IPWAVE Working Group                                       J. Jeong, Ed.
Internet-Draft                                   Sungkyunkwan University
Intended status: Informational                            March 18,                            30 August 2021
Expires: September 19, 2021 3 March 2022

    IPv6 Wireless Access in Vehicular Environments (IPWAVE): Problem
                        Statement and Use Cases
               draft-ietf-ipwave-vehicular-networking-20
               draft-ietf-ipwave-vehicular-networking-21

Abstract

   This document discusses the problem statement and use cases of
   IPv6-based vehicular networking for Intelligent Transportation
   Systems (ITS).  The main scenarios of vehicular communications are
   vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), and
   vehicle-to-everything (V2X) communications.  First, this document
   explains use cases using V2V, V2I, and V2X networking.  Next, for
   IPv6-based vehicular networks, it makes a gap analysis of current
   IPv6 protocols (e.g., IPv6 Neighbor Discovery, Mobility Management,
   and Security & Privacy), and then enumerates requirements for the
   extensions of those IPv6 protocols for IPv6-based vehicular
   networking.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3   4
   3.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . .   6   7
     3.1.  V2V . . . . . . . . . . . . . . . . . . . . . . . . . . .   7
     3.2.  V2I . . . . . . . . . . . . . . . . . . . . . . . . . . .   9
     3.3.  V2X . . . . . . . . . . . . . . . . . . . . . . . . . . .  11
   4.  Vehicular Networks  . . . . . . . . . . . . . . . . . . . . .  12
     4.1.  Vehicular Network Architecture  . . . . . . . . . . . . .  13  14
     4.2.  V2I-based Internetworking . . . . . . . . . . . . . . . .  17  15
     4.3.  V2V-based Internetworking . . . . . . . . . . . . . . . .  20  18
   5.  Problem Statement . . . . . . . . . . . . . . . . . . . . . .  21  22
     5.1.  Neighbor Discovery  . . . . . . . . . . . . . . . . . . .  22  23
       5.1.1.  Link Model  . . . . . . . . . . . . . . . . . . . . .  23  25
       5.1.2.  MAC Address Pseudonym . . . . . . . . . . . . . . . .  25  27
       5.1.3.  Routing . . . . . . . . . . . . . . . . . . . . . . .  26  27
     5.2.  Mobility Management . . . . . . . . . . . . . . . . . . .  26  28
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  28  30
     6.1.  Security Threats in Neighbor Discovery  . . . . . . . . .  31
     6.2.  Security Threats in Mobility Management . . . . . . . . .  33
     6.3.  Other Threats . . . . . . . . . . . . . . . . . . . . . .  33
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  30  34
   8.  Informative  References  . . . . . . . . . . . . . . . . . . .  30 . . . . . .  34
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  34
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  39
   Appendix A.  Support of Multiple Radio Technologies for V2V . . .  44
   Appendix B.  Support of Multihop V2X Networking . . . . . . . . .  45
   Appendix C.  Support of Mobility Management for V2I . . . . . . .  45
   Appendix D.  Acknowledgments  . . . . . . . . . . . . . . . . . .  38  46
   Appendix B. E.  Contributors . . . . . . . . . . . . . . . . . . . .  38  47
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  40  48

1.  Introduction

   Vehicular networking studies have mainly focused on improving safety
   and efficiency, and also enabling entertainment in vehicular
   networks.  The Federal Communications Commission (FCC) in the US
   allocated wireless channels for Dedicated Short-Range Communications
   (DSRC) [DSRC] in the Intelligent Transportation Systems (ITS) with
   the frequency band of 5.850 - 5.925 GHz (i.e., 5.9 GHz band).  DSRC-
   based wireless communications can support vehicle-to-vehicle (V2V),
   vehicle-to-infrastructure (V2I), and vehicle-to-everything (V2X)
   networking.  The European Union (EU) allocated radio spectrum for
   safety-related and non-safety-related applications of ITS with the
   frequency band of 5.875 - 5.905 GHz, as part of the Commission
   Decision 2008/671/EC [EU-2008-671-EC].

   For direct inter-vehicular wireless connectivity, IEEE has amended
   standard 802.11 (commonly known as Wi-Fi) to enable safe driving
   services based on DSRC for the Wireless Access in Vehicular
   Environments (WAVE) system.  The Physical Layer (L1) and Data Link
   Layer (L2) issues are addressed in IEEE 802.11p [IEEE-802.11p] for
   the PHY and MAC of the DSRC, while IEEE 1609.2 [WAVE-1609.2] covers
   security aspects, IEEE 1609.3 [WAVE-1609.3] defines related services
   at network and transport layers, and IEEE 1609.4 [WAVE-1609.4]
   specifies the multi-channel operation.  IEEE 802.11p was first a
   separate amendment, but was later rolled into the base 802.11
   standard (IEEE 802.11-2012) as IEEE 802.11 Outside the Context of a
   Basic Service Set (OCB) in 2012 [IEEE-802.11-OCB].

   3GPP has standardized Cellular Vehicle-to-Everything (C-V2X)
   communications to support V2X in LTE mobile networks (called LTE V2X)
   and V2X in 5G mobile networks (called 5G V2X) [TS-23.285-3GPP]
   [TR-22.886-3GPP][TS-23.287-3GPP].  With C-V2X, vehicles can directly
   communicate with each other without relay nodes (e.g., eNodeB in LTE
   and gNodeB in 5G).

   Along with these WAVE standards and C-V2X standards, regardless of a
   wireless access technology under the IP stack of a vehicle, vehicular
   networks can operate IP mobility with IPv6 [RFC8200] and Mobile IPv6
   protocols (e.g., Mobile IPv6 (MIPv6) [RFC6275], Proxy MIPv6 (PMIPv6)
   [RFC5213], Distributed Mobility Management (DMM) [RFC7333], Locator/
   ID Network
   Mobility (NEMO) [RFC3963], Locator/ID Separation Protocol (LISP)
   [RFC6830BIS], and Asymmetric Extended Route Optimization (AERO)
   [RFC6706BIS]).  In addition, ISO has approved a standard specifying
   the IPv6 network protocols and services to be used for Communications
   Access for Land Mobiles (CALM)
   [ISO-ITS-IPv6] [ISO-ITS-IPv6-AMD1]. [ISO-ITS-IPv6][ISO-ITS-IPv6-AMD1].

   This document describes use cases and a problem statement about
   IPv6-based vehicular networking for ITS, which is named IPv6 Wireless
   Access in Vehicular Environments (IPWAVE).  First, it introduces the
   use cases for using V2V, V2I, and V2X networking in ITS.  Next, for
   IPv6-based vehicular networks, it makes a gap analysis of current
   IPv6 protocols (e.g., IPv6 Neighbor Discovery, Mobility Management,
   and Security & Privacy), and then enumerates requirements for the
   extensions of those IPv6 protocols, which are tailored to IPv6-based
   vehicular networking.  Thus, this document is intended to motivate
   development of key protocols for IPWAVE.

2.  Terminology

   This document uses the terminology described in [RFC8691].  In
   addition, the following terms are defined below:

   o

   *  Class-Based Safety Plan: A vehicle can make a safety plan by
      classifying the surrounding vehicles into different groups for
      safety purposes according to the geometrical relationship among
      them.  The vehicle groups can be classified as Line-of-Sight
      Unsafe, Non-Line-of-Sight Unsafe, and Safe groups [CASD].

   o

   *  Context-Awareness: A vehicle can be aware of spatial-temporal
      mobility information (e.g., position, speed, direction, and
      acceleration/deceleration) of surrounding vehicles for both safety
      and non-safety uses through sensing or communication [CASD].

   o

   *  DMM: "Distributed Mobility Management" [RFC7333][RFC7429].

   o

   *  Edge Computing (EC): It is the local computing near an access
      network (i.e., edge network) for the sake of vehicles and
      pedestrians.

   o

   *  Edge Computing Device (ECD): It is a computing device (or server)
      for edge computing for the sake of vehicles and pedestrians.

   o

   *  Edge Network (EN): It is an access network that has an IP-RSU for
      wireless communication with other vehicles having an IP-OBU and
      wired communication with other network devices (e.g., routers, IP-
      RSUs, ECDs, servers, and MA).  It may have a Global Positioning
      System (GPS) radio receiver for its position recognition and the
      localization service for the sake of vehicles.

   o

   *  IP-OBU: "Internet Protocol On-Board Unit": An IP-OBU denotes a
      computer situated in a vehicle (e.g., car, bicycle, autobike,
      motor cycle, and a similar one) and a device (e.g., smartphone and
      IoT device).  It has at least one IP interface that runs in IEEE
      802.11-OCB and has an "OBU" transceiver.  Also, it may have an IP
      interface that runs in Cellular V2X (C-V2X) [TS-23.285-3GPP]
      [TR-22.886-3GPP][TS-23.287-3GPP].  It can play a role of a router
      connecting multiple computers (or in-vehicle devices) inside a
      vehicle.  See the definition of the term "OBU" in [RFC8691].

   o

   *  IP-RSU: "IP Roadside Unit": An IP-RSU is situated along the road.
      It has at least two distinct IP-enabled interfaces.  The wireless
      PHY/MAC layer of at least one of its IP-enabled interfaces is
      configured to operate in 802.11-OCB mode.  An IP-RSU communicates
      with the IP-OBU over an 802.11 wireless link operating in OCB
      mode.  Also, it may have an IP interface that runs in C-V2X along
      with an "RSU" transceiver.  An IP-RSU is similar to an Access
      Network Router (ANR), defined in [RFC3753], and a Wireless
      Termination Point (WTP), defined in [RFC5415].  See the definition
      of the term "RSU" in [RFC8691].

   o

   *  LiDAR: "Light Detection and Ranging".  It is a scanning device to
      measure a distance to an object by emitting pulsed laser light and
      measuring the reflected pulsed light.

   o

   *  Mobility Anchor (MA): A node that maintains IPv6 addresses and
      mobility information of vehicles in a road network to support
      their IPv6 address autoconfiguration and mobility management with
      a binding table.  An MA has End-to-End (E2E) connections (e.g.,
      tunnels) with IP-RSUs under its control for the address
      autoconfiguration and mobility management of the vehicles.  This
      MA is similar to a Local Mobility Anchor (LMA) in PMIPv6 [RFC5213]
      for network-based mobility management.

   o

   *  OCB: "Outside the Context of a Basic Service Set - BSS".  It is a
      mode of operation in which a Station (STA) is not a member of a
      BSS and does not utilize IEEE Std 802.11 authentication,
      association, or data confidentiality [IEEE-802.11-OCB].

   o

   *  802.11-OCB: It refers to the mode specified in IEEE Std
      802.11-2016 [IEEE-802.11-OCB] when the MIB attribute
      dot11OCBActivited is 'true'.

   o

   *  Platooning: Moving vehicles can be grouped together to reduce air-
      resistance for energy efficiency and reduce the number of drivers
      such that only the leading vehicle has a driver, and the other
      vehicles are autonomous vehicles without a driver and closely
      follow the leading vehicle [Truck-Platooning].

   o

   *  Traffic Control Center (TCC): A system that manages road
      infrastructure nodes (e.g., IP-RSUs, MAs, traffic signals, and
      loop detectors), and also maintains 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 part of a vehicular cloud for vehicular
      networks.

   o

   *  Vehicle: A Vehicle in this document is a node that has an IP-OBU
      for wireless communication with other vehicles and IP-RSUs.  It
      has a GPS radio navigation receiver for efficient navigation.  Any
      device having an IP-OBU and a GPS receiver (e.g., smartphone and
      tablet PC) can be regarded as a vehicle in this document.

   o

   *  Vehicular Ad Hoc Network (VANET): A network that consists of
      vehicles interconnected by wireless communication.  Two vehicles
      in a VANET can communicate with each other using other vehicles as
      relays even where they are out of one-hop wireless communication
      range.

   o

   *  Vehicular Cloud: A cloud infrastructure for vehicular networks,
      having compute nodes, storage nodes, and network forwarding
      elements (e.g., switch and router).

   o

   *  V2D: "Vehicle to Device".  It is the wireless communication
      between a vehicle and a device (e.g., smartphone and IoT device).

   o

   *  V2I2D: "Vehicle to Infrastructure to Device".  It is the wireless
      communication between a vehicle and a device (e.g., smartphone and
      IoT device) via an infrastructure node (e.g., IP-RSU).

   o

   *  V2I2V: "Vehicle to Infrastructure to Vehicle".  It is the wireless
      communication between a vehicle and another vehicle via an
      infrastructure node (e.g., IP-RSU).

   o

   *  V2I2X: "Vehicle to Infrastructure to Everything".  It is the
      wireless communication between a vehicle and another entity (e.g.,
      vehicle, smartphone, and IoT device) via an infrastructure node
      (e.g., IP-RSU).

   o

   *  V2X: "Vehicle to Everything".  It is the wireless communication
      between a vehicle and any entity (e.g., vehicle, infrastructure
      node, smartphone, and IoT device), including V2V, V2I, and V2D.

   o

   *  VIP: "Vehicular Internet Protocol".  It is an IPv6 extension for
      vehicular networks including V2V, V2I, and V2X.

   o

   *  VMM: "Vehicular Mobility Management".  It is an IPv6-based
      mobility management for vehicular networks.

   o

   *  VND: "Vehicular Neighbor Discovery".  It is an IPv6 ND extension
      for vehicular networks.

   o

   *  VSP: "Vehicular Security and Privacy".  It is an IPv6-based
      security and privacy for vehicular networks.

   o

   *  WAVE: "Wireless Access in Vehicular Environments" [WAVE-1609.0].

3.  Use Cases

   This section explains 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).

   IP is widely used among popular end-user devices (e.g., smartphone
   and tablet) in the Internet.  Applications (e.g., navigator
   application) for those devices can be extended such that the V2V use
   cases in this section can work with IPv6 as a network layer protocol
   and IEEE 802.11-OCB as a link layer protocol.  In addition, IPv6
   security needs to be extended to support those V2V use cases in a
   safe, secure, privacy-preserving way.

   The use cases presented in this section serve as the description and
   motivation for the need to extend IPv6 and its protocols to
   facilitate "Vehicular IPv6".  Section 5 summarizes the overall
   problem statement and IPv6 requirements.  Note that the adjective
   "Vehicular" in this document is used to represent extensions of
   existing protocols such as IPv6 Neighbor Discovery, IPv6 Mobility
   Management (e.g., PMIPv6 [RFC5213] and DMM [RFC7429]), and IPv6
   Security and Privacy Mechanisms rather than new "vehicular-specific"
   functions.

3.1.  V2V

   The use cases of V2V networking discussed in this section include

   o

   *  Context-aware navigation for safe driving and collision avoidance;

   o

   *  Cooperative adaptive cruise control in a roadway;

   o

   *  Platooning in a highway;

   o

   *  Cooperative environment sensing;

   o

   *  Collision avoidance service of end systems of Urban Air Mobility
      (UAM) [UAM-ITS].

   These five techniques will be important elements for autonomous
   vehicles, which may be either terrestrial vehicles or UAM end
   systems.

   Context-Aware Safety Driving (CASD) navigator [CASD] can help drivers
   to drive safely by alerting them to dangerous obstacles and
   situations.  That is, a CASD navigator displays obstacles 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,
   namely, the Line-of-Sight unsafe, Non-Line-of-Sight unsafe, and safe
   situations.  This action plan can be put into action among multiple
   vehicles using V2V networking.

   Cooperative Adaptive Cruise Control (CACC) [CA-Cruise-Control] helps
   individual 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.
   Thus, CACC can help adjacent vehicles to efficiently adjust their
   speed in an interactive way through V2V networking in order to avoid
   a collision.

   Platooning [Truck-Platooning] allows a series (or group) of vehicles
   (e.g., trucks) to follow each other very closely.  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).  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 environmental information (e.g., air pollution, hazards/
   obstacles, slippery areas by snow or rain, road accidents, traffic
   congestion, and driving behaviors of neighboring vehicles) from
   various vehicle-mounted sensors, such as radars, LiDARs, and cameras,
   with other vehicles and pedestrians.  [Automotive-Sensing] introduces
   millimeter-wave vehicular communication for massive automotive
   sensing.  A lot of data can be generated by those sensors, and these
   data typically need to be routed to different destinations.  In
   addition, from the perspective of driverless vehicles, it is expected
   that driverless vehicles can be mixed with driver-operated vehicles.
   Through cooperative environment sensing, driver-operated vehicles can
   use environmental information sensed by driverless vehicles for
   better interaction with the other vehicles and environment.  Vehicles
   can also share their intended maneuvering information (e.g., lane
   change, speed change, ramp in-and-out, cut-in, and abrupt braking)
   with neighboring vehicles.  Thus, this information sharing can help
   the vehicles behave as more efficient traffic flows and minimize
   unnecessary acceleration and deceleration to achieve the best ride
   comfort.

   A collision avoidance service of UAM end systems in air can be
   envisioned as a use case in air vehicular environments.  This use
   case is similar to the context-aware navigator for terrestrial
   vehicles.  Through V2V coordination, those UAM end systems (e.g.,
   drones) can avoid a dangerous situation (e.g., collision) in three-
   dimensional space rather than two-dimensional space for terrestrial
   vehicles.  Also, UAM end systems (e.g., flying car) with only a few
   meters off the ground can communicate with terrestrial vehicles with
   wireless communication technologies (e.g., DSRC, LTE, and C-V2X).
   Thus, V2V means any vehicle to any vehicle, whether the vehicles are
   ground-level or not.

   To encourage more vehicles to participate in this cooperative
   environmental sensing, a reward system will be needed.  Sensing
   activities of each vehicle need to be logged in either a central way
   through a logging server (e.g., TCC) in the vehicular cloud or a
   distributed way (e.g., blockchain [Bitcoin]) through other vehicles
   or infrastructure.  In the case of a blockchain, each sensing message
   from a vehicle can be treated as a transaction and the neighboring
   vehicles can play the role of peers in a consensus method of a
   blockchain [Bitcoin][Vehicular-BlockChain].

   Although a Layer-2 solution can provide a

   To support for multihop
   communications in vehicular networks, the scalability issue related
   to multihop forwarding still remains when vehicles need to
   disseminate or forward packets toward multihop-away destinations.  In
   addition, the IPv6-based approach for V2V as a network layer protocol
   can accommodate multiple radio technologies as MAC protocols, such as
   5G V2X and DSRC.  Therefore, the existing IPv6 protocol can be
   augmented through the addition of an Overlay Multilink Network (OMNI)
   Interface [OMNI] and/or protocol changes in order to support both
   wireless single-hop/multihop V2V communications and multiple radio
   technologies in vehicular networks.  In such a way, vehicles can
   communicate with each other by V2V communications to share either an
   emergency situation or road hazard in a highway having multiple kinds
   of radio technologies, such as 5G V2X and DSRC.

   To support applications of these V2V use cases, applications of these V2V use cases, the required
   functions of IPv6
   such as VND and VSP are prerequisites for include IPv6-based packet exchange and secure, safe
   communication between two vehicles.  For the support of V2V under
   multiple radio technologies (e.g., DSRC and 5G V2X), refer to
   Appendix A.

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;

   o

   *  Electric vehicle (EV) charging service;

   o

   *  UAM navigation service with efficient battery charging.

   A navigation service, for example, the Self-Adaptive Interactive
   Navigation Tool(SAINT) [SAINT], using V2I networking interacts with a
   TCC for the large-scale/long-range road traffic optimization and can
   guide individual vehicles along appropriate navigation paths in real
   time.  The enhanced version of SAINT [SAINTplus] can give fast moving
   paths to emergency vehicles (e.g., ambulance and fire engine) to let
   them reach an accident spot while redirecting other vehicles near the
   accident spot into efficient detour paths.

   Either a TCC or an ECD can recommend an energy-efficient speed to a
   vehicle that depends on its traffic environment and traffic signal
   scheduling [SignalGuru].  For example, when a vehicle approaches an
   intersection area and a red traffic light for the vehicle becomes
   turned on, it needs to reduce its speed to save fuel consumption.  In
   this case, either a TCC or an ECD, which has the up-to-date
   trajectory of the vehicle and the traffic light schedule, can notify
   the vehicle of an appropriate speed for fuel efficiency.
   [Fuel-Efficient] studies fuel-efficient route and speed plans for
   platooned trucks.

   The emergency communication between accident vehicles (or emergency
   vehicles) and a TCC can be performed via either IP-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, e.g., 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
   the FirstNet's network core.  The current RAN is mainly constructed
   using 4G-LTE for the communication between a vehicle and an
   infrastructure node (i.e., V2I) [FirstNet-Report], but it is expected
   that DSRC-based vehicular networks [DSRC] will be available for V2I
   and V2V in the near future.

   An EV charging service with V2I can facilitate the efficient battery
   charging of EVs.  In the case where an EV charging station is
   connected to an IP-RSU, an EV can be guided toward the deck of the EV
   charging station through a battery charging server connected to the
   IP-RSU.  In addition to this EV charging service, other value-added
   services (e.g., air firmware/software update and media streaming) can
   be provided to an EV while it is charging its battery at the EV
   charging station.

   A UAM navigation service with efficient battery charging can plan the
   battery charging schedule of UAM end systems (e.g., drone) for long-
   distance flying [CBDN].  For this battery charging schedule, a UAM
   end system can communicate with an infrastructure node (e.g., IP-RSU)
   toward a cloud server via V2I communications.  This cloud server can
   coordinate the battery charging schedules of multiple UAM end systems
   for their efficient navigation path, considering flight time from
   their current position to a battery charging station, waiting time in
   a waiting queue at the station, and battery charging time at the
   station.

   The existing IPv6 protocol must be augmented through the addition of
   an OMNI interface and/or protocol changes
   in order to support wireless multihop V2I communications in a highway
   where RSUs are sparsely deployed, so a vehicle can reach the wireless
   coverage of an RSU through the multihop data forwarding of
   intermediate vehicles.  Thus, IPv6 needs to be extended for multihop
   V2I communications.

   To support applications of these V2I use cases, the required
   functions of IPv6
   such as VND, VMM, and VSP are prerequisites for include IPv6-based packet exchange, transport-layer
   session continuity, and secure, safe communication between a vehicle
   and a server an infrastructure node (e.g., IP-RSU) in the vehicular cloud. network.

3.3.  V2X

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

   A pedestrian protection service, such as Safety-Aware Navigation
   Application (SANA) [SANA], using V2I2P networking can reduce the
   collision of a vehicle and a pedestrian carrying a smartphone
   equipped with a network device for wireless communication (e.g., Wi-
   Fi) with an IP-RSU.  Vehicles and pedestrians can also communicate
   with each other via an IP-RSU.  An edge computing device behind the
   IP-RSU can collect the mobility information from vehicles and
   pedestrians, compute wireless communication scheduling for the sake
   of them.  This scheduling can save the battery of each pedestrian's
   smartphone by allowing it to work in sleeping mode before the
   communication with vehicles, considering their mobility.

   For Vehicle-to-Pedestrian (V2P), a vehicle can directly communicate
   with a pedestrian's smartphone by V2X without IP-RSU relaying.
   Light-weight mobile nodes such as bicycles may also communicate
   directly with a vehicle for collision avoidance using V2V.

   The existing IPv6 protocol must be augmented through the addition of
   an OMNI interface and/or protocol changes
   in order to support wireless multihop V2X (or V2I2X) or V2I2X communications in
   an urban road network where RSUs are deployed at intersections, so a
   vehicle (or a pedestrian's smartphone) can reach the wireless
   coverage of an RSU through the multihop data forwarding of
   intermediate vehicles (or pedestrians' smartphones). smartphones) as packet
   forwarders.  Thus, IPv6 needs to be extended for multihop V2X (or V2I2X) or
   V2I2X communications.

   To support applications of these V2X use cases, the required
   functions of IPv6
   such as VND, VMM, and VSP are prerequisites for include IPv6-based packet exchange, transport-layer
   session continuity, and secure, safe communication between a vehicle
   and a pedestrian either directly or indirectly via an IP-RSU.

4.  Vehicular Networks

   This section describes an example the context for vehicular network architecture networks supporting
   V2V, V2I, and V2X communications in vehicular networks. communications.  It describes an internal network
   within a vehicle or an edge network (called EN).  It explains not
   only the internetworking between the internal networks of a vehicle
   and an EN via wireless links, but also the internetworking between
   the internal networks of two vehicles via wireless links.

                     Traffic Control Center in Vehicular Cloud
                    *******************************************
+-------------+    *                                           *
|Corresponding|   *             +-----------------+             *
|    Node     |<->*             | Mobility Anchor |             *
+-------------+   *             +-----------------+             *
                  *                      ^                      *
                  *                      |                      *
                   *                     v                     *
                    *******************************************
                    ^                   ^                     ^
                    |                   |                     |
                    |                   |                     |
                    v                   v                     v
              +---------+           +---------+           +---------+
              | IP-RSU1 |<--------->| IP-RSU2 |<--------->| IP-RSU3 |
              +---------+           +---------+           +---------+
                  ^                     ^                    ^
                  :                     :                    :
           +-----------------+ +-----------------+   +-----------------+
           |      : V2I      | |        : V2I    |   |       : V2I     |
           |      v          | |        v        |   |       v         |
+--------+ |   +--------+    | |   +--------+    |   |   +--------+    |
|Vehicle1|===> |Vehicle2|===>| |   |Vehicle3|===>|   |   |Vehicle4|===>|
+--------+<...>+--------+<........>+--------+    |   |   +--------+    |
           V2V     ^         V2V        ^        |   |        ^        |
           |       : V2V     | |        : V2V    |   |        : V2V    |
           |       v         | |        v        |   |        v        |
           |  +--------+     | |   +--------+    |   |    +--------+   |
           |  |Vehicle5|===> | |   |Vehicle6|===>|   |    |Vehicle7|==>|
           |  +--------+     | |   +--------+    |   |    +--------+   |
           +-----------------+ +-----------------+   +-----------------+
                 Subnet1              Subnet2              Subnet3
                (Prefix1)            (Prefix2)            (Prefix3)

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

 Figure 1: An Example Vehicular Network Architecture for V2I and V2V

4.1.  Vehicular Network Architecture

   Figure 1 shows an example vehicular network architecture for V2I and
   V2V in a road network [OMNI]. network.  The vehicular network architecture contains
   vehicles (including IP-OBU), IP-RSUs, Mobility Anchor, Traffic
   Control Center, and Vehicular Cloud as components.  Note that
   the  These components
   are not mandatory, and they can be deployed into vehicular networks
   in various ways.  Some of them (e.g., Mobility Anchor, Traffic
   Control Center, and Vehicular Cloud) may not be needed for the
   vehicular network architecture can be mapped networks according to
   those of an IP-based aeronautical network architecture target use cases in [OMNI], Section 3.

   Existing network architectures, such as
   shown in Figure 2.

        +-------------------+------------------------------------+
        | Vehicular Network | Aeronautical Network               |
        +===================+====================================+
        | IP-RSU            | Access Router (AR)                 |
        +-------------------+------------------------------------+
        | Vehicle (IP-OBU)  | Mobile Node (MN)                   |
        +-------------------+------------------------------------+
        | Moving Network    | End User Network (EUN)             |
        +-------------------+------------------------------------+
        | Mobility Anchor   | Mobility Service Endpoint (MSE)    |
        +-------------------+------------------------------------+
        | Vehicular Cloud   | Internetwork (INET) Routing System |
        +-------------------+------------------------------------+

        Figure 2: Mapping between Vehicular Network Components and
                      Aeronautical Network Components

   These components are not mandatory, and they can be deployed into
   vehicular networks in various ways.  Some of them (e.g., Mobility
   Anchor, Traffic Control Center, and Vehicular Cloud) may not be
   needed for the vehicular networks according to target use cases in
   Section 3.

   An existing network architecture (e.g., an IP-based aeronautical
   network architecture [OMNI][UAM-ITS], a network architecture architectures of
   PMIPv6 [RFC5213], RPL (IPv6 Routing Protocol for Low-Power and a low-power Lossy
   Networks) [RFC6550], and lossy network architecture
   [RFC6550]) OMNI (Overlay Multilink Network Interface)
   [OMNI], can be extended to a vehicular network architecture for
   multihop V2V, V2I, and V2X, as shown in Figure 1.  In a highway
   scenario, a vehicle may not access an RSU directly because of the
   distance of the DSRC coverage (up  Refer to 1 km).  For example,
   Appendix B for the OMNI
   interface and/or detailed discussion on multihop V2X networking by
   RPL (IPv6 Routing Protocol for Low-Power and Lossy
   Networks) [RFC6550] can be extended to support a multihop V2I since a
   vehicle can take advantage of other vehicles OMNI.

   As shown in this figure, IP-RSUs as relay nodes to reach routers and vehicles with IP-OBU
   have wireless media interfaces for VANET.  Furthermore, the RSU.  Also, RPL can be extended wireless
   media interfaces are autoconfigured with a global IPv6 prefix (e.g.,
   2001:DB8:1:1::/64) to support both multihop V2V and
   V2X V2I networking.  Note that
   2001:DB8::/32 is a documentation prefix [RFC3849] for example
   prefixes in the similar way.

   Wireless communications needs to be considered for end systems for
   Urban Air Mobility (UAM) such as flying cars and taxis [UAM-ITS].

   These UAM end systems may have multiple wireless transmission media
   interfaces (e.g., cellular, communications satellite (SATCOM), short-
   range omni-directional interfaces), which are offered by different
   data link service providers.  To support not only the mobility
   management of the UAM end systems, but also the multihop and
   multilink communications of the UAM interfaces, the UAM end systems
   can employ an Overlay Multilink Network (OMNI) interface [OMNI] as a
   virtual Non-Broadcast Multiple Access (NBMA) connection to a serving
   ground domain infrastructure.  This infrastructure can be configured
   over the underlying data links.  The OMNI interface and its link
   model provide a means of multilink, multihop and mobility
   coordination to the legacy IPv6 ND messaging [RFC4861] according to
   the NBMA principle.  Thus, the OMNI link model can support efficient
   UAM internetworking services without additional mobility messaging,
   and without any modification to the IPv6 ND messaging services or
   link model.

   As shown in this figure, IP-RSUs as routers and vehicles with IP-OBU
   have wireless media interfaces for VANET.  Furthermore, the wireless
   media interfaces are autoconfigured with a global IPv6 prefix (e.g.,
   2001:DB8:1:1::/64) to support both V2V and V2I networking.  Note that
   2001:DB8::/32 is a documentation prefix [RFC3849] for example
   prefixes in this document, and also that any routable IPv6 address this document, and also that any routable IPv6 address
   needs to be routable in a VANET and a vehicular network including IP-
   RSUs.

   In Figure 1, three IP-RSUs (IP-RSU1, IP-RSU2, and IP-RSU3) are
   deployed in the road network and are connected with each other
   through the wired networks (e.g., Ethernet).  A Traffic Control
   Center (TCC) is connected to the Vehicular Cloud for the management
   of IP-RSUs and vehicles in the road network.  A Mobility Anchor (MA)
   may be located in the TCC as a mobility management controller.
   Vehicle2, Vehicle3, and Vehicle4 are wirelessly connected to IP-RSU1,
   IP-RSU2, and IP-RSU3, respectively.  The three wireless networks of
   IP-RSU1, IP-RSU2, and IP-RSU3 can belong to three different subnets
   (i.e., Subnet1, Subnet2, and Subnet3), respectively.  Those three
   subnets use three different prefixes (i.e., Prefix1, Prefix2, and
   Prefix3).

   Multiple vehicles under the coverage of an RSU share a prefix just as
   mobile nodes share a prefix of a Wi-Fi access point in a wireless
   LAN.  This is a natural characteristic in infrastructure-based
   wireless networks.  For example, in Figure 1, two vehicles (i.e.,
   Vehicle2, and Vehicle5) can use Prefix 1 to configure their IPv6
   global addresses for V2I communication.  Alternatively, mobile nodes
   can employ an OMNI interface and use a "Bring-Your-Own-Addresses (BYOA)" technique using their
   own IPv6 Unique Local Addresses (ULAs) [RFC4193] over the wireless network without
   requiring
   network, which does not require the messaging (e.g., Duplicate
   Address Detection (DAD)) of IPv6 Stateless Address Autoconfiguration
   (SLAAC) [RFC4862], which uses an on-link prefix provided by the
   (visited) [RFC4862].

   In wireless LAN; this technique is known as "Bring-Your-Own-
   Addresses".

   A single subnet prefix announced by an RSU can span multiple vehicles subnets in VANET.  For example, vehicular networks (e.g., Subnet1 and Subnet2
   in Figure 1, for Prefix 1, three vehicles
   (i.e., Vehicle1, Vehicle2, and Vehicle5) can construct a connected
   VANET.  Also, for Prefix 2, two vehicles (i.e., Vehicle3 and
   Vehicle6) can construct another connected VANET, and for Prefix 3,
   two vehicles (i.e., Vehicle4 and Vehicle7) can construct another
   connected VANET.  Alternatively, each vehicle could employ an OMNI
   interface with their own ULAs such that no topologically-oriented
   subnet prefixes need be announced by the RSU.

   In wireless subnets in vehicular networks (e.g., Subnet1 and Subnet2
   in Figure 1), 1), vehicles can construct a connected VANET (with an
   arbitrary graph topology) and can communicate with each other via V2V
   communication.  Vehicle1 can communicate with Vehicle2 via V2V
   communication, and Vehicle2 can communicate with Vehicle3 via V2V
   communication because they are within the wireless communication
   range of each other.  On the other hand, Vehicle3 can communicate
   with Vehicle4 via the vehicular infrastructure (i.e., IP-RSU2 and IP-
   RSU3) by employing V2I (i.e., V2I2V) communication because they are
   not within the wireless communication range of each other.

   For

   As a basic definition for IPv6 packets transported over IEEE
   802.11-OCB, [RFC8691] specifies several details, including Maximum
   Transmission Unit (MTU), frame format, link-local address, address
   mapping for unicast and multicast, stateless autoconfiguration, and
   subnet structure.

   An
   Ethernet Adaptation (EA) layer is in charge of transforming some
   parameters between the IEEE 802.11 MAC layer and the IPv6 network
   layer, which is located between the IEEE 802.11-OCB's logical link
   control layer and the IPv6 network layer.  This IPv6 over 802.11-OCB
   can be used for both V2V and V2I in IPv6-based vehicular networks.

   An IPv6 mobility solution is needed for the guarantee of
   communication continuity in vehicular networks so that a vehicle's
   TCP session can be continued, or UDP packets can be delivered to a
   vehicle as a destination without loss while it moves from an IP-RSU's
   wireless coverage to another IP-RSU's wireless coverage.  In
   Figure 1, assuming that Vehicle2 has a TCP session (or a UDP session)
   with a corresponding node in the vehicular cloud, Vehicle2 can move
   from IP-RSU1's wireless coverage to IP-RSU2's wireless coverage.  In
   this case, a handover for Vehicle2 needs to be performed by either a
   host-based mobility management scheme (e.g., MIPv6 [RFC6275]) or a
   network-based mobility management scheme (e.g., PMIPv6 [RFC5213] and
   AERO [RFC6706BIS]).

   In the host-based mobility scheme (e.g., MIPv6), an IP-RSU plays a
   role of a home agent.  On the other hand,  This document describes issues in the network-based
   mobility scheme (e.g., PMIPv6, an MA plays a role of a mobility
   management controller such as a Local Mobility Anchor (LMA) for vehicular networks in
   PMIPv6, which also serves vehicles as Section 5.2.

4.2.  V2I-based Internetworking

   This section discusses the internetworking between a home agent, vehicle's
   internal network (i.e., moving network) and an IP-RSU
   plays a role of an access router such as a Mobile Access Gateway
   (MAG) in PMIPv6 [RFC5213]. EN's internal network
   (i.e., fixed network) via V2I communication.  The host-based mobility scheme needs
   client functionality in IPv6 stack internal network of
   a vehicle as a mobile node for
   mobility signaling message exchange between the vehicle and home
   agent.  On the other hand, the network-based mobility scheme does not
   need such a client functionality for a vehicle because the network
   infrastructure node (e.g., MAG in PMIPv6) as a proxy mobility agent
   handles the mobility signaling message exchange is nowadays constructed with the home agent
   (e.g., LMA in PMIPv6) for the sake of the vehicle.

   There are a scalability issue and a route optimization issue in the
   network-based mobility scheme (e.g., PMIPv6) when an MA covers a
   large vehicular network governing Ethernet by many IP-RSUs.  In this case, a
   distributed mobility scheme (e.g., DMM [RFC7429]) automotive
   vendors [In-Car-Network].  Note that an EN can mitigate the
   scalability issue by distributing accommodate multiple MAs
   routers (or switches) and servers (e.g., ECDs, navigation server, and
   DNS server) in the vehicular its internal network.

   A vehicle's internal network such that they are positioned closer often uses Ethernet to vehicles for route
   optimization and bottleneck mitigation in a central MA interconnect
   Electronic Control Units (ECUs) in the
   network-based mobility scheme.  All these mobility approaches (i.e., vehicle.  The internal network
   can support Wi-Fi and Bluetooth to accommodate a host-based mobility scheme, network-based mobility scheme, driver's and
   distributed mobility scheme)
   passenger's mobile devices (e.g., smartphone or tablet).  The network
   topology and subnetting depend on each vendor's network configuration
   for a hybrid approach of a combination
   of them need to provide vehicle and an efficient mobility service EN.  It is reasonable to vehicles
   moving fast and moving along with the relatively predictable
   trajectories along the roadways.

   In vehicular networks, consider the control plane can be separated from
   interaction between the
   data plane for efficient mobility management internal network and data forwarding by
   using the concept of Software-Defined Networking (SDN)
   [RFC7149][DMM-FPC].  Note that Forwarding Policy Configuration (FPC) an external network
   within another vehicle or an EN.

                                                    +-----------------+
                           (*)<........>(*)  +----->| Vehicular Cloud |
        (2001:DB8:1:1::/64) |            |   |      +-----------------+
   +------------------------------+  +---------------------------------+
   |                        v     |  |   v   v                         |
   | +-------+          +-------+ |  | +-------+          +-------+    |
   | | Host1 |          |IP-OBU1| |  | |IP-RSU1|          | Host3 |    |
   | +-------+          +-------+ |  | +-------+          +-------+    |
   |     ^                  ^     |  |     ^                  ^        |
   |     |                  |     |  |     |                  |        |
   |     v                  v     |  |     v                  v        |
   | ---------------------------- |  | ------------------------------- |
   | 2001:DB8:10:1::/64 ^         |  |     ^ 2001:DB8:20:1::/64        |
   |                    |         |  |     |                           |
   |                    v         |  |     v                           |
   | +-------+      +-------+     |  | +-------+ +-------+   +-------+ |
   | | Host2 |      |Router1|     |  | |Router2| |Server1|...|ServerN| |
   | +-------+      +-------+     |  | +-------+ +-------+   +-------+ |
   |     ^              ^         |  |     ^         ^           ^     |
   |     |              |         |  |     |         |           |     |
   |     v              v         |  |     v         v           v     |
   | ---------------------------- |  | ------------------------------- |
   |      2001:DB8:10:2::/64      |  |       2001:DB8:20:2::/64        |
   +------------------------------+  +---------------------------------+
      Vehicle1 (Moving Network1)            EN1 (Fixed Network1)

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

         Figure 2: Internetworking between Vehicle and Edge Network

   As shown in [DMM-FPC], which is Figure 2, as internal networks, a vehicle's moving
   network and an EN's fixed network are self-contained networks having
   multiple subnets and having an edge router (e.g., IP-OBU and IP-RSU)
   for the communication with another vehicle or another EN.  The
   internetworking between two internal networks via V2I communication
   requires the exchange of the network parameters and the network
   prefixes of the internal networks.  For the efficiency, the network
   prefixes of the internal networks (as a moving network) in a vehicle
   need to be delegated and configured automatically.  Note that a
   moving network's network prefix can be called a Mobile Network Prefix
   (MNP) [RFC3963].

   Figure 2 also shows the internetworking between the vehicle's moving
   network and the EN's fixed network.  There exists an internal network
   (Moving Network1) inside Vehicle1.  Vehicle1 has two hosts (Host1 and
   Host2), and two routers (IP-OBU1 and Router1).  There exists another
   internal network (Fixed Network1) inside EN1.  EN1 has one host
   (Host3), two routers (IP-RSU1 and Router2), and the collection of
   servers (Server1 to ServerN) for various services in the road
   networks, such as the emergency notification and navigation.
   Vehicle1's IP-OBU1 (as a mobile router) and EN1's IP-RSU1 (as a fixed
   router) use 2001:DB8:1:1::/64 for an external link (e.g., DSRC) for
   V2I networking.  Thus, a host (Host1) in Vehicle1 can communicate
   with a server (Server1) in EN1 for a vehicular service through
   Vehicle1's moving network, a wireless link between IP-OBU1 and IP-
   RSU1, and EN1's fixed network.

   For the IPv6 communication between an IP-OBU and an IP-RSU or between
   two neighboring IP-OBUs, they need to know the network parameters,
   which include MAC layer and IPv6 layer information.  The MAC layer
   information includes wireless link layer parameters, transmission
   power level, and the MAC address of an external network interface for
   the internetworking with another IP-OBU or IP-RSU.  The IPv6 layer
   information includes the IPv6 address and network prefix of an
   external network interface for the internetworking with another IP-
   OBU or IP-RSU.

   Through the mutual knowledge of the network parameters of internal
   networks, packets can be transmitted between the vehicle's moving
   network and the EN's fixed network.  Thus, V2I requires an efficient
   protocol for the mutual knowledge of network parameters.

   As shown in Figure 2, the addresses used for IPv6 transmissions over
   the wireless link interfaces for IP-OBU and IP-RSU can be link-local
   IPv6 addresses, ULAs, or global IPv6 addresses.  When global IPv6
   addresses are used, wireless interface configuration and control
   overhead for DAD [RFC4862] and Multicast Listener Discovery (MLD)
   [RFC2710][RFC3810] should be minimized to support V2I and V2X
   communications for vehicles moving fast along roadways.

   Let us consider the upload/download time of a vehicle when it passes
   through the wireless communication coverage of an IP-RSU.  For a
   given typical setting where 1km is the maximum DSRC communication
   range [DSRC] and 100km/h is the speed limit in highway, the dwelling
   time can be calculated to be 72 seconds by dividing the diameter of
   the 2km (i.e., two times of DSRC communication range where an IP-RSU
   is located in the center of the circle of wireless communication) by
   the speed limit of 100km/h (i.e., about 28m/s).  For the 72 seconds,
   a vehicle passing through the coverage of an IP-RSU can upload and
   download data packets to/from the IP-RSU.

4.3.  V2V-based Internetworking

   This section discusses the internetworking between the moving
   networks of two neighboring vehicles via V2V communication.

                           (*)<..........>(*)
        (2001:DB8:1:1::/64) |              |
   +------------------------------+  +------------------------------+
   |                        v     |  |     v                        |
   | +-------+          +-------+ |  | +-------+          +-------+ |
   | | Host1 |          |IP-OBU1| |  | |IP-OBU2|          | Host3 | |
   | +-------+          +-------+ |  | +-------+          +-------+ |
   |     ^                  ^     |  |     ^                  ^     |
   |     |                  |     |  |     |                  |     |
   |     v                  v     |  |     v                  v     |
   | ---------------------------- |  | ---------------------------- |
   | 2001:DB8:10:1::/64 ^         |  |         ^ 2001:DB8:30:1::/64 |
   |                    |         |  |         |                    |
   |                    v         |  |         v                    |
   | +-------+      +-------+     |  |     +-------+      +-------+ |
   | | Host2 |      |Router1|     |  |     |Router2|      | 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 Vehicles

   Figure 3 shows the internetworking between the moving networks of two
   neighboring vehicles.  There exists an internal network (Moving
   Network1) inside Vehicle1.  Vehicle1 has two hosts (Host1 and Host2),
   and two routers (IP-OBU1 and Router1).  There exists another internal
   network (Moving Network2) inside Vehicle2.  Vehicle2 has two hosts
   (Host3 and Host4), and two routers (IP-OBU2 and Router2).  Vehicle1's
   IP-OBU1 (as a mobile router) and Vehicle2's IP-OBU2 (as a flexible mobility management system, mobile
   router) use 2001:DB8:1:1::/64 for an external link (e.g., DSRC) for
   V2V networking.  Thus, a host (Host1) in Vehicle1 can
   manage the separation of data-plane communicate
   with another host (Host3) in Vehicle2 for a vehicular service through
   Vehicle1's moving network, a wireless link between IP-OBU1 and control-plane IP-
   OBU2, and Vehicle2's moving network.

   As a V2V use case in DMM.  In
   SDN, Section 3.1, Figure 4 shows the control plane and data plane are separated linear network
   topology of platooning vehicles for V2V communications where Vehicle3
   is the efficient
   management of forwarding elements (e.g., switches leading vehicle with a driver, and routers) where
   an SDN controller configures Vehicle2 and Vehicle1 are
   the following vehicles without drivers.

        (*)<..................>(*)<..................>(*)
         |                      |                      |
   +-----------+          +-----------+          +-----------+
   |           |          |           |          |           |
   | +-------+ |          | +-------+ |          | +-------+ |
   | |IP-OBU1| |          | |IP-OBU2| |          | |IP-OBU3| |
   | +-------+ |          | +-------+ |          | +-------+ |
   |     ^     |          |     ^     |          |     ^     |
   |     |     |=====>    |     |     |=====>    |     |     |=====>
   |     v     |          |     v     |          |     v     |
   | +-------+ |          | +-------+ |          | +-------+ |
   | | Host1 | |          | | Host2 | |          | | Host3 | |
   | +-------+ |          | +-------+ |          | +-------+ |
   |           |          |           |          |           |
   +-----------+          +-----------+          +-----------+
      Vehicle1               Vehicle2               Vehicle3

    <----> Wired Link   <....> Wireless Link   ===> Moving Direction
    (*) Antenna

      Figure 4: Multihop Internetworking between Two Vehicle Networks

   As shown in Figure 4, multihop internetworking is feasible among the forwarding elements
   moving networks of three vehicles in a centralized
   way and they perform packet forwarding according to their forwarding
   tables that are configured by the SDN controller.  An MA as an SDN
   controller needs to efficiently configure and monitor its IP-RSUs and
   vehicles for mobility management, location management, and security
   services.

   The mobility information of a GPS receiver mounted same VANET.  For example,
   Host1 in its vehicle
   (e.g., position, speed, and direction) can be used to accommodate
   mobility-aware proactive handover schemes, which Vehicle1 can perform the
   handover of a vehicle according to its mobility and the wireless
   signal strength of a vehicle communicate with Host3 in Vehicle3 via IP-OBU1
   in Vehicle1, IP-OBU2 in Vehicle2, and an IP-RSU IP-OBU3 in Vehicle3 in a proactive way.

   Vehicles can use the TCC as their Home Network having a home agent
   for mobility management
   VANET, as shown in MIPv6 [RFC6275] and PMIPv6 [RFC5213],
   so the TCC (or an MA inside the TCC) maintains the mobility
   information of vehicles for location management.  IP tunneling over figure.

   In this section, the wireless link should be avoided for performance efficiency.
   Also, in vehicular networks, asymmetric links sometimes exist and
   must between two vehicles is assumed to be considered
   stable for single-hop wireless communications communication regardless of the sight
   relationship such as V2V and V2I.

4.2.  V2I-based Internetworking

   This section discusses the internetworking between a vehicle's
   internal network (i.e., moving network) and an EN's internal network
   (i.e., fixed network) via V2I communication.  The internal network line of
   a vehicle is nowadays constructed with Ethernet by many automotive
   vendors [In-Car-Network].  Note that an EN can accommodate multiple
   routers (or switches) sight and servers (e.g., ECDs, navigation server, and
   DNS server) non-line of sight, as shown in its internal network.

   A vehicle's internal network often uses Ethernet to interconnect
   Electronic Control Units (ECUs)
   Figure 3.  Even in Figure 4, the vehicle.  The internal network
   can support Wi-Fi and Bluetooth three vehicles are connected to accommodate a driver's and
   passenger's mobile devices (e.g., smartphone or tablet).  The network
   topology and subnetting depend on each vendor's network configuration
   for
   other with a vehicle and an EN.  It is reasonable to consider the
   interaction between the internal network and an external linear topology, however, multihop V2V communication can
   accommodate any network
   within another vehicle or topology (i.e., an EN.

                                                    +-----------------+
                           (*)<........>(*)  +----->| Vehicular Cloud arbitrary graph) over
   VANET routing protocols.

        (*)<..................>(*)<..................>(*)
         |
        (2001:DB8:1:1::/64)                      |                      |
   +-----------+          +-----------+          +-----------+
   |           |      +-----------------+
   +------------------------------+  +---------------------------------+          |                        v           |          |   v   v           |
   | +-------+ +-------+ |          | +-------+          +-------+ |          | +-------+ | Host1
   | |IP-OBU1| |          | |IP-RSU1| | Host3          | |IP-OBU3| |
   | +-------+          +-------+ |          | +-------+          +-------+ |          |     ^                  ^ +-------+ |
   |     ^                  ^        |
   |     |          |     |  |     |                  |        |
   |     v                  v     |  |     v                  v        |
   | ---------------------------- |  | ------------------------------- |
   | 2001:DB8:10:1::/64     ^     |          |     ^ 2001:DB8:20:1::/64     |
   |     |     |=====>    |     |     |          |     |     |=====>
   |     v     |          |     v     |          | +-------+      +-------+     v     |
   | +-------+ +-------+   +-------+ |
   | | Host2 |      |Router1|     |  | |Router2| |Server1|...|ServerN| |          | +-------+      +-------+ |          | +-------+ +-------+   +-------+ | |     ^              ^
   | |     ^         ^           ^ Host1 | |          | | Host2 | |          | | Host3 | |
   |     v              v +-------+ |          |     v         v           v +-------+ |          | ---------------------------- +-------+ |
   | -------------------------------           |          |      2001:DB8:10:2::/64           |          |       2001:DB8:20:2::/64           |
   +------------------------------+  +---------------------------------+
   +-----------+          +-----------+          +-----------+
      Vehicle1                 EN1                  Vehicle3

    <----> Wired Link   <....> Wireless Link   ===> Moving Direction
    (*) Antenna

      Figure 5: Multihop Internetworking between Two Vehicle Networks
                             via IP-RSU (V2I2V)

   As shown in Figure 5, multihop internetworking between two vehicles
   is feasible via an infrastructure node (i.e., IP-RSU) with wireless
   connectivity among the moving networks of two vehicles and the fixed
   network of an edge network (denoted as EN1) in the same VANET.  For
   example, Host1 in Vehicle1 (Moving Network1)            EN1 (Fixed Network1)

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

        Figure 3: Internetworking between Vehicle can communicate with Host3 in Vehicle3 via
   IP-OBU1 in Vehicle1, IP-RSU1 in EN1, and Edge Network

   As IP-OBU3 in Vehicle3 in the
   VANET, as shown in Figure 3, the figure.

   For the reliability required in V2V networking, the ND optimization
   defined in MANET [RFC6130] [RFC7466] improves the classical IPv6 ND
   in terms of tracking neighbor information with up to two hops and
   introducing several extensible Information Bases, which serves the
   MANET routing protocols such as internal networks, a vehicle's moving
   network the difference versions of Optimized
   Link State Routing Protocol (OLSR) [RFC3626] [RFC7181] [RFC7188]
   [RFC7722] [RFC7779] [RFC8218] and an EN's fixed the Dynamic Link Exchange Protocol
   (DLEP) with its extensions [RFC8175] [RFC8629] [RFC8651] [RFC8703]
   [RFC8757].  In short, the MANET ND mainly deals with maintaining
   extended network are self-contained neighbors.  However, an ND protocol in vehicular
   networks having
   multiple subnets shall consider more about the geographical mobility
   information of vehicles as an important resource for serving various
   purposes to improve the reliability, e.g., vehicle driving safety,
   intelligent transportation implementations, and advanced mobility
   services.  For a more reliable V2V networking, some redundancy
   mechanisms should be provided in L3 in the case of the failure of L2.

5.  Problem Statement

   In order to specify protocols using the architecture mentioned in
   Section 4.1, IPv6 core protocols have to be adapted to overcome
   certain challenging aspects of vehicular networking.  Since the
   vehicles are likely to be moving at great speed, protocol exchanges
   need to be completed in a time relatively short compared to the
   lifetime of a link between a vehicle and having an edge router IP-RSU, or between two
   vehicles.

   For safe driving, vehicles need to exchange application messages
   every 0.5 second [NHTSA-ACAS-Report] to let drivers take an action to
   avoid a dangerous situation (e.g., IP-OBU and IP-RSU) vehicle collision), so IPv6
   protocol exchanges need to support this order of magnitude for
   application message exchanges.  Also, considering the communication with another vehicle or another EN.  The
   internetworking between two internal networks via V2I communication
   requires the exchange
   range of the network parameters DSRC (up to 1km) and 100km/h as the network
   prefixes of the internal networks.  For the efficiency, speed limit in highway,
   the network
   prefixes lifetime of the internal networks (as a moving network) in link between a vehicle
   need to be delegated and configured automatically. an IP-RSU is 72 seconds,
   and the lifetime of a link between two vehicles is 36 seconds.  Note
   that a if two vehicles are moving network's network prefix can be called in the opposite directions in a Mobile Network Prefix
   (MNP) [OMNI].

   Figure 3 also shows
   roadway, the internetworking relative speed of this case is two times the relative
   speed of a vehicle passing through an RSU.  This relative speed leads
   the half of the link lifetime between the vehicle's moving
   network vehicle and the EN's fixed network.  There exists an internal network
   (Moving Network1) inside Vehicle1.  Vehicle1 has two hosts (Host1 and
   Host2), and two routers (IP-OBU1 and Router1).  There exists another
   internal network (Fixed Network1) inside EN1.  EN1 has one host
   (Host3), IP-RSU.  In
   reality, the DSRC communication range is around 500m, so the link
   lifetime will be a half of the maximum time.  The time constraint of
   a wireless link between two routers (IP-RSU1 and Router2), nodes (e.g., vehicle and IP-RSU) needs to
   be considered because it may affect the collection lifetime of
   servers (Server1 to ServerN) for various services in a session
   involving the road
   networks, link.  The lifetime of a session varies depending on
   the session's type such as the emergency notification and navigation.
   Vehicle1's IP-OBU1 (as a mobile router) web surfing, voice call over IP, DNS
   query, and EN1's IP-RSU1 (as context-aware navigation (in Section 3.1).  Regardless of
   a fixed
   router) use 2001:DB8:1:1::/64 session's type, to guide all the IPv6 packets to their destination
   host(s), IP mobility should be supported for an external link the session.  In a V2V
   scenario (e.g., DSRC) for
   V2I networking.  Thus, context-aware navigation), the IPv6 packets of a host (Host1)
   vehicle should be delivered to relevant vehicles in Vehicle1 can communicate
   with a server (Server1) an efficient way
   (e.g., multicasting).  With this observation, IPv6 protocol exchanges
   need to be done as short as possible to support the message exchanges
   of various applications in EN1 for a vehicular service through
   Vehicle1's moving network, networks.

   Therefore, the time constraint of a wireless link between IP-OBU1 and IP-
   RSU1, and EN1's fixed network.

   For the has a major impact
   on IPv6 communication between an IP-OBU and an IP-RSU or between
   two neighboring IP-OBUs, they need Neighbor Discovery (ND).  Mobility Management (MM) is also
   vulnerable to know disconnections that occur before the network parameters,
   which include MAC layer completion of
   identity verification and IPv6 layer information.  The MAC layer
   information includes tunnel management.  This is especially true
   given the unreliable nature of wireless communication.  Meanwhile,
   the bandwidth of the wireless link layer parameters, determined by the lower layers
   (i.e., link and PHY layers) can affect the transmission
   power level, time of
   control messages of the upper layers (e.g., IPv6) and the MAC address continuity
   of an external network interface for sessions in the internetworking with another IP-OBU or IP-RSU.  The IPv6 layer
   information includes higher layers (e.g., IPv6, TCP, and UDP).  Hence
   the IPv6 address bandwidth selection according to Modulation and Coding Scheme
   (MCS) also affects the vehicular network prefix of an
   external network interface for connectivity.  Note that
   usually the internetworking with another IP-
   OBU or IP-RSU.

   Through higher bandwidth gives the mutual knowledge of shorter communication range
   and the network parameters higher packet error rate at the receiving side, which may
   reduce the reliability of control message exchanges of internal
   networks, packets can be transmitted between the vehicle's moving
   network higher
   layers (e.g., IPv6).  This section presents key topics such as
   neighbor discovery and mobility management for links and sessions in
   IPv6-based vehicular networks.

5.1.  Neighbor Discovery

   IPv6 ND [RFC4861][RFC4862] is a core part of the EN's fixed network.  Thus, V2I requires an efficient IPv6 protocol suite.
   IPv6 ND is designed for link types including point-to-point,
   multicast-capable (e.g., Ethernet) and Non-Broadcast Multiple Access
   (NBMA).  It assumes the mutual knowledge efficient and reliable support of network parameters.

   As shown in Figure 3, the addresses used for IPv6 transmissions over multicast
   and unicast from the wireless link interfaces layer for IP-OBU various network operations such
   as MAC Address Resolution (AR), DAD, MLD and IP-RSU Neighbor Unreachability
   Detection (NUD).

   Vehicles move quickly within the communication coverage of any
   particular vehicle or IP-RSU.  Before the vehicles can exchange
   application messages with each other, they need to be either
   global configured with
   a link-local IPv6 addresses, address or a global IPv6 ULAs as long as address, and run IPv6 packets can be
   routed within ND.

   The requirements for IPv6 ND for vehicular networks [OMNI].  When global IPv6 addresses are used, wireless interface configuration and control overhead for
   Duplicate Address Detection (DAD) [RFC4862] efficient DAD
   and Multicast Listener
   Discovery (MLD) [RFC2710][RFC3810] should be minimized NUD operations.  An efficient DAD is required to support V2I
   and V2X communications for vehicles moving fast along roadways; when
   ULAs and reduce the
   overhead of the DAD packets during a vehicle's travel in a road
   network, which can guarantee the OMNI interface are used, no DAD nor MLD messaging uniqueness of a vehicle's global
   IPv6 address.  An efficient NUD is
   needed.

   Let us consider required to reduce the upload/download time overhead of
   the NUD packets during a vehicle when it passes
   through vehicle's travel in a road network, which
   can guarantee the wireless communication coverage accurate neighborhood information of an IP-RSU.  For a
   given typical setting where 1km is the maximum DSRC communication
   range [DSRC] vehicle in
   terms of adjacent vehicles and 100km/h is RSUs.

   The legacy DAD assumes that a node with an IPv6 address can reach any
   other node with the speed limit in highway, scope of its address at the dwelling time it claims its
   address, and can be calculated to be 72 seconds hear any future claim for that address by dividing another
   party within the diameter scope of its address for the 2km (i.e., two times duration of DSRC communication range where the address
   ownership.  However, the partitioning and merging of VANETs makes
   this assumption frequently invalid in vehicular networks.  The
   merging and partitioning of VANETs frequently occurs in vehicular
   networks.  This merging and partitioning should be considered for the
   IPv6 ND such as IPv6 Stateless Address Autoconfiguration (SLAAC)
   [RFC4862].  Due to the merging of VANETs, two IPv6 addresses may
   conflict with each other though they were unique before the merging.
   An address lookup operation may be conducted by an MA or IP-RSU
   is located (as
   Registrar in RPL) to check the center uniqueness of an IPv6 address that
   will be configured by a vehicle as DAD.  Also, the circle partitioning of wireless communication) a
   VANET may make vehicles with the same prefix be physically
   unreachable.  An address lookup operation may be conducted by an MA
   or IP-RSU (as Registrar in RPL) to check the speed limit existence of 100km/h (i.e., about 28m/s).  For the 72 seconds, a vehicle passing through
   under the network coverage of an IP-RSU can upload and
   download data packets to/from the IP-RSU.

4.3.  V2V-based Internetworking

   This section discusses the internetworking between MA or IP-RSU as NUD.  Thus, SLAAC
   needs to prevent IPv6 address duplication due to the moving
   networks merging of two
   VANETs, and IPv6 ND needs to detect unreachable neighboring vehicles via V2V communication.

                           (*)<..........>(*)
        (2001:DB8:1:1::/64) |              |
   +------------------------------+  +------------------------------+
   |                        v     |  |     v                        |
   | +-------+          +-------+ |  | +-------+          +-------+ |
   | | Host1 |          |IP-OBU1| |  | |IP-OBU2|          | Host3 | |
   | +-------+          +-------+ |  | +-------+          +-------+ |
   |     ^                  ^     |  |     ^                  ^     |
   |     |                  |     |  |     |                  |     |
   |     v                  v     |  |     v                  v     |
   | ---------------------------- |  | ---------------------------- |
   | 2001:DB8:10:1::/64 ^         |  |         ^ 2001:DB8:30:1::/64 |
   |                    |         |  |         |                    |
   |                    v         |  |         v                    |
   | +-------+      +-------+     |  |     +-------+      +-------+ |
   | | Host2 |      |Router1|     |  |     |Router2|      | 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 4: Internetworking between Two Vehicles

   Figure 4 shows the internetworking between vehicles
   due to the moving networks partitioning of two
   neighboring vehicles.  There exists an internal network (Moving
   Network1) inside Vehicle1.  Vehicle1 has two hosts (Host1 a VANET.  According to the merging and Host2),
   partitioning, a destination vehicle (as an IPv6 host) needs to be
   distinguished as either an on-link host or an off-link host even
   though the source vehicle can use the same prefix as the destination
   vehicle [ID-IPPL].

   To efficiently prevent IPv6 address duplication due to the VANET
   partitioning and merging from happening in vehicular networks, the
   vehicular networks need to support a vehicular-network-wide DAD by
   defining a scope that is compatible with the legacy DAD.  In this
   case, two routers (IP-OBU1 and Router1).  There vehicles can communicate with each other when there exists another internal
   a communication path over VANET or a combination of VANETs and IP-
   RSUs, as shown in Figure 1.  By using the vehicular-network-wide DAD,
   vehicles can assure that their IPv6 addresses are unique in the
   vehicular network (Moving Network2) inside Vehicle2.  Vehicle2 has two hosts
   (Host3 whenever they are connected to the vehicular
   infrastructure or become disconnected from it in the form of VANET.

   For vehicular networks with high mobility and Host4), density, the DAD needs
   to be performed efficiently with minimum overhead so that the
   vehicles can exchange driving safety messages (e.g., collision
   avoidance and two routers (IP-OBU2 accident notification) with each other with a short
   interval suggested by NHTSA (National Highway Traffic Safety
   Administration) [NHTSA-ACAS-Report].  Since the partitioning and Router2).  Vehicle1's
   IP-OBU1 (as
   merging of vehicular networks may require re-perform the DAD process
   repeatedly, the link scope of vehicles may be limited to a mobile router) and Vehicle2's IP-OBU2 (as small
   area, which may delay the exchange of driving safety messages.
   Driving safety messages can include a mobile
   router) use 2001:DB8:1:1::/64 vehicle's mobility information
   (i.e., position, speed, direction, and acceleration/deceleration)
   that is critical to other vehicles.  The exchange interval of this
   message is recommended to be less than 0.5 second, which is required
   for a driver to avoid an external link (e.g., DSRC) emergency situation, such as a rear-end
   crash.

   ND time-related parameters such as router lifetime and Neighbor
   Advertisement (NA) interval need to be adjusted for
   V2V networking.  Alternatively, Vehicle1 vehicle speed and Vehicle2 employ
   vehicle density.  For example, the NA interval needs to be
   dynamically adjusted according to a vehicle's speed so that the
   vehicle can maintain its neighboring vehicles in a stable way,
   considering the collision probability with the NA messages sent by
   other vehicles.  The ND time-related parameters can be an OMNI
   interface operational
   setting or an optimization point particularly for vehicular networks.

   For IPv6-based safety applications (e.g., context-aware navigation,
   adaptive cruise control, and use platooning) in vehicular networks, the
   delay-bounded data delivery is critical.  IPv6 ULAs for V2V networking.  Thus, a host (Host1) ND needs to work to
   support those IPv6-based safety applications efficiently.

   From the interoperability point of view, in Vehicle1 can communicate IPv6-based vehicular
   networking, IPv6 ND should have minimum changes with another host (Host3) the legacy IPv6
   ND used in Vehicle2 the Internet, including the DAD and NUD operations, so
   that IPv6-based vehicular networks can be seamlessly connected to
   other intelligent transportation elements (e.g., traffic signals,
   pedestrian wearable devices, electric scooters, and bus stops) that
   use the standard IPv6 network settings.

5.1.1.  Link Model

   A subnet model for a vehicular service through Vehicle1's moving network, a wireless
   link network needs to facilitate the
   communication between two vehicles with the same prefix regardless of
   the vehicular network topology as long as there exist bidirectional
   E2E paths between IP-OBU1 and IP-OBU2, and Vehicle2's moving network.

   As a V2V use case them in Section 3.1, Figure 5 shows the linear vehicular network
   topology of platooning including VANETs and
   IP-RSUs.  This subnet model allows vehicles for V2V communications where Vehicle3
   is with the leading vehicle same prefix to
   communicate with each other via a driver, combination of multihop V2V and Vehicle2
   multihop V2I with VANETs and Vehicle1 are IP-RSUs.  [IPoWIRELESS] introduces other
   issues in an IPv6 subnet model.

   IPv6 protocols work under certain assumptions that do not necessarily
   hold for vehicular wireless access link types [VIP-WAVE][RFC5889].
   For instance, some IPv6 protocols assume symmetry in the following vehicles without drivers.

        (*)<..................>(*)<..................>(*)
         |                      |                      |
   +-----------+          +-----------+          +-----------+
   |           |          |           |          |           |
   | +-------+ |          | +-------+ |          | +-------+ |
   | |IP-OBU1| |          | |IP-OBU2| |          | |IP-OBU3| |
   | +-------+ |          | +-------+ |          | +-------+ |
   |     ^     |          |     ^     |          |     ^     |
   |     |     |=====>    |     |     |=====>    |     |     |=====>
   |     v     |          |     v     |          |     v     |
   | +-------+ |          | +-------+ |          | +-------+ |
   | | Host1 | |          | | Host2 | |          | | Host3 | |
   | +-------+ |          | +-------+ |          | +-------+ |
   |           |          |           |          |           |
   +-----------+          +-----------+          +-----------+
      Vehicle1               Vehicle2               Vehicle3

    <----> Wired Link   <....> Wireless Link   ===> Moving Direction
    (*) Antenna

      Figure 5: Multihop Internetworking between Two Vehicle Networks

   As shown connectivity
   among neighboring interfaces [RFC6250].  However, radio interference
   and different levels of transmission power may cause asymmetric links
   to appear in Figure 5, multihop internetworking vehicular wireless links.  As a result, a new vehicular
   link model needs to consider the asymmetry of dynamically changing
   vehicular wireless links.

   There is feasible among a relationship between a link and a prefix, besides the
   moving networks
   different scopes that are expected from the link-local and global
   types of three vehicles in IPv6 addresses.  In an IPv6 link, it is defined that all
   interfaces which are configured with the same VANET.  For example,
   Host1 in Vehicle1 subnet prefix and with
   on-link bit set can communicate with Host3 in Vehicle3 via IP-OBU1
   in Vehicle1, IP-OBU2 in Vehicle2, each other on an IPv6 link.
   However, the vehicular link model needs to define the relationship
   between a link and IP-OBU3 in Vehicle3 in a prefix, considering the
   linear network, dynamics of wireless
   links and the characteristics of VANET.

   A VANET can have a single link between each vehicle pair within
   wireless communication range, as shown in the figure.

5.  Problem Statement

   In order Figure 4.  When two
   vehicles belong to specify protocols using the architecture mentioned in
   Section 4.1, same VANET, but they are out of wireless
   communication range, they cannot communicate directly with each
   other.  Suppose that a global-scope IPv6 core protocols have to be adapted prefix (or an IPv6 ULA
   prefix) is assigned to overcome
   certain challenging aspects VANETs in vehicular networks.  Even though two
   vehicles in the same VANET configure their IPv6 addresses with the
   same IPv6 prefix, they may not communicate with each other not in one
   hop in the same VANET because of vehicular networking.  Since the
   vehicles are likely to be moving at great speed, protocol exchanges
   need to be completed multihop network connectivity
   between them.  Thus, in a time relatively short compared to this case, the
   lifetime concept of a link between a vehicle and an IP-RSU, or between on-link IPv6
   prefix does not hold because two
   vehicles.

   Note that if vehicles with the same on-link IPv6
   prefix cannot communicate directly with each other.  Also, when two
   vehicles are moving located in two different VANETs with the opposite directions same IPv6
   prefix, they cannot communicate with each other.  When these two
   VANETs converge to one VANET, the two vehicles can communicate with
   each other in a
   roadway, multihop fashion, for example, when they are Vehicle1
   and Vehicle3, as shown in Figure 4.

   From the relative speed of this case is two times previous observation, a vehicular link model should consider
   the relative
   speed frequent partitioning and merging of a VANETs due to vehicle passing through an RSU.  The time constraint of a
   wireless
   mobility.  Therefore, the vehicular link between two nodes model needs to be considered because it may
   affect the lifetime of a session involving use an on-
   link prefix and off-link prefix according to the link.

   The lifetime network topology of a session varies depending on the session's type
   vehicles such as a web surfing, voice call over IP, one-hop reachable network and DNS query.  Regardless of a
   session's type, to guide all multihop reachable
   network (or partitioned networks).  If the vehicles with the same
   prefix are reachable from each other in one hop, the prefix should be
   on-link.  On the other hand, if some of the vehicles with the IPv6 packets same
   prefix are not reachable from each other in one hop due to their destination
   host, IP mobility either the
   multihop topology in the VANET or multiple partitions, the prefix
   should be supported for off-link.  In most cases in vehicular networks, due to the session.

   Thus,
   partitioning and merging of VANETs, and the time constraint multihop network topology
   of a wireless VANETS, off-link prefixes will be used for vehicles as default.

   The vehicular link has model needs to support multihop routing in a major impact on
   connected VANET where the vehicles with the same global-scope IPv6 Neighbor Discovery (ND).  Mobility Management (MM) is
   prefix (or the same IPv6 ULA prefix) are connected in one hop or
   multiple hops.  It also
   vulnerable needs to disconnections that occur before support the completion of
   identity verification and tunnel management.  This is especially true
   given multihop routing in
   multiple connected VANETs through infrastructure nodes (e.g., IP-RSU)
   where they are connected to the unreliable nature of wireless communication.  This section
   presents key topics such as neighbor discovery infrastructure.  For example, in
   Figure 1, suppose that Vehicle1, Vehicle2, and mobility
   management.

5.1.  Neighbor Discovery Vehicle3 are
   configured with their IPv6 ND [RFC4861][RFC4862] is a core part of addresses based on the same global-scope
   IPv6 protocol suite.
   IPv6 ND is designed for link types including point-to-point,
   multicast-capable (e.g., Ethernet) prefix.  Vehicle1 and Non-Broadcast Multiple Access
   (NBMA).  It assumes Vehicle3 can also communicate with each
   other via either multihop V2V or multihop V2I2V.  When Vehicle1 and
   Vehicle3 are connected in a VANET, it will be more efficient for them
   to communicate with each other directly via VANET rather than
   indirectly via IP-RSUs.  On the efficient and reliable support of multicast other hand, when Vehicle1 and unicast
   Vehicle3 are far away from the link layer for various network operations such
   as MAC Address Resolution (AR), DAD, MLD direct communication range in separate
   VANETs and Neighbor Unreachability
   Detection (NUD).

   Vehicles move quickly within under two different IP-RSUs, they can communicate with
   each other through the communication coverage relay of any
   particular vehicle or IP-RSU.  Before the IP-RSUs via V2I2V.  Thus, two
   separate VANETs can merge into one network via IP-RSU(s).  Also,
   newly arriving vehicles can exchange
   application messages with each other, merge two separate VANETs into one VANET
   if they need to be configured with
   a link-local IPv6 address or can play the role of a global IPv6 address, and run IPv6 ND.

   The requirements for IPv6 ND relay node for those VANETs.

   Thus, in IPv6-based vehicular networks are networking, the vehicular link model
   should have minimum changes for interoperability with standard IPv6
   links in an efficient DAD fashion to support IPv6 DAD, MLD and NUD
   operations.  An efficient DAD is required to reduce

5.1.2.  MAC Address Pseudonym

   For the
   overhead protection of the DAD packets during drivers' privacy, a vehicle's travel in pseudonym of a road
   network, which guaranteeing the uniqueness MAC address
   of a vehicle's global IPv6
   address.  An efficient NUD is required to reduce network interface should be used, so that the overhead MAC
   address can be changed periodically.  However, although such a
   pseudonym of the
   NUD packets during a vehicle's travel in MAC address can protect to some extent the privacy of
   a road network, which
   guaranteeing vehicle, it may not be able to resist attacks on vehicle
   identification by other fingerprint information, for example, the accurate neighborhood information of a vehicle
   scrambler seed embedded in
   terms of adjacent vehicles and RSUs. IEEE 802.11-OCB frames [Scrambler-Attack].
   The legacy DAD assumes that pseudonym of a node with MAC address affects an IPv6 address can reach any
   other node with based on the scope of its
   MAC address, and a transport-layer (e.g., TCP and SCTP) session with
   an IPv6 address at pair.  However, the time it claims its
   address, pseudonym handling is not
   implemented and can hear any future claim tested yet for that address by another
   party within applications on IP-based vehicular
   networking.

   In the scope of its address ETSI standards, for the duration 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
   ownership.  However, based on the partitioning network interface identifier
   needs to be updated, and merging the uniqueness of VANETs makes
   this assumption frequently invalid the address needs to be
   checked through the DAD procedure.

5.1.3.  Routing

   For multihop V2V communications in either a VANET or VANETs via IP-
   RSUs, a vehicular networks.  The
   merging Mobile Ad Hoc Networks (MANET) routing protocol may
   be required to support both unicast and partitioning of VANETs frequently occurs multicast in the links of the
   subnet with the same IPv6 prefix.  However, it will be costly to run
   both vehicular
   networks.  This merging ND and partitioning should be considered a vehicular ad hoc routing protocol in terms of
   control traffic overhead [ID-Multicast-Problems].

   A routing protocol for a VANET may cause redundant wireless frames in
   the
   IPv6 ND such as IPv6 Stateless Address Autoconfiguration (SLAAC)
   [RFC4862].  Due air to check the merging neighborhood of VANETs, two IPv6 addresses may
   conflict with each other though they were unique before the merging.

   Also, vehicle and compute the partitioning of
   routing information in a VANET may make vehicles with a dynamic network topology
   because the same
   prefix be physically unreachable.  Also, SLAAC needs to prevent IPv6
   address duplication due ND is used to check the merging neighborhood of VANETs.  According to each
   vehicle.  Thus, the
   merging and partitioning, a destination vehicle (as an IPv6 host) vehicular routing needs to be distinguished as either an on-link host or an off-link
   host even though the source vehicle uses the same prefix as take advantage of the
   destination vehicle.

   To efficiently prevent
   IPv6 address duplication due ND to the VANET
   partitioning minimize its control overhead.

   RPL [RFC6550] defines a routing protocol for low-power and merging from happening in vehicular lossy
   networks, the
   vehicular networks need to support a vehicular-network-wide DAD which constructs and maintains DODAGs optimized by
   defining a scope that is compatible with the legacy DAD.  In this
   case, two vehicles can communicate with each other when there exists an
   Objective Function (OF).  A defined OF provides route selection and
   optimization within a communication path over VANET or RPL topology.  A node in a combination of VANETs DODAG uses DODAG
   Information Objects (DIOs) messages to discover and IP-
   RSUs, as shown in Figure 1.  By using the vehicular-network-wide DAD,
   vehicles can assure that their IPv6 addresses are unique in maintain the
   vehicular network whenever they are connected to
   upward routes toward the vehicular
   infrastructure or become disconnected from it root node.

   An address registration extension for 6LoWPAN (IPv6 over Low-Power
   Wireless Personal Area Network) in the form of VANET.

   ND time-related parameters such as router lifetime and Neighbor
   Advertisement (NA) interval need to be adjusted [RFC8505] can support light-weight
   mobility for vehicle speed and
   vehicle density.  For example, nodes moving through different parents.  Mainly it
   updates the NA interval needs to be
   dynamically adjusted according Address Registration Option (ARO) of ND defined in
   [RFC6775] to include a vehicle's speed so status field that the
   vehicle can maintain its neighboring vehicles in indicate the movement of
   a stable way,
   considering node and optionally a Transaction ID (TID) field, i.e., a sequence
   number that can be used to determine the collision probability with most recent location of a
   node.

   RPL can use the NA messages sent information provided by
   other vehicles.

   For IPv6-based safety applications (e.g., context-aware navigation,
   adaptive cruise control, and platooning) in vehicular networks, the
   delay-bounded data delivery is critical.  IPv6 ND needs extended ARO defined in
   [RFC8505] to work deal with a certain level of node mobility.  When a leaf
   node moves to
   support those IPv6-based safety applications efficiently.

   Thus, in IPv6-based vehicular networking, IPv6 ND the coverage of another parent node, it should have minimum
   changes for de-
   register its addresses to the interoperability previous parent node and register
   itself with the legacy IPv6 ND a new parent node along with an incremented TID.

   Although RPL can be used in IPv6-based vehicular networks, it is
   primarily designed for lossy networks, which puts energy efficiency
   first.  In addition, the
   Internet, including the DAD topology it considers may not quickly scale
   up and NUD operations.

5.1.1.  Link Model

   A prefix model down for a IPv6-based vehicular network needs to facilitate networks, since the
   communication between two mobility of
   vehicles is much more diverse with a high speed, so it can frequently
   alter a tree-like topology formed by RPL, which may cause network
   fragmentation and merging with more control traffic.

   Moreover, due to bandwidth and energy constraints, RPL does not
   suggest to use a proactive mechanism (e.g., keepalive) to maintain
   accurate routing adjacencies such as Bidirectional Forwarding
   Detection [RFC5881] and MANET Neighborhood Discovery Protocol
   [RFC6130].  As a result, due to the same prefix regardless mobility of vehicles, the vehicular network topology as long as there exist bidirectional
   E2E paths between them in
   fragmentation is not detected quickly and the vehicular network routing of packets
   between vehicles or between a vehicle and an infrastructure node may
   fail.

5.2.  Mobility Management

   The seamless connectivity and timely data exchange between two end
   points requires efficient mobility management including VANETs location
   management and
   IP-RSUs.  This prefix model allows handover.  Most vehicles are equipped with the same prefix to
   communicate with each other via a combination GPS
   receiver as part of multihop V2V and
   multihop V2I with VANETs and IP-RSUs.  Note that the OMNI interface
   supports an NBMA link model where multihop V2V and V2I communications
   use each mobile node's ULAs without need for any DAD a dedicated navigation system or MLD
   messaging.

   IPv6 protocols work under certain assumptions a corresponding
   smartphone App.  Note that do not necessarily
   hold for vehicular wireless access link types other than OMNI/NBMA
   [VIP-WAVE][RFC5889]; the rest of this section discusses implications
   for those link types that do GPS receiver may not apply when the OMNI/NBMA link model
   is used.  For instance, some IPv6 protocols assume symmetry provide vehicles
   with accurate location information in the
   connectivity among neighboring interfaces [RFC6250].  However, radio
   interference and different levels adverse environments such as a
   building area or a tunnel.  The location precision can be improved
   with assistance of transmission power may cause
   asymmetric links to appear in vehicular wireless links.  As the IP-RSUs or a result, cellular system with a new vehicular link model needs GPS
   receiver for location information.

   With a GPS navigator, efficient mobility management can be performed
   with the help of vehicles periodically reporting their current
   position and trajectory (i.e., navigation path) to consider the asymmetry of
   dynamically changing vehicular wireless links.

   There is a relationship between a link
   infrastructure (having IP-RSUs and a prefix, besides an MA in TCC).  This vehicular
   infrastructure can predict the
   different scopes that are expected future positions of the vehicles from
   their mobility information (i.e., the link-local current position, speed,
   direction, and global
   types of IPv6 addresses.  In an IPv6 link, it is assumed that all
   interfaces which are configured with trajectory) for efficient mobility management (e.g.,
   proactive handover).  For a better proactive handover, link-layer
   parameters, such as the same subnet prefix and with
   on-link bit set signal strength of a link-layer frame (e.g.,
   Received Channel Power Indicator (RCPI) [VIP-WAVE]), can communicate be used to
   determine the moment of a handover between IP-RSUs along with each other on an IPv6 link.
   However,
   mobility information.

   By predicting a vehicle's mobility, the vehicular link model infrastructure
   needs to define the relationship
   between better support IP-RSUs to perform efficient SLAAC, data
   forwarding, horizontal handover (i.e., handover in wireless links
   using a link homogeneous radio technology), and a prefix, considering the dynamics of vertical handover (i.e.,
   handover in wireless links and using heterogeneous radio technologies) in
   advance along with the characteristics movement of VANET.

   A VANET can have a single link between each vehicle pair within
   wireless communication range, the vehicle.

   For example, as shown in Figure 5.  When two
   vehicles belong to 1, when a vehicle (e.g., Vehicle2) is
   moving from the same VANET, but they are out coverage of wireless
   communication range, they cannot communicate directly with each
   other.  Suppose that a global-scope IPv6 prefix (or an IPv6 ULA
   prefix) is assigned IP-RSU (e.g., IP-RSU1) into the
   coverage of another IP-RSU (e.g., IP-RSU2) belonging to VANETs in vehicular networks.  Even though two
   vehicles in a different
   subnet, the same VANET configure their IPv6 addresses with IP-RSUs can proactively support the
   same IPv6 prefix, they may not communicate with each other not in one
   hop in mobility of the same VANET because
   vehicle, while performing the SLAAC, data forwarding, and handover
   for the sake of the multihop network connectivity
   between them.  Thus, vehicle.

   For a mobility management scheme in this case, a domain, where the concept wireless
   subnets of an on-link IPv6
   prefix does not hold because two vehicles with multiple IP-RSUs share the same on-link prefix, an efficient
   vehicular-network-wide DAD is required.  If DHCPv6 is used to assign
   a unique IPv6
   prefix cannot communicate directly with address to each other.  Also, when two
   vehicles are located vehicle in two different VANETs this shared link, the DAD is
   not required.  On the other hand, for a mobility management scheme
   with a unique prefix per mobile node (e.g., PMIPv6 [RFC5213]), DAD is
   not required because the same IPv6
   prefix, they cannot communicate with each other.  When these two
   VANETs converge address of a vehicle's external
   wireless interface is guaranteed to one VANET, the two vehicles can communicate with
   each other in be unique.  There is a multihop fashion, for example, when they are Vehicle1 tradeoff
   between the prefix usage efficiency and Vehicle3, as shown in Figure 5.

   From DAD overhead.  Thus, the previous observation, a IPv6
   address autoconfiguration for vehicular link model should networks needs to consider
   the frequent partitioning and merging of VANETs due
   this tradeoff to vehicle
   mobility.  Therefore, support efficient mobility management.

   Even though the SLAAC with classic ND costs a DAD during mobility
   management, the SLAAC with [RFC8505] does not cost a DAD.  SLAAC for
   vehicular link model networks needs to use an on-
   link prefix and off-link prefix according to consider the network topology minimization of
   vehicles such as a one-hop reachable network and a multihop reachable
   network (or partitioned networks).  If the vehicles cost of
   DAD with the same help of an infrastructure node (e.g., IP-RSU and MA).
   Using an infrastructure prefix are reachable from each other in one hop, over VANET allows direct routability
   to the prefix should be
   on-link. Internet through the multihop V2I toward an IP-RSU.  On the
   other hand, if some of the vehicles with the same
   prefix are a BYOA does not reachable from each other in one hop due allow such direct routability to either the
   multihop topology in the VANET or multiple partitions,
   Internet since the prefix
   should be off-link.

   The vehicular link model needs to support multihop routing BYOA is not topologically correct, that is, not
   routable in a
   connected VANET where the vehicles Internet.  In addition, a vehicle configured with the same global-scope IPv6
   prefix (or the same IPv6 ULA prefix) are connected in one hop or
   multiple hops.  It also a
   BYOA needs to support the multihop routing in
   multiple connected VANETs through infrastructure nodes a tunnel home (e.g., IP-RSU)
   where they are connected to the infrastructure.  For example, in
   Figure 1, suppose that Vehicle1, Vehicle2, Internet,
   and Vehicle3 are
   configured with their IPv6 addresses based on the same global-scope
   IPv6 prefix.  Vehicle1 and Vehicle3 can also communicate with each
   other via either multihop V2V or multihop V2I2V.  When Vehicle1 and
   Vehicle3 are connected in a VANET, it will be more efficient for them vehicle needs to communicate with each other directly via know which neighboring vehicle is reachable
   inside the VANET rather than
   indirectly via IP-RSUs.  On toward the other hand, when Vehicle1 and
   Vehicle3 are far away from direct communication range in separate
   VANETs tunnel home.  There is nonnegligible
   control overhead to set up and under two different IP-RSUs, they can communicate with
   each other through maintain routes to such a tunnel home
   over the relay VANET.

   For the case of IP-RSUs via V2I2V.  Thus, two
   separate VANETs can merge into one network via IP-RSU(s).  Also,
   newly arriving vehicles can merge two separate VANETs into one VANET
   if they a multihomed network, a vehicle can play follow the role of first-
   hop router selection rule described in [RFC8028].  For example, an
   IP-OBU inside a relay node for vehicle may connect to an IP-RSU that has multiple
   routers behind.  In this scenario, because the IP-OBU can have
   multiple prefixes from those VANETs.

   Thus, routers, the default router selection,
   source address selection, and packet redirect process should follow
   the guidelines in IPv6-based vehicular networking, [RFC8028].  That is, the vehicular link model vehicle should have minimum changes select its
   default router for interoperability with standard IPv6
   links each prefix by preferring the router that
   advertised the prefix.

   Vehicles can use the TCC as their Home Network having a home agent
   for mobility management as in an efficient fashion to support IPv6 DAD, MLD MIPv6 [RFC6275] and NUD
   operations.  When PMIPv6 [RFC5213],
   so the OMNI NBMA link model is used, there are no link
   model changes nor DAD/MLD messaging required.

5.1.2.  MAC Address Pseudonym

   For TCC (or an MA inside the protection of drivers' privacy, a pseudonym of a MAC address TCC) maintains the mobility
   information of a vehicle's network interface vehicles for location management.  IP tunneling over
   the wireless link should be used, so that the MAC
   address can avoided for performance efficiency.
   Also, in vehicular networks, asymmetric links sometimes exist and
   must be changed periodically.  However, although considered for wireless communications such a
   pseudonym as V2V and V2I.

   Therefore, for the proactive and seamless IPv6 mobility of a MAC address can protect vehicles,
   the vehicular infrastructure (including IP-RSUs and MA) needs to some extent
   efficiently perform the privacy mobility management of
   a vehicle, it may not be able to resist attacks on vehicle
   identification by other fingerprint information, for example, the
   scrambler seed embedded vehicles with
   their mobility information and link-layer information.  Also, in IEEE 802.11-OCB frames [Scrambler-Attack].
   The pseudonym of a MAC address affects an
   IPv6-based vehicular networking, IPv6 address based on mobility management should have
   minimum changes for the
   MAC address, and a transport-layer (e.g., TCP and SCTP) session interoperability with
   an IPv6 address pair.  However, the pseudonym handling is not
   implemented legacy IPv6
   mobility management schemes such as PMIPv6, DMM, LISP, and tested yet AERO.

6.  Security Considerations

   This section discusses security and privacy for applications on IP-based IPv6-based vehicular
   networking.

   In the ETSI standards, for the sake of security  Security and privacy, an ITS
   station (e.g., vehicle) can use pseudonyms for its network interface
   identities (e.g., MAC address) privacy are paramount in V2I, V2V, and the corresponding IPv6 addresses
   [Identity-Management].  Whenever the network interface identifier
   changes, the IPv6 address based on the network interface identifier
   needs to be updated, V2X
   networking along with neighbor discovery and the uniqueness of the address needs to mobility management.

   Vehicles and infrastructure must be
   checked through the DAD procedure.

   For authenticated in order to
   participate in vehicular networks with high mobility and density, networking.  For the DAD authentication in
   vehicular networks, vehicular cloud needs to be performed efficiently with minimum overhead so that the support a kind of Public
   Key Infrastructure (PKI) in an efficient way.  To provide safe
   interaction between vehicles can exchange or between a driving safety message vehicle and infrastructure,
   only authenticated nodes (i.e., vehicle and infrastructure node) can
   participate in vehicular networks.  Also, in-vehicle devices (e.g., collision
   avoidance
   ECU) and accident notification) with each other with a short
   interval driver/passenger's mobile devices (e.g., 0.5 second) by a technical report from NHTSA
   (National Highway Traffic Safety Administration) [NHTSA-ACAS-Report].
   Such a driving safety message may include a vehicle's mobility
   information (i.e., position, speed, direction, smartphone and acceleration/
   deceleration).  The exchange interval of this message is 0.5 second,
   which is required to allow
   tablet PC) in a driver vehicle need to avoid a rear-end crash from communicate with other in-vehicle
   devices and another vehicle.

5.1.3.  Routing

   For multihop V2V communications driver/passenger's mobile devices in either a VANET another
   vehicle, or VANETs via IP-
   RSUs, other servers behind an IP-RSU in a vehicular Mobile Ad Hoc Networks (MANET) routing protocol may
   be required to support both unicast secure way.  Even
   though a vehicle is perfectly authenticated and multicast in the links of the
   subnet with the same IPv6 prefix.  However, legitimate, it will may be costly
   hacked for running malicious applications to run
   both vehicular ND track and a vehicular ad hoc routing protocol in terms of
   control traffic overhead [ID-Multicast-Problems].

   A routing protocol for a VANET collect its
   and other vehicles' information.  In this case, an attack mitigation
   process may cause redundant wireless frames in
   the air be required to check reduce the neighborhood aftermath of each vehicle and compute the
   routing information malicious
   behaviors.

   For secure V2I communication, a secure channel (e.g., IPsec) between
   a mobile router (i.e., IP-OBU) in a VANET with vehicle and a dynamic network topology
   because the IPv6 ND is used to check the neighborhood of each
   vehicle.  Thus, the vehicular routing fixed router (i.e.,
   IP-RSU) in an EN needs to take advantage of the
   IPv6 ND to minimize its control overhead.

5.2.  Mobility Management

   The seamless connectivity and timely data exchange be established, as shown in Figure 2
   [RFC4301][RFC4302] [RFC4303][RFC4308] [RFC7296].  Also, for secure
   V2V communication, a secure channel (e.g., IPsec) between two end
   points requires efficient mobility management including location
   management and handover.  Most vehicles are equipped with a GPS
   receiver as part of mobile
   router (i.e., IP-OBU) in a dedicated navigation system or vehicle and a corresponding
   smartphone App.  Note that the GPS receiver may not provide vehicles
   with accurate location information mobile router (i.e., IP-OBU)
   in adverse environments such another vehicle needs to be established, as shown in Figure 3.
   For secure communication, an element in a
   building area or vehicle (e.g., an in-
   vehicle device and a tunnel.  The location precision can be improved driver/passenger's mobile device) needs to
   establish a secure connection (e.g., TLS) with assistance of the IP-RSUs another element in
   another vehicle or another element in a cellular system with vehicular cloud (e.g., a GPS
   receiver
   server).  IEEE 1609.2 [WAVE-1609.2] specifies security services for location information.

   With a GPS navigator, efficient mobility management can be performed
   with the help of vehicles periodically reporting their current
   position and trajectory (i.e., navigation path) to the vehicular
   infrastructure (having IP-RSUs
   applications and an MA in TCC).  This vehicular
   infrastructure can predict management messages, but this WAVE specification is
   optional.  Thus, if the future positions link layer does not support the security of a
   WAVE frame, either the vehicles from
   their mobility information (i.e., network layer or the current position, speed,
   direction, and trajectory) transport layer needs to
   support security services for efficient mobility management (e.g.,
   proactive handover). the WAVE frames.

6.1.  Security Threats in Neighbor Discovery

   For a better proactive handover, link-layer
   parameters, such as the signal strength classical IPv6 ND, the DAD is required to ensure the
   uniqueness of the IPv6 address of a link-layer frame (e.g.,
   Received Channel Power Indicator (RCPI) [VIP-WAVE]), vehicle's wireless interface.
   This DAD can be used to
   determine the moment of a handover between IP-RSUs along with
   mobility information.

   By predicting as a vehicle's mobility, flooding attack that uses the DAD-related
   ND packets disseminated over the VANET or vehicular infrastructure
   needs to better support networks.
   [RFC6959] introduces threats enabled by IP source address spoofing.
   This possibility indicates that vehicles and IP-RSUs need to perform efficient SLAAC, data
   forwarding, horizontal handover (i.e., handover filter
   out suspicious ND traffic in wireless links
   using advance.  [RFC8928] introduces a homogeneous radio technology), and vertical handover (i.e.,
   handover in wireless links using heterogeneous radio technologies) in
   advance along with
   mechanism that protects the movement ownership of the vehicle.

   For example, as shown in Figure 1, when a vehicle (e.g., Vehicle2) is
   moving an address for 6loWPAN ND
   from address theft and impersonation attacks.  Based on the coverage of SEND
   [RFC3971] mechanism, the authentication for routers (i.e., IP-RSUs)
   can be conducted by only selecting an IP-RSU (e.g., IP-RSU1) into that has a certification
   path toward trusted parties.  For authenticating other vehicles, the
   cryptographically generated address (CGA) can be used to verify the
   coverage
   true owner of another IP-RSU (e.g., IP-RSU2) belonging to a different
   subnet, received ND message, which requires to use the IP-RSUs can proactively support CGA ND
   option in the IPv6 mobility ND protocols.  For a general protection of the
   vehicle, while performing ND
   mechanism, the SLAAC, data forwarding, and handover
   for RSA Signature ND option can also be used to protect
   the sake integrity of the vehicle. messages by public key signatures.  For a mobility management scheme in more
   advanced authentication mechanism, a shared link, distributed blockchain-based
   approach [Vehicular-BlockChain] can be used.  However, for a scenario
   where the wireless
   subnets of multiple IP-RSUs share the same prefix, a trustable router or an efficient
   vehicular-network-wide DAD is required.  If DHCPv6 authentication path cannot be
   obtained, it is used desirable to assign find a unique IPv6 address to each vehicle solution in this shared link, the DAD is
   not required.  On the other hand, for a mobility management scheme
   with a unique prefix per mobile node (e.g., PMIPv6 [RFC5213] which vehicles and OMNI
   [OMNI]), DAD is not required because the IPv6 address of a vehicle's
   external wireless interface is guaranteed to be unique.  There is
   infrastructures can authenticate each other without any support from
   a
   tradeoff between the prefix usage efficiency and DAD overhead.  Thus, third party.

   When applying the classical IPv6 address autoconfiguration for vehicular networks needs to
   consider this tradeoff ND process to support efficient mobility management.

   For the case VANET, one of a multihomed network, a vehicle can follow the first-
   hop router selection rule described in [RFC8028].  That is, the
   vehicle should select its default
   security issues is that an IP-RSU (or an IP-OBU) as a router may
   receive deliberate or accidental DoS attacks from network scans that
   probe devices on a VANET.  In this scenario, the IP-RSU can be
   overwhelmed for each prefix by
   preferring processing the router network scan requests so that advertised the prefix.

   Therefore,
   capacity and resources of IP-RSU are exhausted, causing the failure
   of receiving normal ND messages from other hosts for network address
   resolution.  [RFC6583] describes more about the proactive operational problems
   in the classical IPv6 ND mechanism that can be vulnerable to
   deliberate or accidental DoS attacks and seamless suggests several
   implementation guidelines and operational mitigation techniques for
   those problems.  Nevertheless, for running IPv6 mobility of vehicles, ND in VANET, those
   issues can be more acute since the vehicular infrastructure (including IP-RSUs movements of vehicles can be so
   diverse that it leaves a large room for rogue behaviors, and MA) needs to
   efficiently perform the mobility management
   failure of networking among vehicles may cause grave consequences.

   Strong security measures shall protect vehicles roaming in road
   networks from the attacks of malicious nodes, which are controlled by
   hackers.  For safe driving applications (e.g., context-aware
   navigation, cooperative adaptive cruise control, and platooning), as
   explained in Section 3.1, the cooperative action among vehicles with
   their mobility is
   assumed.  Malicious nodes may disseminate wrong driving information
   (e.g., location, speed, and link-layer information.  Also, direction) for disturbing safe driving.
   For example, a Sybil attack, which tries to confuse a vehicle with
   multiple false identities, may disturb a vehicle from taking a safe
   maneuver.

   To identify malicious vehicles among vehicles, an authentication
   method may be required.  A Vehicle Identification Number (VIN) and a
   user certificate (e.g., X.509 certificate [RFC5280]) along with an
   in-vehicle device's identifier generation can be used to efficiently
   authenticate a vehicle or its driver (having a user certificate)
   through a road infrastructure node (e.g., IP-RSU) connected to an
   authentication server in
   IPv6-based the vehicular networking, IPv6 mobility management should have
   minimum changes for cloud.  This authentication
   can be used to identify the interoperability vehicle that will communicate with an
   infrastructure node or another vehicle.  In the legacy IPv6
   mobility management schemes such as PMIPv6, DMM, LISP, case where a vehicle
   has an internal network (called Moving Network) and AERO.

6.  Security Considerations

   This section discusses security elements in the
   network (e.g., in-vehicle devices and privacy a user's mobile devices), as
   shown in Figure 2, the elements in the network need to be
   authenticated individually for IPv6-based vehicular
   networking. safe authentication.  Also, Transport
   Layer Security and privacy are key components of IPv6-based (TLS) certificates [RFC8446][RFC5280] can be used for
   an element's authentication to allow secure E2E vehicular networking along with neighbor discovery and mobility
   management.

   Security and privacy are paramount
   communications between an element in V2I, V2V, and V2X networking.
   Vehicles a vehicle and infrastructure must be authenticated another element in order to
   participate
   a server in vehicular networking.  Also, in-vehicle devices (e.g.,
   ECU) and a driver/passenger's mobile devices (e.g., smartphone and
   tablet PC) vehicular cloud, or between an element in a vehicle need to communicate with other in-vehicle
   devices and
   another driver/passenger's mobile devices element in another
   vehicle, or other servers behind an IP-RSU vehicle.

6.2.  Security Threats in Mobility Management

   For mobility management, a secure way.  Even
   though malicious vehicle can construct multiple
   virtual bogus vehicles, and register them with IP-RSUs and MA.  This
   registration makes the IP-RSUs and MA waste their resources.  The IP-
   RSUs and MA need to determine whether a vehicle is perfectly authenticated genuine or bogus
   in mobility management.  Also, the confidentiality of control packets
   and legitimate, it may be
   hacked for running malicious applications data packets among IP-RSUs and MA, the E2E paths (e.g., tunnels)
   need to track and collect its
   and other vehicles' information.  In this case, an attack mitigation
   process may be required protected by secure communication channels.  In addition,
   to reduce the aftermath of malicious
   behaviors.

   Strong security measures shall protect vehicles roaming in road
   networks prevent bogus IP-RSUs and MA from interfering with the attacks IPv6
   mobility of malicious nodes, which are controlled vehicles, mutual authentication among them needs to be
   performed by
   hackers.  For safe driving applications certificates (e.g., context-aware
   navigation, cooperative adaptive cruise control, and platooning), as
   explained in Section 3.1, TLS certificate).

6.3.  Other Threats

   For the cooperative action among vehicles setup of a secure channel over IPsec or TLS, the multihop V2I
   communications over DSRC or 5G V2X (or LTE V2X) is
   assumed.  Malicious required in a
   highway.  In this case, multiple intermediate vehicles as relay nodes may disseminate wrong driving information
   (e.g., location, speed,
   can help forward association and direction) for disturbing safe driving.
   For example, a Sybil attack, which tries authentication messages toward an
   IP-RSU (gNodeB, or eNodeB) connected to confuse a an authentication server in
   the vehicular cloud.  In this kind of process, the authentication
   messages forwarded by each vehicle with
   multiple false identities, can be delayed or lost, which may disturb a vehicle from taking
   increase the construction time of a safe
   maneuver. connection or some vehicles may
   not be able to be authenticated.

   Even though vehicles can be authenticated with valid certificates by
   an authentication server in the vehicular cloud, the authenticated
   vehicles may harm other vehicles, so their vehicles.  To deal with this kind of security
   issue, for monitoring suspicious behaviors, vehicles' communication
   activities
   need to can be logged recorded in either a central way through a logging
   server (e.g., TCC) in the vehicular cloud or a distributed way (e.g.,
   blockchain [Bitcoin]) along with other vehicles or infrastructure. infrastructure.
   To solve the issue ultimately, we need a solution where, without
   privacy breakage, vehicles may observe activities of each other to
   identify any misbehavior.  Once identifying a misbehavior, a vehicle
   shall have a way to either isolate itself from others or isolate a
   suspicious vehicle by informing other vehicles.  Alternatively, for
   completely secure vehicular networks, we shall embrace the concept of
   "zero-trust" for vehicles in which no vehicle is trustable and
   verifying every message is necessary.  For doing so, we shall have an
   efficient zero-trust framework or mechanism for vehicular networks.

   For the non-repudiation of the harmful activities of malicious nodes,
   a blockchain technology can be used [Bitcoin].  Each message from a
   vehicle can be treated as a transaction and the neighboring vehicles
   can play the role of peers in a consensus method of a blockchain
   [Bitcoin][Vehicular-BlockChain].
   [Bitcoin] [Vehicular-BlockChain].  For a blockchain's efficient
   consensus in vehicular networks having fast moving vehicles, a new
   consensus algorithm needs to be developed or an existing consensus
   algorithm needs to be enhanced.

   To identify malicious vehicles among vehicles, prevent an authentication
   method is required.  A Vehicle Identification Number (VIN) and adversary from tracking a user
   certificate (e.g., X.509 certificate [RFC5280]) along with an in- vehicle device's identifier generation can with its MAC address
   or IPv6 address, especially for a long-living transport-layer session
   (e.g., voice call over IP and video streaming service), a MAC address
   pseudonym needs to be used provided to efficiently
   authenticate a each vehicle; that is, each vehicle or
   periodically updates its driver (having a user certificate)
   through a road infrastructure node (e.g., IP-RSU) connected MAC address and its IPv6 address needs to be
   updated accordingly by the MAC address change [RFC4086][RFC4941].
   Such an
   authentication server in update of the vehicular cloud.  This authentication
   can be used to identify MAC and IPv6 addresses should not interrupt the
   E2E communications between two vehicles (or between a vehicle that will communicate with and an
   infrastructure node
   IP-RSU) for a long-living transport-layer session.  However, if this
   pseudonym is performed without strong E2E confidentiality (using
   either IPsec or another vehicle.  In TLS), there will be no privacy benefit from changing
   MAC and IPv6 addresses, because an adversary can observe the change
   of the MAC and IPv6 addresses and track the vehicle with those
   addresses.  Thus, the MAC address pseudonym and the IPv6 address
   update should be performed with strong E2E confidentiality.

7.  IANA Considerations

   This document does not require any IANA actions.

8.  References

8.1.  Normative References

   [RFC8691]  Benamar, N., Haerri, J., Lee, J., and T. Ernst, "Basic
              Support for IPv6 Networks Operating Outside the case where Context of
              a vehicle
   has an internal network (called Moving Network) Basic Service Set over IEEE Std 802.11", RFC 8691,
              December 2019, <https://www.rfc-editor.org/rfc/rfc8691>.

   [RFC8200]  Deering, S. and elements in the
   network (e.g., in-vehicle devices R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", RFC 8200, July 2017,
              <https://www.rfc-editor.org/rfc/rfc8200>.

   [RFC6275]  Perkins, C., Ed., Johnson, D., and a user's mobile devices), as
   shown in Figure 3, the elements J. Arkko, "Mobility
              Support in the network need to be
   authenticated individually IPv6", RFC 6275, July 2011,
              <https://www.rfc-editor.org/rfc/rfc6275>.

   [RFC5213]  Gundavelli, S., Ed., Leung, K., Devarapalli, V.,
              Chowdhury, K., and B. Patil, "Proxy Mobile IPv6",
              RFC 5213, August 2008,
              <https://www.rfc-editor.org/rfc/rfc5213>.

   [RFC7333]  Chan, H., Liu, D., Seite, P., Yokota, H., and J. Korhonen,
              "Requirements for safe authentication.  Also, Transport
   Layer Security (TLS) certificates [RFC8446][RFC5280] can be used Distributed Mobility Management",
              RFC 7333, August 2014,
              <https://www.rfc-editor.org/rfc/rfc7333>.

   [RFC7429]  Liu, D., Zuniga, JC., Seite, P., Chan, H., and CJ.
              Bernardos, "Distributed Mobility Management: Current
              Practices and Gap Analysis", RFC 7429, January 2015,
              <https://www.rfc-editor.org/rfc/rfc7429>.

   [RFC3963]  Devarapalli, V., Wakikawa, R., Petrescu, A., and P.
              Thubert, "Network Mobility (NEMO) Basic Support Protocol",
              RFC 3963, January 2005,
              <https://www.rfc-editor.org/rfc/rfc3963>.

   [RFC6550]  Winter, T., Thubert, P., Brandt, A., Hui, J., Kelsey, R.,
              Levis, P., Pister, K., Struik, R., Vasseur, JP., and R.
              Alexander, "RPL: IPv6 Routing Protocol for
   an element's authentication to allow secure E2E vehicular
   communications between an element in a vehicle Low-Power and
              Lossy Networks", RFC 6550, March 2012,
              <https://www.rfc-editor.org/rfc/rfc6550>.

   [RFC3753]  Manner, J. and M. Kojo, "Mobility Related Terminology",
              RFC 3753, June 2004,
              <https://www.rfc-editor.org/rfc/rfc3753>.

   [RFC5415]  Calhoun, P., Montemurro, M., and D. Stanley, "Control And
              Provisioning of Wireless Access Points (CAPWAP) Protocol
              Specification", RFC 5415, March 2009,
              <https://www.rfc-editor.org/rfc/rfc5415>.

   [RFC7149]  Boucadair, M. and another element in
   a server in a vehicular cloud, or between an element in C. Jacquenet, "Software-Defined
              Networking: A Perspective from within a vehicle Service Provider
              Environment", RFC 7149, March 2014,
              <https://www.rfc-editor.org/rfc/rfc7149>.

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and
   another element in another vehicle.

   For secure V2I communication, a secure channel (e.g., IPsec) between
   a mobile router (i.e., IP-OBU) in a vehicle H. Soliman,
              "Neighbor Discovery for IP Version 6 (IPv6)", RFC 4861,
              September 2007, <https://www.rfc-editor.org/rfc/rfc4861>.

   [RFC4862]  Thomson, S., Narten, T., and a fixed router (i.e.,
   IP-RSU) in an EN needs to be established, as shown in Figure 3
   [RFC4301][RFC4302][RFC4303][RFC4308][RFC7296].  Also, T. Jinmei, "IPv6 Stateless
              Address Autoconfiguration", RFC 4862, September 2007,
              <https://www.rfc-editor.org/rfc/rfc4862>.

   [RFC4193]  Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
              Addresses", RFC 4193, October 2005,
              <https://www.rfc-editor.org/rfc/rfc4193>.

   [RFC2710]  Deering, S., Fenner, W., and B. Haberman, "Multicast
              Listener Discovery (MLD) for secure V2V
   communication, a secure channel (e.g., IPsec) between a mobile router
   (i.e., IP-OBU) in a vehicle IPv6", RFC 2710, October
              1999, <https://www.rfc-editor.org/rfc/rfc2710>.

   [RFC3810]  Vida, R. and a mobile router (i.e., IP-OBU) in
   another vehicle needs to be established, as shown in Figure 4.  For
   secure communication, an element in a vehicle (e.g., an in-vehicle
   device L. Costa, "Multicast Listener Discovery
              Version 2 (MLDv2) for IPv6", RFC 3810, June 2004,
              <https://www.rfc-editor.org/rfc/rfc3810>.

   [RFC5889]  Baccelli, E. and a driver/passenger's mobile device) needs to establish a
   secure connection (e.g., TLS) with another element in another vehicle
   or another element M. Townsley, "IP Addressing Model in a vehicular cloud (e.g., a server).  Even
   though IEEE 1609.2 [WAVE-1609.2] specifies security services Ad
              Hoc Networks", RFC 5889, September 2010,
              <https://www.rfc-editor.org/rfc/rfc5889>.

   [RFC4086]  Eastlake 3rd, D., Schiller, J., and S. Crocker,
              "Randomness Requirements for
   applications Security", RFC 4086, June
              2005, <https://www.rfc-editor.org/rfc/rfc4086>.

   [RFC4941]  Narten, T., Draves, R., and management messages, this WAVE specification is
   optional.  Thus, if WAVE does not support the security of a WAVE
   frame, either the network layer or the transport layer needs to
   support security services S. Krishnan, "Privacy
              Extensions for the WAVE frames.

   For the setup of a secure channel over IPsec or TLS, the multihop V2I
   communications over DSRC is required Stateless Address Autoconfiguration in a highway
              IPv6", RFC 4941, September 2007,
              <https://www.rfc-editor.org/rfc/rfc4941>.

   [RFC3849]  Huston, G., Lord, A., and P. Smith, "IPv6 Address Prefix
              Reserved for Documentation", RFC 3849, July 2004,
              <https://www.rfc-editor.org/rfc/rfc3849>.

   [RFC6250]  Thaler, D., "Evolution of the
   authentication by involving multiple intermediate vehicles as relay
   nodes toward an IP-RSU connected to an authentication server in IP Model", RFC 6250, May
              2011, <https://www.rfc-editor.org/rfc/rfc6250>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, August 2018,
              <https://www.rfc-editor.org/rfc/rfc8446>.

   [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R., and W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 5280, May 2008,
              <https://www.rfc-editor.org/rfc/rfc5280>.

   [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the
   vehicular cloud.  The V2I communications over 5G V2X (or LTE V2X) is
   required to allow a vehicle to communicate directly with a gNodeB (or
   eNodeB) connected to an authentication server
              Internet Protocol", RFC 4301, December 2005,
              <https://www.rfc-editor.org/rfc/rfc4301>.

   [RFC4302]  Kent, S., "IP Authentication Header", RFC 4302, December
              2005, <https://www.rfc-editor.org/rfc/rfc4302>.

   [RFC4303]  Kent, S., "IP Encapsulating Security Payload (ESP)",
              RFC 4303, December 2005,
              <https://www.rfc-editor.org/rfc/rfc4303>.

   [RFC4308]  Hoffman, P., "Cryptographic Suites for IPsec", RFC 4308,
              December 2005, <https://www.rfc-editor.org/rfc/rfc4308>.

   [RFC7296]  Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
              Kivinen, "Internet Key Exchange Protocol Version 2
              (IKEv2)", RFC 7296, October 2014,
              <https://www.rfc-editor.org/rfc/rfc7296>.

   [RFC8028]  Baker, F. and B. Carpenter, "First-Hop Router Selection by
              Hosts in the vehicular cloud.

   To prevent an adversary from tracking a vehicle with its MAC address
   or Multi-Prefix Network", RFC 8028, November 2016,
              <https://www.rfc-editor.org/rfc/rfc8028>.

   [RFC3971]  Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure
              Neighbor Discovery (SEND)", RFC 3971, March 2005,
              <https://www.rfc-editor.org/rfc/rfc3971>.

   [RFC8505]  Thubert, P., Nordmark, E., Chakrabarti, S., and C.
              Perkins, "Registration Extensions for IPv6 address, especially over Low-Power
              Wireless Personal Area Network (6LoWPAN) Neighbor
              Discovery", RFC 8505, November 2018,
              <https://www.rfc-editor.org/rfc/rfc8505>.

   [RFC6775]  Shelby, Z., Chakrabarti, S., Nordmark, E., and C. Bormann,
              "Neighbor Discovery Optimization for a long-living transport-layer session
   (e.g., voice call IPv6 over IP Low-Power
              Wireless Personal Area Networks (6LoWPANs)", RFC 6775,
              November 2012, <https://www.rfc-editor.org/rfc/rfc6775>.

   [RFC5881]  Katz, D. and video streaming service), a MAC address
   pseudonym needs to be provided to each vehicle; that is, each vehicle
   periodically updates its MAC address D. Ward, "Bidirectional Forwarding Detection
              (BFD) for IPv4 and its IPv6 address needs to be
   updated accordingly by the MAC address change [RFC4086][RFC4941].

   Such an update of the MAC (Single Hop)", RFC 5881, June
              2010, <https://www.rfc-editor.org/rfc/rfc5881>.

   [RFC6130]  Clausen, T., Dearlove, C., and IPv6 addresses should not interrupt the
   E2E communications between two vehicles (or between a vehicle J. Dean, "Mobile Ad Hoc
              Network (MANET) Neighborhood Discovery Protocol (NHDP)",
              RFC 6130, April 2011,
              <https://www.rfc-editor.org/rfc/rfc6130>.

   [RFC6583]  Gashinsky, I., Jaeggli, J., and an
   IP-RSU) W. Kumari, "Operational
              Neighbor Discovery Problems", RFC 6583, March 2012,
              <https://www.rfc-editor.org/rfc/rfc6583>.

   [RFC8928]  Thubert, P., Sarikaya, B., Sethi, M., and R. Struik,
              "Address-Protected Neighbor Discovery for a long-living transport-layer session.  However, if this
   pseudonym is performed without strong E2E confidentiality (using
   either IPsec or TLS), there will be no privacy benefit from changing
   MAC Low-Power and IPv6 addresses, because an adversary can observe the change
   of the MAC
              Lossy Networks", RFC 8928, November 2020,
              <https://www.rfc-editor.org/rfc/rfc8928>.

   [RFC3626]  Clausen, T. and P. Jacquet, "Optimized Link State Routing
              Protocol (OLSR)", RFC 3626, October 2003,
              <https://www.rfc-editor.org/rfc/rfc3626>.

   [RFC7181]  Clausen, T., Dearlove, C., Jacquet, P., and U. Herberg,
              "The Optimized Link State Routing Protocol Version 2",
              RFC 7181, April 2014,
              <https://www.rfc-editor.org/rfc/rfc7181>.

   [RFC7188]  Dearlove, C. and IPv6 addresses T. Clausen, "Optimized Link State Routing
              Protocol Version 2 (OLSRv2) and track the vehicle with those
   addresses.  Thus, the MAC address pseudonym MANET Neighborhood
              Discovery Protocol (NHDP) Extension TLVs", RFC 7188, April
              2014, <https://www.rfc-editor.org/rfc/rfc7188>.

   [RFC7722]  Dearlove, C. and T. Clausen, "Multi-Topology Extension for
              the IPv6 address
   update should be performed with strong E2E confidentiality.

   For the IPv6 ND, the DAD is required to ensure the uniqueness of the
   IPv6 address of a vehicle's wireless interface.  This DAD can be used
   as a flooding attack that uses the DAD-related ND packets
   disseminated over the VANET or vehicular networks.  This possibility
   indicates that the vehicles Optimized Link State Routing Protocol Version 2
              (OLSRv2)", RFC 7722, December 2015,
              <https://www.rfc-editor.org/rfc/rfc7722>.

   [RFC7779]  Rogge, H. and IP-RSUs need to filter out suspicious
   ND traffic in advance. E. Baccelli, "Directional Airtime Metric
              Based on the SEND [RFC3971] mechanism, the
   authentication Packet Sequence Numbers for routers (i.e., IP-RSUs) can be conducted by only
   selecting an IP-RSU that has a certification path toward trusted
   parties.  For authenticating other vehicles, the cryptographically
   generated address (CGA) can be used to verify the true owner of a
   received ND message, which requires to use the CGA ND option in the
   ND protocols.  For a general protection of the ND mechanism, the RSA
   Signature ND option can also be used to protect the integrity of the
   messages by public key signatures.  For a more advanced
   authentication mechanism, a distributed blockchain-based mechanism
   [Vehicular-BlockChain] can be used.

   For mobility management, a malicious vehicle can construct multiple
   virtual bogus vehicles, and register them with IP-RSUs Optimized Link State
              Routing Version 2 (OLSRv2)", RFC 7779, April 2016,
              <https://www.rfc-editor.org/rfc/rfc7779>.

   [RFC8218]  Yi, J. and MA.  This
   registration makes B. Parrein, "Multipath Extension for the IP-RSUs
              Optimized Link State Routing Protocol Version 2 (OLSRv2)",
              RFC 8218, August 2017,
              <https://www.rfc-editor.org/rfc/rfc8218>.

   [RFC8175]  Ratliff, S., Jury, S., Satterwhite, D., Taylor, R., and B.
              Berry, "Dynamic Link Exchange Protocol (DLEP)", RFC 8175,
              June 2017, <https://www.rfc-editor.org/rfc/rfc8175>.

   [RFC8629]  Cheng, B. and MA waste their resources.  The IP-
   RSUs L. Berger, "Dynamic Link Exchange Protocol
              (DLEP) Multi-Hop Forwarding Extension", RFC 8629, July
              2019, <https://www.rfc-editor.org/rfc/rfc8629>.

   [RFC8651]  Cheng, B., Wiggins, D., and MA need to determine whether a vehicle is genuine or bogus
   in mobility management.  Also, the confidentiality of control packets L. Berger, "Dynamic Link
              Exchange Protocol (DLEP) Control-Plane-Based Pause
              Extension", RFC 8651, October 2019,
              <https://www.rfc-editor.org/rfc/rfc8651>.

   [RFC8703]  Taylor, R. and data packets among IP-RSUs S. Ratliff, "Dynamic Link Exchange Protocol
              (DLEP) Link Identifier Extension", RFC 8703, February
              2020, <https://www.rfc-editor.org/rfc/rfc8703>.

   [RFC8757]  Cheng, B. and MA, the E2E paths (e.g., tunnels)
   need to be protected by secure communication channels.  In addition,
   to prevent bogus IP-RSUs L. Berger, "Dynamic Link Exchange Protocol
              (DLEP) Latency Range Extension", RFC 8757, March 2020,
              <https://www.rfc-editor.org/rfc/rfc8757>.

   [RFC7466]  Dearlove, C. and MA from interfering with T. Clausen, "An Optimization for the IPv6
   mobility of vehicles, mutual authentication among them needs to be
   performed by certificates (e.g., TLS certificate).

7.  IANA Considerations

   This document does not require any IANA actions.

8.
              Mobile Ad Hoc Network (MANET) Neighborhood Discovery
              Protocol (NHDP)", RFC 7466, March 2015,
              <https://www.rfc-editor.org/rfc/rfc7466>.

8.2.  Informative References

   [Automotive-Sensing]
              Choi, J., Va,

   [ID-IPPL]  Nordmark, E., "IP over Intentionally Partially Partitioned
              Links", Work in Progress, Internet-Draft, draft-ietf-
              intarea-ippl-00, March 2017,
              <https://datatracker.ietf.org/doc/html/draft-ietf-intarea-
              ippl-00>.

   [RFC6830BIS]
              Farinacci, D., Fuller, V., Gonzalez-Prelcic, N., Daniels, R., R.
              Bhat, C., and R. W. Heath, "Millimeter-Wave Vehicular
              Communication to Support Massive Automotive Sensing",
              IEEE Communications Magazine, December 2016.

   [Bitcoin]  Nakamoto, S., "Bitcoin: A Peer-to-Peer Electronic Cash
              System", URL: https://bitcoin.org/bitcoin.pdf, May 2009.

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

   [CASD]     Shen, Y., Jeong, J., Oh, T., Meyer, D., Lewis, D., and S. Son, "CASD: A
              Framework of Context-Awareness Safety Driving A.
              Cabellos, "The Locator/ID Separation Protocol (LISP)",
              Work in Vehicular
              Networks", International Workshop on Device Centric Cloud
              (DC2), March 2016.

   [CBDN]     Kim, J., Kim, S., Jeong, J., Kim, H., Park, J., Progress, Internet-Draft, draft-ietf-lisp-
              rfc6830bis-36, November 2020,
              <https://datatracker.ietf.org/doc/html/draft-ietf-lisp-
              rfc6830bis-36>.

   [RFC6706BIS]
              Templin, F., "Automatic Extended Route Optimization
              (AERO)", Work in Progress, Internet-Draft, draft-templin-
              intarea-6706bis-99, March 2021,
              <https://datatracker.ietf.org/doc/html/draft-templin-
              intarea-6706bis-99>.

   [OMNI]     Templin, F. and T.
              Kim, "CBDN: Cloud-Based Drone Navigation for Efficient
              Battery Charging A. Whyman, "Transmission of IP Packets
              over Overlay Multilink Network (OMNI) Interfaces", Work in Drone Networks", IEEE Transactions on
              Progress, Internet-Draft, draft-templin-6man-omni-41,
              August 2021, <https://datatracker.ietf.org/doc/html/draft-
              templin-6man-omni-41>.

   [UAM-ITS]  Templin, F., "Urban Air Mobility Implications for
              Intelligent Transportation Systems, November 2019. Systems", Work in Progress,
              Internet-Draft, draft-templin-ipwave-uam-its-04, January
              2021, <https://datatracker.ietf.org/doc/html/draft-
              templin-ipwave-uam-its-04>.

   [DMM-FPC]  Matsushima, S., Bertz, L., Liebsch, M., Gundavelli, S.,
              Moses, D., and C. Perkins, "Protocol for Forwarding Policy
              Configuration (FPC) in DMM", draft-ietf-dmm-fpc-cpdp-14
              (work Work in progress), Progress, Internet-
              Draft, draft-ietf-dmm-fpc-cpdp-14, September 2020. 2020,
              <https://datatracker.ietf.org/doc/html/draft-ietf-dmm-fpc-
              cpdp-14>.

   [ID-Multicast-Problems]
              Perkins, C., McBride, M., Stanley, D., Kumari, W., and JC.
              Zuniga, "Multicast Considerations over IEEE 802 Wireless
              Media", Work in Progress, Internet-Draft, draft-ietf-
              mboned-ieee802-mcast-problems-15, July 2021,
              <https://datatracker.ietf.org/doc/html/draft-ietf-mboned-
              ieee802-mcast-problems-15>.

   [DSRC]     ASTM International, "Standard Specification for
              Telecommunications and Information Exchange Between
              Roadside and Vehicle Systems - 5 GHz Band Dedicated Short
              Range Communications (DSRC) Medium Access Control (MAC)
              and Physical Layer (PHY) Specifications",
              ASTM E2213-03(2010), October 2010.

   [EU-2008-671-EC]
              European Union, "Commission Decision of 5 August 2008 on
              the Harmonised Use of Radio Spectrum in the 5875 - 5905
              MHz Frequency Band for Safety-related Applications of
              Intelligent Transport Systems (ITS)", EU 2008/671/EC,
              August 2008.

   [FirstNet]
              U.S. National Telecommunications and Information
              Administration (NTIA), "First Responder Network Authority
              (FirstNet)", 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 D. V. Dimarogonas,
              "Fuel-Efficient En Route Formation of Truck Platoons",
              IEEE Transactions on Intelligent Transportation Systems,
              January 2018.

   [ID-Multicast-Problems]
              Perkins, C., McBride, M., Stanley, D., Kumari, W., and JC.
              Zuniga, "Multicast Considerations over IEEE 802 Wireless
              Media", draft-ietf-mboned-ieee802-mcast-problems-13 (work
              in progress), February 2021.

   [Identity-Management]
              Wetterwald, M., Hrizi, F., and P. Cataldi, "Cross-layer
              Identities Management in ITS Stations", The 10th
              International Conference on ITS Telecommunications,
              November 2010.

   [IEEE-802.11-OCB]

   [IEEE-802.11p]
              "Part 11: Wireless LAN Medium Access Control (MAC) and
              Physical Layer (PHY) Specifications", Specifications - Amendment 6:
              Wireless Access in Vehicular Environments", IEEE Std
              802.11-2016, December 2016.

   [IEEE-802.11p]
              802.11p-2010, June 2010.

   [IEEE-802.11-OCB]
              "Part 11: Wireless LAN Medium Access Control (MAC) and
              Physical Layer (PHY) Specifications Specifications", IEEE Std
              802.11-2016, December 2016.

   [WAVE-1609.0]
              IEEE 1609 Working Group, "IEEE Guide for Wireless Access
              in Vehicular Environments (WAVE) - Amendment 6: Architecture", IEEE Std
              1609.0-2013, March 2014.

   [WAVE-1609.2]
              IEEE 1609 Working Group, "IEEE Standard for Wireless
              Access 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 for Wireless
              Access in Vehicular Environments", Environments (WAVE) - Networking
              Services", IEEE Std
              802.11p-2010, June 2010.

   [In-Car-Network]
              Lim, H., Volker, L., and D. Herrscher, "Challenges in a
              Future IP/Ethernet-based In-Car Network 1609.3-2016, April 2016.

   [WAVE-1609.4]
              IEEE 1609 Working Group, "IEEE Standard for Real-Time
              Applications", ACM/EDAC/IEEE Design Automation Conference
              (DAC), June 2011. Wireless
              Access in Vehicular Environments (WAVE) - Multi-Channel
              Operation", IEEE Std 1609.4-2016, March 2016.

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

   [ISO-ITS-IPv6-AMD1]
              ISO/TC 204, "Intelligent Transport Systems -
              Communications Access for Land Mobiles (CALM) - IPv6
              Networking - Amendment 1", ISO 21210:2012/AMD 1:2017,
              September 2017.

   [NHTSA-ACAS-Report]
              National Highway Traffic Safety Administration (NHTSA),
              "Final Report

   [TS-23.285-3GPP]
              3GPP, "Architecture Enhancements for V2X Services", 3GPP
              TS 23.285/Version 16.2.0, December 2019.

   [TR-22.886-3GPP]
              3GPP, "Study on Enhancement of Automotive Collision Avoidance Systems
              (ACAS) Program", DOT HS 809 080, August 2000.

   [OMNI]     Templin, F. 3GPP Support for 5G V2X
              Services", 3GPP TR 22.886/Version 16.2.0, December 2018.

   [TS-23.287-3GPP]
              3GPP, "Architecture Enhancements for 5G System (5GS) to
              Support Vehicle-to-Everything (V2X) Services", 3GPP
              TS 23.287/Version 16.2.0, March 2020.

   [VIP-WAVE] Cespedes, S., Lu, N., and X. Shen, "VIP-WAVE: On the
              Feasibility of IP Communications in 802.11p Vehicular
              Networks", IEEE Transactions on Intelligent Transportation
              Systems, vol. 14, no. 1, March 2013.

   [Identity-Management]
              Wetterwald, M., Hrizi, F., and P. Cataldi, "Cross-layer
              Identities Management in ITS Stations", The 10th
              International Conference on ITS Telecommunications,
              November 2010.

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

   [SANA]     Hwang, T. and A. Whyman, "Transmission J. Jeong, "SANA: Safety-Aware Navigation
              Application for Pedestrian Protection in Vehicular
              Networks", Springer Lecture Notes in Computer Science
              (LNCS), Vol. 9502, December 2015.

   [CASD]     Shen, Y., Jeong, J., Oh, T., and S. Son, "CASD: A
              Framework of IPv6 Packets
              over Overlay Multilink Network (OMNI) Interfaces", draft-
              templin-6man-omni-interface-97 (work Context-Awareness Safety Driving in progress), Vehicular
              Networks", International Workshop on Device Centric Cloud
              (DC2), March
              2021.

   [RFC2710]  Deering, S., Fenner, W., and B. Haberman, "Multicast
              Listener Discovery (MLD) 2016.

   [CA-Cruise-Control]
              California Partners for IPv6", RFC 2710, October
              1999.

   [RFC3753]  Manner, J. Advanced Transportation Technology
              (PATH), "Cooperative Adaptive Cruise Control", Available:
              http://www.path.berkeley.edu/research/automated-and-
              connected-vehicles/cooperative-adaptive-cruise-control,
              2017.

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

   [FirstNet] U.S. National Telecommunications and M. Kojo, "Mobility Related Terminology",
              RFC 3753, June 2004.

   [RFC3810]  Vida, R. Information
              Administration (NTIA), "First Responder Network Authority
              (FirstNet)", 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.

   [SignalGuru]
              Koukoumidis, E., Peh, L., and L. Costa, "Multicast Listener Discovery
              Version 2 (MLDv2) M. Martonosi, "SignalGuru:
              Leveraging Mobile Phones for IPv6", RFC 3810, Collaborative Traffic Signal
              Schedule Advisory", ACM MobiSys, June 2004.

   [RFC3849]  Huston, G., Lord, A., 2011.

   [Fuel-Efficient]
              van de Hoef, S., H. Johansson, K., and P. Smith, "IPv6 Address Prefix
              Reserved for Documentation", RFC 3849, July 2004.

   [RFC3971]  Arkko, D. V. Dimarogonas,
              "Fuel-Efficient En Route Formation of Truck Platoons",
              IEEE Transactions on Intelligent Transportation Systems,
              January 2018.

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

   [NHTSA-ACAS-Report]
              National Highway Traffic Safety Administration (NHTSA),
              "Final Report of Automotive Collision Avoidance Systems
              (ACAS) Program", DOT HS 809 080, August 2000.

   [CBDN]     Kim, J., Kempf, Kim, S., Jeong, J., Zill, B., and P. Nikander, "SEcure
              Neighbor Discovery (SEND)", RFC 3971, March 2005.

   [RFC4086]  Eastlake 3rd, D., Schiller, Kim, H., Park, J., and S. Crocker,
              "Randomness Requirements T.
              Kim, "CBDN: Cloud-Based Drone Navigation for Security", RFC 4086, Efficient
              Battery Charging in Drone Networks", IEEE Transactions on
              Intelligent Transportation Systems, November 2019.

   [In-Car-Network]
              Lim, H., Volker, L., and D. Herrscher, "Challenges in a
              Future IP/Ethernet-based In-Car Network for Real-Time
              Applications", ACM/EDAC/IEEE Design Automation Conference
              (DAC), June
              2005.

   [RFC4193]  Hinden, R. 2011.

   [Scrambler-Attack]
              Bloessl, B., Sommer, C., Dressier, F., and B. Haberman, "Unique Local IPv6 Unicast
              Addresses", RFC 4193, October 2005.

   [RFC4301]  Kent, S. D. Eckhoff,
              "The Scrambler Attack: A Robust Physical Layer Attack on
              Location Privacy in Vehicular Networks", IEEE 2015
              International Conference on Computing, Networking and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, December 2005.

   [RFC4302]  Kent,
              Communications (ICNC), February 2015.

   [Bitcoin]  Nakamoto, S., "IP Authentication Header", RFC 4302, December
              2005.

   [RFC4303]  Kent, "Bitcoin: A Peer-to-Peer Electronic Cash
              System", URL: https://bitcoin.org/bitcoin.pdf, May 2009.

   [Vehicular-BlockChain]
              Dorri, A., Steger, M., Kanhere, S., "IP Encapsulating and R. Jurdak,
              "BlockChain: A Distributed Solution to Automotive Security Payload (ESP)",
              RFC 4303,
              and Privacy", IEEE Communications Magazine, Vol. 55, No.
              12, December 2005.

   [RFC4308]  Hoffman, 2017.

   [IPoWIRELESS]
              Thubert, P., "Cryptographic Suites for IPsec", RFC 4308,
              December 2005.

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor "IPv6 Neighbor Discovery for IP Version 6 (IPv6)", RFC 4861,
              September 2007.

   [RFC4862]  Thomson, S., Narten, T., on Wireless
              Networks", Work in Progress, Internet-Draft, draft-
              thubert-6man-ipv6-over-wireless-09, May 2021,
              <https://datatracker.ietf.org/doc/html/draft-thubert-6man-
              ipv6-over-wireless-09>.

   [RFC6959]  McPherson, D., Baker, F., and T. Jinmei, "IPv6 Stateless J. Halpern, "Source Address Autoconfiguration",
              Validation Improvement (SAVI) Threat Scope", RFC 4862, September 2007.

   [RFC4941]  Narten, T., Draves, R., 6959, May
              2013, <https://www.rfc-editor.org/rfc/rfc6959>.

Appendix A.  Support of Multiple Radio Technologies for V2V

   Vehicular networks may consist of multiple radio technologies such as
   DSRC and S. Krishnan, "Privacy
              Extensions 5G V2X.  Although a Layer-2 solution can provide a support
   for Stateless Address Autoconfiguration multihop communications in
              IPv6", RFC 4941, September 2007.

   [RFC5213]  Gundavelli, S., Ed., Leung, K., Devarapalli, V.,
              Chowdhury, K., vehicular networks, the scalability
   issue related to multihop forwarding still remains when vehicles need
   to disseminate or forward packets toward multihop-away destinations.
   In addition, the IPv6-based approach for V2V as a network layer
   protocol can accommodate multiple radio technologies as MAC
   protocols, such as DSRC and 5G V2X.  Therefore, the existing IPv6
   protocol can be augmented through the addition of a virtual interface
   (e.g., Overlay Multilink Network (OMNI) Interface [OMNI]) and/or
   protocol changes in order to support both wireless single-hop/
   multihop V2V communications and multiple radio technologies in
   vehicular networks.  In such a way, vehicles can communicate with
   each other by V2V communications to share either an emergency
   situation or road hazard information in a highway having multiple
   kinds of radio technologies.

Appendix B. Patil, "Proxy Mobile IPv6",
              RFC 5213, August 2008.

   [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R.,  Support of Multihop V2X Networking

   The multihop V2X networking can be supported by RPL (IPv6 Routing
   Protocol for Low-Power and W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate Lossy Networks) [RFC6550] and Overlay
   Multilink Network Interface (OMNI) [OMNI].

   RPL defines an IPv6 routing protocol for low-power and lossy networks
   (LLN), mostly designed for home automation routing, building
   automation routing, industrial routing, and Certificate Revocation List
              (CRL) Profile", RFC 5280, May 2008.

   [RFC5415]  Calhoun, P., Montemurro, M., urban LLN routing.  It
   uses a destination oriented directed acyclic graph (DODAG) to
   construct routing paths for hosts in a network.  The DODAG uses an
   objective function (OF) for route selection and D. Stanley, "Control And
              Provisioning of Wireless Access Points (CAPWAP) Protocol
              Specification", RFC 5415, March 2009.

   [RFC5889]  Baccelli, E. optimization within
   the network.  A user can use different routing metrics to define an
   OF for a specific scenario.  RPL supports multipoint-to-point, point-
   to-multipoint, and M. Townsley, "IP Addressing Model point-to-point traffic, and the major traffic flow
   is the multipoint-to-point traffic.  For example, in Ad
              Hoc Networks", RFC 5889, September 2010.

   [RFC6250]  Thaler, D., "Evolution a highway
   scenario, a vehicle may not access an RSU directly because of the IP Model", RFC 6250, May
              2011.

   [RFC6275]  Perkins, C., Ed., Johnson, D.,
   distance of the DSRC coverage (up to 1 km).  In this case, the RPL
   can be extended to support a multihop V2I since a vehicle can take
   advantage of other vehicles as relay nodes to reach the RSU.  Also,
   RPL can be extended to support both multihop V2V and J. Arkko, "Mobility
              Support V2X in IPv6", RFC 6275, July 2011.

   [RFC6550]  Winter, T., Thubert, P., Brandt, A., Hui, J., Kelsey, R.,
              Levis, P., Pister, K., Struik, R., Vasseur, JP., the
   similar way.

   OMNI defines a protocol for the transmission of IPv6 packets over
   Overlay Multilink Network Interfaces that are virtual interfaces
   governing multiple physical network interfaces.  OMNI supports
   multihop V2V communication between vehicles in multiple forwarding
   hops via intermediate vehicles with OMNI links.  It also supports
   multihop V2I communication between a vehicle and an infrastructure
   access point by multihop V2V communication.  The OMNI interface
   supports an NBMA link model where multihop V2V and R.
              Alexander, "RPL: IPv6 Routing Protocol V2I communications
   use each mobile node's ULAs without need for Low-Power any DAD or MLD
   Messaging.

Appendix C.  Support of Mobility Management for V2I

   The seamless application communication between two vehicles or
   between a vehicle and
              Lossy Networks", RFC 6550, March 2012.

   [RFC6706BIS]
              Templin, F., "Automatic Extended Route Optimization
              (AERO)", draft-templin-intarea-6706bis-95 (work an infrastructure node requires mobility
   management in
              progress), March 2021.

   [RFC6830BIS]
              Farinacci, D., Fuller, V., Meyer, D., Lewis, D., vehicular networks.  The mobility management schemes
   include a host-based mobility scheme, network-based mobility scheme,
   and A.
              Cabellos, "The Locator/ID Separation Protocol (LISP)",
              draft-ietf-lisp-rfc6830bis-36 (work software-defined networking scheme.

   In the host-based mobility scheme (e.g., MIPv6), an IP-RSU plays a
   role of a home agent.  On the other hand, in progress), November
              2020.

   [RFC7149]  Boucadair, M. and C. Jacquenet, "Software-Defined
              Networking: A Perspective from within the network-based
   mobility scheme (e.g., PMIPv6, an MA plays a Service Provider
              Environment", RFC 7149, March 2014.

   [RFC7296]  Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., role of a mobility
   management controller such as a Local Mobility Anchor (LMA) in
   PMIPv6, which also serves vehicles as a home agent, and T.
              Kivinen, "Internet Key Exchange Protocol Version 2
              (IKEv2)", RFC 7296, October 2014.

   [RFC7333]  Chan, H., Liu, D., Seite, P., Yokota, H., an IP-RSU
   plays a role of an access router such as a Mobile Access Gateway
   (MAG) in PMIPv6 [RFC5213].  The host-based mobility scheme needs
   client functionality in IPv6 stack of a vehicle as a mobile node for
   mobility signaling message exchange between the vehicle and J. Korhonen,
              "Requirements home
   agent.  On the other hand, the network-based mobility scheme does not
   need such a client functionality 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.

   [RFC8028]  Baker, F. and B. Carpenter, "First-Hop Router Selection by
              Hosts a vehicle because the network
   infrastructure node (e.g., MAG in PMIPv6) as a Multi-Prefix Network", RFC 8028, November 2016.

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

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, August 2018.

   [RFC8691]  Benamar, N., Haerri, J., Lee, J., and T. Ernst, "Basic
              Support proxy mobility agent
   handles the mobility signaling message exchange with the home agent
   (e.g., LMA in PMIPv6) for IPv6 Networks Operating Outside the Context sake of the vehicle.

   There are a Basic Service Set over IEEE Std 802.11", RFC 8691,
              December 2019.

   [SAINT]    Jeong, J., 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., Lee, J., Jeong, H., Jeong, J., Lee, E., scalability issue and D.
              Du, "SAINT+: Self-Adaptive Interactive Navigation Tool+ a route optimization issue in the
   network-based mobility scheme (e.g., PMIPv6) when an MA covers a
   large vehicular network governing many IP-RSUs.  In this case, a
   distributed mobility scheme (e.g., DMM [RFC7429]) can mitigate the
   scalability issue by distributing multiple MAs in the vehicular
   network such that they are positioned closer to vehicles for Emergency Service Delivery Optimization",
              IEEE Transactions on Intelligent Transportation Systems,
              June 2017.

   [SANA]     Hwang, T. route
   optimization and J. Jeong, "SANA: Safety-Aware Navigation
              Application for Pedestrian Protection in Vehicular
              Networks", Springer Lecture Notes bottleneck mitigation in Computer Science
              (LNCS), Vol. 9502, December 2015.

   [Scrambler-Attack]
              Bloessl, B., Sommer, C., Dressier, F., and D. Eckhoff,
              "The Scrambler Attack: A Robust Physical Layer Attack on
              Location Privacy a central MA in Vehicular Networks", IEEE 2015
              International Conference on Computing, Networking the
   network-based mobility scheme.  All these mobility approaches (i.e.,
   a host-based mobility scheme, network-based mobility scheme, and
              Communications (ICNC), February 2015.

   [SignalGuru]
              Koukoumidis, E., Peh, L.,
   distributed mobility scheme) and M. Martonosi, "SignalGuru:
              Leveraging Mobile Phones for Collaborative Traffic Signal
              Schedule Advisory", ACM MobiSys, June 2011.

   [TR-22.886-3GPP]
              3GPP, "Study on Enhancement a hybrid approach of 3GPP Support for 5G V2X
              Services", 3GPP TR 22.886/Version 16.2.0, December 2018.

   [Truck-Platooning]
              California Partners for Advanced Transportation Technology
              (PATH), "Automated Truck Platooning", 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/Version 16.2.0, December 2019.

   [TS-23.287-3GPP]
              3GPP, "Architecture Enhancements for 5G System (5GS) a combination
   of them need to
              Support Vehicle-to-Everything (V2X) Services", 3GPP
              TS 23.287/Version 16.2.0, March 2020.

   [UAM-ITS]  Templin, F., "Urban Air Mobility Implications for
              Intelligent Transportation Systems", draft-templin-ipwave-
              uam-its-04 (work in progress), January 2021.

   [Vehicular-BlockChain]
              Dorri, A., Steger, M., Kanhere, S., and R. Jurdak,
              "BlockChain: A Distributed Solution provide an efficient mobility service to Automotive Security vehicles
   moving fast and Privacy", IEEE Communications Magazine, Vol. 55, No.
              12, December 2017.

   [VIP-WAVE]
              Cespedes, S., Lu, N., moving along with the relatively predictable
   trajectories along the roadways.

   In vehicular networks, the control plane can be separated from the
   data plane for efficient mobility management and X. Shen, "VIP-WAVE: On data forwarding by
   using the
              Feasibility concept of IP Communications in 802.11p Vehicular
              Networks", IEEE Transactions on Intelligent Transportation
              Systems, vol. 14, no. 1, March 2013.

   [WAVE-1609.0]
              IEEE 1609 Working Group, "IEEE Guide for Wireless Access Software-Defined Networking (SDN)
   [RFC7149][DMM-FPC].  Note that Forwarding Policy Configuration (FPC)
   in Vehicular Environments (WAVE) - Architecture", IEEE Std
              1609.0-2013, March 2014.

   [WAVE-1609.2]
              IEEE 1609 Working Group, "IEEE Standard for Wireless
              Access [DMM-FPC], which is a flexible mobility management system, can
   manage the separation of data-plane and control-plane in Vehicular Environments - Security Services for
              Applications DMM.  In
   SDN, the control plane and Management Messages", IEEE Std
              1609.2-2016, March 2016.

   [WAVE-1609.3]
              IEEE 1609 Working Group, "IEEE Standard data plane are separated for Wireless
              Access the efficient
   management of forwarding elements (e.g., switches and routers) where
   an SDN controller configures the forwarding elements in Vehicular Environments (WAVE) - Networking
              Services", IEEE Std 1609.3-2016, April 2016.

   [WAVE-1609.4]
              IEEE 1609 Working Group, "IEEE Standard a centralized
   way and they perform packet forwarding according to their forwarding
   tables that are configured by the SDN controller.  An MA as an SDN
   controller needs to efficiently configure and monitor its IP-RSUs and
   vehicles for Wireless
              Access in Vehicular Environments (WAVE) - Multi-Channel
              Operation", IEEE Std 1609.4-2016, March 2016. mobility management, location management, and security
   services.

Appendix A. D.  Acknowledgments

   This work was supported by Institute of Information & Communications
   Technology Planning & Evaluation (IITP) grant funded by the Korea
   MSIT (Ministry of Science and ICT) (R-20160222-002755, Cloud based
   Security Intelligence Technology Development for the Customized
   Security Service Provisioning).

   This work was supported in part by the MSIT, Korea, under the ITRC
   (Information Technology Research Center) support program (IITP-
   2020-2017-0-01633)
   2021-2017-0-01633) supervised by the IITP.

   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).

   This work was supported in part by the Cisco University Research
   Program Fund, Grant # 2019-199458 (3696), and by ANID Chile Basal
   Project FB0008.

Appendix B. E.  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), Francois Simon (Pilot),
   Sri Gundavelli (Cisco), Erik Nordmark, Dirk von Hugo (Deutsche
   Telekom), Pascal Thubert (Cisco), Carlos Bernardos (UC3M), Russ
   Housley (Vigil Security), Suresh Krishnan (Kaloom), Nancy Cam-Winget
   (Cisco), Fred L.  Templin (The Boeing Company), Jung-Soo Park (ETRI),
   Zeungil (Ben) Kim (Hyundai Motors), Kyoungjae Sun (Soongsil
   University), Zhiwei Yan (CNNIC), YongJoon Joe (LSware), Peter E.  Yee
   (Akayla), and Erik Kline.  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 NIC Chile Research Labs Universidad de Chile Av.
   Blanco Encalada 1975 Santiago Chile Phone: +56 2 29784093 EMail:
   scespede@niclabs.cl

   Jerome Haerri Communication Systems Department EURECOM
   Sophia-Antipolis 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 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

Author's Address

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

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