draft-ietf-ipwave-vehicular-networking-11.txt   draft-ietf-ipwave-vehicular-networking-12.txt 
IPWAVE Working Group J. Jeong, Ed. IPWAVE Working Group J. Jeong, Ed.
Internet-Draft Sungkyunkwan University Internet-Draft Sungkyunkwan University
Intended status: Informational July 20, 2019 Intended status: Informational October 3, 2019
Expires: January 21, 2020 Expires: April 5, 2020
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-11 draft-ietf-ipwave-vehicular-networking-12
Abstract Abstract
This document discusses the problem statement and use cases of IP- This document discusses the problem statement and use cases of IP-
based vehicular networking for Intelligent Transportation Systems based vehicular networking for Intelligent Transportation Systems
(ITS). The main scenarios of vehicular communications are vehicle- (ITS). The main scenarios of vehicular communications are vehicle-
to-vehicle (V2V), vehicle-to-infrastructure (V2I), and vehicle-to- to-vehicle (V2V), vehicle-to-infrastructure (V2I), and vehicle-to-
everything (V2X) communications. First, this document explains use everything (V2X) communications. First, this document explains use
cases using V2V, V2I, and V2X networking. Next, it makes a problem cases using V2V, V2I, and V2X networking. Next, it makes a problem
statement about key aspects in IP-based vehicular networking, such as statement about key aspects in IP-based vehicular networking, such as
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 21, 2020. This Internet-Draft will expire on April 5, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 20 skipping to change at page 2, line 20
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. V2V . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1. V2V . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. V2I . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.2. V2I . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.3. V2X . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.3. V2X . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Vehicular Networks . . . . . . . . . . . . . . . . . . . . . 7 4. Vehicular Networks . . . . . . . . . . . . . . . . . . . . . 8
4.1. Vehicular Network Architecture . . . . . . . . . . . . . 8 4.1. Vehicular Network Architecture . . . . . . . . . . . . . 9
4.2. V2I-based Internetworking . . . . . . . . . . . . . . . . 9 4.2. V2I-based Internetworking . . . . . . . . . . . . . . . . 11
4.3. V2V-based Internetworking . . . . . . . . . . . . . . . . 11 4.3. V2V-based Internetworking . . . . . . . . . . . . . . . . 13
5. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 13 5. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 14
5.1. Neighbor Discovery . . . . . . . . . . . . . . . . . . . 13 5.1. Neighbor Discovery . . . . . . . . . . . . . . . . . . . 15
5.1.1. Link Model . . . . . . . . . . . . . . . . . . . . . 14 5.1.1. Link Model . . . . . . . . . . . . . . . . . . . . . 16
5.1.2. MAC Address Pseudonym . . . . . . . . . . . . . . . . 16 5.1.2. MAC Address Pseudonym . . . . . . . . . . . . . . . . 17
5.1.3. Prefix Dissemination/Exchange . . . . . . . . . . . . 16 5.1.3. Routing . . . . . . . . . . . . . . . . . . . . . . . 18
5.1.4. Routing . . . . . . . . . . . . . . . . . . . . . . . 17 5.2. Mobility Management . . . . . . . . . . . . . . . . . . . 19
5.2. Mobility Management . . . . . . . . . . . . . . . . . . . 17 6. Security Considerations . . . . . . . . . . . . . . . . . . . 20
5.3. Security and Privacy . . . . . . . . . . . . . . . . . . 18 7. Informative References . . . . . . . . . . . . . . . . . . . 21
6. Security Considerations . . . . . . . . . . . . . . . . . . . 19
7. Informative References . . . . . . . . . . . . . . . . . . . 19
Appendix A. Changes from draft-ietf-ipwave-vehicular- Appendix A. Changes from draft-ietf-ipwave-vehicular-
networking-10 . . . . . . . . . . . . . . . . . . . 25 networking-11 . . . . . . . . . . . . . . . . . . . 27
Appendix B. Acknowledgments . . . . . . . . . . . . . . . . . . 25 Appendix B. Acknowledgments . . . . . . . . . . . . . . . . . . 28
Appendix C. Contributors . . . . . . . . . . . . . . . . . . . . 25 Appendix C. Contributors . . . . . . . . . . . . . . . . . . . . 28
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 27 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 30
1. Introduction 1. Introduction
Vehicular networking studies have mainly focused on improving safety Vehicular networking studies have mainly focused on improving safety
and efficiency, and also enabling entertainment in vehicular and efficiency, and also enabling entertainment in vehicular
networks. The Federal Communications Commission (FCC) in the US networks. The Federal Communications Commission (FCC) in the US
allocated wireless channels for Dedicated Short-Range Communications allocated wireless channels for Dedicated Short-Range Communications
(DSRC) [DSRC] in the Intelligent Transportation Systems (ITS) with (DSRC) [DSRC] in the Intelligent Transportation Systems (ITS) with
the frequency band of 5.850 - 5.925 GHz (i.e., 5.9 GHz band). DSRC- the frequency band of 5.850 - 5.925 GHz (i.e., 5.9 GHz band). DSRC-
based wireless communications can support vehicle-to-vehicle (V2V), based wireless communications can support vehicle-to-vehicle (V2V),
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[WAVE-1609.3] defines related services at network and transport [WAVE-1609.3] defines related services at network and transport
layers, and IEEE 1609.4 [WAVE-1609.4] specifies the multi-channel layers, and IEEE 1609.4 [WAVE-1609.4] specifies the multi-channel
operation. IEEE 802.11p was first a separate amendment, but was operation. IEEE 802.11p was first a separate amendment, but was
later rolled into the base 802.11 standard (IEEE 802.11-2012) as IEEE later rolled into the base 802.11 standard (IEEE 802.11-2012) as IEEE
802.11 Outside the Context of a Basic Service Set (OCB) in 2012 802.11 Outside the Context of a Basic Service Set (OCB) in 2012
[IEEE-802.11-OCB]. [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], MIPv6 [RFC6275], and Proxy MIPv6 protocols (e.g., MIPv4 [RFC5944], MIPv6 [RFC6275], and Proxy MIPv6
(PMIPv6) [RFC5213][RFC5844]) can be applied to vehicular networks. (PMIPv6) [RFC5213][RFC5844]) can be applied to vehicular networks.
In Europe, ETSI has standardized a GeoNetworking (GN) protocol In addition, ISO has approved a standard specifying the IPv6 network
[ETSI-GeoNetworking] and a protocol adaptation sub-layer from
GeoNetworking to IPv6 [ETSI-GeoNetwork-IP]. GN protocols are useful
to route an event or notification message to vehicles around a
geographic position, such as an accident area in a roadway. In
addition, ISO has approved a standard specifying the IPv6 network
protocols and services to be used for Communications Access for Land protocols and services to be used for Communications Access for Land
Mobiles (CALM) [ISO-ITS-IPv6]. Mobiles (CALM) [ISO-ITS-IPv6].
This document describes use cases and a problem statement about IP- This document describes use cases and a problem statement about IP-
based vehicular networking for ITS, which is named IP Wireless Access based vehicular networking for ITS, which is named IP Wireless Access
in Vehicular Environments (IPWAVE). First, it introduces the use in Vehicular Environments (IPWAVE). First, it introduces the use
cases for using V2V, V2I, and V2X networking in ITS. Next, it makes cases for using V2V, V2I, and V2X networking in ITS. Next, it makes
a problem statement about key aspects in IPWAVE, namely, IPv6 a problem statement about key aspects in IPWAVE, namely, IPv6
Neighbor Discovery, Mobility Management, and Security & Privacy. For Neighbor Discovery, Mobility Management, and Security & Privacy. For
each key aspect of the problem statement, this document specifies each key aspect of the problem statement, this document specifies
requirements in IP-based vehicular networking, and proposes the requirements in IP-based vehicular networking, and proposes the
direction of solutions fulfilling those requirements. This document direction of solutions fulfilling those requirements. This document
is intended to motivate development of key protocols for IPWAVE. is intended to motivate development of key protocols for IPWAVE.
2. Terminology 2. Terminology
This document uses the following definitions: This document uses the following definitions:
o Class-Based Safety Plan: A vehicle can make safety plan by
classifying the surrounding vehicles into different groups for
safety purposes according to the geometrical relationship among
them. The vehicle groups can be classified as Line-of-Sight
Unsafe, Non-Line-of-Sight Unsafe, and Safe groups [CASD].
o Context-Awareness: A vehicle can be aware of spatial-temporal
mobility information (e.g., position, speed, direction, and
acceleration/deceleration) of surrounding vehicles for both safety
and non-safety uses through sensing or communication [CASD].
o LiDAR: "Light Detection and Ranging". It is a scanning device to o LiDAR: "Light Detection and Ranging". It is a scanning device to
measure a distance to an object by emitting pulsed laser light and measure a distance to an object by emitting pulsed laser light and
measuring the reflected pulsed light. measuring the reflected pulsed light.
o Mobility Anchor (MA): A node that maintains IP addresses and o Mobility Anchor (MA): A node that maintains IP addresses and
mobility information of vehicles in a road network to support mobility information of vehicles in a road network to support
their address autoconfiguration and mobility management with a their address autoconfiguration and mobility management with a
binding table. An MA has end-to-end connections with RSUs under binding table. An MA has end-to-end connections with RSUs under
its control. its control.
o On-Board Unit (OBU): A node that has physical communication o On-Board Unit (OBU): A node that has physical communication
devices (e.g., IEEE 802.11-OCB and Cellular V2X (C-V2X) devices (e.g., IEEE 802.11-OCB and Cellular V2X (C-V2X)
[TS-23.285-3GPP]) for wireless communications with other OBUs and [TS-23.285-3GPP]) for wireless communications with other OBUs and
RSUs, and may be connected to in-vehicle devices or networks. An RSUs, and may be connected to in-vehicle devices or networks. An
OBU is mounted on a vehicle. OBU is mounted on a vehicle.
o OCB: "Outside the Context of a Basic Service Set" o OCB: "Outside the Context of a Basic Service Set". It is
[IEEE-802.11-OCB]. differentiated from the Basic Service Set (BSS) mode in IEEE
802.11 standard. A node in OCB mode can directly transmit packets
to other nodes in its wireless range without the authentication or
association process defined in BSS mode [IEEE-802.11-OCB].
o Platooning: Moving vehicles can be grouped together to reduce air-
resistance for energy efficiency and reduce the number of drivers
such that only the leading vehicle has a driver and the other
vehicles are autonomous vehicles without a driver and closely
following the leading vehicle [Truck-Platooning].
o Road-Side Unit (RSU): A node that has physical communication o Road-Side Unit (RSU): A node that has physical communication
devices (e.g., IEEE 802.11-OCB and C-V2X) for wireless devices (e.g., IEEE 802.11-OCB and C-V2X) for wireless
communications with vehicles and is also connected to the Internet communications with vehicles and is also connected to the Internet
as a router or switch for packet forwarding. An RSU is typically through a router or switch for packet forwarding. An RSU can
deployed on the road infrastructure, either at an intersection or accommodate multiple routers (or switches) and servers (e.g., DNS
in a road segment, but may also be located in a car parking area. server and edge computing server) in its internal network as an
edge computing system. An RSU is typically deployed on the road
infrastructure, either at an intersection or in a road segment,
but may also be located in a 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 Vehicle: A Vehicle in this document is a node that has an OBU for o Vehicle: A Vehicle in this document is a node that has an OBU for
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o Platooning in a highway; o Platooning in a highway;
o Cooperative environment sensing. o Cooperative environment sensing.
These four techniques will be important elements for self-driving These four techniques will be important elements for self-driving
vehicles. vehicles.
Context-Aware Safety Driving (CASD) navigator [CASD] can help drivers Context-Aware Safety Driving (CASD) navigator [CASD] can help drivers
to drive safely by alerting the drivers about dangerous obstacles and to drive safely by alerting the drivers about dangerous obstacles and
situations. That is, CASD navigator displays obstables or situations. That is, CASD navigator displays obstacles or
neighboring vehicles relevant to possible collisions in real-time neighboring vehicles relevant to possible collisions in real-time
through V2V networking. CASD provides vehicles with a class-based through V2V networking. CASD provides vehicles with a class-based
automatic safety action plan, which considers three situations, automatic safety action plan, which considers three situations,
namely, the Line-of-Sight unsafe, Non-Line-of-Sight unsafe, and safe namely, the Line-of-Sight unsafe, Non-Line-of-Sight unsafe, and safe
situations. This action plan can be put into action among multiple situations. This action plan can be put into action among multiple
vehicles using V2V networking. vehicles using V2V networking.
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
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A pedestrian protection service, such as Safety-Aware Navigation A pedestrian protection service, such as Safety-Aware Navigation
Application (SANA) [SANA], using V2I2P networking can reduce the Application (SANA) [SANA], using V2I2P networking can reduce the
collision of a vehicle and a pedestrian carrying a smartphone collision of a vehicle and a pedestrian carrying a smartphone
equipped with a network device for wireless communication (e.g., equipped with a network device for wireless communication (e.g.,
WiFi) with an RSU. Vehicles and pedestrians can also communicate WiFi) with an RSU. Vehicles and pedestrians can also communicate
with each other via an RSU that delivers scheduling information for with each other via an RSU that delivers scheduling information for
wireless communication in order to save the smartphones' battery wireless communication in order to save the smartphones' battery
through sleeping mode. through sleeping mode.
For Vehicle-to-Pedestrian (V2P), a vehicle and a pedestrian's For Vehicle-to-Pedestrian (V2P), a vehicle can directly communicate
smartphone can directly communicate with each other via V2X without with a pedestrian's smartphone by V2X without RSU relaying. Light-
the relaying of an RSU as in the V2V scenario that the pedestrian's weight mobile nodes such as bicycles may also communicate directly
smartphone is regarded as a vehicle with a wireless media interface with a vehicle for collision avoidance using V2V.
to be able to communicate with another vehicle. There are light-
weight mobile nodes such as bicycle and motorcycle, and they can
communicate directly with a vehicle for collision avoidance using
V2V.
4. Vehicular Networks 4. Vehicular Networks
This section describes a vehicular network architecture supporting This section describes a vehicular network architecture supporting
V2V, V2I, and V2X communications in vehicular networks. Also, it V2V, V2I, and V2X communications in vehicular networks. Also, it
describes an internal network within a vehicle or RSU, and the describes an internal network within a vehicle or RSU, and the
internetworking between the internal networks via DSRC links. internetworking between the internal networks via DSRC links.
Traffic Control Center in Vehicular Cloud Traffic Control Center in Vehicular Cloud
*-----------------------------------------* *******************************************
* * * *
* +-----------------+ * * +-----------------+ *
* | Mobility Anchor | * * | Mobility Anchor | *
* +-----------------+ * * +-----------------+ *
* ^ * * ^ *
* | * * | Ethernet *
*--------------------v--------------------* * v *
^ ^ ^ *******************************************
| | | ^ ^ ^
| | | | Ethernet | Ethernet | Ethernet
v v v | | |
+--------+ Ethernet +--------+ +--------+ v v v
+--------+ Ethernet +--------+ Ethernet +--------+
| RSU1 |<-------->| RSU2 |<---------->| RSU3 | | RSU1 |<-------->| RSU2 |<---------->| RSU3 |
+--------+ +--------+ +--------+ +--------+ +--------+ +--------+
^ ^ ^ ^ ^ ^
: : : : : :
+-----------------+ +-----------------+ +-----------------+ +-----------------+ +-----------------+ +-----------------+
| : V2I | | V2I : | | V2I : | | : V2I | | : V2I | | : V2I |
| v | | v | | v | | v | | v | | v |
+--------+ | +--------+ | | +--------+ | | +--------+ | +--------+ | +--------+ | | +--------+ | | +--------+ |
|Vehicle1|===> |Vehicle2|===>| | |Vehicle3|===>| | |Vehicle4|===>| |Vehicle1|===> |Vehicle2|===>| | |Vehicle3|===>| | |Vehicle4|===>|
| |<...>| |<........>| | | | | | | +--------+<...>+--------+<........>+--------+ | | +--------+ |
+--------+ V2V +--------+ V2V +--------+ | | +--------+ | V2V ^ V2V ^ | | ^ |
| | | | | | | : V2V | | : V2V | | : V2V |
| v | | v | | v |
| +--------+ | | +--------+ | | +--------+ |
| |Vehicle5|===> | | |Vehicle6|===>| | |Vehicle7|==>|
| +--------+ | | +--------+ | | +--------+ |
+-----------------+ +-----------------+ +-----------------+ +-----------------+ +-----------------+ +-----------------+
Subnet1 Subnet2 Subnet3 Subnet1 Subnet2 Subnet3
(Prefix1) (Prefix2) (Prefix3)
<----> 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
4.1. Vehicular Network Architecture 4.1. Vehicular Network Architecture
Figure 1 shows an architecture for V2I and V2V networking in a road Figure 1 shows an architecture for V2I and V2V networking in a road
network. As shown in this figure, RSUs as routers and vehicles with network. The vehicular network architecture contains vehicles, RSUs,
OBU have wireless media interfaces for VANET. Furthermore, the Vehicular Cloud, Traffic Control Center, and Mobility Anchor as
wireless media interfaces are autoconfigured with a global IPv6 components. However, some components in the vehicular network
prefix (e.g., 2001:DB8:1:1::/64) to support both V2V and V2I architecture may not be needed for vehicular networking, such as
networking. Note that 2001:DB8::/32 is a documentation prefix Vehicular Cloud, Traffic Control Center, and Mobility Anchor.
[RFC3849] for example prefixes in this document, and also that any
routable IPv6 address needs to be routable in a VANET and a vehicular As shown in this figure, RSUs as routers and vehicles with OBU have
network including RSUs. wireless media interfaces for VANET. Furthermore, the wireless media
interfaces are autoconfigured with a global IPv6 prefix (e.g.,
2001:DB8:1:1::/64) to support both V2V and V2I networking. Note that
2001:DB8::/32 is a documentation prefix [RFC3849] for example
prefixes in this document, and also that any routable IPv6 address
needs to be routable in a VANET and a vehicular network including
RSUs.
For IPv6 packets transported over IEEE 802.11-OCB, For IPv6 packets transported over IEEE 802.11-OCB,
[IPv6-over-802.11-OCB] specifies several details, including Maximum [IPv6-over-802.11-OCB] specifies several details, including Maximum
Transmission Unit (MTU), frame format, link-local address, address Transmission Unit (MTU), frame format, link-local address, address
mapping for unicast and multicast, stateless autoconfiguration, and mapping for unicast and multicast, stateless autoconfiguration, and
subnet structure. An Ethernet Adaptation (EA) layer is in charge of subnet structure. An Ethernet Adaptation (EA) layer is in charge of
transforming some parameters between IEEE 802.11 MAC layer and IPv6 transforming some parameters between IEEE 802.11 MAC layer and IPv6
network layer, which is located between IEEE 802.11-OCB's logical network layer, which is located between IEEE 802.11-OCB's logical
link control layer and IPv6 network layer. This IPv6 over 802.11-OCB link control layer and IPv6 network layer. This IPv6 over 802.11-OCB
can be used for both V2V and V2I in IP-based vehicular networks. can be used for both V2V and V2I in IP-based vehicular networks.
In Figure 1, three RSUs (RSU1, RSU2, and RSU3) are deployed in the In Figure 1, three RSUs (RSU1, RSU2, and RSU3) are deployed in the
road network and are connected to a Vehicular Cloud through the road network and are connected to a Vehicular Cloud through the
Internet. A Traffic Control Center (TCC) is connected to the Internet. A Traffic Control Center (TCC) is connected to the
Vehicular Cloud for the management of RSUs and vehicles in the road Vehicular Cloud for the management of RSUs and vehicles in the road
network. A Mobility Anchor (MA) is located in the TCC as its key network. A Mobility Anchor (MA) can be located in the TCC as its key
component for the mobility management of vehicles. Two vehicles component for the mobility management of vehicles. Vehicle2,
(Vehicle1 and Vehicle2) are wirelessly connected to RSU1, and one Vehicle3, and Vehicle4 are wirelessly connected to RSU1, RSU2, and
vehicle (Vehicle3) is wirelessly connected to RSU2. The wireless RSU3, respectively. The three wireless networks of RSU1, RSU2, and
networks of RSU1 and RSU2 belong to two different subnets (Subnet1 RSU3 can belong to three different subnets (i.e., Subnet1, Subnet2,
and Subnet2), respectively. Another vehicle (Vehicle4) belonging to and Subnet3), respectively. Those three subnets use three different
another subnet (Subnet3) is wirelessly connected to RSU3. prefixes (i.e., Prefix1, Prefix2, and Prefix3).
A single subnet prefix can span multiple vehicles in VANET. For
example, in Figure 1, for Prefix 1, three vehicles (i.e., Vehicle1,
Vehicle2, and Vehicle5) can construct a connected VANET. Also, for
Prefix 2, two vehicles (i.e., Vehicle3 and Vehicle6) can construct
another connected VANET, and for Prefix 3, two vehicles (i.e.,
Vehicle4 and Vehicle7) can construct another connected VANET.
In wireless subnets in vehicular networks (e.g., Subnet1 and Subnet2 In wireless subnets in vehicular networks (e.g., Subnet1 and Subnet2
in Figure 1), vehicles can construct a connected VANET (with an in Figure 1), vehicles can construct a connected VANET (with an
arbitrary graph topology) and can communicate with each other via V2V arbitrary graph topology) and can communicate with each other via V2V
communication. Vehicle1 can communicate with Vehicle2 via V2V communication. Vehicle1 can communicate with Vehicle2 via V2V
communication, and Vehicle2 can communicate with Vehicle3 via V2V communication, and Vehicle2 can communicate with Vehicle3 via V2V
communication because they are within the wireless communication communication because they are within the wireless communication
range for each other. On the other hand, Vehicle3 can communicate range for each other. On the other hand, Vehicle3 can communicate
with Vehicle4 via the vehicular infrastructure (i.e., RSU2 and RSU3) with Vehicle4 via the vehicular infrastructure (i.e., RSU2 and RSU3)
by employing V2I (i.e., V2I2V) communication because they are not by employing V2I (i.e., V2I2V) communication because they are not
skipping to change at page 9, line 46 skipping to change at page 11, line 5
control plane can be separated from the data plane for efficient control plane can be separated from the data plane for efficient
mobility management and data forwarding. The mobility information of mobility management and data forwarding. The mobility information of
a GPS receiver mounted in its vehicle (e.g., position, speed, and a GPS receiver mounted in its vehicle (e.g., position, speed, and
direction) can be used to accommodate mobility-aware proactive direction) can be used to accommodate mobility-aware proactive
protocols. Vehicles can use the TCC as their Home Network having a protocols. Vehicles can use the TCC as their Home Network having a
home agent for mobility management as in MIPv6 [RFC6275] and PMIPv6 home agent for mobility management as in MIPv6 [RFC6275] and PMIPv6
[RFC5213], so the TCC maintains the mobility information of vehicles [RFC5213], so the TCC maintains the mobility information of vehicles
for location management. IP tunneling over the wireless link should for location management. IP tunneling over the wireless link should
be avoided for performance efficiency. be avoided for performance efficiency.
4.2. V2I-based Internetworking
This section discusses the internetworking between a vehicle's
internal network (i.e., moving network) and an RSU's internal network
(i.e., fixed network) via V2I communication.
+-----------------+ +-----------------+
(*)<........>(*) +----->| Vehicular Cloud | (*)<........>(*) +----->| Vehicular Cloud |
2001:DB8:1:1::/64 | | | +-----------------+ 2001:DB8:1:1::/64 | | | +-----------------+
+------------------------------+ +---------------------------------+ +------------------------------+ +---------------------------------+
| v | | v v | | v | | v v |
| +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ |
| | Host1 | | DNS1 | |Router1| | | |Router3| | DNS2 | | Host3 | | | | Host1 | | DNS1 | |Router1| | | |Router3| | DNS2 | | Host3 | |
| +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ |
| ^ ^ ^ | | ^ ^ ^ | | ^ ^ ^ | | ^ ^ ^ |
| | | | | | | | | | | | | | | | | | | |
skipping to change at page 10, line 35 skipping to change at page 11, line 35
| 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
Nowadays, a vehicle's internal network tends to be Ethernet to 4.2. V2I-based Internetworking
interconnect electronic control units in a vehicle. It can also
support WiFi and Bluetooth to accommodate a driver's and passenger's This section discusses the internetworking between a vehicle's
mobile devices (e.g., smartphone and tablet). In this trend, it is internal network (i.e., moving network) and an RSU's internal network
reasonable to consider a vehicle's internal network (i.e., moving (i.e., fixed network) via V2I communication. Note that an RSU can
network) and also the interaction between the internal network and an accommodate multiple routers (or switches) and servers (e.g., DNS
external network within another vehicle or RSU. A vehicle's internal server and edge computing server) in its internal network as an edge
network often uses Ethernet to interconnect control units in the computing system.
vehicle. The internal network also supports WiFi and Bluetooth to
accommodate a driver's and passenger's mobile devices (e.g., A vehicle's internal network often uses Ethernet to interconnect
smartphone or tablet). It is reasonable to consider the interaction control units in the vehicle. The internal network also supports
between the internal network and an external network within another WiFi and Bluetooth to accommodate a driver's and passenger's mobile
vehicle or RSU. devices (e.g., smartphone or tablet). It is reasonable to consider
the interaction between the internal network and an external network
within another vehicle or RSU.
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. Internetworking between two internal networks via V2I RSU. Internetworking between two internal networks via V2I
communication requires an exchange of network prefix and other 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-Vehicular-ND]. For ND-based prefix discovery, prefix discovery [ID-Vehicular-ND]. For ND-based prefix discovery,
network prefixes and parameters should be registered with a vehicle's network prefixes and parameters should be registered with a vehicle's
router and an RSU router with an external network interface in router and an RSU router with an external network interface in
skipping to change at page 11, line 26 skipping to change at page 12, line 28
address of an external network interface for the internetworking with address of an external network interface for the internetworking with
another vehicle or RSU. The IP layer information includes the IP another vehicle or RSU. The IP layer information includes the IP
address and prefix of an external network interface for the address and prefix of an external network interface for the
internetworking with another vehicle or RSU. 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. A DNS service should be moving network and the RSU's fixed network. A DNS service should be
supported for the DNS name resolution of in-vehicle devices within a supported for the DNS name resolution of in-vehicle devices within a
vehicle's internal network as well as for the DNS name resolution of vehicle's internal network as well as for the DNS name resolution of
those devices from a remote host in the Internet for on-line those devices from a remote host in the Internet (e.g., a customer's
diagnosis (e.g., an automotive service center server). The DNS names web browser and an automotive service center system). The DNS names
of in-vehicle devices and their service names can be registered with of in-vehicle devices and their service names can be registered with
a DNS server in a vehicle or an RSU, as shown in Figure 2. a DNS server in a vehicle or an RSU, as shown in Figure 2.
Figure 2 also shows internetworking between the vehicle's moving Figure 2 also 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 network (Moving Network1) inside Vehicle1. Vehicle1 has the DNS
Server (DNS1), the two hosts (Host1 and Host2), and the two routers Server (DNS1), the two hosts (Host1 and Host2), and the two routers
(Router1 and Router2). There exists another internal network (Fixed (Router1 and Router2). There exists another internal network (Fixed
Network1) inside RSU1. RSU1 has the DNS Server (DNS2), one host Network1) inside RSU1. RSU1 has the DNS Server (DNS2), one host
(Host3), the two routers (Router3 and Router4), and the collection of (Host3), the two routers (Router3 and Router4), and the collection of
servers (Server1 to ServerN) for various services in the road servers (Server1 to ServerN) for various services in the road
networks, such as the emergency notification and navigation. networks, such as the emergency notification and navigation.
Vehicle1's Router1 (a mobile router) and RSU1's Router3 (a fixed Vehicle1's Router1 (a mobile router) and RSU1's Router3 (a fixed
router) use 2001:DB8:1:1::/64 for an external link (e.g., DSRC) for router) use 2001:DB8:1:1::/64 for an external link (e.g., DSRC) for
V2I networking. Thus, one host (Host1) in Vehicle1 can communicate V2I networking. Thus, one host (Host1) in Vehicle1 can communicate
with one server (Server1) in RSU1 for a vehicular service through with one server (Server1) in RSU1 for a vehicular service through
Vehicle1's moving network, a wireless link between Vehicle1 and RSU1, Vehicle1's moving network, a wireless link between Vehicle1 and RSU1,
and RSU1's fixed network. and RSU1's fixed network.
4.3. V2V-based Internetworking
This section discusses the internetworking between the moving
networks of two neighboring vehicles via V2V communication.
(*)<..........>(*) (*)<..........>(*)
2001:DB8:1:1::/64 | | 2001:DB8:1:1::/64 | |
+------------------------------+ +------------------------------+ +------------------------------+ +------------------------------+
| v | | v | | v | | v |
| +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ |
| | Host1 | | DNS1 | |Router1| | | |Router5| | DNS3 | | Host4 | | | | Host1 | | DNS1 | |Router1| | | |Router5| | DNS3 | | Host4 | |
| +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ | | +-------+ +------+ +-------+ |
| ^ ^ ^ | | ^ ^ ^ | | ^ ^ ^ | | ^ ^ ^ |
| | | | | | | | | | | | | | | | | | | |
| v v v | | v v v | | v v v | | v v v |
skipping to change at page 12, line 34 skipping to change at page 13, line 34
| 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
4.3. 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 (DNS1), 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 (DNS3), 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 (a mobile router) and Vehicle2's Router5 (a mobile Vehicle1's Router1 (a mobile router) and Vehicle2's Router5 (a mobile
router) use 2001:DB8:1:1::/64 for an external link (e.g., DSRC) for router) use 2001:DB8:1:1::/64 for an external link (e.g., DSRC) for
V2V networking. Thus, one host (Host1) in Vehicle1 can communicate V2V networking. Thus, one host (Host1) in Vehicle1 can communicate
skipping to change at page 13, line 32 skipping to change at page 14, line 32
Figure 4: Multihop Internetworking between Two Vehicle Networks Figure 4: Multihop Internetworking between Two Vehicle Networks
Figure 4 shows multihop internetworking between the moving networks Figure 4 shows multihop internetworking between the moving networks
of two vehicles in the same VANET. For example, Host1 in Vehicle1 of two vehicles in the same VANET. For example, Host1 in Vehicle1
can communicate with Host6 in Vehicle3 via Router 5 in Vehicle2 that can communicate with Host6 in Vehicle3 via Router 5 in Vehicle2 that
is an intermediate vehicle being connected to Vehicle1 and Vehicle3 is an intermediate vehicle being connected to Vehicle1 and Vehicle3
in a linear topology as shown in the figure. in a linear topology as shown in the figure.
5. Problem Statement 5. Problem Statement
This section presents key topics such as neighbor discovery, mobility In order to specify protocols using the abovementioned architecture
management, and security & privacy. for VANETs, IPv6 core protocols have to be adapted to overcome
certain challenging aspects of vehicular networking. Since the
vehicles are likely to be moving at great speed, protocol exchanges
need to be completed in a time relatively small compared to the
lifetime of a link between a vehicle and an RSU, or between two
vehicles. This has a major impact on IPv6 neighbor discovery.
Mobility management is also vulnerable to disconnections that occur
before the completion of identity verification and tunnel management.
This is especially true given the unreliable nature of wireless
communications. Finally, and perhaps most importantly, proper
authorization for vehicular protocol messages must be assured in
order to prevent false reports of accidents or other mishaps on the
road, which would cause horrific misery in modern urban environments.
This section presents key topics such as neighbor discovery and
mobility management.
5.1. Neighbor Discovery 5.1. Neighbor Discovery
IPv6 Neighbor Discovery (IPv6 ND) [RFC4861][RFC4862] is a core part IPv6 Neighbor Discovery (IPv6 ND) [RFC4861][RFC4862] is a core part
of the IPv6 protocol suite. IPv6 ND is designed for point-to-point of the IPv6 protocol suite. IPv6 ND is designed for point-to-point
links and transit links (e.g., Ethernet). It assumes an efficient links and transit links (e.g., Ethernet). It assumes an efficient
and reliable support of multicast from the link layer for various and reliable support of multicast from the link layer for various
network operations such as MAC Address Resolution (AR) and Duplicate network operations such as MAC Address Resolution (AR) and Duplicate
Address Detection (DAD). Address Detection (DAD).
skipping to change at page 14, line 6 skipping to change at page 15, line 25
extended to vehicular networking (e.g., V2V, V2I, and V2X). Vehicles extended to vehicular networking (e.g., V2V, V2I, and V2X). Vehicles
move quickly within the communication coverage of any particular move quickly within the communication coverage of any particular
vehicle or RSU. Before the vehicles can exchange application vehicle or RSU. Before the vehicles can exchange application
messages with each other, they need to be configured with a link- messages with each other, they need to be configured with a link-
local IPv6 address or a global IPv6 address, and run IPv6 ND. local IPv6 address or a global IPv6 address, and run IPv6 ND.
The legacy DAD assumes that a node with an IPv6 address can reach any The legacy DAD assumes that a node with an IPv6 address can reach any
other node with the scope of its address at the time it claims its other node with the scope of its address at the time it claims its
address, and can hear any future claim for that address by another address, and can hear any future claim for that address by another
party within the scope of its address for the duration of the address party within the scope of its address for the duration of the address
ownership. However, the partioning and merging of VANETs makes this ownership. However, the partitioning and merging of VANETs makes
assumption frequently invalid in vehicular networks. this assumption frequently invalid in vehicular networks. The
merging and partitioning of VANETs occurs frequently in vehicular
networks. This merging and partitioning should be considered for the
IPv6 Neighbor Discovery (e.g., SLAAC). Due to the merging of VANETs,
two IPv6 addresses may conflict with each other though they were
unique before the merging. Also, the partitioning of a VANET may
make vehicles with the same prefix be physically unreachable. Also,
SLAAC should be extended to prevent IPv6 address duplication due to
the merging of VANETs. According to the merging and partitioning, a
destination vehicle (as an IP host) should be distinguished as either
an on-link host or off-link host even though the source vehicle uses
the same prefix with the destination vehicle.
The vehicular networks need to support a vehicular-network-wide DAD The vehicular networks need to support a vehicular-network-wide DAD
by defining a scope that is compatible with the legacy DAD, and two by defining a scope that is compatible with the legacy DAD, and two
vehicles can communicate with each other when there exists a vehicles can communicate with each other when there exists a
communication path over VANET or a combination of VANETs and RSUs, as communication path over VANET or a combination of VANETs and RSUs, as
shown in Figure 1. By using the vehicular-network-wide DAD, vehicles shown in Figure 1. By using the vehicular-network-wide DAD, vehicles
can assure that their IPv6 addresses are unique in the vehicular can assure that their IPv6 addresses are unique in the vehicular
network whenever they are connected to the vehicular infrastructure network whenever they are connected to the vehicular infrastructure
or become disconnected from it in the form of VANET. A vehicular or become disconnected from it in the form of VANET. A vehicular
infrastructure having RSUs and an MA can participate in the infrastructure having RSUs and an MA can participate in the
vehicular-network-wide DAD for the sake of vehicles [RFC6775]. For vehicular-network-wide DAD for the sake of vehicles [RFC6775]. For
the vehicle as an IPv6 node, deriving a unique IPv6 address from a the vehicle as an IPv6 node, deriving a unique IPv6 address from a
globally unique MAC address creates a privacy issue. Refer to globally unique MAC address creates a privacy issue. Refer to
Section 5.3 for the discussion about such a privacy issue. Section 6 for the discussion about such a privacy issue.
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 (e.g., from 1 sec to 0.5 sec) for the NA interval should decrease (e.g., from 1 sec to 0.5 sec) for the NA
messages to reach the neighboring vehicles promptly. Also, as messages to reach the neighboring vehicles promptly. Also, as
vehicle density is higher, the NA interval should increase (e.g., 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 from 0.5 sec to 1 sec) for the NA messages to reduce collision
probability with other NA messages. probability with other NA messages.
skipping to change at page 15, line 5 skipping to change at page 16, line 35
based safety applications. based safety applications.
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] do not necessarily hold in a vehicular wireless link [VIP-WAVE]
[RFC5889]. For instance, some IPv6 protocols assume symmetry in the [RFC5889]. For instance, some IPv6 protocols assume symmetry in the
connectivity among neighboring interfaces [RFC6250]. However, connectivity among neighboring interfaces [RFC6250]. However,
interference and different levels of transmission power may cause interference and different levels of transmission power may cause
asymmetric links to appear in vehicular wireless links. As a result, asymmetric links to appear in vehicular wireless links. As a result,
a new vehicular link model is required for a dynamically changing a new vehicular link model should consider the asymmetry of
vehicular wireless link. dynamically changing vehicular wireless links.
There is a relationship between a link and prefix, besides the There is a relationship between a link and a 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. on-link bit set can communicate with each other on an IP link.
However, the vehicular link model needs to define the relationship
between a link and a prefix, considering the dynamics of wireless
links and the characteristics of VANET.
A VANET can have multiple links between pairs of vehicles within A VANET can have multiple links between pairs of vehicles within
wireless communication range, as shown in Figure 4. When two wireless communication range, as shown in Figure 4. When two
vehicles belong to the same VANET, but they are out of wireless vehicles belong to the same VANET, but they are out of wireless
communication range, they cannot communicate directly with each communication range, they cannot communicate directly with each
other. Suppose that a global-scope IPv6 prefix is assigned to VANETs other. Suppose that a global-scope IPv6 prefix is assigned to VANETs
in vehicular networks. Even though two vehicles in the same VANET in vehicular networks. Even though two vehicles in the same VANET
configure their IPv6 addresses with the same IPv6 prefix, they may configure their IPv6 addresses with the same IPv6 prefix, they may
not communicate with each other not in a one hop in the same VANET not communicate with each other not in a one hop in the same VANET
because of the multihop network connectivity. Thus, in this case, because of the multihop network connectivity. Thus, in this case,
the concept of an on-link IPv6 prefix does not hold because two the concept of an on-link IPv6 prefix does not hold because two
vehicles with the same on-link IPv6 prefix cannot communicate vehicles with the same on-link IPv6 prefix cannot communicate
directly with each other. Also, when two vehicles are located in two directly with each other. Also, when two vehicles are located in two
different VANETs with the same IPv6 prefix, they cannot communicate different VANETs with the same IPv6 prefix, they cannot communicate
with each other. When these two VANETs are converged into one VANET, with each other. When these two VANETs converge to one VANET, the
the two vehicles can communicate with each other in a multihop two vehicles can communicate with each other in a multihop fashion.
fashion. Therefore, a vehicular link model should consider the
frequent partitioning and merging of VANETs due to vehicle mobility. From the previous observation, a vehicular link model should consider
the frequent partitioning and merging of VANETs due to vehicle
mobility. Therefore, the vehicular link model needs to use an on-
link prefix and off-link prefix according to the one-hop reachability
among the vehicles in an appropriate way. If the vehicles with the
same prefix are reachable with each other in one hop, the prefix
should be on-link. On the other hand, if some of the vehicles with
the same prefix are not reachable with each other in one hop due to
either the multi-hop topology in the VANET or multiple partitions,
the prefix should be off-link.
The vehicular link model needs to support the multihop routing in a The vehicular link model needs to support the multihop routing in a
connected VANET where the vehicles with the same global-scope IPv6 connected VANET where the vehicles with the same global-scope IPv6
prefix are connected in one hop or multiple hops. It also needs to prefix are connected in one hop or multiple hops. It also needs to
support the multihop routing in multiple connected VANETs via an RSU support the multihop routing in multiple connected VANETs via an RSU
that has the wireless connectivity with each VANET. For example, in that has the wireless connectivity with each VANET. For example, in
Figure 1, suppose that Vehicle1, Vehicle2, and Vehicle3 are Figure 1, suppose that Vehicle1, Vehicle2, and Vehicle3 are
configured with their IPv6 addresses based on the same global-scope configured with their IPv6 addresses based on the same global-scope
IPv6 prefix. Vehicle1 and Vehicle3 can also communicate with each IPv6 prefix. Vehicle1 and Vehicle3 can also communicate with each
other via either multi-hop V2V or multi-hop V2I2V. When two vehicles other via either multi-hop V2V or multi-hop V2I2V. When two vehicles
skipping to change at page 16, line 9 skipping to change at page 17, line 48
and under two different RSUs, they can communicate with each other and under two different RSUs, they can communicate with each other
through the relay of RSUs via V2I2V. Thus, two separate VANETs can through the relay of RSUs via V2I2V. Thus, two separate VANETs can
merge into one network via RSU(s). Also, newly arriving vehicles can merge into one network via RSU(s). Also, newly arriving vehicles can
merge two separate VANETs into one VANET if they can play a role of a merge two separate VANETs into one VANET if they can play a role of a
relay node for those VANETs. relay node for those VANETs.
5.1.2. MAC Address Pseudonym 5.1.2. MAC Address Pseudonym
For the protection of drivers' privacy, a pseudonym of a MAC address For the protection of drivers' privacy, a pseudonym of a MAC address
of a vehicle's network interface should be used, so that the MAC of a vehicle's network interface should be used, so that the MAC
address can be changed periodically. The pseudonym of a MAC address address can be changed periodically. However, although such a
affects an IPv6 address based on the MAC address, and a transport- pseudonym of a MAC address can protect some extent of privacy of a
layer (e.g., TCP) session with an IPv6 address pair. However, the vehicle, it may not be able to resist attacks on vehicle
pseudonym handling is not implemented and tested yet for applications identification by other fingerprint information, for example, the
on IP-based vehicular networking. scrambler seed embedded in IEEE 802.11-OCB frames [Scrambler-Attack].
The pseudonym of a MAC address affects an IPv6 address based on the
MAC address, and a transport-layer (e.g., TCP) session with an IPv6
address pair. However, the pseudonym handling is not implemented and
tested yet for applications on IP-based vehicular networking.
In the ETSI standards, for the sake of security and privacy, an ITS 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, and the uniqueness of the address should be should be updated, and the uniqueness of the address should be
performed through the DAD procedure. For vehicular networks with performed through the DAD procedure. For vehicular networks with
high mobility and density, this DAD should be performed efficiently high mobility and density, this DAD should be performed efficiently
with minimum overhead so that the vehicles can exchange warning with minimum overhead so that the vehicles can exchange warning
messages with each other every 0.5 second [NHTSA-ACAS-Report]. messages with each other every 0.5 second [NHTSA-ACAS-Report].
For the continuity of an end-to-end (E2E) transport-layer (e.g., TCP, For the continuity of an end-to-end (E2E) transport-layer (e.g., TCP,
UDP, and SCTP) session, with a mobility management scheme (e.g., UDP, and SCTP) session, with a mobility management scheme (e.g.,
MIPv6 and PMIPv6), the new IP address for the transport-layer session 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 can be notified to an appropriate end point, and the packets of the
session should be forwarded to their destinations with the changed session should be forwarded to their destinations with the changed
network interface identifier and IPv6 address. This mobiliy network interface identifier and IPv6 address. This mobility
management overhead for pseudonyms should be minimized for efficient management overhead for pseudonyms should be minimized for efficient
operations in vehicular networks having lots of vehicles. operations in vehicular networks having lots of vehicles.
5.1.3. Prefix Dissemination/Exchange 5.1.3. Routing
A vehicle and an RSU can have their internal network, as shown in
Figure 2 and Figure 3. In this case, nodes within the internal
networks of two vehicles (or within the internal networks of a
vehicle and an RSU) want to communicate with each other. For this
communication on the wireless link, the network prefix dissemination
or exchange is required. Either a vehicle or an RSU needs an
external network interface for its internal network, as shown in
Figure 2 and Figure 3. The vehicular ND (VND) [ID-Vehicular-ND] can
support the communication between the internal-network nodes (e.g.,
an in-vehicle device in a vehicle and a server in an RSU) with a
vehicular prefix information option. Thus, this ND extension for
routing functionality can reduce control traffic for routing in
vehicular networks without a vehicular ad hoc routing protocol (e.g.,
AODV [RFC3561] or OLSRv2 [RFC7181]).
5.1.4. Routing
For multihop V2V communications in either a VANET or VANETs via RSUs, For multihop V2V communications in either a VANET or VANETs via RSUs,
a vehicular ad hoc routing protocol (e.g., AODV and OLSRv2) may be a vehicular ad hoc routing protocol (e.g., AODV and OLSRv2) may be
required to support both unicast and multicast in the links of the required to support both unicast and multicast in the links of the
subnet with the same IPv6 prefix. However, it will be costly to run subnet with the same IPv6 prefix. However, it will be costly to run
both vehicular ND and a vehicular ad hoc routing protocol in terms of both vehicular ND and a vehicular ad hoc routing protocol in terms of
control traffic overhead [ID-Multicast-Problems]. control traffic overhead [ID-Multicast-Problems].
The merging of the IPv6 Neighbor Discovery and a VANET routing
protocol allows the efficient wireless channel utilization. A
routing protocol for VANET may cause redundant wireless frames in the
air to check the neighborhood of each vehicle and compute the routing
information in VANET with a dynamic network topology if the IPv6 ND
is used to check the neighborhood of each vehicle, and can be
extended to compute each vehicle's routing table in VANET.
Vehicular ND can be extended to accommodate routing functionality Vehicular ND can be extended to accommodate routing functionality
with a prefix discovery option. The ND extension can allow vehicles with a prefix discovery option. The ND extension can allow vehicles
to exchange their prefixes in a multihop fashion [ID-Vehicular-ND]. to exchange their prefixes in a multihop fashion [ID-Vehicular-ND].
With the exchanged prefixes, they can compute their routing table (or With the exchanged prefixes, they can compute their routing table (or
IPv6 ND's neighbor cache) for the VANETs with a distance-vector IPv6 ND's neighbor cache) for the VANETs with a distance-vector
algorithm [Intro-to-Algorithms]. algorithm [Intro-to-Algorithms].
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
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perform the DAD for the sake of the vehicle, reducing IPv6 control perform the DAD for the sake of the vehicle, reducing IPv6 control
traffic overhead in the wireless link. To prevent a hacker from traffic overhead in the wireless link. To prevent a hacker from
impersonating RSUs as bogus RSUs, RSUs and MA in the vehicular impersonating RSUs as bogus RSUs, RSUs and MA in the vehicular
infrastructure need to have secure channels via IPsec. infrastructure need to 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, RSUs needs to efficiently forward data packets from the networks, RSUs needs to efficiently forward data packets from the
wired network (or the wireless network) to a moving destination wired network (or the wireless network) to a moving destination
vehicle along its trajectory. vehicle along its trajectory.
5.3. Security and Privacy 6. Security Considerations
This section discusses security and privacy for IP-based vehicular
networking. The security and privacy are one of key components in
IP-based vehicular networking, such as neighbor discovery and
mobility management, so they need to be analyzed in depth.
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 confuse a vehicle with multiple false Sybil attack, which tries to confuse a vehicle with multiple false
identities, disturbs a vehicle in taking a safe maneuver. This sybil identities, disturbs a vehicle in taking a safe maneuver. This sybil
attack should be prevented through the cooperation between good attack should be prevented through the cooperation between good
vehicles and RSUs. Note that good vehicles are ones with valid vehicles and RSUs. Note that good vehicles are ones with valid
certificates that are determined by the authentication process with certificates that are determined by the authentication process with
an authentication server in the vehicular network. Applications on an authentication server in the vehicular network. Applications on
IP-based vehicular networking, which are resilient to such a sybil IP-based vehicular networking, which are resilient to such a sybil
attack, are not developed and tested yet. attack, are not developed and tested yet.
Security and privacy are paramount in the V2I, V2V, and V2X Security and privacy are paramount in the V2I, V2V, and V2X
networking in vehicular networks. Only authorized vehicles should be networking in vehicular networks. Only authorized vehicles should be
allowed to use vehicular networking. Also, in-vehicle devices and allowed to use vehicular networking. Also, in-vehicle devices and
mobile devices in a vehicle need to communicate with other in-vehicle mobile devices in a vehicle need to communicate with other in-vehicle
devices and mobile devices in another vehicle, and other servers in devices and mobile devices in another vehicle, and other servers in
an RSU in a secure way. an RSU in a secure way. Even a perfectly authorized and legitimate
vehicle may be hacked to run malicious applications to track and
collect other vehicles' information. For this case, an attack
mitigation process may be required to reduce the aftermath of the
malicious behaviors.
A Vehicle Identification Number (VIN) and a user certificate along A Vehicle Identification Number (VIN) and a user certificate along
with in-vehicle device's identifier generation can be used to with in-vehicle device's identifier generation can be used to
efficiently authenticate a vehicle or a user through a road efficiently authenticate a vehicle or a user through a road
infrastructure node (e.g., RSU) connected to an authentication server infrastructure node (e.g., RSU) connected to an authentication server
in TCC. Also, Transport Layer Security (TLS) certificates can be in TCC. Also, Transport Layer Security (TLS) certificates can be
used for secure E2E vehicle communications. used for secure E2E vehicle communications.
For secure V2I communication, a secure channel between a mobile For secure V2I communication, a secure channel between a mobile
router in a vehicle and a fixed router in an RSU should be router in a vehicle and a fixed router in an RSU should be
skipping to change at page 19, line 31 skipping to change at page 21, line 28
ND packets are disseminated over the VANET and vehicular network ND packets are disseminated over the VANET and vehicular network
including the RSUs and the MA. The vehicles and RSUs need to filter including the RSUs and the MA. The vehicles and RSUs need to filter
out suspicious ND traffic in advance. out suspicious ND traffic in advance.
For the mobility management, a malicious vehicle can construct For the mobility management, a malicious vehicle can construct
multiple virtual bogus vehicles, and register them with the RSU and multiple virtual bogus vehicles, and register them with the RSU and
the MA. This registration makes the RSU and MA waste their the MA. This registration makes the RSU and MA waste their
resources. The RSU and MA need to determine whether a vehicle is resources. The RSU and MA need to determine whether a vehicle is
genuine or bogus in the mobility management. genuine or bogus in the mobility management.
6. Security Considerations
This document discussed security and privacy for IP-based vehicular
networking.
The security and privacy for key components in IP-based vehicular
networking, such as neighbor discovery and mobility management, need
to be analyzed in depth.
7. Informative References 7. Informative References
[Automotive-Sensing] [Automotive-Sensing]
Choi, J., Va, V., Gonzalez-Prelcic, N., Daniels, R., R. Choi, J., Va, V., Gonzalez-Prelcic, N., Daniels, R., R.
Bhat, C., and R. W. Heath, "Millimeter-Wave Vehicular Bhat, C., and R. W. Heath, "Millimeter-Wave Vehicular
Communication to Support Massive Automotive Sensing", Communication to Support Massive Automotive Sensing",
IEEE Communications Magazine, December 2016. IEEE Communications Magazine, December 2016.
[CA-Cruise-Control] [CA-Cruise-Control]
California Partners for Advanced Transportation Technology California Partners for Advanced Transportation Technology
skipping to change at page 20, line 25 skipping to change at page 22, line 12
Networks", International Workshop on Device Centric Cloud Networks", International Workshop on Device Centric Cloud
(DC2), March 2016. (DC2), March 2016.
[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 Technical Committee Intelligent Transport Systems,
"Intelligent Transport Systems (ITS); Vehicular
Communications; GeoNetworking; Part 6: Internet
Integration; Sub-part 1: Transmission of IPv6 Packets over
GeoNetworking Protocols", ETSI EN 302 636-6-1, October
2013.
[ETSI-GeoNetworking]
ETSI Technical Committee Intelligent Transport Systems,
"Intelligent Transport Systems (ITS); Vehicular
Communications; GeoNetworking; Part 4: Geographical
addressing and forwarding for point-to-point and point-to-
multipoint communications; Sub-part 1: Media-Independent
Functionality", ETSI EN 302 636-4-1, May 2014.
[EU-2008-671-EC] [EU-2008-671-EC]
European Union, "Commission Decision of 5 August 2008 on European Union, "Commission Decision of 5 August 2008 on
the Harmonised Use of Radio Spectrum in the 5875 - 5905 the Harmonised Use of Radio Spectrum in the 5875 - 5905
MHz Frequency Band for Safety-related Applications of MHz Frequency Band for Safety-related Applications of
Intelligent Transport Systems (ITS)", EU 2008/671/EC, Intelligent Transport Systems (ITS)", EU 2008/671/EC,
August 2008. August 2008.
[FirstNet] [FirstNet]
U.S. National Telecommunications and Information U.S. National Telecommunications and Information
Administration (NTIA), "First Responder Network Authority Administration (NTIA), "First Responder Network Authority
skipping to change at page 24, line 5 skipping to change at page 25, line 22
Du, "SAINT+: Self-Adaptive Interactive Navigation Tool+ Du, "SAINT+: Self-Adaptive Interactive Navigation Tool+
for Emergency Service Delivery Optimization", for Emergency Service Delivery Optimization",
IEEE Transactions on Intelligent Transportation Systems, IEEE Transactions on Intelligent Transportation Systems,
June 2017. June 2017.
[SANA] Hwang, T. and J. Jeong, "SANA: Safety-Aware Navigation [SANA] Hwang, T. and J. Jeong, "SANA: Safety-Aware Navigation
Application for Pedestrian Protection in Vehicular Application for Pedestrian Protection in Vehicular
Networks", Springer Lecture Notes in Computer Science Networks", Springer Lecture Notes in Computer Science
(LNCS), Vol. 9502, December 2015. (LNCS), Vol. 9502, December 2015.
[Scrambler-Attack]
Bloessl, B., Sommer, C., Dressier, F., and D. Eckhoff,
"The Scrambler Attack: A Robust Physical Layer Attack on
Location Privacy in Vehicular Networks", IEEE 2015
International Conference on Computing, Networking and
Communications (ICNC), February 2015.
[Timing-Attack]
Matte, C., Cunche, M., Rousseau, F., and M. Vanhoef,
"Defeating MAC Address Randomization Through Timing
Attacks", ACM the 9th ACM Conference on Security & Privacy
in Wireless and Mobile Networks (WiSec '16), July 2016.
[Truck-Platooning] [Truck-Platooning]
California Partners for Advanced Transportation Technology California Partners for Advanced Transportation Technology
(PATH), "Automated Truck Platooning", [Online] Available: (PATH), "Automated Truck Platooning", [Online] Available:
http://www.path.berkeley.edu/research/automated-and- http://www.path.berkeley.edu/research/automated-and-
connected-vehicles/truck-platooning, 2017. connected-vehicles/truck-platooning, 2017.
[TS-23.285-3GPP] [TS-23.285-3GPP]
3GPP, "Architecture Enhancements for V2X Services", 3GPP 3GPP, "Architecture Enhancements for V2X Services", 3GPP
TS 23.285, June 2018. TS 23.285, June 2018.
skipping to change at page 25, line 5 skipping to change at page 27, line 5
[WAVE-1609.3] [WAVE-1609.3]
IEEE 1609 Working Group, "IEEE Standard for Wireless IEEE 1609 Working Group, "IEEE Standard for Wireless
Access in Vehicular Environments (WAVE) - Networking Access in Vehicular Environments (WAVE) - Networking
Services", IEEE Std 1609.3-2016, April 2016. Services", IEEE Std 1609.3-2016, April 2016.
[WAVE-1609.4] [WAVE-1609.4]
IEEE 1609 Working Group, "IEEE Standard for Wireless IEEE 1609 Working Group, "IEEE Standard for Wireless
Access in Vehicular Environments (WAVE) - Multi-Channel Access in Vehicular Environments (WAVE) - Multi-Channel
Operation", IEEE Std 1609.4-2016, March 2016. Operation", IEEE Std 1609.4-2016, March 2016.
Appendix A. Changes from draft-ietf-ipwave-vehicular-networking-10 Appendix A. Changes from draft-ietf-ipwave-vehicular-networking-11
The following changes are made from draft-ietf-ipwave-vehicular- The following changes are made from draft-ietf-ipwave-vehicular-
networking-10: networking-11:
o This version is revised based on the comments from Charlie Perkins o This version is revised based on the comments from Charlie Perkins
and Sri Gundavelli. and Sandra Cespedes.
o Many editorial comments and questions from Charlie Perkins are o In Section 5, the problem statement is revisd with easily
addressed in this document. identifiable problems.
o According to Sri Gundavelli's comments, the solution text and RFC o In Section 1, the description of GeoNetworking (GN) protocols
8505 reference for the vehicular ND are deleted from Section 5.1 (i.e., geographic routing) is removed because the GN protocols are
in this document. not relevant to the IPWAVE's use cases.
o In Section 2, the terms of OCB, Context-Awareness, Platooning, and
Class-Based Safety Plan are clarified.
o In Section 2, the definition of an RSU is revised so that it can
accommodate multiple routers (or switches) and servers (including
DNS server and edge computing server) as an edge computing system
because the RSU is regularly a router or switch.
o In Section 4.1, a general vehicular network architecture is
proposed for the problem statement along with Figure 1. This
figure clarifies that a single subnet prefix can span multiple
vehicles that construct a subnet. Also, some components in the
vehicular network architecture may not be needed such as Vehicular
Cloud, Traffic Control Center, and Mobility Anchor.
o In Section 5.1.1, the motivation of a new link model as a
vehicular link model is added. The "on-link" and "off-link" for
prefixes are classified according to the subnet topology of VANET.
o In Section 5.1.1, the merging and partitioning of VANETs is
described, and the requirements of the IPv6 ND are addressed for
the merging and partitioning as a problem statement.
o In Section 5.1.2, a citation of [Scrambler-Attack], which uses the
scrambler seed in the IEEE 802.11-OCB frames as fingerprint
information, is added to show the insufficiency of the MAC address
pseudonym for privacy.
o In Section 5.1, the subsection of Prefix Dissemination/Exchange is
removed because the Prefix Dissemination/Exchange subsection
discusses a solution rather than a problem or requirement.
o In Section 5.1.3, the motivation of merging the IPv6 ND and a
VANET routing protocol is explained to improve wireless channel
utilization by removing redundant neighbor information exchange.
o The text of the problems and requirements of security and privacy
in vehicular networks are moved to Section 6.
o In Section 6, the compromise of a perfectly authorized and
legitimate vehicle is described as a security problem to be
considered.
o In Section 3.3, the description of Vehicle-to-Pedestrian (V2P) is
concised to deliver the clear concept of the direct communication
between a vehicle and a pedestrian.
Appendix B. Acknowledgments Appendix B. 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 the MSIT (Ministry of Science and This work was supported in part by the MSIT (Ministry of Science and
ICT), Korea, under the ITRC (Information Technology Research Center) ICT), Korea, under the ITRC (Information Technology Research Center)
support program (IITP-2019-2017-0-01633) supervised by the IITP support program (IITP-2019-2017-0-01633) supervised by the IITP
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