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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: April 19, 2018 Moulay Ismail University 6 J. Haerri 7 Eurecom 8 J. Lee 9 Sangmyung University 10 T. Ernst 11 YoGoKo 12 October 16, 2017 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-11.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 April 19, 2018. 47 Copyright Notice 49 Copyright (c) 2017 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (https://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with respect 57 to this document. Code Components extracted from this document must 58 include Simplified BSD License text as described in Section 4.e of 59 the Trust Legal Provisions and are provided without warranty as 60 described in the Simplified BSD License. 62 Table of Contents 64 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 65 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 66 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 5 67 4. IPv6 over 802.11-OCB . . . . . . . . . . . . . . . . . . . . 5 68 4.1. Maximum Transmission Unit (MTU) . . . . . . . . . . . . . 5 69 4.2. Frame Format . . . . . . . . . . . . . . . . . . . . . . 5 70 4.2.1. Ethernet Adaptation Layer . . . . . . . . . . . . . . 6 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 . . . . . . . . . . . . . . . 9 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 . . . . 22 87 Appendix D. Changes Needed on a software driver 802.11a to 88 become a 802.11-OCB driver . . . 26 89 Appendix E. EtherType Protocol Discrimination (EPD) . . . . . . 27 90 Appendix F. Design Considerations . . . . . . . . . . . . . . . 28 91 F.1. Vehicle ID . . . . . . . . . . . . . . . . . . . . . . . 28 92 F.2. Reliability Requirements . . . . . . . . . . . . . . . . 29 93 F.3. Multiple interfaces . . . . . . . . . . . . . . . . . . . 29 94 F.4. MAC Address Generation . . . . . . . . . . . . . . . . . 30 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 . . . . . . . . . . . . . . . . . 34 100 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36 102 1. Introduction 104 This document describes the transmission of IPv6 packets on IEEE Std 105 802.11-OCB networks [IEEE-802.11-2016] (a.k.a "802.11p" see 106 Appendix B). This involves the layering of IPv6 networking on top of 107 the IEEE 802.11 MAC layer, with an LLC layer. Compared to running 108 IPv6 over the Ethernet MAC layer, there is no modification expected 109 to IEEE Std 802.11 MAC and Logical Link sublayers: IPv6 works fine 110 directly over 802.11-OCB too, with an LLC layer. 112 The IPv6 network layer operates on 802.11-OCB in the same manner as 113 operating on Ethernet, but there are two kinds of exceptions: 115 o Exceptions due to different operation of IPv6 network layer on 116 802.11 than on Ethernet. To satisfy these exceptions, this 117 document describes an Ethernet Adaptation Layer between Ethernet 118 headers and 802.11 headers. The Ethernet Adaptation Layer is 119 described Section 4.2.1. The operation of IP on Ethernet is 120 described in [RFC1042], [RFC2464] and 121 [I-D.hinden-6man-rfc2464bis]. 123 o Exceptions due to the OCB nature of 802.11-OCB compared to 802.11. 124 This has impacts on security, privacy, subnet structure and 125 handover behaviour. For security and privacy recommendations see 126 Section 5 and Section 4.5. The subnet structure is described in 127 Section 4.6. The handover behaviour on OCB links is not described 128 in this document. 130 In the published literature, many documents describe aspects and 131 problems related to running IPv6 over 802.11-OCB: 132 [I-D.ietf-ipwave-vehicular-networking-survey]. 134 2. Terminology 136 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 137 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 138 document are to be interpreted as described in RFC 2119 [RFC2119]. 140 WiFi: Wireless Fidelity. 142 OBRU (On-Board Router Unit): an OBRU is almost always situated in a 143 vehicle; it is a computer with at least two IP real or virtual 144 interfaces; at least one IP interface runs in OCB mode of 802.11. It 145 MAY be an IP Router. 147 OBU (On-Board Unit): term defined outside the IETF. 149 RSRU (Road-Side Router Unit): an RSRU is almost always situated in a 150 box fixed along the road. An RSRU has at least two distinct IP- 151 enabled interfaces; at least one interface is operated in mode OCB of 152 IEEE 802.11 and is IP-enabled. An RSRU is similar to a Wireless 153 Termination Point (WTP), as defined in [RFC5415], or an Access Point 154 (AP), as defined in IEEE documents, or an Access Network Router (ANR) 155 defined in [RFC3753], with one key particularity: the wireless PHY/ 156 MAC layer of at least one of its IP-enabled interfaces is configured 157 to operate in 802.11-OCB mode. The RSRU communicates with the OBRU 158 in the vehicle over 802.11 wireless link operating in OCB mode. An 159 RSRU MAY be connected to the Internet, and MAY be an IP Router. When 160 it is connected to the Internet, the term V2I (Vehicle to Internet) 161 is relevant. 163 RSU (Road-Side Unit): an RSU operates in 802.11-OCB mode. A RSU 164 broadcasts data to OBUs or exchanges data with OBUs in its 165 communications zone. An RSU may provide channel assignments and 166 operating instructions to OBUs in its communications zone, when 167 required. The basic functional blocks of an RSU are: internal 168 computer processing, permanent storage capability, an integrated GPS 169 receiver for positioning and timing and an interface that supports 170 both IPv4 and IPv6 connectivity, compliant with 802.3at. An OCB 171 interface of an RSU MAY be IP-enabled simultaneously to being WAVE- 172 enabled or GeoNetworking-enabled (MAY support simultaneously 173 EtherTypes 0x86DD for IPv6 _and_ 0x88DC for WAVE and 0x8947 for 174 GeoNetworking). The difference between RSU and RSRU is that an RSU 175 is likely to have one single OCB interface which is likely not IP 176 enabled, whereas an RSRU is likely to have one or more OCB interfaces 177 which are almost always IP-enabled; moreover, an RSRU does IP 178 forwarding, whereas an RSU does not. 180 OCB (outside the context of a basic service set - BSS): A mode of 181 operation in which a STA is not a member of a BSS and does not 182 utilize IEEE Std 802.11 authentication, association, or data 183 confidentiality. 185 802.11-OCB: mode specified in IEEE Std 802.11-2016 when the MIB 186 attribute dot11OCBActivited is true. The OCB mode requires 187 transmission of QoS data frames (IEEE Std 802.11e), half-clocked 188 operation (IEEE Std 802.11j), and use of 5.9 GHz frequency band. 189 Nota: any implementation should comply with standards and regulations 190 set in the different countries for using that frequency band. 192 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 194 The IEEE 802.11-OCB Networks are used for vehicular communications, 195 as 'Wireless Access in Vehicular Environments'. The IP communication 196 scenarios for these environments have been described in several 197 documents; in particular, we refer the reader to 198 [I-D.ietf-ipwave-vehicular-networking-survey], that lists some 199 scenarios and requirements for IP in Intelligent Transportation 200 Systems. 202 The link model is the following: STA --- 802.11-OCB --- STA. In 203 vehicular networks, STAs can be RSRUs and/or OBRUs. While 802.11-OCB 204 is clearly specified, and the use of IPv6 over such link is not 205 radically new, the operating environment (vehicular networks) brings 206 in new perspectives. 208 The mechanisms for forming and terminating, discovering, peering and 209 mobility management for 802.11-OCB links are not described in this 210 document. 212 4. IPv6 over 802.11-OCB 214 4.1. Maximum Transmission Unit (MTU) 216 The default MTU for IP packets on 802.11-OCB is 1500 octets. It is 217 the same value as IPv6 packets on Ethernet links, as specified in 218 [RFC2464]. This value of the MTU respects the recommendation that 219 every link on the Internet must have a minimum MTU of 1280 octets 220 (stated in [RFC8200], and the recommendations therein, especially 221 with respect to fragmentation). If IPv6 packets of size larger than 222 1500 bytes are sent on an 802.11-OCB interface card then the IP stack 223 will fragment. In case there are IP fragments, the field "Sequence 224 number" of the 802.11 Data header containing the IP fragment field is 225 increased. 227 Non-IP packets such as WAVE Short Message Protocol (WSMP) can be 228 delivered on 802.11-OCB links. Specifications of these packets are 229 out of scope of this document, and do not impose any limit on the MTU 230 size, allowing an arbitrary number of 'containers'. Non-IP packets 231 such as ETSI GeoNetworking packets have an MTU of 1492 bytes. The 232 operation of IPv6 over GeoNetworking is specified at 233 [ETSI-IPv6-GeoNetworking]. 235 4.2. Frame Format 237 IP packets are transmitted over 802.11-OCB as standard Ethernet 238 packets. As with all 802.11 frames, an Ethernet adaptation layer is 239 used with 802.11-OCB as well. This Ethernet Adaptation Layer 240 performing 802.11-to-Ethernet is described in Section 4.2.1. The 241 Ethernet Type code (EtherType) for IPv6 is 0x86DD (hexadecimal 86DD, 242 or otherwise #86DD). 244 The Frame format for transmitting IPv6 on 802.11-OCB networks is the 245 same as transmitting IPv6 on Ethernet networks, and is described in 246 section 3 of [RFC2464]. 248 1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1 249 is the binary representation of the EtherType value 0x86DD. 251 4.2.1. Ethernet Adaptation Layer 253 An 'adaptation' layer is inserted between a MAC layer and the 254 Networking layer. This is used to transform some parameters between 255 their form expected by the IP stack and the form provided by the MAC 256 layer. 258 An Ethernet Adaptation Layer makes an 802.11 MAC look to IP 259 Networking layer as a more traditional Ethernet layer. At reception, 260 this layer takes as input the IEEE 802.11 Data Header and the 261 Logical-Link Layer Control Header and produces an Ethernet II Header. 262 At sending, the reverse operation is performed. 264 The operation of the Ethernet Adaptation Layer is depicted by the 265 double arrow in Figure 1. 267 +--------------------+------------+-------------+---------+-----------+ 268 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer| 269 +--------------------+------------+-------------+---------+-----------+ 270 \ / \ / 271 ----------------------------- -------- 272 \---------------------------------------------/ 273 ^ 274 | 275 802.11-to-Ethernet Adaptation Layer 276 | 277 v 278 +---------------------+-------------+---------+ 279 | Ethernet II Header | IPv6 Header | Payload | 280 +---------------------+-------------+---------+ 282 Figure 1: Operation of the Ethernet Adaptation Layer 284 The Receiver and Transmitter Address fields in the 802.11 Data Header 285 contain the same values as the Destination and the Source Address 286 fields in the Ethernet II Header, respectively. The value of the 287 Type field in the LLC Header is the same as the value of the Type 288 field in the Ethernet II Header. 290 The ".11 Trailer" contains solely a 4-byte Frame Check Sequence. 292 Additionally, the Ethernet Adaptation Layer performs operations in 293 relation to IP fragmentation and MTU. One of these operations is 294 briefly described in Section 4.1. 296 In OCB mode, IPv6 packets MAY be transmitted either as "IEEE 802.11 297 Data" or alternatively as "IEEE 802.11 QoS Data", as illustrated in 298 Figure 2. 300 +--------------------+-------------+-------------+---------+-----------+ 301 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer| 302 +--------------------+-------------+-------------+---------+-----------+ 304 or 306 +--------------------+-------------+-------------+---------+-----------+ 307 | 802.11 QoS Data Hdr| LLC Header | IPv6 Header | Payload |.11 Trailer| 308 +--------------------+-------------+-------------+---------+-----------+ 310 Figure 2: 802.11 Data Header or 802.11 QoS Data Header 312 The distinction between the two formats is given by the value of the 313 field "Type/Subtype". The value of the field "Type/Subtype" in the 314 802.11 Data header is 0x0020. The value of the field "Type/Subtype" 315 in the 802.11 QoS header is 0x0028. 317 The mapping between qos-related fields in the IPv6 header (e.g. 318 "Traffic Class", "Flow label") and fields in the "802.11 QoS Data 319 Header" (e.g. "QoS Control") are not specified in this document. 320 Guidance for a potential mapping is provided in 321 [I-D.ietf-tsvwg-ieee-802-11], although it is not specific to OCB 322 mode. 324 The placement of IPv6 networking layer on Ethernet Adaptation Layer 325 is illustrated in Figure 3. 327 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 328 | IPv6 | 329 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 330 | Ethernet Adaptation Layer | 331 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 332 | 802.11 WiFi MAC | 333 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 334 | 802.11 WiFi PHY | 335 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 337 Figure 3: Ethernet Adaptation Layer stacked with other layers 339 (in the above figure, a WiFi profile is represented; this is used 340 also for OCB profile.) 342 Other alternative views of layering are EtherType Protocol 343 Discrimination (EPD), see Appendix E, and SNAP see [RFC1042]. 345 4.3. Link-Local Addresses 347 The link-local address of an 802.11-OCB interface is formed in the 348 same manner as on an Ethernet interface. This manner is described in 349 section 5 of [RFC2464]. Additionally, if stable identifiers are 350 needed, it is recommended to follow the Recommendation on Stable IPv6 351 Interface Identifiers [RFC8064]. Additionally, if semantically 352 opaque Interface Identifiers are needed, a potential method for 353 generating semantically opaque Interface Identifiers with IPv6 354 Stateless Address Autoconfiguration is given in [RFC7217]. 356 4.4. Address Mapping 358 For unicast as for multicast, there is no change from the unicast and 359 multicast address mapping format of Ethernet interfaces, as defined 360 by sections 6 and 7 of [RFC2464]. 362 4.4.1. Address Mapping -- Unicast 364 The procedure for mapping IPv6 unicast addresses into Ethernet link- 365 layer addresses is described in [RFC4861]. 367 4.4.2. Address Mapping -- Multicast 369 The multicast address mapping is performed according to the method 370 specified in section 7 of [RFC2464]. The meaning of the value "3333" 371 mentioned in that section 7 of [RFC2464] is defined in section 2.3.1 372 of [RFC7042]. 374 Transmitting IPv6 packets to multicast destinations over 802.11 links 375 proved to have some performance issues 376 [I-D.perkins-intarea-multicast-ieee802]. These issues may be 377 exacerbated in OCB mode. Solutions for these problems should 378 consider the OCB mode of operation. 380 4.5. Stateless Autoconfiguration 382 The Interface Identifier for an 802.11-OCB interface is formed using 383 the same rules as the Interface Identifier for an Ethernet interface; 384 this is described in section 4 of [RFC2464]. No changes are needed, 385 but some care must be taken when considering the use of the Stateless 386 Address Auto-Configuration procedure. 388 The bits in the interface identifier have no generic meaning and the 389 identifier should be treated as an opaque value. The bits 390 'Universal' and 'Group' in the identifier of an 802.11-OCB interface 391 are significant, as this is an IEEE link-layer address. The details 392 of this significance are described in [RFC7136]. 394 As with all Ethernet and 802.11 interface identifiers ([RFC7721]), 395 the identifier of an 802.11-OCB interface may involve privacy, MAC 396 address spoofing and IP address hijacking risks. A vehicle embarking 397 an OBU or an OBRU whose egress interface is 802.11-OCB may expose 398 itself to eavesdropping and subsequent correlation of data; this may 399 reveal data considered private by the vehicle owner; there is a risk 400 of being tracked; see the privacy considerations described in 401 Appendix F. 403 If stable Interface Identifiers are needed in order to form IPv6 404 addresses on 802.11-OCB links, it is recommended to follow the 405 recommendation in [RFC8064]. Additionally, if semantically opaque 406 Interface Identifiers are needed, a potential method for generating 407 semantically opaque Interface Identifiers with IPv6 Stateless Address 408 Autoconfiguration is given in [RFC7217]. 410 4.6. Subnet Structure 412 A subnet is formed by the external 802.11-OCB interfaces of vehicles 413 that are in close range (not their on-board interfaces). This 414 ephemeral subnet structure is strongly influenced by the mobility of 415 vehicles: the 802.11 hidden node effects appear. On another hand, 416 the structure of the internal subnets in each car is relatively 417 stable. 419 The 802.11 networks in OCB mode may be considered as 'ad-hoc' 420 networks. The addressing model for such networks is described in 421 [RFC5889]. 423 An addressing model involves several types of addresses, like 424 Globally-unique Addresses (GUA), Link-Local Addresses (LL) and Unique 425 Local Addresses (ULA). The subnet structure in 'ad-hoc' networks may 426 have characteristics that lead to difficulty of using GUAs derived 427 from a received prefix, but the LL addresses may be easier to use 428 since the prefix is constant. 430 5. Security Considerations 432 Any security mechanism at the IP layer or above that may be carried 433 out for the general case of IPv6 may also be carried out for IPv6 434 operating over 802.11-OCB. 436 The OCB operation is stripped off of all existing 802.11 link-layer 437 security mechanisms. There is no encryption applied below the 438 network layer running on 802.11-OCB. At application layer, the IEEE 439 1609.2 document [IEEE-1609.2] does provide security services for 440 certain applications to use; application-layer mechanisms are out-of- 441 scope of this document. On another hand, a security mechanism 442 provided at networking layer, such as IPsec [RFC4301], may provide 443 data security protection to a wider range of applications. 445 802.11-OCB does not provide any cryptographic protection, because it 446 operates outside the context of a BSS (no Association Request/ 447 Response, no Challenge messages). Any attacker can therefore just 448 sit in the near range of vehicles, sniff the network (just set the 449 interface card's frequency to the proper range) and perform attacks 450 without needing to physically break any wall. Such a link is less 451 protected than commonly used links (wired link or protected 802.11). 453 The potential attack vectors are: MAC address spoofing, IP address 454 and session hijacking and privacy violation. 456 Within the IPsec Security Architecture [RFC4301], the IPsec AH and 457 ESP headers [RFC4302] and [RFC4303] respectively, its multicast 458 extensions [RFC5374], HTTPS [RFC2818] and SeND [RFC3971] protocols 459 can be used to protect communications. Further, the assistance of 460 proper Public Key Infrastructure (PKI) protocols [RFC4210] is 461 necessary to establish credentials. More IETF protocols are 462 available in the toolbox of the IP security protocol designer. 463 Certain ETSI protocols related to security protocols in Intelligent 464 Transportation Systems are described in [ETSI-sec-archi]. 466 As with all Ethernet and 802.11 interface identifiers, there may 467 exist privacy risks in the use of 802.11-OCB interface identifiers. 468 Moreover, in outdoors vehicular settings, the privacy risks are more 469 important than in indoors settings. New risks are induced by the 470 possibility of attacker sniffers deployed along routes which listen 471 for IP packets of vehicles passing by. For this reason, in the 472 802.11-OCB deployments, there is a strong necessity to use protection 473 tools such as dynamically changing MAC addresses. This may help 474 mitigate privacy risks to a certain level. On another hand, it may 475 have an impact in the way typical IPv6 address auto-configuration is 476 performed for vehicles (SLAAC would rely on MAC addresses amd would 477 hence dynamically change the affected IP address), in the way the 478 IPv6 Privacy addresses were used, and other effects. 480 6. IANA Considerations 482 No request to IANA. 484 7. Contributors 486 Christian Huitema, Tony Li. 488 Romain Kuntz contributed extensively about IPv6 handovers between 489 links running outside the context of a BSS (802.11-OCB links). 491 Tim Leinmueller contributed the idea of the use of IPv6 over 492 802.11-OCB for distribution of certificates. 494 Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey 495 Voronov provided significant feedback on the experience of using IP 496 messages over 802.11-OCB in initial trials. 498 Michelle Wetterwald contributed extensively the MTU discussion, 499 offered the ETSI ITS perspective, and reviewed other parts of the 500 document. 502 8. Acknowledgements 504 The authors would like to thank Witold Klaudel, Ryuji Wakikawa, 505 Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan 506 Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray 507 Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, 508 Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne, 509 Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark, 510 Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley, Sandra 511 Cespedes, Mariano Falcitelli, Sri Gundavelli, Abdussalam Baryun, 512 Margaret Cullen and William Whyte. Their valuable comments clarified 513 particular issues and generally helped to improve the document. 515 Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB 516 drivers for linux and described how. 518 For the multicast discussion, the authors would like to thank Owen 519 DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and 520 participants to discussions in network working groups. 522 The authors would like to thank participants to the Birds-of- 523 a-Feather "Intelligent Transportation Systems" meetings held at IETF 524 in 2016. 526 9. References 528 9.1. Normative References 530 [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission 531 of IP datagrams over IEEE 802 networks", STD 43, RFC 1042, 532 DOI 10.17487/RFC1042, February 1988, 533 . 535 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 536 Requirement Levels", BCP 14, RFC 2119, 537 DOI 10.17487/RFC2119, March 1997, 538 . 540 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 541 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 542 . 544 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 545 DOI 10.17487/RFC2818, May 2000, 546 . 548 [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related 549 Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, 550 . 552 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 553 "SEcure Neighbor Discovery (SEND)", RFC 3971, 554 DOI 10.17487/RFC3971, March 2005, 555 . 557 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 558 "Randomness Requirements for Security", BCP 106, RFC 4086, 559 DOI 10.17487/RFC4086, June 2005, 560 . 562 [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, 563 "Internet X.509 Public Key Infrastructure Certificate 564 Management Protocol (CMP)", RFC 4210, 565 DOI 10.17487/RFC4210, September 2005, 566 . 568 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 569 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 570 December 2005, . 572 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 573 DOI 10.17487/RFC4302, December 2005, 574 . 576 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 577 RFC 4303, DOI 10.17487/RFC4303, December 2005, 578 . 580 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 581 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 582 DOI 10.17487/RFC4861, September 2007, 583 . 585 [RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast 586 Extensions to the Security Architecture for the Internet 587 Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008, 588 . 590 [RFC5415] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, 591 Ed., "Control And Provisioning of Wireless Access Points 592 (CAPWAP) Protocol Specification", RFC 5415, 593 DOI 10.17487/RFC5415, March 2009, 594 . 596 [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing 597 Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889, 598 September 2010, . 600 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 601 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 602 2011, . 604 [RFC7042] Eastlake 3rd, D. and J. Abley, "IANA Considerations and 605 IETF Protocol and Documentation Usage for IEEE 802 606 Parameters", BCP 141, RFC 7042, DOI 10.17487/RFC7042, 607 October 2013, . 609 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 610 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 611 February 2014, . 613 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 614 Interface Identifiers with IPv6 Stateless Address 615 Autoconfiguration (SLAAC)", RFC 7217, 616 DOI 10.17487/RFC7217, April 2014, 617 . 619 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 620 Considerations for IPv6 Address Generation Mechanisms", 621 RFC 7721, DOI 10.17487/RFC7721, March 2016, 622 . 624 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 625 "Recommendation on Stable IPv6 Interface Identifiers", 626 RFC 8064, DOI 10.17487/RFC8064, February 2017, 627 . 629 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 630 (IPv6) Specification", STD 86, RFC 8200, 631 DOI 10.17487/RFC8200, July 2017, 632 . 634 9.2. Informative References 636 [ETSI-IPv6-GeoNetworking] 637 "ETSI EN 302 636-6-1 v1.2.1 (2014-05), ETSI, European 638 Standard, Intelligent Transportation Systems (ITS); 639 Vehicular Communications; Geonetworking; Part 6: Internet 640 Integration; Sub-part 1: Transmission of IPv6 Packets over 641 Geonetworking Protocols. Downloaded on September 9th, 642 2017, freely available from ETSI website at URL 643 http://www.etsi.org/deliver/ 644 etsi_en/302600_302699/30263601/01.02.01_60/ 645 en_30263601v010201p.pdf". 647 [ETSI-sec-archi] 648 "ETSI TS 102 940 V1.2.1 (2016-11), ETSI Technical 649 Specification, Intelligent Transport Systems (ITS); 650 Security; ITS communications security architecture and 651 security management, November 2016. Downloaded on 652 September 9th, 2017, freely available from ETSI website at 653 URL http://www.etsi.org/deliver/ 654 etsi_ts/102900_102999/102940/01.02.01_60/ 655 ts_102940v010201p.pdf". 657 [I-D.hinden-6man-rfc2464bis] 658 Crawford, M. and R. Hinden, "Transmission of IPv6 Packets 659 over Ethernet Networks", draft-hinden-6man-rfc2464bis-02 660 (work in progress), March 2017. 662 [I-D.ietf-ipwave-vehicular-networking-survey] 663 Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M. 664 Wetterwald, "Survey on IP-based Vehicular Networking for 665 Intelligent Transportation Systems", draft-ietf-ipwave- 666 vehicular-networking-survey-00 (work in progress), July 667 2017. 669 [I-D.ietf-tsvwg-ieee-802-11] 670 Szigeti, T., Henry, J., and F. Baker, "Diffserv to IEEE 671 802.11 Mapping", draft-ietf-tsvwg-ieee-802-11-09 (work in 672 progress), September 2017. 674 [I-D.perkins-intarea-multicast-ieee802] 675 Perkins, C., Stanley, D., Kumari, W., and J. Zuniga, 676 "Multicast Considerations over IEEE 802 Wireless Media", 677 draft-perkins-intarea-multicast-ieee802-03 (work in 678 progress), July 2017. 680 [IEEE-1609.2] 681 "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access 682 in Vehicular Environments (WAVE) -- Security Services for 683 Applications and Management Messages. Example URL 684 http://ieeexplore.ieee.org/document/7426684/ accessed on 685 August 17th, 2017.". 687 [IEEE-1609.3] 688 "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access 689 in Vehicular Environments (WAVE) -- Networking Services. 690 Example URL http://ieeexplore.ieee.org/document/7458115/ 691 accessed on August 17th, 2017.". 693 [IEEE-1609.4] 694 "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access 695 in Vehicular Environments (WAVE) -- Multi-Channel 696 Operation. Example URL 697 http://ieeexplore.ieee.org/document/7435228/ accessed on 698 August 17th, 2017.". 700 [IEEE-802.11-2016] 701 "IEEE Standard 802.11-2016 - IEEE Standard for Information 702 Technology - Telecommunications and information exchange 703 between systems Local and metropolitan area networks - 704 Specific requirements - Part 11: Wireless LAN Medium 705 Access Control (MAC) and Physical Layer (PHY) 706 Specifications. Status - Active Standard. Description 707 retrieved freely on September 12th, 2017, at URL 708 https://standards.ieee.org/findstds/ 709 standard/802.11-2016.html". 711 [IEEE-802.11p-2010] 712 "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information 713 Technology - Telecommunications and information exchange 714 between systems - Local and metropolitan area networks - 715 Specific requirements, Part 11: Wireless LAN Medium Access 716 Control (MAC) and Physical Layer (PHY) Specifications, 717 Amendment 6: Wireless Access in Vehicular Environments; 718 document freely available at URL 719 http://standards.ieee.org/getieee802/ 720 download/802.11p-2010.pdf retrieved on September 20th, 721 2013.". 723 Appendix A. ChangeLog 725 The changes are listed in reverse chronological order, most recent 726 changes appearing at the top of the list. 728 From draft-ietf-ipwave-ipv6-over-80211ocb-10 to draft-ietf-ipwave- 729 ipv6-over-80211ocb-11 731 o Shortened the paragraph on forming/terminating 802.11-OCB links. 733 o Moved the draft tsvwg-ieee-802-11 to Informative References. 735 From draft-ietf-ipwave-ipv6-over-80211ocb-09 to draft-ietf-ipwave- 736 ipv6-over-80211ocb-10 738 o Removed text requesting a new Group ID for multicast for OCB. 740 o Added a clarification of the meaning of value "3333" in the 741 section Address Mapping -- Multicast. 743 o Added note clarifying that in Europe the regional authority is not 744 ETSI, but "ECC/CEPT based on ENs from ETSI". 746 o Added note stating that the manner in which two STAtions set their 747 communication channel is not described in this document. 749 o Added a time qualifier to state that the "each node is represented 750 uniquely at a certain point in time." 752 o Removed text "This section may need to be moved" (the "Reliability 753 Requirements" section). This section stays there at this time. 755 o In the term definition "802.11-OCB" added a note stating that "any 756 implementation should comply with standards and regulations set in 757 the different countries for using that frequency band." 759 o In the RSU term definition, added a sentence explaining the 760 difference between RSU and RSRU: in terms of number of interfaces 761 and IP forwarding. 763 o Replaced "with at least two IP interfaces" with "with at least two 764 real or virtual IP interfaces". 766 o Added a term in the Terminology for "OBU". However the definition 767 is left empty, as this term is defined outside IETF. 769 o Added a clarification that it is an OBU or an OBRU in this phrase 770 "A vehicle embarking an OBU or an OBRU". 772 o Checked the entire document for a consistent use of terms OBU and 773 OBRU. 775 o Added note saying that "'p' is a letter identifying the 776 Ammendment". 778 o Substituted lower case for capitals SHALL or MUST in the 779 Appendices. 781 o Added reference to RFC7042, helpful in the 3333 explanation. 782 Removed reference to individual submission draft-petrescu-its- 783 scenario-reqs and added reference to draft-ietf-ipwave-vehicular- 784 networking-survey. 786 o Added figure captions, figure numbers, and references to figure 787 numbers instead of 'below'. Replaced "section Section" with 788 "section" throughout. 790 o Minor typographical errors. 792 From draft-ietf-ipwave-ipv6-over-80211ocb-08 to draft-ietf-ipwave- 793 ipv6-over-80211ocb-09 795 o Significantly shortened the Address Mapping sections, by text 796 copied from RFC2464, and rather referring to it. 798 o Moved the EPD description to an Appendix on its own. 800 o Shortened the Introduction and the Abstract. 802 o Moved the tutorial section of OCB mode introduced to .11, into an 803 appendix. 805 o Removed the statement that suggests that for routing purposes a 806 prefix exchange mechanism could be needed. 808 o Removed refs to RFC3963, RFC4429 and RFC6775; these are about ND, 809 MIP/NEMO and oDAD; they were referred in the handover discussion 810 section, which is out. 812 o Updated a reference from individual submission to now a WG item in 813 IPWAVE: the survey document. 815 o Added term definition for WiFi. 817 o Updated the authorship and expanded the Contributors section. 819 o Corrected typographical errors. 821 From draft-ietf-ipwave-ipv6-over-80211ocb-07 to draft-ietf-ipwave- 822 ipv6-over-80211ocb-08 824 o Removed the per-channel IPv6 prohibition text. 826 o Corrected typographical errors. 828 From draft-ietf-ipwave-ipv6-over-80211ocb-06 to draft-ietf-ipwave- 829 ipv6-over-80211ocb-07 831 o Added new terms: OBRU and RSRU ('R' for Router). Refined the 832 existing terms RSU and OBU, which are no longer used throughout 833 the document. 835 o Improved definition of term "802.11-OCB". 837 o Clarified that OCB does not "strip" security, but that the 838 operation in OCB mode is "stripped off of all .11 security". 840 o Clarified that theoretical OCB bandwidth speed is 54mbits, but 841 that a commonly observed bandwidth in IP-over-OCB is 12mbit/s. 843 o Corrected typographical errors, and improved some phrasing. 845 From draft-ietf-ipwave-ipv6-over-80211ocb-05 to draft-ietf-ipwave- 846 ipv6-over-80211ocb-06 848 o Updated references of 802.11-OCB document from -2012 to the IEEE 849 802.11-2016. 851 o In the LL address section, and in SLAAC section, added references 852 to 7217 opaque IIDs and 8064 stable IIDs. 854 From draft-ietf-ipwave-ipv6-over-80211ocb-04 to draft-ietf-ipwave- 855 ipv6-over-80211ocb-05 857 o Lengthened the title and cleanded the abstract. 859 o Added text suggesting LLs may be easy to use on OCB, rather than 860 GUAs based on received prefix. 862 o Added the risks of spoofing and hijacking. 864 o Removed the text speculation on adoption of the TSA message. 866 o Clarified that the ND protocol is used. 868 o Clarified what it means "No association needed". 870 o Added some text about how two STAs discover each other. 872 o Added mention of external (OCB) and internal network (stable), in 873 the subnet structure section. 875 o Added phrase explaining that both .11 Data and .11 QoS Data 876 headers are currently being used, and may be used in the future. 878 o Moved the packet capture example into an Appendix Implementation 879 Status. 881 o Suggested moving the reliability requirements appendix out into 882 another document. 884 o Added a IANA Consiserations section, with content, requesting for 885 a new multicast group "all OCB interfaces". 887 o Added new OBU term, improved the RSU term definition, removed the 888 ETTC term, replaced more occurences of 802.11p, 802.11 OCB with 889 802.11-OCB. 891 o References: 893 * Added an informational reference to ETSI's IPv6-over- 894 GeoNetworking. 896 * Added more references to IETF and ETSI security protocols. 898 * Updated some references from I-D to RFC, and from old RFC to 899 new RFC numbers. 901 * Added reference to multicast extensions to IPsec architecture 902 RFC. 904 * Added a reference to 2464-bis. 906 * Removed FCC informative references, because not used. 908 o Updated the affiliation of one author. 910 o Reformulation of some phrases for better readability, and 911 correction of typographical errors. 913 From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave- 914 ipv6-over-80211ocb-04 916 o Removed a few informative references pointing to Dx draft IEEE 917 1609 documents. 919 o Removed outdated informative references to ETSI documents. 921 o Added citations to IEEE 1609.2, .3 and .4-2016. 923 o Minor textual issues. 925 From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave- 926 ipv6-over-80211ocb-03 928 o Keep the previous text on multiple addresses, so remove talk about 929 MIP6, NEMOv6 and MCoA. 931 o Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon. 933 o Clarified the figure showing Infrastructure mode and OCB mode side 934 by side. 936 o Added a reference to the IP Security Architecture RFC. 938 o Detailed the IPv6-per-channel prohibition paragraph which reflects 939 the discussion at the last IETF IPWAVE WG meeting. 941 o Added section "Address Mapping -- Unicast". 943 o Added the ".11 Trailer" to pictures of 802.11 frames. 945 o Added text about SNAP carrying the Ethertype. 947 o New RSU definition allowing for it be both a Router and not 948 necessarily a Router some times. 950 o Minor textual issues. 952 From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave- 953 ipv6-over-80211ocb-02 955 o Replaced almost all occurences of 802.11p with 802.11-OCB, leaving 956 only when explanation of evolution was necessary. 958 o Shortened by removing parameter details from a paragraph in the 959 Introduction. 961 o Moved a reference from Normative to Informative. 963 o Added text in intro clarifying there is no handover spec at IEEE, 964 and that 1609.2 does provide security services. 966 o Named the contents the fields of the EthernetII header (including 967 the Ethertype bitstring). 969 o Improved relationship between two paragraphs describing the 970 increase of the Sequence Number in 802.11 header upon IP 971 fragmentation. 973 o Added brief clarification of "tracking". 975 From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave- 976 ipv6-over-80211ocb-01 978 o Introduced message exchange diagram illustrating differences 979 between 802.11 and 802.11 in OCB mode. 981 o Introduced an appendix listing for information the set of 802.11 982 messages that may be transmitted in OCB mode. 984 o Removed appendix sections "Privacy Requirements", "Authentication 985 Requirements" and "Security Certificate Generation". 987 o Removed appendix section "Non IP Communications". 989 o Introductory phrase in the Security Considerations section. 991 o Improved the definition of "OCB". 993 o Introduced theoretical stacked layers about IPv6 and IEEE layers 994 including EPD. 996 o Removed the appendix describing the details of prohibiting IPv6 on 997 certain channels relevant to 802.11-OCB. 999 o Added a brief reference in the privacy text about a precise clause 1000 in IEEE 1609.3 and .4. 1002 o Clarified the definition of a Road Side Unit. 1004 o Removed the discussion about security of WSA (because is non-IP). 1006 o Removed mentioning of the GeoNetworking discussion. 1008 o Moved references to scientific articles to a separate 'overview' 1009 draft, and referred to it. 1011 Appendix B. 802.11p 1013 The term "802.11p" is an earlier definition. The behaviour of 1014 "802.11p" networks is rolled in the document IEEE Std 802.11-2016. 1015 In that document the term 802.11p disappears. Instead, each 802.11p 1016 feature is conditioned by the Management Information Base (MIB) 1017 attribute "OCBActivated". Whenever OCBActivated is set to true the 1018 IEEE Std 802.11 OCB state is activated. For example, an 802.11 1019 STAtion operating outside the context of a basic service set has the 1020 OCBActivated flag set. Such a station, when it has the flag set, 1021 uses a BSS identifier equal to ff:ff:ff:ff:ff:ff. 1023 Appendix C. Aspects introduced by the OCB mode to 802.11 1025 In the IEEE 802.11-OCB mode, all nodes in the wireless range can 1026 directly communicate with each other without involving authentication 1027 or association procedures. At link layer, it is necessary to set the 1028 same channel number (or frequency) on two stations that need to 1029 communicate with each other. The manner in which stations set their 1030 channel number is not specified in this document. Stations STA1 and 1031 STA2 can exchange IP packets if they are set on the same channel. At 1032 IP layer, they then discover each other by using the IPv6 Neighbor 1033 Discovery protocol. 1035 Briefly, the IEEE 802.11-OCB mode has the following properties: 1037 o The use by each node of a 'wildcard' BSSID (i.e., each bit of the 1038 BSSID is set to 1) 1040 o No IEEE 802.11 Beacon frames are transmitted 1042 o No authentication is required in order to be able to communicate 1044 o No association is needed in order to be able to communicate 1046 o No encryption is provided in order to be able to communicate 1048 o Flag dot11OCBActivated is set to true 1050 All the nodes in the radio communication range (OBRU and RSRU) 1051 receive all the messages transmitted (OBRU and RSRU) within the radio 1052 communications range. The eventual conflict(s) are resolved by the 1053 MAC CDMA function. 1055 The message exchange diagram in Figure 4 illustrates a comparison 1056 between traditional 802.11 and 802.11 in OCB mode. The 'Data' 1057 messages can be IP packets such as HTTP or others. Other 802.11 1058 management and control frames (non IP) may be transmitted, as 1059 specified in the 802.11 standard. For information, the names of 1060 these messages as currently specified by the 802.11 standard are 1061 listed in Appendix G. 1063 STA AP STA1 STA2 1064 | | | | 1065 |<------ Beacon -------| |<------ Data -------->| 1066 | | | | 1067 |---- Probe Req. ----->| |<------ Data -------->| 1068 |<--- Probe Res. ------| | | 1069 | | |<------ Data -------->| 1070 |---- Auth Req. ------>| | | 1071 |<--- Auth Res. -------| |<------ Data -------->| 1072 | | | | 1073 |---- Asso Req. ------>| |<------ Data -------->| 1074 |<--- Asso Res. -------| | | 1075 | | |<------ Data -------->| 1076 |<------ Data -------->| | | 1077 |<------ Data -------->| |<------ Data -------->| 1079 (i) 802.11 Infrastructure mode (ii) 802.11-OCB mode 1081 Figure 4: Difference between messages exchanged on 802.11 (left) and 1082 802.11-OCB (right) 1084 The interface 802.11-OCB was specified in IEEE Std 802.11p (TM) -2010 1085 [IEEE-802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, 1086 titled "Amendment 6: Wireless Access in Vehicular Environments". 1087 Since then, this amendment has been integrated in IEEE 802.11(TM) 1088 -2012 and -2016 [IEEE-802.11-2016]. 1090 In document 802.11-2016, anything qualified specifically as 1091 "OCBActivated", or "outside the context of a basic service" set to be 1092 true, then it is actually referring to OCB aspects introduced to 1093 802.11. 1095 In order to delineate the aspects introduced by 802.11-OCB to 802.11, 1096 we refer to the earlier [IEEE-802.11p-2010]. The amendment is 1097 concerned with vehicular communications, where the wireless link is 1098 similar to that of Wireless LAN (using a PHY layer specified by 1099 802.11a/b/g/n), but which needs to cope with the high mobility factor 1100 inherent in scenarios of communications between moving vehicles, and 1101 between vehicles and fixed infrastructure deployed along roads. 1102 While 'p' is a letter identifying the Ammendment, just like 'a, b, g' 1103 and 'n' are, 'p' is concerned more with MAC modifications, and a 1104 little with PHY modifications; the others are mainly about PHY 1105 modifications. It is possible in practice to combine a 'p' MAC with 1106 an 'a' PHY by operating outside the context of a BSS with OFDM at 1107 5.4GHz and 5.9GHz. 1109 The 802.11-OCB links are specified to be compatible as much as 1110 possible with the behaviour of 802.11a/b/g/n and future generation 1111 IEEE WLAN links. From the IP perspective, an 802.11-OCB MAC layer 1112 offers practically the same interface to IP as the WiFi and Ethernet 1113 layers do (802.11a/b/g/n and 802.3). A packet sent by an OBRU may be 1114 received by one or multiple RSRUs. The link-layer resolution is 1115 performed by using the IPv6 Neighbor Discovery protocol. 1117 To support this similarity statement (IPv6 is layered on top of LLC 1118 on top of 802.11-OCB, in the same way that IPv6 is layered on top of 1119 LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on 1120 top of 802.3 (for Ethernet)) it is useful to analyze the differences 1121 between 802.11-OCB and 802.11 specifications. During this analysis, 1122 we note that whereas 802.11-OCB lists relatively complex and numerous 1123 changes to the MAC layer (and very little to the PHY layer), there 1124 are only a few characteristics which may be important for an 1125 implementation transmitting IPv6 packets on 802.11-OCB links. 1127 The most important 802.11-OCB point which influences the IPv6 1128 functioning is the OCB characteristic; an additional, less direct 1129 influence, is the maximum bandwidth afforded by the PHY modulation/ 1130 demodulation methods and channel access specified by 802.11-OCB. The 1131 maximum bandwidth theoretically possible in 802.11-OCB is 54 Mbit/s 1132 (when using, for example, the following parameters: 20 MHz channel; 1133 modulation 64-QAM; coding rate R is 3/4); in practice of IP-over- 1134 802.11-OCB a commonly observed figure is 12Mbit/s; this bandwidth 1135 allows the operation of a wide range of protocols relying on IPv6. 1137 o Operation Outside the Context of a BSS (OCB): the (earlier 1138 802.11p) 802.11-OCB links are operated without a Basic Service Set 1139 (BSS). This means that the frames IEEE 802.11 Beacon, Association 1140 Request/Response, Authentication Request/Response, and similar, 1141 are not used. The used identifier of BSS (BSSID) has a 1142 hexadecimal value always 0xffffffffffff (48 '1' bits, represented 1143 as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' 1144 BSSID), as opposed to an arbitrary BSSID value set by 1145 administrator (e.g. 'My-Home-AccessPoint'). The OCB operation - 1146 namely the lack of beacon-based scanning and lack of 1147 authentication - should be taken into account when the Mobile IPv6 1148 protocol [RFC6275] and the protocols for IP layer security 1149 [RFC4301] are used. The way these protocols adapt to OCB is not 1150 described in this document. 1152 o Timing Advertisement: is a new message defined in 802.11-OCB, 1153 which does not exist in 802.11a/b/g/n. This message is used by 1154 stations to inform other stations about the value of time. It is 1155 similar to the time as delivered by a GNSS system (Galileo, GPS, 1156 ...) or by a cellular system. This message is optional for 1157 implementation. 1159 o Frequency range: this is a characteristic of the PHY layer, with 1160 almost no impact on the interface between MAC and IP. However, it 1161 is worth considering that the frequency range is regulated by a 1162 regional authority (ARCEP, ECC/CEPT based on ENs from ETSI, FCC, 1163 etc.); as part of the regulation process, specific applications 1164 are associated with specific frequency ranges. In the case of 1165 802.11-OCB, the regulator associates a set of frequency ranges, or 1166 slots within a band, to the use of applications of vehicular 1167 communications, in a band known as "5.9GHz". The 5.9GHz band is 1168 different from the 2.4GHz and 5GHz bands used by Wireless LAN. 1169 However, as with Wireless LAN, the operation of 802.11-OCB in 1170 "5.9GHz" bands is exempt from owning a license in EU (in US the 1171 5.9GHz is a licensed band of spectrum; for the fixed 1172 infrastructure an explicit FCC authorization is required; for an 1173 on-board device a 'licensed-by-rule' concept applies: rule 1174 certification conformity is required.) Technical conditions are 1175 different than those of the bands "2.4GHz" or "5GHz". The allowed 1176 power levels, and implicitly the maximum allowed distance between 1177 vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20 1178 dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum 1179 distance of approximately 1km, compared to approximately 50m. 1181 Additionally, specific conditions related to congestion avoidance, 1182 jamming avoidance, and radar detection are imposed on the use of 1183 DSRC (in US) and on the use of frequencies for Intelligent 1184 Transportation Systems (in EU), compared to Wireless LAN 1185 (802.11a/b/g/n). 1187 o 'Half-rate' encoding: as the frequency range, this parameter is 1188 related to PHY, and thus has not much impact on the interface 1189 between the IP layer and the MAC layer. 1191 o In vehicular communications using 802.11-OCB links, there are 1192 strong privacy requirements with respect to addressing. While the 1193 802.11-OCB standard does not specify anything in particular with 1194 respect to MAC addresses, in these settings there exists a strong 1195 need for dynamic change of these addresses (as opposed to the non- 1196 vehicular settings - real wall protection - where fixed MAC 1197 addresses do not currently pose some privacy risks). This is 1198 further described in Section 5. A relevant function is described 1199 in IEEE 1609.3-2016 [IEEE-1609.3], clause 5.5.1 and IEEE 1200 1609.4-2016 [IEEE-1609.4], clause 6.7. 1202 Other aspects particular to 802.11-OCB, which are also particular to 1203 802.11 (e.g. the 'hidden node' operation), may have an influence on 1204 the use of transmission of IPv6 packets on 802.11-OCB networks. The 1205 OCB subnet structure is described in Section 4.6. 1207 Appendix D. Changes Needed on a software driver 802.11a to become a 1208 802.11-OCB driver 1210 The 802.11p amendment modifies both the 802.11 stack's physical and 1211 MAC layers but all the induced modifications can be quite easily 1212 obtained by modifying an existing 802.11a ad-hoc stack. 1214 Conditions for a 802.11a hardware to be 802.11-OCB compliant: 1216 o The PHY entity shall be an orthogonal frequency division 1217 multiplexing (OFDM) system. It must support the frequency bands 1218 on which the regulator recommends the use of ITS communications, 1219 for example using IEEE 802.11-OCB layer, in France: 5875MHz to 1220 5925MHz. 1222 o The OFDM system must provide a "half-clocked" operation using 10 1223 MHz channel spacings. 1225 o The chip transmit spectrum mask must be compliant to the "Transmit 1226 spectrum mask" from the IEEE 802.11p amendment (but experimental 1227 environments tolerate otherwise). 1229 o The chip should be able to transmit up to 44.8 dBm when used by 1230 the US government in the United States, and up to 33 dBm in 1231 Europe; other regional conditions apply. 1233 Changes needed on the network stack in OCB mode: 1235 o Physical layer: 1237 * The chip must use the Orthogonal Frequency Multiple Access 1238 (OFDM) encoding mode. 1240 * The chip must be set in half-mode rate mode (the internal clock 1241 frequency is divided by two). 1243 * The chip must use dedicated channels and should allow the use 1244 of higher emission powers. This may require modifications to 1245 the local computer file that describes regulatory domains 1246 rules, if used by the kernel to enforce local specific 1247 restrictions. Such modifications to the local computer file 1248 must respect the location-specific regulatory rules. 1250 MAC layer: 1252 * All management frames (beacons, join, leave, and others) 1253 emission and reception must be disabled except for frames of 1254 subtype Action and Timing Advertisement (defined below). 1256 * No encryption key or method must be used. 1258 * Packet emission and reception must be performed as in ad-hoc 1259 mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff). 1261 * The functions related to joining a BSS (Association Request/ 1262 Response) and for authentication (Authentication Request/Reply, 1263 Challenge) are not called. 1265 * The beacon interval is always set to 0 (zero). 1267 * Timing Advertisement frames, defined in the amendment, should 1268 be supported. The upper layer should be able to trigger such 1269 frames emission and to retrieve information contained in 1270 received Timing Advertisements. 1272 Appendix E. EtherType Protocol Discrimination (EPD) 1274 A more theoretical and detailed view of layer stacking, and 1275 interfaces between the IP layer and 802.11-OCB layers, is illustrated 1276 in Figure 5. The IP layer operates on top of the EtherType Protocol 1277 Discrimination (EPD); this Discrimination layer is described in IEEE 1278 Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP 1279 (Link Layer Control Service Access Point). 1281 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1282 | IPv6 | 1283 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ 1284 { LLC_SAP } 802.11-OCB 1285 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary 1286 | EPD | | | 1287 | | MLME | | 1288 +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | 1289 | MAC Sublayer | | | 802.11-OCB 1290 | and ch. coord. | | SME | Services 1291 +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | 1292 | | PLME | | 1293 | PHY Layer | PLME_SAP | 1294 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1296 Figure 5: EtherType Protocol Discrimination 1298 Appendix F. Design Considerations 1300 The networks defined by 802.11-OCB are in many ways similar to other 1301 networks of the 802.11 family. In theory, the encapsulation of IPv6 1302 over 802.11-OCB could be very similar to the operation of IPv6 over 1303 other networks of the 802.11 family. However, the high mobility, 1304 strong link asymmetry and very short connection makes the 802.11-OCB 1305 link significantly different from other 802.11 networks. Also, the 1306 automotive applications have specific requirements for reliability, 1307 security and privacy, which further add to the particularity of the 1308 802.11-OCB link. 1310 F.1. Vehicle ID 1312 In automotive networks it is required that each node is represented 1313 uniquely at a certain point in time. Accordingly, a vehicle must be 1314 identified by at least one unique identifier. The current 1315 specification at ETSI and at IEEE 1609 identifies a vehicle by its 1316 MAC address, which is obtained from the 802.11-OCB Network Interface 1317 Card (NIC). 1319 In case multiple 802.11-OCB NICs are present in one car, implicitely 1320 multiple vehicle IDs will be generated. Additionally, some software 1321 generates a random MAC address each time the computer boots; this 1322 constitutes an additional difficulty. 1324 A mechanim to uniquely identify a vehicle irrespectively to the 1325 multiplicity of NICs, or frequent MAC address generation, is 1326 necessary. 1328 F.2. Reliability Requirements 1330 The dynamically changing topology, short connectivity, mobile 1331 transmitter and receivers, different antenna heights, and many-to- 1332 many communication types, make IEEE 802.11-OCB links significantly 1333 different from other IEEE 802.11 links. Any IPv6 mechanism operating 1334 on IEEE 802.11-OCB link must support strong link asymmetry, spatio- 1335 temporal link quality, fast address resolution and transmission. 1337 IEEE 802.11-OCB strongly differs from other 802.11 systems to operate 1338 outside of the context of a Basic Service Set. This means in 1339 practice that IEEE 802.11-OCB does not rely on a Base Station for all 1340 Basic Service Set management. In particular, IEEE 802.11-OCB shall 1341 not use beacons. Any IPv6 mechanism requiring L2 services from IEEE 1342 802.11 beacons must support an alternative service. 1344 Channel scanning being disabled, IPv6 over IEEE 802.11-OCB must 1345 implement a mechanism for transmitter and receiver to converge to a 1346 common channel. 1348 Authentication not being possible, IPv6 over IEEE 802.11-OCB must 1349 implement an distributed mechanism to authenticate transmitters and 1350 receivers without the support of a DHCP server. 1352 Time synchronization not being available, IPv6 over IEEE 802.11-OCB 1353 must implement a higher layer mechanism for time synchronization 1354 between transmitters and receivers without the support of a NTP 1355 server. 1357 The IEEE 802.11-OCB link being asymmetric, IPv6 over IEEE 802.11-OCB 1358 must disable management mechanisms requesting acknowledgements or 1359 replies. 1361 The IEEE 802.11-OCB link having a short duration time, IPv6 over IEEE 1362 802.11-OCB should implement fast IPv6 mobility management mechanisms. 1364 F.3. Multiple interfaces 1366 There are considerations for 2 or more IEEE 802.11-OCB interface 1367 cards per vehicle. For each vehicle taking part in road traffic, one 1368 IEEE 802.11-OCB interface card could be fully allocated for Non IP 1369 safety-critical communication. Any other IEEE 802.11-OCB may be used 1370 for other type of traffic. 1372 The mode of operation of these other wireless interfaces is not 1373 clearly defined yet. One possibility is to consider each card as an 1374 independent network interface, with a specific MAC Address and a set 1375 of IPv6 addresses. Another possibility is to consider the set of 1376 these wireless interfaces as a single network interface (not 1377 including the IEEE 802.11-OCB interface used by Non IP safety 1378 critical communications). This will require specific logic to 1379 ensure, for example, that packets meant for a vehicle in front are 1380 actually sent by the radio in the front, or that multiple copies of 1381 the same packet received by multiple interfaces are treated as a 1382 single packet. Treating each wireless interface as a separate 1383 network interface pushes such issues to the application layer. 1385 Certain privacy requirements imply that if these multiple interfaces 1386 are represented by many network interface, a single renumbering event 1387 shall cause renumbering of all these interfaces. If one MAC changed 1388 and another stayed constant, external observers would be able to 1389 correlate old and new values, and the privacy benefits of 1390 randomization would be lost. 1392 The privacy requirements of Non IP safety-critical communications 1393 imply that if a change of pseudonyme occurs, renumbering of all other 1394 interfaces shall also occur. 1396 F.4. MAC Address Generation 1398 When designing the IPv6 over 802.11-OCB address mapping, we assume 1399 that the MAC Addresses change during well defined "renumbering 1400 events". The 48 bits randomized MAC addresses will have the 1401 following characteristics: 1403 o Bit "Local/Global" set to "locally admninistered". 1405 o Bit "Unicast/Multicast" set to "Unicast". 1407 o 46 remaining bits set to a random value, using a random number 1408 generator that meets the requirements of [RFC4086]. 1410 The way to meet the randomization requirements is to retain 46 bits 1411 from the output of a strong hash function, such as SHA256, taking as 1412 input a 256 bit local secret, the "nominal" MAC Address of the 1413 interface, and a representation of the date and time of the 1414 renumbering event. 1416 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode 1418 For information, at the time of writing, this is the list of IEEE 1419 802.11 messages that may be transmitted in OCB mode, i.e. when 1420 dot11OCBActivated is true in a STA: 1422 o The STA may send management frames of subtype Action and, if the 1423 STA maintains a TSF Timer, subtype Timing Advertisement; 1425 o The STA may send control frames, except those of subtype PS-Poll, 1426 CF-End, and CF-End plus CFAck; 1428 o The STA may send data frames of subtype Data, Null, QoS Data, and 1429 QoS Null. 1431 Appendix H. Implementation Status 1433 This section describes an example of an IPv6 Packet captured over a 1434 IEEE 802.11-OCB link. 1436 By way of example we show that there is no modification in the 1437 headers when transmitted over 802.11-OCB networks - they are 1438 transmitted like any other 802.11 and Ethernet packets. 1440 We describe an experiment of capturing an IPv6 packet on an 1441 802.11-OCB link. In topology depicted in Figure 6, the packet is an 1442 IPv6 Router Advertisement. This packet is emitted by a Router on its 1443 802.11-OCB interface. The packet is captured on the Host, using a 1444 network protocol analyzer (e.g. Wireshark); the capture is performed 1445 in two different modes: direct mode and 'monitor' mode. The topology 1446 used during the capture is depicted below. 1448 +--------+ +-------+ 1449 | | 802.11-OCB Link | | 1450 ---| Router |--------------------------------| Host | 1451 | | | | 1452 +--------+ +-------+ 1454 Figure 6: Topology for capturing IP packets on 802.11-OCB 1456 During several capture operations running from a few moments to 1457 several hours, no message relevant to the BSSID contexts were 1458 captured (no Association Request/Response, Authentication Req/Resp, 1459 Beacon). This shows that the operation of 802.11-OCB is outside the 1460 context of a BSSID. 1462 Overall, the captured message is identical with a capture of an IPv6 1463 packet emitted on a 802.11b interface. The contents are precisely 1464 similar. 1466 H.1. Capture in Monitor Mode 1468 The IPv6 RA packet captured in monitor mode is illustrated below. 1469 The radio tap header provides more flexibility for reporting the 1470 characteristics of frames. The Radiotap Header is prepended by this 1471 particular stack and operating system on the Host machine to the RA 1472 packet received from the network (the Radiotap Header is not present 1473 on the air). The implementation-dependent Radiotap Header is useful 1474 for piggybacking PHY information from the chip's registers as data in 1475 a packet understandable by userland applications using Socket 1476 interfaces (the PHY interface can be, for example: power levels, data 1477 rate, ratio of signal to noise). 1479 The packet present on the air is formed by IEEE 802.11 Data Header, 1480 Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. 1482 Radiotap Header v0 1483 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1484 |Header Revision| Header Pad | Header length | 1485 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1486 | Present flags | 1487 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1488 | Data Rate | Pad | 1489 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1491 IEEE 802.11 Data Header 1492 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1493 | Type/Subtype and Frame Ctrl | Duration | 1494 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1495 | Receiver Address... 1496 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1497 ... Receiver Address | Transmitter Address... 1498 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1499 ... Transmitter Address | 1500 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1501 | BSS Id... 1502 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1503 ... BSS Id | Frag Number and Seq Number | 1504 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1506 Logical-Link Control Header 1507 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1508 | DSAP |I| SSAP |C| Control field | Org. code... 1509 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1510 ... Organizational Code | Type | 1511 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1513 IPv6 Base Header 1514 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1515 |Version| Traffic Class | Flow Label | 1516 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1517 | Payload Length | Next Header | Hop Limit | 1518 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1519 | | 1520 + + 1521 | | 1522 + Source Address + 1523 | | 1524 + + 1525 | | 1526 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1527 | | 1528 + + 1529 | | 1530 + Destination Address + 1531 | | 1532 + + 1533 | | 1534 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1536 Router Advertisement 1537 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1538 | Type | Code | Checksum | 1539 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1540 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1541 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1542 | Reachable Time | 1543 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1544 | Retrans Timer | 1545 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1546 | Options ... 1547 +-+-+-+-+-+-+-+-+-+-+-+- 1549 The value of the Data Rate field in the Radiotap header is set to 6 1550 Mb/s. This indicates the rate at which this RA was received. 1552 The value of the Transmitter address in the IEEE 802.11 Data Header 1553 is set to a 48bit value. The value of the destination address is 1554 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS 1555 Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network 1556 protocol analyzer as being "broadcast". The Fragment number and 1557 sequence number fields are together set to 0x90C6. 1559 The value of the Organization Code field in the Logical-Link Control 1560 Header is set to 0x0, recognized as "Encapsulated Ethernet". The 1561 value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise 1562 #86DD), recognized as "IPv6". 1564 A Router Advertisement is periodically sent by the router to 1565 multicast group address ff02::1. It is an icmp packet type 134. The 1566 IPv6 Neighbor Discovery's Router Advertisement message contains an 1567 8-bit field reserved for single-bit flags, as described in [RFC4861]. 1569 The IPv6 header contains the link local address of the router 1570 (source) configured via EUI-64 algorithm, and destination address set 1571 to ff02::1. Recent versions of network protocol analyzers (e.g. 1572 Wireshark) provide additional informations for an IP address, if a 1573 geolocalization database is present. In this example, the 1574 geolocalization database is absent, and the "GeoIP" information is 1575 set to unknown for both source and destination addresses (although 1576 the IPv6 source and destination addresses are set to useful values). 1577 This "GeoIP" can be a useful information to look up the city, 1578 country, AS number, and other information for an IP address. 1580 The Ethernet Type field in the logical-link control header is set to 1581 0x86dd which indicates that the frame transports an IPv6 packet. In 1582 the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 1583 which is the corresponding multicast MAC address. The BSS id is a 1584 broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link 1585 duration between vehicles and the roadside infrastructure, there is 1586 no need in IEEE 802.11-OCB to wait for the completion of association 1587 and authentication procedures before exchanging data. IEEE 1588 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) 1589 and may start communicating as soon as they arrive on the 1590 communication channel. 1592 H.2. Capture in Normal Mode 1594 The same IPv6 Router Advertisement packet described above (monitor 1595 mode) is captured on the Host, in the Normal mode, and depicted 1596 below. 1598 Ethernet II Header 1599 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1600 | Destination... 1601 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1602 ...Destination | Source... 1603 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1604 ...Source | 1605 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1606 | Type | 1607 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1609 IPv6 Base Header 1610 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1611 |Version| Traffic Class | Flow Label | 1612 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1613 | Payload Length | Next Header | Hop Limit | 1614 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1615 | | 1616 + + 1617 | | 1618 + Source Address + 1619 | | 1620 + + 1621 | | 1622 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1623 | | 1624 + + 1625 | | 1626 + Destination Address + 1627 | | 1628 + + 1629 | | 1630 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1632 Router Advertisement 1633 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1634 | Type | Code | Checksum | 1635 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1636 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1637 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1638 | Reachable Time | 1639 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1640 | Retrans Timer | 1641 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1642 | Options ... 1643 +-+-+-+-+-+-+-+-+-+-+-+- 1645 One notices that the Radiotap Header, the IEEE 802.11 Data Header and 1646 the Logical-Link Control Headers are not present. On the other hand, 1647 a new header named Ethernet II Header is present. 1649 The Destination and Source addresses in the Ethernet II header 1650 contain the same values as the fields Receiver Address and 1651 Transmitter Address present in the IEEE 802.11 Data Header in the 1652 "monitor" mode capture. 1654 The value of the Type field in the Ethernet II header is 0x86DD 1655 (recognized as "IPv6"); this value is the same value as the value of 1656 the field Type in the Logical-Link Control Header in the "monitor" 1657 mode capture. 1659 The knowledgeable experimenter will no doubt notice the similarity of 1660 this Ethernet II Header with a capture in normal mode on a pure 1661 Ethernet cable interface. 1663 An Adaptation layer is inserted on top of a pure IEEE 802.11 MAC 1664 layer, in order to adapt packets, before delivering the payload data 1665 to the applications. It adapts 802.11 LLC/MAC headers to Ethernet II 1666 headers. In further detail, this adaptation consists in the 1667 elimination of the Radiotap, 802.11 and LLC headers, and in the 1668 insertion of the Ethernet II header. In this way, IPv6 runs straight 1669 over LLC over the 802.11-OCB MAC layer; this is further confirmed by 1670 the use of the unique Type 0x86DD. 1672 Authors' Addresses 1674 Alexandre Petrescu 1675 CEA, LIST 1676 CEA Saclay 1677 Gif-sur-Yvette , Ile-de-France 91190 1678 France 1680 Phone: +33169089223 1681 Email: Alexandre.Petrescu@cea.fr 1683 Nabil Benamar 1684 Moulay Ismail University 1685 Morocco 1687 Phone: +212670832236 1688 Email: n.benamar@est.umi.ac.ma 1689 Jerome Haerri 1690 Eurecom 1691 Sophia-Antipolis 06904 1692 France 1694 Phone: +33493008134 1695 Email: Jerome.Haerri@eurecom.fr 1697 Jong-Hyouk Lee 1698 Sangmyung University 1699 31, Sangmyeongdae-gil, Dongnam-gu 1700 Cheonan 31066 1701 Republic of Korea 1703 Email: jonghyouk@smu.ac.kr 1705 Thierry Ernst 1706 YoGoKo 1707 France 1709 Email: thierry.ernst@yogoko.fr