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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 19, 2018 Moulay Ismail University 6 J. Haerri 7 Eurecom 8 J. Lee 9 Sangmyung University 10 T. Ernst 11 YoGoKo 12 February 15, 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-17.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 19, 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 4 67 4. IPv6 over 802.11-OCB . . . . . . . . . . . . . . . . . . . . 5 68 4.1. Maximum Transmission Unit (MTU) . . . . . . . . . . . . . 5 69 4.2. Frame Format . . . . . . . . . . . . . . . . . . . . . . 5 70 4.2.1. Ethernet Adaptation Layer . . . . . . . . . . . . . . 5 71 4.3. Link-Local Addresses . . . . . . . . . . . . . . . . . . 8 72 4.4. Address Mapping . . . . . . . . . . . . . . . . . . . . . 8 73 4.4.1. Address Mapping -- Unicast . . . . . . . . . . . . . 8 74 4.4.2. Address Mapping -- Multicast . . . . . . . . . . . . 8 75 4.5. Stateless Autoconfiguration . . . . . . . . . . . . . . . 8 76 4.6. Subnet Structure . . . . . . . . . . . . . . . . . . . . 9 77 5. Security Considerations . . . . . . . . . . . . . . . . . . . 10 78 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 79 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 11 80 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11 81 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 82 9.1. Normative References . . . . . . . . . . . . . . . . . . 12 83 9.2. Informative References . . . . . . . . . . . . . . . . . 14 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 Appendix I. Extra Terminology . . . . . . . . . . . . . . . . . 37 101 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 38 103 1. Introduction 105 This document describes the transmission of IPv6 packets on IEEE Std 106 802.11-OCB networks [IEEE-802.11-2016] (a.k.a "802.11p" see 107 Appendix B). This involves the layering of IPv6 networking on top of 108 the IEEE 802.11 MAC layer, with an LLC layer. Compared to running 109 IPv6 over the Ethernet MAC layer, there is no modification expected 110 to IEEE Std 802.11 MAC and Logical Link sublayers: IPv6 works fine 111 directly over 802.11-OCB too, with an LLC layer. 113 The IPv6 network layer operates on 802.11-OCB in the same manner as 114 operating on Ethernet, but there are two kinds of exceptions: 116 o Exceptions due to different operation of IPv6 network layer on 117 802.11 than on Ethernet. To satisfy these exceptions, this 118 document describes an Ethernet Adaptation Layer between Ethernet 119 headers and 802.11 headers. The Ethernet Adaptation Layer is 120 described Section 4.2.1. The operation of IP on Ethernet is 121 described in [RFC1042], [RFC2464] and 122 [I-D.hinden-6man-rfc2464bis]. 124 o Exceptions due to the OCB nature of 802.11-OCB compared to 802.11. 125 This has impacts on security, privacy, subnet structure and 126 handover behaviour. For security and privacy recommendations see 127 Section 5 and Section 4.5. The subnet structure is described in 128 Section 4.6. The handover behaviour on OCB links is not described 129 in this document. 131 In the published literature, many documents describe aspects and 132 problems related to running IPv6 over 802.11-OCB: 133 [I-D.ietf-ipwave-vehicular-networking-survey]. 135 2. Terminology 137 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 138 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 139 document are to be interpreted as described in RFC 2119 [RFC2119]. 141 IP-OBU (Internet Protocol On-Board Unit): an IP-OBU is a computer 142 situated in a vehicle such as an automobile, bicycle, or similar. It 143 has at least one IP interface that runs in mode OCB of 802.11, and 144 that has an "OBU" transceiver. See the definition of the term "OBU" 145 in section Appendix I. 147 IP-RSU (IP Road-Side Unit): an IP-RSU is situated along the road. An 148 IP-RSU has at least two distinct IP-enabled interfaces; at least one 149 interface is operated in mode OCB of IEEE 802.11 and is IP-enabled. 150 An IP-RSU is similar to a Wireless Termination Point (WTP), as 151 defined in [RFC5415], or an Access Point (AP), as defined in IEEE 152 documents, or an Access Network Router (ANR) defined in [RFC3753], 153 with one key particularity: the wireless PHY/MAC layer of at least 154 one of its IP-enabled interfaces is configured to operate in 155 802.11-OCB mode. The IP-RSU communicates with the IP-OBU in the 156 vehicle over 802.11 wireless link operating in OCB mode. 158 OCB (outside the context of a basic service set - BSS): A mode of 159 operation in which a STA is not a member of a BSS and does not 160 utilize IEEE Std 802.11 authentication, association, or data 161 confidentiality. 163 802.11-OCB: mode specified in IEEE Std 802.11-2016 when the MIB 164 attribute dot11OCBActivited is true. The OCB mode requires 165 transmission of QoS data frames (IEEE Std 802.11e), half-clocked 166 operation (IEEE Std 802.11j), and use of 5.9 GHz frequency band. 167 Nota: any implementation should comply with standards and regulations 168 set in the different countries for using that frequency band. 170 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 172 The IEEE 802.11-OCB Networks are used for vehicular communications, 173 as 'Wireless Access in Vehicular Environments'. The IP communication 174 scenarios for these environments have been described in several 175 documents; in particular, we refer the reader to 176 [I-D.ietf-ipwave-vehicular-networking-survey], that lists some 177 scenarios and requirements for IP in Intelligent Transportation 178 Systems. 180 The link model is the following: STA --- 802.11-OCB --- STA. In 181 vehicular networks, STAs can be IP-RSUs and/or IP-OBUs. While 182 802.11-OCB is clearly specified, and the use of IPv6 over such link 183 is not radically new, the operating environment (vehicular networks) 184 brings in new perspectives. 186 The mechanisms for forming and terminating, discovering, peering and 187 mobility management for 802.11-OCB links are not described in this 188 document. 190 4. IPv6 over 802.11-OCB 192 4.1. Maximum Transmission Unit (MTU) 194 The default MTU for IP packets on 802.11-OCB MUST be 1500 octets. It 195 is the same value as IPv6 packets on Ethernet links, as specified in 196 [RFC2464]. This value of the MTU respects the recommendation that 197 every link on the Internet must have a minimum MTU of 1280 octets 198 (stated in [RFC8200], and the recommendations therein, especially 199 with respect to fragmentation). If IPv6 packets of size larger than 200 1500 bytes are sent on an 802.11-OCB interface card then the IP stack 201 MUST fragment. In case there are IP fragments, the field "Sequence 202 number" of the 802.11 Data header containing the IP fragment field is 203 increased. 205 Non-IP packets such as WAVE Short Message Protocol (WSMP) can be 206 delivered on 802.11-OCB links. Specifications of these packets are 207 out of scope of this document, and do not impose any limit on the MTU 208 size, allowing an arbitrary number of 'containers'. Non-IP packets 209 such as ETSI GeoNetworking packets have an MTU of 1492 bytes. The 210 operation of IPv6 over GeoNetworking is specified at 211 [ETSI-IPv6-GeoNetworking]. 213 4.2. Frame Format 215 IP packets are transmitted over 802.11-OCB as standard Ethernet 216 packets. As with all 802.11 frames, an Ethernet adaptation layer is 217 used with 802.11-OCB as well. This Ethernet Adaptation Layer 218 performing 802.11-to-Ethernet is described in Section 4.2.1. The 219 Ethernet Type code (EtherType) for IPv6 MUST be 0x86DD (hexadecimal 220 86DD, or otherwise #86DD). 222 The Frame format for transmitting IPv6 on 802.11-OCB networks is the 223 same as transmitting IPv6 on Ethernet networks, and is described in 224 section 3 of [RFC2464]. 226 1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1 227 is the binary representation of the EtherType value 0x86DD. 229 4.2.1. Ethernet Adaptation Layer 231 An 'adaptation' layer is inserted between a MAC layer and the 232 Networking layer. This is used to transform some parameters between 233 their form expected by the IP stack and the form provided by the MAC 234 layer. 236 An Ethernet Adaptation Layer makes an 802.11 MAC look to IP 237 Networking layer as a more traditional Ethernet layer. At reception, 238 this layer takes as input the IEEE 802.11 Data Header and the 239 Logical-Link Layer Control Header and produces an Ethernet II Header. 240 At sending, the reverse operation is performed. 242 The operation of the Ethernet Adaptation Layer is depicted by the 243 double arrow in Figure 1. 245 +--------------------+------------+-------------+---------+-----------+ 246 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer| 247 +--------------------+------------+-------------+---------+-----------+ 248 \ / \ / 249 ----------------------------- -------- 250 \---------------------------------------------/ 251 ^ 252 | 253 802.11-to-Ethernet Adaptation Layer 254 | 255 v 256 +---------------------+-------------+---------+ 257 | Ethernet II Header | IPv6 Header | Payload | 258 +---------------------+-------------+---------+ 260 Figure 1: Operation of the Ethernet Adaptation Layer 262 The Receiver and Transmitter Address fields in the 802.11 Data Header 263 MUST contain the same values as the Destination and the Source 264 Address fields in the Ethernet II Header, respectively. The value of 265 the Type field in the LLC Header MUST be the same as the value of the 266 Type field in the Ethernet II Header. 268 The ".11 Trailer" contains solely a 4-byte Frame Check Sequence. 270 Additionally, the Ethernet Adaptation Layer performs operations in 271 relation to IP fragmentation and MTU. One of these operations is 272 briefly described in Section 4.1. 274 In OCB mode, IPv6 packets MAY be transmitted either as "IEEE 802.11 275 Data" or alternatively as "IEEE 802.11 QoS Data", as illustrated in 276 Figure 2. 278 +--------------------+-------------+-------------+---------+-----------+ 279 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer| 280 +--------------------+-------------+-------------+---------+-----------+ 282 or 284 +--------------------+-------------+-------------+---------+-----------+ 285 | 802.11 QoS Data Hdr| LLC Header | IPv6 Header | Payload |.11 Trailer| 286 +--------------------+-------------+-------------+---------+-----------+ 288 Figure 2: 802.11 Data Header or 802.11 QoS Data Header 290 The distinction between the two formats is given by the value of the 291 field "Type/Subtype". The value of the field "Type/Subtype" in the 292 802.11 Data header is 0x0020. The value of the field "Type/Subtype" 293 in the 802.11 QoS header is 0x0028. 295 The mapping between qos-related fields in the IPv6 header (e.g. 296 "Traffic Class", "Flow label") and fields in the "802.11 QoS Data 297 Header" (e.g. "QoS Control") are not specified in this document. 298 Guidance for a potential mapping is provided in 299 [I-D.ietf-tsvwg-ieee-802-11], although it is not specific to OCB 300 mode. 302 The placement of IPv6 networking layer on Ethernet Adaptation Layer 303 is illustrated in Figure 3. 305 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 306 | IPv6 | 307 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 308 | Ethernet Adaptation Layer | 309 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 310 | 802.11 MAC | 311 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 312 | 802.11 PHY | 313 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 315 Figure 3: Ethernet Adaptation Layer stacked with other layers 317 (in the above figure, a 802.11 profile is represented; this is used 318 also for 802.11 OCB profile.) 320 Other alternative views of layering are EtherType Protocol 321 Discrimination (EPD), see Appendix E, and SNAP see [RFC1042]. 323 4.3. Link-Local Addresses 325 The link-local address of an 802.11-OCB interface is formed in the 326 same manner as on an Ethernet interface. This manner is described in 327 section 5 of [RFC2464]. Additionally, if stable identifiers are 328 needed, it is recommended to follow the Recommendation on Stable IPv6 329 Interface Identifiers [RFC8064]. Additionally, if semantically 330 opaque Interface Identifiers are needed, a potential method for 331 generating semantically opaque Interface Identifiers with IPv6 332 Stateless Address Autoconfiguration is given in [RFC7217]. 334 4.4. Address Mapping 336 For unicast as for multicast, there is no change from the unicast and 337 multicast address mapping format of Ethernet interfaces, as defined 338 by sections 6 and 7 of [RFC2464]. 340 4.4.1. Address Mapping -- Unicast 342 The procedure for mapping IPv6 unicast addresses into Ethernet link- 343 layer addresses is described in [RFC4861]. 345 4.4.2. Address Mapping -- Multicast 347 The multicast address mapping is performed according to the method 348 specified in section 7 of [RFC2464]. The meaning of the value "3333" 349 mentioned in that section 7 of [RFC2464] is defined in section 2.3.1 350 of [RFC7042]. 352 Transmitting IPv6 packets to multicast destinations over 802.11 links 353 proved to have some performance issues 354 [I-D.perkins-intarea-multicast-ieee802]. These issues may be 355 exacerbated in OCB mode. Solutions for these problems should 356 consider the OCB mode of operation. 358 4.5. Stateless Autoconfiguration 360 The Interface Identifier for an 802.11-OCB interface is formed using 361 the same rules as the Interface Identifier for an Ethernet interface; 362 this is described in section 4 of [RFC2464]. No changes are needed, 363 but some care must be taken when considering the use of the Stateless 364 Address Auto-Configuration procedure. 366 The bits in the interface identifier have no generic meaning and the 367 identifier should be treated as an opaque value. The bits 368 'Universal' and 'Group' in the identifier of an 802.11-OCB interface 369 are significant, as this is an IEEE link-layer address. The details 370 of this significance are described in [RFC7136]. 372 As with all Ethernet and 802.11 interface identifiers ([RFC7721]), 373 the identifier of an 802.11-OCB interface may involve privacy, MAC 374 address spoofing and IP address hijacking risks. A vehicle embarking 375 an OBU or an IP-OBU whose egress interface is 802.11-OCB may expose 376 itself to eavesdropping and subsequent correlation of data; this may 377 reveal data considered private by the vehicle owner; there is a risk 378 of being tracked; see the privacy considerations described in 379 Appendix F. 381 If stable Interface Identifiers are needed in order to form IPv6 382 addresses on 802.11-OCB links, it is recommended to follow the 383 recommendation in [RFC8064]. Additionally, if semantically opaque 384 Interface Identifiers are needed, a potential method for generating 385 semantically opaque Interface Identifiers with IPv6 Stateless Address 386 Autoconfiguration is given in [RFC7217]. 388 4.6. Subnet Structure 390 A subnet is formed by the external 802.11-OCB interfaces of vehicles 391 that are in close range (not their on-board interfaces). This 392 ephemeral subnet structure is strongly influenced by the mobility of 393 vehicles: the 802.11 hidden node effects appear. On another hand, 394 the structure of the internal subnets in each car is relatively 395 stable. 397 The 802.11 networks in OCB mode may be considered as 'ad-hoc' 398 networks. The addressing model for such networks is described in 399 [RFC5889]. 401 An addressing model involves several types of addresses, like 402 Globally-unique Addresses (GUA), Link-Local Addresses (LL) and Unique 403 Local Addresses (ULA). The subnet structure in 'ad-hoc' networks may 404 have characteristics that lead to difficulty of using GUAs derived 405 from a received prefix, but the LL addresses may be easier to use 406 since the prefix is constant. 408 The operation of the Neighbor Discovery protocol (ND) over 802.11 OCB 409 links is different than over 802.11 links. In OCB, the link layer 410 does not ensure that all associated members receive all messages, 411 because there is no association operation. The operation of ND over 412 802.11 OCB is not specified in this document. 414 The operation of the Mobile IPv6 protocol over 802.11 OCB links is 415 different than on other links. The Movement Detection operation 416 (section 11.5.1 of [RFC6275]) can not rely on Neighbor Unreachability 417 Detection operation of the Neighbor Discovery protocol, for the 418 reason mentioned in the previous paragraph. Also, the 802.11 OCB 419 link layer is not a lower layer that can provide an indication that a 420 link layer handover has occured. The operation of the Mobile IPv6 421 protocol over 802.11 OCB is not specified in this document. 423 5. Security Considerations 425 Any security mechanism at the IP layer or above that may be carried 426 out for the general case of IPv6 may also be carried out for IPv6 427 operating over 802.11-OCB. 429 The OCB operation is stripped off of all existing 802.11 link-layer 430 security mechanisms. There is no encryption applied below the 431 network layer running on 802.11-OCB. At application layer, the IEEE 432 1609.2 document [IEEE-1609.2] does provide security services for 433 certain applications to use; application-layer mechanisms are out-of- 434 scope of this document. On another hand, a security mechanism 435 provided at networking layer, such as IPsec [RFC4301], may provide 436 data security protection to a wider range of applications. 438 802.11-OCB does not provide any cryptographic protection, because it 439 operates outside the context of a BSS (no Association Request/ 440 Response, no Challenge messages). Any attacker can therefore just 441 sit in the near range of vehicles, sniff the network (just set the 442 interface card's frequency to the proper range) and perform attacks 443 without needing to physically break any wall. Such a link is less 444 protected than commonly used links (wired link or protected 802.11). 446 The potential attack vectors are: MAC address spoofing, IP address 447 and session hijacking and privacy violation. 449 Within the IPsec Security Architecture [RFC4301], the IPsec AH and 450 ESP headers [RFC4302] and [RFC4303] respectively, its multicast 451 extensions [RFC5374], HTTPS [RFC2818] and SeND [RFC3971] protocols 452 can be used to protect communications. Further, the assistance of 453 proper Public Key Infrastructure (PKI) protocols [RFC4210] is 454 necessary to establish credentials. More IETF protocols are 455 available in the toolbox of the IP security protocol designer. 456 Certain ETSI protocols related to security protocols in Intelligent 457 Transportation Systems are described in [ETSI-sec-archi]. 459 As with all Ethernet and 802.11 interface identifiers, there may 460 exist privacy risks in the use of 802.11-OCB interface identifiers. 461 Moreover, in outdoors vehicular settings, the privacy risks are more 462 important than in indoors settings. New risks are induced by the 463 possibility of attacker sniffers deployed along routes which listen 464 for IP packets of vehicles passing by. For this reason, in the 465 802.11-OCB deployments, there is a strong necessity to use protection 466 tools such as dynamically changing MAC addresses. This may help 467 mitigate privacy risks to a certain level. On another hand, it may 468 have an impact in the way typical IPv6 address auto-configuration is 469 performed for vehicles (SLAAC would rely on MAC addresses and would 470 hence dynamically change the affected IP address), in the way the 471 IPv6 Privacy addresses were used, and other effects. 473 6. IANA Considerations 475 No request to IANA. 477 7. Contributors 479 Christian Huitema, Tony Li. 481 Romain Kuntz contributed extensively about IPv6 handovers between 482 links running outside the context of a BSS (802.11-OCB links). 484 Tim Leinmueller contributed the idea of the use of IPv6 over 485 802.11-OCB for distribution of certificates. 487 Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey 488 Voronov provided significant feedback on the experience of using IP 489 messages over 802.11-OCB in initial trials. 491 Michelle Wetterwald contributed extensively the MTU discussion, 492 offered the ETSI ITS perspective, and reviewed other parts of the 493 document. 495 8. Acknowledgements 497 The authors would like to thank Witold Klaudel, Ryuji Wakikawa, 498 Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan 499 Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray 500 Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, 501 Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne, 502 Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark, 503 Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley, Sandra 504 Cespedes, Mariano Falcitelli, Sri Gundavelli, Abdussalam Baryun, 505 Margaret Cullen, Erik Kline, Carlos Jesus Bernardos Cano and William 506 Whyte. Their valuable comments clarified particular issues and 507 generally helped to improve the document. 509 Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB 510 drivers for linux and described how. 512 For the multicast discussion, the authors would like to thank Owen 513 DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and 514 participants to discussions in network working groups. 516 The authors would like to thank participants to the Birds-of- 517 a-Feather "Intelligent Transportation Systems" meetings held at IETF 518 in 2016. 520 9. References 522 9.1. Normative References 524 [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission 525 of IP datagrams over IEEE 802 networks", STD 43, RFC 1042, 526 DOI 10.17487/RFC1042, February 1988, 527 . 529 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 530 Requirement Levels", BCP 14, RFC 2119, 531 DOI 10.17487/RFC2119, March 1997, 532 . 534 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 535 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 536 . 538 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 539 DOI 10.17487/RFC2818, May 2000, 540 . 542 [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related 543 Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, 544 . 546 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 547 "SEcure Neighbor Discovery (SEND)", RFC 3971, 548 DOI 10.17487/RFC3971, March 2005, 549 . 551 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 552 "Randomness Requirements for Security", BCP 106, RFC 4086, 553 DOI 10.17487/RFC4086, June 2005, 554 . 556 [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, 557 "Internet X.509 Public Key Infrastructure Certificate 558 Management Protocol (CMP)", RFC 4210, 559 DOI 10.17487/RFC4210, September 2005, 560 . 562 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 563 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 564 December 2005, . 566 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 567 DOI 10.17487/RFC4302, December 2005, 568 . 570 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 571 RFC 4303, DOI 10.17487/RFC4303, December 2005, 572 . 574 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 575 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 576 DOI 10.17487/RFC4861, September 2007, 577 . 579 [RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast 580 Extensions to the Security Architecture for the Internet 581 Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008, 582 . 584 [RFC5415] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, 585 Ed., "Control And Provisioning of Wireless Access Points 586 (CAPWAP) Protocol Specification", RFC 5415, 587 DOI 10.17487/RFC5415, March 2009, 588 . 590 [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing 591 Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889, 592 September 2010, . 594 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 595 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 596 2011, . 598 [RFC7042] Eastlake 3rd, D. and J. Abley, "IANA Considerations and 599 IETF Protocol and Documentation Usage for IEEE 802 600 Parameters", BCP 141, RFC 7042, DOI 10.17487/RFC7042, 601 October 2013, . 603 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 604 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 605 February 2014, . 607 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 608 Interface Identifiers with IPv6 Stateless Address 609 Autoconfiguration (SLAAC)", RFC 7217, 610 DOI 10.17487/RFC7217, April 2014, 611 . 613 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 614 Considerations for IPv6 Address Generation Mechanisms", 615 RFC 7721, DOI 10.17487/RFC7721, March 2016, 616 . 618 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 619 "Recommendation on Stable IPv6 Interface Identifiers", 620 RFC 8064, DOI 10.17487/RFC8064, February 2017, 621 . 623 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 624 (IPv6) Specification", STD 86, RFC 8200, 625 DOI 10.17487/RFC8200, July 2017, 626 . 628 9.2. Informative References 630 [ETSI-IPv6-GeoNetworking] 631 "ETSI EN 302 636-6-1 v1.2.1 (2014-05), ETSI, European 632 Standard, Intelligent Transportation Systems (ITS); 633 Vehicular Communications; Geonetworking; Part 6: Internet 634 Integration; Sub-part 1: Transmission of IPv6 Packets over 635 Geonetworking Protocols. Downloaded on September 9th, 636 2017, freely available from ETSI website at URL 637 http://www.etsi.org/deliver/ 638 etsi_en/302600_302699/30263601/01.02.01_60/ 639 en_30263601v010201p.pdf". 641 [ETSI-sec-archi] 642 "ETSI TS 102 940 V1.2.1 (2016-11), ETSI Technical 643 Specification, Intelligent Transport Systems (ITS); 644 Security; ITS communications security architecture and 645 security management, November 2016. Downloaded on 646 September 9th, 2017, freely available from ETSI website at 647 URL http://www.etsi.org/deliver/ 648 etsi_ts/102900_102999/102940/01.02.01_60/ 649 ts_102940v010201p.pdf". 651 [I-D.hinden-6man-rfc2464bis] 652 Crawford, M. and R. Hinden, "Transmission of IPv6 Packets 653 over Ethernet Networks", draft-hinden-6man-rfc2464bis-02 654 (work in progress), March 2017. 656 [I-D.ietf-ipwave-vehicular-networking-survey] 657 Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M. 658 Wetterwald, "Survey on IP-based Vehicular Networking for 659 Intelligent Transportation Systems", draft-ietf-ipwave- 660 vehicular-networking-survey-00 (work in progress), July 661 2017. 663 [I-D.ietf-tsvwg-ieee-802-11] 664 Szigeti, T., Henry, J., and F. Baker, "Diffserv to IEEE 665 802.11 Mapping", draft-ietf-tsvwg-ieee-802-11-11 (work in 666 progress), December 2017. 668 [I-D.perkins-intarea-multicast-ieee802] 669 Perkins, C., Stanley, D., Kumari, W., and J. Zuniga, 670 "Multicast Considerations over IEEE 802 Wireless Media", 671 draft-perkins-intarea-multicast-ieee802-03 (work in 672 progress), July 2017. 674 [IEEE-1609.2] 675 "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access 676 in Vehicular Environments (WAVE) -- Security Services for 677 Applications and Management Messages. Example URL 678 http://ieeexplore.ieee.org/document/7426684/ accessed on 679 August 17th, 2017.". 681 [IEEE-1609.3] 682 "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access 683 in Vehicular Environments (WAVE) -- Networking Services. 684 Example URL http://ieeexplore.ieee.org/document/7458115/ 685 accessed on August 17th, 2017.". 687 [IEEE-1609.4] 688 "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access 689 in Vehicular Environments (WAVE) -- Multi-Channel 690 Operation. Example URL 691 http://ieeexplore.ieee.org/document/7435228/ accessed on 692 August 17th, 2017.". 694 [IEEE-802.11-2016] 695 "IEEE Standard 802.11-2016 - IEEE Standard for Information 696 Technology - Telecommunications and information exchange 697 between systems Local and metropolitan area networks - 698 Specific requirements - Part 11: Wireless LAN Medium 699 Access Control (MAC) and Physical Layer (PHY) 700 Specifications. Status - Active Standard. Description 701 retrieved freely on September 12th, 2017, at URL 702 https://standards.ieee.org/findstds/ 703 standard/802.11-2016.html". 705 [IEEE-802.11p-2010] 706 "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information 707 Technology - Telecommunications and information exchange 708 between systems - Local and metropolitan area networks - 709 Specific requirements, Part 11: Wireless LAN Medium Access 710 Control (MAC) and Physical Layer (PHY) Specifications, 711 Amendment 6: Wireless Access in Vehicular Environments; 712 document freely available at URL 713 http://standards.ieee.org/getieee802/ 714 download/802.11p-2010.pdf retrieved on September 20th, 715 2013.". 717 Appendix A. ChangeLog 719 The changes are listed in reverse chronological order, most recent 720 changes appearing at the top of the list. 722 From draft-ietf-ipwave-ipv6-over-80211ocb-16 to draft-ietf-ipwave- 723 ipv6-over-80211ocb-17 725 o Susbtituted "MUST be increased" to "is increased" in the MTU 726 section, about fragmentation. 728 From draft-ietf-ipwave-ipv6-over-80211ocb-15 to draft-ietf-ipwave- 729 ipv6-over-80211ocb-16 731 o Removed the definition of the 'WiFi' term and its occurences. 732 Clarified a phrase that used it in Appendix C "Aspects introduced 733 by the OCB mode to 802.11". 735 o Added more normative words: MUST be 0x86DD, MUST fragment if size 736 larger than MTU, Sequence number in 802.11 Data header MUST be 737 increased. 739 From draft-ietf-ipwave-ipv6-over-80211ocb-14 to draft-ietf-ipwave- 740 ipv6-over-80211ocb-15 742 o Added normative term MUST in two places in section "Ethernet 743 Adaptation Layer". 745 From draft-ietf-ipwave-ipv6-over-80211ocb-13 to draft-ietf-ipwave- 746 ipv6-over-80211ocb-14 748 o Created a new Appendix titled "Extra Terminology" that contains 749 terms DSRC, DSRCS, OBU, RSU as defined outside IETF. Some of them 750 are used in the main Terminology section. 752 o Added two paragraphs explaining that ND and Mobile IPv6 have 753 problems working over 802.11 OCB, yet their adaptations is not 754 specified in this document. 756 From draft-ietf-ipwave-ipv6-over-80211ocb-12 to draft-ietf-ipwave- 757 ipv6-over-80211ocb-13 759 o Substituted "IP-OBU" for "OBRU", and "IP-RSU" for "RSRU" 760 throughout and improved OBU-related definitions in the Terminology 761 section. 763 From draft-ietf-ipwave-ipv6-over-80211ocb-11 to draft-ietf-ipwave- 764 ipv6-over-80211ocb-12 766 o Improved the appendix about "MAC Address Generation" by expressing 767 the technique to be an optional suggestion, not a mandatory 768 mechanism. 770 From draft-ietf-ipwave-ipv6-over-80211ocb-10 to draft-ietf-ipwave- 771 ipv6-over-80211ocb-11 773 o Shortened the paragraph on forming/terminating 802.11-OCB links. 775 o Moved the draft tsvwg-ieee-802-11 to Informative References. 777 From draft-ietf-ipwave-ipv6-over-80211ocb-09 to draft-ietf-ipwave- 778 ipv6-over-80211ocb-10 780 o Removed text requesting a new Group ID for multicast for OCB. 782 o Added a clarification of the meaning of value "3333" in the 783 section Address Mapping -- Multicast. 785 o Added note clarifying that in Europe the regional authority is not 786 ETSI, but "ECC/CEPT based on ENs from ETSI". 788 o Added note stating that the manner in which two STAtions set their 789 communication channel is not described in this document. 791 o Added a time qualifier to state that the "each node is represented 792 uniquely at a certain point in time." 794 o Removed text "This section may need to be moved" (the "Reliability 795 Requirements" section). This section stays there at this time. 797 o In the term definition "802.11-OCB" added a note stating that "any 798 implementation should comply with standards and regulations set in 799 the different countries for using that frequency band." 801 o In the RSU term definition, added a sentence explaining the 802 difference between RSU and RSRU: in terms of number of interfaces 803 and IP forwarding. 805 o Replaced "with at least two IP interfaces" with "with at least two 806 real or virtual IP interfaces". 808 o Added a term in the Terminology for "OBU". However the definition 809 is left empty, as this term is defined outside IETF. 811 o Added a clarification that it is an OBU or an OBRU in this phrase 812 "A vehicle embarking an OBU or an OBRU". 814 o Checked the entire document for a consistent use of terms OBU and 815 OBRU. 817 o Added note saying that "'p' is a letter identifying the 818 Ammendment". 820 o Substituted lower case for capitals SHALL or MUST in the 821 Appendices. 823 o Added reference to RFC7042, helpful in the 3333 explanation. 824 Removed reference to individual submission draft-petrescu-its- 825 scenario-reqs and added reference to draft-ietf-ipwave-vehicular- 826 networking-survey. 828 o Added figure captions, figure numbers, and references to figure 829 numbers instead of 'below'. Replaced "section Section" with 830 "section" throughout. 832 o Minor typographical errors. 834 From draft-ietf-ipwave-ipv6-over-80211ocb-08 to draft-ietf-ipwave- 835 ipv6-over-80211ocb-09 837 o Significantly shortened the Address Mapping sections, by text 838 copied from RFC2464, and rather referring to it. 840 o Moved the EPD description to an Appendix on its own. 842 o Shortened the Introduction and the Abstract. 844 o Moved the tutorial section of OCB mode introduced to .11, into an 845 appendix. 847 o Removed the statement that suggests that for routing purposes a 848 prefix exchange mechanism could be needed. 850 o Removed refs to RFC3963, RFC4429 and RFC6775; these are about ND, 851 MIP/NEMO and oDAD; they were referred in the handover discussion 852 section, which is out. 854 o Updated a reference from individual submission to now a WG item in 855 IPWAVE: the survey document. 857 o Added term definition for WiFi. 859 o Updated the authorship and expanded the Contributors section. 861 o Corrected typographical errors. 863 From draft-ietf-ipwave-ipv6-over-80211ocb-07 to draft-ietf-ipwave- 864 ipv6-over-80211ocb-08 866 o Removed the per-channel IPv6 prohibition text. 868 o Corrected typographical errors. 870 From draft-ietf-ipwave-ipv6-over-80211ocb-06 to draft-ietf-ipwave- 871 ipv6-over-80211ocb-07 873 o Added new terms: OBRU and RSRU ('R' for Router). Refined the 874 existing terms RSU and OBU, which are no longer used throughout 875 the document. 877 o Improved definition of term "802.11-OCB". 879 o Clarified that OCB does not "strip" security, but that the 880 operation in OCB mode is "stripped off of all .11 security". 882 o Clarified that theoretical OCB bandwidth speed is 54mbits, but 883 that a commonly observed bandwidth in IP-over-OCB is 12mbit/s. 885 o Corrected typographical errors, and improved some phrasing. 887 From draft-ietf-ipwave-ipv6-over-80211ocb-05 to draft-ietf-ipwave- 888 ipv6-over-80211ocb-06 890 o Updated references of 802.11-OCB document from -2012 to the IEEE 891 802.11-2016. 893 o In the LL address section, and in SLAAC section, added references 894 to 7217 opaque IIDs and 8064 stable IIDs. 896 From draft-ietf-ipwave-ipv6-over-80211ocb-04 to draft-ietf-ipwave- 897 ipv6-over-80211ocb-05 898 o Lengthened the title and cleanded the abstract. 900 o Added text suggesting LLs may be easy to use on OCB, rather than 901 GUAs based on received prefix. 903 o Added the risks of spoofing and hijacking. 905 o Removed the text speculation on adoption of the TSA message. 907 o Clarified that the ND protocol is used. 909 o Clarified what it means "No association needed". 911 o Added some text about how two STAs discover each other. 913 o Added mention of external (OCB) and internal network (stable), in 914 the subnet structure section. 916 o Added phrase explaining that both .11 Data and .11 QoS Data 917 headers are currently being used, and may be used in the future. 919 o Moved the packet capture example into an Appendix Implementation 920 Status. 922 o Suggested moving the reliability requirements appendix out into 923 another document. 925 o Added a IANA Consiserations section, with content, requesting for 926 a new multicast group "all OCB interfaces". 928 o Added new OBU term, improved the RSU term definition, removed the 929 ETTC term, replaced more occurences of 802.11p, 802.11 OCB with 930 802.11-OCB. 932 o References: 934 * Added an informational reference to ETSI's IPv6-over- 935 GeoNetworking. 937 * Added more references to IETF and ETSI security protocols. 939 * Updated some references from I-D to RFC, and from old RFC to 940 new RFC numbers. 942 * Added reference to multicast extensions to IPsec architecture 943 RFC. 945 * Added a reference to 2464-bis. 947 * Removed FCC informative references, because not used. 949 o Updated the affiliation of one author. 951 o Reformulation of some phrases for better readability, and 952 correction of typographical errors. 954 From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave- 955 ipv6-over-80211ocb-04 957 o Removed a few informative references pointing to Dx draft IEEE 958 1609 documents. 960 o Removed outdated informative references to ETSI documents. 962 o Added citations to IEEE 1609.2, .3 and .4-2016. 964 o Minor textual issues. 966 From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave- 967 ipv6-over-80211ocb-03 969 o Keep the previous text on multiple addresses, so remove talk about 970 MIP6, NEMOv6 and MCoA. 972 o Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon. 974 o Clarified the figure showing Infrastructure mode and OCB mode side 975 by side. 977 o Added a reference to the IP Security Architecture RFC. 979 o Detailed the IPv6-per-channel prohibition paragraph which reflects 980 the discussion at the last IETF IPWAVE WG meeting. 982 o Added section "Address Mapping -- Unicast". 984 o Added the ".11 Trailer" to pictures of 802.11 frames. 986 o Added text about SNAP carrying the Ethertype. 988 o New RSU definition allowing for it be both a Router and not 989 necessarily a Router some times. 991 o Minor textual issues. 993 From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave- 994 ipv6-over-80211ocb-02 995 o Replaced almost all occurences of 802.11p with 802.11-OCB, leaving 996 only when explanation of evolution was necessary. 998 o Shortened by removing parameter details from a paragraph in the 999 Introduction. 1001 o Moved a reference from Normative to Informative. 1003 o Added text in intro clarifying there is no handover spec at IEEE, 1004 and that 1609.2 does provide security services. 1006 o Named the contents the fields of the EthernetII header (including 1007 the Ethertype bitstring). 1009 o Improved relationship between two paragraphs describing the 1010 increase of the Sequence Number in 802.11 header upon IP 1011 fragmentation. 1013 o Added brief clarification of "tracking". 1015 From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave- 1016 ipv6-over-80211ocb-01 1018 o Introduced message exchange diagram illustrating differences 1019 between 802.11 and 802.11 in OCB mode. 1021 o Introduced an appendix listing for information the set of 802.11 1022 messages that may be transmitted in OCB mode. 1024 o Removed appendix sections "Privacy Requirements", "Authentication 1025 Requirements" and "Security Certificate Generation". 1027 o Removed appendix section "Non IP Communications". 1029 o Introductory phrase in the Security Considerations section. 1031 o Improved the definition of "OCB". 1033 o Introduced theoretical stacked layers about IPv6 and IEEE layers 1034 including EPD. 1036 o Removed the appendix describing the details of prohibiting IPv6 on 1037 certain channels relevant to 802.11-OCB. 1039 o Added a brief reference in the privacy text about a precise clause 1040 in IEEE 1609.3 and .4. 1042 o Clarified the definition of a Road Side Unit. 1044 o Removed the discussion about security of WSA (because is non-IP). 1046 o Removed mentioning of the GeoNetworking discussion. 1048 o Moved references to scientific articles to a separate 'overview' 1049 draft, and referred to it. 1051 Appendix B. 802.11p 1053 The term "802.11p" is an earlier definition. The behaviour of 1054 "802.11p" networks is rolled in the document IEEE Std 802.11-2016. 1055 In that document the term 802.11p disappears. Instead, each 802.11p 1056 feature is conditioned by the Management Information Base (MIB) 1057 attribute "OCBActivated". Whenever OCBActivated is set to true the 1058 IEEE Std 802.11 OCB state is activated. For example, an 802.11 1059 STAtion operating outside the context of a basic service set has the 1060 OCBActivated flag set. Such a station, when it has the flag set, 1061 uses a BSS identifier equal to ff:ff:ff:ff:ff:ff. 1063 Appendix C. Aspects introduced by the OCB mode to 802.11 1065 In the IEEE 802.11-OCB mode, all nodes in the wireless range can 1066 directly communicate with each other without involving authentication 1067 or association procedures. At link layer, it is necessary to set the 1068 same channel number (or frequency) on two stations that need to 1069 communicate with each other. The manner in which stations set their 1070 channel number is not specified in this document. Stations STA1 and 1071 STA2 can exchange IP packets if they are set on the same channel. At 1072 IP layer, they then discover each other by using the IPv6 Neighbor 1073 Discovery protocol. 1075 Briefly, the IEEE 802.11-OCB mode has the following properties: 1077 o The use by each node of a 'wildcard' BSSID (i.e., each bit of the 1078 BSSID is set to 1) 1080 o No IEEE 802.11 Beacon frames are transmitted 1082 o No authentication is required in order to be able to communicate 1084 o No association is needed in order to be able to communicate 1086 o No encryption is provided in order to be able to communicate 1088 o Flag dot11OCBActivated is set to true 1090 All the nodes in the radio communication range (IP-OBU and IP-RSU) 1091 receive all the messages transmitted (IP-OBU and IP-RSU) within the 1092 radio communications range. The eventual conflict(s) are resolved by 1093 the MAC CDMA function. 1095 The message exchange diagram in Figure 4 illustrates a comparison 1096 between traditional 802.11 and 802.11 in OCB mode. The 'Data' 1097 messages can be IP packets such as HTTP or others. Other 802.11 1098 management and control frames (non IP) may be transmitted, as 1099 specified in the 802.11 standard. For information, the names of 1100 these messages as currently specified by the 802.11 standard are 1101 listed in Appendix G. 1103 STA AP STA1 STA2 1104 | | | | 1105 |<------ Beacon -------| |<------ Data -------->| 1106 | | | | 1107 |---- Probe Req. ----->| |<------ Data -------->| 1108 |<--- Probe Res. ------| | | 1109 | | |<------ Data -------->| 1110 |---- Auth Req. ------>| | | 1111 |<--- Auth Res. -------| |<------ Data -------->| 1112 | | | | 1113 |---- Asso Req. ------>| |<------ Data -------->| 1114 |<--- Asso Res. -------| | | 1115 | | |<------ Data -------->| 1116 |<------ Data -------->| | | 1117 |<------ Data -------->| |<------ Data -------->| 1119 (i) 802.11 Infrastructure mode (ii) 802.11-OCB mode 1121 Figure 4: Difference between messages exchanged on 802.11 (left) and 1122 802.11-OCB (right) 1124 The interface 802.11-OCB was specified in IEEE Std 802.11p (TM) -2010 1125 [IEEE-802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, 1126 titled "Amendment 6: Wireless Access in Vehicular Environments". 1127 Since then, this amendment has been integrated in IEEE 802.11(TM) 1128 -2012 and -2016 [IEEE-802.11-2016]. 1130 In document 802.11-2016, anything qualified specifically as 1131 "OCBActivated", or "outside the context of a basic service" set to be 1132 true, then it is actually referring to OCB aspects introduced to 1133 802.11. 1135 In order to delineate the aspects introduced by 802.11-OCB to 802.11, 1136 we refer to the earlier [IEEE-802.11p-2010]. The amendment is 1137 concerned with vehicular communications, where the wireless link is 1138 similar to that of Wireless LAN (using a PHY layer specified by 1139 802.11a/b/g/n), but which needs to cope with the high mobility factor 1140 inherent in scenarios of communications between moving vehicles, and 1141 between vehicles and fixed infrastructure deployed along roads. 1142 While 'p' is a letter identifying the Ammendment, just like 'a, b, g' 1143 and 'n' are, 'p' is concerned more with MAC modifications, and a 1144 little with PHY modifications; the others are mainly about PHY 1145 modifications. It is possible in practice to combine a 'p' MAC with 1146 an 'a' PHY by operating outside the context of a BSS with OFDM at 1147 5.4GHz and 5.9GHz. 1149 The 802.11-OCB links are specified to be compatible as much as 1150 possible with the behaviour of 802.11a/b/g/n and future generation 1151 IEEE WLAN links. From the IP perspective, an 802.11-OCB MAC layer 1152 offers practically the same interface to IP as the 802.11a/b/g/n and 1153 802.3. A packet sent by an IP-OBU may be received by one or multiple 1154 IP-RSUs. The link-layer resolution is performed by using the IPv6 1155 Neighbor Discovery protocol. 1157 To support this similarity statement (IPv6 is layered on top of LLC 1158 on top of 802.11-OCB, in the same way that IPv6 is layered on top of 1159 LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on 1160 top of 802.3 (for Ethernet)) it is useful to analyze the differences 1161 between 802.11-OCB and 802.11 specifications. During this analysis, 1162 we note that whereas 802.11-OCB lists relatively complex and numerous 1163 changes to the MAC layer (and very little to the PHY layer), there 1164 are only a few characteristics which may be important for an 1165 implementation transmitting IPv6 packets on 802.11-OCB links. 1167 The most important 802.11-OCB point which influences the IPv6 1168 functioning is the OCB characteristic; an additional, less direct 1169 influence, is the maximum bandwidth afforded by the PHY modulation/ 1170 demodulation methods and channel access specified by 802.11-OCB. The 1171 maximum bandwidth theoretically possible in 802.11-OCB is 54 Mbit/s 1172 (when using, for example, the following parameters: 20 MHz channel; 1173 modulation 64-QAM; coding rate R is 3/4); in practice of IP-over- 1174 802.11-OCB a commonly observed figure is 12Mbit/s; this bandwidth 1175 allows the operation of a wide range of protocols relying on IPv6. 1177 o Operation Outside the Context of a BSS (OCB): the (earlier 1178 802.11p) 802.11-OCB links are operated without a Basic Service Set 1179 (BSS). This means that the frames IEEE 802.11 Beacon, Association 1180 Request/Response, Authentication Request/Response, and similar, 1181 are not used. The used identifier of BSS (BSSID) has a 1182 hexadecimal value always 0xffffffffffff (48 '1' bits, represented 1183 as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' 1184 BSSID), as opposed to an arbitrary BSSID value set by 1185 administrator (e.g. 'My-Home-AccessPoint'). The OCB operation - 1186 namely the lack of beacon-based scanning and lack of 1187 authentication - should be taken into account when the Mobile IPv6 1188 protocol [RFC6275] and the protocols for IP layer security 1189 [RFC4301] are used. The way these protocols adapt to OCB is not 1190 described in this document. 1192 o Timing Advertisement: is a new message defined in 802.11-OCB, 1193 which does not exist in 802.11a/b/g/n. This message is used by 1194 stations to inform other stations about the value of time. It is 1195 similar to the time as delivered by a GNSS system (Galileo, GPS, 1196 ...) or by a cellular system. This message is optional for 1197 implementation. 1199 o Frequency range: this is a characteristic of the PHY layer, with 1200 almost no impact on the interface between MAC and IP. However, it 1201 is worth considering that the frequency range is regulated by a 1202 regional authority (ARCEP, ECC/CEPT based on ENs from ETSI, FCC, 1203 etc.); as part of the regulation process, specific applications 1204 are associated with specific frequency ranges. In the case of 1205 802.11-OCB, the regulator associates a set of frequency ranges, or 1206 slots within a band, to the use of applications of vehicular 1207 communications, in a band known as "5.9GHz". The 5.9GHz band is 1208 different from the 2.4GHz and 5GHz bands used by Wireless LAN. 1209 However, as with Wireless LAN, the operation of 802.11-OCB in 1210 "5.9GHz" bands is exempt from owning a license in EU (in US the 1211 5.9GHz is a licensed band of spectrum; for the fixed 1212 infrastructure an explicit FCC authorization is required; for an 1213 on-board device a 'licensed-by-rule' concept applies: rule 1214 certification conformity is required.) Technical conditions are 1215 different than those of the bands "2.4GHz" or "5GHz". The allowed 1216 power levels, and implicitly the maximum allowed distance between 1217 vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20 1218 dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum 1219 distance of approximately 1km, compared to approximately 50m. 1220 Additionally, specific conditions related to congestion avoidance, 1221 jamming avoidance, and radar detection are imposed on the use of 1222 DSRC (in US) and on the use of frequencies for Intelligent 1223 Transportation Systems (in EU), compared to Wireless LAN 1224 (802.11a/b/g/n). 1226 o 'Half-rate' encoding: as the frequency range, this parameter is 1227 related to PHY, and thus has not much impact on the interface 1228 between the IP layer and the MAC layer. 1230 o In vehicular communications using 802.11-OCB links, there are 1231 strong privacy requirements with respect to addressing. While the 1232 802.11-OCB standard does not specify anything in particular with 1233 respect to MAC addresses, in these settings there exists a strong 1234 need for dynamic change of these addresses (as opposed to the non- 1235 vehicular settings - real wall protection - where fixed MAC 1236 addresses do not currently pose some privacy risks). This is 1237 further described in Section 5. A relevant function is described 1238 in IEEE 1609.3-2016 [IEEE-1609.3], clause 5.5.1 and IEEE 1239 1609.4-2016 [IEEE-1609.4], clause 6.7. 1241 Other aspects particular to 802.11-OCB, which are also particular to 1242 802.11 (e.g. the 'hidden node' operation), may have an influence on 1243 the use of transmission of IPv6 packets on 802.11-OCB networks. The 1244 OCB subnet structure is described in Section 4.6. 1246 Appendix D. Changes Needed on a software driver 802.11a to become a 1247 802.11-OCB driver 1249 The 802.11p amendment modifies both the 802.11 stack's physical and 1250 MAC layers but all the induced modifications can be quite easily 1251 obtained by modifying an existing 802.11a ad-hoc stack. 1253 Conditions for a 802.11a hardware to be 802.11-OCB compliant: 1255 o The PHY entity shall be an orthogonal frequency division 1256 multiplexing (OFDM) system. It must support the frequency bands 1257 on which the regulator recommends the use of ITS communications, 1258 for example using IEEE 802.11-OCB layer, in France: 5875MHz to 1259 5925MHz. 1261 o The OFDM system must provide a "half-clocked" operation using 10 1262 MHz channel spacings. 1264 o The chip transmit spectrum mask must be compliant to the "Transmit 1265 spectrum mask" from the IEEE 802.11p amendment (but experimental 1266 environments tolerate otherwise). 1268 o The chip should be able to transmit up to 44.8 dBm when used by 1269 the US government in the United States, and up to 33 dBm in 1270 Europe; other regional conditions apply. 1272 Changes needed on the network stack in OCB mode: 1274 o Physical layer: 1276 * The chip must use the Orthogonal Frequency Multiple Access 1277 (OFDM) encoding mode. 1279 * The chip must be set in half-mode rate mode (the internal clock 1280 frequency is divided by two). 1282 * The chip must use dedicated channels and should allow the use 1283 of higher emission powers. This may require modifications to 1284 the local computer file that describes regulatory domains 1285 rules, if used by the kernel to enforce local specific 1286 restrictions. Such modifications to the local computer file 1287 must respect the location-specific regulatory rules. 1289 MAC layer: 1291 * All management frames (beacons, join, leave, and others) 1292 emission and reception must be disabled except for frames of 1293 subtype Action and Timing Advertisement (defined below). 1295 * No encryption key or method must be used. 1297 * Packet emission and reception must be performed as in ad-hoc 1298 mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff). 1300 * The functions related to joining a BSS (Association Request/ 1301 Response) and for authentication (Authentication Request/Reply, 1302 Challenge) are not called. 1304 * The beacon interval is always set to 0 (zero). 1306 * Timing Advertisement frames, defined in the amendment, should 1307 be supported. The upper layer should be able to trigger such 1308 frames emission and to retrieve information contained in 1309 received Timing Advertisements. 1311 Appendix E. EtherType Protocol Discrimination (EPD) 1313 A more theoretical and detailed view of layer stacking, and 1314 interfaces between the IP layer and 802.11-OCB layers, is illustrated 1315 in Figure 5. The IP layer operates on top of the EtherType Protocol 1316 Discrimination (EPD); this Discrimination layer is described in IEEE 1317 Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP 1318 (Link Layer Control Service Access Point). 1320 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1321 | IPv6 | 1322 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ 1323 { LLC_SAP } 802.11-OCB 1324 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary 1325 | EPD | | | 1326 | | MLME | | 1327 +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | 1328 | MAC Sublayer | | | 802.11-OCB 1329 | and ch. coord. | | SME | Services 1330 +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | 1331 | | PLME | | 1332 | PHY Layer | PLME_SAP | 1333 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1335 Figure 5: EtherType Protocol Discrimination 1337 Appendix F. Design Considerations 1339 The networks defined by 802.11-OCB are in many ways similar to other 1340 networks of the 802.11 family. In theory, the encapsulation of IPv6 1341 over 802.11-OCB could be very similar to the operation of IPv6 over 1342 other networks of the 802.11 family. However, the high mobility, 1343 strong link asymmetry and very short connection makes the 802.11-OCB 1344 link significantly different from other 802.11 networks. Also, the 1345 automotive applications have specific requirements for reliability, 1346 security and privacy, which further add to the particularity of the 1347 802.11-OCB link. 1349 F.1. Vehicle ID 1351 In automotive networks it is required that each node is represented 1352 uniquely at a certain point in time. Accordingly, a vehicle must be 1353 identified by at least one unique identifier. The current 1354 specification at ETSI and at IEEE 1609 identifies a vehicle by its 1355 MAC address, which is obtained from the 802.11-OCB Network Interface 1356 Card (NIC). 1358 In case multiple 802.11-OCB NICs are present in one car, implicitely 1359 multiple vehicle IDs will be generated. Additionally, some software 1360 generates a random MAC address each time the computer boots; this 1361 constitutes an additional difficulty. 1363 A mechanim to uniquely identify a vehicle irrespectively to the 1364 multiplicity of NICs, or frequent MAC address generation, is 1365 necessary. 1367 F.2. Reliability Requirements 1369 The dynamically changing topology, short connectivity, mobile 1370 transmitter and receivers, different antenna heights, and many-to- 1371 many communication types, make IEEE 802.11-OCB links significantly 1372 different from other IEEE 802.11 links. Any IPv6 mechanism operating 1373 on IEEE 802.11-OCB link must support strong link asymmetry, spatio- 1374 temporal link quality, fast address resolution and transmission. 1376 IEEE 802.11-OCB strongly differs from other 802.11 systems to operate 1377 outside of the context of a Basic Service Set. This means in 1378 practice that IEEE 802.11-OCB does not rely on a Base Station for all 1379 Basic Service Set management. In particular, IEEE 802.11-OCB shall 1380 not use beacons. Any IPv6 mechanism requiring L2 services from IEEE 1381 802.11 beacons must support an alternative service. 1383 Channel scanning being disabled, IPv6 over IEEE 802.11-OCB must 1384 implement a mechanism for transmitter and receiver to converge to a 1385 common channel. 1387 Authentication not being possible, IPv6 over IEEE 802.11-OCB must 1388 implement an distributed mechanism to authenticate transmitters and 1389 receivers without the support of a DHCP server. 1391 Time synchronization not being available, IPv6 over IEEE 802.11-OCB 1392 must implement a higher layer mechanism for time synchronization 1393 between transmitters and receivers without the support of a NTP 1394 server. 1396 The IEEE 802.11-OCB link being asymmetric, IPv6 over IEEE 802.11-OCB 1397 must disable management mechanisms requesting acknowledgements or 1398 replies. 1400 The IEEE 802.11-OCB link having a short duration time, IPv6 over IEEE 1401 802.11-OCB should implement fast IPv6 mobility management mechanisms. 1403 F.3. Multiple interfaces 1405 There are considerations for 2 or more IEEE 802.11-OCB interface 1406 cards per vehicle. For each vehicle taking part in road traffic, one 1407 IEEE 802.11-OCB interface card could be fully allocated for Non IP 1408 safety-critical communication. Any other IEEE 802.11-OCB may be used 1409 for other type of traffic. 1411 The mode of operation of these other wireless interfaces is not 1412 clearly defined yet. One possibility is to consider each card as an 1413 independent network interface, with a specific MAC Address and a set 1414 of IPv6 addresses. Another possibility is to consider the set of 1415 these wireless interfaces as a single network interface (not 1416 including the IEEE 802.11-OCB interface used by Non IP safety 1417 critical communications). This will require specific logic to 1418 ensure, for example, that packets meant for a vehicle in front are 1419 actually sent by the radio in the front, or that multiple copies of 1420 the same packet received by multiple interfaces are treated as a 1421 single packet. Treating each wireless interface as a separate 1422 network interface pushes such issues to the application layer. 1424 Certain privacy requirements imply that if these multiple interfaces 1425 are represented by many network interface, a single renumbering event 1426 shall cause renumbering of all these interfaces. If one MAC changed 1427 and another stayed constant, external observers would be able to 1428 correlate old and new values, and the privacy benefits of 1429 randomization would be lost. 1431 The privacy requirements of Non IP safety-critical communications 1432 imply that if a change of pseudonyme occurs, renumbering of all other 1433 interfaces shall also occur. 1435 F.4. MAC Address Generation 1437 In 802.11-OCB networks, the MAC addresses may change during well 1438 defined renumbering events. A 'randomized' MAC address has the 1439 following characteristics: 1441 o Bit "Local/Global" set to "locally admninistered". 1443 o Bit "Unicast/Multicast" set to "Unicast". 1445 o The 46 remaining bits are set to a random value, using a random 1446 number generator that meets the requirements of [RFC4086]. 1448 To meet the randomization requirements for the 46 remaining bits, a 1449 hash function may be used. For example, the SHA256 hash function may 1450 be used with input a 256 bit local secret, the "nominal" MAC Address 1451 of the interface, and a representation of the date and time of the 1452 renumbering event. 1454 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode 1456 For information, at the time of writing, this is the list of IEEE 1457 802.11 messages that may be transmitted in OCB mode, i.e. when 1458 dot11OCBActivated is true in a STA: 1460 o The STA may send management frames of subtype Action and, if the 1461 STA maintains a TSF Timer, subtype Timing Advertisement; 1463 o The STA may send control frames, except those of subtype PS-Poll, 1464 CF-End, and CF-End plus CFAck; 1466 o The STA may send data frames of subtype Data, Null, QoS Data, and 1467 QoS Null. 1469 Appendix H. Implementation Status 1471 This section describes an example of an IPv6 Packet captured over a 1472 IEEE 802.11-OCB link. 1474 By way of example we show that there is no modification in the 1475 headers when transmitted over 802.11-OCB networks - they are 1476 transmitted like any other 802.11 and Ethernet packets. 1478 We describe an experiment of capturing an IPv6 packet on an 1479 802.11-OCB link. In topology depicted in Figure 6, the packet is an 1480 IPv6 Router Advertisement. This packet is emitted by a Router on its 1481 802.11-OCB interface. The packet is captured on the Host, using a 1482 network protocol analyzer (e.g. Wireshark); the capture is performed 1483 in two different modes: direct mode and 'monitor' mode. The topology 1484 used during the capture is depicted below. 1486 The packet is captured on the Host. The Host is an IP-OBU containing 1487 an 802.11 interface in format PCI express (an ITRI product). The 1488 kernel runs the ath5k software driver with modifications for OCB 1489 mode. The capture tool is Wireshark. The file format for save and 1490 analyze is 'pcap'. The packet is generated by the Router. The 1491 Router is an IP-RSU (ITRI product). 1493 +--------+ +-------+ 1494 | | 802.11-OCB Link | | 1495 ---| Router |--------------------------------| Host | 1496 | | | | 1497 +--------+ +-------+ 1499 Figure 6: Topology for capturing IP packets on 802.11-OCB 1501 During several capture operations running from a few moments to 1502 several hours, no message relevant to the BSSID contexts were 1503 captured (no Association Request/Response, Authentication Req/Resp, 1504 Beacon). This shows that the operation of 802.11-OCB is outside the 1505 context of a BSSID. 1507 Overall, the captured message is identical with a capture of an IPv6 1508 packet emitted on a 802.11b interface. The contents are precisely 1509 similar. 1511 H.1. Capture in Monitor Mode 1513 The IPv6 RA packet captured in monitor mode is illustrated below. 1514 The radio tap header provides more flexibility for reporting the 1515 characteristics of frames. The Radiotap Header is prepended by this 1516 particular stack and operating system on the Host machine to the RA 1517 packet received from the network (the Radiotap Header is not present 1518 on the air). The implementation-dependent Radiotap Header is useful 1519 for piggybacking PHY information from the chip's registers as data in 1520 a packet understandable by userland applications using Socket 1521 interfaces (the PHY interface can be, for example: power levels, data 1522 rate, ratio of signal to noise). 1524 The packet present on the air is formed by IEEE 802.11 Data Header, 1525 Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. 1527 Radiotap Header v0 1528 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1529 |Header Revision| Header Pad | Header length | 1530 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1531 | Present flags | 1532 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1533 | Data Rate | Pad | 1534 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1536 IEEE 802.11 Data Header 1537 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1538 | Type/Subtype and Frame Ctrl | Duration | 1539 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1540 | Receiver Address... 1541 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1542 ... Receiver Address | Transmitter Address... 1543 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1544 ... Transmitter Address | 1545 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1546 | BSS Id... 1547 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1548 ... BSS Id | Frag Number and Seq Number | 1549 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1551 Logical-Link Control Header 1552 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1553 | DSAP |I| SSAP |C| Control field | Org. code... 1554 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1555 ... Organizational Code | Type | 1556 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1558 IPv6 Base Header 1559 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1560 |Version| Traffic Class | Flow Label | 1561 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1562 | Payload Length | Next Header | Hop Limit | 1563 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1564 | | 1565 + + 1566 | | 1567 + Source Address + 1568 | | 1569 + + 1570 | | 1571 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1572 | | 1573 + + 1574 | | 1575 + Destination Address + 1576 | | 1577 + + 1578 | | 1579 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1581 Router Advertisement 1582 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1583 | Type | Code | Checksum | 1584 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1585 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1586 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1587 | Reachable Time | 1588 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1589 | Retrans Timer | 1590 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1591 | Options ... 1592 +-+-+-+-+-+-+-+-+-+-+-+- 1594 The value of the Data Rate field in the Radiotap header is set to 6 1595 Mb/s. This indicates the rate at which this RA was received. 1597 The value of the Transmitter address in the IEEE 802.11 Data Header 1598 is set to a 48bit value. The value of the destination address is 1599 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS 1600 Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network 1601 protocol analyzer as being "broadcast". The Fragment number and 1602 sequence number fields are together set to 0x90C6. 1604 The value of the Organization Code field in the Logical-Link Control 1605 Header is set to 0x0, recognized as "Encapsulated Ethernet". The 1606 value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise 1607 #86DD), recognized as "IPv6". 1609 A Router Advertisement is periodically sent by the router to 1610 multicast group address ff02::1. It is an icmp packet type 134. The 1611 IPv6 Neighbor Discovery's Router Advertisement message contains an 1612 8-bit field reserved for single-bit flags, as described in [RFC4861]. 1614 The IPv6 header contains the link local address of the router 1615 (source) configured via EUI-64 algorithm, and destination address set 1616 to ff02::1. Recent versions of network protocol analyzers (e.g. 1617 Wireshark) provide additional informations for an IP address, if a 1618 geolocalization database is present. In this example, the 1619 geolocalization database is absent, and the "GeoIP" information is 1620 set to unknown for both source and destination addresses (although 1621 the IPv6 source and destination addresses are set to useful values). 1622 This "GeoIP" can be a useful information to look up the city, 1623 country, AS number, and other information for an IP address. 1625 The Ethernet Type field in the logical-link control header is set to 1626 0x86dd which indicates that the frame transports an IPv6 packet. In 1627 the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 1628 which is the corresponding multicast MAC address. The BSS id is a 1629 broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link 1630 duration between vehicles and the roadside infrastructure, there is 1631 no need in IEEE 802.11-OCB to wait for the completion of association 1632 and authentication procedures before exchanging data. IEEE 1633 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) 1634 and may start communicating as soon as they arrive on the 1635 communication channel. 1637 H.2. Capture in Normal Mode 1639 The same IPv6 Router Advertisement packet described above (monitor 1640 mode) is captured on the Host, in the Normal mode, and depicted 1641 below. 1643 Ethernet II Header 1644 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1645 | Destination... 1646 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1647 ...Destination | Source... 1648 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1649 ...Source | 1650 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1651 | Type | 1652 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1654 IPv6 Base Header 1655 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1656 |Version| Traffic Class | Flow Label | 1657 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1658 | Payload Length | Next Header | Hop Limit | 1659 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1660 | | 1661 + + 1662 | | 1663 + Source Address + 1664 | | 1665 + + 1666 | | 1667 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1668 | | 1669 + + 1670 | | 1671 + Destination Address + 1672 | | 1673 + + 1674 | | 1675 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1677 Router Advertisement 1678 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1679 | Type | Code | Checksum | 1680 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1681 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1682 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1683 | Reachable Time | 1684 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1685 | Retrans Timer | 1686 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1687 | Options ... 1688 +-+-+-+-+-+-+-+-+-+-+-+- 1690 One notices that the Radiotap Header, the IEEE 802.11 Data Header and 1691 the Logical-Link Control Headers are not present. On the other hand, 1692 a new header named Ethernet II Header is present. 1694 The Destination and Source addresses in the Ethernet II header 1695 contain the same values as the fields Receiver Address and 1696 Transmitter Address present in the IEEE 802.11 Data Header in the 1697 "monitor" mode capture. 1699 The value of the Type field in the Ethernet II header is 0x86DD 1700 (recognized as "IPv6"); this value is the same value as the value of 1701 the field Type in the Logical-Link Control Header in the "monitor" 1702 mode capture. 1704 The knowledgeable experimenter will no doubt notice the similarity of 1705 this Ethernet II Header with a capture in normal mode on a pure 1706 Ethernet cable interface. 1708 An Adaptation layer is inserted on top of a pure IEEE 802.11 MAC 1709 layer, in order to adapt packets, before delivering the payload data 1710 to the applications. It adapts 802.11 LLC/MAC headers to Ethernet II 1711 headers. In further detail, this adaptation consists in the 1712 elimination of the Radiotap, 802.11 and LLC headers, and in the 1713 insertion of the Ethernet II header. In this way, IPv6 runs straight 1714 over LLC over the 802.11-OCB MAC layer; this is further confirmed by 1715 the use of the unique Type 0x86DD. 1717 Appendix I. Extra Terminology 1719 The following terms are defined outside the IETF. They are used to 1720 define the main terms in the main terminology section Section 2. 1722 DSRC (Dedicated Short Range Communication): a term defined outside 1723 the IETF. The US Federal Communications Commission (FCC) Dedicated 1724 Short Range Communication (DSRC) is defined in the Code of Federal 1725 Regulations (CFR) 47, Parts 90 and 95. This Code is referred in the 1726 definitions below. At the time of the writing of this Internet 1727 Draft, the last update of this Code was dated October 1st, 2010. 1729 DSRCS (Dedicated Short-Range Communications Services): a term defined 1730 outside the IETF. The use of radio techniques to transfer data over 1731 short distances between roadside and mobile units, between mobile 1732 units, and between portable and mobile units to perform operations 1733 related to the improvement of traffic flow, traffic safety, and other 1734 intelligent transportation service applications in a variety of 1735 environments. DSRCS systems may also transmit status and 1736 instructional messages related to the units involve. [Ref. 47 CFR 1737 90.7 - Definitions] 1738 OBU (On-Board Unit): a term defined outside the IETF. An On-Board 1739 Unit is a DSRCS transceiver that is normally mounted in or on a 1740 vehicle, or which in some instances may be a portable unit. An OBU 1741 can be operational while a vehicle or person is either mobile or 1742 stationary. The OBUs receive and contend for time to transmit on one 1743 or more radio frequency (RF) channels. Except where specifically 1744 excluded, OBU operation is permitted wherever vehicle operation or 1745 human passage is permitted. The OBUs mounted in vehicles are 1746 licensed by rule under part 95 of the respective chapter and 1747 communicate with Roadside Units (RSUs) and other OBUs. Portable OBUs 1748 are also licensed by rule under part 95 of the respective chapter. 1749 OBU operations in the Unlicensed National Information Infrastructure 1750 (UNII) Bands follow the rules in those bands. - [CFR 90.7 - 1751 Definitions]. 1753 RSU (Road-Side Unit): a term defined outside of IETF. A Roadside 1754 Unit is a DSRC transceiver that is mounted along a road or pedestrian 1755 passageway. An RSU may also be mounted on a vehicle or is hand 1756 carried, but it may only operate when the vehicle or hand- carried 1757 unit is stationary. Furthermore, an RSU operating under the 1758 respectgive part is restricted to the location where it is licensed 1759 to operate. However, portable or hand-held RSUs are permitted to 1760 operate where they do not interfere with a site-licensed operation. 1761 A RSU broadcasts data to OBUs or exchanges data with OBUs in its 1762 communications zone. An RSU also provides channel assignments and 1763 operating instructions to OBUs in its communications zone, when 1764 required. - [CFR 90.7 - Definitions]. 1766 Authors' Addresses 1768 Alexandre Petrescu 1769 CEA, LIST 1770 CEA Saclay 1771 Gif-sur-Yvette , Ile-de-France 91190 1772 France 1774 Phone: +33169089223 1775 Email: Alexandre.Petrescu@cea.fr 1777 Nabil Benamar 1778 Moulay Ismail University 1779 Morocco 1781 Phone: +212670832236 1782 Email: n.benamar@est.umi.ac.ma 1783 Jerome Haerri 1784 Eurecom 1785 Sophia-Antipolis 06904 1786 France 1788 Phone: +33493008134 1789 Email: Jerome.Haerri@eurecom.fr 1791 Jong-Hyouk Lee 1792 Sangmyung University 1793 31, Sangmyeongdae-gil, Dongnam-gu 1794 Cheonan 31066 1795 Republic of Korea 1797 Email: jonghyouk@smu.ac.kr 1799 Thierry Ernst 1800 YoGoKo 1801 France 1803 Email: thierry.ernst@yogoko.fr