draft-ietf-ipwave-vehicular-networking-07.txt   draft-ietf-ipwave-vehicular-networking-08.txt 
IPWAVE Working Group J. Jeong, Ed. IPWAVE Working Group J. Jeong, Ed.
Internet-Draft Sungkyunkwan University Internet-Draft Sungkyunkwan University
Intended status: Informational November 4, 2018 Intended status: Informational March 24, 2019
Expires: May 8, 2019 Expires: September 25, 2019
IP Wireless Access in Vehicular Environments (IPWAVE): Problem Statement IP Wireless Access in Vehicular Environments (IPWAVE): Problem Statement
and Use Cases and Use Cases
draft-ietf-ipwave-vehicular-networking-07 draft-ietf-ipwave-vehicular-networking-08
Abstract Abstract
This document discusses the problem statement and use cases on IP- This document discusses the problem statement and use cases of IP-
based vehicular networks, which are considered a key component of based vehicular networking for Intelligent Transportation Systems
Intelligent Transportation Systems (ITS). The main scenarios of (ITS). The main scenarios of vehicular communications are vehicle-
vehicular communications are vehicle-to-vehicle (V2V), vehicle-to- to-vehicle (V2V), vehicle-to-infrastructure (V2I), and vehicle-to-
infrastructure (V2I), and vehicle-to-everything (V2X) communications. everything (V2X) communications. First, this document surveys use
First, this document surveys use cases using V2V, V2I, and V2X cases using V2V, V2I, and V2X networking. Second, it analyzes
networking. Second, it analyzes proposed protocols for IP-based proposed protocols for IP-based vehicular networking and highlights
vehicular networking and highlights the limitations and difficulties the limitations and difficulties found on those protocols. Third, it
found on those protocols. Third, it presents a problem exploration presents a problem exploration for key aspects in IP-based vehicular
for key aspects in IP-based vehicular networking, such as IPv6 networking, such as IPv6 Neighbor Discovery, Mobility Management, and
Neighbor Discovery, Mobility Management, and Security & Privacy. For Security & Privacy. For each key aspect, this document discusses a
each key aspect, this document discusses a problem statement to problem statement to evaluate the gap between the state-of-the-art
evaluate the gap between the state-of-the-art techniques and techniques and requirements in IP-based vehicular networking.
requirements in IP-based vehicular networking.
Status of This Memo Status of This Memo
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This Internet-Draft will expire on May 8, 2019. This Internet-Draft will expire on September 25, 2019.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. V2V . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1. V2V . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. V2I . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.2. V2I . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.3. V2X . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.3. V2X . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Analysis for Existing Protocols . . . . . . . . . . . . . . . 8 4. Analysis for Existing Protocols . . . . . . . . . . . . . . . 8
4.1. Existing Protocols for Vehicular Networking . . . . . . . 8 4.1. Existing Protocols for Vehicular Networking . . . . . . . 8
4.1.1. IPv6 over 802.11-OCB . . . . . . . . . . . . . . . . 8 4.1.1. IP Address Autoconfiguration . . . . . . . . . . . . 8
4.1.2. IP Address Autoconfiguration . . . . . . . . . . . . 8 4.1.2. Routing Protocol . . . . . . . . . . . . . . . . . . 9
4.1.3. Routing . . . . . . . . . . . . . . . . . . . . . . . 9 4.1.3. Mobility Management . . . . . . . . . . . . . . . . . 10
4.1.4. Mobility Management . . . . . . . . . . . . . . . . . 9 4.1.4. DNS Naming Service . . . . . . . . . . . . . . . . . 11
4.1.5. DNS Naming Service . . . . . . . . . . . . . . . . . 9 4.1.5. Service Discovery . . . . . . . . . . . . . . . . . . 12
4.1.6. Service Discovery . . . . . . . . . . . . . . . . . . 9 4.1.6. Security and Privacy . . . . . . . . . . . . . . . . 12
4.1.7. Security and Privacy . . . . . . . . . . . . . . . . 10 4.2. General Problems . . . . . . . . . . . . . . . . . . . . 13
4.2. General Problems . . . . . . . . . . . . . . . . . . . . 10 4.2.1. Vehicular Network Architecture . . . . . . . . . . . 14
4.2.1. Vehicular Network Architecture . . . . . . . . . . . 11 4.2.2. Latency . . . . . . . . . . . . . . . . . . . . . . . 19
4.2.2. Latency . . . . . . . . . . . . . . . . . . . . . . . 16 4.2.3. Security . . . . . . . . . . . . . . . . . . . . . . 20
4.2.3. Security . . . . . . . . . . . . . . . . . . . . . . 16 4.2.4. Pseudonym Handling . . . . . . . . . . . . . . . . . 20
4.2.4. Pseudonym Handling . . . . . . . . . . . . . . . . . 16 5. Problem Exploration . . . . . . . . . . . . . . . . . . . . . 20
5. Problem Exploration . . . . . . . . . . . . . . . . . . . . . 17 5.1. Neighbor Discovery . . . . . . . . . . . . . . . . . . . 20
5.1. Neighbor Discovery . . . . . . . . . . . . . . . . . . . 17 5.1.1. Link Model . . . . . . . . . . . . . . . . . . . . . 21
5.1.1. Link Model . . . . . . . . . . . . . . . . . . . . . 17 5.1.2. MAC Address Pseudonym . . . . . . . . . . . . . . . . 22
5.1.2. MAC Address Pseudonym . . . . . . . . . . . . . . . . 18 5.1.3. Prefix Dissemination/Exchange . . . . . . . . . . . . 22
5.1.3. Prefix Dissemination/Exchange . . . . . . . . . . . . 18 5.1.4. Routing . . . . . . . . . . . . . . . . . . . . . . . 22
5.1.4. Routing . . . . . . . . . . . . . . . . . . . . . . . 18 5.2. Mobility Management . . . . . . . . . . . . . . . . . . . 23
5.2. Mobility Management . . . . . . . . . . . . . . . . . . . 19 5.3. Security and Privacy . . . . . . . . . . . . . . . . . . 24
5.3. Security and Privacy . . . . . . . . . . . . . . . . . . 20 6. Security Considerations . . . . . . . . . . . . . . . . . . . 24
6. Security Considerations . . . . . . . . . . . . . . . . . . . 20 7. Informative References . . . . . . . . . . . . . . . . . . . 25
7. Informative References . . . . . . . . . . . . . . . . . . . 21 Appendix A. Relevant Topics to IPWAVE Working Group . . . . . . 33
Appendix A. Relevant Topics to IPWAVE Working Group . . . . . . 29 A.1. Vehicle Identity Management . . . . . . . . . . . . . . . 33
A.1. Vehicle Identity Management . . . . . . . . . . . . . . . 29 A.2. Multihop V2X . . . . . . . . . . . . . . . . . . . . . . 33
A.2. Multihop V2X . . . . . . . . . . . . . . . . . . . . . . 29 A.3. Multicast . . . . . . . . . . . . . . . . . . . . . . . . 33
A.3. Multicast . . . . . . . . . . . . . . . . . . . . . . . . 29 A.4. DNS Naming Services and Service Discovery . . . . . . . . 34
A.4. DNS Naming Services and Service Discovery . . . . . . . . 30 A.5. IPv6 over Cellular Networks . . . . . . . . . . . . . . . 34
A.5. IPv6 over Cellular Networks . . . . . . . . . . . . . . . 30 A.5.1. Cellular V2X (C-V2X) Using 4G-LTE . . . . . . . . . . 34
A.5.1. Cellular V2X (C-V2X) Using 4G-LTE . . . . . . . . . . 30 A.5.2. Cellular V2X (C-V2X) Using 5G . . . . . . . . . . . . 35
A.5.2. Cellular V2X (C-V2X) Using 5G . . . . . . . . . . . . 31
Appendix B. Changes from draft-ietf-ipwave-vehicular- Appendix B. Changes from draft-ietf-ipwave-vehicular-
networking-06 . . . . . . . . . . . . . . . . . . . 31 networking-07 . . . . . . . . . . . . . . . . . . . 35
Appendix C. Acknowledgments . . . . . . . . . . . . . . . . . . 31 Appendix C. Acknowledgments . . . . . . . . . . . . . . . . . . 35
Appendix D. Contributors . . . . . . . . . . . . . . . . . . . . 32 Appendix D. Contributors . . . . . . . . . . . . . . . . . . . . 36
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 34 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 38
1. Introduction 1. Introduction
Vehicular networking studies have mainly focused on driving safety, Vehicular networking studies have mainly focused on improving safety
driving efficiency, and entertainment in road networks. The Federal and efficiency, and also enabling entertainment in vehicular
Communications Commission (FCC) in the US allocated wireless channels networks. The Federal Communications Commission (FCC) in the US
for Dedicated Short-Range Communications (DSRC) [DSRC], service in allocated wireless channels for Dedicated Short-Range Communications
the Intelligent Transportation Systems (ITS) Radio Service in the (DSRC) [DSRC], service in the Intelligent Transportation Systems
5.850 - 5.925 GHz band (5.9 GHz band). DSRC-based wireless (ITS) Radio Service in the 5.850 - 5.925 GHz band (5.9 GHz band).
communications can support vehicle-to-vehicle (V2V), vehicle-to- DSRC-based wireless communications can support vehicle-to-vehicle
infrastructure (V2I), and vehicle-to-everything (V2X) networking. (V2V), vehicle-to-infrastructure (V2I), and vehicle-to-everything
Also, the European Union (EU) passed a decision to allocate radio (V2X) networking. Also, the European Union (EU) passed a decision to
spectrum for safety-related and non-safety-related applications of allocate radio spectrum for safety-related and non-safety-related
ITS with the frequency band of 5.875 - 5.905 GHz, which is called applications of ITS with the frequency band of 5.875 - 5.905 GHz,
Commission Decision 2008/671/EC [EU-2008-671-EC]. which is called Commission Decision 2008/671/EC [EU-2008-671-EC].
For direct inter-vehicular wireless connectivity, IEEE has amended For direct inter-vehicular wireless connectivity, IEEE has amended
WiFi standard 802.11 to enable driving safety services based on the WiFi standard 802.11 to enable driving safety services based on the
DSRC in terms of standards for the Wireless Access in Vehicular DSRC in terms of standards for the Wireless Access in Vehicular
Environments (WAVE) system. L1 and L2 issues are addressed in IEEE Environments (WAVE) system. The Physical Layer (L1) and Data Link
802.11p [IEEE-802.11p] for the PHY and MAC of the DSRC, while IEEE Layer (L2) issues are addressed in IEEE 802.11p [IEEE-802.11p] for
1609.2 [WAVE-1609.2] covers security aspects, IEEE 1609.3 the PHY and MAC of the DSRC, while IEEE 1609.2 [WAVE-1609.2] covers
[WAVE-1609.3] defines related services at network and transport security aspects, IEEE 1609.3 [WAVE-1609.3] defines related services
layers, and IEEE 1609.4 [WAVE-1609.4] specifies the multi-channel at network and transport layers, and IEEE 1609.4 [WAVE-1609.4]
operation. Note that IEEE 802.11p has been published as IEEE 802.11 specifies the multi-channel operation. Note that IEEE 802.11p was a
Outside the Context of a Basic Service Set (OCB) called IEEE separate standard, but was later enrolled into the base 802.11
802.11-OCB [IEEE-802.11-OCB] in 2012. standard (IEEE 802.11-2012) as IEEE 802.11 Outside the Context of a
Basic Service Set in 2012 [IEEE-802.11-OCB].
Along with these WAVE standards, IPv6 [RFC8200] and Mobile IP Along with these WAVE standards, IPv6 [RFC8200] and Mobile IP
protocols (e.g., MIPv4 [RFC5944] and MIPv6 [RFC6275]) can be applied protocols (e.g., MIPv4 [RFC5944], MIPv6 [RFC6275], and Proxy MIPv6
(or easily modified) to vehicular networks. In Europe, ETSI has (PMIPv6) [RFC5213][RFC5844]) can be applied (or easily modified) to
standardized a GeoNetworking (GN) protocol [ETSI-GeoNetworking] and a vehicular networks. In Europe, ETSI has standardized a GeoNetworking
protocol adaptation sub-layer from GeoNetworking to IPv6 (GN) protocol [ETSI-GeoNetworking] and a protocol adaptation sub-
[ETSI-GeoNetwork-IP]. Note that a GN protocol is useful to route an layer from GeoNetworking to IPv6 [ETSI-GeoNetwork-IP]. Note that a
event or notification message to vehicles around a geographic GN protocol is useful to route an event or notification message to
position, such as an acciendent area in a roadway. In addition, ISO vehicles around a geographic position, such as an acciendent area in
has approved a standard specifying the IPv6 network protocols and a roadway. In addition, ISO has approved a standard specifying the
services to be used for Communications Access for Land Mobiles (CALM) IPv6 network protocols and services to be used for Communications
[ISO-ITS-IPv6]. Access for Land Mobiles (CALM) [ISO-ITS-IPv6].
This document discusses problem statements and use cases related to This document discusses problem statements and use cases related to
IP-based vehicular networking for Intelligent Transportation Systems IP-based vehicular networking for Intelligent Transportation Systems
(ITS), which is denoted as IP Wireless Access in Vehicular (ITS), which is denoted as IP Wireless Access in Vehicular
Environments (IPWAVE). First, it surveys the use cases for using Environments (IPWAVE). First, it surveys the use cases for using
V2V, V2I, and V2X networking in the ITS. Second, for literature V2V, V2I, and V2X networking in the ITS. Second, for literature
review, it analyzes proposed protocols for IP-based vehicular review, it analyzes proposed protocols for IP-based vehicular
networking and highlights the limitations and difficulties found on networking and highlights the limitations and difficulties found on
those protocols. Third, for problem statement, it presents a problem those protocols. Third, for problem statement, it presents a problem
exploration with key aspects in IPWAVE, such as IPv6 Neighbor exploration with key aspects in IPWAVE, such as IPv6 Neighbor
skipping to change at page 4, line 32 skipping to change at page 4, line 29
Multihop V2X Communications, Multicast, DNS Naming Services, Service Multihop V2X Communications, Multicast, DNS Naming Services, Service
Discovery, and IPv6 over Cellular Networks. Therefore, with the Discovery, and IPv6 over Cellular Networks. Therefore, with the
problem statement, this document will open a door to develop key problem statement, this document will open a door to develop key
protocols for IPWAVE that will be essential to IP-based vehicular protocols for IPWAVE that will be essential to IP-based vehicular
networks. networks.
2. Terminology 2. Terminology
This document uses the following definitions: This document uses the following definitions:
o WAVE: Acronym for "Wireless Access in Vehicular Environments"
[WAVE-1609.0].
o DMM: Acronym for "Distributed Mobility Management" o DMM: Acronym for "Distributed Mobility Management"
[RFC7333][RFC7429]. [RFC7333][RFC7429].
o Road-Side Unit (RSU): A node that has physical communication o LiDAR: Acronym for "Light Detection and Ranging". It is a
devices (e.g., DSRC, Visible Light Communication, 802.15.4, LTE- scanning device to measure a distance to an object by emitting
V2X, etc.) for wireless communications with vehicles and is also pulsed laser light and measuring the reflected pulsed light.
connected to the Internet as a router or switch for packet
forwarding. An RSU is typically deployed on the road
infrastructure, either at an intersection or in a road segment,
but may also be located in car parking area.
o On-Board Unit (OBU): A node that has a DSRC device for wireless o Mobility Anchor (MA): A node that maintains IP addresses and
communications with other OBUs and RSUs, and may be connected to mobility information of vehicles in a road network to support
in-vehicle devices or networks. An OBU is mounted on a vehicle. their address autoconfiguration and mobility management with a
It is assumed that a radio navigation receiver (e.g., Global binding table. It has end-to-end connections with RSUs under its
Positioning System (GPS)) is included in a vehicle with an OBU for control.
efficient navigation.
o Vehicle Detection Loop (or Loop Detector): An inductive device o On-Board Unit (OBU): A node that has (e.g., IEEE 802.11-OCB and
used for detecting vehicles passing or arriving at a certain Cellular V2X (C-V2X) [TS-23.285-3GPP]) for wireless communications
point, for instance approaching a traffic light or in motorway with other OBUs and RSUs, and may be connected to in-vehicle
traffic. The relatively crude nature of the loop's structure devices or networks. An OBU is mounted on a vehicle. It is
means that only metal masses above a certain size are capable of assumed that a radio navigation receiver (e.g., Global Positioning
triggering the detection. System (GPS)) is included in a vehicle with an OBU for efficient
navigation.
o Mobility Anchor (MA): A node that maintains IP addresses and o OCB: Acronym for "Outside the Context of a Basic Service Set"
mobility information of vehicles in a road network to support the [IEEE-802.11-OCB].
address autoconfiguration and mobility management of them. It has
end-to-end connections with RSUs under its control. It maintains
a DAD table having the IP addresses of the vehicles moving within
the communication coverage of its RSUs.
o Vehicular Cloud: A cloud infrastructure for vehicular networks, o Road-Side Unit (RSU): A node that has physical communication
having compute nodes, storage nodes, and network nodes. devices (e.g., IEEE 802.11-OCB and C-V2X) for wireless
communications with vehicles and is also connected to the Internet
as a router or switch for packet forwarding. An RSU is typically
deployed on the road infrastructure, either at an intersection or
in a road segment, but may also be located in car parking area.
o Traffic Control Center (TCC): A node that maintains road o Traffic Control Center (TCC): A node that maintains road
infrastructure information (e.g., RSUs, traffic signals, and loop infrastructure information (e.g., RSUs, traffic signals, and loop
detectors), vehicular traffic statistics (e.g., average vehicle detectors), vehicular traffic statistics (e.g., average vehicle
speed and vehicle inter-arrival time per road segment), and speed and vehicle inter-arrival time per road segment), and
vehicle information (e.g., a vehicle's identifier, position, vehicle information (e.g., a vehicle's identifier, position,
direction, speed, and trajectory as a navigation path). TCC is direction, speed, and trajectory as a navigation path). TCC is
included in a vehicular cloud for vehicular networks. included in a vehicular cloud for vehicular networks.
o Vehicular Cloud: A cloud infrastructure for vehicular networks,
having compute nodes, storage nodes, and network nodes.
o Vehicle Detection Loop (or Loop Detector): An inductive device
used for detecting vehicles passing or arriving at a certain
point, for instance approaching a traffic light or in motorway
traffic. The relatively crude nature of the loop's structure
means that only metal masses above a certain size are capable of
triggering the detection.
o V2I2P: Acronym for "Vehicle to Infrastructure to Pedestrian".
o V2I2V: Acronym for "Vehicle to Infrastructure to Vehicle".
o WAVE: Acronym for "Wireless Access in Vehicular Environments"
[WAVE-1609.0].
3. Use Cases 3. Use Cases
This section provides use cases of V2V, V2I, and V2X networking. The This section provides use cases of V2V, V2I, and V2X networking. The
use cases of the V2X networking exclude the ones of the V2V and V2I use cases of the V2X networking exclude the ones of the V2V and V2I
networking, but include Vehicle-to-Pedestrian (V2P) and Vehicle-to- networking, but include Vehicle-to-Pedestrian (V2P) and Vehicle-to-
Device (V2D). Device (V2D).
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
skipping to change at page 6, line 18 skipping to change at page 6, line 24
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, such automatic safety action plan, which considers three situations, such
as the Line-of-Sight unsafe, Non-Line-of-Sight unsafe and safe as the Line-of-Sight unsafe, Non-Line-of-Sight unsafe and safe
situations. This action plan can be performed among vehicles through situations. This action plan can be performed among vehicles through
V2V networking. V2V networking.
Cooperative Adaptive Cruise Control (CACC) [CA-Cruise-Control] helps Cooperative Adaptive Cruise Control (CACC) [CA-Cruise-Control] helps
vehicles to adapt their speed autonomously through V2V communication vehicles to adapt their speed autonomously through V2V communication
among vehicles according to the mobility of their predecessor and among vehicles according to the mobility of their predecessor and
successor vehicles in an urban roadway or a highway. CACC can help successor vehicles in an urban roadway or a highway. Thus, CACC can
adjacent vehicles to efficiently adjust their speed in a cascade way help adjacent vehicles to efficiently adjust their speed in an
through V2V networking. interactive way through V2V networking in order to avoid collision.
Platooning [Truck-Platooning] allows a series of vehicles (e.g., Platooning [Truck-Platooning] allows a series of vehicles (e.g.,
trucks) to move together with a very short inter-distance. Trucks trucks) to move together with a very short inter-distance. Trucks
can use V2V communication in addition to forward sensors in order to can use V2V communication in addition to forward sensors in order to
maintain constant clearance between two consecutive vehicles at very maintain constant clearance between two consecutive vehicles at very
short gaps (from 3 meters to 10 meters). This platooning can short gaps (from 3 meters to 10 meters). This platooning can
maximize the throughput of vehicular traffic in a highway and reduce maximize the throughput of vehicular traffic in a highway and reduce
the gas consumption because the leading vehicle can help the the gas consumption because the leading vehicle can help the
following vehicles to experience less air resistance. following vehicles to experience less air resistance.
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o Navigation service; o Navigation service;
o Energy-efficient speed recommendation service; o Energy-efficient speed recommendation service;
o Accident notification service. o Accident notification service.
A navigation service, such as the Self-Adaptive Interactive A navigation service, such as the Self-Adaptive Interactive
Navigation Tool (called SAINT) [SAINT], using V2I networking Navigation Tool (called SAINT) [SAINT], using V2I networking
interacts with TCC for the large-scale/long-range road traffic interacts with TCC for the large-scale/long-range road traffic
optimization and can guide individual vehicles for appropriate optimization and can guide individual vehicles for appropriate
navigation paths in real time. The enhanced SAINT (called SAINT+) navigation paths in real time. The enhanced version of SAINT
[SAINTplus] can give the fast moving paths for emergency vehicles [SAINTplus] can give the fast moving paths to emergency vehicles
(e.g., ambulance and fire engine) toward accident spots while (e.g., ambulance and fire engine) to let them reach accident spots
providing other vehicles with efficient detour paths. while providing other vehicles with efficient detour paths.
A TCC can recommend an energy-efficient speed to a vehicle driving in A TCC can recommend an energy-efficient speed to a vehicle driving in
different traffic environments. [Fuel-Efficient] studies fuel- different traffic environments. [Fuel-Efficient] studies fuel-
efficient route and speed plans for platooned trucks. efficient route and speed plans for platooned trucks.
The emergency communication between accident vehicles (or emergency The emergency communication between accident vehicles (or emergency
vehicles) and TCC can be performed via either RSU or 4G-LTE networks. vehicles) and TCC can be performed via either RSU or 4G-LTE networks.
The First Responder Network Authority (FirstNet) [FirstNet] is The First Responder Network Authority (FirstNet) [FirstNet] is
provided by the US government to establish, operate, and maintain an provided by the US government to establish, operate, and maintain an
interoperable public safety broadband network for safety and security interoperable public safety broadband network for safety and security
skipping to change at page 8, line 13 skipping to change at page 8, line 22
for collision avoidance. for collision avoidance.
4. Analysis for Existing Protocols 4. Analysis for Existing Protocols
4.1. Existing Protocols for Vehicular Networking 4.1. Existing Protocols for Vehicular Networking
We describe some currently existing protocols and proposed solutions We describe some currently existing protocols and proposed solutions
with respect to the following aspects that are relevant and essential with respect to the following aspects that are relevant and essential
for vehicular networking: for vehicular networking:
o IPv6 over 802.11-OCB;
o IP address autoconfiguration; o IP address autoconfiguration;
o Routing; o Routing protocol;
o Mobility management; o Mobility management;
o DNS naming service; o DNS naming service;
o Service discovery; o Service discovery;
o Security and privacy. o Security and privacy.
4.1.1. IPv6 over 802.11-OCB 4.1.1. IP Address Autoconfiguration
For IPv6 packets transporting over IEEE 802.11-OCB,
[IPv6-over-802.11-OCB] specifies several details, such as Maximum
Transmission Unit (MTU), frame format, link-local address, address
mapping for unicast and multicast, stateless autoconfiguration, and
subnet structure. Especially, an Ethernet Adaptation (EA) layer is
in charge of transforming some parameters between IEEE 802.11 MAC
layer and IPv6 network layer, which is located between IEEE
802.11-OCB's logical link control layer and IPv6 network layer.
4.1.2. IP Address Autoconfiguration
For IP address autoconfiguration, Fazio et al. proposed a vehicular For IP address autoconfiguration, Fazio et al. proposed a vehicular
address configuration (VAC) scheme using DHCP where elected leader- address configuration (VAC) scheme using DHCP where elected leader-
vehicles provide unique identifiers for IP address configurations in vehicles provide unique identifiers for IP address configurations in
vehicles [Address-Autoconf]. Kato et al. proposed an IPv6 address vehicles [Address-Autoconf]. Kato et al. proposed an IPv6 address
assignment scheme using lane and position information assignment scheme using lane and position information
[Address-Assignment]. Baldessari et al. proposed an IPv6 scalable [Address-Assignment]. Baldessari et al. proposed an IPv6 scalable
address autoconfiguration scheme called GeoSAC for vehicular networks address autoconfiguration scheme called GeoSAC for vehicular networks
[GeoSAC]. Wetterwald et al. conducted for heterogeneous vehicular [GeoSAC]. Wetterwald et al. conducted for heterogeneous vehicular
networks (i.e., employing multiple access technologies) a networks (i.e., employing multiple access technologies) a
comprehensive study of the cross-layer identities management, which comprehensive study of the cross-layer identity management, which
constitutes a fundamental element of the ITS architecture constitutes a fundamental element of the ITS architecture
[Identity-Management]. [Identity-Management].
4.1.3. Routing A server-based address autoconfiguration such as VAC
[Address-Autoconf] takes some delay for a vehicle to join a new
cluster (i.e., a connected VANET) and communicate with neighboring
vehicles. This delay may prevent vehicles from exchaning safety
messages with each other in a prompty way. It will be good for a
vehicle to maintain its IP address even when it joins another
cluster. A geographical-position-based address autoconfiguration,
such as a prefix allocation per lane [Address-Assignment] and a
prefix allocation per geographic region [GeoSAC], causes the frequent
change of a vehicle's IP address and requires the DAD for the
uniqueness test of a new IP address. This is significant overhead
for high-speed moving vehicles. It will be efficient for a vehicle
to be able to use its IP address while moving across the clusters and
geographical regions. For the cross-layer identity management with
multiple wireless interfaces [Identity-Management], it will be
necessary to maintain an upper-layer session (e.g., TCP session) of a
vehicle with multiple IP addresses corresponing to the multiple
wireless interfaces.
For routing, Tsukada et al. presented a work that aims at combining 4.1.2. Routing Protocol
IPv6 networking and a Car-to-Car Network routing protocol (called
C2CNet) proposed by the Car2Car Communication Consortium (C2C-CC),
which is an architecture using a geographic routing protocol
[VANET-Geo-Routing]. Abrougui et al. presented a gateway discovery
scheme for VANET, called Location-Aided Gateway Advertisement and
Discovery (LAGAD) mechanism [LAGAD].
4.1.4. Mobility Management For vehicular routing, Abboud et al. proposed a cluster-based routing
[Cluster-Based-Routing]. Vehicles construct clusters along with
their location and speed information for fast data dissemination
among the clusters. They consist of cluster headers, cluster
gateways and cluster members for intra-cluster and inter-cluster
communications. Tsukada et al. presented a work that aims at
combining IPv6 networking and a Car-to-Car Network (called C2CNet)
routing protocol proposed by the Car-to-Car Communication Consortium
(C2C-CC). Note that C2CNet is the network layer of the C2C-CC
communication system and uses a geographic routing protocol for
vehicular networks [VANET-Geo-Routing]. Abrougui et al. presented a
gateway discovery scheme for vehicles to access the Internet via a
gateway, called Location-Aided Gateway Advertisement and Discovery
(LAGAD) mechanism [LAGAD]. A vehicle (as a packet source) multihop
away from a gateway can discover the gateway and deliver its packets
to the gateway through the packet forwarding of intermediate vehicles
(as relay vehicles) in a connected VANET. Those intermediate
vehicles are located between the packet source vehicle and the
gateway.
For data packet routing in vehicular networks, multihop V2V and
multihop V2I communications are required. For multihop V2V
communications within a connected VANET, a cluster-based routing like
[Cluster-Based-Routing] can play a role of efficient data forwarding
through a virtual backbone of cluster headers and cluster gateways.
For this, an efficient cluster formation is performed through sharing
the mobility information (e.g., position, direction, and speed) of
vehicles. But the pure VANET-based clustering will cause significant
control messages and need some delay for cluster formation, so
vehicles can perform clustering through infrastructure nodes (e.g.,
RSUs and base stations) via cellular links, which guarantees always-
network-connection.
For multihop V2I communications, a gateway discovery scheme like
LAGAD [LAGAD] can be used through a connected VANET having a
connection with an Internet gateway. However, this reactive gateway
discovery causes much control messages for the discovery and need
some delay until a packet source vehicle can transmit its packets
toward the gateway. Thus, a proactive gateway discovery is required
over a connected VANET where vehicles share routes towards gateways
(e.g., distance vector information to gateways) in a proactive
manner.
4.1.3. Mobility Management
For mobility management, Chen et al. tackled the issue of network For mobility management, Chen et al. tackled the issue of network
fragmentation in VANET environments [IP-Passing-Protocol] by fragmentation in VANET environments [IP-Passing-Protocol] by
proposing a protocol that can postpone the time to release IP proposing a protocol that can postpone the time to release IP
addresses to the DHCP server and select a faster way to get the addresses to the DHCP server and select a faster way to get the
vehicle's new IP address, when the vehicle density is low or the vehicle's new IP address, when the vehicle density is low or the
speeds of vehicles are highly variable. Nguyen et al. proposed a speeds of vehicles are highly variable. Nguyen et al. proposed a
hybrid centralized-distributed mobility management called H-DMM to hybrid centralized-distributed mobility management called H-DMM to
support highly mobile vehicles [H-DMM]. [NEMO-LMS] proposed an support the mobility of high-speed mobile vehicles, which is based on
architecture to enable IP mobility for moving networks using a both DMM and PMIPv6 [H-DMM]. They also proposed a hybrid
network-based mobility scheme based on PMIPv6. Chen et al. proposed centralized-distributed mobility management for network mobility
a network mobility protocol to reduce handoff delay and maintain called H-NEMO to support the efficient mobility of mobile nodes and
Internet connectivity to moving vehicles in a highway [NEMO-VANET]. mobile routers between different subnets, which is based on both DMM
Lee et al. proposed P-NEMO, which is a PMIPv6-based IP mobility and PMIPv6 [H-NEMO].
management scheme to maintain the Internet connectivity at the
vehicle as a mobile network, and provides a make-before-break [NEMO-LMS] proposed an architecture to enable IP mobility for moving
networks using a network-based mobility scheme based on PMIPv6. Chen
et al. proposed a network mobility protocol to reduce handoff delay
and maintain Internet connectivity to moving vehicles in a highway
[NEMO-VANET]. Lee et al. proposed P-NEMO, which is a PMIPv6-based IP
mobility management scheme to maintain the Internet connectivity at
the vehicle as a mobile network, and provides a make-before-break
mechanism when vehicles switch to a new access network mechanism when vehicles switch to a new access network
[PMIP-NEMO-Analysis]. Peng et al. proposed a novel mobility [PMIP-NEMO-Analysis]. Peng et al. proposed a novel mobility
management scheme for integration of VANET and fixed IP networks management scheme for integration of VANET and fixed IP networks
[VNET-MM]. Nguyen et al. extended their previous works on a [VNET-MM]. This scheme uses both a road network layout and the
vehicular adapted DMM considering a Software-Defined Networking (SDN) wireless coverage of multiple base stations in order to improve the
architecture [SDN-DMM]. connectivity of vehicles to the Internet and decrease the overhead of
mobility management. Nguyen et al. extended their previous works
(i.e., H-DMM [H-DMM] and H-NEMO [H-NEMO]) on a vehicular DMM by using
a Software-Defined Networking (SDN) architecture, which separates the
control plane and the data plane in network functionality [SDN-DMM].
4.1.5. DNS Naming Service A vehicle can have an internal network for its in-vehicle devices and
passengers' mobile devices. In this case, vehicular networks need to
support not only the host mobility for the vehicle, but also the
network mobility of such an internet network within the vehicle. The
current mobility management schemes, such as [H-DMM] and [H-NEMO],
are not enough to support both the host mobility and network mobility
in an efficient way. An efficient mobility management scheme can
take advantage of a vehicle's mobility information (e.g., position,
direction, and speed) and partial or full trajectory (i.e., a
navigation path in a road network) in order to perform operations for
mobility management proactively. For this proactive mobility
management, an SDN-based mobility management scheme like [SDN-DMM]
will be promising because SDN controllers can proactively set up
forwarding tables for traffic flows of vehicles with their mobility
and trajectory information.
4.1.4. DNS Naming Service
For DNS naming service, Multicast DNS (mDNS) [RFC6762] allows devices For DNS naming service, Multicast DNS (mDNS) [RFC6762] allows devices
in one-hop communication range to resolve each other's DNS name into in one-hop communication range to resolve each other's DNS name into
the corresponding IP address in multicast. DNS Name the corresponding IP address in multicast. DNS Name
Autoconfiguration (DNSNA) [ID-DNSNA] proposes a DNS naming service Autoconfiguration (DNSNA) [ID-DNSNA] proposes a DNS naming service
for Internet-of-Things (IoT) devices in a large-scale network. for Internet-of-Things (IoT) devices in a large-scale network.
4.1.6. Service Discovery A DNS name resolution service needs to support DNS name resolution
for in-vehicle devices and passengers' mobile devices within a
vehicle's internal network, which can be called intra-vehicle DNS
name resolution. Also, it needs to support DNS name resolution
between devices (e.g., cooperative cruise control device) existing in
different vehicles, which can be called inter-vehicle DNS name
resolution. In addition, it need to support DNS name resolution in
hosts or servers as corresponding nodes in the Internet, which can be
called global DNS name resolution.
For the intra-vehicle DNS name resolution and inter-vehicle DNS name
resolution, both mDNS [RFC6762] and DNSNA [ID-DNSNA] can be used, but
they perform DNS name resolution in a reactive way. That is, when a
DNS query is given by a querier, it will be multicasted to devices
through mDNS or be unicasted to a dedicated DNS server through DNSNA,
respectively.
For the inter-vehicle DNS name resolution in fast-moving vehicles, a
proactive DNS resolution can be performed by the help of an RSU that
collects the DNS information of vehicles and disseminate it to
vehicles under its coverage.
For the global DNS name resolution, a vehicle can use an RSU's DNS
server (or a DNS server close to an RSU in the wired network) to
perform a DNS resolution for the sake of the vehicle's device during
its travel. When the DNS resolution is finished by the RSU's DNS
server, the DNS server can forward the DNS resolution result to the
vehicle through the current RSU providing the vehicle with the
Internet connectivity.
4.1.5. Service Discovery
To discover instances of a demanded service in vehicular networks, To discover instances of a demanded service in vehicular networks,
DNS-based Service Discovery (DNS-SD) [RFC6763] with either DNSNA DNS-based Service Discovery (DNS-SD) [RFC6763] with either DNSNA
[ID-DNSNA] or mDNS [RFC6762] provides vehicles with service discovery [ID-DNSNA] or mDNS [RFC6762] provides vehicles with service discovery
by using standard DNS queries. Vehicular ND [ID-Vehicular-ND] by using standard DNS queries. Vehicular ND [ID-Vehicular-ND]
proposes an extension of IPv6 ND for the prefix and service discovery proposes an extension of IPv6 ND for the prefix and service discovery
with new ND options [ID-VND-Discovery]. Note that a DNS query for with new ND options.
service discovery is unicasted in DNSNA, but it is multicasted in
For vehicular networks, DNSNA can use a dedicated DNS server residing
in an RSU or close to an RSU in the wired network [ID-DNSNA]. In
this case, in-vehicle devices can register their services (e.g.,
cooperative cruise control service and navigation service) into the
DNS server. When the DNS server can receive a service discovery
query from vehicles via an RSU, it can resolve it quickly for them.
In DNSNA, these DNS query and response messages are delivered in
unicast rather than multicast, so the wireless channel will be
utilized efficiently for DNS resolution including service discovery.
Thus, DNSNA will provide a more efficient service discovery to
vehicles in a high-vehicle-density environment than mDNS [RFC6762]
and Vehicular ND [ID-Vehicular-ND]. This is because a DNS query for
service discovery is unicasted by DNSNA, but it is multicasted by
both mDNS and Vehicular ND. both mDNS and Vehicular ND.
4.1.7. Security and Privacy In a V2V scenario such as the case where a dedicated DNS server in an
RSU is not available for the registration and sharing of service
information, Vehicular ND can provide vehicles with rapid service
discovery by letting vehicles proactively advertise their service
information with Neighbor Advertisement (NA) messages. Thus,
considering both V2I and V2V scenarios, an efficient service
discovery scheme can be designed.
4.1.6. Security and Privacy
For security and privacy, Fernandez et al. proposed a secure For security and privacy, Fernandez et al. proposed a secure
vehicular IPv6 communication scheme using Internet Key Exchange vehicular IPv6 communication scheme using Internet Key Exchange
version 2 (IKEv2) and Internet Protocol Security (IPsec) version 2 (IKEv2) and Internet Protocol Security (IPsec) for
[Securing-VCOMM]. Moustafa et al. proposed a security scheme vehiculer networks. This scheme provides the secure communication
providing authentication, authorization, and accounting (AAA) channel between a home agent and a mobile router to support the
services in vehicular networks [VNET-AAA]. network mobility of a vehicle's internal network [Securing-VCOMM].
Moustafa et al. proposed a security scheme providing authentication,
authorization, and accounting (AAA) services in vehicular networks
[VNET-AAA]. The vehicular networks consist of VANETs as a front end
and an access network as a back end via an access point. The
security scheme provides vehicles with an efficient AAA service for
the network connectivity during their movement in the road network.
Security services in vehicular networks need to support an efficient
AAA for the accommodation of only valid vehicles and a secure
communication with IKEv2 and IPsec between vehicles or between a
vehicle and the corresponding node in the Internet. For the
efficiency, these security services need to take advantage of a
vehicular network architecture having a TCC and RSUs as well as a
vehicle's mobility and trajectory information.
4.2. General Problems 4.2. General Problems
This section describes a possible vehicular network architecture for This section describes a possible vehicular network architecture for
V2V, V2I, and V2X communications. Then it analyzes the limitations V2V, V2I, and V2X communications. Then it analyzes the limitations
of the current protocols for vehicular networking. of the current protocols for vehicular networking.
Traffic Control Center in Vehicular Cloud Traffic Control Center in Vehicular Cloud
*-----------------------------------------* *-----------------------------------------*
* * * *
* +----------------+ * * +----------------+ *
* | Mobility Anchor| * * | Mobility Anchor| *
* +----------------+ * * +----------------+ *
* ^ * * ^ *
* | * * | *
*--------------------v--------------------* *--------------------v--------------------*
^ ^ ^ ^ ^ ^
| | | | | |
+------------------ | -------------|-------------+ +------------------+ | | |
| v v | | v | v v v
| +--------+ Ethernet +--------+ | | +--------+ | +--------+ Ethernet +--------+ +--------+
| | RSU1 |<----------->| RSU2 |<---------->| RSU3 | | | RSU1 |<-------->| RSU2 |<---------->| RSU3 |
| +--------+ +--------+ | | +--------+ | +--------+ +--------+ +--------+
| ^ ^ ^ | | ^ | ^ ^ ^
| : : : | | : | : : :
| V2I : : V2I V2I : | | V2I : | +--------------------------------------+ +------------------+
| v v v | | v | | : V2I V2I : | | V2I : |
| +--------+ +--------+ +--------+ | | +--------+ | | v v | | v |
| |Vehicle1|===> |Vehicle2|===> |Vehicle3|===>| | |Vehicle4|===>| +--------+ | +--------+ +--------+ | | +--------+ |
| | |<....>| |<....>| | | | | | | |Vehicle1|===> |Vehicle2|===> |Vehicle3|===> | | |Vehicle4|===>|
| +--------+ V2V +--------+ V2V +--------+ | | +--------+ | | |<...>| |<........>| | | | | | |
| | | | +--------+ V2V +--------+ V2V +--------+ | | +--------+ |
+-------------------------------------------------+ +------------------+ | | | |
Subnet1 Subnet2 +--------------------------------------+ +------------------+
Subnet1 Subnet2
<----> Wired Link <....> Wireless Link ===> Moving Direction <----> Wired Link <....> Wireless Link ===> Moving Direction
Figure 1: A Vehicular Network Architecture for V2I and V2V Networking Figure 1: A Vehicular Network Architecture for V2I and V2V Networking
4.2.1. Vehicular Network Architecture 4.2.1. Vehicular Network Architecture
Figure 1 shows a possible architecture for V2I and V2V networking in Figure 1 shows an architecture for V2I and V2V networking in a road
a road network. It is assumed that RSUs as routers and vehicles with network. As shown in this figure, RSUs as routers and vehicles with
OBU have wireless media interfaces (e.g., IEEE 802.11-OCB, LTE Uu and OBU have wireless media interfaces for VANET. Also, it is assumed
Device-to-Device (D2D) (also known as PC5 [TS-23.285-3GPP]), that such the wireless media interfaces are autoconfigured with a
Bluetooth, and Light Fidelity (Li-Fi)) for V2I and V2V communication. global IPv6 prefix (e.g., 2001:DB8:1:1::/64) to support both V2V and
Also, it is assumed that such the wireless media interfaces are V2I networking.
autoconfigured with a global IPv6 prefix (e.g., 2001:DB8:1:1::/64) to
support both V2V and V2I networking. Three RSUs (RSU1, RSU2, and Especially, for IPv6 packets transporting over IEEE 802.11-OCB,
RSU3) are deployed in the road network and are connected to a [IPv6-over-802.11-OCB] specifies several details, such as Maximum
Vehicular Cloud through the Internet. A Traffic Control Center (TCC) Transmission Unit (MTU), frame format, link-local address, address
is connected to the Vehicular Cloud for the management of RSUs and mapping for unicast and multicast, stateless autoconfiguration, and
vehicles in the road network. A Mobility Anchor (MA) is located in subnet structure. Especially, an Ethernet Adaptation (EA) layer is
the TCC as its key component for the mobility management of vehicles. in charge of transforming some parameters between IEEE 802.11 MAC
Two vehicles (Vehicle1 and Vehicle2) are wirelessly connected to layer and IPv6 network layer, which is located between IEEE
RSU1, and one vehicle (Vehicle3) is wirelessly connected to RSU2. 802.11-OCB's logical link control layer and IPv6 network layer. This
The wireless networks of RSU1 and RSU2 belong to a multi-link subnet IPv6 over 802.11-OCB can be used for both V2V and V2I in IP-based
(denoted as Subnet1) with the same network prefix. Thus, these three vehicular networks.
vehicles are within the same subnet. On the other hand, another
vehicle (Vehicle4) is wireless connected to RSU4, belonging to In Figure 1, three RSUs (RSU1, RSU2, and RSU3) are deployed in the
another subnet (denoted as Subnet2). That is, the first three road network and are connected to a Vehicular Cloud through the
vehicles (i.e., Vehicle1, Vehicle2, and Vehicle3) and the last Internet. A Traffic Control Center (TCC) is connected to the
vehicle (i.e., Vehicle4) are located in the two different subnets. Vehicular Cloud for the management of RSUs and vehicles in the road
Vehicle1 can communicate with Vehicle2 via V2V communication, and network. A Mobility Anchor (MA) is located in the TCC as its key
Vehicle2 can communicate with Vehicle3 via V2V communication because component for the mobility management of vehicles. Two vehicles
they are within the same subnet along their IPv6 addresses, which are (Vehicle1 and Vehicle2) are wirelessly connected to RSU1, and one
based on the same prefix. On the other hand, Vehicle3 can vehicle (Vehicle3) is wirelessly connected to RSU2. The wireless
communicate with Vehicle4 via RSU2 and RSU3 employing V2I (i.e., networks of RSU1 and RSU2 belong to a multi-link subnet (denoted as
V2I2V) communication because they are within the two different Subnet1) with the same network prefix. Thus, these three vehicles
subnets along with their IPv6 addresses, which are based on the two are within the same subnet. On the other hand, another vehicle
different prefixes. (Vehicle4) is wireless connected to RSU4, belonging to another subnet
(denoted as Subnet2). That is, the first three vehicles (i.e.,
Vehicle1, Vehicle2, and Vehicle3) and the last vehicle (i.e.,
Vehicle4) are located in the two different subnets.
In wireless subnets in vehicular networks (e.g., Subnet 1 and Subnet
2 in Figure 1), vehicles can construct a connected VANET (as an
arbitrary graph topology) and can communicate with each other via V2V
communication. Vehicle1 can communicate with Vehicle2 via V2V
communication, and Vehicle2 can communicate with Vehicle3 via V2V
communication because they are within the same subnet along their
IPv6 addresses, which are based on the same prefix. On the other
hand, Vehicle3 can communicate with Vehicle4 via RSU2 and RSU3
employing V2I (i.e., V2I2V) communication because they are within the
two different subnets along with their IPv6 addresses, which are
based on the two different prefixes.
In vehicular networks, unidirectional links exist and must be In vehicular networks, unidirectional links exist and must be
considered for wireless communications. Also, in the vehicular considered for wireless communications. Also, in the vehicular
networks, control plane must be separated from data plane for networks, control plane must be separated from data plane for
efficient mobility management and data forwarding using Software- efficient mobility management and data forwarding using Software-
Defined Networking (SDN) [SDN-DMM]. ID/Pseudonym change for privacy Defined Networking (SDN) [SDN-DMM]. The mobility information of a
requires a lightweight DAD. IP tunneling over the wireless link GPS receiver mounted in its vehicle (e.g., trajectory, position,
should be avoided for performance efficiency. The mobility speed, and direction) can be used for the accommodation of mobility-
information of a mobile (e.g., vehicle-mounted) device through a GPS aware proactive protocols. Vehicles can use the TCC as their Home
receiver in its vehicle, such as trajectory, position, speed, and Network having a home agent for mobility management as in MIPv6
direction, can be used by the mobile device and infrastructure nodes [RFC6275] and PMIPv6 [RFC5213], so the TCC maintains the mobility
(e.g., TCC and RSU) for the accommodation of mobility-aware proactive information of vehicles for location management. Also, IP tunneling
protocols. Vehicles can use the TCC as their Home Network having a over the wireless link should be avoided for performance efficiency.
home agent for mobility management as in MIPv6 [RFC6275] and Proxy
Mobile IPv6 (PMIPv6) [RFC5213], so the TCC maintains the mobility
information of vehicles for location management.
Cespedes et al. proposed a vehicular IP in WAVE called VIP-WAVE for Cespedes et al. proposed a vehicular IP in WAVE called VIP-WAVE for
I2V and V2I networking [VIP-WAVE]. The standard WAVE does not I2V and V2I networking [VIP-WAVE]. The standard WAVE does not
support both seamless communications for Internet services and multi- support both seamless communications for Internet services and multi-
hop communications between a vehicle and an infrastructure node hop communications between a vehicle and an infrastructure node
(e.g., RSU), either. To overcome these limitations of the standard (e.g., RSU), either. To overcome these limitations of the standard
WAVE, VIP-WAVE enhances the standard WAVE by the following three WAVE, VIP-WAVE enhances the standard WAVE by the following three
schemes: (i) an efficient mechanism for the IPv6 address assignment schemes:
and DAD, (ii) on-demand IP mobility based on PMIPv6 [RFC5213], and
(iii) one-hop and two-hop communications for I2V and V2I networking. 1. An efficient mechanism for the IPv6 address assignment and DAD
2. An on-demand IP mobility management based on PMIPv6 [RFC5213]
3. One-hop and two-hop communication scheme for V2I networking
Note that VIP-WAVE supports at most two-hop V2I communication for
simple forwarding operations in VANET. This is because the multi-hop
V2I communication with more than two hops requires an additional
VANET routing protocol. Such a multi-hop V2I communication will be
required for vehicles in a highway with sparsely deployed RSUs in
order to provide them with the Internet connectivity via V2I.
Baccelli et al. provided an analysis of the operation of IPv6 as it Baccelli et al. provided an analysis of the operation of IPv6 as it
has been described by the IEEE WAVE standards 1609 [IPv6-WAVE]. This has been described by the IEEE WAVE standards 1609 [IPv6-WAVE]. This
analysis confirms that the use of the standard IPv6 protocol stack in analysis confirms that the use of the standard IPv6 protocol stack in
WAVE is not sufficient. It recommends that the IPv6 addressing WAVE is not sufficient. It recommends that the IPv6 addressing
assignment should follow considerations for ad-hoc link models, assignment should follow considerations for ad-hoc link models,
defined in [RFC5889] for nodes' mobility and link variability. defined in [RFC5889] for nodes' mobility and link variability.
However, this ad-hoc link model is not clearly defined to support the
efficient V2V and V2I for vehicles with a wireless interface
configured with an IPv6 address.
Petrescu et al. proposed the joint IP networking and radio Petrescu et al. proposed the joint IP networking and radio
architecture for V2V and V2I communication in [Joint-IP-Networking]. architecture for V2V and V2I communication in [Joint-IP-Networking].
The proposed architecture considers an IP topology in a similar way The radio architecture uses Wi-Fi for wireless link rather than IEEE
as a radio link topology, in the sense that an IP subnet would 802.11-OCB. The proposed architecture considers an IP topology in a
correspond to the range of 1-hop vehicular communication. This similar way as a radio link topology, in the sense that an IP subnet
would correspond to the range of 1-hop vehicular communication. This
architecture defines three types of vehicles: Leaf Vehicle, Range architecture defines three types of vehicles: Leaf Vehicle, Range
Extending Vehicle, and Internet Vehicle. Extending Vehicle, and Internet Vehicle. Leaf Vehicle is like a
vehicle with OBU and has one external WiFi interface along with an
MR. This MR supports the network mobility of a user's mobile device
and in-vehicle devices in the vehicle's internal network. Range
Extending Vehicles has two external Wi-Fi interfaces to connect two
Wi-Fi subnets of cars in a train. Internet Vehicle has one Wi-Fi
interface for a car's subnet and one Wireless Metropolitan Area
Network (WMAN) interface for the Internet connectivity. However,
this architecture is not suitable for vehicles with a small size and
with a wireless interface for V2V and V2I in vehicular links.
+----------------+ 4.2.1.1. V2I-based Internetworking
(*)<........>(*) +----->| Vehicular Cloud|
2001:DB8:1:1::/64 | | | +----------------+ This section discusses the internetworking between a vehicle's moving
network and an RSU's fixed network via V2I communication.
+-----------------+
(*)<........>(*) +----->| Vehicular Cloud |
2001:DB8:1:1::/64 | | | +-----------------+
+------------------------------+ +---------------------------------+ +------------------------------+ +---------------------------------+
| v | | v v | | v | | v v |
| .-------. .------. .-------. | | .-------. .------. .-------. | | +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ |
| | Host1 | |RDNSS1| |Router1| | | |Router3| |RDNSS2| | Host3 | | | | Host1 | | DNS1 | |Router1| | | |Router3| | DNS2 | | Host3 | |
| ._______. .______. ._______. | | ._______. .______. ._______. | | +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ |
| ^ ^ ^ | | ^ ^ ^ | | ^ ^ ^ | | ^ ^ ^ |
| | | | | | | | | | | | | | | | | | | |
| v v v | | v 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 | |Router2| | | |Router4| |Server1|...|ServerN| | | | Host2 | |Router2| | | |Router4| |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 (Moving Network1) RSU1 (Fixed Network1) Vehicle1 (Moving Network1) RSU1 (Fixed Network1)
<----> Wired Link <....> Wireless Link (*) Antenna <----> Wired Link <....> Wireless Link (*) Antenna
Figure 2: Internetworking between Vehicle Network and RSU Network Figure 2: Internetworking between Vehicle Network and RSU Network
4.2.1.1. V2I-based Internetworking
This section discusses the internetworking between a vehicle's moving
network and an RSU's fixed network via V2I communication.
As shown in Figure 2, the vehicle's moving network and the RSU's As shown in Figure 2, the vehicle's moving network and the RSU's
fixed network are self-contained networks having multiple subnets and fixed network are self-contained networks having multiple subnets and
having an edge router for the communication with another vehicle or having an edge router for the communication with another vehicle or
RSU. The method of prefix assignment for each subnet inside the RSU. Internetworking between two internal networks via V2I
vehicle's mobile network and the RSU's fixed network is out of scope communication requires an exchange of network prefix and other
for this document. Internetworking between two internal networks via
V2I communication requires an exchange of network prefix and other
parameters through a prefix discovery mechanism, such as ND-based parameters through a prefix discovery mechanism, such as ND-based
prefix discovery [ID-VND-Discovery]. For the ND-based prefix prefix discovery [ID-Vehicular-ND]. For the ND-based prefix
discovery, network prefixs and parameters should be registered into a discovery, network prefixs and parameters should be registered into a
vehicle's router and an RSU router with an external network interface vehicle's router and an RSU router with an external network interface
in advance. in advance.
The network parameter discovery collects networking information for The network parameter discovery collects networking information for
an IP communication between a vehicle and an RSU or between two an IP communication between a vehicle and an RSU or between two
neighboring vehicles, such as link layer, MAC layer, and IP layer neighboring vehicles, such as link layer, MAC layer, and IP layer
information. The link layer information includes wireless link layer information. The link layer information includes wireless link layer
parameters, such as wireless media (e.g., IEEE 802.11-OCB, LTE Uu and parameters, such as wireless media (e.g., IEEE 802.11-OCB and LTE-
D2D, Bluetooth, and LiFi) and a transmission power level. Note that V2X) and a transmission power level. The MAC layer information
LiFi is a technology for light-based wireless communication between includes the MAC address of an external network interface for the
devices in order to transmit both data and position. The MAC layer internetworking with another vehicle or RSU. The IP layer
information includes the MAC address of an external network interface
for the internetworking with another vehicle or RSU. The IP layer
information includes the IP address and prefix of an external network information includes the IP address and prefix of an external network
interface for the internetworking with another vehicle or RSU. interface for the internetworking with another vehicle or RSU.
Once the network parameter discovery and prefix exchange operations Once the network parameter discovery and prefix exchange operations
have been performed, packets can be transmitted between the vehicle's have been performed, packets can be transmitted between the vehicle's
moving network and the RSU's fixed network. DNS services should be moving network and the RSU's fixed network. DNS services should be
supported to enable name resolution for hosts or servers residing supported to enable name resolution for hosts or servers residing
either in the vehicle's moving network or the RSU's fixed network. either in the vehicle's moving network or the RSU's fixed network.
It is assumed that the DNS names of in-vehicle devices and their It is assumed that the DNS names of in-vehicle devices and their
service names are registered into a DNS server (i.e., recursive DNS service names are registered into a DNS server in a vehicle or an
server called RDNSS) in a vehicle or an RSU, as shown in Figure 2. RSU, as shown in Figure 2. For service discovery, those DNS names
For service discovery, those DNS names and service names can be and service names can be advertised to neighboring vehicles through
advertised to neighboring vehicles through either DNS-based service either DNS-based service discovery mechanisms
discovery mechanisms [RFC6762][RFC6763][ID-DNSNA] and ND-based [RFC6762][RFC6763][ID-DNSNA] and ND-based service discovery
service discovery [ID-Vehicular-ND][ID-VND-Discovery]. For the ND- [ID-Vehicular-ND]. For the ND-based service discovery, service names
based service discovery, service names should be registered into a should be registered into a vehicle's router and an RSU router with
vehicle's router and an RSU router with an external network interface an external network interface in advance. For this service
in advance. Refer to Section 4.1.5 and Section 4.1.6 for detailed discovery, each vehicle and each RSU should have its dedicated DNS
information. For these DNS services, an RDNSS within each internal server within its internal network, respectively, as shown in
network of a vehicle or RSU can be used for the hosts or servers. Figure 2.
Figure 2 shows internetworking between the vehicle's moving network Figure 2 shows internetworking between the vehicle's moving network
and the RSU's fixed network. There exists an internal network and the RSU's fixed network. There exists an internal network
(Moving Network1) inside Vehicle1. Vehicle1 has the DNS Server (Moving Network1) inside Vehicle1. Vehicle1 has the DNS Server
(RDNSS1), the two hosts (Host1 and Host2), and the two routers (DNS1), the two hosts (Host1 and Host2), and the two routers (Router1
(Router1 and Router2). There exists another internal network (Fixed and Router2). There exists another internal network (Fixed Network1)
Network1) inside RSU1. RSU1 has the DNS Server (RDNSS2), one host inside RSU1. RSU1 has the DNS Server (DNS2), one host (Host3), the
(Host3), the two routers (Router3 and Router4), and the collection of two routers (Router3 and Router4), and the collection of servers
servers (Server1 to ServerN) for various services in the road (Server1 to ServerN) for various services in the road networks, such
networks, such as the emergency notification and navigation. as the emergency notification and navigation. Vehicle1's Router1
Vehicle1's Router1 (called mobile router) and RSU1's Router3 (called (called mobile router) and RSU1's Router3 (called fixed router) use
fixed router) use 2001:DB8:1:1::/64 for an external link (e.g., DSRC) 2001:DB8:1:1::/64 for an external link (e.g., DSRC) for I2V
for I2V networking. networking.
4.2.1.2. V2V-based Internetworking
This section discusses the internetworking between the moving
networks of two neighboring vehicles via V2V communication.
(*)<..........>(*) (*)<..........>(*)
2001:DB8:1:1::/64 | | 2001:DB8:1:1::/64 | |
+------------------------------+ +---------------------------------+ +------------------------------+ +------------------------------+
| v | | v | | v | | v |
| .-------. .------. .-------. | | .-------. .------. .-------. | | +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ |
| | Host1 | |RDNSS1| |Router1| | | |Router5| |RDNSS3| | Host4 | | | | Host1 | | DNS1 | |Router1| | | |Router5| | DNS3 | | Host4 | |
| ._______. .______. ._______. | | ._______. .______. ._______. | | +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ |
| ^ ^ ^ | | ^ ^ ^ | | ^ ^ ^ | | ^ ^ ^ |
| | | | | | | | | | | | | | | | | | | |
| v v v | | v 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 | |Router2| | | |Router6| | Host5 | | | | Host2 | |Router2| | | |Router6| | Host5 | |
| ._______. ._______. | | ._______. ._______. | | +-------+ +-------+ | | +-------+ +-------+ |
| ^ ^ | | ^ ^ | | ^ ^ | | ^ ^ |
| | | | | | | | | | | | | | | |
| 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 (Moving Network1) Vehicle2 (Moving Network2) Vehicle1 (Moving Network1) Vehicle2 (Moving Network2)
<----> Wired Link <....> Wireless Link (*) Antenna <----> Wired Link <....> Wireless Link (*) Antenna
Figure 3: Internetworking between Two Vehicle Networks Figure 3: Internetworking between Two Vehicle Networks
4.2.1.2. V2V-based Internetworking
This section discusses the internetworking between the moving
networks of two neighboring vehicles via V2V communication.
Figure 3 shows internetworking between the moving networks of two Figure 3 shows internetworking between the moving networks of two
neighboring vehicles. There exists an internal network (Moving neighboring vehicles. There exists an internal network (Moving
Network1) inside Vehicle1. Vehicle1 has the DNS Server (RDNSS1), the Network1) inside Vehicle1. Vehicle1 has the DNS Server (DNS1), the
two hosts (Host1 and Host2), and the two routers (Router1 and two hosts (Host1 and Host2), and the two routers (Router1 and
Router2). There exists another internal network (Moving Network2) Router2). There exists another internal network (Moving Network2)
inside Vehicle2. Vehicle2 has the DNS Server (RDNSS3), the two hosts inside Vehicle2. Vehicle2 has the DNS Server (DNS3), the two hosts
(Host4 and Host5), and the two routers (Router5 and Router6). (Host4 and Host5), and the two routers (Router5 and Router6).
Vehicle1's Router1 (called mobile router) and Vehicle2's Router5 Vehicle1's Router1 (called mobile router) and Vehicle2's Router5
(called mobile router) use 2001:DB8:1:1::/64 for an external link (called mobile router) use 2001:DB8:1:1::/64 for an external link
(e.g., DSRC) for V2V networking. (e.g., DSRC) for V2V networking.
The differences between IPWAVE (including Vehicular Ad Hoc Networks
(VANET)) and Mobile Ad Hoc Networks (MANET) are as follows:
o IPWAVE is not power-constrained operation;
o Traffic can be sourced or sinked outside of IPWAVE;
o IPWAVE shall support both distributed and centralized operations;
o No "sleep" period operation is required for energy saving.
4.2.2. Latency 4.2.2. Latency
The communication delay (i.e., latency) between two vehicular nodes The communication delay (i.e., latency) between two vehicles should
(vehicle and RSU) should be bounded to a certain threshold. For IP- be bounded to a certain threshold (e.g., 500 ms) for collision-
based safety applications (e.g., context-aware navigation, adaptive avoidance message exchange [CASD]. For IP-based safety applications
cruise control, and platooning) in vehicular network, this bounded (e.g., context-aware navigation, adaptive cruise control, and
data delivery is critical. The real implementations for such platooning) in vehicular network, this bounded data delivery is
applications are not available, so the feasibility of IP-based safety critical. The real implementations for such applications are not
applications is not tested yet. available yet. Thus, the feasibility of IP-based safety applications
is not tested yet in the real world.
4.2.3. Security 4.2.3. Security
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 safety applications, the cooperation among vehicles is hackers. For safety applications, the cooperation 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) to make driving be unsafe. (e.g., location, speed, and direction) to make driving be unsafe.
Sybil attack, which tries to illude a vehicle with multiple false Sybil attack, which tries to illude a vehicle with multiple false
identities, disturbs a vehicle in taking a safe maneuver. identities, disturbs a vehicle in taking a safe maneuver. This sybil
Applications on IP-based vehicular networking, which are resilient to attack should be prevented through the cooperation between good
such a sybil attack, are not developed and tested yet. vehicles and RSUs. Applications on IP-based vehicular networking,
which are resilient to such a sybil attack, are not developed and
tested yet.
4.2.4. Pseudonym Handling 4.2.4. Pseudonym Handling
For the protection of drivers' privacy, pseudonym for a vehicle's For the protection of drivers' privacy, the pseudonym of a MAC
network interface should be used, with the help of which the address of a vehicle's network interface should be used, with the
interface's identifier can be changed periodically. Such a pseudonym help of which the MAC address can be changed periodically. The
affects an IPv6 address based on the network interface's identifier, pseudonym of a MAC address affects an IPv6 address based on the MAC
and a transport-layer (e.g., TCP) session with an IPv6 address pair. address, and a transport-layer (e.g., TCP) session with an IPv6
The pseudonym handling is not implemented and tested yet for address pair. However, the pseudonym handling is not implemented and
applications on IP-based vehicular networking. tested yet for applications on IP-based vehicular networking.
5. Problem Exploration 5. Problem Exploration
This section discusses key topics for IPWAVE WG, such as neighbor This section discusses key topics for IPWAVE WG, such as neighbor
discovery, mobility management, and security & privacy. discovery, mobility management, and security & privacy.
5.1. Neighbor Discovery 5.1. Neighbor Discovery
Neighbor Discovery (ND) [RFC4861] is a core part of the IPv6 protocol Neighbor Discovery (ND) [RFC4861] is a core part of the IPv6 protocol
suite. This section discusses the need for modifying ND for use with suite. This section discusses the need for modifying ND for use with
vehicular networking (e.g., V2V, V2I, and V2X). The vehicles are vehicular networking (e.g., V2V, V2I, and V2X). The vehicles are
moving fast within the communication coverage of a vehicular node moving fast within the communication coverage of a vehicular node
(e.g., vehicle and RSU). The external wireless link between two (e.g., vehicle and RSU). The external wireless link between two
vehicular nodes can be used for vehicular networking, as shown in vehicular nodes can be used for vehicular networking, as shown in
Figure 2 and Figure 3. Figure 2 and Figure 3.
ND time-related parameters such as router lifetime and Neighbor ND time-related parameters such as router lifetime and Neighbor
Advertisement (NA) interval should be adjusted for high-speed Advertisement (NA) interval should be adjusted for high-speed
vehicles and vehicle density. As vehicles move faster, the NA vehicles and vehicle density. As vehicles move faster, the NA
interval should decrease for the NA messages to reach the neighboring interval should decrease (e.g., from 1 sec to 0.5 sec) for the NA
vehicles promptly. Also, as vehicle density is higher, the NA messages to reach the neighboring vehicles promptly. Also, as
interval should increase for the NA messages to reduce collision vehicle density is higher, the NA interval should increase (e.g.,
from 0.5 sec to 1 sec) for the NA messages to reduce collision
probability with other NA messages. probability with other NA messages.
5.1.1. Link Model 5.1.1. Link Model
IPv6 protocols work under certain assumptions for the link model that IPv6 protocols work under certain assumptions for the link model that
do not necessarily hold in a vehicular wireless link [VIP-WAVE]. For do not necessarily hold in a vehicular wireless link [VIP-WAVE]. For
instance, some IPv6 protocols assume symmetry in the connectivity instance, some IPv6 protocols assume symmetry in the connectivity
among neighboring interfaces. However, interference and different among neighboring interfaces. However, interference and different
levels of transmission power may cause unidirectional links to appear levels of transmission power may cause unidirectional links to appear
in vehicular wireless links. As a result, a new vehicular link model in vehicular wireless links. As a result, a new vehicular link model
is required for the vehicular wireless link. is required for a dynamically changing vehicular wireless link.
There is a relationship between a link and prefix, besides the There is a relationship between a link and prefix, besides the
different scopes that are expected from the link-local and global different scopes that are expected from the link-local and global
types of IPv6 addresses. In an IPv6 link, it is assumed that all types of IPv6 addresses. In an IPv6 link, it is assumed that all
interfaces which are configured with the same subnet prefix and with interfaces which are configured with the same subnet prefix and with
on-link bit set can communicate with each other on an IP link or on-link bit set can communicate with each other on an IP link or
extended IP links via ND proxy. Note that a subnet prefix can be extended IP links via ND proxy. Note that a subnet prefix can be
used by spanning multiple links as a multi-link subnet [RFC6775]. used by spanning multiple links into a multi-link subnet with an
Also, note that IPv6 Stateless Address Autoconfiguration can be extended subnet concept [RFC6775]. Also, note that IPv6 Stateless
performed in the multiple links where each of them is not assigned Address Autoconfiguration (SLAAC) can be performed in the multiple
with a unique subnet prefix, that is, all of them are configured with links where each of them is not assigned with a unique subnet prefix,
the same subnet prefix [RFC4861][RFC4862]. A vehicular link model that is, all of them are configured with the same subnet prefix
needs to consider a multi-hop VANET over a multi-link subnet. Such a [RFC4861][RFC4862].
VANET is usually a multi-link subnet consisting of multiple vehicles
interconnected by wireless communication range. Such a subnet has a A vehicular link model needs to consider a multi-hop V2V (or V2I)
highly dynamic topology over time due to node mobility. over a multi-link subnet as shown in Figure 1. In this figure,
vehicles in Subnet1 having RSU1 and RSU2 construct a multi-link
subnet called Subnet1 with VANETs and RSUs. Vehicle1 and Vehicle3
can communicate with each other via multi-hop V2V or multi-hop V2I2V.
When two vehicles (e.g., Vehicle1 and Vehicle3 in Figure 1) are
connected in a VANET, they can communicate with each other via VANET
rather than RSUs. On the other hand, when two vehicles (e.g.,
Vehicle1 and Vehicle3) are far away from the communication range in
separate VANETs and under two different RSUs, they can communicate
with each other through the relay of RSUs via V2I2V.
Thus, IPv6 ND should be extended into a Vehicular Neighbor Discovey Thus, IPv6 ND should be extended into a Vehicular Neighbor Discovey
(VND) [ID-Vehicular-ND] to support the concept of an IPv6 link (VND) [ID-Vehicular-ND] to support the concept of an IPv6 link
corresponding to an IPv6 prefix even in a multi-link subnet corresponding to an IPv6 prefix even in a multi-link subnet
consisting of multiple vehicles and RSUs that are interconnected with consisting of multiple vehicles and RSUs that are interconnected with
wireless communication range in IP-based vehicular networks. wireless communication range in IP-based vehicular networks.
5.1.2. MAC Address Pseudonym 5.1.2. MAC Address Pseudonym
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
should be updated. For the continuity of an end-to-end (E2E) should be updated, and the uniqueness of the address should be
transport-layer (e.g., TCP, UDP, and SCTP) session, with a mobility performed through the DAD procedure. For vehicular networks with
management scheme (e.g., MIPv6 and PMIPv6), the new IP address for high-mobility, this DAD should be performed efficiently with minimum
the transport-layer session should be notified to an appropriate end overhead.
point, and the packets of the session should be forwarded to their
destinations with the changed network interface identifier and IPv6 For the continuity of an end-to-end (E2E) transport-layer (e.g., TCP,
address. UDP, and SCTP) session, with a mobility management scheme (e.g.,
MIPv6 and PMIPv6), the new IP address for the transport-layer session
can be notified to an appropriate end point, and the packets of the
session should be forwarded to their destinations with the changed
network interface identifier and IPv6 address. This mobiliy
management overhead for pseudonyms should be minimized for efficient
operations in vehicular networks having lots of vehicles.
5.1.3. Prefix Dissemination/Exchange 5.1.3. Prefix Dissemination/Exchange
A vehicle and an RSU can have their internal network, as shown in A vehicle and an RSU can have their internal network, as shown in
Figure 2 and Figure 3. In this case, nodes in within the internal Figure 2 and Figure 3. In this case, nodes in within the internal
networks of two vehicular nodes (e.g., vehicle and RSU) want to networks of two vehicular nodes (e.g., vehicle and RSU) want to
communicate with each other. For this communication on the wireless communicate with each other. For this communication on the wireless
link, the network prefix dissemination or exchange is required. It link, the network prefix dissemination or exchange is required. It
is assumed that a vehicular node has an external network interface is assumed that a vehicular node has an external network interface
and its internal network. The legacy IPv6 ND [RFC4861] needs to be and its internal network, as shown in Figure 2 and Figure 3. The
extended to a vehicular ND (VND) [ID-Vehicular-ND] for the vehicular ND (VND) [ID-Vehicular-ND] can support the communication
communication between the internal-network nodes (e.g., an in-vehicle between the internal-network nodes (e.g., an in-vehicle device in a
device in a vehicle and a server in an RSU) of vehicular nodes by vehicle and a server in an RSU) of vehicular nodes with a vehicular
letting each of them know the other side's prefix with a new ND prefix information option. Thus, this ND extension for routing
option [ID-VND-Discovery]. Thus, this ND extension for routing
functionality can reduce control traffic for routing in vehicular functionality can reduce control traffic for routing in vehicular
networks without an additional vehicular ad hoc routing protocol networks without a vehicular ad hoc routing protocol (e.g., AODV
[VANET-Geo-Routing]. [RFC3561] and OLSRv2 [RFC7181]).
5.1.4. Routing 5.1.4. Routing
For multihop V2V communications in a multi-link subnet (as a For multihop V2V communications in a multi-link subnet (as a
connected VANET), a vehicular ad hoc routing protocol (e.g., connected VANET), a vehicular ad hoc routing protocol (e.g., AODV and
geographic routing) may be required to support both unicast and OLSRv2) may be required to support both unicast and multicast in the
multicast in the links of the subnet with the same IPv6 prefix links of the subnet with the same IPv6 prefix. Instead of the
[VANET-Geo-Routing]. Instead of the vehicular ad hoc routing vehicular ad hoc routing protocol, Vehicular ND along with a prefix
protocol, Vehicular ND along with a prefix discovery option can be discovery option can be used to let vehicles exchange their prefixes
used to let vehicles exchange their prefixes in a multihop fashion in a multihop fashion [ID-Vehicular-ND]. With the exchanged
prefixes, they can compute their routing table (or IPv6 ND's neighbor
cache) for the multi-link subnet with a distance-vector algorithm
[Intro-to-Algorithms].
[ID-Vehicular-ND][ID-VND-Discovery]. With the exchanged prefixes, Also, an efficient, rapid DAD should be supported in a multi-link
they can compute their routing table (or IPv6 ND's neighbor cache) subnet to prevent or reduce IPv6 address conflicts in such a subnet
for the multi-link subnet with a distance-vector algorithm by using a multi-hop DAD optimization [ID-Vehicular-ND][RFC6775] or
[Intro-to-Algorithms]. Also, an efficient, rapid DAD should be
supported to prevent or reduce IPv6 address conflicts in the multi-
link subnet by using a DAD optimization [ID-Vehicular-ND][RFC6775] or
an IPv6 geographic-routing-based address autoconfiguration [GeoSAC]. an IPv6 geographic-routing-based address autoconfiguration [GeoSAC].
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 an efficient mobility management including location points requires an efficient mobility management including location
management and handover. Most of vehicles are equipped with a GPS management and handover. Most of vehicles are equipped with a GPS
receiver as part of a dedicated navigation system or a corresponding receiver as part of a dedicated navigation system or a corresponding
smartphone App. In the case where the provided location information smartphone App. The GPS receiver may not provide vehicles with
is precise enough, well-known temporary degradations in precision may accurate location information in adverse, local environments such as
occur due to system configuration or the adverse local environment. building area and tunnel. The location precision can be improved by
This precision is improved thanks to assistance by the RSUs or a the assistance from the RSUs or a cellular system with a navigation
cellular system with this navigation system. With this GPS system.
navigator, an efficient mobility management is possible by vehicles
periodically reporting their current position and trajectory (i.e., With this GPS navigator, an efficient mobility management is possible
navigation path) to RSUs and a Mobility Anchor (MA) in TCC. The RSUs by vehicles periodically reporting their current position and
and MA can predict the future positions of the vehicles with their trajectory (i.e., navigation path) to RSUs and a Mobility Anchor (MA)
mobility information (i.e., the current position, speed, direction, in TCC. The RSUs and MA can predict the future positions of the
and trajectory) for the efficient mobility management (e.g., vehicles with their mobility information (i.e., the current position,
proactive handover). For a better proactive handover, link-layer speed, direction, and trajectory) for the efficient mobility
parameters, such as the signal strength of a link-layer frame (e.g., management (e.g., proactive handover). For a better proactive
Received Channel Power Indicator (RCPI) [VIP-WAVE]), can be used to handover, link-layer parameters, such as the signal strength of a
determine the moment of a handover between RSUs along with mobility link-layer frame (e.g., Received Channel Power Indicator (RCPI)
information [ID-Vehicular-ND]. [VIP-WAVE]), can be used to determine the moment of a handover
between RSUs along with mobility information [ID-Vehicular-ND].
With the prediction of the vehicle mobility, MA can support RSUs to With the prediction of the vehicle mobility, MA can support RSUs to
perform DAD, data packet routing, horizontal handover (i.e., handover perform DAD, data packet routing, horizontal handover (i.e., handover
in wireless links using a homogeneous radio technology), and vertical in wireless links using a homogeneous radio technology), and vertical
handover (i.e., handover in wireless links using heterogeneous radio handover (i.e., handover in wireless links using heterogeneous radio
technologies) in a proactive manner. Even though a vehicle moves technologies) in a proactive manner. Even though a vehicle moves
into the wireless link under another RSU belonging to a different into the wireless link under another RSU belonging to a different
subnet, the RSU can proactively perform the DAD for the sake of the subnet, the RSU can proactively perform the DAD for the sake of the
vehicle, reducing IPv6 control traffic overhead in the wireless link vehicle, reducing IPv6 control traffic overhead in the wireless link
[ID-Vehicular-ND]. [ID-Vehicular-ND]. To prevent a hacker from impersonating RSUs as
bogus RSUs, RSUs and MA should have secure channels via IPsec.
Therefore, with a proactive handover and a multihop DAD in vehicular Therefore, with a proactive handover and a multihop DAD in vehicular
networks [ID-Vehicular-ND], RSUs can efficiently forward data packets networks [ID-Vehicular-ND], RSUs can efficiently forward data packets
from the wired network (or the wireless network) to a moving from the wired network (or the wireless network) to a moving
destination vehicle along its trajectory along with the MA. Thus, a destination vehicle along its trajectory along with the MA. Thus, a
moving vehicle can communicate with its corresponding vehicle in the moving vehicle can communicate with its corresponding vehicle in the
vehicular network or a host/server in the Internet along its vehicular network or a host/server in the Internet along its
trajectory. trajectory.
5.3. Security and Privacy 5.3. Security and Privacy
skipping to change at page 21, line 43 skipping to change at page 25, line 43
Available: Available:
http://www.path.berkeley.edu/research/automated-and- http://www.path.berkeley.edu/research/automated-and-
connected-vehicles/cooperative-adaptive-cruise-control, connected-vehicles/cooperative-adaptive-cruise-control,
2017. 2017.
[CASD] Shen, Y., Jeong, J., Oh, T., and S. Son, "CASD: A [CASD] Shen, Y., Jeong, J., Oh, T., and S. Son, "CASD: A
Framework of Context-Awareness Safety Driving in Vehicular Framework of Context-Awareness Safety Driving in Vehicular
Networks", International Workshop on Device Centric Cloud Networks", International Workshop on Device Centric Cloud
(DC2), March 2016. (DC2), March 2016.
[Cluster-Based-Routing]
Abboud, K. and W. Zhuang, "Impact of Microscopic Vehicle
Mobility on Cluster-Based Routing Overhead in VANETs",
IEEE Transactions on Vehicular Technology, Vol. 64, No.
12, December 2015.
[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.
[ETSI-GeoNetwork-IP] [ETSI-GeoNetwork-IP]
ETSI Technical Committee Intelligent Transport Systems, ETSI Technical Committee Intelligent Transport Systems,
"Intelligent Transport Systems (ITS); Vehicular "Intelligent Transport Systems (ITS); Vehicular
skipping to change at page 23, line 10 skipping to change at page 27, line 16
Scalable Address Autoconfiguration for VANET Using Scalable Address Autoconfiguration for VANET Using
Geographic Networking Concepts", IEEE International Geographic Networking Concepts", IEEE International
Symposium on Personal, Indoor and Mobile Radio Symposium on Personal, Indoor and Mobile Radio
Communications, September 2008. Communications, September 2008.
[H-DMM] Nguyen, T. and C. Bonnet, "A Hybrid Centralized- [H-DMM] Nguyen, T. and C. Bonnet, "A Hybrid Centralized-
Distributed Mobility Management for Supporting Highly Distributed Mobility Management for Supporting Highly
Mobile Users", IEEE International Conference on Mobile Users", IEEE International Conference on
Communications, June 2015. Communications, June 2015.
[H-NEMO] Nguyen, T. and C. Bonnet, "A Hybrid Centralized-
Distributed Mobility Management Architecture for Network
Mobility", IEEE International Symposium on A World of
Wireless, Mobile and Multimedia Networks, June 2015.
[ID-DNSNA] [ID-DNSNA]
Jeong, J., Ed., Lee, S., and J. Park, "DNS Name Jeong, J., Ed., Lee, S., and J. Park, "DNS Name
Autoconfiguration for Internet of Things Devices", draft- Autoconfiguration for Internet of Things Devices", draft-
jeong-ipwave-iot-dns-autoconf-04 (work in progress), jeong-ipwave-iot-dns-autoconf-04 (work in progress),
October 2018. October 2018.
[ID-Vehicular-ND] [ID-Vehicular-ND]
Xiang, Zhong., Jeong, J., Ed., and Y. Shen, "IPv6 Neighbor Jeong, J., Ed., Shen, Y., and Z. Xiang, "IPv6 Neighbor
Discovery for IP-Based Vehicular Networks", draft-xiang- Discovery for IP-Based Vehicular Networks", draft-jeong-
ipwave-vehicular-neighbor-discovery-00 (work in progress), ipwave-vehicular-neighbor-discovery-06 (work in progress),
November 2018. March 2019.
[ID-VND-Discovery]
Jeong, J., Ed., Shen, Y., Jo, Y., Jeong, J., and J. Lee,
"IPv6 Neighbor Discovery for Prefix and Service Discovery
in Vehicular Networks", draft-jeong-ipwave-vehicular-
neighbor-discovery-04 (work in progress), October 2018.
[Identity-Management] [Identity-Management]
Wetterwald, M., Hrizi, F., and P. Cataldi, "Cross-layer Wetterwald, M., Hrizi, F., and P. Cataldi, "Cross-layer
Identities Management in ITS Stations", The 10th Identities Management in ITS Stations", The 10th
International Conference on ITS Telecommunications, International Conference on ITS Telecommunications,
November 2010. November 2010.
[IEEE-802.11-OCB] [IEEE-802.11-OCB]
IEEE 802.11 Working Group, "Part 11: Wireless LAN Medium "Part 11: Wireless LAN Medium Access Control (MAC) and
Access Control (MAC) and Physical Layer (PHY) Physical Layer (PHY) Specifications", IEEE Std
Specifications", IEEE Std 802.11-2016, December 2016. 802.11-2016, December 2016.
[IEEE-802.11p] [IEEE-802.11p]
IEEE 802.11 Working Group, "Part 11: Wireless LAN Medium "Part 11: Wireless LAN Medium Access Control (MAC) and
Access Control (MAC) and Physical Layer (PHY) Physical Layer (PHY) Specifications - Amendment 6:
Specifications - Amendment 6: Wireless Access in Vehicular Wireless Access in Vehicular Environments", IEEE Std
Environments", IEEE Std 802.11p-2010, June 2010. 802.11p-2010, June 2010.
[Intro-to-Algorithms] [Intro-to-Algorithms]
H. Cormen, T., E. Leiserson, C., L. Rivest, R., and C. H. Cormen, T., E. Leiserson, C., L. Rivest, R., and C.
Stein, "Introduction to Algorithms, 3rd ed.", The Stein, "Introduction to Algorithms, 3rd ed.", The
MIT Press, July 2009. MIT Press, July 2009.
[IP-Passing-Protocol] [IP-Passing-Protocol]
Chen, Y., Hsu, C., and W. Yi, "An IP Passing Protocol for Chen, Y., Hsu, C., and W. Yi, "An IP Passing Protocol for
Vehicular Ad Hoc Networks with Network Fragmentation", Vehicular Ad Hoc Networks with Network Fragmentation",
Elsevier Computers & Mathematics with Applications, Elsevier Computers & Mathematics with Applications,
January 2012. January 2012.
[IPv6-over-802.11-OCB] [IPv6-over-802.11-OCB]
Petrescu, A., Benamar, N., Haerri, J., Lee, J., and T. Petrescu, A., Benamar, N., Haerri, J., Lee, J., and T.
Ernst, "Transmission of IPv6 Packets over IEEE 802.11 Ernst, "Transmission of IPv6 Packets over IEEE 802.11
Networks operating in mode Outside the Context of a Basic Networks operating in mode Outside the Context of a Basic
Service Set (IPv6-over-80211-OCB)", draft-ietf-ipwave- Service Set (IPv6-over-80211-OCB)", draft-ietf-ipwave-
ipv6-over-80211ocb-30 (work in progress), September 2018. ipv6-over-80211ocb-34 (work in progress), December 2018.
[IPv6-WAVE] [IPv6-WAVE]
Baccelli, E., Clausen, T., and R. Wakikawa, "IPv6 Baccelli, E., Clausen, T., and R. Wakikawa, "IPv6
Operation for WAVE - Wireless Access in Vehicular Operation for WAVE - Wireless Access in Vehicular
Environments", IEEE Vehicular Networking Conference, Environments", IEEE Vehicular Networking Conference,
December 2010. December 2010.
[ISO-ITS-IPv6] [ISO-ITS-IPv6]
ISO/TC 204, "Intelligent Transport Systems - ISO/TC 204, "Intelligent Transport Systems -
Communications Access for Land Mobiles (CALM) - IPv6 Communications Access for Land Mobiles (CALM) - IPv6
skipping to change at page 25, line 23 skipping to change at page 29, line 30
Protocol for Vehicular Ad Hoc Networks", Protocol for Vehicular Ad Hoc Networks",
Wiley International Journal of Communication Systems, Wiley International Journal of Communication Systems,
November 2014. November 2014.
[PMIP-NEMO-Analysis] [PMIP-NEMO-Analysis]
Lee, J., Ernst, T., and N. Chilamkurti, "Performance Lee, J., Ernst, T., and N. Chilamkurti, "Performance
Analysis of PMIPv6-Based Network Mobility for Intelligent Analysis of PMIPv6-Based Network Mobility for Intelligent
Transportation Systems", IEEE Transactions on Vehicular Transportation Systems", IEEE Transactions on Vehicular
Technology, January 2012. Technology, January 2012.
[RFC3561] Perkins, C., Belding-Royer, E., and S. Das, "Ad hoc On-
Demand Distance Vector (AODV) Routing", RFC 3561, July
2003.
[RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker,
"Randomness Requirements for Security", RFC 4086, June "Randomness Requirements for Security", RFC 4086, June
2005. 2005.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP Version 6 (IPv6)", RFC 4861, "Neighbor Discovery for IP Version 6 (IPv6)", RFC 4861,
September 2007. September 2007.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, September 2007. Address Autoconfiguration", RFC 4862, September 2007.
[RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in Extensions for Stateless Address Autoconfiguration in
IPv6", RFC 4941, September 2007. IPv6", RFC 4941, September 2007.
[RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V., [RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V.,
Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", Chowdhury, K., and B. Patil, "Proxy Mobile IPv6",
RFC 5213, August 2008. RFC 5213, August 2008.
[RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
Mobile IPv6", RFC 5844, May 2010.
[RFC5889] Baccelli, E. and M. Townsley, "IP Addressing Model in Ad [RFC5889] Baccelli, E. and M. Townsley, "IP Addressing Model in Ad
Hoc Networks", RFC 5889, September 2010. Hoc Networks", RFC 5889, September 2010.
[RFC5944] Perkins, C., Ed., "IP Mobility Support in IPv4, Revised", [RFC5944] Perkins, C., Ed., "IP Mobility Support in IPv4, Revised",
RFC 5944, November 2010. RFC 5944, November 2010.
[RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
Support in IPv6", RFC 6275, July 2011. Support in IPv6", RFC 6275, July 2011.
[RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762, [RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
February 2013. February 2013.
[RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service [RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", RFC 6763, February 2013. Discovery", RFC 6763, February 2013.
[RFC6775] Shelby, Z., Chakrabarti, S., Nordmark, E., and C. Bormann, [RFC6775] Shelby, Z., Chakrabarti, S., Nordmark, E., and C. Bormann,
"Neighbor Discovery Optimization for IPv6 over Low-Power "Neighbor Discovery Optimization for IPv6 over Low-Power
Wireless Personal Area Networks (6LoWPANs)", RFC 6775, Wireless Personal Area Networks (6LoWPANs)", RFC 6775,
November 2012. November 2012.
[RFC7181] Clausen, T., Dearlove, C., Jacquet, P., and U. Herberg,
"The Optimized Link State Routing Protocol Version 2",
RFC 7181, April 2014.
[RFC7333] Chan, H., Liu, D., Seite, P., Yokota, H., and J. Korhonen, [RFC7333] Chan, H., Liu, D., Seite, P., Yokota, H., and J. Korhonen,
"Requirements for Distributed Mobility Management", "Requirements for Distributed Mobility Management",
RFC 7333, August 2014. RFC 7333, August 2014.
[RFC7429] Liu, D., Zuniga, JC., Seite, P., Chan, H., and CJ. [RFC7429] Liu, D., Zuniga, JC., Seite, P., Chan, H., and CJ.
Bernardos, "Distributed Mobility Management: Current Bernardos, "Distributed Mobility Management: Current
Practices and Gap Analysis", RFC 7429, January 2015. Practices and Gap Analysis", RFC 7429, January 2015.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 8200, July 2017. (IPv6) Specification", RFC 8200, July 2017.
skipping to change at page 30, line 9 skipping to change at page 34, line 9
functions based on IPv6 use multicast for control-plane messages, functions based on IPv6 use multicast for control-plane messages,
such as Neighbor Discovery (ND) and Service Discovery, such as Neighbor Discovery (ND) and Service Discovery,
[Multicast-802] describes that the ND process may fail due to [Multicast-802] describes that the ND process may fail due to
unreliable wireless link, causing failure of the DAD process. Also, unreliable wireless link, causing failure of the DAD process. Also,
the Router Advertisement messages can be lost in multicasting. the Router Advertisement messages can be lost in multicasting.
A.4. DNS Naming Services and Service Discovery A.4. DNS Naming Services and Service Discovery
When two vehicular nodes communicate with each other using the DNS When two vehicular nodes communicate with each other using the DNS
name of the partner node, DNS naming service (i.e., DNS name name of the partner node, DNS naming service (i.e., DNS name
resolution) is required. As shown in Figure 2 and Figure 3, a resolution) is required. As shown in Figure 2 and Figure 3, a DNS
recursive DNS server (RDNSS) within an internal network can perform server within an internal network can perform such DNS name
such DNS name resolution for the sake of other vehicular nodes. resolution for the sake of other vehicular nodes.
A service discovery service is required for an application in a A service discovery service is required for an application in a
vehicular node to search for another application or server in another vehicular node to search for another application or server in another
vehicular node, which resides in either the same internal network or vehicular node, which resides in either the same internal network or
the other internal network. In V2I or V2V networking, as shown in the other internal network. In V2I or V2V networking, as shown in
Figure 2 and Figure 3, such a service discovery service can be Figure 2 and Figure 3, such a service discovery service can be
provided by either DNS-based Service Discovery (DNS-SD) [RFC6763] provided by either DNS-based Service Discovery (DNS-SD) [RFC6763]
with mDNS [RFC6762] or the vehicular ND with a new option for service with mDNS [RFC6762] or the vehicular ND with a new option for service
discovery [ID-Vehicular-ND][ID-VND-Discovery]. discovery [ID-Vehicular-ND].
A.5. IPv6 over Cellular Networks A.5. IPv6 over Cellular Networks
Recently, 3GPP has announced a set of new technical specifications, Recently, 3GPP has announced a set of new technical specifications,
such as Release 14 (3GPP-R14), which proposes an architecture such as Release 14 (3GPP-R14) [TS-23.285-3GPP], which proposes an
enhancements for V2X services using the modified sidelink interface architecture enhancements for V2X services using the modified
that originally is designed for the LTE-D2D communications. 3GPP-R14 sidelink interface that originally is designed for the LTE-Device-to-
specifies that the V2X services only support IPv6 implementation. Device (D2D) communications. 3GPP-R14 specifies that the V2X
3GPP is also investigating and discussing the evolved V2X services in services only support IPv6 implementation. 3GPP is also
the next generation cellular networks, i.e., 5G new radio (5G-NR), investigating and discussing the evolved V2X services in the next
for advanced V2X communications and automated vehicles' applications. generation cellular networks, i.e., 5G new radio (5G-NR), for
advanced V2X communications and automated vehicles' applications.
A.5.1. Cellular V2X (C-V2X) Using 4G-LTE A.5.1. Cellular V2X (C-V2X) Using 4G-LTE
Before 3GPP-R14, some researchers have studied the potential usage of Before 3GPP-R14, some researchers have studied the potential usage of
C-V2X communications. For example, [VMaSC-LTE] explores a multihop C-V2X communications. For example, [VMaSC-LTE] explores a multihop
cluster-based hybrid architecture using both DSRC and LTE for safety cluster-based hybrid architecture using both DSRC and LTE for safety
message dissemination. Most of the research considers a short message dissemination. Most of the research considers a short
message service for safety instead of IP datagram forwarding. In message service for safety instead of IP datagram forwarding. In
other C-V2X research, the standard IPv6 is assumed. other C-V2X research, the standard IPv6 is assumed.
The 3GPP technical specification [TS-23.285-3GPP] states that both IP The 3GPP technical specification of [TS-23.285-3GPP] states that both
based and non-IP based V2X messages are supported, and only IPv6 is IP based and non-IP based V2X messages are supported, and only IPv6
supported for IP based messages. Moreover, [TS-23.285-3GPP] is supported for IP based messages. Moreover, [TS-23.285-3GPP]
instructs that a UE autoconfigures a link-local IPv6 address by instructs that a UE autoconfigures a link-local IPv6 address by
following [RFC4862], but without sending Neighbor Solicitation and following SLAAC in [RFC4862], but without sending Neighbor
Neighbor Advertisement messages for DAD. This is because a unique Solicitation and Neighbor Advertisement messages for DAD. This is
prefix is allocated to each node by the 3GPP network, so the IPv6 because a unique prefix is allocated to each node by the 3GPP
addresses cannot be duplicate. network, so the IPv6 addresses cannot be duplicate.
A.5.2. Cellular V2X (C-V2X) Using 5G A.5.2. Cellular V2X (C-V2X) Using 5G
The emerging services, functions, and applications, which are The emerging services, functions, and applications, which are
developped in automotive industry, demand reliable and efficient developped in automotive industry, demand reliable and efficient
communication infrastructure for road networks. Correspondingly, the communication infrastructure for road networks. Correspondingly,
support of enhanced V2X (eV2X)-based services by future converged and enhanced V2X (eV2X)-based services can be supported by 5G systems.
interoperable 5G systems is required. The 3GPP Technical Report The 3GPP Technical Report of [TR-22.886-3GPP] is studying new use
[TR-22.886-3GPP] is studying new use cases and the corresponding cases and the corresponding service requirements for V2X (including
service requirements for V2X (including V2V and V2I) using 5G in both V2V and V2I) using 5G in both infrastructure mode and the sidelink
infrastructure mode and the sidelink variations in the future. variations in the future.
Appendix B. Changes from draft-ietf-ipwave-vehicular-networking-06 Appendix B. Changes from draft-ietf-ipwave-vehicular-networking-07
The following changes are made from draft-ietf-ipwave-vehicular- The following changes are made from draft-ietf-ipwave-vehicular-
networking-06: networking-07:
o In Figure 1, a vehicular network architecture is modified to show o This version is revised based on the comments from Charlie Perkins
a vehicular link model in a multi-link subnet with vehicular and Sri Gundavelli.
wireless links.
o In Section 5.1, a Vehicular Neighbor Discovery (VND) o In Section 4.1, the existing protocols relevant to IP vehicular
[ID-Vehicular-ND] is introduced along with a vehicular link model networking are summarized and analyzed with pros and cons. This
in a multi-link subnet. In such a subnet, the description of MAC subsection addresses the requirements for IP vehicular networking.
Address Pseudonym, Prefix Dissemination/Exchange, and Routing is
clarified.
o In Section 5.2, a proactive handover is introduced for an o In Figure 1, a vehicular network architecture is modified to
efficient mobility management with the cooperation among vehicles, clarify a multi-link subnet consisting of vehicular wireless
RSUs, and MA along with link-layer parameters, such as Received links, and to provide efficient vehicular communications for V2I &
Channel Power Indicator (RCPI). V2V to vehicles whose wireless interface is configured with a
global IP address.
Appendix C. Acknowledgments Appendix C. Acknowledgments
This work was supported by Basic Science Research Program through the This work was supported by Basic Science Research Program through the
National Research Foundation of Korea (NRF) funded by the Ministry of National Research Foundation of Korea (NRF) funded by the Ministry of
Education (2017R1D1A1B03035885). Education (2017R1D1A1B03035885).
This work was supported in part by Global Research Laboratory Program This work was supported in part by Global Research Laboratory Program
through the NRF funded by the Ministry of Science and ICT (MSIT) through the NRF funded by the Ministry of Science and ICT (MSIT)
(NRF-2013K1A1A2A02078326) and by the DGIST R&D Program of the MSIT (NRF-2013K1A1A2A02078326) and by the DGIST R&D Program of the MSIT
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