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Network Working Group                                        A. Petrescu
Internet-Draft                                              C. Janneteau
Intended status: Informational                                    M. Boc
Expires: April 6, 2014                                               CEA
                                                              W. Klaudel
                                                         October 3, 2013

Scenarios and Requirements for IP in Intelligent Transportation Systems


   This draft describes scenarios of vehicular communications that are
   considered pertinent to Intelligent Transportation Systems.  In these
   scenarios, the necessity of using IP networking technologies and
   protocols is exposed.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on April 6, 2014.

Copyright Notice

   Copyright (c) 2013 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
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Scenarios  . . . . . . . . . . . . . . . . . . . . . . . . . .  4
     3.1.  Intra-Vehicular (V)  . . . . . . . . . . . . . . . . . . .  5
     3.2.  Vehicle-to-Infrastructure (V2I)  . . . . . . . . . . . . .  7
     3.3.  Vehicle-to-Vehicle (V2V) and V2RSU . . . . . . . . . . . .  7
     3.4.  Vehicle-to-Vehicle-to-Infrastructure (V2V2I) . . . . . . .  9
     3.5.  Infrastructure Support . . . . . . . . . . . . . . . . . .  9
   4.  Requirements . . . . . . . . . . . . . . . . . . . . . . . . .  9
   5.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 10
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 10
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 11
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 11
   Appendix A.  ChangeLog . . . . . . . . . . . . . . . . . . . . . . 11
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12

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1.  Introduction

   The field of vehicular communications is encompassing a large number
   of wired and wireless technologies.  In particular, the breakthrough
   advancements in wide-area cellular telecommunications, the advent of
   inexpensive hardware, impressively high bandwidth and low-cost data
   subscription plans make possible new paradigms which put the vehicle
   at the center of a communications ecosystem.  It can be observed that
   whereas only in the recent past linking vehicles in a robust manner
   to a fixed infrastructure represented endeavors available only to top
   categories, more and more middle category vehicles are announced to
   take advantage of data connectivity.

   Communication protocols used in the fixed and mobile (terminal)
   Internet can be applied in the scenarios employing vehicles which
   communicate.  A number of particular aspects make vehicular
   communications different, not least being the that mobility is the
   norm, rather than the exception.  At the same time, several protocols
   developped at IETF are good candidates to form basis of further
   development of IP protocols for vehicular communications.

   The use of Internet protocols in the vehicular scenarios may prove
   advantageous from several standpoints:

   o  immediate availability of a large number of applications with an
      established customer base.

   o  scalability: large numbers of inter-communicating vehicles can be
      accommodated across large distances.

   o  accessing heterogeneous, mixed and multiple-standard link layer

   The context of vehicular communications considers the use of several
   classes of Internet protocols for vehicular applications.  One
   particular family of protocols is Mobile IP.  Its salient features
   characterize well several mobility aspects such as reachability at
   permanent addresses, seamless handovers and group mobility
   management.  Earlier documents at IETF idenfitied a number of
   scenarios and potential requirements for further work towards
   improving the Mobile IP protocols for a better adaptation in
   vehicular environments (see for example the draft titled "Automotive
   Industry Requirements for NEMO Route Optimization" edited in 2009

   A Vehicle-to-Infrastructure scenario (V2I) is a typical setting in
   which a vehicle uses a long-range wireless interface (cellular,
   sattelite) to connect to a fixed infrastructure.  As a separate

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   matter, scenarios of Vehicle-to-Vehicle (V2V) communications consider
   direct communications between vehicles, without, or with minimal,
   assistance from the infrastructure.  In areas where wireless coverage
   is absent, Vehicle-to-Vehicle-to-Infrastructure communications are
   scenarios where covered vehicles offer access to non covered
   vehicles, in a multi-hop manner.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in RFC 2119 [RFC2119].

3.  Scenarios

   Several scenarios of vehicular communications are described.  We
   choose a set of illustrative scenarios, described next, and then
   followed by a list of high-level topologies which may be considered
   in terms of IP communications (V2V, V2I, etc.)

   Scenario 1: A rented car (for instance a autolib as in Paris) is
   (will be) equipped with the car manufacturer network (sensors, CAN
   bus monitoring, infotainement), the car rental owner network
   (accidents detection, geolocation, etc.), the insurer network for
   behavior detection (speed, location, distance, etc.), and other
   stakeholders network such as highway company, municipality public
   service company (detection of free parking for instance), etc.  Those
   sub-networks may be interconnected together by one (mobile) router
   that ensures stable IP connectivity.

   Scenario 2: Because of the wide variety of available wireless
   technologies, the vehicle should dispose of more than one wireless
   interface towards the infrastructure.  In city center, Wi-Fi hotspots
   may provide Internet access at crossing roads stops.  In the suburbs,
   Internet Access may only be available with LTE or 3G.

   Scenario 3: An ambulance may need to stream video to the main
   hospital requesting minimum bandwidth during the whole operation.
   The mobile router should consider this requirement and prevent other
   less important traffic from the vehicle to have a negative impact on
   the stream.

   Scenario 4: 802.11p may support the broadcast of alerts to vehicles.
   If the mobile router hosts a 802.11p interface, such alerts should be
   handled accordingly and routed to the right subnetworks.

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   Scenario 5: The vehicle may have a large amount of data to transfer
   to another vehicle but have only an Edge connection with the
   infrastructure.  The transmission of the data may be delayed until a
   WiFi, 3G, or LTE connection becomes available.

   Scenario 6: MANET routing between vehicles may be inefficient if the
   two communicating vehicles are not in vicinity.  By using
   geographical information, the mobile router may know how to route
   data towards the destination efficiently.

   Scenario 7: The insurer (generic term), the car manufacturer, and
   other stakeholder do not want to share their (private) data.  The
   insurer do not want to let data coming from a network where the
   driver is active to have an influence on the reported behavioral

3.1.  Intra-Vehicular (V)

   Within one particular vehicle, an entire network may and will be
   deployed.  This network is constituted of routers, hosts and other
   entities configured each with one or several IP addresses.  Devices
   within vehicles are reachable to other vehicles and to Internet at

   One illustration of an intra-vehicular network is depicted in the
   next figure:

                     |  |  ... |  n interfaces to the outside of vehicle
                  | Mobile Router |
                      /   |   \   m IP subnets within the vehicle
                     /    |    \
                     | D.Router|
                    /     |     \---CAN--
                   /      |
               sensors     \-----entertainment subnet

    Figure 1: Topology for Vehicle-to-Infrastructure V2I Communications

   This figure tries to illustrate the complexity of a intra-vehicular
   network.  Even though the first deployments of intra-vehicular

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   networks were being constructed using a single IP subnet, the most
   recent advancements propose the use of multiple subnets within one

   In this example deployment, the moving vehicle holds on-board a
   Mobile Router.  The MR is in charge of communicating to the outside
   world.  It is equipped with one or several wireless interfaces
   towards the outside world (the world 'wireless' should be understood
   largely as 'without wires'; near-field contact-less communications
   are proposed for vehicular communications as well).

   Within a vehicle, a dedicated router (D.Router) is in charge of
   subnets whose purpose is more application specific.  The applications
   are typical vehicular, like the applications communicating on CAN
   (Car Area Network).  This router may also be forwarding packets of
   less importance (less constrained in terms of real time) which are
   related to entertainment (e.g. video stream to a screen built into a
   front seat).

   Within one vehicle, there may thus be deployed several IP subnets,
   with traffic separated, dedicated to particular applications.  The
   network within a vehicle may be formed by Routers, Switches and
   Hosts.  It is also very probable that mobile devices carried by
   passengers connect to the vehicle's network, in a dynamic manner
   (users would expect and IP session ongoing on their personal terminal
   to continue working when getting into and outside of a vehicle).

   The IP addressing scheme for deployment in a vehicle is not
   straightforward.  The addresses should follow the pattern of use of
   applications: constrained applications may need to be separated from
   the entertainment applications right at the addressing level.  For
   example, it may be needed to assign ULAs to some devices dedicated to
   some applications, Global addresses to other devices and link-local
   addresses on links where communication is local.

   The topology of the intra-vehicular network may be interpreted as a
   multi-stage deployment; the multiplicity of stages is serving to
   protect against external attacks from the Internet to the inherent
   mechanisms of the vehicle dedicated CAN.

   The Mobile Router deployed in a vehicle is in charge of
   communications to the outside world.  One example application on the
   MR is the following: in case that two versions of the IP protocol
   need to be deployed and interoperable, then the MR may run a proxy
   HTTP function to allow IPv6 clients on-board to query IPv4 servers in
   the fixed Internet.

   Some scenarios considered for vehicle communications need to take

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   into account that the vehicle is powered by very complex schemes
   which include power-saving mechanisms as well as eventual power
   distribution.  It is important to consider mechanisms to wake-up the
   vehicle by messages coming from the outside network (IP Router Alert,
   or SMS of LTE).

3.2.  Vehicle-to-Infrastructure (V2I)

   This section describes the communication scenario in which one mobile
   vehicle connects to a fixed infrastructure.


                --------             /--------------+
               | Vehicle|---     ---/Fixed          |------>Internet
                --------  wireless  \Infrastructure |
                            link     \--------------+
                        (long range)

    Figure 2: Topology for Vehicle-to-Infrastructure V2I Communications

   In this figure, the wireless link used between the vehicle and the
   fixed infrastructure is of type 'long range' - typically a cellular
   link terminal-infrastructure, alternatively named a Wireless
   Metropolitan Area Network.  A vehicle-to-infrastructure scenario
   considers often that the vehicle uses a cellular interface attached
   to an on-board router.

   A different V2I scenario involves the use of short-range wireless
   links between the vehicle and the infrastructure.  For example, it is
   possible to use interfaces of type IEEE 802.11b, or 802.11p to
   connect to a fixed infrastructure, which is itself connected to the
   Internet.  The first IP hop between the vehicle and the
   infrastructure is using a short-range communication link.

3.3.  Vehicle-to-Vehicle (V2V) and V2RSU


                           --------             --------
                          | Vehicle|--       --| Vehicle|
                           --------  wireless   --------

       Figure 3: Topology for Vehicle-to-Vehicle V2V Communications

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   In this figure, the wireless link is of type short range.  One
   vehicle uses a interface of kind IEEE 802.11b, for example, and
   communicates to another vehicle using same kind of interface.
   Contrary to cellular links, the short-range wireless links are active
   in smaller areas (in terms of square meters of area).  Typical
   examples of short-range wireless links are IEEE 802.11b, or IEEE
   802.11p.  The link IEEE 802.11p may benefit from longer range
   transmissions: spectrum regulators in certain regions allow for power
   levels as high as 33 dBM (Europe) or 44 dBm (US) which corresponds to
   distances in the order of magnitude of kilometers (as compared to
   tens of meters for 802.11b).

   There are several possibilities of using short-range wireless between
   vehicles.  In one scenario, the link uses the ad-hoc mode of
   operation between the egress interfaces of on-board vehicles.  This
   works without the use of a fixed infrastructure.  In another
   scenario, the link may use the 'managed' mode of operation between
   the egress interfaces of on-board vehicles; an Access Point is
   necessary for this to operate; the Access Point may be elected among
   one of the vehicles, or it may be deployed in a fixed manner along
   the road.  When the link is 802.11p, the operation may be similar to
   the ad-hoc mode of 802.11b, and simplified even further: the
   operation outside the context of a BSS ('OCB') involves total absence
   of beacons and association or authentication messages.

   One potential application of the V2V topology is the communication
   between a Vehicle and a Road-Side Unit; this RSU may be disconnected
   from the Internet.

                           +--------+           +-------+
                           | Mobile |           | Fixed |
                           | Vehicle|--       --|  RSU  |
                           +--------+ wireless  +-------+

                 Figure 4: V2RSU Topology (similar to V2V)

   In this topology, the Vehicle communicates directly with the RSU
   which is fixed.  The RSU may 'broadcast' IP packets (disseminate,
   without request, to everybody in range) information which is
   pertinent to the particular location of that RSU.

   A set of possible scenarios may be constructed between the V2V and
   the V2I scenarios with respect to fixed infrastructure.  At one
   extreme, the presence of fixed infrastructure is completely

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   disallowed for V2V communications, and the short-range communications
   are completely disallowed between vehicles which perform V2I. Along
   the set of scenarios, one scenario is possible where fixed
   infrastructure is deployed with the goal to support V2V
   communications but without offering Internet access.  Also along this
   set of values the V2RSU is a topology where the vehicle communicates
   direclty with a fixed RSU, in the same manner it would communicate in
   a V2V topology.  At the other extreme of this set of values, V2I
   communications may be realized by building a complete infrastructure
   with moving vehicles.

3.4.  Vehicle-to-Vehicle-to-Infrastructure (V2V2I)


      --------             --------       /-------------+
     | Vehicle|--       --| Vehicle|-- --/Fixed         |----->Internet
      --------  wireless   --------  w   \Infrastructure|
                  link              link  \-------------+
               (short range)     (long range)

     Figure 5: Topology for Vehicle-to-Vehicle-to-Infrastructure V2V2I

   In Vehicle-to-Vehicle-to-Infrastructure (V2V2I) communications a mix
   is realized between V2V communications and V2I communications.  For
   example, a subnet is established between two vehicles in a V2V manner
   (e.g. using the ad-hoc mode between egress interfaces of on-board
   routers of vehicles), and one of the vehicles is simultaneously
   connected to the fixed infrastructure (and to the Internet) using a
   V2I cellular link.

3.5.  Infrastructure Support

4.  Requirements

   o  R0.  IP addressing within each vehicle.

   o  R1.  IP addressing on the interface between vehicles.

   o  R2.  Sub-networks support: Mobile router support several sub-
      networks hosting stakeholder networks,

   o  R3.  Support of multiple interfaces: The vehicle (not restricted
      to the MR physically) should support several interfaces towards
      the infrastructure.

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   o  R4.  Quality of Service: One stakeholder may request for a minimum
      bandwidth for its applications.  QoS should ensure those minimums
      are taken into accounts.

   o  R5.  Broadcasted Alerts support: Along the highway, the MR may
      receive alerts about accident through 802.11p.

   o  R6.  Store, Carry and Forward: Improve communication efficiency by
      delaying transfer of information.

   o  R7.  Geographic information support: Efficient inter-vehicular
      routing may take advantage of geographic information (not
      restricted to geonetworking).

   o  R8.  Security: MR must prevent routing of packets between sub
      networks and ensure protection of those data within the vehicle.

   o  R9.  Continuity of ongoing sessions: it is desirable that ongoing
      sessions between one device within the vehicle and one device in
      the Internet is maintained ongoing during vehicle movements, and
      upon handovers between heterogeneous access points.

   o  R10.  Reachability at permanent home addresses: it is desirable
      that each device connected inside a vehicle to be reachable at a
      permanent fixed address, for all other IP devices deployed in the

   o  R11.  It is desirable that devices connected in one vehicle to be
      able to communicate directly to other devices in a vehicle nearby,
      even when the infrastructure is absent, and without using
      artificially long IP paths.

5.  Acknowledgements

   The authors would like to acknowledge colleagues who commented and
   thus helped improving this document.

6.  IANA Considerations

   No particular requirements to IANA.

7.  Security Considerations

   Connecting a vehicle to the Internet poses a number of significant
   problems related to security: new attacks are possible and the

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   vehicle should be protected.

8.  References

8.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

8.2.  Informative References

              Baldessari, R., Ernst, T., Festag, A., and M. Lenardi,
              "Automotive Industry Requirements for NEMO Route
              Optimization", draft-ietf-mext-nemo-ro-automotive-req-02
              (work in progress), January 2009.

Appendix A.  ChangeLog

   The changes are listed in reverse chronological order, most recent
   changes appearing at the top of the list.

   From draft-petrescu-its-scenarios-reqs-02.txt to -03:

   o  Added the use of 802.11p in V2V scenario, and added the V2RSU

   From draft-petrescu-its-scenarios-reqs-01.txt to -02:

   o  No change.

   From draft-petrescu-its-scenarios-reqs-00.txt to -01:

   o  Added requirements from R2 and up.

   o  Better description of V2V, V2I terms.  Introduction of the intra-
      vehicular scenario.

   o  Enumeration of scenarios.

   o  Expanded authorship.

   From -- to draft-petrescu-its-scenarios-reqs-00.txt:

   o  First version of draft issued.

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Authors' Addresses

   Alexandru Petrescu
   Communicating Systems Laboratory, Point Courrier 173
   Palaiseau,   F-91120

   Phone: +33(0)169089223
   Email: alexandru.petrescu@cea.fr

   Christophe Janneteau
   Communicating Systems Laboratory, Point Courrier 173
   Palaiseau,   F-91120

   Phone: +33(0)169089182
   Email: christophe.janneteau@cea.fr

   Michael Mathias Boc
   Communicating Systems Laboratory, Point Courrier 173
   Palaiseau,   F-91120

   Phone: +33 (0) 169083976
   Email: michael.boc@cea.fr

   Witold Klaudel
   1 Av. du Golf
   Guyancourt,   F-78288

   Phone: +33(0)176845680
   Email: witold.klaudel@renault.com

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