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Checking references for intended status: Informational ---------------------------------------------------------------------------- == Outdated reference: draft-ietf-ecrit-phonebcp has been published as RFC 6881 == Outdated reference: draft-ietf-sipcore-location-conveyance has been published as RFC 6442 == Outdated reference: draft-singh-geopriv-pidf-lo-dynamic has been published as RFC 5962 Summary: 1 error (**), 0 flaws (~~), 4 warnings (==), 2 comments (--). 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: Informational H. Tschofenig 5 Expires: September 9, 2010 Nokia Siemens Networks 6 U. Dietz 7 Vodafone 8 March 8, 2010 10 Best Current Practice for IP-based In-Vehicle Emergency Calls 11 draft-rosen-ecrit-ecall-04.txt 13 Abstract 15 This document describes how to use a subset of the IETF-based 16 emergency call framework for accomplishing emergency calling support 17 in vehicles. Simplifications are possible due to the nature of the 18 functionality that is going to be provided in vehicles with the usage 19 of GPS. Additionally, further profiling needs to be done regarding 20 the encoding of location information. 22 Status of this Memo 24 This Internet-Draft is submitted to IETF in full conformance with the 25 provisions of BCP 78 and BCP 79. 27 Internet-Drafts are working documents of the Internet Engineering 28 Task Force (IETF), its areas, and its working groups. Note that 29 other groups may also distribute working documents as Internet- 30 Drafts. 32 Internet-Drafts are draft documents valid for a maximum of six months 33 and may be updated, replaced, or obsoleted by other documents at any 34 time. It is inappropriate to use Internet-Drafts as reference 35 material or to cite them other than as "work in progress." 37 The list of current Internet-Drafts can be accessed at 38 http://www.ietf.org/ietf/1id-abstracts.txt. 40 The list of Internet-Draft Shadow Directories can be accessed at 41 http://www.ietf.org/shadow.html. 43 This Internet-Draft will expire on September 9, 2010. 45 Copyright Notice 47 Copyright (c) 2010 IETF Trust and the persons identified as the 48 document authors. All rights reserved. 50 This document is subject to BCP 78 and the IETF Trust's Legal 51 Provisions Relating to IETF Documents 52 (http://trustee.ietf.org/license-info) in effect on the date of 53 publication of this document. Please review these documents 54 carefully, as they describe your rights and restrictions with respect 55 to this document. Code Components extracted from this document must 56 include Simplified BSD License text as described in Section 4.e of 57 the Trust Legal Provisions and are provided without warranty as 58 described in the BSD License. 60 Table of Contents 62 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 63 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 64 3. Protocol Profile . . . . . . . . . . . . . . . . . . . . . . . 5 65 4. Data Profile . . . . . . . . . . . . . . . . . . . . . . . . . 8 66 5. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 67 6. Security Considerations . . . . . . . . . . . . . . . . . . . 11 68 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 69 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13 70 9. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 14 71 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15 72 10.1. Normative References . . . . . . . . . . . . . . . . . . 15 73 10.2. Informative references . . . . . . . . . . . . . . . . . 15 74 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17 76 1. Introduction 78 Emergency calls made from vehicles can assist with the objective of 79 significantly reducing road deaths and injuries. Unfortunately, 80 drivers often have a poor location-awareness, especially on urban 81 roads (also during night) and abroad. In the most crucial cases, the 82 victim(s) may not be able to call because they have been injured or 83 trapped. 85 In Europe the European Commission has launched the eCall initiative 86 that may best be described as a user initiated or automatically 87 triggered system to provide notifications to Public Safety Answering 88 Point's (PSAP), by means of cellular communications, that a vehicle 89 has crashed, and to provide geodetic location information and where 90 possible a voice channel to the PSAP. The current specifications 91 being developed to offer the eCall solution are defined to work with 92 circuit switched telephony. This document details how similar or 93 more extended functionality can be accomplished using IP-based 94 mechanisms. 96 This document is organized as follows: Section 2 defines the 97 terminology, Section 3 illustrates the required protocol 98 functionality, Section 4 indicates the required data that has to be 99 transmitted within a PIDF-LO and Section 5 shows an example message 100 exchange. This document concludes with the security considerations 101 in Section 6 and IANA considerations in Section 7. 103 2. Terminology 105 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 106 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 107 document are to be interpreted as described in [1]. 109 This document re-uses a lot of the terminology defined in Section 3 110 of [9]. 112 3. Protocol Profile 114 The usage of in-vehicular emergency calls does not require the usage 115 of a Location Configuration Protocol since GPS is used. Furthermore, 116 since the GPS receiver is permanently turned on it can even provide 117 useful information in cases where the car entered a tunnel. 118 Consequently, there is no need to discover any LIS. 120 Since the emergency call within the car is either triggered by a 121 button or, in most cases, automatically thanks to sensors mounted in 122 the car there is no need to learn a dial string. This document 123 registers a separate Service URN, namely 'urn:service:ecall', used 124 specifically for emergency calls that are triggered by vehicles. 126 The following list provides information about the sections and 127 requires of [2] that are relevant to this specification: 129 Identifying an emergency call: Emergency calls are detected at the 130 end point, i.e., by the vehicle, and the Service URN 131 'urn:service:ecall' MUST be implemented by the end point and 132 recognized by the VSP. The requirements listed in Section 5 of 133 [2] are therefore irrelevant to this specification, as they deal 134 with identifying an emergency call based on dial strings. 136 Location: The encoding of the PIDF-LO [3] is described in Section 4. 137 In an emergency, the end point adds the available location 138 information to the initial SIP INVITE emergency call message. In 139 special cases a location update may be provided, using the 140 procedure described in requirement ED-38 of Section 6.8 of [2]; 141 all other aspects of Section 6.8 from that document are not 142 applicable to this specification. Section 6.2.1, 6.2.2, 6.2.4, 143 6.4, 6.5 and 6.6 of [2] are not applicable to this document. For 144 location conveyance in SIP [4] MUST be used. Further aspects that 145 are not relevant for this document are multiple locations (Section 146 6.9 of [2]), location validation (Section 6.10 of [2]), default 147 location (Section 6.11 of [2]) 149 LoST: Emergency call routing support, for example utilizing LoST, is 150 provided by VSP. As such, the description in Section 8 of [2] is 151 applicable to this document, except for requirement SP-25 and 152 SP-26 regarding legacy devices. 154 Signaling of emergency calls: Section 9 of [2] is applicable to this 155 document with the following exception: ED-60/AN-25 is not 156 applicable as HELD is not used. Video and real-time text may be 157 supported by end device in the future, although currently not 158 envisioned. The corresponding text paragraphs are relevant from 159 Section 9 of [2] when support is being provided. Additionally, 160 ED-62 dealing with "SIP signaling requirements for User Agents" is 161 simplified as follows. The initial SIP signaling method is an 162 INVITE request with the following setting: 164 1. The Request URI MUST be the service URN 'urn:service:ecall'. 166 2. The To header MUST be a service URN 'urn:service:ecall'. 168 3. The From header MUST be present and SHOULD be the AoR of the 169 caller. 171 4. A Via header MUST be present. 173 5. A Contact header MUST be present which MUST be globally 174 routable to permit an immediate call-back to the specific 175 device which placed the emergency call. 177 6. Other headers MAY be included as per normal SIP behavior. 179 7. A Supported header MUST be included with the 'geolocation' 180 option tag [4]. 182 8. The device MUST include location by-value into the call. 184 9. A normal SDP offer SHOULD be included in the INVITE. If 185 voice is supported the offer SHOULD include the G.711 codec, 186 if a voice channel can be established based on the equipment 187 in the car. 189 10. If the device includes location-by-value, the UA MUST support 190 multipart message bodies, since SDP will likely be also in 191 the INVITE. 193 11. The UAC MUST include a "inserted-by=endpoint" header 194 parameter on all Geolocation headers. This informs 195 downstream elements which device entered the location at this 196 URI (either cid-URL or location-by-reference URI). 198 12. SIP Caller Preferences [5] MAY be used to signal how the PSAP 199 should handle the call. For example, a language preference 200 expressed in an Accept-Language header may be used as a hint 201 to cause the PSAP to route the call to a call taker who 202 speaks the requested language. SIP Caller Preferences may 203 also be used to indicate a need to invoke a relay service for 204 communication with people with disabilities in the call. 206 Call backs: The description in Section 10 of [2] is relevant for 207 this document. 209 Mid-call behavior: The description in Section 11 of [2] is fully 210 applicable to this document. 212 Call termination: The description in Section 12 of [2] is fully 213 applicable to this document. 215 Disabling of features: The description in Section 13 of [2] is fully 216 applicable to this document. 218 Media: If hardware and software for real-time text, voice, and video 219 is available in the end device then the requirements regarding 220 multi-media support described in [2] are applicable. 222 Testing: The description in Section 15 of [2] is fully applicable to 223 this document. 225 4. Data Profile 227 Due to the requirement for a built-in GPS receiver only geodetic 228 location information will be sent within an emergency call. 229 Furthermore, the number of location shapes is is restricted. Hence, 230 the following location shapes of [6] MUST be implemented: 2d and 3d 231 Point (see Section 5.2.1 of [6]), Circle (see Section 5.2.3 of [6]), 232 and Ellipsoid (see Section 5.2.7 of [6]). The coordinate reference 233 systems (CRS) specified in [6] are also mandatory for this document. 234 Furthermore, the direction of travel of the vehicle is important for 235 dispatch and hence it MUST be included in the PIDF-LO. The 236 element specified in [7] MUST be supported. 238 5. Example 240 Figure 1 shows an emergency call placed from a vehicle whereby 241 location information information is directly attached to the SIP 242 INVITE message itself. The call is marked as an emergency call using 243 the 'urn:service:ecall' service URN and the PSAP of the VoIP provider 244 determines which PSAP to contact based on the provided location 245 information. As shown in the figure, this route determination may be 246 based on LoST. Then, the emergency call continues towards the PSAP 247 and in this example it hits the ESRP, as the entry point to the PSAP 248 operators emergency services network. Finally, the emergency call 249 will be received by a call taker and first reponders will be 250 dispatched. 252 +--------+ 253 | LoST | 254 | Servers| 255 +--------+ 256 ^ +-------+ 257 | | PSAP2 | 258 | +-------+ 259 v 260 +-------+ +------+ +-------+ 261 Vehicle ------>| Proxy |---->| ESRP |---->| PSAP1 |-----> Call-Taker 262 +-------+ +------+ +-------+ 264 +-------+ 265 | PSAP3 | 266 +-------+ 268 Figure 1: Example of In-Vehicular Emergency Call Message Flow 270 The following example, in Figure 2, shows location information 271 encoded in a PIDF-LO that is being conveyed in such an emergency 272 call. 274 275 280 281 282 283 284 42.5463 -73.2512 285 286 850.24 287 288 289 290 291 270.0 -60.0 292 293 294 295 296 GPS 297 298 299 301 Figure 2: Example of In-Vehicular Emergency Call Message Flow 303 6. Security Considerations 305 This document does not raise security considerations beyond those 306 described in [10]. As with emergency service systems with end host 307 provided location information there is the possibility that that 308 location is incorrect, either intentially (in case of an a denial of 309 service attack against the emergency services infrastructure) or due 310 to a malfunctioning devices. The reader is referred to [11] for a 311 discussion of some of these vulnerabilities. 313 7. IANA Considerations 315 IANA is requested to register the URN 'urn:service:ecall' under the 316 sub-services 'sos' registry defined in Section 4.2 of [8]. 318 urn:service:ecall This service identifier reaches a public safety 319 answering point (PSAP), which in turn dispatches aid appropriate 320 to the emergency related to accidents of vehicles. 322 8. Acknowledgements 324 We would like to thank Michael Montag, Arnoud van Wijk, and Gunnar 325 Hellstroem for their feedback. 327 9. Open Issues 329 While working on this document a few aspects where discovered that 330 require further discussion: 332 o Today's work on the eCall system does not necessarily require a 333 voice call to be established; a voice call may be established 334 whenever possible by the functionality offered by the device. 335 From a protocol mechanims, however, the design for establishing an 336 emergency call including voice and without voice support are 337 somewhat different. Further discussion on the design aspects are 338 needed to align this aspect. 340 o This document currently defines a new service URN to differentiate 341 it from ordinary calls as in-vehicular emergency calls are, in 342 some countries, routed to different PSAPs than regular emergency 343 calls. More thoughts are needed to determine whether this is the 344 best approach. 346 o The current version of the document assumes the usage of LoST at 347 the VSP to perform call routing of the in-vehicular emergency 348 call. This is useful when there are no dial strings need to be 349 learned nor any other service URNs need to be discovered. Further 350 discussion is needed whether additional service URNs might be made 351 available to the vehicle, for example to request roadside 352 assistance or similar services. In that case the option might be 353 provided to run LoST at the end host as well as on the VSP. 355 10. References 357 10.1. Normative References 359 [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement 360 Levels", BCP 14, RFC 2119, March 1997. 362 [2] Rosen, B. and J. Polk, "Best Current Practice for 363 Communications Services in support of Emergency Calling", 364 draft-ietf-ecrit-phonebcp-14 (work in progress), January 2010. 366 [3] Peterson, J., "A Presence-based GEOPRIV Location Object 367 Format", RFC 4119, December 2005. 369 [4] Polk, J. and B. Rosen, "Location Conveyance for the Session 370 Initiation Protocol", draft-ietf-sipcore-location-conveyance-02 371 (work in progress), February 2010. 373 [5] Rosenberg, J., Schulzrinne, H., and P. Kyzivat, "Caller 374 Preferences for the Session Initiation Protocol (SIP)", 375 RFC 3841, August 2004. 377 [6] Winterbottom, J., Thomson, M., and H. Tschofenig, "GEOPRIV 378 Presence Information Data Format Location Object (PIDF-LO) 379 Usage Clarification, Considerations, and Recommendations", 380 RFC 5491, March 2009. 382 [7] Schulzrinne, H., Singh, V., Tschofenig, H., and M. Thomson, 383 "Dynamic Extensions to the Presence Information Data Format 384 Location Object (PIDF-LO)", 385 draft-singh-geopriv-pidf-lo-dynamic-08 (work in progress), 386 March 2010. 388 [8] Schulzrinne, H., "A Uniform Resource Name (URN) for Emergency 389 and Other Well-Known Services", RFC 5031, January 2008. 391 10.2. Informative references 393 [9] Schulzrinne, H. and R. Marshall, "Requirements for Emergency 394 Context Resolution with Internet Technologies", RFC 5012, 395 January 2008. 397 [10] Taylor, T., Tschofenig, H., Schulzrinne, H., and M. Shanmugam, 398 "Security Threats and Requirements for Emergency Call Marking 399 and Mapping", RFC 5069, January 2008. 401 [11] Tschofenig, H., Schulzrinne, H., and B. Aboba, "Trustworthy 402 Location Information", 403 draft-tschofenig-ecrit-trustworthy-location-03 (work in 404 progress), March 2010. 406 Authors' Addresses 408 Brian Rosen 409 NeuStar, Inc. 410 470 Conrad Dr 411 Mars, PA 16046 412 US 414 Phone: 415 Email: br@brianrosen.net 417 Hannes Tschofenig 418 Nokia Siemens Networks 419 Linnoitustie 6 420 Espoo 02600 421 Finland 423 Phone: +358 (50) 4871445 424 Email: Hannes.Tschofenig@gmx.net 425 URI: http://www.tschofenig.priv.at 427 Ulrich Dietz 428 Vodafone 429 Chiemgaustrasse 116 430 Munich 81549 431 Germany 433 Email: Ulrich.Dietz@vodafone.com