IPv6 Wireless Access in Vehicular Environments (IPWAVE): Problem Statement and Use Cases
Department of Computer Science and Engineering
Sungkyunkwan University2066 Seobu-Ro, Jangan-GuSuwonGyeonggi-Do16419Republic of Korea+82 31 299 4957+82 31 290 7996pauljeong@skku.eduhttp://iotlab.skku.edu/people-jaehoon-jeong.php
Internet
IPWAVE Working GroupInternet-Draft
This document discusses the problem statement and use cases of
IPv6-based vehicular networking for Intelligent Transportation Systems (ITS).
The main scenarios of vehicular communications are vehicle-to-vehicle (V2V),
vehicle-to-infrastructure (V2I), and vehicle-to-everything (V2X) communications.
First, this document explains use cases using V2V, V2I, and V2X networking.
Next, it makes a problem statement about key aspects in IPv6-based vehicular
networking, such as IPv6 Neighbor Discovery, Mobility Management, and
Security & Privacy. For each key aspect, this document specifies
requirements for IPv6-based vehicular networking.
Vehicular networking studies have mainly focused on improving safety and
efficiency, and also enabling entertainment in vehicular networks. The Federal
Communications Commission (FCC) in the US allocated wireless channels
for Dedicated Short-Range Communications (DSRC)
in the Intelligent Transportation Systems (ITS) with the frequency band of
5.850 - 5.925 GHz (i.e., 5.9 GHz band). DSRC-based wireless communications
can support vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I),
and vehicle-to-everything (V2X) networking.
The European Union (EU) allocated radio spectrum for safety-related and
non-safety-related applications of ITS with the frequency band of
5.875 - 5.905 GHz, as part of the Commission Decision 2008/671/EC .
For direct inter-vehicular wireless connectivity, IEEE has amended WiFi
standard 802.11 to enable driving safety services based on DSRC
for the Wireless Access in Vehicular Environments (WAVE)
system. The Physical Layer (L1) and Data Link Layer (L2) issues are addressed
in IEEE 802.11p
for the PHY and MAC of the DSRC, while IEEE 1609.2
covers security aspects, IEEE 1609.3
defines related services at network and transport layers, and IEEE 1609.4
specifies the multi-channel operation.
IEEE 802.11p was first a separate amendment, but was later rolled into
the base 802.11 standard (IEEE 802.11-2012) as IEEE 802.11 Outside the Context
of a Basic Service Set (OCB) in 2012 .
Along with these WAVE standards, IPv6 and Mobile
IPv6 protocols (e.g., Mobile IPv6 (MIPv6) ,
and Proxy MIPv6 (PMIPv6) ) can be applied to
vehicular networks. In addition, ISO has approved a standard specifying the
IPv6 network protocols and services to be used for Communications Access
for Land Mobiles (CALM) .
This document describes use cases and a problem statement about
IPv6-based vehicular networking for ITS, which is named IPv6 Wireless Access in
Vehicular Environments (IPWAVE).
First, it introduces the use cases for using V2V, V2I, and V2X networking
in ITS.
Next, it makes a problem statement about key aspects in IPWAVE, namely,
IPv6 Neighbor Discovery (ND), Mobility Management (MM), and Security &
Privacy (SP).
For each key aspect of the problem statement, this document specifies
requirements for IPv6-based vehicular networking.
This document is intended to motivate development of key protocols for IPWAVE.
This document uses the terminology described in .
In addition, the following terms are defined below:
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 .
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 .
Edge Computing (EC): It is the local computing near an access network (i.e.,
edge network) for the sake of vehicles and pedestrians.
Edge Computing Device (ECD): It is a computing device (or server) for edge computing
for the sake of vehicles and pedestrians.
Edge Network (EN): In is an access network that has an IP-RSU for wireless
communication with other vehicles having an IP-OBU and wired communication
with other network devices (e.g., routers, IP-RSUs, ECDs, servers, and MA).
It may have a radio receiver of Global Positioning System (GPS) for its
position recognition and the localization service for the sake of vehicles.
IP-OBU: "Internet Protocol On-Board Unit": An IP-OBU denotes a computer
situated in a vehicle such as a car, bicycle, or similar. It has at least
one IP interface that runs in mode OCB of 802.11 and has an "OBU" transceiver.
Also, it may have an IP interface that runs in Cellular V2X (C-V2X)
.
See the definition of the term "OBU" in .
IP-RSU: "IP Roadside Unit": An IP-RSU is situated along the road. It has
at least two distinct IP-enabled interfaces. The wireless PHY/MAC layer of
at least one of its IP-enabled interfaces is configured to operate in
802.11-OCB mode. An IP-RSU communicates with the IP-OBU over an 802.11
wireless link operating in OCB mode. Also, it may have an IP interface that
runs in C-V2X along with an "RSU" transceiver. An IP-RSU is similar to an
Access Network Router (ANR), defined in , and
a Wireless Termination Point (WTP), defined in .
See the definition of the term "RSU" in .
LiDAR: "Light Detection and Ranging". It is a scanning device
to measure a distance to an object by emitting pulsed laser light and
measuring the reflected pulsed light.
Mobility Anchor (MA): A node that maintains IPv6 addresses and
mobility information of vehicles in a road network to support
their IPv6 address autoconfiguration and mobility management
with a binding table.
An MA has End-to-End (E2E) connections with IP-RSUs under its control for the
address autoconfiguration and mobility management of the vehicles.
This MA can play a role of a Local Mobility Anchor (LMA) in PMIPv6
for vehicles moving in the road network .
OCB: "Outside the Context of a Basic Service Set - BSS". It is a mode
of operation in which a Station (STA) is not a member of a BSS and does not
utilize IEEE Std 802.11 authentication, association, or data
confidentiality .
802.11-OCB: It refers to the mode specified in IEEE Std 802.11-2016
when the MIB attribute dot11OCBActivited
is 'true'.
Platooning: Moving vehicles can be grouped together to reduce
air-resistance for energy efficiency and reduce the number of drivers such
that only the leading vehicle has a driver and the other vehicles are autonomous
vehicles without a driver and closely following the leading vehicle .
Traffic Control Center (TCC): A node that maintains road
infrastructure information (e.g., IP-RSUs, traffic signals, and
loop detectors), vehicular traffic statistics (e.g., average
vehicle speed and vehicle inter-arrival time per road segment),
and vehicle information (e.g., a vehicle's identifier, position,
direction, speed, and trajectory as a navigation path). TCC is
included in a vehicular cloud for vehicular networks.
Vehicle: A Vehicle in this document is a node that has an IP-OBU
for wireless communication with other vehicles and IP-RSUs.
It has a radio navigation receiver of Global Positioning System
(GPS) for efficient navigation.
Vehicular Ad Hoc Network (VANET): A network that consists of vehicles
interconnected by wireless communication.
Two vehicles in a VANET can communicate with each other using
other vehicles as relays even where they are out of one-hop
wireless communication range.
Vehicular Cloud: A cloud infrastructure for vehicular networks, having
compute nodes, storage nodes, and network forwarding elements
(e.g., switch and router).
Vehicle Detection Loop (i.e., Loop Detector): An inductive device
used for detecting vehicles passing or arriving at a certain point,
for instance, at an intersection with traffic lights or at a ramp
toward a highway.
The relatively crude nature of the loop's structure means that only
metal masses above a certain size are capable of triggering the detection.
V2D: "Vehicle to Device". It is the wireless communication between
a vehicle and a device (e.g., IoT device).
V2P: "Vehicle to Pedestrian". It is the wireless communication
between a vehicle and a pedestrian's mobile device (e.g., smartphone).
V2I2P: "Vehicle to Infrastructure to Pedestrian". It is the wireless
communication between a vehicle and a pedestrian's mobile device
(e.g., smartphone) via an infrastructure node (e.g., IP-RSU).
V2I2V: "Vehicle to Infrastructure to Vehicle". It is the wireless
communication between a vehicle and another vehicle via an
infrastructure node (e.g., IP-RSU).
VIP: "Vehicular Internet Protocol". It is an IPv6 extension for vehicular
networks including V2V, V2I, and V2X.
VMM: "Vehicular Mobility Management". It is an IPv6-based mobility
management for vehicular networks.
VND: "Vehicular Neighbor Discovery". It is an IPv6 ND extension for
vehicular networks.
VSP: "Vehicular Security and Privacy". It is an IPv6-based security and
privacy for vehicular networks.
WAVE: "Wireless Access in Vehicular Environments" .
This section explains use cases of V2V, V2I, and V2X networking.
The use cases of the V2X networking exclude the ones of the V2V
and V2I networking, but include Vehicle-to-Pedestrian (V2P) and
Vehicle-to-Device (V2D).
Since IP is widely used among various computing devices in the
Internet, it is expected that the use cases in this section need
to work on top of IPv6 as the network layer protocol. Thus, the
IPv6 for these use cases should be extended for vehicular IPv6
such that the IPv6 can support the functions of the network
layer protocol such as Vehicular Neighbor Discovery (VND),
Vehicular Mobility Management (VMM), and Vehicular Security and
Privacy (VSP) in vehicular networks.
Refer to for
the problem statement of the requirements of the vehicular IPv6.
The use cases of V2V networking discussed in this section include
Context-aware navigation for driving safety and collision avoidance;Cooperative adaptive cruise control in an urban roadway;Platooning in a highway;Cooperative environment sensing.
These four techniques will be important elements for self-driving vehicles.
Context-Aware Safety Driving (CASD) navigator
can help drivers to drive safely by alerting the drivers about
dangerous obstacles and situations. That is, CASD navigator displays
obstacles or neighboring vehicles relevant to possible collisions in
real-time through V2V networking. CASD provides vehicles with a
class-based automatic safety action plan, which considers three
situations, namely, the Line-of-Sight unsafe, Non-Line-of-Sight
unsafe, and safe situations. This action plan can be put into action
among multiple vehicles using V2V networking.
Cooperative Adaptive Cruise Control (CACC)
helps vehicles to adapt their
speed autonomously through V2V communication among vehicles according
to the mobility of their predecessor and successor vehicles in an
urban roadway or a highway. Thus, CACC can help adjacent vehicles to
efficiently adjust their speed in an interactive way through V2V networking
in order to avoid collision.
Platooning allows a series of
vehicles (e.g., trucks) to follow each other very closely.
Trucks can use V2V communication in addition to
forward sensors in order to maintain constant clearance between two
consecutive vehicles at very short gaps (from 3 meters to 10 meters).
Platooning can maximize the throughput of vehicular traffic in
a highway and reduce the gas consumption because the leading vehicle
can help the following vehicles to experience less air resistance.
Cooperative-environment-sensing use cases suggest that vehicles can
share environmental information from various vehicle-mounted sensors,
such as radars, LiDARs, and cameras with other vehicles and pedestrians.
introduces a millimeter-wave
vehicular communication for massive automotive sensing.
A lot of data can be generated by those sensors, and
these data typically need to be routed to different destinations.
In addition, from the perspective of driverless vehicles, it is
expected that driverless vehicles can be mixed with driver-operated
vehicles. Through the cooperative environment sensing, driver-operated
vehicles can use environmental information sensed by driverless vehicles
for better interaction with the other vehicles and environment.
To support the applications of these V2V use cases, the functions of IPv6
such as VND and VSP are prerequisite for the IPv6-based packet exchange
and the secure, safe communication between two vehicles.
The use cases of V2I networking discussed in this section include
Navigation service;Energy-efficient speed recommendation service;Accident notification service.
A navigation service, for example, the Self-Adaptive Interactive Navigation Tool
(SAINT) , using V2I networking interacts
with TCC for the large-scale/long-range road traffic optimization and can guide
individual vehicles for appropriate navigation paths in real time.
The enhanced version of SAINT can
give fast moving paths to emergency vehicles (e.g., ambulance
and fire engine) to let them reach an accident spot while redirecting other vehicles
near the accident spot into efficient detour paths.
A TCC can recommend an energy-efficient speed to a vehicle
that depends on its traffic environment.
studies fuel-efficient route
and speed plans for platooned trucks.
The emergency communication between accident vehicles (or emergency
vehicles) and TCC can be performed via either IP-RSU or 4G-LTE networks.
The First Responder Network Authority (FirstNet)
is provided by the US government to
establish, operate, and maintain an interoperable public safety
broadband network for safety and security network services, e.g.,
emergency calls. The construction of the nationwide FirstNet network
requires each state in the US to have a Radio Access Network (RAN)
that will connect to the FirstNet's network core.
The current RAN is mainly constructed by 4G-LTE for the communication
between a vehicle and an infrastructure node (i.e., V2I)
, but it is expected that DSRC-based vehicular
networks will be available for V2I and V2V in near future.
To support the applications of these V2I use cases, the functions of IPv6
such as VND, VMM, and VSP are prerequisite for the IPv6-based packet exchange,
the transport-layer session continuity, and the secure, safe communication
between a vehicle and a server in the vehicular cloud.
The use case of V2X networking discussed in this section is
pedestrian protection service.
A pedestrian protection service, such as Safety-Aware Navigation
Application (SANA) , using V2I2P networking
can reduce the collision of a vehicle and a pedestrian carrying a
smartphone equipped with a network device for wireless communication
(e.g., WiFi) with an IP-RSU. Vehicles and pedestrians can also
communicate with each other via an IP-RSU. An edge computing device
behind the IP-RSU can collect the mobility information from vehicles
and pedestrians, compute wireless communication scheduling for the
sake of them. This scheduling can save the battery of each
pedestrian's smartphone by allowing it to work in sleeping mode
before the communication with vehicles, considering their mobility.
For Vehicle-to-Pedestrian (V2P), a vehicle can directly communicate
with a pedestrian's smartphone by V2X without IP-RSU relaying.
Light-weight mobile nodes such as bicycles may also communicate
directly with a vehicle for collision avoidance using V2V.
To support the applications of these V2X use cases, the functions of IPv6
such as VND, VMM, and VSP are prerequisite for the IPv6-based packet exchange,
the transport-layer session continuity, and the secure, safe communication
between a vehicle and a pedestrian either directly or indirectly via an IP-RSU.
This section describes an exemplary vehicular network architecture supporting V2V, V2I, and V2X communications
in vehicular networks.
It describes an internal network within a vehicle or an edge network
(called EN). It explains not only the internetworking between the
internal networks of a vehicle and an EN via wireless links, but also
the internetworking between the internal networks of two vehicles
via wireless links.
shows an
exemplary vehicular network architecture for V2I and V2V in
a road network.
The vehicular network architecture contains vehicles, IP-RSUs,
Vehicular Cloud, Traffic Control Center, and Mobility Anchor as
components. However, some components in the vehicular network
architecture may not be needed for vehicular networks,
such as Vehicular Cloud, Traffic Control Center, and Mobility Anchor.
As shown in this figure, IP-RSUs as routers and vehicles with IP-OBU
have wireless media interfaces for VANET.
Furthermore, the wireless media interfaces are
autoconfigured with a global IPv6 prefix (e.g., 2001:DB8:1:1::/64)
to support both V2V and V2I networking.
Note that 2001:DB8::/32 is a documentation prefix
for example prefixes in this document, and also that any routable
IPv6 address needs to be routable in a VANET and a vehicular network
including IP-RSUs.
For IPv6 packets transported over IEEE 802.11-OCB,
specifies several details, including
Maximum Transmission Unit (MTU), frame format, link-local address,
address mapping for unicast and multicast, stateless autoconfiguration, and
subnet structure.
An Ethernet Adaptation (EA) layer is in charge of transforming some
parameters between 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. This IPv6 over 802.11-OCB can be used for both V2V and V2I
in IPv6-based vehicular networks.
In ,
three IP-RSUs (IP-RSU1, IP-RSU2, and IP-RSU3) are deployed in the road
network and are connected with each other through the wired networks
(e.g., Ethernet), which are part of a Vehicular Cloud.
A Traffic Control Center (TCC) is connected to the Vehicular Cloud for
the management of IP-RSUs and vehicles in the road network.
A Mobility Anchor (MA) may be located in the TCC as a mobility management
controller, which is a controller for the mobility management of vehicles.
Vehicle2, Vehicle3, and Vehicle4 are wirelessly connected to IP-RSU1,
IP-RSU2, and IP-RSU3, respectively.
The three wireless networks of IP-RSU1, IP-RSU2, and IP-RSU3 can belong to three
different subnets (i.e., Subnet1, Subnet2, and Subnet3), respectively.
Those three subnets use three different prefixes (i.e., Prefix1, Prefix2,
and Prefix3).
A single subnet prefix can span multiple vehicles in VANET. For example,
in , 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 ), vehicles can construct
a connected VANET (with an arbitrary graph topology) and can communicate with
each other via V2V communication.
Vehicle1 can communicate with Vehicle2 via V2V communication, and
Vehicle2 can communicate with Vehicle3 via V2V communication because
they are within the wireless communication range for each other.
On the other hand, Vehicle3 can communicate with
Vehicle4 via the vehicular infrastructure (i.e., IP-RSU2 and IP-RSU3) by
employing V2I (i.e., V2I2V) communication because they are not within
the wireless communication range for each other.
An IPv6 mobility solution is needed in vehicular networks so that
a vehicle's TCP session can be continued while it moves from an
IP-RSU's wireless coverage to another IP-RSU's wireless coverage.
In ,
assuming that Vehicle2 has a TCP session with a corresponding node
in the vehicular cloud, Vehicle2 can move from IP-RSU1's wireless
coverage to IP-RSU2's wireless coverage. In this case, a handover for
Vehicle2 needs to be performed by either a host-based mobility
management scheme (e.g., MIPv6 ) or a
network-based mobility management scheme (e.g., PMIPv6
).
In the host-based mobility scheme, an IP-RSU plays a role of a home
agent in a visited network. On the other hand, in the network-based
mobility scheme, an MA plays a role of a mobility management
controller such as a Local Mobility Anchor (LMA) in PMIPv6, and an
IP-RSU plays a role of an access router such as a Mobile Access Gateway
(MAG) in PMIPv6 .
In vehicular networks, the control plane can be separated from
the data plane for efficient mobility management and data forwarding.
The separation of the control plane and data plane can be performed
by the Software-Defined Networking (SDN) .
An MA can configure and monitor its IP-RSUs and vehicles for mobility
management, location management, and security services in an
efficient way.
The mobility information of a GPS receiver mounted in its vehicle
(e.g., position, speed, and direction) can be used to accommodate
mobility-aware proactive handover schemes, which can perform the
handover of a vehicle according to its mobility and the wireless
signal strength of a vehicle and an IP-RSU in a proactive way.
Vehicles can use the TCC as their Home Network having a home agent for mobility
management as in MIPv6 and PMIPv6 ,
so the TCC maintains the mobility information of vehicles for location management.
IP tunneling over the wireless link should be avoided for performance efficiency.
Also, in vehicular networks, asymmetric links sometimes exist and must be
considered for wireless communications such as V2V and V2I.
This section discusses the internetworking between a vehicle's
internal network (i.e., moving network) and an EN's internal
network (i.e., fixed network) via V2I communication.
Note that an EN can accommodate multiple routers (or switches)
and servers (e.g., ECDs, navigation server, and DNS server)
in its internal network.
A vehicle's internal network often uses Ethernet to interconnect
Electronic Control Units (ECUs) in the vehicle. The internal
network can support WiFi and Bluetooth to accommodate a driver's
and passenger's mobile devices (e.g., smartphone or tablet).
The network topology and subnetting depend on each vendor's
network configuration for a vehicle and an EN.
It is reasonable to consider the interaction between the internal
network and an external network within another vehicle or an EN.
As shown in , as internal
networks, a vehicle's moving network and an EN's fixed network
are self-contained networks having multiple subnets and having
an edge router (e.g., IP-OBU and IP-RSU) for the communication with
another vehicle or another EN.
Internetworking between two internal networks via V2I communication
requires the exchange of the network parameters and the network
prefixes of the internal networks.
also shows internetworking
between the vehicle's moving network and the EN's fixed network.
There exists an internal network (Moving Network1) inside Vehicle1.
Vehicle1 has two hosts (Host1 and Host2), and two routers (IP-OBU1
and Router1). There exists another internal network (Fixed Network1)
inside EN1. EN1 has one host (Host3), two routers (IP-RSU1 and
Router2), and the collection of servers (Server1 to ServerN) for
various services in the road networks, such as the emergency
notification and navigation. Vehicle1's IP-OBU1 (as a mobile router)
and EN1's IP-RSU1 (as a fixed router) use 2001:DB8:1:1::/64 for an
external link (e.g., DSRC) for V2I networking.
Thus, a host (Host1) in Vehicle1 can communicate with a server
(Server1) in EN1 for a vehicular service through Vehicle1's moving
network, a wireless link between IP-OBU1 and IP-RSU1, and EN1's fixed
network.
For an IPv6 communication between an IP-OBU and an IP-RSU or between
two neighboring IP-OBUs, network parameters need to be shared
among them, such as MAC layer and IPv6 layer information.
The MAC layer information includes wireless link layer parameters,
transmission power level, the MAC address of an external network
interface for the internetworking with another IP-OBU or IP-RSU.
The IPv6 layer information includes the IPv6 address and network
prefix of an external network interface for the internetworking with
another IP-OBU or IP-RSU.
Through the exchange of network parameters and network prefixes among
internal networks, packets can be transmitted between the vehicle's moving
network and the EN's fixed network. Thus, V2I requires an efficient
exchange protocol for network parameters and an efficient routing protocol
for network prefixes.
This section discusses the internetworking between the moving
networks of two neighboring vehicles via V2V communication.
shows internetworking
between the moving networks of two neighboring vehicles. There
exists an internal network (Moving Network1) inside Vehicle1.
Vehicle1 has two hosts (Host1 and Host2), and two routers
(IP-OBU1 and Router1). There exists another internal network
(Moving Network2) inside Vehicle2. Vehicle2 has two hosts
(Host3 and Host4), and two routers (IP-OBU2 and Router2).
Vehicle1's IP-OBU1 (as a mobile router) and Vehicle2's IP-OBU2
(as a mobile router) use 2001:DB8:1:1::/64 for an external link
(e.g., DSRC) for V2V networking.
Thus, a host (Host1) in Vehicle1 can communicate with another host
(Host3) in Vehicle2 for a vehicular service through Vehicle1's
moving network, a wireless link between IP-OBU1 and IP-OBU2, and
Vehicle2's moving network.
shows multihop
internetworking between the moving networks of two vehicles in the
same VANET. For example, Host1 in Vehicle1 can communicate with
Host3 in Vehicle3 via IP-OBU1 in Vehicle1, IP-OBU2 in Vehicle2, and
IP-OBU3 in Vehicle3 in a linear topology as shown in the figure.
In order to specify protocols using the abovementioned architecture
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 IP-RSU, or between two vehicles. This
has a major impact on IPv6 Neighbor Discovery (ND). Mobility
Management (MM) is also vulnerable to disconnections that occur before
the completion of identity verification and tunnel management. This
is especially true given the unreliable nature of wireless
communications. Thus, this section presents key topics such as
neighbor discovery and mobility management.
IPv6 ND
is a core part of the IPv6 protocol suite. IPv6 ND is designed for
point-to-point links and transit links (e.g., Ethernet). It assumes
an efficient and reliable support of multicast from the link layer
for various network operations such as MAC Address Resolution (AR)
and Duplicate Address Detection (DAD).
Vehicles move quickly within the communication coverage of any
particular vehicle or IP-RSU. Before the vehicles can exchange
application messages with each other, they need to be configured
with a link-local IPv6 address or a global IPv6 address, and run
IPv6 ND.
The legacy DAD assumes that a node with an IPv6 address can reach any
other node with the scope of its address at the time it claims its address,
and can hear any future claim for that address by another party within
the scope of its address for the duration of the address ownership.
However, the partitioning and merging of VANETs makes this assumption
frequently invalid in vehicular networks.
The merging and partitioning of VANETs occurs frequently in vehicular
networks. This merging and partitioning should be considered for the
IPv6 ND such as IPv6 Stateless Address Autoconfiguration (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 needs to prevent IPv6 address
duplication due to the merging of VANETs. According to the merging and
partitioning, a destination vehicle (as an IPv6 host) needs to be
distinguished as either an on-link host or an off-link host even though
the source vehicle uses the same prefix with the destination vehicle.
To efficiently prevent the IPv6 address duplication due to the VANET
partitioning and merging from happing in vehicular networks, the
vehicular networks need to support a vehicular-network-wide DAD by
defining a scope that is compatible with the legacy DAD. In this case,
two vehicles can communicate with each other when there exists a
communication path over VANET or a combination of VANETs and IP-RSUs,
as shown in .
By using the vehicular-network-wide DAD, vehicles can assure that
their IPv6 addresses are unique in the vehicular network whenever
they are connected to the vehicular infrastructure or become
disconnected from it in the form of VANET.
ND time-related parameters such as router lifetime and Neighbor
Advertisement (NA) interval need to be adjusted for high-speed
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
messages to reach the neighboring vehicles promptly. Also, as
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.
For IPv6-based safety applications (e.g., context-aware navigation,
adaptive cruise control, and platooning) in vehicular networks,
the delay-bounded data delivery is critical. Implementations for
such applications are not available yet. IPv6 ND needs to
efficiently work to support IPv6-based safety applications.
A prefix model for a vehicular network needs to facilitate the
communication between two vehicles with the same prefix regardless
of the vehicular network topology as long as there exist
bidirectional E2E paths between them in the vehicular
network including VANETs and IP-RSUs.
This prefix model allows vehicles with the same prefix to
communicate with each other via a combination of multihop V2V and
multihop V2I with VANETs and IP-RSUs.
IPv6 protocols work under certain assumptions for the link model that
do not necessarily hold in a vehicular wireless link
.
For instance, some IPv6 protocols assume symmetry in the connectivity
among neighboring interfaces .
However, radio interference and different levels of transmission power
may cause asymmetric links to appear in vehicular wireless links.
As a result, a new vehicular link model needs to consider the asymmetry
of dynamically changing vehicular wireless links.
There is a relationship between a link and a prefix, besides the
different scopes that are expected from the link-local and global types
of IPv6 addresses. In an IPv6 link, it is assumed that all interfaces
which are configured with the same subnet prefix and with on-link bit
set can communicate with each other on an IPv6 link. However, the
vehicular link model needs to define the relationship between a link
and a prefix, considering the dynamics of wireless links and the
characteristics of VANET.
A VANET can have multiple links between pairs of vehicles within
wireless communication range, as shown in
. When two vehicles
belong to the same VANET, but they are out of wireless communication
range, they cannot communicate directly with each other. Suppose that
a global-scope IPv6 prefix is assigned to VANETs in vehicular networks.
Even though two vehicles in the same VANET configure their IPv6
addresses with the same IPv6 prefix, they may not communicate with each
other not in a one hop in the same VANET because of the multihop
network connectivity between them. Thus, in this case, the concept of
an on-link IPv6 prefix does not hold because two vehicles with the
same on-link IPv6 prefix cannot communicate directly with each other.
Also, when two vehicles are located in two different VANETs with the
same IPv6 prefix, they cannot communicate with each other. When these
two VANETs converge to one VANET, the two vehicles can communicate with
each other in a multihop fashion, for example, wheh they are Vehicle1
and Vehicle3, as shown in .
From the previous observation, a vehicular link model should consider
the frequent partitioning and merging of VANETs due to vehicle mobility.
Therefore, the vehicular link model needs to use an on-link prefix and
off-link prefix according to the network topology of vehicles such as
a one-hop reachable network and a multihop reachable network (or
partitioned networks). If the vehicles with the same prefix are
reachable 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 multihop
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
connected VANET where the vehicles with the same global-scope IPv6
prefix are connected in one hop or multiple hops. It also needs to
support the multihop routing in multiple connected VANETs through
infrastructure nodes (e.g., IP-RSU) where they are connected to the
infrastructure. For example, in
, suppose that
Vehicle1, Vehicle2, and Vehicle3 are configured with their IPv6
addresses based on the same global-scope IPv6 prefix. Vehicle1 and
Vehicle3 can also communicate with each other via either multihop
V2V or multihop V2I2V. When the two vehicles of Vehicle1 and
Vehicle3 are connected in a VANET, it will be more efficient for
them to directly communicate with each other via VANET rather than
indirectly via IP-RSUs. On the other hand, when the two vehicles
of Vehicle1 and Vehicle3 are far away from the communication range
in separate VANETs and under two different IP-RSUs, they can
communicate with each other through the relay of IP-RSUs via V2I2V.
Thus, two separate VANETs can merge into one network via IP-RSU(s).
Also, newly arriving vehicles can merge two separate VANETs into
one VANET if they can play a role of a relay node for those VANETs.
For the protection of drivers' privacy, a pseudonym of a MAC
address of a vehicle's network interface should be used, so that
the MAC address can be changed periodically. However, although
such a pseudonym of a MAC address can protect some extent of
privacy of a vehicle, it may not be able to resist attacks on
vehicle identification by other fingerprint information, for example,
the scrambler seed embedded in IEEE 802.11-OCB frames
. The pseudonym of a MAC address
affects an IPv6 address based on the MAC address, and a
transport-layer (e.g., TCP and and SCTP) session with an IPv6
address pair. However, the pseudonym handling is not implemented
and tested yet for applications on IP-based vehicular networking.
In the ETSI standards, for the sake of security and privacy, an
ITS station (e.g., vehicle) can use pseudonyms for its network
interface identities (e.g., MAC address) and the corresponding
IPv6 addresses . Whenever
the network interface identifier changes, the IPv6 address based
on the network interface identifier needs to be updated, and the
uniqueness of the address needs to be checked through the DAD
procedure. For vehicular networks with high mobility and density,
this DAD needs to be performed efficiently with minimum overhead
so that the vehicles can exchange application messages (e.g.,
collision avoidance and accident notification) with each other
with a short interval (e.g., 0.5 second)
.
For multihop V2V communications in either a VANET or VANETs
via IP-RSUs, 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 subnet with the same IPv6
prefix. However, it will be costly to run both vehicular ND
and a vehicular ad hoc routing protocol in terms of control
traffic overhead .
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 because the IPv6 ND is used to check the
neighborhood of each vehicle. Thus, the vehicular routing
needs to take advantage of the IPv6 ND to minimize its control
overhead.
The seamless connectivity and timely data exchange between
two end points requires an efficient mobility management
including location management and handover.
Most of vehicles are equipped with a GPS receiver as part of
a dedicated navigation system or a corresponding smartphone
App. Note that The GPS receiver may not provide vehicles with
accurate location information in adverse environments such as
a building area and tunnel. The location precision can be
improved by the assistance from the IP-RSUs or a cellular system
with a GPS receiver for location information.
With a GPS navigator, an efficient mobility management can
be performed with the help of vehicles periodically reporting
their current position and trajectory (i.e., navigation path) to
the vehicular infrastructure (having IP-RSUs and an MA in TCC).
This vehicular infrastructure can predict the future positions
of the vehicles with their mobility information (i.e., the current
position, speed, direction, and trajectory) for the efficient mobility
management (e.g., proactive handover). For a better proactive
handover, link-layer parameters, such as the signal strength of a
link-layer frame (e.g., Received Channel Power Indicator (RCPI)
), can be used to determine the
moment of a handover between IP-RSUs along with mobility
information.
By predicting a vehicle's mobility, the vehicular infrastructure
needs to better support IP-RSUs to perform efficient SLAAC, data
forwarding, horizontal handover (i.e., handover in wireless links
using a homogeneous radio technology), and vertical handover
(i.e., handover in wireless links using heterogeneous radio
technologies) in advance along with the movement of the vehicle.
For example, as shown in ,
when a vehicle (e.g., Vehicle2) is moving from the coverage of an
IP-RSU (e.g., IP-RSU1) into the coverage of another IP-RSU (e.g.,
IP-RSU2) belonging to a different subnet, the IP-RSUs can
proactively support the IPv6 mobility of the vehicle, while
performing the SLAAC, data forwarding, and handover for the sake
of the vehicle.
Therefore, for the proactive and seamless IPv6 mobility of vehicles,
the vehicular infrastructure (including IP-RSUs and MA) needs to
efficiently perform the mobility management of the vehicles with
their mobility information and link-layer information.
This section discusses security and privacy for IPv6-based vehicular
networking. The security and privacy is one of key components in
IPv6-based vehicular networking along with neighbor discovery and
mobility management.
Security and privacy are paramount in the V2I, V2V, and V2X
networking. Only authorized vehicles need to be allowed to use
the vehicular networking. Also, in-vehicle devices (e.g., ECU) and
mobile devices (e.g., smartphone) in a vehicle need to
communicate with other in-vehicle devices and mobile devices in
another vehicle, and other servers in an IP-RSU in a secure way.
Even a perfectly authorized and legitimate vehicle may be hacked
to run malicious applications to track and collect its and other
vehicles' information. For this case, an attack mitigation process
may be required to reduce the aftermath of the malicious behaviors.
Strong security measures shall protect vehicles roaming in road
networks from the attacks of malicious nodes, which are controlled
by hackers. For safety applications, the cooperation among
vehicles is assumed. Malicious nodes may disseminate wrong
driving information (e.g., location, speed, and direction) to make
driving be unsafe. For example, Sybil attack, which tries to confuse
a vehicle with multiple false identities, disturbs a vehicle in taking a
safe maneuver. This sybil attack needs to be prevented through the
cooperation between good vehicles and IP-RSUs. Note that good
vehicles are ones with valid certificates that are determined by the
authentication process with an authentication server in the vehicular
cloud. However, applications on IPv6-based vehicular networking,
which are resilient to such a sybil attack, are not developed and
tested yet.
To identify the genuineness of vehicles against malicious vehicles,
an authentication method is required.
A Vehicle Identification Number (VIN) and a user certificate along
with in-vehicle device's identifier generation can be used to
efficiently authenticate a vehicle or a user through a road
infrastructure node (e.g., IP-RSU) connected to an authentication
server in the vehicular cloud. Also, Transport Layer Security (TLS)
certificates can be used for the vehicle authentication to allow
secure E2E vehicle communications.
To identify the genuineness of vehicles against malicious vehicles,
an authentication method is required. For vehicle authentication,
information available from a vehicle or a driver (e.g., Vehicle
Identification Number (VIN) and Transport Layer Security (TLS)
certificate ) needs to be used to
efficiently authenticate a vehicle or a user with the help of a
road infrastructure node (e.g., IP-RSU) connected to an
authentication server in the vehicular cloud.
For secure V2I communication, a secure channel between a
mobile router (i.e., IP-OBU) in a vehicle and a fixed router (i.e.,
IP-RSU) in an EN needs to be established, as shown in
. Also, for secure V2V
communication, a secure channel between a mobile router (i.e.,
IP-OBU) in a vehicle and a mobile router (i.e., IP-OBU) in another
vehicle needs to be established, as shown in
.
To prevent an adversary from tracking a vehicle with its MAC
address or IPv6 address, MAC address pseudonym needs to be
provided to the vehicle; that is, each vehicle periodically updates
its MAC address and the corresponding IPv6 address
.
Such an update of the MAC and IPv6 addresses should not
interrupt the E2E communications between two vehicles (or
between a vehicle and an IP-RSU) for a long-living transport-layer
session. However, if this pseudonym is performed without strong
E2E confidentiality, there will be no privacy benefit from changing
MAC and IPv6 addresses, because an adversary can observe the
change of the MAC and IPv6 addresses and track the vehicle with
those addresses.
For the IPv6 ND, the DAD is required for the uniqueness of the
IPv6 address of a vehicle's wireless interface. This DAD can be
used as a flooding attack that makes the DAD-related ND packets
are disseminated over the VANET or vehicular networks. Thus,
the vehicles and IP-RSUs need to filter out suspicious ND traffic in
advance.
For the mobility management, a malicious vehicle can construct
multiple virtual bogus vehicles, and register them with IP-RSUs
and MA. This registration makes the IP-RSUs and MA waste their
resources. The IP-RSUs and MA need to determine whether
a vehicle is genuine or bogus in the mobility management.
Also, the confidentiality of control packets and data packets
among IP-RSUs and MA, the E2E paths (e.g., tunnels) need to be
protected by secure communication channels.
In addition, to prevent bogus IP-RSUs and MA from interfering
IPv6 mobility of vehicles, the mutual authentication among them
needs to be performed by certificates (e.g., TLS certificate).
Internet Protocol, Version 6 (IPv6) SpecificationMobility Support in IPv6Proxy Mobile IPv6Basic Support for IPv6 Networks Operating Outside the Context of
a Basic Service Set over IEEE Std 802.11Mobility Related TerminologyControl And Provisioning of Wireless Access Points
(CAPWAP) Protocol SpecificationSoftware-Defined Networking: A Perspective from within a Service Provider EnvironmentNeighbor Discovery for IP Version 6 (IPv6)IPv6 Stateless Address AutoconfigurationIP Addressing Model in Ad Hoc NetworksRandomness Requirements for SecurityPrivacy Extensions for Stateless Address Autoconfiguration in IPv6Neighbor Discovery Optimization for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs)Ad hoc On-Demand Distance Vector (AODV) RoutingThe Optimized Link State Routing Protocol Version 2IPv6 Address Prefix Reserved for DocumentationEvolution of the IP ModelThe Transport Layer Security (TLS) Protocol Version 1.3Multicast Considerations over IEEE 802 Wireless MediaStandard Specification for Telecommunications and Information Exchange Between Roadside and Vehicle Systems - 5 GHz Band Dedicated Short Range Communications (DSRC) Medium Access Control (MAC) and Physical Layer (PHY) Specifications
ASTM International
Commission Decision of 5 August 2008 on the Harmonised Use of Radio Spectrum in the 5875 - 5905 MHz Frequency Band for Safety-related Applications of Intelligent Transport Systems (ITS)
European Union
Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications - Amendment 6: Wireless Access in Vehicular EnvironmentsPart 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) SpecificationsIEEE Guide for Wireless Access in Vehicular Environments (WAVE) - ArchitectureIEEE Standard for Wireless Access in Vehicular Environments - Security Services for Applications and Management MessagesIEEE Standard for Wireless Access in Vehicular Environments (WAVE) - Networking ServicesIEEE Standard for Wireless Access in Vehicular Environments (WAVE) - Multi-Channel OperationIntelligent Transport Systems - Communications Access for Land Mobiles (CALM) - IPv6 NetworkingArchitecture Enhancements for V2X Services
3GPP
VIP-WAVE: On the Feasibility of IP Communications in 802.11p Vehicular NetworksCross-layer Identities Management in ITS StationsSAINT: Self-Adaptive Interactive Navigation Tool for Cloud-Based Vehicular Traffic OptimizationSAINT+: Self-Adaptive Interactive Navigation Tool+ for Emergency Service Delivery OptimizationSANA: Safety-Aware Navigation Application for Pedestrian Protection in Vehicular NetworksCASD: A Framework of Context-Awareness Safety Driving in Vehicular NetworksCooperative Adaptive Cruise ControlAutomated Truck PlatooningFirst Responder Network Authority (FirstNet)FY 2017: ANNUAL REPORT TO CONGRESS, Advancing Public Safety
Broadband Communications
First Responder Network Authority
Fuel-Efficient En Route Formation of Truck PlatoonsMillimeter-Wave Vehicular Communication to Support Massive Automotive SensingFinal Report of Automotive Collision Avoidance Systems (ACAS) Program
National Highway Traffic Safety Administration (NHTSA)
The Scrambler Attack: A Robust Physical Layer Attack on Location Privacy in Vehicular NetworksDefeating MAC Address Randomization Through Timing Attacks The following changes are made from draft-ietf-ipwave-vehicular-networking-12:
This version is revised based on the comments from Carlos Bernardos.
This version focuses on problems rather than solutions for IPWAVE.
Also, this version addresses the requirements of IPv6 neighbor
discovery, mobility management, and security and privacy.
In , IP-OBU and IP-RSU are
used instead of OBU and RSU, respectively.
In , an
exemplary vehicular network architecture is illustrated for the problem
statement as .
This work was supported by Basic Science Research Program through the
National Research Foundation of Korea (NRF) funded by the Ministry of
Education (2017R1D1A1B03035885).
This work was supported in part by the MSIT (Ministry of Science and ICT), Korea,
under the ITRC (Information Technology Research Center) support program
(IITP-2019-2017-0-01633) supervised by the IITP (Institute for Information &
communications Technology Promotion).
This work was supported in part by the French research project DataTweet
(ANR-13-INFR-0008) and in part by the HIGHTS project funded by the
European Commission I (636537-H2020).
This document is a group work of IPWAVE working group, greatly benefiting
from inputs and texts by Rex Buddenberg (Naval Postgraduate School),
Thierry Ernst (YoGoKo), Bokor Laszlo (Budapest University of Technology
and Economics), Jose Santa Lozanoi (Universidad of Murcia), Richard Roy (MIT),
Francois Simon (Pilot), Sri Gundavelli (Cisco), Erik Nordmark, Dirk von Hugo
(Deutsche Telekom), Pascal Thubert (Cisco), Carlos Bernardos (UC3M),
Russ Housley (Vigil Security), and Suresh Krishnan (Kaloom).
The authors sincerely appreciate their contributions.
The following are co-authors of this document:
Nabil Benamar
Department of Computer Sciences
High School of Technology of Meknes
Moulay Ismail University
Morocco
Phone: +212 6 70 83 22 36
EMail: benamar73@gmail.com
Sandra Cespedes
NIC Chile Research Labs
Universidad de Chile
Av. Blanco Encalada 1975
Santiago
Chile
Phone: +56 2 29784093
EMail: scespede@niclabs.cl
Jerome Haerri
Communication Systems Department
EURECOM
Sophia-Antipolis
France
Phone: +33 4 93 00 81 34
EMail: jerome.haerri@eurecom.fr
Dapeng Liu
Alibaba
Beijing, Beijing 100022
China
Phone: +86 13911788933
EMail: max.ldp@alibaba-inc.com
Tae (Tom) Oh
Department of Information Sciences and Technologies
Rochester Institute of Technology
One Lomb Memorial Drive
Rochester, NY 14623-5603
USA
Phone: +1 585 475 7642
EMail: Tom.Oh@rit.edu
Charles E. Perkins
Futurewei Inc.
2330 Central Expressway
Santa Clara, CA 95050
USA
Phone: +1 408 330 4586
EMail: charliep@computer.org
Alexandre Petrescu
CEA, LIST
CEA Saclay
Gif-sur-Yvette, Ile-de-France 91190
France
Phone: +33169089223
EMail: Alexandre.Petrescu@cea.fr
Yiwen Chris Shen
Department of Computer Science & Engineering
Sungkyunkwan University
2066 Seobu-Ro, Jangan-Gu
Suwon, Gyeonggi-Do 16419
Republic of Korea
Phone: +82 31 299 4106
Fax: +82 31 290 7996
EMail: chrisshen@skku.edu
URI: http://iotlab.skku.edu/people-chris-shen.php
Michelle Wetterwald
FBConsulting
21, Route de Luxembourg
Wasserbillig, Luxembourg L-6633
Luxembourg
EMail: Michelle.Wetterwald@gmail.com