use a user deletes items from the "Sent Items" box), the client may use a
different display strategy in response to apparently unsolicited different display strategy in response to apparently unsolicited
IMDNs. IMDNs.
This specification also does not mandate an IM Sender to run any This specification also does not mandate an IM Sender to run any
timers waiting for an IMDN. There are no time limits associated with timers waiting for an IMDN. There are no time limits regarding when
when IMDNs may be received. IMDNs may be received.
IMDNs may legitimately never be received, so the time between the IMDNs may legitimately never be received, so the time between the
sending of an IM and the generation and ultimate receipt of the IMDN sending of an IM and the generation and ultimate receipt of the IMDN
may simply take a very long time. Some clients may choose to purge may simply take a very long time. Some clients may choose to purge
the state associated with the sent IM. This is the reason for adding the state associated with the sent IM. This is the reason for adding
the time stamp in the IM and having it returned in the IMDN. This the time stamp in the IM and having it returned in the IMDN. This
gives the user some opportunity of remembering what IM was sent. For gives the user some opportunity to remember what IM was sent. For
example if the IMDN indicates that the IM the user sent at 2 p.m. example, if the IMDN indicates that the IM the user sent at 2 p.m.
last Thursday was delivered, the user has a chance of remembering last Thursday was delivered, the user has a chance to remember that
that they sent an IM at 2 p.m. last Thursday. they sent an IM at 2 p.m. last Thursday.
7.1.4. Aggregation of IMDNs 7.1.4. Aggregation of IMDNs
An IM Sender may send an IM to multiple recipients in one Transport An IM Sender may send an IM to multiple recipients in one Transport
Protocol Message (typically using a URI-List server Protocol Message (typically using a URI-List server [RFC5365]) and
[I-D.ietf-sip-uri-list-message]) and request IMDNs. An IM Sender request IMDNs. An IM Sender that requested IMDNs MUST be prepared to
that requested IMDNs MUST be prepared to receive multiple aggregated receive multiple aggregated or non-aggregated IMDNs. See Section 8.3
or non-aggregated IMDNs. See Section 8.3 for details. for details.
7.2. IM Recipient 7.2. IM Recipient
7.2.1. Constructing IMDNs 7.2.1. Constructing IMDNs
IM recipients examine the contents of the Disposition-Notification IM Recipients examine the contents of the Disposition-Notification
header field of the CPIM message to determine if the recipient needs header field of the CPIM message to determine if the recipient needs
to generate an IMDN for that IM. Disposition-Notification header to generate an IMDN for that IM. Disposition-Notification header
fields of CPIM messages can include one or more values. IM fields of CPIM messages can include one or more values. IM
recipients may need to generate zero, one, or more IMDNs for that IM, Recipients may need to generate zero, one, or more IMDNs for that IM,
for example a delivery notification as well as a display for example, a delivery notification as well as a display
notification. In this case, the IM Recipient MUST be able to notification. In this case, the IM Recipient MUST be able to
construct multiple IMDNs per IM. An IM Recipient MUST NOT construct construct multiple IMDNs per IM. An IM Recipient MUST NOT construct
more than one IMDN per disposition type. That is, it must not more than one IMDN per disposition type. That is, it must not
generate a delivery notification indicating "delivered" then followed generate a delivery notification indicating "delivered" followed by a
by a delivery notification indicating "failed" for the same IM. If delivery notification indicating "failed" for the same IM. If the IM
the IM Sender requested only failure notifications and the IM was Sender requested only failure notifications and the IM was
successfully delivered, then no IMDNs will be generated. If the IM successfully delivered, then no IMDNs will be generated. If the IM
recipient does not understand a value of the Disposition-Notification Recipient does not understand a value of the Disposition-Notification
header field, the IM recipient ignores that value. header field, the IM Recipient ignores that value.
The IM Recipient MUST NOT generate "processing" notifications. The IM Recipient MUST NOT generate "processing" notifications.
A Disposition-Notification header field MUST NOT appear in an IMDN A Disposition-Notification header field MUST NOT appear in an IMDN
since it is forbidden to request an IMDN for an IMDN. An IM Sender since it is forbidden to request an IMDN for an IMDN. An IM Sender
MUST ignore a delivery notification request in an IMDN if present. MUST ignore a delivery notification request in an IMDN if present.
The IM Sender MUST NOT send an IMDN for an IMDN. The IM Sender MUST NOT send an IMDN for an IMDN.
An IMDN MUST contain a Message-ID header field. The same rules of An IMDN MUST contain a Message-ID header field. The same rules of
uniqueness for the Message-ID header field that appears in an IM uniqueness for the Message-ID header field that appears in an IM
apply to an IMDN. The Message-ID header field in the IMDN is apply to an IMDN. The Message-ID header field in the IMDN is
different and unrelated to the one in the IM. different and unrelated to the one in the IM.
An IM may contain an IMDN-Record-Route header field (see Section 8 An IM may contain an IMDN-Record-Route header field (see Section 8
for details). If IMDN-Record-Route header fields appear in the IM, for details). If IMDN-Record-Route header fields appear in the IM,
the IM Recipient constructing the IMDN MUST copy the contents of the the IM Recipient constructing the IMDN MUST copy the contents of the
IMDN-Record-Route header fields into IMDN-Route header fields in the IMDN-Record-Route header fields into IMDN-Route header fields in the
IMDN and maintain the order. The IMDN is then sent to the URI in the IMDN and maintain their order. The IMDN is then sent to the URI in
top IMDN-Route header field. IMDN-Record-Route header fields do not the top IMDN-Route header field. IMDN-Record-Route header fields do
make sense in an IMDN and therefore MUST NOT be placed in an IMDN. not make sense in an IMDN and therefore MUST NOT be placed in an
IMDN Recipients MUST ignore it if present. IMDN. IMDN Recipients MUST ignore it if present.
If there is no IMDN-Record-Route header field, the IM Recipient MUST If there is no IMDN-Record-Route header field, the IM Recipient MUST
send the IMDN to the URI in the From header field. send the IMDN to the URI in the From header field.
As stated in CPIM [RFC3862], CPIM messages may need to support MIME As stated in CPIM [RFC3862], CPIM messages may need to support MIME
headers other than Content-type. IM Recipients MUST insert a headers other than Content-type. IM Recipients MUST insert a
Content-Disposition header field, set to the value "notification". Content-Disposition header field set to the value "notification".
This indicates to the IM Sender that the message is an IMDN to an IM This indicates to the IM Sender that the message is an IMDN to an IM
it has earlier sent. it has earlier sent.
7.2.1.1. Constructing Delivery Notifications 7.2.1.1. Constructing Delivery Notifications
The IM Recipient constructs a delivery notification in a similar The IM Recipient constructs a delivery notification in a similar
fashion as an IM, using a CPIM body [RFC3862] that carries a fashion as an IM, using a CPIM body [RFC3862] that carries a
Disposition Notification XML document formatted according to the Disposition Notification XML document formatted according to the
rules specified in Section 11. The MIME type of the Disposition rules specified in Section 11. The MIME type of the Disposition
Notification XML document is "message/imdn+xml". Notification XML document is "message/imdn+xml".
Section 10 defines the schema for an IMDN. Section 10 defines the schema for an IMDN.
An example CPIM body of IMDN looks like the following: The following is an example CPIM body of an IMDN:
From: Bob <im:bob@example.com> From: Bob <im:bob@example.com>
To: Alice <im:alice@example.com> To: Alice <im:alice@example.com>
NS: imdn <urn:ietf:params:imdn> NS: imdn <urn:ietf:params:imdn>
imdn.Message-ID: d834jied93rf imdn.Message-ID: d834jied93rf
Content-type: message/imdn+xml Content-type: message/imdn+xml
Content-Disposition: notification Content-Disposition: notification
Content-length: ... Content-length: ...
<?xml version="1.0" encoding="UTF-8"?> <?xml version="1.0" encoding="UTF-8"?>
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</imdn> </imdn>
7.2.1.2. Constructing Display Notifications 7.2.1.2. Constructing Display Notifications
The IM Recipient constructs a display notification in a similar The IM Recipient constructs a display notification in a similar
fashion as the delivery notification. See Section 7.2.1.1 for fashion as the delivery notification. See Section 7.2.1.1 for
details. details.
Section 10 defines the schema for an IMDN. Section 10 defines the schema for an IMDN.
An example looks like the following: The following is an example:
From: Bob <im:bob@example.com> From: Bob <im:bob@example.com>
To: Alice <im:alice@example.com> To: Alice <im:alice@example.com>
NS: imdn <urn:ietf:params:imdn> NS: imdn <urn:ietf:params:imdn>
imdn.Message-ID: dfjkleriou432333 imdn.Message-ID: dfjkleriou432333
Content-type: message/imdn+xml Content-type: message/imdn+xml
Content-Disposition: notification Content-Disposition: notification
Content-length: ... Content-length: ...
<?xml version="1.0" encoding="UTF-8"?> <?xml version="1.0" encoding="UTF-8"?>
skipping to change at page 15, line 31 skipping to change at page 15, line 31
<status> <status>
<displayed/> <displayed/>
</status> </status>
</display-notification> </display-notification>
</imdn> </imdn>
There are situations where the IM Recipient cannot determine if or There are situations where the IM Recipient cannot determine if or
when the IM has been displayed. The IM Recipient in this case when the IM has been displayed. The IM Recipient in this case
generates a display notification with a <status> value of "error" to generates a display notification with a <status> value of "error" to
indicate an internal error by the server. Note that the IM Recipient indicate an internal error by the server. Note that the IM Recipient
may choose to ignore any IMDN requests and not to send any IMDNs. An may choose to ignore any IMDN requests and not send any IMDNs. An IM
IM recipient may not wish to let a sender know if a particular Recipient may not wish to let a sender know whether or not a
message has been displayed to her or not. This could be on a per- particular message has been displayed to her. This could be a per-
message, per-sender, or programmed policy choice. message, per-sender, or programmed policy choice.
8. Intermediary Behaviour 8. Intermediary Behaviour
In this context, intermediaries are application servers (including In this context, intermediaries are application servers (including
URI-List servers and Store-and-Forward server) and gateways. A URI-List and store-and-forward servers) and gateways. A gateway is a
gateway is a server that translates between different IM systems that server that translates between different IM systems that use
use different protocols. different protocols.
A URI-List server may change the IM Recipient address from its own to A URI-List server may change the IM Recipient address from its own to
the address of the final recipient of that IM for every copy it makes the address of the final recipient of that IM for every copy it makes
that it sends to the list members (see that it sends to the list members (see [RFC5365] for details). In
[I-D.ietf-sip-uri-list-message] for details). In this case, if the this case, if the IM Sender is requesting an IMDN, the intermediary
IM Sender is requesting an IMDN, the intermediary SHOULD add an SHOULD add an Original-To header field to the IM, populating it with
Original-To header field to the IM populating it with the address the address that was in the CPIM To header field before it was
that was in the CPIM To header field before it was changed. That is, changed. That is, the intermediary populates the Original-To header
the intermediary populates the Original-To header field with the field with the intermediary address. Of course, one may configure an
intermediary address. Of course, one may configure an intermediary intermediary to restrict it from rewriting or populating the
to restrict it from rewriting or populating the Original-To field. Original-To field. An intermediary MUST NOT add an Original-To
An intermediary MUST NOT add an Original-To header field if one header field if one already exists. An intermediary MAY have an
already exists. An intermediary MAY have an administrative administrative configuration to not reveal the original Request-URI,
configuration to not reveal the original Request-URI, and as such, and as such, MUST NOT add an Original-To header.
MUST NOT add an Original-To header.
An IM reply for a page-mode IM is not linked in any way to the An IM reply for a page-mode IM is not linked in any way to the
initial IM and can end up at a diffent user agent from where the initial IM and can end up at a different user agent from where the
initial IM originated, depending on how the recipient URI gets initial IM originated, depending on how the recipient URI gets
resolved. Therefore, IM replies may traverse different resolved. Therefore, IM replies may traverse different
intermediaries. An IMDN, on the other hand, needs to traverse the intermediaries. An IMDN, on the other hand, needs to traverse the
same intermediares as the IM itself since those intermediares may be same intermediaries as the IM itself since those intermediaries may
required to report negative delivery notifications if the IM was not be required to report negative delivery notifications if the IM was
delivered successfully. Some of those interdemiaries are, for not delivered successfully. Some of those intermediaries are, for
example, store-and-forward servers that may report that an IM has example, store-and-forward servers that may report that an IM has
been processed and later report that the IM has failed to be been processed and later report that the IM has failed to be
delivered. delivered.
For the reasons stated above, an intermediary MAY choose to remain on For the reasons stated above, an intermediary MAY choose to remain on
the path of IMDNs for a specific IM. It can do so by adding a CPIM the path of IMDNs for a specific IM. It can do so by adding a CPIM
IMDN-Record-Route header field as the top IMDN-Record-Route header IMDN-Record-Route header field as the top IMDN-Record-Route header
field. The value of this field MUST be the intermediary's own field. The value of this field MUST be the intermediary's own
address. An intermediary that does not support this extension will address. An intermediary that does not support this extension will
obviously not add the IMDN-Record-Route header field. This allows obviously not add the IMDN-Record-Route header field. This allows
IMDNs to traverse directly from the IM Recipient to the IM Sender IMDNs to traverse directly from the IM Recipient to the IM Sender
even if the IM traversed an intermediary not supporting this even if the IM traversed an intermediary not supporting this
extension. extension.
An intermediary receiving an IMDN checks the top IMDN-Route header An intermediary receiving an IMDN checks the top IMDN-Route header
field. If that header field carries the intermediary address, the field. If that header field carries the intermediary address, the
intermediary removes that value and forwards the IMDN to the address intermediary removes that value and forwards the IMDN to the address
indicated in the now top IMDN-Route header field. If no additional indicated in the new top IMDN-Route header field. If no additional
IMDN-Route header fields are present, the IMDN is forwarded to the IMDN-Route header fields are present, the IMDN is forwarded to the
address in the CPIM To header field. address in the CPIM To header field.
An intermediary MUST remove any information about the final An intermediary MUST remove any information about the final
recipients of a list if the list membership is not disclosed. The recipients of a list if the list membership is not disclosed. The
intermediary does that by removing the <recipient-uri> element and/or intermediary does that by removing the <recipient-uri> element and/or
<original-recipient-uri> element from the body of the IMDN before <original-recipient-uri> element from the body of the IMDN before
forwarding it to the IM Sender. forwarding it to the IM Sender.
8.1. Constructing Processing Notifications 8.1. Constructing Processing Notifications
Intermediaries are the only entities that construct processing Intermediaries are the only entities that construct processing
notifications. They do so only if the IM Sender has requested a notifications. They do so only if the IM Sender has requested a
"processing" notification by including a Disposition-Notification "processing" notification by including a Disposition-Notification
header field with value "processing". header field with value "processing".
The intermediary can create and send "processing" notifications The intermediary can create and send "processing" notifications
indicating that an IM has been processed or stored. The intermediary indicating that an IM has been processed or stored. The intermediary
MUST NOT send more than one IMDN for the same disposition type. MUST NOT send more than one IMDN for the same disposition type --
I.e., it must not send a "processing" notification indicating that an i.e., it must not send a "processing" notification indicating that an
IM is being "processed" followed by another IMDN indicating that the IM is being "processed" followed by another IMDN indicating that the
same IM is "stored". same IM is "stored".
An intermediary constructs a "processing" notification in a similar An intermediary constructs a "processing" notification in a similar
fashion as the delivery notification. See Section 7.2.1.1 for fashion as the IM Recipient constructs a delivery notification. See
details. Section 7.2.1.1 for details.
An example looks like the following: The following is an example:
Content-type: Message/CPIM Content-type: Message/CPIM
From: Bob <im:bob@example.com> From: Bob <im:bob@example.com>
To: Alice <im:alice@example.com> To: Alice <im:alice@example.com>
Content-type: message/imdn+xml Content-type: message/imdn+xml
Content-Disposition: notification Content-Disposition: notification
Content-length: ... Content-length: ...
<?xml version="1.0" encoding="UTF-8"?> <?xml version="1.0" encoding="UTF-8"?>
skipping to change at page 18, line 5 skipping to change at page 17, line 51
8.2. Constructing Delivery Notifications 8.2. Constructing Delivery Notifications
Intermediaries MAY construct negative delivery notifications. They Intermediaries MAY construct negative delivery notifications. They
do so only if the IM Sender has requested a "negative-delivery" do so only if the IM Sender has requested a "negative-delivery"
notification by including a Disposition-Notification header field notification by including a Disposition-Notification header field
with value "negative-delivery" AND an error was returned for that IM. with value "negative-delivery" AND an error was returned for that IM.
The intermediary can create and send "negative-delivery" The intermediary can create and send "negative-delivery"
notifications indicating that an IM has failed to be delivered. The notifications indicating that an IM has failed to be delivered. The
intermediary MUST NOT send more than one IMDN for the same intermediary MUST NOT send more than one IMDN for the same
disposition type. I.e., it must not send a "failed" notification disposition type -- i.e., it must not send a "failed" notification
indicating that an IM has failed followed by another IMDN indicating indicating that an IM has failed followed by another IMDN indicating
that an IMDN is "forbidden". that an IMDN is "forbidden".
An intermediary constructs a "negative-delivery" notification much An intermediary constructs a "negative-delivery" notification much
like the IM Recipient. See Section 7.2.1.1 for details. like the IM Recipient. See Section 7.2.1.1 for details.
8.3. Aggregation of IMDNs 8.3. Aggregation of IMDNs
As previously described, URI-List servers are intermediaries. As previously described, URI-List servers are intermediaries.
A URI-List server may choose to aggregate IMDNs using local policy A URI-List server may choose (using local policy) to aggregate IMDNs
for making such a decision or it may send individual IMDNs instead. or it may send individual IMDNs instead. When a URI-List server
When a URI-List server receives an IM and decides to aggregate IMDNs, receives an IM and decides to aggregate IMDNs, it can wait for a
it can wait for a configurable period of time or until all recipients configurable period of time or until all recipients have sent the
have sent the IMDN, whichever comes first, before the URI-List server IMDN, whichever comes first, before it sends an aggregated IMDN.
sends an aggregated IMDN. Note that some IMDNs, for example Note that some IMDNs, for example "displayed" notifications, may
"displayed" notifications, may never come due to user settings. It never come due to user settings. How long to wait before sending an
is an administrator configuration and an implementation issue how aggregated IMDN and before a URI-List server removes state for that
long to wait before sending an aggregated IMDN and before a URI-List IM is an administrator configuration and implementation issue.
server removes state for that IM.
A URI-List server MAY choose to send multiple aggregated IMDNs. A A URI-List server MAY choose to send multiple aggregated IMDNs. A
timer can be started and when it fires, the URI-List server can timer can be started, and when it fires, the URI-List server can
aggregate whatever IMDNs it has so far for that IM, send the aggregate whatever IMDNs it has so far for that IM, send the
aggregated IMDN and restart the timer for the next batch. This is aggregated IMDN, and restart the timer for the next batch. This is
needed for scenarios where the IM Sender has requested more than one needed for scenarios where the IM Sender has requested more than one
IMDN for a specific IM, for example, delivery notifications as well IMDN for a specific IM -- for example, delivery notifications as well
as display notifications, or when the URI-List server is short on as display notifications -- or when the URI-List server is short on
resources and chooses to prioritise forwarding IMs over IMDNs. resources and chooses to prioritise forwarding IMs over IMDNs.
A second timer can be running and when it fires, the state of the IM A second timer can be running, and when it fires, the state of the IM
is deleted. In this case, the URI-List server consumes any IMDNs is deleted. In this case, the URI-List server consumes any IMDNs
that might arrive after that time. that might arrive after that time.
Please note the references to timers in the above paragraphs are not Please note the references to timers in the above paragraphs are not
normative and are only present to help describe one way one might normative and are only present to help describe one way one might
implement aggregation. implement aggregation.
A URI-List server MAY aggregate IMDNs for the case where the list A URI-List server MAY aggregate IMDNs for the case where the list
membership information is not disclosed. There may be scenarios membership information is not disclosed. There may be scenarios
where the URI-List server starts sending aggregated IMDNs and switch where the URI-List server starts sending aggregated IMDNs and
to individual ones or visa versa. A timer firing so often may in switches to individual ones or visa versa. A timer firing often may
fact have that effect. in fact have that effect.
The aggregated IMDN is constructed using the multipart/mixed MIME The aggregated IMDN is constructed using the multipart/mixed MIME
type and including all the received IMDNs as message/imdn+xml as type and including as individual payloads all the IMDNS that were
individual payloads. received as message/imdn+xml.
Below is an example of aggregated IMDNs. Below is an example of aggregated IMDNs.
From: Bob <im:bob@example.com> From: Bob <im:bob@example.com>
To: Alice <im:alice@example.com> To: Alice <im:alice@example.com>
NS: imdn <urn:ietf:params:imdn> NS: imdn <urn:ietf:params:imdn>
imdn.Message-ID: d834jied93rf imdn.Message-ID: d834jied93rf
Content-type: multipart/mixed; Content-type: multipart/mixed;
boundary="imdn-boundary" boundary="imdn-boundary"
Content-Disposition: notification Content-Disposition: notification
skipping to change at page 20, line 9 skipping to change at page 20, line 9
</status> </status>
</display-notification> </display-notification>
</imdn> </imdn>
--imdn-boundary --imdn-boundary
9. Identifying Messages 9. Identifying Messages
Messages are typically carried in a transport protocol like SIP Messages are typically carried in a transport protocol like SIP
[RFC3261]. If the payload carried by the transport protocol does not [RFC3261]. If the payload carried by the transport protocol does not
contain any parts of type Message/CPIM then the message is an IM. If contain any parts of type Message/CPIM, then the message is an IM.
the payload contains any parts of type Message/CPIM, and none of If the payload contains any parts of type Message/CPIM, and none of
those parts contains a payload that is of type "message/imdn+xml", those parts contains a payload that is of type "message/imdn+xml",
the message is an IM. It is not valid to attempt to carry both an IM the message is an IM. It is not valid to attempt to carry both an IM
and an IMDN in a multipart payload in a single transport protocol and an IMDN in a multipart payload in a single transport protocol
message. message.
A message is identified as a delivery notification by examining its A message is identified as a delivery notification by examining its
contents. The message is a delivery notification if the Content-type contents. The message is a delivery notification if the Content-type
header field present has a value of "message/imdn+xml", the Content- header field present has a value of "message/imdn+xml", the Content-
Disposition header field has a value of "notification", and the Disposition header field has a value of "notification", and the
<delivery-notification> element appears in that xml body. <delivery-notification> element appears in that XML body.
A message is identified as a processing notification or display A message is identified as a processing notification or display
notification in a similar fashion as a delivery notification. The notification in a similar fashion as a delivery notification. The
difference is that for a processing notification, the <processing- difference is that, for a processing notification, the <processing-
notification> element appears in the xml body. For a display notification> element appears in the XML body. For a display
notification, the <display-notification> element appears in the xml notification, the <display-notification> element appears in the XML
body. body.
10. Header Fields Formal Syntax 10. Header Fields Formal Syntax
The following syntax specification uses the message header field The following syntax specification uses the message header field
syntax as described in Section 3 of RFC 3862 [RFC3862]. syntax as described in Section 3 of RFC 3862 [RFC3862].
Header field syntax is described without a name space qualification. Header field syntax is described without a name space qualification.
Following the rules in RFC 3862 [RFC3862], header field names and Following the rules in RFC 3862 [RFC3862], header field names and
other text are case sensitive and MUST be used as given, using other text are case sensitive and MUST be used as given, using
exactly the indicated upper case and lower case letters. exactly the indicated upper-case and lower-case letters.
Disposition-Notification = Disposition-Notification =
"Disposition-Notification" ": " "Disposition-Notification" ": "
[(notify-req *(COMMA notify-req))] [(notify-req *(COMMA notify-req))]
notify-req = notify-req =
("negative-delivery" / "positive-delivery" / ("negative-delivery" / "positive-delivery" /
"processing" / "display" / Token) *(SEMI disp-notify-params) "processing" / "display" / Token) *(SEMI disp-notify-params)
disp-notify-params = Ext-param disp-notify-params = Ext-param
skipping to change at page 21, line 30 skipping to change at page 21, line 30
"IMDN-Record-Route" ": " [ Formal-name ] "<" URI ">" "IMDN-Record-Route" ": " [ Formal-name ] "<" URI ">"
IMDN-Route = "IMDN-Route" ": " [ Formal-name ] "<" URI ">" IMDN-Route = "IMDN-Route" ": " [ Formal-name ] "<" URI ">"
SEMI = *SP ";" *SP ; semicolon SEMI = *SP ";" *SP ; semicolon
COMMA = *SP "," *SP ; comma COMMA = *SP "," *SP ; comma
11. IMDN Format 11. IMDN Format
11.1. Structure of XML-Encoded IMDN Payload 11.1. Structure of an XML-Encoded IMDN Payload
An IMDN Payload is an XML document [XML] that MUST be well formed and An IMDN payload is an XML document [XML] that MUST be well-formed and
MUST be valid according to schemas, including extension schemas, MUST be valid according to schemas, including extension schemas,
available to the validater and applicable to the XML document. The available to the validater and applicable to the XML document. The
IMDN Payload MUST be based on XML 1.0 and MUST be encoded using IMDN payload MUST be based on XML 1.0 and MUST be encoded using
UTF-8. UTF-8.
The schema allows qualified extension elements in several positions The schema allows qualified extension elements in several positions
other than the "urn:ietf:params:xml:ns:imdn" namespace. To maintain other than the "urn:ietf:params:xml:ns:imdn" namespace. To maintain
forwards compatibility (newer instance documents can be used by forwards compatibility (i.e., newer instance documents can be used by
existing consumers) the new specifications MUST NOT extend the existing consumers), the new specifications MUST NOT extend the
allowable content of this specification. The backwards compatibility allowable content of this specification. The backwards compatibility
(existing instance documents can also be used by updated new (i.e., existing instance documents can also be used by updated, new
consumers) MAY break if there are conflicts with the existing consumers) MAY break if there are conflicts with the existing
qualified names of extension elements and possible new qualified names of extension elements and possible future
specifications. The IETF MAY specify new extension elements within specifications. The IETF MAY specify new extension elements within
the "sub-namespace" of "urn:ietf:params:xml:ns:" for this message/ the "sub-namespace" of "urn:ietf:params:xml:ns:" for this message/
imdn+xml MIME type. imdn+xml MIME type.
Possible future specifications can add new element definitions with Possible future specifications can add new element definitions with
the combine="interleave" pattern. When multiple elements of this new the combine="interleave" pattern. When multiple elements of this new
type are then allowed, the new definition MUST contain the type are then allowed, the new definition MUST contain the
<zeroOrMore> cardinality rule. If the new specification does allow <zeroOrMore> cardinality rule. If the new specification does allow
only a single new element, the <optional> cardinality rule MUST be only a single new element, the <optional> cardinality rule MUST be
used. These cardinality requirements maintain the backwards used. These cardinality requirements maintain the backwards
compatibility of existing instance documents with newer consumers. compatibility of existing instance documents with newer consumers.
Also the new specification MUST then re-define either the "anyIMDN" Also, the new specification MUST then redefine either the "anyIMDN"
extension, or the individual extension points which reference it, so extension or the individual extension points that reference it, so
that new element definitions do not match with this redefined, and that new element definitions do not match with this redefined and
more limited wildcard pattern. more limited wildcard pattern.
The name space identifier for elements defined by this specification The name space identifier for elements defined by this specification
is a URN [URN], using the name space identifier 'ietf' defined by is a URN [URN], using the name space identifier 'ietf' defined by
[URN_NS] and extended by [IANA]. This urn is: [URN_NS] and extended by [IANA]. This urn is:
urn:ietf:params:xml:ns:imdn. urn:ietf:params:xml:ns:imdn.
This name space declaration indicates the name space on which the This namespace declaration indicates the namespace on which the IMDN
IMDN is based. is based.
The root element is <imdn>. The <imdn> element has sub-elements, The root element is <imdn>. The <imdn> element has sub-elements,
namely <message-id>, <datetime>, <recipient-uri>, <original- namely <message-id>, <datetime>, <recipient-uri>, <original-
recipient-uri>, <subject>, and one of <delivery-notification>, recipient-uri>, <subject>, and one of <delivery-notification>,
<processing-notification> or <display-notification>. A <status> also <processing-notification>, or <display-notification>. A <status>
appears as a sub-element of <delivery-notification>, <processing- also appears as a sub-element of <delivery-notification>,
notification> and <display-notification>. The elements are described <processing-notification>, and <display-notification>. The elements
in details in the following sections. are described in detail in the following sections.
<imdn>, can be extended in the future to include new disposition <imdn> can be extended in the future to include new disposition
notification types or other elements, as described in Section 11.1.9. notification types or other elements, as described in Section 11.1.9.
11.1.1. The <message-id> Element 11.1.1. The <message-id> Element
The <message-id> element is mandatory according to the XML schema and The <message-id> element is mandatory according to the XML schema and
carries the message id that appeared in the Message-ID header field carries the message ID that appeared in the Message-ID header field
of the IM. of the IM.
11.1.2. The <datetime> Element 11.1.2. The <datetime> Element
The <datetime> element is mandatory and carries the date and time the The <datetime> element is mandatory and carries the date and time the
IM was sent (not the IMDN). This information is obtained from the IM was sent (not the IMDN). This information is obtained from the
DateTime header field of the IM. DateTime header field of the IM.
11.1.3. The <recipient-uri> Element 11.1.3. The <recipient-uri> Element
skipping to change at page 23, line 14 skipping to change at page 23, line 14
11.1.4. The <original-recipient-uri> Element 11.1.4. The <original-recipient-uri> Element
The <original-recipient-uri> element is optional and carries the URI The <original-recipient-uri> element is optional and carries the URI
of the original recipient. It MUST be present if the IM carried the of the original recipient. It MUST be present if the IM carried the
Original-To header field. This information is obtained from the Original-To header field. This information is obtained from the
Original-To header field of the IM. Original-To header field of the IM.
11.1.5. The <subject> Element 11.1.5. The <subject> Element
The <subject> element is optional. If present it MUST cary the text The <subject> element is optional. If present, it MUST carry the
and, if present, language attribute, that was in the Subject header text and language attributes that were in the Subject header field,
field, if any. This allows for a human level correlation between an if any. This allows for a human-level correlation between an IM and
IM and an IMDN. If there are more than one Subject header fields in an IMDN. If there are more than one Subject header fields in an IM,
an IM, selecting any one of them to place in the IMDN payload selecting any one of them to place in the IMDN payload <subject>
<subject> element will suffice. The sender then needs to compare element will suffice. The sender then needs to compare Subject
Subject header fields until a match or not match is determined. header fields until a match or not match is determined.
11.1.6. The <delivery-notification>, <processing-notification> and 11.1.6. The <delivery-notification>, <processing-notification>, and
<display-notification> Elements <display-notification> Elements
The appearance of one of the <delivery-notification>, <processing- The appearance of one of the <delivery-notification>, <processing-
notification> and <display-notification> elements is mandatory and notification>, and <display-notification> elements is mandatory and
carries the disposition type that the IM Sender requested and is carries the disposition type that the IM Sender requested and is
being reported. It carries the sub-element <status>. being reported. It carries the sub-element <status>.
11.1.7. The <status> Element 11.1.7. The <status> Element
The <status> element is mandatory and carries the result of the The <status> element is mandatory and carries the result of the
disposition request. For notification type <delivery-notification>, disposition request. For notification type <delivery-notification>,
it can carry one of the sub-elements <delivered>, <failed>, it can carry one of the sub-elements <delivered>, <failed>,
<forbidden> or <error>. For notification type <display- <forbidden>, or <error>. For notification type <display-
notification>, it can carry one of the sub-elements <displayed>, notification>, it can carry one of the sub-elements <displayed>,
<forbidden> or <error>. For notification type <processing- <forbidden>, or <error>. For notification type <processing-
notification>, it can carry one of the sub-elements <processed>, notification>, it can carry one of the sub-elements <processed>,
<stored>, <forbidden> or <error>. <forbidden> means the disposition <stored>, <forbidden>, or <error>. <forbidden> means the disposition
was denied. <error> means internal server error. It can also be was denied. <error> means internal server error. The <status>
extended to carry any other status extension. element can also be extended to carry any other status extension.
11.1.8. MIME Type for IMDN Payload 11.1.8. MIME Type for IMDN Payload
The MIME type for the IMDN Payload is "message/imdn+xml". The IMDN The MIME type for the IMDN payload is "message/imdn+xml". The IMDN
MUST identify the payload as MIME type "message/imdn+xml" in the MUST identify the payload as MIME type "message/imdn+xml" in the
Content-type header field. Content-type header field.
11.1.9. The RelaxNG Schema 11.1.9. The RelaxNG Schema
<?xml version="1.0" encoding="UTF-8"?> <?xml version="1.0" encoding="UTF-8"?>
<grammar <grammar
xmlns="http://relaxng.org/ns/structure/1.0" xmlns="http://relaxng.org/ns/structure/1.0"
xmlns:a="http://relaxng.org/ns/compatibility/annotations/1.0" xmlns:a="http://relaxng.org/ns/compatibility/annotations/1.0"
datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes" datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes"
skipping to change at page 26, line 5 skipping to change at page 26, line 5
<empty/> <empty/>
</element> </element>
<element name="error"> <element name="error">
<empty/> <empty/>
</element> </element>
</choice> </choice>
</define> </define>
<!-- <imdn> extension point for the extension schemas to add <!-- <imdn> extension point for the extension schemas to add
new definitions with the combine="interleave" pattern. new definitions with the combine="interleave" pattern.
Extension schemas should add proper cardinalities, Extension schemas should add proper cardinalities. For
i.e. <zeroOrMore> enclosed e.g. with the new element example, the <zeroOrMore> cardinality should be used if
if multiple new elements are allowed, and <optional> the extension is to allow multiple elements, and the
if a single new element is allowed --> <optional> cardinality should be used if the extension
is to allow a single optional element. -->
<define name="imdnExtension"> <define name="imdnExtension">
<zeroOrMore> <zeroOrMore>
<ref name="anyIMDN"/> <ref name="anyIMDN"/>
</zeroOrMore> </zeroOrMore>
</define> </define>
<!-- delivery-notification <status> extension point --> <!-- delivery-notification <status> extension point -->
<define name="deliveryExtension"> <define name="deliveryExtension">
<zeroOrMore> <zeroOrMore>
<ref name="anyIMDN"/> <ref name="anyIMDN"/>
skipping to change at page 26, line 39 skipping to change at page 26, line 41
<!-- processing-notification <status> extension point --> <!-- processing-notification <status> extension point -->
<define name="processingExtension"> <define name="processingExtension">
<zeroOrMore> <zeroOrMore>
<ref name="anyIMDN"/> <ref name="anyIMDN"/>
</zeroOrMore> </zeroOrMore>
</define> </define>
<!-- wildcard definition for complex elements (of mixed type) <!-- wildcard definition for complex elements (of mixed type)
unqualified or qualified in the imdn namespace. unqualified or qualified in the imdn namespace.
Extension schemas MUST redefine this or the Extension schemas MUST redefine this or the
individual previous definitions which use this definition. individual, previous definitions that use this definition.
In other words, the extension schema MUST reduce the In other words, the extension schema MUST reduce the
allowable content in order to maintain deterministic allowable content in order to maintain deterministic
and unambiquous schemas with the interleave pattern. --> and unambiguous schemas with the interleave pattern. -->
<define name="anyIMDN"> <define name="anyIMDN">
<element> <element>
<anyName> <anyName>
<except> <except>
<nsName ns="urn:ietf:params:xml:ns:imdn"/> <nsName ns="urn:ietf:params:xml:ns:imdn"/>
<nsName ns=""/> <nsName ns=""/>
</except> </except>
</anyName> </anyName>
<ref name="anyExtension"/> <ref name="anyExtension"/>
</element> </element>
skipping to change at page 27, line 38 skipping to change at page 27, line 40
</attribute> </attribute>
<text/> <text/>
<ref name="any"/> <ref name="any"/>
</choice> </choice>
</zeroOrMore> </zeroOrMore>
</element> </element>
</define> </define>
</grammar> </grammar>
12. Transporting Messages using SIP 12. Transporting Messages Using SIP
12.1. Endpoint Behaviour 12.1. Endpoint Behaviour
12.1.1. Sending Requests 12.1.1. Sending Requests
The IM Sender constructs a SIP MESSAGE request using RFC 3428 The IM Sender constructs a SIP MESSAGE request using RFC 3428
[RFC3428]. The Content-type header field indicates the MIME type of [RFC3428]. The Content-type header field indicates the MIME type of
the request payload. When using this extension, the Content-type the request payload. When using this extension, the Content-type
header field MUST be of MIME type "message/cpim" [RFC3862] for both header field MUST be of MIME type "message/cpim" [RFC3862] for both
IMs and IMDNs. The IM Sender constructs the payload according to IMs and IMDNs. The IM Sender constructs the payload according to
Section 7. Section 7.
The IM Sender constructs a SIP MESSAGE request to multiple recipients The IM Sender constructs a SIP MESSAGE request to multiple recipients
in a similar manner as a SIP MESSAGE request to a single recipient. in a similar manner as a SIP MESSAGE request to a single recipient.
Multiple-Recipient MESSAGE Requests in SIP "Multiple-Recipient MESSAGE Requests in SIP" [RFC5365] describes the
[I-D.ietf-sip-uri-list-message] describes the differences. differences.
IM senders can remain anonymous. For example, the sender can set the IM Senders can remain anonymous. For example, the sender can set the
SIP From header field of the SIP message to an anonymous URI. As SIP From header field of the SIP message to an anonymous URI. As
there is no return address, anonymous IM senders SHOULD NOT request there is no return address, anonymous IM Senders SHOULD NOT request
disposition notifications. An IM Recipient MAY ignore such request disposition notifications. An IM Recipient MAY ignore such a request
if the IM Sender is anonymous. if the IM Sender is anonymous.
12.1.2. Sending Responses 12.1.2. Sending Responses
An endpoint receiving a SIP MESSAGE request constructs a SIP response An endpoint receiving a SIP MESSAGE request constructs a SIP response
according to RFC 3428 [RFC3428]. Of course, an endpoint will send a according to RFC 3428 [RFC3428]. Of course, an endpoint will send a
SIP response to the MESSAGE request regardless of the type of message SIP response to the MESSAGE request regardless of the type of message
(IM or IMDN) is has received, or the disposition type it has been (IM or IMDN) it has received or the disposition type for which it has
asked for. been asked.
12.1.3. Receiving Requests 12.1.3. Receiving Requests
12.1.3.1. Instant Message 12.1.3.1. Instant Message
A SIP MESSAGE request is identified as an IM by examining its A SIP MESSAGE request is identified as an IM by examining its
contents according to Section 9. contents according to Section 9.
If an IM Recipient received a SIP MESSAGE request that is an IM that If an IM Recipient received a SIP MESSAGE request that is an IM
requested a positive-delivery notification, and that IM Recipient has requesting a positive-delivery notification, and that IM Recipient
constructed and sent a SIP 2xx class response, it MAY generate a has constructed and sent a SIP 2xx class response, it MAY generate a
positive-delivery notification after making sure that the IM has been positive-delivery notification after making sure that the IM has been
delivered to the user or application. A gateway, for example, can delivered to the user or application. A gateway, for example, can
generate a 2xx response before the final recipient received the IM. generate a 2xx response before the final recipient received the IM.
The IM Recipient constructs a positive-delivery notification The IM Recipient constructs a positive-delivery notification
according to Section 7.2.1.1. The IM Recipient places the message as according to Section 7.2.1.1. The IM Recipient places the message as
the payload in a SIP MESSAGE request. the payload in a SIP MESSAGE request.
If an IM Recipient received a SIP MESSAGE request that is an IM that If an IM Recipient received a SIP MESSAGE request that is an IM
requested a negative-delivery, and that IM Recipient has constructed requesting a negative-delivery, and that IM Recipient has constructed
and sent a 2xx class response, it SHOULD generate a negative-delivery and sent a 2xx class response, it SHOULD generate a negative-delivery
notification if it learnt that the final recipient or application did notification if it learnt that the final recipient or application did
not receive the IM (a gateway, for example, can generate a 2xx not receive the IM (a gateway, for example, can generate a 2xx
response before it has an error response from downstream or before response before it has an error response from downstream or before
any internal timers fire waiting for a response). The negative- any internal timers fire waiting for a response). The negative-
delivery notification is constructed according to Section 7.2.1.1. delivery notification is constructed according to Section 7.2.1.1.
The message is then placed as the payload in a SIP MESSAGE request. The message is then placed as the payload in a SIP MESSAGE request.
If an IM Recipient received a SIP MESSAGE request that is an IM that If an IM Recipient received a SIP MESSAGE request that is an IM
requested a negative-delivery notification, and the IM Recipient has requesting a negative-delivery notification, and the IM Recipient has
constructed and sent an non-2xx final response, it MUST NOT generate constructed and sent a non-2xx final response, it MUST NOT generate a
a negative-delivery notification. negative-delivery notification.
If an IM Recipient received a SIP MESSAGE request that is an IM that If an IM Recipient received a SIP MESSAGE request that is an IM
requested a display notification, and that IM Recipient has requesting a display notification, and that IM Recipient has
constructed and sent a SIP 2xx class response, it MAY generate a constructed and sent a SIP 2xx class response, it MAY generate a
display notification after making sure that the IM has been presented display notification after making sure that the IM has been presented
to the user or application. It is outside the scope of this document to the user or application. It is outside the scope of this document
how a determination can be made whether the IM has been read. Note to discuss how a determination can be made whether the IM has been
that the option to send a display notification or not can be left to read. Note that the decision whether or not to send a display
the user. An application may allow a user to configure such choice. notification can be left to the user. An application may allow a
The IM Recipient constructs the display notification according to user to configure such a choice. The IM Recipient constructs the
Section 7.2.1.2. The IM Recipient places the message as the payload display notification according to Section 7.2.1.2. The IM Recipient
in a SIP MESSAGE request. places the message as the payload in a SIP MESSAGE request.
For IMDNs, the IM Recipient populates the SIP Request-URI and the SIP For IMDNs, the IM Recipient populates the SIP Request-URI and the SIP
To header field using the address that appeared in the SIP From To header field using the address that appeared in the SIP From
header field in the IM. header field in the IM.
12.1.3.2. Delivery Notification 12.1.3.2. Delivery Notification
A SIP MESSAGE request is identified as delivery notification by A SIP MESSAGE request is identified as a delivery notification by
examining its contents according to Section 9. examining its contents according to Section 9.
12.1.3.3. Display Notification 12.1.3.3. Display Notification
A SIP MESSAGE request is identified as display notification by A SIP MESSAGE request is identified as a display notification by
examining its contents according to Section 9. examining its contents according to Section 9.
12.2. Intermediary Behaviour 12.2. Intermediary Behaviour
In this context, intermediaries include application servers, In this context, intermediaries include application servers
including URI-List servers, Store-and-Forward servers, and gateways. (including URI-List and store-and-forward servers) and gateways. SIP
SIP Proxies MUST NOT generate IMDNs but MUST forward them like any Proxies MUST NOT generate IMDNs but MUST forward them like any other
other SIP request. SIP request.
Intermediaries forward a SIP MESSAGE request to multiple recipients Intermediaries forward a SIP MESSAGE request to multiple recipients
according to [I-D.ietf-sip-uri-list-message]. according to [RFC5365].
If an intermediary receives an IM, the intermediary examines the If an intermediary receives an IM, the intermediary examines the
body. If the body is of type "message/cpim" the intermediary then body. If the body is of type "message/cpim", the intermediary then
looks for a Disposition-Notification CPIM header field in the looks for a Disposition-Notification CPIM header field in the
message. If the Disposition-Notification CPIM header field has message. If the Disposition-Notification CPIM header field has
either the value "positive-delivery" or "negative-delivery", and, in either the value "positive-delivery" or "negative-delivery", and, in
processing the IM, the intermediary generates a SIP 2xx class processing the IM, the intermediary generates a SIP 2xx class
response to the MESSAGE request, then the intermediary performs the response to the MESSAGE request, then the intermediary performs the
following actions. following actions.
If the Disposition-Notification header field contains a value of If the Disposition-Notification header field contains a value of
"positive-delivery", the intermediary MUST NOT generate a delivery "positive-delivery", the intermediary MUST NOT generate a delivery
notification if it receives a SIP 2xx class response for the sent IM. notification if it receives a SIP 2xx class response for the sent IM.
Just because a downstream entity received a MESSAGE request does not Just because a downstream entity received a MESSAGE request does not
mean the message was relayed to its ultimate destination or was mean the message was relayed to its ultimate destination or was
delivered. Thus, the intermediary cannot say delivery occurred just delivered. Thus, the intermediary cannot say delivery occurred just
because it received a 2xx response. because it received a 2xx response.
If the Disposition-Notification header field contains a value of If the Disposition-Notification header field contains a value of
"negative-delivery", the intermediary SHOULD generate a delivery "negative-delivery", the intermediary SHOULD generate a delivery
notification if it receives a SIP 4xx, 5xx or 6xx class final notification if it receives a SIP 4xx, 5xx, or 6xx class final
response for the sent IM. If it has received a SIP 2xx class response for the sent IM. If it has received a SIP 2xx class
response followed by a negative-delivery notification, the response followed by a negative-delivery notification, the
intermediary forwards that negative-delivery notification or intermediary forwards that negative-delivery notification or
aggregates it. aggregates it.
If the Disposition-Notification header field contains a value of If the Disposition-Notification header field contains a value of
"processing", the intermediary MAY generate a processing notification "processing", the intermediary MAY generate a processing notification
after it has forwarded or stored the IM. The rest of the procedures after it has forwarded or stored the IM. The rest of the procedures
in Section 8.1 apply. in Section 8.1 apply.
The procedure for generating such IMDN is the same as that of an IM The procedure for generating such an IMDN is the same as that of an
Recipient (Section 7.2.1.1). IM Recipient (Section 7.2.1.1).
The <recipient-uri> element of the XML body is populated with the URI The <recipient-uri> element of the XML body is populated with the URI
of the IM Recipient. of the IM Recipient.
If an intermediary receives a SIP MESSAGE request carrying a positive If an intermediary receives a SIP MESSAGE request carrying a positive
delivery notification or a display notification, it forwards it using delivery notification or a display notification, it forwards it using
the rules in Section 8. the rules in Section 8.
13. Transporting Messages using MSRP 13. Transporting Messages using MSRP
MSRP [RFC4975] already provides a built-in mechanism to supply The Message Session Relay Protocol (MSRP) [RFC4975] already provides
positive and negative delivery reports. These reports do not provide a built-in mechanism to supply positive and negative delivery
built-in Display or Processing notifications. However, these reports. These reports do not provide built-in display or processing
notifications in session mode are not as useful as they are for page- notifications. However, these notifications in session-mode are not
mode. This is because the base use case for MSRP is that the as useful as they are for page-mode. This is because the base use
recipient user agent immediately renders SEND requests sequentially, case for MSRP is that the recipient user agent immediately renders
providing the session experience. This is unlike page-mode requests SEND requests sequentially, providing the session experience. This
where a user has to actively initiate the display of the message. is unlike page-mode requests where a user has to actively initiate
That is, they need to click on a button, open a message, and so on to the display of the message. That is, they need to click on a button,
read the message. open a message, and so on to read the message.
If new requirements arise in the future determining the need for IMDN If new requirements arise in the future determining the need for IMDN
in MSRP, new specifications can be drafted. in MSRP, new specifications can be drafted.
14. Security Considerations 14. Security Considerations
IMDNs provide a fine-grained view of the activity of the IM Recipient IMDNs provide a fine-grained view of the activity of the IM
and thus deserves particularly careful confidentiality protection so Recipient, and thus deserve particularly careful confidentiality
that only the intended recipient of the IMDN will receive the IMDN. protection so that only the intended recipient of the IMDN will
In most cases, the intended recipient of the IMDN is the IM Sender. receive the IMDN. In most cases, the intended recipient of the IMDN
is the IM Sender.
Since the IM transport protocol carries the IMDN, all security Since the IM transport protocol carries the IMDN, all security
considerations of the underlying IM protocol also apply to the IMDNs. considerations of the underlying IM protocol also apply to the IMDNs.
The threats in the IMDN system, over and beyond the threats inherent The threats in the IMDN system, over and beyond the threats inherent
to IM include the following: to IM, include the following:
o A malicious endpoint attempts to send messages to a user that o A malicious endpoint attempts to send messages to a user that
would normally not wish to receive messages from that endpoint by would normally not wish to receive messages from that endpoint by
convincing the IMDN system to "bounce" an IMDN from an convincing the IMDN system to "bounce" an IMDN from an
unsuspecting endpoint to the user. unsuspecting endpoint to the user.
o A malicious endpoint attempts to flood an IM Sender with IMDNs by o A malicious endpoint attempts to flood an IM Sender with IMDNs by
convincing a URI-List server to send IMDNs to an unsuspecting IM convincing a URI-List server to send IMDNs to an unsuspecting IM
Sender. Sender.
o A malicious intermediary or node attempts to flood a target node o A malicious intermediary or node attempts to flood a target node
with IMDNs by inserting the target's address in the From field or with IMDNs by inserting the target's address in the From field or
IMDN-Record-Route field IMDN-Record-Route field.
o A malicious node in the network that attempts to modify an IMDN
from an IM Recipient. o A malicious node in the network attempts to modify an IMDN from an
IM Recipient.
o A malicious intermediary attempts to forward an IMDN from an IM o A malicious intermediary attempts to forward an IMDN from an IM
Recipient to the IM Sender, where the IM Recipient would not Recipient to the IM Sender, where the IM Recipient would not
normally forward the IMDN to that IM Sender if the IM Recipient normally forward the IMDN to that IM Sender if the IM Recipient
knew the identity of the IM Sender. knew the identity of the IM Sender.
o A malicious endpoint that attempts to discover for a Request-URI
of an endpoint beyond an intermediary, where the endpoint would o A malicious endpoint attempts to discover the Request-URI of an
normally wish to keep its identity private from the malicious endpoint beyond an intermediary, where the endpoint would normally
endpoint. wish to keep its identity private from the malicious endpoint.
o A malicious node in the network that attempts to eavesdrop on IMDN
o A malicious node in the network attempts to eavesdrop on IMDN
traffic to, for example, learn Request-URI or traffic pattern traffic to, for example, learn Request-URI or traffic pattern
information. information.
o A malicious node in the network attempts to stage a denial of
o A malicious node in the network attempts to stage a denial-of-
service attack on an intermediary by requesting a large list service attack on an intermediary by requesting a large list
expansion. expansion.
The protocol cannot protect against attacks that include the The protocol cannot protect against attacks that include the
following: following:
o A malicious intermediary directly revealing the identity of a o A malicious intermediary directly revealing the identity of a
downstream endpoint that would not normally wish its identity downstream endpoint that would not normally wish its identity
revealed. Keeping such information private is an intermediary revealed. Keeping such information private is an intermediary
implementation issue. implementation issue.
o A malicious IM Recipient that alters the time of the IMDN. There
is no protocol mechanism for ensuring that the IM Recipient does o A malicious IM Recipient alters the time of the IMDN. There is no
not lie about the time or purposely holds an IMDN for transmission protocol mechanism for ensuring that the IM Recipient does not lie
to make it appear that the IM was displayed to the user read later about the time or purposely holds an IMDN for transmission to make
than it actually did. it appear that the IM displayed to the user was read later than it
actually was.
o A deletion attack on an IMDN. This is a trade-off between privacy o A deletion attack on an IMDN. This is a trade-off between privacy
and security. The privacy considerations allow the IM Recipient and security. The privacy considerations allow the IM Recipient
to silently ignore an IMDN request. Any mechanism that would to silently ignore an IMDN request. Any mechanism that would
reliably indicate that a malicious node deleted an IM Recipient's reliably indicate that a malicious node deleted an IM Recipient's
IMDN would also serve the purpose of detecting an IM Recipient IMDN would also serve the purpose of detecting an IM Recipient
that chose not to issue an IMDN. that chose not to issue an IMDN.
To combat eavesdropping, modification, and man-in-the-middle attacks, To combat eavesdropping, modification, and man-in-the-middle attacks,
we require some level of authentication and integrity protections. we require some level of authentication and integrity protections.
That said, there are circumstances where strong integrity would be That said, there are circumstances where strong integrity would be
overkill. The presumption is the IM Sender has and sets the overkill. The presumption is that the IM Sender has, and sets the
expectation for the level of protection. The procedures for expectation for, the level of protection. The procedures for
integrity protection are as follows. integrity protection are as follows.
o If the IM Recipient has a certificate, it MUST sign the IMDN. o If the IM Recipient has a certificate, it MUST sign the IMDN.
Signing the IMDN provides integrity protection. While an Signing the IMDN provides integrity protection. While an
intermediary can replace the IMDN body, the IM Sender (the intermediary can replace the IMDN body, the IM Sender (the
recipient of the IMDN) can validate the signature and note the recipient of the IMDN) can validate the signature and note the
IMDN does not come directly from the IM Receiver. This is not a IMDN does not come directly from the IM Receiver. This is not a
problem if the IM Sender trusts the intermediary. Likewise, an problem if the IM Sender trusts the intermediary. Likewise, an
IMDN in response to a signed IM without a signature indicates IMDN in response to a signed IM without a signature indicates
something bad might have happened. something bad might have happened.
o If the IM is encrypted, the IM Recipient or intermediary MUST o If the IM is encrypted, the IM Recipient or intermediary MUST
encrypt the IMDN body, as an attacker may attempt to discern the encrypt the IMDN body, as an attacker may attempt to discern the
user's activity profile and identity from sniffing IMDNs on the user's activity profile and identity from sniffing IMDNs on the
network. network.
o The two above rules are cumulative. o The two above rules are cumulative.
The IM Recipient or intermediary MUST be capable of accessing the IM The IM Recipient or intermediary MUST be capable of accessing the IM
Sender's public certificate in order to verify the signature in the Sender's public certificate in order to verify the signature in the
IM. IM.
CPIM security considerations [RFC3862] apply here, as this is an CPIM security considerations [RFC3862] apply here, as this is an
extension of CPIM. In order to make the IMDN mechanism independent extension of CPIM. In order to make the IMDN mechanism independent
of the transport protocol, the Work Group made the design choice of of the transport protocol, the Working Group made the design choice
putting routing information into the IMDN application layer payload. of putting routing information into the IMDN application-layer
One consequence of this choice is it eliminates the possibility of payload. One consequence of this choice is it eliminates the
having end-to-end encryption. possibility of having end-to-end encryption.
An attacker can mount a distributed denial of service attack on a An attacker can mount a distributed denial-of-service attack on a
node by sending lots of IMs to the node with IMDN requests. Note node by sending lots of IMs to the node with IMDN requests. Note
that this is the same problem as there is without IMDN; IMDN simply that this is the same problem as there is without IMDN; IMDN simply
linearly increases the load on the node under attack. One can linearly increases the load on the node under attack. One can
mitigate, but not eliminate this threat by the endpoint immediately mitigate, but not eliminate, this threat by the endpoint immediately
ignoring requests that are not authenticated. ignoring requests that are not authenticated.
One way to address the potential for a malicious node to use the IMDN One way to address the potential for a malicious node to use the IMDN
system to anonomize attacks is to log all IMDN requests on the IM system to anonymize attacks is to log all IMDN requests on the IM
Recipient User Agent. This allows for tracking of attacks, if only Recipient user agent. This allows for tracking of attacks, if only
after they occur. Note this also puts a burden on the IM Recipient after they occur. Note this also puts a burden on the IM Recipient
User Agent host. Limited User Agents may not be able to preserve user agent host. Limited user agents may not be able to preserve
much of a log. much of a log.
Likewise, an attacker can mount a denial of service attack on an Likewise, an attacker can mount a denial-of-service attack on an
intermediary by asking the intermediary to explode a large list. intermediary by asking the intermediary to explode a large list.
The following security considerations apply when using IMDNs: The following security considerations apply when using IMDNs.
14.1. Forgery 14.1. Forgery
IMs can be forged. To protect against that, an IM can be signed. An IMs can be forged. To protect against that, an IM can be signed. An
intermediary that receives a signed message and needs to modify any intermediary that receives a signed message and needs to modify any
part of it that is included in the signature (like adding an part of it that is included in the signature (like adding an
Original-To header field to the CPIM header fields), MUST consume the Original-To header field to the CPIM header fields) MUST consume the
IM and create a new copy of it that the intermediary signs itself. IM and create a new copy of it that the intermediary signs itself.
IMDNs may be forged as easily as ordinary IMs. Endpoints and IMDNs may be forged as easily as ordinary IMs. Endpoints and
intermediaries that wish to make automatic use of IMDNs should take intermediaries that wish to make automatic use of IMDNs should take
appropriate precautions to minimize the potential damage from denial- appropriate precautions to minimize the potential damage from denial-
of-service attacks. Security threats related to forged IMDNs include of-service attacks. Security threats related to forged IMDNs include
the sending of a falsified IMDN when the indicated disposition of the the sending of a falsified IMDN when the indicated disposition of the
IM has not actually occurred. For example, display notification IM has not actually occurred. For example, display notification
could be forged to indicate that an IM has been displayed to the could be forged to indicate that an IM has been displayed to the
Recipient. Unsolicited IMDNs is also another form of forgery. Recipient. Unsolicited IMDNs is also another form of forgery.
14.2. Confidentiality 14.2. Confidentiality
There may be cases where an IM Recipient does not wish to reveal the There may be cases where an IM Recipient does not wish to reveal that
information that he has received or in fact read the IM. In this she has received, or in fact read, the IM. In this situation, it is
situation, it is acceptable for the IM Recipient to silently ignore acceptable for the IM Recipient to silently ignore requests for an
requests for an IMDN. It is strongly RECOMMENDED that the IM IMDN. It is strongly RECOMMENDED that the IM Recipient obtain the
Recipient obtain the user's consent before sending an IMDN. user's consent before sending an IMDN. Circumstances where the IM
Circumstances where the IM Recipient does not ask for the user's Recipient does not ask for the user's consent include IM systems
consent include IM systems that, for regulatory reasons, are required that, for regulatory reasons, are required to issue an IMDN, such as
to issue an IMDN, such as in the health care field or financial in the health care field or financial community.
community.
An IM Recipient can obtain such consent by a prompt or dialog box on An IM Recipient can obtain such consent by a prompt or dialog box on
a per-IM basis, globally through the user's setting of a preference, a per-IM basis, globally through the user's setting of a preference,
or other, user-configurable mechanism. The user might also indicate or another, user-configurable mechanism. The user might also
globally that IMDNs are never to be sent or that a "forbidden" IMDN indicate globally that IMDNs are never to be sent or that a
status is always sent in response to a request for an IMDN. "forbidden" IMDN status is always sent in response to a request for
an IMDN.
There are situations where a user sends an IM and requests IMDNs to a There are situations where a user sends an IM and requests IMDNs to a
list whose member information is not disclosed. In this situation, list whose member information is not disclosed. In this situation,
the user will learn of the list members. Therefore, in this case, the user will learn of the list members. Therefore, in this case,
the URI-List server MUST remove any information about list members. the URI-List server MUST remove any information about list members.
If the number of members in the list is also not disclosed, the URL- If the number of members in the list is also not disclosed, the URI-
List server MUST only deliver one aggregated IMDN. Alternatively, List server MUST only deliver one aggregated IMDN. Alternatively,
the URI-list server MAY reject the IM. the URI-list server MAY reject the IM.
It is possible for a list server to not understand IMDN. IM It is possible for a list server to not understand IMDN. IM
Recipients may note the To header field is a list name and not the IM Recipients may note the To header field is a list name and not the IM
Recipient's name. In this case, the IM Recipient can take the Recipient's name. In this case, the IM Recipient can take the
appropriate action if it wishes to keep its identity private. appropriate action if it wishes to keep its identity private.
An unencrypted IMDN could reveal confidential information about an An unencrypted IMDN could reveal confidential information about an
encrypted IM. The same level of security applied to an IM MUST be encrypted IM. The same level of security applied to an IM MUST be
applied to its IMDNs. For example, if an IM is signed and encrypted, applied to its IMDNs. For example, if an IM is signed and encrypted,
the IMDN must be signed and encrypted. the IMDN must be signed and encrypted.
14.3. IMDN as a Certified Delivery Service 14.3. IMDN as a Certified Delivery Service
IMDNs cannot be relied on as a guarantee that an IM was or was not IMDNs cannot be relied on as a guarantee that an IM was or was not
seen by the user. Even if IMDNs are not actively forged, they may be seen by the user. Even if IMDNs are not actively forged, they may be
lost in transit. Moreover, the IM Recipient may bypass the IMDN lost in transit. Moreover, the IM Recipient may bypass the IMDN
issuing mechanism through policy or manipulation of their User Agent issuing mechanism through policy or manipulation of their user agent
Server. Server.
15. IANA Considerations 15. IANA Considerations
15.1. message/imdn+xml MIME TYPE 15.1. message/imdn+xml MIME TYPE
This document registers a new MIME type "message/imdn+xml", and This document registers a new MIME type "message/imdn+xml", and
registers a new XML name space. registers a new XML name space.
This specification follows the guidelines of RFC 3023 [RFC3023]. This specification follows the guidelines of RFC 3023 [RFC3023].
skipping to change at page 34, line 48 skipping to change at page 35, line 14
MIME subtype name: imdn+xml MIME subtype name: imdn+xml
Mandatory parameters: none Mandatory parameters: none
Optional parameters: Same as charset parameter application/xml as Optional parameters: Same as charset parameter application/xml as
specified in RFC 3023 [RFC3023]. specified in RFC 3023 [RFC3023].
Encoding considerations: Same as encoding considerations of Encoding considerations: Same as encoding considerations of
application/xml as specified in RFC 3023 [RFC3023]. application/xml as specified in RFC 3023 [RFC3023].
Security considerations: See section 10 of RFC 3023 [RFC3023] and Security considerations: See Section 10 of RFC 3023 [RFC3023] and
Section 14 of this document. Section 14 of this document.
Interoperability considerations: none. Interoperability considerations: none
Published specification: This document. Published specification: This document
Applications which use this media type: This document type is used to Applications which use this media type: This media type is used to
support CPIM based instant messaging. support CPIM-based instant Messaging.
Additional information: None Additional information: none
Magic number: None Magic number: none
File extension: .cl or .xml File extension: .cl or .xml
Macintosh file type code: "TEXT" Macintosh file type code: "TEXT"
Personal and email address for further information: Hisham Khartabil Personal and email address for further information: Hisham Khartabil
(hisham.khartabil@gmail.com) (hisham.khartabil@gmail.com)
Intended Usage: COMMON Intended Usage: COMMON
Author/change controller: The IETF . Author/change controller: The IETF
15.2. XML Registration 15.2. XML Registration
This section registers a new XML name space and schema, as per This section registers a new XML name space and schema, as per
guidelines in the IETF XML Registry [IANA]. guidelines in the IETF XML Registry [IANA].
URI: The URI for this name space is urn:ietf:params:xml:ns:imdn. URI: urn:ietf:params:xml:ns:imdn
XML: The schema for this name space is in Section 11.1.9 above. XML: The schema for this name space is in Section 11.1.9 above.
Registrant Contact: IETF, SIMPLE working group, Hisham Khartabil Registrant Contact: IETF, SIMPLE working group, Hisham Khartabil
(hisham.khartabil@gmail.com) . (hisham.khartabil@gmail.com)
15.3. Registration for urn:ietf:params:imdn 15.3. URN Registration for IMDN Header Parameters
Registry name: imdn Per [RFC3553], please establish the following registry. New entries
to the registry are Specification Required.
Specification: RFC XXXX. Additional values may be defined by a Registry name: urn:ietf:params:imdn
Standards Action [RFC2434] that updates or obsoletes RFC XXXX.
Repository: [RFC EDITOR: fill in by IANA] Specification: RFC 5438
Index value: The index value is a CPIM message IMDN header name, Repository: RFC 5438
which may consist of a sequence from a restricted set of US-ASCII
characters, as defined above.
URN Formation: The URI for a header is formed from its name by: Index value: Values subordinate to urn:ietf:params:imdn require RFC
publication. The index value is the IMDN header name. The index
value must follow the rules for a legal IMDN header name. In
particular, the IMDN header name, and thus the index value to
register, must be a string of octets taken from the restricted set of
US-ASCII characters per Section 3.1 of [RFC3553]. The index value is
case sensitive.
URN Formation: The URI for a header is formed from its name by
a) replacing any non-URN characters (as defined by RFC 2141[URN]) a) replacing any non-URN characters (as defined by RFC 2141[URN])
with the corresponding '%hh' escape sequence (per RFC 3986 with the corresponding '%hh' escape sequence (per RFC 3986
[RFC2396]); and [RFC3986]) and
b) prepending the resulting string with 'urn:ietf:params:imdn:'. b) prepending the resulting string with 'urn:ietf:params:imdn:'.
Thus, the URI corresponding to the CPIM message IMDN header Thus, the URI corresponding to the CPIM message IMDN header
'Disposition-Notification:' would be 'Disposition-Notification:' would be
'urn:ietf:params:imdn:Disposition-Notification'. 'urn:ietf:params:imdn:Disposition-Notification'.
Initial values; Initial values:
(preamble)
+--------------------------+---------------------+ +--------------------------+---------------------+
| Index Value | Reference | | Index Value | Reference |
+--------------------------+---------------------+ +--------------------------+---------------------+
| Disposition-Notification | RFCXXXX Section 6.2 | | Disposition-Notification | RFC5438 Section 6.2 |
| Message-ID | RFCXXX Section 6.3 | | Message-ID | RFC5438 Section 6.3 |
| Original-To | RFCXXX Section 6.4 | | Original-To | RFC5438 Section 6.4 |
| IMDN-Record-Route | RFCXXX Section 6.5 | | IMDN-Record-Route | RFC5438 Section 6.5 |
| IMDN-Route | RFCXXX Section 6.6 | | IMDN-Route | RFC5438 Section 6.6 |
+--------------------------+---------------------+ +--------------------------+---------------------+
(postamble)
15.4. Content-Disposition: notification 15.4. Content-Disposition: notification
This document registers one new Content-Disposition header field This document registers one new Content-Disposition header field
"disposition-types": notification. The authors request that this "disposition-types": notification, which has been recorded in the
value be recorded in the IANA registry for Mail Content Dispositions. IANA registry for Mail Content Dispositions.
Descriptions of this "disposition-types", including motivation and Descriptions of this "disposition-types", including motivation and
examples, are given in Section 7.2.1.1 and Section 9. examples, are given in Section 7.2.1.1 and Section 9.
Short descriptions suitable for the IANA registry are: Short descriptions suitable for the IANA registry are:
notification the body of the message is a notification according to notification: the payload of the message carrying this Content-
an earlier request for a disposition notification to an instant Disposition header field value is an Instant Message Disposition
message Notification as requested in the corresponding Instant Message.
16. Acknowledgements 16. Acknowledgements
Special thanks to Jari Urpalainen for the thorough review and Special thanks to Jari Urpalainen for the thorough review and
suggestions for the RelaxNG Schema. suggestions for the RelaxNG schema.
The authors would also like to thank Paul Kyzivat, Ben Campbell, Adam The authors would also like to thank Paul Kyzivat, Ben Campbell, Adam
Roach, Gonzalo Camarillo, Frank Ellermann, Sean Olson, Eva Leppanen, Roach, Gonzalo Camarillo, Frank Ellermann, Sean Olson, Eva Leppanen,
Miguel Garcia, Eric McMurry, Jon Peterson, and Robert Sparks for Miguel Garcia, Eric McMurry, Jon Peterson, and Robert Sparks for
their comments and support. In addition, we would like to thank the their comments and support. In addition, we would like to thank the
Gen-Art reviewer extrodinaire, Spencer Dawkins. Gen-Art reviewer extraordinaire, Spencer Dawkins.
17. References 17. References
17.1. Normative References 17.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434, IANA Considerations Section in RFCs", BCP 26, RFC 5226,
October 1998. May 2008.
[RFC3862] Klyne, G. and D. Atkins, "Common Presence and Instant [RFC3862] Klyne, G. and D. Atkins, "Common Presence and Instant
Messaging (CPIM): Message Format", RFC 3862, August 2004. Messaging (CPIM): Message Format", RFC 3862, August 2004.
[IANA] Mealling, M., "The IETF XML Registry", RFC 3688, [IANA] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004. January 2004.
[URN] Moats, R., "The URN Syntax", RFC 2141, May 1997. [URN] Moats, R., "URN Syntax", RFC 2141, May 1997.
[RFC3023] Murata, M., "XML Media Types", RFC 3023, March 1997. [RFC3023] Murata, M., St. Laurent, S., and D. Kohn, "XML Media
Types", RFC 3023, January 2001.
[XML] Bray, T., "Extensible Markup Language (XML) 1.0 (Second [XML] Bray, T., "Extensible Markup Language (XML) 1.0 (Second
Edition)", W3C CR CR-xml11-20011006, October 2000. Edition)", W3C CR CR-xml11-20011006, October 2000.
[RFC2396] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005. RFC 3986, January 2005.
17.2. Informative References 17.2. Informative References
[RFC3261] Rosenberg et al., J., Shulzrinne, H., Camarillo, G., [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
Johnston, A., Peterson, J., Sparks, R., Handley, M., and A., Peterson, J., Sparks, R., Handley, M., and E.
E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, Schooler, "SIP: Session Initiation Protocol", RFC 3261,
June 2002. June 2002.
[RFC3428] Campbell, B., "SIP Extension for Instant Messaging", [RFC3428] Campbell, B., Rosenberg, J., Schulzrinne, H., Huitema, C.,
RFC 3428, December 2002. and D. Gurle, "Session Initiation Protocol (SIP) Extension
for Instant Messaging", RFC 3428, December 2002.
[RFC2821] Klensin, J., "Simple Mail Transfer Protocol", RFC 2821, [RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
April 2001. October 2008.
[RFC3798] Hansen, T. and G. Vaudreuil, "Message Disposition [RFC3798] Hansen, T. and G. Vaudreuil, "Message Disposition
Notification", RFC 3798, May 2004. Notification", RFC 3798, May 2004.
[RFC4975] Campbell, B., Mahy, R., and C. Jennings, "The Message [RFC4975] Campbell, B., Mahy, R., and C. Jennings, "The Message
Session Relay Protocol (MSRP)", RFC 4975, September 2007. Session Relay Protocol (MSRP)", RFC 4975, September 2007.
[URN_NS] Moats, R., "The URN Namespace for IETF Documents", [RFC3553] Mealling, M., Masinter, L., Hardie, T., and G. Klyne, "An
RFC 2648, August 1999. IETF URN Sub-namespace for Registered Protocol
Parameters", BCP 73, RFC 3553, June 2003.
[I-D.ietf-sip-uri-list-message] [URN_NS] Moats, R., "A URN Namespace for IETF Documents", RFC 2648,
Garcia-Martin, M. and G. Camarillo, "Multiple-Recipient August 1999.
[RFC5365] Garcia-Martin, M. and G. Camarillo, "Multiple-Recipient
MESSAGE Requests in the Session Initiation Protocol MESSAGE Requests in the Session Initiation Protocol
(SIP)", draft-ietf-sip-uri-list-message-03 (work in (SIP)", RFC 5365, October 2008.
progress), December 2007.
Authors' Addresses Authors' Addresses
Eric Burger Eric Burger
Unaffiliated
New Hampshire New Hampshire
USA USA
Phone: Phone:
Fax: +1 603 457 5933 Fax: +1 603 457 5933
Email: eburger@standardstrack.com EMail: eburger@standardstrack.com
Hisham Khartabil Hisham Khartabil
Ericsson Australia Ericsson Australia
Melbourne Melbourne
Australia Australia
Phone: +61 416 108 890 Phone: +61 416 108 890
Email: hisham.khartabil@gmail.com EMail: hisham.khartabil@gmail.com
Full Copyright Statement Full Copyright Statement
Copyright (C) The IETF Trust (2008). Copyright (C) The IETF Trust (2009).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
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