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Is this intentional? -- Found something which looks like a code comment -- if you have code sections in the document, please surround them with '' and '' lines. Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 2818 (Obsoleted by RFC 9110) ** Downref: Normative reference to an Informational RFC: RFC 3753 ** Downref: Normative reference to an Informational RFC: RFC 5889 ** Downref: Normative reference to an Informational RFC: RFC 7721 Summary: 4 errors (**), 0 flaws (~~), 1 warning (==), 2 comments (--). 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 23, 2018 Moulay Ismail University 6 J. Haerri 7 Eurecom 8 J. Lee 9 Sangmyung University 10 T. Ernst 11 YoGoKo 12 February 19, 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-18.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 23, 2018. 47 Copyright Notice 49 Copyright (c) 2018 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (https://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with respect 57 to this document. Code Components extracted from this document must 58 include Simplified BSD License text as described in Section 4.e of 59 the Trust Legal Provisions and are provided without warranty as 60 described in the Simplified BSD License. 62 Table of Contents 64 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 65 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 66 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 4 67 4. IPv6 over 802.11-OCB . . . . . . . . . . . . . . . . . . . . 5 68 4.1. Maximum Transmission Unit (MTU) . . . . . . . . . . . . . 5 69 4.2. Frame Format . . . . . . . . . . . . . . . . . . . . . . 5 70 4.2.1. Ethernet Adaptation Layer . . . . . . . . . . . . . . 5 71 4.3. Link-Local Addresses . . . . . . . . . . . . . . . . . . 8 72 4.4. Address Mapping . . . . . . . . . . . . . . . . . . . . . 8 73 4.4.1. Address Mapping -- Unicast . . . . . . . . . . . . . 8 74 4.4.2. Address Mapping -- Multicast . . . . . . . . . . . . 8 75 4.5. Stateless Autoconfiguration . . . . . . . . . . . . . . . 8 76 4.6. Subnet Structure . . . . . . . . . . . . . . . . . . . . 9 77 5. Security Considerations . . . . . . . . . . . . . . . . . . . 10 78 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 79 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 11 80 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11 81 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 82 9.1. Normative References . . . . . . . . . . . . . . . . . . 12 83 9.2. Informative References . . . . . . . . . . . . . . . . . 14 84 Appendix A. ChangeLog . . . . . . . . . . . . . . . . . . . . . 16 85 Appendix B. 802.11p . . . . . . . . . . . . . . . . . . . . . . 23 86 Appendix C. Aspects introduced by the OCB mode to 802.11 . . . . 23 87 Appendix D. Changes Needed on a software driver 802.11a to 88 become a 802.11-OCB driver . . . 27 89 Appendix E. EtherType Protocol Discrimination (EPD) . . . . . . 28 90 Appendix F. Design Considerations . . . . . . . . . . . . . . . 29 91 F.1. Vehicle ID . . . . . . . . . . . . . . . . . . . . . . . 29 92 F.2. Reliability Requirements . . . . . . . . . . . . . . . . 30 93 F.3. Multiple interfaces . . . . . . . . . . . . . . . . . . . 30 94 F.4. MAC Address Generation . . . . . . . . . . . . . . . . . 31 96 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode . . . . 31 97 Appendix H. Implementation Status . . . . . . . . . . . . . . . 32 98 H.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . 33 99 H.2. Capture in Normal Mode . . . . . . . . . . . . . . . . . 35 100 Appendix I. Extra Terminology . . . . . . . . . . . . . . . . . 37 101 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 38 103 1. Introduction 105 This document describes the transmission of IPv6 packets on IEEE Std 106 802.11-OCB networks [IEEE-802.11-2016] (a.k.a "802.11p" see 107 Appendix B). This involves the layering of IPv6 networking on top of 108 the IEEE 802.11 MAC layer, with an LLC layer. Compared to running 109 IPv6 over the Ethernet MAC layer, there is no modification expected 110 to IEEE Std 802.11 MAC and Logical Link sublayers: IPv6 works fine 111 directly over 802.11-OCB too, with an LLC layer. 113 The IPv6 network layer operates on 802.11-OCB in the same manner as 114 operating on Ethernet, but there are two kinds of exceptions: 116 o Exceptions due to different operation of IPv6 network layer on 117 802.11 than on Ethernet. To satisfy these exceptions, this 118 document describes an Ethernet Adaptation Layer between Ethernet 119 headers and 802.11 headers. The Ethernet Adaptation Layer is 120 described Section 4.2.1. The operation of IP on Ethernet is 121 described in [RFC1042], [RFC2464] and 122 [I-D.hinden-6man-rfc2464bis]. 124 o Exceptions due to the OCB nature of 802.11-OCB compared to 802.11. 125 This has impacts on security, privacy, subnet structure and 126 handover behaviour. For security and privacy recommendations see 127 Section 5 and Section 4.5. The subnet structure is described in 128 Section 4.6. The handover behaviour on OCB links is not described 129 in this document. 131 In the published literature, many documents describe aspects and 132 problems related to running IPv6 over 802.11-OCB: 133 [I-D.ietf-ipwave-vehicular-networking-survey]. 135 2. Terminology 137 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 138 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 139 document are to be interpreted as described in RFC 2119 [RFC2119]. 141 IP-OBU (Internet Protocol On-Board Unit): an IP-OBU is a computer 142 situated in a vehicle such as an automobile, bicycle, or similar. It 143 has at least one IP interface that runs in mode OCB of 802.11, and 144 that has an "OBU" transceiver. See the definition of the term "OBU" 145 in section Appendix I. 147 IP-RSU (IP Road-Side Unit): an IP-RSU is situated along the road. An 148 IP-RSU has at least two distinct IP-enabled interfaces; at least one 149 interface is operated in mode OCB of IEEE 802.11 and is IP-enabled. 150 An IP-RSU is similar to a Wireless Termination Point (WTP), as 151 defined in [RFC5415], or an Access Point (AP), as defined in IEEE 152 documents, or an Access Network Router (ANR) defined in [RFC3753], 153 with one key particularity: the wireless PHY/MAC layer of at least 154 one of its IP-enabled interfaces is configured to operate in 155 802.11-OCB mode. The IP-RSU communicates with the IP-OBU in the 156 vehicle over 802.11 wireless link operating in OCB mode. 158 OCB (outside the context of a basic service set - BSS): A mode of 159 operation in which a STA is not a member of a BSS and does not 160 utilize IEEE Std 802.11 authentication, association, or data 161 confidentiality. 163 802.11-OCB: mode specified in IEEE Std 802.11-2016 when the MIB 164 attribute dot11OCBActivited is true. The OCB mode requires 165 transmission of QoS data frames (IEEE Std 802.11e), half-clocked 166 operation (IEEE Std 802.11j), and use of 5.9 GHz frequency band. 167 Nota: any implementation should comply with standards and regulations 168 set in the different countries for using that frequency band. 170 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 172 The IEEE 802.11-OCB Networks are used for vehicular communications, 173 as 'Wireless Access in Vehicular Environments'. The IP communication 174 scenarios for these environments have been described in several 175 documents; in particular, we refer the reader to 176 [I-D.ietf-ipwave-vehicular-networking-survey], that lists some 177 scenarios and requirements for IP in Intelligent Transportation 178 Systems. 180 The link model is the following: STA --- 802.11-OCB --- STA. In 181 vehicular networks, STAs can be IP-RSUs and/or IP-OBUs. While 182 802.11-OCB is clearly specified, and the use of IPv6 over such link 183 is not radically new, the operating environment (vehicular networks) 184 brings in new perspectives. 186 The mechanisms for forming and terminating, discovering, peering and 187 mobility management for 802.11-OCB links are not described in this 188 document. 190 4. IPv6 over 802.11-OCB 192 4.1. Maximum Transmission Unit (MTU) 194 The default MTU for IP packets on 802.11-OCB MUST be 1500 octets. It 195 is the same value as IPv6 packets on Ethernet links, as specified in 196 [RFC2464]. This value of the MTU respects the recommendation that 197 every link on the Internet must have a minimum MTU of 1280 octets 198 (stated in [RFC8200], and the recommendations therein, especially 199 with respect to fragmentation). If IPv6 packets of size larger than 200 the MTU are sent on an 802.11-OCB interface card then the IP stack 201 MUST fragment. In case there are IPv6 fragments, the subfield 202 "Fragment number" within the field "Sequence control" of the 802.11 203 Data header containing the IPv6 fragment is increased by the MAC 204 layer. 206 Non-IP packets such as WAVE Short Message Protocol (WSMP) can be 207 delivered on 802.11-OCB links. Specifications of these packets are 208 out of scope of this document, and do not impose any limit on the MTU 209 size, allowing an arbitrary number of 'containers'. Non-IP packets 210 such as ETSI GeoNetworking packets have an MTU of 1492 bytes. The 211 operation of IPv6 over GeoNetworking is specified at 212 [ETSI-IPv6-GeoNetworking]. 214 4.2. Frame Format 216 IP packets are transmitted over 802.11-OCB as standard Ethernet 217 packets. As with all 802.11 frames, an Ethernet adaptation layer is 218 used with 802.11-OCB as well. This Ethernet Adaptation Layer 219 performing 802.11-to-Ethernet is described in Section 4.2.1. The 220 Ethernet Type code (EtherType) for IPv6 MUST be 0x86DD (hexadecimal 221 86DD, or otherwise #86DD). 223 The Frame format for transmitting IPv6 on 802.11-OCB networks is the 224 same as transmitting IPv6 on Ethernet networks, and is described in 225 section 3 of [RFC2464]. 227 1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1 228 is the binary representation of the EtherType value 0x86DD. 230 4.2.1. Ethernet Adaptation Layer 232 An 'adaptation' layer is inserted between a MAC layer and the 233 Networking layer. This is used to transform some parameters between 234 their form expected by the IP stack and the form provided by the MAC 235 layer. 237 An Ethernet Adaptation Layer makes an 802.11 MAC look to IP 238 Networking layer as a more traditional Ethernet layer. At reception, 239 this layer takes as input the IEEE 802.11 Data Header and the 240 Logical-Link Layer Control Header and produces an Ethernet II Header. 241 At sending, the reverse operation is performed. 243 The operation of the Ethernet Adaptation Layer is depicted by the 244 double arrow in Figure 1. 246 +--------------------+------------+-------------+---------+-----------+ 247 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer| 248 +--------------------+------------+-------------+---------+-----------+ 249 \ / \ / 250 ----------------------------- -------- 251 \---------------------------------------------/ 252 ^ 253 | 254 802.11-to-Ethernet Adaptation Layer 255 | 256 v 257 +---------------------+-------------+---------+ 258 | Ethernet II Header | IPv6 Header | Payload | 259 +---------------------+-------------+---------+ 261 Figure 1: Operation of the Ethernet Adaptation Layer 263 The Receiver and Transmitter Address fields in the 802.11 Data Header 264 MUST contain the same values as the Destination and the Source 265 Address fields in the Ethernet II Header, respectively. The value of 266 the Type field in the LLC Header MUST be the same as the value of the 267 Type field in the Ethernet II Header. 269 The ".11 Trailer" contains solely a 4-byte Frame Check Sequence. 271 Additionally, the Ethernet Adaptation Layer performs operations in 272 relation to IP fragmentation and MTU. One of these operations is 273 briefly described in Section 4.1. 275 In OCB mode, IPv6 packets MAY be transmitted either as "IEEE 802.11 276 Data" or alternatively as "IEEE 802.11 QoS Data", as illustrated in 277 Figure 2. 279 +--------------------+-------------+-------------+---------+-----------+ 280 | 802.11 Data Header | LLC Header | IPv6 Header | Payload |.11 Trailer| 281 +--------------------+-------------+-------------+---------+-----------+ 283 or 285 +--------------------+-------------+-------------+---------+-----------+ 286 | 802.11 QoS Data Hdr| LLC Header | IPv6 Header | Payload |.11 Trailer| 287 +--------------------+-------------+-------------+---------+-----------+ 289 Figure 2: 802.11 Data Header or 802.11 QoS Data Header 291 The distinction between the two formats is given by the value of the 292 field "Type/Subtype". The value of the field "Type/Subtype" in the 293 802.11 Data header is 0x0020. The value of the field "Type/Subtype" 294 in the 802.11 QoS header is 0x0028. 296 The mapping between qos-related fields in the IPv6 header (e.g. 297 "Traffic Class", "Flow label") and fields in the "802.11 QoS Data 298 Header" (e.g. "QoS Control") are not specified in this document. 299 Guidance for a potential mapping is provided in 300 [I-D.ietf-tsvwg-ieee-802-11], although it is not specific to OCB 301 mode. 303 The placement of IPv6 networking layer on Ethernet Adaptation Layer 304 is illustrated in Figure 3. 306 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 307 | IPv6 | 308 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 309 | Ethernet Adaptation Layer | 310 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 311 | 802.11 MAC | 312 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 313 | 802.11 PHY | 314 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 316 Figure 3: Ethernet Adaptation Layer stacked with other layers 318 (in the above figure, a 802.11 profile is represented; this is used 319 also for 802.11 OCB profile.) 321 Other alternative views of layering are EtherType Protocol 322 Discrimination (EPD), see Appendix E, and SNAP see [RFC1042]. 324 4.3. Link-Local Addresses 326 The link-local address of an 802.11-OCB interface is formed in the 327 same manner as on an Ethernet interface. This manner is described in 328 section 5 of [RFC2464]. Additionally, if stable identifiers are 329 needed, it is recommended to follow the Recommendation on Stable IPv6 330 Interface Identifiers [RFC8064]. Additionally, if semantically 331 opaque Interface Identifiers are needed, a potential method for 332 generating semantically opaque Interface Identifiers with IPv6 333 Stateless Address Autoconfiguration is given in [RFC7217]. 335 4.4. Address Mapping 337 For unicast as for multicast, there is no change from the unicast and 338 multicast address mapping format of Ethernet interfaces, as defined 339 by sections 6 and 7 of [RFC2464]. 341 4.4.1. Address Mapping -- Unicast 343 The procedure for mapping IPv6 unicast addresses into Ethernet link- 344 layer addresses is described in [RFC4861]. 346 4.4.2. Address Mapping -- Multicast 348 The multicast address mapping is performed according to the method 349 specified in section 7 of [RFC2464]. The meaning of the value "3333" 350 mentioned in that section 7 of [RFC2464] is defined in section 2.3.1 351 of [RFC7042]. 353 Transmitting IPv6 packets to multicast destinations over 802.11 links 354 proved to have some performance issues 355 [I-D.perkins-intarea-multicast-ieee802]. These issues may be 356 exacerbated in OCB mode. Solutions for these problems should 357 consider the OCB mode of operation. 359 4.5. Stateless Autoconfiguration 361 The Interface Identifier for an 802.11-OCB interface is formed using 362 the same rules as the Interface Identifier for an Ethernet interface; 363 this is described in section 4 of [RFC2464]. No changes are needed, 364 but some care must be taken when considering the use of the Stateless 365 Address Auto-Configuration procedure. 367 The bits in the interface identifier have no generic meaning and the 368 identifier should be treated as an opaque value. The bits 369 'Universal' and 'Group' in the identifier of an 802.11-OCB interface 370 are significant, as this is an IEEE link-layer address. The details 371 of this significance are described in [RFC7136]. 373 As with all Ethernet and 802.11 interface identifiers ([RFC7721]), 374 the identifier of an 802.11-OCB interface may involve privacy, MAC 375 address spoofing and IP address hijacking risks. A vehicle embarking 376 an OBU or an IP-OBU whose egress interface is 802.11-OCB may expose 377 itself to eavesdropping and subsequent correlation of data; this may 378 reveal data considered private by the vehicle owner; there is a risk 379 of being tracked; see the privacy considerations described in 380 Appendix F. 382 If stable Interface Identifiers are needed in order to form IPv6 383 addresses on 802.11-OCB links, it is recommended to follow the 384 recommendation in [RFC8064]. Additionally, if semantically opaque 385 Interface Identifiers are needed, a potential method for generating 386 semantically opaque Interface Identifiers with IPv6 Stateless Address 387 Autoconfiguration is given in [RFC7217]. 389 4.6. Subnet Structure 391 A subnet is formed by the external 802.11-OCB interfaces of vehicles 392 that are in close range (not their on-board interfaces). This 393 ephemeral subnet structure is strongly influenced by the mobility of 394 vehicles: the 802.11 hidden node effects appear. On another hand, 395 the structure of the internal subnets in each car is relatively 396 stable. 398 The 802.11 networks in OCB mode may be considered as 'ad-hoc' 399 networks. The addressing model for such networks is described in 400 [RFC5889]. 402 An addressing model involves several types of addresses, like 403 Globally-unique Addresses (GUA), Link-Local Addresses (LL) and Unique 404 Local Addresses (ULA). The subnet structure in 'ad-hoc' networks may 405 have characteristics that lead to difficulty of using GUAs derived 406 from a received prefix, but the LL addresses may be easier to use 407 since the prefix is constant. 409 The operation of the Neighbor Discovery protocol (ND) over 802.11 OCB 410 links is different than over 802.11 links. In OCB, the link layer 411 does not ensure that all associated members receive all messages, 412 because there is no association operation. The operation of ND over 413 802.11 OCB is not specified in this document. 415 The operation of the Mobile IPv6 protocol over 802.11 OCB links is 416 different than on other links. The Movement Detection operation 417 (section 11.5.1 of [RFC6275]) can not rely on Neighbor Unreachability 418 Detection operation of the Neighbor Discovery protocol, for the 419 reason mentioned in the previous paragraph. Also, the 802.11 OCB 420 link layer is not a lower layer that can provide an indication that a 421 link layer handover has occured. The operation of the Mobile IPv6 422 protocol over 802.11 OCB is not specified in this document. 424 5. Security Considerations 426 Any security mechanism at the IP layer or above that may be carried 427 out for the general case of IPv6 may also be carried out for IPv6 428 operating over 802.11-OCB. 430 The OCB operation is stripped off of all existing 802.11 link-layer 431 security mechanisms. There is no encryption applied below the 432 network layer running on 802.11-OCB. At application layer, the IEEE 433 1609.2 document [IEEE-1609.2] does provide security services for 434 certain applications to use; application-layer mechanisms are out-of- 435 scope of this document. On another hand, a security mechanism 436 provided at networking layer, such as IPsec [RFC4301], may provide 437 data security protection to a wider range of applications. 439 802.11-OCB does not provide any cryptographic protection, because it 440 operates outside the context of a BSS (no Association Request/ 441 Response, no Challenge messages). Any attacker can therefore just 442 sit in the near range of vehicles, sniff the network (just set the 443 interface card's frequency to the proper range) and perform attacks 444 without needing to physically break any wall. Such a link is less 445 protected than commonly used links (wired link or protected 802.11). 447 The potential attack vectors are: MAC address spoofing, IP address 448 and session hijacking and privacy violation. 450 Within the IPsec Security Architecture [RFC4301], the IPsec AH and 451 ESP headers [RFC4302] and [RFC4303] respectively, its multicast 452 extensions [RFC5374], HTTPS [RFC2818] and SeND [RFC3971] protocols 453 can be used to protect communications. Further, the assistance of 454 proper Public Key Infrastructure (PKI) protocols [RFC4210] is 455 necessary to establish credentials. More IETF protocols are 456 available in the toolbox of the IP security protocol designer. 457 Certain ETSI protocols related to security protocols in Intelligent 458 Transportation Systems are described in [ETSI-sec-archi]. 460 As with all Ethernet and 802.11 interface identifiers, there may 461 exist privacy risks in the use of 802.11-OCB interface identifiers. 462 Moreover, in outdoors vehicular settings, the privacy risks are more 463 important than in indoors settings. New risks are induced by the 464 possibility of attacker sniffers deployed along routes which listen 465 for IP packets of vehicles passing by. For this reason, in the 466 802.11-OCB deployments, there is a strong necessity to use protection 467 tools such as dynamically changing MAC addresses. This may help 468 mitigate privacy risks to a certain level. On another hand, it may 469 have an impact in the way typical IPv6 address auto-configuration is 470 performed for vehicles (SLAAC would rely on MAC addresses and would 471 hence dynamically change the affected IP address), in the way the 472 IPv6 Privacy addresses were used, and other effects. 474 6. IANA Considerations 476 No request to IANA. 478 7. Contributors 480 Christian Huitema, Tony Li. 482 Romain Kuntz contributed extensively about IPv6 handovers between 483 links running outside the context of a BSS (802.11-OCB links). 485 Tim Leinmueller contributed the idea of the use of IPv6 over 486 802.11-OCB for distribution of certificates. 488 Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey 489 Voronov provided significant feedback on the experience of using IP 490 messages over 802.11-OCB in initial trials. 492 Michelle Wetterwald contributed extensively the MTU discussion, 493 offered the ETSI ITS perspective, and reviewed other parts of the 494 document. 496 8. Acknowledgements 498 The authors would like to thank Witold Klaudel, Ryuji Wakikawa, 499 Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan 500 Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray 501 Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, 502 Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne, 503 Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark, 504 Bob Moskowitz, Andrew (Dryden?), Georg Mayer, Dorothy Stanley, Sandra 505 Cespedes, Mariano Falcitelli, Sri Gundavelli, Abdussalam Baryun, 506 Margaret Cullen, Erik Kline, Carlos Jesus Bernardos Cano and William 507 Whyte. Their valuable comments clarified particular issues and 508 generally helped to improve the document. 510 Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB 511 drivers for linux and described how. 513 For the multicast discussion, the authors would like to thank Owen 514 DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and 515 participants to discussions in network working groups. 517 The authors would like to thank participants to the Birds-of- 518 a-Feather "Intelligent Transportation Systems" meetings held at IETF 519 in 2016. 521 9. References 523 9.1. Normative References 525 [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission 526 of IP datagrams over IEEE 802 networks", STD 43, RFC 1042, 527 DOI 10.17487/RFC1042, February 1988, 528 . 530 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 531 Requirement Levels", BCP 14, RFC 2119, 532 DOI 10.17487/RFC2119, March 1997, 533 . 535 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 536 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 537 . 539 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 540 DOI 10.17487/RFC2818, May 2000, 541 . 543 [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related 544 Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, 545 . 547 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 548 "SEcure Neighbor Discovery (SEND)", RFC 3971, 549 DOI 10.17487/RFC3971, March 2005, 550 . 552 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 553 "Randomness Requirements for Security", BCP 106, RFC 4086, 554 DOI 10.17487/RFC4086, June 2005, 555 . 557 [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, 558 "Internet X.509 Public Key Infrastructure Certificate 559 Management Protocol (CMP)", RFC 4210, 560 DOI 10.17487/RFC4210, September 2005, 561 . 563 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 564 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 565 December 2005, . 567 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 568 DOI 10.17487/RFC4302, December 2005, 569 . 571 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 572 RFC 4303, DOI 10.17487/RFC4303, December 2005, 573 . 575 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 576 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 577 DOI 10.17487/RFC4861, September 2007, 578 . 580 [RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast 581 Extensions to the Security Architecture for the Internet 582 Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008, 583 . 585 [RFC5415] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, 586 Ed., "Control And Provisioning of Wireless Access Points 587 (CAPWAP) Protocol Specification", RFC 5415, 588 DOI 10.17487/RFC5415, March 2009, 589 . 591 [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing 592 Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889, 593 September 2010, . 595 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 596 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 597 2011, . 599 [RFC7042] Eastlake 3rd, D. and J. Abley, "IANA Considerations and 600 IETF Protocol and Documentation Usage for IEEE 802 601 Parameters", BCP 141, RFC 7042, DOI 10.17487/RFC7042, 602 October 2013, . 604 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 605 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 606 February 2014, . 608 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 609 Interface Identifiers with IPv6 Stateless Address 610 Autoconfiguration (SLAAC)", RFC 7217, 611 DOI 10.17487/RFC7217, April 2014, 612 . 614 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 615 Considerations for IPv6 Address Generation Mechanisms", 616 RFC 7721, DOI 10.17487/RFC7721, March 2016, 617 . 619 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 620 "Recommendation on Stable IPv6 Interface Identifiers", 621 RFC 8064, DOI 10.17487/RFC8064, February 2017, 622 . 624 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 625 (IPv6) Specification", STD 86, RFC 8200, 626 DOI 10.17487/RFC8200, July 2017, 627 . 629 9.2. Informative References 631 [ETSI-IPv6-GeoNetworking] 632 "ETSI EN 302 636-6-1 v1.2.1 (2014-05), ETSI, European 633 Standard, Intelligent Transportation Systems (ITS); 634 Vehicular Communications; Geonetworking; Part 6: Internet 635 Integration; Sub-part 1: Transmission of IPv6 Packets over 636 Geonetworking Protocols. Downloaded on September 9th, 637 2017, freely available from ETSI website at URL 638 http://www.etsi.org/deliver/ 639 etsi_en/302600_302699/30263601/01.02.01_60/ 640 en_30263601v010201p.pdf". 642 [ETSI-sec-archi] 643 "ETSI TS 102 940 V1.2.1 (2016-11), ETSI Technical 644 Specification, Intelligent Transport Systems (ITS); 645 Security; ITS communications security architecture and 646 security management, November 2016. Downloaded on 647 September 9th, 2017, freely available from ETSI website at 648 URL http://www.etsi.org/deliver/ 649 etsi_ts/102900_102999/102940/01.02.01_60/ 650 ts_102940v010201p.pdf". 652 [I-D.hinden-6man-rfc2464bis] 653 Crawford, M. and R. Hinden, "Transmission of IPv6 Packets 654 over Ethernet Networks", draft-hinden-6man-rfc2464bis-02 655 (work in progress), March 2017. 657 [I-D.ietf-ipwave-vehicular-networking-survey] 658 Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M. 659 Wetterwald, "Survey on IP-based Vehicular Networking for 660 Intelligent Transportation Systems", draft-ietf-ipwave- 661 vehicular-networking-survey-00 (work in progress), July 662 2017. 664 [I-D.ietf-tsvwg-ieee-802-11] 665 Szigeti, T., Henry, J., and F. Baker, "Diffserv to IEEE 666 802.11 Mapping", draft-ietf-tsvwg-ieee-802-11-11 (work in 667 progress), December 2017. 669 [I-D.perkins-intarea-multicast-ieee802] 670 Perkins, C., Stanley, D., Kumari, W., and J. Zuniga, 671 "Multicast Considerations over IEEE 802 Wireless Media", 672 draft-perkins-intarea-multicast-ieee802-03 (work in 673 progress), July 2017. 675 [IEEE-1609.2] 676 "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access 677 in Vehicular Environments (WAVE) -- Security Services for 678 Applications and Management Messages. Example URL 679 http://ieeexplore.ieee.org/document/7426684/ accessed on 680 August 17th, 2017.". 682 [IEEE-1609.3] 683 "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access 684 in Vehicular Environments (WAVE) -- Networking Services. 685 Example URL http://ieeexplore.ieee.org/document/7458115/ 686 accessed on August 17th, 2017.". 688 [IEEE-1609.4] 689 "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access 690 in Vehicular Environments (WAVE) -- Multi-Channel 691 Operation. Example URL 692 http://ieeexplore.ieee.org/document/7435228/ accessed on 693 August 17th, 2017.". 695 [IEEE-802.11-2016] 696 "IEEE Standard 802.11-2016 - IEEE Standard for Information 697 Technology - Telecommunications and information exchange 698 between systems Local and metropolitan area networks - 699 Specific requirements - Part 11: Wireless LAN Medium 700 Access Control (MAC) and Physical Layer (PHY) 701 Specifications. Status - Active Standard. Description 702 retrieved freely on September 12th, 2017, at URL 703 https://standards.ieee.org/findstds/ 704 standard/802.11-2016.html". 706 [IEEE-802.11p-2010] 707 "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information 708 Technology - Telecommunications and information exchange 709 between systems - Local and metropolitan area networks - 710 Specific requirements, Part 11: Wireless LAN Medium Access 711 Control (MAC) and Physical Layer (PHY) Specifications, 712 Amendment 6: Wireless Access in Vehicular Environments; 713 document freely available at URL 714 http://standards.ieee.org/getieee802/ 715 download/802.11p-2010.pdf retrieved on September 20th, 716 2013.". 718 Appendix A. ChangeLog 720 The changes are listed in reverse chronological order, most recent 721 changes appearing at the top of the list. 723 From draft-ietf-ipwave-ipv6-over-80211ocb-17 to draft-ietf-ipwave- 724 ipv6-over-80211ocb-18 726 o Improved the MTU and fragmentation paragraph. 728 From draft-ietf-ipwave-ipv6-over-80211ocb-16 to draft-ietf-ipwave- 729 ipv6-over-80211ocb-17 731 o Susbtituted "MUST be increased" to "is increased" in the MTU 732 section, about fragmentation. 734 From draft-ietf-ipwave-ipv6-over-80211ocb-15 to draft-ietf-ipwave- 735 ipv6-over-80211ocb-16 737 o Removed the definition of the 'WiFi' term and its occurences. 738 Clarified a phrase that used it in Appendix C "Aspects introduced 739 by the OCB mode to 802.11". 741 o Added more normative words: MUST be 0x86DD, MUST fragment if size 742 larger than MTU, Sequence number in 802.11 Data header MUST be 743 increased. 745 From draft-ietf-ipwave-ipv6-over-80211ocb-14 to draft-ietf-ipwave- 746 ipv6-over-80211ocb-15 748 o Added normative term MUST in two places in section "Ethernet 749 Adaptation Layer". 751 From draft-ietf-ipwave-ipv6-over-80211ocb-13 to draft-ietf-ipwave- 752 ipv6-over-80211ocb-14 753 o Created a new Appendix titled "Extra Terminology" that contains 754 terms DSRC, DSRCS, OBU, RSU as defined outside IETF. Some of them 755 are used in the main Terminology section. 757 o Added two paragraphs explaining that ND and Mobile IPv6 have 758 problems working over 802.11 OCB, yet their adaptations is not 759 specified in this document. 761 From draft-ietf-ipwave-ipv6-over-80211ocb-12 to draft-ietf-ipwave- 762 ipv6-over-80211ocb-13 764 o Substituted "IP-OBU" for "OBRU", and "IP-RSU" for "RSRU" 765 throughout and improved OBU-related definitions in the Terminology 766 section. 768 From draft-ietf-ipwave-ipv6-over-80211ocb-11 to draft-ietf-ipwave- 769 ipv6-over-80211ocb-12 771 o Improved the appendix about "MAC Address Generation" by expressing 772 the technique to be an optional suggestion, not a mandatory 773 mechanism. 775 From draft-ietf-ipwave-ipv6-over-80211ocb-10 to draft-ietf-ipwave- 776 ipv6-over-80211ocb-11 778 o Shortened the paragraph on forming/terminating 802.11-OCB links. 780 o Moved the draft tsvwg-ieee-802-11 to Informative References. 782 From draft-ietf-ipwave-ipv6-over-80211ocb-09 to draft-ietf-ipwave- 783 ipv6-over-80211ocb-10 785 o Removed text requesting a new Group ID for multicast for OCB. 787 o Added a clarification of the meaning of value "3333" in the 788 section Address Mapping -- Multicast. 790 o Added note clarifying that in Europe the regional authority is not 791 ETSI, but "ECC/CEPT based on ENs from ETSI". 793 o Added note stating that the manner in which two STAtions set their 794 communication channel is not described in this document. 796 o Added a time qualifier to state that the "each node is represented 797 uniquely at a certain point in time." 799 o Removed text "This section may need to be moved" (the "Reliability 800 Requirements" section). This section stays there at this time. 802 o In the term definition "802.11-OCB" added a note stating that "any 803 implementation should comply with standards and regulations set in 804 the different countries for using that frequency band." 806 o In the RSU term definition, added a sentence explaining the 807 difference between RSU and RSRU: in terms of number of interfaces 808 and IP forwarding. 810 o Replaced "with at least two IP interfaces" with "with at least two 811 real or virtual IP interfaces". 813 o Added a term in the Terminology for "OBU". However the definition 814 is left empty, as this term is defined outside IETF. 816 o Added a clarification that it is an OBU or an OBRU in this phrase 817 "A vehicle embarking an OBU or an OBRU". 819 o Checked the entire document for a consistent use of terms OBU and 820 OBRU. 822 o Added note saying that "'p' is a letter identifying the 823 Ammendment". 825 o Substituted lower case for capitals SHALL or MUST in the 826 Appendices. 828 o Added reference to RFC7042, helpful in the 3333 explanation. 829 Removed reference to individual submission draft-petrescu-its- 830 scenario-reqs and added reference to draft-ietf-ipwave-vehicular- 831 networking-survey. 833 o Added figure captions, figure numbers, and references to figure 834 numbers instead of 'below'. Replaced "section Section" with 835 "section" throughout. 837 o Minor typographical errors. 839 From draft-ietf-ipwave-ipv6-over-80211ocb-08 to draft-ietf-ipwave- 840 ipv6-over-80211ocb-09 842 o Significantly shortened the Address Mapping sections, by text 843 copied from RFC2464, and rather referring to it. 845 o Moved the EPD description to an Appendix on its own. 847 o Shortened the Introduction and the Abstract. 849 o Moved the tutorial section of OCB mode introduced to .11, into an 850 appendix. 852 o Removed the statement that suggests that for routing purposes a 853 prefix exchange mechanism could be needed. 855 o Removed refs to RFC3963, RFC4429 and RFC6775; these are about ND, 856 MIP/NEMO and oDAD; they were referred in the handover discussion 857 section, which is out. 859 o Updated a reference from individual submission to now a WG item in 860 IPWAVE: the survey document. 862 o Added term definition for WiFi. 864 o Updated the authorship and expanded the Contributors section. 866 o Corrected typographical errors. 868 From draft-ietf-ipwave-ipv6-over-80211ocb-07 to draft-ietf-ipwave- 869 ipv6-over-80211ocb-08 871 o Removed the per-channel IPv6 prohibition text. 873 o Corrected typographical errors. 875 From draft-ietf-ipwave-ipv6-over-80211ocb-06 to draft-ietf-ipwave- 876 ipv6-over-80211ocb-07 878 o Added new terms: OBRU and RSRU ('R' for Router). Refined the 879 existing terms RSU and OBU, which are no longer used throughout 880 the document. 882 o Improved definition of term "802.11-OCB". 884 o Clarified that OCB does not "strip" security, but that the 885 operation in OCB mode is "stripped off of all .11 security". 887 o Clarified that theoretical OCB bandwidth speed is 54mbits, but 888 that a commonly observed bandwidth in IP-over-OCB is 12mbit/s. 890 o Corrected typographical errors, and improved some phrasing. 892 From draft-ietf-ipwave-ipv6-over-80211ocb-05 to draft-ietf-ipwave- 893 ipv6-over-80211ocb-06 895 o Updated references of 802.11-OCB document from -2012 to the IEEE 896 802.11-2016. 898 o In the LL address section, and in SLAAC section, added references 899 to 7217 opaque IIDs and 8064 stable IIDs. 901 From draft-ietf-ipwave-ipv6-over-80211ocb-04 to draft-ietf-ipwave- 902 ipv6-over-80211ocb-05 904 o Lengthened the title and cleanded the abstract. 906 o Added text suggesting LLs may be easy to use on OCB, rather than 907 GUAs based on received prefix. 909 o Added the risks of spoofing and hijacking. 911 o Removed the text speculation on adoption of the TSA message. 913 o Clarified that the ND protocol is used. 915 o Clarified what it means "No association needed". 917 o Added some text about how two STAs discover each other. 919 o Added mention of external (OCB) and internal network (stable), in 920 the subnet structure section. 922 o Added phrase explaining that both .11 Data and .11 QoS Data 923 headers are currently being used, and may be used in the future. 925 o Moved the packet capture example into an Appendix Implementation 926 Status. 928 o Suggested moving the reliability requirements appendix out into 929 another document. 931 o Added a IANA Consiserations section, with content, requesting for 932 a new multicast group "all OCB interfaces". 934 o Added new OBU term, improved the RSU term definition, removed the 935 ETTC term, replaced more occurences of 802.11p, 802.11 OCB with 936 802.11-OCB. 938 o References: 940 * Added an informational reference to ETSI's IPv6-over- 941 GeoNetworking. 943 * Added more references to IETF and ETSI security protocols. 945 * Updated some references from I-D to RFC, and from old RFC to 946 new RFC numbers. 948 * Added reference to multicast extensions to IPsec architecture 949 RFC. 951 * Added a reference to 2464-bis. 953 * Removed FCC informative references, because not used. 955 o Updated the affiliation of one author. 957 o Reformulation of some phrases for better readability, and 958 correction of typographical errors. 960 From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave- 961 ipv6-over-80211ocb-04 963 o Removed a few informative references pointing to Dx draft IEEE 964 1609 documents. 966 o Removed outdated informative references to ETSI documents. 968 o Added citations to IEEE 1609.2, .3 and .4-2016. 970 o Minor textual issues. 972 From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave- 973 ipv6-over-80211ocb-03 975 o Keep the previous text on multiple addresses, so remove talk about 976 MIP6, NEMOv6 and MCoA. 978 o Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon. 980 o Clarified the figure showing Infrastructure mode and OCB mode side 981 by side. 983 o Added a reference to the IP Security Architecture RFC. 985 o Detailed the IPv6-per-channel prohibition paragraph which reflects 986 the discussion at the last IETF IPWAVE WG meeting. 988 o Added section "Address Mapping -- Unicast". 990 o Added the ".11 Trailer" to pictures of 802.11 frames. 992 o Added text about SNAP carrying the Ethertype. 994 o New RSU definition allowing for it be both a Router and not 995 necessarily a Router some times. 997 o Minor textual issues. 999 From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave- 1000 ipv6-over-80211ocb-02 1002 o Replaced almost all occurences of 802.11p with 802.11-OCB, leaving 1003 only when explanation of evolution was necessary. 1005 o Shortened by removing parameter details from a paragraph in the 1006 Introduction. 1008 o Moved a reference from Normative to Informative. 1010 o Added text in intro clarifying there is no handover spec at IEEE, 1011 and that 1609.2 does provide security services. 1013 o Named the contents the fields of the EthernetII header (including 1014 the Ethertype bitstring). 1016 o Improved relationship between two paragraphs describing the 1017 increase of the Sequence Number in 802.11 header upon IP 1018 fragmentation. 1020 o Added brief clarification of "tracking". 1022 From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave- 1023 ipv6-over-80211ocb-01 1025 o Introduced message exchange diagram illustrating differences 1026 between 802.11 and 802.11 in OCB mode. 1028 o Introduced an appendix listing for information the set of 802.11 1029 messages that may be transmitted in OCB mode. 1031 o Removed appendix sections "Privacy Requirements", "Authentication 1032 Requirements" and "Security Certificate Generation". 1034 o Removed appendix section "Non IP Communications". 1036 o Introductory phrase in the Security Considerations section. 1038 o Improved the definition of "OCB". 1040 o Introduced theoretical stacked layers about IPv6 and IEEE layers 1041 including EPD. 1043 o Removed the appendix describing the details of prohibiting IPv6 on 1044 certain channels relevant to 802.11-OCB. 1046 o Added a brief reference in the privacy text about a precise clause 1047 in IEEE 1609.3 and .4. 1049 o Clarified the definition of a Road Side Unit. 1051 o Removed the discussion about security of WSA (because is non-IP). 1053 o Removed mentioning of the GeoNetworking discussion. 1055 o Moved references to scientific articles to a separate 'overview' 1056 draft, and referred to it. 1058 Appendix B. 802.11p 1060 The term "802.11p" is an earlier definition. The behaviour of 1061 "802.11p" networks is rolled in the document IEEE Std 802.11-2016. 1062 In that document the term 802.11p disappears. Instead, each 802.11p 1063 feature is conditioned by the Management Information Base (MIB) 1064 attribute "OCBActivated". Whenever OCBActivated is set to true the 1065 IEEE Std 802.11 OCB state is activated. For example, an 802.11 1066 STAtion operating outside the context of a basic service set has the 1067 OCBActivated flag set. Such a station, when it has the flag set, 1068 uses a BSS identifier equal to ff:ff:ff:ff:ff:ff. 1070 Appendix C. Aspects introduced by the OCB mode to 802.11 1072 In the IEEE 802.11-OCB mode, all nodes in the wireless range can 1073 directly communicate with each other without involving authentication 1074 or association procedures. At link layer, it is necessary to set the 1075 same channel number (or frequency) on two stations that need to 1076 communicate with each other. The manner in which stations set their 1077 channel number is not specified in this document. Stations STA1 and 1078 STA2 can exchange IP packets if they are set on the same channel. At 1079 IP layer, they then discover each other by using the IPv6 Neighbor 1080 Discovery protocol. 1082 Briefly, the IEEE 802.11-OCB mode has the following properties: 1084 o The use by each node of a 'wildcard' BSSID (i.e., each bit of the 1085 BSSID is set to 1) 1087 o No IEEE 802.11 Beacon frames are transmitted 1089 o No authentication is required in order to be able to communicate 1090 o No association is needed in order to be able to communicate 1092 o No encryption is provided in order to be able to communicate 1094 o Flag dot11OCBActivated is set to true 1096 All the nodes in the radio communication range (IP-OBU and IP-RSU) 1097 receive all the messages transmitted (IP-OBU and IP-RSU) within the 1098 radio communications range. The eventual conflict(s) are resolved by 1099 the MAC CDMA function. 1101 The message exchange diagram in Figure 4 illustrates a comparison 1102 between traditional 802.11 and 802.11 in OCB mode. The 'Data' 1103 messages can be IP packets such as HTTP or others. Other 802.11 1104 management and control frames (non IP) may be transmitted, as 1105 specified in the 802.11 standard. For information, the names of 1106 these messages as currently specified by the 802.11 standard are 1107 listed in Appendix G. 1109 STA AP STA1 STA2 1110 | | | | 1111 |<------ Beacon -------| |<------ Data -------->| 1112 | | | | 1113 |---- Probe Req. ----->| |<------ Data -------->| 1114 |<--- Probe Res. ------| | | 1115 | | |<------ Data -------->| 1116 |---- Auth Req. ------>| | | 1117 |<--- Auth Res. -------| |<------ Data -------->| 1118 | | | | 1119 |---- Asso Req. ------>| |<------ Data -------->| 1120 |<--- Asso Res. -------| | | 1121 | | |<------ Data -------->| 1122 |<------ Data -------->| | | 1123 |<------ Data -------->| |<------ Data -------->| 1125 (i) 802.11 Infrastructure mode (ii) 802.11-OCB mode 1127 Figure 4: Difference between messages exchanged on 802.11 (left) and 1128 802.11-OCB (right) 1130 The interface 802.11-OCB was specified in IEEE Std 802.11p (TM) -2010 1131 [IEEE-802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, 1132 titled "Amendment 6: Wireless Access in Vehicular Environments". 1133 Since then, this amendment has been integrated in IEEE 802.11(TM) 1134 -2012 and -2016 [IEEE-802.11-2016]. 1136 In document 802.11-2016, anything qualified specifically as 1137 "OCBActivated", or "outside the context of a basic service" set to be 1138 true, then it is actually referring to OCB aspects introduced to 1139 802.11. 1141 In order to delineate the aspects introduced by 802.11-OCB to 802.11, 1142 we refer to the earlier [IEEE-802.11p-2010]. The amendment is 1143 concerned with vehicular communications, where the wireless link is 1144 similar to that of Wireless LAN (using a PHY layer specified by 1145 802.11a/b/g/n), but which needs to cope with the high mobility factor 1146 inherent in scenarios of communications between moving vehicles, and 1147 between vehicles and fixed infrastructure deployed along roads. 1148 While 'p' is a letter identifying the Ammendment, just like 'a, b, g' 1149 and 'n' are, 'p' is concerned more with MAC modifications, and a 1150 little with PHY modifications; the others are mainly about PHY 1151 modifications. It is possible in practice to combine a 'p' MAC with 1152 an 'a' PHY by operating outside the context of a BSS with OFDM at 1153 5.4GHz and 5.9GHz. 1155 The 802.11-OCB links are specified to be compatible as much as 1156 possible with the behaviour of 802.11a/b/g/n and future generation 1157 IEEE WLAN links. From the IP perspective, an 802.11-OCB MAC layer 1158 offers practically the same interface to IP as the 802.11a/b/g/n and 1159 802.3. A packet sent by an IP-OBU may be received by one or multiple 1160 IP-RSUs. The link-layer resolution is performed by using the IPv6 1161 Neighbor Discovery protocol. 1163 To support this similarity statement (IPv6 is layered on top of LLC 1164 on top of 802.11-OCB, in the same way that IPv6 is layered on top of 1165 LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on 1166 top of 802.3 (for Ethernet)) it is useful to analyze the differences 1167 between 802.11-OCB and 802.11 specifications. During this analysis, 1168 we note that whereas 802.11-OCB lists relatively complex and numerous 1169 changes to the MAC layer (and very little to the PHY layer), there 1170 are only a few characteristics which may be important for an 1171 implementation transmitting IPv6 packets on 802.11-OCB links. 1173 The most important 802.11-OCB point which influences the IPv6 1174 functioning is the OCB characteristic; an additional, less direct 1175 influence, is the maximum bandwidth afforded by the PHY modulation/ 1176 demodulation methods and channel access specified by 802.11-OCB. The 1177 maximum bandwidth theoretically possible in 802.11-OCB is 54 Mbit/s 1178 (when using, for example, the following parameters: 20 MHz channel; 1179 modulation 64-QAM; coding rate R is 3/4); in practice of IP-over- 1180 802.11-OCB a commonly observed figure is 12Mbit/s; this bandwidth 1181 allows the operation of a wide range of protocols relying on IPv6. 1183 o Operation Outside the Context of a BSS (OCB): the (earlier 1184 802.11p) 802.11-OCB links are operated without a Basic Service Set 1185 (BSS). This means that the frames IEEE 802.11 Beacon, Association 1186 Request/Response, Authentication Request/Response, and similar, 1187 are not used. The used identifier of BSS (BSSID) has a 1188 hexadecimal value always 0xffffffffffff (48 '1' bits, represented 1189 as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' 1190 BSSID), as opposed to an arbitrary BSSID value set by 1191 administrator (e.g. 'My-Home-AccessPoint'). The OCB operation - 1192 namely the lack of beacon-based scanning and lack of 1193 authentication - should be taken into account when the Mobile IPv6 1194 protocol [RFC6275] and the protocols for IP layer security 1195 [RFC4301] are used. The way these protocols adapt to OCB is not 1196 described in this document. 1198 o Timing Advertisement: is a new message defined in 802.11-OCB, 1199 which does not exist in 802.11a/b/g/n. This message is used by 1200 stations to inform other stations about the value of time. It is 1201 similar to the time as delivered by a GNSS system (Galileo, GPS, 1202 ...) or by a cellular system. This message is optional for 1203 implementation. 1205 o Frequency range: this is a characteristic of the PHY layer, with 1206 almost no impact on the interface between MAC and IP. However, it 1207 is worth considering that the frequency range is regulated by a 1208 regional authority (ARCEP, ECC/CEPT based on ENs from ETSI, FCC, 1209 etc.); as part of the regulation process, specific applications 1210 are associated with specific frequency ranges. In the case of 1211 802.11-OCB, the regulator associates a set of frequency ranges, or 1212 slots within a band, to the use of applications of vehicular 1213 communications, in a band known as "5.9GHz". The 5.9GHz band is 1214 different from the 2.4GHz and 5GHz bands used by Wireless LAN. 1215 However, as with Wireless LAN, the operation of 802.11-OCB in 1216 "5.9GHz" bands is exempt from owning a license in EU (in US the 1217 5.9GHz is a licensed band of spectrum; for the fixed 1218 infrastructure an explicit FCC authorization is required; for an 1219 on-board device a 'licensed-by-rule' concept applies: rule 1220 certification conformity is required.) Technical conditions are 1221 different than those of the bands "2.4GHz" or "5GHz". The allowed 1222 power levels, and implicitly the maximum allowed distance between 1223 vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20 1224 dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum 1225 distance of approximately 1km, compared to approximately 50m. 1226 Additionally, specific conditions related to congestion avoidance, 1227 jamming avoidance, and radar detection are imposed on the use of 1228 DSRC (in US) and on the use of frequencies for Intelligent 1229 Transportation Systems (in EU), compared to Wireless LAN 1230 (802.11a/b/g/n). 1232 o 'Half-rate' encoding: as the frequency range, this parameter is 1233 related to PHY, and thus has not much impact on the interface 1234 between the IP layer and the MAC layer. 1236 o In vehicular communications using 802.11-OCB links, there are 1237 strong privacy requirements with respect to addressing. While the 1238 802.11-OCB standard does not specify anything in particular with 1239 respect to MAC addresses, in these settings there exists a strong 1240 need for dynamic change of these addresses (as opposed to the non- 1241 vehicular settings - real wall protection - where fixed MAC 1242 addresses do not currently pose some privacy risks). This is 1243 further described in Section 5. A relevant function is described 1244 in IEEE 1609.3-2016 [IEEE-1609.3], clause 5.5.1 and IEEE 1245 1609.4-2016 [IEEE-1609.4], clause 6.7. 1247 Other aspects particular to 802.11-OCB, which are also particular to 1248 802.11 (e.g. the 'hidden node' operation), may have an influence on 1249 the use of transmission of IPv6 packets on 802.11-OCB networks. The 1250 OCB subnet structure is described in Section 4.6. 1252 Appendix D. Changes Needed on a software driver 802.11a to become a 1253 802.11-OCB driver 1255 The 802.11p amendment modifies both the 802.11 stack's physical and 1256 MAC layers but all the induced modifications can be quite easily 1257 obtained by modifying an existing 802.11a ad-hoc stack. 1259 Conditions for a 802.11a hardware to be 802.11-OCB compliant: 1261 o The PHY entity shall be an orthogonal frequency division 1262 multiplexing (OFDM) system. It must support the frequency bands 1263 on which the regulator recommends the use of ITS communications, 1264 for example using IEEE 802.11-OCB layer, in France: 5875MHz to 1265 5925MHz. 1267 o The OFDM system must provide a "half-clocked" operation using 10 1268 MHz channel spacings. 1270 o The chip transmit spectrum mask must be compliant to the "Transmit 1271 spectrum mask" from the IEEE 802.11p amendment (but experimental 1272 environments tolerate otherwise). 1274 o The chip should be able to transmit up to 44.8 dBm when used by 1275 the US government in the United States, and up to 33 dBm in 1276 Europe; other regional conditions apply. 1278 Changes needed on the network stack in OCB mode: 1280 o Physical layer: 1282 * The chip must use the Orthogonal Frequency Multiple Access 1283 (OFDM) encoding mode. 1285 * The chip must be set in half-mode rate mode (the internal clock 1286 frequency is divided by two). 1288 * The chip must use dedicated channels and should allow the use 1289 of higher emission powers. This may require modifications to 1290 the local computer file that describes regulatory domains 1291 rules, if used by the kernel to enforce local specific 1292 restrictions. Such modifications to the local computer file 1293 must respect the location-specific regulatory rules. 1295 MAC layer: 1297 * All management frames (beacons, join, leave, and others) 1298 emission and reception must be disabled except for frames of 1299 subtype Action and Timing Advertisement (defined below). 1301 * No encryption key or method must be used. 1303 * Packet emission and reception must be performed as in ad-hoc 1304 mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff). 1306 * The functions related to joining a BSS (Association Request/ 1307 Response) and for authentication (Authentication Request/Reply, 1308 Challenge) are not called. 1310 * The beacon interval is always set to 0 (zero). 1312 * Timing Advertisement frames, defined in the amendment, should 1313 be supported. The upper layer should be able to trigger such 1314 frames emission and to retrieve information contained in 1315 received Timing Advertisements. 1317 Appendix E. EtherType Protocol Discrimination (EPD) 1319 A more theoretical and detailed view of layer stacking, and 1320 interfaces between the IP layer and 802.11-OCB layers, is illustrated 1321 in Figure 5. The IP layer operates on top of the EtherType Protocol 1322 Discrimination (EPD); this Discrimination layer is described in IEEE 1323 Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP 1324 (Link Layer Control Service Access Point). 1326 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1327 | IPv6 | 1328 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ 1329 { LLC_SAP } 802.11-OCB 1330 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary 1331 | EPD | | | 1332 | | MLME | | 1333 +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | 1334 | MAC Sublayer | | | 802.11-OCB 1335 | and ch. coord. | | SME | Services 1336 +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | 1337 | | PLME | | 1338 | PHY Layer | PLME_SAP | 1339 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1341 Figure 5: EtherType Protocol Discrimination 1343 Appendix F. Design Considerations 1345 The networks defined by 802.11-OCB are in many ways similar to other 1346 networks of the 802.11 family. In theory, the encapsulation of IPv6 1347 over 802.11-OCB could be very similar to the operation of IPv6 over 1348 other networks of the 802.11 family. However, the high mobility, 1349 strong link asymmetry and very short connection makes the 802.11-OCB 1350 link significantly different from other 802.11 networks. Also, the 1351 automotive applications have specific requirements for reliability, 1352 security and privacy, which further add to the particularity of the 1353 802.11-OCB link. 1355 F.1. Vehicle ID 1357 In automotive networks it is required that each node is represented 1358 uniquely at a certain point in time. Accordingly, a vehicle must be 1359 identified by at least one unique identifier. The current 1360 specification at ETSI and at IEEE 1609 identifies a vehicle by its 1361 MAC address, which is obtained from the 802.11-OCB Network Interface 1362 Card (NIC). 1364 In case multiple 802.11-OCB NICs are present in one car, implicitely 1365 multiple vehicle IDs will be generated. Additionally, some software 1366 generates a random MAC address each time the computer boots; this 1367 constitutes an additional difficulty. 1369 A mechanim to uniquely identify a vehicle irrespectively to the 1370 multiplicity of NICs, or frequent MAC address generation, is 1371 necessary. 1373 F.2. Reliability Requirements 1375 The dynamically changing topology, short connectivity, mobile 1376 transmitter and receivers, different antenna heights, and many-to- 1377 many communication types, make IEEE 802.11-OCB links significantly 1378 different from other IEEE 802.11 links. Any IPv6 mechanism operating 1379 on IEEE 802.11-OCB link must support strong link asymmetry, spatio- 1380 temporal link quality, fast address resolution and transmission. 1382 IEEE 802.11-OCB strongly differs from other 802.11 systems to operate 1383 outside of the context of a Basic Service Set. This means in 1384 practice that IEEE 802.11-OCB does not rely on a Base Station for all 1385 Basic Service Set management. In particular, IEEE 802.11-OCB shall 1386 not use beacons. Any IPv6 mechanism requiring L2 services from IEEE 1387 802.11 beacons must support an alternative service. 1389 Channel scanning being disabled, IPv6 over IEEE 802.11-OCB must 1390 implement a mechanism for transmitter and receiver to converge to a 1391 common channel. 1393 Authentication not being possible, IPv6 over IEEE 802.11-OCB must 1394 implement an distributed mechanism to authenticate transmitters and 1395 receivers without the support of a DHCP server. 1397 Time synchronization not being available, IPv6 over IEEE 802.11-OCB 1398 must implement a higher layer mechanism for time synchronization 1399 between transmitters and receivers without the support of a NTP 1400 server. 1402 The IEEE 802.11-OCB link being asymmetric, IPv6 over IEEE 802.11-OCB 1403 must disable management mechanisms requesting acknowledgements or 1404 replies. 1406 The IEEE 802.11-OCB link having a short duration time, IPv6 over IEEE 1407 802.11-OCB should implement fast IPv6 mobility management mechanisms. 1409 F.3. Multiple interfaces 1411 There are considerations for 2 or more IEEE 802.11-OCB interface 1412 cards per vehicle. For each vehicle taking part in road traffic, one 1413 IEEE 802.11-OCB interface card could be fully allocated for Non IP 1414 safety-critical communication. Any other IEEE 802.11-OCB may be used 1415 for other type of traffic. 1417 The mode of operation of these other wireless interfaces is not 1418 clearly defined yet. One possibility is to consider each card as an 1419 independent network interface, with a specific MAC Address and a set 1420 of IPv6 addresses. Another possibility is to consider the set of 1421 these wireless interfaces as a single network interface (not 1422 including the IEEE 802.11-OCB interface used by Non IP safety 1423 critical communications). This will require specific logic to 1424 ensure, for example, that packets meant for a vehicle in front are 1425 actually sent by the radio in the front, or that multiple copies of 1426 the same packet received by multiple interfaces are treated as a 1427 single packet. Treating each wireless interface as a separate 1428 network interface pushes such issues to the application layer. 1430 Certain privacy requirements imply that if these multiple interfaces 1431 are represented by many network interface, a single renumbering event 1432 shall cause renumbering of all these interfaces. If one MAC changed 1433 and another stayed constant, external observers would be able to 1434 correlate old and new values, and the privacy benefits of 1435 randomization would be lost. 1437 The privacy requirements of Non IP safety-critical communications 1438 imply that if a change of pseudonyme occurs, renumbering of all other 1439 interfaces shall also occur. 1441 F.4. MAC Address Generation 1443 In 802.11-OCB networks, the MAC addresses may change during well 1444 defined renumbering events. A 'randomized' MAC address has the 1445 following characteristics: 1447 o Bit "Local/Global" set to "locally admninistered". 1449 o Bit "Unicast/Multicast" set to "Unicast". 1451 o The 46 remaining bits are set to a random value, using a random 1452 number generator that meets the requirements of [RFC4086]. 1454 To meet the randomization requirements for the 46 remaining bits, a 1455 hash function may be used. For example, the SHA256 hash function may 1456 be used with input a 256 bit local secret, the "nominal" MAC Address 1457 of the interface, and a representation of the date and time of the 1458 renumbering event. 1460 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode 1462 For information, at the time of writing, this is the list of IEEE 1463 802.11 messages that may be transmitted in OCB mode, i.e. when 1464 dot11OCBActivated is true in a STA: 1466 o The STA may send management frames of subtype Action and, if the 1467 STA maintains a TSF Timer, subtype Timing Advertisement; 1469 o The STA may send control frames, except those of subtype PS-Poll, 1470 CF-End, and CF-End plus CFAck; 1472 o The STA may send data frames of subtype Data, Null, QoS Data, and 1473 QoS Null. 1475 Appendix H. Implementation Status 1477 This section describes an example of an IPv6 Packet captured over a 1478 IEEE 802.11-OCB link. 1480 By way of example we show that there is no modification in the 1481 headers when transmitted over 802.11-OCB networks - they are 1482 transmitted like any other 802.11 and Ethernet packets. 1484 We describe an experiment of capturing an IPv6 packet on an 1485 802.11-OCB link. In topology depicted in Figure 6, the packet is an 1486 IPv6 Router Advertisement. This packet is emitted by a Router on its 1487 802.11-OCB interface. The packet is captured on the Host, using a 1488 network protocol analyzer (e.g. Wireshark); the capture is performed 1489 in two different modes: direct mode and 'monitor' mode. The topology 1490 used during the capture is depicted below. 1492 The packet is captured on the Host. The Host is an IP-OBU containing 1493 an 802.11 interface in format PCI express (an ITRI product). The 1494 kernel runs the ath5k software driver with modifications for OCB 1495 mode. The capture tool is Wireshark. The file format for save and 1496 analyze is 'pcap'. The packet is generated by the Router. The 1497 Router is an IP-RSU (ITRI product). 1499 +--------+ +-------+ 1500 | | 802.11-OCB Link | | 1501 ---| Router |--------------------------------| Host | 1502 | | | | 1503 +--------+ +-------+ 1505 Figure 6: Topology for capturing IP packets on 802.11-OCB 1507 During several capture operations running from a few moments to 1508 several hours, no message relevant to the BSSID contexts were 1509 captured (no Association Request/Response, Authentication Req/Resp, 1510 Beacon). This shows that the operation of 802.11-OCB is outside the 1511 context of a BSSID. 1513 Overall, the captured message is identical with a capture of an IPv6 1514 packet emitted on a 802.11b interface. The contents are precisely 1515 similar. 1517 H.1. Capture in Monitor Mode 1519 The IPv6 RA packet captured in monitor mode is illustrated below. 1520 The radio tap header provides more flexibility for reporting the 1521 characteristics of frames. The Radiotap Header is prepended by this 1522 particular stack and operating system on the Host machine to the RA 1523 packet received from the network (the Radiotap Header is not present 1524 on the air). The implementation-dependent Radiotap Header is useful 1525 for piggybacking PHY information from the chip's registers as data in 1526 a packet understandable by userland applications using Socket 1527 interfaces (the PHY interface can be, for example: power levels, data 1528 rate, ratio of signal to noise). 1530 The packet present on the air is formed by IEEE 802.11 Data Header, 1531 Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. 1533 Radiotap Header v0 1534 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1535 |Header Revision| Header Pad | Header length | 1536 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1537 | Present flags | 1538 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1539 | Data Rate | Pad | 1540 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1542 IEEE 802.11 Data Header 1543 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1544 | Type/Subtype and Frame Ctrl | Duration | 1545 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1546 | Receiver Address... 1547 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1548 ... Receiver Address | Transmitter Address... 1549 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1550 ... Transmitter Address | 1551 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1552 | BSS Id... 1553 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1554 ... BSS Id | Frag Number and Seq Number | 1555 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1557 Logical-Link Control Header 1558 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1559 | DSAP |I| SSAP |C| Control field | Org. code... 1560 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1561 ... Organizational Code | Type | 1562 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1564 IPv6 Base Header 1565 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1566 |Version| Traffic Class | Flow Label | 1567 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1568 | Payload Length | Next Header | Hop Limit | 1569 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1570 | | 1571 + + 1572 | | 1573 + Source Address + 1574 | | 1575 + + 1576 | | 1577 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1578 | | 1579 + + 1580 | | 1581 + Destination Address + 1582 | | 1583 + + 1584 | | 1585 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1587 Router Advertisement 1588 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1589 | Type | Code | Checksum | 1590 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1591 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1592 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1593 | Reachable Time | 1594 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1595 | Retrans Timer | 1596 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1597 | Options ... 1598 +-+-+-+-+-+-+-+-+-+-+-+- 1600 The value of the Data Rate field in the Radiotap header is set to 6 1601 Mb/s. This indicates the rate at which this RA was received. 1603 The value of the Transmitter address in the IEEE 802.11 Data Header 1604 is set to a 48bit value. The value of the destination address is 1605 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS 1606 Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network 1607 protocol analyzer as being "broadcast". The Fragment number and 1608 sequence number fields are together set to 0x90C6. 1610 The value of the Organization Code field in the Logical-Link Control 1611 Header is set to 0x0, recognized as "Encapsulated Ethernet". The 1612 value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise 1613 #86DD), recognized as "IPv6". 1615 A Router Advertisement is periodically sent by the router to 1616 multicast group address ff02::1. It is an icmp packet type 134. The 1617 IPv6 Neighbor Discovery's Router Advertisement message contains an 1618 8-bit field reserved for single-bit flags, as described in [RFC4861]. 1620 The IPv6 header contains the link local address of the router 1621 (source) configured via EUI-64 algorithm, and destination address set 1622 to ff02::1. Recent versions of network protocol analyzers (e.g. 1623 Wireshark) provide additional informations for an IP address, if a 1624 geolocalization database is present. In this example, the 1625 geolocalization database is absent, and the "GeoIP" information is 1626 set to unknown for both source and destination addresses (although 1627 the IPv6 source and destination addresses are set to useful values). 1628 This "GeoIP" can be a useful information to look up the city, 1629 country, AS number, and other information for an IP address. 1631 The Ethernet Type field in the logical-link control header is set to 1632 0x86dd which indicates that the frame transports an IPv6 packet. In 1633 the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 1634 which is the corresponding multicast MAC address. The BSS id is a 1635 broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link 1636 duration between vehicles and the roadside infrastructure, there is 1637 no need in IEEE 802.11-OCB to wait for the completion of association 1638 and authentication procedures before exchanging data. IEEE 1639 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) 1640 and may start communicating as soon as they arrive on the 1641 communication channel. 1643 H.2. Capture in Normal Mode 1645 The same IPv6 Router Advertisement packet described above (monitor 1646 mode) is captured on the Host, in the Normal mode, and depicted 1647 below. 1649 Ethernet II Header 1650 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1651 | Destination... 1652 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1653 ...Destination | Source... 1654 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1655 ...Source | 1656 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1657 | Type | 1658 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1660 IPv6 Base Header 1661 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1662 |Version| Traffic Class | Flow Label | 1663 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1664 | Payload Length | Next Header | Hop Limit | 1665 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1666 | | 1667 + + 1668 | | 1669 + Source Address + 1670 | | 1671 + + 1672 | | 1673 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1674 | | 1675 + + 1676 | | 1677 + Destination Address + 1678 | | 1679 + + 1680 | | 1681 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1683 Router Advertisement 1684 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1685 | Type | Code | Checksum | 1686 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1687 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1688 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1689 | Reachable Time | 1690 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1691 | Retrans Timer | 1692 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1693 | Options ... 1694 +-+-+-+-+-+-+-+-+-+-+-+- 1696 One notices that the Radiotap Header, the IEEE 802.11 Data Header and 1697 the Logical-Link Control Headers are not present. On the other hand, 1698 a new header named Ethernet II Header is present. 1700 The Destination and Source addresses in the Ethernet II header 1701 contain the same values as the fields Receiver Address and 1702 Transmitter Address present in the IEEE 802.11 Data Header in the 1703 "monitor" mode capture. 1705 The value of the Type field in the Ethernet II header is 0x86DD 1706 (recognized as "IPv6"); this value is the same value as the value of 1707 the field Type in the Logical-Link Control Header in the "monitor" 1708 mode capture. 1710 The knowledgeable experimenter will no doubt notice the similarity of 1711 this Ethernet II Header with a capture in normal mode on a pure 1712 Ethernet cable interface. 1714 An Adaptation layer is inserted on top of a pure IEEE 802.11 MAC 1715 layer, in order to adapt packets, before delivering the payload data 1716 to the applications. It adapts 802.11 LLC/MAC headers to Ethernet II 1717 headers. In further detail, this adaptation consists in the 1718 elimination of the Radiotap, 802.11 and LLC headers, and in the 1719 insertion of the Ethernet II header. In this way, IPv6 runs straight 1720 over LLC over the 802.11-OCB MAC layer; this is further confirmed by 1721 the use of the unique Type 0x86DD. 1723 Appendix I. Extra Terminology 1725 The following terms are defined outside the IETF. They are used to 1726 define the main terms in the main terminology section Section 2. 1728 DSRC (Dedicated Short Range Communication): a term defined outside 1729 the IETF. The US Federal Communications Commission (FCC) Dedicated 1730 Short Range Communication (DSRC) is defined in the Code of Federal 1731 Regulations (CFR) 47, Parts 90 and 95. This Code is referred in the 1732 definitions below. At the time of the writing of this Internet 1733 Draft, the last update of this Code was dated October 1st, 2010. 1735 DSRCS (Dedicated Short-Range Communications Services): a term defined 1736 outside the IETF. The use of radio techniques to transfer data over 1737 short distances between roadside and mobile units, between mobile 1738 units, and between portable and mobile units to perform operations 1739 related to the improvement of traffic flow, traffic safety, and other 1740 intelligent transportation service applications in a variety of 1741 environments. DSRCS systems may also transmit status and 1742 instructional messages related to the units involve. [Ref. 47 CFR 1743 90.7 - Definitions] 1744 OBU (On-Board Unit): a term defined outside the IETF. An On-Board 1745 Unit is a DSRCS transceiver that is normally mounted in or on a 1746 vehicle, or which in some instances may be a portable unit. An OBU 1747 can be operational while a vehicle or person is either mobile or 1748 stationary. The OBUs receive and contend for time to transmit on one 1749 or more radio frequency (RF) channels. Except where specifically 1750 excluded, OBU operation is permitted wherever vehicle operation or 1751 human passage is permitted. The OBUs mounted in vehicles are 1752 licensed by rule under part 95 of the respective chapter and 1753 communicate with Roadside Units (RSUs) and other OBUs. Portable OBUs 1754 are also licensed by rule under part 95 of the respective chapter. 1755 OBU operations in the Unlicensed National Information Infrastructure 1756 (UNII) Bands follow the rules in those bands. - [CFR 90.7 - 1757 Definitions]. 1759 RSU (Road-Side Unit): a term defined outside of IETF. A Roadside 1760 Unit is a DSRC transceiver that is mounted along a road or pedestrian 1761 passageway. An RSU may also be mounted on a vehicle or is hand 1762 carried, but it may only operate when the vehicle or hand- carried 1763 unit is stationary. Furthermore, an RSU operating under the 1764 respectgive part is restricted to the location where it is licensed 1765 to operate. However, portable or hand-held RSUs are permitted to 1766 operate where they do not interfere with a site-licensed operation. 1767 A RSU broadcasts data to OBUs or exchanges data with OBUs in its 1768 communications zone. An RSU also provides channel assignments and 1769 operating instructions to OBUs in its communications zone, when 1770 required. - [CFR 90.7 - Definitions]. 1772 Authors' Addresses 1774 Alexandre Petrescu 1775 CEA, LIST 1776 CEA Saclay 1777 Gif-sur-Yvette , Ile-de-France 91190 1778 France 1780 Phone: +33169089223 1781 Email: Alexandre.Petrescu@cea.fr 1783 Nabil Benamar 1784 Moulay Ismail University 1785 Morocco 1787 Phone: +212670832236 1788 Email: n.benamar@est.umi.ac.ma 1789 Jerome Haerri 1790 Eurecom 1791 Sophia-Antipolis 06904 1792 France 1794 Phone: +33493008134 1795 Email: Jerome.Haerri@eurecom.fr 1797 Jong-Hyouk Lee 1798 Sangmyung University 1799 31, Sangmyeongdae-gil, Dongnam-gu 1800 Cheonan 31066 1801 Republic of Korea 1803 Email: jonghyouk@smu.ac.kr 1805 Thierry Ernst 1806 YoGoKo 1807 France 1809 Email: thierry.ernst@yogoko.fr