IPv6 Wireless Access in Vehicular Environments (IPWAVE): Problem Statement and Use Cases
draft-ietf-ipwave-vehicular-networking-23
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 9365.
|
|
|---|---|---|---|
| Author | Jaehoon Paul Jeong | ||
| Last updated | 2021-09-02 | ||
| Replaces | draft-ietf-ipwave-vehicular-networking-survey, draft-ietf-ipwave-problem-statement | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
| Reviews |
INTDIR Telechat review
(of
-27)
by Pascal Thubert
Ready w/issues
ARTART Telechat review
(of
-27)
by Jim Fenton
Almost ready
|
||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Carlos J. Bernardos | ||
| Shepherd write-up | Show Last changed 2020-07-29 | ||
| IESG | IESG state | Became RFC 9365 (Informational) | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | Erik Kline | ||
| Send notices to | Carlos Bernardos <cjbc@it.uc3m.es> | ||
| IANA | IANA review state | Version Changed - Review Needed |
draft-ietf-ipwave-vehicular-networking-23
IPWAVE Working Group J. Jeong, Ed.
Internet-Draft Sungkyunkwan University
Intended status: Informational 2 September 2021
Expires: 6 March 2022
IPv6 Wireless Access in Vehicular Environments (IPWAVE): Problem
Statement and Use Cases
draft-ietf-ipwave-vehicular-networking-23
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.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 6 March 2022.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Simplified BSD License text
as described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1. V2V . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2. V2I . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.3. V2X . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4. Vehicular Networks . . . . . . . . . . . . . . . . . . . . . 12
4.1. Vehicular Network Architecture . . . . . . . . . . . . . 14
4.2. V2I-based Internetworking . . . . . . . . . . . . . . . . 15
4.3. V2V-based Internetworking . . . . . . . . . . . . . . . . 18
5. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 22
5.1. Neighbor Discovery . . . . . . . . . . . . . . . . . . . 23
5.1.1. Link Model . . . . . . . . . . . . . . . . . . . . . 25
5.1.2. MAC Address Pseudonym . . . . . . . . . . . . . . . . 27
5.1.3. Routing . . . . . . . . . . . . . . . . . . . . . . . 27
5.2. Mobility Management . . . . . . . . . . . . . . . . . . . 29
6. Security Considerations . . . . . . . . . . . . . . . . . . . 31
6.1. Security Threats in Neighbor Discovery . . . . . . . . . 32
6.2. Security Threats in Mobility Management . . . . . . . . . 33
6.3. Other Threats . . . . . . . . . . . . . . . . . . . . . . 33
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 34
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.1. Normative References . . . . . . . . . . . . . . . . . . 35
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 . . . . . . . 46
Appendix D. Acknowledgments . . . . . . . . . . . . . . . . . . 47
Appendix E. Contributors . . . . . . . . . . . . . . . . . . . . 48
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 49
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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], 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].
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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:
* 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].
* 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].
* DMM: "Distributed Mobility Management" [RFC7333][RFC7429].
* Edge Computing (EC): It is the local computing near an access
network (i.e., edge network) for the sake of vehicles and
pedestrians.
* Edge Computing Device (ECD): It is a computing device (or server)
for edge computing for the sake of vehicles and pedestrians.
* 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.
* 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
Internet-of-Things (IoT) device). It has at least one IP
interface that runs in IEEE 802.11-OCB and has an "OBU"
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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].
* 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].
* 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.
* 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.
* 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].
* 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'.
* 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].
* 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
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(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.
* 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.
* 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.
* Vehicular Cloud: A cloud infrastructure for vehicular networks,
having compute nodes, storage nodes, and network forwarding
elements (e.g., switch and router).
* V2D: "Vehicle to Device". It is the wireless communication
between a vehicle and a device (e.g., smartphone and IoT device).
* 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).
* 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).
* 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).
* 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.
* VIP: "Vehicular Internet Protocol". It is an IPv6 extension for
vehicular networks including V2V, V2I, and V2X.
* VMM: "Vehicular Mobility Management". It is an IPv6-based
mobility management for vehicular networks.
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* VND: "Vehicular Neighbor Discovery". It is an IPv6 ND extension
for vehicular networks.
* VSP: "Vehicular Security and Privacy". It is an IPv6-based
security and privacy for vehicular networks.
* 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
* Context-aware navigation for safe driving and collision avoidance;
* Cooperative adaptive cruise control in a roadway;
* Platooning in a highway;
* Cooperative environment sensing;
* Collision avoidance service of end systems of Urban Air Mobility
(UAM) [UAM-ITS].
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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
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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].
To support applications of these V2V use cases, the required
functions of IPv6 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
* Navigation service;
* Energy-efficient speed recommendation service;
* Accident notification service;
* Electric vehicle (EV) charging service;
* UAM navigation service with efficient battery charging.
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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
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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 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 include IPv6-based packet exchange, transport-layer
session continuity, and secure, safe communication between a vehicle
and an infrastructure node (e.g., IP-RSU) in the vehicular 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 protocol changes
in order to support wireless multihop V2X 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) as packet
forwarders. Thus, IPv6 needs to be extended for multihop V2X or
V2I2X communications.
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To support applications of these V2X use cases, the required
functions of IPv6 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 the context for vehicular networks supporting
V2V, V2I, and V2X 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.
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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
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4.1. Vehicular Network Architecture
Figure 1 shows an example vehicular network architecture for V2I and
V2V in a road network. The vehicular network architecture contains
vehicles (including IP-OBU), IP-RSUs, Mobility Anchor, Traffic
Control Center, and Vehicular Cloud as 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.
Existing network architectures, such as the network architectures of
PMIPv6 [RFC5213], RPL (IPv6 Routing Protocol for Low-Power and Lossy
Networks) [RFC6550], and 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. Refer to
Appendix B for the detailed discussion on multihop V2X networking by
RPL and OMNI.
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
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 a "Bring-Your-Own-Addresses (BYOA)" technique using their
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own IPv6 Unique Local Addresses (ULAs) [RFC4193] over the wireless
network, which does not require the messaging (e.g., Duplicate
Address Detection (DAD)) of IPv6 Stateless Address Autoconfiguration
(SLAAC) [RFC4862].
In wireless subnets in vehicular networks (e.g., Subnet1 and Subnet2
in Figure 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.
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 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]). This document describes issues in mobility
management for vehicular networks in Section 5.2.
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 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) and servers (e.g., ECDs, navigation server, and
DNS server) in its internal network.
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A vehicle's internal network often uses Ethernet to interconnect
Electronic Control Units (ECUs) in the vehicle. The internal network
can support Wi-Fi and Bluetooth 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 a vehicle and an EN. It is reasonable to consider the
interaction between the internal network and 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
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As shown in 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.
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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.
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(*)<..........>(*)
(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 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 communicate
with another host (Host3) in Vehicle2 for a vehicular service through
Vehicle1's moving network, a wireless link between IP-OBU1 and IP-
OBU2, and Vehicle2's moving network.
As a V2V use case in Section 3.1, Figure 4 shows the linear network
topology of platooning vehicles for V2V communications where Vehicle3
is the leading vehicle with a driver, and Vehicle2 and Vehicle1 are
the following vehicles without drivers.
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(*)<..................>(*)<..................>(*)
| | |
+-----------+ +-----------+ +-----------+
| | | | | |
| +-------+ | | +-------+ | | +-------+ |
| |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
moving networks of three vehicles in the same VANET. For example,
Host1 in Vehicle1 can communicate with Host3 in Vehicle3 via IP-OBU1
in Vehicle1, IP-OBU2 in Vehicle2, and IP-OBU3 in Vehicle3 in the
VANET, as shown in the figure.
In this section, the link between two vehicles is assumed to be
stable for single-hop wireless communication regardless of the sight
relationship such as line of sight and non-line of sight, as shown in
Figure 3. Even in Figure 4, the three vehicles are connected to each
other with a linear topology, however, multihop V2V communication can
accommodate any network topology (i.e., an arbitrary graph) over
VANET routing protocols.
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(*)<..................>(*)<..................>(*)
| | |
+-----------+ +-----------+ +-----------+
| | | | | |
| +-------+ | | +-------+ | | +-------+ |
| |IP-OBU1| | | |IP-RSU1| | | |IP-OBU3| |
| +-------+ | | +-------+ | | +-------+ |
| ^ | | ^ | | ^ |
| | |=====> | | | | | |=====>
| v | | v | | v |
| +-------+ | | +-------+ | | +-------+ |
| | Host1 | | | | Host2 | | | | Host3 | |
| +-------+ | | +-------+ | | +-------+ |
| | | | | |
+-----------+ +-----------+ +-----------+
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 can communicate with Host3 in Vehicle3 via
IP-OBU1 in Vehicle1, IP-RSU1 in EN1, and IP-OBU3 in Vehicle3 in the
VANET, as shown in 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 the difference versions of Optimized
Link State Routing Protocol (OLSR) [RFC3626] [RFC7181] [RFC7188]
[RFC7722] [RFC7779] [RFC8218] and 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 neighbors. However, an ND protocol in vehicular
networks 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.
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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 an 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., vehicle collision), so IPv6
protocol exchanges need to support this order of magnitude for
application message exchanges. Also, considering the communication
range of DSRC (up to 1km) and 100km/h as the speed limit in highway,
the lifetime of a link between a vehicle and an IP-RSU is 72 seconds,
and the lifetime of a link between two vehicles is 36 seconds. Note
that if two vehicles are moving in the opposite directions in a
roadway, the 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 and the 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 nodes (e.g., vehicle and IP-RSU) needs to
be considered because it may affect the lifetime of a session
involving the link. The lifetime of a session varies depending on
the session's type such as a web surfing, voice call over IP, DNS
query, and context-aware navigation (in Section 3.1). Regardless of
a session's type, to guide all the IPv6 packets to their destination
host(s), IP mobility should be supported for the session. In a V2V
scenario (e.g., context-aware navigation), the IPv6 packets of a
vehicle should be delivered to relevant vehicles in 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 vehicular networks.
Therefore, the time constraint of a wireless link has a major impact
on IPv6 Neighbor Discovery (ND). Mobility Management (MM) is also
vulnerable to disconnections that occur before the completion of
identity verification and tunnel management. This is especially true
given the unreliable nature of wireless communication. Meanwhile,
the bandwidth of the wireless link determined by the lower layers
(i.e., link and PHY layers) can affect the transmission time of
control messages of the upper layers (e.g., IPv6) and the continuity
of sessions in the higher layers (e.g., IPv6, TCP, and UDP). Hence
the bandwidth selection according to Modulation and Coding Scheme
(MCS) also affects the vehicular network connectivity. Note that
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usually the higher bandwidth gives the shorter communication range
and the higher packet error rate at the receiving side, which may
reduce the reliability of control message exchanges of the 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 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 efficient and reliable support of multicast
and unicast from the link layer for various network operations such
as MAC Address Resolution (AR), DAD, MLD and 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 configured with
a link-local IPv6 address or a global IPv6 address, and run IPv6 ND.
The requirements for IPv6 ND for vehicular networks are efficient DAD
and NUD operations. An efficient DAD is required to reduce the
overhead of the DAD packets during a vehicle's travel in a road
network, which can guarantee the uniqueness of a vehicle's global
IPv6 address. An efficient NUD is required to reduce the overhead of
the NUD packets during a vehicle's travel in a road network, which
can guarantee the accurate neighborhood information of a vehicle in
terms of adjacent vehicles and RSUs.
The legacy DAD assumes that a node with an IPv6 address can reach any
other node with the scope of its address at the time it claims its
address, and can hear any future claim for that address by another
party within the scope of its address for the duration of 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 (as
Registrar in RPL) to check the uniqueness of an IPv6 address that
will be configured by a vehicle as DAD. Also, the partitioning of 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 existence of a vehicle
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under the network coverage of the MA or IP-RSU as NUD. Thus, SLAAC
needs to prevent IPv6 address duplication due to the merging of
VANETs, and IPv6 ND needs to detect unreachable neighboring vehicles
due to the partitioning of a VANET. According to the merging and
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 vehicles can communicate with each other when there exists
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 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 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 accident notification) with each other with a short
interval suggested by NHTSA (National Highway Traffic Safety
Administration) [NHTSA-ACAS-Report]. Since the partitioning and
merging of vehicular networks may require re-perform the DAD process
repeatedly, the link scope of vehicles may be limited to a small
area, which may delay the exchange of driving safety messages.
Driving safety messages can include a 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 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 vehicle speed and
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 operational
setting or an optimization point particularly for vehicular networks.
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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 to work to
support those IPv6-based safety applications efficiently.
From the interoperability point of view, in IPv6-based vehicular
networking, IPv6 ND should have minimum changes with the legacy IPv6
ND used in 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 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 them in the vehicular network including VANETs and
IP-RSUs. This subnet model allows vehicles with the same prefix to
communicate with each other via a combination of multihop V2V and
multihop V2I with VANETs and 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 connectivity
among neighboring interfaces [RFC6250]. However, radio interference
and different levels of transmission power may cause asymmetric links
to appear in vehicular wireless links. As a result, a new vehicular
link model needs to consider the asymmetry of dynamically changing
vehicular wireless links.
There is a relationship between a link and a prefix, besides the
different scopes that are expected from the link-local and global
types of IPv6 addresses. In an IPv6 link, it is defined that all
interfaces which are configured with the same subnet prefix and with
on-link bit set can communicate with each other on an IPv6 link.
However, the vehicular link model needs to define the relationship
between a link and a prefix, considering the 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 Figure 4. When two
vehicles belong to the same VANET, but they are out 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 to VANETs in vehicular networks. Even though two
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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 the multihop network connectivity
between them. Thus, in this case, the concept of an on-link IPv6
prefix does not hold because two vehicles with the same on-link IPv6
prefix cannot communicate directly with each other. Also, when two
vehicles are located in two different VANETs with the 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 multihop fashion, for example, when they are Vehicle1
and Vehicle3, as shown in Figure 4.
From the previous observation, a vehicular link model should consider
the frequent partitioning and merging of VANETs due to vehicle
mobility. Therefore, the vehicular link model needs to use an on-
link prefix and off-link prefix according to the network topology of
vehicles such as a one-hop reachable network and a 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 same
prefix are not reachable from each other in one hop due to either the
multihop topology in the VANET or multiple partitions, the prefix
should be off-link. In most cases in vehicular networks, due to the
partitioning and merging of VANETs, and the multihop network topology
of VANETS, off-link prefixes will be used for vehicles as default.
The vehicular link model needs to support multihop routing in a
connected VANET where the vehicles with the same global-scope IPv6
prefix (or the same IPv6 ULA prefix) are connected in one hop or
multiple hops. It also needs to support the multihop routing in
multiple connected VANETs through infrastructure nodes (e.g., IP-RSU)
where they are connected to the infrastructure. For example, in
Figure 1, suppose that Vehicle1, Vehicle2, 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
to communicate with each other directly via VANET rather than
indirectly via IP-RSUs. On the other hand, when Vehicle1 and
Vehicle3 are far away from direct communication range in separate
VANETs and under two different IP-RSUs, they can communicate with
each other through the relay 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 can play the role of a relay node for those VANETs.
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Thus, in IPv6-based vehicular networking, the vehicular link model
should have minimum changes for interoperability with standard IPv6
links in an efficient fashion to support IPv6 DAD, MLD and NUD
operations.
5.1.2. MAC Address Pseudonym
For the protection of drivers' privacy, a pseudonym of a MAC address
of a vehicle's network interface should be used, so that the MAC
address can be changed periodically. However, although such a
pseudonym of a MAC address can protect to some extent the privacy of
a vehicle, it may not be able to resist attacks on vehicle
identification by other fingerprint information, for example, the
scrambler seed embedded in IEEE 802.11-OCB frames [Scrambler-Attack].
The pseudonym of a MAC address affects an IPv6 address based on the
MAC address, and a transport-layer (e.g., TCP and SCTP) session with
an IPv6 address pair. However, the pseudonym handling is not
implemented and tested yet for applications on IP-based vehicular
networking.
In the ETSI standards, for the sake of security and privacy, an ITS
station (e.g., vehicle) can use pseudonyms for its network interface
identities (e.g., MAC address) and the corresponding IPv6 addresses
[Identity-Management]. Whenever the network interface identifier
changes, the IPv6 address based on the network interface identifier
needs to be updated, and the uniqueness of 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 Mobile Ad Hoc Networks (MANET) routing protocol may
be required to support both unicast and multicast in the links of the
subnet with the same IPv6 prefix. However, it will be costly to run
both vehicular ND and 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 air to check the neighborhood of each vehicle and compute the
routing information in a VANET with a dynamic network topology
because the IPv6 ND is used to check the neighborhood of each
vehicle. Thus, the vehicular routing needs to take advantage of the
IPv6 ND to minimize its control overhead.
RPL [RFC6550] defines a routing protocol for low-power and lossy
networks, which constructs and maintains Destination-Oriented
Directed Acyclic Graphs (DODAGs) optimized by an Objective Function
(OF). A defined OF provides route selection and optimization within
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an RPL topology. A node in a DODAG discovers and maintains the
upward routes toward the root node of the DODAG. RPL uses a Distance
Vector (DV) approach, with lazy maintenance and stretched anisotropic
routing. It is well-designed to reduce the topological knowledge and
routing state that needs to be exchanged. As a result, the routing
protocol overhead is minimized, which allows either highly
constrained stable networks or less constrained, highly dynamic
networks. Refer to Appendix B for the detailed description of RPL
for multihop V2X networking.
An address registration extension for 6LoWPAN (IPv6 over Low-Power
Wireless Personal Area Network) in [RFC8505] can support light-weight
mobility for nodes moving through different parents. [RFC8505], as
opposed to [RFC4861], is stateful and proactively installs the ND
cache entries, which saves broadcasts and provides a deterministic
presence information for IPv6 addresses. Mainly it updates the
Address Registration Option (ARO) of ND defined in [RFC6775] to
include a status field that can indicate the movement of a node and
optionally a Transaction ID (TID) field, i.e., a sequence number that
can be used to determine the most recent location of a node. Thus,
RPL can use the information provided by the Extended ARO (EARO)
defined in [RFC8505] to deal with a certain level of node mobility.
When a leaf node moves to the coverage of another parent node, it
should de-register its addresses to the previous parent node and
register itself with a new parent node along with an incremented TID.
RPL can be used in IPv6-based vehicular networks, but it is primarily
designed for lossy networks, which puts energy efficiency first. For
using it in IPv6-based vehicular networks, there have not been actual
experiences and practical implementations for vehicular networks,
though it was tested in IoT low-power and lossy networks (LLN)
scenarios.
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 mobility of vehicles, network
fragmentation may not be detected quickly and the routing of packets
between vehicles or between a vehicle and an infrastructure node may
fail.
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5.2. Mobility Management
The seamless connectivity and timely data exchange between two end
points requires efficient mobility management including location
management and handover. Most vehicles are equipped with a GPS
receiver as part of a dedicated navigation system or a corresponding
smartphone App. Note that the GPS receiver may not provide vehicles
with accurate location information in adverse environments such as a
building area or a tunnel. The location precision can be improved
with assistance of the IP-RSUs or a cellular system with a 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 the vehicular
infrastructure (having IP-RSUs and an MA in TCC). This vehicular
infrastructure can predict the future positions of the vehicles from
their mobility information (i.e., the current position, speed,
direction, and trajectory) for efficient mobility management (e.g.,
proactive handover). For a better proactive handover, link-layer
parameters, such as the signal strength of a link-layer frame (e.g.,
Received Channel Power Indicator (RCPI) [VIP-WAVE]), can be used to
determine the moment of a handover between IP-RSUs along with
mobility information.
By predicting a vehicle's mobility, the vehicular infrastructure
needs to better support IP-RSUs to perform efficient SLAAC, data
forwarding, horizontal handover (i.e., handover in wireless links
using a homogeneous radio technology), and vertical handover (i.e.,
handover in wireless links using heterogeneous radio technologies) in
advance along with the movement of the vehicle.
For example, as shown in Figure 1, when a vehicle (e.g., Vehicle2) is
moving from the coverage of an IP-RSU (e.g., IP-RSU1) into the
coverage of another IP-RSU (e.g., IP-RSU2) belonging to a different
subnet, the IP-RSUs can proactively support the IPv6 mobility of the
vehicle, while performing the SLAAC, data forwarding, and handover
for the sake of the vehicle.
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For a mobility management scheme in a domain, where the wireless
subnets of multiple IP-RSUs share the same prefix, an efficient
vehicular-network-wide DAD is required. If DHCPv6 is used to assign
a unique IPv6 address to each vehicle 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]), DAD is
not required because the IPv6 address of a vehicle's external
wireless interface is guaranteed to be unique. There is a tradeoff
between the prefix usage efficiency and DAD overhead. Thus, the IPv6
address autoconfiguration for vehicular networks needs to consider
this tradeoff to 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 networks needs to consider the minimization of the cost of
DAD with the help of an infrastructure node (e.g., IP-RSU and MA).
Using an infrastructure prefix over VANET allows direct routability
to the Internet through the multihop V2I toward an IP-RSU. On the
other hand, a BYOA does not allow such direct routability to the
Internet since the BYOA is not topologically correct, that is, not
routable in the Internet. In addition, a vehicle configured with a
BYOA needs a tunnel home (e.g., IP-RSU) connected to the Internet,
and the vehicle needs to know which neighboring vehicle is reachable
inside the VANET toward the tunnel home. There is nonnegligible
control overhead to set up and maintain routes to such a tunnel home
over the VANET.
For the case of a multihomed network, a vehicle can follow the first-
hop router selection rule described in [RFC8028]. For example, an
IP-OBU inside a 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 routers, the default router selection,
source address selection, and packet redirect process should follow
the guidelines in [RFC8028]. That is, the vehicle should select its
default router for 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 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
the wireless link should be avoided for performance efficiency.
Also, in vehicular networks, asymmetric links sometimes exist and
must be considered for wireless communications such as V2V and V2I.
Therefore, for the proactive and seamless IPv6 mobility of vehicles,
the vehicular infrastructure (including IP-RSUs and MA) needs to
efficiently perform the mobility management of the vehicles with
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their mobility information and link-layer information. Also, in
IPv6-based vehicular networking, IPv6 mobility management should have
minimum changes for the interoperability with the legacy IPv6
mobility management schemes such as PMIPv6, DMM, LISP, and AERO.
6. Security Considerations
This section discusses security and privacy for IPv6-based vehicular
networking. Security and privacy are paramount in V2I, V2V, and V2X
networking along with neighbor discovery and mobility management.
Vehicles and infrastructure must be authenticated in order to
participate in vehicular networking. For the authentication in
vehicular networks, vehicular cloud needs to support a kind of Public
Key Infrastructure (PKI) in an efficient way. To provide safe
interaction between vehicles or between a vehicle and infrastructure,
only authenticated nodes (i.e., vehicle and infrastructure node) can
participate in vehicular networks. Also, in-vehicle devices (e.g.,
ECU) and a driver/passenger's mobile devices (e.g., smartphone and
tablet PC) in a vehicle need to communicate with other in-vehicle
devices and another driver/passenger's mobile devices in another
vehicle, or other servers behind an IP-RSU in a secure way. Even
though a vehicle is perfectly authenticated and legitimate, it may be
hacked for running malicious applications to track and collect its
and other vehicles' information. In this case, an attack mitigation
process may be required to reduce the aftermath of malicious
behaviors.
For secure V2I communication, a secure channel (e.g., IPsec) between
a mobile router (i.e., IP-OBU) in a vehicle and a fixed router (i.e.,
IP-RSU) in an EN needs to be established, as shown in Figure 2
[RFC4301][RFC4302] [RFC4303][RFC4308] [RFC7296]. Also, for secure
V2V communication, a secure channel (e.g., IPsec) between a mobile
router (i.e., IP-OBU) in a vehicle and a mobile router (i.e., IP-OBU)
in another vehicle needs to be established, as shown in Figure 3.
For secure communication, an element in a vehicle (e.g., an in-
vehicle device 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 in a vehicular cloud (e.g., a
server). IEEE 1609.2 [WAVE-1609.2] specifies security services for
applications and management messages, but this WAVE specification is
optional. Thus, if the link layer does not support the security of a
WAVE frame, either the network layer or the transport layer needs to
support security services for the WAVE frames.
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6.1. Security Threats in Neighbor Discovery
For the classical 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.
[RFC6959] introduces threats enabled by IP source address spoofing.
This possibility indicates that vehicles and IP-RSUs need to filter
out suspicious ND traffic in advance. [RFC8928] introduces a
mechanism that protects the ownership of an address for 6loWPAN ND
from address theft and impersonation attacks. Based on the SEND
[RFC3971] mechanism, the authentication 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
approach [Vehicular-BlockChain] can be used. However, for a scenario
where a trustable router or an authentication path cannot be
obtained, it is desirable to find a solution in which vehicles and
infrastructures can authenticate each other without any support from
a third party.
When applying the classical IPv6 ND process to VANET, one of the
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 processing the network scan requests so that the
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 operational problems
in the classical IPv6 ND mechanism that can be vulnerable to
deliberate or accidental DoS attacks and suggests several
implementation guidelines and operational mitigation techniques for
those problems. Nevertheless, for running IPv6 ND in VANET, those
issues can be more acute since the movements of vehicles can be so
diverse that it leaves a large room for rogue behaviors, and the
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 is
assumed. Malicious nodes may disseminate wrong driving information
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(e.g., location, speed, and 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 the vehicular cloud. This authentication
can be used to identify the vehicle that will communicate with an
infrastructure node or another vehicle. In the case where a vehicle
has an internal network (called Moving Network) and elements in the
network (e.g., in-vehicle devices and a user's mobile devices), as
shown in Figure 2, the elements in the network need to be
authenticated individually for safe authentication. Also, Transport
Layer Security (TLS) certificates [RFC8446][RFC5280] can be used for
an element's authentication to allow secure E2E vehicular
communications between an element in a vehicle and another element in
a server in a vehicular cloud, or between an element in a vehicle and
another element in another vehicle.
6.2. Security Threats in Mobility Management
For mobility management, a 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 genuine or bogus
in mobility management. Also, the confidentiality of control packets
and data packets among IP-RSUs and MA, the E2E paths (e.g., tunnels)
need to be protected by secure communication channels. In addition,
to prevent bogus IP-RSUs and MA from interfering with the IPv6
mobility of vehicles, mutual authentication among them needs to be
performed by certificates (e.g., TLS certificate).
6.3. Other Threats
For the setup of a secure channel over IPsec or TLS, the multihop V2I
communications over DSRC or 5G V2X (or LTE V2X) is required in a
highway. In this case, multiple intermediate vehicles as relay nodes
can help forward association and authentication messages toward an
IP-RSU (gNodeB, or eNodeB) connected to an authentication server in
the vehicular cloud. In this kind of process, the authentication
messages forwarded by each vehicle can be delayed or lost, which may
increase the construction time of a connection or some vehicles may
not be able to be authenticated.
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Even though vehicles can be authenticated with valid certificates by
an authentication server in the vehicular cloud, the authenticated
vehicles may harm other vehicles. To deal with this kind of security
issue, for monitoring suspicious behaviors, vehicles' communication
activities can be 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.
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]. 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 prevent an adversary from tracking a vehicle 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 provided to each vehicle; that is, each vehicle
periodically updates its MAC address and its IPv6 address needs to be
updated accordingly by the MAC address change [RFC4086][RFC4941].
Such an update of the MAC and IPv6 addresses should not interrupt the
E2E communications between two vehicles (or between a vehicle and an
IP-RSU) 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 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
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8.1. Normative References
[RFC8691] Benamar, N., Haerri, J., Lee, J., and T. Ernst, "Basic
Support for IPv6 Networks Operating Outside the Context of
a Basic Service Set over IEEE Std 802.11", RFC 8691,
December 2019, <https://www.rfc-editor.org/rfc/rfc8691>.
[RFC8200] Deering, S. and 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 J. Arkko, "Mobility
Support in 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 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 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>.
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[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 C. Jacquenet, "Software-Defined
Networking: A Perspective from within a Service Provider
Environment", RFC 7149, March 2014,
<https://www.rfc-editor.org/rfc/rfc7149>.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and 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 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 IPv6", RFC 2710, October
1999, <https://www.rfc-editor.org/rfc/rfc2710>.
[RFC3810] Vida, R. and 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 M. Townsley, "IP Addressing Model in 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 Security", RFC 4086, June
2005, <https://www.rfc-editor.org/rfc/rfc4086>.
[RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in
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>.
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[RFC6250] Thaler, D., "Evolution of the 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
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 a 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 over Low-Power
Wireless Personal Area Network (6LoWPAN) Neighbor
Discovery", RFC 8505, November 2018,
<https://www.rfc-editor.org/rfc/rfc8505>.
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[RFC6775] Shelby, Z., Chakrabarti, S., Nordmark, E., and C. Bormann,
"Neighbor Discovery Optimization for IPv6 over Low-Power
Wireless Personal Area Networks (6LoWPANs)", RFC 6775,
November 2012, <https://www.rfc-editor.org/rfc/rfc6775>.
[RFC5881] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881, June
2010, <https://www.rfc-editor.org/rfc/rfc5881>.
[RFC6130] Clausen, T., Dearlove, C., and 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 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 Low-Power and
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 T. Clausen, "Optimized Link State Routing
Protocol Version 2 (OLSRv2) and 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 Optimized Link State Routing Protocol Version 2
(OLSRv2)", RFC 7722, December 2015,
<https://www.rfc-editor.org/rfc/rfc7722>.
[RFC7779] Rogge, H. and E. Baccelli, "Directional Airtime Metric
Based on Packet Sequence Numbers for Optimized Link State
Routing Version 2 (OLSRv2)", RFC 7779, April 2016,
<https://www.rfc-editor.org/rfc/rfc7779>.
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[RFC8218] Yi, J. and B. Parrein, "Multipath Extension for the
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 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 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 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 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 T. Clausen, "An Optimization for the
Mobile Ad Hoc Network (MANET) Neighborhood Discovery
Protocol (NHDP)", RFC 7466, March 2015,
<https://www.rfc-editor.org/rfc/rfc7466>.
8.2. Informative References
[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., Meyer, D., Lewis, D., and A.
Cabellos, "The Locator/ID Separation Protocol (LISP)",
Work in Progress, Internet-Draft, draft-ietf-lisp-
rfc6830bis-36, November 2020,
<https://datatracker.ietf.org/doc/html/draft-ietf-lisp-
rfc6830bis-36>.
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[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 A. Whyman, "Transmission of IP Packets
over Overlay Multilink Network (OMNI) Interfaces", Work in
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", 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", Work in Progress, Internet-
Draft, draft-ietf-dmm-fpc-cpdp-14, September 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.
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[IEEE-802.11p]
"Part 11: Wireless LAN Medium Access Control (MAC) and
Physical Layer (PHY) Specifications - Amendment 6:
Wireless Access in Vehicular Environments", IEEE Std
802.11p-2010, June 2010.
[IEEE-802.11-OCB]
"Part 11: Wireless LAN Medium Access Control (MAC) and
Physical Layer (PHY) Specifications", IEEE Std
802.11-2016, December 2016.
[WAVE-1609.0]
IEEE 1609 Working Group, "IEEE Guide for Wireless Access
in Vehicular Environments (WAVE) - 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 (WAVE) - Networking
Services", IEEE Std 1609.3-2016, April 2016.
[WAVE-1609.4]
IEEE 1609 Working Group, "IEEE Standard for Wireless
Access in Vehicular Environments (WAVE) - Multi-Channel
Operation", IEEE Std 1609.4-2016, March 2016.
[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.
[TS-23.285-3GPP]
3GPP, "Architecture Enhancements for V2X Services", 3GPP
TS 23.285/Version 16.2.0, December 2019.
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[TR-22.886-3GPP]
3GPP, "Study on Enhancement of 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 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 Context-Awareness Safety Driving in Vehicular
Networks", International Workshop on Device Centric Cloud
(DC2), March 2016.
[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.
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[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 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 M. Martonosi, "SignalGuru:
Leveraging Mobile Phones for Collaborative Traffic Signal
Schedule Advisory", ACM MobiSys, June 2011.
[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.
[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., Kim, S., Jeong, J., Kim, H., Park, J., and T.
Kim, "CBDN: Cloud-Based Drone Navigation for 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 2011.
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[Scrambler-Attack]
Bloessl, B., Sommer, C., Dressier, F., and D. Eckhoff,
"The Scrambler Attack: A Robust Physical Layer Attack on
Location Privacy in Vehicular Networks", IEEE 2015
International Conference on Computing, Networking and
Communications (ICNC), February 2015.
[Bitcoin] Nakamoto, S., "Bitcoin: A Peer-to-Peer Electronic Cash
System", URL: https://bitcoin.org/bitcoin.pdf, May 2009.
[Vehicular-BlockChain]
Dorri, A., Steger, M., Kanhere, S., and R. Jurdak,
"BlockChain: A Distributed Solution to Automotive Security
and Privacy", IEEE Communications Magazine, Vol. 55, No.
12, December 2017.
[IPoWIRELESS]
Thubert, P., "IPv6 Neighbor Discovery 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 J. Halpern, "Source Address
Validation Improvement (SAVI) Threat Scope", RFC 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 5G V2X. Although a Layer-2 solution can provide a 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 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.
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Appendix B. Support of Multihop V2X Networking
The multihop V2X networking can be supported by RPL (IPv6 Routing
Protocol for Low-Power and 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 urban LLN routing. It
uses a Destination-Oriented Directed Acyclic Graph (DODAG) to
construct routing paths for hosts (e.g., IoT devices) in a network.
The DODAG uses an objective function (OF) for route selection and
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 point-to-point traffic,
and the major traffic flow is the multipoint-to-point traffic. For
example, in a highway scenario, a vehicle may not access an RSU
directly because of the 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 V2X in the similar way.
RPL is primarily designed to minimize the control plane activity,
which is the relative amount of routing protocol exchanges versus
data traffic; this approach is beneficial for situations where the
power and bandwidth are scarce (e.g., an IoT LLN where RPL is
typically used today), but also in situations of high relative
mobility between the nodes in the network (also known as swarming,
e.g., within a variable set of vehicles with a similar global motion,
or a variable set of drones flying toward the same direction).
To reduce the routing exchanges, RPL leverages a Distance Vector (DV)
approach, which does not need a global knowledge of the topology, and
only optimizes the routes to and from the root, allowing Peer-to-Peer
(P2P) paths to be stretched. Although RPL installs its routes
proactively, it only maintains them lazily, that is, in reaction to
actual traffic, or as a slow background activity. Additionally, RPL
leverages the concept of an objective function (called OF), which
allows to adapt the activity of the routing protocol to use cases,
e.g., type, speed, and quality of the radios. RPL does not need
converge, and provides connectivity to most nodes most of the time.
The default route toward the root is maintained aggressively and may
change while a packet progresses without causing loops, so the packet
will still reach the root. There are two modes for routing in RPL
such as non-storing mode and storing mode. In non-storing mode, a
node inside the mesh/swarm that changes its point(s) of attachment to
the graph informs the root with a single unicast packet flowing along
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the default route, and the connectivity is restored immediately; this
mode is preferable for use cases where Internet connectivity is
dominant. On the other hand, in storing mode, the routing stretch is
reduced, for a better P2P connectivity, while the Internet
connectivity is restored more slowly, during the time for the DV
operation to operate hop-by-hop. While an RPL topology can quickly
scale up and down and fits the needs of mobility of vehicles, the
total performance of the system will also depend on how quickly a
node can form an address, join the mesh (including Authentication,
Authorization, and Accounting (AAA)), and manage its global mobility
to become reachable from another node outside the mesh.
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 V2I communications
use each mobile node's ULAs without need for 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 an infrastructure node requires mobility
management in vehicular networks. The mobility management schemes
include a host-based mobility scheme, network-based mobility scheme,
and 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 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) in
PMIPv6, which also serves vehicles as a home agent, and 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 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 with the home agent
(e.g., LMA in PMIPv6) for the sake of the vehicle.
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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 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 route
optimization and bottleneck mitigation in a central MA in the
network-based mobility scheme. All these mobility approaches (i.e.,
a host-based mobility scheme, network-based mobility scheme, and
distributed mobility scheme) and a hybrid approach of a combination
of them need to provide an efficient mobility service to vehicles
moving fast and 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 data forwarding by
using the concept of Software-Defined Networking (SDN)
[RFC7149][DMM-FPC]. Note that Forwarding Policy Configuration (FPC)
in [DMM-FPC], which is a flexible mobility management system, can
manage the separation of data-plane and control-plane in DMM. In
SDN, the control plane and data plane are separated for the efficient
management of forwarding elements (e.g., switches and routers) where
an SDN controller configures the forwarding elements 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.
Appendix 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-
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.
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Appendix 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, 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
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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: https://chrisshen.github.io
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
Gyeonggi-Do
16419
Republic of Korea
Phone: +82 31 299 4957
Email: pauljeong@skku.edu
URI: http://iotlab.skku.edu/people-jaehoon-jeong.php
Jeong, Ed. Expires 6 March 2022 [Page 49]