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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 17, 2018 Moulay Ismail University 6 J. Haerri 7 Eurecom 8 J. Lee 9 Sangmyung University 10 T. Ernst 11 YoGoKo 12 February 13, 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-15.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 17, 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 . . . . . . . . . . . . . . . . . . . . . . 22 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 . . . . . . . . . . . . . . . . 29 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 . . . . . . . . . . . . . . . 31 98 H.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . 32 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 WiFi: Wireless Fidelity. 143 IP-OBU (Internet Protocol On-Board Unit): an IP-OBU is a computer 144 situated in a vehicle such as an automobile, bicycle, or similar. It 145 has at least one IP interface that runs in mode OCB of 802.11, and 146 that has an "OBU" transceiver. See the definition of the term "OBU" 147 in section Appendix I. 149 IP-RSU (IP Road-Side Unit): an IP-RSU is situated along the road. An 150 IP-RSU has at least two distinct IP-enabled interfaces; at least one 151 interface is operated in mode OCB of IEEE 802.11 and is IP-enabled. 152 An IP-RSU is similar to a Wireless Termination Point (WTP), as 153 defined in [RFC5415], or an Access Point (AP), as defined in IEEE 154 documents, or an Access Network Router (ANR) defined in [RFC3753], 155 with one key particularity: the wireless PHY/MAC layer of at least 156 one of its IP-enabled interfaces is configured to operate in 157 802.11-OCB mode. The IP-RSU communicates with the IP-OBU in the 158 vehicle over 802.11 wireless link operating in OCB mode. 160 OCB (outside the context of a basic service set - BSS): A mode of 161 operation in which a STA is not a member of a BSS and does not 162 utilize IEEE Std 802.11 authentication, association, or data 163 confidentiality. 165 802.11-OCB: mode specified in IEEE Std 802.11-2016 when the MIB 166 attribute dot11OCBActivited is true. The OCB mode requires 167 transmission of QoS data frames (IEEE Std 802.11e), half-clocked 168 operation (IEEE Std 802.11j), and use of 5.9 GHz frequency band. 169 Nota: any implementation should comply with standards and regulations 170 set in the different countries for using that frequency band. 172 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 174 The IEEE 802.11-OCB Networks are used for vehicular communications, 175 as 'Wireless Access in Vehicular Environments'. The IP communication 176 scenarios for these environments have been described in several 177 documents; in particular, we refer the reader to 178 [I-D.ietf-ipwave-vehicular-networking-survey], that lists some 179 scenarios and requirements for IP in Intelligent Transportation 180 Systems. 182 The link model is the following: STA --- 802.11-OCB --- STA. In 183 vehicular networks, STAs can be IP-RSUs and/or IP-OBUs. While 184 802.11-OCB is clearly specified, and the use of IPv6 over such link 185 is not radically new, the operating environment (vehicular networks) 186 brings in new perspectives. 188 The mechanisms for forming and terminating, discovering, peering and 189 mobility management for 802.11-OCB links are not described in this 190 document. 192 4. IPv6 over 802.11-OCB 194 4.1. Maximum Transmission Unit (MTU) 196 The default MTU for IP packets on 802.11-OCB MUST be 1500 octets. It 197 is the same value as IPv6 packets on Ethernet links, as specified in 198 [RFC2464]. This value of the MTU respects the recommendation that 199 every link on the Internet must have a minimum MTU of 1280 octets 200 (stated in [RFC8200], and the recommendations therein, especially 201 with respect to fragmentation). If IPv6 packets of size larger than 202 1500 bytes are sent on an 802.11-OCB interface card then the IP stack 203 will fragment. In case there are IP fragments, the field "Sequence 204 number" of the 802.11 Data header containing the IP fragment field is 205 increased. 207 Non-IP packets such as WAVE Short Message Protocol (WSMP) can be 208 delivered on 802.11-OCB links. Specifications of these packets are 209 out of scope of this document, and do not impose any limit on the MTU 210 size, allowing an arbitrary number of 'containers'. Non-IP packets 211 such as ETSI GeoNetworking packets have an MTU of 1492 bytes. The 212 operation of IPv6 over GeoNetworking is specified at 213 [ETSI-IPv6-GeoNetworking]. 215 4.2. Frame Format 217 IP packets are transmitted over 802.11-OCB as standard Ethernet 218 packets. As with all 802.11 frames, an Ethernet adaptation layer is 219 used with 802.11-OCB as well. This Ethernet Adaptation Layer 220 performing 802.11-to-Ethernet is described in Section 4.2.1. The 221 Ethernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal 86DD, 222 or otherwise #86DD). 224 The Frame format for transmitting IPv6 on 802.11-OCB networks is the 225 same as transmitting IPv6 on Ethernet networks, and is described in 226 section 3 of [RFC2464]. 228 1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1 229 is the binary representation of the EtherType value 0x86DD. 231 4.2.1. Ethernet Adaptation Layer 233 An 'adaptation' layer is inserted between a MAC layer and the 234 Networking layer. This is used to transform some parameters between 235 their form expected by the IP stack and the form provided by the MAC 236 layer. 238 An Ethernet Adaptation Layer makes an 802.11 MAC look to IP 239 Networking layer as a more traditional Ethernet layer. At reception, 240 this layer takes as input the IEEE 802.11 Data Header and the 241 Logical-Link Layer Control Header and produces an Ethernet II Header. 242 At sending, the reverse operation is performed. 244 The operation of the Ethernet Adaptation Layer is depicted by the 245 double arrow in Figure 1. 247 +--------------------+------------+-------------+---------+-----------+ 248 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer| 249 +--------------------+------------+-------------+---------+-----------+ 250 \ / \ / 251 ----------------------------- -------- 252 \---------------------------------------------/ 253 ^ 254 | 255 802.11-to-Ethernet Adaptation Layer 256 | 257 v 258 +---------------------+-------------+---------+ 259 | Ethernet II Header | IPv6 Header | Payload | 260 +---------------------+-------------+---------+ 262 Figure 1: Operation of the Ethernet Adaptation Layer 264 The Receiver and Transmitter Address fields in the 802.11 Data Header 265 MUST contain the same values as the Destination and the Source 266 Address fields in the Ethernet II Header, respectively. The value of 267 the Type field in the LLC Header MUST be the same as the value of the 268 Type field in the Ethernet II Header. 270 The ".11 Trailer" contains solely a 4-byte Frame Check Sequence. 272 Additionally, the Ethernet Adaptation Layer performs operations in 273 relation to IP fragmentation and MTU. One of these operations is 274 briefly described in Section 4.1. 276 In OCB mode, IPv6 packets MAY be transmitted either as "IEEE 802.11 277 Data" or alternatively as "IEEE 802.11 QoS Data", as illustrated in 278 Figure 2. 280 +--------------------+-------------+-------------+---------+-----------+ 281 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer| 282 +--------------------+-------------+-------------+---------+-----------+ 284 or 286 +--------------------+-------------+-------------+---------+-----------+ 287 | 802.11 QoS Data Hdr| LLC Header | IPv6 Header | Payload |.11 Trailer| 288 +--------------------+-------------+-------------+---------+-----------+ 290 Figure 2: 802.11 Data Header or 802.11 QoS Data Header 292 The distinction between the two formats is given by the value of the 293 field "Type/Subtype". The value of the field "Type/Subtype" in the 294 802.11 Data header is 0x0020. The value of the field "Type/Subtype" 295 in the 802.11 QoS header is 0x0028. 297 The mapping between qos-related fields in the IPv6 header (e.g. 298 "Traffic Class", "Flow label") and fields in the "802.11 QoS Data 299 Header" (e.g. "QoS Control") are not specified in this document. 300 Guidance for a potential mapping is provided in 301 [I-D.ietf-tsvwg-ieee-802-11], although it is not specific to OCB 302 mode. 304 The placement of IPv6 networking layer on Ethernet Adaptation Layer 305 is illustrated in Figure 3. 307 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 308 | IPv6 | 309 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 310 | Ethernet Adaptation Layer | 311 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 312 | 802.11 WiFi MAC | 313 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 314 | 802.11 WiFi PHY | 315 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 317 Figure 3: Ethernet Adaptation Layer stacked with other layers 319 (in the above figure, a WiFi profile is represented; this is used 320 also for OCB profile.) 322 Other alternative views of layering are EtherType Protocol 323 Discrimination (EPD), see Appendix E, and SNAP see [RFC1042]. 325 4.3. Link-Local Addresses 327 The link-local address of an 802.11-OCB interface is formed in the 328 same manner as on an Ethernet interface. This manner is described in 329 section 5 of [RFC2464]. Additionally, if stable identifiers are 330 needed, it is recommended to follow the Recommendation on Stable IPv6 331 Interface Identifiers [RFC8064]. Additionally, if semantically 332 opaque Interface Identifiers are needed, a potential method for 333 generating semantically opaque Interface Identifiers with IPv6 334 Stateless Address Autoconfiguration is given in [RFC7217]. 336 4.4. Address Mapping 338 For unicast as for multicast, there is no change from the unicast and 339 multicast address mapping format of Ethernet interfaces, as defined 340 by sections 6 and 7 of [RFC2464]. 342 4.4.1. Address Mapping -- Unicast 344 The procedure for mapping IPv6 unicast addresses into Ethernet link- 345 layer addresses is described in [RFC4861]. 347 4.4.2. Address Mapping -- Multicast 349 The multicast address mapping is performed according to the method 350 specified in section 7 of [RFC2464]. The meaning of the value "3333" 351 mentioned in that section 7 of [RFC2464] is defined in section 2.3.1 352 of [RFC7042]. 354 Transmitting IPv6 packets to multicast destinations over 802.11 links 355 proved to have some performance issues 356 [I-D.perkins-intarea-multicast-ieee802]. These issues may be 357 exacerbated in OCB mode. Solutions for these problems should 358 consider the OCB mode of operation. 360 4.5. Stateless Autoconfiguration 362 The Interface Identifier for an 802.11-OCB interface is formed using 363 the same rules as the Interface Identifier for an Ethernet interface; 364 this is described in section 4 of [RFC2464]. No changes are needed, 365 but some care must be taken when considering the use of the Stateless 366 Address Auto-Configuration procedure. 368 The bits in the interface identifier have no generic meaning and the 369 identifier should be treated as an opaque value. The bits 370 'Universal' and 'Group' in the identifier of an 802.11-OCB interface 371 are significant, as this is an IEEE link-layer address. The details 372 of this significance are described in [RFC7136]. 374 As with all Ethernet and 802.11 interface identifiers ([RFC7721]), 375 the identifier of an 802.11-OCB interface may involve privacy, MAC 376 address spoofing and IP address hijacking risks. A vehicle embarking 377 an OBU or an IP-OBU whose egress interface is 802.11-OCB may expose 378 itself to eavesdropping and subsequent correlation of data; this may 379 reveal data considered private by the vehicle owner; there is a risk 380 of being tracked; see the privacy considerations described in 381 Appendix F. 383 If stable Interface Identifiers are needed in order to form IPv6 384 addresses on 802.11-OCB links, it is recommended to follow the 385 recommendation in [RFC8064]. Additionally, if semantically opaque 386 Interface Identifiers are needed, a potential method for generating 387 semantically opaque Interface Identifiers with IPv6 Stateless Address 388 Autoconfiguration is given in [RFC7217]. 390 4.6. Subnet Structure 392 A subnet is formed by the external 802.11-OCB interfaces of vehicles 393 that are in close range (not their on-board interfaces). This 394 ephemeral subnet structure is strongly influenced by the mobility of 395 vehicles: the 802.11 hidden node effects appear. On another hand, 396 the structure of the internal subnets in each car is relatively 397 stable. 399 The 802.11 networks in OCB mode may be considered as 'ad-hoc' 400 networks. The addressing model for such networks is described in 401 [RFC5889]. 403 An addressing model involves several types of addresses, like 404 Globally-unique Addresses (GUA), Link-Local Addresses (LL) and Unique 405 Local Addresses (ULA). The subnet structure in 'ad-hoc' networks may 406 have characteristics that lead to difficulty of using GUAs derived 407 from a received prefix, but the LL addresses may be easier to use 408 since the prefix is constant. 410 The operation of the Neighbor Discovery protocol (ND) over 802.11 OCB 411 links is different than over 802.11 links. In OCB, the link layer 412 does not ensure that all associated members receive all messages, 413 because there is no association operation. The operation of ND over 414 802.11 OCB is not specified in this document. 416 The operation of the Mobile IPv6 protocol over 802.11 OCB links is 417 different than on other links. The Movement Detection operation 418 (section 11.5.1 of [RFC6275]) can not rely on Neighbor Unreachability 419 Detection operation of the Neighbor Discovery protocol, for the 420 reason mentioned in the previous paragraph. Also, the 802.11 OCB 421 link layer is not a lower layer that can provide an indication that a 422 link layer handover has occured. The operation of the Mobile IPv6 423 protocol over 802.11 OCB is not specified in this document. 425 5. Security Considerations 427 Any security mechanism at the IP layer or above that may be carried 428 out for the general case of IPv6 may also be carried out for IPv6 429 operating over 802.11-OCB. 431 The OCB operation is stripped off of all existing 802.11 link-layer 432 security mechanisms. There is no encryption applied below the 433 network layer running on 802.11-OCB. At application layer, the IEEE 434 1609.2 document [IEEE-1609.2] does provide security services for 435 certain applications to use; application-layer mechanisms are out-of- 436 scope of this document. On another hand, a security mechanism 437 provided at networking layer, such as IPsec [RFC4301], may provide 438 data security protection to a wider range of applications. 440 802.11-OCB does not provide any cryptographic protection, because it 441 operates outside the context of a BSS (no Association Request/ 442 Response, no Challenge messages). Any attacker can therefore just 443 sit in the near range of vehicles, sniff the network (just set the 444 interface card's frequency to the proper range) and perform attacks 445 without needing to physically break any wall. Such a link is less 446 protected than commonly used links (wired link or protected 802.11). 448 The potential attack vectors are: MAC address spoofing, IP address 449 and session hijacking and privacy violation. 451 Within the IPsec Security Architecture [RFC4301], the IPsec AH and 452 ESP headers [RFC4302] and [RFC4303] respectively, its multicast 453 extensions [RFC5374], HTTPS [RFC2818] and SeND [RFC3971] protocols 454 can be used to protect communications. Further, the assistance of 455 proper Public Key Infrastructure (PKI) protocols [RFC4210] is 456 necessary to establish credentials. More IETF protocols are 457 available in the toolbox of the IP security protocol designer. 458 Certain ETSI protocols related to security protocols in Intelligent 459 Transportation Systems are described in [ETSI-sec-archi]. 461 As with all Ethernet and 802.11 interface identifiers, there may 462 exist privacy risks in the use of 802.11-OCB interface identifiers. 463 Moreover, in outdoors vehicular settings, the privacy risks are more 464 important than in indoors settings. New risks are induced by the 465 possibility of attacker sniffers deployed along routes which listen 466 for IP packets of vehicles passing by. For this reason, in the 467 802.11-OCB deployments, there is a strong necessity to use protection 468 tools such as dynamically changing MAC addresses. This may help 469 mitigate privacy risks to a certain level. On another hand, it may 470 have an impact in the way typical IPv6 address auto-configuration is 471 performed for vehicles (SLAAC would rely on MAC addresses and would 472 hence dynamically change the affected IP address), in the way the 473 IPv6 Privacy addresses were used, and other effects. 475 6. IANA Considerations 477 No request to IANA. 479 7. Contributors 481 Christian Huitema, Tony Li. 483 Romain Kuntz contributed extensively about IPv6 handovers between 484 links running outside the context of a BSS (802.11-OCB links). 486 Tim Leinmueller contributed the idea of the use of IPv6 over 487 802.11-OCB for distribution of certificates. 489 Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey 490 Voronov provided significant feedback on the experience of using IP 491 messages over 802.11-OCB in initial trials. 493 Michelle Wetterwald contributed extensively the MTU discussion, 494 offered the ETSI ITS perspective, and reviewed other parts of the 495 document. 497 8. Acknowledgements 499 The authors would like to thank Witold Klaudel, Ryuji Wakikawa, 500 Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan 501 Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray 502 Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, 503 Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne, 504 Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark, 505 Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley, Sandra 506 Cespedes, Mariano Falcitelli, Sri Gundavelli, Abdussalam Baryun, 507 Margaret Cullen, Erik Kline and William Whyte. Their valuable 508 comments clarified particular issues and generally helped to improve 509 the document. 511 Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB 512 drivers for linux and described how. 514 For the multicast discussion, the authors would like to thank Owen 515 DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and 516 participants to discussions in network working groups. 518 The authors would like to thank participants to the Birds-of- 519 a-Feather "Intelligent Transportation Systems" meetings held at IETF 520 in 2016. 522 9. References 524 9.1. Normative References 526 [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission 527 of IP datagrams over IEEE 802 networks", STD 43, RFC 1042, 528 DOI 10.17487/RFC1042, February 1988, 529 . 531 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 532 Requirement Levels", BCP 14, RFC 2119, 533 DOI 10.17487/RFC2119, March 1997, 534 . 536 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 537 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 538 . 540 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 541 DOI 10.17487/RFC2818, May 2000, 542 . 544 [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related 545 Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, 546 . 548 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 549 "SEcure Neighbor Discovery (SEND)", RFC 3971, 550 DOI 10.17487/RFC3971, March 2005, 551 . 553 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 554 "Randomness Requirements for Security", BCP 106, RFC 4086, 555 DOI 10.17487/RFC4086, June 2005, 556 . 558 [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, 559 "Internet X.509 Public Key Infrastructure Certificate 560 Management Protocol (CMP)", RFC 4210, 561 DOI 10.17487/RFC4210, September 2005, 562 . 564 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 565 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 566 December 2005, . 568 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 569 DOI 10.17487/RFC4302, December 2005, 570 . 572 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 573 RFC 4303, DOI 10.17487/RFC4303, December 2005, 574 . 576 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 577 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 578 DOI 10.17487/RFC4861, September 2007, 579 . 581 [RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast 582 Extensions to the Security Architecture for the Internet 583 Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008, 584 . 586 [RFC5415] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, 587 Ed., "Control And Provisioning of Wireless Access Points 588 (CAPWAP) Protocol Specification", RFC 5415, 589 DOI 10.17487/RFC5415, March 2009, 590 . 592 [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing 593 Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889, 594 September 2010, . 596 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 597 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 598 2011, . 600 [RFC7042] Eastlake 3rd, D. and J. Abley, "IANA Considerations and 601 IETF Protocol and Documentation Usage for IEEE 802 602 Parameters", BCP 141, RFC 7042, DOI 10.17487/RFC7042, 603 October 2013, . 605 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 606 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 607 February 2014, . 609 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 610 Interface Identifiers with IPv6 Stateless Address 611 Autoconfiguration (SLAAC)", RFC 7217, 612 DOI 10.17487/RFC7217, April 2014, 613 . 615 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 616 Considerations for IPv6 Address Generation Mechanisms", 617 RFC 7721, DOI 10.17487/RFC7721, March 2016, 618 . 620 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 621 "Recommendation on Stable IPv6 Interface Identifiers", 622 RFC 8064, DOI 10.17487/RFC8064, February 2017, 623 . 625 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 626 (IPv6) Specification", STD 86, RFC 8200, 627 DOI 10.17487/RFC8200, July 2017, 628 . 630 9.2. Informative References 632 [ETSI-IPv6-GeoNetworking] 633 "ETSI EN 302 636-6-1 v1.2.1 (2014-05), ETSI, European 634 Standard, Intelligent Transportation Systems (ITS); 635 Vehicular Communications; Geonetworking; Part 6: Internet 636 Integration; Sub-part 1: Transmission of IPv6 Packets over 637 Geonetworking Protocols. Downloaded on September 9th, 638 2017, freely available from ETSI website at URL 639 http://www.etsi.org/deliver/ 640 etsi_en/302600_302699/30263601/01.02.01_60/ 641 en_30263601v010201p.pdf". 643 [ETSI-sec-archi] 644 "ETSI TS 102 940 V1.2.1 (2016-11), ETSI Technical 645 Specification, Intelligent Transport Systems (ITS); 646 Security; ITS communications security architecture and 647 security management, November 2016. Downloaded on 648 September 9th, 2017, freely available from ETSI website at 649 URL http://www.etsi.org/deliver/ 650 etsi_ts/102900_102999/102940/01.02.01_60/ 651 ts_102940v010201p.pdf". 653 [I-D.hinden-6man-rfc2464bis] 654 Crawford, M. and R. Hinden, "Transmission of IPv6 Packets 655 over Ethernet Networks", draft-hinden-6man-rfc2464bis-02 656 (work in progress), March 2017. 658 [I-D.ietf-ipwave-vehicular-networking-survey] 659 Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M. 660 Wetterwald, "Survey on IP-based Vehicular Networking for 661 Intelligent Transportation Systems", draft-ietf-ipwave- 662 vehicular-networking-survey-00 (work in progress), July 663 2017. 665 [I-D.ietf-tsvwg-ieee-802-11] 666 Szigeti, T., Henry, J., and F. Baker, "Diffserv to IEEE 667 802.11 Mapping", draft-ietf-tsvwg-ieee-802-11-11 (work in 668 progress), December 2017. 670 [I-D.perkins-intarea-multicast-ieee802] 671 Perkins, C., Stanley, D., Kumari, W., and J. Zuniga, 672 "Multicast Considerations over IEEE 802 Wireless Media", 673 draft-perkins-intarea-multicast-ieee802-03 (work in 674 progress), July 2017. 676 [IEEE-1609.2] 677 "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access 678 in Vehicular Environments (WAVE) -- Security Services for 679 Applications and Management Messages. Example URL 680 http://ieeexplore.ieee.org/document/7426684/ accessed on 681 August 17th, 2017.". 683 [IEEE-1609.3] 684 "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access 685 in Vehicular Environments (WAVE) -- Networking Services. 686 Example URL http://ieeexplore.ieee.org/document/7458115/ 687 accessed on August 17th, 2017.". 689 [IEEE-1609.4] 690 "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access 691 in Vehicular Environments (WAVE) -- Multi-Channel 692 Operation. Example URL 693 http://ieeexplore.ieee.org/document/7435228/ accessed on 694 August 17th, 2017.". 696 [IEEE-802.11-2016] 697 "IEEE Standard 802.11-2016 - IEEE Standard for Information 698 Technology - Telecommunications and information exchange 699 between systems Local and metropolitan area networks - 700 Specific requirements - Part 11: Wireless LAN Medium 701 Access Control (MAC) and Physical Layer (PHY) 702 Specifications. Status - Active Standard. Description 703 retrieved freely on September 12th, 2017, at URL 704 https://standards.ieee.org/findstds/ 705 standard/802.11-2016.html". 707 [IEEE-802.11p-2010] 708 "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information 709 Technology - Telecommunications and information exchange 710 between systems - Local and metropolitan area networks - 711 Specific requirements, Part 11: Wireless LAN Medium Access 712 Control (MAC) and Physical Layer (PHY) Specifications, 713 Amendment 6: Wireless Access in Vehicular Environments; 714 document freely available at URL 715 http://standards.ieee.org/getieee802/ 716 download/802.11p-2010.pdf retrieved on September 20th, 717 2013.". 719 Appendix A. ChangeLog 721 The changes are listed in reverse chronological order, most recent 722 changes appearing at the top of the list. 724 From draft-ietf-ipwave-ipv6-over-80211ocb-14 to draft-ietf-ipwave- 725 ipv6-over-80211ocb-15 727 o Added normative term MUST in two places in section "Ethernet 728 Adaptation Layer". 730 From draft-ietf-ipwave-ipv6-over-80211ocb-13 to draft-ietf-ipwave- 731 ipv6-over-80211ocb-14 733 o Created a new Appendix titled "Extra Terminology" that contains 734 terms DSRC, DSRCS, OBU, RSU as defined outside IETF. Some of them 735 are used in the main Terminology section. 737 o Added two paragraphs explaining that ND and Mobile IPv6 have 738 problems working over 802.11 OCB, yet their adaptations is not 739 specified in this document. 741 From draft-ietf-ipwave-ipv6-over-80211ocb-12 to draft-ietf-ipwave- 742 ipv6-over-80211ocb-13 744 o Substituted "IP-OBU" for "OBRU", and "IP-RSU" for "RSRU" 745 throughout and improved OBU-related definitions in the Terminology 746 section. 748 From draft-ietf-ipwave-ipv6-over-80211ocb-11 to draft-ietf-ipwave- 749 ipv6-over-80211ocb-12 751 o Improved the appendix about "MAC Address Generation" by expressing 752 the technique to be an optional suggestion, not a mandatory 753 mechanism. 755 From draft-ietf-ipwave-ipv6-over-80211ocb-10 to draft-ietf-ipwave- 756 ipv6-over-80211ocb-11 758 o Shortened the paragraph on forming/terminating 802.11-OCB links. 760 o Moved the draft tsvwg-ieee-802-11 to Informative References. 762 From draft-ietf-ipwave-ipv6-over-80211ocb-09 to draft-ietf-ipwave- 763 ipv6-over-80211ocb-10 765 o Removed text requesting a new Group ID for multicast for OCB. 767 o Added a clarification of the meaning of value "3333" in the 768 section Address Mapping -- Multicast. 770 o Added note clarifying that in Europe the regional authority is not 771 ETSI, but "ECC/CEPT based on ENs from ETSI". 773 o Added note stating that the manner in which two STAtions set their 774 communication channel is not described in this document. 776 o Added a time qualifier to state that the "each node is represented 777 uniquely at a certain point in time." 779 o Removed text "This section may need to be moved" (the "Reliability 780 Requirements" section). This section stays there at this time. 782 o In the term definition "802.11-OCB" added a note stating that "any 783 implementation should comply with standards and regulations set in 784 the different countries for using that frequency band." 786 o In the RSU term definition, added a sentence explaining the 787 difference between RSU and RSRU: in terms of number of interfaces 788 and IP forwarding. 790 o Replaced "with at least two IP interfaces" with "with at least two 791 real or virtual IP interfaces". 793 o Added a term in the Terminology for "OBU". However the definition 794 is left empty, as this term is defined outside IETF. 796 o Added a clarification that it is an OBU or an OBRU in this phrase 797 "A vehicle embarking an OBU or an OBRU". 799 o Checked the entire document for a consistent use of terms OBU and 800 OBRU. 802 o Added note saying that "'p' is a letter identifying the 803 Ammendment". 805 o Substituted lower case for capitals SHALL or MUST in the 806 Appendices. 808 o Added reference to RFC7042, helpful in the 3333 explanation. 809 Removed reference to individual submission draft-petrescu-its- 810 scenario-reqs and added reference to draft-ietf-ipwave-vehicular- 811 networking-survey. 813 o Added figure captions, figure numbers, and references to figure 814 numbers instead of 'below'. Replaced "section Section" with 815 "section" throughout. 817 o Minor typographical errors. 819 From draft-ietf-ipwave-ipv6-over-80211ocb-08 to draft-ietf-ipwave- 820 ipv6-over-80211ocb-09 822 o Significantly shortened the Address Mapping sections, by text 823 copied from RFC2464, and rather referring to it. 825 o Moved the EPD description to an Appendix on its own. 827 o Shortened the Introduction and the Abstract. 829 o Moved the tutorial section of OCB mode introduced to .11, into an 830 appendix. 832 o Removed the statement that suggests that for routing purposes a 833 prefix exchange mechanism could be needed. 835 o Removed refs to RFC3963, RFC4429 and RFC6775; these are about ND, 836 MIP/NEMO and oDAD; they were referred in the handover discussion 837 section, which is out. 839 o Updated a reference from individual submission to now a WG item in 840 IPWAVE: the survey document. 842 o Added term definition for WiFi. 844 o Updated the authorship and expanded the Contributors section. 846 o Corrected typographical errors. 848 From draft-ietf-ipwave-ipv6-over-80211ocb-07 to draft-ietf-ipwave- 849 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-02 981 o Replaced almost all occurences of 802.11p with 802.11-OCB, leaving 982 only when explanation of evolution was necessary. 984 o Shortened by removing parameter details from a paragraph in the 985 Introduction. 987 o Moved a reference from Normative to Informative. 989 o Added text in intro clarifying there is no handover spec at IEEE, 990 and that 1609.2 does provide security services. 992 o Named the contents the fields of the EthernetII header (including 993 the Ethertype bitstring). 995 o Improved relationship between two paragraphs describing the 996 increase of the Sequence Number in 802.11 header upon IP 997 fragmentation. 999 o Added brief clarification of "tracking". 1001 From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave- 1002 ipv6-over-80211ocb-01 1004 o Introduced message exchange diagram illustrating differences 1005 between 802.11 and 802.11 in OCB mode. 1007 o Introduced an appendix listing for information the set of 802.11 1008 messages that may be transmitted in OCB mode. 1010 o Removed appendix sections "Privacy Requirements", "Authentication 1011 Requirements" and "Security Certificate Generation". 1013 o Removed appendix section "Non IP Communications". 1015 o Introductory phrase in the Security Considerations section. 1017 o Improved the definition of "OCB". 1019 o Introduced theoretical stacked layers about IPv6 and IEEE layers 1020 including EPD. 1022 o Removed the appendix describing the details of prohibiting IPv6 on 1023 certain channels relevant to 802.11-OCB. 1025 o Added a brief reference in the privacy text about a precise clause 1026 in IEEE 1609.3 and .4. 1028 o Clarified the definition of a Road Side Unit. 1030 o Removed the discussion about security of WSA (because is non-IP). 1032 o Removed mentioning of the GeoNetworking discussion. 1034 o Moved references to scientific articles to a separate 'overview' 1035 draft, and referred to it. 1037 Appendix B. 802.11p 1039 The term "802.11p" is an earlier definition. The behaviour of 1040 "802.11p" networks is rolled in the document IEEE Std 802.11-2016. 1041 In that document the term 802.11p disappears. Instead, each 802.11p 1042 feature is conditioned by the Management Information Base (MIB) 1043 attribute "OCBActivated". Whenever OCBActivated is set to true the 1044 IEEE Std 802.11 OCB state is activated. For example, an 802.11 1045 STAtion operating outside the context of a basic service set has the 1046 OCBActivated flag set. Such a station, when it has the flag set, 1047 uses a BSS identifier equal to ff:ff:ff:ff:ff:ff. 1049 Appendix C. Aspects introduced by the OCB mode to 802.11 1051 In the IEEE 802.11-OCB mode, all nodes in the wireless range can 1052 directly communicate with each other without involving authentication 1053 or association procedures. At link layer, it is necessary to set the 1054 same channel number (or frequency) on two stations that need to 1055 communicate with each other. The manner in which stations set their 1056 channel number is not specified in this document. Stations STA1 and 1057 STA2 can exchange IP packets if they are set on the same channel. At 1058 IP layer, they then discover each other by using the IPv6 Neighbor 1059 Discovery protocol. 1061 Briefly, the IEEE 802.11-OCB mode has the following properties: 1063 o The use by each node of a 'wildcard' BSSID (i.e., each bit of the 1064 BSSID is set to 1) 1066 o No IEEE 802.11 Beacon frames are transmitted 1068 o No authentication is required in order to be able to communicate 1070 o No association is needed in order to be able to communicate 1072 o No encryption is provided in order to be able to communicate 1074 o Flag dot11OCBActivated is set to true 1076 All the nodes in the radio communication range (IP-OBU and IP-RSU) 1077 receive all the messages transmitted (IP-OBU and IP-RSU) within the 1078 radio communications range. The eventual conflict(s) are resolved by 1079 the MAC CDMA function. 1081 The message exchange diagram in Figure 4 illustrates a comparison 1082 between traditional 802.11 and 802.11 in OCB mode. The 'Data' 1083 messages can be IP packets such as HTTP or others. Other 802.11 1084 management and control frames (non IP) may be transmitted, as 1085 specified in the 802.11 standard. For information, the names of 1086 these messages as currently specified by the 802.11 standard are 1087 listed in Appendix G. 1089 STA AP STA1 STA2 1090 | | | | 1091 |<------ Beacon -------| |<------ Data -------->| 1092 | | | | 1093 |---- Probe Req. ----->| |<------ Data -------->| 1094 |<--- Probe Res. ------| | | 1095 | | |<------ Data -------->| 1096 |---- Auth Req. ------>| | | 1097 |<--- Auth Res. -------| |<------ Data -------->| 1098 | | | | 1099 |---- Asso Req. ------>| |<------ Data -------->| 1100 |<--- Asso Res. -------| | | 1101 | | |<------ Data -------->| 1102 |<------ Data -------->| | | 1103 |<------ Data -------->| |<------ Data -------->| 1105 (i) 802.11 Infrastructure mode (ii) 802.11-OCB mode 1107 Figure 4: Difference between messages exchanged on 802.11 (left) and 1108 802.11-OCB (right) 1110 The interface 802.11-OCB was specified in IEEE Std 802.11p (TM) -2010 1111 [IEEE-802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, 1112 titled "Amendment 6: Wireless Access in Vehicular Environments". 1113 Since then, this amendment has been integrated in IEEE 802.11(TM) 1114 -2012 and -2016 [IEEE-802.11-2016]. 1116 In document 802.11-2016, anything qualified specifically as 1117 "OCBActivated", or "outside the context of a basic service" set to be 1118 true, then it is actually referring to OCB aspects introduced to 1119 802.11. 1121 In order to delineate the aspects introduced by 802.11-OCB to 802.11, 1122 we refer to the earlier [IEEE-802.11p-2010]. The amendment is 1123 concerned with vehicular communications, where the wireless link is 1124 similar to that of Wireless LAN (using a PHY layer specified by 1125 802.11a/b/g/n), but which needs to cope with the high mobility factor 1126 inherent in scenarios of communications between moving vehicles, and 1127 between vehicles and fixed infrastructure deployed along roads. 1128 While 'p' is a letter identifying the Ammendment, just like 'a, b, g' 1129 and 'n' are, 'p' is concerned more with MAC modifications, and a 1130 little with PHY modifications; the others are mainly about PHY 1131 modifications. It is possible in practice to combine a 'p' MAC with 1132 an 'a' PHY by operating outside the context of a BSS with OFDM at 1133 5.4GHz and 5.9GHz. 1135 The 802.11-OCB links are specified to be compatible as much as 1136 possible with the behaviour of 802.11a/b/g/n and future generation 1137 IEEE WLAN links. From the IP perspective, an 802.11-OCB MAC layer 1138 offers practically the same interface to IP as the WiFi and Ethernet 1139 layers do (802.11a/b/g/n and 802.3). A packet sent by an IP-OBU may 1140 be received by one or multiple IP-RSUs. The link-layer resolution is 1141 performed by using the IPv6 Neighbor Discovery protocol. 1143 To support this similarity statement (IPv6 is layered on top of LLC 1144 on top of 802.11-OCB, in the same way that IPv6 is layered on top of 1145 LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on 1146 top of 802.3 (for Ethernet)) it is useful to analyze the differences 1147 between 802.11-OCB and 802.11 specifications. During this analysis, 1148 we note that whereas 802.11-OCB lists relatively complex and numerous 1149 changes to the MAC layer (and very little to the PHY layer), there 1150 are only a few characteristics which may be important for an 1151 implementation transmitting IPv6 packets on 802.11-OCB links. 1153 The most important 802.11-OCB point which influences the IPv6 1154 functioning is the OCB characteristic; an additional, less direct 1155 influence, is the maximum bandwidth afforded by the PHY modulation/ 1156 demodulation methods and channel access specified by 802.11-OCB. The 1157 maximum bandwidth theoretically possible in 802.11-OCB is 54 Mbit/s 1158 (when using, for example, the following parameters: 20 MHz channel; 1159 modulation 64-QAM; coding rate R is 3/4); in practice of IP-over- 1160 802.11-OCB a commonly observed figure is 12Mbit/s; this bandwidth 1161 allows the operation of a wide range of protocols relying on IPv6. 1163 o Operation Outside the Context of a BSS (OCB): the (earlier 1164 802.11p) 802.11-OCB links are operated without a Basic Service Set 1165 (BSS). This means that the frames IEEE 802.11 Beacon, Association 1166 Request/Response, Authentication Request/Response, and similar, 1167 are not used. The used identifier of BSS (BSSID) has a 1168 hexadecimal value always 0xffffffffffff (48 '1' bits, represented 1169 as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' 1170 BSSID), as opposed to an arbitrary BSSID value set by 1171 administrator (e.g. 'My-Home-AccessPoint'). The OCB operation - 1172 namely the lack of beacon-based scanning and lack of 1173 authentication - should be taken into account when the Mobile IPv6 1174 protocol [RFC6275] and the protocols for IP layer security 1175 [RFC4301] are used. The way these protocols adapt to OCB is not 1176 described in this document. 1178 o Timing Advertisement: is a new message defined in 802.11-OCB, 1179 which does not exist in 802.11a/b/g/n. This message is used by 1180 stations to inform other stations about the value of time. It is 1181 similar to the time as delivered by a GNSS system (Galileo, GPS, 1182 ...) or by a cellular system. This message is optional for 1183 implementation. 1185 o Frequency range: this is a characteristic of the PHY layer, with 1186 almost no impact on the interface between MAC and IP. However, it 1187 is worth considering that the frequency range is regulated by a 1188 regional authority (ARCEP, ECC/CEPT based on ENs from ETSI, FCC, 1189 etc.); as part of the regulation process, specific applications 1190 are associated with specific frequency ranges. In the case of 1191 802.11-OCB, the regulator associates a set of frequency ranges, or 1192 slots within a band, to the use of applications of vehicular 1193 communications, in a band known as "5.9GHz". The 5.9GHz band is 1194 different from the 2.4GHz and 5GHz bands used by Wireless LAN. 1195 However, as with Wireless LAN, the operation of 802.11-OCB in 1196 "5.9GHz" bands is exempt from owning a license in EU (in US the 1197 5.9GHz is a licensed band of spectrum; for the fixed 1198 infrastructure an explicit FCC authorization is required; for an 1199 on-board device a 'licensed-by-rule' concept applies: rule 1200 certification conformity is required.) Technical conditions are 1201 different than those of the bands "2.4GHz" or "5GHz". The allowed 1202 power levels, and implicitly the maximum allowed distance between 1203 vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20 1204 dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum 1205 distance of approximately 1km, compared to approximately 50m. 1206 Additionally, specific conditions related to congestion avoidance, 1207 jamming avoidance, and radar detection are imposed on the use of 1208 DSRC (in US) and on the use of frequencies for Intelligent 1209 Transportation Systems (in EU), compared to Wireless LAN 1210 (802.11a/b/g/n). 1212 o 'Half-rate' encoding: as the frequency range, this parameter is 1213 related to PHY, and thus has not much impact on the interface 1214 between the IP layer and the MAC layer. 1216 o In vehicular communications using 802.11-OCB links, there are 1217 strong privacy requirements with respect to addressing. While the 1218 802.11-OCB standard does not specify anything in particular with 1219 respect to MAC addresses, in these settings there exists a strong 1220 need for dynamic change of these addresses (as opposed to the non- 1221 vehicular settings - real wall protection - where fixed MAC 1222 addresses do not currently pose some privacy risks). This is 1223 further described in Section 5. A relevant function is described 1224 in IEEE 1609.3-2016 [IEEE-1609.3], clause 5.5.1 and IEEE 1225 1609.4-2016 [IEEE-1609.4], clause 6.7. 1227 Other aspects particular to 802.11-OCB, which are also particular to 1228 802.11 (e.g. the 'hidden node' operation), may have an influence on 1229 the use of transmission of IPv6 packets on 802.11-OCB networks. The 1230 OCB subnet structure is described in Section 4.6. 1232 Appendix D. Changes Needed on a software driver 802.11a to become a 1233 802.11-OCB driver 1235 The 802.11p amendment modifies both the 802.11 stack's physical and 1236 MAC layers but all the induced modifications can be quite easily 1237 obtained by modifying an existing 802.11a ad-hoc stack. 1239 Conditions for a 802.11a hardware to be 802.11-OCB compliant: 1241 o The PHY entity shall be an orthogonal frequency division 1242 multiplexing (OFDM) system. It must support the frequency bands 1243 on which the regulator recommends the use of ITS communications, 1244 for example using IEEE 802.11-OCB layer, in France: 5875MHz to 1245 5925MHz. 1247 o The OFDM system must provide a "half-clocked" operation using 10 1248 MHz channel spacings. 1250 o The chip transmit spectrum mask must be compliant to the "Transmit 1251 spectrum mask" from the IEEE 802.11p amendment (but experimental 1252 environments tolerate otherwise). 1254 o The chip should be able to transmit up to 44.8 dBm when used by 1255 the US government in the United States, and up to 33 dBm in 1256 Europe; other regional conditions apply. 1258 Changes needed on the network stack in OCB mode: 1260 o Physical layer: 1262 * The chip must use the Orthogonal Frequency Multiple Access 1263 (OFDM) encoding mode. 1265 * The chip must be set in half-mode rate mode (the internal clock 1266 frequency is divided by two). 1268 * The chip must use dedicated channels and should allow the use 1269 of higher emission powers. This may require modifications to 1270 the local computer file that describes regulatory domains 1271 rules, if used by the kernel to enforce local specific 1272 restrictions. Such modifications to the local computer file 1273 must respect the location-specific regulatory rules. 1275 MAC layer: 1277 * All management frames (beacons, join, leave, and others) 1278 emission and reception must be disabled except for frames of 1279 subtype Action and Timing Advertisement (defined below). 1281 * No encryption key or method must be used. 1283 * Packet emission and reception must be performed as in ad-hoc 1284 mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff). 1286 * The functions related to joining a BSS (Association Request/ 1287 Response) and for authentication (Authentication Request/Reply, 1288 Challenge) are not called. 1290 * The beacon interval is always set to 0 (zero). 1292 * Timing Advertisement frames, defined in the amendment, should 1293 be supported. The upper layer should be able to trigger such 1294 frames emission and to retrieve information contained in 1295 received Timing Advertisements. 1297 Appendix E. EtherType Protocol Discrimination (EPD) 1299 A more theoretical and detailed view of layer stacking, and 1300 interfaces between the IP layer and 802.11-OCB layers, is illustrated 1301 in Figure 5. The IP layer operates on top of the EtherType Protocol 1302 Discrimination (EPD); this Discrimination layer is described in IEEE 1303 Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP 1304 (Link Layer Control Service Access Point). 1306 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1307 | IPv6 | 1308 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ 1309 { LLC_SAP } 802.11-OCB 1310 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary 1311 | EPD | | | 1312 | | MLME | | 1313 +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | 1314 | MAC Sublayer | | | 802.11-OCB 1315 | and ch. coord. | | SME | Services 1316 +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | 1317 | | PLME | | 1318 | PHY Layer | PLME_SAP | 1319 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1321 Figure 5: EtherType Protocol Discrimination 1323 Appendix F. Design Considerations 1325 The networks defined by 802.11-OCB are in many ways similar to other 1326 networks of the 802.11 family. In theory, the encapsulation of IPv6 1327 over 802.11-OCB could be very similar to the operation of IPv6 over 1328 other networks of the 802.11 family. However, the high mobility, 1329 strong link asymmetry and very short connection makes the 802.11-OCB 1330 link significantly different from other 802.11 networks. Also, the 1331 automotive applications have specific requirements for reliability, 1332 security and privacy, which further add to the particularity of the 1333 802.11-OCB link. 1335 F.1. Vehicle ID 1337 In automotive networks it is required that each node is represented 1338 uniquely at a certain point in time. Accordingly, a vehicle must be 1339 identified by at least one unique identifier. The current 1340 specification at ETSI and at IEEE 1609 identifies a vehicle by its 1341 MAC address, which is obtained from the 802.11-OCB Network Interface 1342 Card (NIC). 1344 In case multiple 802.11-OCB NICs are present in one car, implicitely 1345 multiple vehicle IDs will be generated. Additionally, some software 1346 generates a random MAC address each time the computer boots; this 1347 constitutes an additional difficulty. 1349 A mechanim to uniquely identify a vehicle irrespectively to the 1350 multiplicity of NICs, or frequent MAC address generation, is 1351 necessary. 1353 F.2. Reliability Requirements 1355 The dynamically changing topology, short connectivity, mobile 1356 transmitter and receivers, different antenna heights, and many-to- 1357 many communication types, make IEEE 802.11-OCB links significantly 1358 different from other IEEE 802.11 links. Any IPv6 mechanism operating 1359 on IEEE 802.11-OCB link must support strong link asymmetry, spatio- 1360 temporal link quality, fast address resolution and transmission. 1362 IEEE 802.11-OCB strongly differs from other 802.11 systems to operate 1363 outside of the context of a Basic Service Set. This means in 1364 practice that IEEE 802.11-OCB does not rely on a Base Station for all 1365 Basic Service Set management. In particular, IEEE 802.11-OCB shall 1366 not use beacons. Any IPv6 mechanism requiring L2 services from IEEE 1367 802.11 beacons must support an alternative service. 1369 Channel scanning being disabled, IPv6 over IEEE 802.11-OCB must 1370 implement a mechanism for transmitter and receiver to converge to a 1371 common channel. 1373 Authentication not being possible, IPv6 over IEEE 802.11-OCB must 1374 implement an distributed mechanism to authenticate transmitters and 1375 receivers without the support of a DHCP server. 1377 Time synchronization not being available, IPv6 over IEEE 802.11-OCB 1378 must implement a higher layer mechanism for time synchronization 1379 between transmitters and receivers without the support of a NTP 1380 server. 1382 The IEEE 802.11-OCB link being asymmetric, IPv6 over IEEE 802.11-OCB 1383 must disable management mechanisms requesting acknowledgements or 1384 replies. 1386 The IEEE 802.11-OCB link having a short duration time, IPv6 over IEEE 1387 802.11-OCB should implement fast IPv6 mobility management mechanisms. 1389 F.3. Multiple interfaces 1391 There are considerations for 2 or more IEEE 802.11-OCB interface 1392 cards per vehicle. For each vehicle taking part in road traffic, one 1393 IEEE 802.11-OCB interface card could be fully allocated for Non IP 1394 safety-critical communication. Any other IEEE 802.11-OCB may be used 1395 for other type of traffic. 1397 The mode of operation of these other wireless interfaces is not 1398 clearly defined yet. One possibility is to consider each card as an 1399 independent network interface, with a specific MAC Address and a set 1400 of IPv6 addresses. Another possibility is to consider the set of 1401 these wireless interfaces as a single network interface (not 1402 including the IEEE 802.11-OCB interface used by Non IP safety 1403 critical communications). This will require specific logic to 1404 ensure, for example, that packets meant for a vehicle in front are 1405 actually sent by the radio in the front, or that multiple copies of 1406 the same packet received by multiple interfaces are treated as a 1407 single packet. Treating each wireless interface as a separate 1408 network interface pushes such issues to the application layer. 1410 Certain privacy requirements imply that if these multiple interfaces 1411 are represented by many network interface, a single renumbering event 1412 shall cause renumbering of all these interfaces. If one MAC changed 1413 and another stayed constant, external observers would be able to 1414 correlate old and new values, and the privacy benefits of 1415 randomization would be lost. 1417 The privacy requirements of Non IP safety-critical communications 1418 imply that if a change of pseudonyme occurs, renumbering of all other 1419 interfaces shall also occur. 1421 F.4. MAC Address Generation 1423 In 802.11-OCB networks, the MAC addresses may change during well 1424 defined renumbering events. A 'randomized' MAC address has the 1425 following characteristics: 1427 o Bit "Local/Global" set to "locally admninistered". 1429 o Bit "Unicast/Multicast" set to "Unicast". 1431 o The 46 remaining bits are set to a random value, using a random 1432 number generator that meets the requirements of [RFC4086]. 1434 To meet the randomization requirements for the 46 remaining bits, a 1435 hash function may be used. For example, the SHA256 hash function may 1436 be used with input a 256 bit local secret, the "nominal" MAC Address 1437 of the interface, and a representation of the date and time of the 1438 renumbering event. 1440 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode 1442 For information, at the time of writing, this is the list of IEEE 1443 802.11 messages that may be transmitted in OCB mode, i.e. when 1444 dot11OCBActivated is true in a STA: 1446 o The STA may send management frames of subtype Action and, if the 1447 STA maintains a TSF Timer, subtype Timing Advertisement; 1449 o The STA may send control frames, except those of subtype PS-Poll, 1450 CF-End, and CF-End plus CFAck; 1452 o The STA may send data frames of subtype Data, Null, QoS Data, and 1453 QoS Null. 1455 Appendix H. Implementation Status 1457 This section describes an example of an IPv6 Packet captured over a 1458 IEEE 802.11-OCB link. 1460 By way of example we show that there is no modification in the 1461 headers when transmitted over 802.11-OCB networks - they are 1462 transmitted like any other 802.11 and Ethernet packets. 1464 We describe an experiment of capturing an IPv6 packet on an 1465 802.11-OCB link. In topology depicted in Figure 6, the packet is an 1466 IPv6 Router Advertisement. This packet is emitted by a Router on its 1467 802.11-OCB interface. The packet is captured on the Host, using a 1468 network protocol analyzer (e.g. Wireshark); the capture is performed 1469 in two different modes: direct mode and 'monitor' mode. The topology 1470 used during the capture is depicted below. 1472 The packet is captured on the Host. The Host is an IP-OBU containing 1473 an 802.11 interface in format PCI express (an ITRI product). The 1474 kernel runs the ath5k software driver with modifications for OCB 1475 mode. The capture tool is Wireshark. The file format for save and 1476 analyze is 'pcap'. The packet is generated by the Router. The 1477 Router is an IP-RSU (ITRI product). 1479 +--------+ +-------+ 1480 | | 802.11-OCB Link | | 1481 ---| Router |--------------------------------| Host | 1482 | | | | 1483 +--------+ +-------+ 1485 Figure 6: Topology for capturing IP packets on 802.11-OCB 1487 During several capture operations running from a few moments to 1488 several hours, no message relevant to the BSSID contexts were 1489 captured (no Association Request/Response, Authentication Req/Resp, 1490 Beacon). This shows that the operation of 802.11-OCB is outside the 1491 context of a BSSID. 1493 Overall, the captured message is identical with a capture of an IPv6 1494 packet emitted on a 802.11b interface. The contents are precisely 1495 similar. 1497 H.1. Capture in Monitor Mode 1499 The IPv6 RA packet captured in monitor mode is illustrated below. 1500 The radio tap header provides more flexibility for reporting the 1501 characteristics of frames. The Radiotap Header is prepended by this 1502 particular stack and operating system on the Host machine to the RA 1503 packet received from the network (the Radiotap Header is not present 1504 on the air). The implementation-dependent Radiotap Header is useful 1505 for piggybacking PHY information from the chip's registers as data in 1506 a packet understandable by userland applications using Socket 1507 interfaces (the PHY interface can be, for example: power levels, data 1508 rate, ratio of signal to noise). 1510 The packet present on the air is formed by IEEE 802.11 Data Header, 1511 Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. 1513 Radiotap Header v0 1514 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1515 |Header Revision| Header Pad | Header length | 1516 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1517 | Present flags | 1518 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1519 | Data Rate | Pad | 1520 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1522 IEEE 802.11 Data Header 1523 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1524 | Type/Subtype and Frame Ctrl | Duration | 1525 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1526 | Receiver Address... 1527 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1528 ... Receiver Address | Transmitter Address... 1529 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1530 ... Transmitter Address | 1531 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1532 | BSS Id... 1533 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1534 ... BSS Id | Frag Number and Seq Number | 1535 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1537 Logical-Link Control Header 1538 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1539 | DSAP |I| SSAP |C| Control field | Org. code... 1540 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1541 ... Organizational Code | Type | 1542 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1544 IPv6 Base Header 1545 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1546 |Version| Traffic Class | Flow Label | 1547 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1548 | Payload Length | Next Header | Hop Limit | 1549 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1550 | | 1551 + + 1552 | | 1553 + Source Address + 1554 | | 1555 + + 1556 | | 1557 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1558 | | 1559 + + 1560 | | 1561 + Destination Address + 1562 | | 1563 + + 1564 | | 1565 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1567 Router Advertisement 1568 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1569 | Type | Code | Checksum | 1570 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1571 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1572 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1573 | Reachable Time | 1574 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1575 | Retrans Timer | 1576 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1577 | Options ... 1578 +-+-+-+-+-+-+-+-+-+-+-+- 1580 The value of the Data Rate field in the Radiotap header is set to 6 1581 Mb/s. This indicates the rate at which this RA was received. 1583 The value of the Transmitter address in the IEEE 802.11 Data Header 1584 is set to a 48bit value. The value of the destination address is 1585 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS 1586 Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network 1587 protocol analyzer as being "broadcast". The Fragment number and 1588 sequence number fields are together set to 0x90C6. 1590 The value of the Organization Code field in the Logical-Link Control 1591 Header is set to 0x0, recognized as "Encapsulated Ethernet". The 1592 value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise 1593 #86DD), recognized as "IPv6". 1595 A Router Advertisement is periodically sent by the router to 1596 multicast group address ff02::1. It is an icmp packet type 134. The 1597 IPv6 Neighbor Discovery's Router Advertisement message contains an 1598 8-bit field reserved for single-bit flags, as described in [RFC4861]. 1600 The IPv6 header contains the link local address of the router 1601 (source) configured via EUI-64 algorithm, and destination address set 1602 to ff02::1. Recent versions of network protocol analyzers (e.g. 1604 Wireshark) provide additional informations for an IP address, if a 1605 geolocalization database is present. In this example, the 1606 geolocalization database is absent, and the "GeoIP" information is 1607 set to unknown for both source and destination addresses (although 1608 the IPv6 source and destination addresses are set to useful values). 1609 This "GeoIP" can be a useful information to look up the city, 1610 country, AS number, and other information for an IP address. 1612 The Ethernet Type field in the logical-link control header is set to 1613 0x86dd which indicates that the frame transports an IPv6 packet. In 1614 the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 1615 which is the corresponding multicast MAC address. The BSS id is a 1616 broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link 1617 duration between vehicles and the roadside infrastructure, there is 1618 no need in IEEE 802.11-OCB to wait for the completion of association 1619 and authentication procedures before exchanging data. IEEE 1620 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) 1621 and may start communicating as soon as they arrive on the 1622 communication channel. 1624 H.2. Capture in Normal Mode 1626 The same IPv6 Router Advertisement packet described above (monitor 1627 mode) is captured on the Host, in the Normal mode, and depicted 1628 below. 1630 Ethernet II Header 1631 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1632 | Destination... 1633 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1634 ...Destination | Source... 1635 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1636 ...Source | 1637 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1638 | Type | 1639 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1641 IPv6 Base Header 1642 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1643 |Version| Traffic Class | Flow Label | 1644 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1645 | Payload Length | Next Header | Hop Limit | 1646 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1647 | | 1648 + + 1649 | | 1650 + Source Address + 1651 | | 1652 + + 1653 | | 1654 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1655 | | 1656 + + 1657 | | 1658 + Destination Address + 1659 | | 1660 + + 1661 | | 1662 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1664 Router Advertisement 1665 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1666 | Type | Code | Checksum | 1667 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1668 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1669 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1670 | Reachable Time | 1671 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1672 | Retrans Timer | 1673 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1674 | Options ... 1675 +-+-+-+-+-+-+-+-+-+-+-+- 1677 One notices that the Radiotap Header, the IEEE 802.11 Data Header and 1678 the Logical-Link Control Headers are not present. On the other hand, 1679 a new header named Ethernet II Header is present. 1681 The Destination and Source addresses in the Ethernet II header 1682 contain the same values as the fields Receiver Address and 1683 Transmitter Address present in the IEEE 802.11 Data Header in the 1684 "monitor" mode capture. 1686 The value of the Type field in the Ethernet II header is 0x86DD 1687 (recognized as "IPv6"); this value is the same value as the value of 1688 the field Type in the Logical-Link Control Header in the "monitor" 1689 mode capture. 1691 The knowledgeable experimenter will no doubt notice the similarity of 1692 this Ethernet II Header with a capture in normal mode on a pure 1693 Ethernet cable interface. 1695 An Adaptation layer is inserted on top of a pure IEEE 802.11 MAC 1696 layer, in order to adapt packets, before delivering the payload data 1697 to the applications. It adapts 802.11 LLC/MAC headers to Ethernet II 1698 headers. In further detail, this adaptation consists in the 1699 elimination of the Radiotap, 802.11 and LLC headers, and in the 1700 insertion of the Ethernet II header. In this way, IPv6 runs straight 1701 over LLC over the 802.11-OCB MAC layer; this is further confirmed by 1702 the use of the unique Type 0x86DD. 1704 Appendix I. Extra Terminology 1706 The following terms are defined outside the IETF. They are used to 1707 define the main terms in the main terminology section Section 2. 1709 DSRC (Dedicated Short Range Communication): a term defined outside 1710 the IETF. The US Federal Communications Commission (FCC) Dedicated 1711 Short Range Communication (DSRC) is defined in the Code of Federal 1712 Regulations (CFR) 47, Parts 90 and 95. This Code is referred in the 1713 definitions below. At the time of the writing of this Internet 1714 Draft, the last update of this Code was dated October 1st, 2010. 1716 DSRCS (Dedicated Short-Range Communications Services): a term defined 1717 outside the IETF. The use of radio techniques to transfer data over 1718 short distances between roadside and mobile units, between mobile 1719 units, and between portable and mobile units to perform operations 1720 related to the improvement of traffic flow, traffic safety, and other 1721 intelligent transportation service applications in a variety of 1722 environments. DSRCS systems may also transmit status and 1723 instructional messages related to the units involve. [Ref. 47 CFR 1724 90.7 - Definitions] 1725 OBU (On-Board Unit): a term defined outside the IETF. An On-Board 1726 Unit is a DSRCS transceiver that is normally mounted in or on a 1727 vehicle, or which in some instances may be a portable unit. An OBU 1728 can be operational while a vehicle or person is either mobile or 1729 stationary. The OBUs receive and contend for time to transmit on one 1730 or more radio frequency (RF) channels. Except where specifically 1731 excluded, OBU operation is permitted wherever vehicle operation or 1732 human passage is permitted. The OBUs mounted in vehicles are 1733 licensed by rule under part 95 of the respective chapter and 1734 communicate with Roadside Units (RSUs) and other OBUs. Portable OBUs 1735 are also licensed by rule under part 95 of the respective chapter. 1736 OBU operations in the Unlicensed National Information Infrastructure 1737 (UNII) Bands follow the rules in those bands. - [CFR 90.7 - 1738 Definitions]. 1740 RSU (Road-Side Unit): a term defined outside of IETF. A Roadside 1741 Unit is a DSRC transceiver that is mounted along a road or pedestrian 1742 passageway. An RSU may also be mounted on a vehicle or is hand 1743 carried, but it may only operate when the vehicle or hand- carried 1744 unit is stationary. Furthermore, an RSU operating under the 1745 respectgive part is restricted to the location where it is licensed 1746 to operate. However, portable or hand-held RSUs are permitted to 1747 operate where they do not interfere with a site-licensed operation. 1748 A RSU broadcasts data to OBUs or exchanges data with OBUs in its 1749 communications zone. An RSU also provides channel assignments and 1750 operating instructions to OBUs in its communications zone, when 1751 required. - [CFR 90.7 - Definitions]. 1753 Authors' Addresses 1755 Alexandre Petrescu 1756 CEA, LIST 1757 CEA Saclay 1758 Gif-sur-Yvette , Ile-de-France 91190 1759 France 1761 Phone: +33169089223 1762 Email: Alexandre.Petrescu@cea.fr 1764 Nabil Benamar 1765 Moulay Ismail University 1766 Morocco 1768 Phone: +212670832236 1769 Email: n.benamar@est.umi.ac.ma 1770 Jerome Haerri 1771 Eurecom 1772 Sophia-Antipolis 06904 1773 France 1775 Phone: +33493008134 1776 Email: Jerome.Haerri@eurecom.fr 1778 Jong-Hyouk Lee 1779 Sangmyung University 1780 31, Sangmyeongdae-gil, Dongnam-gu 1781 Cheonan 31066 1782 Republic of Korea 1784 Email: jonghyouk@smu.ac.kr 1786 Thierry Ernst 1787 YoGoKo 1788 France 1790 Email: thierry.ernst@yogoko.fr