Vehicular Mobility Management for IP-Based Vehicular Networks
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
Department of Electrical and Computer Engineering
Sungkyunkwan University2066 Seobu-Ro, Jangan-GuSuwonGyeonggi-Do16419Republic of Korea+82 10 5964 8794+82 31 290 7996bienaime@skku.edu
Department of Electrical and Computer Engineering
Sungkyunkwan University2066 Seobu-Ro, Jangan-GuSuwonGyeonggi-Do16419Republic of Korea+82 31 299 4106+82 31 290 7996chrisshen@skku.edu
Department of Computer Science and Engineering
Sungkyunkwan University2066 Seobu-Ro, Jangan-GuSuwonGyeonggi-Do16419Republic of Korea+82 31 299 4106+82 31 290 7996hyeonah214@skku.edu
Internet
IPWAVE Working GroupInternet-Draft
This document specifies a Vehicular Mobility Management (VMM) scheme for
IP-based vehicular networks. The VMM scheme takes advantage of a vehicular
link model based on a multi-link subnet. With a vehicle's mobility
information (e.g., position, speed, acceleration/deceleration, and direction)
and navigation path (i.e., trajectory), it can provide a moving vehicle with
proactive and seamless handoff along with its trajectory.
This document proposes a mobility management scheme for IP-based vehicular networks,
called Vehicular Mobility Management (VMM). The VMM is tailored
for a vehicular network architecture and a vehicular link model described in the IPWAVE problem
statement document .
Vehicle Neighbor Discovery (VND) is proposed as Extended IPv6 Neighbor Discovery (ND)
for IP-based vehicle networks to support the vehicle-to-vehicle or
the vehicle to Road-Side Unit (RSU) interactions. For an efficient IPv6 Stateless Address
Autoconfiguration (SLAAC) , VND adopts an optimized Address Registration
using a multihop Duplicate Address Detection (DAD). This multihop DAD enables a vehicle to have
a unique IP address in a multi-link subnet consisting of multiple wireless subnets with the same
IP prefix, which corresponds to wireless coverage of multiple RSUs. VND also
supports IP packet routing over a connected Vehicular Ad Hoc Network (VANET) by allowing
vehicles to exchange the prefixes of their internal networks through their external wireless
interface.
The mobility management in this multi-link subnet needs a new approach from the legacy
mobility management schemes. This document aims at an efficient mobility management scheme
called VMM to support efficient V2V, V2I, and V2X communications in a road network.
The VMM takes advantage of the mobility information (e.g.,a vehicle's speed, direction, and position)
and trajectory (i.e., navigation path) of each vehicle registered in the Traffic Control Center (TCC)
of the vehicular cloud.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 .
This document uses the terminology described in and .
In addition, the following new terms are defined as below:
DMM: Acronym for "Distributed Mobility Management" .
Mobility Anchor (MA): A node that maintains the IP addresses and
mobility information of vehicles in a road network to support
their address autoconfiguration and mobility management
with a binding table.
It has end-to-end connections with RSUs under its control.
On-Board Unit (OBU): A node that with a network interface (e.g., IEEE 802.11-OCB and
Cellular V2X (C-V2X) )
for wireless communications with other OBUs and RSUs, and may be connected to
in-vehicle's 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.
OCB: Acronym for "Outside the Context of a Basic Service Set" .
Road-Side Unit (RSU): A node that has physical communication devices
(e.g., IEEE 802.11-OCB and C-V2X) for wireless communication
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 cars parking areas.
Traffic Control Center (TCC): A node that maintains the 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.
Vehicular Cloud: A cloud infrastructure for vehicular networks, having
compute nodes, storage nodes, and network nodes.
WAVE: Acronym for "Wireless Access in Vehicular Environments"
.
This section describes a vehicular network architecture for V2V and V2I communication.
A vehicle and an RSU have their internal networks including in-vehicle devices or servers,
respectively.
A vehicular network architecture for V2I and V2V is illustrated in
. In this figure, there is a vehicular
cloud containing a TCC. The TCC has Mobility Anchors (MAs) responsible
for the vehicles mobility management. Each MA is in charge of
the mobility management of vehicles under its prefix domain, which is a multi-link
subnet of RSUs sharing the same prefix .
A vehicular network is a wireless network consisting of RSUs and vehicles. The RSUs
are interconnected via a wired network, allowing vehicles to build
VANETs via V2V and V2I communications.
In , three RSUs are deployed
either at intersections or along roadways. They are connected to an MA through
wired networks.
The vehicular network has two subnets, such as Subnet1 and Subnet2.
Subnet1 is a multi-link subnet consisting of multiple wireless coverage areas of
multiple RSUs, which share the same IPv6 prefix to construct a single
logical subnet .
That is, the RSU1 and RSU2 wireless links belong to Subnet1.
Thus, since Vehicle2 and Vehicle3 use the same prefix for Subnet1, and that are
within the wireless communication range, they can communicate directly with
each other. Note that in a multi-link subnet, a vehicle (e.g., Vehicle2 and
Vehicle3 in ) can configure
its global IPv6 address through an address registration procedure that includes
the multihop DAD specified in VND .
Subnet2 on the other hand, uses a different prefix than Subnet1. Vehicle4
residing in Subnet2 cannot communicate directly to Vehicle3 because it belongs to
a different subnet.
Vehicles can construct a connected VANET so they can communicate with each other
without relaying on RSU, but on the forwarding over the VANET.
In the case where two vehicles belong to the same multi-link subnet, but they
are not connected in the same VANET, they can use RSUs.
In , even though Vehicle1 is
disconnected from Vehicle3, they can communicate indirectly with each other
through RSUs such as RSU1 and RSU2.
This document specifies a mobility management scheme for the vehicular network architecture, as shown in
. Vehicle2 is supposed to communicate with the
corresponding node denoted as CN1, and Vehicle2
is moving in the wireless coverage of RSU1. When Vehicle2 moves out of
the coverage of RSU1 and moves into the coverage of RSU2 where RSU1 and RSU2
share the same prefix, packets sent by CN1 should be routed through RSU2 to Vehicle2.
Also, when Vehicle2 moves out of the coverage of RSU2 and moves into the coverage
of RSU3 where RSU2 and RSU3 use two different prefixes, the CN1 packets should
be delivered to Vehicle2 via RSU3. A handoff procedure allows a sender's packets to be
delivered to a destination vehicle which is moving within the wireless coverage areas.
This section explains the detailed procedure of mobility management
of a vehicle in a road network as shown in
.
A mobility management is required for the seamless communication of vehicles
moving between the RSUs.
When a vehicle moves into the coverage of another RSU, a different IP address
is assigned to the vehicle, the transport-layersession information
(i.e., an end-point's IP address) is reconfigured to avoid service
disruption. Considering this issue, this document proposes a handoff mechanism
for seamless communication.
In , the authors constructed a network-based mobility
management scheme using Proxy Mobile IPv6 (PMIPv6) ,
which is highly suitable for vehicular networks. This document uses a mobility
management procedure similar to PMIPv6, but uses a newly proposed Shared-Prefix model in
which vehicles in the same subnet share the same prefix.
shows the binding update flow when
a vehicle entered the RSU subnet. The RSUs act as Mobility Anchor Gateway
(MAG) defined in . When it receives an RS message
from a vehicle containing its mobility information (e.g., position, speed, and
direction), an RSU sends a Proxy Binding Update (PBU) message to its MA
. This contains a Mobility
Option including the vehicle's mobility information. The MA receives the PBU and
sets up a Binding Cache Entry (BCE) as well as a bi-directional tunnel
(denoted as Bi-Dir Tunnel in
)
between
the serving RSU and itself. Through this tunnel, all traffic packets to the
vehicle are encapsulated toward the RSU. Simultaneously, the MA sends back a
Proxy Binding Acknowledgment (PBA) message to the serving RSU. This serving RSU
receives the PBA and sets up a bi-directional tunnel with the MA. After this
binding update, the RSU sends back an RA message to the vehicle. This message includes
the RSU's prefix for the address autoconfiguration of the vehicle.
When the vehicle receives the RA message, it performs the address registration
procedure including a multihop DAD for its global IP address based on the prefix
announced by the RA message according to the VND .
In PMIPv6, an MA (i.e., LMA) allocates a unique prefix to each vehicle to guarantee the uniqueness of each address,
but in this document, an MA allocates in its domain a unique IP address to each vehicle with the same prefix through
the multihop-DAD-based address registration. This unique IP address allocation ensures that vehicles own unique IP
addresses in a multi-link subnet and can reduce the waste of IP prefixes in legacy PMIPv6.
When the vehicle changes its location and its current RSU (denoted as c-RSU)
detects that the vehicle is moving out of its coverage, the c-RSU reports
the leaving of the vehicle to the MA and de-register the binding via PBU.
With this report, the MA will send back a PBA to notice the de-register to c-RSU,
and get ready to detect new binding requests. If MA can figure out the new RSU (denoted as n-RSU)
based on the vehicle's trajectory, it will directly change the end-point of the tunnel into n-RSU's IP address for the vehicle.
shows the handoff
of a vehicle within one prefix domain (i.e., a multi-link subnet) with PMIPv6.
As shown in the figure, when the MA receives a new PBU from the n-RSU,
it changes the tunnel's end-point from the c-RSU to n-RSU.
If there are ongoing IP packets toward the vehicle, the MA
encapsulates the packets and then forwards them towards n-RSU.
Through this network-based mobility management, the vehicle is not aware of any
changes at its network layer and can maintain its transport-layer sessions
without any disruption.
If c-RSU and n-RSU are adjacent, that is, vehicles are moving in specified
routes with fixed RSU allocation, the procedure can be simplified by
constructing the bidirectional tunnel directly between them (cancel the intervention
of MA) to alleviate the traffic flow in MA as well as reduce handoff delay.
shows a vehicle handoff
within one prefix domain (as a multi-link subnet) with DMM .
The RSUs are in charge of detecting when a node joins or moves to
its domain. If the c-RSU detects that the vehicle is going to leave its coverage
and to enter the area of an adjacent RSU, it sends a PBU message to inform
n-RSU of the vehicle's handoff. If n-RSU receives the PBU message, it
constructs a bidirectional tunnel between c-RSU and itself, and then sends back
a PBA message as an acknowledgment to c-RSU.
If there are ongoing IP packets toward the vehicle, c-RSU encapsulates the
packets and then forwards them to n-RSU. When n-RSU detects the entrance of
the vehicle, it directly sends an RA message to the vehicle so that the vehicle
can assure that it is still connected to a router with its current prefix.
If the vehicle sends an RS message to n-RSU, n-RSU responds to the RS message by
replying to the vehicle with an RA .
When a vehicle moves from a prefix domain to another prefix domain,
a handoff between multiple prefix domains is required.
As shown in ,
when Vehicle3 moves from the subnet of RSU2 (i.e., Subnet1) to
the subnet of RSU3 (i.e., Subnet2), a multiple domain handoff is performed
through the cooperation of RSU2, RSU3, MA1 and MA2.
shows the handoff
of a vehicle between two prefix domains (i.e., two multi-link subnets) with PMIPv6.
When the vehicle moves out of its c-RSU belonging to
Subnet1, and moves into the n-RSU belonging to Subnet2,
c-RSU detects the vehicle's leaving and reports it to MA1.
MA1 figures out that the vehicle will get into the coverage of the n-RSU based on its trajectory
and sends MA2 a PBU message to inform MA2 that the vehicle will enter
the coverage of n-RSU belonging to MA2. MA2 sends a PBA message to n-RSU to inform that the vehicle
will enter the coverage of n-RSU along with handoff context
such as c-RSU's context information (e.g., c-RSU's link-local address and prefix called prefix1), and
the vehicle's context information (e.g., the vehicle's global IP address and MAC address).
After n-RSU receives the PBA message including the handoff context from MA2, it sets up
a bi-directional tunnel with MA2, and generates RA messages with c-RSU's context information.
That is, n-RSU pretends to be a router belonging to Subnet1.
When the vehicle receives RA from n-RSU, it can maintain its connection with its
corresponding node (i.e., CN1).
Note that n-RSU also sends RA messages with its domain prefix called prefix2. The vehicle
configures another global IP address with prefix2, and can use it for communication with
neighboring vehicles under the coverage of n-RSU.
If c-RSU and n-RSU are adjacent, that is, vehicles are moving in specified
routes with fixed RSU allocation, the procedure can be simplified by
constructing the bidirectional tunnel directly between them (cancel the intervention
of MAs) to alleviate the traffic flow in MA as well as reduce handoff delay.
shows the vehicle handoff
within two prefix domains (as two multi-link subnets) with DMM .
If c-RSU detects that the vehicle is going to leave its coverage
and to enter the area of an adjacent RSU (n-RSU) belonging to a different prefix domain,
it sends a PBU message to inform n-RSU that the vehicle will enter the coverage of n-RSU
along with handoff context such as c-RSU's context information (e.g., c-RSU's link-local
address and prefix called prefix1), and the vehicle's context information (e.g., the vehicle's global
IP address and MAC address). After n-RSU receives the PBA message including the handoff
context from c-RSU, it sets up a bi-directional tunnel with c-RSU, and generates RA messages
with c-RSU's context information. That is, n-RSU pretends to be a router belonging to Subnet1.
When the vehicle receives RA from n-RSU, it can maintain its connection with its
corresponding node (i.e., CN1).
Note that n-RSU also sends RA messages with its domain prefix called prefix2. The vehicle
configures another global IP address with prefix2, and can use it for communication with
neighboring vehicles under the coverage of n-RSU.
This document shares all the security issues of Vehicular ND
, Proxy MIPv6 , and
DMM .
Key words for use in RFCs to Indicate Requirement LevelsNeighbor Discovery for IP Version 6 (IPv6)IPv6 Stateless Address AutoconfigurationProxy Mobile IPv6Mobility Support in IPv6Requirements for Distributed Mobility ManagementDistributed Mobility Management: Current Practices and Gap AnalysisProxy Mobile IPv6 Extensions for Distributed Mobility ManagementIPv6 Wireless Access in Vehicular Environments (IPWAVE): Problem Statement and Use CasesVehicular Neighbor Discovery for IP-Based Vehicular NetworksVIP-WAVE: On the Feasibility of IP Communications in 802.11p Vehicular NetworksPart 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) SpecificationsIEEE Guide for Wireless Access in Vehicular Environments (WAVE) - ArchitectureArchitecture Enhancements for V2X Services
3GPP
This work was supported in part by Institute of Information &
Communications Technology Planning & Evaluation (IITP) grant
funded by the Korea Ministry of Science and ICT (MSIT) (2020-0-00395-003,
Standard Development of Blockchain based Network Management Automation
Technology).
This work was supported in part by the MSIT under the ITRC (Information
Technology Research Center) support program (IITP-2022-2017-0-01633)
supervised by the IITP.
This document is made by the group effort of IPWAVE working group.
Many people actively contributed to this document, such as
Carlos J. Bernardos and Russ Housley.
The authors sincerely appreciate their contributions.
The following are co-authors of this document:
Zhong Xiang -
Department of Electrical and Computer Engineering,
Sungkyunkwan University,
2066 Seobu-ro Jangan-gu,
Suwon, Gyeonggi-do 16419,
Republic of Korea.
EMail: xz618@skku.edu
The following changes are made from draft-jeong-ipwave-vehicular-mobility-management-07
This version updates the author list.