IP Wireless Access in Vehicular Environments (IPWAVE): Problem Statement and Use Cases
Department of Software
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 on
IP-based vehicular networks, which are considered a key component of
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 surveys use cases using V2V, V2I, and V2X networking. Second, it
analyzes proposed protocols for IP-based vehicular networking and
highlights the limitations and difficulties found on those protocols.
Third, it presents a problem exploration for key aspects in
IP-based vehicular networking, such as IPv6 Neighbor Discovery,
Mobility Management, and Security & Privacy. For each key aspect,
this document discusses a problem statement to evaluate the gap between
the state-of-the-art techniques and requirements in IP-based vehicular
networking.
Vehicular networking studies have mainly focused on driving safety,
driving efficiency, and entertainment in road networks. The Federal
Communications Commission (FCC) in the US allocated wireless channels
for Dedicated Short-Range Communications (DSRC) , service in the
Intelligent Transportation Systems (ITS) Radio Service in the
5.850 - 5.925 GHz band (5.9 GHz band). DSRC-based wireless communications
can support vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I),
and vehicle-to-everything (V2X) networking.
Also, the European Union (EU) passed a decision to allocate radio spectrum for safety-related and non-safety-related applications of ITS with the frequency band of 5.875 - 5.905 GHz, which
is called 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 the DSRC in
terms of standards for the Wireless Access in Vehicular Environments (WAVE)
system. L1 and 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.
Note that IEEE 802.11p has been published as IEEE 802.11 Outside the Context
of a Basic Service Set (OCB) called IEEE 802.11-OCB
in 2012.
Along with these WAVE standards,
IPv6 and Mobile IP protocols
(e.g., MIPv4 and MIPv6 )
can be applied (or easily modified) to vehicular networks.
In Europe, ETSI has standardized a GeoNetworking (GN) protocol
and a protocol adaptation sub-layer from GeoNetworking to
IPv6 . Note that a GN protocol is useful to route an event or notification message to vehicles around a geographic position, such as an acciendent 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 Mobiles (CALM) .
This document discusses problem statements and use cases related to
IP-based vehicular networking for Intelligent Transportation Systems
(ITS), which is denoted as IP Wireless Access in Vehicular Environments (IPWAVE).
First, it surveys the use cases for using V2V, V2I, and V2X networking
in the ITS.
Second, for literature review, it analyzes proposed protocols for
IP-based vehicular networking and highlights the limitations and
difficulties found on those protocols.
Third, for problem statement, it presents a problem exploration with
key aspects in IPWAVE, such as IPv6 Neighbor Discovery, Mobility
Management, and Security & Privacy. For each key aspect of the
problem statement, it analyzes the gap between the
state-of-the-art techniques and the requirements in IP-based vehicular
networking. It also discusses potential topics relevant to
IPWAVE Working Group (WG), such as Vehicle Identities Management, Multihop V2X Communications,
Multicast, DNS Naming Services, Service Discovery, and IPv6 over Cellular
Networks.
Therefore, with the problem statement, this document will open a door to
develop key protocols for IPWAVE that will be essential to IP-based
vehicular networks.
This document uses the following definitions:
WAVE: Acronym for "Wireless Access in Vehicular Environments"
.
DMM: Acronym for "Distributed Mobility Management" .
Road-Side Unit (RSU): A node that has physical communication devices
(e.g., DSRC, Visible Light Communication, 802.15.4, LTE-V2X, etc.)
for wireless communications with
vehicles and is also connected to the Internet as a router or
switch for packet forwarding. An RSU is typically deployed on the
road infrastructure, either at an intersection or in a road segment,
but may also be located in car parking area.
On-Board Unit (OBU): A node that has a DSRC device for wireless
communications with other OBUs and RSUs, and may be connected to
in-vehicle devices or networks. An OBU is mounted on a
vehicle. It is assumed that a radio navigation receiver (e.g.,
Global Positioning System (GPS)) is included in a vehicle with
an OBU for efficient navigation.
Vehicle Detection Loop (or Loop Detector): An inductive device
used for detecting vehicles passing or arriving at a certain point,
for instance approaching a traffic light or in motorway traffic.
The relatively crude nature of the loop's structure means that only
metal masses above a certain size are capable of triggering the detection.
Mobility Anchor (MA): A node that maintains IP addresses and
mobility information of vehicles in a road network to support
the address autoconfiguration and mobility management of them.
It has end-to-end connections with RSUs under its control.
It maintains a DAD table having the IP addresses of the vehicles
moving within the communication coverage of its RSUs.
Vehicular Cloud: A cloud infrastructure for vehicular networks, having
compute nodes, storage nodes, and network nodes.
Traffic Control Center (TCC): A node that maintains road
infrastructure information (e.g., 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.
This section provides use cases of V2V, V2I, and V2X networking. The use cases of the V2X networking exclude the ones of the V2V and V2I networking, but include Vehicle-to-Pedestrian (V2P) and Vehicle-to-Device (V2D).
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 letting the drivers recognize
dangerous obstacles and situations. That is, CASD navigator displays
obstables 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, such as the Line-of-Sight unsafe, Non-Line-of-Sight
unsafe and safe situations. This action plan can be performed among
vehicles through 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. CACC can help adjacent vehicles to
efficiently adjust their speed in a cascade way through V2V networking.
Platooning allows a series of
vehicles (e.g., trucks) to move together with a very short
inter-distance. 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).
This 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. Data generated by those sensors can be substantially large, and these data shall be routed to different destinations. In addition, from the perspective of driverless vehicles, it is expected that driverless vehicles can be mixed with driver-operated vehicles. Through cooperative environment sensing, driver-operated vehicles can use environmental information sensed by driverless vehicles for better interaction with the context.
The use cases of V2I networking discussed in this section include
Navigation service;Energy-efficient speed recommendation service;Accident notification service.
A navigation service, such as the Self-Adaptive Interactive Navigation Tool
(called 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 SAINT (called SAINT+) can
give the fast moving paths for emergency vehicles (e.g., ambulance
and fire engine) toward accident spots while providing other vehicles
with efficient detour paths.
A TCC can recommend an energy-efficient speed to a vehicle driving in different traffic environments. 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 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, such as
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 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.
The use case of V2X networking discussed in this section is pedestrian protection service.
A pedestrian protection service, such as Safety-Aware Navigation Application (called SANA) , using V2I2P networking can reduce the collision of a vehicle and a pedestrian carrying a smartphone equipped with the access technology with an RSU (e.g., WiFi). Vehicles and pedestrians can also communicate with each other via an RSU that delivers scheduling information for wireless communication in order to save the smartphones' battery through sleeping mode.
For Vehicle-to-Pedestrian (V2P), a vehicle and a pedestrian's smartphone can directly communicate with each other via V2X without the relaying of an RSU as in a V2V scenario such that the pedestrian's smartphone is regarded as a vehicle with a wireless media interface to be able to communicate with another vehicle. In Vehicle-to-Device (V2D), a device can be a mobile node such as bicycle and motorcycle, and can communicate directly with a vehicle for collision avoidance.
We describe some currently existing protocols and proposed solutions
with respect to the following aspects that are relevant and
essential for vehicular networking:
IPv6 over 802.11-OCB;
IP address autoconfiguration;
Routing;
Mobility management;
DNS naming service;
Service discovery;
Security and privacy.
For IPv6 packets transporting over IEEE 802.11-OCB,
specifies several details, such as
Maximum Transmission Unit (MTU), frame format, link-local address,
address mapping for unicast and multicast, stateless autoconfiguration, and
subnet structure. Especially, an Ethernet Adaptation (EA)
layer is in charge of transforming some parameters between IEEE 802.11 MAC layer
and IPv6 network layer, which is located between IEEE 802.11-OCB's logical link
control layer and IPv6 network layer.
For IP address autoconfiguration, Fazio et al. proposed a vehicular address configuration (VAC) scheme using DHCP where elected leader-vehicles provide unique identifiers for IP address configurations in vehicles . Kato et al. proposed an IPv6 address assignment scheme using lane and position information . Baldessari et al. proposed an IPv6 scalable address autoconfiguration scheme called GeoSAC for vehicular networks . Wetterwald et al. conducted for heterogeneous vehicular networks (i.e., employing multiple access technologies) a comprehensive study of the cross-layer identities management, which constitutes a fundamental element of the ITS architecture .
For routing, Tsukada et al. presented a work that aims at combining IPv6 networking and a Car-to-Car Network routing protocol (called C2CNet) proposed by the Car2Car Communication Consortium (C2C-CC), which is an architecture using a geographic routing protocol . Abrougui et al. presented a gateway discovery scheme for VANET, called Location-Aided Gateway Advertisement and Discovery (LAGAD) mechanism .
For mobility management, Chen et al. tackled the issue of network fragmentation in VANET environments by proposing a protocol that can postpone the time to release IP addresses to the DHCP server and select a faster way to get the vehicle's new IP address, when the vehicle density is low or the speeds of vehicles are highly variable. Nguyen et al. proposed a hybrid centralized-distributed mobility management called H-DMM to support highly mobile vehicles . proposed an architecture to enable IP mobility for moving networks using a network-based mobility scheme based on PMIPv6. Chen et al. proposed a network mobility protocol to reduce handoff delay and maintain Internet connectivity to moving vehicles in a highway . Lee et al. proposed P-NEMO, which is a PMIPv6-based IP mobility management scheme to maintain the Internet connectivity at the vehicle as a mobile network, and provides a make-before-break mechanism when vehicles switch to a new access network . Peng et al. proposed a novel mobility management scheme for integration of VANET and fixed IP networks . Nguyen et al. extended their previous works on a vehicular adapted DMM considering a Software-Defined Networking (SDN) architecture .
For DNS naming service, Multicast DNS (mDNS) allows devices in one-hop communication range to resolve each other's DNS name into the corresponding IP address in multicast. DNS Name Autoconfiguration (DNSNA) proposes a DNS naming service for Internet-of-Things (IoT) devices in a large-scale network.
To discover instances of a demanded service in vehicular networks, DNS-based Service Discovery (DNS-SD) with either DNSNA or mDNS provides vehicles with service discovery by using standard DNS queries. Vehicular ND proposes an extension of IPv6 ND for the prefix and service discovery with new ND options . Note that a DNS query for service discovery is unicasted in DNSNA, but it is multicasted in both mDNS and Vehicular ND.
For security and privacy, Fernandez et al. proposed a secure vehicular IPv6 communication scheme using Internet Key Exchange version 2 (IKEv2) and Internet Protocol Security (IPsec) . Moustafa et al. proposed a security scheme providing authentication, authorization, and accounting (AAA) services in vehicular networks .
This section describes a possible vehicular network architecture for V2V, V2I, and V2X communications.
Then it analyzes the limitations of the current protocols for vehicular networking.
shows a possible
architecture for V2I and V2V networking in a road network.
It is assumed that RSUs as routers and vehicles with OBU have wireless
media interfaces (e.g., IEEE 802.11-OCB, LTE Uu and Device-to-Device (D2D)
(also known as PC5 ),
Bluetooth, and Light Fidelity (Li-Fi)) for V2I and V2V communication.
Also, it is assumed that such 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.
Three RSUs (RSU1, RSU2, and RSU3) are deployed in the road network
and are connected to a Vehicular Cloud through the Internet.
A Traffic Control Center (TCC) is connected to the 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 component for
the mobility management of vehicles. Two vehicles (Vehicle1 and Vehicle2)
are wirelessly connected to RSU1, and one vehicle (Vehicle3)
is wirelessly connected to RSU2. The wireless networks of RSU1 and RSU2
belong to a multi-link subnet (denoted as Subnet1) with the same network prefix.
Thus, these three vehicles are within the same subnet.
On the other hand, another vehicle (Vehicle4) is wireless connected to RSU4,
belonging to another subnet (denoted as Subnet2). That is, the first three
vehicles (i.e., Vehicle1, Vehicle2, and Vehicle3) and the last vehicle
(i.e., Vehicle4) are located in the two different subnets.
Vehicle1 can communicate with Vehicle2 via V2V communication, and
Vehicle2 can communicate with Vehicle3 via V2V communication because
they are within the same subnet along their IPv6 addresses, which are
based on the same prefix. On the other hand, Vehicle3 can communicate with
Vehicle4 via RSU2 and RSU3 employing V2I (i.e., V2I2V) communication
because they are within the two different subnets along with their IPv6
addresses, which are based on the two different prefixes.
In vehicular networks, unidirectional links exist and must be
considered for wireless communications. Also, in the vehicular networks,
control plane must be separated from data plane for efficient mobility
management and data forwarding using Software-Defined Networking (SDN)
.
ID/Pseudonym change for privacy requires a lightweight DAD.
IP tunneling over the wireless link should be avoided for performance efficiency.
The mobility information of a mobile (e.g., vehicle-mounted) device
through a GPS receiver in its vehicle, such as trajectory, position, speed,
and direction, can be used by the mobile device and infrastructure nodes
(e.g., TCC and RSU) for the accommodation of mobility-aware proactive protocols.
Vehicles can use the TCC as their Home Network having a home agent for mobility
management as in MIPv6 and Proxy Mobile IPv6 (PMIPv6) ,
so the TCC maintains the mobility information of vehicles for location management.
Cespedes et al. proposed a vehicular IP in WAVE called VIP-WAVE for
I2V and V2I networking .
The standard WAVE does not support both seamless communications for
Internet services and multi-hop communications between a vehicle and
an infrastructure node (e.g., RSU), either. To overcome these limitations
of the standard WAVE, VIP-WAVE enhances the standard WAVE by the
following three schemes: (i) an efficient mechanism for the IPv6
address assignment and DAD, (ii) on-demand IP mobility based on PMIPv6
, and (iii) one-hop and two-hop communications
for I2V and V2I networking.
Baccelli et al. provided an analysis of the operation of IPv6 as it
has been described by the IEEE WAVE standards 1609
. This analysis confirms that the use of
the standard IPv6 protocol stack in WAVE is not sufficient. It recommends that
the IPv6 addressing assignment should follow considerations for ad-hoc link
models, defined in for nodes' mobility and link
variability.
Petrescu et al. proposed the joint IP networking and radio architecture
for V2V and V2I communication in .
The proposed architecture considers an IP topology in a similar way as
a radio link topology, in the sense that an IP subnet would correspond
to the range of 1-hop vehicular communication. This architecture defines
three types of vehicles: Leaf Vehicle, Range Extending Vehicle, and
Internet Vehicle.
This section discusses the internetworking between a vehicle's
moving network and an RSU's fixed network via V2I communication.
As shown in , the
vehicle's moving network and the RSU's fixed network are self-contained networks having multiple subnets and having an edge router for the communication with another vehicle or RSU. The method of prefix assignment for each subnet inside the vehicle's mobile network and the RSU's fixed network is out of scope for this document. Internetworking between two internal networks via V2I communication requires an exchange of network prefix and other parameters through a prefix discovery mechanism, such as ND-based prefix discovery . For the ND-based prefix discovery, network prefixs and parameters should be registered into a vehicle's router and an RSU router with an external network interface in advance.
The network parameter discovery collects networking information
for an IP communication between a vehicle and an RSU or between two
neighboring vehicles, such as link layer, MAC layer, and IP layer
information. The link layer information includes wireless link layer
parameters, such as wireless media (e.g., IEEE 802.11-OCB, LTE Uu and D2D,
Bluetooth, and LiFi) and a transmission power level.
Note that LiFi is a technology for light-based wireless communication
between devices in order to transmit both data and position.
The MAC layer information includes the MAC address of an external
network interface for the internetworking with another vehicle or RSU.
The IP layer information includes the IP address and prefix of an
external network interface for the internetworking with another
vehicle or RSU.
Once the network parameter discovery and prefix exchange operations have been performed, packets can be transmitted between the vehicle's moving network and the RSU's fixed network. DNS services should be supported to enable name resolution for hosts or servers residing either in the vehicle's moving network or the RSU's fixed network. It is assumed that the DNS names of in-vehicle devices and their service names are registered into a DNS server (i.e., recursive DNS server called RDNSS) in a vehicle or an RSU, as shown in . For service discovery, those DNS names and service names can be advertised to neighboring vehicles through either DNS-based service discovery mechanisms and ND-based service discovery . For the ND-based service discovery, service names should be registered into a vehicle's router and an RSU router with an external network interface in advance.
Refer to and for detailed information.
For these DNS services, an RDNSS within each internal network of a vehicle or RSU can be used for the hosts or servers.
shows internetworking
between the vehicle's moving network and the RSU's fixed network.
There exists an internal network (Moving Network1) inside Vehicle1.
Vehicle1 has the DNS Server (RDNSS1), the two hosts (Host1 and Host2),
and the two routers (Router1 and Router2). There exists another
internal network (Fixed Network1) inside RSU1. RSU1 has the DNS Server
(RDNSS2), one host (Host3), the two routers (Router3 and Router4),
and the collection of servers (Server1 to ServerN) for various services
in the road networks, such as the emergency notification and
navigation. Vehicle1's Router1 (called mobile router) and RSU1's
Router3 (called fixed router) use 2001:DB8:1:1::/64 for an external
link (e.g., DSRC) for I2V networking.
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 the DNS Server (RDNSS1), the two hosts (Host1 and Host2),
and the two routers (Router1 and Router2). There exists another
internal network (Moving Network2) inside Vehicle2. Vehicle2 has
the DNS Server (RDNSS3), the two hosts (Host4 and Host5), and the
two routers (Router5 and Router6). Vehicle1's Router1 (called mobile
router) and Vehicle2's Router5 (called mobile router) use
2001:DB8:1:1::/64 for an external link (e.g., DSRC) for V2V networking.
The differences between IPWAVE (including Vehicular Ad Hoc Networks (VANET))
and Mobile Ad Hoc Networks (MANET) are as follows:
IPWAVE is not power-constrained operation;
Traffic can be sourced or sinked outside of IPWAVE;
IPWAVE shall support both distributed and centralized operations;
No "sleep" period operation is required for energy saving.
The communication delay (i.e., latency) between two vehicular nodes (vehicle and RSU)
should be bounded to a certain threshold. For IP-based safety applications
(e.g., context-aware navigation, adaptive cruise control, and platooning) in
vehicular network, this bounded data delivery is critical. The real implementations
for such applications are not available, so the feasibility of IP-based safety
applications is not tested yet.
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.
Sybil attack, which tries to illude a vehicle with multiple false identities,
disturbs a vehicle in taking a safe maneuver.
Applications on IP-based vehicular networking, which are resilient to such
a sybil attack, are not developed and tested yet.
For the protection of drivers' privacy, pseudonym for a vehicle's network interface should be used, with the help of which the interface's identifier can be changed periodically.
Such a pseudonym affects an IPv6 address based on the network interface's identifier,
and a transport-layer (e.g., TCP) session with an IPv6 address pair. The pseudonym
handling is not implemented and tested yet for applications on IP-based vehicular
networking.
This section discusses key topics for IPWAVE WG, such as neighbor discovery,
mobility management, and security & privacy.
Neighbor Discovery (ND) is a core part of
the IPv6 protocol suite. This section discusses the need for modifying
ND for use with vehicular networking (e.g., V2V, V2I, and V2X).
The vehicles are moving fast within the communication coverage of a vehicular
node (e.g., vehicle and RSU). The external wireless link between two vehicular nodes
can be used for vehicular networking, as shown in
and .
ND time-related parameters such as router lifetime and Neighbor
Advertisement (NA) interval should be adjusted for high-speed
vehicles and vehicle density. As vehicles move faster, the NA
interval should decrease for the NA messages to reach the neighboring
vehicles promptly. Also, as vehicle density is higher, the NA
interval should increase for the NA messages to reduce collision
probability with other NA messages.
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, interference and different levels of transmission power may
cause unidirectional links to appear in vehicular wireless links.
As a result, a new vehicular link model is required for the vehicular
wireless link.
There is a relationship between a link and 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 IP link or extended IP links via ND proxy.
Note that a subnet prefix can be used by spanning multiple links
as a multi-link subnet . Also, note that
IPv6 Stateless Address Autoconfiguration can be performed in the multiple
links where each of them is not assigned with a unique subnet prefix, that is,
all of them are configured with the same subnet prefix
.
A vehicular link model needs to consider a multi-hop VANET over a multi-link subnet.
Such a VANET is usually a multi-link subnet consisting of multiple vehicles
interconnected by wireless communication range. Such a subnet has a highly
dynamic topology over time due to node mobility.
Thus, IPv6 ND should be extended into a Vehicular Neighbor Discovey (VND)
to support the concept of an IPv6 link
corresponding to an IPv6 prefix even in a multi-link subnet consisting of
multiple vehicles and RSUs that are interconnected with wireless communication
range in IP-based vehicular networks.
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 should be
updated. 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., MIPv6 and PMIPv6), the new IP
address for the transport-layer session should be notified to an appropriate end point,
and the packets of the session should be forwarded to their destinations with
the changed network interface identifier and IPv6 address.
A vehicle and an RSU can have their internal network, as shown in
and
. In this case, nodes in
within the internal networks of two vehicular nodes (e.g., vehicle and RSU)
want to communicate with each other. For this communication on the wireless link,
the network prefix dissemination or exchange is required.
It is assumed that a vehicular node has an external network interface and
its internal network. The legacy IPv6 ND needs
to be extended to a vehicular ND (VND) for
the communication between the internal-network nodes (e.g., an in-vehicle device
in a vehicle and a server in an RSU) of vehicular nodes by letting each of them
know the other side's prefix with a new ND option .
Thus, this ND extension for routing functionality can reduce control traffic
for routing in vehicular networks without an additional vehicular ad hoc routing
protocol .
For multihop V2V communications in a multi-link subnet (as a connected VANET),
a vehicular ad hoc routing protocol (e.g., geographic routing) may be required to
support both unicast and multicast in the links of the subnet with the same
IPv6 prefix .
Instead of the vehicular ad hoc routing protocol, Vehicular ND along with
a prefix discovery option can be used to let vehicles exchange their prefixes
in a multihop fashion .
With the exchanged prefixes, they can compute their routing table
(or IPv6 ND's neighbor cache) for the multi-link subnet with a distance-vector
algorithm .
Also, an efficient, rapid DAD should be supported to prevent or reduce IPv6 address
conflicts in the multi-link subnet by using a DAD optimization
or an IPv6 geographic-routing-based address autoconfiguration
.
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.
In the case where the provided location information is precise enough,
well-known temporary degradations in precision may occur due to system
configuration or the adverse local environment. This precision is improved
thanks to assistance by the RSUs or a cellular system with this navigation system.
With this GPS navigator, an efficient mobility management is possible by
vehicles periodically reporting their current position and trajectory
(i.e., navigation path) to RSUs and a Mobility Anchor (MA) in TCC. The RSUs and MA
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 RSUs along with mobility information .
With the prediction of the vehicle mobility, MA can support RSUs to perform DAD,
data packet routing, 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 a proactive manner.
Even though a vehicle moves into the wireless link under another RSU belonging to
a different subnet, the RSU can proactively perform the DAD for the sake of
the vehicle, reducing IPv6 control traffic overhead in the wireless link
.
Therefore, with a proactive handover and a multihop DAD in vehicular networks
, RSUs can efficiently forward data packets
from the wired network (or the wireless network) to a moving destination vehicle
along its trajectory along with the MA.
Thus, a moving vehicle can communicate with its corresponding vehicle in
the vehicular network or a host/server in the Internet along its trajectory.
Security and privacy are paramount in the V2I, V2V, and V2X networking in
vehicular networks. Only authorized vehicles should be allowed to use
vehicular networking. Also, in-vehicle devices and mobile devices
in a vehicle need to communicate with other in-vehicle devices and
mobile devices in another vehicle, and other servers in an RSU in
a secure way.
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., RSU) connected to an authentication server in TCC. Also,
Transport Layer Security (TLS) certificates can be used for secure
E2E vehicle communications.
For secure V2I communication, a secure channel between a mobile
router in a vehicle and a fixed router in an RSU should be
established, as shown in .
Also, for secure V2V communication, a secure channel between a
mobile router in a vehicle and a mobile router in another vehicle
should be established, as shown in
.
To prevent an adversary from tracking a vehicle with its MAC address
or IPv6 address, MAC address pseudonym should be provided to the vehicle;
that is, each vehicle should periodically update its MAC address and the
corresponding IPv6 address as suggested in
. Such an update
of the MAC and IPv6 addresses should not interrupt the E2E
communications between two vehicular nodes (e.g., vehicle and RSU)
in terms of transport layer for a long-living higher-layer session.
However, if this pseudonym is performed without strong E2E
confidentiality, there will be no privacy benefit from changing
MAC and IP addresses, because an adversary can see the change of
the MAC and IP addresses and track the vehicle with those addresses.
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.
Internet Protocol, Version 6 (IPv6) SpecificationIP Mobility Support in IPv4, RevisedMobility Support in IPv6Proxy Mobile IPv6Requirements for Distributed Mobility ManagementDistributed Mobility Management: Current Practices and Gap AnalysisMulticast DNSDNS-Based Service DiscoveryNeighbor 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)DNS Name Autoconfiguration for Internet of Things DevicesIPv6 Neighbor Discovery for IP-Based Vehicular NetworksIPv6 Neighbor Discovery for Prefix and Service Discovery in Vehicular NetworksMulticast Considerations over IEEE 802 Wireless MediaTransmission of IPv6 Packets over IEEE 802.11 Networks operating in mode Outside the Context of a Basic Service Set (IPv6-over-80211-OCB)Standard Specification for Telecommunications and Information Exchange Between Roadside and Vehicle Systems - 5 GHz Band Dedicated Short Range Communications (DSRC) Medium Access Control (MAC) and Physical Layer (PHY) Specifications
ASTM 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 (ITS); Vehicular Communications; GeoNetworking; Part 4: Geographical addressing and forwarding for point-to-point and point-to-multipoint communications; Sub-part 1: Media-Independent FunctionalityIntelligent Transport Systems (ITS); Vehicular Communications; GeoNetworking; Part 6: Internet Integration; Sub-part 1: Transmission of IPv6 Packets over GeoNetworking ProtocolsIntelligent Transport Systems - Communications Access for Land Mobiles (CALM) - IPv6 NetworkingArchitecture Enhancements for V2X Services
3GPP
Study on Enhancement of 3GPP Support for 5G V2X Services
3GPP
Automatic IP Address Configuration in VANETsRouting and Address Assignment using Lane/Position Information in a Vehicular Ad-hoc NetworkGeoSAC - Scalable Address Autoconfiguration for VANET Using Geographic Networking ConceptsCross-layer Identities Management in ITS StationsVIP-WAVE: On the Feasibility of IP Communications in 802.11p Vehicular NetworksIPv6 Operation for WAVE - Wireless Access in Vehicular EnvironmentsJoint IP Networking and Radio Architecture for Vehicular NetworksAn IP Passing Protocol for Vehicular Ad Hoc Networks with Network FragmentationExperimental Evaluation for IPv6 over VANET Geographic RoutingLocation-Aided Gateway Advertisement and Discovery Protocol for VANetsA Hybrid Centralized-Distributed Mobility Management for Supporting Highly Mobile UsersNEMO-Enabled Localized Mobility Support for Internet Access in Automotive ScenariosNetwork Mobility Protocol for Vehicular Ad Hoc NetworksPerformance Analysis of PMIPv6-Based Network Mobility for Intelligent Transportation SystemsA Novel Mobility Management Scheme for Integration of Vehicular Ad Hoc Networks and Fixed IP NetworksSDN-based Distributed Mobility Management for 5G NetworksSecuring Vehicular IPv6 CommunicationsProviding Authentication and Access Control in Vehicular Network EnvironmentSAINT: 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 PlatoonsMulticast and Virtual Road Side Units for Multi Technology Alert Messages DisseminationMultihop-Cluster-Based IEEE 802.11p and LTE Hybrid Architecture for VANET Safety Message DisseminationMillimeter-Wave Vehicular Communication to Support Massive Automotive SensingBroadcast Storm Mitigation Techniques in Vehicular Ad Hoc NetworksIntroduction to Algorithms, 3rd ed. This section discusses topics relevant to IPWAVE WG: (i) vehicle identity
management; (ii) multihop V2X; (iii) multicast; (iv) DNS naming services
and service discovery; (v) IPv6 over cellular networks.
A vehicle can have multiple network interfaces using different access network
technologies .
These multiple network interfaces mean multiple identities.
To identify a vehicle with multiple indenties, a Vehicle Identification
Number (VIN) can be used as a globally unique vehicle identifier.
To support the seamless connectivity over the multiple identities,
a cross-layer network architecture is required with vertical handover
functionality .
Also, an AAA service for multiple identities should be provided to vehicles
in an efficient way to allow horizontal handover as well as vertical
handover; note that AAA stands for Authentication, Authorization, and
Accounting.
Multihop packet forwarding among vehicles in 802.11-OCB mode shows an
unfavorable performance due to the common known broadcast-storm problem
. This broadcast-storm problem can be
mitigated by the coordination (or scheduling) of a cluster head in
a connected VANET or an RSU in an intersection area, where the
cluster head can work as a coodinator for the access to wireless channels.
IP multicast in vehicular network environments is especially useful for various services. For instance, an automobile manufacturer can multicast a particular group/class/type of vehicles for service notification. As another example, a vehicle or an RSU can disseminate
alert messages in a particular area .
In general IEEE 802 wireless media, some performance issues about multicast are found in . Since several procedures and functions based on IPv6 use multicast for control-plane messages, such as Neighbor Discovery (ND) and Service Discovery, describes that the ND process may fail due to unreliable wireless link, causing failure of the DAD process. Also, the Router Advertisement messages can be lost in multicasting.
When two vehicular nodes communicate with each other using the DNS name of
the partner node, DNS naming service (i.e., DNS name resolution) is required.
As shown in and
, a recursive DNS server (RDNSS)
within an internal network can
perform such DNS name resolution for the sake of other vehicular nodes.
A service discovery service is required for an application in a vehicular
node to search for another application or server in another vehicular node,
which resides in either the same internal network or the other internal network.
In V2I or V2V networking, as shown in
and , such a service discovery service
can be provided by either DNS-based Service Discovery (DNS-SD)
with mDNS or
the vehicular ND with a new option for service discovery
.
Recently, 3GPP has announced a set of new technical specifications, such as Release 14 (3GPP-R14), which proposes an architecture enhancements for V2X services using the modified sidelink interface that originally is designed for the LTE-D2D communications. 3GPP-R14 specifies that the V2X services only support IPv6 implementation. 3GPP is also investigating and discussing the evolved V2X services in the next generation cellular networks, i.e., 5G new radio (5G-NR), for advanced V2X communications and automated vehicles' applications.
Before 3GPP-R14, some researchers have studied the potential usage of C-V2X communications. For example, explores a multihop cluster-based hybrid architecture using both DSRC and LTE for safety message dissemination. Most of the research considers a short message service for safety instead of IP datagram forwarding. In other C-V2X research, the standard IPv6 is assumed.
The 3GPP technical specification states that both IP based and non-IP based V2X messages are supported, and only IPv6 is supported for IP based messages. Moreover, instructs that a UE autoconfigures a link-local IPv6 address by following , but without sending Neighbor Solicitation and Neighbor Advertisement messages for DAD. This is because a unique prefix is allocated to each node by the 3GPP network, so the IPv6 addresses cannot be duplicate.
The emerging services, functions, and applications, which are developped in automotive industry, demand reliable and efficient communication infrastructure for road networks. Correspondingly, the support of enhanced V2X (eV2X)-based services by future converged and interoperable 5G systems is required. The 3GPP Technical Report is studying new use cases and the corresponding service requirements for V2X (including V2V and V2I) using 5G in both infrastructure mode and the sidelink variations in the future.
The following changes are made from draft-ietf-ipwave-vehicular-networking-06:
In , a vehicular network
architecture is modified to show a vehicular link model in a multi-link
subnet with vehicular wireless links.
In , a Vehicular Neighbor
Discovery (VND) is introduced along with
a vehicular link model in a multi-link subnet. In such a subnet,
the description of MAC Address Pseudonym, Prefix Dissemination/Exchange,
and Routing is clarified.
In , a proactive handover is
introduced for an efficient mobility management with the cooperation among
vehicles, RSUs, and MA along with link-layer parameters, such as Received
Channel Power Indicator (RCPI).
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 Global Research Laboratory Program
through the NRF funded by the Ministry of Science and
ICT (MSIT) (NRF-2013K1A1A2A02078326) and by the DGIST R&D Program
of the MSIT (18-EE-01).
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, and Dirk von Hugo (Deutsche Telekom). 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