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RFC 8148

 
 
 

Next-Generation Vehicle-Initiated Emergency Calls

Part 2 of 2, p. 21 to 40
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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

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   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/

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   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

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   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>

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                         <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">

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                          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

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      <?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

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   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.

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      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

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      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

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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

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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

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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.

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   +-------------+-----------------------------------------------------+
   | 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

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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

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   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".

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   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.

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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>.

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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>.

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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