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'7') (Obsoleted by RFC 3801) -- Obsolete informational reference (is this intentional?): RFC 2822 (ref. '9') (Obsoleted by RFC 5322) Summary: 5 errors (**), 0 flaws (~~), 6 warnings (==), 5 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 SIPPING WG R. Mahy 3 Internet-Draft Cisco Systems, Inc. 4 Expires: September 1, 2003 March 3, 2003 6 A Message Summary and Message Waiting Indication Event Package for 7 the Session Initiation Protocol (SIP) 8 draft-ietf-sipping-mwi-02.txt 10 Status of this Memo 12 This document is an Internet-Draft and is in full conformance with 13 all provisions of Section 10 of RFC2026. 15 Internet-Drafts are working documents of the Internet Engineering 16 Task Force (IETF), its areas, and its working groups. Note that other 17 groups may also distribute working documents as Internet-Drafts. 19 Internet-Drafts are draft documents valid for a maximum of six months 20 and may be updated, replaced, or obsoleted by other documents at any 21 time. It is inappropriate to use Internet-Drafts as reference 22 material or to cite them other than as "work in progress." 24 The list of current Internet-Drafts can be accessed at http:// 25 www.ietf.org/ietf/1id-abstracts.txt. 27 The list of Internet-Draft Shadow Directories can be accessed at 28 http://www.ietf.org/shadow.html. 30 This Internet-Draft will expire on September 1, 2003. 32 Copyright Notice 34 Copyright (C) The Internet Society (2003). All Rights Reserved. 36 Abstract 38 This draft proposes a SIP event package to carry message waiting 39 status and message summaries from a messaging system to an interested 40 User Agent. 42 Table of Contents 44 1. Conventions . . . . . . . . . . . . . . . . . . . . . . . . 3 45 2. Background and Appropriateness . . . . . . . . . . . . . . . 3 46 3. Event Package Formal Definition . . . . . . . . . . . . . . 4 47 3.1 Event Package Name . . . . . . . . . . . . . . . . . . . . . 4 48 3.2 Event Package Parameters . . . . . . . . . . . . . . . . . . 4 49 3.3 SUBSCRIBE Bodies . . . . . . . . . . . . . . . . . . . . . . 4 50 3.4 Subscription Duration . . . . . . . . . . . . . . . . . . . 4 51 3.5 NOTIFY Bodies . . . . . . . . . . . . . . . . . . . . . . . 4 52 3.6 Subscriber generation of SUBSCRIBE requests . . . . . . . . 6 53 3.7 Notifier processing of SUBSCRIBE requests . . . . . . . . . 6 54 3.8 Notifier generation of NOTIFY requests . . . . . . . . . . . 7 55 3.9 Subscriber processing of NOTIFY requests . . . . . . . . . . 7 56 3.10 Handling of Forked Requests . . . . . . . . . . . . . . . . 7 57 3.11 Rate of notifications . . . . . . . . . . . . . . . . . . . 7 58 3.12 State Agents . . . . . . . . . . . . . . . . . . . . . . . . 8 59 3.13 Behavior of a Proxy Server . . . . . . . . . . . . . . . . . 8 60 4. Examples of Usage . . . . . . . . . . . . . . . . . . . . . 8 61 4.1 Example Message Flow . . . . . . . . . . . . . . . . . . . . 8 62 4.2 Example Usage with Caller Preferences . . . . . . . . . . . 14 63 5. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . 14 64 5.1 New event-package definition . . . . . . . . . . . . . . . . 14 65 5.2 Body Format Syntax . . . . . . . . . . . . . . . . . . . . . 15 66 6. Security Considerations . . . . . . . . . . . . . . . . . . 15 67 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . 15 68 7.1 SIP Event Package Registration for message-summary . . . . . 16 69 7.2 MIME Registration for application/simple-message-summary . . 16 70 8. Revision history . . . . . . . . . . . . . . . . . . . . . . 16 71 8.1 Open Issues . . . . . . . . . . . . . . . . . . . . . . . . 17 72 8.2 Changes from draft-ietf-sipping-mwi-00 . . . . . . . . . . . 17 73 8.3 Changes from draft-mahy-sipping-mwi-00 . . . . . . . . . . . 17 74 8.4 Changes from draft-mahy-sip-mwi-01 . . . . . . . . . . . . . 18 75 8.5 Changes from draft-mahy-sip-mwi-00 . . . . . . . . . . . . . 18 76 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 19 77 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 19 78 Normative References . . . . . . . . . . . . . . . . . . . . 19 79 Informational References . . . . . . . . . . . . . . . . . . 19 80 Author's Address . . . . . . . . . . . . . . . . . . . . . . 20 81 Intellectual Property and Copyright Statements . . . . . . . 21 83 1. Conventions 85 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 86 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 87 document are to be interpreted as described in RFC-2119 [3]. 89 2. Background and Appropriateness 91 Messaging Waiting Indication is a common feature of telephone 92 networks. It typically involves an audible or visible indication 93 that messages are waiting, such as playing a special dial tone 94 (called message-waiting dial tone), lighting a light or indicator on 95 the phone, displaying icons or text, or some combination. 96 Message-waiting dial tone is similar but distinct from stutter dial 97 tone. Both are defined in GR-506 [10]. 99 The methods in the SIP [1] base specification were only designed to 100 solve the problem of session initiation for multimedia sessions, and 101 rendezvous. Since Message Waiting Indication is really status 102 information orthogonal to a session, it was not clear how an IP 103 telephone acting as a SIP User Agent would implement comparable 104 functionality. Members of the telephony community viewed this as a 105 shortcoming of SIP. 107 Users want the useful parts of the functionality they have using 108 traditional analog, mobile, and PBX telephones. It is also desirable 109 to provide comparable functionality in a flexible way that allows for 110 more customization and new features. 112 SIP Specific Event Notification (RFC 3265 -- SIP Events) [2] is an 113 appropriate mechanism to use in this environment, as it preserves the 114 user mobility and rendezvous features which SIP provides. 116 Using SIP-Specific Event Notification, A Subscriber User Agent 117 (typically an IP phone or SIP software User Agent) subscribes to the 118 status of their messages. A SIP User Agent acting on behalf of the 119 user's messaging system then notifies the Subscriber whenever the 120 messaging account's messages have changed. The Notifier sends this 121 message summary information in the body of the NOTIFY, encoded in a 122 new MIME type defined later in this draft. A User Agent can also 123 explicitly fetch the current status. 125 A SIP User Agent MAY subscribe to multiple accounts (distinguished by 126 the Request URI). Multiple SIP User Agents MAY subscribe to the same 127 account. 129 Before any subscriptions or notifications are sent, each interested 130 User Agent must be made aware of its messaging server(s). This MAY 131 be manually configured on interested User Agents, manually configured 132 on an appropriate SIP Proxy, or dynamically discovered using caller 133 preferences [4]. (For more information on usage with caller 134 preferences, see Section 4.2) 136 3. Event Package Formal Definition 138 3.1 Event Package Name 140 This document defines a SIP Event Package as defined in RFC 3265 [2]. 141 The event-package token name for this package is: 143 "message-summary" 145 3.2 Event Package Parameters 147 This package does not define any event package parameters. 149 3.3 SUBSCRIBE Bodies 151 This package does not define any SUBSCRIBE bodies. 153 3.4 Subscription Duration 155 Subscriptions to this event package MAY range from minutes to weeks. 156 Subscriptions in hours or days are more typical and are RECOMMENDED. 157 The default subscription duration for this event package is one hour. 159 3.5 NOTIFY Bodies 161 A simple text-based format is proposed to prevent an undue burden on 162 low-end user agents, for example, inexpensive IP phones with no 163 display. Although this format is text-based, it is intended for 164 machine consumption only. 166 A future extension MAY define other NOTIFY bodies. If no "Accept" 167 header is present in the SUBSCRIBE, the body type defined in this 168 document MUST be assumed. 170 The format specified in this proposal attempts to separate orthogonal 171 attributes of messages as much as possible. Messages are separated 172 by message-context-class (for example: voice-message, fax-message, 173 pager-message, multimedia-message, text-message, and none); by 174 message status (new and old); and by urgent and non-urgent type. 176 The text format begins with a simple status line, and optionally a 177 summary line per message-context-class. Message-context-classes are 178 defined in [6]. For each message-context-class, the total number of 179 new and old messages is reported in the new and old fields. 181 In some cases, detailed message summaries are not available. The 182 status line allows messaging systems or messaging gateways to provide 183 the traditional boolean message waiting notification. 185 Messages-Waiting: yes 187 If the Request-URI or To header in a message-summary subscription 188 corresponds to a group or collection of individual messaging 189 accounts, the notifier MUST specify to which account the 190 message-summary body corresponds. Note that the account URI MUST NOT 191 be delimited with angle brackets ("<" and ">"). 193 Message-Account: sip:alice@example.com 195 In the example that follows, more than boolean message summary 196 information is available to the User Agent. There are two new and 197 four old fax messages. 199 Fax-Message: 2/4 201 After the summary, the format can optionally list a summary count of 202 urgent messages. In the next example there are one new and three old 203 voice messages, none of the new messages are urgent, but one of the 204 old messages is. All counters have a maximum value of 4,294,967,295 205 ((2^32) - 1). Notifiers MUST NOT generate a request with a larger 206 value. Subscribers MUST treat a larger value as 2^32-1. 208 Voice-Message: 1/3 (0/1) 210 Optionally, after the summary counts, the messaging systems MAY 211 append RFC 2822 [9]-style message headers, which further describe 212 newly added messages. Message headers MUST NOT be included in an 213 initial NOTIFY, as new messages could be essentially unbounded in 214 size. Message headers included in subsequent notifications MUST only 215 correspond to messages added since the previous notification for that 216 subscription. A messaging system which includes message headers in a 217 NOTIFY, MUST provide an administrator configurable mechanism for 218 selecting which headers are sent. Likely headers for inclusion 219 include To, From, Date, Subject, and Message-ID. Note that the 220 formatting of these headers is identical to that of SIP 221 extension-headers, not the (similar) format defined in RFC 2822. 223 Implementations which generate large notifications are reminded to 224 follow the message size restrictions for unreliable transports 225 articulated in Section 18.1.1 of SIP. 227 Mapping local message state to new/old message status and urgency is 228 an implementation issue of the messaging system. However, the 229 messaging system MUST NOT consider a message "old" merely because it 230 generated a notification , as this could prevent another subscription 231 from accurately receiving message-summary notifications. Likewise, 232 the messaging system MAY use any suitable algorithm to determine that 233 a message is "urgent". 235 Messaging systems MAY use any algorithm for determining the 236 approporiate message-context-class for a specific message. Systems 237 which use Internet Mail SHOULD use the contents of the 238 Message-Context header [6] (defined in RFC 3458) if present as a hint 239 to make a context determination. Note that a messaging system does 240 not need to support a given context in order to generate 241 notifications identified with that context. 243 3.6 Subscriber generation of SUBSCRIBE requests 245 Subscriber User Agents will typically SUBSCRIBE to message summary 246 information for a period of hours or days, and automatically attempt 247 to re-SUBSCRIBE well before the subscription is completely expired. 248 If re-subscription fails, the Subscriber SHOULD periodically retry 249 again until a subscription is successful, taking care to backoff to 250 avoid network congestion. If a subscription has expired, new 251 re-subscriptions MUST use a new Call-ID. 253 The Subscriber SHOULD SUBSCRIBE to that user's message summaries 254 whenever a new user becomes associated with the device (a new login). 255 The Subscriber MAY also explicitly fetch the current status at any 256 time. The subscriber SHOULD renew its subscription immediately after 257 a reboot, or when the subscriber's network connectivity has just been 258 re-established. 260 The Subscriber MUST be prepared to receive and process a NOTIFY with 261 new state immediately after sending a new SUBSCRIBE, a SUBSCRIBE, 262 renewal, an unSUBSCRIBE or a fetch; or at any time during the 263 subscription. 265 When a user de-registers from a device (logoff, power down of a 266 mobile device, etc.), subscribers SHOULD unsubscribe by sending a 267 SUBSCRIBE message with an Expires header of zero. 269 3.7 Notifier processing of SUBSCRIBE requests 271 When a SIP Messaging System receives SUBSCRIBE messages with the 272 message-summary event-type, it SHOULD authenticate the subscription 273 request. If authentication is successful, the Notifier MAY limit the 274 duration of the subscription to an administrator defined amount of 275 time as described in SIP Events. 277 3.8 Notifier generation of NOTIFY requests 279 Immediately after a subscription is accepted, the Notifier MUST send 280 a NOTIFY with the current message summary information. This allows 281 the Subscriber to resynchronize its state. This initial 282 synchronization NOTIFY MUST NOT include the optional RFC 2822 283 [9]-style message headers. 285 When the status of the messages changes sufficiently for a messaging 286 account to change the number of new or old messages, the Notifier 287 SHOULD send a NOTIFY message to all active subscribers to that 288 account. NOTIFY messages sent to subscribers of a group or alias, 289 MUST contain the message account name in the notification body. 291 A Messaging System MAY send a NOTIFY with an "Expires" header of "0" 292 and a "Subscription-State" header of "terminated" before a graceful 293 shutdown. 295 3.9 Subscriber processing of NOTIFY requests 297 Upon receipt of a valid NOTIFY request, the subscriber SHOULD 298 immediately render the message status and summary information to the 299 end user in an implementation specific way. 301 The Subscriber MUST be prepared to receive NOTIFYs from different 302 Contacts corresponding to the same SUBSCRIBE. (the SUBSCRIBE may 303 have been forked). 305 3.10 Handling of Forked Requests 307 Forked requests are allowed for this event type and may install 308 multiple subscriptions. The Subscriber MAY render multiple summaries 309 which correspond to the same account directly to the user, or MAY 310 merge them as described below. 312 If any of the "Messages-Waiting" status lines report "yes", then the 313 merged state is "yes"; otherwise the merged state is "no". 315 The Subscriber MAY merge summary lines in an implementation-specific 316 way if all notifications contain at least one msg-summary line. 318 3.11 Rate of notifications 320 A Notifier MAY choose to hold NOTIFY requests in "quarantine" for a 321 short administrator-defined period (seconds or minutes) when the 322 message status is changing rapidly. Requests in the quarantine which 323 become invalid are replaced by newer notifications, thus reducing the 324 total volume of notifications. This behavior is encouraged for 325 implementations with heavy interactive use. Note that timely 326 notification which results in a change of overall state (messages 327 waiting or not), and notification of newly added messages is probably 328 more significant to the end user than a notification of newly deleted 329 messages which do not affect the overall message waiting state (e.g. 330 there are still new messages). 332 Notifiers SHOULD NOT generate NOTIFY requests more frequently than 333 once per second. 335 3.12 State Agents 337 A Subscriber MAY use an "alias" or "group" in the Request-URI of a 338 subscription if that name is significant to the messaging system. 339 Implementers MAY create a service which consolidates and summarizes 340 NOTIFYs from many Contacts. This document does not preclude 341 implementations from building state agents which support this event 342 package. 344 3.13 Behavior of a Proxy Server 346 There are no additional requirements on a SIP Proxy, other than to 347 transparently forward the SUBSCRIBE and NOTIFY methods as required in 348 SIP. However, Proxies SHOULD allow non-SIP URLs. Proxies and 349 Redirect servers SHOULD be able to direct the SUBSCRIBE request to an 350 appropriate messaging server User Agent. Proxies are encouraged to 351 support routing to Contacts based on the the method of the request 352 and the existence of a feature="voice-mail" parameter in an 353 Accept-Contact header (as specified in the caller preferences 354 specification). 356 4. Examples of Usage 358 4.1 Example Message Flow 360 The examples shown below are for informational purposes only. For a 361 normative description of the event package, please see sections 3 and 362 5 of this document. 364 In the example call flow below, Alice's IP phone subscribes to the 365 status of Alice's messages. Via headers are omitted for clarity. 367 Subscriber Notifier 368 | | 369 | A1: SUBSCRIBE (new) | 370 |---------------------->| 371 | A2: 200 OK | 372 |<----------------------| 373 | | 374 | A3: NOTIFY (sync) | 375 |<----------------------| 376 | A4: 200 OK | 377 |---------------------->| 378 | | 379 | | 380 | A5: NOTIFY (change) | 381 |<----------------------| 382 | A6: 200 OK | 383 |---------------------->| 384 | | 385 | | 386 | A7: (re)SUBSCRIBE | 387 |---------------------->| 388 | A8: 200 OK | 389 |<----------------------| 390 | | 391 | A9: NOTIFY (sync) | 392 |<----------------------| 393 | A10: 200 OK | 394 |---------------------->| 395 | | 396 | | 397 | A11: (un)SUBSCRIBE | 398 |---------------------->| 399 | A12: 200 OK | 400 |<----------------------| 401 | | 402 | A13: NOTIFY (sync) | 403 |<----------------------| 404 | A14: 200 OK | 405 |---------------------->| 407 A1: Subscriber (Alice's phone) -> 408 Notifier (Alice's voicemail gateway) 409 Subscribe to Alice's message summary status for 1 day. 411 SUBSCRIBE sip:alice@vmail.example.com SIP/2.0 412 To: 413 From: ;tag=78923 414 Date: Mon, 10 Jul 2000 03:55:06 GMT 415 Call-Id: 1349882@alice-phone.example.com 416 CSeq: 4 SUBSCRIBE 417 Contact: 418 Event: message-summary 419 Expires: 86400 420 Accept: application/simple-message-summary 421 Content-Length: 0 423 A2: Notifier -> Subscriber 425 SIP/2.0 200 OK 426 To: ;tag=4442 427 From: ;tag=78923 428 Date: Mon, 10 Jul 2000 03:55:07 GMT 429 Call-Id: 1349882@alice-phone.example.com 430 CSeq: 4 SUBSCRIBE 431 Expires: 86400 432 Content-Length: 0 434 A3: Notifier -> Subscriber 435 (immediate synchronization of current state: 436 2 new and 8 old [2 urgent] messages) 438 NOTIFY sip:alice@alice-phone.example.com SIP/2.0 439 To: ;tag=78923 440 From: ;tag=4442 441 Date: Mon, 10 Jul 2000 03:55:07 GMT 442 Call-Id: 1349882@alice-phone.example.com 443 CSeq: 20 NOTIFY 444 Contact: 445 Event: message-summary 446 Subscription-State: active 447 Content-Type: application/simple-message-summary 448 Content-Length: 99 450 Messages-Waiting: yes 451 Message-Account: sip:alice@vmail.example.com 452 Voice-Message: 2/8 (0/2) 454 A4: Subscriber -> Notifier 456 SIP/2.0 200 OK 457 To: ;tag=78923 458 From: ;tag=4442 459 Date: Mon, 10 Jul 2000 03:55:08 GMT 460 Call-Id: 1349882@alice-phone.example.com 461 CSeq: 20 NOTIFY 462 Content-Length: 0 464 A5: Notifier -> Subscriber 465 This is a notification of new messages. 467 Some headers from each of the new messages are appended. 469 NOTIFY sip:alice@alice-phone.example.com SIP/2.0 470 To: ;tag=78923 471 From: ;tag=4442 472 Date: Mon, 10 Jul 2000 04:28:53 GMT 473 Contact: 474 Call-ID: 1349882@alice-phone.example.com 475 CSeq: 31 NOTIFY 476 Event: message-summary 477 Subscription-State: active 478 Content-Type: application/simple-message-summary 479 Content-Length: 503 481 Messages-Waiting: yes 482 Message-Account: sip:alice@vmail.example.com 483 Voice-Message: 4/8 (1/2) 485 To: 486 From: 487 Subject: carpool tomorrow? 488 Date: Sun, 09 Jul 2000 21:23:01 -0700 489 Priority: normal 490 Message-ID: 13784434989@vmail.example.com 492 To: 493 From: 494 Subject: HELP! at home ill, present for me please 495 Date: Sun, 09 Jul 2000 21:25:12 -0700 496 Priority: urgent 497 Message-ID: 13684434990@vmail.example.com 499 A6: Subscriber -> Notifier 501 SIP/2.0 200 OK 502 To: ;tag=78923 503 From: ;tag=4442 504 Date: Mon, 10 Jul 2000 04:28:53 GMT 505 Call-ID: 1349882@alice-phone.example.com 506 CSeq: 31 NOTIFY 507 Content-Length: 0 509 A7: Subscriber -> Notifier 510 Refresh subscription. 512 SUBSCRIBE sip:alice@vmail.example.com SIP/2.0 513 To: ;tag=4442 514 From: ;tag=78923 515 Date: Mon, 10 Jul 2000 15:55:06 GMT 516 Call-Id: 1349882@alice-phone.example.com 517 CSeq: 8 SUBSCRIBE 518 Contact: 519 Event: message-summary 520 Expires: 86400 521 Accept: application/simple-message-summary 522 Content-Length: 0 524 A8: Notifier -> Subscriber 526 SIP/2.0 200 OK 527 To: ;tag=4442 528 From: ;tag=78923 529 Date: Mon, 10 Jul 2000 15:55:07 GMT 530 Call-Id: 1349882@alice-phone.example.com 531 CSeq: 8 SUBSCRIBE 532 Contact: 533 Expires: 86400 534 Content-Length: 0 536 A9: Notifier -> Subscriber 537 (immediate synchronization of current state) 539 NOTIFY sip:alice@alice-phone.example.com SIP/2.0 540 To: ;tag=78923 541 From: ;tag=4442 542 Date: Mon, 10 Jul 2000 15:55:07 GMT 543 Call-Id: 1349882@alice-phone.example.com 544 CSeq: 47 NOTIFY 545 Contact: 546 Event: message-summary 547 Subscription-State: active 548 Content-Type: application/simple-message-summary 549 Content-Length: 99 551 Messages-Waiting: yes 552 Message-Account: sip:alice@vmail.example.com 553 Voice-Message: 4/8 (1/2) 555 A10: Subscriber -> Notifier 557 SIP/2.0 200 OK 558 To: ;tag=78923 559 From: ;tag=4442 560 Date: Mon, 10 Jul 2000 15:55:08 GMT 561 Call-Id: 1349882@alice-phone.example.com 562 CSeq: 47 NOTIFY 563 Contact: 565 A11: Subscriber -> Notifier 566 Un-subscribe after "alice" logs out. 568 SUBSCRIBE sip:alice@vmail.example.com SIP/2.0 569 To: ;tag=4442 570 From: ;tag=78923 571 Date: Mon, 10 Jul 2000 19:35:06 GMT 572 Call-Id: 1349882@alice-phone.example.com 573 CSeq: 17 SUBSCRIBE 574 Contact: 575 Event: message-summary 576 Expires: 0 577 Accept: application/simple-message-summary 578 Content-Length: 0 580 A12: Notifier -> Subscriber 582 SIP/2.0 200 OK 583 To: ;tag=4442 584 From: ;tag=78923 585 Date: Mon, 10 Jul 2000 19:35:07 GMT 586 Call-Id: 1349882@alice-phone.example.com 587 CSeq: 17 SUBSCRIBE 588 Contact: 589 Expires: 0 590 Content-Length: 0 592 A13: Notifier -> Subscriber 593 (immediate synchronization of current state, 594 which the subscriber can now ignore) 596 NOTIFY sip:alice@alice-phone.example.com SIP/2.0 597 To: ;tag=78923 598 From: ;tag=4442 599 Date: Mon, 10 Jul 2000 19:35:07 GMT 600 Call-Id: 1349882@alice-phone.example.com 601 CSeq: 56 NOTIFY 602 Contact: 603 Event: message-summary 604 Subscription-State: terminated;reason=timeout 605 Content-Type: application/simple-message-summary 606 Content-Length: 99 608 Messages-Waiting: yes 609 Message-Account: sip:alice@vmail.example.com 610 Voice-Message: 4/8 (1/2) 612 A10: Subscriber -> Notifier 614 SIP/2.0 200 OK 615 To: ;tag=78923 616 From: ;tag=4442 617 Date: Mon, 10 Jul 2000 19:35:08 GMT 618 Call-Id: 1349882@alice-phone.example.com 619 CSeq: 56 NOTIFY 620 Event: message-summary 621 Content-Length: 0 623 4.2 Example Usage with Caller Preferences 625 The use of caller preferences is optional but encouraged. If caller 626 preferences is used, a messaging server MAY REGISTER a Contact with 627 an appropriate methods and events tag as shown in the example below. 628 To further distinguish itself, the messaging server MAY also REGISTER 629 as a Contact with the feature="voice-mail" tag. An example of this 630 kind of registration follows below. 632 REGISTER sip:sip3-sj.example.com SIP/2.0 633 To: 634 From: ;tag=4442 635 ... 636 Contact: 637 ;feature="voice-mail";methods="SUBSCRIBE" 638 ;events="message-summary" 640 The following SUBSCRIBE message would find the Contact which 641 registered in the example above. 643 SUSBCRIBE sip:alice@example.com SIP/2.0 644 ... 645 Accept: application/simple-message-summary 646 Event: message-summary 647 Accept-Contact: *;feature="voice-mail" 649 5. Formal Syntax 651 The following syntax specification uses the augmented Backus-Naur 652 Form (BNF) as described in RFC-2234 [5]. 654 5.1 New event-package definition 655 This document defines a new event-package with the package name: 657 message-summary 659 5.2 Body Format Syntax 661 The formal syntax for application/simple-message-summary is below: 663 messsage-summary = msg-status-line CRLF 664 [msg-account CRLF] 665 [*(msg-summary-line CRLF)] 666 [ *opt-msg-headers ] 668 msg-status-line = "Messages-Waiting" HCOLON msg-status 669 msg-status = "yes" / "no" 670 msg-account = "Message-Account" HCOLON Account-URI 671 Account-URI = SIP-URI / SIPS-URI / absoluteURI 673 msg-summary-line = message-context-class HCOLON newmsgs SLASH oldmsgs 674 [ LPAREN new-urgentmsgs SLASH old-urgentmsgs RPAREN ] 676 opt-msg-headers = CRLF 1*(extension-header CRLF) 678 newmsgs = msgcount 679 oldmsgs = msgcount 680 new-urgentmsgs = msgcount 681 old-urgentmsgs = msgcount 682 msgcount = 1*DIGIT ; MUST NOT exceed 2^32-1 684 6. Security Considerations 686 Message Summaries and optional message bodies contain information 687 which is typically very privacy sensitive. At minimum, subscriptions 688 to this event package SHOULD be authenticated and properly 689 authorized. Furthermore, notifications SHOULD be encrypted and 690 integrity protected using either end-to-end mechanisms, or the 691 hop-by-hop protection afforded messages sent to SIPS URIs. 693 Additional security considerations are covered in SIP [1] and SIP 694 Events [2]. 696 7. IANA Considerations 697 7.1 SIP Event Package Registration for message-summary 699 Package name: message-summary 701 Type: package 703 Contact: [Mahy] 705 Published Specification: This document. 707 7.2 MIME Registration for application/simple-message-summary 709 MIME media type name: application 711 MIME subtype name: simple-message-summary 713 Required parameters: none. 715 Optional parameters: none. 717 Encoding considerations: This type is only defined for transfer 718 via SIP [1]. 720 Security considerations: See the "Security Considerations" 721 section in this document. 723 Interoperability considerations: none 725 Published specification: This document. 727 Applications which use this media: The simple-message-summary 728 application subtype supports the exchange of message waiting and 729 message summary information in SIP networks. 731 Additional information: 733 1. Magic number(s): N/A 735 2. File extension(s): N/A 737 3. Macintosh file type code: N/A 739 8. Revision history 740 8.1 Open Issues 742 1. Need to update the caller-preference section to reflect whatever 743 the replacement will be for feature="voice-mail". 745 2. Would be nice to add a pointer to the "collections" work 747 8.2 Changes from draft-ietf-sipping-mwi-00 749 1. Replaced the "media types" concept with message contexts. This is 750 a better semantic match than what was in the draft before, and 751 also controls extensibility and change control in a single 752 document. The list of valid message-context-classes are 753 voice-message, fax-message, pager-message, multimedia-message, 754 text-message, and none. 756 2. Completely updated the syntax to follow that of SIP instead of 757 the previously more restrictive (and somewhat arbitrary) syntax. 758 The SIP syntax adds line folding, for example. The optional 759 message-headers borrow the "extension-header" syntax and explicit 760 whitespace separators defined in SIP (ex: HCOLON, SLASH). 762 3. Added a Message-Account field in the body format to provide the 763 specific account name which corresponds to the notification when 764 forking or state agents are used with group aliases (or 765 collections). 767 4. Changed caller preferences example to exclude methods="SUBSCRIBE" 768 in the SUBSCRIBE request (removed redundant information). 770 5. Changed examples to be consistent with IESG recommendations 772 8.3 Changes from draft-mahy-sipping-mwi-00 774 1. Updated references and split into normative and informational 776 2. Removed normative behavior now specified in Events 778 3. Updated to address the event package sections now specified in 779 Events. 781 4. Added the Subscription-State header field to the examples and 782 removed the Event header field from responses. 784 5. Removed redundant BNF 785 6. Simplified text on how to choose the media type. For Internet 786 Mail, this now references the Message-Context header. 788 8.4 Changes from draft-mahy-sip-mwi-01 790 1. This document is now formatted as a SIP Event Package as defined 791 in Section 4 of RFC 3265 (SIP Events) [2]. 793 2. The event-package name is now "message-summary", to allow for 794 other bodies to extend the package. 796 3. The "urgent" token was missing from the BNF. 798 8.5 Changes from draft-mahy-sip-mwi-00 800 This draft greatly simplifies and shortens the -00 version. 802 1. The generic behavior of SUBSCRIBE/NOTIFY is now greatly clarified 803 in SIP Events [2] and made consistent with PINT and SIP for 804 presence. This message waiting draft is now consistent with SIP 805 Events. 807 2. The XML format has been removed due to lack of immediate 808 interest. At a future date, similar functionality may be added 809 as another body definition with an appropriate MIME type. 811 3. An IANA Considerations section was added to register the new 812 "application/simple-message-summary" MIME type and the 813 "simple-message-summary" SIP event package. 815 4. The "flag-list" was removed due to lack of interest and to 816 encourage simplicity. 818 5. Due to synchronization issues, and the recommendation of the VPIM 819 Working Group, support for message count "deltas" was removed. 821 6. The Messages-Waiting line in the body is now mandatory. 823 7. This version of the draft clarifies the role of caller 824 preferences as optional but encouraged. 826 8. A set of SMTP-like headers from the triggering messages may now 827 optionally follow the message summaries, provided that the 828 resulting NOTIFY on UDP fits in a single datagram. 830 9. Contributors 832 Ilya Slain came up with the initial format of the text body contained 833 in this document. He was previously listed as a co-author, however, 834 he is no longer reachable. 836 10. Acknowledgments 838 Thanks to Dan Wing, Dave Oran, Bill Foster, Steve Levy, Denise 839 Caballero-McCann, Jeff Michel, Priti Patil, Satyender Khatter, Bich 840 Nguyen, Manoj Bhatia, David Williams, and Bryan Byerly of Cisco; 841 Jonathan Rosenberg and Adam Roach of Dynamicsoft; Eric Burger of 842 Snowshore; and Eric Tremblay of Mediatrix. 844 Normative References 846 [1] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., 847 Peterson, J., Sparks, R., Handley, M. and E. Schooler, "SIP: 848 Session Initiation Protocol", RFC 3261, June 2002. 850 [2] Roach, A., "Session Initiation Protocol (SIP)-Specific Event 851 Notification", RFC 3265, June 2002. 853 [3] Bradner, S., "Key words for use in RFCs to Indicate Requirement 854 Levels", BCP 14, RFC 2119, March 1997. 856 [4] Rosenberg, J. and H. Schulzrinne, "Session Initiation Protocol 857 (SIP) Caller Preferences and Callee Capabilities", 858 draft-ietf-sip-callerprefs-07 (work in progress), November 2002. 860 [5] Crocker, D. and P. Overell, "Augmented BNF for Syntax 861 Specifications: ABNF", RFC 2234, November 1997. 863 [6] Burger, E., Candell, E., Eliot, C. and G. Klyne, "Message 864 Context for Internet Mail", RFC 3458, January 2003. 866 Informational References 868 [7] Vaudreuil, G. and G. Parsons, "Voice Profile for Internet Mail 869 - version 2", RFC 2421, September 1998. 871 [8] Freed, N. and N. Borenstein, "Multipurpose Internet Mail 872 Extensions (MIME) Part Two: Media Types", RFC 2046, November 873 1996. 875 [9] Resnick, P., "Internet Message Format", RFC 2822, April 2001. 877 [10] Telcordia, "GR-506: Signaling for Analog Interfaces, Issue 1, 878 Revision 1", Nov 1996. 880 Author's Address 882 Rohan Mahy 883 Cisco Systems, Inc. 884 101 Cooper Street 885 Santa Cruz, CA 95060 886 USA 888 EMail: rohan@cisco.com 890 Intellectual Property Statement 892 The IETF takes no position regarding the validity or scope of any 893 intellectual property or other rights that might be claimed to 894 pertain to the implementation or use of the technology described in 895 this document or the extent to which any license under such rights 896 might or might not be available; neither does it represent that it 897 has made any effort to identify any such rights. 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