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Tschofenig 5 Expires: August 18, 2017 Individual 6 February 14, 2017 8 Next-Generation Pan-European eCall 9 draft-ietf-ecrit-ecall-27.txt 11 Abstract 13 This document describes how to use IP-based emergency services 14 mechanisms to support the next generation of the pan European in- 15 vehicle emergency call service defined under the eSafety initiative 16 of the European Commission (generally referred to as "eCall"). eCall 17 is a standardized and mandated system for a special form of emergency 18 calls placed by vehicles, providing real-time communications and an 19 integrated set of related data. 21 This document also registers MIME media types and an Emergency Call 22 Additional Data Block for the eCall vehicle data and metadata/control 23 data, and an INFO package to enable carrying this data in SIP INFO 24 requests. 26 Although this specification is designed to meet the requirements of 27 European next-generation eCall, it is specified generically such that 28 the technology can be re-used or extended to suit requirements across 29 jurisdictions. 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 August 18, 2017. 48 Copyright Notice 50 Copyright (c) 2017 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. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 66 2. Document Scope . . . . . . . . . . . . . . . . . . . . . . . 4 67 3. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 5 68 4. eCall Requirements . . . . . . . . . . . . . . . . . . . . . 7 69 5. Vehicle Data . . . . . . . . . . . . . . . . . . . . . . . . 7 70 6. Data Transport . . . . . . . . . . . . . . . . . . . . . . . 7 71 7. Call Setup . . . . . . . . . . . . . . . . . . . . . . . . . 10 72 8. Test Calls . . . . . . . . . . . . . . . . . . . . . . . . . 11 73 9. The Metadata/Control Object . . . . . . . . . . . . . . . . . 11 74 9.1. The Control Block . . . . . . . . . . . . . . . . . . . . 13 75 9.1.1. The element . . . . . . . . . . . . . . . . . . 13 76 9.1.1.1. Attributes of the element . . . . . . . . . 14 77 9.1.1.2. Child Element of the element . . . . . . . 14 78 9.1.1.3. Ack Examples . . . . . . . . . . . . . . . . . . 15 79 9.1.2. The element . . . . . . . . . . . . . 15 80 9.1.2.1. Child Element of the element . . . 15 81 9.1.2.2. Capabilities Example . . . . . . . . . . . . . . 16 82 9.1.3. The element . . . . . . . . . . . . . . . . 16 83 9.1.3.1. Attributes of the element . . . . . . . 17 84 9.1.3.2. Request Example . . . . . . . . . . . . . . . . . 18 85 10. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 18 86 11. Security Considerations . . . . . . . . . . . . . . . . . . . 24 87 12. Privacy Considerations . . . . . . . . . . . . . . . . . . . 25 88 13. XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . 26 89 14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28 90 14.1. The EmergencyCallData Media Subtree . . . . . . . . . . 28 91 14.2. Service URN Registrations . . . . . . . . . . . . . . . 29 92 14.3. MIME Media Type Registration for 93 'application/emergencyCallData.eCall.MSD' . . . . . . . 29 94 14.4. MIME Media Type Registration for 95 'application/emergencyCallData.control+xml' . . . . . . 31 97 14.5. Registration of the 'eCall.MSD' entry in the Emergency 98 Call Additional Data Types registry . . . . . . . . . . 32 99 14.6. Registration of the 'control' entry in the Emergency 100 Call Additional Data Types registry . . . . . . . . . . 32 101 14.7. Registration for 102 urn:ietf:params:xml:ns:EmergencyCallData:control . . . . 33 103 14.8. Registry Creation . . . . . . . . . . . . . . . . . . . 33 104 14.8.1. Emergency Call Action Registry . . . . . . . . . . . 33 105 14.8.2. Emergency Call Action Failure Reason Registry . . . 34 106 14.9. The emergencyCallData.eCall.MSD INFO package . . . . . . 35 107 14.9.1. Overall Description . . . . . . . . . . . . . . . . 35 108 14.9.2. Applicability . . . . . . . . . . . . . . . . . . . 36 109 14.9.3. Info Package Name . . . . . . . . . . . . . . . . . 36 110 14.9.4. Info Package Parameters . . . . . . . . . . . . . . 36 111 14.9.5. SIP Option-Tags . . . . . . . . . . . . . . . . . . 37 112 14.9.6. INFO Request Body Parts . . . . . . . . . . . . . . 37 113 14.9.7. Info Package Usage Restrictions . . . . . . . . . . 37 114 14.9.8. Rate of INFO Requests . . . . . . . . . . . . . . . 37 115 14.9.9. Info Package Security Considerations . . . . . . . . 38 116 14.9.10. Implementation Details . . . . . . . . . . . . . . . 38 117 14.9.11. Examples . . . . . . . . . . . . . . . . . . . . . . 38 118 15. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 38 119 16. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 38 120 17. Changes from Previous Versions . . . . . . . . . . . . . . . 38 121 17.1. Changes from draft-ietf-19 to draft-ietf-20 . . . . . . 38 122 17.2. Changes from draft-ietf-18 to draft-ietf-19 . . . . . . 39 123 17.3. Changes from draft-ietf-17 to draft-ietf-18 . . . . . . 39 124 17.4. Changes from draft-ietf-16 to draft-ietf-17 . . . . . . 39 125 17.5. Changes from draft-ietf-15 to draft-ietf-16 . . . . . . 39 126 17.6. Changes from draft-ietf-14 to draft-ietf-15 . . . . . . 39 127 17.7. Changes from draft-ietf-13 to draft-ietf-14 . . . . . . 39 128 17.8. Changes from draft-ietf-12 to draft-ietf-13 . . . . . . 39 129 17.9. Changes from draft-ietf-11 to draft-ietf-12 . . . . . . 40 130 17.10. Changes from draft-ietf-09 to draft-ietf-11 . . . . . . 40 131 17.11. Changes from draft-ietf-08 to draft-ietf-09 . . . . . . 40 132 17.12. Changes from draft-ietf-07 to draft-ietf-08 . . . . . . 40 133 17.13. Changes from draft-ietf-06 to draft-ietf-07 . . . . . . 41 134 17.14. Changes from draft-ietf-05 to draft-ietf-06 . . . . . . 41 135 17.15. Changes from draft-ietf-04 to draft-ietf-05 . . . . . . 41 136 17.16. Changes from draft-ietf-03 to draft-ietf-04 . . . . . . 41 137 17.17. Changes from draft-ietf-02 to draft-ietf-03 . . . . . . 41 138 17.18. Changes from draft-ietf-01 to draft-ietf-02 . . . . . . 42 139 17.19. Changes from draft-ietf-00 to draft-ietf-01 . . . . . . 42 140 17.20. Changes from draft-gellens-03 to draft-ietf-00 . . . . . 42 141 17.21. Changes from draft-gellens-02 to -03 . . . . . . . . . . 42 142 17.22. Changes from draft-gellens-01 to -02 . . . . . . . . . . 43 143 17.23. Changes from draft-gellens-00 to -01 . . . . . . . . . . 43 144 18. References . . . . . . . . . . . . . . . . . . . . . . . . . 43 145 18.1. Normative References . . . . . . . . . . . . . . . . . . 43 146 18.2. Informative references . . . . . . . . . . . . . . . . . 44 147 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 46 149 1. Terminology 151 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 152 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 153 document are to be interpreted as described in [RFC2119]. 155 This document re-uses terminology defined in Section 3 of [RFC5012]. 157 Additionally, we use the following abbreviations: 159 +--------+----------------------------------------+ 160 | Term | Expansion | 161 +--------+----------------------------------------+ 162 | 3GPP | 3rd Generation Partnership Project | 163 | | | 164 | CEN | European Committee for Standardization | 165 | | | 166 | EENA | European Emergency Number Association | 167 | | | 168 | ESInet | Emergency Services IP network | 169 | | | 170 | IMS | IP Multimedia Subsystem | 171 | | | 172 | IVS | In-Vehicle System | 173 | | | 174 | MNO | Mobile Network Operator | 175 | | | 176 | MSD | Minimum Set of Data | 177 | | | 178 | PSAP | Public Safety Answering Point | 179 +--------+----------------------------------------+ 181 2. Document Scope 183 This document is focused on the signaling, data exchange, and 184 protocol needs of next-generation eCall (NG-eCall, also referred to 185 as packet-switched eCall or all-IP eCall) within the SIP framework 186 for emergency calls (as described in [RFC6443] and [RFC6881]). eCall 187 itself is specified by 3GPP (3rd Generation Partnership Project) and 188 CEN (European Committee for Standardization) and these specifications 189 include far greater scope than is covered here. 191 The eCall service operates over cellular wireless communication, but 192 this document does not address cellular-specific details, nor client 193 domain selection (e.g., circuit-switched versus packet-switched). 194 All such aspects are the purview of their respective standards 195 bodies. The scope of this document is limited to eCall operating 196 within a SIP-based environment (e.g., 3GPP IMS Emergency Calling 197 [TS23.167]). 199 Although this specification is designed to meet the requirements of 200 pan-European next-generation eCall, it is specified generically such 201 that the technology can be re-used or extended to suit requirements 202 across jurisdictions (see, e.g., [I-D.ietf-ecrit-car-crash]), and 203 extension points are provided to facilitate this. 205 Note that vehicles designed for multiple regions might need to 206 support eCall and other Advanced Automatic Crash Notification (AACN) 207 systems (such as described in [I-D.ietf-ecrit-car-crash]), but this 208 is out of scope of this document. 210 3. Introduction 212 Emergency calls made from vehicles (e.g., in the event of a crash) 213 assist in significantly reducing road deaths and injuries by allowing 214 emergency services to be aware of the incident, the state of the 215 vehicle, the location of the vehicle, and to have a voice channel 216 with the vehicle occupants. This enables a quick and appropriate 217 response. 219 The European Commission initiative of eCall was conceived in the late 220 1990s, and has evolved to a European Parliament decision requiring 221 the implementation of a compliant in-vehicle system (IVS) in new 222 vehicles and the deployment of eCall in the European Member States in 223 the very near future. Other regions are developing eCall-compatible 224 systems. 226 The pan-European eCall system is a standardized and mandated 227 mechanism for emergency calls by vehicles, providing a voice channel 228 and transmission of data. eCall establishes procedures for such 229 calls to be placed by in-vehicle systems, recognized and processed by 230 the mobile network, and routed to a specialized PSAP where the 231 vehicle data is available to assist the call taker in assessing and 232 responding to the situation. eCall provides a standard set of 233 vehicle, sensor (e.g., crash related), and location data. 235 An eCall can be either user-initiated or automatically triggered. 236 Automatically triggered eCalls indicate a car crash or some other 237 serious incident. Manually triggered eCalls might be reports of 238 witnessed crashes or serious hazards. PSAPs might apply specific 239 operational handling to manual and automatic eCalls. 241 Legacy eCall is standardized (by 3GPP [SDO-3GPP] and CEN [CEN]) as a 242 3GPP circuit-switched call over GSM (2G) or UMTS (3G). Flags in the 243 call setup mark the call as an eCall, and further indicate if the 244 call was automatically or manually triggered. The call is routed to 245 an eCall-capable PSAP, a voice channel is established between the 246 vehicle and the PSAP, and an eCall in-band modem is used to carry a 247 defined set of vehicle, sensor (e.g., crash related), and location 248 data (the Minimum Set of Data or MSD) within the voice channel. The 249 same in-band mechanism is used for the PSAP to acknowledge successful 250 receipt of the MSD, and to request the vehicle to send a new MSD 251 (e.g., to check if the state of or location of the vehicle or its 252 occupants has changed). NG-eCall moves from circuit switched to all- 253 IP, and carries the vehicle data and eCall signaling as additional 254 data carried with the call. This document describes how IETF 255 mechanisms for IP-based emergency calls (including [RFC6443] and 256 [RFC7852]) are used to provide the signaling and data exchange of the 257 next generation of pan-European eCall. 259 The European Telecommunications Standards Institute (ETSI) [SDO-ETSI] 260 has published a Technical Report titled "Mobile Standards Group 261 (MSG); eCall for VoIP" [MSG_TR] that presents findings and 262 recommendations regarding support for eCall in an all-IP environment. 263 The recommendations include the use of 3GPP IMS emergency calling 264 with additional elements identifying the call as an eCall and as 265 carrying eCall data and with mechanisms for carrying the data and 266 eCall signaling. 3GPP IMS emergency services support multimedia, 267 providing the ability to carry voice, text, and video. This 268 capability is referred to within 3GPP as Multimedia Emergency 269 Services (MMES). 271 A transition period will exist during which time the various entities 272 involved in initiating and handling an eCall might support next- 273 generation eCall, legacy eCall, or both. The issues of migration and 274 co-existence during the transition period are outside the scope of 275 this document. 277 This document indicates how to use IP-based emergency services 278 mechanisms to support next-generation eCall. 280 This document also registers MIME media types and an Emergency Call 281 Additional Data Block for the eCall vehicle data (MSD) and metadata/ 282 control data, and an INFO package to enable carrying this data in SIP 283 INFO requests. 285 The MSD is carried in the MIME type 'application/ 286 emergencyCallData.eCall.MSD' and the metadata/control block is 287 carried in the MIME type 'application/emergencyCallData.control+xml' 288 (both of which are registered in Section 14). An INFO package is 289 defined (in Section 14.9) to enable these MIME types to be carried in 290 SIP INFO requests, per [RFC6086]. 292 4. eCall Requirements 294 eCall requirements are specified by CEN in [EN_16072] and by 3GPP in 295 [TS22.101] clauses 10.7 and A.27 and [TS24.229] section 4.7.6. 296 Requirements specific to vehicle data are contained in EN 15722 297 [msd]. 299 5. Vehicle Data 301 Pan-European eCall provides a standardized and mandated set of 302 vehicle related data (including VIN, vehicle type, propulsion type, 303 current and optionally previous location coordinates, and number of 304 occupants), known as the Minimum Set of Data (MSD). The European 305 Committee for Standardization (CEN) has specified this data in EN 306 15722 [msd], along with both ASN.1 and XML encodings. Both circuit- 307 switched eCall and this document use the ASN.1 PER encoding, which is 308 specified in Annex A of EN 15722 [msd] (the XML encoding specified in 309 Annex C is not used in this document, per 3GPP [SDO-3GPP]). 311 This document registers the 'application/emergencyCallData.eCall.MSD' 312 MIME media type to enable the MSD to be carried in SIP. As an ASN.1 313 PER encoded object, the data is binary and transported using binary 314 content transfer encoding within SIP messages. This document also 315 adds the 'eCall.MSD' entry to the Emergency Call Additional Data 316 Types registry to enable the MSD to be recognized as such in a SIP- 317 based eCall emergency call. (See [RFC7852] for more information 318 about the registry and how it is used.) 320 See Section 6 for a discussion of how the MSD vehicle data is 321 conveyed in an NG-eCall. 323 6. Data Transport 325 [RFC7852] establishes a general mechanism for conveying blocks of 326 data within a SIP emergency call. This document makes use of that 327 mechanism to include vehicle data (the MSD, see Section 5) and/or 328 metadata/control information (see Section 9) within SIP messages. 329 This document also registers an INFO package (in Section 14.9) to 330 enable eCall related data blocks to be carried in SIP INFO requests 331 (per [RFC6086], new INFO usages require the definition of an INFO 332 package). 334 Note that if other data sets need to be transmitted in the future, 335 the appropriate signalling mechanism for such data needs to be 336 evaluated, including factors such as the size and frequency of such 337 data. 339 An In-Vehicle System (IVS) transmits an MSD (see Section 5) by 340 encoding it per Annex A of EN 15722 [msd], and including it as a MIME 341 body part within a SIP message per [RFC7852]. The body part is 342 identified by its MIME media type ('application/ 343 emergencyCallData.eCall.MSD') in the Content-Type header field of the 344 body part. The body part is assigned a unique identifier which is 345 listed in a Content-ID header field in the body part. The SIP 346 message is marked as containing the MSD by adding (or appending to) a 347 Call-Info header field at the top level of the SIP message. This 348 Call-Info header field contains a CID URL referencing the body part's 349 unique identifier, and a 'purpose' parameter identifying the data as 350 the eCall MSD per the Emergency Call Additional Data Types registry 351 entry; the 'purpose' parameter's value is 352 'emergencyCallData.eCall.MSD'. Per [RFC6086], an MSD is carried in a 353 SIP INFO request by using the INFO package defined in Section 14.9. 355 A PSAP or IVS transmits a metadata/control object (see Section 9) by 356 encoding it per the description in this document, and including it 357 within a SIP message as a MIME body part per [RFC7852]. The body 358 part is identified by its MIME media type ('application/ 359 emergencyCallData.control+xml') in the Content-Type header field of 360 the body part. The body part is assigned a unique identifier which 361 is listed in a Content-ID header field in the body part. The SIP 362 message is marked as containing the metadata/control object by adding 363 (or appending to) a Call-Info header field at the top level of the 364 SIP message. This Call-Info header field contains a CID URL 365 referencing the body part's unique identifier, and a 'purpose' 366 parameter identifying the data as an eCall metadata/control block per 367 the Emergency Call Additional Data Types registry entry; the 368 'purpose' parameter's value is 'emergencyCallData.control'. Per 369 [RFC6086], a metadata/control object is carried in a SIP INFO request 370 by using the INFO package defined in Section 14.9. 372 An MSD or a metadata/control block is always enclosed in a multipart 373 body part (even if it would otherwise be the only body part in the 374 SIP message). 376 A body part containing an MSD or metadata/control object has a 377 Content-Disposition header field value containing "By-Reference". 379 An In-Vehicle System (IVS) initiating an NG-eCall includes an MSD as 380 a body part within the initial INVITE, and optionally also includes a 381 metadata/control object informing the PSAP of its capabilities as 382 another body part. The MSD body part (and metadata/control and PIDF- 383 LO body parts if included) have a Content-Disposition header field 384 with the value "By-Reference; handling=optional". Specifying 385 "handling=optional" prevents the SIP INVITE request from being 386 rejected if it is processed by a legacy element (e.g., a gateway 387 between SIP and circuit-switched environments) that does not 388 understand the MSD (or metadata/control object or PIDF-LO). The PSAP 389 creates a metadata/control object acknowledging receipt of the MSD 390 and includes it as a body part within the SIP final response to the 391 SIP INVITE request per [RFC7852]. A metadata/control object is not 392 included in provisional (e.g., 180) responses. 394 A PSAP is able to reject a call while indicating that it is aware of 395 the situation by including a metadata/control object acknowledging 396 the MSD and containing "received=true" within a final response using 397 SIP response code 600 (Busy Everywhere), 486 (Busy Here), or 603 398 (Decline), per [RFC7852]. 400 If the IVS receives an acknowledgment for an MSD containing 401 "received=false", this indicates that the PSAP was unable to properly 402 decode or process the MSD. The IVS action is not defined (e.g., it 403 might only log an error). Since the PSAP is able to request an 404 updated MSD during the call, if an initial MSD is unsatisfactory in 405 any way, the PSAP can choose to request another one. 407 A PSAP can request that the vehicle send an updated MSD during a call 408 (e.g., upon manual request of the PSAP call taker who suspects 409 vehicle state may have changed.) To do so, the PSAP creates a 410 metadata/control object requesting an MSD and includes it within a 411 SIP INFO request sent within the dialog. The IVS then includes an 412 updated MSD within a SIP INFO request and sends it within the dialog. 413 If the IVS is unable to send an MSD, it instead sends a metadata/ 414 control object acknowledging the request with the 'success' parameter 415 set to 'false' and a 'reason' parameter (and optionally a 'details' 416 parameter) indicating why the request could not be accomplished. Per 417 [RFC6086], metadata/control objects and MSDs are sent using the INFO 418 package defined in Section 14.9. In addition, to align with how an 419 MSD or metadata/control block is transmitted in a SIP message other 420 than an INFO request, a Call-Info header field is included in the SIP 421 INFO request to reference the MSD or metadata/control block per 422 [RFC7852]. See Section 14.9 for information about the use of SIP 423 INFO requests to carry data within an eCall. 425 The IVS is not expected to send an unsolicited MSD after the initial 426 INVITE. 428 This document does not mandate support for the data blocks defined in 429 [RFC7852]. 431 7. Call Setup 433 In circuit-switched eCall, the IVS places a special form of a 112 434 emergency call which carries an eCall flag (indicating that the call 435 is an eCall and also if the call was manually or automatically 436 triggered); the mobile network operator (MNO) recognizes the eCall 437 flag and routes the call to an eCall-capable PSAP; vehicle data is 438 transmitted to the PSAP via the eCall in-band modem (in the voice 439 channel). 441 ///----\\\ 112 voice call with eCall flag +------+ 442 ||| IVS |||---------------------------------------->+ PSAP | 443 \\\----/// vehicle data via eCall in-band modem +------+ 445 Figure 1: circuit-switched eCall 447 For NG-eCall, the IVS establishes an emergency call using a Request- 448 URI indicating a manual or automatic eCall; the MNO (or ESInet) 449 recognizes the eCall URN and routes the call to an NG-eCall capable 450 PSAP; the PSAP interprets the vehicle data sent with the call and 451 makes it available to the call taker. 453 ///----\\\ IMS emergency call with eCall URN +------+ 454 IVS ----------------------------------------->+ PSAP | 455 \\\----/// vehicle data included in call setup +------+ 457 Figure 2: NG-eCall 459 See Section 6 for information on how the MSD is transported within an 460 NG-eCall. 462 This document adds new service URN children within the "sos" 463 subservice. These URNs provide the mechanism by which an eCall is 464 identified, and differentiate between manually and automatically 465 triggered eCalls (which might be subject to different treatment, 466 depending on policy). The two service URNs are: 467 urn:service:sos.ecall.automatic and urn:service:sos.ecall.manual, 468 which requests resources associated with an emergency call placed by 469 an in-vehicle system, carrying a standardized set of data related to 470 the vehicle and incident. These are registered in Section 14.2 472 Call routing is outside the scope of this document. 474 8. Test Calls 476 eCall requires the ability to place test calls (see [TS22.101] clause 477 10.7 and [EN_16062] clause 7.2.2). These are calls that are 478 recognized and treated to some extent as eCalls but are not given 479 emergency call treatment and are not handled by call takers. The 480 specific handling of test eCalls is not itself standardized; 481 typically, the test call facility allows the IVS or user to verify 482 that an eCall can be successfully established with voice 483 communication. The IVS might also be able to verify that the MSD was 484 successfully received. 486 A service URN starting with "test." indicates a test call. For 487 eCall, "urn:service:test.sos.ecall" indicates such a test feature. 488 This functionality is defined in [RFC6881]. 490 This document specifies "urn:service:test.sos.ecall" for eCall test 491 calls. This is registered in Section 14.2 493 The circuit switched eCall test call facility is a non-emergency 494 number so does not get treated as an emergency call. For NG-eCall, 495 MNOs, emergency authorities, and PSAPs can determine how to treat a 496 vehicle call requesting the "test" service URN so that the desired 497 functionality is tested, but this is outside the scope of this 498 document. 500 9. The Metadata/Control Object 502 eCall requires the ability for the PSAP to acknowledge successful 503 receipt of an MSD sent by the IVS, and for the PSAP to request that 504 the IVS send an MSD (e.g., the call taker can initiate a request for 505 a new MSD to see if there have been changes in the vehicle's state, 506 e.g., location, direction, number of fastened seatbelts). 508 This document defines a block of metadata/control data as an XML 509 structure containing elements used for eCall and other related 510 emergency call systems and extension points. (This metadata/control 511 block is in effect a high-level protocol between the PSAP and IVS.) 512 When the PSAP sends a metadata/control block in response to data sent 513 by the IVS in a SIP request other than INFO (e.g., the MSD in the 514 initial INVITE), the metadata/control block is sent in the SIP 515 response to that request (e.g., the response to the INVITE request). 516 When the PSAP sends a control block in other circumstances (e.g., 517 mid-call), the control block is transmitted from the PSAP to the IVS 518 in a SIP INFO request within the established dialog. The IVS sends 519 the requested data (the MSD) in a new SIP INFO request (per 520 [RFC6086]). This mechanism flexibly allows the PSAP to send eCall- 521 specific data to the IVS and the IVS to respond. SIP INFO requests 522 are sent using an appropriate SIP INFO Package. See Section 6 for 523 more information on sending a metadata/control block within a SIP 524 message. See Section 14.9 for information about the use of SIP INFO 525 requests to carry data within an eCall. 527 When the IVS includes an unsolicited MSD in a SIP request (e.g., the 528 initial INVITE), the PSAP sends a metadata/control block indicating 529 successful/unsuccessful receipt of the MSD in the SIP response to the 530 request. This also informs the IVS that an NG-eCall is in operation. 531 If the IVS receives a SIP final response without the metadata/control 532 block, it indicates that the SIP dialog is not an NG-eCall (e.g., 533 some part of the call is being handled as a legacy call). When the 534 IVS sends a solicited MSD (e.g., in a SIP INFO request sent following 535 receipt of a SIP INFO request containing a metadata/control block 536 requesting an MSD), the PSAP does not send a metadata/control block 537 indicating successful or unsuccessful receipt of the MSD. (Normal 538 SIP retransmission handles non-receipt of requested data; note that, 539 per [RFC6086], a 200 OK response to a SIP INFO request indicates only 540 that the receiver has successfully received and accepted the SIP INFO 541 request, it says nothing about the acceptability of the payload.) If 542 the IVS receives a request to send an MSD but it is unable to do so 543 for any reason, the IVS sends a metadata/control object acknowledging 544 the request and containing "success=false" and "reason" set to an 545 appropriate code. 547 This provides flexibility to handle various circumstances. For 548 example, if a PSAP is unable to accept an eCall (e.g., due to 549 overload or too many calls from the same location), it can reject the 550 INVITE. Since a metadata/control object is also included in the SIP 551 response that rejects the call, the IVS knows if the PSAP received 552 the MSD, and can inform the vehicle occupants that the PSAP 553 successfully received the vehicle location and information but can't 554 talk to the occupants at that time. Especially for SIP response 555 codes that indicate an inability to conduct a call (as opposed to a 556 technical inability to process the request), the IVS can also 557 determine that the call was successful on a technical level (e.g., 558 not helpful to retry as circuit-switched). (Note that there could be 559 edge cases where the PSAP response is not received by the IVS, e.g., 560 if an intermediary sends a CANCEL, and an error response is forwarded 561 towards the IVS before the error response from the PSAP is received, 562 the response will be dropped, but these are unlikely to occur here.) 564 The metadata/control block is carried in the MIME type 'application/ 565 emergencyCallData.control+xml'. 567 The metadata/control block is designed for use with pan-European 568 eCall and also eCall-like systems (i.e., in other regions), and has 569 extension points. Note that eCall-like systems might define their 570 own vehicle data blocks, and so might need to register a new INFO 571 package to accommodate the new data MIME media type and the metadata/ 572 control object. 574 9.1. The Control Block 576 The control block is an XML data structure allowing for 577 acknowledgments, requests, and capabilities information. It is 578 carried in a body part with a specific MIME media type. Three 579 elements are defined for use within a control block: 581 ack Acknowledges receipt of data or a request. 583 capabilities Used in a control block sent from the IVS to the PSAP 584 (e.g., in the initial INVITE) to inform the PSAP of the 585 vehicle capabilities. Child elements contain all 586 actions and data types supported by the vehicle. It is 587 OPTIONAL for the IVS to send this block. Omitting the 588 block indicates that the IVS supports only the 589 mandatory functionality defined in this document. 591 request Used in a control block sent by the PSAP to the IVS, to 592 request the vehicle to perform an action. 594 The element indicates the object being acknowledged and reports 595 success or failure. 597 The element contains attributes to indicate the request and 598 to supply related information. The 'action' attribute is mandatory 599 and indicates the specific action. An IANA registry is created in 600 Section 14.8.1 to contain the allowed values. 602 The element has child elements to indicate 603 the actions supported by the IVS. 605 9.1.1. The element 607 The element acknowledges receipt of an eCall data object or 608 request. An element references the Content-ID of the object 609 being acknowledged. The PSAP MUST send an element 610 acknowledging receipt of an unsolicited MSD (e.g., sent by the IVS in 611 the INVITE); this element indicates if the PSAP considers the 612 MSD successfully received or not. An element is not sent for a 613 element. 615 The element has the following attributes: 617 9.1.1.1. Attributes of the element 619 The element has the following attributes: 621 Name: ref 622 Usage: Mandatory 623 Type: anyURI 624 Direction: Sent in either direction 625 Description: References the Content-ID of the body part being 626 acknowledged. 627 Example: 629 Name: received 630 Usage: Conditional: mandatory in an element sent by a PSAP 631 Type: Boolean 632 Direction: In this document, sent from the PSAP to the IVS 633 Description: Indicates if the referenced object was considered 634 successfully received or not. 635 Example: 637 9.1.1.2. Child Element of the element 639 For extensibility, the element has the following child element: 641 Name: actionResult 642 Usage: Optional 643 Direction: Sent from the IVS to the PSAP 644 Description: An element indicates the result of an 645 action (other than a successfully executed 'send-data' action). 646 The element contains an element for each 647 element that is not a successfully executed 'send-data' 648 action. The element has the following attributes: 650 Name: action 651 Usage: Mandatory 652 Type: token 653 Description: Contains the value of the 'action' attribute of the 654 element 656 Name: success 657 Usage: Mandatory 658 Type: Boolean 659 Description: Indicates if the action was successfully 660 accomplished 662 Name: reason 663 Usage: Conditional 664 Type: token 665 Description: Used when 'success' is "false", this attribute 666 contains a reason code for a failure. A registry for reason 667 codes is defined in Section 14.8.2. The initial values are: 668 damaged (required components are damaged), data-unsupported 669 (the data item referenced in a 'send-data' request is not 670 supported), security-failure (the authenticity of the request 671 or the authority of the requestor could not be verified), 672 unable (a generic error for use when no other code is 673 appropriate), and unsupported (the 'action' value is not 674 supported). 676 Name: details 677 Usage: optional 678 Type: string 679 Description: Contains further explanation of the circumstances of 680 a success or failure. The contents are implementation-specific 681 and human-readable. This is intended for internal use and 682 troubleshooting, not for display to vehicle occupants. 684 9.1.1.3. Ack Examples 686 687 691 693 695 Figure 3: Ack Example from PSAP to IVS 697 9.1.2. The element 699 The element is transmitted by the IVS to indicate to 700 the PSAP its capabilities. No attributes for this element are 701 currently defined. The following child elements are defined: 703 9.1.2.1. Child Element of the element 705 The element has the following child element: 707 Name: request 708 Usage: Mandatory 709 Description: The element contains a child 710 element per action supported by the vehicle. 712 Example: 714 716 718 720 It is OPTIONAL for the IVS to support the element. If 721 the IVS does not send a element, this indicates that 722 the only action supported by the IVS is 'send-data' with 723 'datatype' set to 'eCall.MSD'. 725 9.1.2.2. Capabilities Example 727 728 731 732 733 735 737 Figure 4: Capabilities Example 739 9.1.3. The element 741 A element appears one or more times on its own or as a 742 child of a element. It allows the PSAP to request 743 that the IVS perform an action. The only action that MUST be 744 supported is to send an MSD. The following attributes and child 745 elements are defined: 747 9.1.3.1. Attributes of the element 749 The element has the following attributes: 751 Name: action 752 Usage: Mandatory 753 Type: token 754 Direction: Sent in either direction 755 Description: Identifies the action that the vehicle is requested to 756 perform (in a element within a element, 757 indicates an action that the vehicle is capable of performing). 758 An IANA registry is established in Section 14.8.1 to contain the 759 allowed values. 760 Example: action="send-data" 762 Name: int-id 763 Usage: Conditional 764 Type: int 765 Direction: Sent in either direction 766 Description: Defined for extensibility. Documents that make use of 767 it are expected to explain when it is required and how it is used. 768 Example: int-id="3" 770 Name: persistence 771 Usage: Optional 772 Type: xs:duration 773 Direction: Sent in either direction 774 Description: Defined for extensibility. Specifies how long to carry 775 on the specified action. If absent, the default is for the 776 duration of the call. 777 Example: persistence="PT1H" 779 Name: datatype 780 Usage: Conditional 781 Type: token 782 Direction: Sent in either direction 783 Description: Mandatory with a "send-data" action within a 784 element that is not within a element. Specifies 785 the data block that the IVS is requested to transmit, using the 786 same identifier as in the 'purpose' attribute set in a Call-Info 787 header field to point to the data block. Permitted values are 788 contained in the 'Emergency Call Data Types' IANA registry 789 established in [RFC7852]. Only the "eCall.MSD" value is mandatory 790 to support. 791 Example: datatype="eCall.MSD" 793 Name: supported-values 794 Usage: Conditional 795 Type: string 796 Direction: Sent from the IVS to the PSAP 797 Description: Defined for extensibility. Used in a element 798 that is a child of a element, this attribute lists 799 all supported values of the action type. Permitted values depend 800 on the action value. Multiple values are separated with a 801 semicolon. White space is ignored. Documents that make use of it 802 are expected to explain when it is required, the permitted values, 803 and how it is used. 805 Name: requested-state 806 Usage: Conditional 807 Type: token 808 Direction: Sent from the PSAP to the IVS 809 Description: Defined for extension. Indicates the requested state 810 of an element associated with the request type. Permitted values 811 depend on the request type. Documents that make use of it are 812 expected to explain when it is required, the permitted values, and 813 how it is used. 815 Name: element-id 816 Usage: Conditional 817 Type: token 818 Direction: Sent from the PSAP to the IVS 819 Description: Defined for extension. Identifies the element to be 820 acted on. Permitted values depend on the request type. Documents 821 that make use of it are expected to explain when it is required, 822 the permitted values, and how it is used. 824 9.1.3.2. Request Example 826 827 830 832 834 Figure 5: Request Example 836 10. Examples 838 Figure 6 illustrates an eCall. The call uses the request URI 839 'urn:service:sos.ecall.automatic' service URN and is recognized as an 840 eCall, and further as one that was invoked automatically by the IVS 841 due to a crash or other serious incident. In this example, the 842 originating network routes the call to an ESInet which routes the 843 call to the appropriate NG-eCall capable PSAP. The emergency call is 844 received by the ESInet's Emergency Services Routing Proxy (ESRP), as 845 the entry point into the ESInet. The ESRP routes the call to a PSAP, 846 where it is received by a call taker. In deployments where there is 847 no ESInet, the originating network routes the call directly to the 848 appropriate NG-eCall capable PSAP, an illustration of which would be 849 identical to the one below except without an ESInet or ESRP. 851 +------------+ +---------------------------------------+ 852 | | | +-------+ | 853 | | | | PSAP2 | | 854 | | | +-------+ | 855 | | | | 856 | | | +------+ +-------+ | 857 Vehicle-->| |--+->| ESRP |---->| PSAP1 |--> Call-Taker | 858 | | | +------+ +-------+ | 859 | | | | 860 | | | +-------+ | 861 | | | | PSAP3 | | 862 | Originating| | +-------+ | 863 | Mobile | | | 864 | Network | | ESInet | 865 +------------+ +---------------------------------------+ 867 Figure 6: Example of NG-eCall Message Flow 869 Figure 7 illustrates an eCall call flow with a mid-call PSAP request 870 for an updated MSD. The call flow shows the IVS initiating an 871 emergency call, including the MSD in the INVITE. The PSAP includes 872 in the 200 OK response a metadata/control object acknowledging 873 receipt of the MSD. During the call, the PSAP sends a request for an 874 MSD in an INFO request. The IVS sends the requested MSD in a new 875 INFO request. 877 IVS PSAP 878 |(1) INVITE (eCall MSD) | 879 |------------------------------------------->| 880 | | 881 |(2) 200 OK (eCall metadata [ack MSD]) | 882 |<-------------------------------------------| 883 | | 884 |(3) start media stream(s) | 885 |............................................| 886 | | 887 |(4) INFO (eCall metadata [request MSD]) | 888 |<-------------------------------------------| 889 | | 890 |(5) 200 OK | 891 |------------------------------------------->| 892 | | 893 |(6) INFO (eCall MSD) | 894 |------------------------------------------->| 895 | | 896 |(7) 200 OK | 897 |<-------------------------------------------| 898 | | 899 |(8) BYE | 900 |<-------------------------------------------| 901 | | 902 |(9) end media streams | 903 |............................................| 904 | | 905 |(10) 200 OK | 906 |------------------------------------------->| 908 Figure 7: NG-eCall Call Flow Illustration 910 The example, shown in Figure 8, illustrates a SIP eCall INVITE 911 request containing an MSD. For simplicity, the example does not show 912 all SIP headers, nor the SDP contents, nor does it show any 913 additional data blocks added by the IVS or the originating mobile 914 network. Because the MSD is encoded in ASN.1 PER, which is a binary 915 encoding, its contents cannot be included in a text document. 917 INVITE urn:service:sos.ecall.automatic SIP/2.0 918 To: urn:service:sos.ecall.automatic 919 From: ;tag=9fxced76sl 920 Call-ID: 3848276298220188511@atlanta.example.com 921 Geolocation: 922 Geolocation-Routing: no 923 Call-Info: ; 924 purpose=emergencyCallData.eCall.MSD 925 Accept: application/sdp, application/pidf+xml, 926 application/emergencyCallData.control+xml 927 CSeq: 31862 INVITE 928 Recv-Info: emergencyCallData.eCall.MSD 929 Allow: INVITE, ACK, PRACK, INFO, OPTIONS, CANCEL, REFER, BYE, 930 SUBSCRIBE, NOTIFY, UPDATE 931 Content-Type: multipart/mixed; boundary=boundary1 932 Content-Length: ... 934 --boundary1 935 Content-Type: application/sdp 937 ...Session Description Protocol (SDP) goes here... 939 --boundary1 940 Content-Type: application/pidf+xml 941 Content-ID: 942 Content-Disposition: by-reference;handling=optional 944 ...PIDF-LO goes in here 946 --boundary1 947 Content-Type: application/emergencyCallData.eCall.MSD 948 Content-ID: <1234567890@atlanta.example.com> 949 Content-Disposition: by-reference;handling=optional 951 ...MSD in ASN.1 PER encoding goes here... 953 --boundary1-- 955 Figure 8: SIP NG-eCall INVITE 957 Continuing the example, Figure 9 illustrates a SIP 200 OK response to 958 the INVITE request of Figure 8, containing a control block 959 acknowledging successful receipt of the eCall MSD. (For simplicity, 960 the example does not show all SIP headers.) 961 SIP/2.0 200 OK 962 To: urn:service:sos.ecall.automatic;tag=8gydfe65t0 963 From: ;tag=9fxced76sl 964 Call-ID: 3848276298220188511@atlanta.example.com 965 Call-Info: ; 966 purpose=emergencyCallData.control 967 Accept: application/sdp, application/pidf+xml, 968 application/emergencyCallData.control+xml, 969 application/emergencyCallData.eCall.MSD 970 CSeq: 31862 INVITE 971 Recv-Info: emergencyCallData.eCall.MSD 972 Allow: INVITE, ACK, PRACK, INFO, OPTIONS, CANCEL, REFER, BYE, 973 SUBSCRIBE, NOTIFY, UPDATE 974 Content-Type: multipart/mixed; boundary=boundaryX 975 Content-Length: ... 977 --boundaryX 978 Content-Type: application/sdp 980 ...Session Description Protocol (SDP) goes here... 982 --boundaryX 983 Content-Type: application/emergencyCallData.control+xml 984 Content-ID: <2345678901@atlanta.example.com> 985 Content-Disposition: by-reference 987 988 991 992 994 --boundaryX-- 996 Figure 9: 200 OK response to INVITE 998 Figure 10 illustrates a SIP INFO request containing a metadata/ 999 control block requesting an eCall MSD. (For simplicity, the example 1000 does not show all SIP headers.) 1001 INFO sip:+13145551111@example.com SIP/2.0 1002 To: ;tag=9fxced76sl 1003 From: Exemplar PSAP ;tag=8gydfe65t0 1004 Call-ID: 3848276298220188511@atlanta.example.com 1005 Call-Info: ; 1006 purpose=emergencyCallData.control 1007 CSeq: 41862 INFO 1008 Info-Package: emergencyCallData.eCall.MSD 1009 Allow: INVITE, ACK, PRACK, INFO, OPTIONS, CANCEL, REFER, BYE, 1010 SUBSCRIBE, NOTIFY, UPDATE 1011 Content-Type: multipart/mixed; boundary=boundaryZZZ 1012 Content-Disposition: Info-Package 1013 Content-Length: ... 1015 --boundaryZZZ 1016 Content-Disposition: by-reference 1017 Content-Type: application/emergencyCallData.control+xml 1018 Content-ID: <3456789012@atlanta.example.com> 1020 1021 1024 1026 1027 --boundaryZZZ-- 1029 Figure 10: INFO requesting MSD 1031 Figure 11 illustrates a SIP INFO request containing an MSD. For 1032 simplicity, the example does not show all SIP headers. Because the 1033 MSD is encoded in ASN.1 PER, which is a binary encoding, its contents 1034 cannot be included in a text document. 1036 INFO urn:service:sos.ecall.automatic SIP/2.0 1037 To: urn:service:sos.ecall.automatic;tag=8gydfe65t0 1038 From: ;tag=9fxced76sl 1039 Call-ID: 3848276298220188511@atlanta.example.com 1040 Call-Info: ; 1041 purpose=emergencyCallData.eCall.MSD 1042 CSeq: 51862 INFO 1043 Info-Package: emergencyCallData.eCall.MSD 1044 Allow: INVITE, ACK, PRACK, INFO, OPTIONS, CANCEL, REFER, BYE, 1045 SUBSCRIBE, NOTIFY, UPDATE 1046 Content-Type: multipart/mixed; boundary=boundaryLine 1047 Content-Disposition: Info-Package 1048 Content-Length: ... 1050 --boundaryLine 1051 Content-Type: application/emergencyCallData.eCall.MSD 1052 Content-ID: <4567890123@atlanta.example.com> 1053 Content-Disposition: by-reference 1055 ...MSD in ASN.1 PER encoding goes here... 1057 --boundaryLine-- 1059 Figure 11: INFO containing MSD 1061 11. Security Considerations 1063 The security considerations described in [RFC5069] (on marking and 1064 routing emergency calls) apply here. 1066 In addition to any network-provided location (which might be 1067 determined solely by the network, or in cooperation with or possibly 1068 entirely by the originating device), an eCall carries an IVS-supplied 1069 location within the MSD. This is likely to be useful to the PSAP, 1070 especially when no network-provided location is included, or when the 1071 two locations are independently determined. Even in situations where 1072 the network-supplied location is limited to the cell site, this can 1073 be useful as a sanity check on the device-supplied location contained 1074 in the MSD. 1076 The document [RFC7378] discusses trust issues regarding location 1077 provided by or determined in cooperation with end devices. 1079 Security considerations specific to the mechanism by which the PSAP 1080 sends acknowledgments and requests to the vehicle are discussed in 1081 the "Security Considerations" block of Section 14.4. Note that an 1082 attacker that has access to and is capable of generating a response 1083 to the initial INVITE request could generate a 600 (Busy Everywhere), 1084 486 (Busy Here), or 603 (Decline) response that includes a metadata/ 1085 control object containing a reference to the MSD in the initial 1086 INVITE and a "received=true" field, which could result in the IVS 1087 perceiving the PSAP to be overloaded and hence not attempting to 1088 reinitiate the call. The risk can be mitigated as discussed in the 1089 "Security Considerations" block of Section 14.4. 1091 Data received from external sources inherently carries implementation 1092 risks. For example, depending on the platform, buffer overflows can 1093 introduce remote code execution vulnerabilities, null characters can 1094 corrupt strings, numeric values used for internal calculations can 1095 result in underflow/overflow errors, malformed XML objects can expose 1096 parsing bugs, etc. Implementations need to be cognizant of the 1097 potential risks, observe best practices (which might include 1098 sufficiently capable static code analysis, fuzz testing, component 1099 isolation, avoiding use of unsafe coding techniques, third-party 1100 attack tests, signed software, over-the-air updates, etc.), and have 1101 multiple levels of protection. Implementors need to be aware that, 1102 potentially, the data objects described here and elsewhere (including 1103 the MSD and metadata/control objects) might be malformed, might 1104 contain unexpected characters, excessively long attribute values, 1105 elements, etc. 1107 The security considerations discussed in [RFC7852] apply here (see 1108 especially the discussion of TLS, TLS versions, cipher suites, and 1109 PKI). 1111 When vehicle data or control/metadata is contained in a signed or 1112 encrypted body part, the enclosing multipart (e.g., multipart/signed 1113 or multipart/encrypted) has the same Content-ID as the enclosed data 1114 part. This allows an entity to identify and access the data blocks 1115 it is interested in without having to dive deeply into the message 1116 structure or decrypt parts it is not interested in. (The 'purpose' 1117 parameter in a Call-Info header field identifies the data and 1118 contains a CID URL pointing to the data block in the body, which has 1119 a matching Content-ID body part header field). 1121 12. Privacy Considerations 1123 The privacy considerations discussed in [RFC7852] apply here. The 1124 MSD carries some identifying and personal information (mostly about 1125 the vehicle and less about the owner), as well as location 1126 information, and so needs to be protected against unauthorized 1127 disclosure. Local regulations may impose additional privacy 1128 protection requirements. 1130 Privacy considerations specific to the data structure containing 1131 vehicle information are discussed in the "Security Considerations" 1132 block of Section 14.3. 1134 Privacy considerations specific to the mechanism by which the PSAP 1135 sends acknowledgments and requests to the vehicle are discussed in 1136 the "Security Considerations" block of Section 14.4. 1138 13. XML Schema 1140 This section defines an XML schema for the control block. The text 1141 description of the control block in Section 9.1 is normative and 1142 supersedes any conflicting aspect of this schema. 1144 1145 1153 1155 1158 1159 1160 1161 1162 1164 1165 1166 1169 1170 1171 1172 1173 1175 1176 1177 1178 1179 1181 1182 1185 1188 1190 1191 1192 conditionally mandatory 1193 when @success="false" 1194 to indicate reason code 1195 for a failure 1196 1197 1198 1199 1201 1203 1204 1205 1208 1209 1212 1214 1215 1216 1217 1219 1220 1221 1222 1223 1227 1230 1231 1232 1233 1234 1236 1237 1238 1239 1240 1243 1244 1246 1247 1249 1250 1252 1253 1255 1256 1257 1258 1260 1262 Figure 12: Control Block Schema 1264 14. IANA Considerations 1266 14.1. The EmergencyCallData Media Subtree 1268 This document establishes the "EmergencyCallData" media (MIME) 1269 subtype tree, a new media subtree rooted at "application/ 1270 EmergencyCallData". This subtree is used only for content associated 1271 with emergency communications. New subtypes in this subtree follow 1272 the rules specified in Section 3.1 of [RFC6838], with the additional 1273 restriction that the standards-related organization MUST be 1274 responsible for some aspect of emergency communications. 1276 This subtree initially contains the following subtypes (defined here 1277 or in [RFC7852]): 1279 emergencyCallData.control+xml 1280 EmergencyCallData.Comment+xml 1281 EmergencyCallData.DeviceInfo+xml 1282 EmergencyCallData.MSD 1283 EmergencyCallData.ProviderInfo+xml 1284 EmergencyCallData.ServiceInfo+xml 1285 EmergencyCallData.SubscriberInfo+xml 1287 14.2. Service URN Registrations 1289 IANA is requested to register the URN 'urn:service:sos.ecall' under 1290 the sub-services 'sos' registry defined in Section 4.2 of [RFC5031]. 1292 This service requests resources associated with an emergency call 1293 placed by an in-vehicle system, carrying a standardized set of data 1294 related to the vehicle and incident. Two sub-services are registered 1295 as well: 1297 urn:service:sos.ecall.manual 1299 Used with an eCall invoked due to manual interaction by a vehicle 1300 occupant. 1302 urn:service:sos.ecall.automatic 1304 Used with an eCall invoked automatically, for example, due to a 1305 crash or other serious incident. 1307 IANA is also requested to register the URN 1308 'urn:service:test.sos.ecall' under the sub-service 'test' registry 1309 defined in Setcion 17.2 of [RFC6881]. This service requests 1310 resources associated with a test (non-emergency) call placed by an 1311 in-vehicle system. See Section 8 for more information on the test 1312 eCall request URN. 1314 14.3. MIME Media Type Registration for 'application/ 1315 emergencyCallData.eCall.MSD' 1317 IANA is requested to add application/emergencyCallData.eCall.MSD as a 1318 MIME media type, with a reference to this document, in accordance to 1319 the procedures of RFC 6838 [RFC6838] and guidelines in RFC 7303 1320 [RFC7303]. 1322 MIME media type name: application 1324 MIME subtype name: emergencyCallData.eCall.MSD 1326 Mandatory parameters: none 1328 Optional parameters: none 1330 Encoding scheme: binary 1332 Encoding considerations: Uses ASN.1 PER, which is a binary 1333 encoding; when transported in SIP, binary content transfer 1334 encoding is used. 1336 Security considerations: This media type is designed to carry 1337 vehicle and incident-related data during an emergency call. This 1338 data contains personal information including vehicle VIN, 1339 location, direction, etc. Appropriate precautions need to be 1340 taken to limit unauthorized access, inappropriate disclosure to 1341 third parties, and eavesdropping of this information. Sections 9 1342 and Section 10 of [RFC7852] contain more discussion. 1344 Interoperability considerations: None 1346 Published specification: Annex A of EN 15722 [msd] 1348 Applications which use this media type: Pan-European eCall 1349 compliant systems 1351 Additional information: None 1353 Magic Number: None 1355 File Extension: None 1357 Macintosh file type code: 'BINA' 1359 Person and email address for further information: Randall Gellens, 1360 rg+ietf@randy.pensive.org 1362 Intended usage: LIMITED USE 1364 Author: The MSD specification was produced by the European 1365 Committee For Standardization (CEN). For contact information, 1366 please see . 1368 Change controller: The European Committee For Standardization 1369 (CEN) 1371 14.4. MIME Media Type Registration for 'application/ 1372 emergencyCallData.control+xml' 1374 IANA is requested to add application/emergencyCallData.control+xml as 1375 a MIME media type, with a reference to this document, in accordance 1376 to the procedures of RFC 6838 [RFC6838] and guidelines in RFC 7303 1377 [RFC7303]. 1379 MIME media type name: application 1381 MIME subtype name: emergencyCallData.control+xml 1383 Mandatory parameters: none 1385 Optional parameters: charset 1387 Indicates the character encoding of the XML content. 1389 Encoding considerations: Uses XML, which can employ 8-bit 1390 characters, depending on the character encoding used. See 1391 Section 3.2 of RFC 7303 [RFC7303]. 1393 Security considerations: 1395 This media type carries metadata and control information and 1396 requests, such as from a Public Safety Answering Point (PSAP) 1397 to an In-Vehicle System (IVS) during an emergency call. 1399 Metadata (such as an acknowledgment that data sent by the IVS 1400 to the PSAP was successfully received) has limited privacy and 1401 security implications. Control information (such as requests 1402 from the PSAP that the vehicle perform an action) has some 1403 privacy and security implications. The privacy concern arises 1404 from the ability to request the vehicle to transmit a data set, 1405 which as described in Section 14.3, can contain personal 1406 information. The security concern is the ability to request 1407 the vehicle to perform an action. Control information needs to 1408 originate only from a PSAP or other emergency services 1409 provider, and not be modified en-route. The level of integrity 1410 of the cellular network over which the emergency call is placed 1411 is a consideration: when the IVS initiates an eCall over a 1412 cellular network, in most cases it relies on the MNO to route 1413 the call to a PSAP. (Calls placed using other means, such as 1414 Wi-Fi or over-the-top services, generally incur somewhat higher 1415 levels of risk than calls placed "natively" using cellular 1416 networks.) A call-back from a PSAP merits additional 1417 consideration, since current mechanisms are not ideal for 1418 verifying that such a call is indeed a call-back from a PSAP in 1419 response to an emergency call placed by the IVS. See the 1420 discussion in Section 11 and the PSAP Callback document 1421 [RFC7090]. 1423 Sections 7 and Section 8 of [RFC7852] contain more discussion. 1425 Interoperability considerations: None 1427 Published specification: This document 1429 Applications which use this media type: Pan-European eCall 1430 compliant systems 1432 Additional information: None 1434 Magic Number: None 1436 File Extension: .xml 1438 Macintosh file type code: 'TEXT' 1440 Person and email address for further information: Randall Gellens, 1441 rg+ietf@randy.pensive.org 1443 Intended usage: LIMITED USE 1445 Author: The IETF ECRIT WG. 1447 Change controller: The IETF ECRIT WG. 1449 14.5. Registration of the 'eCall.MSD' entry in the Emergency Call 1450 Additional Data Types registry 1452 This specification requests IANA to add the 'eCall.MSD' entry to the 1453 Emergency Call Additional Data Types registry, with a reference to 1454 this document; the 'Data About' value is 'The Call'. 1456 14.6. Registration of the 'control' entry in the Emergency Call 1457 Additional Data Types registry 1459 This specification requests IANA to add the 'control' entry to the 1460 Emergency Call Additional Data Types registry, with a reference to 1461 this document; the 'Data About' value is 'The Call'. 1463 14.7. Registration for urn:ietf:params:xml:ns:EmergencyCallData:control 1465 This section registers a new XML namespace, as per the guidelines in 1466 RFC 3688 [RFC3688]. 1468 URI: urn:ietf:params:xml:ns:EmergencyCallData:control 1470 Registrant Contact: IETF, ECRIT working group, , as 1471 delegated by the IESG . 1473 XML: 1475 BEGIN 1476 1477 1479 1480 1481 1483 Namespace for Emergency Call Data Control Block 1484 1485 1486

Namespace for Emergency Call Data Control Block

1487

See [TBD: This document].

1488 1489 1490 END 1492 14.8. Registry Creation 1494 This document creates a new registry called "Emergency Call Metadata/ 1495 Control Data". The following sub-registries are created for this 1496 registry. 1498 14.8.1. Emergency Call Action Registry 1500 This document creates a new sub-registry called "Emergency Call 1501 Action". As defined in [RFC5226], this registry operates under 1502 "Expert Review" rules. The expert should determine that the proposed 1503 action is within the purview of a vehicle, is sufficiently 1504 distinguishable from other actions, and the action is clearly and 1505 fully described. In most cases, a published and stable document is 1506 referenced for the description of the action. 1508 The content of this registry includes: 1510 Name: The identifier to be used in the 'action' attribute of a 1511 control element. 1513 Description: A description of the action. In most cases this will 1514 be a reference to a published and stable document. The 1515 description MUST specify if any attributes or child elements are 1516 optional or mandatory, and describe the action to be taken by the 1517 vehicle. 1519 The initial set of values is listed in Table 2. 1521 +-----------+--------------------------------------+ 1522 | Name | Description | 1523 +-----------+--------------------------------------+ 1524 | send-data | See Section 9.1.3.1 of this document | 1525 +-----------+--------------------------------------+ 1527 Table 2: Emergency Call Action Registry Initial Values 1529 14.8.2. Emergency Call Action Failure Reason Registry 1531 This document creates a new sub-registry called "Emergency Call 1532 Action Failure Reason" which contains values for the 'reason' 1533 attribute of the element. As defined in [RFC5226], 1534 this registry operates under "Expert Review" rules. The expert 1535 should determine that the proposed reason is sufficiently 1536 distinguishable from other reasons and that the proposed description 1537 is understandable and correctly worded. 1539 The content of this registry includes: 1541 ID: A short string identifying the reason, for use in the 'reason' 1542 attribute of an element. 1544 Description: A description of the reason. 1546 The initial set of values is listed in Table 3. 1548 +------------------+------------------------------------------------+ 1549 | ID | Description | 1550 +------------------+------------------------------------------------+ 1551 | damaged | Required components are damaged. | 1552 | | | 1553 | data-unsupported | The data item referenced in a 'send-data' | 1554 | | request is not supported. | 1555 | | | 1556 | security-failure | The authenticity of the request or the | 1557 | | authority of the requestor could not be | 1558 | | verified. | 1559 | | | 1560 | unable | The action could not be accomplished (a | 1561 | | generic error for use when no other code is | 1562 | | appropriate). | 1563 | | | 1564 | unsupported | The 'action' value is not supported. | 1565 +------------------+------------------------------------------------+ 1567 Table 3: Emergency Call Action Failure Reason Registry Initial Values 1569 14.9. The emergencyCallData.eCall.MSD INFO package 1571 This document registers the 'emergencyCallData.eCall.MSD' INFO 1572 package. 1574 Both endpoints (the IVS and the PSAP equipment) include 1575 'emergencyCallData.eCall.MSD' in a Recv-Info header field per 1576 [RFC6086] to indicate ability to receive INFO requests carrying data 1577 as described here. 1579 Support for the 'emergencyCallData.eCall.MSD' INFO package indicates 1580 the ability to receive eCall related body parts as specified in [TBD: 1581 THIS DOCUMENT]. 1583 An INFO request message carrying body parts related to an emergency 1584 call as described in [TBD: THIS DOCUMENT] has an Info-Package header 1585 field set to 'emergencyCallData.eCall.MSD' per [RFC6086]. 1587 The requirements of Section 10 of [RFC6086] are addressed in the 1588 following sections. 1590 14.9.1. Overall Description 1592 This section describes "what type of information is carried in INFO 1593 requests associated with the Info Package, and for what types of 1594 applications and functionalities UAs can use the Info Package." 1595 INFO requests associated with the emergencyCallData.eCall.MSD INFO 1596 package carry data associated with emergency calls as defined in 1597 [TBD: THIS DOCUMENT]. The application is vehicle-initiated emergency 1598 calls established using SIP. The functionality is to carry vehicle 1599 data and metadata/control information between vehicles and PSAPs. 1600 Refer to [TBD: THIS DOCUMENT] for more information. 1602 14.9.2. Applicability 1604 This section describes "why the Info Package mechanism, rather than 1605 some other mechanism, has been chosen for the specific use-case...." 1607 The use of the SIP INFO method is based on an analysis of the 1608 requirements against the intent and effects of the INFO method versus 1609 other approaches (which included the SIP MESSAGE method, the SIP 1610 OPTIONS method, the SIP re-INVITE method, media plane transport, and 1611 non-SIP protocols). In particular, the transport of emergency call 1612 data blocks occurs within a SIP emergency dialog, per Section 6, and 1613 is normally carried in the initial INVITE request and response; the 1614 use of the SIP INFO method only occurs when emergency-call-related 1615 data needs to be sent mid-call. While the SIP MESSAGE method could 1616 be used, it is not tied to a SIP dialog as is the SIP INFO method and 1617 thus might not be associated with the dialog. Either the SIP OPTIONS 1618 or re-INVITE methods could also be used, but is seen as less clean 1619 than the SIP INFO method. The SIP SUBSCRIBE/NOTIFY method could be 1620 coerced into service, but the semantics are not a good fit, e.g., the 1621 subscribe/notify mechanism provides one-way communication consisting 1622 of (often multiple) notifications from notifier to subscriber 1623 indicating that certain events in notifier have occurred, whereas 1624 what's needed here is two-way communication of data related to the 1625 emergency dialog. Use of the media plane mechanisms was discounted 1626 because the number of messages needing to be exchanged in a dialog is 1627 normally zero or very few, and the size of the data is likewise very 1628 small. The overhead caused by user plane setup (e.g., to use MSRP as 1629 transport) would be disproportionately large. 1631 Based on the analyses, the SIP INFO method was chosen to provide for 1632 mid-call data transport. 1634 14.9.3. Info Package Name 1636 The info package name is emergencyCallData.eCall.MSD 1638 14.9.4. Info Package Parameters 1640 None 1642 14.9.5. SIP Option-Tags 1644 None 1646 14.9.6. INFO Request Body Parts 1648 The body for an emergencyCallData.eCall.MSD info package is a 1649 multipart (normally multipart/mixed) body containing zero or one 1650 application/emergencyCallData.eCall.MSD part (containing an MSD) and 1651 zero or more application/emergencyCallData.control+xml (containing a 1652 metadata/control object) parts. At least one MSD or metadata/control 1653 body part is expected; the behavior upon receiving an INFO request 1654 with neither is undefined. 1656 The body parts are sent per [RFC6086], and in addition, to align with 1657 with how these body parts are sent in SIP messages other than INFO 1658 requests, each associated body part is referenced by a Call-Info 1659 header field at the top level of the SIP message. The body part has 1660 a Content-Disposition header field set to "By-Reference". 1662 An MSD or metadata/control block is always enclosed in a multipart 1663 body part (even if it would otherwise be the only body part in the 1664 SIP message). The innermost multipart that contains only body parts 1665 associated with the INFO package has a Content-Disposition value of 1666 Info-Package. 1668 See [TBD: THIS DOCUMENT] for more information. 1670 14.9.7. Info Package Usage Restrictions 1672 Usage is limited to vehicle-initiated emergency calls as defined in 1673 [TBD: THIS DOCUMENT]. 1675 14.9.8. Rate of INFO Requests 1677 The SIP INFO request is used within an established emergency call 1678 dialog for the PSAP to request the IVS to send an updated MSD, and 1679 for the IVS to send a requested MSD. Because this is normally done 1680 only on manual request of the PSAP call taker (who suspects some 1681 aspect of the vehicle state has changed), the rate of SIP INFO 1682 requests associated with the emergencyCallData.eCall.MSD info package 1683 is normally quite low (most dialogs are likely to contain zero INFO 1684 requests, while others might carry an occasional request). 1686 14.9.9. Info Package Security Considerations 1688 The MIME media type registrations specified for use with this INFO 1689 package (Section 14.3 and Section 14.4) contain a discussion of the 1690 security and/or privacy considerations specific to that data block. 1691 The "Security Considerations" and "Privacy Considerations" sections 1692 of [TBD: THIS DOCUMENT] discuss security and privacy considerations 1693 of the data carried in eCalls. 1695 14.9.10. Implementation Details 1697 See [TBD: THIS DOCUMENT] for protocol details. 1699 14.9.11. Examples 1701 See [TBD: THIS DOCUMENT] for protocol examples. 1703 15. Contributors 1705 Brian Rosen was a co-author of the original document upon which this 1706 document is based. 1708 16. Acknowledgements 1710 We would like to thank Bob Williams and Ban Al-Bakri for their 1711 feedback and suggestion; Rex Buddenberg, Lena Chaponniere, Alissa 1712 Cooper, Keith Drage, Stephen Edge, Wes George, Mirja Kuehlewind, 1713 Allison Mankin, Alexey Melnikov, Ivo Sedlacek, and James Winterbottom 1714 for their review and comments; Robert Sparks and Paul Kyzivat for 1715 their help with the SIP mechanisms; Mark Baker and Ned Freed for 1716 their help with the media subtype registration issue. We would like 1717 to thank Michael Montag, Arnoud van Wijk, Gunnar Hellstrom, and 1718 Ulrich Dietz for their help with the original document upon which 1719 this document is based. Christer Holmberg deserves special mention 1720 for his many detailed reviews. 1722 17. Changes from Previous Versions 1724 RFC Editor: Please remove this section prior to publication. 1726 17.1. Changes from draft-ietf-19 to draft-ietf-20 1728 o Fixed various nits 1730 17.2. Changes from draft-ietf-18 to draft-ietf-19 1732 o Added additional text to "Rate of Info Requests" 1733 o Added additional text to "Security Considerations" 1734 o Further corrected "content type" to "media type" 1736 17.3. Changes from draft-ietf-17 to draft-ietf-18 1738 o Added reference to 3GPP TS24.229 1739 o Clarified that an INFO request is expected to have at least one 1740 MSD or metadata/control body part 1741 o Fixed minor errors in examples 1742 o Corrected "content type" to "media type" 1743 o Deleted "xsi:schemaLocation" from examples 1745 17.4. Changes from draft-ietf-16 to draft-ietf-17 1747 o Clarify Content-Disposition value in INFO requests 1749 17.5. Changes from draft-ietf-15 to draft-ietf-16 1751 o Various clarifications and simplifications 1752 o Added reference to 3GPP 23.167 1754 17.6. Changes from draft-ietf-14 to draft-ietf-15 1756 o eCall body parts now always sent enclosed in multipart (even if 1757 only body part in SIP message) and hence always have a Content- 1758 Disposition of By-Reference 1759 o Fixed errors in attribute directionality text 1760 o Fixed typos. 1762 17.7. Changes from draft-ietf-13 to draft-ietf-14 1764 o Added text to the IANA Considerations to formalize the 1765 EmergencyCallData media subtree 1766 o Fixed some typos 1768 17.8. Changes from draft-ietf-12 to draft-ietf-13 1770 o Clarifications suggested by Christer 1771 o Corrections to Content-Disposition text and examples as suggested 1772 by Paul Kyzivat 1773 o Clarifications to Content-Disposition text and examples to clarify 1774 that handling=optional is only used in the initial INVITE 1776 17.9. Changes from draft-ietf-11 to draft-ietf-12 1778 o Fixed errors in examples found by Dale 1779 o Removed enclosing sub-section of INFO package registration section 1780 o Added text per Christer and Dale's suggestions that the MSD and 1781 metadata/control blocks are sent in INFO with a Call-Info header 1782 field referencing them 1783 o Deleted Call Routing section (7.1) in favor of a statement that 1784 call routing is outside the scope of the document 1785 o Other text changes per comments received from Christer and Ivo. 1787 17.10. Changes from draft-ietf-09 to draft-ietf-11 1789 o Renamed INFO package to emergencyCallData.eCall.MSD 1790 o Changed INFO package to only permit MSD and metadata/control MIME 1791 types 1792 o Moved element back from car-crash but made it 1793 OPTIONAL 1794 o Moved other extension points back from car-crash so that extension 1795 points are in base spec (and also to get XML schema to compile) 1796 o Text changes for clarification. 1798 17.11. Changes from draft-ietf-08 to draft-ietf-09 1800 o Created a new "Data Transport" section that describes how the MSD 1801 and metadata/control blocks are attached, and then referred to 1802 that section rather than repeat the information about the CID and 1803 Call-Info and so forth, which means most references to the 1804 additional-data draft have now been deleted 1805 o Mentioned edge cases where a PSAP response to INVITE isn't 1806 received by the IVS 1807 o Reworded description of which status codes are used when a PSAP 1808 wishes to reject a call but inform the vehicle occupants that it 1809 is aware of the situation to be more definite 1810 o Added examples showing INFO 1811 o Added references for eCall test call requirement 1812 o Described meaning of eCall URNs in Section 8 as well as in IANA 1813 registration 1815 17.12. Changes from draft-ietf-07 to draft-ietf-08 1817 o eCall MSD now encoded as ASN.1 PER, using binary content transfer 1818 encoding 1819 o Added text to point out aspects of call handling and metadata/ 1820 control usage, such as use in rejected calls, and solicited MSDs 1821 o Revised use of INFO to require that when a request for an MSD is 1822 sent in INFO, the MSD sent in response is in its own INFO, not the 1823 response to the requesting INFO 1825 o Added material to INFO package registation to comply with 1826 Section 10 of [RFC6086] 1827 o Moved material not required by 3GPP into 1828 [I-D.ietf-ecrit-car-crash], e.g., some of the eCall metadata/ 1829 control elements, attributes, and values 1830 o Revised test call wording to clarify that specific handling is out 1831 of scope 1832 o Revised wording throughout the document to simplify 1833 o Moved new Section 7.1 to be a subsection of 7 1834 o Moved new Section Section 14.9 to be a main section instead of a 1835 subsection of Section 9 1836 o Revised SIP INFO usage and package registration per advice from 1837 Robert Sparks and Paul Kyzivat 1839 17.13. Changes from draft-ietf-06 to draft-ietf-07 1841 o Fixed typo in Acknowledgements 1843 17.14. Changes from draft-ietf-05 to draft-ietf-06 1845 o Added additional security and privacy clarifications regarding 1846 signed and encrypted data 1847 o Additional security and privacy text 1848 o Deleted informative section on ESINets as unnecessary. 1850 17.15. Changes from draft-ietf-04 to draft-ietf-05 1852 o Reworked the security and privacy considerations material in the 1853 document as a whole and in the MIME registation sections of the 1854 MSD and control objects 1855 o Clarified that the element can appear multiple 1856 times within an element 1857 o Fixed IMS definition 1858 o Added clarifying text for the 'msgid' attribute 1860 17.16. Changes from draft-ietf-03 to draft-ietf-04 1862 o Added Privacy Considerations section 1863 o Reworded most uses of non-normative "may", "should", "must", and 1864 "recommended." 1865 o Fixed nits in examples 1867 17.17. Changes from draft-ietf-02 to draft-ietf-03 1869 o Added request to enable cameras 1870 o Improved examples and XML schema 1871 o Clarifications and wording improvements 1873 17.18. Changes from draft-ietf-01 to draft-ietf-02 1875 o Added clarifying text reinforcing that the data exchange is for 1876 small blocks of data infrequently transmitted 1877 o Clarified that dynamic media is conveyed using SIP re-INVITE to 1878 establish a one-way media stream 1879 o Clarified that the scope is the needs of eCall within the SIP 1880 emergency call environment 1881 o Added informative statement that the document may be suitable for 1882 reuse by other ACN systems 1883 o Clarified that normative language for the control block applies to 1884 both IVS and PSAP 1885 o Removed 'ref', 'supported-mime', and elements 1886 o Minor wording improvements and clarifications 1888 17.19. Changes from draft-ietf-00 to draft-ietf-01 1890 o Added further discussion of test calls 1891 o Added further clarification to the document scope 1892 o Mentioned that multi-region vehicles may need to support other 1893 crash notification specifications in addition to eCall 1894 o Added details of the eCall metadata and control functionality 1895 o Added IANA registration for the MIME media type for the control 1896 object 1897 o Added IANA registries for protocol elements and tokens used in the 1898 control object 1899 o Minor wording improvements and clarifications 1901 17.20. Changes from draft-gellens-03 to draft-ietf-00 1903 o Renamed from draft-gellens- to draft-ietf-. 1904 o Added mention of and reference to ETSI TR "Mobile Standards Group 1905 (MSG); eCall for VoIP" 1906 o Added text to Introduction regarding migration/co-existence being 1907 out of scope 1908 o Added mention in Security Considerations that even if the network- 1909 supplied location is just the cell site, this can be useful as a 1910 sanity check on the IVS-supplied location 1911 o Minor wording improvements and clarifications 1913 17.21. Changes from draft-gellens-02 to -03 1915 o Clarifications and editorial improvements. 1917 17.22. Changes from draft-gellens-01 to -02 1919 o Minor wording improvements 1920 o Removed ".automatic" and ".manual" from 1921 "urn:service:test.sos.ecall" registration and discussion text. 1923 17.23. Changes from draft-gellens-00 to -01 1925 o Now using 'EmergencyCallData' for purpose parameter values and 1926 MIME subtypes, in accordance with changes to [RFC7852] 1927 o Added reference to RFC 6443 1928 o Fixed bug that caused Figure captions to not appear 1930 18. References 1932 18.1. Normative References 1934 [msd] CEN, , "Intelligent transport systems -- eSafety -- eCall 1935 minimum set of data (MSD), EN 15722", April 2015. 1937 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1938 Requirement Levels", BCP 14, RFC 2119, 1939 DOI 10.17487/RFC2119, March 1997, 1940 . 1942 [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, 1943 DOI 10.17487/RFC3688, January 2004, 1944 . 1946 [RFC5031] Schulzrinne, H., "A Uniform Resource Name (URN) for 1947 Emergency and Other Well-Known Services", RFC 5031, 1948 DOI 10.17487/RFC5031, January 2008, 1949 . 1951 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 1952 IANA Considerations Section in RFCs", BCP 26, RFC 5226, 1953 DOI 10.17487/RFC5226, May 2008, 1954 . 1956 [RFC6086] Holmberg, C., Burger, E., and H. Kaplan, "Session 1957 Initiation Protocol (SIP) INFO Method and Package 1958 Framework", RFC 6086, DOI 10.17487/RFC6086, January 2011, 1959 . 1961 [RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type 1962 Specifications and Registration Procedures", BCP 13, 1963 RFC 6838, DOI 10.17487/RFC6838, January 2013, 1964 . 1966 [RFC6881] Rosen, B. and J. Polk, "Best Current Practice for 1967 Communications Services in Support of Emergency Calling", 1968 BCP 181, RFC 6881, DOI 10.17487/RFC6881, March 2013, 1969 . 1971 [RFC7303] Thompson, H. and C. Lilley, "XML Media Types", RFC 7303, 1972 DOI 10.17487/RFC7303, July 2014, 1973 . 1975 [RFC7852] Gellens, R., Rosen, B., Tschofenig, H., Marshall, R., and 1976 J. Winterbottom, "Additional Data Related to an Emergency 1977 Call", RFC 7852, DOI 10.17487/RFC7852, July 2016, 1978 . 1980 18.2. Informative references 1982 [CEN] "European Committee for Standardization", 1983 . 1985 [EN_16062] 1986 CEN, , "Intelligent transport systems -- eSafety -- eCall 1987 High Level Application Requirements (HLAP) Using GSM/UMTS 1988 Circuit Switched Networks, EN 16062", April 2015. 1990 [EN_16072] 1991 CEN, , "Intelligent transport systems -- eSafety -- Pan- 1992 European eCall operating requirements, EN 16072", April 1993 2015. 1995 [I-D.ietf-ecrit-car-crash] 1996 Gellens, R., Rosen, B., and H. Tschofenig, "Next- 1997 Generation Vehicle-Initiated Emergency Calls", draft-ietf- 1998 ecrit-car-crash-23 (work in progress), January 2017. 2000 [ITU.X691] 2001 International Telecommunications Union, , "Information 2002 technology -- ASN.1 encoding rules: Specification of 2003 Packed Encoding Rules (PER), ITU-T X.691", July 2002, 2004 . 2007 [MSG_TR] ETSI, , "ETSI Mobile Standards Group (MSG); eCall for 2008 VoIP", ETSI Technical Report TR 103 140 V1.1.1 (2014-04), 2009 April 2014. 2011 [RFC5012] Schulzrinne, H. and R. Marshall, Ed., "Requirements for 2012 Emergency Context Resolution with Internet Technologies", 2013 RFC 5012, DOI 10.17487/RFC5012, January 2008, 2014 . 2016 [RFC5069] Taylor, T., Ed., Tschofenig, H., Schulzrinne, H., and M. 2017 Shanmugam, "Security Threats and Requirements for 2018 Emergency Call Marking and Mapping", RFC 5069, 2019 DOI 10.17487/RFC5069, January 2008, 2020 . 2022 [RFC6443] Rosen, B., Schulzrinne, H., Polk, J., and A. Newton, 2023 "Framework for Emergency Calling Using Internet 2024 Multimedia", RFC 6443, DOI 10.17487/RFC6443, December 2025 2011, . 2027 [RFC7090] Schulzrinne, H., Tschofenig, H., Holmberg, C., and M. 2028 Patel, "Public Safety Answering Point (PSAP) Callback", 2029 RFC 7090, DOI 10.17487/RFC7090, April 2014, 2030 . 2032 [RFC7378] Tschofenig, H., Schulzrinne, H., and B. Aboba, Ed., 2033 "Trustworthy Location", RFC 7378, DOI 10.17487/RFC7378, 2034 December 2014, . 2036 [SDO-3GPP] 2037 "3d Generation Partnership Project", 2038 . 2040 [SDO-ETSI] 2041 "European Telecommunications Standards Institute (ETSI)", 2042 . 2044 [TS22.101] 2045 3GPP, , "3GPP TS 22.101: Technical Specification Group 2046 Services and System Aspects; Service aspects; Service 2047 principles". 2049 [TS23.167] 2050 3GPP, , "3GPP TS 23.167: IP Multimedia Subsystem (IMS) 2051 emergency sessions". 2053 [TS24.229] 2054 3GPP, , "3GPP TS 24.229: IP multimedia call control 2055 protocol based on Session Initiation Protocol (SIP) and 2056 Session Description Protocol (SDP); Stage 3". 2058 Authors' Addresses 2060 Randall Gellens 2061 Core Technology Consulting 2063 Email: rg+ietf@randy.pensive.org 2065 Hannes Tschofenig 2066 Individual 2068 Email: Hannes.Tschofenig@gmx.net 2069 URI: http://www.tschofenig.priv.at