RFC8148: Next-Generation Vehicle-Initiated Emergency Calls

Download in PDF format Download in text format

            





Internet Engineering Task Force (IETF)                        R. Gellens
Request for Comments: 8148                    Core Technology Consulting
Category: Standards Track                                       B. Rosen
ISSN: 2070-1721                                            NeuStar, Inc.
                                                           H. Tschofenig
                                                              Individual
                                                                May 2017


           Next-Generation Vehicle-Initiated Emergency Calls

Abstract

   This document describes how to use IP-based emergency services
   mechanisms to support the next generation of emergency calls placed
   by vehicles (automatically in the event of a crash or serious
   incident, or manually invoked by a vehicle occupant) and conveying
   vehicle, sensor, and location data related to the crash or incident.
   Such calls are often referred to as "Automatic Crash Notification"
   (ACN), or "Advanced Automatic Crash Notification" (AACN), even in the
   case of manual trigger.  The "Advanced" qualifier refers to the
   ability to carry a richer set of data.

   This document also registers a MIME media type and Emergency Call
   Data Type for the vehicle, sensor, and location data (often referred
   to as "crash data" even though there is not necessarily a crash) and
   an INFO package to enable carrying this and related data in SIP INFO
   requests.  An external specification for the data format, contents,
   and structure is referenced in this document.

   This document reuses the technical aspects of next-generation Pan-
   European eCall (a mandated and standardized system for emergency
   calls by in-vehicle systems (IVSs) within Europe and other regions).
   However, this document specifies use of a different set of vehicle
   (crash) data, specifically, the Vehicle Emergency Data Set (VEDS)
   rather than the eCall Minimum Set of Data (MSD).  This document is an
   extension of the IETF eCall document, with the primary differences
   being that this document makes the MSD data set optional and VEDS
   mandatory, and it adds attribute values to the metadata/control
   object to permit greater functionality.  This document registers a
   new INFO package (identical to that registered for eCall but with the
   addition of the VEDS MIME type).  This document also describes legacy
   (circuit-switched) ACN systems and their migration to next-generation
   emergency calling, to provide background information and context.







Gellens, et al.              Standards Track                    [Page 1]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc8148.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.























Gellens, et al.              Standards Track                    [Page 2]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   6
   3.  Document Scope  . . . . . . . . . . . . . . . . . . . . . . .   8
   4.  Overview of Legacy Deployment Models  . . . . . . . . . . . .   8
   5.  Migration to Next Generation  . . . . . . . . . . . . . . . .  10
   6.  Vehicle Data  . . . . . . . . . . . . . . . . . . . . . . . .  13
   7.  Data Transport  . . . . . . . . . . . . . . . . . . . . . . .  14
   8.  Call Setup  . . . . . . . . . . . . . . . . . . . . . . . . .  16
   9.  New Metadata/Control Values . . . . . . . . . . . . . . . . .  17
     9.1.  New Values for the "action" Attribute . . . . . . . . . .  18
     9.2.  Example <request> Element . . . . . . . . . . . . . . . .  19
     9.3.  The <ack> Element . . . . . . . . . . . . . . . . . . . .  19
     9.4.  The <capabilities> Element  . . . . . . . . . . . . . . .  20
   10. Test Calls  . . . . . . . . . . . . . . . . . . . . . . . . .  21
   11. Example Call Initiation . . . . . . . . . . . . . . . . . . .  22
   12. Security Considerations . . . . . . . . . . . . . . . . . . .  27
   13. Privacy Considerations  . . . . . . . . . . . . . . . . . . .  28
   14. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  28
     14.1.  MIME Media Type Registration for
            application/EmergencyCall.VEDS+xml . . . . . . . . . . .  28
     14.2.  Registration of the "VEDS" Entry in the Emergency Call
            Data Types Registry  . . . . . . . . . . . . . . . . . .  30
     14.3.  New Action Values  . . . . . . . . . . . . . . . . . . .  30
     14.4.  Emergency Call Static Messages Registry  . . . . . . . .  31
     14.5.  Emergency Call Vehicle Lamp IDs Registry . . . . . . . .  32
     14.6.  Emergency Call Vehicle Camera IDs Registry . . . . . . .  33
     14.7.  The EmergencyCallData.VEDS INFO Package  . . . . . . . .  35
   15. References  . . . . . . . . . . . . . . . . . . . . . . . . .  38
     15.1.  Normative References . . . . . . . . . . . . . . . . . .  38
     15.2.  Informative references . . . . . . . . . . . . . . . . .  39
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  40
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  40

















Gellens, et al.              Standards Track                    [Page 3]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


1.  Introduction

   Emergency calls made by in-vehicle systems (e.g., automatically in
   the event of a crash or serious incident or manually by a vehicle
   occupant) assist in significantly reducing road deaths and injuries
   by allowing emergency services to respond quickly and appropriately
   to the specifics of the incident, often with better location
   accuracy.

   Drivers often have a poor location awareness, especially outside of
   major cities, at night, and when away from home (especially abroad).
   In the most crucial cases, the victim(s) might not be able to call
   because they have been injured or trapped.

   For more than two decades, some vehicles have been equipped with
   telematics systems that, among other features, place an emergency
   call automatically in the event of a crash or manually in response to
   an emergency call button.  Such systems generally have on-board
   location determination systems that make use of satellite-based
   positioning technology, inertial sensors, gyroscopes, etc., which can
   provide an accurate position for the vehicle.  Such built-in systems
   can take advantage of the benefits of being integrated into a
   vehicle, such as more power capacity, ability to have larger or
   specialized antenna, ability to be engineered to avoid or minimize
   degradation by vehicle glass coatings, interference from other
   vehicle systems, etc.  Thus, the Public Safety Answering Point (PSAP)
   can be provided with a good estimate of where the vehicle is during
   an emergency.  Vehicle manufacturers are increasingly adopting such
   systems, both for the safety benefits and for the additional features
   and services they enable (e.g., remote engine diagnostics, remote
   door unlock, stolen vehicle tracking and disabling, etc.).

   A common term for such systems is Automatic Crash Notification (ACN)
   or Advanced Automatic Crash Notification (AACN).  Sometimes the word
   "Collision" is used instead of "Crash."  In this document, "ACN" is
   used as a general term.  ACN systems transmit some amount of data
   specific to the incident, referred to generally as "crash data" (the
   term is commonly used even though there might not have been a crash).
   While different systems transmit different amounts of crash data,
   standardized formats, structures, and mechanisms are needed to
   provide interoperability among systems and PSAPs.

   As of the date of this document, currently deployed in-vehicle
   telematics systems are circuit-switched and lack a standards-based
   ability to convey crash data directly to the PSAP (generally relying
   on either a human advisor or an automated text-to-speech system to
   provide the PSAP call taker with some crash data orally, or in some
   cases via a proprietary mechanism).  In most cases, the PSAP call



Gellens, et al.              Standards Track                    [Page 4]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   taker needs to first realize that the call is related to a vehicle
   incident, and then listen to the data and transcribe it.  Circuit-
   switched ACN systems are referred to here as "CS-ACN".

   The transition to next-generation emergency calling provides an
   opportunity to vastly improve the scope, breadth, reliability, and
   usefulness of crash data by transmitting a standardized set during
   call setup; the data can be processed by the PSAP in an integrated,
   automated way and made available to the call taker at call
   presentation.  It also provides the ability for the call taker to
   request that a vehicle take certain actions, such as flashing lights
   or unlocking doors.  In addition, vehicle manufacturers are provided
   an opportunity to take advantage of the same standardized mechanisms
   for data transmission and request processing for internal use if they
   wish (such as telemetry between the vehicle and a service center for
   both emergency and non-emergency uses, including location-based
   services, multimedia entertainment systems, remote door unlocking,
   remote diagnostics, and roadside assistance applications).

   Next-generation ACN provides an opportunity for such calls to be
   recognized and processed as such during call setup, and routed to an
   equipped PSAP where the vehicle data is available to assist the call
   taker in assessing and responding to the situation.  Next-generation
   (IP-based) ACN systems are referred to here as NG-ACN.

   An ACN call can be initiated by a vehicle occupant or automatically
   initiated by vehicle systems in the event of a serious incident.
   (The "A" in "ACN" does stand for "Automatic", but the term is broadly
   used to refer to the class of calls that are placed by an in-vehicle
   system (IVS) or by Telematics Service Providers (TSPs) and that carry
   incident-related data as well as voice.)  Automatically triggered
   calls indicate a car crash or some other serious incident (e.g., a
   fire).  Manually triggered calls include reports of observed crashes
   or serious hazards (such as impaired drivers or roadway debris),
   requests for medical assistance, etc.

   The Association of Public-Safety Communications Officials (APCO) and
   the National Emergency Number Association (NENA) have jointly
   developed a standardized set of incident-related vehicle data for ACN
   use, called the Vehicle Emergency Data Set (VEDS) [VEDS].  Such data
   is often referred to as crash data although it is applicable in
   incidents other than crashes.

   This document describes how the IETF mechanisms for IP-based
   emergency calls are used to provide the realization of next-
   generation ACN.  Although this specification is designed with the
   requirements for North America ACN in mind (and both APCO and NENA
   are based in the U.S.), it is specified generically such that the



Gellens, et al.              Standards Track                    [Page 5]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   technology can be reused or extended to suit requirements in other
   regions.

   This document reuses the technical aspects of next-generation Pan-
   European eCall (a mandated and standardized system for emergency
   calls by in-vehicle systems within Europe), as described in
   [RFC8147].  However, this document specifies use of a different set
   of vehicle (crash) data, specifically, VEDS rather than the eCall
   Minimum Set of Data (MSD).  This document is an extension of
   [RFC8147], with the differences being that this document makes the
   MSD data set optional and VEDS mandatory, and it adds new attribute
   values to the metadata/control object defined in that document.  This
   document also registers a new INFO package (identical to that defined
   in [RFC8147] with the addition of the VEDS MIME type).

   This document registers the application/EmergencyCallData.VEDS+xml
   MIME media type, the VEDS Emergency Call Data Type, and the
   EmergencyCallData.VEDS INFO package to enable carrying this and
   related data in SIP INFO requests.

   Section 6 introduces VEDS.  Section 7 describes how VEDS data and
   metadata/control blocks are transported within NG-ACN calls.
   Section 8 describes how such calls are placed.

   These mechanisms are used to place emergency calls that are
   identifiable as ACN calls and that carry standardized crash data in
   an interoperable way.

   Calls by in-vehicle systems are placed using cellular networks, which
   might ignore location information sent by an originating device in an
   emergency call INVITE, instead substituting their own location
   information (although often determined in cooperation with the
   originating device).  Standardized crash data structures typically
   include location as determined by the IVS.  A benefit of this is that
   it allows the PSAP to see both the location as determined by the
   cellular network and the location as determined by the IVS.

   This specification inherits the ability to utilize test call
   functionality from Section 15 of [RFC6881].

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].






Gellens, et al.              Standards Track                    [Page 6]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   This document reuses terminology defined in Section 3 of [RFC5012].
   Additionally, we use the following abbreviations:

      3GPP:    3rd Generation Partnership Project

      AACN:    Advanced Automatic Crash Notification

      ACN:     Automatic Crash Notification

      APCO:    Association of Public-Safety Communications Officials

      EENA:    European Emergency Number Association

      ESInet:  Emergency Services IP network

      GNSS:    Global Navigation Satellite System (which includes
               various systems such as the Global Positioning System or
               GPS)

      IVS:     In-Vehicle System

      MNO:     Mobile Network Operator

      MSD:     Minimum Set of Data

      NENA:    National Emergency Number Association

      NG:      Next Generation

      POTS:    Plain Old Telephone Service (normal, circuit-switched
               voice calls)

      PSAP:    Public Safety Answering Point

      TSP:     Telematics Service Provider

      VEDS:    Vehicle Emergency Data Set

   Because the endpoints of a next-generation ACN call are a PSAP and
   either an IVS or a TSP, to avoid repetitively writing "IVS or TSP",
   the term "IVS" is used to represent either an IVS or a TSP when
   discussing signaling behavior (e.g., sending VEDS data, sending a SIP
   INVITE request, receiving a SIP INFO request, etc.).








Gellens, et al.              Standards Track                    [Page 7]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


3.  Document Scope

   This document is focused on how an ACN emergency call is set up and
   incident-related data (including vehicle, sensor, and location data)
   is transmitted to the PSAP using IETF specifications.  For the direct
   model, this is the end-to-end description (between the vehicle and
   the PSAP).  For the TSP model, this describes the call leg between
   the TSP and the PSAP, leaving the call leg between the vehicle and
   the TSP up to the entities involved (i.e., IVS and TSP vendors) who
   are free to use the same mechanism for both legs, or not.

   Note that Europe has a mandated and standardized system for emergency
   calls by in-vehicle systems.  This Pan-European system is known as
   "eCall" and is the subject of a separate document, [RFC8147], which
   this document builds on.  Vehicles designed to operate in multiple
   regions might need to support eCall as well as NG-ACN as described
   here.  A vehicle IVS might determine whether to use eCall or ACN by
   first determining the region or country in which it is located (e.g.,
   from a GNSS location estimate and/or identity of or information from
   an MNO).  If other regions adopt other data formats, a multi-region
   vehicle might need to support those as well.  This document adopts
   the call setup and other technical aspects of [RFC8147], which uses
   [RFC7852]; this makes it straightforward to use a different data set
   while keeping other technical aspects unchanged.  Hence, both next-
   generation eCall (NG-eCall) and the NG-ACN mechanism described here
   are compatible, differing primarily in the specific data block that
   is sent (the eCall MSD in the case of NG-eCall and VEDS in this
   document) and some additions to the metadata/control data block.  If
   other regions adopt their own vehicle data sets, this can be
   similarly accommodated without changing other technical aspects.
   Note that any additional data formats require a new INFO package to
   permit transport within SIP INFO requests.

4.  Overview of Legacy Deployment Models

   Legacy (circuit-switched) systems for placing emergency calls by
   in-vehicle systems generally have some ability to convey at least
   location and in some cases telematics data to the PSAP.  Most such
   systems use one of three architectural models, which are described
   here as: "TSP", "direct", and "paired".  These three models are
   illustrated below.

   In the TSP model, both emergency and routine TSP service calls are
   placed to a TSP; a proprietary technique (e.g., a proprietary in-band
   modem) is used for data transfer between the TSP and the vehicle.






Gellens, et al.              Standards Track                    [Page 8]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   In an emergency, typically a TSP agent verifies the emergency,
   bridges in the PSAP, and communicates location, crash data (such as
   impact severity and trauma prediction), and other data (such as the
   vehicle description) to the PSAP call taker orally (in some cases, a
   proprietary out-of-band interface is used).  Since the TSP knows the
   location of the vehicle (from on-board GNSS and sensors), location-
   based routing is usually used to route to the appropriate PSAP.  In
   some cases, the TSP is able to transmit location automatically, using
   similar techniques as for wireless calls.  A three-way voice call is
   generally established between the vehicle, the TSP, and the PSAP,
   allowing communication between the PSAP call taker, the TSP agent,
   and the vehicle occupants (who might be unconscious).

      ///----\\\  proprietary  +-----+  911 trunk or POTS   +------+
     ||| IVS |||-------------->| TSP |--------------------->| PSAP |
      \\\----///  crash data   +-----+  location via trunk  +------+

                        Figure 1: Legacy TSP Model

   In the paired model, the IVS uses a local link (typically Bluetooth
   [Bluetooth]) with a previously paired handset to establish an
   emergency call with the PSAP (by dialing a standard emergency number;
   9-1-1 in North America) and then communicates location data to the
   PSAP via text-to-speech; crash data might or might not be conveyed
   also using text-to-speech.  Some such systems use an automated voice
   prompt menu for the PSAP call taker (e.g., "this is an automatic
   emergency call from a vehicle; press 1 to open a voice path to the
   vehicle; press 2 to hear the location read out") to allow the call
   taker to request location data via text-to-speech.

      ///----\\\   +----+   911/etc. voice call via handset  +------+
     ||| IVS |||-->| HS |----------------------------------->| PSAP |
      \\\----///   +----+   location via text-to-speech      +------+

   (Note: "HS" is handset.)

                       Figure 2: Legacy Paired Model

   In the direct model, the IVS directly places an emergency call with
   the PSAP by dialing a standard emergency number (9-1-1 in North
   America).  Such systems might communicate location data to the PSAP
   via text-to-speech; crash data might or might not be conveyed using
   text-to-speech.  Some such systems use an automated voice prompt menu
   (e.g., "this is an automatic emergency call from a vehicle; press 1
   to open a voice path to the vehicle; press 2 to hear the location
   read out") to allow the call taker to request location data via
   text-to-speech.




Gellens, et al.              Standards Track                    [Page 9]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


      ///----\\\      911/etc. voice call via IVS         +------+
     ||| IVS  |||---------------------------------------->| PSAP |
      \\\----///     location via text-to-speech          +------+

                       Figure 3: Legacy Direct Model

5.  Migration to Next Generation

   The migration of emergency calls placed by in-vehicle systems to
   next-generation (all-IP) technology per this document provides a
   standardized mechanism to identify such calls and to convey crash
   data with the call setup, as well as enabling additional
   communications modalities and enhanced functionality.  This allows
   ACN calls and crash data to be automatically processed by the PSAP
   and made available to the call taker in an integrated, automated way.
   Because the crash data is carried in the initial SIP INVITE (per
   [RFC7852]) the PSAP can present it to the call taker simultaneously
   with the appearance of the call.  The PSAP can also process the data
   to take other actions (e.g., if multiple calls from the same location
   arrive when the PSAP is busy and a subset of them are NG-ACN calls, a
   PSAP might choose to store the information and reject the calls,
   since the IVS will receive confirmation that the information has been
   successfully received; a PSAP could also choose to include a message
   stating that it is aware of the incident and responders are on the
   way, and a PSAP could call the vehicle back when a call taker is
   available).

   The migration of origination devices and networks, PSAPs, emergency
   services networks, and other telephony environments to next
   generation technology provides enhanced interoperability and
   functionality, especially for emergency calls carrying additional
   data such as vehicle crash data.  (In the U.S., a network
   specifically for emergency responders is being developed.  This
   network, FirstNet, will be next generation from the start, enhancing
   the ability for data exchange between PSAPs and responders.)

   NG-ACN calls can be recognized as such during call set-up; they can
   be routed to a PSAP that is prepared both technically and
   operationally to handle such calls, and the vehicle-determined
   location and crash data can be processed automatically by the PSAP
   and made available to the call taker simultaneously with the call
   appearance.  Enhanced functionality includes the ability for the PSAP
   call taker to request the vehicle to take an action, such as sending
   an updated set of data, conveying a message to the occupants,
   flashing lights, unlocking doors, etc.






Gellens, et al.              Standards Track                   [Page 10]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   Vehicle manufacturers using the TSP model can choose to take
   advantage of the same mechanism to carry telematics data and requests
   and responses between the vehicle and the TSP for both emergency and
   non-emergency calls as are used for the interface with the PSAP.

   An IVS establishes a next-generation emergency call (see [RFC6443]
   and [RFC6881]) with an initial INVITE containing a Request-URI
   indicating an ACN emergency call and Call-Info header fields
   indicating that both vehicle crash and capabilities data are
   included; the IVS typically does not perform routing or location
   queries (relying on the MNO for this).

   [RFC8147] registers new service URN children within the "sos"
   subservice.  These URNs request NG-ACN resources and differentiate
   between manually and automatically triggered NG-ACN calls (which
   might be subject to different treatment depending on policy).  The
   two service URNs registered in [RFC8147] are
   "urn:service:sos.ecall.automatic" and "urn:service:sos.ecall.manual".
   The same service URNs are used for ACN as for eCall since in any
   region only one of these is supported, making a distinction
   unnecessary.  (Further, PSAP equipment might support multiple data
   formats, allowing a PSAP to handle a vehicle that erroneously sent
   the wrong data object.)

   Note that in North America, routing queries performed by clients
   outside of an ESInet typically treat all sub-services of "sos"
   identically to "sos" with no sub-service.  However, the Request-URI
   header field retains the full sub-service; route and handling
   decisions within an ESInet or PSAP can take the sub-service into
   account.  For example, in a region with multiple cooperating PSAPs,
   an NG-ACN call might be routed to a PSAP that is NG-ACN capable, or
   one that specializes in vehicle-related incidents.

   Migration of the three architectural models to next generation
   (all-IP) is described below.

   In the TSP model, the IVS transmits crash and location data to the
   TSP either by reusing the mechanisms and data objects described in
   this document or by using a proprietary mechanism.  In an emergency,
   the TSP bridges in the PSAP, and the TSP transmits crash and other
   data to the PSAP using the mechanisms and data objects described in
   this document.  There is a three-way call between the vehicle, the
   TSP, and the PSAP, allowing communication between the PSAP call
   taker, the TSP agent, and the vehicle occupants (who might be
   unconscious).  The TSP relays PSAP requests and vehicle responses.






Gellens, et al.              Standards Track                   [Page 11]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


                   proprietary
     ///----\\\    or standard     +-----+     standard       +------+
    ||| IVS |||------------------->| TSP |------------------->| PSAP |
     \\\----///  crash+other data  +-----+  crash+other data  +------+

                    Figure 4: Next-Generation TSP Model

   The vehicle manufacturer and the TSP can choose to use the same
   mechanisms and data objects on the left call leg in Figure 4 as on
   the right.  (Note that the TSP model can be more difficult when the
   vehicle is in a different country than the TSP (e.g., a US resident
   driving in Canada) because of the additional complexity in choosing
   the correct PSAP based on vehicle location performed by a TSP in a
   different country.)

   In the direct model, the IVS communicates crash data to the PSAP
   directly using the mechanisms and data objects described in this
   document.

     ///----\\\           NG emergency call              +------+
    ||| IVS |||----------------------------------------->| PSAP |
     \\\----///          crash + other data              +------+

                  Figure 5: Next-Generation Direct Model

   In the paired model, the IVS uses a local link to a previously paired
   handset to establish an emergency call with the PSAP; it is unclear
   what facilities are or will be available for transmitting crash data
   through the link to the handset for inclusion in an NG emergency call
   and receiving additional data items from the response.  Hence,
   manufacturers that use the paired model for legacy calls might choose
   to adopt either the direct or TSP model for next-generation calls.

      ///----\\\   (undefined)    +----+      standard        +------+
     ||| IVS |||----------------->| HS |--------------------->| PSAP |
      \\\----///   (undefined)    +----+  crash + other data  +------+

                  Figure 6: Next-Generation Paired Model

   Regardless of model, if the call is routed to a PSAP that is not
   NG-ACN capable, the PSAP ignores (or does not receive) the vehicle
   data.  This is detectable by the IVS or TSP when the status response
   to the INVITE (e.g., 200 OK) lacks a metadata/control structure
   acknowledging receipt of the data [RFC8147].  The IVS or TSP then
   proceeds as it would for a CS-ACN call (e.g., oral conveyance of
   data).





Gellens, et al.              Standards Track                   [Page 12]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


6.  Vehicle Data

   APCO and NENA have jointly developed a standardized set of incident-
   related vehicle data for ACN use, called the Vehicle Emergency Data
   Set (VEDS) [VEDS].  Such data is often referred to as crash data
   although it is applicable in incidents other than crashes.

   VEDS provides a standard data set for the transmission, exchange, and
   interpretation of vehicle-related data.  A standard data format
   allows the data to be generated by an IVS or TSP and interpreted by
   PSAPs, emergency responders, and medical facilities.  It includes
   incident-related information such as airbag deployment, location and
   compass orientation of the vehicle, spatial orientation of the
   vehicle (e.g., upright, on a side, roof, or bumper), sensor data that
   can indicate the potential severity of the crash and the likelihood
   of severe injuries to the vehicle occupants, etc.  This data better
   informs the PSAP and emergency responders as to the type of response
   that might be needed.  Some of this information has been included in
   U.S. government guidelines for field triage of injured patients
   [triage-2008] [triage-2011].  These guidelines are designed to help
   responders identify the potential existence of severe internal
   injuries and to make critical decisions about how and where a patient
   needs to be transported.

   VEDS is an XML structure (see [VEDS]) transported in SIP using the
   application/EmergencyCallData.VEDS+xml MIME media type.

   If new data blocks are needed (e.g., in other regions or for enhanced
   data), the steps required during standardization are briefly
   summarized below:

   o  A set of data is standardized by a Standards Development
      Organization (SDO) or appropriate organization.

   o  A MIME media type for the crash data set is registered with IANA

      *  If the data is specifically for use in emergency calling, the
         MIME media type is normally under the application type with a
         subtype starting with EmergencyCallData.

      *  If the data format is XML, then by convention the name has a
         suffix of "+xml".









Gellens, et al.              Standards Track                   [Page 13]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   o  The item is registered in the "Emergency Call Data Types"
      registry, as defined in Section 11.1.9 of [RFC7852].

      *  For emergency-call-specific formats, the registered name is the
         root of the MIME media type (not including the
         EmergencyCallData prefix and any suffix such as "+xml") as
         described in Section 4.1 of [RFC7852].

   o  A new INFO package is registered that permits carrying the new
      media type, the metadata/control object (defined in [RFC8147]),
      and for compatibility, the MSD and VEDS objects, in SIP INFO
      requests.

7.  Data Transport

   [RFC7852] establishes a general mechanism for including blocks of
   data within a SIP emergency call.  This document makes use of that
   mechanism.  This document also registers an INFO package (in
   Section 14.7) to enable NG-ACN-related data blocks to be carried in
   SIP INFO requests (per [RFC6086], new SIP INFO method usages require
   the definition of an INFO package).

   VEDS is an XML structure defined by APCO and NENA [VEDS].  It is
   carried in a body part with MIME media type application/
   EmergencyCallData.VEDS+xml.

   An IVS transmits a VEDS data block (see [VEDS]) by including it as a
   body part of a SIP message per [RFC7852].  The body part is
   identified by its MIME media type (application/
   EmergencyCallData.VEDS+xml) in the Content-Type header field of the
   body part.  The body part is assigned a unique identifier that is
   listed in a Content-ID header field in the body part.  The SIP
   message is marked as containing the VEDS data by adding (or appending
   to) a Call-Info header field at the top level of the SIP message.
   This Call-Info header field contains a Content Identifier (CID) URL
   referencing the body part's unique identifier and a "purpose"
   parameter identifying the data as a VEDS data block per the
   "Emergency Call Data Types" registry entry; the "purpose" parameter's
   value is "EmergencyCallData.VEDS".  A VEDS data block is carried in a
   SIP INFO request by using the INFO package defined in Section 14.7.

   A PSAP or IVS transmits a metadata/control object (see [RFC8147]) by
   including it in a SIP message as a MIME body part per [RFC7852].  The
   body part is identified by its MIME media type (application/
   EmergencyCallData.Control+xml) in the Content-Type header field of
   the body part.  The body part is assigned a unique identifier that is
   listed in a Content-ID header field in the body part.  The SIP
   message is marked as containing the metadata/control block by adding



Gellens, et al.              Standards Track                   [Page 14]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   (or appending to) a Call-Info header field at the top level of the
   SIP message.  This Call-Info header field contains a CID URL
   referencing the body part's unique identifier and a "purpose"
   parameter identifying the data as a metadata/control block per the
   "Emergency Call Data Types" registry entry; the "purpose" parameter's
   value is "EmergencyCallData.Control".  A metadata/control object is
   carried in a SIP INFO request by using the INFO package defined in
   Section 14.7.

   A body part containing a VEDS or metadata/control object has a
   Content-Disposition header field value containing "By-Reference" and
   is always enclosed in a multipart body part (even if it would
   otherwise be the only body part in the SIP message).

   An IVS initiating an NG-ACN call includes in the initial INVITE a
   VEDS data block and a metadata/control object informing the PSAP of
   its capabilities.  The VEDS and metadata/control body parts (and
   Presence Information Data Format Location Object (PIDF-LO)) have a
   Content-Disposition header field with the value "By-Reference;
   handling=optional".  Specifying handling=optional prevents the INVITE
   from being rejected if it is processed by a legacy element (e.g., a
   gateway between SIP and circuit-switched environments) that does not
   understand the VEDS or metadata/control (or PIDF-LO) objects.  The
   PSAP creates a metadata/control object acknowledging receipt of the
   VEDS data and includes it in the SIP final response to the INVITE.
   The metadata/control object is not included in provisional (e.g.,
   180) responses.

   If the IVS receives an acknowledgment for a VEDS data object with
   received=false, this indicates that the PSAP was unable to properly
   decode or process the VEDS.  The IVS action is not defined (e.g., it
   might only log an error).  Since the PSAP is able to request an
   updated VEDS during the call, if an initial VEDS is unsatisfactory in
   any way, the PSAP can choose to request another one.

   A PSAP can request that the vehicle send an updated VEDS data block
   during a call.  To do so, the PSAP creates a metadata/control object
   requesting VEDS data and includes it as a body part of a SIP INFO
   request sent within the dialog.  The IVS then includes an updated
   VEDS data object as a body part of a SIP INFO request and sends it
   within the dialog.  If the IVS is unable to send the VEDS for any
   reason, it instead sends a metadata/control object containing an
   <ack> element acknowledging the request and containing an
   <actionResult> element with the "success" parameter set to "false"
   and a "reason" parameter (and optionally a "details" parameter)
   indicating why the request cannot be accomplished.  Per [RFC6086],
   metadata/control objects and VEDS data are sent using the INFO
   package defined in Section 14.7.  In addition, to align with the way



Gellens, et al.              Standards Track                   [Page 15]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   a VEDS or metadata/control block is transmitted in a SIP message
   other than a SIP INFO request, one or more Call-Info header fields
   are included in the SIP INFO request referencing the VEDS or
   metadata/control block.  See Section 14.7 for more information on the
   use of SIP INFO requests within NG-ACN calls.

   Any metadata/control object sent by a PSAP can request that the
   vehicle perform an action (such as sending a data block, flashing
   lights, providing a camera feed, etc.).  The IVS sends an
   acknowledgment for any request other than a successfully executed
   send-data action.  Multiple requests with the same "action:" value
   MUST be sent in separate metadata/control body parts (to avoid any
   ambiguity in the acknowledgment).  For each metadata/control block
   received containing one or more <request> elements (except for
   successfully executed send-data requests), the IVS sends a metadata/
   control object containing an <ack> element acknowledging the received
   metadata/control block, containing an <actionResult> element per
   <request> element.

   If the IVS is aware that VEDS data it sent previously has changed, it
   MAY send an unsolicited VEDS in any convenient SIP message, including
   a SIP INFO request during the call.  The PSAP sends an acknowledgment
   for an unsolicited VEDS object; if the IVS sent the unsolicited VEDS
   in a SIP INFO request, the acknowledgment is sent in a new SIP INFO
   request; otherwise, it is sent in the reply to the SIP request
   containing the VEDS.

8.  Call Setup

   An IVS initiating an NG-ACN call sends a SIP INVITE request using one
   of the SOS sub-services "SOS.ecall.automatic" or "SOS.ecall.manual"
   in the Request-URI.  This SIP INVITE request includes standard sets
   of both crash and capabilities data as described in Section 7.

   Entities along the path between the vehicle and the PSAP are able to
   identify the call as an ACN call and handle it appropriately.  The
   PSAP is able to identify the crash and capabilities data included in
   the SIP INVITE request by examining the Call-Info header fields for
   "purpose" parameters whose values start with EmergencyCallData.  The
   PSAP is able to access the data it is capable of handling and is
   interested in by checking the "purpose" parameter values.

   This document extends [RFC8147] by reusing the call setup and other
   normative requirements with the exception that in this document,
   support for the eCall MSD is OPTIONAL and support for VEDS is
   REQUIRED.  This document also adds new attribute values to the
   metadata/control object defined in [RFC8147].




Gellens, et al.              Standards Track                   [Page 16]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


9.  New Metadata/Control Values

   This document adds new attribute values to the metadata/control
   structure defined in [RFC8147].

   In addition to the base usage from the PSAP to the IVS to acknowledge
   receipt of crash data, the <ack> element is also contained in a
   metadata/control block sent by the IVS to the PSAP.  This is used by
   the IVS to acknowledge receipt of a request by the PSAP and indicate
   if the request was carried out when that request would not otherwise
   be acknowledged (if the PSAP requests the vehicle to send data and
   the vehicle does so, the data serves as a success acknowledgment);
   see Section 8 for details.

   The <capabilities> element is used in a metadata/control block sent
   from the IVS to the PSAP (e.g., in the initial INVITE) to inform the
   PSAP of the vehicle capabilities.  Child elements contain all actions
   and data types supported by the vehicle and all available lamps
   (lights) and cameras.

   New request values are added to the <request> element to enable the
   PSAP to request the vehicle to perform additional actions.

   Mandatory Actions (the IVS and the PSAP MUST support):

   o  Transmit data object (VEDS MUST be supported; MSD MAY be
      supported)

   Optional Actions (the IVS and the PSAP MAY support):

   o  Display and/or play static (pre-defined) message
   o  Display and/or speak dynamic text (text supplied in action)
   o  Flash or turn on or off a lamp (light)
   o  Honk horn
   o  Lock or unlock doors
   o  Enable a camera

   The <ack> element indicates the object being acknowledged (i.e., a
   data object or a metadata/control block containing <request>
   elements) and reports success or failure.

   The <capabilities> element has child <request> elements indicating
   the actions (including data types, lamps (lights), and cameras)
   supported by the IVS.

   The <request> element contains attributes to indicate the request and
   to supply any needed information, and it MAY contain a <text> child
   element to contain the text for a dynamic message.  The "action"



Gellens, et al.              Standards Track                   [Page 17]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   attribute is mandatory and indicates the specific action.  [RFC8147]
   established an IANA registry to contain the allowed values; this
   document adds new values to that registry in Table 1.

9.1.  New Values for the "action" Attribute

   The following new "action" values are defined:

   msg-static:  displays or plays a pre-defined message (translated as
      appropriate for the language of the vehicle's interface).  A
      registry is created in Section 14.4 for messages and their IDs.
      Vehicles include the highest registered message in their
      <capabilities> element to indicate support for all messages up to
      and including the indicated value.  A registry of message
      identification values is defined in Section 14.4.  There is only
      one static message initially defined (listed in Table 2).  Because
      all compliant vehicles are expected to support all static messages
      translated into all languages supported by the vehicle, it is
      important to limit the number of such messages.  Therefore, this
      registry operates under "Specification Required" rules as defined
      in [RFC5226], which requires a stable, public document and implies
      expert review of the publication.

   msg-dynamic:  displays or speaks (via text-to-speech) a message
      contained in a child <text> element within the request.

   honk:  sounds the horn.

   lamp:  flashes a lamp (light) or turns it on or off.  The lamp is
      identified by a lamp ID token contained in an "element-id"
      attribute of the request.  The desired state of the lamp is either
      "on", "off", or "flash" as indicated in a "requested-state"
      attribute.  The duration of the lamp's requested state is
      specified in a "persistence" attribute.  A registry of lamp
      identification values is defined in Section 14.5.  The initial
      values (listed in Table 3) are head, interior, fog-front,
      fog-rear, brake, brake-center, position-front, position-rear,
      turn-left, turn-right, and hazard.

   enable-camera:  adds a one-way media stream (established via SIP
      re-INVITE sent by the vehicle) to enable the PSAP call taker to
      view a feed from a camera.  A registry of camera identification
      values is defined in Section 14.6.  The initial values (listed in
      Table 4) are backup, left-rear, right-rear, forward, rear-wide,
      lane, interior, night-front, night-rear, night-left, and night-
      right.





Gellens, et al.              Standards Track                   [Page 18]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   door-lock:  locks or unlocks all door locks.  A "requested-state"
      attribute contains either "locked" or "unlocked" to indicate if
      the doors are to be locked or unlocked.

   Note that there is no "request" action to play dynamic media (such as
   an audio message).  The PSAP can send a SIP re-INVITE to establish a
   one-way media stream for this purpose.

9.2.  Example <request> Element

       <?xml version="1.0" encoding="UTF-8"?>
       <EmergencyCallData.Control
           xmlns="urn:ietf:params:xml:ns:EmergencyCallData:control"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

       <request action="send-data" datatype="VEDS"/>
       <request action="lamp" element-id="hazard"
                requested-state="flash" persistence="PT1H"/>
       <request action="msg-static" int-id="1"/>
       <request action="msg-dynamic">
           <text>Remain calm.  Help is on the way.</text>
       </request>

       </EmergencyCallData.Control>

                        Figure 7: <request> Example

9.3.  The <ack> Element

   The <ack> element is transmitted by the PSAP to acknowledge
   unsolicited data sent by the IVS and transmitted by the IVS to
   acknowledge receipt of a <request> element other than a successfully
   performed "send-data" request (e.g., a request to display a message
   to the vehicle occupants is acknowledged, but a request to transmit
   VEDS data is not, since the transmitted VEDS serves as
   acknowledgment).  An <ack> element sent by an IVS references the
   unique ID of the metadata/control object containing the request(s),
   and for each request being acknowledged, it indicates whether the
   request was successfully performed, and if not, it indicates why not.












Gellens, et al.              Standards Track                   [Page 19]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


9.3.1.  Examples of the <ack> Element

       <?xml version="1.0" encoding="UTF-8"?>
       <EmergencyCallData.Control
           xmlns="urn:ietf:params:xml:ns:EmergencyCallData:control"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

       <ack ref="1234567890@atlanta.example.com">
           <actionResult action="msg-dynamic" success="true"/>
           <actionResult action="lamp" success="false" reason="unable"
                         details="The requested lamp is inoperable"/>
       </ack>

       </EmergencyCallData.Control>

                 Figure 8: Example <ack> from IVS to PSAP

9.4.  The <capabilities> Element

   The <capabilities> element [RFC8147] is transmitted by the IVS to
   indicate its capabilities to the PSAP.

   The <capabilities> element contains a <request> child element per
   action supported by the vehicle.  The vehicle MUST support sending
   the VEDS data object and so includes at a minimum a <request> child
   element with the "action" attribute set to "send-data" and the
   "supported-values" attribute containing all data blocks supported by
   the IVS, which MUST include "VEDS".  All other actions are OPTIONAL.

   If the "msg-static" action is supported, a <request> child element
   with the "action" attribute set to "msg-static" is included, with the
   "int-id" attribute set to the highest supported static message
   supported by the vehicle.  A registry is created in Section 14.4 to
   map "int-id" values to static text messages.  By sending the highest
   supported static message number in its <capabilities> element, the
   vehicle indicates its support for all static messages in the registry
   up to and including that value.

   If the "lamp" action is supported, a <request> child element with the
   "action" attribute set to "lamp" is included, with the "supported-
   values" attribute set to all supported lamp IDs.  A registry is
   created in Section 14.5 to contain lamp ID values.

   If the "enable-camera" action is supported, a <request> child element
   with the "action" attribute set to "enable-camera" is included, with
   the "supported-values" attribute set to all supported camera IDs.  A
   registry is created in Section 14.6 to contain camera ID values.




Gellens, et al.              Standards Track                   [Page 20]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


9.4.1.  Example <capabilities> Element

       <?xml version="1.0" encoding="UTF-8"?>
       <EmergencyCallData.Control
           xmlns="urn:ietf:params:xml:ns:EmergencyCallData:control"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

       <capabilities>
           <request action="send-data" supported-values="VEDS"/>
           <request action="lamp"
                    supported-values="head;interior;fog-front;
                    fog-rear;brake;position-front;position-rear;
                    turn-left;turn-right;hazard"/>
           <request action="msg-static" int-id="3"/>
           <request action="msg-dynamic"/>
           <request action="honk"/>
           <request action="enable-camera"
                    supported-values="backup; interior"/>
           <request action="door-lock"/>
       </capabilities>

       </EmergencyCallData.Control>

                     Figure 9: <capabilities> Example

10.  Test Calls

   An NG-ACN test call is a call that is recognized and treated to some
   extent as an NG-ACN call but is not given emergency call treatment
   nor handled by a PSAP call taker.  The specific handling of test
   NG-ACN calls is outside the scope of this document; typically, the
   test call facility allows the IVS, user, or TSP to verify that an
   NG-ACN call can be successfully established with voice and/or other
   media communication.  The IVS might also be able to verify that the
   crash data was successfully received.

   This document builds on [RFC8147], which inherits the ability to
   utilize test call functionality from Section 15 of [RFC6881].  A
   service URN starting with "test." indicates a test call.  Per
   [RFC8147], "urn:service:test.sos.ecall" is used for test NG-ACN
   calls.

   MNOs, emergency authorities, ESInets, and PSAPs handle a vehicle call
   requesting the "test" service URN so that the desired functionality
   is tested, but this is outside the scope of this document.  (One
   possibility is that MNOs route such calls as non-emergency calls to
   an ESInet, which routes them to a PSAP that supports NG-ACN calls;
   the PSAP accepts test calls, sends a crash data acknowledgment, and



Gellens, et al.              Standards Track                   [Page 21]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   plays an audio clip (for example, saying that the call reached an
   appropriate PSAP and the vehicle data was successfully processed) in
   addition to supporting media loopback per [RFC6881].)

   Note that since test calls are placed using "test" as the parent
   service URN and "sos" as a child, such calls are not treated as an
   emergency call, so some functionality might not apply (such as
   preemption or availability for devices lacking service
   ("non-service-initialized" (NSI) devices) if those are available for
   emergency calls).

11.  Example Call Initiation

   Figure 10 shows an NG-ACN call initiation.  The vehicle initiates an
   NG-ACN call using an MNO.  The MNO routes the call to an ESInet, as
   for any emergency call.  The ESInet routes the call to an appropriate
   NG-ACN-capable PSAP (using location information and the fact that it
   is an NG-ACN call).  The call is processed by the Emergency Services
   Routing Proxy (ESRP), as the entry point to the ESInet.  The ESRP
   routes the call to an appropriate NG-ACN-capable PSAP, where the call
   is handled by a call taker.  (In deployments where there is no
   ESInet, the MNO itself routes the call directly to an appropriate
   NG-ACN-capable PSAP.)

                               +---------------------------------------+
                               |                                       |
               +------------+  |                  +-------+            |
               |            |  |                  | PSAP2 |            |
               |            |  |                  +-------+            |
               | Originating|  |                                       |
               |   Mobile   |  |  +------+    +----------------------+ |
     Vehicle-->|   Network  |--|->| ESRP |--->| PSAP1 --> Call Taker | |
               |            |  |  +------+    +----------------------+ |
               |            |  |                                       |
               +------------+  |                  +-------+            |
                               |                  | PSAP3 |            |
                               |                  +-------+            |
                               |                                       |
                               |                                       |
                               |                                       |
                               |                ESInet                 |
                               +---------------------------------------+

                    Figure 10: Example Call Initiation

   Figure 11 illustrates an example SIP emergency call INVITE request as
   generated by the IVS.  It includes a PIDF-LO with vehicle-determined
   location information, a VEDS block with crash data, and a metadata/



Gellens, et al.              Standards Track                   [Page 22]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   control block with capabilities data.  The INVITE has a request URI
   containing the urn:service:sos.ecall.automatic service URN.  For
   brevity, the example VEDS block does not show VEDS location
   information, although this is generally present.

   The example VEDS data structure shows information about a crashed
   vehicle.  The example communicates that the car is a model year 2015
   Saab 9-5 (a car that does not exist).  The front airbag deployed as a
   consequence of the crash.  The <VehicleBodyCategoryCode> indicates
   that the crashed vehicle is a passenger car (the code is set to
   "101") and that it is not a convertible (the <ConvertibleIndicator>
   value is set to "false").

   The <VehicleCrashPulse> element provides further information about
   the crash, namely that the force of impact based on the change in
   velocity over the duration of the crash pulse was 100 MPH.  The
   principal direction of the force of the impact is set to "12" (which
   refers to 12 o'clock, corresponding to a frontal collision).  This
   value is in the <CrashPulsePrincipalDirectionOfForceValue> element.

   The <CrashPulseRolloverQuarterTurnsValue> indicates the number of
   quarter turns in concert with a rollover expressed as a number; in
   our case 1.

   No roll bar was deployed, as indicated in
   <VehicleRollbarDeployedIndicator> being set to "false".

   Next, there is information indicating seat belt and seat sensor data
   for individual seat positions in the vehicle.  In our example,
   information from the driver seat is available (value "1" in the
   <VehicleSeatLocationCategoryCode> element) showing that the seat belt
   was monitored (<VehicleSeatbeltMonitoredIndicator> element), the seat
   belt was fastened (<VehicleSeatbeltFastenedIndicator> element), and
   the seat sensor determined that the seat was occupied
   (<VehicleSeatOccupiedIndicator> element).

   The weight of the vehicle when empty is listed as 600 kilograms in
   our example.

   The <SevereInjuryIndicator> element is set to "true", indicating a
   likelihood that a vehicle occupant has suffered a severe injury
   requiring immediate trauma care.

   Additional information is provided, including the presence of fuel
   leakage (<FuelLeakingIndicator> element), an indication whether the
   vehicle was subjected to multiple impacts (<MultipleImpactsIndicator>
   element), the orientation of the vehicle at final rest
   (<VehicleFinalRestOrientationCategoryCode> element), and an



Gellens, et al.              Standards Track                   [Page 23]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   indication that no parts of the vehicle are currently detected as
   being on fire (the <VehicleFireIndicator> element).

     INVITE urn:service:sos.ecall.automatic SIP/2.0
     To: urn:service:sos.ecall.automatic
     From: <sip:+13145551111@example.com>;tag=9fxced76sl
     Call-ID: 3848276298220188511@atlanta.example.com
     Geolocation: <cid:target123@example.com>
     Geolocation-Routing: no
     Call-Info: <cid:1234567890@atlanta.example.com>;
                purpose=EmergencyCallData.VEDS
     Call-Info: <cid:1234567892@atlanta.example.com>;
                purpose=EmergencyCallData.Control
     Accept: application/sdp, application/pidf+xml,
             application/EmergencyCallData.Control+xml
     Recv-Info: EmergencyCallData.eCall
     Allow: INVITE, ACK, PRACK, INFO, OPTIONS, CANCEL, REFER, BYE,
            SUBSCRIBE, NOTIFY, UPDATE
     CSeq: 31862 INVITE
     Content-Type: multipart/mixed; boundary=boundary1
     Content-Length: ...

     --boundary1
     Content-Type: application/sdp

     ...Session Description Protocol (SDP) goes here

     --boundary1
      Content-Type: application/pidf+xml
      Content-ID: <target123@atlanta.example.com>
      Content-Disposition: by-reference;handling=optional

      <?xml version="1.0" encoding="UTF-8"?>
      <presence
         xmlns="urn:ietf:params:xml:ns:pidf"
         xmlns:dm="urn:ietf:params:xml:ns:pidf:data-model"
         xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10"
         xmlns:dyn="urn:ietf:params:xml:ns:pidf:geopriv10:dynamic"
         xmlns:gml="http://www.opengis.net/gml"
         xmlns:gs="http://www.opengis.net/pidflo/1.0"
         entity="sip:+13145551111@example.com">
         <dm:device id="123">
             <gp:geopriv>
                 <gp:location-info>
                     <gml:Point srsName="urn:ogc:def:crs:EPSG::4326">
                        <gml:pos>-34.407 150.883</gml:pos>
                     </gml:Point>
                      <dyn:Dynamic>



Gellens, et al.              Standards Track                   [Page 24]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


                         <dyn:heading>278</dyn:heading>
                         <dyn:direction></dyn:direction>
                      </dyn:Dynamic>
                 </gp:location-info>
                 <gp:usage-rules/>
                 <method>gps</method>
             </gp:geopriv>
             <timestamp>2012-04-5T10:18:29Z</timestamp>
             <dm:deviceID>1M8GDM9A_KP042788</dm:deviceID>
         </dm:device>
  </presence>

      --boundary1
      Content-Type: application/EmergencyCallData.VEDS+xml
      Content-ID: <1234567890@atlanta.example.com>
      Content-Disposition: by-reference;handling=optional

      <?xml version="1.0" encoding="UTF-8"?>
      <AutomatedCrashNotification xmlns="http://www.veds.org/acn/1.0"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

      <Crash>
          <CrashVehicle>
              <ItemMakeName xmlns="http://niem.gov/niem/niem-core/2.0">
                  Saab
              </ItemMakeName>
              <ItemModelName xmlns="http://niem.gov/niem/niem-core/2.0">
                  9-5
              </ItemModelName>
              <ItemModelYearDate
                  xmlns="http://niem.gov/niem/niem-core/2.0">
                  2015
              </ItemModelYearDate>
              <Airbag>
                  <AirbagCategoryCode>FRONT</AirbagCategoryCode>
                  <AirbagDeployedIndicator>true
                  </AirbagDeployedIndicator>
              </Airbag>
              <ConvertibleIndicator>false</ConvertibleIndicator>
              <PowerSourceCategoryCode>MAIN</PowerSourceCategoryCode>
              <VehicleBodyCategoryCode
                  xmlns="http://niem.gov/niem/domains/jxdm/4.1">
                  101
              </VehicleBodyCategoryCode>
              <VehicleCrashPulse>
                  <CrashPulseChangeInVelocityMeasure>
                      <MeasurePointValue
                          xmlns="http://niem.gov/niem/niem-core/2.0">



Gellens, et al.              Standards Track                   [Page 25]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


                          100
                      </MeasurePointValue>
                      <MeasureUnitText
                          xmlns="http://niem.gov/niem/niem-core/2.0">
                          MPH</MeasureUnitText>
                   </CrashPulseChangeInVelocityMeasure>
                          <CrashPulsePrincipalDirectionOfForceValue>12
                          </CrashPulsePrincipalDirectionOfForceValue>
                  <CrashPulseRolloverQuarterTurnsValue>1
                  </CrashPulseRolloverQuarterTurnsValue>
              </VehicleCrashPulse>
              <VehicleRollbarDeployedIndicator>false
              </VehicleRollbarDeployedIndicator>
              <VehicleSeat>
                  <VehicleSeatLocationCategoryCode>1
                  </VehicleSeatLocationCategoryCode>
                  <VehicleSeatOccupiedIndicator>true
                  </VehicleSeatOccupiedIndicator>
                  <VehicleSeatbeltFastenedIndicator>true
                  </VehicleSeatbeltFastenedIndicator>
                  <VehicleSeatbeltMonitoredIndicator>true
                  </VehicleSeatbeltMonitoredIndicator>
              </VehicleSeat>
              <VehicleUnladenWeightMeasure
                  xmlns="http://niem.gov/niem/niem-core/2.0">
                  <MeasurePointValue
                      xmlns="http://niem.gov/niem/niem-core/2.0">
                      600
                      </MeasurePointValue>
                  <MeasureUnitText
                      xmlns="http://niem.gov/niem/niem-core/2.0">
                      kilogram
                  </MeasureUnitText>
              </VehicleUnladenWeightMeasure>
          </CrashVehicle>
          <FuelLeakingIndicator>true</FuelLeakingIndicator>
          <MultipleImpactsIndicator>false</MultipleImpactsIndicator>
          <SevereInjuryIndicator>true</SevereInjuryIndicator>
          <VehicleFinalRestOrientationCategoryCode>Driver
          </VehicleFinalRestOrientationCategoryCode>
          <VehicleFireIndicator>false</VehicleFireIndicator>
      </Crash>
  </AutomatedCrashNotification>

      --boundary1
      Content-Type: application/EmergencyCallData.Control+xml
      Content-ID: <1234567892@atlanta.example.com>
      Content-Disposition: by-reference;handling=optional



Gellens, et al.              Standards Track                   [Page 26]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


      <?xml version="1.0" encoding="UTF-8"?>
      <EmergencyCallData.Control
           xmlns="urn:ietf:params:xml:ns:EmergencyCallData:control"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

       <capabilities>
           <request action="send-data" supported-datatypes="VEDS"/>
           <request action="lamp"
                    supported-values="head;interior;fog-front;fog-rear;
                    brake;position-front;position-rear;turn-left;
                    turn-right;hazard"/>
           <request action="msg-static" int-id="3"/>
           <request action="msg-dynamic"/>
           <request action="honk"/>
           <request action="enable-camera"
                    supported-values="backup;interior"/>
           <request action="door-lock"/>
       </capabilities>

      </EmergencyCallData.Control>

      --boundary1--

       Figure 11: SIP INVITE for a Vehicle-Initiated Emergency Call

12.  Security Considerations

   Since this document relies on [RFC8147] and [RFC7852], the security
   considerations described in those specifications apply here.  The
   security considerations of [RFC5069] apply as well.  Implementors are
   cautioned to read and understand the discussion in those documents.

   In emergency service systems where location data is supplied or
   determined with the assistance of an end host, it is possible that
   the location is incorrect, either intentionally (e.g., in a denial-
   of-service attack against the emergency services infrastructure) or
   due to a malfunctioning device.  The reader is referred to [RFC7378]
   for a discussion of some of these vulnerabilities.

   In addition to the security considerations discussion specific to the
   metadata/control object in [RFC8147], note that vehicles MAY decline
   to carry out any requested action (e.g., if the vehicle requires but
   is unable to verify the certificate used to sign the request).  The
   vehicle MAY use any value in the reason registry to indicate why it
   did not take an action (e.g., the generic "unable" or the more
   specific "security-failure").  Because some actions carry more
   potential risk than others (e.g., unlocking a door versus flashing
   lights), vehicle policy MAY decline to carry out some requests in



Gellens, et al.              Standards Track                   [Page 27]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   some circumstances (e.g., decline a request to unlock doors, send an
   updated VEDS, or enable a camera received in a vehicle-terminated
   call while carrying out such requests received in a vehicle-initiated
   emergency call).

13.  Privacy Considerations

   Since this document builds on [RFC8147], which itself builds on
   [RFC7852], the data structures specified there, and the corresponding
   privacy considerations discussed there, apply here as well.  The VEDS
   data structure contains optional elements that can carry identifying
   and personal information, both about the vehicle and about the owner,
   as well as location information, so it needs to be protected against
   unauthorized disclosure, as discussed in [RFC7852].  Local
   regulations may impose additional privacy protection requirements.

   The additional functionality enabled by this document, such as access
   to vehicle camera streams, carries a burden of protection, so
   implementations need to be careful that access is only provided
   within the context of an emergency call or to an emergency services
   provider (e.g., by verifying that the request for camera access is
   signed by a certificate issued by an emergency services registrar).

14.  IANA Considerations

   This document registers the application/EmergencyCallData.VEDS+xml
   MIME media type and adds "VEDS" to the "Emergency Call Data Types"
   registry.  This document adds to and creates sub-registries in the
   "Emergency Call Metadata/Control Data" registry created in [RFC8147].
   In addition, this document registers a new INFO package.

14.1.  MIME Media Type Registration for application/
       EmergencyCall.VEDS+xml

   IANA has registered a new MIME media type according to the procedures
   of [RFC6838] and guidelines in [RFC7303].

      MIME media type name:  application

      MIME subtype name:  EmergencyCallData.VEDS+xml

      Mandatory parameters:  none

      Optional parameters:  charset
         Indicates the character encoding of enclosed XML.






Gellens, et al.              Standards Track                   [Page 28]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


      Encoding considerations:
         Uses XML, which can employ 8-bit characters, depending on the
         character encoding used.  See Section 3.2 of RFC 7303
         [RFC7303].

      Security considerations:
            This media type is designed to carry vehicle crash data
            during an emergency call.

            This data can contain personal information including vehicle
            VIN, location, direction, etc.  Appropriate precautions need
            to be taken to limit unauthorized access, inappropriate
            disclosure to third parties, and eavesdropping of this
            information.  Please refer to Sections 9 and 10 of [RFC7852]
            for more information.

            When this media type is contained in a signed or encrypted
            body part, the enclosing multipart (e.g., multipart/signed
            or multipart/encrypted) has the same Content-ID as the data
            part.  This allows an entity to identify and access the data
            blocks it is interested in without having to dive deeply
            into the message structure or decrypt parts it is not
            interested in.  (The "purpose" parameter in a Call-Info
            header field identifies the data, and the CID URL points to
            the data block in the body, which has a matching Content-ID
            body part header field.)

      Interoperability considerations:  None

      Published specification:  [VEDS]

      Applications which use this media type:  Emergency Services

      Additional information:  None

      Magic Number:  None

      File Extension:  .xml

      Macintosh file type code:  TEXT

      Persons and email addresses for further information:
         Randall Gellens, rg+ietf@randy.pensive.org;
         Hannes Tschofenig, Hannes.Tschofenig@gmx.net

      Intended usage:  LIMITED USE





Gellens, et al.              Standards Track                   [Page 29]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


      Author:
         This specification is a work item of the IETF ECRIT working
         group, with mailing list address <ecrit@ietf.org>.

      Change controller:  The IESG <ietf@ietf.org>

14.2.  Registration of the "VEDS" Entry in the Emergency Call Data Types
       Registry

   IANA has added "VEDS" to the "Emergency Call Data Types" registry,
   with a reference to this document; the "Data About" value is "The
   Call".  The "Emergency Call Data Types" registry was established by
   [RFC7852].

14.3.  New Action Values

   This document adds new values for the "action" attribute of the
   <request> element in the "Emergency Call Action" registry created by
   [RFC8147].

                +---------------+-------------------------+
                |      Name     |       Description       |
                +---------------+-------------------------+
                |   msg-static  | Section 9.1 of RFC 8148 |
                |               |                         |
                |  msg-dynamic  | Section 9.1 of RFC 8148 |
                |               |                         |
                |      honk     | Section 9.1 of RFC 8148 |
                |               |                         |
                |      lamp     | Section 9.1 of RFC 8148 |
                |               |                         |
                | enable-camera | Section 9.1 of RFC 8148 |
                |               |                         |
                |   door-lock   | Section 9.1 of RFC 8148 |
                +---------------+-------------------------+

            Table 1: Emergency Call Action Registry New Values














Gellens, et al.              Standards Track                   [Page 30]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


14.4.  Emergency Call Static Messages Registry

   This document creates a new sub-registry called "Emergency Call
   Static Messages" in the "Emergency Call Metadata/Control Data"
   registry established by [RFC8147].  Because compliant vehicles are
   expected to support all static messages translated into all languages
   supported by the vehicle, it is important to limit the number of such
   messages.  As defined in [RFC5226], this registry operates under
   "Specification Required", which requires a stable, public document
   and implies expert review of the publication.  The expert should
   determine that the document has been published by an appropriate
   emergency services organization (e.g., NENA, EENA, or APCO) or by the
   IETF with input from an emergency services organization, and that the
   proposed message is sufficiently distinguishable from other messages.

   The contents of this registry are:

   ID:  An integer identifier to be used in the "int-id" attribute of a
      metadata/control <request> element.

   Message:  The text of the message.  Messages are listed in the
      registry in English; vehicles are expected to implement
      translations into languages supported by the vehicle.

   When new messages are added to the registry, the message text is
   determined by the registrant; IANA assigns the IDs.  Each message is
   assigned a consecutive integer value as its ID.  This allows an IVS
   to indicate by a single integer value that it supports all messages
   with that value or lower.  The value 0 is reserved; usable messages
   start with 1.

   The initial set of values is listed in Table 2.

   +----+--------------------------------------------------------------+
   | ID | Message                                                      |
   +----+--------------------------------------------------------------+
   | 0  | Reserved                                                     |
   |    |                                                              |
   | 1  | Emergency services has received your information and         |
   |    | location but cannot speak with you right now.  We will get   |
   |    | help to you as soon as possible.                             |
   +----+--------------------------------------------------------------+

      Table 2: Emergency Call Static Messages Registry Initial Values







Gellens, et al.              Standards Track                   [Page 31]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


14.5.  Emergency Call Vehicle Lamp IDs Registry

   This document creates a new sub-registry called "Emergency Call
   Vehicle Lamp IDs" in the "Emergency Call Metadata/Control Data"
   registry established by [RFC8147].  This new sub-registry uniquely
   identifies the names of automotive lamps (lights).  As defined in
   [RFC5226], this registry operates under "Expert Review" rules.  The
   expert should determine that the proposed lamp name is clearly
   understandable and is sufficiently distinguishable from other lamp
   names.

   The contents of this registry are:

   Name:  The identifier to be used in the "element-id" attribute of a
      metadata/control <request> element.

   Description:  A description of the lamp (light).

   The initial set of values is listed in Table 3.

     +----------------+---------------------------------------------+
     | Name           | Description                                 |
     +----------------+---------------------------------------------+
     | head           | The main lamps used to light the road ahead |
     |                |                                             |
     | interior       | Interior lamp, often at the top center      |
     |                |                                             |
     | fog-front      | Front fog lamps                             |
     |                |                                             |
     | fog-rear       | Rear fog lamps                              |
     |                |                                             |
     | brake          | Brake indicator lamps                       |
     |                |                                             |
     | brake-center   | Center high-mounted stop lamp               |
     |                |                                             |
     | position-front | Front position/parking/standing lamps       |
     |                |                                             |
     | position-rear  | Rear position/parking/standing lamps        |
     |                |                                             |
     | turn-left      | Left turn/directional lamps                 |
     |                |                                             |
     | turn-right     | Right turn/directional lamps                |
     |                |                                             |
     | hazard         | Hazard/four-way lamps                       |
     +----------------+---------------------------------------------+

          Table 3: Emergency Call Lamp ID Registry Initial Values




Gellens, et al.              Standards Track                   [Page 32]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


14.6.  Emergency Call Vehicle Camera IDs Registry

   This document creates a new sub-registry called "Emergency Call
   Vehicle Camera IDs" in the "Emergency Call Metadata/Control Data"
   registry established by [RFC8147].  This new sub-registry uniquely
   identifies automotive cameras.  As defined in [RFC5226], this
   registry operates under "Expert Review" rules.  The expert should
   determine that the proposed camera name is clearly understandable and
   is sufficiently distinguishable from other camera names.

   The contents of this registry are:

   Name:  The identifier to be used in the "element-id" attribute of a
      control <request> element.

   Description:  A description of the camera.

   The initial set of values is listed in Table 4.

































Gellens, et al.              Standards Track                   [Page 33]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   +-------------+-----------------------------------------------------+
   | Name        | Description                                         |
   +-------------+-----------------------------------------------------+
   | backup      | Shows what is behind the vehicle, e.g., often used  |
   |             | for driver display when the vehicle is in reverse.  |
   |             | Also known as rearview, reverse, rear visibility,   |
   |             | etc.                                                |
   |             |                                                     |
   | left-rear   | Shows view to the left and behind (e.g., left-side  |
   |             | rearview mirror or blind spot view)                 |
   |             |                                                     |
   | right-rear  | Shows view to the right and behind (e.g., right-    |
   |             | side rearview mirror or blind spot view)            |
   |             |                                                     |
   | forward     | Shows what is in front of the vehicle               |
   |             |                                                     |
   | rear-wide   | Shows what is behind the vehicle (e.g., used by     |
   |             | rear-collision detection systems), separate from    |
   |             | backup view                                         |
   |             |                                                     |
   | lane        | Used by systems to identify road lane and/or        |
   |             | monitor the vehicle's position within lane          |
   |             |                                                     |
   | interior    | Shows the interior (e.g., driver)                   |
   |             |                                                     |
   | night-front | Night-vision view of what is in front of the        |
   |             | vehicle                                             |
   |             |                                                     |
   | night-rear  | Night-vision view of what is behind the vehicle     |
   |             |                                                     |
   | night-left  | Night-vision view of what is to the left of the     |
   |             | vehicle                                             |
   |             |                                                     |
   | night-right | Night-vision view of what is to the right of the    |
   |             | vehicle                                             |
   +-------------+-----------------------------------------------------+

    Table 4: Emergency Call Vehicle Camera IDs Registry Initial Values













Gellens, et al.              Standards Track                   [Page 34]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


14.7.  The EmergencyCallData.VEDS INFO Package

   This document registers the EmergencyCallData.VEDS INFO package in
   the "Info Packages Registry".

   Both endpoints (the IVS and the PSAP equipment) include
   "EmergencyCallData.VEDS" in a Recv-Info header field per [RFC6086] to
   indicate the ability to receive SIP INFO messages carrying data as
   described here.

   Support for the EmergencyCallData.VEDS INFO package indicates the
   ability to receive NG-ACN-related body parts as specified in this
   document.

   A SIP INFO request message carrying data related to an emergency call
   as described in this document has an Info-Package header field set to
   "EmergencyCallData.VEDS" per [RFC6086].

   The requirements of Section 10 of [RFC6086] are addressed in the
   following sections.

14.7.1.  Overall Description

   This section describes what type of information is carried in INFO
   requests associated with the INFO package and for what types of
   applications and functionalities User Agents (UAs) can use the INFO
   package.

   SIP INFO requests associated with the EmergencyCallData.VEDS INFO
   package carry data associated with emergency calls as defined in this
   document.  The application is vehicle-initiated emergency calls
   established using SIP.  The functionality is to carry vehicle data
   and metadata/control information between vehicles and PSAPs.

14.7.2.  Applicability

   This section describes why the INFO package mechanism, rather than
   some other mechanism, has been chosen for the specific use case.

   The use of the SIP INFO method is based on an analysis of the
   requirements against the intent and effects of the INFO method versus
   other approaches (which included the SIP MESSAGE method, SIP OPTIONS
   method, SIP re-INVITE method, media-plane transport, and non-SIP
   protocols).  In particular, the transport of emergency call data
   blocks occurs within a SIP emergency dialog, per Section 7, and is
   normally carried in the initial INVITE request and its response; the
   use of the INFO method only occurs when emergency-call-related data
   needs to be sent mid call.  While the SIP MESSAGE method could be



Gellens, et al.              Standards Track                   [Page 35]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   used, it is not tied to a SIP dialog as is the INFO method and thus
   might not be associated with the dialog.  Both the SIP OPTIONS or
   re-INVITE methods could also be used, but they are seen as less clean
   than the INFO method.  The SIP SUBSCRIBE/NOTIFY method could be
   coerced into service, but the semantics are not a good fit, e.g., the
   subscribe/notify mechanism provides one-way communication consisting
   of (often multiple) notifications from notifier to subscriber
   indicating that certain events in the notifier have occurred, whereas
   what's needed here is two-way communication of data related to the
   emergency dialog.  Use of media-plane mechanisms was discounted
   because the number of messages needing to be exchanged in a dialog is
   normally zero or very few, and the size of the data is likewise very
   small.  The overhead caused by user-plane setup (e.g., to use the
   Message Session Relay Protocol (MSRP) as transport) would be
   disproportionately large.

   Based on the analyses, the SIP INFO method was chosen to provide for
   mid-call data transport.

14.7.3.  INFO Package Name

   The INFO package name is EmergencyCallData.VEDS.

14.7.4.  INFO Package Parameters

   None

14.7.5.  SIP Option-Tags

   None

14.7.6.  INFO Request Body Parts

   The body of an EmergencyCallData.VEDS INFO package is a multipart
   body containing zero or one application/EmergencyCallData.VEDS+xml
   parts (containing a VEDS data block), zero or more application/
   EmergencyCallData.Control+xml (containing a metadata/control object)
   parts, and zero or one application/EmergencyCallData.eCall.MSD parts
   (containing an MSD).  At least one VEDS, MSD, or metadata/control
   body part is expected; the behavior upon receiving a SIP INFO request
   with none is undefined.

   The body parts are sent per [RFC6086]; in addition, to align with how
   these body parts are sent in non-INFO messages, each associated body
   part is referenced by a Call-Info header field at the top level of
   the SIP message.  The body part has a Content-Disposition header
   field set to "By-Reference".




Gellens, et al.              Standards Track                   [Page 36]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


   A VEDS, metadata/control block, or MSD is always enclosed in a
   multipart body part (even if it would otherwise be the only body part
   in the SIP message).  The outermost multipart that contains only body
   parts associated with the INFO package has a Content-Disposition
   value of "Info-Package".

   Service providers in the call path are not expected to add Additional
   Data [RFC7852] to SIP INFO requests (as they would to an initial
   INVITE request).

14.7.7.  INFO Package Usage Restrictions

   Usage is limited to vehicle-initiated emergency calls as defined in
   this document.

14.7.8.  Rate of INFO Requests

   The SIP INFO request is used within an established emergency call
   dialog to send requests, updated data, or an acknowledgment.  Because
   requests are normally sent only on manual action of the PSAP call
   taker (who suspects some aspect of the vehicle state has changed) and
   updated data is sent only when an aspect of previously sent data has
   changed, the rate of SIP INFO requests associated with the
   EmergencyCallData.VEDS INFO package is normally quite low (most
   dialogs are likely to contain zero SIP INFO requests, while others
   can be expected to carry an occasional request).

14.7.9.  INFO Package Security Considerations

   The MIME media type registrations for the data blocks that can be
   carried using this INFO package contains a discussion of the security
   and/or privacy considerations specific to that data block.  See
   Sections 12 and 13 for information on the security and privacy
   considerations of the data carried in vehicle-initiated emergency
   calls.

14.7.10.  Implementation Details

   See Sections 7 and 8 for protocol details.

14.7.11.  Examples

   See Section 11 for protocol examples.








Gellens, et al.              Standards Track                   [Page 37]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


15.  References

15.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              DOI 10.17487/RFC5226, May 2008,
              <http://www.rfc-editor.org/info/rfc5226>.

   [RFC6086]  Holmberg, C., Burger, E., and H. Kaplan, "Session
              Initiation Protocol (SIP) INFO Method and Package
              Framework", RFC 6086, DOI 10.17487/RFC6086, January 2011,
              <http://www.rfc-editor.org/info/rfc6086>.

   [RFC6838]  Freed, N., Klensin, J., and T. Hansen, "Media Type
              Specifications and Registration Procedures", BCP 13,
              RFC 6838, DOI 10.17487/RFC6838, January 2013,
              <http://www.rfc-editor.org/info/rfc6838>.

   [RFC6881]  Rosen, B. and J. Polk, "Best Current Practice for
              Communications Services in Support of Emergency Calling",
              BCP 181, RFC 6881, DOI 10.17487/RFC6881, March 2013,
              <http://www.rfc-editor.org/info/rfc6881>.

   [RFC7303]  Thompson, H. and C. Lilley, "XML Media Types", RFC 7303,
              DOI 10.17487/RFC7303, July 2014,
              <http://www.rfc-editor.org/info/rfc7303>.

   [RFC7852]  Gellens, R., Rosen, B., Tschofenig, H., Marshall, R., and
              J. Winterbottom, "Additional Data Related to an Emergency
              Call", RFC 7852, DOI 10.17487/RFC7852, July 2016,
              <http://www.rfc-editor.org/info/rfc7852>.

   [RFC8147]  Gellens, R. and H. Tschofenig, "Next-Generation Pan-
              European eCall", RFC 8147, DOI 10.17487/RFC8147, May 2017,
              <http://www.rfc-editor.org/info/rfc8147>.

   [VEDS]     APCO International, "Vehicular Emergency Data Set (VEDS)",
              Version 3.0, Prepared by the Advanced Automatic Crash
              Notification (AACN) Joint APCO/NENA Data Standardization
              Working Group, February 2012, <https://www.apcointl.org/
              resources/telematics/aacn-and-veds.html>.




Gellens, et al.              Standards Track                   [Page 38]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


15.2.  Informative references

   [Bluetooth]
              Bluetooth Special Interest Group (SIG), "Bluetooth
              Specifications", <https://www.bluetooth.com/
              specifications>.

   [RFC5012]  Schulzrinne, H. and R. Marshall, Ed., "Requirements for
              Emergency Context Resolution with Internet Technologies",
              RFC 5012, DOI 10.17487/RFC5012, January 2008,
              <http://www.rfc-editor.org/info/rfc5012>.

   [RFC5069]  Taylor, T., Ed., Tschofenig, H., Schulzrinne, H., and M.
              Shanmugam, "Security Threats and Requirements for
              Emergency Call Marking and Mapping", RFC 5069,
              DOI 10.17487/RFC5069, January 2008,
              <http://www.rfc-editor.org/info/rfc5069>.

   [RFC6443]  Rosen, B., Schulzrinne, H., Polk, J., and A. Newton,
              "Framework for Emergency Calling Using Internet
              Multimedia", RFC 6443, DOI 10.17487/RFC6443, December
              2011, <http://www.rfc-editor.org/info/rfc6443>.

   [RFC7378]  Tschofenig, H., Schulzrinne, H., and B. Aboba, Ed.,
              "Trustworthy Location", RFC 7378, DOI 10.17487/RFC7378,
              December 2014, <http://www.rfc-editor.org/info/rfc7378>.

   [triage-2008]
              National Center for Injury Prevention and Control,
              "Recommendations from the Expert Panel: Advanced Automatic
              Collision Notification and Triage of the Injured Patient",
              Centers for Disease Control and Prevention, 2008,
              <https://stacks.cdc.gov/view/cdc/5304/>.

   [triage-2011]
              National Center for Injury Prevention and Control,
              "Guidelines for Field Triage of Injured Patients:
              Recommendations of the National Expert Panel on Field
              Triage", Centers for Disease Control and Prevention,
              January 2012, <https://www.cdc.gov/mmwr/preview/mmwrhtml/
              rr6101a1.htm>.










Gellens, et al.              Standards Track                   [Page 39]

RFC 8148            Vehicle-Initiated Emergency Calls           May 2017


Acknowledgments

   We would like to thank Lena Chaponniere, Alissa Cooper, Stephen Edge,
   Christer Holmberg, Allison Mankin, and Dan Romascanu for their review
   and suggestions; Robert Sparks and Paul Kyzivat for their help with
   the SIP mechanisms; Michael Montag, Arnoud van Wijk, Ban Al-Bakri,
   Wes George, Gunnar Hellstrom, and Rex Buddenberg for their feedback;
   and Ulrich Dietz for his help with preliminary draft versions of the
   original document that later evolved into this document.

Authors' Addresses

   Randall Gellens
   Core Technology Consulting

   Email: rg+ietf@coretechnologyconsulting.com
   URI:   http://www.coretechnologyconsulting.com


   Brian Rosen
   NeuStar, Inc.
   470 Conrad Dr
   Mars, PA  16046
   United States of America

   Email: br@brianrosen.net


   Hannes Tschofenig
   Individual

   Email: Hannes.Tschofenig@gmx.net
   URI:   http://www.tschofenig.priv.at


















Gellens, et al.              Standards Track                   [Page 40]