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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IPWAVE Working Group J. Jeong, Ed. 3 Internet-Draft Sungkyunkwan University 4 Intended status: Informational June 29, 2020 5 Expires: December 31, 2020 7 IPv6 Wireless Access in Vehicular Environments (IPWAVE): Problem 8 Statement and Use Cases 9 draft-ietf-ipwave-vehicular-networking-15 11 Abstract 13 This document discusses the problem statement and use cases of 14 IPv6-based vehicular networking for Intelligent Transportation 15 Systems (ITS). The main scenarios of vehicular communications are 16 vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), and 17 vehicle-to-everything (V2X) communications. First, this document 18 explains use cases using V2V, V2I, and V2X networking. Next, for 19 IPv6-based vehicular networks, it makes a gap analysis of current 20 IPv6 protocols (e.g., IPv6 Neighbor Discovery, Mobility Management, 21 and Security & Privacy), and then lists up requirements for the 22 extensions of those IPv6 protocols for IPv6-based vehicular 23 networking. 25 Status of This Memo 27 This Internet-Draft is submitted in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at https://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on December 31, 2020. 42 Copyright Notice 44 Copyright (c) 2020 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents 49 (https://trustee.ietf.org/license-info) in effect on the date of 50 publication of this document. Please review these documents 51 carefully, as they describe your rights and restrictions with respect 52 to this document. Code Components extracted from this document must 53 include Simplified BSD License text as described in Section 4.e of 54 the Trust Legal Provisions and are provided without warranty as 55 described in the Simplified BSD License. 57 Table of Contents 59 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 60 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 61 3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 6 62 3.1. V2V . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 63 3.2. V2I . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 64 3.3. V2X . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 65 4. Vehicular Networks . . . . . . . . . . . . . . . . . . . . . 11 66 4.1. Vehicular Network Architecture . . . . . . . . . . . . . 11 67 4.2. V2I-based Internetworking . . . . . . . . . . . . . . . . 16 68 4.3. V2V-based Internetworking . . . . . . . . . . . . . . . . 18 69 5. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 20 70 5.1. Neighbor Discovery . . . . . . . . . . . . . . . . . . . 21 71 5.1.1. Link Model . . . . . . . . . . . . . . . . . . . . . 22 72 5.1.2. MAC Address Pseudonym . . . . . . . . . . . . . . . . 24 73 5.1.3. Routing . . . . . . . . . . . . . . . . . . . . . . . 25 74 5.2. Mobility Management . . . . . . . . . . . . . . . . . . . 25 75 6. Security Considerations . . . . . . . . . . . . . . . . . . . 26 76 7. Informative References . . . . . . . . . . . . . . . . . . . 29 77 Appendix A. Changes from draft-ietf-ipwave-vehicular- 78 networking-14 . . . . . . . . . . . . . . . . . . . 36 79 Appendix B. Acknowledgments . . . . . . . . . . . . . . . . . . 36 80 Appendix C. Contributors . . . . . . . . . . . . . . . . . . . . 36 81 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 38 83 1. Introduction 85 Vehicular networking studies have mainly focused on improving safety 86 and efficiency, and also enabling entertainment in vehicular 87 networks. The Federal Communications Commission (FCC) in the US 88 allocated wireless channels for Dedicated Short-Range Communications 89 (DSRC) [DSRC] in the Intelligent Transportation Systems (ITS) with 90 the frequency band of 5.850 - 5.925 GHz (i.e., 5.9 GHz band). DSRC- 91 based wireless communications can support vehicle-to-vehicle (V2V), 92 vehicle-to-infrastructure (V2I), and vehicle-to-everything (V2X) 93 networking. The European Union (EU) allocated radio spectrum for 94 safety-related and non-safety-related applications of ITS with the 95 frequency band of 5.875 - 5.905 GHz, as part of the Commission 96 Decision 2008/671/EC [EU-2008-671-EC]. 98 For direct inter-vehicular wireless connectivity, IEEE has amended 99 standard 802.11 (commonly known as Wi-Fi) to enable safe driving 100 services based on DSRC for the Wireless Access in Vehicular 101 Environments (WAVE) system. The Physical Layer (L1) and Data Link 102 Layer (L2) issues are addressed in IEEE 802.11p [IEEE-802.11p] for 103 the PHY and MAC of the DSRC, while IEEE 1609.2 [WAVE-1609.2] covers 104 security aspects, IEEE 1609.3 [WAVE-1609.3] defines related services 105 at network and transport layers, and IEEE 1609.4 [WAVE-1609.4] 106 specifies the multi-channel operation. IEEE 802.11p was first a 107 separate amendment, but was later rolled into the base 802.11 108 standard (IEEE 802.11-2012) as IEEE 802.11 Outside the Context of a 109 Basic Service Set (OCB) in 2012 [IEEE-802.11-OCB]. 111 3GPP has standardized Cellular Vehicle-to-Everything (C-V2X) 112 communications to support V2X in LTE mobile networks (called LTE V2X) 113 and V2X in 5G mobile networks (called 5G V2X) [TS-23.285-3GPP] 114 [TR-22.886-3GPP][TS-23.287-3GPP]. With C-V2X, vehicles can directly 115 communicate with each other without relay nodes (e.g., eNodeB in LTE 116 and gNodeB in 5G). 118 Along with these WAVE standards and C-V2X standards, regardless of a 119 wireless access technology under the IP stack of a vehicle, vehicular 120 networks can operate IP mobility with IPv6 [RFC8200] and Mobile IPv6 121 protocols (e.g., Mobile IPv6 (MIPv6) [RFC6275], Proxy MIPv6 (PMIPv6) 122 [RFC5213], Distributed Mobility Management (DMM) [RFC7333], Locator/ 123 ID Separation Protocol (LISP) [RFC6830], and Asymmetric Extended 124 Route Optimization (AERO) [RFC6706]). In addition, ISO has approved 125 a standard specifying the IPv6 network protocols and services to be 126 used for Communications Access for Land Mobiles (CALM) [ISO-ITS-IPv6] 127 [ISO-ITS-IPv6-AMD1]. 129 This document describes use cases and a problem statement about 130 IPv6-based vehicular networking for ITS, which is named IPv6 Wireless 131 Access in Vehicular Environments (IPWAVE). First, it introduces the 132 use cases for using V2V, V2I, and V2X networking in ITS. Next, for 133 IPv6-based vehicular networks, it makes a gap analysis of current 134 IPv6 protocols (e.g., IPv6 Neighbor Discovery, Mobility Management, 135 and Security & Privacy), and then lists up requirements for the 136 extensions of those IPv6 protocols, which are tailored to IPv6-based 137 vehicular networking. Thus, this document is intended to motivate 138 development of key protocols for IPWAVE. 140 2. Terminology 142 This document uses the terminology described in [RFC8691]. In 143 addition, the following terms are defined below: 145 o Class-Based Safety Plan: A vehicle can make a safety plan by 146 classifying the surrounding vehicles into different groups for 147 safety purposes according to the geometrical relationship among 148 them. The vehicle groups can be classified as Line-of-Sight 149 Unsafe, Non-Line-of-Sight Unsafe, and Safe groups [CASD]. 151 o Context-Awareness: A vehicle can be aware of spatial-temporal 152 mobility information (e.g., position, speed, direction, and 153 acceleration/deceleration) of surrounding vehicles for both safety 154 and non-safety uses through sensing or communication [CASD]. 156 o DMM: "Distributed Mobility Management" [RFC7333][RFC7429]. 158 o Edge Computing (EC): It is the local computing near an access 159 network (i.e., edge network) for the sake of vehicles and 160 pedestrians. 162 o Edge Computing Device (ECD): It is a computing device (or server) 163 for edge computing for the sake of vehicles and pedestrians. 165 o Edge Network (EN): It is an access network that has an IP-RSU for 166 wireless communication with other vehicles having an IP-OBU and 167 wired communication with other network devices (e.g., routers, IP- 168 RSUs, ECDs, servers, and MA). It may have a Global Positioning 169 System (GPS) radio receiver for its position recognition and the 170 localization service for the sake of vehicles. 172 o IP-OBU: "Internet Protocol On-Board Unit": An IP-OBU denotes a 173 computer situated in a vehicle (e.g., car, bicycle, autobike, 174 motor cycle, and a similar one) and a device (e.g., smartphone and 175 IoT device). It has at least one IP interface that runs in IEEE 176 802.11-OCB and has an "OBU" transceiver. Also, it may have an IP 177 interface that runs in Cellular V2X (C-V2X) [TS-23.285-3GPP] 178 [TR-22.886-3GPP][TS-23.287-3GPP]. See the definition of the term 179 "OBU" in [RFC8691]. 181 o IP-RSU: "IP Roadside Unit": An IP-RSU is situated along the road. 182 It has at least two distinct IP-enabled interfaces. The wireless 183 PHY/MAC layer of at least one of its IP-enabled interfaces is 184 configured to operate in 802.11-OCB mode. An IP-RSU communicates 185 with the IP-OBU over an 802.11 wireless link operating in OCB 186 mode. Also, it may have an IP interface that runs in C-V2X along 187 with an "RSU" transceiver. An IP-RSU is similar to an Access 188 Network Router (ANR), defined in [RFC3753], and a Wireless 189 Termination Point (WTP), defined in [RFC5415]. See the definition 190 of the term "RSU" in [RFC8691]. 192 o LiDAR: "Light Detection and Ranging". It is a scanning device to 193 measure a distance to an object by emitting pulsed laser light and 194 measuring the reflected pulsed light. 196 o Mobility Anchor (MA): A node that maintains IPv6 addresses and 197 mobility information of vehicles in a road network to support 198 their IPv6 address autoconfiguration and mobility management with 199 a binding table. An MA has End-to-End (E2E) connections (e.g., 200 tunnels) with IP-RSUs under its control for the address 201 autoconfiguration and mobility management of the vehicles. This 202 MA is similar to a Local Mobility Anchor (LMA) in PMIPv6 [RFC5213] 203 for network-based mobility management. 205 o OCB: "Outside the Context of a Basic Service Set - BSS". It is a 206 mode of operation in which a Station (STA) is not a member of a 207 BSS and does not utilize IEEE Std 802.11 authentication, 208 association, or data confidentiality [IEEE-802.11-OCB]. 210 o 802.11-OCB: It refers to the mode specified in IEEE Std 211 802.11-2016 [IEEE-802.11-OCB] when the MIB attribute 212 dot11OCBActivited is 'true'. 214 o Platooning: Moving vehicles can be grouped together to reduce air- 215 resistance for energy efficiency and reduce the number of drivers 216 such that only the leading vehicle has a driver, and the other 217 vehicles are autonomous vehicles without a driver and closely 218 follow the leading vehicle [Truck-Platooning]. 220 o Traffic Control Center (TCC): A system that manages road 221 infrastructure nodes (e.g., IP-RSUs, MAs, traffic signals, and 222 loop detectors), and also maintains vehicular traffic statistics 223 (e.g., average vehicle speed and vehicle inter-arrival time per 224 road segment) and vehicle information (e.g., a vehicle's 225 identifier, position, direction, speed, and trajectory as a 226 navigation path). TCC is part of a vehicular cloud for vehicular 227 networks. 229 o Vehicle: A Vehicle in this document is a node that has an IP-OBU 230 for wireless communication with other vehicles and IP-RSUs. It 231 has a GPS radio navigation receiver for efficient navigation. Any 232 device having an IP-OBU and a GPS receiver (e.g., smartphone and 233 table PC) can be regarded as a vehicle in this document. 235 o Vehicular Ad Hoc Network (VANET): A network that consists of 236 vehicles interconnected by wireless communication. Two vehicles 237 in a VANET can communicate with each other using other vehicles as 238 relays even where they are out of one-hop wireless communication 239 range. 241 o Vehicular Cloud: A cloud infrastructure for vehicular networks, 242 having compute nodes, storage nodes, and network forwarding 243 elements (e.g., switch and router). 245 o V2D: "Vehicle to Device". It is the wireless communication 246 between a vehicle and a device (e.g., smartphone and IoT device). 248 o V2I2D: "Vehicle to Infrastructure to Device". It is the wireless 249 communication between a vehicle and a device (e.g., smartphone and 250 IoT device) via an infrastructure node (e.g., IP-RSU). 252 o V2I2V: "Vehicle to Infrastructure to Vehicle". It is the wireless 253 communication between a vehicle and another vehicle via an 254 infrastructure node (e.g., IP-RSU). 256 o V2I2X: "Vehicle to Infrastructure to Everything". It is the 257 wireless communication between a vehicle and another entity (e.g., 258 vehicle, smartphone, and IoT device) via an infrastructure node 259 (e.g., IP-RSU). 261 o V2X: "Vehicle to Everything". It is the wireless communication 262 between a vehicle and any entity (e.g., vehicle, infrastructure 263 node, smartphone, and IoT device), including V2V, V2I, and V2D. 265 o VIP: "Vehicular Internet Protocol". It is an IPv6 extension for 266 vehicular networks including V2V, V2I, and V2X. 268 o VMM: "Vehicular Mobility Management". It is an IPv6-based 269 mobility management for vehicular networks. 271 o VND: "Vehicular Neighbor Discovery". It is an IPv6 ND extension 272 for vehicular networks. 274 o VSP: "Vehicular Security and Privacy". It is an IPv6-based 275 security and privacy for vehicular networks. 277 o WAVE: "Wireless Access in Vehicular Environments" [WAVE-1609.0]. 279 3. Use Cases 281 This section explains use cases of V2V, V2I, and V2X networking. The 282 use cases of the V2X networking exclude the ones of the V2V and V2I 283 networking, but include Vehicle-to-Pedestrian (V2P) and Vehicle-to- 284 Device (V2D). 286 IP is widely used among popular end-user devices (e.g., smartphone 287 and tablet) in the Internet. Applications (e.g., navigator 288 application) for those devices can be extended such that the V2V use 289 cases in this section can work with IPv6 as a network layer protocol 290 and IEEE 802.11-OCB as a link layer protocol. In addition, IPv6 291 security needs to be extended to support those V2V use cases in a 292 safe, secure, privacy-preserving way. 294 The use cases presented in this section serve as the description and 295 motivation for the need to extend IPv6 and its protocols to 296 facilitate "Vehicular IPv6". Section 5 summarizes the overall 297 problem statement and IPv6 requirements. Note that the adjective 298 "Vehicular" in this document is used to represent extensions of 299 existing protocols such as IPv6 Neighbor Discovery, IPv6 Mobility 300 Management (e.g., PMIPv6 [RFC5213] and DMM [RFC7429]), and IPv6 301 Security and Privacy Mechanisms rather than new "vehicular-specific" 302 functions. Refer to Section 5 for the problem statement of the 303 requirements of vehicular IPv6. 305 3.1. V2V 307 The use cases of V2V networking discussed in this section include 309 o Context-aware navigation for safe driving and collision avoidance; 311 o Cooperative adaptive cruise control in a roadway; 313 o Platooning in a highway; 315 o Cooperative environment sensing. 317 These four techniques will be important elements for self-driving 318 vehicles. 320 Context-Aware Safety Driving (CASD) navigator [CASD] can help drivers 321 to drive safely by alerting them to dangerous obstacles and 322 situations. That is, a CASD navigator displays obstacles or 323 neighboring vehicles relevant to possible collisions in real-time 324 through V2V networking. CASD provides vehicles with a class-based 325 automatic safety action plan, which considers three situations, 326 namely, the Line-of-Sight unsafe, Non-Line-of-Sight unsafe, and safe 327 situations. This action plan can be put into action among multiple 328 vehicles using V2V networking. 330 Cooperative Adaptive Cruise Control (CACC) [CA-Cruise-Control] helps 331 individual vehicles to adapt their speed autonomously through V2V 332 communication among vehicles according to the mobility of their 333 predecessor and successor vehicles in an urban roadway or a highway. 334 Thus, CACC can help adjacent vehicles to efficiently adjust their 335 speed in an interactive way through V2V networking in order to avoid 336 a collision. 338 Platooning [Truck-Platooning] allows a series (or group) of vehicles 339 (e.g., trucks) to follow each other very closely. Trucks can use V2V 340 communication in addition to forward sensors in order to maintain 341 constant clearance between two consecutive vehicles at very short 342 gaps (from 3 meters to 10 meters). Platooning can maximize the 343 throughput of vehicular traffic in a highway and reduce the gas 344 consumption because the leading vehicle can help the following 345 vehicles to experience less air resistance. 347 Cooperative-environment-sensing use cases suggest that vehicles can 348 share environmental information (e.g., air pollution, hazards/ 349 obstacles, slippery areas by snow or rain, road accidents, traffic 350 congestion, and driving behaviors of neighboring vehicles) from 351 various vehicle-mounted sensors, such as radars, LiDARs, and cameras, 352 with other vehicles and pedestrians. [Automotive-Sensing] introduces 353 millimeter-wave vehicular communication for massive automotive 354 sensing. A lot of data can be generated by those sensors, and these 355 data typically need to be routed to different destinations. In 356 addition, from the perspective of driverless vehicles, it is expected 357 that driverless vehicles can be mixed with driver-operated vehicles. 358 Through cooperative environment sensing, driver-operated vehicles can 359 use environmental information sensed by driverless vehicles for 360 better interaction with the other vehicles and environment. Vehicles 361 can also share their intended maneuvering information (e.g., lane 362 change, speed change, ramp in-and-out, cut-in, and abrupt braking) 363 with neighboring vehicles. Thus, this information sharing can help 364 the vehicles behave as more efficient traffic flows and minimize 365 unnecessary acceleration and deceleration to achieve the best ride 366 comfort. 368 To encourage more vehicles to participate in this cooperative 369 environmental sensing, a reward system will be needed. Sensing 370 activities of each vehicle need to be logged in either a central way 371 through a logging server (e.g., TCC) in the vehicular cloud or a 372 distributed way (e.g., blockchain [Bitcoin]) through other vehicles 373 or infrastructure. In the case of a blockchain, each sensing message 374 from a vehicle can be treated as a transaction and the neighboring 375 vehicles can play the role of peers in a consensus method of a 376 blockchain such as Proof of Work (PoW) and Proof of Stake (PoS) 377 [Bitcoin][Vehicular-BlockChain]. 379 The existing IPv6 protocol does not support wireless single-hop V2V 380 communications as well as wireless multihop V2V communications. 381 Thus, the IPv6 needs to support both single-hop and multihop 382 communications in a wireless medium so that vehicles can communicate 383 with each other by V2V communications to share either an emergency 384 situation or road hazard in a highway. 386 To support applications of these V2V use cases, the functions of IPv6 387 such as VND and VSP are prerequisites for IPv6-based packet exchange 388 and secure, safe communication between two vehicles. 390 3.2. V2I 392 The use cases of V2I networking discussed in this section include 394 o Navigation service; 396 o Energy-efficient speed recommendation service; 398 o Accident notification service; 400 o Electric vehicle (EV) charging service. 402 A navigation service, for example, the Self-Adaptive Interactive 403 Navigation Tool(SAINT) [SAINT], using V2I networking interacts with a 404 TCC for the large-scale/long-range road traffic optimization and can 405 guide individual vehicles along appropriate navigation paths in real 406 time. The enhanced version of SAINT [SAINTplus] can give fast moving 407 paths to emergency vehicles (e.g., ambulance and fire engine) to let 408 them reach an accident spot while redirecting other vehicles near the 409 accident spot into efficient detour paths. 411 Either a TCC or an ECD can recommend an energy-efficient speed to a 412 vehicle that depends on its traffic environment and traffic signal 413 scheduling [SignalGuru]. For example, when a vehicle approaches an 414 intersection area and a red traffic light for the vehicle becomes 415 turned on, it needs to reduce its speed to save fuel consumption. In 416 this case, either a TCC or an ECD, which has the up-to-date 417 trajectory of the vehicle and the traffic light schedule, can notify 418 the vehicle of an appropriate speed for fuel efficiency. 419 [Fuel-Efficient] studies fuel-efficient route and speed plans for 420 platooned trucks. 422 The emergency communication between accident vehicles (or emergency 423 vehicles) and a TCC can be performed via either IP-RSU or 4G-LTE 424 networks. The First Responder Network Authority (FirstNet) 425 [FirstNet] is provided by the US government to establish, operate, 426 and maintain an interoperable public safety broadband network for 427 safety and security network services, e.g., emergency calls. The 428 construction of the nationwide FirstNet network requires each state 429 in the US to have a Radio Access Network (RAN) that will connect to 430 the FirstNet's network core. The current RAN is mainly constructed 431 using 4G-LTE for the communication between a vehicle and an 432 infrastructure node (i.e., V2I) [FirstNet-Report], but it is expected 433 that DSRC-based vehicular networks [DSRC] will be available for V2I 434 and V2V in the near future. 436 An EV charging service with V2I can facilitates the efficient battery 437 charging of EVs. In the case where an EV charging station is 438 connected to an IP-RSU, an EV can be guided toward the deck of the EV 439 charging station through a battery charging server connected to the 440 IP-RSU. In addition to this EV charging service, other value-added 441 services (e.g., air firmware/software update and media streaming) can 442 be provided to an EV while it is charging its battery at the EV 443 charging station. 445 The existing IPv6 protocol does not support wireless multihop V2I 446 communications in a highway where RSUs are sparsely deployed, so a 447 vehicle can reach the wireless coverage of an RSU through the 448 multihop data forwarding of intermediate vehicles. Thus, IPv6 needs 449 to be extended for multihop V2I communications. 451 To support applications of these V2I use cases, the functions of IPv6 452 such as VND, VMM, and VSP are prerequisites for IPv6-based packet 453 exchange, transport-layer session continuity, and secure, safe 454 communication between a vehicle and a server in the vehicular cloud. 456 3.3. V2X 458 The use case of V2X networking discussed in this section is for a 459 pedestrian protection service. 461 A pedestrian protection service, such as Safety-Aware Navigation 462 Application (SANA) [SANA], using V2I2P networking can reduce the 463 collision of a vehicle and a pedestrian carrying a smartphone 464 equipped with a network device for wireless communication (e.g., Wi- 465 Fi) with an IP-RSU. Vehicles and pedestrians can also communicate 466 with each other via an IP-RSU. An edge computing device behind the 467 IP-RSU can collect the mobility information from vehicles and 468 pedestrians, compute wireless communication scheduling for the sake 469 of them. This scheduling can save the battery of each pedestrian's 470 smartphone by allowing it to work in sleeping mode before the 471 communication with vehicles, considering their mobility. 473 For Vehicle-to-Pedestrian (V2P), a vehicle can directly communicate 474 with a pedestrian's smartphone by V2X without IP-RSU relaying. 475 Light-weight mobile nodes such as bicycles may also communicate 476 directly with a vehicle for collision avoidance using V2V. 478 The existing IPv6 protocol does not support wireless multihop V2X (or 479 V2I2X) communications in an urban road network where RSUs are 480 deployed at intersections, so a vehicle (or a pedestrian's 481 smartphone) can reach the wireless coverage of an RSU through the 482 multihop data forwarding of intermediate vehicles (or pedestrians' 483 smartphones). Thus, IPv6 needs to be extended for multihop V2X (or 484 V2I2X) communications. 486 To support applications of these V2X use cases, the functions of IPv6 487 such as VND, VMM, and VSP are prerequisites for IPv6-based packet 488 exchange, transport-layer session continuity, and secure, safe 489 communication between a vehicle and a pedestrian either directly or 490 indirectly via an IP-RSU. 492 4. Vehicular Networks 494 This section describes an example vehicular network architecture 495 supporting V2V, V2I, and V2X communications in vehicular networks. 496 It describes an internal network within a vehicle or an edge network 497 (called EN). It explains not only the internetworking between the 498 internal networks of a vehicle and an EN via wireless links, but also 499 the internetworking between the internal networks of two vehicles via 500 wireless links. 502 4.1. Vehicular Network Architecture 504 Figure 1 shows an example vehicular network architecture for V2I and 505 V2V in a road network [OMNI-Interface]. The vehicular network 506 architecture contains vehicles (including IP-OBU), IP-RSUs, Mobility 507 Anchor, Traffic Control Center, and Vehicular Cloud as components. 508 Note that the components of the vehicular network architecture can be 509 mapped to those of an IP-based aeronautical network architecture in 510 [OMNI-Interface], as shown in Figure 2. 512 Traffic Control Center in Vehicular Cloud 513 ******************************************* 514 +-------------+ * * 515 |Corresponding| * +-----------------+ * 516 | Node |<->* | Mobility Anchor | * 517 +-------------+ * +-----------------+ * 518 * ^ * 519 * | * 520 * v * 521 ******************************************* 522 ^ ^ ^ 523 | | | 524 | | | 525 v v v 526 +---------+ +---------+ +---------+ 527 | IP-RSU1 |<--------->| IP-RSU2 |<--------->| IP-RSU3 | 528 +---------+ +---------+ +---------+ 529 ^ ^ ^ 530 : : : 531 +-----------------+ +-----------------+ +-----------------+ 532 | : V2I | | : V2I | | : V2I | 533 | v | | v | | v | 534 +--------+ | +--------+ | | +--------+ | | +--------+ | 535 |Vehicle1|===> |Vehicle2|===>| | |Vehicle3|===>| | |Vehicle4|===>| 536 +--------+<...>+--------+<........>+--------+ | | +--------+ | 537 V2V ^ V2V ^ | | ^ | 538 | : V2V | | : V2V | | : V2V | 539 | v | | v | | v | 540 | +--------+ | | +--------+ | | +--------+ | 541 | |Vehicle5|===> | | |Vehicle6|===>| | |Vehicle7|==>| 542 | +--------+ | | +--------+ | | +--------+ | 543 +-----------------+ +-----------------+ +-----------------+ 544 Subnet1 Subnet2 Subnet3 545 (Prefix1) (Prefix2) (Prefix3) 547 <----> Wired Link <....> Wireless Link ===> Moving Direction 549 Figure 1: An Example Vehicular Network Architecture for V2I and V2V 550 +-------------------+------------------------------------+ 551 | Vehicular Network | Aeronautical Network | 552 +===================+====================================+ 553 | IP-RSU | Access Router (AR) | 554 +-------------------+------------------------------------+ 555 | Vehicle (IP-OBU) | Mobile Node (MN) | 556 +-------------------+------------------------------------+ 557 | Moving Network | End User Network (EUN) | 558 +-------------------+------------------------------------+ 559 | Mobility Anchor | Mobility Service Endpoint (MSE) | 560 +-------------------+------------------------------------+ 561 | Vehicular Cloud | Internetwork (INET) Routing System | 562 +-------------------+------------------------------------+ 564 Figure 2: Mapping between Vehicular Network Components and 565 Aeronautical Network Components 567 These components are not mandatory, and they can be deployed into 568 vehicular networks in various ways. Some of them (e.g., Mobility 569 Anchor, Traffic Control Center, and Vehicular Cloud) may not be 570 needed for the vehicular networks according to target use cases in 571 Section 3. 573 An existing network architecture (e.g., an IP-based aeronautical 574 network architecture [OMNI-Interface], a network architecture of 575 PMIPv6 [RFC5213], and a low-power and lossy network architecture 576 [RFC6550]) can be extended to a vehicular network architecture for 577 multihop V2V, V2I, and V2X, as shown in Figure 1. In a highway 578 scenario, a vehicle may not access an RSU directly because of the 579 distance of the DSRC coverage (up to 1 km). For example, RPL (IPv6 580 Routing Protocol for Low-Power and Lossy Networks) [RFC6550] can be 581 extended to support a multihop V2I since a vehicle can take advantage 582 of other vehicles as relay nodes to reach the RSU. Also, RPL can be 583 extended to support both multihop V2V and V2X in the similar way. 585 As shown in this figure, IP-RSUs as routers and vehicles with IP-OBU 586 have wireless media interfaces for VANET. Furthermore, the wireless 587 media interfaces are autoconfigured with a global IPv6 prefix (e.g., 588 2001:DB8:1:1::/64) to support both V2V and V2I networking. Note that 589 2001:DB8::/32 is a documentation prefix [RFC3849] for example 590 prefixes in this document, and also that any routable IPv6 address 591 needs to be routable in a VANET and a vehicular network including IP- 592 RSUs. 594 In Figure 1, three IP-RSUs (IP-RSU1, IP-RSU2, and IP-RSU3) are 595 deployed in the road network and are connected with each other 596 through the wired networks (e.g., Ethernet). A Traffic Control 597 Center (TCC) is connected to the Vehicular Cloud for the management 598 of IP-RSUs and vehicles in the road network. A Mobility Anchor (MA) 599 may be located in the TCC as a mobility management controller. 600 Vehicle2, Vehicle3, and Vehicle4 are wirelessly connected to IP-RSU1, 601 IP-RSU2, and IP-RSU3, respectively. The three wireless networks of 602 IP-RSU1, IP-RSU2, and IP-RSU3 can belong to three different subnets 603 (i.e., Subnet1, Subnet2, and Subnet3), respectively. Those three 604 subnets use three different prefixes (i.e., Prefix1, Prefix2, and 605 Prefix3). 607 Multiple vehicles under the coverage of an RSU share a prefix such 608 that mobile nodes share a prefix of a Wi-Fi access point in a 609 wireless LAN. This is a natural characteristic in infrastructure- 610 based wireless networks. For example, in Figure 1, two vehicles 611 (i.e., Vehicle2, and Vehicle5) can use Prefix 1 to configure their 612 IPv6 global addresses for V2I communication. 614 A single subnet prefix announced by an RSU can span multiple vehicles 615 in VANET. For example, in Figure 1, for Prefix 1, three vehicles 616 (i.e., Vehicle1, Vehicle2, and Vehicle5) can construct a connected 617 VANET. Also, for Prefix 2, two vehicles (i.e., Vehicle3 and 618 Vehicle6) can construct another connected VANET, and for Prefix 3, 619 two vehicles (i.e., Vehicle4 and Vehicle7) can construct another 620 connected VANET. 622 In wireless subnets in vehicular networks (e.g., Subnet1 and Subnet2 623 in Figure 1), vehicles can construct a connected VANET (with an 624 arbitrary graph topology) and can communicate with each other via V2V 625 communication. Vehicle1 can communicate with Vehicle2 via V2V 626 communication, and Vehicle2 can communicate with Vehicle3 via V2V 627 communication because they are within the wireless communication 628 range of each other. On the other hand, Vehicle3 can communicate 629 with Vehicle4 via the vehicular infrastructure (i.e., IP-RSU2 and IP- 630 RSU3) by employing V2I (i.e., V2I2V) communication because they are 631 not within the wireless communication range of each other. 633 For IPv6 packets transported over IEEE 802.11-OCB, [RFC8691] 634 specifies several details, including Maximum Transmission Unit (MTU), 635 frame format, link-local address, address mapping for unicast and 636 multicast, stateless autoconfiguration, and subnet structure. An 637 Ethernet Adaptation (EA) layer is in charge of transforming some 638 parameters between the IEEE 802.11 MAC layer and the IPv6 network 639 layer, which is located between the IEEE 802.11-OCB's logical link 640 control layer and the IPv6 network layer. This IPv6 over 802.11-OCB 641 can be used for both V2V and V2I in IPv6-based vehicular networks. 643 An IPv6 mobility solution is needed for the guarantee of 644 communication continuity in vehicular networks so that a vehicle's 645 TCP session can be continued, or UDP packets can be delivered to a 646 vehicle as a destination without loss while it moves from an IP-RSU's 647 wireless coverage to another IP-RSU's wireless coverage. In 648 Figure 1, assuming that Vehicle2 has a TCP session (or a UDP session) 649 with a corresponding node in the vehicular cloud, Vehicle2 can move 650 from IP-RSU1's wireless coverage to IP-RSU2's wireless coverage. In 651 this case, a handover for Vehicle2 needs to be performed by either a 652 host-based mobility management scheme (e.g., MIPv6 [RFC6275]) or a 653 network-based mobility management scheme (e.g., PMIPv6 [RFC5213]). 655 In the host-based mobility scheme (e.g., MIPv6), an IP-RSU plays a 656 role of a home agent. On the other hand, in the network-based 657 mobility scheme (e.g., PMIPv6, an MA plays a role of a mobility 658 management controller such as a Local Mobility Anchor (LMA) in 659 PMIPv6, which also serves vehicles as a home agent, and an IP-RSU 660 plays a role of an access router such as a Mobile Access Gateway 661 (MAG) in PMIPv6 [RFC5213]. The host-based mobility scheme needs 662 client functionality in IPv6 stack of a vehicle as a mobile node for 663 mobility signaling message exchange between the vehicle and home 664 agent. On the other hand, the network-based mobility scheme does not 665 need such a client functionality for a vehicle because the network 666 infrastructure node (e.g., MAG in PMIPv6) as a proxy mobility agent 667 handles the mobility signaling message exchange with the home agent 668 (e.g., LMA in PMIPv6) for the sake of the vehicle. 670 There are a scalability issue and a route optimization issue in the 671 network-based mobility scheme (e.g., PMIPv6) when an MA covers a 672 large vehicular network governing many IP-RSUs. In this case, a 673 distributed mobility scheme (e.g., DMM [RFC7429]) can mitigate the 674 scalability issue by distributing multiple MAs in the vehicular 675 network such that they are positioned closer to vehicles for route 676 optimization and bottleneck mitigation in a central MA in the 677 network-based mobility scheme. All these mobility approaches (i.e., 678 a host-based mobility scheme, network-based mobility scheme, and 679 distributed mobility scheme) and a hybrid approach of a combination 680 of them need to provide an efficient mobility service to vehicles 681 moving fast and moving along with the relatively predictable 682 trajectories along the roadways. 684 In vehicular networks, the control plane can be separated from the 685 data plane for efficient mobility management and data forwarding by 686 using the concept of Software-Defined Networking (SDN) 687 [RFC7149][DMM-FPC]. Note that Forwarding Policy Configuration (FPC) 688 in [DMM-FPC], which is a flexible mobility management system, can 689 manage the separation of data-plane and control-plane in DMM. In 690 SDN, the control plane and data plane are separated for the efficient 691 management of forwarding elements (e.g., switches and routers) where 692 an SDN controller configures the forwarding elements in a centralized 693 way and they perform packet forwarding according to their forwarding 694 tables that are configured by the SDN controller. An MA as an SDN 695 controller needs to efficiently configure and monitor its IP-RSUs and 696 vehicles for mobility management, location management, and security 697 services. 699 The mobility information of a GPS receiver mounted in its vehicle 700 (e.g., position, speed, and direction) can be used to accommodate 701 mobility-aware proactive handover schemes, which can perform the 702 handover of a vehicle according to its mobility and the wireless 703 signal strength of a vehicle and an IP-RSU in a proactive way. 705 Vehicles can use the TCC as their Home Network having a home agent 706 for mobility management as in MIPv6 [RFC6275] and PMIPv6 [RFC5213], 707 so the TCC (or an MA inside the TCC) maintains the mobility 708 information of vehicles for location management. IP tunneling over 709 the wireless link should be avoided for performance efficiency. 710 Also, in vehicular networks, asymmetric links sometimes exist and 711 must be considered for wireless communications such as V2V and V2I. 713 4.2. V2I-based Internetworking 715 This section discusses the internetworking between a vehicle's 716 internal network (i.e., moving network) and an EN's internal network 717 (i.e., fixed network) via V2I communication. The internal network of 718 a vehicle is nowadays constructed with Ethernet by many automotive 719 vendors [In-Car-Network]. Note that an EN can accommodate multiple 720 routers (or switches) and servers (e.g., ECDs, navigation server, and 721 DNS server) in its internal network. 723 A vehicle's internal network often uses Ethernet to interconnect 724 Electronic Control Units (ECUs) in the vehicle. The internal network 725 can support Wi-Fi and Bluetooth to accommodate a driver's and 726 passenger's mobile devices (e.g., smartphone or tablet). The network 727 topology and subnetting depend on each vendor's network configuration 728 for a vehicle and an EN. It is reasonable to consider the 729 interaction between the internal network and an external network 730 within another vehicle or an EN. 732 As shown in Figure 3, as internal networks, a vehicle's moving 733 network and an EN's fixed network are self-contained networks having 734 multiple subnets and having an edge router (e.g., IP-OBU and IP-RSU) 735 for the communication with another vehicle or another EN. The 736 internetworking between two internal networks via V2I communication 737 requires the exchange of the network parameters and the network 738 prefixes of the internal networks. For the efficiency, the network 739 prefixes of the internal networks (as a moving network) in a vehicle 740 need to be delegated and configured automatically. Note that a 741 moving network's network prefix can be called a Mobile Network Prefix 742 (MNP) [OMNI-Interface]. 744 +-----------------+ 745 (*)<........>(*) +----->| Vehicular Cloud | 746 2001:DB8:1:1::/64 | | | +-----------------+ 747 +------------------------------+ +---------------------------------+ 748 | v | | v v | 749 | +-------+ +-------+ | | +-------+ +-------+ | 750 | | Host1 | |IP-OBU1| | | |IP-RSU1| | Host3 | | 751 | +-------+ +-------+ | | +-------+ +-------+ | 752 | ^ ^ | | ^ ^ | 753 | | | | | | | | 754 | v v | | v v | 755 | ---------------------------- | | ------------------------------- | 756 | 2001:DB8:10:1::/64 ^ | | ^ 2001:DB8:20:1::/64 | 757 | | | | | | 758 | v | | v | 759 | +-------+ +-------+ | | +-------+ +-------+ +-------+ | 760 | | Host2 | |Router1| | | |Router2| |Server1|...|ServerN| | 761 | +-------+ +-------+ | | +-------+ +-------+ +-------+ | 762 | ^ ^ | | ^ ^ ^ | 763 | | | | | | | | | 764 | v v | | v v v | 765 | ---------------------------- | | ------------------------------- | 766 | 2001:DB8:10:2::/64 | | 2001:DB8:20:2::/64 | 767 +------------------------------+ +---------------------------------+ 768 Vehicle1 (Moving Network1) EN1 (Fixed Network1) 770 <----> Wired Link <....> Wireless Link (*) Antenna 772 Figure 3: Internetworking between Vehicle and Edge Network 774 Figure 3 also shows the internetworking between the vehicle's moving 775 network and the EN's fixed network. There exists an internal network 776 (Moving Network1) inside Vehicle1. Vehicle1 has two hosts (Host1 and 777 Host2), and two routers (IP-OBU1 and Router1). There exists another 778 internal network (Fixed Network1) inside EN1. EN1 has one host 779 (Host3), two routers (IP-RSU1 and Router2), and the collection of 780 servers (Server1 to ServerN) for various services in the road 781 networks, such as the emergency notification and navigation. 782 Vehicle1's IP-OBU1 (as a mobile router) and EN1's IP-RSU1 (as a fixed 783 router) use 2001:DB8:1:1::/64 for an external link (e.g., DSRC) for 784 V2I networking. Thus, a host (Host1) in Vehicle1 can communicate 785 with a server (Server1) in EN1 for a vehicular service through 786 Vehicle1's moving network, a wireless link between IP-OBU1 and IP- 787 RSU1, and EN1's fixed network. 789 For the IPv6 communication between an IP-OBU and an IP-RSU or between 790 two neighboring IP-OBUs, they need to know the network parameters, 791 which include MAC layer and IPv6 layer information. The MAC layer 792 information includes wireless link layer parameters, transmission 793 power level, and the MAC address of an external network interface for 794 the internetworking with another IP-OBU or IP-RSU. The IPv6 layer 795 information includes the IPv6 address and network prefix of an 796 external network interface for the internetworking with another IP- 797 OBU or IP-RSU. 799 Through the mutual knowledge of the network parameters of internal 800 networks, packets can be transmitted between the vehicle's moving 801 network and the EN's fixed network. Thus, V2I requires an efficient 802 protocol for the mutual knowledge of network parameters. 804 As shown in Figure 3, global IPv6 addresses are used for the wireless 805 link interfaces for IP-OBU and IP-RSU, but IPv6 Unique Local 806 Addresses (ULAs) [RFC4193] can also be used for those wireless link 807 interfaces as long as IPv6 packets can be routed to them in the 808 vehicular networks [OMNI-Interface]. For the guarantee of the 809 uniqueness of an IPv6 address, the configuration and control overhead 810 of the DAD of the wireless link interfaces should be minimized to 811 support the V2I and V2X communications of vehicles moving fast along 812 roadways. 814 4.3. V2V-based Internetworking 816 This section discusses the internetworking between the moving 817 networks of two neighboring vehicles via V2V communication. 819 Figure 4 shows the internetworking between the moving networks of two 820 neighboring vehicles. There exists an internal network (Moving 821 Network1) inside Vehicle1. Vehicle1 has two hosts (Host1 and Host2), 822 and two routers (IP-OBU1 and Router1). There exists another internal 823 network (Moving Network2) inside Vehicle2. Vehicle2 has two hosts 824 (Host3 and Host4), and two routers (IP-OBU2 and Router2). Vehicle1's 825 IP-OBU1 (as a mobile router) and Vehicle2's IP-OBU2 (as a mobile 826 router) use 2001:DB8:1:1::/64 for an external link (e.g., DSRC) for 827 V2V networking. Thus, a host (Host1) in Vehicle1 can communicate 828 with another host (Host3) in Vehicle2 for a vehicular service through 829 Vehicle1's moving network, a wireless link between IP-OBU1 and IP- 830 OBU2, and Vehicle2's moving network. 832 (*)<..........>(*) 833 2001:DB8:1:1::/64 | | 834 +------------------------------+ +------------------------------+ 835 | v | | v | 836 | +-------+ +-------+ | | +-------+ +-------+ | 837 | | Host1 | |IP-OBU1| | | |IP-OBU2| | Host3 | | 838 | +-------+ +-------+ | | +-------+ +-------+ | 839 | ^ ^ | | ^ ^ | 840 | | | | | | | | 841 | v v | | v v | 842 | ---------------------------- | | ---------------------------- | 843 | 2001:DB8:10:1::/64 ^ | | ^ 2001:DB8:30:1::/64 | 844 | | | | | | 845 | v | | v | 846 | +-------+ +-------+ | | +-------+ +-------+ | 847 | | Host2 | |Router1| | | |Router2| | Host4 | | 848 | +-------+ +-------+ | | +-------+ +-------+ | 849 | ^ ^ | | ^ ^ | 850 | | | | | | | | 851 | v v | | v v | 852 | ---------------------------- | | ---------------------------- | 853 | 2001:DB8:10:2::/64 | | 2001:DB8:30:2::/64 | 854 +------------------------------+ +------------------------------+ 855 Vehicle1 (Moving Network1) Vehicle2 (Moving Network2) 857 <----> Wired Link <....> Wireless Link (*) Antenna 859 Figure 4: Internetworking between Two Vehicles 861 As a V2V use case in Section 3.1, Figure 5 shows the linear network 862 topology of platooning vehicles for V2V communications where Vehicle3 863 is the leading vehicle with a driver, and Vehicle2 and Vehicle1 are 864 the following vehicles without drivers. 866 (*)<..................>(*)<..................>(*) 867 | | | 868 +-----------+ +-----------+ +-----------+ 869 | | | | | | 870 | +-------+ | | +-------+ | | +-------+ | 871 | |IP-OBU1| | | |IP-OBU2| | | |IP-OBU3| | 872 | +-------+ | | +-------+ | | +-------+ | 873 | ^ | | ^ | | ^ | 874 | | |=====> | | |=====> | | |=====> 875 | v | | v | | v | 876 | +-------+ | | +-------+ | | +-------+ | 877 | | Host1 | | | | Host2 | | | | Host3 | | 878 | +-------+ | | +-------+ | | +-------+ | 879 | | | | | | 880 +-----------+ +-----------+ +-----------+ 881 Vehicle1 Vehicle2 Vehicle3 883 <----> Wired Link <....> Wireless Link ===> Moving Direction 884 (*) Antenna 886 Figure 5: Multihop Internetworking between Two Vehicle Networks 888 As shown in Figure 5, multihop internetworking is feasible among the 889 moving networks of three vehicles in the same VANET. For example, 890 Host1 in Vehicle1 can communicate with Host3 in Vehicle3 via IP-OBU1 891 in Vehicle1, IP-OBU2 in Vehicle2, and IP-OBU3 in Vehicle3 in the 892 linear network, as shown in the figure. 894 5. Problem Statement 896 In order to specify protocols using the architecture mentioned in 897 Section 4.1, IPv6 core protocols have to be adapted to overcome 898 certain challenging aspects of vehicular networking. Since the 899 vehicles are likely to be moving at great speed, protocol exchanges 900 need to be completed in a time relatively short compared to the 901 lifetime of a link between a vehicle and an IP-RSU, or between two 902 vehicles. 904 Note that if two vehicles are moving in the opposite directions in a 905 roadway, the relative speed of this case is two times the relative 906 speed of a vehicle passing through an RSU. The time constraint of a 907 wireless link between two nodes needs to be considered because it may 908 affect the lifetime of a session involving the link. 910 The lifetime of a session varies depending on the session's type such 911 as a web surfing, voice call over IP, and DNS query. Regardless of a 912 session's type, to guide all the IPv6 packets to their destination 913 host, IP mobility should be supported for the session. 915 Thus, the time constraint of a wireless link has a major impact on 916 IPv6 Neighbor Discovery (ND). Mobility Management (MM) is also 917 vulnerable to disconnections that occur before the completion of 918 identity verification and tunnel management. This is especially true 919 given the unreliable nature of wireless communication. This section 920 presents key topics such as neighbor discovery and mobility 921 management. 923 5.1. Neighbor Discovery 925 IPv6 ND [RFC4861][RFC4862] is a core part of the IPv6 protocol suite. 926 IPv6 ND is designed for point-to-point links and transit links (e.g., 927 Ethernet). It assumes the efficient and reliable support of 928 multicast and unicast from the link layer for various network 929 operations such as MAC Address Resolution (AR), Duplicate Address 930 Detection (DAD), and Neighbor Unreachability Detection (NUD). 932 Vehicles move quickly within the communication coverage of any 933 particular vehicle or IP-RSU. Before the vehicles can exchange 934 application messages with each other, they need to be configured with 935 a link-local IPv6 address or a global IPv6 address, and run IPv6 ND. 937 The requirements for IPv6 ND for vehicular networks are efficient DAD 938 and NUD operations. An efficient DAD is required to reduce the 939 overhead of the DAD packets during a vehicle's travel in a road 940 network, which guaranteeing the uniqueness of a vehicle's global IPv6 941 address. An efficient NUD is required to reduce the overhead of the 942 NUD packets during a vehicle's travel in a road network, which 943 guaranteeing the accurate neighborhood information of a vehicle in 944 terms of adjacent vehicles and RSUs. 946 The legacy DAD assumes that a node with an IPv6 address can reach any 947 other node with the scope of its address at the time it claims its 948 address, and can hear any future claim for that address by another 949 party within the scope of its address for the duration of the address 950 ownership. However, the partitioning and merging of VANETs makes 951 this assumption frequently invalid in vehicular networks. The 952 merging and partitioning of VANETs frequently occurs in vehicular 953 networks. This merging and partitioning should be considered for the 954 IPv6 ND such as IPv6 Stateless Address Autoconfiguration (SLAAC) 955 [RFC4862]. Due to the merging of VANETs, two IPv6 addresses may 956 conflict with each other though they were unique before the merging. 957 Also, the partitioning of a VANET may make vehicles with the same 958 prefix be physically unreachable. Also, SLAAC needs to prevent IPv6 959 address duplication due to the merging of VANETs. According to the 960 merging and partitioning, a destination vehicle (as an IPv6 host) 961 needs to be distinguished as either an on-link host or an off-link 962 host even though the source vehicle uses the same prefix as the 963 destination vehicle. 965 To efficiently prevent IPv6 address duplication due to the VANET 966 partitioning and merging from happening in vehicular networks, the 967 vehicular networks need to support a vehicular-network-wide DAD by 968 defining a scope that is compatible with the legacy DAD. In this 969 case, two vehicles can communicate with each other when there exists 970 a communication path over VANET or a combination of VANETs and IP- 971 RSUs, as shown in Figure 1. By using the vehicular-network-wide DAD, 972 vehicles can assure that their IPv6 addresses are unique in the 973 vehicular network whenever they are connected to the vehicular 974 infrastructure or become disconnected from it in the form of VANET. 976 ND time-related parameters such as router lifetime and Neighbor 977 Advertisement (NA) interval need to be adjusted for vehicle speed and 978 vehicle density. For example, the NA interval needs to be 979 dynamically adjusted according to a vehicle's speed so that the 980 vehicle can maintain its neighboring vehicles in a stable way, 981 considering the collision probability with the NA messages sent by 982 other vehicles. 984 For IPv6-based safety applications (e.g., context-aware navigation, 985 adaptive cruise control, and platooning) in vehicular networks, the 986 delay-bounded data delivery is critical. IPv6 ND needs to work to 987 support those IPv6-based safety applications efficiently. 989 Thus, in IPv6-based vehicular networking, IPv6 ND should have minimum 990 changes for the interoperability with the legacy IPv6 ND used in the 991 Internet, including the DAD and NUD operations. 993 5.1.1. Link Model 995 A prefix model for a vehicular network needs to facilitate the 996 communication between two vehicles with the same prefix regardless of 997 the vehicular network topology as long as there exist bidirectional 998 E2E paths between them in the vehicular network including VANETs and 999 IP-RSUs. This prefix model allows vehicles with the same prefix to 1000 communicate with each other via a combination of multihop V2V and 1001 multihop V2I with VANETs and IP-RSUs. Note that the OMNI link model 1002 supports these multihop V2V and V2I through an OMNI multilink service 1003 [OMNI-Interface]. 1005 IPv6 protocols work under certain assumptions for the link model that 1006 do not necessarily hold in a vehicular wireless link 1007 [VIP-WAVE][RFC5889]. For instance, some IPv6 protocols assume 1008 symmetry in the connectivity among neighboring interfaces [RFC6250]. 1009 However, radio interference and different levels of transmission 1010 power may cause asymmetric links to appear in vehicular wireless 1011 links. As a result, a new vehicular link model needs to consider the 1012 asymmetry of dynamically changing vehicular wireless links. 1014 There is a relationship between a link and a prefix, besides the 1015 different scopes that are expected from the link-local and global 1016 types of IPv6 addresses. In an IPv6 link, it is assumed that all 1017 interfaces which are configured with the same subnet prefix and with 1018 on-link bit set can communicate with each other on an IPv6 link. 1019 However, the vehicular link model needs to define the relationship 1020 between a link and a prefix, considering the dynamics of wireless 1021 links and the characteristics of VANET. 1023 A VANET can have a single link between each vehicle pair within 1024 wireless communication range, as shown in Figure 5. When two 1025 vehicles belong to the same VANET, but they are out of wireless 1026 communication range, they cannot communicate directly with each 1027 other. Suppose that a global-scope IPv6 prefix (or an IPv6 ULA 1028 prefix) is assigned to VANETs in vehicular networks. Even though two 1029 vehicles in the same VANET configure their IPv6 addresses with the 1030 same IPv6 prefix, they may not communicate with each other not in one 1031 hop in the same VANET because of the multihop network connectivity 1032 between them. Thus, in this case, the concept of an on-link IPv6 1033 prefix does not hold because two vehicles with the same on-link IPv6 1034 prefix cannot communicate directly with each other. Also, when two 1035 vehicles are located in two different VANETs with the same IPv6 1036 prefix, they cannot communicate with each other. When these two 1037 VANETs converge to one VANET, the two vehicles can communicate with 1038 each other in a multihop fashion, for example, when they are Vehicle1 1039 and Vehicle3, as shown in Figure 5. 1041 From the previous observation, a vehicular link model should consider 1042 the frequent partitioning and merging of VANETs due to vehicle 1043 mobility. Therefore, the vehicular link model needs to use an on- 1044 link prefix and off-link prefix according to the network topology of 1045 vehicles such as a one-hop reachable network and a multihop reachable 1046 network (or partitioned networks). If the vehicles with the same 1047 prefix are reachable from each other in one hop, the prefix should be 1048 on-link. On the other hand, if some of the vehicles with the same 1049 prefix are not reachable from each other in one hop due to either the 1050 multihop topology in the VANET or multiple partitions, the prefix 1051 should be off-link. 1053 The vehicular link model needs to support multihop routing in a 1054 connected VANET where the vehicles with the same global-scope IPv6 1055 prefix (or the same IPv6 ULA prefix) are connected in one hop or 1056 multiple hops. It also needs to support the multihop routing in 1057 multiple connected VANETs through infrastructure nodes (e.g., IP-RSU) 1058 where they are connected to the infrastructure. For example, in 1059 Figure 1, suppose that Vehicle1, Vehicle2, and Vehicle3 are 1060 configured with their IPv6 addresses based on the same global-scope 1061 IPv6 prefix. Vehicle1 and Vehicle3 can also communicate with each 1062 other via either multihop V2V or multihop V2I2V. When Vehicle1 and 1063 Vehicle3 are connected in a VANET, it will be more efficient for them 1064 to communicate with each other directly via VANET rather than 1065 indirectly via IP-RSUs. On the other hand, when Vehicle1 and 1066 Vehicle3 are far away from direct communication range in separate 1067 VANETs and under two different IP-RSUs, they can communicate with 1068 each other through the relay of IP-RSUs via V2I2V. Thus, two 1069 separate VANETs can merge into one network via IP-RSU(s). Also, 1070 newly arriving vehicles can merge two separate VANETs into one VANET 1071 if they can play the role of a relay node for those VANETs. 1073 Thus, in IPv6-based vehicular networking, the vehicular link model 1074 should have minimum changes for the interoperability with the legacy 1075 IPv6 link model in an efficient fashion to support the IPv6 DAD and 1076 NUD operations. 1078 5.1.2. MAC Address Pseudonym 1080 For the protection of drivers' privacy, a pseudonym of a MAC address 1081 of a vehicle's network interface should be used, so that the MAC 1082 address can be changed periodically. However, although such a 1083 pseudonym of a MAC address can protect to some extent the privacy of 1084 a vehicle, it may not be able to resist attacks on vehicle 1085 identification by other fingerprint information, for example, the 1086 scrambler seed embedded in IEEE 802.11-OCB frames [Scrambler-Attack]. 1087 The pseudonym of a MAC address affects an IPv6 address based on the 1088 MAC address, and a transport-layer (e.g., TCP and SCTP) session with 1089 an IPv6 address pair. However, the pseudonym handling is not 1090 implemented and tested yet for applications on IP-based vehicular 1091 networking. 1093 In the ETSI standards, for the sake of security and privacy, an ITS 1094 station (e.g., vehicle) can use pseudonyms for its network interface 1095 identities (e.g., MAC address) and the corresponding IPv6 addresses 1096 [Identity-Management]. Whenever the network interface identifier 1097 changes, the IPv6 address based on the network interface identifier 1098 needs to be updated, and the uniqueness of the address needs to be 1099 checked through the DAD procedure. For vehicular networks with high 1100 mobility and density, this DAD needs to be performed efficiently with 1101 minimum overhead so that the vehicles can exchange application 1102 messages (e.g., collision avoidance and accident notification) with 1103 each other with a short interval (e.g., 0.5 second) 1104 [NHTSA-ACAS-Report]. 1106 5.1.3. Routing 1108 For multihop V2V communications in either a VANET or VANETs via IP- 1109 RSUs, a vehicular ad hoc routing protocol (e.g., AODV or OLSRv2) may 1110 be required to support both unicast and multicast in the links of the 1111 subnet with the same IPv6 prefix. However, it will be costly to run 1112 both vehicular ND and a vehicular ad hoc routing protocol in terms of 1113 control traffic overhead [ID-Multicast-Problems]. 1115 A routing protocol for a VANET may cause redundant wireless frames in 1116 the air to check the neighborhood of each vehicle and compute the 1117 routing information in a VANET with a dynamic network topology 1118 because the IPv6 ND is used to check the neighborhood of each 1119 vehicle. Thus, the vehicular routing needs to take advantage of the 1120 IPv6 ND to minimize its control overhead. 1122 5.2. Mobility Management 1124 The seamless connectivity and timely data exchange between two end 1125 points requires efficient mobility management including location 1126 management and handover. Most vehicles are equipped with a GPS 1127 receiver as part of a dedicated navigation system or a corresponding 1128 smartphone App. Note that the GPS receiver may not provide vehicles 1129 with accurate location information in adverse environments such as a 1130 building area or a tunnel. The location precision can be improved 1131 with assistance of the IP-RSUs or a cellular system with a GPS 1132 receiver for location information. 1134 With a GPS navigator, efficient mobility management can be performed 1135 with the help of vehicles periodically reporting their current 1136 position and trajectory (i.e., navigation path) to the vehicular 1137 infrastructure (having IP-RSUs and an MA in TCC). This vehicular 1138 infrastructure can predict the future positions of the vehicles from 1139 their mobility information (i.e., the current position, speed, 1140 direction, and trajectory) for efficient mobility management (e.g., 1141 proactive handover). For a better proactive handover, link-layer 1142 parameters, such as the signal strength of a link-layer frame (e.g., 1143 Received Channel Power Indicator (RCPI) [VIP-WAVE]), can be used to 1144 determine the moment of a handover between IP-RSUs along with 1145 mobility information. 1147 By predicting a vehicle's mobility, the vehicular infrastructure 1148 needs to better support IP-RSUs to perform efficient SLAAC, data 1149 forwarding, horizontal handover (i.e., handover in wireless links 1150 using a homogeneous radio technology), and vertical handover (i.e., 1151 handover in wireless links using heterogeneous radio technologies) in 1152 advance along with the movement of the vehicle. 1154 For example, as shown in Figure 1, when a vehicle (e.g., Vehicle2) is 1155 moving from the coverage of an IP-RSU (e.g., IP-RSU1) into the 1156 coverage of another IP-RSU (e.g., IP-RSU2) belonging to a different 1157 subnet, the IP-RSUs can proactively support the IPv6 mobility of the 1158 vehicle, while performing the SLAAC, data forwarding, and handover 1159 for the sake of the vehicle. 1161 For a mobility management scheme in a shared link, where the wireless 1162 subnets of multiple IP-RSUs share the same prefix, an efficient 1163 vehicular-network-wide DAD is required. If DHCPv6 is used to assign 1164 a unique IPv6 address to each vehicle in this shared link, the DAD is 1165 not required. On the other hand, for a mobility management scheme 1166 with a unique prefix per mobile node (e.g., PMIPv6 [RFC5213] and OMNI 1167 [OMNI-Interface]), DAD is not required because the IPv6 address of a 1168 vehicle's external wireless interface is guaranteed to be unique. 1169 There is a tradeoff between the prefix usage efficiency and DAD 1170 overhead. Thus, the IPv6 address autoconfiguration for vehicular 1171 networks needs to consider this tradeoff to support efficient 1172 mobility management. 1174 Therefore, for the proactive and seamless IPv6 mobility of vehicles, 1175 the vehicular infrastructure (including IP-RSUs and MA) needs to 1176 efficiently perform the mobility management of the vehicles with 1177 their mobility information and link-layer information. Also, in 1178 IPv6-based vehicular networking, IPv6 mobility management should have 1179 minimum changes for the interoperability with the legacy IPv6 1180 mobility management schemes such as PMIPv6, DMM, LISP, and AERO. 1182 6. Security Considerations 1184 This section discusses security and privacy for IPv6-based vehicular 1185 networking. Security and privacy are key components of IPv6-based 1186 vehicular networking along with neighbor discovery and mobility 1187 management. 1189 Security and privacy are paramount in V2I, V2V, and V2X networking. 1190 Vehicles and infrastructure must be authenticated in order to 1191 participate in vehicular networking. Also, in-vehicle devices (e.g., 1192 ECU) and a driver/passenger's mobile devices (e.g., smartphone and 1193 tablet PC) in a vehicle need to communicate with other in-vehicle 1194 devices and another driver/passenger's mobile devices in another 1195 vehicle, or other servers behind an IP-RSU in a secure way. Even 1196 though a vehicle is perfectly authenticated and legitimate, it may be 1197 hacked for running malicious applications to track and collect its 1198 and other vehicles' information. In this case, an attack mitigation 1199 process may be required to reduce the aftermath of malicious 1200 behaviors. 1202 Strong security measures shall protect vehicles roaming in road 1203 networks from the attacks of malicious nodes, which are controlled by 1204 hackers. For safe driving applications (e.g., context-aware 1205 navigation, cooperative adaptive cruise control, and platooning), as 1206 explained in Section 3.1, the cooperative action among vehicles is 1207 assumed. Malicious nodes may disseminate wrong driving information 1208 (e.g., location, speed, and direction) for disturbing safe driving. 1209 For example, a Sybil attack, which tries to confuse a vehicle with 1210 multiple false identities, may disturb a vehicle from taking a safe 1211 maneuver. 1213 Even though vehicles can be authenticated with valid certificates by 1214 an authentication server in the vehicular cloud, the authenticated 1215 vehicles may harm other vehicles, so their communication activities 1216 need to be logged in either a central way through a logging server 1217 (e.g., TCC) in the vehicular cloud or a distributed way (e.g., 1218 blockchain [Bitcoin]) along with other vehicles or infrastructure. 1219 For the non-repudiation of the harmful activities of malicious nodes, 1220 a blockchain technology can be used [Bitcoin]. Each message from a 1221 vehicle can be treated as a transaction and the neighboring vehicles 1222 can play the role of peers in a consensus method of a blockchain such 1223 as PoW and PoS [Bitcoin][Vehicular-BlockChain]. 1225 To identify malicious vehicles among vehicles, an authentication 1226 method is required. A Vehicle Identification Number (VIN) and a user 1227 certificate (e.g., X.509 certificate [RFC5280]) along with an in- 1228 vehicle device's identifier generation can be used to efficiently 1229 authenticate a vehicle or its driver (having a user certificate) 1230 through a road infrastructure node (e.g., IP-RSU) connected to an 1231 authentication server in the vehicular cloud. This authentication 1232 can be used to identify the vehicle that will communicate with an 1233 infrastructure node or another vehicle. In the case where a vehicle 1234 has an internal network (called Moving Network) and elements in the 1235 network (e.g., in-vehicle devices and a user's mobile devices), as 1236 shown in Figure 3, the elements in the network need to be 1237 authenticated individually for safe authentication. Also, Transport 1238 Layer Security (TLS) certificates [RFC8446][RFC5280] can be used for 1239 an element's authentication to allow secure E2E vehicular 1240 communications between an element in a vehicle and another element in 1241 a server in a vehicular cloud, or between an element in a vehicle and 1242 another element in another vehicle. 1244 For secure V2I communication, a secure channel (e.g., IPsec) between 1245 a mobile router (i.e., IP-OBU) in a vehicle and a fixed router (i.e., 1246 IP-RSU) in an EN needs to be established, as shown in Figure 3 1247 [RFC4301][RFC4302][RFC4303][RFC4308][RFC7296]. Also, for secure V2V 1248 communication, a secure channel (e.g., IPsec) between a mobile router 1249 (i.e., IP-OBU) in a vehicle and a mobile router (i.e., IP-OBU) in 1250 another vehicle needs to be established, as shown in Figure 4. For 1251 secure communication, an element in a vehicle (e.g., an in-vehicle 1252 device and a driver/passenger's mobile device) needs to establish a 1253 secure connection (e.g., TLS) with another element in another vehicle 1254 or another element in a vehicular cloud (e.g., a server). Even 1255 though IEEE 1609.2 [WAVE-1609.2] specifies security services for 1256 applications and management messages. This WAVE specification is 1257 optional, so if WAVE does not support the security of a WAVE frame, 1258 either the network layer or the transport layer needs to support 1259 security services for the WAVE frames. 1261 For the setup of a secure channel over IPsec or TLS, the multihop V2I 1262 communications over DSRC is required in a highway for the 1263 authentication by involving multiple intermediate vehicles as relay 1264 nodes toward an IP-RSU connected to an authentication server in the 1265 vehicular cloud. The V2I communications over 5G V2X (or LTE V2X) is 1266 required to allow a vehicle to communicate directly with a gNodeB (or 1267 eNodeB) connected to an authentication server in the vehicular cloud. 1269 To prevent an adversary from tracking a vehicle with its MAC address 1270 or IPv6 address, especially for a long-living transport-layer session 1271 (e.g., voice call over IP and video streaming service), a MAC address 1272 pseudonym needs to be provided to each vehicle; that is, each vehicle 1273 periodically updates its MAC address and its IPv6 address needs to be 1274 updated accordingly by the MAC address change [RFC4086][RFC4941]. 1275 Such an update of the MAC and IPv6 addresses should not interrupt the 1276 E2E communications between two vehicles (or between a vehicle and an 1277 IP-RSU) for a long-living transport-layer session. However, if this 1278 pseudonym is performed without strong E2E confidentiality (using 1279 either IPsec or TLS), there will be no privacy benefit from changing 1280 MAC and IPv6 addresses, because an adversary can observe the change 1281 of the MAC and IPv6 addresses and track the vehicle with those 1282 addresses. Thus, the MAC address pseudonym and the IPv6 address 1283 update should be performed with strong E2E confidentiality. 1285 For the IPv6 ND, the DAD is required to ensure the uniqueness of the 1286 IPv6 address of a vehicle's wireless interface. This DAD can be used 1287 as a flooding attack that uses the DAD-related ND packets 1288 disseminated over the VANET or vehicular networks. Thus, the 1289 vehicles and IP-RSUs need to filter out suspicious ND traffic in 1290 advance. 1292 For mobility management, a malicious vehicle can construct multiple 1293 virtual bogus vehicles, and register them with IP-RSUs and MA. This 1294 registration makes the IP-RSUs and MA waste their resources. The IP- 1295 RSUs and MA need to determine whether a vehicle is genuine or bogus 1296 in mobility management. Also, the confidentiality of control packets 1297 and data packets among IP-RSUs and MA, the E2E paths (e.g., tunnels) 1298 need to be protected by secure communication channels. In addition, 1299 to prevent bogus IP-RSUs and MA from interfering with the IPv6 1300 mobility of vehicles, mutual authentication among them needs to be 1301 performed by certificates (e.g., TLS certificate). 1303 7. Informative References 1305 [Automotive-Sensing] 1306 Choi, J., Va, V., Gonzalez-Prelcic, N., Daniels, R., R. 1307 Bhat, C., and R. W. Heath, "Millimeter-Wave Vehicular 1308 Communication to Support Massive Automotive Sensing", 1309 IEEE Communications Magazine, December 2016. 1311 [Bitcoin] Nakamoto, S., "Bitcoin: A Peer-to-Peer Electronic Cash 1312 System", URL: https://bitcoin.org/bitcoin.pdf, May 2009. 1314 [CA-Cruise-Control] 1315 California Partners for Advanced Transportation Technology 1316 (PATH), "Cooperative Adaptive Cruise Control", [Online] 1317 Available: 1318 http://www.path.berkeley.edu/research/automated-and- 1319 connected-vehicles/cooperative-adaptive-cruise-control, 1320 2017. 1322 [CASD] Shen, Y., Jeong, J., Oh, T., and S. Son, "CASD: A 1323 Framework of Context-Awareness Safety Driving in Vehicular 1324 Networks", International Workshop on Device Centric Cloud 1325 (DC2), March 2016. 1327 [DMM-FPC] Matsushima, S., Bertz, L., Liebsch, M., Gundavelli, S., 1328 Moses, D., and C. Perkins, "Protocol for Forwarding Policy 1329 Configuration (FPC) in DMM", draft-ietf-dmm-fpc-cpdp-13 1330 (work in progress), March 2020. 1332 [DSRC] ASTM International, "Standard Specification for 1333 Telecommunications and Information Exchange Between 1334 Roadside and Vehicle Systems - 5 GHz Band Dedicated Short 1335 Range Communications (DSRC) Medium Access Control (MAC) 1336 and Physical Layer (PHY) Specifications", 1337 ASTM E2213-03(2010), October 2010. 1339 [EU-2008-671-EC] 1340 European Union, "Commission Decision of 5 August 2008 on 1341 the Harmonised Use of Radio Spectrum in the 5875 - 5905 1342 MHz Frequency Band for Safety-related Applications of 1343 Intelligent Transport Systems (ITS)", EU 2008/671/EC, 1344 August 2008. 1346 [FirstNet] 1347 U.S. National Telecommunications and Information 1348 Administration (NTIA), "First Responder Network Authority 1349 (FirstNet)", [Online] 1350 Available: https://www.firstnet.gov/, 2012. 1352 [FirstNet-Report] 1353 First Responder Network Authority, "FY 2017: ANNUAL REPORT 1354 TO CONGRESS, Advancing Public Safety Broadband 1355 Communications", FirstNet FY 2017, December 2017. 1357 [Fuel-Efficient] 1358 van de Hoef, S., H. Johansson, K., and D. V. Dimarogonas, 1359 "Fuel-Efficient En Route Formation of Truck Platoons", 1360 IEEE Transactions on Intelligent Transportation Systems, 1361 January 2018. 1363 [ID-Multicast-Problems] 1364 Perkins, C., McBride, M., Stanley, D., Kumari, W., and JC. 1365 Zuniga, "Multicast Considerations over IEEE 802 Wireless 1366 Media", draft-ietf-mboned-ieee802-mcast-problems-11 (work 1367 in progress), December 2019. 1369 [Identity-Management] 1370 Wetterwald, M., Hrizi, F., and P. Cataldi, "Cross-layer 1371 Identities Management in ITS Stations", The 10th 1372 International Conference on ITS Telecommunications, 1373 November 2010. 1375 [IEEE-802.11-OCB] 1376 "Part 11: Wireless LAN Medium Access Control (MAC) and 1377 Physical Layer (PHY) Specifications", IEEE Std 1378 802.11-2016, December 2016. 1380 [IEEE-802.11p] 1381 "Part 11: Wireless LAN Medium Access Control (MAC) and 1382 Physical Layer (PHY) Specifications - Amendment 6: 1383 Wireless Access in Vehicular Environments", IEEE Std 1384 802.11p-2010, June 2010. 1386 [In-Car-Network] 1387 Lim, H., Volker, L., and D. Herrscher, "Challenges in a 1388 Future IP/Ethernet-based In-Car Network for Real-Time 1389 Applications", ACM/EDAC/IEEE Design Automation Conference 1390 (DAC), June 2011. 1392 [ISO-ITS-IPv6] 1393 ISO/TC 204, "Intelligent Transport Systems - 1394 Communications Access for Land Mobiles (CALM) - IPv6 1395 Networking", ISO 21210:2012, June 2012. 1397 [ISO-ITS-IPv6-AMD1] 1398 ISO/TC 204, "Intelligent Transport Systems - 1399 Communications Access for Land Mobiles (CALM) - IPv6 1400 Networking - Amendment 1", ISO 21210:2012/AMD 1:2017, 1401 September 2017. 1403 [NHTSA-ACAS-Report] 1404 National Highway Traffic Safety Administration (NHTSA), 1405 "Final Report of Automotive Collision Avoidance Systems 1406 (ACAS) Program", DOT HS 809 080, August 2000. 1408 [OMNI-Interface] 1409 Templin, F. and A. Whyman, "Transmission of IPv6 Packets 1410 over Overlay Multilink Network (OMNI) Interfaces", draft- 1411 templin-6man-omni-interface-24 (work in progress), June 1412 2020. 1414 [RFC3561] Perkins, C., Belding-Royer, E., and S. Das, "Ad hoc On- 1415 Demand Distance Vector (AODV) Routing", RFC 3561, July 1416 2003. 1418 [RFC3753] Manner, J. and M. Kojo, "Mobility Related Terminology", 1419 RFC 3753, June 2004. 1421 [RFC3849] Huston, G., Lord, A., and P. Smith, "IPv6 Address Prefix 1422 Reserved for Documentation", RFC 3849, July 2004. 1424 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 1425 "Randomness Requirements for Security", RFC 4086, June 1426 2005. 1428 [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast 1429 Addresses", RFC 4193, October 2005. 1431 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 1432 Internet Protocol", RFC 4301, December 2005. 1434 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, December 1435 2005. 1437 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 1438 RFC 4303, December 2005. 1440 [RFC4308] Hoffman, P., "Cryptographic Suites for IPsec", RFC 4308, 1441 December 2005. 1443 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 1444 "Neighbor Discovery for IP Version 6 (IPv6)", RFC 4861, 1445 September 2007. 1447 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 1448 Address Autoconfiguration", RFC 4862, September 2007. 1450 [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy 1451 Extensions for Stateless Address Autoconfiguration in 1452 IPv6", RFC 4941, September 2007. 1454 [RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V., 1455 Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", 1456 RFC 5213, August 2008. 1458 [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., 1459 Housley, R., and W. Polk, "Internet X.509 Public Key 1460 Infrastructure Certificate and Certificate Revocation List 1461 (CRL) Profile", RFC 5280, May 2008. 1463 [RFC5415] Calhoun, P., Montemurro, M., and D. Stanley, "Control And 1464 Provisioning of Wireless Access Points (CAPWAP) Protocol 1465 Specification", RFC 5415, March 2009. 1467 [RFC5889] Baccelli, E. and M. Townsley, "IP Addressing Model in Ad 1468 Hoc Networks", RFC 5889, September 2010. 1470 [RFC6250] Thaler, D., "Evolution of the IP Model", RFC 6250, May 1471 2011. 1473 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 1474 Support in IPv6", RFC 6275, July 2011. 1476 [RFC6550] Winter, T., Thubert, P., Brandt, A., Hui, J., Kelsey, R., 1477 Levis, P., Pister, K., Struik, R., Vasseur, JP., and R. 1478 Alexander, "RPL: IPv6 Routing Protocol for Low-Power and 1479 Lossy Networks", RFC 6550, March 2012. 1481 [RFC6706] Templin, F., "Asymmetric Extended Route Optimization 1482 (AERO)", RFC 6706, August 2012. 1484 [RFC6775] Shelby, Z., Chakrabarti, S., Nordmark, E., and C. Bormann, 1485 "Neighbor Discovery Optimization for IPv6 over Low-Power 1486 Wireless Personal Area Networks (6LoWPANs)", RFC 6775, 1487 November 2012. 1489 [RFC6830] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The 1490 Locator/ID Separation Protocol (LISP)", RFC 6830, January 1491 2013. 1493 [RFC7149] Boucadair, M. and C. Jacquenet, "Software-Defined 1494 Networking: A Perspective from within a Service Provider 1495 Environment", RFC 7149, March 2014. 1497 [RFC7181] Clausen, T., Dearlove, C., Jacquet, P., and U. Herberg, 1498 "The Optimized Link State Routing Protocol Version 2", 1499 RFC 7181, April 2014. 1501 [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. 1502 Kivinen, "Internet Key Exchange Protocol Version 2 1503 (IKEv2)", RFC 7296, October 2014. 1505 [RFC7333] Chan, H., Liu, D., Seite, P., Yokota, H., and J. Korhonen, 1506 "Requirements for Distributed Mobility Management", 1507 RFC 7333, August 2014. 1509 [RFC7429] Liu, D., Zuniga, JC., Seite, P., Chan, H., and CJ. 1510 Bernardos, "Distributed Mobility Management: Current 1511 Practices and Gap Analysis", RFC 7429, January 2015. 1513 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1514 (IPv6) Specification", RFC 8200, July 2017. 1516 [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol 1517 Version 1.3", RFC 8446, August 2018. 1519 [RFC8691] Benamar, N., Haerri, J., Lee, J., and T. Ernst, "Basic 1520 Support for IPv6 Networks Operating Outside the Context of 1521 a Basic Service Set over IEEE Std 802.11", RFC 8691, 1522 December 2019. 1524 [SAINT] Jeong, J., Jeong, H., Lee, E., Oh, T., and D. Du, "SAINT: 1525 Self-Adaptive Interactive Navigation Tool for Cloud-Based 1526 Vehicular Traffic Optimization", IEEE Transactions on 1527 Vehicular Technology, Vol. 65, No. 6, June 2016. 1529 [SAINTplus] 1530 Shen, Y., Lee, J., Jeong, H., Jeong, J., Lee, E., and D. 1531 Du, "SAINT+: Self-Adaptive Interactive Navigation Tool+ 1532 for Emergency Service Delivery Optimization", 1533 IEEE Transactions on Intelligent Transportation Systems, 1534 June 2017. 1536 [SANA] Hwang, T. and J. Jeong, "SANA: Safety-Aware Navigation 1537 Application for Pedestrian Protection in Vehicular 1538 Networks", Springer Lecture Notes in Computer Science 1539 (LNCS), Vol. 9502, December 2015. 1541 [Scrambler-Attack] 1542 Bloessl, B., Sommer, C., Dressier, F., and D. Eckhoff, 1543 "The Scrambler Attack: A Robust Physical Layer Attack on 1544 Location Privacy in Vehicular Networks", IEEE 2015 1545 International Conference on Computing, Networking and 1546 Communications (ICNC), February 2015. 1548 [SignalGuru] 1549 Koukoumidis, E., Peh, L., and M. Martonosi, "SignalGuru: 1550 Leveraging Mobile Phones for Collaborative Traffic Signal 1551 Schedule Advisory", ACM MobiSys, June 2011. 1553 [TR-22.886-3GPP] 1554 3GPP, "Study on Enhancement of 3GPP Support for 5G V2X 1555 Services", 3GPP TR 22.886/Version 16.2.0, December 2018. 1557 [Truck-Platooning] 1558 California Partners for Advanced Transportation Technology 1559 (PATH), "Automated Truck Platooning", [Online] Available: 1560 http://www.path.berkeley.edu/research/automated-and- 1561 connected-vehicles/truck-platooning, 2017. 1563 [TS-23.285-3GPP] 1564 3GPP, "Architecture Enhancements for V2X Services", 3GPP 1565 TS 23.285/Version 16.2.0, December 2019. 1567 [TS-23.287-3GPP] 1568 3GPP, "Architecture Enhancements for 5G System (5GS) to 1569 Support Vehicle-to-Everything (V2X) Services", 3GPP 1570 TS 23.287/Version 16.2.0, March 2020. 1572 [Vehicular-BlockChain] 1573 Dorri, A., Steger, M., Kanhere, S., and R. Jurdak, 1574 "BlockChain: A Distributed Solution to Automotive Security 1575 and Privacy", IEEE Communications Magazine, Vol. 55, No. 1576 12, December 2017. 1578 [VIP-WAVE] 1579 Cespedes, S., Lu, N., and X. Shen, "VIP-WAVE: On the 1580 Feasibility of IP Communications in 802.11p Vehicular 1581 Networks", IEEE Transactions on Intelligent Transportation 1582 Systems, vol. 14, no. 1, March 2013. 1584 [WAVE-1609.0] 1585 IEEE 1609 Working Group, "IEEE Guide for Wireless Access 1586 in Vehicular Environments (WAVE) - Architecture", IEEE Std 1587 1609.0-2013, March 2014. 1589 [WAVE-1609.2] 1590 IEEE 1609 Working Group, "IEEE Standard for Wireless 1591 Access in Vehicular Environments - Security Services for 1592 Applications and Management Messages", IEEE Std 1593 1609.2-2016, March 2016. 1595 [WAVE-1609.3] 1596 IEEE 1609 Working Group, "IEEE Standard for Wireless 1597 Access in Vehicular Environments (WAVE) - Networking 1598 Services", IEEE Std 1609.3-2016, April 2016. 1600 [WAVE-1609.4] 1601 IEEE 1609 Working Group, "IEEE Standard for Wireless 1602 Access in Vehicular Environments (WAVE) - Multi-Channel 1603 Operation", IEEE Std 1609.4-2016, March 2016. 1605 Appendix A. Changes from draft-ietf-ipwave-vehicular-networking-14 1607 The following changes are made from draft-ietf-ipwave-vehicular- 1608 networking-14: 1610 o This version is revised based on the comments from eight 1611 reviewers: Nancy Cam-Winget (Cisco), Fred L. Templin (The Boeing 1612 Company), Jung-Soo Park (ETRI), Zeungil (Ben) Kim (Hyundai 1613 Motors), Kyoungjae Sun (Soongsil University), Zhiwei Yan (CNNIC), 1614 Yong-Joon Joe (LSware), and Peter E. Yee (Akayla). 1616 Appendix B. Acknowledgments 1618 This work was supported by Institute of Information & Communications 1619 Technology Planning & Evaluation (IITP) grant funded by the Korea 1620 MSIT (Ministry of Science and ICT) (R-20160222-002755, Cloud based 1621 Security Intelligence Technology Development for the Customized 1622 Security Service Provisioning). 1624 This work was supported in part by the MSIT (Ministry of Science and 1625 ICT), Korea, under the ITRC (Information Technology Research Center) 1626 support program (IITP-2019-2017-0-01633) supervised by the IITP 1627 (Institute for Information & communications Technology Promotion). 1629 This work was supported in part by the French research project 1630 DataTweet (ANR-13-INFR-0008) and in part by the HIGHTS project funded 1631 by the European Commission I (636537-H2020). 1633 Appendix C. Contributors 1635 This document is a group work of IPWAVE working group, greatly 1636 benefiting from inputs and texts by Rex Buddenberg (Naval 1637 Postgraduate School), Thierry Ernst (YoGoKo), Bokor Laszlo (Budapest 1638 University of Technology and Economics), Jose Santa Lozanoi 1639 (Universidad of Murcia), Richard Roy (MIT), Francois Simon (Pilot), 1640 Sri Gundavelli (Cisco), Erik Nordmark, Dirk von Hugo (Deutsche 1641 Telekom), Pascal Thubert (Cisco), Carlos Bernardos (UC3M), Russ 1642 Housley (Vigil Security), and Suresh Krishnan (Kaloom). The authors 1643 sincerely appreciate their contributions. 1645 The following are co-authors of this document: 1647 Nabil Benamar 1648 Department of Computer Sciences 1649 High School of Technology of Meknes 1650 Moulay Ismail University 1651 Morocco 1652 Phone: +212 6 70 83 22 36 1653 EMail: benamar73@gmail.com 1655 Sandra Cespedes 1656 NIC Chile Research Labs 1657 Universidad de Chile 1658 Av. Blanco Encalada 1975 1659 Santiago 1660 Chile 1662 Phone: +56 2 29784093 1663 EMail: scespede@niclabs.cl 1665 Jerome Haerri 1666 Communication Systems Department 1667 EURECOM 1668 Sophia-Antipolis 1669 France 1671 Phone: +33 4 93 00 81 34 1672 EMail: jerome.haerri@eurecom.fr 1674 Dapeng Liu 1675 Alibaba 1676 Beijing, Beijing 100022 1677 China 1679 Phone: +86 13911788933 1680 EMail: max.ldp@alibaba-inc.com 1682 Tae (Tom) Oh 1683 Department of Information Sciences and Technologies 1684 Rochester Institute of Technology 1685 One Lomb Memorial Drive 1686 Rochester, NY 14623-5603 1687 USA 1689 Phone: +1 585 475 7642 1690 EMail: Tom.Oh@rit.edu 1692 Charles E. Perkins 1693 Futurewei Inc. 1695 2330 Central Expressway 1696 Santa Clara, CA 95050 1697 USA 1699 Phone: +1 408 330 4586 1700 EMail: charliep@computer.org 1702 Alexandre Petrescu 1703 CEA, LIST 1704 CEA Saclay 1705 Gif-sur-Yvette, Ile-de-France 91190 1706 France 1708 Phone: +33169089223 1709 EMail: Alexandre.Petrescu@cea.fr 1711 Yiwen Chris Shen 1712 Department of Computer Science & Engineering 1713 Sungkyunkwan University 1714 2066 Seobu-Ro, Jangan-Gu 1715 Suwon, Gyeonggi-Do 16419 1716 Republic of Korea 1718 Phone: +82 31 299 4106 1719 Fax: +82 31 290 7996 1720 EMail: chrisshen@skku.edu 1721 URI: http://iotlab.skku.edu/people-chris-shen.php 1723 Michelle Wetterwald 1724 FBConsulting 1725 21, Route de Luxembourg 1726 Wasserbillig, Luxembourg L-6633 1727 Luxembourg 1729 EMail: Michelle.Wetterwald@gmail.com 1731 Author's Address 1732 Jaehoon Paul Jeong (editor) 1733 Department of Computer Science and Engineering 1734 Sungkyunkwan University 1735 2066 Seobu-Ro, Jangan-Gu 1736 Suwon, Gyeonggi-Do 16419 1737 Republic of Korea 1739 Phone: +82 31 299 4957 1740 Fax: +82 31 290 7996 1741 EMail: pauljeong@skku.edu 1742 URI: http://iotlab.skku.edu/people-jaehoon-jeong.php