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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 ECRIT B. Rosen 3 Internet-Draft NeuStar, Inc. 4 Intended status: Standards Track H. Schulzrinne 5 Expires: January 16, 2014 Columbia U. 6 H. Tschofenig 7 Nokia Siemens Networks 8 July 15, 2013 10 Data-Only Emergency Calls 11 draft-ietf-ecrit-data-only-ea-06.txt 13 Abstract 15 RFC 6443 'Framework for Emergency Calling Using Internet Multimedia' 16 describes how devices use the Internet to place emergency calls and 17 how Public Safety Answering Points (PSAPs) can handle Internet 18 multimedia emergency calls natively. The exchange of multimedia 19 traffic typically involves a SIP session establishment starting with 20 a SIP INVITE that negotiates various parameters for that session. 22 In some cases, however, the transmission of application data is 23 everything that is needed. Examples of such environments include a 24 temperature sensors issuing alerts, or vehicles sending crash data. 25 Often these alerts are conveyed as one-shot data transmissions. 26 These type of interactions are called 'data-only emergency calls'. 27 This document describes a container for the data based on the Common 28 Alerting Protocol (CAP) and its transmission using the SIP MESSAGE 29 transaction. 31 Status of This Memo 33 This Internet-Draft is submitted in full conformance with the 34 provisions of BCP 78 and BCP 79. 36 Internet-Drafts are working documents of the Internet Engineering 37 Task Force (IETF). Note that other groups may also distribute 38 working documents as Internet-Drafts. The list of current Internet- 39 Drafts is at http://datatracker.ietf.org/drafts/current/. 41 Internet-Drafts are draft documents valid for a maximum of six months 42 and may be updated, replaced, or obsoleted by other documents at any 43 time. It is inappropriate to use Internet-Drafts as reference 44 material or to cite them other than as "work in progress." 46 This Internet-Draft will expire on January 16, 2014. 48 Copyright Notice 50 Copyright (c) 2013 IETF Trust and the persons identified as the 51 document authors. All rights reserved. 53 This document is subject to BCP 78 and the IETF Trust's Legal 54 Provisions Relating to IETF Documents 55 (http://trustee.ietf.org/license-info) in effect on the date of 56 publication of this document. Please review these documents 57 carefully, as they describe your rights and restrictions with respect 58 to this document. Code Components extracted from this document must 59 include Simplified BSD License text as described in Section 4.e of 60 the Trust Legal Provisions and are provided without warranty as 61 described in the Simplified BSD License. 63 Table of Contents 65 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 66 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 67 3. Architectural Overview . . . . . . . . . . . . . . . . . . . 4 68 4. Protocol Specification . . . . . . . . . . . . . . . . . . . 6 69 4.1. CAP Transport . . . . . . . . . . . . . . . . . . . . . . 6 70 4.2. Profiling of the CAP Document Content . . . . . . . . . . 6 71 4.3. Sending a Data-Only Emergency Call . . . . . . . . . . . 7 72 5. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 8 73 5.1. 425 (Bad Alert Message) Response Code . . . . . . . . . . 8 74 5.2. The AlertMsg-Error Header Field . . . . . . . . . . . . . 8 75 6. Updates to the CAP Message . . . . . . . . . . . . . . . . . 10 76 7. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 77 8. Security Considerations . . . . . . . . . . . . . . . . . . . 14 78 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 79 9.1. Registration of the 'application/emergencyCall.cap+xml' 80 MIME type . . . . . . . . . . . . . . . . . . . . . . . . 16 81 9.2. IANA Registration of Additional Data Block . . . . . . . 17 82 9.3. IANA Registration for 425 Response Code . . . . . . . . . 17 83 9.4. IANA Registration of New AlertMsg-Error Header Field . . 18 84 9.5. IANA Registration for the SIP AlertMsg-Error Codes . . . 18 85 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19 86 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 19 87 11.1. Normative References . . . . . . . . . . . . . . . . . . 19 88 11.2. Informative References . . . . . . . . . . . . . . . . . 20 89 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21 91 1. Introduction 93 RFC 6443 [RFC6443] describes how devices use the Internet to place 94 emergency calls and how Public Safety Answering Points (PSAPs) can 95 handle Internet multimedia emergency calls natively. The exchange of 96 multimedia traffic typically involves a SIP session establishment 97 starting with a SIP INVITE that negotiates various parameters for 98 that session. 100 In some cases, however, there is only application data to be conveyed 101 from the end devices to a PSAP or some other intermediary. Examples 102 of such environments includes sensors issuing alerts, or vehicles 103 sending crash data. These messages may be one-shot alerts to 104 emergency authorities and do not require establishment of a session. 105 These type of interactions are called 'data-only emergency calls'. 106 In this document, we use the term "call" so that similarities between 107 full sessions with interactive media can be exploited. 109 Data-only emergency calls are similar to regular emergency calls in 110 the sense that they require the emergency indications, emergency call 111 routing functionality and may even have the same location 112 requirements. However, the communication interaction will not lead 113 to the exchange of interactive media, that is, Real-Time Protocol 114 packets, such as voice, video data or real-time text. 116 The Common Alerting Protocol (CAP) [cap] is a document format for 117 exchanging emergency alerts and public warnings. CAP is mainly used 118 for conveying alerts and warnings between authorities and from 119 authorities to citizen/individuals. This document is concerned with 120 citizen to authority "alerts", where the alert is sent without any 121 interactive media. 123 This document describes a method of including a CAP message in a SIP 124 transaction, either by value (CAP message is in the body of the 125 message, using a CID) or by reference (A URI is included in the 126 message, which when dereferenced returns the CAP message) by defining 127 it as a block of "additional data" as definded in 128 [I-D.ietf-ecrit-additional-data]. The additional data mechanism is 129 also used to send alert specific data beyond that available in the 130 CAP message. 132 2. Terminology 134 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 135 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 136 document are to be interpreted as described in RFC 2119 [RFC2119]. 138 3. Architectural Overview 140 This section illustrates two envisioned usage modes; targeted and 141 location-based emergency alert routing. 143 1. Emergency alerts containing only data are targeted to a 144 intermediary recipient responsible for evaluating the next steps. 145 These steps could include: 147 1. Sending an alert containing only data toward a Public Safety 148 Answering Point (PSAP); 150 2. Establishing a third-party initiated emergency call towards a 151 PSAP that could include audio, video, and data. 153 2. Emergency alerts targeted to a Service URN used for IP-based 154 emergency calls where the recipient is not known to the 155 originator. In this scenario, the alert may contain only data 156 (e.g., a CAP and a PIDF-LO payload in a SIP MESSAGE). 158 Figure 1 shows a deployment variant where a sensor, is pre-configured 159 (using techniques outside the scope of this document) to issue an 160 alert to an aggregator that processes these messages and performs 161 whatever steps are necessary to appropriately react on the alert. 162 For example, a security firm may use different sensor inputs to 163 dispatch their security staff to a building they protect or to 164 initiate a third-party emergency call. 166 +------------+ +------------+ 167 | Sensor | | Aggregator | 168 | | | | 169 +---+--------+ +------+-----+ 170 | | 171 Sensors | 172 trigger | 173 emergency | 174 alert | 175 | MESSAGE with CAP | 176 |----------------------------->| 177 | | 178 | Aggregator 179 | processes 180 | emergency 181 | alert 182 | 200 (OK) | 183 |<-----------------------------| 184 | | 185 | | 187 Figure 1: Targeted Emergency Alert Routing 189 In Figure 2 a scenario is shown whereby the alert is routed using 190 location information and the Service URN. An emergency services 191 routing proxy (ESRP) may use LoST to determine the next hop proxy to 192 route the alert message to. A possible receiver is a PSAP and the 193 recipient of the alert may be call taker. In the generic case, there 194 is very likely no prior relationship between the originator and the 195 receiver, e.g. PSAP. A PSAP, for example, is likely to receive and 196 accept alerts from entities it cannot authorize. This scenario 197 corresponds more to the classical emergency services use case and the 198 description in [RFC6881] is applicable. 200 +-----------+ +----------+ 201 +--------+ | ESRP | | PSAP | 202 | Sensor | | | | | 203 +---+----+ +---+-------+ +---+------+ 204 | | | 205 Sensors | | 206 trigger | | 207 emergency | | 208 alert | | 209 | | | 210 | | | 211 | MESSAGE with CAP | | 212 | (including Service URN, | 213 | such as urn:service:sos) | 214 |------------------->| | 215 | | | 216 | ESRP performs | 217 | emergency alert | 218 | routing | 219 | | MESSAGE with CAP | 220 | | (including identity info) | 221 | |----------------------------->| 222 | | | 223 | | PSAP 224 | | processes 225 | | emergency 226 | | alert 227 | | 200 (OK) | 228 | |<-----------------------------| 229 | | | 230 | 200 (OK) | | 231 |<-------------------| | 232 | | | 233 | | | 235 Figure 2: Location-Based Emergency Alert Routing 237 4. Protocol Specification 239 4.1. CAP Transport 241 A CAP message may be sent on the initial message of any SIP 242 transaction. However, this document only describes specific behavior 243 when used with a SIP MESSAGE transaction for a one-shot, data-only 244 emergency call. Behavior with other transactions is not defined. 246 The CAP message included in a SIP message as an additional-data block 247 [I-D.ietf-ecrit-additional-data]. Accordingly, it is introduced to 248 the SIP message with a Call-Info header with a purpose of 249 "emergencyCall.cap". The header may contain a URI that is used by 250 the recipient (or in some cases, an intermediary) to obtain the CAP 251 message. Alternative, the Call-Info header may contain a Content 252 Indirect url [RFC2392] and the CAP message included in the body of 253 the message. In either case, the CAP message is located in a MIME 254 block. The MIME type is set to 'application/emergencyCall.cap+xml'. 256 If the server does not support the functionality required to fulfill 257 the request then a 501 Not Implemented MUST be returned as specified 258 in RFC 3261 [RFC3261]. This is the appropriate response when a UAS 259 does not recognize the request method and is not capable of 260 supporting it for any user. 262 The 415 Unsupported Media Type error MUST be returned as specified in 263 RFC 3261 [RFC3261] if the server is refusing to service the request 264 because the message body of the request is in a format not supported 265 by the server for the requested method. The server MUST return a 266 list of acceptable formats using the Accept, Accept-Encoding, or 267 Accept-Language header field, depending on the specific problem with 268 the content. 270 4.2. Profiling of the CAP Document Content 272 The usage of CAP MUST conform to the specification provided with 273 [cap]. For the usage with SIP the following additional requirements 274 are imposed: 276 sender: A few sub-categories for putting a value in the 277 element have to be considered: 279 Originator is a SIP entity, Author indication irrelevant: When 280 the alert was created by a SIP-based originator and it is 281 not useful to be explicit about the author of the alert then 282 the element MUST be populated with the SIP URI of 283 the user agent. 285 Originator is a non-SIP entity, Author indication irrelevant: In 286 case that the alert was created by a non-SIP based entity 287 and the identity of this original sender wants to be 288 preserved then this identity MUST be placed into the 289 element. In this category the it is not useful to 290 be explicit about the author of the alert. The specific 291 type of identity being used will depends on the technology 292 being used by the original originator. 294 Author indication relevant: In case the author is different from 295 the actual originator of the message and this distinction 296 should be preserved then the element MUST NOT 297 contain the SIP URI of the user agent. 299 incidents: The element MUST be present. This incident 300 identifier MUST be chosen in such a way that it is unique for a 301 given combination. Note that the 302 element is optional and may not be present. 304 scope: The value of the element MAY be set to "Private" if 305 the alert is not meant for public consumption. The 306 element is, however, not used by this specification since the 307 message routing is performed by SIP and the respective address 308 information is already available in other SIP headers. Populating 309 information twice into different parts of the message may lead to 310 inconsistency. 312 parameter: The element MAY contain additional 313 information specific to the sendor. 315 area: It is RECOMMENDED to omit this element when constructing a 316 message. In case that the CAP message already contained an 317 element then the specified location information SHOULD be copied 318 into the PIDF-LO structure of the 'geolocation' header. 320 4.3. Sending a Data-Only Emergency Call 321 A data-only emergency call is sent using a SIP MESSAGE transaction 322 with a CAP URI or body as described above in a manner similar to how 323 an emergency call with interactive media is sent, as described in 324 [RFC6881]. The MESSAGE transaction does not create a session or send 325 media, but otherwise, the header content of the transaction, routing, 326 and processing of data-only calls are the same as those of other 327 emergency calls. 329 5. Error Handling 331 This section defines a new error response code and a header field for 332 additional information. 334 5.1. 425 (Bad Alert Message) Response Code 336 This SIP extension creates a new location-specific response code, 337 defined as follows, 339 425 (Bad Alert Message) 341 The 425 response code is a rejection of the request due to its 342 included alert content, indicating that it was malformed or not 343 satisfactory for the recipient's purpose. 345 A SIP intermediary can also reject an alert it receives from a UA 346 when it understands that the provided alert is malformed. 348 Section 5.2 describes an AlertMsg-Error header field with more 349 details about what was wrong with the alert message in the request. 350 This header field MUST be included in the 425 response. 352 It is only appropriate to generate a 425 response when the responding 353 entity has no other information in the request that are usable by the 354 responder. 356 A 425 response code MUST NOT be sent in response to a request that 357 lacks an alert message entirely, as the user agent in that case may 358 not support this extension at all. 360 A 425 response is a final response within a transaction, and MUST NOT 361 terminate an existing dialog. 363 5.2. The AlertMsg-Error Header Field 365 The AlertMsg-Error header provides additional information about what 366 was wrong with the original request. In some cases the provided 367 information will be used for debugging purposes. 369 The AlertMsg-Error header field has the following ABNF [RFC5234]: 371 message-header /= AlertMsg-Error 372 ; (message-header from 3261) 373 AlertMsg-Error = "AlertMsg-Error" HCOLON 374 ErrorValue 375 ErrorValue = error-code 376 *(SEMI error-params) 377 error-code = 1*3DIGIT 378 error-params = error-code-text 379 / generic-param ; from RFC3261 380 error-code-text = "code" EQUAL quoted-string ; from RFC3261 382 HCOLON, SEMI, and EQUAL are defined in RFC3261 [RFC3261]. DIGIT is 383 defined in RFC5234 [RFC5234]. 385 The AlertMsg-Error header field MUST contain only one ErrorValue to 386 indicate what was wrong with the alert payload the recipient 387 determined was bad. 389 The ErrorValue contains a 3-digit error code indicating what was 390 wrong with the alert in the request. This error code has a 391 corresponding quoted error text string that is human understandable. 392 The text string are OPTIONAL, but RECOMMENDED for human readability, 393 similar to the string phrase used for SIP response codes. That said, 394 the strings are complete enough for rendering to the user, if so 395 desired. The strings in this document are recommendations, and are 396 not standardized - meaning an operator can change the strings - but 397 MUST NOT change the meaning of the error code. Similar to how RFC 398 3261 specifies, there MUST NOT be more than one string per error 399 code. 401 The AlertMsg-Error header field MAY be included in any response as an 402 alert message was in the request part of the same transaction. For 403 example, a UA includes an alert in an MESSAGE to a PSAP. The PSAP 404 can accept this MESSAGE, thus creating a dialog, even though his UA 405 determined the alert message contained in the MESSAGE was bad. The 406 PSAP merely includes an AlertMsg-Error header value in the 200 OK to 407 the MESSAGE informing the UA that the MESSAGE was accepted but the 408 alert provided was bad. 410 If, on the other hand, the PSAP cannot accept the transaction without 411 a suitable alert message, a 425 response is sent. 413 A SIP intermediary that requires the UA's alert message in order to 414 properly process the transaction may also sends a 425 with a 415 AlertMsg-Error code. 417 This document defines an initial list of error code ranges for any 418 SIP response, including provisional responses (other than 100 Trying) 419 and the new 425 response. There MUST be no more than one AlertMsg- 420 Error code in a SIP response. 422 AlertMsg-Error: 100 ; code="Cannot Process the Alert Payload" 424 AlertMsg-Error: 101 ; code="Alert Payload was not present or could 425 not be found" 427 AlertMsg-Error: 102 ; code="Not enough information to determine the 428 purpose of the alert" 430 AlertMsg-Error: 103 ; code="Alert Payload was corrupted" 432 Additionally, if an entity cannot or chooses not to process the alert 433 message from a SIP request, a 500 (Server Internal Error) SHOULD be 434 used with or without a configurable Retry-After header field. 436 6. Updates to the CAP Message 438 If the sender anticipates that the content of the CAP message may 439 need to be updated during the lifecycle of the event referred to in 440 the message, it may include an update block as defined in 441 [I-D.rosen-ecrit-addldata-subnot]. 443 7. Example 445 Figure 3 shows a CAP document indicating a BURGLARY alert issued by a 446 sensor called 'sensor1@domain.com'. The location of the sensor can 447 be obtained from the attached location information provided via the 448 'geolocation' header contained in the SIP MESSAGE structure. 449 Additionally, the sensor provided some data long with the alert 450 message using proprietary information elements only to be processed 451 by the receiver, a SIP entity acting as an aggregator. This example 452 reflects the description in Figure 1. 454 MESSAGE sip:aggregator@domain.com SIP/2.0 455 Via: SIP/2.0/TCP sensor1.domain.com;branch=z9hG4bK776sgdkse 456 Max-Forwards: 70 457 From: sip:sensor1@domain.com;tag=49583 458 To: sip:aggregator@domain.com 459 Call-ID: asd88asd77a@1.2.3.4 460 Geolocation: 461 ;routing-allowed=yes 462 Supported: geolocation 463 Accept: application/pidf+xml, application/emergencyCall.cap+xml 464 CSeq: 1 MESSAGE 465 Call-Info: cid:abcdef2@domain.com;purpose=emergencyCall.cap 466 Content-Type: multipart/mixed; boundary=boundary1 467 Content-Length: ... 469 --boundary1 471 Content-Type: application/emergencyCall.cap 472 Content-ID: 473 Content-Disposition: by-reference;handling=optional 474 476 477 S-1 478 sip:sensor1@domain.com 479 2008-11-19T14:57:00-07:00 480 Actual 481 Alert 482 Private 483 abc1234 484 485 Security 486 BURGLARY 487 Expected 488 Likely 489 Moderate 490 SENSOR 1 491 492 SENSOR-DATA-NAMESPACE1 493 123 494 495 496 SENSOR-DATA-NAMESPACE2 497 TRUE 498 499 500 502 --boundary1 504 Content-Type: application/pidf+xml 505 Content-ID: 506 Content-Disposition: by-reference;handling=optional 507 508 517 518 519 520 521 522 32.86726 -97.16054 523 524 525 526 527 false 528 529 2010-11-14T20:00:00Z 530 531 532 802.11 533 534 2010-11-04T20:57:29Z 535 536 537 --boundary1-- 539 Figure 3: Example Message conveying an Alert to an Aggregator 541 Figure 4 shows the same CAP document sent as a data-only emergency 542 call towards a PSAP. 544 MESSAGE urn:service:sos SIP/2.0 545 Via: SIP/2.0/TCP sip:aggreg.1.example.com;branch=z9hG4bK776abssa 546 Max-Forwards: 70 547 From: sip:aggregator@example.com;tag=32336 548 To: 112 549 Call-ID: asdf33443a@example.com 550 Route: sip:psap1.example.gov 551 Geolocation: 552 ;routing-allowed=yes 553 Supported: geolocation 554 Accept: application/pidf+xml, application/emergencyCall.cap+xml 555 Call-info: cid:abcdef2@domain.com;purpose=emergencyCall.cap 556 CSeq: 1 MESSAGE 557 Content-Type: multipart/mixed; boundary=boundary1 558 Content-Length: ... 560 --boundary1 562 Content-Type: application/emergencyCall.cap+xml 563 Content-ID: 564 566 567 S-1 568 sip:sensor1@domain.com 569 2008-11-19T14:57:00-07:00 570 Actual 571 Alert 572 Private 573 abc1234 574 575 Security 576 BURGLARY 577 Expected 578 Likely 579 Moderate 580 SENSOR 1 581 582 SENSOR-DATA-NAMESPACE1 583 123 584 585 586 SENSOR-DATA-NAMESPACE2 587 TRUE 588 589 590 592 --boundary1 594 Content-Type: application/pidf+xml 595 Content-ID: 596 597 606 607 608 609 610 611 32.86726 -97.16054 612 613 614 615 616 false 617 618 2010-11-14T20:00:00Z 619 620 621 802.11 622 623 2010-11-04T20:57:29Z 624 625 626 --boundary1-- 628 Figure 4: Example Message conveying an Alert to a PSAP 630 8. Security Considerations 632 This section discusses security considerations when SIP user agents 633 issue emergency alerts utilizing MESSAGE and CAP. Location specific 634 threats are not unique to this document and are discussed in 635 [I-D.ietf-ecrit-trustworthy-location] and [RFC6442]. 637 The ECRIT emergency services architecture [RFC6443] considers 638 classical individual-to-authority emergency calling and the identity 639 of the emergency caller does not play a role at the time of the call 640 establishment itself, i.e., a response to the emergency call will not 641 depend on the identity of the caller. In case of emergency alerts 642 generated by devices, like sensors, the processing may be different 643 in order to reduce the number of falsely generated emergency alerts. 644 Alerts may get triggered based on certain sensor input that may have 645 been caused by other factors than the actual occurrence of an alert 646 relevant event. For example, a sensor may simply be malfunctioning. 647 For this purpose not all alert messages are directly sent to a PSAP 648 but rather may be pre-processed by a separate entity, potentially 649 under supervision by a human, to filter alerts and potentially 650 correlate received alerts with others to obtain a larger picture of 651 the ongoing situation. 653 In any case, for alerts that are initiated by sensors the identity 654 may play an important role in deciding whether to accept or ignore an 655 incoming alert message. With the scenario shown in Figure 1 it is 656 very likely that only authorized sensor input will be processed. For 657 this purpose it needs to be ensured that no alert messages from an 658 unknown origin are accepted. Two types of information elements can 659 be used for this purpose: 661 1. SIP itself provides security mechanisms that allow the 662 verification of the originator's identity. These mechanisms can 663 be re-used, such as P-Asserted-Identity [RFC3325] or SIP Identity 664 [RFC4474]. The latter provides a cryptographic assurance while 665 the former relies on a chain of trust model. 667 2. CAP provides additional security mechanisms and the ability to 668 carry additional information about the sender's identity. 669 Section 3.3.2.1 of [cap] specifies the signing algorithms of CAP 670 documents. 672 In addition to the desire to perform identity-based access control 673 the classical communication security threats need to be considered, 674 including integrity protection to prevent forgery and replay of alert 675 messages in transit. To deal with replay of alerts a CAP document 676 contains the mandatory , , elements and an 677 optional element. These attributes make the CAP document 678 unique for a specific sender and provide time restrictions. An 679 entity that has received a CAP message already within the indicated 680 timeframe is able to detect a replayed message and, if the content of 681 that message is unchanged, then no additional security vulnerability 682 is created. Additionally, it is RECOMMENDED to make use of SIP 683 security mechanisms, such as SIP Identity [RFC4474], to tie the CAP 684 message to the SIP message. To provide protection of the entire SIP 685 message exchange between neighboring SIP entities the usage of TLS is 686 mandatory. 688 Note that none of the security mechanism in this document protect 689 against a compromised sensor sending crafted alerts. 691 9. IANA Considerations 693 9.1. Registration of the 'application/emergencyCall.cap+xml' MIME type 695 To: ietf-types@iana.org 697 Subject: Registration of MIME media type application/ 698 emergencyCall.cap+xml 700 MIME media type name: application 702 MIME subtype name: cap+xml 704 Required parameters: (none) 706 Optional parameters: charset; Indicates the character encoding of 707 enclosed XML. Default is UTF-8 [RFC3629]. 709 Encoding considerations: Uses XML, which can employ 8-bit 710 characters, depending on the character encoding used. See RFC 711 3023 [RFC3023], Section 3.2. 713 Security considerations: This content type is designed to carry 714 payloads of the Common Alerting Protocol (CAP). 716 Interoperability considerations: This content type provides a way to 717 convey CAP payloads. 719 Published specification: RFC XXX [Replace by the RFC number of this 720 specification]. 722 Applications which use this media type: Applications that convey 723 alerts and warnings according to the CAP standard. 725 Additional information: OASIS has published the Common Alerting 726 Protocol at http://www.oasis-open.org/committees/ 727 documents.php&wg_abbrev=emergency 729 Person and email address to contact for further information: Hannes 730 Tschofenig, Hannes.Tschofenig@nsn.com 732 Intended usage: Limited use 734 Author/Change controller: IETF ECRIT working group 736 Other information: This media type is a specialization of 737 application/xml RFC 3023 [RFC3023], and many of the considerations 738 described there also apply to application/cap+xml. 740 9.2. IANA Registration of Additional Data Block 742 This document registers a new block type in the sub-registry called 743 'Additional Data Blocks' defined in [I-D.ietf-ecrit-additional-data]. 744 The token is "cap" and the reference is this document. 746 9.3. IANA Registration for 425 Response Code 748 In the SIP Response Codes registry, the following is added 750 Reference: RFC-XXXX (i.e., this document) 752 Response code: 425 (recommended number to assign) 754 Default reason phrase: Bad Alert Message 756 Registry: 757 Response Code Reference 758 ------------------------------------------ --------- 759 Request Failure 4xx 760 425 Bad Alert Message [this doc] 762 This SIP Response code is defined in Section 5. 764 9.4. IANA Registration of New AlertMsg-Error Header Field 766 The SIP AlertMsg-error header field is created by this document, with 767 its definition and rules in Section 5, to be added to the IANA sip- 768 parameters registry with two actions: 770 1. Update the Header Fields registry with 772 Registry: 773 Header Name compact Reference 774 ----------------- ------- --------- 775 AlertMsg-Error [this doc] 777 2. In the portion titled "Header Field Parameters and Parameter 778 Values", add 780 Predefined 781 Header Field Parameter Name Values Reference 782 ----------------- ------------------- ---------- --------- 783 AlertMsg-Error code yes [this doc] 785 9.5. IANA Registration for the SIP AlertMsg-Error Codes 787 This document creates a new registry for SIP, called "AlertMsg-Error 788 Codes". AlertMsg-Error codes provide reason for the error discovered 789 by recipients, categorized by action to be taken by error recipient. 790 The initial values for this registry are shown below. 792 Registry Name: AlertMsg-Error Codes 794 Reference: [this doc] 796 Registration Procedures: Specification Required 798 Code Default Reason Phrase Reference 799 ---- --------------------------------------------------- --------- 800 100 "Cannot Process the Alert Payload" [this doc] 802 101 "Alert Payload was not present or could not be found" [this doc] 803 102 "Not enough information to determine 804 the purpose of the alert" [this doc] 806 103 "Alert Payload was corrupted" [this doc] 808 Details of these error codes are in Section 5. 810 10. Acknowledgments 812 The authors would like to thank the participants of the Early Warning 813 adhoc meeting at IETF#69 for their feedback. Additionally, we would 814 like to thank the members of the NENA Long Term Direction Working 815 Group for their feedback. 817 Additionally, we would like to thank Martin Thomson, James 818 Winterbottom, Shida Schubert, Bernard Aboba, and Marc Linsner for 819 their review comments. 821 11. References 823 11.1. Normative References 825 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 826 Requirement Levels", March 1997. 828 [cap] Jones, E. and A. Botterell, "Common Alerting Protocol v. 829 1.1 ", October 2005. 831 [RFC2392] Levinson, E., "Content-ID and Message-ID Uniform Resource 832 Locators", RFC 2392, August 1998. 834 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, 835 A., Peterson, J., Sparks, R., Handley, M., and E. 836 Schooler, "SIP: Session Initiation Protocol", RFC 3261, 837 June 2002. 839 [RFC3428] Campbell, B., Rosenberg, J., Schulzrinne, H., Huitema, C., 840 and D. Gurle, "Session Initiation Protocol (SIP) Extension 841 for Instant Messaging", RFC 3428, December 2002. 843 [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax 844 Specifications: ABNF", STD 68, RFC 5234, January 2008. 846 [RFC3903] Niemi, A., "Session Initiation Protocol (SIP) Extension 847 for Event State Publication", RFC 3903, October 2004. 849 [RFC3023] Murata, M., St. Laurent, S., and D. Kohn, "XML Media 850 Types", RFC 3023, January 2001. 852 [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 853 10646", STD 63, RFC 3629, November 2003. 855 [RFC6442] Polk, J., Rosen, B., and J. Peterson, "Location Conveyance 856 for the Session Initiation Protocol", RFC 6442, December 857 2011. 859 [RFC6665] Roach, A., "SIP-Specific Event Notification", RFC 6665, 860 July 2012. 862 [RFC6881] Rosen, B. and J. Polk, "Best Current Practice for 863 Communications Services in Support of Emergency Calling", 864 BCP 181, RFC 6881, March 2013. 866 [I-D.ietf-ecrit-additional-data] 867 Rosen, B., Tschofenig, H., Marshall, R., Randy, R., and J. 868 Winterbottom, "Additional Data related to an Emergency 869 Call", draft-ietf-ecrit-additional-data-10 (work in 870 progress), July 2013. 872 [I-D.rosen-ecrit-addldata-subnot] 873 Rosen, B., "Updating Additional Data related to an 874 Emergency Call using Subscribe/ Notify", draft-rosen- 875 ecrit-addldata-subnot-00 (work in progress), July 2013. 877 11.2. Informative References 879 [I-D.ietf-ecrit-trustworthy-location] 880 Tschofenig, H., Schulzrinne, H., and B. Aboba, 881 "Trustworthy Location", draft-ietf-ecrit-trustworthy- 882 location-06 (work in progress), July 2013. 884 [RFC4474] Peterson, J. and C. Jennings, "Enhancements for 885 Authenticated Identity Management in the Session 886 Initiation Protocol (SIP)", RFC 4474, August 2006. 888 [RFC3325] Jennings, C., Peterson, J., and M. Watson, "Private 889 Extensions to the Session Initiation Protocol (SIP) for 890 Asserted Identity within Trusted Networks", RFC 3325, 891 November 2002. 893 [RFC6443] Rosen, B., Schulzrinne, H., Polk, J., and A. Newton, 894 "Framework for Emergency Calling Using Internet 895 Multimedia", RFC 6443, December 2011. 897 Authors' Addresses 899 Brian Rosen 900 NeuStar, Inc. 901 470 Conrad Dr 902 Mars, PA 16046 903 US 905 Email: br@brianrosen.net 907 Henning Schulzrinne 908 Columbia University 909 Department of Computer Science 910 450 Computer Science Building 911 New York, NY 10027 912 US 914 Phone: +1 212 939 7004 915 Email: hgs+ecrit@cs.columbia.edu 916 URI: http://www.cs.columbia.edu 918 Hannes Tschofenig 919 Nokia Siemens Networks 920 Linnoitustie 6 921 Espoo 02600 922 Finland 924 Phone: +358 (50) 4871445 925 Email: Hannes.Tschofenig@gmx.net 926 URI: http://www.tschofenig.priv.at