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Found 'MAY NOT' in this paragraph: -31: filled in the section titled "Pseudonym Handling"; removed a 'MAY NOT' phrase about possibility of having other prefix than the LL on the link between cars; shortened and improved the paragraph about Mobile IPv6, now with DNAv6; improved the ND text about ND retransmissions with relationship to packet loss; changed the title of an appendix from 'EPD' to 'Protocol Layering'; improved the 'Aspects introduced by OCB' appendix with a few phrases about the channel use and references. -- The document date (April 17, 2019) is 1837 days in the past. 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. 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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IPWAVE Working Group A. Petrescu 3 Internet-Draft CEA, LIST 4 Intended status: Standards Track N. Benamar 5 Expires: October 19, 2019 Moulay Ismail University 6 J. Haerri 7 Eurecom 8 J. Lee 9 Sangmyung University 10 T. Ernst 11 YoGoKo 12 April 17, 2019 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-42 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 October 19, 2019. 47 Copyright Notice 49 Copyright (c) 2019 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 . . . . . . . . . . . . . . . . . . . . 4 68 4.1. Maximum Transmission Unit (MTU) . . . . . . . . . . . . . 4 69 4.2. Frame Format . . . . . . . . . . . . . . . . . . . . . . 5 70 4.2.1. Ethernet Adaptation Layer . . . . . . . . . . . . . . 5 71 4.3. Link-Local Addresses . . . . . . . . . . . . . . . . . . 7 72 4.4. Stateless Autoconfiguration . . . . . . . . . . . . . . . 7 73 4.5. Address Mapping . . . . . . . . . . . . . . . . . . . . . 8 74 4.5.1. Address Mapping -- Unicast . . . . . . . . . . . . . 8 75 4.5.2. Address Mapping -- Multicast . . . . . . . . . . . . 8 76 4.6. Subnet Structure . . . . . . . . . . . . . . . . . . . . 8 77 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9 78 5.1. Privacy Considerations . . . . . . . . . . . . . . . . . 10 79 5.1.1. Privacy Risks of Meaningful info in Interface IDs . . 10 80 5.2. MAC Address and Interface ID Generation . . . . . . . . . 11 81 5.3. Pseudonym Handling . . . . . . . . . . . . . . . . . . . 11 82 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 83 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 12 84 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 85 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 86 9.1. Normative References . . . . . . . . . . . . . . . . . . 13 87 9.2. Informative References . . . . . . . . . . . . . . . . . 15 88 Appendix A. ChangeLog . . . . . . . . . . . . . . . . . . . . . 17 89 Appendix B. 802.11p . . . . . . . . . . . . . . . . . . . . . . 28 90 Appendix C. Aspects introduced by the OCB mode to 802.11 . . . . 28 91 Appendix D. Changes Needed on a software driver 802.11a to 92 become a 802.11-OCB driver . . . 32 93 Appendix E. Protocol Layering . . . . . . . . . . . . . . . . . 33 94 Appendix F. Design Considerations . . . . . . . . . . . . . . . 34 95 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode . . . . 34 96 Appendix H. Examples of Packet Formats . . . . . . . . . . . . . 35 97 H.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . 36 98 H.2. Capture in Normal Mode . . . . . . . . . . . . . . . . . 38 99 Appendix I. Extra Terminology . . . . . . . . . . . . . . . . . 40 100 Appendix J. Neighbor Discovery (ND) Potential Issues in Wireless 101 Links . . . . . . . . . . . . . . . . . . . . . . . 41 102 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 43 104 1. Introduction 106 This document describes the transmission of IPv6 packets on IEEE Std 107 802.11-OCB networks [IEEE-802.11-2016] (a.k.a "802.11p" see 108 Appendix B, Appendix C and Appendix D). This involves the layering 109 of IPv6 networking on top of the IEEE 802.11 MAC layer, with an LLC 110 layer. Compared to running IPv6 over the Ethernet MAC layer, there 111 is no modification expected to IEEE Std 802.11 MAC and Logical Link 112 sublayers: IPv6 works fine directly over 802.11-OCB too, with an LLC 113 layer. 115 The IPv6 network layer operates on 802.11-OCB in the same manner as 116 operating on Ethernet, but there are two kinds of exceptions: 118 o Exceptions due to different operation of IPv6 network layer on 119 802.11 than on Ethernet. To satisfy these exceptions, this 120 document describes an Ethernet Adaptation Layer between Ethernet 121 headers and 802.11 headers. The Ethernet Adaptation Layer is 122 described Section 4.2.1. The operation of IP on Ethernet is 123 described in [RFC1042], [RFC2464] . 125 o Exceptions due to the OCB nature of 802.11-OCB compared to 802.11. 126 This has impacts on security, privacy, subnet structure and 127 movement detection. For security and privacy recommendations see 128 Section 5 and Section 4.4. The subnet structure is described in 129 Section 4.6. The movement detection on OCB links is not described 130 in this document. 132 In the published literature, many documents describe aspects and 133 problems related to running IPv6 over 802.11-OCB: 134 [I-D.ietf-ipwave-vehicular-networking]. 136 2. Terminology 138 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 139 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 140 "OPTIONAL" in this document are to be interpreted as described in BCP 141 14 [RFC2119] [RFC8174] when, and only when, they appear in all 142 capitals, as shown here. 144 IP-OBU (Internet Protocol On-Board Unit): an IP-OBU is a computer 145 situated in a vehicle such as an automobile, bicycle, or similar. It 146 has at least one IP interface that runs in mode OCB of 802.11, and 147 that has an "OBU" transceiver. See the definition of the term "OBU" 148 in section Appendix I. 150 IP-RSU (IP Road-Side Unit): an IP-RSU is situated along the road. It 151 has at least two distinct IP-enabled interfaces; the wireless PHY/MAC 152 layer of at least one of its IP-enabled interfaces is configured to 153 operate in 802.11-OCB mode. An IP-RSU communicates with the IP-OBU 154 in the vehicle over 802.11 wireless link operating in OCB mode. An 155 IP-RSU is similar to an Access Network Router (ANR) defined in 156 [RFC3753], and a Wireless Termination Point (WTP) defined in 157 [RFC5415]. 159 OCB (outside the context of a basic service set - BSS): A mode of 160 operation in which a STA is not a member of a BSS and does not 161 utilize IEEE Std 802.11 authentication, association, or data 162 confidentiality. 164 802.11-OCB: mode specified in IEEE Std 802.11-2016 when the MIB 165 attribute dot11OCBActivited is true. Note: compliance with standards 166 and regulations set in different countries when using the 5.9GHz 167 frequency band is required. 169 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 171 The IEEE 802.11-OCB Networks are used for vehicular communications, 172 as 'Wireless Access in Vehicular Environments'. The IP communication 173 scenarios for these environments have been described in several 174 documents; in particular, we refer the reader to 175 [I-D.ietf-ipwave-vehicular-networking], that lists some scenarios and 176 requirements for IP in Intelligent Transportation Systems. 178 The link model is the following: STA --- 802.11-OCB --- STA. In 179 vehicular networks, STAs can be IP-RSUs and/or IP-OBUs. While 180 802.11-OCB is clearly specified, and the use of IPv6 over such link 181 is not radically new, the operating environment (vehicular networks) 182 brings in new perspectives. 184 4. IPv6 over 802.11-OCB 186 4.1. Maximum Transmission Unit (MTU) 188 The default MTU for IP packets on 802.11-OCB MUST be 1500 octets. It 189 is the same value as IPv6 packets on Ethernet links, as specified in 190 [RFC2464]. This value of the MTU respects the recommendation that 191 every link on the Internet must have a minimum MTU of 1280 octets 192 (stated in [RFC8200], and the recommendations therein, especially 193 with respect to fragmentation). 195 4.2. Frame Format 197 IP packets MUST be transmitted over 802.11-OCB media as QoS Data 198 frames whose format is specified in IEEE 802.11(TM) -2016 199 [IEEE-802.11-2016]. 201 The IPv6 packet transmitted on 802.11-OCB MUST be immediately 202 preceded by a Logical Link Control (LLC) header and an 802.11 header. 203 In the LLC header, and in accordance with the EtherType Protocol 204 Discrimination (EPD, see Appendix E), the value of the Type field 205 MUST be set to 0x86DD (IPv6). In the 802.11 header, the value of the 206 Subtype sub-field in the Frame Control field MUST be set to 8 (i.e. 207 'QoS Data'); the value of the Traffic Identifier (TID) sub-field of 208 the QoS Control field of the 802.11 header MUST be set to binary 001 209 (i.e. User Priority 'Background', QoS Access Category 'AC_BK'). 211 To simplify the Application Programming Interface (API) between the 212 operating system and the 802.11-OCB media, device drivers MAY 213 implement an Ethernet Adaptation Layer that translates Ethernet II 214 frames to the 802.11 format and vice versa. An Ethernet Adaptation 215 Layer is described in Section 4.2.1. 217 4.2.1. Ethernet Adaptation Layer 219 An 'adaptation' layer is inserted between a MAC layer and the 220 Networking layer. This is used to transform some parameters between 221 their form expected by the IP stack and the form provided by the MAC 222 layer. 224 An Ethernet Adaptation Layer makes an 802.11 MAC look to IP 225 Networking layer as a more traditional Ethernet layer. At reception, 226 this layer takes as input the IEEE 802.11 header and the Logical-Link 227 Layer Control Header and produces an Ethernet II Header. At sending, 228 the reverse operation is performed. 230 The operation of the Ethernet Adaptation Layer is depicted by the 231 double arrow in Figure 1. 233 +------------------+------------+-------------+---------+-----------+ 234 | 802.11 header | LLC Header | IPv6 Header | Payload |.11 Trailer| 235 +------------------+------------+-------------+---------+-----------+ 236 \ / \ / 237 --------------------------- -------- 238 \---------------------------------------------/ 239 ^ 240 | 241 802.11-to-Ethernet Adaptation Layer 242 | 243 v 244 +---------------------+-------------+---------+ 245 | Ethernet II Header | IPv6 Header | Payload | 246 +---------------------+-------------+---------+ 248 Figure 1: Operation of the Ethernet Adaptation Layer 250 The Receiver and Transmitter Address fields in the 802.11 header MUST 251 contain the same values as the Destination and the Source Address 252 fields in the Ethernet II Header, respectively. The value of the 253 Type field in the LLC Header MUST be the same as the value of the 254 Type field in the Ethernet II Header. That value MUST be set to 255 0x86DD (IPv6). 257 The ".11 Trailer" contains solely a 4-byte Frame Check Sequence. 259 The placement of IPv6 networking layer on Ethernet Adaptation Layer 260 is illustrated in Figure 2. 262 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 263 | IPv6 | 264 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 265 | Ethernet Adaptation Layer | 266 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 267 | 802.11 MAC | 268 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 269 | 802.11 PHY | 270 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 272 Figure 2: Ethernet Adaptation Layer stacked with other layers 274 (in the above figure, a 802.11 profile is represented; this is used 275 also for 802.11-OCB profile.) 277 4.3. Link-Local Addresses 279 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 280 MAY be assigned to an 802.11-OCB interface. Among these types of 281 addresses only the IPv6 link-local addresses MAY be formed using an 282 EUI-64 identifier, in particular during transition time. 284 If the IPv6 link-local address is formed using an EUI-64 identifier, 285 then the mechanism of forming that address is the same mechanism as 286 used to form an IPv6 link-local address on Ethernet links. This 287 mechanism is described in section 5 of [RFC2464]. 289 4.4. Stateless Autoconfiguration 291 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 292 MAY be assigned to an 802.11-OCB interface. This section describes 293 the formation of Interface Identifiers for IPv6 addresses of type 294 'Global' or 'Unique Local'. For Interface Identifiers for IPv6 295 address of type 'Link-Local' see Section 4.3. 297 The Interface Identifier for an 802.11-OCB interface is formed using 298 the same rules as the Interface Identifier for an Ethernet interface; 299 the RECOMMENDED method for forming stable Interface Identifiers 300 (IIDs) is described in [RFC8064]. The method of forming IIDs 301 described in section 4 of [RFC2464] MAY be used during transition 302 time, in particular for IPv6 link-local addresses. 304 The bits in the Interface Identifier have no generic meaning and the 305 identifier should be treated as an opaque value. The bits 306 'Universal' and 'Group' in the identifier of an 802.11-OCB interface 307 are significant, as this is an IEEE link-layer address. The details 308 of this significance are described in [RFC7136]. 310 Semantically opaque Interface Identifiers, instead of meaningful 311 Interface Identifiers derived from a valid and meaningful MAC address 312 ([RFC2464], section 4), help avoid certain privacy risks (see the 313 risks mentioned in Section 5.1.1). If semantically opaque Interface 314 Identifiers are needed, they MAY be generated using the method for 315 generating semantically opaque Interface Identifiers with IPv6 316 Stateless Address Autoconfiguration given in [RFC7217]. Typically, 317 an opaque Interface Identifier is formed starting from identifiers 318 different than the MAC addresses, and from cryptographically strong 319 material. Thus, privacy sensitive information is absent from 320 Interface IDs, because it is impossible to calculate back the initial 321 value from which the Interface ID was first generated (intuitively, 322 it is as hard as mentally finding the square root of a number, and as 323 impossible as trying to use computers to identify quickly whether a 324 large number is prime). 326 Some applications that use IPv6 packets on 802.11-OCB links (among 327 other link types) may benefit from IPv6 addresses whose Interface 328 Identifiers don't change too often. It is RECOMMENDED to use the 329 mechanisms described in RFC 7217 to permit the use of Stable 330 Interface Identifiers that do not change within one subnet prefix. A 331 possible source for the Net-Iface Parameter is a virtual interface 332 name, or logical interface name, that is decided by a local 333 administrator. 335 4.5. Address Mapping 337 Unicast and multicast address mapping MUST follow the procedures 338 specified for Ethernet interfaces in sections 6 and 7 of [RFC2464]. 340 4.5.1. Address Mapping -- Unicast 342 The procedure for mapping IPv6 unicast addresses into Ethernet link- 343 layer addresses is described in [RFC4861]. 345 4.5.2. Address Mapping -- Multicast 347 The multicast address mapping is performed according to the method 348 specified in section 7 of [RFC2464]. The meaning of the value "3333" 349 mentioned in that section 7 of [RFC2464] is defined in section 2.3.1 350 of [RFC7042]. 352 Transmitting IPv6 packets to multicast destinations over 802.11 links 353 proved to have some performance issues 354 [I-D.ietf-mboned-ieee802-mcast-problems]. These issues may be 355 exacerbated in OCB mode. Solutions for these problems SHOULD 356 consider the OCB mode of operation. 358 4.6. Subnet Structure 360 A subnet is formed by the external 802.11-OCB interfaces of vehicles 361 that are in close range (not by their in-vehicle interfaces). A 362 Prefix List conceptual data structure ([RFC4861] section 5.1) is 363 maintained for each 802.11-OCB interface. 365 The structure of this subnet is ephemeral, in that it is strongly 366 influenced by the mobility of vehicles: the hidden terminal effects 367 appear; the 802.11 networks in OCB mode may be considered as 'ad-hoc' 368 networks with an addressing model as described in [RFC5889]. On 369 another hand, the structure of the internal subnets in each car is 370 relatively stable. 372 As recommended in [RFC5889], when the timing requirements are very 373 strict (e.g. fast drive through IP-RSU coverage), no on-link subnet 374 prefix should be configured on an 802.11-OCB interface. In such 375 cases, the exclusive use of IPv6 link-local addresses is RECOMMENDED. 377 Additionally, even if the timing requirements are not very strict 378 (e.g. the moving subnet formed by two following vehicles is stable, a 379 fixed IP-RSU is absent), the subnet is disconnected from the Internet 380 (a default route is absent), and the addressing peers are equally 381 qualified (impossible to determine that some vehicle owns and 382 distributes addresses to others) the use of link-local addresses is 383 RECOMMENDED. 385 The baseline Neighbor Discovery protocol (ND) [RFC4861] MUST be used 386 over 802.11-OCB links. Transmitting ND packets may prove to have 387 some performance issues. These issues may be exacerbated in OCB 388 mode. Solutions for these problems SHOULD consider the OCB mode of 389 operation. The best of current knowledge indicates the kinds of 390 issues that may arise with ND in OCB mode; they are described in 391 Appendix J. 393 Protocols like Mobile IPv6 [RFC6275] and DNAv6 [RFC6059], which 394 depend on timely movement detection, might need additional tuning 395 work to handle the lack of link-layer notifications during handover. 396 This is for further study. 398 5. Security Considerations 400 Any security mechanism at the IP layer or above that may be carried 401 out for the general case of IPv6 may also be carried out for IPv6 402 operating over 802.11-OCB. 404 The OCB operation is stripped off of all existing 802.11 link-layer 405 security mechanisms. There is no encryption applied below the 406 network layer running on 802.11-OCB. At application layer, the IEEE 407 1609.2 document [IEEE-1609.2] does provide security services for 408 certain applications to use; application-layer mechanisms are out-of- 409 scope of this document. On another hand, a security mechanism 410 provided at networking layer, such as IPsec [RFC4301], may provide 411 data security protection to a wider range of applications. 413 802.11-OCB does not provide any cryptographic protection, because it 414 operates outside the context of a BSS (no Association Request/ 415 Response, no Challenge messages). Any attacker can therefore just 416 sit in the near range of vehicles, sniff the network (just set the 417 interface card's frequency to the proper range) and perform attacks 418 without needing to physically break any wall. Such a link is less 419 protected than commonly used links (wired link or protected 802.11). 421 The potential attack vectors are: MAC address spoofing, IP address 422 and session hijacking, and privacy violation Section 5.1. 424 Within the IPsec Security Architecture [RFC4301], the IPsec AH and 425 ESP headers [RFC4302] and [RFC4303] respectively, its multicast 426 extensions [RFC5374], HTTPS [RFC2818] and SeND [RFC3971] protocols 427 can be used to protect communications. Further, the assistance of 428 proper Public Key Infrastructure (PKI) protocols [RFC4210] is 429 necessary to establish credentials. More IETF protocols are 430 available in the toolbox of the IP security protocol designer. 431 Certain ETSI protocols related to security protocols in Intelligent 432 Transportation Systems are described in [ETSI-sec-archi]. 434 5.1. Privacy Considerations 436 As with all Ethernet and 802.11 interface identifiers ([RFC7721]), 437 the identifier of an 802.11-OCB interface may involve privacy, MAC 438 address spoofing and IP address hijacking risks. A vehicle embarking 439 an IP-OBU whose egress interface is 802.11-OCB may expose itself to 440 eavesdropping and subsequent correlation of data; this may reveal 441 data considered private by the vehicle owner; there is a risk of 442 being tracked. In outdoors public environments, where vehicles 443 typically circulate, the privacy risks are more important than in 444 indoors settings. It is highly likely that attacker sniffers are 445 deployed along routes which listen for IEEE frames, including IP 446 packets, of vehicles passing by. For this reason, in the 802.11-OCB 447 deployments, there is a strong necessity to use protection tools such 448 as dynamically changing MAC addresses Section 5.2, semantically 449 opaque Interface Identifiers and stable Interface Identifiers 450 Section 4.4. This may help mitigate privacy risks to a certain 451 level. 453 5.1.1. Privacy Risks of Meaningful info in Interface IDs 455 The privacy risks of using MAC addresses displayed in Interface 456 Identifiers are important. The IPv6 packets can be captured easily 457 in the Internet and on-link in public roads. For this reason, an 458 attacker may realize many attacks on privacy. One such attack on 459 802.11-OCB is to capture, store and correlate Company ID information 460 present in MAC addresses of many cars (e.g. listen for Router 461 Advertisements, or other IPv6 application data packets, and record 462 the value of the source address in these packets). Further 463 correlation of this information with other data captured by other 464 means, or other visual information (car color, others) MAY constitute 465 privacy risks. 467 5.2. MAC Address and Interface ID Generation 469 In 802.11-OCB networks, the MAC addresses MAY change during well 470 defined renumbering events. In the moment the MAC address is changed 471 on an 802.11-OCB interface all the Interface Identifiers of IPv6 472 addresses assigned to that interface MUST change. 474 The policy dictating when the MAC address is changed on the 475 802.11-OCB interface is to-be-determined. For more information on 476 the motivation of this policy please refer to the privacy discussion 477 in Appendix C. 479 A 'randomized' MAC address has the following characteristics: 481 o Bit "Local/Global" set to "locally admninistered". 483 o Bit "Unicast/Multicast" set to "Unicast". 485 o The 46 remaining bits are set to a random value, using a random 486 number generator that meets the requirements of [RFC4086]. 488 To meet the randomization requirements for the 46 remaining bits, a 489 hash function may be used. For example, the SHA256 hash function may 490 be used with input a 256 bit local secret, the 'nominal' MAC Address 491 of the interface, and a representation of the date and time of the 492 renumbering event. 494 A randomized Interface ID has the same characteristics of a 495 randomized MAC address, except the length in bits. A MAC address 496 SHOULD be of length 48 decimal. An Interface ID SHOULD be of length 497 specified in other documents. 499 5.3. Pseudonym Handling 501 The demand for privacy protection of vehicles' and drivers' 502 identities, which could be granted by using a pseudonym or alias 503 identity at the same time, may hamper the required confidentiality of 504 messages and trust between participants - especially in safety 505 critical vehicular communication. 507 o Particular challenges arise when the pseudonymization mechanism 508 used relies on (randomized) re-addressing. 510 o A proper pseudonymization tool operated by a trusted third party 511 may be needed to ensure both aspects simultaneously (privacy 512 protection on one hand and trust between participants on another 513 hand). 515 o This is discussed in Section 4.4 and Section 5 of this document. 517 o Pseudonymity is also discussed in 518 [I-D.ietf-ipwave-vehicular-networking] in its sections 4.2.4 and 519 5.1.2. 521 6. IANA Considerations 523 No request to IANA. 525 7. Contributors 527 Christian Huitema, Tony Li. 529 Romain Kuntz contributed extensively about IPv6 handovers between 530 links running outside the context of a BSS (802.11-OCB links). 532 Tim Leinmueller contributed the idea of the use of IPv6 over 533 802.11-OCB for distribution of certificates. 535 Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey 536 Voronov provided significant feedback on the experience of using IP 537 messages over 802.11-OCB in initial trials. 539 Michelle Wetterwald contributed extensively the MTU discussion, 540 offered the ETSI ITS perspective, and reviewed other parts of the 541 document. 543 8. Acknowledgements 545 The authors would like to thank Witold Klaudel, Ryuji Wakikawa, 546 Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan 547 Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray 548 Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, 549 Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne, 550 Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark, 551 Bob Moskowitz, Andrew Dryden, Georg Mayer, Dorothy Stanley, Sandra 552 Cespedes, Mariano Falcitelli, Sri Gundavelli, Abdussalam Baryun, 553 Margaret Cullen, Erik Kline, Carlos Jesus Bernardos Cano, Ronald in 554 't Velt, Katrin Sjoberg, Roland Bless, Tijink Jasja, Kevin Smith, 555 Brian Carpenter, Julian Reschke, Mikael Abrahamsson, Dirk von Hugo, 556 Lorenzo Colitti, Pascal Thubert, Ole Troan, Jinmei Tatuya and William 557 Whyte. Their valuable comments clarified particular issues and 558 generally helped to improve the document. 560 Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB 561 drivers for linux and described how. 563 For the multicast discussion, the authors would like to thank Owen 564 DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and 565 participants to discussions in network working groups. 567 The authors would like to thank participants to the Birds-of- 568 a-Feather "Intelligent Transportation Systems" meetings held at IETF 569 in 2016. 571 Human Rights Protocol Considerations review by Amelia Andersdotter. 573 9. References 575 9.1. Normative References 577 [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission 578 of IP datagrams over IEEE 802 networks", STD 43, RFC 1042, 579 DOI 10.17487/RFC1042, February 1988, 580 . 582 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 583 Requirement Levels", BCP 14, RFC 2119, 584 DOI 10.17487/RFC2119, March 1997, 585 . 587 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 588 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 589 . 591 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 592 DOI 10.17487/RFC2818, May 2000, 593 . 595 [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related 596 Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, 597 . 599 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 600 "SEcure Neighbor Discovery (SEND)", RFC 3971, 601 DOI 10.17487/RFC3971, March 2005, 602 . 604 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 605 "Randomness Requirements for Security", BCP 106, RFC 4086, 606 DOI 10.17487/RFC4086, June 2005, 607 . 609 [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast 610 Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005, 611 . 613 [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, 614 "Internet X.509 Public Key Infrastructure Certificate 615 Management Protocol (CMP)", RFC 4210, 616 DOI 10.17487/RFC4210, September 2005, 617 . 619 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 620 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 621 2006, . 623 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 624 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 625 December 2005, . 627 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 628 DOI 10.17487/RFC4302, December 2005, 629 . 631 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 632 RFC 4303, DOI 10.17487/RFC4303, December 2005, 633 . 635 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 636 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 637 DOI 10.17487/RFC4861, September 2007, 638 . 640 [RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast 641 Extensions to the Security Architecture for the Internet 642 Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008, 643 . 645 [RFC5415] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, 646 Ed., "Control And Provisioning of Wireless Access Points 647 (CAPWAP) Protocol Specification", RFC 5415, 648 DOI 10.17487/RFC5415, March 2009, 649 . 651 [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing 652 Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889, 653 September 2010, . 655 [RFC6059] Krishnan, S. and G. Daley, "Simple Procedures for 656 Detecting Network Attachment in IPv6", RFC 6059, 657 DOI 10.17487/RFC6059, November 2010, 658 . 660 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 661 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 662 2011, . 664 [RFC7042] Eastlake 3rd, D. and J. Abley, "IANA Considerations and 665 IETF Protocol and Documentation Usage for IEEE 802 666 Parameters", BCP 141, RFC 7042, DOI 10.17487/RFC7042, 667 October 2013, . 669 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 670 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 671 February 2014, . 673 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 674 Interface Identifiers with IPv6 Stateless Address 675 Autoconfiguration (SLAAC)", RFC 7217, 676 DOI 10.17487/RFC7217, April 2014, 677 . 679 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 680 Considerations for IPv6 Address Generation Mechanisms", 681 RFC 7721, DOI 10.17487/RFC7721, March 2016, 682 . 684 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 685 "Recommendation on Stable IPv6 Interface Identifiers", 686 RFC 8064, DOI 10.17487/RFC8064, February 2017, 687 . 689 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 690 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 691 May 2017, . 693 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 694 (IPv6) Specification", STD 86, RFC 8200, 695 DOI 10.17487/RFC8200, July 2017, 696 . 698 9.2. Informative References 700 [ETSI-sec-archi] 701 "ETSI TS 102 940 V1.2.1 (2016-11), ETSI Technical 702 Specification, Intelligent Transport Systems (ITS); 703 Security; ITS communications security architecture and 704 security management, November 2016. Downloaded on 705 September 9th, 2017, freely available from ETSI website at 706 URL http://www.etsi.org/deliver/ 707 etsi_ts/102900_102999/102940/01.02.01_60/ 708 ts_102940v010201p.pdf". 710 [I-D.ietf-ipwave-vehicular-networking] 711 Jeong, J., "IP Wireless Access in Vehicular Environments 712 (IPWAVE): Problem Statement and Use Cases", draft-ietf- 713 ipwave-vehicular-networking-08 (work in progress), March 714 2019. 716 [I-D.ietf-mboned-ieee802-mcast-problems] 717 Perkins, C., McBride, M., Stanley, D., Kumari, W., and J. 718 Zuniga, "Multicast Considerations over IEEE 802 Wireless 719 Media", draft-ietf-mboned-ieee802-mcast-problems-04 (work 720 in progress), November 2018. 722 [IEEE-1609.2] 723 "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access 724 in Vehicular Environments (WAVE) -- Security Services for 725 Applications and Management Messages. Example URL 726 http://ieeexplore.ieee.org/document/7426684/ accessed on 727 August 17th, 2017.". 729 [IEEE-1609.3] 730 "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access 731 in Vehicular Environments (WAVE) -- Networking Services. 732 Example URL http://ieeexplore.ieee.org/document/7458115/ 733 accessed on August 17th, 2017.". 735 [IEEE-1609.4] 736 "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access 737 in Vehicular Environments (WAVE) -- Multi-Channel 738 Operation. Example URL 739 http://ieeexplore.ieee.org/document/7435228/ accessed on 740 August 17th, 2017.". 742 [IEEE-802.11-2016] 743 "IEEE Standard 802.11-2016 - IEEE Standard for Information 744 Technology - Telecommunications and information exchange 745 between systems Local and metropolitan area networks - 746 Specific requirements - Part 11: Wireless LAN Medium 747 Access Control (MAC) and Physical Layer (PHY) 748 Specifications. Status - Active Standard. Description 749 retrieved freely; the document itself is also freely 750 available, but with some difficulty (requires 751 registration); description and document retrieved on April 752 8th, 2019, starting from URL 753 https://standards.ieee.org/findstds/ 754 standard/802.11-2016.html". 756 [IEEE-802.11p-2010] 757 "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information 758 Technology - Telecommunications and information exchange 759 between systems - Local and metropolitan area networks - 760 Specific requirements, Part 11: Wireless LAN Medium Access 761 Control (MAC) and Physical Layer (PHY) Specifications, 762 Amendment 6: Wireless Access in Vehicular Environments; 763 document freely available at URL 764 http://standards.ieee.org/getieee802/ 765 download/802.11p-2010.pdf retrieved on September 20th, 766 2013.". 768 Appendix A. ChangeLog 770 The changes are listed in reverse chronological order, most recent 771 changes appearing at the top of the list. 773 -42: removed 118 len IID; points to 'other documents' for the length 774 of Interface ID; removed 'directly using' phrase for LLs in a subnet. 776 -41: updated a reference from draft-ietf-ipwave-vehicular-networking- 777 survey to draft-ietf-ipwave-vehicular-networking; clarified the link- 778 local text by eliminating link-local addresses and prefixes 779 altogether and referring to RFC4861 which requires the prefixes; 780 added a statement about the subnet being a not multi-link subnet. 782 -40: added a phrase in appendix to further described a condition 783 where ND on OCB may not work; that phrase contains a placeholder; the 784 placeholder is 'TBD' (To Be Defined). 786 -39: removed a reference to an expired draft trying to update the 787 IPv6-over-Ethernet spec 'RFC2464bis'; added text in the subnet 788 structure section saying nodes MUST be able to communicate directly 789 using their link-local addresses. 791 -38: removed the word "fe80::/10". 793 -37: added a section about issues on ND wireless; added the qualifier 794 'baseline' to using ND on 802.11-OCB; improved the description of the 795 reference to 802.11-2016 document, with a qualifier about the 796 difficulty of accessing it, even though it is free. 798 -36: removed a phrase about the IID formation and MAC generation, but 799 left in the section 5.2 that describes how it happens. 801 -35: addressing the the intarea review: clarified a small apparent 802 contradiction between two parts of text that use the old MAC-based 803 IIDs (clarified by using qualifiers from each other: transition time, 804 and ll addresses); sequenced closer the LL and Stateless Autoconf 805 sections, instead of spacing them; shortened the paragraph of Opaque 806 IIDs; moved the privacy risks of in-clear IIDs in the security 807 section; removed a short phrase duplicating the idea of privacy 808 risks; added third time a reference to the 802.11-2016 document; used 809 'the hidden terminal' text; updated the Terminology section with new 810 BCP-14 text 'MUST' to include RFC8174. 812 -33: substituted 'movement detection' for 'handover behaviour' in 813 introductory text; removed redundant phrase referring to Security 814 Considerations section; removed the phrase about forming mechanisms 815 being left out, as IP is not much concerned about L2 forming; moved 816 the Pseudonym section from main section to end of Security 817 Considerations section (and clarified 'concurrently'); capitalized 818 SHOULD consider OCB in WiFi multicast problems, and referred to more 819 recent I-D on topic; removed several phrases in a paragraph about 820 oui.txt and MAC presence in IPv6 address, as they are well known 821 info, but clarified the example of privacy risk of Company ID in MAC 822 addresses in public roads; clarified that ND MUST be used over 823 802.11-OCB. 825 -32: significantly shortened the relevant ND/OCB paragraph. It now 826 just states ND is used over OCB, w/o detailing. 828 -31: filled in the section titled "Pseudonym Handling"; removed a 829 'MAY NOT' phrase about possibility of having other prefix than the LL 830 on the link between cars; shortened and improved the paragraph about 831 Mobile IPv6, now with DNAv6; improved the ND text about ND 832 retransmissions with relationship to packet loss; changed the title 833 of an appendix from 'EPD' to 'Protocol Layering'; improved the 834 'Aspects introduced by OCB' appendix with a few phrases about the 835 channel use and references. 837 -30: a clarification on the reliability of ND over OCB and over 838 802.11. 840 -29: 842 o 844 -28: 846 o Created a new section 'Pseudonym Handling'. 848 o removed the 'Vehicle ID' appendix. 850 o improved the address generation from random MAC address. 852 o shortened Term IP-RSU definition. 854 o removed refs to two detail Clauses in IEEE documents, kept just 855 these latter. 857 -27: part 1 of addressing Human Rights review from IRTF. Removed 858 appendices F.2 and F.3. Shortened definition of IP-RSU. Removed 859 reference to 1609.4. A few other small changes, see diff. 861 -26: moved text from SLAAC section and from Design Considerations 862 appendix about privacy into a new Privacy Condiderations subsection 863 of the Security section; reformulated the SLAAC and IID sections to 864 stress only LLs can use EUI-64; removed the "GeoIP" wireshark 865 explanation; reformulated SLAAC and LL sections; added brief mention 866 of need of use LLs; clarified text about MAC address changes; dropped 867 pseudonym discussion; changed title of section describing examples of 868 packet formats. 870 -25: added a reference to 'IEEE Management Information Base', instead 871 of just 'Management Information Base'; added ref to further 872 appendices in the introductory phrases; improved text for IID 873 formation for SLAAC, inserting recommendation for RFC8064 before 874 RFC2464. 876 From draft-ietf-ipwave-ipv6-over-80211ocb-23 to draft-ietf-ipwave- 877 ipv6-over-80211ocb-24 879 o Nit: wrote "IPWAVE Working Group" on the front page, instead of 880 "Network Working Group". 882 o Addressed the comments on 6MAN: replaced a sentence about ND 883 problem with "is used over 802.11-OCB". 885 From draft-ietf-ipwave-ipv6-over-80211ocb-22 to draft-ietf-ipwave- 886 ipv6-over-80211ocb-23 887 o No content modifications, but check the entire draft chain on 888 IPv6-only: xml2rfc, submission on tools.ietf.org and datatracker. 890 From draft-ietf-ipwave-ipv6-over-80211ocb-21 to draft-ietf-ipwave- 891 ipv6-over-80211ocb-22 893 o Corrected typo, use dash in "802.11-OCB" instead of space. 895 o Improved the Frame Format section: MUST use QoSData, specify the 896 values within; clarified the Ethernet Adaptation Layer text. 898 From draft-ietf-ipwave-ipv6-over-80211ocb-20 to draft-ietf-ipwave- 899 ipv6-over-80211ocb-21 901 o Corrected a few nits and added names in Acknowledgments section. 903 o Removed unused reference to old Internet Draft tsvwg about QoS. 905 From draft-ietf-ipwave-ipv6-over-80211ocb-19 to draft-ietf-ipwave- 906 ipv6-over-80211ocb-20 908 o Reduced the definition of term "802.11-OCB". 910 o Left out of this specification which 802.11 header to use to 911 transmit IP packets in OCB mode (QoS Data header, Data header, or 912 any other). 914 o Added 'MUST' use an Ethernet Adaptation Layer, instead of 'is 915 using' an Ethernet Adaptation Layer. 917 From draft-ietf-ipwave-ipv6-over-80211ocb-18 to draft-ietf-ipwave- 918 ipv6-over-80211ocb-19 920 o Removed the text about fragmentation. 922 o Removed the mentioning of WSMP and GeoNetworking. 924 o Removed the explanation of the binary representation of the 925 EtherType. 927 o Rendered normative the paragraph about unicast and multicast 928 address mapping. 930 o Removed paragraph about addressing model, subnet structure and 931 easiness of using LLs. 933 o Clarified the Type/Subtype field in the 802.11 Header. 935 o Used RECOMMENDED instead of recommended, for the stable interface 936 identifiers. 938 From draft-ietf-ipwave-ipv6-over-80211ocb-17 to draft-ietf-ipwave- 939 ipv6-over-80211ocb-18 941 o Improved the MTU and fragmentation paragraph. 943 From draft-ietf-ipwave-ipv6-over-80211ocb-16 to draft-ietf-ipwave- 944 ipv6-over-80211ocb-17 946 o Susbtituted "MUST be increased" to "is increased" in the MTU 947 section, about fragmentation. 949 From draft-ietf-ipwave-ipv6-over-80211ocb-15 to draft-ietf-ipwave- 950 ipv6-over-80211ocb-16 952 o Removed the definition of the 'WiFi' term and its occurences. 953 Clarified a phrase that used it in Appendix C "Aspects introduced 954 by the OCB mode to 802.11". 956 o Added more normative words: MUST be 0x86DD, MUST fragment if size 957 larger than MTU, Sequence number in 802.11 Data header MUST be 958 increased. 960 From draft-ietf-ipwave-ipv6-over-80211ocb-14 to draft-ietf-ipwave- 961 ipv6-over-80211ocb-15 963 o Added normative term MUST in two places in section "Ethernet 964 Adaptation Layer". 966 From draft-ietf-ipwave-ipv6-over-80211ocb-13 to draft-ietf-ipwave- 967 ipv6-over-80211ocb-14 969 o Created a new Appendix titled "Extra Terminology" that contains 970 terms DSRC, DSRCS, OBU, RSU as defined outside IETF. Some of them 971 are used in the main Terminology section. 973 o Added two paragraphs explaining that ND and Mobile IPv6 have 974 problems working over 802.11-OCB, yet their adaptations is not 975 specified in this document. 977 From draft-ietf-ipwave-ipv6-over-80211ocb-12 to draft-ietf-ipwave- 978 ipv6-over-80211ocb-13 980 o Substituted "IP-OBU" for "OBRU", and "IP-RSU" for "RSRU" 981 throughout and improved OBU-related definitions in the Terminology 982 section. 984 From draft-ietf-ipwave-ipv6-over-80211ocb-11 to draft-ietf-ipwave- 985 ipv6-over-80211ocb-12 987 o Improved the appendix about "MAC Address Generation" by expressing 988 the technique to be an optional suggestion, not a mandatory 989 mechanism. 991 From draft-ietf-ipwave-ipv6-over-80211ocb-10 to draft-ietf-ipwave- 992 ipv6-over-80211ocb-11 994 o Shortened the paragraph on forming/terminating 802.11-OCB links. 996 o Moved the draft tsvwg-ieee-802-11 to Informative References. 998 From draft-ietf-ipwave-ipv6-over-80211ocb-09 to draft-ietf-ipwave- 999 ipv6-over-80211ocb-10 1001 o Removed text requesting a new Group ID for multicast for OCB. 1003 o Added a clarification of the meaning of value "3333" in the 1004 section Address Mapping -- Multicast. 1006 o Added note clarifying that in Europe the regional authority is not 1007 ETSI, but "ECC/CEPT based on ENs from ETSI". 1009 o Added note stating that the manner in which two STAtions set their 1010 communication channel is not described in this document. 1012 o Added a time qualifier to state that the "each node is represented 1013 uniquely at a certain point in time." 1015 o Removed text "This section may need to be moved" (the "Reliability 1016 Requirements" section). This section stays there at this time. 1018 o In the term definition "802.11-OCB" added a note stating that "any 1019 implementation should comply with standards and regulations set in 1020 the different countries for using that frequency band." 1022 o In the RSU term definition, added a sentence explaining the 1023 difference between RSU and RSRU: in terms of number of interfaces 1024 and IP forwarding. 1026 o Replaced "with at least two IP interfaces" with "with at least two 1027 real or virtual IP interfaces". 1029 o Added a term in the Terminology for "OBU". However the definition 1030 is left empty, as this term is defined outside IETF. 1032 o Added a clarification that it is an OBU or an OBRU in this phrase 1033 "A vehicle embarking an OBU or an OBRU". 1035 o Checked the entire document for a consistent use of terms OBU and 1036 OBRU. 1038 o Added note saying that "'p' is a letter identifying the 1039 Ammendment". 1041 o Substituted lower case for capitals SHALL or MUST in the 1042 Appendices. 1044 o Added reference to RFC7042, helpful in the 3333 explanation. 1045 Removed reference to individual submission draft-petrescu-its- 1046 scenario-reqs and added reference to draft-ietf-ipwave-vehicular- 1047 networking-survey. 1049 o Added figure captions, figure numbers, and references to figure 1050 numbers instead of 'below'. Replaced "section Section" with 1051 "section" throughout. 1053 o Minor typographical errors. 1055 From draft-ietf-ipwave-ipv6-over-80211ocb-08 to draft-ietf-ipwave- 1056 ipv6-over-80211ocb-09 1058 o Significantly shortened the Address Mapping sections, by text 1059 copied from RFC2464, and rather referring to it. 1061 o Moved the EPD description to an Appendix on its own. 1063 o Shortened the Introduction and the Abstract. 1065 o Moved the tutorial section of OCB mode introduced to .11, into an 1066 appendix. 1068 o Removed the statement that suggests that for routing purposes a 1069 prefix exchange mechanism could be needed. 1071 o Removed refs to RFC3963, RFC4429 and RFC6775; these are about ND, 1072 MIP/NEMO and oDAD; they were referred in the handover discussion 1073 section, which is out. 1075 o Updated a reference from individual submission to now a WG item in 1076 IPWAVE: the survey document. 1078 o Added term definition for WiFi. 1080 o Updated the authorship and expanded the Contributors section. 1082 o Corrected typographical errors. 1084 From draft-ietf-ipwave-ipv6-over-80211ocb-07 to draft-ietf-ipwave- 1085 ipv6-over-80211ocb-08 1087 o Removed the per-channel IPv6 prohibition text. 1089 o Corrected typographical errors. 1091 From draft-ietf-ipwave-ipv6-over-80211ocb-06 to draft-ietf-ipwave- 1092 ipv6-over-80211ocb-07 1094 o Added new terms: OBRU and RSRU ('R' for Router). Refined the 1095 existing terms RSU and OBU, which are no longer used throughout 1096 the document. 1098 o Improved definition of term "802.11-OCB". 1100 o Clarified that OCB does not "strip" security, but that the 1101 operation in OCB mode is "stripped off of all .11 security". 1103 o Clarified that theoretical OCB bandwidth speed is 54mbits, but 1104 that a commonly observed bandwidth in IP-over-OCB is 12mbit/s. 1106 o Corrected typographical errors, and improved some phrasing. 1108 From draft-ietf-ipwave-ipv6-over-80211ocb-05 to draft-ietf-ipwave- 1109 ipv6-over-80211ocb-06 1111 o Updated references of 802.11-OCB document from -2012 to the IEEE 1112 802.11-2016. 1114 o In the LL address section, and in SLAAC section, added references 1115 to 7217 opaque IIDs and 8064 stable IIDs. 1117 From draft-ietf-ipwave-ipv6-over-80211ocb-04 to draft-ietf-ipwave- 1118 ipv6-over-80211ocb-05 1120 o Lengthened the title and cleanded the abstract. 1122 o Added text suggesting LLs may be easy to use on OCB, rather than 1123 GUAs based on received prefix. 1125 o Added the risks of spoofing and hijacking. 1127 o Removed the text speculation on adoption of the TSA message. 1129 o Clarified that the ND protocol is used. 1131 o Clarified what it means "No association needed". 1133 o Added some text about how two STAs discover each other. 1135 o Added mention of external (OCB) and internal network (stable), in 1136 the subnet structure section. 1138 o Added phrase explaining that both .11 Data and .11 QoS Data 1139 headers are currently being used, and may be used in the future. 1141 o Moved the packet capture example into an Appendix Implementation 1142 Status. 1144 o Suggested moving the reliability requirements appendix out into 1145 another document. 1147 o Added a IANA Consiserations section, with content, requesting for 1148 a new multicast group "all OCB interfaces". 1150 o Added new OBU term, improved the RSU term definition, removed the 1151 ETTC term, replaced more occurences of 802.11p, 802.11-OCB with 1152 802.11-OCB. 1154 o References: 1156 * Added an informational reference to ETSI's IPv6-over- 1157 GeoNetworking. 1159 * Added more references to IETF and ETSI security protocols. 1161 * Updated some references from I-D to RFC, and from old RFC to 1162 new RFC numbers. 1164 * Added reference to multicast extensions to IPsec architecture 1165 RFC. 1167 * Added a reference to 2464-bis. 1169 * Removed FCC informative references, because not used. 1171 o Updated the affiliation of one author. 1173 o Reformulation of some phrases for better readability, and 1174 correction of typographical errors. 1176 From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave- 1177 ipv6-over-80211ocb-04 1179 o Removed a few informative references pointing to Dx draft IEEE 1180 1609 documents. 1182 o Removed outdated informative references to ETSI documents. 1184 o Added citations to IEEE 1609.2, .3 and .4-2016. 1186 o Minor textual issues. 1188 From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave- 1189 ipv6-over-80211ocb-03 1191 o Keep the previous text on multiple addresses, so remove talk about 1192 MIP6, NEMOv6 and MCoA. 1194 o Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon. 1196 o Clarified the figure showing Infrastructure mode and OCB mode side 1197 by side. 1199 o Added a reference to the IP Security Architecture RFC. 1201 o Detailed the IPv6-per-channel prohibition paragraph which reflects 1202 the discussion at the last IETF IPWAVE WG meeting. 1204 o Added section "Address Mapping -- Unicast". 1206 o Added the ".11 Trailer" to pictures of 802.11 frames. 1208 o Added text about SNAP carrying the Ethertype. 1210 o New RSU definition allowing for it be both a Router and not 1211 necessarily a Router some times. 1213 o Minor textual issues. 1215 From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave- 1216 ipv6-over-80211ocb-02 1218 o Replaced almost all occurences of 802.11p with 802.11-OCB, leaving 1219 only when explanation of evolution was necessary. 1221 o Shortened by removing parameter details from a paragraph in the 1222 Introduction. 1224 o Moved a reference from Normative to Informative. 1226 o Added text in intro clarifying there is no handover spec at IEEE, 1227 and that 1609.2 does provide security services. 1229 o Named the contents the fields of the EthernetII header (including 1230 the Ethertype bitstring). 1232 o Improved relationship between two paragraphs describing the 1233 increase of the Sequence Number in 802.11 header upon IP 1234 fragmentation. 1236 o Added brief clarification of "tracking". 1238 From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave- 1239 ipv6-over-80211ocb-01 1241 o Introduced message exchange diagram illustrating differences 1242 between 802.11 and 802.11 in OCB mode. 1244 o Introduced an appendix listing for information the set of 802.11 1245 messages that may be transmitted in OCB mode. 1247 o Removed appendix sections "Privacy Requirements", "Authentication 1248 Requirements" and "Security Certificate Generation". 1250 o Removed appendix section "Non IP Communications". 1252 o Introductory phrase in the Security Considerations section. 1254 o Improved the definition of "OCB". 1256 o Introduced theoretical stacked layers about IPv6 and IEEE layers 1257 including EPD. 1259 o Removed the appendix describing the details of prohibiting IPv6 on 1260 certain channels relevant to 802.11-OCB. 1262 o Added a brief reference in the privacy text about a precise clause 1263 in IEEE 1609.3 and .4. 1265 o Clarified the definition of a Road Side Unit. 1267 o Removed the discussion about security of WSA (because is non-IP). 1269 o Removed mentioning of the GeoNetworking discussion. 1271 o Moved references to scientific articles to a separate 'overview' 1272 draft, and referred to it. 1274 Appendix B. 802.11p 1276 The term "802.11p" is an earlier definition. The behaviour of 1277 "802.11p" networks is rolled in the document IEEE Std 802.11-2016. 1278 In that document the term 802.11p disappears. Instead, each 802.11p 1279 feature is conditioned by the IEEE Management Information Base (MIB) 1280 attribute "OCBActivated" [IEEE-802.11-2016]. Whenever OCBActivated 1281 is set to true the IEEE Std 802.11-OCB state is activated. For 1282 example, an 802.11 STAtion operating outside the context of a basic 1283 service set has the OCBActivated flag set. Such a station, when it 1284 has the flag set, uses a BSS identifier equal to ff:ff:ff:ff:ff:ff. 1286 Appendix C. Aspects introduced by the OCB mode to 802.11 1288 In the IEEE 802.11-OCB mode, all nodes in the wireless range can 1289 directly communicate with each other without involving authentication 1290 or association procedures. In OCB mode, the manner in which channels 1291 are selected and used is simplified compared to when in BSS mode. 1292 Contrary to BSS mode, at link layer, it is necessary to set 1293 statically the same channel number (or frequency) on two stations 1294 that need to communicate with each other (in BSS mode this channel 1295 set operation is performed automatically during 'scanning'). The 1296 manner in which stations set their channel number in OCB mode is not 1297 specified in this document. Stations STA1 and STA2 can exchange IP 1298 packets only if they are set on the same channel. At IP layer, they 1299 then discover each other by using the IPv6 Neighbor Discovery 1300 protocol. The allocation of a particular channel for a particular 1301 use is defined statically in standards authored by ETSI (in Europe), 1302 FCC in America, and similar organisations in South Korea, Japan and 1303 other parts of the world. 1305 Briefly, the IEEE 802.11-OCB mode has the following properties: 1307 o The use by each node of a 'wildcard' BSSID (i.e., each bit of the 1308 BSSID is set to 1) 1310 o No IEEE 802.11 Beacon frames are transmitted 1312 o No authentication is required in order to be able to communicate 1314 o No association is needed in order to be able to communicate 1316 o No encryption is provided in order to be able to communicate 1318 o Flag dot11OCBActivated is set to true 1319 All the nodes in the radio communication range (IP-OBU and IP-RSU) 1320 receive all the messages transmitted (IP-OBU and IP-RSU) within the 1321 radio communications range. The eventual conflict(s) are resolved by 1322 the MAC CDMA function. 1324 The message exchange diagram in Figure 3 illustrates a comparison 1325 between traditional 802.11 and 802.11 in OCB mode. The 'Data' 1326 messages can be IP packets such as HTTP or others. Other 802.11 1327 management and control frames (non IP) may be transmitted, as 1328 specified in the 802.11 standard. For information, the names of 1329 these messages as currently specified by the 802.11 standard are 1330 listed in Appendix G. 1332 STA AP STA1 STA2 1333 | | | | 1334 |<------ Beacon -------| |<------ Data -------->| 1335 | | | | 1336 |---- Probe Req. ----->| |<------ Data -------->| 1337 |<--- Probe Res. ------| | | 1338 | | |<------ Data -------->| 1339 |---- Auth Req. ------>| | | 1340 |<--- Auth Res. -------| |<------ Data -------->| 1341 | | | | 1342 |---- Asso Req. ------>| |<------ Data -------->| 1343 |<--- Asso Res. -------| | | 1344 | | |<------ Data -------->| 1345 |<------ Data -------->| | | 1346 |<------ Data -------->| |<------ Data -------->| 1348 (i) 802.11 Infrastructure mode (ii) 802.11-OCB mode 1350 Figure 3: Difference between messages exchanged on 802.11 (left) and 1351 802.11-OCB (right) 1353 The interface 802.11-OCB was specified in IEEE Std 802.11p (TM) -2010 1354 [IEEE-802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, 1355 titled "Amendment 6: Wireless Access in Vehicular Environments". 1356 Since then, this amendment has been integrated in IEEE 802.11(TM) 1357 -2012 and -2016 [IEEE-802.11-2016]. 1359 In document 802.11-2016, anything qualified specifically as 1360 "OCBActivated", or "outside the context of a basic service" set to be 1361 true, then it is actually referring to OCB aspects introduced to 1362 802.11. 1364 In order to delineate the aspects introduced by 802.11-OCB to 802.11, 1365 we refer to the earlier [IEEE-802.11p-2010]. The amendment is 1366 concerned with vehicular communications, where the wireless link is 1367 similar to that of Wireless LAN (using a PHY layer specified by 1368 802.11a/b/g/n), but which needs to cope with the high mobility factor 1369 inherent in scenarios of communications between moving vehicles, and 1370 between vehicles and fixed infrastructure deployed along roads. 1371 While 'p' is a letter identifying the Ammendment, just like 'a, b, g' 1372 and 'n' are, 'p' is concerned more with MAC modifications, and a 1373 little with PHY modifications; the others are mainly about PHY 1374 modifications. It is possible in practice to combine a 'p' MAC with 1375 an 'a' PHY by operating outside the context of a BSS with OFDM at 1376 5.4GHz and 5.9GHz. 1378 The 802.11-OCB links are specified to be compatible as much as 1379 possible with the behaviour of 802.11a/b/g/n and future generation 1380 IEEE WLAN links. From the IP perspective, an 802.11-OCB MAC layer 1381 offers practically the same interface to IP as the 802.11a/b/g/n and 1382 802.3. A packet sent by an IP-OBU may be received by one or multiple 1383 IP-RSUs. The link-layer resolution is performed by using the IPv6 1384 Neighbor Discovery protocol. 1386 To support this similarity statement (IPv6 is layered on top of LLC 1387 on top of 802.11-OCB, in the same way that IPv6 is layered on top of 1388 LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on 1389 top of 802.3 (for Ethernet)) it is useful to analyze the differences 1390 between 802.11-OCB and 802.11 specifications. During this analysis, 1391 we note that whereas 802.11-OCB lists relatively complex and numerous 1392 changes to the MAC layer (and very little to the PHY layer), there 1393 are only a few characteristics which may be important for an 1394 implementation transmitting IPv6 packets on 802.11-OCB links. 1396 The most important 802.11-OCB point which influences the IPv6 1397 functioning is the OCB characteristic; an additional, less direct 1398 influence, is the maximum bandwidth afforded by the PHY modulation/ 1399 demodulation methods and channel access specified by 802.11-OCB. The 1400 maximum bandwidth theoretically possible in 802.11-OCB is 54 Mbit/s 1401 (when using, for example, the following parameters: 20 MHz channel; 1402 modulation 64-QAM; coding rate R is 3/4); in practice of IP-over- 1403 802.11-OCB a commonly observed figure is 12Mbit/s; this bandwidth 1404 allows the operation of a wide range of protocols relying on IPv6. 1406 o Operation Outside the Context of a BSS (OCB): the (earlier 1407 802.11p) 802.11-OCB links are operated without a Basic Service Set 1408 (BSS). This means that the frames IEEE 802.11 Beacon, Association 1409 Request/Response, Authentication Request/Response, and similar, 1410 are not used. The used identifier of BSS (BSSID) has a 1411 hexadecimal value always 0xffffffffffff (48 '1' bits, represented 1412 as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' 1413 BSSID), as opposed to an arbitrary BSSID value set by 1414 administrator (e.g. 'My-Home-AccessPoint'). The OCB operation - 1415 namely the lack of beacon-based scanning and lack of 1416 authentication - should be taken into account when the Mobile IPv6 1417 protocol [RFC6275] and the protocols for IP layer security 1418 [RFC4301] are used. The way these protocols adapt to OCB is not 1419 described in this document. 1421 o Timing Advertisement: is a new message defined in 802.11-OCB, 1422 which does not exist in 802.11a/b/g/n. This message is used by 1423 stations to inform other stations about the value of time. It is 1424 similar to the time as delivered by a GNSS system (Galileo, GPS, 1425 ...) or by a cellular system. This message is optional for 1426 implementation. 1428 o Frequency range: this is a characteristic of the PHY layer, with 1429 almost no impact on the interface between MAC and IP. However, it 1430 is worth considering that the frequency range is regulated by a 1431 regional authority (ARCEP, ECC/CEPT based on ENs from ETSI, FCC, 1432 etc.); as part of the regulation process, specific applications 1433 are associated with specific frequency ranges. In the case of 1434 802.11-OCB, the regulator associates a set of frequency ranges, or 1435 slots within a band, to the use of applications of vehicular 1436 communications, in a band known as "5.9GHz". The 5.9GHz band is 1437 different from the 2.4GHz and 5GHz bands used by Wireless LAN. 1438 However, as with Wireless LAN, the operation of 802.11-OCB in 1439 "5.9GHz" bands is exempt from owning a license in EU (in US the 1440 5.9GHz is a licensed band of spectrum; for the fixed 1441 infrastructure an explicit FCC authorization is required; for an 1442 on-board device a 'licensed-by-rule' concept applies: rule 1443 certification conformity is required.) Technical conditions are 1444 different than those of the bands "2.4GHz" or "5GHz". The allowed 1445 power levels, and implicitly the maximum allowed distance between 1446 vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20 1447 dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum 1448 distance of approximately 1km, compared to approximately 50m. 1449 Additionally, specific conditions related to congestion avoidance, 1450 jamming avoidance, and radar detection are imposed on the use of 1451 DSRC (in US) and on the use of frequencies for Intelligent 1452 Transportation Systems (in EU), compared to Wireless LAN 1453 (802.11a/b/g/n). 1455 o 'Half-rate' encoding: as the frequency range, this parameter is 1456 related to PHY, and thus has not much impact on the interface 1457 between the IP layer and the MAC layer. 1459 o In vehicular communications using 802.11-OCB links, there are 1460 strong privacy requirements with respect to addressing. While the 1461 802.11-OCB standard does not specify anything in particular with 1462 respect to MAC addresses, in these settings there exists a strong 1463 need for dynamic change of these addresses (as opposed to the non- 1464 vehicular settings - real wall protection - where fixed MAC 1465 addresses do not currently pose some privacy risks). This is 1466 further described in Section 5. A relevant function is described 1467 in documents IEEE 1609.3-2016 [IEEE-1609.3] and IEEE 1609.4-2016 1468 [IEEE-1609.4]. 1470 Appendix D. Changes Needed on a software driver 802.11a to become a 1471 802.11-OCB driver 1473 The 802.11p amendment modifies both the 802.11 stack's physical and 1474 MAC layers but all the induced modifications can be quite easily 1475 obtained by modifying an existing 802.11a ad-hoc stack. 1477 Conditions for a 802.11a hardware to be 802.11-OCB compliant: 1479 o The PHY entity shall be an orthogonal frequency division 1480 multiplexing (OFDM) system. It must support the frequency bands 1481 on which the regulator recommends the use of ITS communications, 1482 for example using IEEE 802.11-OCB layer, in France: 5875MHz to 1483 5925MHz. 1485 o The OFDM system must provide a "half-clocked" operation using 10 1486 MHz channel spacings. 1488 o The chip transmit spectrum mask must be compliant to the "Transmit 1489 spectrum mask" from the IEEE 802.11p amendment (but experimental 1490 environments tolerate otherwise). 1492 o The chip should be able to transmit up to 44.8 dBm when used by 1493 the US government in the United States, and up to 33 dBm in 1494 Europe; other regional conditions apply. 1496 Changes needed on the network stack in OCB mode: 1498 o Physical layer: 1500 * The chip must use the Orthogonal Frequency Multiple Access 1501 (OFDM) encoding mode. 1503 * The chip must be set in half-mode rate mode (the internal clock 1504 frequency is divided by two). 1506 * The chip must use dedicated channels and should allow the use 1507 of higher emission powers. This may require modifications to 1508 the local computer file that describes regulatory domains 1509 rules, if used by the kernel to enforce local specific 1510 restrictions. Such modifications to the local computer file 1511 must respect the location-specific regulatory rules. 1513 MAC layer: 1515 * All management frames (beacons, join, leave, and others) 1516 emission and reception must be disabled except for frames of 1517 subtype Action and Timing Advertisement (defined below). 1519 * No encryption key or method must be used. 1521 * Packet emission and reception must be performed as in ad-hoc 1522 mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff). 1524 * The functions related to joining a BSS (Association Request/ 1525 Response) and for authentication (Authentication Request/Reply, 1526 Challenge) are not called. 1528 * The beacon interval is always set to 0 (zero). 1530 * Timing Advertisement frames, defined in the amendment, should 1531 be supported. The upper layer should be able to trigger such 1532 frames emission and to retrieve information contained in 1533 received Timing Advertisements. 1535 Appendix E. Protocol Layering 1537 A more theoretical and detailed view of layer stacking, and 1538 interfaces between the IP layer and 802.11-OCB layers, is illustrated 1539 in Figure 4. The IP layer operates on top of the EtherType Protocol 1540 Discrimination (EPD); this Discrimination layer is described in IEEE 1541 Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP 1542 (Link Layer Control Service Access Point). 1544 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1545 | IPv6 | 1546 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ 1547 { LLC_SAP } 802.11-OCB 1548 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary 1549 | EPD | | | 1550 | | MLME | | 1551 +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | 1552 | MAC Sublayer | | | 802.11-OCB 1553 | and ch. coord. | | SME | Services 1554 +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | 1555 | | PLME | | 1556 | PHY Layer | PLME_SAP | 1557 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1559 Figure 4: EtherType Protocol Discrimination 1561 Appendix F. Design Considerations 1563 The networks defined by 802.11-OCB are in many ways similar to other 1564 networks of the 802.11 family. In theory, the encapsulation of IPv6 1565 over 802.11-OCB could be very similar to the operation of IPv6 over 1566 other networks of the 802.11 family. However, the high mobility, 1567 strong link asymmetry and very short connection makes the 802.11-OCB 1568 link significantly different from other 802.11 networks. Also, the 1569 automotive applications have specific requirements for reliability, 1570 security and privacy, which further add to the particularity of the 1571 802.11-OCB link. 1573 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode 1575 For information, at the time of writing, this is the list of IEEE 1576 802.11 messages that may be transmitted in OCB mode, i.e. when 1577 dot11OCBActivated is true in a STA: 1579 o The STA may send management frames of subtype Action and, if the 1580 STA maintains a TSF Timer, subtype Timing Advertisement; 1582 o The STA may send control frames, except those of subtype PS-Poll, 1583 CF-End, and CF-End plus CFAck; 1585 o The STA may send data frames of subtype Data, Null, QoS Data, and 1586 QoS Null. 1588 Appendix H. Examples of Packet Formats 1590 This section describes an example of an IPv6 Packet captured over a 1591 IEEE 802.11-OCB link. 1593 By way of example we show that there is no modification in the 1594 headers when transmitted over 802.11-OCB networks - they are 1595 transmitted like any other 802.11 and Ethernet packets. 1597 We describe an experiment of capturing an IPv6 packet on an 1598 802.11-OCB link. In topology depicted in Figure 5, the packet is an 1599 IPv6 Router Advertisement. This packet is emitted by a Router on its 1600 802.11-OCB interface. The packet is captured on the Host, using a 1601 network protocol analyzer (e.g. Wireshark); the capture is performed 1602 in two different modes: direct mode and 'monitor' mode. The topology 1603 used during the capture is depicted below. 1605 The packet is captured on the Host. The Host is an IP-OBU containing 1606 an 802.11 interface in format PCI express (an ITRI product). The 1607 kernel runs the ath5k software driver with modifications for OCB 1608 mode. The capture tool is Wireshark. The file format for save and 1609 analyze is 'pcap'. The packet is generated by the Router. The 1610 Router is an IP-RSU (ITRI product). 1612 +--------+ +-------+ 1613 | | 802.11-OCB Link | | 1614 ---| Router |--------------------------------| Host | 1615 | | | | 1616 +--------+ +-------+ 1618 Figure 5: Topology for capturing IP packets on 802.11-OCB 1620 During several capture operations running from a few moments to 1621 several hours, no message relevant to the BSSID contexts were 1622 captured (no Association Request/Response, Authentication Req/Resp, 1623 Beacon). This shows that the operation of 802.11-OCB is outside the 1624 context of a BSSID. 1626 Overall, the captured message is identical with a capture of an IPv6 1627 packet emitted on a 802.11b interface. The contents are precisely 1628 similar. 1630 H.1. Capture in Monitor Mode 1632 The IPv6 RA packet captured in monitor mode is illustrated below. 1633 The radio tap header provides more flexibility for reporting the 1634 characteristics of frames. The Radiotap Header is prepended by this 1635 particular stack and operating system on the Host machine to the RA 1636 packet received from the network (the Radiotap Header is not present 1637 on the air). The implementation-dependent Radiotap Header is useful 1638 for piggybacking PHY information from the chip's registers as data in 1639 a packet understandable by userland applications using Socket 1640 interfaces (the PHY interface can be, for example: power levels, data 1641 rate, ratio of signal to noise). 1643 The packet present on the air is formed by IEEE 802.11 Data Header, 1644 Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. 1646 Radiotap Header v0 1647 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1648 |Header Revision| Header Pad | Header length | 1649 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1650 | Present flags | 1651 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1652 | Data Rate | Pad | 1653 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1655 IEEE 802.11 Data Header 1656 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1657 | Type/Subtype and Frame Ctrl | Duration | 1658 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1659 | Receiver Address... 1660 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1661 ... Receiver Address | Transmitter Address... 1662 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1663 ... Transmitter Address | 1664 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1665 | BSS Id... 1666 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1667 ... BSS Id | Frag Number and Seq Number | 1668 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1670 Logical-Link Control Header 1671 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1672 | DSAP |I| SSAP |C| Control field | Org. code... 1673 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1674 ... Organizational Code | Type | 1675 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1676 IPv6 Base Header 1677 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1678 |Version| Traffic Class | Flow Label | 1679 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1680 | Payload Length | Next Header | Hop Limit | 1681 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1682 | | 1683 + + 1684 | | 1685 + Source Address + 1686 | | 1687 + + 1688 | | 1689 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1690 | | 1691 + + 1692 | | 1693 + Destination Address + 1694 | | 1695 + + 1696 | | 1697 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1699 Router Advertisement 1700 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1701 | Type | Code | Checksum | 1702 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1703 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1704 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1705 | Reachable Time | 1706 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1707 | Retrans Timer | 1708 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1709 | Options ... 1710 +-+-+-+-+-+-+-+-+-+-+-+- 1712 The value of the Data Rate field in the Radiotap header is set to 6 1713 Mb/s. This indicates the rate at which this RA was received. 1715 The value of the Transmitter address in the IEEE 802.11 Data Header 1716 is set to a 48bit value. The value of the destination address is 1717 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS 1718 Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network 1719 protocol analyzer as being "broadcast". The Fragment number and 1720 sequence number fields are together set to 0x90C6. 1722 The value of the Organization Code field in the Logical-Link Control 1723 Header is set to 0x0, recognized as "Encapsulated Ethernet". The 1724 value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise 1725 #86DD), recognized as "IPv6". 1727 A Router Advertisement is periodically sent by the router to 1728 multicast group address ff02::1. It is an icmp packet type 134. The 1729 IPv6 Neighbor Discovery's Router Advertisement message contains an 1730 8-bit field reserved for single-bit flags, as described in [RFC4861]. 1732 The IPv6 header contains the link local address of the router 1733 (source) configured via EUI-64 algorithm, and destination address set 1734 to ff02::1. 1736 The Ethernet Type field in the logical-link control header is set to 1737 0x86dd which indicates that the frame transports an IPv6 packet. In 1738 the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 1739 which is the corresponding multicast MAC address. The BSS id is a 1740 broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link 1741 duration between vehicles and the roadside infrastructure, there is 1742 no need in IEEE 802.11-OCB to wait for the completion of association 1743 and authentication procedures before exchanging data. IEEE 1744 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) 1745 and may start communicating as soon as they arrive on the 1746 communication channel. 1748 H.2. Capture in Normal Mode 1750 The same IPv6 Router Advertisement packet described above (monitor 1751 mode) is captured on the Host, in the Normal mode, and depicted 1752 below. 1754 Ethernet II Header 1755 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1756 | Destination... 1757 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1758 ...Destination | Source... 1759 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1760 ...Source | 1761 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1762 | Type | 1763 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1765 IPv6 Base Header 1766 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1767 |Version| Traffic Class | Flow Label | 1768 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1769 | Payload Length | Next Header | Hop Limit | 1770 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1771 | | 1772 + + 1773 | | 1774 + Source Address + 1775 | | 1776 + + 1777 | | 1778 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1779 | | 1780 + + 1781 | | 1782 + Destination Address + 1783 | | 1784 + + 1785 | | 1786 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1788 Router Advertisement 1789 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1790 | Type | Code | Checksum | 1791 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1792 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1793 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1794 | Reachable Time | 1795 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1796 | Retrans Timer | 1797 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1798 | Options ... 1799 +-+-+-+-+-+-+-+-+-+-+-+- 1801 One notices that the Radiotap Header, the IEEE 802.11 Data Header and 1802 the Logical-Link Control Headers are not present. On the other hand, 1803 a new header named Ethernet II Header is present. 1805 The Destination and Source addresses in the Ethernet II header 1806 contain the same values as the fields Receiver Address and 1807 Transmitter Address present in the IEEE 802.11 Data Header in the 1808 "monitor" mode capture. 1810 The value of the Type field in the Ethernet II header is 0x86DD 1811 (recognized as "IPv6"); this value is the same value as the value of 1812 the field Type in the Logical-Link Control Header in the "monitor" 1813 mode capture. 1815 The knowledgeable experimenter will no doubt notice the similarity of 1816 this Ethernet II Header with a capture in normal mode on a pure 1817 Ethernet cable interface. 1819 An Adaptation layer is inserted on top of a pure IEEE 802.11 MAC 1820 layer, in order to adapt packets, before delivering the payload data 1821 to the applications. It adapts 802.11 LLC/MAC headers to Ethernet II 1822 headers. In further detail, this adaptation consists in the 1823 elimination of the Radiotap, 802.11 and LLC headers, and in the 1824 insertion of the Ethernet II header. In this way, IPv6 runs straight 1825 over LLC over the 802.11-OCB MAC layer; this is further confirmed by 1826 the use of the unique Type 0x86DD. 1828 Appendix I. Extra Terminology 1830 The following terms are defined outside the IETF. They are used to 1831 define the main terms in the main terminology section Section 2. 1833 DSRC (Dedicated Short Range Communication): a term defined outside 1834 the IETF. The US Federal Communications Commission (FCC) Dedicated 1835 Short Range Communication (DSRC) is defined in the Code of Federal 1836 Regulations (CFR) 47, Parts 90 and 95. This Code is referred in the 1837 definitions below. At the time of the writing of this Internet 1838 Draft, the last update of this Code was dated October 1st, 2010. 1840 DSRCS (Dedicated Short-Range Communications Services): a term defined 1841 outside the IETF. The use of radio techniques to transfer data over 1842 short distances between roadside and mobile units, between mobile 1843 units, and between portable and mobile units to perform operations 1844 related to the improvement of traffic flow, traffic safety, and other 1845 intelligent transportation service applications in a variety of 1846 environments. DSRCS systems may also transmit status and 1847 instructional messages related to the units involve. [Ref. 47 CFR 1848 90.7 - Definitions] 1849 OBU (On-Board Unit): a term defined outside the IETF. An On-Board 1850 Unit is a DSRCS transceiver that is normally mounted in or on a 1851 vehicle, or which in some instances may be a portable unit. An OBU 1852 can be operational while a vehicle or person is either mobile or 1853 stationary. The OBUs receive and contend for time to transmit on one 1854 or more radio frequency (RF) channels. Except where specifically 1855 excluded, OBU operation is permitted wherever vehicle operation or 1856 human passage is permitted. The OBUs mounted in vehicles are 1857 licensed by rule under part 95 of the respective chapter and 1858 communicate with Roadside Units (RSUs) and other OBUs. Portable OBUs 1859 are also licensed by rule under part 95 of the respective chapter. 1860 OBU operations in the Unlicensed National Information Infrastructure 1861 (UNII) Bands follow the rules in those bands. - [CFR 90.7 - 1862 Definitions]. 1864 RSU (Road-Side Unit): a term defined outside of IETF. A Roadside 1865 Unit is a DSRC transceiver that is mounted along a road or pedestrian 1866 passageway. An RSU may also be mounted on a vehicle or is hand 1867 carried, but it may only operate when the vehicle or hand- carried 1868 unit is stationary. Furthermore, an RSU operating under the 1869 respectgive part is restricted to the location where it is licensed 1870 to operate. However, portable or hand-held RSUs are permitted to 1871 operate where they do not interfere with a site-licensed operation. 1872 A RSU broadcasts data to OBUs or exchanges data with OBUs in its 1873 communications zone. An RSU also provides channel assignments and 1874 operating instructions to OBUs in its communications zone, when 1875 required. - [CFR 90.7 - Definitions]. 1877 Appendix J. Neighbor Discovery (ND) Potential Issues in Wireless Links 1879 IPv6 Neighbor Discovery (IPv6 ND) [RFC4861][RFC4862] was designed for 1880 point-to-point and transit links such as Ethernet, with the 1881 expectation of a cheap and reliable support for multicast from the 1882 lower layer. Section 3.2 of RFC 4861 indicates that the operation on 1883 Shared Media and on non-broadcast multi-access (NBMA) networks 1884 require additional support, e.g., for Address Resolution (AR) and 1885 duplicate address detection (DAD), which depend on multicast. An 1886 infrastructureless radio network such as OCB shares properties with 1887 both Shared Media and NBMA networks, and then adds its own 1888 complexity, e.g., from movement and interference that allow only 1889 transient and non-transitive reachability between any set of peers. 1891 The uniqueness of an address within a scoped domain is a key pillar 1892 of IPv6 and the base for unicast IP communication. RFC 4861 details 1893 the DAD method to avoid that an address is duplicated. For a link 1894 local address, the scope is the link, whereas for a global address 1895 the scope is much larger. The underlying assumption for DAD to 1896 operate correctly is that the node that owns an IPv6 address can 1897 reach any other node within the scope at the time it claims its 1898 address, which is done by sending a NS multicast message, and can 1899 hear any future claim for that address by another party within the 1900 scope for the duration of the address ownership. 1902 In the case of OCB, there is a potentially a need to define a scope 1903 that is compatible with DAD, and that cannot be the set of nodes that 1904 a transmitter can reach at a particular time, because that set varies 1905 all the time and does not meet the DAD requirements for a link local 1906 address that could possibly be used anytime, anywhere. The generic 1907 expectation of a reliable multicast is not ensured, and the operation 1908 of DAD and AR (Address Resolution) as specificed by RFC 4861 cannot 1909 be guaranteed. Moreoever, multicast transmissions that rely on 1910 broadcast are not only unreliable but are also often detrimental to 1911 unicast traffic (see [draft-ietf-mboned-ieee802-mcast-problems]). 1913 Early experience indicates that it should be possible to exchange 1914 IPv6 packets over OCB while relying on IPv6 ND alone for DAD and AR 1915 (Address Resolution) in good conditions. However, this does not 1916 apply if TBD TBD TBD. In the absence of a correct DAD operation, a 1917 node that relies only on IPv6 ND for AR and DAD over OCB should 1918 ensure that the addresses that it uses are unique by means others 1919 than DAD. It must be noted that deriving an IPv6 address from a 1920 globally unique MAC address has this property but may yield privacy 1921 issues. 1923 RFC 8505 provides a more recent approach to IPv6 ND and in particular 1924 DAD. RFC 8505 is designed to fit wireless and otherwise constrained 1925 networks whereby multicast and/or continuous access to the medium may 1926 not be guaranteed. RFC 8505 Section 5.6 "Link-Local Addresses and 1927 Registration" indicates that the scope of uniqueness for a link local 1928 address is restricted to a pair of nodes that use it to communicate, 1929 and provides a method to assert the uniqueness and resolve the link- 1930 Layer address using a unicast exchange. 1932 RFC 8505 also enables a router (acting as a 6LR) to own a prefix and 1933 act as a registrar (acting as a 6LBR) for addresses within the 1934 associated subnet. A peer host (acting as a 6LN) registers an 1935 address derived from that prefix and can use it for the lifetime of 1936 the registration. The prefix is advertised as not onlink, which 1937 means that the 6LN uses the 6LR to relay its packets within the 1938 subnet, and participation to the subnet is constrained to the time of 1939 reachability to the 6LR. Note that RSU that provides internet 1940 connectivity MAY announce a default router preference [RFC 4191], 1941 whereas a car that does not provide that connectivity MUST NOT do so. 1942 This operation presents similarities with that of an access point, 1943 but at Layer-3. This is why RFC 8505 well-suited for wireless in 1944 general. 1946 Support of RFC 8505 is may be implemented on OCB. OCB nodes that 1947 support RFC 8505 would support the 6LN operation in order to act as a 1948 host, and may support the 6LR and 6LBR operations in order to act as 1949 a router and in particular own a prefix that can be used by RFC 1950 8505-compliant hosts for address autoconfiguration and registration. 1952 Authors' Addresses 1954 Alexandre Petrescu 1955 CEA, LIST 1956 CEA Saclay 1957 Gif-sur-Yvette , Ile-de-France 91190 1958 France 1960 Phone: +33169089223 1961 Email: Alexandre.Petrescu@cea.fr 1963 Nabil Benamar 1964 Moulay Ismail University 1965 Morocco 1967 Phone: +212670832236 1968 Email: n.benamar@est.umi.ac.ma 1970 Jerome Haerri 1971 Eurecom 1972 Sophia-Antipolis 06904 1973 France 1975 Phone: +33493008134 1976 Email: Jerome.Haerri@eurecom.fr 1978 Jong-Hyouk Lee 1979 Sangmyung University 1980 31, Sangmyeongdae-gil, Dongnam-gu 1981 Cheonan 31066 1982 Republic of Korea 1984 Email: jonghyouk@smu.ac.kr 1985 Thierry Ernst 1986 YoGoKo 1987 France 1989 Email: thierry.ernst@yogoko.fr