< draft-ietf-ipwave-vehicular-networking-28.txt   draft-ietf-ipwave-vehicular-networking-29.txt >
IPWAVE Working Group J. Jeong, Ed. IPWAVE Working Group J. Jeong, Ed.
Internet-Draft Sungkyunkwan University Internet-Draft Sungkyunkwan University
Intended status: Informational 30 March 2022 Intended status: Informational 19 May 2022
Expires: 1 October 2022 Expires: 20 November 2022
IPv6 Wireless Access in Vehicular Environments (IPWAVE): Problem IPv6 Wireless Access in Vehicular Environments (IPWAVE): Problem
Statement and Use Cases Statement and Use Cases
draft-ietf-ipwave-vehicular-networking-28 draft-ietf-ipwave-vehicular-networking-29
Abstract Abstract
This document discusses the problem statement and use cases of This document discusses the problem statement and use cases of
IPv6-based vehicular networking for Intelligent Transportation IPv6-based vehicular networking for Intelligent Transportation
Systems (ITS). The main scenarios of vehicular communications are Systems (ITS). The main scenarios of vehicular communications are
vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), and vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), and
vehicle-to-everything (V2X) communications. First, this document vehicle-to-everything (V2X) communications. First, this document
explains use cases using V2V, V2I, and V2X networking. Next, for explains use cases using V2V, V2I, and V2X networking. Next, for
IPv6-based vehicular networks, it makes a gap analysis of current IPv6-based vehicular networks, it makes a gap analysis of current
IPv6 protocols (e.g., IPv6 Neighbor Discovery, Mobility Management, IPv6 protocols (e.g., IPv6 Neighbor Discovery, Mobility Management,
and Security & Privacy), and then enumerates requirements for the and Security & Privacy), and then enumerates gaps for the extensions
extensions of those IPv6 protocols for IPv6-based vehicular of those IPv6 protocols for IPv6-based vehicular networking.
networking.
Status of This Memo Status of This Memo
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This Internet-Draft will expire on 1 October 2022. This Internet-Draft will expire on 20 November 2022.
Copyright Notice Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as extracted from this document must include Revised BSD License text as
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
skipping to change at page 2, line 19 skipping to change at page 2, line 16
and restrictions with respect to this document. Code Components and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License. provided without warranty as described in the Revised BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1. V2V . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.1. V2V . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2. V2I . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.2. V2I . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.3. V2X . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.3. V2X . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4. Vehicular Networks . . . . . . . . . . . . . . . . . . . . . 13 4. Vehicular Networks . . . . . . . . . . . . . . . . . . . . . 12
4.1. Vehicular Network Architecture . . . . . . . . . . . . . 14 4.1. Vehicular Network Architecture . . . . . . . . . . . . . 13
4.2. V2I-based Internetworking . . . . . . . . . . . . . . . . 16 4.2. V2I-based Internetworking . . . . . . . . . . . . . . . . 15
4.3. V2V-based Internetworking . . . . . . . . . . . . . . . . 19 4.3. V2V-based Internetworking . . . . . . . . . . . . . . . . 18
5. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 22 5. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 22
5.1. Neighbor Discovery . . . . . . . . . . . . . . . . . . . 23 5.1. Neighbor Discovery . . . . . . . . . . . . . . . . . . . 23
5.1.1. Link Model . . . . . . . . . . . . . . . . . . . . . 25 5.1.1. Link Model . . . . . . . . . . . . . . . . . . . . . 26
5.1.2. MAC Address Pseudonym . . . . . . . . . . . . . . . . 27 5.1.2. MAC Address Pseudonym . . . . . . . . . . . . . . . . 27
5.1.3. Routing . . . . . . . . . . . . . . . . . . . . . . . 27 5.1.3. Routing . . . . . . . . . . . . . . . . . . . . . . . 28
5.2. Mobility Management . . . . . . . . . . . . . . . . . . . 29 5.2. Mobility Management . . . . . . . . . . . . . . . . . . . 29
6. Security Considerations . . . . . . . . . . . . . . . . . . . 31 6. Security Considerations . . . . . . . . . . . . . . . . . . . 31
6.1. Security Threats in Neighbor Discovery . . . . . . . . . 32 6.1. Security Threats in Neighbor Discovery . . . . . . . . . 32
6.2. Security Threats in Mobility Management . . . . . . . . . 33 6.2. Security Threats in Mobility Management . . . . . . . . . 34
6.3. Other Threats . . . . . . . . . . . . . . . . . . . . . . 33 6.3. Other Threats . . . . . . . . . . . . . . . . . . . . . . 34
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 36
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 35 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 36
8.1. Normative References . . . . . . . . . . . . . . . . . . 35 8.1. Normative References . . . . . . . . . . . . . . . . . . 36
8.2. Informative References . . . . . . . . . . . . . . . . . 40 8.2. Informative References . . . . . . . . . . . . . . . . . 37
Appendix A. Support of Multiple Radio Technologies for V2V . . . 46 Appendix A. Support of Multiple Radio Technologies for V2V . . . 48
Appendix B. Support of Multihop V2X Networking . . . . . . . . . 46 Appendix B. Support of Multihop V2X Networking . . . . . . . . . 48
Appendix C. Support of Mobility Management for V2I . . . . . . . 48 Appendix C. Support of Mobility Management for V2I . . . . . . . 50
Appendix D. Support of MTU Diversity for IP-based Vehicular Appendix D. Support of MTU Diversity for IP-based Vehicular
Networks . . . . . . . . . . . . . . . . . . . . . . . . 49 Networks . . . . . . . . . . . . . . . . . . . . . . . . 51
Appendix E. Acknowledgments . . . . . . . . . . . . . . . . . . 50 Appendix E. Acknowledgments . . . . . . . . . . . . . . . . . . 52
Appendix F. Contributors . . . . . . . . . . . . . . . . . . . . 51 Appendix F. Contributors . . . . . . . . . . . . . . . . . . . . 53
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 52 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 54
1. Introduction 1. Introduction
Vehicular networking studies have mainly focused on improving safety Vehicular networking studies have mainly focused on improving road
and efficiency, and also enabling entertainment in vehicular safety and efficiency, and also enabling entertainment in vehicular
networks. The Federal Communications Commission (FCC) in the US networks. To proliferate the use cases of vehicular networks,
allocated wireless channels for Dedicated Short-Range Communications several governments and private organizations have committed to
(DSRC) [DSRC] in the Intelligent Transportation Systems (ITS) with allocate dedicated spectrum for vehicular communications. The
the frequency band of 5.850 - 5.925 GHz (i.e., 5.9 GHz band). DSRC- Federal Communications Commission (FCC) in the US allocated wireless
based wireless communications can support vehicle-to-vehicle (V2V), channels for Dedicated Short-Range Communications (DSRC) [DSRC] in
vehicle-to-infrastructure (V2I), and vehicle-to-everything (V2X) the Intelligent Transportation Systems (ITS) with the frequency band
networking. The European Union (EU) allocated radio spectrum for of 5.850 - 5.925 GHz (i.e., 5.9 GHz band). In November 2020, the FCC
safety-related and non-safety-related applications of ITS with the adjusted the lower 45 MHz (i.e., 5.850 - 5.895 GHz) of the 5.9 GHz
frequency band of 5.875 - 5.905 GHz, as part of the Commission band for unlicensed use instead of DSRC-dedicated use
Decision 2008/671/EC [EU-2008-671-EC]. Most countries and regions in [FCC-ITS-Modification]. DSRC-based wireless communications can
the world have adopted the same frequency allocation for vehicular support vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I),
networks. 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]. Most
other countries and regions in the world have adopted the 5.9 GHz
band for vehicular networks, though different countries use different
ways to divide the band into channels.
For direct inter-vehicular wireless connectivity, IEEE has amended For direct inter-vehicular wireless connectivity, IEEE has amended
standard 802.11 (commonly known as Wi-Fi) to enable safe driving standard 802.11 (commonly known as Wi-Fi) to enable safe driving
services based on DSRC for the Wireless Access in Vehicular services based on DSRC for the Wireless Access in Vehicular
Environments (WAVE) system. The Physical Layer (L1) and Data Link Environments (WAVE) system. The Physical Layer (L1) and Data Link
Layer (L2) issues are addressed in IEEE 802.11p [IEEE-802.11p] for 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 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 security aspects, IEEE 1609.3 [WAVE-1609.3] defines related services
at network and transport layers, and IEEE 1609.4 [WAVE-1609.4] at network and transport layers, and IEEE 1609.4 [WAVE-1609.4]
specifies the multi-channel operation. IEEE 802.11p was first a specifies the multichannel operation. IEEE 802.11p was first a
separate amendment, but was later rolled into the base 802.11 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 standard (IEEE 802.11-2012) as IEEE 802.11 Outside the Context of a
Basic Service Set (OCB) in 2012 [IEEE-802.11-OCB]. Basic Service Set (OCB) in 2012 [IEEE-802.11-OCB].
3GPP has standardized Cellular Vehicle-to-Everything (C-V2X) 3GPP has standardized Cellular Vehicle-to-Everything (C-V2X)
communications to support V2X in LTE mobile networks (called LTE 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] 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 [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 communicate with each other without relay nodes (e.g., eNodeB in LTE
and gNodeB in 5G). and gNodeB in 5G).
Along with these WAVE standards and C-V2X standards, regardless of a Along with these WAVE standards and C-V2X standards, regardless of a
wireless access technology under the IP stack of a vehicle, vehicular wireless access technology under the IP stack of a vehicle, vehicular
networks can operate IP mobility with IPv6 [RFC8200] and Mobile IPv6 networks can operate IP mobility with IPv6 [RFC8200] and Mobile IPv6
protocols (e.g., Mobile IPv6 (MIPv6) [RFC6275], Proxy MIPv6 (PMIPv6) protocols (e.g., Mobile IPv6 (MIPv6) [RFC6275], Proxy MIPv6 (PMIPv6)
[RFC5213], Distributed Mobility Management (DMM) [RFC7333], Network [RFC5213], Distributed Mobility Management (DMM) [RFC7333], Network
Mobility (NEMO) [RFC3963], Locator/ID Separation Protocol (LISP) Mobility (NEMO) [RFC3963], and Locator/ID Separation Protocol (LISP)
[I-D.ietf-lisp-rfc6830bis], and Automatic Extended Route Optimization [I-D.ietf-lisp-rfc6830bis]. In addition, ISO has approved a standard
based on the Overlay Multilink Network Interface (AERO/OMNI) specifying the IPv6 network protocols and services to be used for
[I-D.templin-6man-aero] [I-D.templin-6man-omni]). In addition, ISO Communications Access for Land Mobiles (CALM)
has approved a standard specifying the IPv6 network protocols and
services to be used for Communications Access for Land Mobiles (CALM)
[ISO-ITS-IPv6][ISO-ITS-IPv6-AMD1]. [ISO-ITS-IPv6][ISO-ITS-IPv6-AMD1].
This document describes use cases and a problem statement about This document describes use cases and a problem statement about
IPv6-based vehicular networking for ITS, which is named IPv6 Wireless IPv6-based vehicular networking for ITS, which is named IPv6 Wireless
Access in Vehicular Environments (IPWAVE). First, it introduces the Access in Vehicular Environments (IPWAVE). First, it introduces the
use cases for using V2V, V2I, and V2X networking in ITS. Next, for 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-based vehicular networks, it makes a gap analysis of current
IPv6 protocols (e.g., IPv6 Neighbor Discovery, Mobility Management, IPv6 protocols (e.g., IPv6 Neighbor Discovery, Mobility Management,
and Security & Privacy), and then enumerates requirements for the and Security & Privacy), and then enumerates gaps for the extensions
extensions of those IPv6 protocols, which are tailored to IPv6-based of those IPv6 protocols, which are tailored to IPv6-based vehicular
vehicular networking. Thus, this document is intended to motivate networking. Thus, this document is intended to motivate development
development of key protocols for IPWAVE. of key protocols for IPWAVE.
2. Terminology 2. Terminology
This document uses the terminology described in [RFC8691]. In This document uses the terminology described in [RFC8691]. In
addition, the following terms are defined below: 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 * Context-Awareness: A vehicle can be aware of spatial-temporal
mobility information (e.g., position, speed, direction, and mobility information (e.g., position, speed, direction, and
acceleration/deceleration) of surrounding vehicles for both safety acceleration/deceleration) of surrounding vehicles for both safety
and non-safety uses through sensing or communication [CASD]. and non-safety uses through sensing or communication [CASD].
* DMM: "Distributed Mobility Management" [RFC7333][RFC7429]. * 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) * Edge Computing Device (ECD): It is a computing device (or server)
for edge computing for the sake of vehicles and pedestrians. at edge for vehicles and vulnerable road users. It co-locates
with or connects to an IP-RSU, which has a powerful computing
capability for different kinds of computing tasks, such as image
processing and classification.
* Edge Network (EN): It is an access network that has an IP-RSU for * Edge Network (EN): It is an access network that has an IP-RSU for
wireless communication with other vehicles having an IP-OBU and wireless communication with other vehicles having an IP-OBU and
wired communication with other network devices (e.g., routers, IP- wired communication with other network devices (e.g., routers, IP-
RSUs, ECDs, servers, and MA). It may have a Global Positioning RSUs, ECDs, servers, and MA). It may have a global navigation
System (GPS) radio receiver for its position recognition and the satellite system (GNSS), such as Global Positioning System (GPS),
localization service for the sake of vehicles. 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 * IP-OBU: "Internet Protocol On-Board Unit": An IP-OBU denotes a
computer situated in a vehicle (e.g., car, bicycle, autobike, computer situated in a vehicle (e.g., car, bicycle, autobike,
motorcycle, and a similar one). It has at least one IP interface motorcycle, and a similar one), which has a basic processing
that runs in IEEE 802.11-OCB and has an "OBU" transceiver. Also, ability and can be driven by a low-power CPU (e.g., ARM). It has
it may have an IP interface that runs in Cellular V2X (C-V2X) at least one IP interface that runs in IEEE 802.11-OCB and has an
[TS-23.285-3GPP] [TR-22.886-3GPP][TS-23.287-3GPP]. It can play a "OBU" transceiver. Also, it may have an IP interface that runs in
role of a router connecting multiple computers (or in-vehicle Cellular V2X (C-V2X) [TS-23.285-3GPP]
devices) inside a vehicle. See the definition of the term "OBU" [TR-22.886-3GPP][TS-23.287-3GPP]. It can play the role of a
in [RFC8691]. router connecting multiple computers (or in-vehicle devices)
inside a vehicle. See the definition of the term "IP-OBU" in
[RFC8691].
* IP-RSU: "IP Roadside Unit": An IP-RSU is situated along the road. * IP-RSU: "IP Roadside Unit": An IP-RSU is situated along the road.
It has at least two distinct IP-enabled interfaces. The wireless It has at least two distinct IP-enabled interfaces. The wireless
PHY/MAC layer of at least one of its IP-enabled interfaces is 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 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 with the IP-OBU over an 802.11 wireless link operating in OCB
mode. Also, it may have the third IP-enabled wireless interface mode. Also, it may have a third IP-enabled wireless interface
running in 3GPP C-V2X in addition to the IP-RSU defined in running in 3GPP C-V2X in addition to the IP-RSU defined in
[RFC8691]. An IP-RSU is similar to an Access Network Router [RFC8691]. An IP-RSU is similar to an Access Network Router
(ANR), defined in [RFC3753], and a Wireless Termination Point (ANR), defined in [RFC3753], and a Wireless Termination Point
(WTP), defined in [RFC5415]. See the definition of the term "RSU" (WTP), defined in [RFC5415]. See the definition of the term "IP-
in [RFC8691]. RSU" in [RFC8691].
* LiDAR: "Light Detection and Ranging". It is a scanning device to * LiDAR: "Light Detection and Ranging". It is a scanning device to
measure a distance to an object by emitting pulsed laser light and measure a distance to an object by emitting pulsed laser light and
measuring the reflected pulsed light. measuring the reflected pulsed light.
* Mobility Anchor (MA): A node that maintains IPv6 addresses and * Mobility Anchor (MA): A node that maintains IPv6 addresses and
mobility information of vehicles in a road network to support mobility information of vehicles in a road network to support
their IPv6 address autoconfiguration and mobility management with their IPv6 address autoconfiguration and mobility management with
a binding table. An MA has End-to-End (E2E) connections (e.g., a binding table. An MA has End-to-End (E2E) connections (e.g.,
tunnels) with IP-RSUs under its control for the address tunnels) with IP-RSUs under its control for the address
skipping to change at page 6, line 24 skipping to change at page 6, line 14
* Traffic Control Center (TCC): A system that manages road * Traffic Control Center (TCC): A system that manages road
infrastructure nodes (e.g., IP-RSUs, MAs, traffic signals, and infrastructure nodes (e.g., IP-RSUs, MAs, traffic signals, and
loop detectors), and also maintains vehicular traffic statistics loop detectors), and also maintains vehicular traffic statistics
(e.g., average vehicle speed and vehicle inter-arrival time per (e.g., average vehicle speed and vehicle inter-arrival time per
road segment) and vehicle information (e.g., a vehicle's road segment) and vehicle information (e.g., a vehicle's
identifier, position, direction, speed, and trajectory as a identifier, position, direction, speed, and trajectory as a
navigation path). TCC is part of a vehicular cloud for vehicular navigation path). TCC is part of a vehicular cloud for vehicular
networks. networks.
* Urban Air Mobility (UAM): It refers to using lower-altitude
aircraft to transport passengers or cargo in urban and suburban
areas. The carriers used for UAM can be manned or unmanned
vehicles, which can include traditional helicopters, electrical
vertical-takeoff-and-landing aircraft (eVTOL), and unmanned aerial
vehicles (UAV).
* Vehicle: A Vehicle in this document is a node that has an IP-OBU * Vehicle: A Vehicle in this document is a node that has an IP-OBU
for wireless communication with other vehicles and IP-RSUs. It for wireless communication with other vehicles and IP-RSUs. It
has a GPS radio navigation receiver for efficient navigation. Any has a GNSS radio navigation receiver for efficient navigation.
device having an IP-OBU and a GPS receiver (e.g., smartphone and Any device having an IP-OBU and a GNSS receiver (e.g., smartphone
tablet PC) can be regarded as a vehicle in this document. and tablet PC) can be regarded as a vehicle in this document.
* Vehicular Ad Hoc Network (VANET): A network that consists of * Vehicular Ad Hoc Network (VANET): A network that consists of
vehicles interconnected by wireless communication. Two vehicles vehicles interconnected by wireless communication. Two vehicles
in a VANET can communicate with each other using other vehicles as in a VANET can communicate with each other using other vehicles as
relays even where they are out of one-hop wireless communication relays even where they are out of one-hop wireless communication
range. range.
* Vehicular Cloud: A cloud infrastructure for vehicular networks, * Vehicular Cloud: A cloud infrastructure for vehicular networks,
having compute nodes, storage nodes, and network forwarding having compute nodes, storage nodes, and network forwarding
elements (e.g., switch and router). elements (e.g., switch and router).
* V2D: "Vehicle to Device". It is the wireless communication * V2D: "Vehicle to Device". It is the wireless communication
between a vehicle and a device (e.g., smartphone and IoT device). between a vehicle and a device (e.g., smartphone and IoT device).
* V2I2D: "Vehicle to Infrastructure to Device". It is the wireless * V2P: "Vehicle to Pedestrian". It is the wireless communication
communication between a vehicle and a device (e.g., smartphone and between a vehicle and a pedestrian's device (e.g., smartphone and
IoT device) via an infrastructure node (e.g., IP-RSU). IoT device).
* V2I2V: "Vehicle to Infrastructure to Vehicle". It is the wireless * V2I2V: "Vehicle to Infrastructure to Vehicle". It is the wireless
communication between a vehicle and another vehicle via an communication between a vehicle and another vehicle via an
infrastructure node (e.g., IP-RSU). infrastructure node (e.g., IP-RSU).
* V2I2X: "Vehicle to Infrastructure to Everything". It is the * V2I2X: "Vehicle to Infrastructure to Everything". It is the
wireless communication between a vehicle and another entity (e.g., wireless communication between a vehicle and another entity (e.g.,
vehicle, smartphone, and IoT device) via an infrastructure node vehicle, smartphone, and IoT device) via an infrastructure node
(e.g., IP-RSU). (e.g., IP-RSU).
* V2X: "Vehicle to Everything". It is the wireless communication * V2X: "Vehicle to Everything". It is the wireless communication
between a vehicle and any entity (e.g., vehicle, infrastructure between a vehicle and any entity (e.g., vehicle, infrastructure
node, smartphone, and IoT device), including V2V, V2I, and V2D. 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 * VMM: "Vehicular Mobility Management". It is an IPv6-based
mobility management for vehicular networks. mobility management for vehicular networks.
* VND: "Vehicular Neighbor Discovery". It is an IPv6 ND extension * VND: "Vehicular Neighbor Discovery". It is an IPv6 ND extension
for vehicular networks. for vehicular networks.
* VSP: "Vehicular Security and Privacy". It is an IPv6-based * VSP: "Vehicular Security and Privacy". It is an IPv6-based
security and privacy term for vehicular networks. security and privacy term for vehicular networks.
* WAVE: "Wireless Access in Vehicular Environments" [WAVE-1609.0]. * WAVE: "Wireless Access in Vehicular Environments" [WAVE-1609.0].
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Management (e.g., PMIPv6 [RFC5213] and DMM [RFC7429]), and IPv6 Management (e.g., PMIPv6 [RFC5213] and DMM [RFC7429]), and IPv6
Security and Privacy Mechanisms rather than new "vehicular-specific" Security and Privacy Mechanisms rather than new "vehicular-specific"
functions. functions.
3.1. V2V 3.1. V2V
The use cases of V2V networking discussed in this section include The use cases of V2V networking discussed in this section include
* Context-aware navigation for safe driving and collision avoidance; * Context-aware navigation for safe driving and collision avoidance;
* Collision avoidance service of end systems of Urban Air Mobility
(UAM);
* Cooperative adaptive cruise control in a roadway; * Cooperative adaptive cruise control in a roadway;
* Platooning in a highway; * Platooning in a highway;
* Cooperative environment sensing; * Cooperative environment sensing.
* Collision avoidance service of end systems of Urban Air Mobility
(UAM).
These five techniques will be important elements for autonomous The above use cases are examples for using V2V networking, which can
vehicles, which may be either terrestrial vehicles or UAM end be extended to other terrestrial vehicles, river/sea ships, railed
systems. vehicles, or UAM end systems.
Context-Aware Safety Driving (CASD) navigator [CASD] can help drivers Context-Aware Safety Driving (CASD) navigator [CASD] can help drivers
to drive safely by alerting them to dangerous obstacles and to drive safely by alerting them to dangerous obstacles and
situations. That is, a CASD navigator displays obstacles or situations. That is, a CASD navigator displays obstacles or
neighboring vehicles relevant to possible collisions in real-time neighboring vehicles relevant to possible collisions in real-time
through V2V networking. CASD provides vehicles with a class-based through V2V networking. CASD provides vehicles with a class-based
automatic safety action plan, which considers three situations, automatic safety action plan, which considers three situations,
namely, the Line-of-Sight unsafe, Non-Line-of-Sight unsafe, and safe namely, the Line-of-Sight unsafe, Non-Line-of-Sight unsafe, and safe
situations. This action plan can be put into action among multiple situations. This action plan can be put into action among multiple
vehicles using V2V networking. vehicles using V2V networking.
A collision avoidance service of UAM end systems in air can be
envisioned as a use case in air vehicular environments
[I-D.templin-ipwave-uam-its]. 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.
Cooperative Adaptive Cruise Control (CACC) [CA-Cruise-Control] helps Cooperative Adaptive Cruise Control (CACC) [CA-Cruise-Control] helps
individual vehicles to adapt their speed autonomously through V2V individual vehicles to adapt their speed autonomously through V2V
communication among vehicles according to the mobility of their communication among vehicles according to the mobility of their
predecessor and successor vehicles in an urban roadway or a highway. predecessor and successor vehicles in an urban roadway or a highway.
Thus, CACC can help adjacent vehicles to efficiently adjust their Thus, CACC can help adjacent vehicles to efficiently adjust their
speed in an interactive way through V2V networking in order to avoid speed in an interactive way through V2V networking in order to avoid
a collision. a collision.
Platooning [Truck-Platooning] allows a series (or group) of vehicles Platooning [Truck-Platooning] allows a series (or group) of vehicles
(e.g., trucks) to follow each other very closely. Trucks can use V2V (e.g., trucks) to follow each other very closely. Trucks can use V2V
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Through cooperative environment sensing, driver-operated vehicles can Through cooperative environment sensing, driver-operated vehicles can
use environmental information sensed by driverless vehicles for use environmental information sensed by driverless vehicles for
better interaction with the other vehicles and environment. Vehicles better interaction with the other vehicles and environment. Vehicles
can also share their intended maneuvering information (e.g., lane can also share their intended maneuvering information (e.g., lane
change, speed change, ramp in-and-out, cut-in, and abrupt braking) change, speed change, ramp in-and-out, cut-in, and abrupt braking)
with neighboring vehicles. Thus, this information sharing can help with neighboring vehicles. Thus, this information sharing can help
the vehicles behave as more efficient traffic flows and minimize the vehicles behave as more efficient traffic flows and minimize
unnecessary acceleration and deceleration to achieve the best ride unnecessary acceleration and deceleration to achieve the best ride
comfort. comfort.
A collision avoidance service of UAM end systems in air can be
envisioned as a use case in air vehicular environments
[I-D.templin-ipwave-uam-its]. 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 To support applications of these V2V use cases, the required
functions of IPv6 include IPv6-based packet exchange and secure, safe functions of IPv6 include IPv6-based packet exchange in both control
communication between two vehicles. For the support of V2V under and data planes, and secure, safe communication between two vehicles.
multiple radio technologies (e.g., DSRC and 5G V2X), refer to For the support of V2V under multiple radio technologies (e.g., DSRC
Appendix A. and 5G V2X), refer to Appendix A.
3.2. V2I 3.2. V2I
The use cases of V2I networking discussed in this section include The use cases of V2I networking discussed in this section include
* Navigation service; * Navigation service;
* Energy-efficient speed recommendation service; * Energy-efficient speed recommendation service;
* Accident notification service; * Accident notification service;
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scheduling [SignalGuru]. For example, when a vehicle approaches an scheduling [SignalGuru]. For example, when a vehicle approaches an
intersection area and a red traffic light for the vehicle becomes intersection area and a red traffic light for the vehicle becomes
turned on, it needs to reduce its speed to save fuel consumption. In 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 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 trajectory of the vehicle and the traffic light schedule, can notify
the vehicle of an appropriate speed for fuel efficiency. the vehicle of an appropriate speed for fuel efficiency.
[Fuel-Efficient] studies fuel-efficient route and speed plans for [Fuel-Efficient] studies fuel-efficient route and speed plans for
platooned trucks. platooned trucks.
The emergency communication between accident vehicles (or emergency The emergency communication between accident vehicles (or emergency
vehicles) and a TCC can be performed via either IP-RSU or 4G-LTE vehicles) and a TCC can be performed via either IP-RSU, 4G-LTE or 5G
networks. The First Responder Network Authority (FirstNet) networks. The First Responder Network Authority (FirstNet)
[FirstNet] is provided by the US government to establish, operate, [FirstNet] is provided by the US government to establish, operate,
and maintain an interoperable public safety broadband network for and maintain an interoperable public safety broadband network for
safety and security network services, e.g., emergency calls. The safety and security network services, e.g., emergency calls. The
construction of the nationwide FirstNet network requires each state construction of the nationwide FirstNet network requires each state
in the US to have a Radio Access Network (RAN) that will connect to 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 the FirstNet's network core. The current RAN is mainly constructed
using 4G-LTE for the communication between a vehicle and an using 4G-LTE for the communication between a vehicle and an
infrastructure node (i.e., V2I) [FirstNet-Report], but it is expected infrastructure node (i.e., V2I) [FirstNet-Report], but it is expected
that DSRC-based vehicular networks [DSRC] will be available for V2I that DSRC-based vehicular networks [DSRC] will be available for V2I
and V2V in the near future. An equivalent project in Europe is and V2V in the near future. An equivalent project in Europe is
called Public Safety Communications Europe (PSCE) [PSCE], which is called Public Safety Communications Europe (PSCE) [PSCE], which is
developing a network for emergency communications. developing a network for emergency communications.
An EV charging service with V2I can facilitate the efficient battery An EV charging service with V2I can facilitate the efficient battery
charging of EVs. In the case where an EV charging station is 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 connected to an IP-RSU, an EV can be guided toward the deck of the EV
charging station or be notified that the charging station is out of charging station or be notified that the charging station is out of
service through a battery charging server connected to the IP-RSU. service through a battery charging server connected to the IP-RSU.
In addition to this EV charging service, other value-added services In addition to this EV charging service, other value-added services
(e.g., air firmware/software update and media streaming) can be (e.g., firmware/software update over-the-air and media streaming) can
provided to an EV while it is charging its battery at the EV charging be provided to an EV while it is charging its battery at the EV
station. charging station. For a UAM navigation service, an efficient battery
charging plan can improve the battery charging schedule of UAM end
A UAM navigation service with efficient battery charging can plan the systems (e.g., drone) for long-distance flying [CBDN]. For this
battery charging schedule of UAM end systems (e.g., drone) for long- battery charging schedule, a UAM end system can communicate with a
distance flying [CBDN]. For this battery charging schedule, a UAM cloud server via an infrastructure node (e.g., IP-RSU). This cloud
end system can communicate with an infrastructure node (e.g., IP-RSU) server can coordinate the battery charging schedules of multiple UAM
toward a cloud server via V2I communications. This cloud server can end systems for their efficient navigation path, considering flight
coordinate the battery charging schedules of multiple UAM end systems time from their current position to a battery charging station,
for their efficient navigation path, considering flight time from waiting time in a waiting queue at the station, and battery charging
their current position to a battery charging station, waiting time in time at the station.
a waiting queue at the station, and battery charging time at the
station.
In some scenarios such as vehicles moving in highways or staying in In some scenarios such as vehicles moving in highways or staying in
parking lots, a V2V2I network is necessary for vehicles to access the parking lots, a V2V2I network is necessary for vehicles to access the
Internet since some vehicles may not be covered by an RSU. For those Internet since some vehicles may not be covered by an IP-RSU. For
vehicles, a few relay vehicles can help to build the Internet access. those vehicles, a few relay vehicles can help to build the Internet
For the nested NEMO described in [RFC4888], hosts inside a vehicle access. For the nested NEMO described in [RFC4888], hosts inside a
shown in Figure 3 for the case of V2V2I may have the same issue in vehicle shown in Figure 3 for the case of V2V2I may have the same
the nested NEMO scenario. issue in the nested NEMO scenario.
To better support these use cases, the existing IPv6 protocol must be To better support these use cases, the existing IPv6 protocol must be
augmented either through protocol changes or by including a new augmented either through protocol changes or by including a new
adaptation layer in the architecture that efficiently maps IPv6 to a adaptation layer in the architecture that efficiently maps IPv6 to a
diversity of link layer technologies. Augmentation is necessary to diversity of link layer technologies. Augmentation is necessary to
support wireless multihop V2I communications in a highway where RSUs support wireless multihop V2I communications in a highway where RSUs
are sparsely deployed, so a vehicle can reach the wireless coverage are sparsely deployed, so a vehicle can reach the wireless coverage
of an RSU through the multihop data forwarding of intermediate of an IP-RSU through the multihop data forwarding of intermediate
vehicles as packet forwarders. Thus, IPv6 needs to be extended for vehicles as packet forwarders. Thus, IPv6 needs to be extended for
multihop V2I communications. multihop V2I communications.
To support applications of these V2I use cases, the required To support applications of these V2I use cases, the required
functions of IPv6 include IPv6 communication enablement with functions of IPv6 include IPv6 communication enablement with
neighborhood discovery and IPv6 address management, reachability with neighborhood discovery and IPv6 address management, reachability with
adapted network models and routing methods, transport-layer session adapted network models and routing methods, transport-layer session
continuity, and secure, safe communication between a vehicle and an continuity, and secure, safe communication between a vehicle and an
infrastructure node (e.g., IP-RSU) in the vehicular network. infrastructure node (e.g., IP-RSU) in the vehicular network.
3.3. V2X 3.3. V2X
The use case of V2X networking discussed in this section is for a The use case of V2X networking discussed in this section is for a
pedestrian protection service. vulnerable road user (VRU) (e.g., pedestrian and cyclist) protection
service. Note that the application area of this use case is
currently limited to a specific environment, such as construction
sites, plants, and factories, since not every VRU (e.g., children) in
a public area (e.g., streets) is equipped with a smart device (e.g.,
smartphone).
A pedestrian protection service, such as Safety-Aware Navigation A VRU protection service, such as Safety-Aware Navigation Application
Application (SANA) [SANA], using V2I2P networking can reduce the (SANA) [SANA], using V2I2P networking can reduce the collision of a
collision of a vehicle and a pedestrian carrying a smartphone vehicle and a pedestrian carrying a smartphone equipped with a
equipped with a network device for wireless communication (e.g., Wi- network device for wireless communication (e.g., Wi-Fi, DSRC, 4G/5G
Fi) with an IP-RSU. Vehicles and pedestrians can also communicate V2X, and BLE) with an IP-RSU. Vehicles and pedestrians can also
with each other via an IP-RSU. An edge computing device behind the communicate with each other via an IP-RSU. An edge computing device
IP-RSU can collect the mobility information from vehicles and behind the IP-RSU can collect the mobility information from vehicles
pedestrians, compute wireless communication scheduling for the sake and pedestrians, compute wireless communication scheduling for the
of them. This scheduling can save the battery of each pedestrian's sake of them. This scheduling can save the battery of each
smartphone by allowing it to work in sleeping mode before the pedestrian's smartphone by allowing it to work in sleeping mode
communication with vehicles, considering their mobility. before the communication with vehicles, considering their mobility.
The location information of a VRU from a smart device is multicasted
only to the nearby vehicles. The true identifiers of a VRU's
smartphone shall be protected, and only the type of the VRU, such as
pedestrian, cyclist, and scooter, is disclosed to the nearby
vehicles.
For Vehicle-to-Pedestrian (V2P), a vehicle can directly communicate For Vehicle-to-Pedestrian (V2P), a vehicle can directly communicate
with a pedestrian's smartphone by V2X without IP-RSU relaying. with a pedestrian's smartphone by V2X without IP-RSU relaying.
Light-weight mobile nodes such as bicycles may also communicate Light-weight mobile nodes such as bicycles may also communicate
directly with a vehicle for collision avoidance using V2V. Note that directly with a vehicle for collision avoidance using V2V. Note that
it is true that a pedestrian or a cyclist may have a higher risk of it is true that either a pedestrian or a cyclist may have a higher
being hit by a vehicle if they are not with a smartphone in the risk of being hit by a vehicle if they are not with a smartphone in
current setting. For this case, other human sensing technologies the current setting. For this case, other human sensing technologies
(e.g., moving object detection in images and wireless signal-based (e.g., moving object detection in images and wireless signal-based
human movement detection [LIFS] [DFC]) can be used to provide the human movement detection [LIFS] [DFC]) can be used to provide the
motion information of them to vehicles. A vehicle by V2V2I motion information of them to vehicles. A vehicle by V2V2I
networking can obtain the motion information of a vulnerable road networking can obtain the motion information of a VRU via an IP-RSU
user via an IP-RSU that either employs or connects to a human sensing that either employs or connects to a human sensing technology.
technology.
The existing IPv6 protocol must be augmented through protocol changes The existing IPv6 protocol must be augmented through protocol changes
in order to support wireless multihop V2X or V2I2X communications in in order to support wireless multihop V2X or V2I2X communications in
an urban road network where RSUs are deployed at intersections, so a an urban road network where RSUs are deployed at intersections, so a
vehicle (or a pedestrian's smartphone) can reach the wireless vehicle (or a pedestrian's smartphone) can reach the wireless
coverage of an RSU through the multihop data forwarding of coverage of an IP-RSU through the multihop data forwarding of
intermediate vehicles (or pedestrians' smartphones) as packet intermediate vehicles (or pedestrians' smartphones) as packet
forwarders. Thus, IPv6 needs to be extended for multihop V2X or forwarders. Thus, IPv6 needs to be extended for multihop V2X or
V2I2X communications. V2I2X communications.
To support applications of these V2X use cases, the required To support applications of these V2X use cases, the required
functions of IPv6 include IPv6-based packet exchange, transport-layer functions of IPv6 include IPv6-based packet exchange, transport-layer
session continuity, and secure, safe communication between a vehicle session continuity, and secure, safe communication between a vehicle
and a pedestrian either directly or indirectly via an IP-RSU. and a pedestrian either directly or indirectly via an IP-RSU.
4. Vehicular Networks 4. Vehicular Networks
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vehicular networks according to target use cases in Section 3. vehicular networks according to target use cases in Section 3.
Existing network architectures, such as the network architectures of Existing network architectures, such as the network architectures of
PMIPv6 [RFC5213], RPL (IPv6 Routing Protocol for Low-Power and Lossy PMIPv6 [RFC5213], RPL (IPv6 Routing Protocol for Low-Power and Lossy
Networks) [RFC6550], and AERO/OMNI Networks) [RFC6550], and AERO/OMNI
[I-D.templin-6man-aero][I-D.templin-6man-omni], can be extended to a [I-D.templin-6man-aero][I-D.templin-6man-omni], can be extended to a
vehicular network architecture for multihop V2V, V2I, and V2X, as vehicular network architecture for multihop V2V, V2I, and V2X, as
shown in Figure 1. Refer to Appendix B for the detailed discussion shown in Figure 1. Refer to Appendix B for the detailed discussion
on multihop V2X networking by RPL and OMNI. Also, refer to on multihop V2X networking by RPL and OMNI. Also, refer to
Appendix A for the description of how OMNI is designed to support the Appendix A for the description of how OMNI is designed to support the
use of multiple radio technologies in V2X. use of multiple radio technologies in V2X. Note that though AERO/
OMNI is not actually deployed in the industry, this AERO/OMNI is
As shown in this figure, IP-RSUs as routers and vehicles with IP-OBU mentioned as a possible approach for vehicular networks in this
have wireless media interfaces for VANET. Furthermore, the wireless document.
media interfaces are autoconfigured with a global IPv6 prefix (e.g.,
2001:DB8:1:1::/64) to support both V2V and V2I networking.
In Figure 1, three IP-RSUs (IP-RSU1, IP-RSU2, and IP-RSU3) are As shown in Figure 1, IP-RSUs as routers and vehicles with IP-OBU
deployed in the road network and are connected with each other have wireless media interfaces for VANET. The three IP-RSUs (IP-
through the wired networks (e.g., Ethernet). A Traffic Control RSU1, IP-RSU2, and IP-RSU3) are deployed in the road network and are
Center (TCC) is connected to the Vehicular Cloud for the management connected with each other through the wired networks (e.g.,
of IP-RSUs and vehicles in the road network. A Mobility Anchor (MA) Ethernet). A Traffic Control Center (TCC) is connected to the
may be located in the TCC as a mobility management controller. Vehicular Cloud for the management of IP-RSUs and vehicles in the
Vehicle2, Vehicle3, and Vehicle4 are wirelessly connected to IP-RSU1, road network. A Mobility Anchor (MA) may be located in the TCC as a
IP-RSU2, and IP-RSU3, respectively. The three wireless networks of mobility management controller. Vehicle2, Vehicle3, and Vehicle4 are
IP-RSU1, IP-RSU2, and IP-RSU3 can belong to three different subnets wirelessly connected to IP-RSU1, IP-RSU2, and IP-RSU3, respectively.
(i.e., Subnet1, Subnet2, and Subnet3), respectively. Those three The three wireless networks of IP-RSU1, IP-RSU2, and IP-RSU3 can
subnets use three different prefixes (i.e., Prefix1, Prefix2, and belong to three different subnets (i.e., Subnet1, Subnet2, and
Prefix3). 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 Multiple vehicles under the coverage of an IP-RSU share a prefix just
mobile nodes share a prefix of a Wi-Fi access point in a wireless as mobile nodes share a prefix of a Wi-Fi access point in a wireless
LAN. This is a natural characteristic in infrastructure-based LAN. This is a natural characteristic in infrastructure-based
wireless networks. For example, in Figure 1, two vehicles (i.e., wireless networks. For example, in Figure 1, two vehicles (i.e.,
Vehicle2, and Vehicle5) can use Prefix 1 to configure their IPv6 Vehicle2, and Vehicle5) can use Prefix 1 to configure their IPv6
global addresses for V2I communication. Alternatively, mobile nodes global addresses for V2I communication. Alternatively, mobile nodes
can employ a "Bring-Your-Own-Addresses (BYOA)" (or "Bring-Your-Own- can employ a "Bring-Your-Own-Addresses (BYOA)" (or "Bring-Your-Own-
Prefix (BYOP)") technique using their own IPv6 Unique Local Addresses Prefix (BYOP)") technique using their own IPv6 Unique Local Addresses
(ULAs) [RFC4193] over the wireless network, which does not require (ULAs) [RFC4193] over the wireless network.
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 wireless subnets in vehicular networks (e.g., Subnet1 and Subnet2
in Figure 1), vehicles can construct a connected VANET (with an in Figure 1), vehicles can construct a connected VANET (with an
arbitrary graph topology) and can communicate with each other via V2V arbitrary graph topology) and can communicate with each other via V2V
communication. Vehicle1 can communicate with Vehicle2 via V2V communication. Vehicle1 can communicate with Vehicle2 via V2V
communication, and Vehicle2 can communicate with Vehicle3 via V2V communication, and Vehicle2 can communicate with Vehicle3 via V2V
communication because they are within the wireless communication communication because they are within the wireless communication
range of each other. On the other hand, Vehicle3 can communicate range of each other. On the other hand, Vehicle3 can communicate
with Vehicle4 via the vehicular infrastructure (i.e., IP-RSU2 and IP- with Vehicle4 via the vehicular infrastructure (i.e., IP-RSU2 and IP-
RSU3) by employing V2I (i.e., V2I2V) communication because they are RSU3) by employing V2I (i.e., V2I2V) communication because they are
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communication continuity in vehicular networks so that a vehicle's communication continuity in vehicular networks so that a vehicle's
TCP session can be continued, or UDP packets can be delivered to a 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 vehicle as a destination without loss while it moves from an IP-RSU's
wireless coverage to another IP-RSU's wireless coverage. In wireless coverage to another IP-RSU's wireless coverage. In
Figure 1, assuming that Vehicle2 has a TCP session (or a UDP session) Figure 1, assuming that Vehicle2 has a TCP session (or a UDP session)
with a correspondent node in the vehicular cloud, Vehicle2 can move with a correspondent node in the vehicular cloud, Vehicle2 can move
from IP-RSU1's wireless coverage to IP-RSU2's wireless coverage. In 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 this case, a handover for Vehicle2 needs to be performed by either a
host-based mobility management scheme (e.g., MIPv6 [RFC6275]) or a host-based mobility management scheme (e.g., MIPv6 [RFC6275]) or a
network-based mobility management scheme (e.g., PMIPv6 [RFC5213], network-based mobility management scheme (e.g., PMIPv6 [RFC5213],
NEMO [RFC3963][RFC4885] [RFC4888], and AERO [I-D.templin-6man-aero]). NEMO [RFC3963] [RFC4885] [RFC4888], and AERO
This document describes issues in mobility management for vehicular [I-D.templin-6man-aero]). This document describes issues in mobility
networks in Section 5.2. management for vehicular networks in Section 5.2. For improving TCP
session continuity or successful UDP packet delivery, the multi-path
TCP (MPTCP) [RFC8684] or QUIC protocol [RFC9000] can also be used.
IP-OBUs, however, may still experience more session time-out and re-
establishment procedures due to lossy connections among vehicles
caused by the high mobility dynamics of them.
4.2. V2I-based Internetworking 4.2. V2I-based Internetworking
This section discusses the internetworking between a vehicle's This section discusses the internetworking between a vehicle's
internal network (i.e., mobile network) and an EN's internal network internal network (i.e., mobile network) and an EN's internal network
(i.e., fixed network) via V2I communication. The internal network of (i.e., fixed network) via V2I communication. The internal network of
a vehicle is nowadays constructed with Ethernet by many automotive a vehicle is nowadays constructed with Ethernet by many automotive
vendors [In-Car-Network]. Note that an EN can accommodate multiple vendors [In-Car-Network]. Note that an EN can accommodate multiple
routers (or switches) and servers (e.g., ECDs, navigation server, and routers (or switches) and servers (e.g., ECDs, navigation server, and
DNS server) in its internal network. DNS server) in its internal network.
A vehicle's internal network often uses Ethernet to interconnect A vehicle's internal network often uses Ethernet to interconnect
Electronic Control Units (ECUs) in the vehicle. The internal network Electronic Control Units (ECUs) in the vehicle. The internal network
can support Wi-Fi and Bluetooth to accommodate a driver's and can support Wi-Fi and Bluetooth to accommodate a driver's and
passenger's mobile devices (e.g., smartphone or tablet). The network passenger's mobile devices (e.g., smartphone or tablet). The network
topology and subnetting depend on each vendor's network configuration topology and subnetting depend on each vendor's network configuration
for a vehicle and an EN. It is reasonable to consider the for a vehicle and an EN. It is reasonable to consider interactions
interaction between the internal network and an external network between the internal network of a vehicle and that of another vehicle
within another vehicle or an EN. Note that it is dangerous if the or an EN. Note that it is dangerous if the internal network of a
internal network of a vehicle is controlled by a malicious party. To vehicle is controlled by a malicious party. These dangers can
minimize this kind of risk, an reinforced identification and include unauthorized driving control input and unauthorized driving
verification protocol shall be implemented. information disclosure to an unauthorized third party. A malicious
party can be a group of hackers, a criminal group, and a competitor
for industrial espionage or sabotage. To minimize this kind of risk,
an augmented identification and verification protocol with extra
means shall be implemented. These extra means can be certificate-
based, biometric, credit-based, and one-time passcode (OTP)
approaches in addition to a used approach [RFC8002]. The
verification shall provide security properties such as
confidentiality, integrity, authentication, authorization, and
accounting [RFC7427].
+-----------------+ +-----------------+
(*)<........>(*) +----->| Vehicular Cloud | (*)<........>(*) +----->| Vehicular Cloud |
(2001:DB8:1:1::/64) | | | +-----------------+ (2001:db8:1:1::/64) | | | +-----------------+
+------------------------------+ +---------------------------------+ +------------------------------+ +---------------------------------+
| v | | v v | | v | | v v |
| +-------+ +-------+ | | +-------+ +-------+ | | +-------+ +-------+ | | +-------+ +-------+ |
| | Host1 | |IP-OBU1| | | |IP-RSU1| | Host3 | | | | Host1 | |IP-OBU1| | | |IP-RSU1| | Host3 | |
| +-------+ +-------+ | | +-------+ +-------+ | | +-------+ +-------+ | | +-------+ +-------+ |
| ^ ^ | | ^ ^ | | ^ ^ | | ^ ^ |
| | | | | | | | | | | | | | | |
| v v | | v v | | v v | | v v |
| ---------------------------- | | ------------------------------- | | ---------------------------- | | ------------------------------- |
| 2001:DB8:10:1::/64 ^ | | ^ 2001:DB8:20:1::/64 | | 2001:db8:10:1::/64 ^ | | ^ 2001:db8:20:1::/64 |
| | | | | | | | | | | |
| v | | v | | v | | v |
| +-------+ +-------+ | | +-------+ +-------+ +-------+ | | +-------+ +-------+ | | +-------+ +-------+ +-------+ |
| | Host2 | |Router1| | | |Router2| |Server1|...|ServerN| | | | Host2 | |Router1| | | |Router2| |Server1|...|ServerN| |
| +-------+ +-------+ | | +-------+ +-------+ +-------+ | | +-------+ +-------+ | | +-------+ +-------+ +-------+ |
| ^ ^ | | ^ ^ ^ | | ^ ^ | | ^ ^ ^ |
| | | | | | | | | | | | | | | | | |
| v v | | v v v | | v v | | v v v |
| ---------------------------- | | ------------------------------- | | ---------------------------- | | ------------------------------- |
| 2001:DB8:10:2::/64 | | 2001:DB8:20:2::/64 | | 2001:db8:10:2::/64 | | 2001:db8:20:2::/64 |
+------------------------------+ +---------------------------------+ +------------------------------+ +---------------------------------+
Vehicle1 (Mobile Network1) EN1 (Fixed Network1) Vehicle1 (Mobile Network1) EN1 (Fixed Network1)
<----> Wired Link <....> Wireless Link (*) Antenna <----> Wired Link <....> Wireless Link (*) Antenna
Figure 2: Internetworking between Vehicle and Edge Network Figure 2: Internetworking between Vehicle and Edge Network
As shown in Figure 2, as internal networks, a vehicle's mobile As shown in Figure 2, as internal networks, a vehicle's mobile
network and an EN's fixed network are self-contained networks having 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) multiple subnets and having an edge router (e.g., IP-OBU and IP-RSU)
for the communication with another vehicle or another EN. The for the communication with another vehicle or another EN. The
internetworking between two internal networks via V2I communication internetworking between two internal networks via V2I communication
requires the exchange of the network parameters and the network 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. For the efficiency, the network
prefixes of the internal networks (as a mobile network) in a vehicle prefixes of the internal networks (as a mobile network) in a vehicle
skipping to change at page 18, line 7 skipping to change at page 17, line 27
Figure 2 also shows the internetworking between the vehicle's mobile Figure 2 also shows the internetworking between the vehicle's mobile
network and the EN's fixed network. There exists an internal network network and the EN's fixed network. There exists an internal network
(Mobile Network1) inside Vehicle1. Vehicle1 has two hosts (Host1 and (Mobile Network1) inside Vehicle1. Vehicle1 has two hosts (Host1 and
Host2), and two routers (IP-OBU1 and Router1). There exists another Host2), and two routers (IP-OBU1 and Router1). There exists another
internal network (Fixed Network1) inside EN1. EN1 has one host internal network (Fixed Network1) inside EN1. EN1 has one host
(Host3), two routers (IP-RSU1 and Router2), and the collection of (Host3), two routers (IP-RSU1 and Router2), and the collection of
servers (Server1 to ServerN) for various services in the road servers (Server1 to ServerN) for various services in the road
networks, such as the emergency notification and navigation. networks, such as the emergency notification and navigation.
Vehicle1's IP-OBU1 (as a mobile router) and EN1's IP-RSU1 (as a fixed 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 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 V2I networking. Thus, a host (Host1) in Vehicle1 can communicate
with a server (Server1) in EN1 for a vehicular service through with a server (Server1) in EN1 for a vehicular service through
Vehicle1's moving network, a wireless link between IP-OBU1 and IP- Vehicle1's moving network, a wireless link between IP-OBU1 and IP-
RSU1, and EN1's fixed network. RSU1, and EN1's fixed network.
For the IPv6 communication between an IP-OBU and an IP-RSU or between 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, two neighboring IP-OBUs, they need to know the network parameters,
which include MAC layer and IPv6 layer information. The MAC layer which include MAC layer and IPv6 layer information. The MAC layer
information includes wireless link layer parameters, transmission information includes wireless link layer parameters, transmission
power level, and the MAC address of an external network interface for power level, and the MAC address of an external network interface for
the internetworking with another IP-OBU or IP-RSU. The IPv6 layer the internetworking with another IP-OBU or IP-RSU. The IPv6 layer
information includes the IPv6 address and network prefix of an information includes the IPv6 address and network prefix of an
external network interface for the internetworking with another IP- external network interface for the internetworking with another IP-
OBU or IP-RSU. OBU or IP-RSU.
Through the mutual knowledge of the network parameters of internal Through the mutual knowledge of the network parameters of internal
networks, packets can be transmitted between the vehicle's moving networks, packets can be transmitted between the vehicle's moving
network and the EN's fixed network. Thus, V2I requires an efficient network and the EN's fixed network. Thus, V2I requires an efficient
protocol for the mutual knowledge of network parameters. protocol for the mutual knowledge of network parameters. Note that
from a security point of view, a perimeter-based policy enforcement
can be applied to protect parts of the internal network of a vehicle.
As shown in Figure 2, the addresses used for IPv6 transmissions over 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 the wireless link interfaces for IP-OBU and IP-RSU can be link-local
IPv6 addresses, ULAs, or global IPv6 addresses. When global IPv6 IPv6 addresses, ULAs, or global IPv6 addresses. When IPv6 addresses
addresses are used, wireless interface configuration and control are used, wireless interface configuration and control overhead for
overhead for DAD [RFC4862] and Multicast Listener Discovery (MLD) DAD [RFC4862] and Multicast Listener Discovery (MLD)
[RFC2710][RFC3810] should be minimized to support V2I and V2X [RFC2710][RFC3810] should be minimized to support V2I and V2X
communications for vehicles moving fast along roadways. communications for vehicles moving fast along roadways.
Let us consider the upload/download time of a ground vehicle when it Let us consider the upload/download time of a ground vehicle when it
passes through the wireless communication coverage of an IP-RSU. For passes through the wireless communication coverage of an IP-RSU. For
a given typical setting where 1km is the maximum DSRC communication a given typical setting where 1km is the maximum DSRC communication
range [DSRC] and 100km/h is the speed limit in highway for ground range [DSRC] and 100km/h is the speed limit in highway for ground
vehicles, the dwelling time can be calculated to be 72 seconds by vehicles, the dwelling time can be calculated to be 72 seconds by
dividing the diameter of the 2km (i.e., two times of DSRC 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 communication range where an IP-RSU is located in the center of the
skipping to change at page 19, line 11 skipping to change at page 19, line 6
that of other vehicles. For cases of airborne vehicles, considering that of other vehicles. For cases of airborne vehicles, considering
a higher flying speed and a higher altitude, the dwelling time can be a higher flying speed and a higher altitude, the dwelling time can be
much shorter. much shorter.
4.3. V2V-based Internetworking 4.3. V2V-based Internetworking
This section discusses the internetworking between the moving This section discusses the internetworking between the moving
networks of two neighboring vehicles via V2V communication. networks of two neighboring vehicles via V2V communication.
(*)<..........>(*) (*)<..........>(*)
(2001:DB8:1:1::/64) | | (2001:db8:1:1::/64) | |
+------------------------------+ +------------------------------+ +------------------------------+ +------------------------------+
| v | | v | | v | | v |
| +-------+ +-------+ | | +-------+ +-------+ | | +-------+ +-------+ | | +-------+ +-------+ |
| | Host1 | |IP-OBU1| | | |IP-OBU2| | Host3 | | | | Host1 | |IP-OBU1| | | |IP-OBU2| | Host3 | |
| +-------+ +-------+ | | +-------+ +-------+ | | +-------+ +-------+ | | +-------+ +-------+ |
| ^ ^ | | ^ ^ | | ^ ^ | | ^ ^ |
| | | | | | | | | | | | | | | |
| v v | | v v | | v v | | v v |
| ---------------------------- | | ---------------------------- | | ---------------------------- | | ---------------------------- |
| 2001:DB8:10:1::/64 ^ | | ^ 2001:DB8:30:1::/64 | | 2001:db8:10:1::/64 ^ | | ^ 2001:db8:30:1::/64 |
| | | | | | | | | | | |
| v | | v | | v | | v |
| +-------+ +-------+ | | +-------+ +-------+ | | +-------+ +-------+ | | +-------+ +-------+ |
| | Host2 | |Router1| | | |Router2| | Host4 | | | | Host2 | |Router1| | | |Router2| | Host4 | |
| +-------+ +-------+ | | +-------+ +-------+ | | +-------+ +-------+ | | +-------+ +-------+ |
| ^ ^ | | ^ ^ | | ^ ^ | | ^ ^ |
| | | | | | | | | | | | | | | |
| v v | | v v | | v v | | v v |
| ---------------------------- | | ---------------------------- | | ---------------------------- | | ---------------------------- |
| 2001:DB8:10:2::/64 | | 2001:DB8:30:2::/64 | | 2001:db8:10:2::/64 | | 2001:db8:30:2::/64 |
+------------------------------+ +------------------------------+ +------------------------------+ +------------------------------+
Vehicle1 (Mobile Network1) Vehicle2 (Mobile Network2) Vehicle1 (Mobile Network1) Vehicle2 (Mobile Network2)
<----> Wired Link <....> Wireless Link (*) Antenna <----> Wired Link <....> Wireless Link (*) Antenna
Figure 3: Internetworking between Two Vehicles Figure 3: Internetworking between Two Vehicles
Figure 3 shows the internetworking between the mobile networks of two Figure 3 shows the internetworking between the mobile networks of two
neighboring vehicles. There exists an internal network (Mobile neighboring vehicles. There exists an internal network (Mobile
Network1) inside Vehicle1. Vehicle1 has two hosts (Host1 and Host2), Network1) inside Vehicle1. Vehicle1 has two hosts (Host1 and Host2),
and two routers (IP-OBU1 and Router1). There exists another internal and two routers (IP-OBU1 and Router1). There exists another internal
network (Mobile Network2) inside Vehicle2. Vehicle2 has two hosts network (Mobile Network2) inside Vehicle2. Vehicle2 has two hosts
(Host3 and Host4), and two routers (IP-OBU2 and Router2). Vehicle1's (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 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 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 V2V networking. Thus, a host (Host1) in Vehicle1 can communicate
with another host (Host3) in Vehicle2 for a vehicular service through with another host (Host3) in Vehicle2 for a vehicular service through
Vehicle1's mobile network, a wireless link between IP-OBU1 and IP- Vehicle1's mobile network, a wireless link between IP-OBU1 and IP-
OBU2, and Vehicle2's mobile network. OBU2, and Vehicle2's mobile network.
As a V2V use case in Section 3.1, Figure 4 shows the linear 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 topology of platooning vehicles for V2V communications where Vehicle3
is the leading vehicle with a driver, and Vehicle2 and Vehicle1 are is the leading vehicle with a driver, and Vehicle2 and Vehicle1 are
the following vehicles without drivers. the following vehicles without drivers. From a security point of
view, before vehicles can be platooned, they shall be mutually
authenticated to reduce possible security risks.
(*)<..................>(*)<..................>(*) (*)<..................>(*)<..................>(*)
| | | | | |
+-----------+ +-----------+ +-----------+ +-----------+ +-----------+ +-----------+
| | | | | | | | | | | |
| +-------+ | | +-------+ | | +-------+ | | +-------+ | | +-------+ | | +-------+ |
| |IP-OBU1| | | |IP-OBU2| | | |IP-OBU3| | | |IP-OBU1| | | |IP-OBU2| | | |IP-OBU3| |
| +-------+ | | +-------+ | | +-------+ | | +-------+ | | +-------+ | | +-------+ |
| ^ | | ^ | | ^ | | ^ | | ^ | | ^ |
| | |=====> | | |=====> | | |=====> | | |=====> | | |=====> | | |=====>
skipping to change at page 22, line 16 skipping to change at page 22, line 16
than freely moving vehicles, as described in Section 3.1. than freely moving vehicles, as described in Section 3.1.
5. Problem Statement 5. Problem Statement
In order to specify protocols using the architecture mentioned in In order to specify protocols using the architecture mentioned in
Section 4.1, IPv6 core protocols have to be adapted to overcome Section 4.1, IPv6 core protocols have to be adapted to overcome
certain challenging aspects of vehicular networking. Since the certain challenging aspects of vehicular networking. Since the
vehicles are likely to be moving at great speed, protocol exchanges vehicles are likely to be moving at great speed, protocol exchanges
need to be completed in a relatively short time compared to the need to be completed in a relatively short time compared to the
lifetime of a link between a vehicle and an IP-RSU, or between two lifetime of a link between a vehicle and an IP-RSU, or between two
vehicles. vehicles. In these cases, vehicles may not have enough time either
to build link-layer connections with each other and may rely more on
connections with infrastructure. In other cases, the relative speed
between vehicles may be low when vehicles move toward the same
direction or are platooned. For those cases, vehicles can have more
time to build and maintain connections with each other.
For safe driving, vehicles need to exchange application messages For safe driving, vehicles need to exchange application messages
every 0.5 second [NHTSA-ACAS-Report] to let drivers take an action to every 0.5 second [NHTSA-ACAS-Report] to let drivers take an action to
avoid a dangerous situation (e.g., vehicle collision), so IPv6 avoid a dangerous situation (e.g., vehicle collision), so the IPv6
protocol exchanges need to support this order of magnitude for control plane (e.g., ND procedure and DAD) needs to support this
application message exchanges. Also, considering the communication order of magnitude for application message exchanges. Also,
range of DSRC (up to 1km) and 100km/h as the speed limit in highway, considering the communication range of DSRC (up to 1km) and 100km/h
the lifetime of a link between a vehicle and an IP-RSU is in the as the speed limit in highway (some countries can have much higher
order of a minute (e.g., about 72 seconds), and the lifetime of a speed limit or even no limit, e.g., Germany), the lifetime of a link
link between two vehicles is about a half minute. Note that if two between a vehicle and an IP-RSU is in the order of a minute (e.g.,
vehicles are moving in the opposite directions in a roadway, the about 72 seconds), and the lifetime of a link between two vehicles is
relative speed of this case is two times the relative speed of a about a half minute. Note that if two vehicles are moving in the
vehicle passing through an RSU. This relative speed leads the half opposite directions in a roadway, the relative speed of this case is
of the link lifetime between the vehicle and the IP-RSU. In reality, two times the relative speed of a vehicle passing through an IP-RSU.
the DSRC communication range is around 500m, so the link lifetime This relative speed leads the half of the link lifetime between the
will be a half of the maximum time. The time constraint of a vehicle and the IP-RSU. In reality, the DSRC communication range is
wireless link between two nodes (e.g., vehicle and IP-RSU) needs to around 500m, so the link lifetime will be a half of the maximum time.
be considered because it may affect the lifetime of a session The time constraint of a wireless link between two nodes (e.g.,
involving the link. The lifetime of a session varies depending on vehicle and IP-RSU) needs to be considered because it may affect the
the session's type such as a web surfing, voice call over IP, DNS lifetime of a session involving the link. The lifetime of a session
query, and context-aware navigation (in Section 3.1). Regardless of varies depending on the session's type such as a web surfing, voice
a session's type, to guide all the IPv6 packets to their destination call over IP, DNS query, and context-aware navigation (in
host(s), IP mobility should be supported for the session. In a V2V Section 3.1). Regardless of a session's type, to guide all the IPv6
scenario (e.g., context-aware navigation), the IPv6 packets of a packets to their destination host(s), IP mobility should be supported
vehicle should be delivered to relevant vehicles in an efficient way for the session. In a V2V scenario (e.g., context-aware navigation),
(e.g., multicasting). With this observation, IPv6 protocol exchanges the IPv6 packets of a vehicle should be delivered to relevant
need to be done as short as possible to support the message exchanges vehicles efficiently (e.g., multicasting). With this observation,
of various applications in vehicular networks. 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 Therefore, the time constraint of a wireless link has a major impact
on IPv6 Neighbor Discovery (ND). Mobility Management (MM) is also on IPv6 Neighbor Discovery (ND). Mobility Management (MM) is also
vulnerable to disconnections that occur before the completion of vulnerable to disconnections that occur before the completion of
identity verification and tunnel management. This is especially true identity verification and tunnel management. This is especially true
given the unreliable nature of wireless communication. Meanwhile, given the unreliable nature of wireless communication. Meanwhile,
the bandwidth of the wireless link determined by the lower layers the bandwidth of the wireless link determined by the lower layers
(i.e., link and PHY layers) can affect the transmission time of (i.e., link and PHY layers) can affect the transmission time of
control messages of the upper layers (e.g., IPv6) and the continuity 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 of sessions in the higher layers (e.g., IPv6, TCP, and UDP). Hence,
the bandwidth selection according to Modulation and Coding Scheme the bandwidth selection according to Modulation and Coding Scheme
(MCS) also affects the vehicular network connectivity. Note that (MCS) also affects the vehicular network connectivity. Note that
usually the higher bandwidth gives the shorter communication range usually the higher bandwidth gives the shorter communication range
and the higher packet error rate at the receiving side, which may and the higher packet error rate at the receiving side, which may
reduce the reliability of control message exchanges of the higher reduce the reliability of control message exchanges of the higher
layers (e.g., IPv6). This section presents key topics such as layers (e.g., IPv6). This section presents key topics such as
neighbor discovery and mobility management for links and sessions in neighbor discovery and mobility management for links and sessions in
IPv6-based vehicular networks. IPv6-based vehicular networks. Note that the detailed discussion on
the transport-layer session mobility and usage of available bandwidth
to fulfill the use cases is left as potential future work.
5.1. Neighbor Discovery 5.1. Neighbor Discovery
IPv6 ND [RFC4861][RFC4862] is a core part of the IPv6 protocol suite. IPv6 ND [RFC4861][RFC4862] is a core part of the IPv6 protocol suite.
IPv6 ND is designed for link types including point-to-point, IPv6 ND is designed for link types including point-to-point,
multicast-capable (e.g., Ethernet) and Non-Broadcast Multiple Access multicast-capable (e.g., Ethernet) and Non-Broadcast Multiple Access
(NBMA). It assumes the efficient and reliable support of multicast (NBMA). It assumes the efficient and reliable support of multicast
and unicast from the link layer for various network operations such and unicast from the link layer for various network operations such
as MAC Address Resolution (AR), DAD, MLD and Neighbor Unreachability as MAC Address Resolution (AR), DAD, MLD and Neighbor Unreachability
Detection (NUD). Detection (NUD).
skipping to change at page 23, line 45 skipping to change at page 24, line 5
address. An efficient NUD is required to reduce the overhead of the 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 NUD packets during a vehicle's travel in a road network, which can
guarantee the accurate neighborhood information of a vehicle in terms guarantee the accurate neighborhood information of a vehicle in terms
of adjacent vehicles and RSUs. of adjacent vehicles and RSUs.
The legacy DAD assumes that a node with an IPv6 address can reach any 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 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 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 party within the scope of its address for the duration of the address
ownership. However, the partitioning and merging of VANETs makes ownership. However, the partitioning and merging of VANETs makes
this assumption frequently invalid in vehicular networks. The this assumption be not valid frequently in vehicular networks. The
merging and partitioning of VANETs frequently occurs in vehicular merging and partitioning of VANETs frequently occurs in vehicular
networks. This merging and partitioning should be considered for the networks. This merging and partitioning should be considered for the
IPv6 ND such as IPv6 Stateless Address Autoconfiguration (SLAAC) IPv6 ND such as IPv6 Stateless Address Autoconfiguration (SLAAC)
[RFC4862]. Due to the merging of VANETs, two IPv6 addresses may [RFC4862]. SLAAC is not compatible with merging and partitioning,
and additional work is needed for ND to operate properly under those
circumstances. Due to the merging of VANETs, two IPv6 addresses may
conflict with each other though they were unique before the merging. 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 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 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 will be configured by a vehicle as DAD. Also, the partitioning of a
VANET may make vehicles with the same prefix be physically VANET may make vehicles with the same prefix be physically
unreachable. An address lookup operation may be conducted by an MA 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 or IP-RSU (as Registrar in RPL) to check the existence of a vehicle
under the network coverage of the MA or IP-RSU as NUD. Thus, SLAAC 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 needs to prevent IPv6 address duplication due to the merging of
VANETs, and IPv6 ND needs to detect unreachable neighboring vehicles VANETs, and IPv6 ND needs to detect unreachable neighboring vehicles
skipping to change at page 25, line 4 skipping to change at page 25, line 28
emergency situation, such as a rear-end crash. emergency situation, such as a rear-end crash.
ND time-related parameters such as router lifetime and Neighbor ND time-related parameters such as router lifetime and Neighbor
Advertisement (NA) interval need to be adjusted for vehicle speed and Advertisement (NA) interval need to be adjusted for vehicle speed and
vehicle density. For example, the NA interval needs to be vehicle density. For example, the NA interval needs to be
dynamically adjusted according to a vehicle's speed so that the dynamically adjusted according to a vehicle's speed so that the
vehicle can maintain its neighboring vehicles in a stable way, vehicle can maintain its neighboring vehicles in a stable way,
considering the collision probability with the NA messages sent by considering the collision probability with the NA messages sent by
other vehicles. The ND time-related parameters can be an operational other vehicles. The ND time-related parameters can be an operational
setting or an optimization point particularly for vehicular networks. setting or an optimization point particularly for vehicular networks.
Note that the link-scope multicast messages in ND protocol may cause
the performance issue in vehicular networks. [RFC9119] suggests
several optimization approaches for the issue.
For IPv6-based safety applications (e.g., context-aware navigation, For IPv6-based safety applications (e.g., context-aware navigation,
adaptive cruise control, and platooning) in vehicular networks, the adaptive cruise control, and platooning) in vehicular networks, the
delay-bounded data delivery is critical. IPv6 ND needs to work to delay-bounded data delivery is critical. IPv6 ND needs to work to
support those IPv6-based safety applications efficiently. support those IPv6-based safety applications efficiently.
[I-D.jeong-ipwave-vehicular-neighbor-discovery] introduces a
Vehicular Neighbor Discovery (VND) process as an extension of IPv6 ND
for IP-based vehicular networks.
From the interoperability point of view, in IPv6-based vehicular From the interoperability point of view, in IPv6-based vehicular
networking, IPv6 ND should have minimum changes with the legacy IPv6 networking, IPv6 ND should have minimum changes with the legacy IPv6
ND used in the Internet, including DAD and NUD operations, so that ND used in the Internet, including DAD and NUD operations, so that
IPv6-based vehicular networks can be seamlessly connected to other IPv6-based vehicular networks can be seamlessly connected to other
intelligent transportation elements (e.g., traffic signals, intelligent transportation elements (e.g., traffic signals,
pedestrian wearable devices, electric scooters, and bus stops) that pedestrian wearable devices, electric scooters, and bus stops) that
use the standard IPv6 network settings. use the standard IPv6 network settings.
5.1.1. Link Model 5.1.1. Link Model
skipping to change at page 25, line 32 skipping to change at page 26, line 19
the vehicular network topology as long as there exist bidirectional the vehicular network topology as long as there exist bidirectional
E2E paths between them in the vehicular network including VANETs and E2E paths between them in the vehicular network including VANETs and
IP-RSUs. This subnet model allows vehicles with the same prefix to IP-RSUs. This subnet model allows vehicles with the same prefix to
communicate with each other via a combination of multihop V2V and communicate with each other via a combination of multihop V2V and
multihop V2I with VANETs and IP-RSUs. multihop V2I with VANETs and IP-RSUs.
[I-D.thubert-6man-ipv6-over-wireless] introduces other issues in an [I-D.thubert-6man-ipv6-over-wireless] introduces other issues in an
IPv6 subnet model. IPv6 subnet model.
IPv6 protocols work under certain assumptions that do not necessarily IPv6 protocols work under certain assumptions that do not necessarily
hold for vehicular wireless access link types [VIP-WAVE][RFC5889]. hold for vehicular wireless access link types [VIP-WAVE][RFC5889].
For instance, some IPv6 protocols assume symmetry in the connectivity For instance, some IPv6 protocols such as NUD [RFC4861] and MIPv6
among neighboring interfaces [RFC6250]. However, radio interference [RFC6275] assume symmetry in the connectivity among neighboring
and different levels of transmission power may cause asymmetric links interfaces. However, radio interference and different levels of
to appear in vehicular wireless links. As a result, a new vehicular transmission power may cause asymmetric links to appear in vehicular
link model needs to consider the asymmetry of dynamically changing wireless links [RFC6250]. As a result, a new vehicular link model
vehicular wireless links. needs to consider the asymmetry of dynamically changing vehicular
wireless links.
There is a relationship between a link and a prefix, besides the There is a relationship between a link and a prefix, besides the
different scopes that are expected from the link-local, unique-local, different scopes that are expected from the link-local, unique-local,
and global types of IPv6 addresses. In an IPv6 link, it is defined and global types of IPv6 addresses. In an IPv6 link, it is defined
that all interfaces which are configured with the same subnet prefix 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 and with on-link bit set can communicate with each other on an IPv6
link. However, the vehicular link model needs to define the link. However, the vehicular link model needs to define the
relationship between a link and a prefix, considering the dynamics of relationship between a link and a prefix, considering the dynamics of
wireless links and the characteristics of VANET. wireless links and the characteristics of VANET.
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indirectly via IP-RSUs. On the other hand, when Vehicle1 and indirectly via IP-RSUs. On the other hand, when Vehicle1 and
Vehicle3 are far away from direct communication range in separate Vehicle3 are far away from direct communication range in separate
VANETs and under two different IP-RSUs, they can communicate with VANETs and under two different IP-RSUs, they can communicate with
each other through the relay of IP-RSUs via V2I2V. Thus, two each other through the relay of IP-RSUs via V2I2V. Thus, two
separate VANETs can merge into one network via IP-RSU(s). Also, separate VANETs can merge into one network via IP-RSU(s). Also,
newly arriving vehicles can merge two separate VANETs into one VANET newly arriving vehicles can merge two separate VANETs into one VANET
if they can play the role of a relay node for those VANETs. if they can play the role of a relay node for those VANETs.
Thus, in IPv6-based vehicular networking, the vehicular link model Thus, in IPv6-based vehicular networking, the vehicular link model
should have minimum changes for interoperability with standard IPv6 should have minimum changes for interoperability with standard IPv6
links in an efficient fashion to support IPv6 DAD, MLD and NUD links efficiently to support IPv6 DAD, MLD and NUD operations.
operations.
5.1.2. MAC Address Pseudonym 5.1.2. MAC Address Pseudonym
For the protection of drivers' privacy, a pseudonym of a MAC address 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 of a vehicle's network interface should be used, so that the MAC
address can be changed periodically. However, although such a address can be changed periodically. However, although such a
pseudonym of a MAC address can protect to some extent the privacy of 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 a vehicle, it may not be able to resist attacks on vehicle
identification by other fingerprint information, for example, the identification by other fingerprint information, for example, the
scrambler seed embedded in IEEE 802.11-OCB frames [Scrambler-Attack]. 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 Note that [I-D.ietf-madinas-mac-address-randomization] discusses more
an IPv6 address pair. However, the pseudonym handling is not about MAC address randomization, and [I-D.ietf-madinas-use-cases]
implemented and tested yet for applications on IP-based vehicular describes several use cases for MAC address randomization.
networking.
In the ETSI standards, for the sake of security and privacy, an ITS In the ETSI standards, for the sake of security and privacy, an ITS
station (e.g., vehicle) can use pseudonyms for its network interface station (e.g., vehicle) can use pseudonyms for its network interface
identities (e.g., MAC address) and the corresponding IPv6 addresses identities (e.g., MAC address) and the corresponding IPv6 addresses
[Identity-Management]. Whenever the network interface identifier [Identity-Management]. Whenever the network interface identifier
changes, the IPv6 address based on 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 needs to be updated, and the uniqueness of the address needs to be
checked through DAD procedure. checked through DAD procedure.
5.1.3. Routing 5.1.3. Routing
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state that needs to be exchanged. As a result, the routing protocol state that needs to be exchanged. As a result, the routing protocol
overhead is minimized, which allows either highly constrained stable overhead is minimized, which allows either highly constrained stable
networks or less constrained, highly dynamic networks. Refer to networks or less constrained, highly dynamic networks. Refer to
Appendix B for the detailed description of RPL for multihop V2X Appendix B for the detailed description of RPL for multihop V2X
networking. networking.
An address registration extension for 6LoWPAN (IPv6 over Low-Power An address registration extension for 6LoWPAN (IPv6 over Low-Power
Wireless Personal Area Network) in [RFC8505] can support light-weight Wireless Personal Area Network) in [RFC8505] can support light-weight
mobility for nodes moving through different parents. [RFC8505], as mobility for nodes moving through different parents. [RFC8505], as
opposed to [RFC4861], is stateful and proactively installs the ND opposed to [RFC4861], is stateful and proactively installs the ND
cache entries, which saves broadcasts and provides a deterministic cache entries, which saves broadcasts and provides deterministic
presence information for IPv6 addresses. Mainly it updates the presence information for IPv6 addresses. Mainly it updates the
Address Registration Option (ARO) of ND defined in [RFC6775] to Address Registration Option (ARO) of ND defined in [RFC6775] to
include a status field that can indicate the movement of a node and 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 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, can be used to determine the most recent location of a node. Thus,
RPL can use the information provided by the Extended ARO (EARO) RPL can use the information provided by the Extended ARO (EARO)
defined in [RFC8505] to deal with a certain level of node mobility. 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 When a leaf node moves to the coverage of another parent node, it
should de-register its addresses to the previous parent node and should de-register its addresses to the previous parent node and
register itself with a new parent node along with an incremented TID. 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 RPL can be used in IPv6-based vehicular networks, but it is primarily
designed for lossy networks, which puts energy efficiency first. For designed for low-power networks, which puts energy efficiency first.
using it in IPv6-based vehicular networks, there have not been actual For using it in IPv6-based vehicular networks, there have not been
experiences and practical implementations for vehicular networks, actual experiences and practical implementations, though it was
though it was tested in IoT low-power and lossy networks (LLN) tested in IoT low-power and lossy networks (LLN) scenarios. Another
scenarios. concern is that RPL may generate excessive topology discovery
messages in a highly moving environment such as vehicular networks.
This issue can be an operational or optimization point for a
practitioner.
Moreover, due to bandwidth and energy constraints, RPL does not Moreover, due to bandwidth and energy constraints, RPL does not
suggest to use a proactive mechanism (e.g., keepalive) to maintain suggest using a proactive mechanism (e.g., keepalive) to maintain
accurate routing adjacencies such as Bidirectional Forwarding accurate routing adjacencies such as Bidirectional Forwarding
Detection [RFC5881] and MANET Neighborhood Discovery Protocol Detection [RFC5881] and MANET Neighborhood Discovery Protocol
[RFC6130]. As a result, due to the mobility of vehicles, network [RFC6130]. As a result, due to the mobility of vehicles, network
fragmentation may not be detected quickly and the routing of packets fragmentation may not be detected quickly and the routing of packets
between vehicles or between a vehicle and an infrastructure node may between vehicles or between a vehicle and an infrastructure node may
fail. fail.
5.2. Mobility Management 5.2. Mobility Management
The seamless connectivity and timely data exchange between two end The seamless connectivity and timely data exchange between two end
points requires efficient mobility management including location points requires efficient mobility management including location
management and handover. Most vehicles are equipped with a GPS management and handover. Most vehicles are equipped with a GNSS
receiver as part of a dedicated navigation system or a corresponding receiver as part of a dedicated navigation system or a corresponding
smartphone App. Note that the GPS receiver may not provide vehicles smartphone App. Note that the GNSS receiver may not provide vehicles
with accurate location information in adverse environments such as a with accurate location information in adverse environments such as a
building area or a tunnel. The location precision can be improved building area or a tunnel. The location precision can be improved
with assistance of the IP-RSUs or a cellular system with a GPS with assistance of the IP-RSUs or a cellular system with a GNSS
receiver for location information. receiver for location information.
With a GPS navigator, efficient mobility management can be performed With a GNSS navigator, efficient mobility management can be performed
with the help of vehicles periodically reporting their current with the help of vehicles periodically reporting their current
position and trajectory (i.e., navigation path) to the vehicular position and trajectory (i.e., navigation path) to the vehicular
infrastructure (having IP-RSUs and an MA in TCC). This vehicular infrastructure (having IP-RSUs and an MA in TCC). This vehicular
infrastructure can predict the future positions of the vehicles from infrastructure can predict the future positions of the vehicles from
their mobility information (i.e., the current position, speed, their mobility information (i.e., the current position, speed,
direction, and trajectory) for efficient mobility management (e.g., direction, and trajectory) for efficient mobility management (e.g.,
proactive handover). For a better proactive handover, link-layer proactive handover). For a better proactive handover, link-layer
parameters, such as the signal strength of a link-layer frame (e.g., parameters, such as the signal strength of a link-layer frame (e.g.,
Received Channel Power Indicator (RCPI) [VIP-WAVE]), can be used to Received Channel Power Indicator (RCPI) [VIP-WAVE]), can be used to
determine the moment of a handover between IP-RSUs along with determine the moment of a handover between IP-RSUs along with
skipping to change at page 30, line 7 skipping to change at page 30, line 28
For example, as shown in Figure 1, when a vehicle (e.g., Vehicle2) is 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 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 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 subnet, the IP-RSUs can proactively support the IPv6 mobility of the
vehicle, while performing the SLAAC, data forwarding, and handover vehicle, while performing the SLAAC, data forwarding, and handover
for the sake of the vehicle. for the sake of the vehicle.
For a mobility management scheme in a domain, where the wireless For a mobility management scheme in a domain, where the wireless
subnets of multiple IP-RSUs share the same prefix, an efficient subnets of multiple IP-RSUs share the same prefix, an efficient
vehicular-network-wide DAD is required. If DHCPv6 is used to assign vehicular-network-wide DAD is required. On the other hand, for a
a unique IPv6 address to each vehicle in this shared link, DAD is not mobility management scheme with a unique prefix per mobile node
required. On the other hand, for a mobility management scheme with a (e.g., PMIPv6 [RFC5213]), DAD is not required because the IPv6
unique prefix per mobile node (e.g., PMIPv6 [RFC5213]), DAD is not address of a vehicle's external wireless interface is guaranteed to
required because the IPv6 address of a vehicle's external wireless be unique. There is a tradeoff between the prefix usage efficiency
interface is guaranteed to be unique. There is a tradeoff between and DAD overhead. Thus, the IPv6 address autoconfiguration for
the prefix usage efficiency and DAD overhead. Thus, the IPv6 address vehicular networks needs to consider this tradeoff to support
autoconfiguration for vehicular networks needs to consider this efficient mobility management.
tradeoff to support efficient mobility management.
Even though the SLAAC with classic ND costs a DAD during mobility Even though the SLAAC with classic ND costs a DAD during mobility
management, the SLAAC with [RFC8505] and/or AERO/OMNI do not cost a management, the SLAAC with [RFC8505] and/or AERO/OMNI do not cost a
DAD. SLAAC for vehicular networks needs to consider the minimization 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- 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 RSU and MA). Using an infrastructure prefix over VANET allows direct
routability to the Internet through the multihop V2I toward an IP- routability to the Internet through the multihop V2I toward an IP-
RSU. On the other hand, a BYOA does not allow such direct RSU. On the other hand, a BYOA does not allow such direct
routability to the Internet since the BYOA is not topologically routability to the Internet since the BYOA is not topologically
correct, that is, not routable in the Internet. In addition, a correct, that is, not routable in the Internet. In addition, a
vehicle configured with a BYOA needs a tunnel home (e.g., IP-RSU) vehicle configured with a BYOA needs a tunnel home (e.g., IP-RSU)
connected to the Internet, and the vehicle needs to know which connected to the Internet, and the vehicle needs to know which
neighboring vehicle is reachable inside the VANET toward the tunnel neighboring vehicle is reachable inside the VANET toward the tunnel
home. There is nonnegligible control overhead to set up and maintain home. There is non-negligible control overhead to set up and
routes to such a tunnel home [RFC4888] over the VANET. maintain routes to such a tunnel home [RFC4888] over the VANET.
For the case of a multihomed network, a vehicle can follow the first- For the case of a multihomed network, a vehicle can follow the first-
hop router selection rule described in [RFC8028]. For example, an hop router selection rule described in [RFC8028]. For example, an
IP-OBU inside a vehicle may connect to an IP-RSU that has multiple 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 routers behind. In this scenario, because the IP-OBU can have
multiple prefixes from those routers, the default router selection, multiple prefixes from those routers, the default router selection,
source address selection, and packet redirect process should follow source address selection, and packet redirect process should follow
the guidelines in [RFC8028]. That is, the vehicle should select its the guidelines in [RFC8028]. That is, the vehicle should select its
default router for each prefix by preferring the router that default router for each prefix by preferring the router that
advertised the prefix. advertised the prefix.
Vehicles can use the TCC as their Home Network having a home agent Vehicles can use the TCC as their Home Network having a home agent
for mobility management as in MIPv6 [RFC6275], PMIPv6 [RFC5213], and for mobility management as in MIPv6 [RFC6275], PMIPv6 [RFC5213], and
NEMO [RFC3963], so the TCC (or an MA inside the TCC) maintains the NEMO [RFC3963], so the TCC (or an MA inside the TCC) maintains the
mobility information of vehicles for location management. Also, in mobility information of vehicles for location management. Also, in
vehicular networks, asymmetric links sometimes exist and must be vehicular networks, asymmetric links sometimes exist and must be
considered for wireless communications such as V2V and V2I. considered for wireless communications such as V2V and V2I.
[I-D.jeong-ipwave-vehicular-mobility-management] discusses a
Vehicular Mobility Management (VMM) scheme to proactively do handover
for vehicles.
Therefore, for the proactive and seamless IPv6 mobility of vehicles, Therefore, for the proactive and seamless IPv6 mobility of vehicles,
the vehicular infrastructure (including IP-RSUs and MA) needs to the vehicular infrastructure (including IP-RSUs and MA) needs to
efficiently perform the mobility management of the vehicles with efficiently perform the mobility management of the vehicles with
their mobility information and link-layer information. Also, in their mobility information and link-layer information. Also, in
IPv6-based vehicular networking, IPv6 mobility management should have IPv6-based vehicular networking, IPv6 mobility management should have
minimum changes for the interoperability with the legacy IPv6 minimum changes for the interoperability with the legacy IPv6
mobility management schemes such as PMIPv6, DMM, LISP, and AERO. mobility management schemes such as PMIPv6, DMM, LISP, and AERO.
6. Security Considerations 6. Security Considerations
This section discusses security and privacy for IPv6-based vehicular This section discusses security and privacy for IPv6-based vehicular
networking. Security and privacy are paramount in V2I, V2V, and V2X networking. Security and privacy are paramount in V2I, V2V, and V2X
networking along with neighbor discovery and mobility management. networking along with neighbor discovery and mobility management.
Vehicles and infrastructure must be authenticated in order to Vehicles and infrastructure must be authenticated to each other by a
participate in vehicular networking. For the authentication in password, a key, and/or a fingerprint in order to participate in
vehicular networks, vehicular cloud needs to support a kind of Public vehicular networking. For the authentication in vehicular networks,
Key Infrastructure (PKI) in an efficient way. To provide safe vehicular cloud needs to support a Public Key Infrastructure (PKI)
interaction between vehicles or between a vehicle and infrastructure, efficiently, as either a dedicated or a co-located component inside a
only authenticated nodes (i.e., vehicle and infrastructure node) can TCC. To provide safe interaction between vehicles or between a
participate in vehicular networks. Also, in-vehicle devices (e.g., vehicle and infrastructure, only authenticated nodes (i.e., vehicle
ECU) and a driver/passenger's mobile devices (e.g., smartphone and and infrastructure node) can participate in vehicular networks.
tablet PC) in a vehicle need to communicate with other in-vehicle Also, in-vehicle devices (e.g., ECU) and a driver/passenger's mobile
devices and another driver/passenger's mobile devices in another devices (e.g., smartphone and tablet PC) in a vehicle need to
vehicle, or other servers behind an IP-RSU in a secure way. Even communicate with other in-vehicle devices and another driver/
though a vehicle is perfectly authenticated and legitimate, it may be passenger's mobile devices in another vehicle, or other servers
hacked for running malicious applications to track and collect its behind an IP-RSU securely. Even though a vehicle is perfectly
and other vehicles' information. In this case, an attack mitigation authenticated by another entity and legitimate to use the data
process may be required to reduce the aftermath of malicious generated by another vehicle, it may be hacked for running malicious
behaviors. Note that when driver/passenger's mobile devices are applications to track and collect its and other vehicles'
connected to a vehicle's internal network, the vehicle may be more information. In this case, an attack mitigation process may be
vulnerable to possible attacks from external networks. required to reduce the aftermath of malicious behaviors. Note that
when driver/passenger's mobile devices are connected to a vehicle's
internal network, the vehicle may be more vulnerable to possible
attacks from external networks due to the exposure of its in-flight
traffic packets. [I-D.jeong-ipwave-security-privacy] discusses
several types of threats for Vehicular Security and Privacy (VSP).
For secure V2I communication, a secure channel (e.g., IPsec) between 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., 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 IP-RSU) in an EN needs to be established, as shown in Figure 2
[RFC4301][RFC4302] [RFC4303][RFC4308] [RFC7296]. Also, for secure [RFC4301][RFC4302] [RFC4303][RFC4308] [RFC7296]. Also, for secure
V2V communication, a secure channel (e.g., IPsec) between a mobile 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) 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. 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 For secure V2I/V2V 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 establish a secure connection (e.g., TLS) with another element in
another vehicle or another element in a vehicular cloud (e.g., a another vehicle or another element in a vehicular cloud (e.g., a
server). IEEE 1609.2 [WAVE-1609.2] specifies security services for server). Note that any key management approach can be used for the
secure communication, and particularly for IPv6-based vehicular
networks, a new or enhanced key management approach resilient to
wireless networks is required.
IEEE 1609.2 [WAVE-1609.2] specifies security services for
applications and management messages, but this WAVE specification is applications and management messages, but this WAVE specification is
optional. Thus, if the link layer does not support the security of a 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 WAVE frame, either the network layer or the transport layer needs to
support security services for the WAVE frames. support security services for the WAVE frames.
6.1. Security Threats in Neighbor Discovery 6.1. Security Threats in Neighbor Discovery
For the classical IPv6 ND, DAD is required to ensure the uniqueness For the classical IPv6 ND (i.e., the legacy ND), DAD is required to
of the IPv6 address of a vehicle's wireless interface. This DAD can ensure the uniqueness of the IPv6 address of a vehicle's wireless
be used as a flooding attack that uses the DAD-related ND packets interface. This DAD can be used as a flooding attack that uses the
disseminated over the VANET or vehicular networks. [RFC6959] DAD-related ND packets disseminated over the VANET or vehicular
introduces threats enabled by IP source address spoofing. This networks. [RFC6959] introduces threats enabled by IP source address
possibility indicates that vehicles and IP-RSUs need to filter out spoofing. This possibility indicates that vehicles and IP-RSUs need
suspicious ND traffic in advance. [RFC8928] introduces a mechanism to filter out suspicious ND traffic in advance. [RFC8928] introduces
that protects the ownership of an address for 6loWPAN ND from address a mechanism that protects the ownership of an address for 6loWPAN ND
theft and impersonation attacks. Based on the SEND [RFC3971] from address theft and impersonation attacks. Based on the SEND
mechanism, the authentication for routers (i.e., IP-RSUs) can be [RFC3971] mechanism, the authentication for routers (i.e., IP-RSUs)
conducted by only selecting an IP-RSU that has a certification path can be conducted by only selecting an IP-RSU that has a certification
toward trusted parties. For authenticating other vehicles, the path toward trusted parties. For authenticating other vehicles,
cryptographically generated address (CGA) can be used to verify the cryptographically generated addresses (CGA) can be used to verify the
true owner of a received ND message, which requires to use the CGA ND true owner of a received ND message, which requires using the CGA ND
option in the ND protocols. For a general protection of the ND option in the ND protocol. This CGA can protect vehicles against DAD
mechanism, the RSA Signature ND option can also be used to protect flooding by DAD filtering based on the verification for the true
owner of the received DAD message. 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 the integrity of the messages by public key signatures. For a more
advanced authentication mechanism, a distributed blockchain-based advanced authentication mechanism, a distributed blockchain-based
approach [Vehicular-BlockChain] can be used. However, for a scenario approach [Vehicular-BlockChain] can be used. However, for a scenario
where a trustable router or an authentication path cannot be where a trustable router or an authentication path cannot be
obtained, it is desirable to find a solution in which vehicles and obtained, it is desirable to find a solution in which vehicles and
infrastructures can authenticate each other without any support from infrastructures can authenticate each other without any support from
a third party. a third party.
When applying the classical IPv6 ND process to VANET, one of the 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 security issues is that an IP-RSU (or an IP-OBU) as a router may
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Strong security measures shall protect vehicles roaming in road Strong security measures shall protect vehicles roaming in road
networks from the attacks of malicious nodes, which are controlled by networks from the attacks of malicious nodes, which are controlled by
hackers. For safe driving applications (e.g., context-aware hackers. For safe driving applications (e.g., context-aware
navigation, cooperative adaptive cruise control, and platooning), as navigation, cooperative adaptive cruise control, and platooning), as
explained in Section 3.1, the cooperative action among vehicles is explained in Section 3.1, the cooperative action among vehicles is
assumed. Malicious nodes may disseminate wrong driving information assumed. Malicious nodes may disseminate wrong driving information
(e.g., location, speed, and direction) for disturbing safe driving. (e.g., location, speed, and direction) for disturbing safe driving.
For example, a Sybil attack, which tries to confuse a vehicle with For example, a Sybil attack, which tries to confuse a vehicle with
multiple false identities, may disturb a vehicle from taking a safe multiple false identities, may disturb a vehicle from taking a safe
maneuver. Since cyber security issues in vehicular networks may maneuver. Since cybersecurity issues in vehicular networks may cause
cause physical vehicle safety issues, it may be necessary to consider physical vehicle safety issues, it may be necessary to consider those
those physical security concerns when designing protocols in IPWAVE. physical security concerns when designing protocols in IPWAVE.
To identify malicious vehicles among vehicles, an authentication To identify malicious vehicles among vehicles, an authentication
method may be required. A Vehicle Identification Number (VIN) and a method may be required. A Vehicle Identification Number (VIN) (or a
user certificate (e.g., X.509 certificate [RFC5280]) along with an vehicle manufacturer certificate) and a user certificate (e.g., X.509
in-vehicle device's identifier generation can be used to efficiently certificate [RFC5280]) along with an in-vehicle device's identifier
authenticate a vehicle or its driver (having a user certificate) generation can be used to efficiently authenticate a vehicle or its
through a road infrastructure node (e.g., IP-RSU) connected to an driver (having a user certificate) through a road infrastructure node
authentication server in the vehicular cloud. This authentication (e.g., IP-RSU) connected to an authentication server in the vehicular
can be used to identify the vehicle that will communicate with an cloud. This authentication can be used to identify the vehicle that
infrastructure node or another vehicle. In the case where a vehicle will communicate with an infrastructure node or another vehicle. In
has an internal network (called Moving Network) and elements in the the case where a vehicle has an internal network (called Moving
network (e.g., in-vehicle devices and a user's mobile devices), as Network) and elements in the network (e.g., in-vehicle devices and a
shown in Figure 2, the elements in the network need to be user's mobile devices), as shown in Figure 2, the elements in the
authenticated individually for safe authentication. Also, Transport network need to be authenticated individually for safe
Layer Security (TLS) certificates [RFC8446][RFC5280] can be used for authentication. Also, Transport Layer Security (TLS) certificates
an element's authentication to allow secure E2E vehicular [RFC8446][RFC5280] can be used for an element's authentication to
communications between an element in a vehicle and another element in allow secure E2E vehicular communications between an element in a
a server in a vehicular cloud, or between an element in a vehicle and vehicle and another element in a server in a vehicular cloud, or
another element in another vehicle. between an element in a vehicle and another element in another
vehicle.
6.2. Security Threats in Mobility Management 6.2. Security Threats in Mobility Management
For mobility management, a malicious vehicle can construct multiple For mobility management, a malicious vehicle can construct multiple
virtual bogus vehicles, and register them with IP-RSUs and MA. This virtual bogus vehicles, and register them with IP-RSUs and MA. This
registration makes the IP-RSUs and MA waste their resources. The IP- 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 RSUs and MA need to determine whether a vehicle is genuine or bogus
in mobility management. Also, the confidentiality of control packets in mobility management. Also, the confidentiality of control packets
and data packets among IP-RSUs and MA, the E2E paths (e.g., tunnels) and data packets among IP-RSUs and MA, the E2E paths (e.g., tunnels)
need to be protected by secure communication channels. In addition, need to be protected by secure communication channels. In addition,
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increase the construction time of a connection or some vehicles may increase the construction time of a connection or some vehicles may
not be able to be authenticated. not be able to be authenticated.
Even though vehicles can be authenticated with valid certificates by Even though vehicles can be authenticated with valid certificates by
an authentication server in the vehicular cloud, the authenticated an authentication server in the vehicular cloud, the authenticated
vehicles may harm other vehicles. To deal with this kind of security vehicles may harm other vehicles. To deal with this kind of security
issue, for monitoring suspicious behaviors, vehicles' communication issue, for monitoring suspicious behaviors, vehicles' communication
activities can be recorded in either a central way through a logging 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., server (e.g., TCC) in the vehicular cloud or a distributed way (e.g.,
blockchain [Bitcoin]) along with other vehicles or infrastructure. blockchain [Bitcoin]) along with other vehicles or infrastructure.
The trade-offs between central and distributed ways can be that using
a centralized approach may cause a higher delay when accessing the
log information as a distributed approach is closer to a scene. A
distributed approach may also provide more local information for an
operator to analyze the activities of vehicles instead of retrieving
log information from a centralized logging system. The logged
information can be accessed by a suspicious vehicle's neighboring
vehicles and any authorized remote entity (e.g., a vehicle
manufacturer and a security service provider for vehicular networks).
The information of communication activities for vehicles is sensitive
since it discloses the network behavior and status of a vehicle such
as the count of TCP sessions established.
To solve the issue ultimately, we need a solution where, without To solve the issue ultimately, we need a solution where, without
privacy breakage, vehicles may observe activities of each other to privacy breakage, vehicles may observe activities of each other to
identify any misbehavior. Once identifying a misbehavior, a vehicle identify any misbehavior. Once identifying a misbehavior, a vehicle
shall have a way to either isolate itself from others or isolate a shall have a way to either isolate itself from others or isolate a
suspicious vehicle by informing other vehicles. Alternatively, for suspicious vehicle by informing other vehicles. Alternatively, for
completely secure vehicular networks, we shall embrace the concept of completely secure vehicular networks, we shall embrace the concept of
"zero-trust" for vehicles in which no vehicle is trustable and "zero-trust" for vehicles in which no vehicle is trustable and
verifying every message is necessary. For doing so, we shall have an verifying every message (such as IPv6 control messages including ND,
efficient zero-trust framework or mechanism for vehicular networks. DAD, NUD, and application layer messages) is necessary. In this way,
a failure to prevent a cyberattack shall never happen on a vehicular
network. Thus, we need to have an efficient zero-trust framework or
mechanism for vehicular networks.
For the non-repudiation of the harmful activities of malicious nodes, For the non-repudiation of the harmful activities from malicious
a blockchain technology can be used [Bitcoin]. Each message from a vehicles, which it is difficult for other normal vehicles to identify
vehicle can be treated as a transaction and the neighboring vehicles them, an additional and advanced approach is needed. One possible
can play the role of peers in a consensus method of a blockchain approach is to use a blockchain-based approach [Bitcoin] as an IPv6
[Bitcoin] [Vehicular-BlockChain]. For a blockchain's efficient security checking framework. Each IPv6 packet from a vehicle can be
consensus in vehicular networks having fast moving vehicles, a new treated as a transaction and the neighboring vehicles can play the
consensus algorithm needs to be developed or an existing consensus role of peers in a consensus method of a blockchain [Bitcoin]
algorithm needs to be enhanced. [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. In addition, a consensus-based mechanism for
the security of vehicular networks in the IPv6 layer can also be
considered. A group of servers as blockchain infrastructure can be
part of the security checking process in the IP layer.
To prevent an adversary from tracking a vehicle with its MAC address To prevent an adversary from tracking a vehicle with its MAC address
or IPv6 address, especially for a long-living transport-layer session or IPv6 address, especially for a long-living transport-layer session
(e.g., voice call over IP and video streaming service), a MAC address (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 pseudonym needs to be provided to each vehicle; that is, each vehicle
periodically updates its MAC address and its IPv6 address needs to be periodically updates its MAC address and its IPv6 address needs to be
updated accordingly by the MAC address change [RFC4086][RFC8981]. updated accordingly by the MAC address change [RFC4086][RFC8981].
Such an update of the MAC and IPv6 addresses should not interrupt the Such an update of the MAC and IPv6 addresses should not interrupt the
E2E communications between two vehicles (or between a vehicle and an E2E communications between two vehicles (or between a vehicle and an
IP-RSU) for a long-living transport-layer session. However, if this IP-RSU) for a long-living transport-layer session. However, if this
pseudonym is performed without strong E2E confidentiality (using pseudonym is performed without strong E2E confidentiality (using
either IPsec or TLS), there will be no privacy benefit from changing either IPsec or TLS), there will be no privacy benefit from changing
MAC and IPv6 addresses, because an adversary can observe the change MAC and IPv6 addresses, because an adversary can observe the change
of the MAC and IPv6 addresses and track the vehicle with those of the MAC and IPv6 addresses and track the vehicle with those
addresses. Thus, the MAC address pseudonym and the IPv6 address addresses. Thus, the MAC address pseudonym and the IPv6 address
update should be performed with strong E2E confidentiality. Privacy update should be performed with strong E2E confidentiality.
concerns for excessively collecting vehicle activities from roadway
operators such as public transportation administrators and private The privacy exposure to the TCC and via V2I is mostly about the
contractors may also pose threats on violating privacy rights of location information of vehicles, and may also include other in-
vehicles. It might be interesting to find a solution from a vehicle activities such as transactions of credit cards. The assumed
technology point of view along with public policy development for the trusted actors are the owner of a vehicle, an authorized vehicle
issue. service provider (e.g., navigation service provider), and an
authorized vehicle manufacturer for providing after-sales services.
In addition, privacy concerns for excessively collecting vehicle
activities from roadway operators such as public transportation
administrators and private contractors may also pose threats on
violating privacy rights of vehicles. It might be interesting to
find a solution from a technology point of view along with public
policy development for the issue.
7. IANA Considerations 7. IANA Considerations
This document does not require any IANA actions. This document does not require any IANA actions.
8. References 8. References
8.1. Normative References 8.1. Normative References
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007,
<https://www.rfc-editor.org/info/rfc4861>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/info/rfc4862>.
[RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
2011, <https://www.rfc-editor.org/info/rfc6275>.
[RFC8691] Benamar, N., Härri, 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,
DOI 10.17487/RFC8691, December 2019,
<https://www.rfc-editor.org/info/rfc8691>.
8.2. Informative References
[RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast [RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast
Listener Discovery (MLD) for IPv6", RFC 2710, Listener Discovery (MLD) for IPv6", RFC 2710,
DOI 10.17487/RFC2710, October 1999, DOI 10.17487/RFC2710, October 1999,
<https://www.rfc-editor.org/info/rfc2710>. <https://www.rfc-editor.org/info/rfc2710>.
[RFC3626] Clausen, T., Ed. and P. Jacquet, Ed., "Optimized Link [RFC3626] Clausen, T., Ed. and P. Jacquet, Ed., "Optimized Link
State Routing Protocol (OLSR)", RFC 3626, State Routing Protocol (OLSR)", RFC 3626,
DOI 10.17487/RFC3626, October 2003, DOI 10.17487/RFC3626, October 2003,
<https://www.rfc-editor.org/info/rfc3626>. <https://www.rfc-editor.org/info/rfc3626>.
[RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related
Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004,
<https://www.rfc-editor.org/info/rfc3753>. <https://www.rfc-editor.org/info/rfc3753>.
[RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener [RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener
Discovery Version 2 (MLDv2) for IPv6", RFC 3810, Discovery Version 2 (MLDv2) for IPv6", RFC 3810,
DOI 10.17487/RFC3810, June 2004, DOI 10.17487/RFC3810, June 2004,
<https://www.rfc-editor.org/info/rfc3810>. <https://www.rfc-editor.org/info/rfc3810>.
[RFC3849] Huston, G., Lord, A., and P. Smith, "IPv6 Address Prefix
Reserved for Documentation", RFC 3849,
DOI 10.17487/RFC3849, July 2004,
<https://www.rfc-editor.org/info/rfc3849>.
[RFC3963] Devarapalli, V., Wakikawa, R., Petrescu, A., and P. [RFC3963] Devarapalli, V., Wakikawa, R., Petrescu, A., and P.
Thubert, "Network Mobility (NEMO) Basic Support Protocol", Thubert, "Network Mobility (NEMO) Basic Support Protocol",
RFC 3963, DOI 10.17487/RFC3963, January 2005, RFC 3963, DOI 10.17487/RFC3963, January 2005,
<https://www.rfc-editor.org/info/rfc3963>. <https://www.rfc-editor.org/info/rfc3963>.
[RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander,
"SEcure Neighbor Discovery (SEND)", RFC 3971, "SEcure Neighbor Discovery (SEND)", RFC 3971,
DOI 10.17487/RFC3971, March 2005, DOI 10.17487/RFC3971, March 2005,
<https://www.rfc-editor.org/info/rfc3971>. <https://www.rfc-editor.org/info/rfc3971>.
skipping to change at page 36, line 45 skipping to change at page 38, line 13
<https://www.rfc-editor.org/info/rfc4302>. <https://www.rfc-editor.org/info/rfc4302>.
[RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)",
RFC 4303, DOI 10.17487/RFC4303, December 2005, RFC 4303, DOI 10.17487/RFC4303, December 2005,
<https://www.rfc-editor.org/info/rfc4303>. <https://www.rfc-editor.org/info/rfc4303>.
[RFC4308] Hoffman, P., "Cryptographic Suites for IPsec", RFC 4308, [RFC4308] Hoffman, P., "Cryptographic Suites for IPsec", RFC 4308,
DOI 10.17487/RFC4308, December 2005, DOI 10.17487/RFC4308, December 2005,
<https://www.rfc-editor.org/info/rfc4308>. <https://www.rfc-editor.org/info/rfc4308>.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, [RFC4821] Mathis, M. and J. Heffner, "Packetization Layer Path MTU
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, Discovery", RFC 4821, DOI 10.17487/RFC4821, March 2007,
DOI 10.17487/RFC4861, September 2007, <https://www.rfc-editor.org/info/rfc4821>.
<https://www.rfc-editor.org/info/rfc4861>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/info/rfc4862>.
[RFC4885] Ernst, T. and H-Y. Lach, "Network Mobility Support [RFC4885] Ernst, T. and H-Y. Lach, "Network Mobility Support
Terminology", RFC 4885, DOI 10.17487/RFC4885, July 2007, Terminology", RFC 4885, DOI 10.17487/RFC4885, July 2007,
<https://www.rfc-editor.org/info/rfc4885>. <https://www.rfc-editor.org/info/rfc4885>.
[RFC4888] Ng, C., Thubert, P., Watari, M., and F. Zhao, "Network [RFC4888] Ng, C., Thubert, P., Watari, M., and F. Zhao, "Network
Mobility Route Optimization Problem Statement", RFC 4888, Mobility Route Optimization Problem Statement", RFC 4888,
DOI 10.17487/RFC4888, July 2007, DOI 10.17487/RFC4888, July 2007,
<https://www.rfc-editor.org/info/rfc4888>. <https://www.rfc-editor.org/info/rfc4888>.
skipping to change at page 38, line 14 skipping to change at page 39, line 18
[RFC6130] Clausen, T., Dearlove, C., and J. Dean, "Mobile Ad Hoc [RFC6130] Clausen, T., Dearlove, C., and J. Dean, "Mobile Ad Hoc
Network (MANET) Neighborhood Discovery Protocol (NHDP)", Network (MANET) Neighborhood Discovery Protocol (NHDP)",
RFC 6130, DOI 10.17487/RFC6130, April 2011, RFC 6130, DOI 10.17487/RFC6130, April 2011,
<https://www.rfc-editor.org/info/rfc6130>. <https://www.rfc-editor.org/info/rfc6130>.
[RFC6250] Thaler, D., "Evolution of the IP Model", RFC 6250, [RFC6250] Thaler, D., "Evolution of the IP Model", RFC 6250,
DOI 10.17487/RFC6250, May 2011, DOI 10.17487/RFC6250, May 2011,
<https://www.rfc-editor.org/info/rfc6250>. <https://www.rfc-editor.org/info/rfc6250>.
[RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
2011, <https://www.rfc-editor.org/info/rfc6275>.
[RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J., [RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J.,
Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur, Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur,
JP., and R. Alexander, "RPL: IPv6 Routing Protocol for JP., and R. Alexander, "RPL: IPv6 Routing Protocol for
Low-Power and Lossy Networks", RFC 6550, Low-Power and Lossy Networks", RFC 6550,
DOI 10.17487/RFC6550, March 2012, DOI 10.17487/RFC6550, March 2012,
<https://www.rfc-editor.org/info/rfc6550>. <https://www.rfc-editor.org/info/rfc6550>.
[RFC6583] Gashinsky, I., Jaeggli, J., and W. Kumari, "Operational [RFC6583] Gashinsky, I., Jaeggli, J., and W. Kumari, "Operational
Neighbor Discovery Problems", RFC 6583, Neighbor Discovery Problems", RFC 6583,
DOI 10.17487/RFC6583, March 2012, DOI 10.17487/RFC6583, March 2012,
<https://www.rfc-editor.org/info/rfc6583>. <https://www.rfc-editor.org/info/rfc6583>.
[RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
Bormann, "Neighbor Discovery Optimization for IPv6 over Bormann, "Neighbor Discovery Optimization for IPv6 over
Low-Power Wireless Personal Area Networks (6LoWPANs)", Low-Power Wireless Personal Area Networks (6LoWPANs)",
RFC 6775, DOI 10.17487/RFC6775, November 2012, RFC 6775, DOI 10.17487/RFC6775, November 2012,
<https://www.rfc-editor.org/info/rfc6775>. <https://www.rfc-editor.org/info/rfc6775>.
[RFC6959] McPherson, D., Baker, F., and J. Halpern, "Source Address
Validation Improvement (SAVI) Threat Scope", RFC 6959,
DOI 10.17487/RFC6959, May 2013,
<https://www.rfc-editor.org/info/rfc6959>.
[RFC7149] Boucadair, M. and C. Jacquenet, "Software-Defined [RFC7149] Boucadair, M. and C. Jacquenet, "Software-Defined
Networking: A Perspective from within a Service Provider Networking: A Perspective from within a Service Provider
Environment", RFC 7149, DOI 10.17487/RFC7149, March 2014, Environment", RFC 7149, DOI 10.17487/RFC7149, March 2014,
<https://www.rfc-editor.org/info/rfc7149>. <https://www.rfc-editor.org/info/rfc7149>.
[RFC7181] Clausen, T., Dearlove, C., Jacquet, P., and U. Herberg, [RFC7181] Clausen, T., Dearlove, C., Jacquet, P., and U. Herberg,
"The Optimized Link State Routing Protocol Version 2", "The Optimized Link State Routing Protocol Version 2",
RFC 7181, DOI 10.17487/RFC7181, April 2014, RFC 7181, DOI 10.17487/RFC7181, April 2014,
<https://www.rfc-editor.org/info/rfc7181>. <https://www.rfc-editor.org/info/rfc7181>.
skipping to change at page 39, line 16 skipping to change at page 40, line 21
Korhonen, "Requirements for Distributed Mobility Korhonen, "Requirements for Distributed Mobility
Management", RFC 7333, DOI 10.17487/RFC7333, August 2014, Management", RFC 7333, DOI 10.17487/RFC7333, August 2014,
<https://www.rfc-editor.org/info/rfc7333>. <https://www.rfc-editor.org/info/rfc7333>.
[RFC7429] Liu, D., Ed., Zuniga, JC., Ed., Seite, P., Chan, H., and [RFC7429] Liu, D., Ed., Zuniga, JC., Ed., Seite, P., Chan, H., and
CJ. Bernardos, "Distributed Mobility Management: Current CJ. Bernardos, "Distributed Mobility Management: Current
Practices and Gap Analysis", RFC 7429, Practices and Gap Analysis", RFC 7429,
DOI 10.17487/RFC7429, January 2015, DOI 10.17487/RFC7429, January 2015,
<https://www.rfc-editor.org/info/rfc7429>. <https://www.rfc-editor.org/info/rfc7429>.
[RFC7427] Kivinen, T. and J. Snyder, "Signature Authentication in
the Internet Key Exchange Version 2 (IKEv2)", RFC 7427,
DOI 10.17487/RFC7427, January 2015,
<https://www.rfc-editor.org/info/rfc7427>.
[RFC7466] Dearlove, C. and T. Clausen, "An Optimization for the [RFC7466] Dearlove, C. and T. Clausen, "An Optimization for the
Mobile Ad Hoc Network (MANET) Neighborhood Discovery Mobile Ad Hoc Network (MANET) Neighborhood Discovery
Protocol (NHDP)", RFC 7466, DOI 10.17487/RFC7466, March Protocol (NHDP)", RFC 7466, DOI 10.17487/RFC7466, March
2015, <https://www.rfc-editor.org/info/rfc7466>. 2015, <https://www.rfc-editor.org/info/rfc7466>.
[RFC8002] Heer, T. and S. Varjonen, "Host Identity Protocol
Certificates", RFC 8002, DOI 10.17487/RFC8002, October
2016, <https://www.rfc-editor.org/info/rfc8002>.
[RFC8028] Baker, F. and B. Carpenter, "First-Hop Router Selection by [RFC8028] Baker, F. and B. Carpenter, "First-Hop Router Selection by
Hosts in a Multi-Prefix Network", RFC 8028, Hosts in a Multi-Prefix Network", RFC 8028,
DOI 10.17487/RFC8028, November 2016, DOI 10.17487/RFC8028, November 2016,
<https://www.rfc-editor.org/info/rfc8028>. <https://www.rfc-editor.org/info/rfc8028>.
[RFC8175] Ratliff, S., Jury, S., Satterwhite, D., Taylor, R., and B. [RFC8175] Ratliff, S., Jury, S., Satterwhite, D., Taylor, R., and B.
Berry, "Dynamic Link Exchange Protocol (DLEP)", RFC 8175, Berry, "Dynamic Link Exchange Protocol (DLEP)", RFC 8175,
DOI 10.17487/RFC8175, June 2017, DOI 10.17487/RFC8175, June 2017,
<https://www.rfc-editor.org/info/rfc8175>. <https://www.rfc-editor.org/info/rfc8175>.
skipping to change at page 40, line 5 skipping to change at page 41, line 16
Perkins, "Registration Extensions for IPv6 over Low-Power Perkins, "Registration Extensions for IPv6 over Low-Power
Wireless Personal Area Network (6LoWPAN) Neighbor Wireless Personal Area Network (6LoWPAN) Neighbor
Discovery", RFC 8505, DOI 10.17487/RFC8505, November 2018, Discovery", RFC 8505, DOI 10.17487/RFC8505, November 2018,
<https://www.rfc-editor.org/info/rfc8505>. <https://www.rfc-editor.org/info/rfc8505>.
[RFC8629] Cheng, B. and L. Berger, Ed., "Dynamic Link Exchange [RFC8629] Cheng, B. and L. Berger, Ed., "Dynamic Link Exchange
Protocol (DLEP) Multi-Hop Forwarding Extension", RFC 8629, Protocol (DLEP) Multi-Hop Forwarding Extension", RFC 8629,
DOI 10.17487/RFC8629, July 2019, DOI 10.17487/RFC8629, July 2019,
<https://www.rfc-editor.org/info/rfc8629>. <https://www.rfc-editor.org/info/rfc8629>.
[RFC8691] Benamar, N., Härri, J., Lee, J., and T. Ernst, "Basic [RFC8684] Ford, A., Raiciu, C., Handley, M., Bonaventure, O., and C.
Support for IPv6 Networks Operating Outside the Context of Paasch, "TCP Extensions for Multipath Operation with
a Basic Service Set over IEEE Std 802.11", RFC 8691, Multiple Addresses", RFC 8684, DOI 10.17487/RFC8684, March
DOI 10.17487/RFC8691, December 2019, 2020, <https://www.rfc-editor.org/info/rfc8684>.
<https://www.rfc-editor.org/info/rfc8691>.
[RFC8757] Cheng, B. and L. Berger, Ed., "Dynamic Link Exchange [RFC8757] Cheng, B. and L. Berger, Ed., "Dynamic Link Exchange
Protocol (DLEP) Latency Range Extension", RFC 8757, Protocol (DLEP) Latency Range Extension", RFC 8757,
DOI 10.17487/RFC8757, March 2020, DOI 10.17487/RFC8757, March 2020,
<https://www.rfc-editor.org/info/rfc8757>. <https://www.rfc-editor.org/info/rfc8757>.
[RFC8899] Fairhurst, G., Jones, T., Tüxen, M., Rüngeler, I., and T.
Völker, "Packetization Layer Path MTU Discovery for
Datagram Transports", RFC 8899, DOI 10.17487/RFC8899,
September 2020, <https://www.rfc-editor.org/info/rfc8899>.
[RFC8928] Thubert, P., Ed., Sarikaya, B., Sethi, M., and R. Struik, [RFC8928] Thubert, P., Ed., Sarikaya, B., Sethi, M., and R. Struik,
"Address-Protected Neighbor Discovery for Low-Power and "Address-Protected Neighbor Discovery for Low-Power and
Lossy Networks", RFC 8928, DOI 10.17487/RFC8928, November Lossy Networks", RFC 8928, DOI 10.17487/RFC8928, November
2020, <https://www.rfc-editor.org/info/rfc8928>. 2020, <https://www.rfc-editor.org/info/rfc8928>.
[RFC8981] Gont, F., Krishnan, S., Narten, T., and R. Draves, [RFC8981] Gont, F., Krishnan, S., Narten, T., and R. Draves,
"Temporary Address Extensions for Stateless Address "Temporary Address Extensions for Stateless Address
Autoconfiguration in IPv6", RFC 8981, Autoconfiguration in IPv6", RFC 8981,
DOI 10.17487/RFC8981, February 2021, DOI 10.17487/RFC8981, February 2021,
<https://www.rfc-editor.org/info/rfc8981>. <https://www.rfc-editor.org/info/rfc8981>.
[RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", RFC 9000,
DOI 10.17487/RFC9000, May 2021,
<https://www.rfc-editor.org/info/rfc9000>.
[RFC9119] Perkins, C., McBride, M., Stanley, D., Kumari, W., and JC. [RFC9119] Perkins, C., McBride, M., Stanley, D., Kumari, W., and JC.
Zúñiga, "Multicast Considerations over IEEE 802 Wireless Zúñiga, "Multicast Considerations over IEEE 802 Wireless
Media", RFC 9119, DOI 10.17487/RFC9119, October 2021, Media", RFC 9119, DOI 10.17487/RFC9119, October 2021,
<https://www.rfc-editor.org/info/rfc9119>. <https://www.rfc-editor.org/info/rfc9119>.
8.2. Informative References
[RFC4821] Mathis, M. and J. Heffner, "Packetization Layer Path MTU
Discovery", RFC 4821, DOI 10.17487/RFC4821, March 2007,
<https://www.rfc-editor.org/info/rfc4821>.
[RFC6959] McPherson, D., Baker, F., and J. Halpern, "Source Address
Validation Improvement (SAVI) Threat Scope", RFC 6959,
DOI 10.17487/RFC6959, May 2013,
<https://www.rfc-editor.org/info/rfc6959>.
[RFC8899] Fairhurst, G., Jones, T., Tüxen, M., Rüngeler, I., and T.
Völker, "Packetization Layer Path MTU Discovery for
Datagram Transports", RFC 8899, DOI 10.17487/RFC8899,
September 2020, <https://www.rfc-editor.org/info/rfc8899>.
[I-D.ietf-intarea-ippl] [I-D.ietf-intarea-ippl]
Nordmark, E., "IP over Intentionally Partially Partitioned Nordmark, E., "IP over Intentionally Partially Partitioned
Links", Work in Progress, Internet-Draft, draft-ietf- Links", Work in Progress, Internet-Draft, draft-ietf-
intarea-ippl-00, 30 March 2017, intarea-ippl-00, 30 March 2017,
<https://www.ietf.org/archive/id/draft-ietf-intarea-ippl- <https://www.ietf.org/archive/id/draft-ietf-intarea-ippl-
00.txt>. 00.txt>.
[I-D.ietf-lisp-rfc6830bis] [I-D.ietf-lisp-rfc6830bis]
Farinacci, D., Fuller, V., Meyer, D., Lewis, D., and A. Farinacci, D., Fuller, V., Meyer, D., Lewis, D., and A.
Cabellos, "The Locator/ID Separation Protocol (LISP)", Cabellos, "The Locator/ID Separation Protocol (LISP)",
Work in Progress, Internet-Draft, draft-ietf-lisp- Work in Progress, Internet-Draft, draft-ietf-lisp-
rfc6830bis-36, 18 November 2020, rfc6830bis-38, 7 May 2022,
<https://www.ietf.org/archive/id/draft-ietf-lisp- <https://www.ietf.org/archive/id/draft-ietf-lisp-
rfc6830bis-36.txt>. rfc6830bis-38.txt>.
[I-D.templin-6man-aero] [I-D.templin-6man-aero]
Templin, F. L., "Automatic Extended Route Optimization Templin, F. L., "Automatic Extended Route Optimization
(AERO)", Work in Progress, Internet-Draft, draft-templin- (AERO)", Work in Progress, Internet-Draft, draft-templin-
6man-aero-40, 7 March 2022, 6man-aero-46, 25 April 2022,
<https://www.ietf.org/archive/id/draft-templin-6man-aero- <https://www.ietf.org/archive/id/draft-templin-6man-aero-
40.txt>. 46.txt>.
[I-D.templin-6man-omni] [I-D.templin-6man-omni]
Templin, F. L., "Transmission of IP Packets over Overlay Templin, F. L., "Transmission of IP Packets over Overlay
Multilink Network (OMNI) Interfaces", Work in Progress, Multilink Network (OMNI) Interfaces", Work in Progress,
Internet-Draft, draft-templin-6man-omni-55, 7 March 2022, Internet-Draft, draft-templin-6man-omni-61, 25 April 2022,
<https://www.ietf.org/archive/id/draft-templin-6man-omni- <https://www.ietf.org/archive/id/draft-templin-6man-omni-
55.txt>. 61.txt>.
[I-D.templin-ipwave-uam-its] [I-D.templin-ipwave-uam-its]
Templin, F. L., "Urban Air Mobility Implications for Templin, F. L., "Urban Air Mobility Implications for
Intelligent Transportation Systems", Work in Progress, Intelligent Transportation Systems", Work in Progress,
Internet-Draft, draft-templin-ipwave-uam-its-04, 4 January Internet-Draft, draft-templin-ipwave-uam-its-04, 4 January
2021, <https://www.ietf.org/archive/id/draft-templin- 2021, <https://www.ietf.org/archive/id/draft-templin-
ipwave-uam-its-04.txt>. ipwave-uam-its-04.txt>.
[I-D.templin-intarea-parcels] [I-D.templin-intarea-parcels]
Templin, F. L., "IP Parcels", Work in Progress, Internet- Templin, F. L., "IP Parcels", Work in Progress, Internet-
Draft, draft-templin-intarea-parcels-09, 10 February 2022, Draft, draft-templin-intarea-parcels-10, 29 March 2022,
<https://www.ietf.org/archive/id/draft-templin-intarea- <https://www.ietf.org/archive/id/draft-templin-intarea-
parcels-09.txt>. parcels-10.txt>.
[I-D.ietf-dmm-fpc-cpdp] [I-D.ietf-dmm-fpc-cpdp]
Matsushima, S., Bertz, L., Liebsch, M., Gundavelli, S., Matsushima, S., Bertz, L., Liebsch, M., Gundavelli, S.,
Moses, D., and C. E. Perkins, "Protocol for Forwarding Moses, D., and C. E. Perkins, "Protocol for Forwarding
Policy Configuration (FPC) in DMM", Work in Progress, Policy Configuration (FPC) in DMM", Work in Progress,
Internet-Draft, draft-ietf-dmm-fpc-cpdp-14, 22 September Internet-Draft, draft-ietf-dmm-fpc-cpdp-14, 22 September
2020, <https://www.ietf.org/archive/id/draft-ietf-dmm-fpc- 2020, <https://www.ietf.org/archive/id/draft-ietf-dmm-fpc-
cpdp-14.txt>. cpdp-14.txt>.
[I-D.thubert-6man-ipv6-over-wireless] [I-D.thubert-6man-ipv6-over-wireless]
Thubert, P., "IPv6 Neighbor Discovery on Wireless Thubert, P., "IPv6 Neighbor Discovery on Wireless
Networks", Work in Progress, Internet-Draft, draft- Networks", Work in Progress, Internet-Draft, draft-
thubert-6man-ipv6-over-wireless-11, 15 December 2021, thubert-6man-ipv6-over-wireless-11, 15 December 2021,
<https://www.ietf.org/archive/id/draft-thubert-6man-ipv6- <https://www.ietf.org/archive/id/draft-thubert-6man-ipv6-
over-wireless-11.txt>. over-wireless-11.txt>.
[I-D.ietf-madinas-mac-address-randomization]
Zuniga, J. C., Bernardos, C. J., and A. Andersdotter, "MAC
address randomization", Work in Progress, Internet-Draft,
draft-ietf-madinas-mac-address-randomization-01, 7 March
2022, <https://www.ietf.org/archive/id/draft-ietf-madinas-
mac-address-randomization-01.txt>.
[I-D.ietf-madinas-use-cases]
Henry, J. and Y. L. Lee, "Randomized and Changing MAC
Address Use Cases", Work in Progress, Internet-Draft,
draft-ietf-madinas-use-cases-01, 22 February 2022,
<https://www.ietf.org/archive/id/draft-ietf-madinas-use-
cases-01.txt>.
[I-D.jeong-ipwave-vehicular-neighbor-discovery]
Jeong, J. (., Shen, Y. (., Xiang, Z., and S. Cespedes,
"Vehicular Neighbor Discovery for IP-Based Vehicular
Networks", Work in Progress, Internet-Draft, draft-jeong-
ipwave-vehicular-neighbor-discovery-13, 21 February 2022,
<https://www.ietf.org/archive/id/draft-jeong-ipwave-
vehicular-neighbor-discovery-13.txt>.
[I-D.jeong-ipwave-vehicular-mobility-management]
Jeong, J. (., Mugabarigira, B. A., Shen, Y. (., and Z.
Xiang, "Vehicular Mobility Management for IP-Based
Vehicular Networks", Work in Progress, Internet-Draft,
draft-jeong-ipwave-vehicular-mobility-management-07, 21
February 2022, <https://www.ietf.org/archive/id/draft-
jeong-ipwave-vehicular-mobility-management-07.txt>.
[I-D.jeong-ipwave-security-privacy]
Jeong, J. (., Shen, Y. (., and J. Park, "Basic Support for
Security and Privacy in IP-Based Vehicular Networks", Work
in Progress, Internet-Draft, draft-jeong-ipwave-security-
privacy-05, 21 February 2022,
<https://www.ietf.org/archive/id/draft-jeong-ipwave-
security-privacy-05.txt>.
[DSRC] ASTM International, "Standard Specification for [DSRC] ASTM International, "Standard Specification for
Telecommunications and Information Exchange Between Telecommunications and Information Exchange Between
Roadside and Vehicle Systems - 5 GHz Band Dedicated Short Roadside and Vehicle Systems - 5 GHz Band Dedicated Short
Range Communications (DSRC) Medium Access Control (MAC) Range Communications (DSRC) Medium Access Control (MAC)
and Physical Layer (PHY) Specifications", and Physical Layer (PHY) Specifications",
ASTM E2213-03(2010), October 2010. ASTM E2213-03(2010), October 2010.
[EU-2008-671-EC] [EU-2008-671-EC]
European Union, "Commission Decision of 5 August 2008 on European Union, "Commission Decision of 5 August 2008 on
the Harmonised Use of Radio Spectrum in the 5875 - 5905 the Harmonised Use of Radio Spectrum in the 5875 - 5905
skipping to change at page 46, line 21 skipping to change at page 48, line 11
[Bitcoin] Nakamoto, S., "Bitcoin: A Peer-to-Peer Electronic Cash [Bitcoin] Nakamoto, S., "Bitcoin: A Peer-to-Peer Electronic Cash
System", URL: https://bitcoin.org/bitcoin.pdf, May 2009. System", URL: https://bitcoin.org/bitcoin.pdf, May 2009.
[Vehicular-BlockChain] [Vehicular-BlockChain]
Dorri, A., Steger, M., Kanhere, S., and R. Jurdak, Dorri, A., Steger, M., Kanhere, S., and R. Jurdak,
"BlockChain: A Distributed Solution to Automotive Security "BlockChain: A Distributed Solution to Automotive Security
and Privacy", IEEE Communications Magazine, Vol. 55, No. and Privacy", IEEE Communications Magazine, Vol. 55, No.
12, December 2017. 12, December 2017.
[FCC-ITS-Modification]
Federal Communications Commission, "Use of the 5.850-5.925
GHz Band, First Report and Order, Further Notice of
Proposed Rulemaking, and Order of Proposed Modification,
FCC 19-138", Available: https://www.fcc.gov/document/fcc-
modernizes-59-ghz-band-improve-wi-fi-and-automotive-
safety-0, November 2020.
Appendix A. Support of Multiple Radio Technologies for V2V Appendix A. Support of Multiple Radio Technologies for V2V
Vehicular networks may consist of multiple radio technologies such as Vehicular networks may consist of multiple radio technologies such as
DSRC and 5G V2X. Although a Layer-2 solution can provide support for DSRC and 5G V2X. Although a Layer-2 solution can provide support for
multihop communications in vehicular networks, the scalability issue multihop communications in vehicular networks, the scalability issue
related to multihop forwarding still remains when vehicles need to related to multihop forwarding still remains when vehicles need to
disseminate or forward packets toward multihop-away destinations. In disseminate or forward packets toward multihop-away destinations. In
addition, the IPv6-based approach for V2V as a network layer protocol addition, the IPv6-based approach for V2V as a network layer protocol
can accommodate multiple radio technologies as MAC protocols, such as can accommodate multiple radio technologies as MAC protocols, such as
DSRC and 5G V2X. Therefore, the existing IPv6 protocol can be DSRC and 5G V2X. Therefore, the existing IPv6 protocol can be
skipping to change at page 46, line 43 skipping to change at page 48, line 41
in order to support both wireless single-hop/multihop V2V in order to support both wireless single-hop/multihop V2V
communications and multiple radio technologies in vehicular networks. communications and multiple radio technologies in vehicular networks.
In such a way, vehicles can communicate with each other by V2V In such a way, vehicles can communicate with each other by V2V
communications to share either an emergency situation or road hazard communications to share either an emergency situation or road hazard
information in a highway having multiple kinds of radio technologies. information in a highway having multiple kinds of radio technologies.
Appendix B. Support of Multihop V2X Networking Appendix B. Support of Multihop V2X Networking
The multihop V2X networking can be supported by RPL (IPv6 Routing The multihop V2X networking can be supported by RPL (IPv6 Routing
Protocol for Low-Power and Lossy Networks) [RFC6550] and Overlay Protocol for Low-Power and Lossy Networks) [RFC6550] and Overlay
Multilink Network Interface (OMNI) [I-D.templin-6man-omni]. Multilink Network Interface (OMNI) [I-D.templin-6man-omni] with AERO
[I-D.templin-6man-aero] .
RPL defines an IPv6 routing protocol for low-power and lossy networks RPL defines an IPv6 routing protocol for low-power and lossy networks
(LLN), mostly designed for home automation routing, building (LLN), mostly designed for home automation routing, building
automation routing, industrial routing, and urban LLN routing. It automation routing, industrial routing, and urban LLN routing. It
uses a Destination-Oriented Directed Acyclic Graph (DODAG) to uses a Destination-Oriented Directed Acyclic Graph (DODAG) to
construct routing paths for hosts (e.g., IoT devices) in a network. construct routing paths for hosts (e.g., IoT devices) in a network.
The DODAG uses an objective function (OF) for route selection and The DODAG uses an objective function (OF) for route selection and
optimization within the network. A user can use different routing optimization within the network. A user can use different routing
metrics to define an OF for a specific scenario. RPL supports metrics to define an OF for a specific scenario. RPL supports
multipoint-to-point, point-to-multipoint, and point-to-point traffic, multipoint-to-point, point-to-multipoint, and point-to-point traffic,
and the major traffic flow is the multipoint-to-point traffic. For and the major traffic flow is the multipoint-to-point traffic. For
example, in a highway scenario, a vehicle may not access an RSU example, in a highway scenario, a vehicle may not access an IP-RSU
directly because of the distance of the DSRC coverage (up to 1 km). 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 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 a vehicle can take advantage of other vehicles as relay nodes to
reach the RSU. Also, RPL can be extended to support both multihop reach the IP-RSU. Also, RPL can be extended to support both multihop
V2V and V2X in the similar way. V2V and V2X in the similar way.
RPL is primarily designed to minimize the control plane activity, RPL is primarily designed to minimize the control plane activity,
which is the relative amount of routing protocol exchanges versus which is the relative amount of routing protocol exchanges versus
data traffic; this approach is beneficial for situations where the data traffic; this approach is beneficial for situations where the
power and bandwidth are scarce (e.g., an IoT LLN where RPL is power and bandwidth are scarce (e.g., an IoT LLN where RPL is
typically used today), but also in situations of high relative typically used today), but also in situations of high relative
mobility between the nodes in the network (also known as swarming, mobility between the nodes in the network (also known as swarming,
e.g., within a variable set of vehicles with a similar global motion, e.g., within a variable set of vehicles with a similar global motion,
or a variable set of drones flying toward the same direction). or a variable set of drones flying toward the same direction).
To reduce the routing exchanges, RPL leverages a Distance Vector (DV) To reduce the routing exchanges, RPL leverages a Distance Vector (DV)
approach, which does not need a global knowledge of the topology, and 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 only optimizes the routes to and from the root, allowing Peer-to-Peer
(P2P) paths to be stretched. Although RPL installs its routes (P2P) paths to be stretched. Although RPL installs its routes
proactively, it only maintains them lazily, that is, in reaction to proactively, it only maintains them lazily, that is, in reaction to
actual traffic, or as a slow background activity. Additionally, RPL actual traffic, or as a slow background activity. Additionally, RPL
leverages the concept of an objective function (called OF), which leverages the concept of an objective function (called OF), which
allows to adapt the activity of the routing protocol to use cases, allows adapting the activity of the routing protocol to use cases,
e.g., type, speed, and quality of the radios. RPL does not need e.g., type, speed, and quality of the radios. RPL does not need
converge, and provides connectivity to most nodes most of the time. converge, and provides connectivity to most nodes most of the time.
The default route toward the root is maintained aggressively and may The default route toward the root is maintained aggressively and may
change while a packet progresses without causing loops, so the packet change while a packet progresses without causing loops, so the packet
will still reach the root. There are two modes for routing in RPL 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 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 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 the graph informs the root with a single unicast packet flowing along
the default route, and the connectivity is restored immediately; this the default route, and the connectivity is restored immediately; this
mode is preferable for use cases where Internet connectivity is mode is preferable for use cases where Internet connectivity is
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Overlay Multilink Network Interfaces that are virtual interfaces Overlay Multilink Network Interfaces that are virtual interfaces
governing multiple physical network interfaces. OMNI supports governing multiple physical network interfaces. OMNI supports
multihop V2V communication between vehicles in multiple forwarding multihop V2V communication between vehicles in multiple forwarding
hops via intermediate vehicles with OMNI links. It also supports hops via intermediate vehicles with OMNI links. It also supports
multihop V2I communication between a vehicle and an infrastructure multihop V2I communication between a vehicle and an infrastructure
access point by multihop V2V communication. The OMNI interface access point by multihop V2V communication. The OMNI interface
supports an NBMA link model where multihop V2V and V2I communications supports an NBMA link model where multihop V2V and V2I communications
use each mobile node's ULAs without need for any DAD or MLD use each mobile node's ULAs without need for any DAD or MLD
Messaging. Messaging.
In OMNI protocol, each wireless media interface is configured with an In OMNI protocol, an OMNI virtual interface can have a ULA [RFC4193]
IPv6 Unique Local Address (ULA) [RFC4193] that is assured unique indeed, but wireless physical interfaces associated with the OMNI
within the vehicular network according to AERO/OMNI and [RFC5889]. virtual interface are using any prefix. The ULA supports both V2V
The ULA supports both V2V and V2I multihop forwarding within the and V2I multihop forwarding within the vehicular network (e.g., via a
vehicular network (e.g., via a VANET routing protocol) while each VANET routing protocol) while each vehicle can communicate with
vehicle can communicate with Internet correspondents using global Internet correspondents using global IPv6 addresses via OMNI
IPv6 addresses via OMNI interface encapsulation over the wireless interface encapsulation over the wireless interface.
interface.
For the control traffic overhead for running both vehicular ND and a For the control traffic overhead for running both vehicular ND and a
VANET routing protocol, the AERO/OMNI approach may avoid this issue VANET routing protocol, the AERO/OMNI approach may avoid this issue
by using MANET routing protocols only (i.e., no multicast of IPv6 ND by using MANET routing protocols only (i.e., no multicast of IPv6 ND
messaging) in the wireless underlay network while applying efficient messaging) in the wireless underlay network while applying efficient
unicast IPv6 ND messaging in the OMNI overlay on an as-needed basis unicast IPv6 ND messaging in the OMNI overlay on an as-needed basis
for router discovery and NUD. This greatly reduces the overhead for for router discovery and NUD. This greatly reduces the overhead for
VANET-wide multicasting while providing agile accommodation for VANET-wide multicasting while providing agile accommodation for
dynamic topology changes. dynamic topology changes.
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that are often much larger than the actual path MTU.) that are often much larger than the actual path MTU.)
Performance studies over the course of many decades have proven that Performance studies over the course of many decades have proven that
applications will see greater performance by sending smaller numbers applications will see greater performance by sending smaller numbers
of large packets (as opposed to larger numbers of small packets) even of large packets (as opposed to larger numbers of small packets) even
if fragmentation is needed. The OAL further supports even larger if fragmentation is needed. The OAL further supports even larger
packet sizes through the IP Parcels construct packet sizes through the IP Parcels construct
[I-D.templin-intarea-parcels] which provides "packets-in-packet" [I-D.templin-intarea-parcels] which provides "packets-in-packet"
encapsulation for a total size up to 4MB. Together, the OAL and IP encapsulation for a total size up to 4MB. Together, the OAL and IP
Parcels will provide a revolutionary new capability for greater Parcels will provide a revolutionary new capability for greater
efficiency in both mobile and fixed networks. efficiency in both mobile and fixed networks. On the other hand, due
to the high dynamics of vehicular networks, a high packet loss may
not be able to be avoided. The high packet loss on IP parcels can
simultaneously cause multiple TCP sessions to experience packet re-
transmissions, session time-out, or re-establishment of the sessions.
Other protocols such as MPTCP and QUIC may also experience the
similar issue. A mechanism for mitigating this issue in OAL and IP
Parcels should be considered.
Appendix E. Acknowledgments Appendix E. Acknowledgments
This work was supported by Institute of Information & Communications This work was supported by Institute of Information & Communications
Technology Planning & Evaluation (IITP) grant funded by the Korea Technology Planning & Evaluation (IITP) grant funded by the Korea
MSIT (Ministry of Science and ICT) (R-20160222-002755, Cloud based MSIT (Ministry of Science and ICT) (R-20160222-002755, Cloud based
Security Intelligence Technology Development for the Customized Security Intelligence Technology Development for the Customized
Security Service Provisioning). Security Service Provisioning).
This work was supported in part by the MSIT, Korea, under the ITRC This work was supported in part by the MSIT, Korea, under the ITRC
skipping to change at page 52, line 26 skipping to change at page 54, line 26
Republic of Korea, Phone: +82 31 299 4106, Fax: +82 31 290 7996, Republic of Korea, Phone: +82 31 299 4106, Fax: +82 31 290 7996,
EMail: chrisshen@skku.edu, URI: https://chrisshen.github.io EMail: chrisshen@skku.edu, URI: https://chrisshen.github.io
Michelle Wetterwald - Michelle Wetterwald -
FBConsulting, 21, Route de Luxembourg, Wasserbillig, Luxembourg FBConsulting, 21, Route de Luxembourg, Wasserbillig, Luxembourg
L-6633, Luxembourg, EMail: Michelle.Wetterwald@gmail.com L-6633, Luxembourg, EMail: Michelle.Wetterwald@gmail.com
Author's Address Author's Address
Jaehoon (Paul) Jeong (editor) Jaehoon Paul Jeong (editor)
Department of Computer Science and Engineering Department of Computer Science and Engineering
Sungkyunkwan University Sungkyunkwan University
2066 Seobu-Ro, Jangan-Gu 2066 Seobu-Ro, Jangan-Gu
Suwon Suwon
Gyeonggi-Do Gyeonggi-Do
16419 16419
Republic of Korea Republic of Korea
Phone: +82 31 299 4957 Phone: +82 31 299 4957
Email: pauljeong@skku.edu Email: pauljeong@skku.edu
URI: http://iotlab.skku.edu/people-jaehoon-jeong.php URI: http://iotlab.skku.edu/people-jaehoon-jeong.php
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