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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group A. Petrescu 3 Internet-Draft CEA, LIST 4 Intended status: Standards Track N. Benamar 5 Expires: August 8, 2018 Moulay Ismail University 6 J. Haerri 7 Eurecom 8 J. Lee 9 Sangmyung University 10 T. Ernst 11 YoGoKo 12 February 4, 2018 14 Transmission of IPv6 Packets over IEEE 802.11 Networks operating in mode 15 Outside the Context of a Basic Service Set (IPv6-over-80211-OCB) 16 draft-ietf-ipwave-ipv6-over-80211ocb-13.txt 18 Abstract 20 In order to transmit IPv6 packets on IEEE 802.11 networks running 21 outside the context of a basic service set (OCB, earlier "802.11p") 22 there is a need to define a few parameters such as the supported 23 Maximum Transmission Unit size on the 802.11-OCB link, the header 24 format preceding the IPv6 header, the Type value within it, and 25 others. This document describes these parameters for IPv6 and IEEE 26 802.11-OCB networks; it portrays the layering of IPv6 on 802.11-OCB 27 similarly to other known 802.11 and Ethernet layers - by using an 28 Ethernet Adaptation Layer. 30 Status of This Memo 32 This Internet-Draft is submitted in full conformance with the 33 provisions of BCP 78 and BCP 79. 35 Internet-Drafts are working documents of the Internet Engineering 36 Task Force (IETF). Note that other groups may also distribute 37 working documents as Internet-Drafts. The list of current Internet- 38 Drafts is at https://datatracker.ietf.org/drafts/current/. 40 Internet-Drafts are draft documents valid for a maximum of six months 41 and may be updated, replaced, or obsoleted by other documents at any 42 time. It is inappropriate to use Internet-Drafts as reference 43 material or to cite them other than as "work in progress." 45 This Internet-Draft will expire on August 8, 2018. 47 Copyright Notice 49 Copyright (c) 2018 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (https://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with respect 57 to this document. Code Components extracted from this document must 58 include Simplified BSD License text as described in Section 4.e of 59 the Trust Legal Provisions and are provided without warranty as 60 described in the Simplified BSD License. 62 Table of Contents 64 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 65 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 66 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 5 67 4. IPv6 over 802.11-OCB . . . . . . . . . . . . . . . . . . . . 5 68 4.1. Maximum Transmission Unit (MTU) . . . . . . . . . . . . . 5 69 4.2. Frame Format . . . . . . . . . . . . . . . . . . . . . . 6 70 4.2.1. Ethernet Adaptation Layer . . . . . . . . . . . . . . 6 71 4.3. Link-Local Addresses . . . . . . . . . . . . . . . . . . 8 72 4.4. Address Mapping . . . . . . . . . . . . . . . . . . . . . 9 73 4.4.1. Address Mapping -- Unicast . . . . . . . . . . . . . 9 74 4.4.2. Address Mapping -- Multicast . . . . . . . . . . . . 9 75 4.5. Stateless Autoconfiguration . . . . . . . . . . . . . . . 9 76 4.6. Subnet Structure . . . . . . . . . . . . . . . . . . . . 10 77 5. Security Considerations . . . . . . . . . . . . . . . . . . . 10 78 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 79 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 11 80 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 81 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 82 9.1. Normative References . . . . . . . . . . . . . . . . . . 12 83 9.2. Informative References . . . . . . . . . . . . . . . . . 15 84 Appendix A. ChangeLog . . . . . . . . . . . . . . . . . . . . . 16 85 Appendix B. 802.11p . . . . . . . . . . . . . . . . . . . . . . 23 86 Appendix C. Aspects introduced by the OCB mode to 802.11 . . . . 23 87 Appendix D. Changes Needed on a software driver 802.11a to 88 become a 802.11-OCB driver . . . 27 89 Appendix E. EtherType Protocol Discrimination (EPD) . . . . . . 28 90 Appendix F. Design Considerations . . . . . . . . . . . . . . . 29 91 F.1. Vehicle ID . . . . . . . . . . . . . . . . . . . . . . . 29 92 F.2. Reliability Requirements . . . . . . . . . . . . . . . . 30 93 F.3. Multiple interfaces . . . . . . . . . . . . . . . . . . . 30 94 F.4. MAC Address Generation . . . . . . . . . . . . . . . . . 31 96 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode . . . . 31 97 Appendix H. Implementation Status . . . . . . . . . . . . . . . 32 98 H.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . 33 99 H.2. Capture in Normal Mode . . . . . . . . . . . . . . . . . 35 100 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 37 102 1. Introduction 104 This document describes the transmission of IPv6 packets on IEEE Std 105 802.11-OCB networks [IEEE-802.11-2016] (a.k.a "802.11p" see 106 Appendix B). This involves the layering of IPv6 networking on top of 107 the IEEE 802.11 MAC layer, with an LLC layer. Compared to running 108 IPv6 over the Ethernet MAC layer, there is no modification expected 109 to IEEE Std 802.11 MAC and Logical Link sublayers: IPv6 works fine 110 directly over 802.11-OCB too, with an LLC layer. 112 The IPv6 network layer operates on 802.11-OCB in the same manner as 113 operating on Ethernet, but there are two kinds of exceptions: 115 o Exceptions due to different operation of IPv6 network layer on 116 802.11 than on Ethernet. To satisfy these exceptions, this 117 document describes an Ethernet Adaptation Layer between Ethernet 118 headers and 802.11 headers. The Ethernet Adaptation Layer is 119 described Section 4.2.1. The operation of IP on Ethernet is 120 described in [RFC1042], [RFC2464] and 121 [I-D.hinden-6man-rfc2464bis]. 123 o Exceptions due to the OCB nature of 802.11-OCB compared to 802.11. 124 This has impacts on security, privacy, subnet structure and 125 handover behaviour. For security and privacy recommendations see 126 Section 5 and Section 4.5. The subnet structure is described in 127 Section 4.6. The handover behaviour on OCB links is not described 128 in this document. 130 In the published literature, many documents describe aspects and 131 problems related to running IPv6 over 802.11-OCB: 132 [I-D.ietf-ipwave-vehicular-networking-survey]. 134 2. Terminology 136 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 137 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 138 document are to be interpreted as described in RFC 2119 [RFC2119]. 140 WiFi: Wireless Fidelity. 142 IP-OBU (Internet Protocol On-Board Unit): an IP-OBU is a computer 143 situated in a vehicle such as an automobile, bicycle, or similar. It 144 has at least one IP interface that runs in mode OCB of 802.11, and 145 that has an "OBU" transceiver. 147 OBU (On-Board Unit): a term defined outside the IETF. An On-Board 148 Unit is a DSRC transceiver that is normally mounted in or on a 149 vehicle, or which in some instances may be a portable unit. An OBU 150 can be operational while a vehicle or person is either mobile or 151 stationary. The OBUs receive and contend for time to transmit on one 152 or more radio frequency (RF) channels. Except where specifically 153 excluded, OBU operation is permitted wherever vehicle operation or 154 human passage is permitted. The OBUs mounted in vehicles are 155 licensed by rule under part 95 of this chapter and communicate with 156 Roadside Units (RSUs) and other OBUs. Portable OBUs are also 157 licensed by rule under part 95 of this chapter. OBU operations in 158 the Unlicensed National Information Infrastructure (UNII) Bands 159 follow the rules in those bands. - [CFR 90.7 - Definitions]. The US 160 Federal Communications Commission (FCC) Dedicated Short Range 161 Communication (DSRC) is defined in the Code of Federal Regulations 162 (CFR) 47, Parts 90 and 95. At the time of the writing of this 163 Internet Draft, the last update of this document was dated October 164 1st, 2010. 166 IP-RSU (IP Road-Side Unit): an IP-RSU is situated along the road. An 167 IP-RSU has at least two distinct IP-enabled interfaces; at least one 168 interface is operated in mode OCB of IEEE 802.11 and is IP-enabled. 169 An IP-RSU is similar to a Wireless Termination Point (WTP), as 170 defined in [RFC5415], or an Access Point (AP), as defined in IEEE 171 documents, or an Access Network Router (ANR) defined in [RFC3753], 172 with one key particularity: the wireless PHY/MAC layer of at least 173 one of its IP-enabled interfaces is configured to operate in 174 802.11-OCB mode. The RSRU communicates with the IP-OBU in the 175 vehicle over 802.11 wireless link operating in OCB mode. 177 RSU (Road-Side Unit): a term defined outside of IETF. A Roadside 178 Unit is a DSRC transceiver that is mounted along a road or pedestrian 179 passageway. An RSU may also be mounted on a vehicle or is hand 180 carried, but it may only operate when the vehicle or hand- carried 181 unit is stationary. Furthermore, an RSU operating under this part is 182 restricted to the location where it is licensed to operate. However, 183 portable or hand-held RSUs are permitted to operate where they do not 184 interfere with a site-licensed operation. A RSU broadcasts data to 185 OBUs or exchanges data with OBUs in its communications zone. An RSU 186 also provides channel assignments and operating instructions to OBUs 187 in its communications zone, when required. - [CFR 90.7 - 188 Definitions]. At the time of the writing of this Internet Draft, the 189 last update of this document was dated October 1st, 2010. 191 OCB (outside the context of a basic service set - BSS): A mode of 192 operation in which a STA is not a member of a BSS and does not 193 utilize IEEE Std 802.11 authentication, association, or data 194 confidentiality. 196 802.11-OCB: mode specified in IEEE Std 802.11-2016 when the MIB 197 attribute dot11OCBActivited is true. The OCB mode requires 198 transmission of QoS data frames (IEEE Std 802.11e), half-clocked 199 operation (IEEE Std 802.11j), and use of 5.9 GHz frequency band. 200 Nota: any implementation should comply with standards and regulations 201 set in the different countries for using that frequency band. 203 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 205 The IEEE 802.11-OCB Networks are used for vehicular communications, 206 as 'Wireless Access in Vehicular Environments'. The IP communication 207 scenarios for these environments have been described in several 208 documents; in particular, we refer the reader to 209 [I-D.ietf-ipwave-vehicular-networking-survey], that lists some 210 scenarios and requirements for IP in Intelligent Transportation 211 Systems. 213 The link model is the following: STA --- 802.11-OCB --- STA. In 214 vehicular networks, STAs can be IP-RSUs and/or IP-OBUs. While 215 802.11-OCB is clearly specified, and the use of IPv6 over such link 216 is not radically new, the operating environment (vehicular networks) 217 brings in new perspectives. 219 The mechanisms for forming and terminating, discovering, peering and 220 mobility management for 802.11-OCB links are not described in this 221 document. 223 4. IPv6 over 802.11-OCB 225 4.1. Maximum Transmission Unit (MTU) 227 The default MTU for IP packets on 802.11-OCB MUST be 1500 octets. It 228 is the same value as IPv6 packets on Ethernet links, as specified in 229 [RFC2464]. This value of the MTU respects the recommendation that 230 every link on the Internet must have a minimum MTU of 1280 octets 231 (stated in [RFC8200], and the recommendations therein, especially 232 with respect to fragmentation). If IPv6 packets of size larger than 233 1500 bytes are sent on an 802.11-OCB interface card then the IP stack 234 will fragment. In case there are IP fragments, the field "Sequence 235 number" of the 802.11 Data header containing the IP fragment field is 236 increased. 238 Non-IP packets such as WAVE Short Message Protocol (WSMP) can be 239 delivered on 802.11-OCB links. Specifications of these packets are 240 out of scope of this document, and do not impose any limit on the MTU 241 size, allowing an arbitrary number of 'containers'. Non-IP packets 242 such as ETSI GeoNetworking packets have an MTU of 1492 bytes. The 243 operation of IPv6 over GeoNetworking is specified at 244 [ETSI-IPv6-GeoNetworking]. 246 4.2. Frame Format 248 IP packets are transmitted over 802.11-OCB as standard Ethernet 249 packets. As with all 802.11 frames, an Ethernet adaptation layer is 250 used with 802.11-OCB as well. This Ethernet Adaptation Layer 251 performing 802.11-to-Ethernet is described in Section 4.2.1. The 252 Ethernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal 86DD, 253 or otherwise #86DD). 255 The Frame format for transmitting IPv6 on 802.11-OCB networks is the 256 same as transmitting IPv6 on Ethernet networks, and is described in 257 section 3 of [RFC2464]. 259 1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1 260 is the binary representation of the EtherType value 0x86DD. 262 4.2.1. Ethernet Adaptation Layer 264 An 'adaptation' layer is inserted between a MAC layer and the 265 Networking layer. This is used to transform some parameters between 266 their form expected by the IP stack and the form provided by the MAC 267 layer. 269 An Ethernet Adaptation Layer makes an 802.11 MAC look to IP 270 Networking layer as a more traditional Ethernet layer. At reception, 271 this layer takes as input the IEEE 802.11 Data Header and the 272 Logical-Link Layer Control Header and produces an Ethernet II Header. 273 At sending, the reverse operation is performed. 275 The operation of the Ethernet Adaptation Layer is depicted by the 276 double arrow in Figure 1. 278 +--------------------+------------+-------------+---------+-----------+ 279 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer| 280 +--------------------+------------+-------------+---------+-----------+ 281 \ / \ / 282 ----------------------------- -------- 283 \---------------------------------------------/ 284 ^ 285 | 286 802.11-to-Ethernet Adaptation Layer 287 | 288 v 289 +---------------------+-------------+---------+ 290 | Ethernet II Header | IPv6 Header | Payload | 291 +---------------------+-------------+---------+ 293 Figure 1: Operation of the Ethernet Adaptation Layer 295 The Receiver and Transmitter Address fields in the 802.11 Data Header 296 contain the same values as the Destination and the Source Address 297 fields in the Ethernet II Header, respectively. The value of the 298 Type field in the LLC Header is the same as the value of the Type 299 field in the Ethernet II Header. 301 The ".11 Trailer" contains solely a 4-byte Frame Check Sequence. 303 Additionally, the Ethernet Adaptation Layer performs operations in 304 relation to IP fragmentation and MTU. One of these operations is 305 briefly described in Section 4.1. 307 In OCB mode, IPv6 packets MAY be transmitted either as "IEEE 802.11 308 Data" or alternatively as "IEEE 802.11 QoS Data", as illustrated in 309 Figure 2. 311 +--------------------+-------------+-------------+---------+-----------+ 312 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer| 313 +--------------------+-------------+-------------+---------+-----------+ 315 or 317 +--------------------+-------------+-------------+---------+-----------+ 318 | 802.11 QoS Data Hdr| LLC Header | IPv6 Header | Payload |.11 Trailer| 319 +--------------------+-------------+-------------+---------+-----------+ 321 Figure 2: 802.11 Data Header or 802.11 QoS Data Header 323 The distinction between the two formats is given by the value of the 324 field "Type/Subtype". The value of the field "Type/Subtype" in the 325 802.11 Data header is 0x0020. The value of the field "Type/Subtype" 326 in the 802.11 QoS header is 0x0028. 328 The mapping between qos-related fields in the IPv6 header (e.g. 329 "Traffic Class", "Flow label") and fields in the "802.11 QoS Data 330 Header" (e.g. "QoS Control") are not specified in this document. 331 Guidance for a potential mapping is provided in 332 [I-D.ietf-tsvwg-ieee-802-11], although it is not specific to OCB 333 mode. 335 The placement of IPv6 networking layer on Ethernet Adaptation Layer 336 is illustrated in Figure 3. 338 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 339 | IPv6 | 340 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 341 | Ethernet Adaptation Layer | 342 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 343 | 802.11 WiFi MAC | 344 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 345 | 802.11 WiFi PHY | 346 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 348 Figure 3: Ethernet Adaptation Layer stacked with other layers 350 (in the above figure, a WiFi profile is represented; this is used 351 also for OCB profile.) 353 Other alternative views of layering are EtherType Protocol 354 Discrimination (EPD), see Appendix E, and SNAP see [RFC1042]. 356 4.3. Link-Local Addresses 358 The link-local address of an 802.11-OCB interface is formed in the 359 same manner as on an Ethernet interface. This manner is described in 360 section 5 of [RFC2464]. Additionally, if stable identifiers are 361 needed, it is recommended to follow the Recommendation on Stable IPv6 362 Interface Identifiers [RFC8064]. Additionally, if semantically 363 opaque Interface Identifiers are needed, a potential method for 364 generating semantically opaque Interface Identifiers with IPv6 365 Stateless Address Autoconfiguration is given in [RFC7217]. 367 4.4. Address Mapping 369 For unicast as for multicast, there is no change from the unicast and 370 multicast address mapping format of Ethernet interfaces, as defined 371 by sections 6 and 7 of [RFC2464]. 373 4.4.1. Address Mapping -- Unicast 375 The procedure for mapping IPv6 unicast addresses into Ethernet link- 376 layer addresses is described in [RFC4861]. 378 4.4.2. Address Mapping -- Multicast 380 The multicast address mapping is performed according to the method 381 specified in section 7 of [RFC2464]. The meaning of the value "3333" 382 mentioned in that section 7 of [RFC2464] is defined in section 2.3.1 383 of [RFC7042]. 385 Transmitting IPv6 packets to multicast destinations over 802.11 links 386 proved to have some performance issues 387 [I-D.perkins-intarea-multicast-ieee802]. These issues may be 388 exacerbated in OCB mode. Solutions for these problems should 389 consider the OCB mode of operation. 391 4.5. Stateless Autoconfiguration 393 The Interface Identifier for an 802.11-OCB interface is formed using 394 the same rules as the Interface Identifier for an Ethernet interface; 395 this is described in section 4 of [RFC2464]. No changes are needed, 396 but some care must be taken when considering the use of the Stateless 397 Address Auto-Configuration procedure. 399 The bits in the interface identifier have no generic meaning and the 400 identifier should be treated as an opaque value. The bits 401 'Universal' and 'Group' in the identifier of an 802.11-OCB interface 402 are significant, as this is an IEEE link-layer address. The details 403 of this significance are described in [RFC7136]. 405 As with all Ethernet and 802.11 interface identifiers ([RFC7721]), 406 the identifier of an 802.11-OCB interface may involve privacy, MAC 407 address spoofing and IP address hijacking risks. A vehicle embarking 408 an OBU or an IP-OBU whose egress interface is 802.11-OCB may expose 409 itself to eavesdropping and subsequent correlation of data; this may 410 reveal data considered private by the vehicle owner; there is a risk 411 of being tracked; see the privacy considerations described in 412 Appendix F. 414 If stable Interface Identifiers are needed in order to form IPv6 415 addresses on 802.11-OCB links, it is recommended to follow the 416 recommendation in [RFC8064]. Additionally, if semantically opaque 417 Interface Identifiers are needed, a potential method for generating 418 semantically opaque Interface Identifiers with IPv6 Stateless Address 419 Autoconfiguration is given in [RFC7217]. 421 4.6. Subnet Structure 423 A subnet is formed by the external 802.11-OCB interfaces of vehicles 424 that are in close range (not their on-board interfaces). This 425 ephemeral subnet structure is strongly influenced by the mobility of 426 vehicles: the 802.11 hidden node effects appear. On another hand, 427 the structure of the internal subnets in each car is relatively 428 stable. 430 The 802.11 networks in OCB mode may be considered as 'ad-hoc' 431 networks. The addressing model for such networks is described in 432 [RFC5889]. 434 An addressing model involves several types of addresses, like 435 Globally-unique Addresses (GUA), Link-Local Addresses (LL) and Unique 436 Local Addresses (ULA). The subnet structure in 'ad-hoc' networks may 437 have characteristics that lead to difficulty of using GUAs derived 438 from a received prefix, but the LL addresses may be easier to use 439 since the prefix is constant. 441 5. Security Considerations 443 Any security mechanism at the IP layer or above that may be carried 444 out for the general case of IPv6 may also be carried out for IPv6 445 operating over 802.11-OCB. 447 The OCB operation is stripped off of all existing 802.11 link-layer 448 security mechanisms. There is no encryption applied below the 449 network layer running on 802.11-OCB. At application layer, the IEEE 450 1609.2 document [IEEE-1609.2] does provide security services for 451 certain applications to use; application-layer mechanisms are out-of- 452 scope of this document. On another hand, a security mechanism 453 provided at networking layer, such as IPsec [RFC4301], may provide 454 data security protection to a wider range of applications. 456 802.11-OCB does not provide any cryptographic protection, because it 457 operates outside the context of a BSS (no Association Request/ 458 Response, no Challenge messages). Any attacker can therefore just 459 sit in the near range of vehicles, sniff the network (just set the 460 interface card's frequency to the proper range) and perform attacks 461 without needing to physically break any wall. Such a link is less 462 protected than commonly used links (wired link or protected 802.11). 464 The potential attack vectors are: MAC address spoofing, IP address 465 and session hijacking and privacy violation. 467 Within the IPsec Security Architecture [RFC4301], the IPsec AH and 468 ESP headers [RFC4302] and [RFC4303] respectively, its multicast 469 extensions [RFC5374], HTTPS [RFC2818] and SeND [RFC3971] protocols 470 can be used to protect communications. Further, the assistance of 471 proper Public Key Infrastructure (PKI) protocols [RFC4210] is 472 necessary to establish credentials. More IETF protocols are 473 available in the toolbox of the IP security protocol designer. 474 Certain ETSI protocols related to security protocols in Intelligent 475 Transportation Systems are described in [ETSI-sec-archi]. 477 As with all Ethernet and 802.11 interface identifiers, there may 478 exist privacy risks in the use of 802.11-OCB interface identifiers. 479 Moreover, in outdoors vehicular settings, the privacy risks are more 480 important than in indoors settings. New risks are induced by the 481 possibility of attacker sniffers deployed along routes which listen 482 for IP packets of vehicles passing by. For this reason, in the 483 802.11-OCB deployments, there is a strong necessity to use protection 484 tools such as dynamically changing MAC addresses. This may help 485 mitigate privacy risks to a certain level. On another hand, it may 486 have an impact in the way typical IPv6 address auto-configuration is 487 performed for vehicles (SLAAC would rely on MAC addresses and would 488 hence dynamically change the affected IP address), in the way the 489 IPv6 Privacy addresses were used, and other effects. 491 6. IANA Considerations 493 No request to IANA. 495 7. Contributors 497 Christian Huitema, Tony Li. 499 Romain Kuntz contributed extensively about IPv6 handovers between 500 links running outside the context of a BSS (802.11-OCB links). 502 Tim Leinmueller contributed the idea of the use of IPv6 over 503 802.11-OCB for distribution of certificates. 505 Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey 506 Voronov provided significant feedback on the experience of using IP 507 messages over 802.11-OCB in initial trials. 509 Michelle Wetterwald contributed extensively the MTU discussion, 510 offered the ETSI ITS perspective, and reviewed other parts of the 511 document. 513 8. Acknowledgements 515 The authors would like to thank Witold Klaudel, Ryuji Wakikawa, 516 Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan 517 Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray 518 Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, 519 Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne, 520 Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark, 521 Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley, Sandra 522 Cespedes, Mariano Falcitelli, Sri Gundavelli, Abdussalam Baryun, 523 Margaret Cullen, Erik Kline and William Whyte. Their valuable 524 comments clarified particular issues and generally helped to improve 525 the document. 527 Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB 528 drivers for linux and described how. 530 For the multicast discussion, the authors would like to thank Owen 531 DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and 532 participants to discussions in network working groups. 534 The authors would like to thank participants to the Birds-of- 535 a-Feather "Intelligent Transportation Systems" meetings held at IETF 536 in 2016. 538 9. References 540 9.1. Normative References 542 [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission 543 of IP datagrams over IEEE 802 networks", STD 43, RFC 1042, 544 DOI 10.17487/RFC1042, February 1988, 545 . 547 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 548 Requirement Levels", BCP 14, RFC 2119, 549 DOI 10.17487/RFC2119, March 1997, 550 . 552 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 553 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 554 . 556 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 557 DOI 10.17487/RFC2818, May 2000, 558 . 560 [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related 561 Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, 562 . 564 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 565 "SEcure Neighbor Discovery (SEND)", RFC 3971, 566 DOI 10.17487/RFC3971, March 2005, 567 . 569 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 570 "Randomness Requirements for Security", BCP 106, RFC 4086, 571 DOI 10.17487/RFC4086, June 2005, 572 . 574 [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, 575 "Internet X.509 Public Key Infrastructure Certificate 576 Management Protocol (CMP)", RFC 4210, 577 DOI 10.17487/RFC4210, September 2005, 578 . 580 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 581 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 582 December 2005, . 584 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 585 DOI 10.17487/RFC4302, December 2005, 586 . 588 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 589 RFC 4303, DOI 10.17487/RFC4303, December 2005, 590 . 592 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 593 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 594 DOI 10.17487/RFC4861, September 2007, 595 . 597 [RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast 598 Extensions to the Security Architecture for the Internet 599 Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008, 600 . 602 [RFC5415] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, 603 Ed., "Control And Provisioning of Wireless Access Points 604 (CAPWAP) Protocol Specification", RFC 5415, 605 DOI 10.17487/RFC5415, March 2009, 606 . 608 [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing 609 Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889, 610 September 2010, . 612 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 613 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 614 2011, . 616 [RFC7042] Eastlake 3rd, D. and J. Abley, "IANA Considerations and 617 IETF Protocol and Documentation Usage for IEEE 802 618 Parameters", BCP 141, RFC 7042, DOI 10.17487/RFC7042, 619 October 2013, . 621 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 622 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 623 February 2014, . 625 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 626 Interface Identifiers with IPv6 Stateless Address 627 Autoconfiguration (SLAAC)", RFC 7217, 628 DOI 10.17487/RFC7217, April 2014, 629 . 631 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 632 Considerations for IPv6 Address Generation Mechanisms", 633 RFC 7721, DOI 10.17487/RFC7721, March 2016, 634 . 636 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 637 "Recommendation on Stable IPv6 Interface Identifiers", 638 RFC 8064, DOI 10.17487/RFC8064, February 2017, 639 . 641 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 642 (IPv6) Specification", STD 86, RFC 8200, 643 DOI 10.17487/RFC8200, July 2017, 644 . 646 9.2. Informative References 648 [ETSI-IPv6-GeoNetworking] 649 "ETSI EN 302 636-6-1 v1.2.1 (2014-05), ETSI, European 650 Standard, Intelligent Transportation Systems (ITS); 651 Vehicular Communications; Geonetworking; Part 6: Internet 652 Integration; Sub-part 1: Transmission of IPv6 Packets over 653 Geonetworking Protocols. Downloaded on September 9th, 654 2017, freely available from ETSI website at URL 655 http://www.etsi.org/deliver/ 656 etsi_en/302600_302699/30263601/01.02.01_60/ 657 en_30263601v010201p.pdf". 659 [ETSI-sec-archi] 660 "ETSI TS 102 940 V1.2.1 (2016-11), ETSI Technical 661 Specification, Intelligent Transport Systems (ITS); 662 Security; ITS communications security architecture and 663 security management, November 2016. Downloaded on 664 September 9th, 2017, freely available from ETSI website at 665 URL http://www.etsi.org/deliver/ 666 etsi_ts/102900_102999/102940/01.02.01_60/ 667 ts_102940v010201p.pdf". 669 [I-D.hinden-6man-rfc2464bis] 670 Crawford, M. and R. Hinden, "Transmission of IPv6 Packets 671 over Ethernet Networks", draft-hinden-6man-rfc2464bis-02 672 (work in progress), March 2017. 674 [I-D.ietf-ipwave-vehicular-networking-survey] 675 Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M. 676 Wetterwald, "Survey on IP-based Vehicular Networking for 677 Intelligent Transportation Systems", draft-ietf-ipwave- 678 vehicular-networking-survey-00 (work in progress), July 679 2017. 681 [I-D.ietf-tsvwg-ieee-802-11] 682 Szigeti, T., Henry, J., and F. Baker, "Diffserv to IEEE 683 802.11 Mapping", draft-ietf-tsvwg-ieee-802-11-11 (work in 684 progress), December 2017. 686 [I-D.perkins-intarea-multicast-ieee802] 687 Perkins, C., Stanley, D., Kumari, W., and J. Zuniga, 688 "Multicast Considerations over IEEE 802 Wireless Media", 689 draft-perkins-intarea-multicast-ieee802-03 (work in 690 progress), July 2017. 692 [IEEE-1609.2] 693 "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access 694 in Vehicular Environments (WAVE) -- Security Services for 695 Applications and Management Messages. Example URL 696 http://ieeexplore.ieee.org/document/7426684/ accessed on 697 August 17th, 2017.". 699 [IEEE-1609.3] 700 "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access 701 in Vehicular Environments (WAVE) -- Networking Services. 702 Example URL http://ieeexplore.ieee.org/document/7458115/ 703 accessed on August 17th, 2017.". 705 [IEEE-1609.4] 706 "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access 707 in Vehicular Environments (WAVE) -- Multi-Channel 708 Operation. Example URL 709 http://ieeexplore.ieee.org/document/7435228/ accessed on 710 August 17th, 2017.". 712 [IEEE-802.11-2016] 713 "IEEE Standard 802.11-2016 - IEEE Standard for Information 714 Technology - Telecommunications and information exchange 715 between systems Local and metropolitan area networks - 716 Specific requirements - Part 11: Wireless LAN Medium 717 Access Control (MAC) and Physical Layer (PHY) 718 Specifications. Status - Active Standard. Description 719 retrieved freely on September 12th, 2017, at URL 720 https://standards.ieee.org/findstds/ 721 standard/802.11-2016.html". 723 [IEEE-802.11p-2010] 724 "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information 725 Technology - Telecommunications and information exchange 726 between systems - Local and metropolitan area networks - 727 Specific requirements, Part 11: Wireless LAN Medium Access 728 Control (MAC) and Physical Layer (PHY) Specifications, 729 Amendment 6: Wireless Access in Vehicular Environments; 730 document freely available at URL 731 http://standards.ieee.org/getieee802/ 732 download/802.11p-2010.pdf retrieved on September 20th, 733 2013.". 735 Appendix A. ChangeLog 737 The changes are listed in reverse chronological order, most recent 738 changes appearing at the top of the list. 740 From draft-ietf-ipwave-ipv6-over-80211ocb-12 to draft-ietf-ipwave- 741 ipv6-over-80211ocb-13 743 o Substituted "IP-OBU" for "OBRU", and "IP-RSU" for "RSRU" 744 throughout and improved OBU-related definitions in the Terminology 745 section. 747 From draft-ietf-ipwave-ipv6-over-80211ocb-11 to draft-ietf-ipwave- 748 ipv6-over-80211ocb-12 750 o Improved the appendix about "MAC Address Generation" by expressing 751 the technique to be an optional suggestion, not a mandatory 752 mechanism. 754 From draft-ietf-ipwave-ipv6-over-80211ocb-10 to draft-ietf-ipwave- 755 ipv6-over-80211ocb-11 757 o Shortened the paragraph on forming/terminating 802.11-OCB links. 759 o Moved the draft tsvwg-ieee-802-11 to Informative References. 761 From draft-ietf-ipwave-ipv6-over-80211ocb-09 to draft-ietf-ipwave- 762 ipv6-over-80211ocb-10 764 o Removed text requesting a new Group ID for multicast for OCB. 766 o Added a clarification of the meaning of value "3333" in the 767 section Address Mapping -- Multicast. 769 o Added note clarifying that in Europe the regional authority is not 770 ETSI, but "ECC/CEPT based on ENs from ETSI". 772 o Added note stating that the manner in which two STAtions set their 773 communication channel is not described in this document. 775 o Added a time qualifier to state that the "each node is represented 776 uniquely at a certain point in time." 778 o Removed text "This section may need to be moved" (the "Reliability 779 Requirements" section). This section stays there at this time. 781 o In the term definition "802.11-OCB" added a note stating that "any 782 implementation should comply with standards and regulations set in 783 the different countries for using that frequency band." 785 o In the RSU term definition, added a sentence explaining the 786 difference between RSU and RSRU: in terms of number of interfaces 787 and IP forwarding. 789 o Replaced "with at least two IP interfaces" with "with at least two 790 real or virtual IP interfaces". 792 o Added a term in the Terminology for "OBU". However the definition 793 is left empty, as this term is defined outside IETF. 795 o Added a clarification that it is an OBU or an OBRU in this phrase 796 "A vehicle embarking an OBU or an OBRU". 798 o Checked the entire document for a consistent use of terms OBU and 799 OBRU. 801 o Added note saying that "'p' is a letter identifying the 802 Ammendment". 804 o Substituted lower case for capitals SHALL or MUST in the 805 Appendices. 807 o Added reference to RFC7042, helpful in the 3333 explanation. 808 Removed reference to individual submission draft-petrescu-its- 809 scenario-reqs and added reference to draft-ietf-ipwave-vehicular- 810 networking-survey. 812 o Added figure captions, figure numbers, and references to figure 813 numbers instead of 'below'. Replaced "section Section" with 814 "section" throughout. 816 o Minor typographical errors. 818 From draft-ietf-ipwave-ipv6-over-80211ocb-08 to draft-ietf-ipwave- 819 ipv6-over-80211ocb-09 821 o Significantly shortened the Address Mapping sections, by text 822 copied from RFC2464, and rather referring to it. 824 o Moved the EPD description to an Appendix on its own. 826 o Shortened the Introduction and the Abstract. 828 o Moved the tutorial section of OCB mode introduced to .11, into an 829 appendix. 831 o Removed the statement that suggests that for routing purposes a 832 prefix exchange mechanism could be needed. 834 o Removed refs to RFC3963, RFC4429 and RFC6775; these are about ND, 835 MIP/NEMO and oDAD; they were referred in the handover discussion 836 section, which is out. 838 o Updated a reference from individual submission to now a WG item in 839 IPWAVE: the survey document. 841 o Added term definition for WiFi. 843 o Updated the authorship and expanded the Contributors section. 845 o Corrected typographical errors. 847 From draft-ietf-ipwave-ipv6-over-80211ocb-07 to draft-ietf-ipwave- 848 ipv6-over-80211ocb-08 850 o Removed the per-channel IPv6 prohibition text. 852 o Corrected typographical errors. 854 From draft-ietf-ipwave-ipv6-over-80211ocb-06 to draft-ietf-ipwave- 855 ipv6-over-80211ocb-07 857 o Added new terms: OBRU and RSRU ('R' for Router). Refined the 858 existing terms RSU and OBU, which are no longer used throughout 859 the document. 861 o Improved definition of term "802.11-OCB". 863 o Clarified that OCB does not "strip" security, but that the 864 operation in OCB mode is "stripped off of all .11 security". 866 o Clarified that theoretical OCB bandwidth speed is 54mbits, but 867 that a commonly observed bandwidth in IP-over-OCB is 12mbit/s. 869 o Corrected typographical errors, and improved some phrasing. 871 From draft-ietf-ipwave-ipv6-over-80211ocb-05 to draft-ietf-ipwave- 872 ipv6-over-80211ocb-06 874 o Updated references of 802.11-OCB document from -2012 to the IEEE 875 802.11-2016. 877 o In the LL address section, and in SLAAC section, added references 878 to 7217 opaque IIDs and 8064 stable IIDs. 880 From draft-ietf-ipwave-ipv6-over-80211ocb-04 to draft-ietf-ipwave- 881 ipv6-over-80211ocb-05 883 o Lengthened the title and cleanded the abstract. 885 o Added text suggesting LLs may be easy to use on OCB, rather than 886 GUAs based on received prefix. 888 o Added the risks of spoofing and hijacking. 890 o Removed the text speculation on adoption of the TSA message. 892 o Clarified that the ND protocol is used. 894 o Clarified what it means "No association needed". 896 o Added some text about how two STAs discover each other. 898 o Added mention of external (OCB) and internal network (stable), in 899 the subnet structure section. 901 o Added phrase explaining that both .11 Data and .11 QoS Data 902 headers are currently being used, and may be used in the future. 904 o Moved the packet capture example into an Appendix Implementation 905 Status. 907 o Suggested moving the reliability requirements appendix out into 908 another document. 910 o Added a IANA Consiserations section, with content, requesting for 911 a new multicast group "all OCB interfaces". 913 o Added new OBU term, improved the RSU term definition, removed the 914 ETTC term, replaced more occurences of 802.11p, 802.11 OCB with 915 802.11-OCB. 917 o References: 919 * Added an informational reference to ETSI's IPv6-over- 920 GeoNetworking. 922 * Added more references to IETF and ETSI security protocols. 924 * Updated some references from I-D to RFC, and from old RFC to 925 new RFC numbers. 927 * Added reference to multicast extensions to IPsec architecture 928 RFC. 930 * Added a reference to 2464-bis. 932 * Removed FCC informative references, because not used. 934 o Updated the affiliation of one author. 936 o Reformulation of some phrases for better readability, and 937 correction of typographical errors. 939 From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave- 940 ipv6-over-80211ocb-04 942 o Removed a few informative references pointing to Dx draft IEEE 943 1609 documents. 945 o Removed outdated informative references to ETSI documents. 947 o Added citations to IEEE 1609.2, .3 and .4-2016. 949 o Minor textual issues. 951 From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave- 952 ipv6-over-80211ocb-03 954 o Keep the previous text on multiple addresses, so remove talk about 955 MIP6, NEMOv6 and MCoA. 957 o Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon. 959 o Clarified the figure showing Infrastructure mode and OCB mode side 960 by side. 962 o Added a reference to the IP Security Architecture RFC. 964 o Detailed the IPv6-per-channel prohibition paragraph which reflects 965 the discussion at the last IETF IPWAVE WG meeting. 967 o Added section "Address Mapping -- Unicast". 969 o Added the ".11 Trailer" to pictures of 802.11 frames. 971 o Added text about SNAP carrying the Ethertype. 973 o New RSU definition allowing for it be both a Router and not 974 necessarily a Router some times. 976 o Minor textual issues. 978 From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave- 979 ipv6-over-80211ocb-02 980 o Replaced almost all occurences of 802.11p with 802.11-OCB, leaving 981 only when explanation of evolution was necessary. 983 o Shortened by removing parameter details from a paragraph in the 984 Introduction. 986 o Moved a reference from Normative to Informative. 988 o Added text in intro clarifying there is no handover spec at IEEE, 989 and that 1609.2 does provide security services. 991 o Named the contents the fields of the EthernetII header (including 992 the Ethertype bitstring). 994 o Improved relationship between two paragraphs describing the 995 increase of the Sequence Number in 802.11 header upon IP 996 fragmentation. 998 o Added brief clarification of "tracking". 1000 From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave- 1001 ipv6-over-80211ocb-01 1003 o Introduced message exchange diagram illustrating differences 1004 between 802.11 and 802.11 in OCB mode. 1006 o Introduced an appendix listing for information the set of 802.11 1007 messages that may be transmitted in OCB mode. 1009 o Removed appendix sections "Privacy Requirements", "Authentication 1010 Requirements" and "Security Certificate Generation". 1012 o Removed appendix section "Non IP Communications". 1014 o Introductory phrase in the Security Considerations section. 1016 o Improved the definition of "OCB". 1018 o Introduced theoretical stacked layers about IPv6 and IEEE layers 1019 including EPD. 1021 o Removed the appendix describing the details of prohibiting IPv6 on 1022 certain channels relevant to 802.11-OCB. 1024 o Added a brief reference in the privacy text about a precise clause 1025 in IEEE 1609.3 and .4. 1027 o Clarified the definition of a Road Side Unit. 1029 o Removed the discussion about security of WSA (because is non-IP). 1031 o Removed mentioning of the GeoNetworking discussion. 1033 o Moved references to scientific articles to a separate 'overview' 1034 draft, and referred to it. 1036 Appendix B. 802.11p 1038 The term "802.11p" is an earlier definition. The behaviour of 1039 "802.11p" networks is rolled in the document IEEE Std 802.11-2016. 1040 In that document the term 802.11p disappears. Instead, each 802.11p 1041 feature is conditioned by the Management Information Base (MIB) 1042 attribute "OCBActivated". Whenever OCBActivated is set to true the 1043 IEEE Std 802.11 OCB state is activated. For example, an 802.11 1044 STAtion operating outside the context of a basic service set has the 1045 OCBActivated flag set. Such a station, when it has the flag set, 1046 uses a BSS identifier equal to ff:ff:ff:ff:ff:ff. 1048 Appendix C. Aspects introduced by the OCB mode to 802.11 1050 In the IEEE 802.11-OCB mode, all nodes in the wireless range can 1051 directly communicate with each other without involving authentication 1052 or association procedures. At link layer, it is necessary to set the 1053 same channel number (or frequency) on two stations that need to 1054 communicate with each other. The manner in which stations set their 1055 channel number is not specified in this document. Stations STA1 and 1056 STA2 can exchange IP packets if they are set on the same channel. At 1057 IP layer, they then discover each other by using the IPv6 Neighbor 1058 Discovery protocol. 1060 Briefly, the IEEE 802.11-OCB mode has the following properties: 1062 o The use by each node of a 'wildcard' BSSID (i.e., each bit of the 1063 BSSID is set to 1) 1065 o No IEEE 802.11 Beacon frames are transmitted 1067 o No authentication is required in order to be able to communicate 1069 o No association is needed in order to be able to communicate 1071 o No encryption is provided in order to be able to communicate 1073 o Flag dot11OCBActivated is set to true 1075 All the nodes in the radio communication range (IP-OBU and IP-RSU) 1076 receive all the messages transmitted (IP-OBU and IP-RSU) within the 1077 radio communications range. The eventual conflict(s) are resolved by 1078 the MAC CDMA function. 1080 The message exchange diagram in Figure 4 illustrates a comparison 1081 between traditional 802.11 and 802.11 in OCB mode. The 'Data' 1082 messages can be IP packets such as HTTP or others. Other 802.11 1083 management and control frames (non IP) may be transmitted, as 1084 specified in the 802.11 standard. For information, the names of 1085 these messages as currently specified by the 802.11 standard are 1086 listed in Appendix G. 1088 STA AP STA1 STA2 1089 | | | | 1090 |<------ Beacon -------| |<------ Data -------->| 1091 | | | | 1092 |---- Probe Req. ----->| |<------ Data -------->| 1093 |<--- Probe Res. ------| | | 1094 | | |<------ Data -------->| 1095 |---- Auth Req. ------>| | | 1096 |<--- Auth Res. -------| |<------ Data -------->| 1097 | | | | 1098 |---- Asso Req. ------>| |<------ Data -------->| 1099 |<--- Asso Res. -------| | | 1100 | | |<------ Data -------->| 1101 |<------ Data -------->| | | 1102 |<------ Data -------->| |<------ Data -------->| 1104 (i) 802.11 Infrastructure mode (ii) 802.11-OCB mode 1106 Figure 4: Difference between messages exchanged on 802.11 (left) and 1107 802.11-OCB (right) 1109 The interface 802.11-OCB was specified in IEEE Std 802.11p (TM) -2010 1110 [IEEE-802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, 1111 titled "Amendment 6: Wireless Access in Vehicular Environments". 1112 Since then, this amendment has been integrated in IEEE 802.11(TM) 1113 -2012 and -2016 [IEEE-802.11-2016]. 1115 In document 802.11-2016, anything qualified specifically as 1116 "OCBActivated", or "outside the context of a basic service" set to be 1117 true, then it is actually referring to OCB aspects introduced to 1118 802.11. 1120 In order to delineate the aspects introduced by 802.11-OCB to 802.11, 1121 we refer to the earlier [IEEE-802.11p-2010]. The amendment is 1122 concerned with vehicular communications, where the wireless link is 1123 similar to that of Wireless LAN (using a PHY layer specified by 1124 802.11a/b/g/n), but which needs to cope with the high mobility factor 1125 inherent in scenarios of communications between moving vehicles, and 1126 between vehicles and fixed infrastructure deployed along roads. 1127 While 'p' is a letter identifying the Ammendment, just like 'a, b, g' 1128 and 'n' are, 'p' is concerned more with MAC modifications, and a 1129 little with PHY modifications; the others are mainly about PHY 1130 modifications. It is possible in practice to combine a 'p' MAC with 1131 an 'a' PHY by operating outside the context of a BSS with OFDM at 1132 5.4GHz and 5.9GHz. 1134 The 802.11-OCB links are specified to be compatible as much as 1135 possible with the behaviour of 802.11a/b/g/n and future generation 1136 IEEE WLAN links. From the IP perspective, an 802.11-OCB MAC layer 1137 offers practically the same interface to IP as the WiFi and Ethernet 1138 layers do (802.11a/b/g/n and 802.3). A packet sent by an IP-OBU may 1139 be received by one or multiple IP-RSUs. The link-layer resolution is 1140 performed by using the IPv6 Neighbor Discovery protocol. 1142 To support this similarity statement (IPv6 is layered on top of LLC 1143 on top of 802.11-OCB, in the same way that IPv6 is layered on top of 1144 LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on 1145 top of 802.3 (for Ethernet)) it is useful to analyze the differences 1146 between 802.11-OCB and 802.11 specifications. During this analysis, 1147 we note that whereas 802.11-OCB lists relatively complex and numerous 1148 changes to the MAC layer (and very little to the PHY layer), there 1149 are only a few characteristics which may be important for an 1150 implementation transmitting IPv6 packets on 802.11-OCB links. 1152 The most important 802.11-OCB point which influences the IPv6 1153 functioning is the OCB characteristic; an additional, less direct 1154 influence, is the maximum bandwidth afforded by the PHY modulation/ 1155 demodulation methods and channel access specified by 802.11-OCB. The 1156 maximum bandwidth theoretically possible in 802.11-OCB is 54 Mbit/s 1157 (when using, for example, the following parameters: 20 MHz channel; 1158 modulation 64-QAM; coding rate R is 3/4); in practice of IP-over- 1159 802.11-OCB a commonly observed figure is 12Mbit/s; this bandwidth 1160 allows the operation of a wide range of protocols relying on IPv6. 1162 o Operation Outside the Context of a BSS (OCB): the (earlier 1163 802.11p) 802.11-OCB links are operated without a Basic Service Set 1164 (BSS). This means that the frames IEEE 802.11 Beacon, Association 1165 Request/Response, Authentication Request/Response, and similar, 1166 are not used. The used identifier of BSS (BSSID) has a 1167 hexadecimal value always 0xffffffffffff (48 '1' bits, represented 1168 as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' 1169 BSSID), as opposed to an arbitrary BSSID value set by 1170 administrator (e.g. 'My-Home-AccessPoint'). The OCB operation - 1171 namely the lack of beacon-based scanning and lack of 1172 authentication - should be taken into account when the Mobile IPv6 1173 protocol [RFC6275] and the protocols for IP layer security 1174 [RFC4301] are used. The way these protocols adapt to OCB is not 1175 described in this document. 1177 o Timing Advertisement: is a new message defined in 802.11-OCB, 1178 which does not exist in 802.11a/b/g/n. This message is used by 1179 stations to inform other stations about the value of time. It is 1180 similar to the time as delivered by a GNSS system (Galileo, GPS, 1181 ...) or by a cellular system. This message is optional for 1182 implementation. 1184 o Frequency range: this is a characteristic of the PHY layer, with 1185 almost no impact on the interface between MAC and IP. However, it 1186 is worth considering that the frequency range is regulated by a 1187 regional authority (ARCEP, ECC/CEPT based on ENs from ETSI, FCC, 1188 etc.); as part of the regulation process, specific applications 1189 are associated with specific frequency ranges. In the case of 1190 802.11-OCB, the regulator associates a set of frequency ranges, or 1191 slots within a band, to the use of applications of vehicular 1192 communications, in a band known as "5.9GHz". The 5.9GHz band is 1193 different from the 2.4GHz and 5GHz bands used by Wireless LAN. 1194 However, as with Wireless LAN, the operation of 802.11-OCB in 1195 "5.9GHz" bands is exempt from owning a license in EU (in US the 1196 5.9GHz is a licensed band of spectrum; for the fixed 1197 infrastructure an explicit FCC authorization is required; for an 1198 on-board device a 'licensed-by-rule' concept applies: rule 1199 certification conformity is required.) Technical conditions are 1200 different than those of the bands "2.4GHz" or "5GHz". The allowed 1201 power levels, and implicitly the maximum allowed distance between 1202 vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20 1203 dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum 1204 distance of approximately 1km, compared to approximately 50m. 1205 Additionally, specific conditions related to congestion avoidance, 1206 jamming avoidance, and radar detection are imposed on the use of 1207 DSRC (in US) and on the use of frequencies for Intelligent 1208 Transportation Systems (in EU), compared to Wireless LAN 1209 (802.11a/b/g/n). 1211 o 'Half-rate' encoding: as the frequency range, this parameter is 1212 related to PHY, and thus has not much impact on the interface 1213 between the IP layer and the MAC layer. 1215 o In vehicular communications using 802.11-OCB links, there are 1216 strong privacy requirements with respect to addressing. While the 1217 802.11-OCB standard does not specify anything in particular with 1218 respect to MAC addresses, in these settings there exists a strong 1219 need for dynamic change of these addresses (as opposed to the non- 1220 vehicular settings - real wall protection - where fixed MAC 1221 addresses do not currently pose some privacy risks). This is 1222 further described in Section 5. A relevant function is described 1223 in IEEE 1609.3-2016 [IEEE-1609.3], clause 5.5.1 and IEEE 1224 1609.4-2016 [IEEE-1609.4], clause 6.7. 1226 Other aspects particular to 802.11-OCB, which are also particular to 1227 802.11 (e.g. the 'hidden node' operation), may have an influence on 1228 the use of transmission of IPv6 packets on 802.11-OCB networks. The 1229 OCB subnet structure is described in Section 4.6. 1231 Appendix D. Changes Needed on a software driver 802.11a to become a 1232 802.11-OCB driver 1234 The 802.11p amendment modifies both the 802.11 stack's physical and 1235 MAC layers but all the induced modifications can be quite easily 1236 obtained by modifying an existing 802.11a ad-hoc stack. 1238 Conditions for a 802.11a hardware to be 802.11-OCB compliant: 1240 o The PHY entity shall be an orthogonal frequency division 1241 multiplexing (OFDM) system. It must support the frequency bands 1242 on which the regulator recommends the use of ITS communications, 1243 for example using IEEE 802.11-OCB layer, in France: 5875MHz to 1244 5925MHz. 1246 o The OFDM system must provide a "half-clocked" operation using 10 1247 MHz channel spacings. 1249 o The chip transmit spectrum mask must be compliant to the "Transmit 1250 spectrum mask" from the IEEE 802.11p amendment (but experimental 1251 environments tolerate otherwise). 1253 o The chip should be able to transmit up to 44.8 dBm when used by 1254 the US government in the United States, and up to 33 dBm in 1255 Europe; other regional conditions apply. 1257 Changes needed on the network stack in OCB mode: 1259 o Physical layer: 1261 * The chip must use the Orthogonal Frequency Multiple Access 1262 (OFDM) encoding mode. 1264 * The chip must be set in half-mode rate mode (the internal clock 1265 frequency is divided by two). 1267 * The chip must use dedicated channels and should allow the use 1268 of higher emission powers. This may require modifications to 1269 the local computer file that describes regulatory domains 1270 rules, if used by the kernel to enforce local specific 1271 restrictions. Such modifications to the local computer file 1272 must respect the location-specific regulatory rules. 1274 MAC layer: 1276 * All management frames (beacons, join, leave, and others) 1277 emission and reception must be disabled except for frames of 1278 subtype Action and Timing Advertisement (defined below). 1280 * No encryption key or method must be used. 1282 * Packet emission and reception must be performed as in ad-hoc 1283 mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff). 1285 * The functions related to joining a BSS (Association Request/ 1286 Response) and for authentication (Authentication Request/Reply, 1287 Challenge) are not called. 1289 * The beacon interval is always set to 0 (zero). 1291 * Timing Advertisement frames, defined in the amendment, should 1292 be supported. The upper layer should be able to trigger such 1293 frames emission and to retrieve information contained in 1294 received Timing Advertisements. 1296 Appendix E. EtherType Protocol Discrimination (EPD) 1298 A more theoretical and detailed view of layer stacking, and 1299 interfaces between the IP layer and 802.11-OCB layers, is illustrated 1300 in Figure 5. The IP layer operates on top of the EtherType Protocol 1301 Discrimination (EPD); this Discrimination layer is described in IEEE 1302 Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP 1303 (Link Layer Control Service Access Point). 1305 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1306 | IPv6 | 1307 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ 1308 { LLC_SAP } 802.11-OCB 1309 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary 1310 | EPD | | | 1311 | | MLME | | 1312 +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | 1313 | MAC Sublayer | | | 802.11-OCB 1314 | and ch. coord. | | SME | Services 1315 +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | 1316 | | PLME | | 1317 | PHY Layer | PLME_SAP | 1318 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1320 Figure 5: EtherType Protocol Discrimination 1322 Appendix F. Design Considerations 1324 The networks defined by 802.11-OCB are in many ways similar to other 1325 networks of the 802.11 family. In theory, the encapsulation of IPv6 1326 over 802.11-OCB could be very similar to the operation of IPv6 over 1327 other networks of the 802.11 family. However, the high mobility, 1328 strong link asymmetry and very short connection makes the 802.11-OCB 1329 link significantly different from other 802.11 networks. Also, the 1330 automotive applications have specific requirements for reliability, 1331 security and privacy, which further add to the particularity of the 1332 802.11-OCB link. 1334 F.1. Vehicle ID 1336 In automotive networks it is required that each node is represented 1337 uniquely at a certain point in time. Accordingly, a vehicle must be 1338 identified by at least one unique identifier. The current 1339 specification at ETSI and at IEEE 1609 identifies a vehicle by its 1340 MAC address, which is obtained from the 802.11-OCB Network Interface 1341 Card (NIC). 1343 In case multiple 802.11-OCB NICs are present in one car, implicitely 1344 multiple vehicle IDs will be generated. Additionally, some software 1345 generates a random MAC address each time the computer boots; this 1346 constitutes an additional difficulty. 1348 A mechanim to uniquely identify a vehicle irrespectively to the 1349 multiplicity of NICs, or frequent MAC address generation, is 1350 necessary. 1352 F.2. Reliability Requirements 1354 The dynamically changing topology, short connectivity, mobile 1355 transmitter and receivers, different antenna heights, and many-to- 1356 many communication types, make IEEE 802.11-OCB links significantly 1357 different from other IEEE 802.11 links. Any IPv6 mechanism operating 1358 on IEEE 802.11-OCB link must support strong link asymmetry, spatio- 1359 temporal link quality, fast address resolution and transmission. 1361 IEEE 802.11-OCB strongly differs from other 802.11 systems to operate 1362 outside of the context of a Basic Service Set. This means in 1363 practice that IEEE 802.11-OCB does not rely on a Base Station for all 1364 Basic Service Set management. In particular, IEEE 802.11-OCB shall 1365 not use beacons. Any IPv6 mechanism requiring L2 services from IEEE 1366 802.11 beacons must support an alternative service. 1368 Channel scanning being disabled, IPv6 over IEEE 802.11-OCB must 1369 implement a mechanism for transmitter and receiver to converge to a 1370 common channel. 1372 Authentication not being possible, IPv6 over IEEE 802.11-OCB must 1373 implement an distributed mechanism to authenticate transmitters and 1374 receivers without the support of a DHCP server. 1376 Time synchronization not being available, IPv6 over IEEE 802.11-OCB 1377 must implement a higher layer mechanism for time synchronization 1378 between transmitters and receivers without the support of a NTP 1379 server. 1381 The IEEE 802.11-OCB link being asymmetric, IPv6 over IEEE 802.11-OCB 1382 must disable management mechanisms requesting acknowledgements or 1383 replies. 1385 The IEEE 802.11-OCB link having a short duration time, IPv6 over IEEE 1386 802.11-OCB should implement fast IPv6 mobility management mechanisms. 1388 F.3. Multiple interfaces 1390 There are considerations for 2 or more IEEE 802.11-OCB interface 1391 cards per vehicle. For each vehicle taking part in road traffic, one 1392 IEEE 802.11-OCB interface card could be fully allocated for Non IP 1393 safety-critical communication. Any other IEEE 802.11-OCB may be used 1394 for other type of traffic. 1396 The mode of operation of these other wireless interfaces is not 1397 clearly defined yet. One possibility is to consider each card as an 1398 independent network interface, with a specific MAC Address and a set 1399 of IPv6 addresses. Another possibility is to consider the set of 1400 these wireless interfaces as a single network interface (not 1401 including the IEEE 802.11-OCB interface used by Non IP safety 1402 critical communications). This will require specific logic to 1403 ensure, for example, that packets meant for a vehicle in front are 1404 actually sent by the radio in the front, or that multiple copies of 1405 the same packet received by multiple interfaces are treated as a 1406 single packet. Treating each wireless interface as a separate 1407 network interface pushes such issues to the application layer. 1409 Certain privacy requirements imply that if these multiple interfaces 1410 are represented by many network interface, a single renumbering event 1411 shall cause renumbering of all these interfaces. If one MAC changed 1412 and another stayed constant, external observers would be able to 1413 correlate old and new values, and the privacy benefits of 1414 randomization would be lost. 1416 The privacy requirements of Non IP safety-critical communications 1417 imply that if a change of pseudonyme occurs, renumbering of all other 1418 interfaces shall also occur. 1420 F.4. MAC Address Generation 1422 In 802.11-OCB networks, the MAC addresses may change during well 1423 defined renumbering events. A 'randomized' MAC address has the 1424 following characteristics: 1426 o Bit "Local/Global" set to "locally admninistered". 1428 o Bit "Unicast/Multicast" set to "Unicast". 1430 o The 46 remaining bits are set to a random value, using a random 1431 number generator that meets the requirements of [RFC4086]. 1433 To meet the randomization requirements for the 46 remaining bits, a 1434 hash function may be used. For example, the SHA256 hash function may 1435 be used with input a 256 bit local secret, the "nominal" MAC Address 1436 of the interface, and a representation of the date and time of the 1437 renumbering event. 1439 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode 1441 For information, at the time of writing, this is the list of IEEE 1442 802.11 messages that may be transmitted in OCB mode, i.e. when 1443 dot11OCBActivated is true in a STA: 1445 o The STA may send management frames of subtype Action and, if the 1446 STA maintains a TSF Timer, subtype Timing Advertisement; 1448 o The STA may send control frames, except those of subtype PS-Poll, 1449 CF-End, and CF-End plus CFAck; 1451 o The STA may send data frames of subtype Data, Null, QoS Data, and 1452 QoS Null. 1454 Appendix H. Implementation Status 1456 This section describes an example of an IPv6 Packet captured over a 1457 IEEE 802.11-OCB link. 1459 By way of example we show that there is no modification in the 1460 headers when transmitted over 802.11-OCB networks - they are 1461 transmitted like any other 802.11 and Ethernet packets. 1463 We describe an experiment of capturing an IPv6 packet on an 1464 802.11-OCB link. In topology depicted in Figure 6, the packet is an 1465 IPv6 Router Advertisement. This packet is emitted by a Router on its 1466 802.11-OCB interface. The packet is captured on the Host, using a 1467 network protocol analyzer (e.g. Wireshark); the capture is performed 1468 in two different modes: direct mode and 'monitor' mode. The topology 1469 used during the capture is depicted below. 1471 The packet is captured on the Host. The Host is an IP-OBU containing 1472 an 802.11 interface in format PCI express (an ITRI product). The 1473 kernel runs the ath5k software driver with modifications for OCB 1474 mode. The capture tool is Wireshark. The file format for save and 1475 analyze is 'pcap'. The packet is generated by the Router. The 1476 Router is an IP-RSU (ITRI product). 1478 +--------+ +-------+ 1479 | | 802.11-OCB Link | | 1480 ---| Router |--------------------------------| Host | 1481 | | | | 1482 +--------+ +-------+ 1484 Figure 6: Topology for capturing IP packets on 802.11-OCB 1486 During several capture operations running from a few moments to 1487 several hours, no message relevant to the BSSID contexts were 1488 captured (no Association Request/Response, Authentication Req/Resp, 1489 Beacon). This shows that the operation of 802.11-OCB is outside the 1490 context of a BSSID. 1492 Overall, the captured message is identical with a capture of an IPv6 1493 packet emitted on a 802.11b interface. The contents are precisely 1494 similar. 1496 H.1. Capture in Monitor Mode 1498 The IPv6 RA packet captured in monitor mode is illustrated below. 1499 The radio tap header provides more flexibility for reporting the 1500 characteristics of frames. The Radiotap Header is prepended by this 1501 particular stack and operating system on the Host machine to the RA 1502 packet received from the network (the Radiotap Header is not present 1503 on the air). The implementation-dependent Radiotap Header is useful 1504 for piggybacking PHY information from the chip's registers as data in 1505 a packet understandable by userland applications using Socket 1506 interfaces (the PHY interface can be, for example: power levels, data 1507 rate, ratio of signal to noise). 1509 The packet present on the air is formed by IEEE 802.11 Data Header, 1510 Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. 1512 Radiotap Header v0 1513 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1514 |Header Revision| Header Pad | Header length | 1515 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1516 | Present flags | 1517 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1518 | Data Rate | Pad | 1519 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1521 IEEE 802.11 Data Header 1522 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1523 | Type/Subtype and Frame Ctrl | Duration | 1524 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1525 | Receiver Address... 1526 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1527 ... Receiver Address | Transmitter Address... 1528 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1529 ... Transmitter Address | 1530 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1531 | BSS Id... 1532 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1533 ... BSS Id | Frag Number and Seq Number | 1534 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1536 Logical-Link Control Header 1537 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1538 | DSAP |I| SSAP |C| Control field | Org. code... 1539 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1540 ... Organizational Code | Type | 1541 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1543 IPv6 Base Header 1544 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1545 |Version| Traffic Class | Flow Label | 1546 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1547 | Payload Length | Next Header | Hop Limit | 1548 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1549 | | 1550 + + 1551 | | 1552 + Source Address + 1553 | | 1554 + + 1555 | | 1556 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1557 | | 1558 + + 1559 | | 1560 + Destination Address + 1561 | | 1562 + + 1563 | | 1564 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1566 Router Advertisement 1567 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1568 | Type | Code | Checksum | 1569 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1570 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1571 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1572 | Reachable Time | 1573 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1574 | Retrans Timer | 1575 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1576 | Options ... 1577 +-+-+-+-+-+-+-+-+-+-+-+- 1579 The value of the Data Rate field in the Radiotap header is set to 6 1580 Mb/s. This indicates the rate at which this RA was received. 1582 The value of the Transmitter address in the IEEE 802.11 Data Header 1583 is set to a 48bit value. The value of the destination address is 1584 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS 1585 Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network 1586 protocol analyzer as being "broadcast". The Fragment number and 1587 sequence number fields are together set to 0x90C6. 1589 The value of the Organization Code field in the Logical-Link Control 1590 Header is set to 0x0, recognized as "Encapsulated Ethernet". The 1591 value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise 1592 #86DD), recognized as "IPv6". 1594 A Router Advertisement is periodically sent by the router to 1595 multicast group address ff02::1. It is an icmp packet type 134. The 1596 IPv6 Neighbor Discovery's Router Advertisement message contains an 1597 8-bit field reserved for single-bit flags, as described in [RFC4861]. 1599 The IPv6 header contains the link local address of the router 1600 (source) configured via EUI-64 algorithm, and destination address set 1601 to ff02::1. Recent versions of network protocol analyzers (e.g. 1602 Wireshark) provide additional informations for an IP address, if a 1603 geolocalization database is present. In this example, the 1604 geolocalization database is absent, and the "GeoIP" information is 1605 set to unknown for both source and destination addresses (although 1606 the IPv6 source and destination addresses are set to useful values). 1607 This "GeoIP" can be a useful information to look up the city, 1608 country, AS number, and other information for an IP address. 1610 The Ethernet Type field in the logical-link control header is set to 1611 0x86dd which indicates that the frame transports an IPv6 packet. In 1612 the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 1613 which is the corresponding multicast MAC address. The BSS id is a 1614 broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link 1615 duration between vehicles and the roadside infrastructure, there is 1616 no need in IEEE 802.11-OCB to wait for the completion of association 1617 and authentication procedures before exchanging data. IEEE 1618 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) 1619 and may start communicating as soon as they arrive on the 1620 communication channel. 1622 H.2. Capture in Normal Mode 1624 The same IPv6 Router Advertisement packet described above (monitor 1625 mode) is captured on the Host, in the Normal mode, and depicted 1626 below. 1628 Ethernet II Header 1629 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1630 | Destination... 1631 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1632 ...Destination | Source... 1633 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1634 ...Source | 1635 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1636 | Type | 1637 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1639 IPv6 Base Header 1640 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1641 |Version| Traffic Class | Flow Label | 1642 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1643 | Payload Length | Next Header | Hop Limit | 1644 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1645 | | 1646 + + 1647 | | 1648 + Source Address + 1649 | | 1650 + + 1651 | | 1652 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1653 | | 1654 + + 1655 | | 1656 + Destination Address + 1657 | | 1658 + + 1659 | | 1660 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1662 Router Advertisement 1663 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1664 | Type | Code | Checksum | 1665 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1666 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1667 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1668 | Reachable Time | 1669 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1670 | Retrans Timer | 1671 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1672 | Options ... 1673 +-+-+-+-+-+-+-+-+-+-+-+- 1675 One notices that the Radiotap Header, the IEEE 802.11 Data Header and 1676 the Logical-Link Control Headers are not present. On the other hand, 1677 a new header named Ethernet II Header is present. 1679 The Destination and Source addresses in the Ethernet II header 1680 contain the same values as the fields Receiver Address and 1681 Transmitter Address present in the IEEE 802.11 Data Header in the 1682 "monitor" mode capture. 1684 The value of the Type field in the Ethernet II header is 0x86DD 1685 (recognized as "IPv6"); this value is the same value as the value of 1686 the field Type in the Logical-Link Control Header in the "monitor" 1687 mode capture. 1689 The knowledgeable experimenter will no doubt notice the similarity of 1690 this Ethernet II Header with a capture in normal mode on a pure 1691 Ethernet cable interface. 1693 An Adaptation layer is inserted on top of a pure IEEE 802.11 MAC 1694 layer, in order to adapt packets, before delivering the payload data 1695 to the applications. It adapts 802.11 LLC/MAC headers to Ethernet II 1696 headers. In further detail, this adaptation consists in the 1697 elimination of the Radiotap, 802.11 and LLC headers, and in the 1698 insertion of the Ethernet II header. In this way, IPv6 runs straight 1699 over LLC over the 802.11-OCB MAC layer; this is further confirmed by 1700 the use of the unique Type 0x86DD. 1702 Authors' Addresses 1704 Alexandre Petrescu 1705 CEA, LIST 1706 CEA Saclay 1707 Gif-sur-Yvette , Ile-de-France 91190 1708 France 1710 Phone: +33169089223 1711 Email: Alexandre.Petrescu@cea.fr 1713 Nabil Benamar 1714 Moulay Ismail University 1715 Morocco 1717 Phone: +212670832236 1718 Email: n.benamar@est.umi.ac.ma 1719 Jerome Haerri 1720 Eurecom 1721 Sophia-Antipolis 06904 1722 France 1724 Phone: +33493008134 1725 Email: Jerome.Haerri@eurecom.fr 1727 Jong-Hyouk Lee 1728 Sangmyung University 1729 31, Sangmyeongdae-gil, Dongnam-gu 1730 Cheonan 31066 1731 Republic of Korea 1733 Email: jonghyouk@smu.ac.kr 1735 Thierry Ernst 1736 YoGoKo 1737 France 1739 Email: thierry.ernst@yogoko.fr