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'8') (Obsoleted by RFC 3851) == Outdated reference: A later version (-19) exists of draft-ietf-simple-message-sessions-15 -- Obsolete informational reference (is this intentional?): RFC 2821 (ref. '12') (Obsoleted by RFC 5321) -- Obsolete informational reference (is this intentional?): RFC 2298 (ref. '13') (Obsoleted by RFC 3798) == Outdated reference: A later version (-06) exists of draft-niemi-simple-chat-04 == Outdated reference: A later version (-03) exists of draft-ietf-sip-uri-list-message-00 Summary: 7 errors (**), 0 flaws (~~), 7 warnings (==), 10 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 SIMPLE E. Burger 3 Internet-Draft Cantata Technology 4 Intended status: Informational H. Khartabil 5 Expires: May 31, 2007 Telio 6 November 27, 2006 8 Instant Message Disposition Notification 9 draft-ietf-simple-imdn-02 11 Status of this Memo 13 By submitting this Internet-Draft, each author represents that any 14 applicable patent or other IPR claims of which he or she is aware 15 have been or will be disclosed, and any of which he or she becomes 16 aware will be disclosed, in accordance with Section 6 of BCP 79. 18 Internet-Drafts are working documents of the Internet Engineering 19 Task Force (IETF), its areas, and its working groups. Note that 20 other groups may also distribute working documents as Internet- 21 Drafts. 23 Internet-Drafts are draft documents valid for a maximum of six months 24 and may be updated, replaced, or obsoleted by other documents at any 25 time. It is inappropriate to use Internet-Drafts as reference 26 material or to cite them other than as "work in progress." 28 The list of current Internet-Drafts can be accessed at 29 http://www.ietf.org/ietf/1id-abstracts.txt. 31 The list of Internet-Draft Shadow Directories can be accessed at 32 http://www.ietf.org/shadow.html. 34 This Internet-Draft will expire on May 31, 2007. 36 Copyright Notice 38 Copyright (C) The Internet Society (2006). 40 Abstract 42 Instant Messaging (IM) refers to the transfer of messages between 43 users in real-time. This document provides a mechanism whereby 44 endpoints can request Instant Message Disposition Notifications 45 (IMDN), including delivery, processing and read notifications, for 46 page-mode as well as session mode instant messages. 48 The Common Profile for Instant Messaging (CPIM) data format specified 49 in RFC 3862 is extended with new headers that enable endpoints to 50 request IMDNs. A new message format is also defined to convey IMDNs. 52 This document also describes how SIP and MSRP entities behave using 53 this extension. 55 Table of Contents 57 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 58 2 Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 4 59 3 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 60 4 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 61 5 Disposition Types . . . . . . . . . . . . . . . . . . . . . . 6 62 5.1 Delivery . . . . . . . . . . . . . . . . . . . . . . . . . 6 63 5.2 Processing . . . . . . . . . . . . . . . . . . . . . . . . 7 64 5.3 Read . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 65 6 New CPIM Header Fields . . . . . . . . . . . . . . . . . . . . 7 66 6.1 CPIM Header Namespace . . . . . . . . . . . . . . . . . . . 7 67 6.2 Disposition-Notification . . . . . . . . . . . . . . . . . 8 68 6.3 Message-ID . . . . . . . . . . . . . . . . . . . . . . . . 8 69 6.4 Original-To . . . . . . . . . . . . . . . . . . . . . . . . 8 70 6.5 IMDN-Record-Route . . . . . . . . . . . . . . . . . . . . . 8 71 6.6 IMDN-Route . . . . . . . . . . . . . . . . . . . . . . . . 8 72 7 Endpoint Behaviour . . . . . . . . . . . . . . . . . . . . . . 9 73 7.1 IM Sender . . . . . . . . . . . . . . . . . . . . . . . . . 9 74 7.1.1 Constructing Instant Messages . . . . . . . . . . . . . 9 75 7.1.2 Matching IMs with IMDNs . . . . . . . . . . . . . . . . 10 76 7.1.3 Aggregation of IMDNs . . . . . . . . . . . . . . . . . 10 77 7.1.4 Keeping State . . . . . . . . . . . . . . . . . . . . . 11 78 7.2 IM Recipient . . . . . . . . . . . . . . . . . . . . . . . 12 79 7.2.1 Constructing IMDNs . . . . . . . . . . . . . . . . . . 12 80 8 Intermediary Behaviour . . . . . . . . . . . . . . . . . . . . 14 81 8.1 Constructing Processing Notifications . . . . . . . . . . . 15 82 8.2 Aggregation of IMDNs . . . . . . . . . . . . . . . . . . . 16 83 9 Identifying Messages . . . . . . . . . . . . . . . . . . . . . 17 84 10 Header Fields Formal Syntax . . . . . . . . . . . . . . . . . 17 85 11 IMDN Format . . . . . . . . . . . . . . . . . . . . . . . . . 18 86 11.1 Structure of XML-Encoded IMDN Payload . . . . . . . . . . . 18 87 11.1.1 The Element . . . . . . . . . . . . . . . 18 88 11.1.2 The Element . . . . . . . . . . . . . . . . 19 89 11.1.3 The Element . . . . . . . . . . . . . . 19 90 11.1.4 The Element . . . . . . . . . 19 91 11.1.5 The Element . . . . . . . . . . . . . . . . . 19 92 11.1.6 The Element . . . . . . . . . . . . . . . 19 93 11.1.7 The Element . . . . . . . . . . . . . . . . . 19 94 11.1.8 The Element . . . . . . . . . . . . . . . . . . 20 95 11.2 MIME Type for IMDN Paylaod . . . . . . . . . . . . . . . . 20 96 11.3 The RelaxNG Schema . . . . . . . . . . . . . . . . . . . . 20 97 12 Transporting Messages using SIP . . . . . . . . . . . . . . . 23 98 12.1 Endpoint Behaviour . . . . . . . . . . . . . . . . . . . . 24 99 12.1.1 Sending Requests . . . . . . . . . . . . . . . . . . . 24 100 12.1.2 Sending Responses . . . . . . . . . . . . . . . . . . . 24 101 12.1.3 Receiving Requests . . . . . . . . . . . . . . . . . . 24 102 12.2 Intermediary Behaviour . . . . . . . . . . . . . . . . . . 25 103 13 Transporting Messages using MSRP . . . . . . . . . . . . . . . 26 104 14 Security Considerations . . . . . . . . . . . . . . . . . . . 26 105 14.1 Forgery . . . . . . . . . . . . . . . . . . . . . . . . . . 28 106 14.2 Confidentiality . . . . . . . . . . . . . . . . . . . . . . 29 107 14.3 Non-Repudiation . . . . . . . . . . . . . . . . . . . . . . 29 108 15 IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30 109 15.1 message/imdn+xml MIME TYPE . . . . . . . . . . . . . . . . 30 110 15.2 URN Sub-Namespace Registration for 111 urn:ietf:params:xml:ns:imdn . . . . . . . . . . . . . . . . 31 112 15.3 Schema Registration . . . . . . . . . . . . . . . . . . . . 31 113 15.4 Message/CPIM Header Field registration . . . . . . . . . . 31 114 15.5 Content-Disposition: notification . . . . . . . . . . . . . 31 115 16 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 32 116 17. References . . . . . . . . . . . . . . . . . . . . . . . . . . 32 117 17.1 Normative References . . . . . . . . . . . . . . . . . . . 32 118 17.2 Informative References . . . . . . . . . . . . . . . . . . 32 119 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 33 120 Intellectual Property and Copyright Statements . . . . . . . . . . 34 122 1 Introduction 124 In many user-to-user message exchange systems, message senders often 125 wish to know if the human recipient actually received or read a 126 message. 128 Electronic Mail [12] deals with this situation with Message Delivery 129 Notifications [13]. After the recipient views the message, her mail 130 user agent generates a Message Delivery Notification, or MDN. The 131 MDN is an e-mail that follows the format prescribed by RFC2298 [13]. 132 The fixed format ensures that an automaton can process the message. 134 Message/CPIM [2] is a message format used to generate instant 135 messages. SIP [9] can carry instant messages generated using 136 message/CPIM in SIP MESSAGE requests [10]. The MSRP [11] SEND 137 request can also be used to carry Message/CPIM messages. 139 This document extends Message/CPIM message format (much like Message 140 Delivery Notifications [13] extends Electronic Mail [12]) to enable 141 Instant Message Senders to request, create and send Instant Message 142 Disposition Notifications (IMDN) for a page-mode as well as session 143 mode instant messages. IMDNs include positive delivery, negative 144 delivery (i.e. a message did not get delivered successfully), read 145 notifications as well as processed notifications. By using CPIM 146 headers, the IMDN request and delivery are abstracted outside the 147 transport protocol allowing interoperability between different IM 148 systems. Likewise, the mechanism does not rely on session-mode 149 versus page-mode. 151 This document also describes how SIP and MSRP entities behave using 152 this extension. 154 2 Conventions 156 In this document, the key words 'MUST', 'MUST NOT', 'REQUIRED', 157 'SHALL', 'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', 158 and 'OPTIONAL' are to be interpreted as described in RFC 2119 [1] and 159 indicate requirement levels for compliant implementations. 161 3 Terminology 163 o IM: An Instant Message generated using the Message/CPIM format. 165 o IMDN: An Instant Message Disposition Notification generated using 166 the Message/CPIM format that carries a IMDN XML document. 168 o Message: an IM or an IMDN generated using the Message/CPIM format. 170 o IM Sender: An endpoint (User Agent) generating and sending an IM. 171 It is also the endpoint that requests IMDNs for an IM. Quite 172 often, the IM Sender is the IMDN Recipient, but that is not always 173 true. 175 o IM Recipient: An endpoint (User Agent) that receives IMs. It is 176 also the endpoint that generates and sends IMDNs to IMs, if 177 requested by the IM Sender. 179 o Endpoint: An IM Sender or an IM Recipient. 181 o Intermediary: An entity in the network that is on the path of an 182 IM to its final destination. 184 o IMDN Payload or XML Document: An XML document carrying the 185 disposition notification information. It is always of MIME type 186 "message/imdn+xml". 188 o Disposition type: the type of IMDN that can be requested. This 189 specification defines three, namely "delivery", "processing" and 190 "read" disposition types. 192 o Transport Protocol Message: An IM or an IMDN wrapped in a 193 transport protocol like SIP or MSRP. 195 4 Overview 197 The basic protocol flow is depicted in the diagram below. An IM 198 Sender creates an IM, adds to it IMDN request information it is 199 interested in receiving, then sends its. At a certain point in time, 200 the IM Recipient or an intermediary determines that the user or 201 application has received, did not receive or has read the IM or 202 otherwise disposed the IM. The mechanism by which an IM Recipient 203 determines its user has read an IM is beyond the scope of this 204 document. At that point, the IM Recipient or intermediary 205 automatically generates a notification message to the IM Sender. 206 This notification message is the Instant Message Disposition 207 Notification (IMDN). 209 +--------------+ +--------------+ 210 | IM Sender | | IM Recipient | 211 |IMDN Recipient| | IMDN Sender | 212 +--------------+ +--------------+ 213 | | 214 | | 215 | 1. IM requesting IMDN | 216 |-------------------------------------->| 217 | | 218 | | 219 | 2. IMDN (disposition) | 220 |<--------------------------------------| 221 | | 222 | | 224 Note that the recipient of an IMDN, in some instances, may not be the 225 IM Sender. This is specifically true for page-mode IMs where the 226 Address of Record (AOR) of the IM Sender, that is present in the 227 IMDN, resolves to a different location to where the IM originated. 228 For simplicity, the rest of this document assumes that the IM Sender 229 and the IMDN Recipient are the same and therefore will refer to both 230 as the IM Sender. 232 5 Disposition Types 234 There are three broad categories of disposition states. They are 235 delivery, processing and read. Future extensions may introduce 236 others. 238 5.1 Delivery 240 The delivery notification type indicates whether the IM has been 241 delivered to the IM Recipient or not. The delivery notification type 242 can have the following states: 244 o "delivered" to indicate successful delivery. 246 o "failed" to indicate failure in delivery. 248 o "forbidden" indicate denial by the IM Recipient for the IM Sender 249 to receive the requested IMDN. 251 o "error" to indicate an error in determining the fate of an IM. 253 5.2 Processing 255 The processing notification type indicates that an IM has been 256 processed by an intermediary. The processing notification type can 257 have the following states: 259 o "processed" is a general state of the IM indicating it has been 260 processed. 262 o "stored" state indicates that the IM has been stored by the 263 intermediary for later delivery. 265 o "forbidden" indicate denial by the IM Recipient for the IM Sender 266 to receive the requested IMDN. 268 o "error" to indicate an error in determining the fate of an IM. 270 5.3 Read 272 The read notification type indicates whether the IM Recipient 273 displayed the IM to the user or not. The read notification type can 274 have the following states: 276 o "read" is a state indicating that the IM has been read. 278 o "forbidden" indicate denial by the IM Recipient for the IM Sender 279 to receive the requested IMDN. 281 o "error" to indicate an error in determining the fate of an IM. 283 Since there is no positive acknowledgement from the user, one cannot 284 determine a priori that the user actually read the IM. Thus one MUST 285 NOT use the protocol described here as a non-repudiation service. 287 6 New CPIM Header Fields 289 This specification extends the CPIM data format specified in RFC 3862 290 [2]. A new namespace is created as well as a number of new CPIM 291 headers. 293 6.1 CPIM Header Namespace 295 Per CPIM [2], this specification defines a new namespace for the CPIM 296 extension headers defined in the following sections. The namespace 297 is: urn:ietf:params:cpim-headers:imdn As per CPIM [2] requirements, 298 the new headers defined in the following sections are prepended by 299 the string "imdn." in CPIM messages. 301 6.2 Disposition-Notification 303 The Disposition-Notification header field is used by the IM Sender to 304 indicate the desire to receive IMDNs, from the IM Recipient, for that 305 specific IM. This header field is not needed if the IM Sender does 306 not request an IMDN. The syntax is defined in Section 10. 308 6.3 Message-ID 310 The Message-ID header field contains a globally unique message 311 identifier that is used by the IM Sender to correlate received IMDNs 312 by comparing its value with the value of the element 313 present in the IMDN payload. This header field is mandatory with 314 sending an IM and requesting an IMDN. IMDNs also carry this header 315 field. The syntax is defined in Section 10. 317 6.4 Original-To 319 The Original-To header field is sometimes added to an IM by an 320 intermediary and populated with of the address of the IM Sender. It 321 is used by the IM Recipient to indicate in the IMDNs (by populating 322 the element) the original address the IM was 323 sent to. This header is mandatory if the intermediary changes the 324 CPIM To header field value. The header MUST NOT appear more than 325 once in an IM. The header field value MUST NOT be changed by an 326 intermediary if it was already present. The syntax is defined in 327 Section 10. 329 6.5 IMDN-Record-Route 331 Intermediaries have the capability of indicating that IMDNs should be 332 sent through it (otherwise, IMDNs will not visit the intermediary). 333 An intermediary that request IMDNs to be sent through itself adds an 334 IMDN-Record-Route header field to the IM. The value of the IMDN- 335 Record-Route header field is set to the address of that intermediary. 336 Multiple IMDN-Record-Route header fields can appear in an IM. The 337 syntax is defined in Section 10. 339 6.6 IMDN-Route 341 The IMDN-Route header field provides routing information by including 342 one or more addresses where an IMDN must be routed through. On 343 creating an IMDN, an IM recipient copies the contents of the IMDN- 344 Record-Route present in the IM into the IMDN-Route of the IMDN. 345 Multiple IMDN-Route header fields can appear in an IMDN. The syntax 346 is defined in Section 10. 348 7 Endpoint Behaviour 350 7.1 IM Sender 352 7.1.1 Constructing Instant Messages 354 An IM is constructed using RFC 3862 [2]. The Content-type header 355 field indicates the MIME type of the request payload. 357 7.1.1.1 Adding a Message-ID Header Field 359 If the IM sender requests the reception of IMDNs, the IM sender MUST 360 include a Message-ID header field. The Message-ID field is populated 361 with a value that is unique with 32 bits of randomness. This header 362 field enables the IM Sender to match any IMDNs with their 363 corresponding IMs. 365 7.1.1.2 Adding a DateTime Header Field 367 Some devices may not implement the concept of "Sent Items" box and 368 therefore no information about an IM is stored. It is therefore 369 necessary to add a time stamp in the IM to indicate when it was sent. 370 This time stamp is returned in the IMDN in order to enable the user 371 to correlate the IM with the IMDN at the human level. The DateTime 372 header field is used for this purpose. The IM MUST contain a 373 DateTime header field if an IMDN is requested. 375 7.1.1.3 Adding a Disposition-Notification Header Field 377 In this specification, the IM Sender can request two types of 378 delivery notifications: a failure delivery notification and a success 379 delivery notification. An IM Sender requests failure delivery 380 notification by including a Disposition-Notification header field 381 with value "negative-delivery". Similarly, a success notification is 382 requested by including a Disposition-Notification header field with 383 value "positive-delivery". Both types of delivery notifications can 384 be requested for the same IM. 386 The IM Sender can request a processing notification by including a 387 Disposition-Notification header field with value "processing". 389 The IM Sender can also request a read notification. It is requested 390 by including a Disposition-Notification header field with value 391 "read". 393 The absence of this header or the presence of the header with empty 394 value indicates that the IM Sender is not requesting any IMDNs. The 395 Disposition-Notification header fields can be comma separated. 397 Future extension may define other disposition notifications not 398 defined in this document. The IM Sender MAY request more than one 399 type of IMDN for a single IM. 401 The formal syntax of the Disposition-Notification header field can be 402 found in Section 10. The following in an example IM where the IM 403 Sender requests positive and negative delivery notifications, but not 404 read notification nor processing notifications: 406 Content-type: Message/CPIM 408 From: Alice 409 To: Bob 410 NS: imdn 411 imdn.Message-ID: 34jk324j 412 DateTime: 2006-04-04T12:16:49-05:00 413 imdn.Disposition-Notification: positive-delivery, negative-delivery 414 Content-type: text/plain 415 Content-length: 12 417 Hello World 419 7.1.2 Matching IMs with IMDNs 421 An IM Sender matches an IMDN to an IM by matching the Message-ID 422 header field value in the IM with the element value in 423 the body of the IMDN. If the IM was delivered to multiple 424 recipients, the IM Sender uses the element or the 425 element in the XML body of the IMDN it 426 received to identify the IM Recipient (IMDN Sender). 428 7.1.3 Aggregation of IMDNs 430 An IM Sender may send an IM to multiple recipients in one Transport 431 Protocol Message (typically using a URI-List server) and request 432 IMDNs. It MAY choose to either get one IMDN from each IM Recipient 433 individually or get an aggregated IMDN (the URI-List server 434 aggregates the IMDNs and send the one or more aggregated IMDNs). The 435 IM Sender requests aggregation by adding the Disposition-Notification 436 header field parameter "aggregate". The absence of such a parameter 437 indicates that the IM Sender does not wish for IMDNs to be 438 aggregated. Aggregation can be requested per disposition type. For 439 example, a IM Sender can request delivery notification to be 440 aggregated but read notifications to be sent individually. For 441 example: 443 Disposition-Notification: positive-delivery;aggregate, read 444 The following is an example of an IM Sender requesting aggregation of 445 both positive delivery notifications and read notifications: 447 Disposition-Notification: positive-delivery;aggregate, read;aggregate 449 An IM Sender that requested an aggregated IMDN MUST be prepared to 450 receive multiple aggregated or non-aggregated IMDNs. See Section 8.2 451 for details. 453 An IM Sender MUST be prepared to receive aggregated IMDNs even if it 454 did not request the URI-List server to do so. See again Section 8.2 455 for details. Note that the "aggregate" parameter is a hint for 456 intermediaries and does not require the intermediaries to aggregate 457 IMDNs. 459 7.1.4 Keeping State 461 This specification does not mandate the IM Sender to keep state for a 462 sent IM. 464 Once an IM Sender sends an IM containing an IMDN request, it MAY 465 preserve the IM context, principally the Message-ID, and other user- 466 identifiable information such as the IM subject or content, and date 467 and time it was sent. Without preservation of the IM context, the IM 468 Sender will not be able to correlate the IMDN with the IM it sent. 469 The IM Sender may find it impossible to preserve IM state if it has 470 limited resources or does not have non-volatile memory and then loses 471 power. 473 There is, however, the concept of "Sent Items" box in an application 474 that stores sent IMs. This "Sent Items" box has the necessary 475 information and may have a fancy user interface indicating the state 476 of a sent IM. Unique Message-ID for this purpose proves to be 477 useful. The length of time for items to remain in the "Sent Items" 478 box is a user choice. The user is usually free to keep or delete 479 items from the "Sent Items" box as she pleases or as the memory on 480 the device reaches capacity. 482 Clearly, if an IM Sender loses its sent items state (user deletes 483 items from the "Send Items" box), the client may use a different 484 display strategy in response to apparently unsolicited IMDNs. 486 This specification also does not mandate an IM Sender to run any 487 timers waiting for an IMDN. There are no time limits associated with 488 when IMDNs may be received. 490 IMDNs may legitimately never be received. On the other hand, and 491 IMDN may simply take a very long time. Some clients may choose to 492 purge the state associated with the sent IM. This is the reason for 493 adding the time stamp in the IM and having it returned in the IMDN. 494 This gives the user some opportunity of remembering what IM was sent. 495 For example if the IMDN indicates that the IM the user sent at 2 p.m. 496 last Thursday was delivered, the user has a chance of remembering 497 that they sent an IM at 2 p.m. last Thursday. 499 7.2 IM Recipient 501 7.2.1 Constructing IMDNs 503 IM recipients examine the contents of the Disposition-Notification 504 header field of the CPIM message to determine if an IMDN must be 505 generated for that IM. Disposition-Notification header fields of 506 CPIM messages can include one or more values. This implies that IM 507 recipients may need to generate zero, one, or more IMDNs for that IM, 508 for example a delivery notification as well as a read notification. 509 In this case the IM Recipient MUST be able to construct multiple 510 IMDNs per IM. An IM Recipient MUST NOT construct more than one IMDN 511 per disposition type. I.e. It must not, for example, generate a 512 delivery notification indicating "delivered" then followed by a 513 delivery notification indicating "failed" for the same IM. If the IM 514 Sender requested only failure notifications and the IM was 515 successfully delivered, then no IMDNs will be generated. 517 The IM Recipient MUST NOT generate processing notifications. 519 Disposition-Notification header MUST NOT appear in an IMDN since it 520 does not make sense and is therefore forbidden to request an IMDN for 521 an IMDN. IM Sender MUST ignore it if present. The IM Sender MUST 522 NOT send an IMDN to an IMDN. 524 An IMDN MUST contain a Message-ID header field. The same rules of 525 uniqueness for the Message-ID header field that appears in an IM 526 apply to an IMDN. 528 An IM may contain a IMDN-Record-Route header field (see Section 8 for 529 details). If IMDN-Record-Route header fields appear in the IM, the 530 IM Recipient constructing the IMDN MUST copy the contents of the 531 IMDN-Record-Route header fields into IMDN-Route header fields in the 532 IMDN and maintain the order. The IMDN is then sent to the address in 533 the top IMDN-Route header field. 535 7.2.1.1 Constructing Delivery Notifications 537 A delivery notification is constructed in a similar fashion as an IM, 538 using RFC 3862 [2]. For delivery notifications, the Content-type 539 MUST be of type "message/imdn+xml". It is an XML document. The 540 schema is described Section 11. The delivery notification MUST 541 contain a Content-Disposition header field with value "notification". 542 This indicates to the IM Sender that the message is an IMDN to an IM 543 it has earlier sent. 545 An example looks like the following: 547 Content-type: Message/CPIM 549 From: Bob 550 To: Alice 551 NS: imdn 552 imdn.Message-ID: d834jied93rf 553 Content-type: message/imdn+xml 554 Content-Disposition: notification 555 Content-length: ... 557 558 34jk324j 559 2006-04-04T12:16:49-05:00 560 im:bob@example.com 561 im:bob@example.com 562 563 564 565 566 567 568 The IM was successfully Delivered 569 571 7.2.1.2 Constructing Read Notifications 573 A read notification is constructed in a similar fashion as the 574 delivery notification. See Section 7.2.1.1 for details. 576 An example looks like the following: 578 Content-type: Message/CPIM 580 From: Bob 581 To: Alice 582 NS: imdn 583 imdn.Message-ID: dfjkleriou432333 584 Content-type: message/imdn+xml 585 Content-Disposition: notification 586 Content-length: ... 588 589 34jk324j 590 2006-04-04T12:16:49-05:00 591 im:bob@example.com 592 im:bob@example.com 593 594 595 596 597 598 599 The IM has been read 600 602 There are situations where the IM Recipient cannot determine if or 603 when the IM has been read. The IM Recipient in this case generates a 604 read notification with a value of "error" to indicate an 605 internal error by the server. 607 8 Intermediary Behaviour 609 In this context, application servers (including URI-List servers and 610 Store-and-Forward server) and gateways are defined as intermediaries. 612 An intermediary that forwards an IM MAY change the recipient address 613 in the CPIM To header field when forwarding (for example, a URI-List 614 server changes the IM Recipient address from its own to the address 615 of the final recipient of that IM for every copy it makes to be sent 616 to the list members). In this case, the intermediary MUST add an 617 Original-To header field to the IM populating it with the address 618 that was in the To header field before it was changed. I.e. The 619 Original-To header is populated with the intermediary address. An 620 intermediary MUST NOT add an Original-To header field if one already 621 exists. 623 An intermediary MAY choose to remain on the path of IMDNs for a 624 specific IM. It can do so by adding a CPIM IMDN-Record-Route header 625 field as the top IMDN-Record-Route header and populating it with its 626 own address. An intermediary that does not support this extension 627 will obviously not add the IMDN-Record-Route header. This allows 628 IMDNs to traverse directly from the IM Recipient to the IM Sender 629 even if the IM traversed an intermediary not supporting this 630 extension. 632 An intermediary receiving an IMDN checks the top IMDN-Route header 633 field. If that header field carries the intermediary address, the 634 intermediary pops that header and forwards the IMDN to the address 635 indicated in the now top IMDN-Route header. If no IMDN-Route headers 636 are present, the IMDN is forwarded to the address in the To header 637 field. 639 An intermediary MUST remove any information about the final 640 recipients of a list if the list membership is not disclosed. The 641 intermediary does that by removing the element and/or 642 element from the body of the IMDN before 643 forwarding it to the IM Sender. 645 8.1 Constructing Processing Notifications 647 Intermediaries are the only entities that construct processing 648 notifications. They do so only if the IM Sender has requested a 649 processing notification by including a Disposition-Notification 650 header field with value "processing". 652 The intermediary can create and send processing notifications 653 indicating that an IM has been processed or stored. The intermediary 654 MUST NOT send more than one IMDN for the same disposition type. I.e. 655 It must not send a processing notification indicating that an IM is 656 being "processed" followed by another IMDN indicating that the same 657 IM is "stored". 659 A processing notification is constructed in a similar fashion as the 660 delivery notification. See Section 7.2.1.1 for details. 662 An example looks like the following: 664 Content-type: Message/CPIM 666 From: Bob 667 To: Alice 668 Content-type: message/imdn+xml 669 Content-Disposition: notification 670 Content-length: ... 672 673 34jk324j 674 2006-04-04T12:16:49-05:00 675 im:bob@example.com 676 im:bob@example.com 677 678 679 680 681 682 683 The IM has been processed 684 686 There are situations where the intermediary cannot know the fate of 687 an IM. The intermediary in this case generates a processing 688 notification with a value of "error" to indicate so. 690 8.2 Aggregation of IMDNs 692 In this context, URI-List servers are defined as intermediaries. 694 When a URI-List server receives an IM, it needs to examine 695 Disposition-Notification header fields. If an IMDN request contains 696 the "aggregate" parameter, the URI-List server MUST wait for a 697 configurable period of time or until all recipients have sent the 698 IMDN (whichever comes first) before the URI-List server sends an 699 aggregated IMDN. Note that some IMDNs, for example read 700 notifications, may never come due to user settings. It is an 701 administrator configuration and an implementation issue how long to 702 wait before sending an aggregated IMDN and before a URI-List server 703 removes state for that IM. 705 A URI-List server MAY choose to send multiple aggregated IMDNs even 706 if the requester asked for one aggregated IM. A timer can be started 707 and when it fires, the URI-List server can aggregate whatever IMDNs 708 it has so far for that IM, send the aggregated IMDN and restart the 709 timer for the next batch. This is needed for scenarios where the IM 710 Sender has requested more than one IMDN for a specific IM, for 711 example, delivery notifications as well as read notifications, or 712 when the URI-List server is short on resources and chooses to 713 prioritise forwarding IMs over IMDNs. A second timer can be running 714 and when it fires, the state of the IM is deleted. In this case, the 715 URI-List server consumes any IMDNs that might arrive after that time. 717 A URI-List server MAY aggregate IMDNs even if the IM Sender did not 718 request it to do so. This is to handle the case where the list 719 membership information is not disclosed. The URI-List server MAY 720 also choose to ignore an aggregation request and send individual 721 IMDNs instead. 723 The aggregated IMDN is constructed using the multipart/mixed MIME 724 type and including all the received IMDNs as message/imdn+xml as 725 individual payloads. 727 There are scenarios where an intermediary needs to generate IMDNs, 728 see Section 12.2 for further details. 730 9 Identifying Messages 732 Messages are typically carried in a transport protocol like SIP [9]. 733 The message is an IM if the content-type header field present in it 734 has a value that is NOT "message/imdn+xml". 736 A message is identified as a delivery notification by examining its 737 contents. The message is a delivery notification if: the Content- 738 type header field present has a value of "message/imdn+xml", the 739 Content-Disposition header field has a value of "notification", and 740 the element in that xml body has a sub-element 741 . 743 A message is identified as a processing notification or read 744 notification in a similar fashion as a delivery notification. The 745 difference is that the element in that xml body has a 746 sub-element of and respectively. 748 10 Header Fields Formal Syntax 750 The following syntax specification uses the message header syntax as 751 described in Section 3 of RFC3862 [2]. 753 Header syntax is described without a namespace qualification. 754 Following the rules in RFC3862 [2], header names and other text are 755 case sensitive and MUST be used as given, using exactly the indicated 756 upper-case and lower-case letters. 758 Disposition-Notification = 759 "Disposition-Notification" ": " [(notify-req *(COMMA notify-req))] 760 notify-req = 761 ("negative-delivery" / "positive-delivery" / 762 "processing" / "read" / Token) *(SEMI disp-notif-params) 764 disp-notify-params = "aggregate" / generic-param 766 Message-ID = "Message-ID" ": " Token 768 Original-To = "Original-To" ": " [ Formal-name ] "<" URI ">" 770 IMDN-Record-Route = "IMDN-Record-Route" ": " [ Formal-name ] "<" URI ">" 772 IMDN-Route = "IMDN-Route" ": " [ Formal-name ] "<" URI ">" 774 11 IMDN Format 776 11.1 Structure of XML-Encoded IMDN Payload 778 An IMDN Payload is an XML document [7] that MUST be well-formed and 779 MUST be valid according to schemas, including extension schemas, 780 available to the validater and applicable to the XML document. The 781 IMDN Payload MUST be based on XML 1.0 and MUST be encoded using 782 UTF-8. 784 The namespace identifier for elements defined by this specification 785 is a URN [4], using the namespace identifier 'ietf' defined by [5] 786 and extended by [3]. This urn is: urn:ietf:params:xml:ns:imdn. 788 This namespace declaration indicates the namespace on which the IMDN 789 is based. 791 The root element is . The element has sub-elements, 792 namely , , , , , , , and . 794 Those elements are described in details in the following sections. 796 and can be extended in the future to include 797 new sub-elements not defined in this document. Those new elements 798 MUST be defined in an RFC. 800 11.1.1 The Element 802 The element is mandatory according to the XML schema and 803 carries the message id that appeared in the Message-ID header field 804 of the IM. 806 11.1.2 The Element 808 The element is mandatory and carries the date and time the 809 IM was sent (not the IMDN). This information is obtained from the 810 DateTime header field of the IM. 812 11.1.3 The Element 814 The element is optional and carries the URI of the 815 final recipient. This information is obtained from the To header 816 field of the IM. 818 11.1.4 The Element 820 The element is optional and carries the URI 821 of the original recipient. It MUST be present if the IM carried the 822 Original-To header field. This information is obtained from the 823 Original-To header field of the IM. 825 11.1.5 The Element 827 The element is optional and carries the text that was in 828 the Subject header field, if any. This allows for a human level 829 correlation between an IM and an IMDN. 831 11.1.6 The Element 833 The element is mandatory and carries the disposition 834 type that the IM Sender requested and is being reported. It can 835 carry one of the sub-elements , , or any 836 other future extension. 838 11.1.7 The Element 840 The element is mandatory and carries the result of the 841 disposition request in the element. For disposition 842 type , it can carry one of the sub-elements , 843 , or . For disposition type , it 844 can carry one of the sub-elements , or . 845 For disposition type , it can carry one of the sub- 846 elements , , or . 847 means the disposition was denied. means internal server 848 error. It can also carry any other future extension. 850 11.1.8 The Element 852 The element is optional and carries a human readable text. It 853 has the "lang" attribute that indicates the language the text is 854 written in. 856 11.2 MIME Type for IMDN Paylaod 858 The MIME type for the IMDN Payload is "message/imdn+xml". The IMDN 859 MUST identify the payload as MIME type "message/imdn+xml" in the 860 Content-type header field. 862 11.3 The RelaxNG Schema 864 865 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 898 899 900 901 902 903 904 905 906 907 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 981 982 983 984 985 986 987 988 989 990 991 992 993 995 996 997 999 1000 1001 1002 1003 lang 1004 1005 1006 1007 1008 1009 1011 1012 1013 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1036 1038 12 Transporting Messages using SIP 1039 12.1 Endpoint Behaviour 1041 12.1.1 Sending Requests 1043 A SIP MESSAGE request is constructed using RFC 3428 [10]. The 1044 Content-type header field indicates the MIME type of the request 1045 payload. When using this extension, the Content-type header field 1046 MUST be of MIME type "message/cpim" [2] for both IMs and IMDNs. The 1047 payload is constructed according to Section 7. 1049 A SIP MESSAGE request to multiple recipients is constructed in a 1050 similar manner as a SIP MESSAGE request to a single recipient. The 1051 differences are indicated in [15]. 1053 12.1.2 Sending Responses 1055 An endpoint receiving a SIP MESSAGE request constructs a SIP response 1056 according to RFC3428 [10]. Of course, an endpoint will send a 1057 response to the MESSAGE request regardless of they type of message 1058 (IM or IMDN) is has received, or the disposition type it has been 1059 asked for. 1061 12.1.3 Receiving Requests 1063 12.1.3.1 Instant Message 1065 A SIP MESSAGE request is identified as an IM by examining its 1066 contents according to Section 9. 1068 If an IM Recipient received a SIP MESSAGE request that is an IM that 1069 requested a positive-delivery notification, and that IM Recipient has 1070 constructed and sent a SIP 2xx class response, it MAY generate a 1071 positive-delivery notification after making sure that the IM has been 1072 delivered to the user or application (a GW, for example, can generate 1073 a 2xx response before it has been guaranteed that the final recipient 1074 has actually received the IM). The positive-delivery notification is 1075 constructed according to Section 7.2.1.1. The message is then placed 1076 as the payload in a SIP MESSAGE request. 1078 If an IM Recipient received a SIP MESSAGE request that is an IM that 1079 requested a negative-delivery, and that IM Recipient has constructed 1080 and sent a 2xx class response, it SHOULD generate a negative-delivery 1081 notification if it learnt that the final recipient or application did 1082 not receive the IM (a GW, for example, can generate a 2xx response 1083 before it has been guaranteed that the final recipient has actually 1084 received the IM). The negative-delivery notification is constructed 1085 according to Section 7.2.1.1. The message is then placed as the 1086 payload in a SIP MESSAGE request. 1088 If an IM Recipient received a SIP MESSAGE request that is an IM that 1089 requested a negative-delivery notification, and the IM Recipient has 1090 constructed and sent an error response, it MUST NOT generate a 1091 negative-delivery notification. 1093 If an IM Recipient received a SIP MESSAGE request that is an IM that 1094 requested a read notification, and that IM Recipient has constructed 1095 and sent a SIP 2xx class response, it MAY generate a read 1096 notification after making sure that the IM has been presented to the 1097 user or application. It is outside the scope of this document how 1098 such determination can be made. Note that the option to send a read 1099 notification or not can be left to the user. An application may 1100 allow a user to configure such choice. The read notification is 1101 constructed according to Section 7.2.1.2. The message is then placed 1102 as the payload in a SIP MESSAGE request. 1104 12.1.3.2 Delivery Notification 1106 A SIP MESSAGE request is identified as delivery notification by 1107 examining its contents according to Section 9. 1109 12.1.3.3 Read Notification 1111 A SIP MESSAGE request is identified as read notification by examining 1112 its contents according to Section 9. 1114 12.2 Intermediary Behaviour 1116 In this context, application servers (including URI-List servers and 1117 Store-and-Forward server) and gateways are defined as intermediaries. 1118 SIP Proxies MUST NOT generate IMDNs but MUST forward them like any 1119 other sip request. 1121 A SIP MESSAGE request to multiple recipients is forwarded according 1122 to [15]. 1124 If an intermediary generates a SIP 2xx class response to a SIP 1125 MESSAGE request it has received that is an IM, it examines if the 1126 body was of type "message/cpim". If so, it checks if there is the 1127 header field Disposition-Notification with a value "positive- 1128 delivery" and/or "negative-delivery". If so, it MUST send a delivery 1129 notification after receiving a transactional final response for the 1130 IM. 1132 If the Disposition-Notification header field contains a value of 1133 "positive-delivery", the intermediary MUST NOT generate a delivery 1134 notification if it receives a SIP 2xx class response for the sent IM. 1135 This is in anticipation of a failure downstream after a 2xx response 1136 has been generated. 1138 If the Disposition-Notification header field contains a value of 1139 "negative-delivery", the intermediary SHOULD generate a delivery 1140 notification if it receives a SIP 4xx, 5xx or 6xx class final 1141 response for the sent IM or if it has received a SIP 2xx class 1142 response followed by a negative-delivery notification. 1144 If the Disposition-Notification header field contains a value of 1145 "processing", the intermediary MAY generate a processing notification 1146 after it has forwarded or stored the IM. The rest of the procedures 1147 in Section 8.1 apply. 1149 The procedure for generating such IMDN is the same as that of an IM 1150 Recipient (Section 7.2.1.1). 1152 The element of the XML body is populated with the URI 1153 of the IM Recipient. 1155 If an intermediary receives a SIP MESSAGE request carrying a positive 1156 delivery notification or a read notification, it forwards it using 1157 the rules in Section 8. 1159 13 Transporting Messages using MSRP 1161 IMDN is not generally applicable to MSRP. MSRP already provides a 1162 built-in mechanism to supply positive and negatie delivery reports. 1164 While MSRP does not provide a built-in Read or Processing 1165 notification dispositions, those are generally not considered as 1166 useful information session IM. This is because the assumption behind 1167 MSRP is that SEND requests do not reach a mailbox where incoming IMs 1168 have to be open, but to an application that renders sequentially 1169 those incoming IMs, providing the session experience. This kind of 1170 applications has no means of identifying when a user has read the IM 1171 and therefore cannot useful information for the sender. 1173 If new requirements arise in the future determining the need for IMDN 1174 in MSRP, new specifications can be drafted. 1176 14 Security Considerations 1178 IMDNs provide a fine-grained view of the activity of the IM Recipient 1179 and thus deserves particularly careful confidentiality protection so 1180 that only the intended recipient of the IMDN will receive the IMDN 1181 (in most cases, the intended recipient of the IMDN is the IM Sender). 1183 Since IMDNs are carried by using the IM protocol itself, all security 1184 considerations of the underlying IM protocol also apply to the IMDNs. 1186 The threats in the IMDN system, over and beyond the threats inherent 1187 to IM include the following: 1189 o A malicious endpoint attempts to send messages to a user that 1190 would normally not wish to receive messages from that endpoint by 1191 convincing the IMDN system to "bounce" an IMDN from an 1192 unsuspecting endpoint to the user. 1194 o A malicious endpoint attempts to flood a IM Sender with IMDNs by 1195 convincing a URI-List server to send IMDNs to an unsuspecting IM 1196 Sender. 1198 o A malicious node in the network that attempts to modify an IMDN 1199 from a IM Recipient. 1201 o A malicious intermediary attempts to forward an IMDN from an IM 1202 Recipient to the IM Sender, where the IM Recipient would not 1203 normally forward the IMDN to that IM Sender if the IM Recipient 1204 knew the identity of the IM Sender. 1206 o A malicious endpoint that attempts to fish for a Request-URI of an 1207 endpoint beyond an intermediary , where the endpoint would 1208 normally wish to keep its identity private from the malicious 1209 endpoint. 1211 o A malicious node in the network that attempts to eavesdrop on IMDN 1212 traffic to, for example, learn Request-URI or traffic pattern 1213 information. 1215 o A malicious node in the network attempts to stage a denial of 1216 service attack on an intermediary by requesting a large list 1217 expansion with a request for aggregated IMDN processing. 1219 The protocol cannot protect against attacks that include the 1220 following: 1222 o A malicious intermediary directly revealing the identity of a 1223 downstream endpoint that would not normally wish its identity 1224 revealed. Keeping such information private is an intermediary 1225 implementation issue. 1227 o A malicious IM Recipient that alters the time of the IMDN. There 1228 is no protocol mechanism for ensuring the IM Recipient does not 1229 lie about the time or purposely holds an IMDN for transmission to 1230 make it appear that the user read an IM later than they actually 1231 did. 1233 o A deletion attack on an IMDN. This is a trade-off between privacy 1234 and security. The privacy considerations allow the IM Recipient 1235 to silently ignore an IMDN request. Any mechanism that would 1236 reliably indicate that a malicious node deleted a IM Recipient's 1237 IMDN would also serve the purpose of detecting a IM Recipient that 1238 chose not to issue an IMDN. 1240 To combat eavesdropping, modification, and man-in-the-middle attacks, 1241 we require some level of authentication and integrity protections. 1242 That said, there are circumstances where strong integrity would be 1243 overkill. The presumption is the IM Sender has and sets the 1244 expectation for the level of protection. The procedures for 1245 integrity protection are as follows. 1247 o If the IM Recipient has a certificate, it MUST sign the IMDN. 1249 o If the IM is encrypted, the IM Recipient or intermediary MUST 1250 encrypt the IMDN body, as an attacker may attempt to discern the 1251 user's activity profile and identity from sniffing IMDNs on the 1252 network. 1254 o The two above rules are cumulative. 1256 The IM Recipient or intermediary MUST be capable of loading a user 1257 certificate. 1259 An attacker can mount a distributed denial of service attack on a 1260 node by sending lots of IMs to the node with IMDN requests. Note 1261 that this is the same problem as there is without IMDN; IMDN simply 1262 linearly increases the load on the node under attack. One can 1263 mitigate, but not eliminate this threat by the endpoint immediately 1264 ignoring requests that are not authenticated. 1266 Likewise, an attacker can mount a denial of service attack on an 1267 intermediary by asking the intermediary to explode a large list and 1268 to direct the intermediary to aggregate the IMDNs from the targets of 1269 the list. 1271 The following security considerations apply when using IMDNs: 1273 14.1 Forgery 1275 IMs can be forged. To protect against that, an IM can be signed. An 1276 intermediary that receives a signed message and needs to modify any 1277 part of it that is included in the signature (like adding an 1278 Original-To header to the CPIM headers), MUST consume the IM and 1279 create a new copy of it that the intermediary signs itself. 1281 IMDNs may be forged as easily as ordinary IMs. Endpoints and 1282 intermediaries that wish to make automatic use of IMDNs should take 1283 appropriate precautions to minimize the potential damage from denial- 1284 of-service attacks. Security threats related to forged IMDNs include 1285 the sending of a falsified IMDN when the indicated disposition of the 1286 IM has not actually occurred. For example, read notification could 1287 be forged to indicate that a IM Recipient has read the IM. 1288 Unsolicited IMDNs is also another form of forgery. 1290 14.2 Confidentiality 1292 There may be cases where an IM Recipient does not wish to reveal the 1293 information that he has received or in fact read the IM. In this 1294 situation, it is acceptable for the IM Recipient to silently ignore 1295 requests for an IMDN. It is strongly RECOMMENDED that the IM 1296 Recipient obtain the user's consent before sending an IMDN. 1297 Circumstances where the IM Recipient does not ask for the user's 1298 consent include IM systems that, for regulatory reasons, are required 1299 to issue an IMDN, such as in the health care field or financial 1300 community. 1302 An IM Recipient can obtain such consent by a prompt or dialog box on 1303 a per-IM basis, globally through the user's setting of a preference, 1304 or other, user-configurable mechanism. The user might also indicate 1305 globally that IMDNs are never to be sent or that a "forbidden" IMDN 1306 status is always sent in response to a request for an IMDN. 1308 There are situations where a user sends an IM and requests IMDNs to a 1309 list who's member information is not disclosed. In this situation, 1310 the user will learn of the list members. Therefore, in this case, 1311 the URI-List server MUST remove any information about list members. 1312 If the number of members in the list is also not disclosed, the URL- 1313 List server MUST only deliver one aggregated IMDN. Alternatively, 1314 the URI-list server MAY reject the IM. 1316 An unencrypted IMDN could reveal confidential information about an 1317 encrypted IM. It is a MUST that the same level of security applied 1318 to an IM to be applied to its IMDNs. For example, if an IM is signed 1319 and encrypted, and IMDN must also be signed and encrypted. 1321 14.3 Non-Repudiation 1323 IMDNs cannot be relied on as a guarantee that an IM was or was not 1324 seen by the user. Even if IMDNs are not actively forged, they may be 1325 lost in transit. The IMDN issuing mechanism may be bypassed in some 1326 manner by the IM Recipient. 1328 15 IANA Considerations 1330 15.1 message/imdn+xml MIME TYPE 1332 This document registers a new MIME type "message/imdn+xml", and 1333 registers a new XML namespace. 1335 This specification follows the guidelines of RFC3023 [6]. 1337 MIME media type: message 1339 MIME subtype name: imdn+xml 1341 Mandatory parameters: none 1343 Optional parameters: Same as charset parameter application/xml as 1344 specified in RFC 3023 [6]. 1346 Encoding considerations: Same as encoding considerations of 1347 application/xml as specified in RFC 3023 [6]. 1349 Security considerations: See section 10 of RFC 3023 [6] and 1350 Section 14 of this document. 1352 Interoperability considerations: none. 1354 Published specification: This document. 1356 Applications which use this media type: This document type is used to 1357 support SIP and MSRP based instant messaging. 1359 Additional information: None 1361 Magic number: None 1363 File extension: .cl or .xml 1365 Macintosh file type code: "TEXT" 1367 Personal and email address for further information: Hisham Khartabil 1368 (hisham.khartabil@telio.no) 1370 Intended Usage: COMMON 1372 Author/change controller: The IETF . 1374 15.2 URN Sub-Namespace Registration for urn:ietf:params:xml:ns:imdn 1376 This section registers a new XML namespace, as per guidelines in the 1377 IETF XML Registry [3]. 1379 URI: The URI for this namespace is urn:ietf:params:xml:ns:imdn. 1381 Registrant Contact: IETF, SIMPLE working group, Hisham Khartabil 1382 (hisham.khartabil@telio.no) . 1384 15.3 Schema Registration 1386 This section registers a new XML schema per the procedures in [3]. 1388 URI: urn:ietf:params:xml:ns:imdn 1390 Registrant Contact: IETF, SIMPLE working group, Hisham Khartabil 1391 (hisham.khartabil@telio.no) 1393 The XML for this schema can be found as the sole content of 1394 Section 11.3. 1396 15.4 Message/CPIM Header Field registration 1398 This document registers the following message/cpim header fields in 1399 the cpim-headers registry: 1401 Disposition-Notification - [RFCXXXX] 1403 Message-ID - [RFCXXXX] 1405 Original-To - [RFCXXXX] 1407 IMDN-Record-Route - [RFCXXXX] 1409 IMDN-Route - [RFCXXXX]. 1411 15.5 Content-Disposition: notification 1413 This document registers one new Content-Disposition header 1414 "disposition-types": notification. The authors request that this 1415 values be recorded in the IANA registry for Content-Dispositions. 1416 Descriptions of this "disposition-types", including motivation and 1417 examples, are given in Section 7.2.1.1 and Section 9. Short 1418 descriptions suitable for the IANA registry are: notification the 1419 body of the message is a notification according to an earlier request 1420 for a disposition notification to an instant message 1422 16 Acknowledgements 1424 The authors would like to thank Paul Kyzivat, Ben Campbell, Adam 1425 Roach, Gonzalo Camarillo, Sean Olson, Eva Leppanen, Miguel Garcia, 1426 Eric McMurry and Jari Urpalainen for their comments and support. 1428 17. References 1430 17.1. Normative References 1432 [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement 1433 Levels", BCP 14, RFC 2119, March 1997. 1435 [2] Klyne, G. and D. Atkins, "Common Presence and Instant Messaging 1436 (CPIM): Message Format", RFC 3862, August 2004. 1438 [3] Mealling, M., "The IETF XML Registry", RFC 3688, January 2004. 1440 [4] Moats, R., "The URN Syntax", RFC 2141, May 1997. 1442 [5] Moats, R., "The URN Namespace for IETF Documents", RFC 2648, 1443 August 1999. 1445 [6] Murata, M., "XML Media Types", RFC 3023, March 1997. 1447 [7] Bray, T., "Extensible Markup Language (XML) 1.0 (Second 1448 Edition)", W3C CR CR-xml11-20011006, October 2000. 1450 [8] Ramsdell, B., "S/MIME Version 3 Message Specification", 1451 RFC 2633, June 1999. 1453 17.2. Informative References 1455 [9] Rosenberg et al., J., Shulzrinne, H., Camarillo, G., Johnston, 1456 A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, 1457 "SIP: Session Initiation Protocol", RFC 3261, June 2002. 1459 [10] Campbell, B., "SIP Extension for Instant Messaging", RFC 3428, 1460 December 2002. 1462 [11] Campbell, B., "The Message Session Relay Protocol", 1463 draft-ietf-simple-message-sessions-15, June 2006. 1465 [12] Klensin, J., "Simple Mail Transfer Protocol", RFC 2821, 1466 April 2001. 1468 [13] Fajman, R., "An Extensible Message Format for Message 1469 Disposition Notifications", RFC 2298, March 1998. 1471 [14] Niemi, A., "Multi-part IM Sessions Using MSRP", 1472 draft-niemi-simple-chat-04, February 2006. 1474 [15] Garcia-Martin, M. and G. Camarillo, "Multiple-Recipient MESSAGE 1475 Requests in SIP", draft-ietf-sip-uri-list-message-00.txt, 1476 September 2006. 1478 Authors' Addresses 1480 Eric Burger 1481 Cantata Technology 1482 18 Keewaydin Dr. 1483 Salem, NH 03079-2839 1484 USA 1486 Phone: +1 603 890 7587 1487 Fax: +1 603 457 5944 1488 Email: eburger@cantata.com 1490 Hisham Khartabil 1491 Telio 1492 P.O. 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