IPWAVE Working Group                                       J. Jeong, Ed.
Internet-Draft                                   Sungkyunkwan University
Intended status: Informational                             July 2, 16, 2018
Expires: January 3, 17, 2019

IP Wireless Access in Vehicular Environments (IPWAVE): Problem Statement
                             and Use Cases
               draft-ietf-ipwave-vehicular-networking-03
               draft-ietf-ipwave-vehicular-networking-04

Abstract

   This document discusses the problem statement and use cases on IP-based IP-
   based vehicular networks, which are considered a key component of
   Intelligent Transportation Systems (ITS).  The main topics of
   vehicular networking are vehicle-to-vehicle (V2V), vehicle-to-
   infrastructure (V2I), and vehicle-to-everything (V2X) networking.
   First, this document surveys use cases using V2V, V2I, and V2X
   networking.  Second, this document it analyzes current proposed protocols for IP-based
   vehicular networking and general problems highlights the limitations and difficulties
   found on those current protocols.  Third, this document does it presents a problem exploration
   for key aspects in IP-
   based IP-based vehicular networking, such as IPv6 over IEEE 802.11-OCB, IPv6
   Neighbor Discovery, Mobility Management, Vehicle Identities
   Management, Multihop V2X Communications, Multicast, DNS Naming
   Services, Service Discovery, IPv6 over Cellular Networks, Security and Security & Privacy.  For
   each key aspect, this document discusses a problem statement to
   analyze the gap between the state-of-the-art techniques and
   requirements in IP-based vehicular networking.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.1.  V2V . . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.2.  V2I . . . . . . . . . . . . . . . . . . . . . . . . . . .   6
     3.3.  V2X . . . . . . . . . . . . . . . . . . . . . . . . . . .   7
   4.  Analysis for Current Protocols  . . . . . . . . . . . . . . .   7
     4.1.  Current Protocols for Vehicular Networking  . . . . . . .   7
       4.1.1.  IPv6 over 802.11-OCB  . . . . . . . . . . . . . . . .   7
       4.1.2.  IP Address Autoconfiguration  . . . . . . . . . . . .   7
       4.1.2.   8
       4.1.3.  Routing . . . . . . . . . . . . . . . . . . . . . . .   8
       4.1.3.
       4.1.4.  Mobility Management . . . . . . . . . . . . . . . . .   8
       4.1.4.
       4.1.5.  DNS Naming Service  . . . . . . . . . . . . . . . . .   8
       4.1.5.   9
       4.1.6.  Service Discovery . . . . . . . . . . . . . . . . . .   8
       4.1.6.   9
       4.1.7.  Security and Privacy  . . . . . . . . . . . . . . . .   9
     4.2.  General Problems  . . . . . . . . . . . . . . . . . . . .   9
       4.2.1.  Vehicular Network Architecture  . . . . . . . . . . .   9
       4.2.2.  Latency . . . . . . . . . . . . . . . . . . . . . . .  14
       4.2.3.  Security  . . . . . . . . . . . . . . . . . . . . . .  14
       4.2.4.  Pseudonym Handling  . . . . . . . . . . . . . . . . .  14
   5.  Problem Exploration . . . . . . . . . . . . . . . . . . . . .  14
     5.1.  IPv6 over IEEE 802.11-OCB . . . . . . . . . . . . . . . .  15
     5.2.  Neighbor Discovery  . . . . . . . . . . . . . . . . . . .  15
       5.2.1.
       5.1.1.  Link Model  . . . . . . . . . . . . . . . . . . . . .  15
       5.2.2.
       5.1.2.  MAC Address Pseudonym . . . . . . . . . . . . . . . .  16
       5.2.3.  15
       5.1.3.  Prefix Dissemination/Exchange . . . . . . . . . . . .  16
       5.2.4.
       5.1.4.  Routing . . . . . . . . . . . . . . . . . . . . . . .  16
     5.3.
     5.2.  Mobility Management . . . . . . . . . . . . . . . . . . .  16
     5.4.  Vehicle Identity Management
     5.3.  Security and Privacy  . . . . . . . . . . . . . . .  17
     5.5.  Multihop V2X . . .  17
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  17
     5.6.  Multicast
   7.  Informative References  . . . . . . . . . . . . . . . . . . .  17
   Appendix A.  Relevant Work Items to IPWAVE  . . . . .  17
     5.7.  DNS Naming Services and Service Discovery . . . . . .  25
     A.1.  Vehicle Identity Management . .  17
     5.8.  IPv6 over Cellular Networks . . . . . . . . . . . . .  25
     A.2.  Multihop V2X  . .  18
       5.8.1.  Cellular V2X (C-V2X) Using 4G-LTE . . . . . . . . . .  19
       5.8.2.  Cellular V2X (C-V2X) Using 5G . . . . . . . . . .  25
     A.3.  Multicast . .  19
     5.9.  Security and Privacy . . . . . . . . . . . . . . . . . .  19
   6.  Security Considerations . . . .  25
     A.4.  DNS Naming Services and Service Discovery . . . . . . . .  26
     A.5.  IPv6 over Cellular Networks . . . . . . . . . . . . . . .  20
   7.  Informative References  26
       A.5.1.  Cellular V2X (C-V2X) Using 4G-LTE . . . . . . . . . .  26
       A.5.2.  Cellular V2X (C-V2X) Using 5G . . . . . . . . . . . .  20  27
   Appendix A.  Acknowledgments  . B.  Changes from draft-ietf-ipwave-vehicular-
                networking-03  . . . . . . . . . . . . . . . . .  28
   Appendix B.  Contributors . .  27
   Appendix C.  Acknowledgments  . . . . . . . . . . . . . . . . . .  28  27
   Appendix C.  Changes from draft-ietf-ipwave-vehicular-
                networking-02 D.  Contributors . . . . . . . . . . . . . . . . . . .  30 .  27
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  30

1.  Introduction

   Vehicular networks have been focused on the driving safety, driving
   efficiency, and entertainment in road networks.  The Federal
   Communications Commission (FCC) in the US allocated wireless channels
   for Dedicated Short-Range Communications (DSRC) [DSRC], service in
   the Intelligent Transportation Systems (ITS) Radio Service in the
   5.850 - 5.925 GHz band (5.9 GHz band).  DSRC-based wireless
   communications can support vehicle-to-vehicle (V2V), vehicle-to-
   infrastructure (V2I), and vehicle-to-everything (V2X) networking.
   Also, the European Union (EU) made a law for radio spectrum for
   safety-related applications of ITS with the frequency band of 5.875 -
   5.905 GHz, which is called Commission Decision 2008/671/EC
   [EU-2008-671-EC].

   For driving safety services based on the DSRC, IEEE has standardized
   Wireless Access in Vehicular Environments (WAVE) standards, such as
   IEEE 802.11p [IEEE-802.11p], IEEE 1609.2 [WAVE-1609.2], IEEE 1609.3
   [WAVE-1609.3], and IEEE 1609.4 [WAVE-1609.4].  Note that IEEE 802.11p
   has been published as IEEE 802.11 Outside the Context of a Basic
   Service Set (OCB) [IEEE-802.11-OCB] in 2012.  Along with these WAVE
   standards, IPv6 and Mobile IP protocols (e.g., MIPv4 and MIPv6) can
   be extended to vehicular networks [RFC2460][RFC5944][RFC6275]. [RFC8200][RFC5944][RFC6275].  Also,
   ETSI has standardized a GeoNetworking (GN) protocol
   [ETSI-GeoNetworking] and a protocol adaptation sub-layer from
   GeoNetworking to IPv6 [ETSI-GeoNetwork-IP].  In addition, ISO has
   standardized a standard specifying the IPv6 network protocols and
   services for Communications Access for Land Mobiles (CALM)
   [ISO-ITS-IPv6].

   This document discusses problem statements and use cases related to
   IP-based vehicular networking for Intelligent Transportation Systems
   (ITS).  This document first surveys the use cases for using V2V and
   V2I
   (ITS), which is IP Wireless Access in Vehicular Environments
   (IPWAVE).  First, it surveys the use cases for using V2V, V2I, and
   V2X networking in the ITS.  Second, for literature review, it
   analyzes proposed protocols for IP-based vehicular networking and
   highlights the limitations and difficulties found on those protocols.
   Third, for problem statement, this
   document deals it presents a problem exploration with critical
   key aspects in vehicular networking, IPWAVE, such as IPv6 over IEEE 802.11-OCB, IPv6 Neighbor Discovery, Mobility
   Management, Vehicle Identities Management, Multihop V2X
   Communications, Multicast, DNS Naming Services, Service Discovery,
   IPv6 over Cellular Networks, Security and Security & Privacy.  For each key aspect, this document it
   discusses a problem statement to analyze the gap between the state-of-the-art state-
   of-the-art techniques and requirements in IP-based vehicular
   networking.  Finally,  Also, it also discusses relevant work items to IPWAVE,
   such as Vehicle Identities Management, Multihop V2X Communications,
   Multicast, DNS Naming Services, Service Discovery, and IPv6 over
   Cellular Networks.  Therefore, with the problem statement, this
   document suggests demanding will open a door to develop key standardization items protocols for the
   deployment of IPWAVE in road environments.  As a consequence, this that
   will make it possible be essential to design a network architecture and protocols
   for IP-based vehicular networking. networks.

2.  Terminology

   This document uses the following definitions:

   o  WAVE: Acronym for "Wireless Access in Vehicular Environments"
      [WAVE-1609.0].

   o  DMM: Acronym for "Distributed Mobility Management"
      [RFC7333][RFC7429].

   o  Road-Side Unit (RSU): A node that has physical communication
      devices (e.g., DSRC, Visible Light Communication, 802.15.4, LTE-
      V2X, etc.) for wireless communications with vehicles and is also
      connected to the Internet as a router or switch for packet
      forwarding.  An RSU is deployed either at an intersection or in a
      road segment.

   o  On-Board Unit (OBU): A node that has a DSRC device for wireless
      communications with other OBUs and RSUs.  An OBU is mounted on a
      vehicle.  It is assumed that a radio navigation receiver (e.g.,
      Global Positioning System (GPS)) is included in a vehicle with an
      OBU for efficient navigation.

   o  Vehicle Detection Loop (or Loop Detector): An inductive device
      used for detecting vehicles passing or arriving at a certain
      point, for instance approaching a traffic light or in motorway
      traffic.  The relatively crude nature of the loop's structure
      means that only metal masses above a certain size are capable of
      triggering the detection.

   o  Traffic Control Center (TCC): A node that maintains road
      infrastructure information (e.g., RSUs, traffic signals, and loop
      detectors), vehicular traffic statistics (e.g., average vehicle
      speed and vehicle inter-arrival time per road segment), and
      vehicle information (e.g., a vehicle's identifier, position,
      direction, speed, and trajectory as a navigation path).  TCC is
      included in a vehicular cloud for vehicular networks.

3.  Use Cases

   This section provides use cases of V2V, V2I, and V2X networking.  The
   use cases of the V2X networking exclude the ones of the V2V and V2I
   networking, but include Vehicle-to-Pedestrian (V2P) and Vehicle-to-
   Device (V2D).

3.1.  V2V

   The use cases of V2V networking discussed in this section include

   o  Context-aware navigation for driving safety and collision
      avoidance;

   o  Cooperative adaptive cruise control in an urban roadway;

   o  Platooning in a highway;

   o  Cooperative environment sensing.

   These four techniques will be important elements for self-driving
   vehicles.

   Context-Aware Safety Driving (CASD) navigator [CASD] can help drivers
   to drive safely by letting the drivers recognize dangerous obstacles
   and situations.  That is, CASD navigator displays obstables or
   neighboring vehicles relevant to possible collisions in real-time
   through V2V networking.  CASD provides vehicles with a class-based
   automatic safety action plan, which considers three situations, such
   as the Line-of-Sight unsafe, Non-Line-of-Sight unsafe and safe
   situations.  This action plan can be performed among vehicles through
   V2V networking.

   Cooperative Adaptive Cruise Control (CACC) [CA-Cuise-Control] helps
   vehicles to adapt their speed autonomously through V2V communication
   among vehicles according to the mobility of their predecessor and
   successor vehicles in an urban roadway or a highway.  CACC can help
   adjacent vehicles to efficiently adjust their speed in a cascade way
   through V2V networking.

   Platooning [Truck-Platooning] allows a series of vehicles (e.g.,
   trucks) to move together with a very short inter-distance.  Trucks
   can use V2V communication in addition to forward sensors in order to
   maintain constant clearance between two consecutive vehicles at very
   short gaps (from 3 meters to 10 meters).  This platooning can
   maximize the throughput of vehicular traffic in a highway and reduce
   the gas consumption because the leading vehicle can help the
   following vehicles to experience less air resistance.

   Cooperative-environment-sensing use cases suggest that vehicles can
   share environment environmental information from various sensors, such as radars,
   LiDARs and cameras, mounted on them with other vehicles and
   pedestrians.  [Automotive-Sensing] introduces a millimeter-wave
   vehicular communication for massive automotive sensing.  Data
   generated by those sensors can be substantially large, and these data
   shall be routed to different destinations.  In addition, from the
   perspective of driverless vehicles, it is expected that driverless
   vehicles can be mixed with driver vehicles.  Through cooperative
   enivronment
   environment sensing, driver vehicles can use enivronment environmental
   information sensed by driverless vehicles for better interaction with
   environments.
   the context.

3.2.  V2I

   The use cases of V2I networking discussed in this section include

   o  Navigation service;

   o  Energy-efficient speed recommendation service;

   o  Accident notification service.

   A navigation service, such as the Self-Adaptive Interactive
   Navigation Tool (called SAINT) [SAINT], using V2I networking
   interacts with TCC for the global road traffic optimization and can
   guide individual vehicles for appropriate navigation paths in real
   time.  The enhanced SAINT (called SAINT+) [SAINTplus] can give the
   fast moving paths for emergency vehicles (e.g., ambulance and fire
   engine) toward accident spots while providing other vehicles with
   efficient detour paths.

   A TCC can recommend an energy-efficient speed to a vehicle driving in
   different traffic environments.  [Fuel-Efficient] studys studies fuel-
   efficient route and speed plans for platooned trucks.

   The emergency communication between accident vehicles (or emergency
   vehicles) and TCC can be performed via either RSU or 4G-LTE networks.
   The First Responder Network Authority (FirstNet) [FirstNet] is
   provided by the US government to establish, operate, and maintain an
   interoperable public safety broadband network for safety and security
   network services, such as emergency calls.  The construction of the
   nationwide FirstNet network requires each state in the US to have a
   Radio Access Network (RAN) that will connect to FirstNet's network
   core.  The current RAN is mainly constructed by 4G-LTE for the
   communication between a vehicle and an infrastructure node (i.e.,
   V2I) [FirstNet-Annual-Report-2017], [FirstNet-Report], but DSRC-based vehicular networks can be used
   for V2I in near future [DSRC].

3.3.  V2X

   The use case of V2X networking discussed in this section is
   pedestrian protection service.

   A pedestrian protection service, such as Safety-Aware Navigation
   Application (called SANA) [SANA], using V2I2P networking can reduce
   the collision of a pedestrian and a vehicle, which have a smartphone,
   in a road network.  Vehicles and pedestrians can communicate with
   each other via an RSU that delivers scheduling information for
   wireless communication to save the smartphones' battery.

4.  Analysis for Current Protocols

4.1.  Current Protocols for Vehicular Networking

   We analyze the current protocols from the follow following aspects:

   o  IPv6 over 802.11-OCB;

   o  IP address autoconfiguration;

   o  Routing;

   o  Mobility management;

   o  DNS naming service;

   o  Service discovery;

   o  Security and privacy.

4.1.1.  IPv6 over 802.11-OCB

   For IPv6 packets transporting over IEEE 802.11-OCB,
   [IPv6-over-802.11-OCB] specifies several details, such as Maximum
   Transmission Unit (MTU), frame format, link-local address, address
   mapping for unicast and multicast, stateless autoconfiguration, and
   subnet structure.  Especially, an Ethernet Adaptation (EA) layer is
   in charge of transforming some parameters between IEEE 802.11 MAC
   layer and IPv6 network layer, which is located between IEEE
   802.11-OCB's logical link control layer and IPv6 network layer.

4.1.2.  IP Address Autoconfiguration

   For IP address autoconfiguration, Fazio et al. proposed a vehicular
   address configuration (VAC) scheme using DHCP where elected leader-
   vehicles provide unique identifiers for IP address configurations
   [Address-Autoconf].  Kato et al. proposed an IPv6 address assignment
   scheme using lane and position information [Address-Assignment].
   Baldessari et al. proposed an IPv6 scalable address autoconfiguration
   scheme called GeoSAC for vehicular networks [GeoSAC].  Wetterwald et
   al. conducted a comprehensive study of the cross-layer identities
   management in vehicular networks using multiple access network
   technologies, which constitutes a fundamental element of the ITS
   architecture [Identity-Management].

4.1.2.

4.1.3.  Routing

   For routing, Tsukada et al. presented a work that aims at combining
   IPv6 networking and a Car-to-Car Network routing protocol (called
   C2CNet) proposed by the Car2Car Communication Consortium (C2C-CC),
   which is an architecture using a geographic routing protocol
   [VANET-Geo-Routing].  Abrougui et al. presented a gateway discovery
   scheme for VANET, called Location-Aided Gateway Advertisement and
   Discovery (LAGAD) mechanism [LAGAD].

4.1.3.

4.1.4.  Mobility Management

   For mobility management, Chen et al. tackled the issue of network
   fragmentation in VANET environments [IP-Passing-Protocol] by
   proposing a protocol that can postpone the time to release IP
   addresses to the DHCP server and select a faster way to get the
   vehicle's new IP address, when the vehicle density is low or the
   speeds of vehicles are varied.  Nguyen et al. proposed a hybrid
   centralized-distributed mobility management called H-DMM to support
   highly mobile vehicles [H-DMM].  [NEMO-LMS] proposed an architecture
   to enable IP mobility for moving networks using a network-based
   mobility scheme based on PMIPv6.  Chen et al. proposed a network
   mobility protocol to reduce handoff delay and maintain Internet
   connectivity to moving vehicles in a highway [NEMO-VANET].  Lee et
   al. proposed P-NEMO, which is a PMIPv6-based IP mobility management
   scheme to maintain the Internet connectivity at the vehicle as a
   mobile network, and provides a make-before-break mechanism when
   vehicles switch to a new access network [PMIP-NEMO-Analysis].  Peng
   et al. proposed a novel mobility management scheme for integration of
   VANET and fixed IP networks [VNET-MM].  Nguyen et al. extended their
   previous works on a vehicular adapted DMM considering a Software-
   Defined Networking (SDN) architecture [SDN-DMM].

4.1.4.

4.1.5.  DNS Naming Service

   For DNS naming service, Multicast DNS (mDNS) [RFC6762] allows devices
   in one-hop communication range to resolve each other's DNS name into
   the corresponding IP address in multicast.  DNS Name
   Autoconfiguration (DNSNA) [ID-DNSNA] proposes a DNS naming service
   for Internet-of-Things (IoT) devices in a large-scale network.

4.1.5.

4.1.6.  Service Discovery

   For service discovery, as a popular existing service discovery
   protocol, DNS-based Service Discovery (DNS-SD) [RFC6763] with mDNS
   [RFC6762] provides service discovery.  Vehicular ND [ID-Vehicular-ND]
   proposes an extension of IPv6 ND for the prefix and service
   discovery.

4.1.6.

4.1.7.  Security and Privacy

   For security and privacy, Fernandez et al. proposed a secure
   vehicular IPv6 communication scheme using Internet Key Exchange
   version 2 (IKEv2) and Internet Protocol Security (IPsec)
   [Securing-VCOMM].  Moustafa et al. proposed a security scheme
   providing authentication, authorization, and accounting (AAA)
   services in vehicular networks [VNET-AAA].

4.2.  General Problems

   This section describes a vehicular network architecture for V2V V2V, V2I,
   and
   V2I V2X communications.  Then it analyzes the limitations of the
   current protocols for vehicular networking.

4.2.1.  Vehicular Network Architecture

   Figure 1 shows an architecture for V2I and V2V networking in a road
   network.  The two RSUs (RSU1 and RSU2) are deployed in the road
   network and are connected to a Vehicular Cloud through the Internet.
   TCC is connected to the Vehicular Cloud and the two vehicles
   (Vehicle1 and Vehicle2) are wirelessly connected to RSU1, and the
   last vehicle (Vehicle3) is wirelessly connected to RSU2.  Vehicle1
   can communicate with Vehicle2 via V2V communication, and Vehicle2 can
   communicate with Vehicle3 via V2V communication.  Vehicle1 can
   communicate with Vehicle3 via RSU1 and RSU2 via V2I communication.

                               *-------------*
                              *               *         .-------.
                             * Vehicular Cloud *<------>|  TCC  |
                              *               *         ._______.
                               *-------------*
                              ^               ^
                              |               |
                              |               |
                              v               v
                      .--------.             .--------.
                      |  RSU1  |<----------->|  RSU2  |
                      .________.             .________.
                      ^        ^                  ^
                      :        :                  :
                      :        :                  :
                      v        v                  v
              .--------.      .--------.      .--------.
              |Vehicle1|=>    |Vehicle2|=>    |Vehicle3|=>
              |        |<....>|        |<....>|        |
              .________.      .________.      .________.

      <----> Wired Link   <....> Wireless Link   => Moving Direction

   Figure 1: A Vehicular Network Architecture for V2I and V2V Networking

   In vehicular networks, unidirectional links exist and must be
   considered for wireless communications.  Also, in the vehicular
   networks, control plane must be separated from data plane for
   efficient mobility management and data forwarding.  ID/Pseudonym
   change for privacy requires a lightweight DAD.  IP tunneling over the
   wireless link should be avoided for performance efficiency.  The
   mobility information of a mobile device (e.g., vehicle), such as
   trajectory, position, speed, and direction, can be used by the mobile
   device and infrastructure nodes (e.g., TCC and RSU) for the
   accommodation of proactive protocols because it is usually equipped
   with a GPS receiver.  Vehicles can use the TCC as its Home Network,
   so the TCC maintains the mobility information of vehicles for
   location management.

                               *-------------*
                              *               *         .-------.
                             * Vehicular Cloud *<------>|  TCC  |
                              *               *         ._______.
                               *-------------*
                              ^               ^
                              |               |
                              |               |
                              v               v
                      .--------.             .--------.
                      |  RSU1  |<----------->|  RSU2  |
                      .________.             .________.
                      ^        ^                  ^
                      :        :                  :
                      :        :                  :
                      v        v                  v
              .--------.      .--------.      .--------.
              |Vehicle1|=>    |Vehicle2|=>    |Vehicle3|=>
              |        |<....>|        |<....>|        |
              .________.      .________.      .________.

      <----> Wired Link   <....> Wireless Link   => Moving Direction

   Figure 1: A Vehicular Network Architecture for V2I and V2V Networking

   Cespedes et al. proposed a vehicular IP in WAVE called VIP-WAVE for
   I2V and V2I networking [VIP-WAVE].  The standard WAVE does not
   support both seamless communications for Internet services and multi-
   hop communications between a vehicle and an infrastructure node
   (e.g., RSU), either.  To overcome these limitations of the standard
   WAVE, VIP-WAVE enhances the standard WAVE by the following three
   schemes: (i) an efficient mechanism for the IPv6 address assignment
   and DAD, (ii) on-demand IP mobility based on Proxy Mobile IPv6
   (PMIPv6), and (iii) one-hop and two-hop communications for I2V and
   V2I networking.

   Baccelli et al. provided an analysis of the operation of IPv6 as it
   has been described by the IEEE WAVE standards 1609 [IPv6-WAVE].  This
   analysis confirms that the use of the standard IPv6 protocol stack in
   WAVE is not sufficient.  It recommebs that the IPv6 addressing
   assignment should follow considerations for ad-hoc link models,
   defined in [RFC5889] for nodes' mobility and link variability.

   Petrescu et al. proposed the joint IP networking and radio
   architecture for V2V and V2I communication in [Joint-IP-Networking].
   The proposed architecture considers an IP topology in a similar way
   as a radio link topology, in the sense that an IP subnet would
   correspond to the range of 1-hop vehicular communication.  This
   architecture defines three types of vehicles: Leaf Vehicle, Range
   Extending Vehicle, and Internet Vehicle.

4.2.1.1.  V2I-based Internetworking

   This section discusses the internetworking between a vehicle's moving
   network and an RSU's fixed network.

   As shown in Figure 2, the vehicle's moving network and the RSU's
   fixed network are self-contained networks having multiple subnets and
   having an edge router for the communication with another vehicle or
   RSU.  The method of prefix assignment for each subnet inside the
   vehicle's mobile network and the RSU's fixed network is out of scope
   for this document.  Internetworking between two internal networks via
   either V2I or V2V communication requires an exchange of network
   prefix and other parameters.

   The network parameter discovery collects networking information for
   an IP communication between a vehicle and an RSU or between two
   neighboring vehicles, such as link layer, MAC layer, and IP layer
   information.  The link layer information includes wireless link layer
   parameters, such as wireless media (e.g., IEEE 802.11 OCB, LTE D2D,
   Bluetooth, and LiFi) and a transmission power level.  The MAC layer
   information includes the MAC address of an external network interface
   for the internetworking with another vehicle or RSU.  The IP layer
   information includes the IP address and prefix of an external network
   interface for the internetworking with another vehicle or RSU.

                           (*)<..........>(*)
                            |              | 2001:DB8:1:1::/64
   .------------------------------.  .---------------------------------.
   |                        |     |  |     |                           |
   | .-------. .------. .-------. |  | .-------. .------. .-------.    |
   | | Host1 | |RDNSS1| |Router1| |  | |Router3| |RDNSS2| | Host3 |    |
   | ._______. .______. ._______. |  | ._______. .______. ._______.    |
   |     ^        ^         ^     |  |     ^         ^        ^        |
   |     |        |         |     |  |     |         |        |        |
   |     v        v         v     |  |     v         v        v        |
   | ---------------------------- |  | ------------------------------- |
   | 2001:DB8:10:1::/64 ^         |  |     ^ 2001:DB8:20:1::/64        |
   |                    |         |  |     |                           |
   |                    v         |  |     v                           |
   | .-------.      .-------.     |  | .-------. .-------.   .-------. |
   | | Host2 |      |Router2|     |  | |Router4| |Server1|...|ServerN| |
   | ._______.      ._______.     |  | ._______. ._______.   ._______. |
   |     ^              ^         |  |     ^         ^           ^     |
   |     |              |         |  |     |         |           |     |
   |     v              v         |  |     v         v           v     |
   | ---------------------------- |  | ------------------------------- |
   |  2001:DB8:10:2::/64          |  |       2001:DB8:20:2::/64        |
   .______________________________.  ._________________________________.
      Vehicle1 (Moving Network1)            RSU1 (Fixed Network1)

      <----> Wired Link   <....> Wireless Link   (*) Antenna

     Figure 2: Internetworking between Vehicle Network and RSU Network

   As shown in Figure 2, the vehicle's moving network and the RSU's
   fixed network are self-contained networks having multiple subnets and
   having an edge router for the communication with another vehicle or
   RSU.  The method of prefix assignment for each subnet inside the
   vehicle's mobile network and the RSU's fixed network is out of scope
   for this document.  Internetworking between two internal networks via
   either V2I or V2V communication requires an exchange of network
   prefix and other parameters.

   The network parameter discovery collects networking information for
   an IP communication between a vehicle and an RSU or between two
   neighboring vehicles, such as link layer, MAC layer, and IP layer
   information.  The link layer information includes wireless link layer
   parameters, such as wireless media (e.g., IEEE 802.11-OCB, LTE D2D
   (Device to Device), Bluetooth, and LiFi (Light Fidelity)) and a
   transmission power level.  Note that LiFi is a technology for light-
   based wireless communication between devices in order to transmit
   both data and position.  The MAC layer information includes the MAC
   address of an external network interface for the internetworking with
   another vehicle or RSU.  The IP layer information includes the IP
   address and prefix of an external network interface for the
   internetworking with another vehicle or RSU.

   Once the network parameter discovery and prefix exchange operations
   have been performed, packets can be transmitted between the vehicle's
   moving network and the RSU's fixed network.  DNS services should be
   supported to enable name resolution for hosts or servers residing
   either in the vehicle's moving network or the RSU's fixed network.
   For these DNS services, a recursive DNS server (RDNSS) within each
   internal network of a vehicle or RSU can be used for the hosts or
   servers.

   Figure 2 shows internetworking between the vehicle's moving network
   and the RSU's fixed network.  There exists an internal network
   (Moving Network1) inside Vehicle1.  Vehicle1 has the DNS Server
   (RDNSS1), the two hosts (Host1 and Host2), and the two routers
   (Router1 and Router2).  There exists another internal network (Fixed
   Network1) inside RSU1.  RSU1 has the DNS Server (RDNSS2), one host
   (Host3), the two routers (Router3 and Router4), and the collection of
   servers (Server1 to ServerN) for various services in the road
   networks, such as the emergency notification and navigation.
   Vehicle1's Router1 (called mobile router) and RSU1's Router3 (called
   fixed router) use 2001:DB8:1:1::/64 for an external link (e.g., DSRC)
   for I2V networking.

4.2.1.2.  V2V-based Internetworking

   This section discusses the internetworking between the moving
   networks of two neighboring vehicles in vehicles.

   Figure 3. 3 shows internetworking between the moving networks of two
   neighboring vehicles.  There exists an internal network (Moving
   Network1) inside Vehicle1.  Vehicle1 has the DNS Server (RDNSS1), the
   two hosts (Host1 and Host2), and the two routers (Router1 and
   Router2).  There exists another internal network (Moving Network2)
   inside Vehicle2.  Vehicle2 has the DNS Server (RDNSS2), the two hosts
   (Host3 and Host4), and the two routers (Router3 and Router4).
   Vehicle1's Router1 (called mobile router) and Vehicle2's Router3
   (called mobile router) use 2001:DB8:1:1::/64 for an external link
   (e.g., DSRC) for V2V networking.

                           (*)<..........>(*)
                            |              | 2001:DB8:1:1::/64
   .------------------------------.  .---------------------------------.
   |                        |     |  |     |                           |
   | .-------. .------. .-------. |  | .-------. .------. .-------.    |
   | | Host1 | |RDNSS1| |Router1| |  | |Router3| |RDNSS2| | Host3 |    |
   | ._______. .______. ._______. |  | ._______. .______. ._______.    |
   |     ^        ^         ^     |  |     ^         ^        ^        |
   |     |        |         |     |  |     |         |        |        |
   |     v        v         v     |  |     v         v        v        |
   | ---------------------------- |  | ------------------------------- |
   | 2001:DB8:10:1::/64 ^         |  |     ^ 2001:DB8:30:1::/64        |
   |                    |         |  |     |                           |
   |                    v         |  |     v                           |
   | .-------.      .-------.     |  | .-------.      .-------.        |
   | | Host2 |      |Router2|     |  | |Router4|      | Host4 |        |
   | ._______.      ._______.     |  | ._______.      ._______.        |
   |     ^              ^         |  |     ^              ^            |
   |     |              |         |  |     |              |            |
   |     v              v         |  |     v              v            |
   | ---------------------------- |  | ------------------------------- |
   |  2001:DB8:10:2::/64          |  |       2001:DB8:30:2::/64        |
   .______________________________.  ._________________________________.
      Vehicle1 (Moving Network1)        Vehicle2 (Moving Network2)

      <----> Wired Link   <....> Wireless Link   (*) Antenna

          Figure 3: Internetworking between Two Vehicle Networks

   In Figure 3, the prefix assignment for each subnet inside each
   vehicle's mobile network is done through a prefix delegation
   protocol.

   Figure 3 shows internetworking between the moving networks of two
   neighboring vehicles.  There exists an internal network (Moving
   Network1) inside Vehicle1.  Vehicle1 has the DNS Server (RDNSS1), the
   two hosts (Host1 and Host2), and the two routers (Router1 and
   Router2).  There exists another internal network (Moving Network2)
   inside Vehicle2.  Vehicle2 has the DNS Server (RDNSS2), the two hosts
   (Host3 and Host4), and the two routers (Router3 and Router4).
   Vehicle1's Router1 (called mobile router) and Vehicle2's Router3
   (called mobile router) use 2001:DB8:1:1::/64 for an external link
   (e.g., DSRC) for V2V networking.

   The differences between IPWAVE (including Vehicular Ad Hoc Networks
   (VANET)) and Mobile Ad Hoc Networks (MANET) are as follows:

   o  IPWAVE is not power-constrained operation;

   o  Traffic can be sourced or sinked outside of IPWAVE;

   o  IPWAVE shall support both distributed and centralized operations;

   o  No "sleep" period operation is required for energy saving.

4.2.2.  Latency

   The communication delay (i.e., latency) between two vehicular nodes
   (vehicle and RSU) should be bounded to a certain threshold.  For IP-
   based safety applications (e.g., context-aware navigation, adaptive
   cruise control, and platooning) in vehicular network, this bounded
   data delivery is critical.  The real implementations for such
   applications are not available, so the feasibility of IP-based safety
   applications is not tested yet.

4.2.3.  Security

   Security protects vehicles roaming in road networks from the attacks
   of malicious vehicular nodes, which are controlled by hackers.  For
   safety applications, the cooperation among vehicles is assumed.
   Malicious vehicular nodes may disseminate wrong driving information
   (e.g., location, speed, and direction) to make driving be unsafe.
   Sybil attack, which tries to illude a vehicle with multiple false
   identities, disturbs a vehicle in taking a safe maneuver.
   Applications on IP-based vehicular networking, which are resilient to
   such a sybil attack, are not developed and tested yet.

4.2.4.  Pseudonym Handling

   For the protection of privacy, pseudonym for a vehicle's network
   interface is used, which the interface's identifier is changed
   periodically.  Such a pseudonym affects an IPv6 address based on the
   network interface's identifier, and a transport-layer session with an
   IPv6 address pair.  The pseudonym handling is not implemented and
   test yet for applications on IP-based vehicular networking.

5.  Problem Exploration

   This section discusses key work items for IPWAVE, such as neighbor
   discovery, mobility management, and security & privacy.

5.1.  IPv6 over IEEE 802.11-OCB

   IPv6 over IEEE 802.11-OCB generally follows  Neighbor Discovery

   Neighbor Discovery (ND) [RFC4861] is a core part of the standard IPv6
   procedure.  [IPv6-over-80211-OCB] specifies several details for IPv6
   packets transporting over IEEE 802.11-OCB.  Especially, an Ethernet
   Adaptation (EA) layer is suggested to be inserted between Logical
   Link Control layer and Network layer.  The EA layer is mainly in
   charge of transforming some parameters between 802.11 MAC layer and
   IPv6 layer.

5.2.  Neighbor Discovery

   Neighbor Discovery (ND) [RFC4861] is a core part of the IPv6 protocol
   suite.  This section discusses the need protocol
   suite.  This section discusses the need for modifying ND for use with
   vehicular networking (e.g., V2V V2V, V2I, and V2I). V2X).  The vehicles are
   moving fast within the communication coverage of a vehicular node
   (e.g., vehicle and RSU).  The external link between two vehicular
   nodes can be used for vehicular networking, as shown in Figure 2 and
   Figure 3.

   ND time-related parameters such as router lifetime and Neighbor
   Advertisement (NA) interval should be adjusted for high-speed
   vehicles and vehicle density.  As vehicles move faster, the NA
   interval should decrease for the NA messages to reach the neighboring
   vehicles promptly.  Also, as vehicle density is higher, the NA
   interval should increase for the NA messages to collide with other NA
   messages with lower collision probability.

5.2.1.

5.1.1.  Link Model

   IPv6 protocols work under certain assumptions for the link model that
   do not necessarily hold in WAVE [IPv6-WAVE].  For instance, some IPv6
   protocols assume symmetry in the connectivity among neighboring
   interfaces.  However, interference and different levels of
   transmission power may cause unidirectional links to appear in a WAVE
   link model.

   Also, in an IPv6 link, it is assumed that all interfaces which are
   configured with the same subnet prefix are on the same IP link.
   Hence, there is a relationship between link and prefix, besides the
   different scopes that are expected from the link-local and global
   types of IPv6 addresses.  Such a relationship does not hold in a WAVE
   link model due to node mobility and highly dynamic topology.

   Thus, IPv6 ND should be extended to support the concept of a link for
   an IPv6 prefix in terms of multicast in VANET.

5.2.2.

5.1.2.  MAC Address Pseudonym

   As the ETSI GeoNetworking, for the sake of security and privacy, an
   ITS station (e.g., vehicle) can use pseudonyms for its network
   interface identities (e.g., MAC address) and the corresponding IPv6
   addresses [Identity-Management].  Whenever the network interface
   identifier changes, the IPv6 address based on the network interface
   identifier should be updated.  For the continuity of an end-to-end
   transport-layer (e.g., TCP, UDP, and SCTP) session, the IP addresses
   of the transport-layer session should be notified to both the end
   points and the packets of the session should be forwarded to their
   destinations with the changed network interface identifier and IPv6
   address.

5.2.3.

5.1.3.  Prefix Dissemination/Exchange

   A vehicle and an RSU can have their internal network, as shown in
   Figure 2 and Figure 3.  In this case, nodes in within the internal
   networks of two vehicular nodes (e.g., vehicle and RSU) want to
   communicate with each other.  For this communication, the network
   prefix dissemination or exchange is required.  It is assumed that a
   vehicular node has an external network interface and its internal
   network.  The standard IPv6 ND needs to be extended for the
   communication between the internal-network vehicular nodes by letting
   each of them know the other side's prefix with a new ND option
   [ID-Vehicular-ND].

5.2.4.

5.1.4.  Routing

   For Neighbor Discovery in vehicular networks (called vehicular ND),
   Ad Hoc routing is required for either unicast or multicast in the
   links in a connected VANET with the same IPv6 prefix [GeoSAC].  Also,
   a rapid DAD should be supported to prevent or reduce IPv6 address
   conflicts in such links.

5.3.

5.2.  Mobility Management

   The seamless connectivity and timely data exchange between two end
   points requires an efficient mobility management including location
   management and handover.  Most of vehicles are equipped with a GPS
   navigator as a dedicated navigation system or a smartphone App. With
   this GPS navigator, an efficient mobility management is possible by
   vehicles can share periodically reporting their current position and trajectory
   (i.e., navigation path) with to TCC.  TCC can predict the future positions
   of the vehicles with their mobility information (i.e., the current
   position, speed, direction, and trajectory). trajectory) for location management.

   With the prediction of the vehicle mobility, TCC supports can support RSUs to
   perform DAD, data packet routing, and horizontal/vertical handover in
   a proactive manner.

5.4.  Vehicle Identity Management

   A  When it is assigned a new IPv6 address belonging
   to a different subnet,a vehicle can have multiple network interfaces using different access
   network technologies [Identity-Management].  These multiple skip the DAD operation, reducing
   IPv6 control traffic overhead.  RSUs can efficiently forward data
   packets from the wired network
   interfaces mean multiple identities.  To identify to a moving destination vehicle with
   multiple indenties, a Vehicle Identification Number (VIN) along
   its trajectory.  RSUs can be used
   as smoothly perform handover for the sake of a globally unique
   moving vehicle identifier.

   To support the seamless connectivity over along its trajectory.

5.3.  Security and Privacy

   Security and privacy are paramount in the multiple identities, a
   cross-layer network architecture is required with vertical handover
   functionality [Identity-Management].

5.5.  Multihop V2I, V2V, and V2X

   Multihop packet forwarding among vehicles
   networking in 802.11-OCB mode shows an
   unfavorable performance due to the common known broadcast-storm
   problem [Broadcast-Storm].  This broadcast-storm problem can vehicular networks.  Only authorized vehicles should be
   mitigated by the coordination (or scheduling) of a cluster head
   allowed to use vehicular networking.  Also, in-vehicle devices and
   mobile devices in a
   connected VANET or vehicle need to communicate with other in-vehicle
   devices and mobile devices in another vehicle, and other servers in
   an RSU in an intersection area, which is a
   coordinator for the access secure way.

   A Vehicle Identification Number (VIN) and a user certificate along
   with in-vehicle device's identifier generation can be used to wireless channels.

5.6.  Multicast

   IP multicast
   efficiently authenticate a vehicle or a user through a road
   infrastructure node (e.g., RSU) connected to an authentication server
   in vehicular network environments is especially useful TCC.  Also, Transport Layer Security (TLS) certificates can be
   used for various services. secure end-to-end vehicle communications.

   For instance, an automobile manufacturer can
   multicast secure V2I communication, a particular group/class/type of vehicles for service
   notification.  As another example, secure channel between a mobile
   router in a vehicle or and a fixed router in an RSU can
   disseminate alert messages should be
   established, as shown in Figure 2.  Also, for secure V2V
   communication, a particular area [Multicast-Alert].

   In general IEEE 802 wireless media, some performance issues about
   multicast are found secure channel between a mobile router in [Multicast-Considerations-802].  Since
   serveral procedures a vehicle
   and functions based on IPv6 use multicast for
   control-plane messages, such a mobile router in another vehicle should be established, as Neighbor Discovery (called ND) and
   Service Discovery, [Multicast-Considerations-802] describes that the
   ND process may fail due
   shown in Figure 3.

   To prevent an adversary from tracking a vehicle with its MAC address
   or IPv6 address, MAC address pseudonym should be provided to unreliable wireless link, causing failure
   of the DAD process.  Also,
   vehicle; that is, each vehicle should periodically update its MAC
   address and the Router Advertisement messages can be
   lost corresponding IPv6 address as suggested in multicasting.

5.7.  DNS Naming Services
   [RFC4086][RFC4941].  Such an update of the MAC and Service Discovery

   When IPv6 addresses
   should not interrupt the end-to-end communications between two
   vehicular nodes communicate with each other with the DNS
   name of the partner node, DNS naming service (i.e., DNS name
   resolution) is required.  As shown in Figure 2 (e.g., vehicle and Figure 3, a
   recursive DNS server (RDNSS) within an internal network can perform
   such DNS name resolution for the sake RSU) in terms of other vehicular nodes.

   A service discovery service is required transport layer.

6.  Security Considerations

   This document discussed security and privacy for an application in a IP-based vehicular node to search
   networking.

   The security and privacy for another application or server key components in another IP-based vehicular node, which resides in either the same internal network or
   the other internal network.  In V2I or V2V
   networking, as shown in
   Figure 2 and Figure 3, such a service as neighor discovery service can and mobility management, needs
   to be
   provided by either DNS-based Service Discovery (DNS-SD) [RFC6763]
   with mDNS [RFC6762] or the vehicular ND with a new option for service
   discovery [ID-Vehicular-ND].

5.8.  IPv6 over Cellular Networks

   IP has been supported in celluar networks since the time of General
   Packet Radio Service (GPRS) analyzed in the 2nd generation cellular networks
   of Global System for Mobile communications (2G-GSM) developed depth.

7.  Informative References

   [Address-Assignment]
              Kato, T., Kadowaki, K., Koita, T., and
   maintained by the 3rd Generation Partnership Project (3GPP).  The 2G K. Sato, "Routing
              and 3G-based radio accesses separate end-user data traffic (User
   Plane) from network transport traffic among network elements
   (Transport Plane).  The two planes run independently Address Assignment using Lane/Position Information in terms of
   addressing
              a Vehicular Ad-hoc Network", IEEE Asia-Pacific Services
              Computing Conference, December 2008.

   [Address-Autoconf]
              Fazio, M., Palazzi, C., Das, S., and the M. Gerla, "Automatic
              IP version.  The Transport Plane forms tunnels to
   transport user data traffic [IPv6-3GPP-Survey].

   The 4G-Long-Term-Evolution (4G-LTE) radio access simplifies the
   complex architecture of GPRS core network by introduing the Evolved
   Packet Core (EPC).  Both 2G/3G and 4G-LTE system use Access Point
   Name (APN) Address Configuration in VANETs", ACM International
              Workshop on Vehicular Inter-Networking, September 2016.

   [Automotive-Sensing]
              Choi, J., Va, V., Gonzalez-Prelcic, N., Daniels, R., R.
              Bhat, C., and R. W. Heath, "Millimeter-Wave Vehicular
              Communication to bridge user data Support Massive Automotive Sensing",
              IEEE Communications Magazine, December 2016.

   [Broadcast-Storm]
              Wisitpongphan, N., K. Tonguz, O., S. Parikh, J., Mudalige,
              P., Bai, F., and outside network.  User traffic is
   transported via Packet Data Protocol (PDP) Contexts V. Sadekar, "Broadcast Storm Mitigation
              Techniques in GPRS, Vehicular Ad Hoc Networks", IEEE Wireless
              Communications, December 2007.

   [CA-Cuise-Control]
              California Partners for Advanced Transportation Technology
              (PATH), "Cooperative Adaptive Cruise Control", [Online]
              Available:
              http://www.path.berkeley.edu/research/automated-and-
              connected-vehicles/cooperative-adaptive-cruise-control,
              2017.

   [CASD]     Shen, Y., Jeong, J., Oh, T., and
   Packet Data Network (PDN) Connections in EPC.  Different traffics at
   a user equipment (UE) side need to connect to different APNs through
   multiple PDP Contexts or PDN Connections.  Each S. Son, "CASD: A
              Framework of the context or the
   connection needs to have its own IP address.

   IPv6 is partially supported Context-Awareness Safety Driving in 2G/3G Vehicular
              Networks", International Workshop on Device Centric Cloud
              (DC2), March 2016.

   [DSRC]     ASTM International, "Standard Specification for
              Telecommunications and 4G-LTE.  In 2G/3G, a UE can
   be allocated an IPv6 address via two different ways, IPv6 Information Exchange Between
              Roadside and IPv4v6
   PDP Contexts.  By IPv4v6 PDP Context, both an IPv4 address Vehicle Systems - 5 GHz Band Dedicated Short
              Range Communications (DSRC) Medium Access Control (MAC)
              and an /64
   IPv6 prefix are allocated.  In 4G-LTE, the IPv6 address allocation
   has a different process compared with that in 2G/3G networks.  The
   major difference is that 4G-LTE builds the IP connectivity at the
   beginning of a UE attachment, whereas the IP connectivity Physical Layer (PHY) Specifications",
              ASTM E2213-03(2010), October 2010.

   [ETSI-GeoNetwork-IP]
              ETSI Technical Committee Intelligent Transport Systems,
              "Intelligent Transport Systems (ITS); Vehicular
              Communications; GeoNetworking; Part 6: Internet
              Integration; Sub-part 1: Transmission of 2G/3G
   networks is created on demand.  All 3GPP networks (i.e., 2G/3G and
   4G-LTE) only support SLAAC address allocation, and do not suggest
   performing DAD.  In addition, 3GPP networks remove link-layer address
   resolution, e.g., ND Protocol for IPv6, due to the assumption that
   the GGSN (Gateway GPRS Support Node) in 2G/3G networks or the P-GW
   (Packet Data Network Gateway) in 4G-LTE network is always the first-
   hop router for a UE.

   Recently, 3GPP has announced a new technical specification, Release
   14 (3GPP-R14), which proposes an architecture enhancements for
   vehicle-to-everything (V2X) services using the modified sidelink
   interface that originally is designed for the LTE Device-to-Device
   (LTE-D2D) communications. 3GPP-R14 regulates that the V2X services
   only support IPv6 implementation. 3GPP is also investigating Packets over
              GeoNetworking Protocols", ETSI EN 302 636-6-1, October
              2013.

   [ETSI-GeoNetworking]
              ETSI Technical Committee Intelligent Transport Systems,
              "Intelligent Transport Systems (ITS); Vehicular
              Communications; GeoNetworking; Part 4: Geographical
              addressing and
   discussing the evolved V2X services in the next generation cellular
   networks, i.e., 5G new radio (5G-NR), forwarding for advanced V2X communications point-to-point and automated vehicles' applications.

5.8.1.  Cellular V2X (C-V2X) Using 4G-LTE

   Before 3GPP-R14, some researchers have studied the potential usage point-to-
              multipoint communications; Sub-part 1: Media-Independent
              Functionality", ETSI EN 302 636-4-1, May 2014.

   [EU-2008-671-EC]
              European Union, "Commission Decision of
   C-V2X communications.  For example, [VMaSC-LTE] explores a multihop
   cluster-based hybrid architecture using both DSRC and LTE for safety
   message dissemination.  Most 5 August 2008 on
              the Harmonised Use of Radio Spectrum in the research consider a short message
   service 5875 - 5905
              MHz Frequency Band for safety instead Safety-related Applications of IP datagram forwarding.  In other C-V2X
   research, the standard IPv6 is assumed.

   The 3GPP technical specification [TS-23285-3GPP] states that both IP
   based and non-IP based V2X messages are supported,
              Intelligent Transport Systems (ITS)", EU 2008/671/EC,
              August 2008.

   [FirstNet]
              U.S. National Telecommunications and only IPv6 is
   supported for IP based messages.  Moreover, [TS-23285-3GPP]
   instructes that a UE autoconfigures a link- local IPv6 address by
   following [RFC4862], but without sending Neighbor Solicitation Information
              Administration (NTIA), "First Responder Network Authority
              (FirstNet)", [Online]
              Available: https://www.firstnet.gov/, 2012.

   [FirstNet-Report]
              First Responder Network Authority, "FY 2017: ANNUAL REPORT
              TO CONGRESS, Advancing Public Safety Broadband
              Communications", FirstNet FY 2017, December 2017.

   [Fuel-Efficient]
              van de Hoef, S., H. Johansson, K., and
   Neighbor Advertisement messages D. V. Dimarogonas,
              "Fuel-Efficient En Route Formation of Truck Platoons",
              IEEE Transactions on Intelligent Transportation Systems,
              January 2018.

   [GeoSAC]   Baldessari, R., Bernardos, C., and M. Calderon, "GeoSAC -
              Scalable Address Autoconfiguration for DAD.

5.8.2.  Cellular V2X (C-V2X) VANET Using 5G

   The emerging services, functions
              Geographic Networking Concepts", IEEE International
              Symposium on Personal, Indoor and applications in automotive
   industry spurs ehhanced V2X (eV2X)-based services in the future 5G
   era.  The 3GPP Technical Report [TS-22886-3GPP] is studying new use
   cases Mobile Radio
              Communications, September 2008.

   [H-DMM]    Nguyen, T. and C. Bonnet, "A Hybrid Centralized-
              Distributed Mobility Management for V2X using 5G Supporting Highly
              Mobile Users", IEEE International Conference on
              Communications, June 2015.

   [ID-DNSNA]
              Jeong, J., Ed., Lee, S., and J. Park, "DNS Name
              Autoconfiguration for Internet of Things Devices", draft-
              jeong-ipwave-iot-dns-autoconf-03 (work in the future.

5.9.  Security progress), July
              2018.

   [ID-Vehicular-ND]
              Jeong, J., Ed., Shen, Y., Jo, Y., Jeong, J., and Privacy

   Security J. Lee,
              "IPv6 Neighbor Discovery for Prefix and privacy are paramount Service Discovery
              in the V2I and V2V networking Vehicular Networks", draft-jeong-ipwave-vehicular-
              neighbor-discovery-03 (work in
   vehicular networks.  Only authorized vehicles should be allowed to
   use the V2I and V2V networking.  Also, in-vehicle devices progress), July 2018.

   [Identity-Management]
              Wetterwald, M., Hrizi, F., and mobile
   devices P. Cataldi, "Cross-layer
              Identities Management in a vehicle need to communicate with other in-vehicle
   devices ITS Stations", The 10th
              International Conference on ITS Telecommunications,
              November 2010.

   [IEEE-802.11-OCB]
              IEEE 802.11 Working Group, "Part 11: Wireless LAN Medium
              Access Control (MAC) and mobile devices in another vehicle, Physical Layer (PHY)
              Specifications", IEEE Std 802.11-2012, February 2012.

   [IEEE-802.11p]
              IEEE 802.11 Working Group, "Part 11: Wireless LAN Medium
              Access Control (MAC) and other servers in
   an RSU Physical Layer (PHY)
              Specifications - Amendment 6: Wireless Access in a secure way.

   A Vehicle Identification Number (VIN) Vehicular
              Environments", IEEE Std 802.11p-2010, June 2010.

   [IP-Passing-Protocol]
              Chen, Y., Hsu, C., and a user certificate along W. Yi, "An IP Passing Protocol for
              Vehicular Ad Hoc Networks with in-vehicle device's identifier generation can be used to
   authenticate a vehicle Network Fragmentation",
              Elsevier Computers & Mathematics with Applications,
              January 2012.

   [IPv6-over-802.11-OCB]
              Petrescu, A., Benamar, N., Haerri, J., Lee, J., and the user through a road infrastructure
   node, such as an RSU connected to an authentication server T.
              Ernst, "Transmission of IPv6 Packets over IEEE 802.11
              Networks operating in TCC.
   Transport Layer Security (TLS) certificates can also be used for
   secure vehicle communications.

   For secure V2I communication, mode Outside the secure channel between Context of a mobile
   router Basic
              Service Set (IPv6-over-80211-OCB)", draft-ietf-ipwave-
              ipv6-over-80211ocb-25 (work in a vehicle progress), June 2018.

   [IPv6-WAVE]
              Baccelli, E., Clausen, T., and a fixed router in an RSU should be
   established, as shown in Figure 2.  Also, R. Wakikawa, "IPv6
              Operation for secure V2V
   communication, the secure channel between a mobile router in a
   vehicle and a mobile router in another vehicle should be established,
   as shown WAVE - Wireless Access in Figure 3.

   The security Vehicular
              Environments", IEEE Vehicular Networking Conference,
              December 2010.

   [ISO-ITS-IPv6]
              ISO/TC 204, "Intelligent Transport Systems -
              Communications Access for vehicular networks should provide vehicles with AAA
   services in an efficient way.  It should consider not only horizontal
   handover, but also vertical handover since vehicles have multiple
   wireless interfaces.

   To prevent an adversary from tracking a vehicle by with its MAC
   address or IPv6 address, each vehicle should periodically update its
   MAC address and the corresponding IPv6 address as suggested in
   [RFC4086][RFC4941].  Such an update of the MAC and Land Mobiles (CALM) - IPv6 addresses
   should not interrupt the communications between two vehicular nodes
   (e.g., vehicle and RSU).

6.  Security Considerations

   This document discussed security and privacy for IP-based vehicular
   networking.

   The security
              Networking", ISO 21210:2012, June 2012.

   [Joint-IP-Networking]
              Petrescu, A., Boc, M., and privacy for key components in vehicular networking,
   such as C. Ibars, "Joint IP address autoconfiguration, routing, mobility management,
   DNS naming service, Networking
              and service discovery, needs to be analyzed in
   depth.

7.  Informative References

   [Address-Assignment]
              Kato, T., Kadowaki, Radio Architecture for Vehicular Networks",
              11th International Conference on ITS Telecommunications,
              August 2011.

   [LAGAD]    Abrougui, K., Koita, T., Boukerche, A., and K. Sato, "Routing R. Pazzi, "Location-Aided
              Gateway Advertisement and Address Assignment using Lane/Position Information in
              a Discovery Protocol for VANets",
              IEEE Transactions on Vehicular Ad-hoc Network", Technology, Vol. 59, No. 8,
              October 2010.

   [Multicast-802]
              Perkins, C., Stanley, D., Kumari, W., and JC. Zuniga,
              "Multicast Considerations over IEEE Asia-Pacific Services
              Computing Conference, December 2008.

   [Address-Autoconf]
              Fazio, M., Palazzi, 802 Wireless Media",
              draft-perkins-intarea-multicast-ieee802-03 (work in
              progress), July 2017.

   [Multicast-Alert]
              Camara, D., Bonnet, C., Das, S., Nikaein, N., and M. Gerla, "Automatic
              IP Address Configuration in VANETs", ACM Wetterwald,
              "Multicast and Virtual Road Side Units for Multi
              Technology Alert Messages Dissemination", IEEE 8th
              International
              Workshop Conference on Vehicular Inter-Networking, September 2016.

   [Automotive-Sensing]
              Choi, J., Va, V., Gonzalez-Prelcic, N., Daniels, R., R.
              Bhat, Mobile Ad-Hoc and Sensor
              Systems, October 2011.

   [NEMO-LMS]
              Soto, I., Bernardos, C., Calderon, M., Banchs, A., and R. W. Heath, "Millimeter-Wave Vehicular
              Communication to A.
              Azcorra, "NEMO-Enabled Localized Mobility Support Massive for
              Internet Access in Automotive Sensing", Scenarios",
              IEEE Communications Magazine, December 2016.

   [Broadcast-Storm]
              Wisitpongphan, N., K. Tonguz, O., S. Parikh, J., Mudalige,
              P., Bai, F., May 2009.

   [NEMO-VANET]
              Chen, Y., Hsu, C., and V. Sadekar, "Broadcast Storm Mitigation
              Techniques in C. Cheng, "Network Mobility
              Protocol for Vehicular Ad Hoc Networks", IEEE Wireless
              Communications, December 2007.

   [CA-Cuise-Control]
              California Partners for Advanced Transportation Technology
              (PATH), "Cooperative Adaptive Cruise Control", [Online]
              Available:
              http://www.path.berkeley.edu/research/automated-and-
              connected-vehicles/cooperative-adaptive-cruise-control,
              2017.

   [CASD]     Shen, Y., Jeong,
              Wiley International Journal of Communication Systems,
              November 2014.

   [PMIP-NEMO-Analysis]
              Lee, J., Oh, Ernst, T., and S. Son, "CASD: A
              Framework N. Chilamkurti, "Performance
              Analysis of Context-Awareness Safety Driving in Vehicular
              Networks", International Workshop on Device Centric Cloud
              (DC2), March 2016.

   [DSRC]     ASTM International, "Standard Specification PMIPv6-Based Network Mobility for
              Telecommunications Intelligent
              Transportation Systems", IEEE Transactions on Vehicular
              Technology, January 2012.

   [RFC4086]  Eastlake 3rd, D., Schiller, J., and Information Exchange Between
              Roadside S. Crocker,
              "Randomness Requirements for Security", RFC 4086, June
              2005.

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and Vehicle Systems - 5 GHz Band Dedicated Short
              Range Communications (DSRC) Medium Access Control (MAC) H. Soliman,
              "Neighbor Discovery for IP Version 6 (IPv6)", RFC 4861,
              September 2007.

   [RFC4862]  Thomson, S., Narten, T., and Physical Layer (PHY) Specifications",
              ASTM E2213-03(2010), October 2010.

   [ETSI-GeoNetwork-IP]
              ETSI Technical Committee Intelligent Transport Systems,
              "Intelligent Transport Systems (ITS); Vehicular
              Communications; GeoNetworking; Part 6: Internet
              Integration; Sub-part 1: Transmission of IPv6 Packets over
              GeoNetworking Protocols", ETSI EN 302 636-6-1, October
              2013.

   [ETSI-GeoNetworking]
              ETSI Technical Committee Intelligent Transport Systems,
              "Intelligent Transport Systems (ITS); Vehicular
              Communications; GeoNetworking; Part 4: Geographical
              addressing and forwarding for point-to-point and point-to-
              multipoint communications; Sub-part 1: Media-Independent
              Functionality", ETSI EN 302 636-4-1, May 2014.

   [FirstNet]
              U.S. National Telecommunications and Information
              Administration (NTIA), "First Responder Network Authority
              (FirstNet)", [Online]
              Available: https://www.firstnet.gov/, 2012.

   [FirstNet-Annual-Report-2017]
              First Responder Network Authority, "FY 2017: ANNUAL REPORT
              TO CONGRESS, Advancing Public Safety Broadband
              Communications", FirstNet FY 2017, December 2017.

   [Fuel-Efficient]
              van de Hoef, S., H. Johansson, K., and D. V. Dimarogonas,
              "Fuel-Efficient En Route Formation of Truck Platoons",
              IEEE Transactions on Intelligent Transportation Systems,
              January 2018.

   [GeoSAC]   Baldessari, T. Jinmei, "IPv6 Stateless
              Address Autoconfiguration", RFC 4862, September 2007.

   [RFC4941]  Narten, T., Draves, R., Bernardos, C., and M. Calderon, "GeoSAC -
              Scalable S. Krishnan, "Privacy
              Extensions for Stateless Address Autoconfiguration for VANET Using
              Geographic Networking Concepts", IEEE International
              Symposium on Personal, Indoor and Mobile Radio
              Communications, in
              IPv6", RFC 4941, September 2008.

   [H-DMM]    Nguyen, T. 2007.

   [RFC5889]  Baccelli, E. and C. Bonnet, "A Hybrid Centralized-
              Distributed M. Townsley, "IP Addressing Model in Ad
              Hoc Networks", RFC 5889, September 2010.

   [RFC5944]  Perkins, C., Ed., "IP Mobility Management for Supporting Highly
              Mobile Users", IEEE International Conference on
              Communications, June 2015.

   [ID-DNSNA]
              Jeong, J., Support in IPv4, Revised",
              RFC 5944, November 2010.

   [RFC6275]  Perkins, C., Ed., Lee, S., Johnson, D., and J. Park, "DNS Name
              Autoconfiguration for Internet of Things Devices", draft-
              jeong-ipwave-iot-dns-autoconf-03 (work Arkko, "Mobility
              Support in progress), IPv6", RFC 6275, July
              2018.

   [ID-Vehicular-ND] 2011.

   [RFC6762]  Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
              February 2013.

   [RFC6763]  Cheshire, S. and M. Krochmal, "DNS-Based Service
              Discovery", RFC 6763, February 2013.

   [RFC7333]  Chan, H., Liu, D., Seite, P., Yokota, H., and J. Korhonen,
              "Requirements for Distributed Mobility Management",
              RFC 7333, August 2014.

   [RFC7429]  Liu, D., Zuniga, JC., Seite, P., Chan, H., and CJ.
              Bernardos, "Distributed Mobility Management: Current
              Practices and Gap Analysis", RFC 7429, January 2015.

   [RFC8200]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", RFC 8200, July 2017.

   [SAINT]    Jeong, J., Ed., Jeong, H., Lee, E., Oh, T., and D. Du, "SAINT:
              Self-Adaptive Interactive Navigation Tool for Cloud-Based
              Vehicular Traffic Optimization", IEEE Transactions on
              Vehicular Technology, Vol. 65, No. 6, June 2016.

   [SAINTplus]
              Shen, Y., Jo, Y., Lee, J., Jeong, H., Jeong, J., and J. Lee,
              "IPv6 Neighbor Discovery for Prefix E., and D.
              Du, "SAINT+: Self-Adaptive Interactive Navigation Tool+
              for Emergency Service Discovery Delivery Optimization",
              IEEE Transactions on Intelligent Transportation Systems,
              June 2017.

   [SANA]     Hwang, T. and J. Jeong, "SANA: Safety-Aware Navigation
              Application for Pedestrian Protection in Vehicular
              Networks", draft-jeong-ipwave-vehicular-
              neighbor-discovery-03 (work Springer Lecture Notes in progress), July 2018.

   [Identity-Management]
              Wetterwald, M., Hrizi, F., Computer Science
              (LNCS), Vol. 9502, December 2015.

   [SDN-DMM]  Nguyen, T., Bonnet, C., and P. Cataldi, "Cross-layer
              Identities J. Harri, "SDN-based
              Distributed Mobility Management in ITS Stations", The 10th
              International Conference on ITS Telecommunications,
              November 2010.

   [IEEE-802.11-OCB] for 5G Networks",
              IEEE 802.11 Working Group, "Part 11: Wireless LAN Medium
              Access Control (MAC) Communications and Physical Layer (PHY)
              Specifications", IEEE Std 802.11-2012, February 2012.

   [IEEE-802.11p]
              IEEE 802.11 Working Group, "Part 11: Wireless LAN Medium
              Access Control (MAC) Networking Conference,
              April 2016.

   [Securing-VCOMM]
              Fernandez, P., Santa, J., Bernal, F., and Physical Layer (PHY)
              Specifications - Amendment 6: Wireless Access in A. Skarmeta,
              "Securing Vehicular
              Environments", IPv6 Communications",
              IEEE Std 802.11p-2010, June 2010.

   [IP-Passing-Protocol]
              Chen, Y., Hsu, C., Transactions on Dependable and W. Yi, "An IP Passing Protocol for
              Vehicular Ad Hoc Networks with Network Fragmentation",
              Elsevier Computers & Mathematics with Applications, Secure Computing,
              January 2012.

   [IPv6-3GPP-Survey]
              Soininen, J. and J. Korhonen, "Survey 2016.

   [TR-22.886-3GPP]
              3GPP, "Study on Enhancement of IPv6 3GPP Support in for 5G V2X
              Services", 3GPP Specifications and Implementations",
              IEEE Communications Surveys & Tutorials, January 2015.

   [IPv6-over-80211-OCB]
              Petrescu, A., Benamar, N., Haerri, J., Lee, J., TS 22.886, June 2018.

   [Truck-Platooning]
              California Partners for Advanced Transportation Technology
              (PATH), "Automated Truck Platooning", [Online] Available:
              http://www.path.berkeley.edu/research/automated-and-
              connected-vehicles/truck-platooning, 2017.

   [TS-23.285-3GPP]
              3GPP, "Architecture Enhancements for V2X Services", 3GPP
              TS 23.285, June 2018.

   [VANET-Geo-Routing]
              Tsukada, M., Jemaa, I., Menouar, H., Zhang, W., Goleva,
              M., and T. Ernst, "Transmission of "Experimental Evaluation for IPv6 Packets over
              VANET Geographic Routing", IEEE 802.11
              Networks operating in mode Outside the Context of a Basic
              Service Set (IPv6-over-80211-OCB)", draft-ietf-ipwave-
              ipv6-over-80211ocb-25 (work in progress), June 2018.

   [IPv6-WAVE]
              Baccelli, E., Clausen, T., and R. Wakikawa, "IPv6
              Operation for WAVE - International Wireless Access in Vehicular
              Environments", IEEE Vehicular Networking Conference,
              December 2010.

   [ISO-ITS-IPv6]
              ISO/TC 204, "Intelligent Transport Systems -
              Communications Access for Land Mobiles (CALM) - IPv6
              Networking", ISO 21210:2012, and Mobile Computing Conference, June 2012.

   [Joint-IP-Networking]
              Petrescu, A., Boc, M., 2010.

   [VIP-WAVE]
              Cespedes, S., Lu, N., and C. Ibars, "Joint X. Shen, "VIP-WAVE: On the
              Feasibility of IP Networking
              and Radio Architecture for Communications in 802.11p Vehicular
              Networks",
              11th International Conference IEEE Transactions on ITS Telecommunications,
              August 2011.

   [LAGAD]    Abrougui, K., Boukerche, A., Intelligent Transportation
              Systems, March 2013.

   [VMaSC-LTE]
              Ucar, S., Ergen, S., and R. Pazzi, "Location-Aided
              Gateway Advertisement O. Ozkasap, "Multihop-Cluster-
              Based IEEE 802.11p and Discovery Protocol LTE Hybrid Architecture for VANets", VANET
              Safety Message Dissemination", IEEE Transactions on
              Vehicular Technology, Vol. 59, No. 8,
              October 2010.

   [Multicast-Alert]
              Camara, D., Bonnet, C., Nikaein, N., and M. Wetterwald,
              "Multicast and Virtual Road Side Units for Multi
              Technology Alert Messages Dissemination", IEEE 8th
              International Conference on Mobile Ad-Hoc and Sensor
              Systems, October 2011.

   [Multicast-Considerations-802]
              Perkins, C., Stanley, D., Kumari, W., April 2016.

   [VNET-AAA]
              Moustafa, H., Bourdon, G., and JC. Zuniga,
              "Multicast Considerations over IEEE 802 Wireless Media",
              draft-perkins-intarea-multicast-ieee802-03 (work in
              progress), July 2017.

   [NEMO-LMS]
              Soto, I., Bernardos, C., Calderon, M., Banchs, A., Y. Gourhant, "Providing
              Authentication and A.
              Azcorra, "NEMO-Enabled Localized Mobility Support for
              Internet Access Control in Automotive Scenarios",
              IEEE Communications Magazine, Vehicular Network
              Environment", IFIP TC-11 International Information
              Security Conference, May 2009.

   [NEMO-VANET]
              Chen, Y., Hsu, C., 2006.

   [VNET-MM]  Peng, Y. and C. Cheng, "Network J. Chang, "A Novel Mobility
              Protocol Management Scheme
              for Integration of Vehicular Ad Hoc Networks and Fixed IP
              Networks",
              Wiley International Journal of Communication Systems,
              November 2014.

   [PMIP-NEMO-Analysis]
              Lee, J., Ernst, T., Springer Mobile Networks and N. Chilamkurti, "Performance
              Analysis of PMIPv6-Based Network Mobility Applications,
              February 2010.

   [WAVE-1609.0]
              IEEE 1609 Working Group, "IEEE Guide for Intelligent
              Transportation Systems", Wireless Access
              in Vehicular Environments (WAVE) - Architecture", IEEE Transactions on Std
              1609.0-2013, March 2014.

   [WAVE-1609.2]
              IEEE 1609 Working Group, "IEEE Standard for Wireless
              Access in Vehicular
              Technology, January 2012.

   [RFC2460]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", RFC 2460, December 1998.

   [RFC4086]  Eastlake 3rd, D., Schiller, J., and S. Crocker,
              "Randomness Requirements Environments - Security Services for Security", RFC 4086, June
              2005.

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W.,
              Applications and H. Soliman,
              "Neighbor Discovery Management Messages", IEEE Std
              1609.2-2016, March 2016.

   [WAVE-1609.3]
              IEEE 1609 Working Group, "IEEE Standard for IP Version 6 (IPv6)", RFC 4861,
              September 2007.

   [RFC4862]  Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
              Address Autoconfiguration", RFC 4862, September 2007.

   [RFC4941]  Narten, T., Draves, R., Wireless
              Access in Vehicular Environments (WAVE) - Networking
              Services", IEEE Std 1609.3-2016, April 2016.

   [WAVE-1609.4]
              IEEE 1609 Working Group, "IEEE Standard for Wireless
              Access in Vehicular Environments (WAVE) - Multi-Channel
              Operation", IEEE Std 1609.4-2016, March 2016.

Appendix A.  Relevant Work Items to IPWAVE

   This section discusses relevant work items to IPWAVE: (i) vehicle
   identity management; (ii) multihop V2X; (iii) multicast; (iv) DNS
   naming services and S. Krishnan, "Privacy
              Extensions service discovery; (v) IPv6 over cellular
   networks.

A.1.  Vehicle Identity Management

   A vehicle can have multiple network interfaces using different access
   network technologies [Identity-Management].  These multiple network
   interfaces mean multiple identities.  To identify a vehicle with
   multiple indenties, a Vehicle Identification Number (VIN) can be used
   as a globally unique vehicle identifier.

   To support the seamless connectivity over the multiple identities, a
   cross-layer network architecture is required with vertical handover
   functionality [Identity-Management].  Also, an AAA service for Stateless Address Autoconfiguration
   multiple identities should be provided to vehicles in
              IPv6", RFC 4941, September 2007.

   [RFC5889]  Baccelli, E. an efficient
   way to allow horizontal handover as well as vertical handover; note
   that AAA stands for Authentication, Authorization, and M. Townsley, "IP Addressing Model Accounting.

A.2.  Multihop V2X

   Multihop packet forwarding among vehicles in Ad
              Hoc Networks", RFC 5889, September 2010.

   [RFC5944]  Perkins, C., Ed., "IP Mobility Support 802.11-OCB mode shows an
   unfavorable performance due to the common known broadcast-storm
   problem [Broadcast-Storm].  This broadcast-storm problem can be
   mitigated by the coordination (or scheduling) of a cluster head in IPv4, Revised",
              RFC 5944, November 2010.

   [RFC6275]  Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
              Support a
   connected VANET or an RSU in IPv6", RFC 6275, July 2011.

   [RFC6762]  Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
              February 2013.

   [RFC6763]  Cheshire, S. and M. Krochmal, "DNS-Based Service
              Discovery", RFC 6763, February 2013.

   [RFC7333]  Chan, H., Liu, D., Seite, P., Yokota, H., and J. Korhonen,
              "Requirements for Distributed Mobility Management",
              RFC 7333, August 2014.

   [RFC7429]  Liu, D., Zuniga, JC., Seite, P., Chan, H., and CJ.
              Bernardos, "Distributed Mobility Management: Current
              Practices and Gap Analysis", RFC 7429, January 2015.

   [SAINT]    Jeong, J., Jeong, H., Lee, E., Oh, T., and D. Du, "SAINT:
              Self-Adaptive Interactive Navigation Tool an intersection area, which is a
   coordinator for Cloud-Based
              Vehicular Traffic Optimization", IEEE Transactions on
              Vehicular Technology, Vol. 65, No. 6, June 2016.

   [SAINTplus]
              Shen, Y., Lee, J., Jeong, H., Jeong, J., Lee, E., and D.
              Du, "SAINT+: Self-Adaptive Interactive Navigation Tool+ the access to wireless channels.

A.3.  Multicast

   IP multicast in vehicular network environments is especially useful
   for Emergency Service Delivery Optimization",
              IEEE Transactions on Intelligent Transportation Systems,
              June 2017.

   [SANA]     Hwang, T. and J. Jeong, "SANA: Safety-Aware Navigation
              Application various services.  For instance, an automobile manufacturer can
   multicast a particular group/class/type of vehicles for Pedestrian Protection service
   notification.  As another example, a vehicle or an RSU can
   disseminate alert messages in Vehicular
              Networks", Springer Lecture Notes a particular area [Multicast-Alert].

   In general IEEE 802 wireless media, some performance issues about
   multicast are found in Computer Science
              (LNCS), Vol. 9502, December 2015.

   [SDN-DMM]  Nguyen, T., Bonnet, C., [Multicast-802].  Since serveral procedures
   and J. Harri, "SDN-based
              Distributed Mobility Management functions based on IPv6 use multicast for 5G Networks",
              IEEE Wireless Communications control-plane messages,
   such as Neighbor Discovery (called ND) and Networking Conference,
              April 2016.

   [Securing-VCOMM]
              Fernandez, P., Santa, J., Bernal, F., Service Discovery,
   [Multicast-802] describes that the ND process may fail due to
   unreliable wireless link, causing failure of the DAD process.  Also,
   the Router Advertisement messages can be lost in multicasting.

A.4.  DNS Naming Services and A. Skarmeta,
              "Securing Vehicular IPv6 Communications",
              IEEE Transactions on Dependable Service Discovery

   When two vehicular nodes communicate with each other with the DNS
   name of the partner node, DNS naming service (i.e., DNS name
   resolution) is required.  As shown in Figure 2 and Secure Computing,
              January 2016.

   [Truck-Platooning]
              California Partners Figure 3, a
   recursive DNS server (called RDNSS) within an internal network can
   perform such DNS name resolution for Advanced Transportation Technology
              (PATH), "Automated Truck Platooning", [Online] Available:
              http://www.path.berkeley.edu/research/automated-and-
              connected-vehicles/truck-platooning, 2017.

   [TS-22886-3GPP]
              3GPP, "Study on Enhancement the sake of other vehicular
   nodes.

   A service discovery service is required for an application in a
   vehicular node to search for another application or server in another
   vehicular node, which resides in either the same internal network or
   the other internal network.  In V2I or V2V networking, as shown in
   Figure 2 and Figure 3, such a service discovery service can be
   provided by either DNS-based Service Discovery (DNS-SD) [RFC6763]
   with mDNS [RFC6762] or the vehicular ND with a new option for service
   discovery [ID-Vehicular-ND].

A.5.  IPv6 over Cellular Networks

   Recently, 3GPP Support has announced a new technical specification, Release
   14 (3GPP-R14), which proposes an architecture enhancements for 5G V2X
              Services", 3GPP TS 22.886, June 2018.

   [TS-23285-3GPP]
              3GPP, "Architecture Enhancements
   services using the modified sidelink interface that originally is
   designed for the LTE-D2D communications. 3GPP-R14 regulates that the
   V2X Services", services only support IPv6 implementation. 3GPP
              TS 23.285, June 2018.

   [VANET-Geo-Routing]
              Tsukada, M., Jemaa, I., Menouar, H., Zhang, W., Goleva,
              M., is also
   investigating and T. Ernst, "Experimental Evaluation discussing the evolved V2X services in the next
   generation cellular networks, i.e., 5G new radio (5G-NR), for IPv6 over
              VANET Geographic Routing", IEEE International Wireless
              Communications and Mobile Computing Conference, June 2010.

   [VIP-WAVE]
              Cespedes, S., Lu, N.,
   advanced V2X communications and X. Shen, "VIP-WAVE: On automated vehicles' applications.

A.5.1.  Cellular V2X (C-V2X) Using 4G-LTE

   Before 3GPP-R14, some researchers have studied the
              Feasibility potential usage of IP Communications in 802.11p Vehicular
              Networks", IEEE Transactions on Intelligent Transportation
              Systems, March 2013.
   C-V2X communications.  For example, [VMaSC-LTE]
              Ucar, S., Ergen, S., and O. Ozkasap, "Multihop-Cluster-
              Based IEEE 802.11p explores a multihop
   cluster-based hybrid architecture using both DSRC and LTE Hybrid Architecture for VANET
              Safety Message Dissemination", IEEE Transactions on
              Vehicular Technology, April 2016.

   [VNET-AAA]
              Moustafa, H., Bourdon, G., and Y. Gourhant, "Providing
              Authentication and Access Control in Vehicular Network
              Environment", IFIP TC-11 International Information
              Security Conference, May 2006.

   [VNET-MM]  Peng, Y. safety
   message dissemination.  Most of the research consider a short message
   service for safety instead of IP datagram forwarding.  In other C-V2X
   research, the standard IPv6 is assumed.

   The 3GPP technical specification [TS-23.285-3GPP] states that both IP
   based and J. Chang, "A Novel Mobility Management Scheme
              for Integration of Vehicular Ad Hoc Networks non-IP based V2X messages are supported, and Fixed only IPv6 is
   supported for IP
              Networks", Springer Mobile Networks based messages.  Moreover, [TS-23.285-3GPP]
   instructs that a UE autoconfigures a link- local IPv6 address by
   following [RFC4862], but without sending Neighbor Solicitation and Applications,
              February 2010.

   [WAVE-1609.0]
              IEEE 1609 Working Group, "IEEE Guide
   Neighbor Advertisement messages for Wireless Access DAD.

A.5.2.  Cellular V2X (C-V2X) Using 5G

   The emerging services, functions and applications in Vehicular Environments (WAVE) - Architecture", IEEE Std
              1609.0-2013, March 2014.

   [WAVE-1609.2]
              IEEE 1609 Working Group, "IEEE Standard for Wireless
              Access automotive
   industry spurs ehhanced V2X (eV2X)-based services in Vehicular Environments - Security Services for
              Applications and Management Messages", IEEE Std
              1609.2-2016, March 2016.

   [WAVE-1609.3]
              IEEE 1609 Working Group, "IEEE Standard the future 5G
   era.  The 3GPP Technical Report [TR-22.886-3GPP] is studying new use
   cases for Wireless
              Access V2X using 5G in Vehicular Environments (WAVE) the future.

Appendix B.  Changes from draft-ietf-ipwave-vehicular-networking-03

   The following changes are made from draft-ietf-ipwave-vehicular-
   networking-03:

   o  EU wireless channel allocation (frequency band 5.875 - Networking
              Services", IEEE Std 1609.3-2016, April 2016.

   [WAVE-1609.4]
              IEEE 1609 Working Group, "IEEE Standard 5.905 GHz)
      for Wireless
              Access vehicular networking was specified in Section 1.

   o  Relevant work items to IPWAVE is discussed in Vehicular Environments (WAVE) - Multi-Channel
              Operation", IEEE Std 1609.4-2016, March 2016. Appendix A. A as
      follows: (i) vehicle identity management; (ii) multihop V2X; (iii)
      multicast; (iv) DNS naming services and service discovery; (v)
      IPv6 over cellular networks.

Appendix C.  Acknowledgments

   This work was supported by Basic Science Research Program through the
   National Research Foundation of Korea (NRF) funded by the Ministry of
   Education (2017R1D1A1B03035885).

   This work was supported in part by Global Research Laboratory Program
   through the NRF funded by the Ministry of Science and ICT (MSIT)
   (NRF-2013K1A1A2A02078326) and by the DGIST R&D Program of the MSIT
   (18-EE-01).

   This work was supported in part by the French research project
   DataTweet (ANR-13-INFR-0008) and in part by the HIGHTS project funded
   by the European Commission I (636537-H2020).

Appendix B. D.  Contributors

   This document is a group work of IPWAVE working group, greatly
   benefiting from inputs and texts by Rex Buddenberg (Naval
   Postgraduate School), Thierry Ernst (YoGoKo), Bokor Laszlo (Budapest
   University of Technology and Economics), Jose Santa Lozanoi
   (Universidad of Murcia), Richard Roy (MIT), and Francois Simon
   (Pilot). (Pilot),
   and Sri Gundavelli (Cisco).  The authors sincerely appreciate their
   contributions.

   The following are co-authors of this document:

   Nabil Benamar
   Department of Computer Sciences
   High School of Technology of Meknes
   Moulay Ismail University
   Morocco

   Phone: +212 6 70 83 22 36
   EMail: benamar73@gmail.com

   Sandra Cespedes
   Department of Electrical Engineering
   Universidad de Chile
   Av.  Tupper 2007, Of. 504
   Santiago, 8370451
   Chile

   Phone: +56 2 29784093
   EMail: scespede@niclabs.cl

   Jerome Haerri
   Communication Systems Department
   EURECOM
   Sophia-Antipolis
   France

   Phone: +33 4 93 00 81 34
   EMail: jerome.haerri@eurecom.fr

   Dapeng Liu
   Alibaba
   Beijing, Beijing 100022
   China

   Phone: +86 13911788933
   EMail: max.ldp@alibaba-inc.com

   Tae (Tom) Oh
   Department of Information Sciences and Technologies
   Rochester Institute of Technology
   One Lomb Memorial Drive
   Rochester, NY 14623-5603
   USA

   Phone: +1 585 475 7642
   EMail: Tom.Oh@rit.edu

   Charles E.  Perkins
   Futurewei Inc.
   2330 Central Expressway
   Santa Clara, CA 95050
   USA

   Phone: +1 408 330 4586
   EMail: charliep@computer.org

   Alexandre Petrescu
   CEA, LIST
   CEA Saclay
   Gif-sur-Yvette, Ile-de-France 91190
   France

   Phone: +33169089223
   EMail: Alexandre.Petrescu@cea.fr

   Yiwen Chris Shen
   Department of Computer Science & Engineering
   Sungkyunkwan University
   2066 Seobu-Ro, Jangan-Gu
   Suwon, Gyeonggi-Do 16419
   Republic of Korea

   Phone: +82 31 299 4106
   Fax: +82 31 290 7996
   EMail: chrisshen@skku.edu
   URI: http://iotlab.skku.edu/people-chris-shen.php

   Michelle Wetterwald
   FBConsulting
   21, Route de Luxembourg
   Wasserbillig, Luxembourg L-6633
   Luxembourg

   EMail: Michelle.Wetterwald@gmail.com

Appendix C.  Changes from draft-ietf-ipwave-vehicular-networking-02

   The following changes are made from draft-ietf-ipwave-vehicular-
   networking-02:

   o  The overall structure of the document is reorganized for the
      problem statement for IPWAVE.

Author's Address

   Jaehoon Paul Jeong (editor)
   Department of Software
   Sungkyunkwan University
   2066 Seobu-Ro, Jangan-Gu
   Suwon, Gyeonggi-Do  16419
   Republic of Korea

   Phone: +82 31 299 4957
   Fax:   +82 31 290 7996
   EMail: pauljeong@skku.edu
   URI:   http://iotlab.skku.edu/people-jaehoon-jeong.php