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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 11, 2019) is 1841 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. Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Missing Reference: 'RFC4862' is mentioned on line 1873, but not defined == Missing Reference: 'RFC 4191' is mentioned on line 1933, but not defined ** 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 ** Obsolete normative reference: RFC 7042 (Obsoleted by RFC 9542) ** Downref: Normative reference to an Informational RFC: RFC 7721 == Outdated reference: A later version (-15) exists of draft-ietf-mboned-ieee802-mcast-problems-04 Summary: 5 errors (**), 0 flaws (~~), 5 warnings (==), 2 comments (--). 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 13, 2019 Moulay Ismail University 6 J. Haerri 7 Eurecom 8 J. Lee 9 Sangmyung University 10 T. Ernst 11 YoGoKo 12 April 11, 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-38 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 13, 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 . . . . . . . . . . . . . . . . . . . . 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 . . . . . . . . . . . . . . . . . . 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 . . . . . . . . . . . . . . . . . . . . . . 27 90 Appendix C. Aspects introduced by the OCB mode to 802.11 . . . . 27 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 . . . . . . . . . . . . . 34 97 H.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . 35 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] and 124 [I-D.hinden-6man-rfc2464bis]. 126 o Exceptions due to the OCB nature of 802.11-OCB compared to 802.11. 127 This has impacts on security, privacy, subnet structure and 128 movement detection. For security and privacy recommendations see 129 Section 5 and Section 4.4. The subnet structure is described in 130 Section 4.6. The movement detection on OCB links is not described 131 in this document. 133 In the published literature, many documents describe aspects and 134 problems related to running IPv6 over 802.11-OCB: 135 [I-D.ietf-ipwave-vehicular-networking-survey]. 137 2. Terminology 139 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 140 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 141 "OPTIONAL" in this document are to be interpreted as described in BCP 142 14 [RFC2119] [RFC8174] when, and only when, they appear in all 143 capitals, as shown here. 145 IP-OBU (Internet Protocol On-Board Unit): an IP-OBU is a computer 146 situated in a vehicle such as an automobile, bicycle, or similar. It 147 has at least one IP interface that runs in mode OCB of 802.11, and 148 that has an "OBU" transceiver. See the definition of the term "OBU" 149 in section Appendix I. 151 IP-RSU (IP Road-Side Unit): an IP-RSU is situated along the road. It 152 has at least two distinct IP-enabled interfaces; the wireless PHY/MAC 153 layer of at least one of its IP-enabled interfaces is configured to 154 operate in 802.11-OCB mode. An IP-RSU communicates with the IP-OBU 155 in the vehicle over 802.11 wireless link operating in OCB mode. An 156 IP-RSU is similar to an Access Network Router (ANR) defined in 157 [RFC3753], and a Wireless Termination Point (WTP) defined in 158 [RFC5415]. 160 OCB (outside the context of a basic service set - BSS): A mode of 161 operation in which a STA is not a member of a BSS and does not 162 utilize IEEE Std 802.11 authentication, association, or data 163 confidentiality. 165 802.11-OCB: mode specified in IEEE Std 802.11-2016 when the MIB 166 attribute dot11OCBActivited is true. Note: compliance with standards 167 and regulations set in different countries when using the 5.9GHz 168 frequency band is required. 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 4. IPv6 over 802.11-OCB 188 4.1. Maximum Transmission Unit (MTU) 190 The default MTU for IP packets on 802.11-OCB MUST be 1500 octets. It 191 is the same value as IPv6 packets on Ethernet links, as specified in 192 [RFC2464]. This value of the MTU respects the recommendation that 193 every link on the Internet must have a minimum MTU of 1280 octets 194 (stated in [RFC8200], and the recommendations therein, especially 195 with respect to fragmentation). 197 4.2. Frame Format 199 IP packets MUST be transmitted over 802.11-OCB media as QoS Data 200 frames whose format is specified in IEEE 802.11(TM) -2016 201 [IEEE-802.11-2016]. 203 The IPv6 packet transmitted on 802.11-OCB MUST be immediately 204 preceded by a Logical Link Control (LLC) header and an 802.11 header. 205 In the LLC header, and in accordance with the EtherType Protocol 206 Discrimination (EPD, see Appendix E), the value of the Type field 207 MUST be set to 0x86DD (IPv6). In the 802.11 header, the value of the 208 Subtype sub-field in the Frame Control field MUST be set to 8 (i.e. 209 'QoS Data'); the value of the Traffic Identifier (TID) sub-field of 210 the QoS Control field of the 802.11 header MUST be set to binary 001 211 (i.e. User Priority 'Background', QoS Access Category 'AC_BK'). 213 To simplify the Application Programming Interface (API) between the 214 operating system and the 802.11-OCB media, device drivers MAY 215 implement an Ethernet Adaptation Layer that translates Ethernet II 216 frames to the 802.11 format and vice versa. An Ethernet Adaptation 217 Layer is described in Section 4.2.1. 219 4.2.1. Ethernet Adaptation Layer 221 An 'adaptation' layer is inserted between a MAC layer and the 222 Networking layer. This is used to transform some parameters between 223 their form expected by the IP stack and the form provided by the MAC 224 layer. 226 An Ethernet Adaptation Layer makes an 802.11 MAC look to IP 227 Networking layer as a more traditional Ethernet layer. At reception, 228 this layer takes as input the IEEE 802.11 header and the Logical-Link 229 Layer Control Header and produces an Ethernet II Header. At sending, 230 the reverse operation is performed. 232 The operation of the Ethernet Adaptation Layer is depicted by the 233 double arrow in Figure 1. 235 +------------------+------------+-------------+---------+-----------+ 236 | 802.11 header | LLC Header | IPv6 Header | Payload |.11 Trailer| 237 +------------------+------------+-------------+---------+-----------+ 238 \ / \ / 239 --------------------------- -------- 240 \---------------------------------------------/ 241 ^ 242 | 243 802.11-to-Ethernet Adaptation Layer 244 | 245 v 246 +---------------------+-------------+---------+ 247 | Ethernet II Header | IPv6 Header | Payload | 248 +---------------------+-------------+---------+ 250 Figure 1: Operation of the Ethernet Adaptation Layer 252 The Receiver and Transmitter Address fields in the 802.11 header MUST 253 contain the same values as the Destination and the Source Address 254 fields in the Ethernet II Header, respectively. The value of the 255 Type field in the LLC Header MUST be the same as the value of the 256 Type field in the Ethernet II Header. That value MUST be set to 257 0x86DD (IPv6). 259 The ".11 Trailer" contains solely a 4-byte Frame Check Sequence. 261 The placement of IPv6 networking layer on Ethernet Adaptation Layer 262 is illustrated in Figure 2. 264 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 265 | IPv6 | 266 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 267 | Ethernet Adaptation Layer | 268 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 269 | 802.11 MAC | 270 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 271 | 802.11 PHY | 272 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 274 Figure 2: Ethernet Adaptation Layer stacked with other layers 276 (in the above figure, a 802.11 profile is represented; this is used 277 also for 802.11-OCB profile.) 279 4.3. Link-Local Addresses 281 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 282 MAY be assigned to an 802.11-OCB interface. Among these types of 283 addresses only the IPv6 link-local addresses MAY be formed using an 284 EUI-64 identifier, in particular during transition time. 286 If the IPv6 link-local address is formed using an EUI-64 identifier, 287 then the mechanism of forming that address is the same mechanism as 288 used to form an IPv6 link-local address on Ethernet links. This 289 mechanism is described in section 5 of [RFC2464]. 291 4.4. Stateless Autoconfiguration 293 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 294 MAY be assigned to an 802.11-OCB interface. This section describes 295 the formation of Interface Identifiers for IPv6 addresses of type 296 'Global' or 'Unique Local'. For Interface Identifiers for IPv6 297 address of type 'Link-Local' see Section 4.3. 299 The Interface Identifier for an 802.11-OCB interface is formed using 300 the same rules as the Interface Identifier for an Ethernet interface; 301 the RECOMMENDED method for forming stable Interface Identifiers 302 (IIDs) is described in [RFC8064]. The method of forming IIDs 303 described in section 4 of [RFC2464] MAY be used during transition 304 time, in particular for IPv6 link-local addresses. 306 The bits in the Interface Identifier have no generic meaning and the 307 identifier should be treated as an opaque value. The bits 308 'Universal' and 'Group' in the identifier of an 802.11-OCB interface 309 are significant, as this is an IEEE link-layer address. The details 310 of this significance are described in [RFC7136]. 312 Semantically opaque Interface Identifiers, instead of meaningful 313 Interface Identifiers derived from a valid and meaningful MAC address 314 ([RFC2464], section 4), help avoid certain privacy risks (see the 315 risks mentioned in Section 5.1.1). If semantically opaque Interface 316 Identifiers are needed, they MAY be generated using the method for 317 generating semantically opaque Interface Identifiers with IPv6 318 Stateless Address Autoconfiguration given in [RFC7217]. Typically, 319 an opaque Interface Identifier is formed starting from identifiers 320 different than the MAC addresses, and from cryptographically strong 321 material. Thus, privacy sensitive information is absent from 322 Interface IDs, because it is impossible to calculate back the initial 323 value from which the Interface ID was first generated (intuitively, 324 it is as hard as mentally finding the square root of a number, and as 325 impossible as trying to use computers to identify quickly whether a 326 large number is prime). 328 Some applications that use IPv6 packets on 802.11-OCB links (among 329 other link types) may benefit from IPv6 addresses whose Interface 330 Identifiers don't change too often. It is RECOMMENDED to use the 331 mechanisms described in RFC 7217 to permit the use of Stable 332 Interface Identifiers that do not change within one subnet prefix. A 333 possible source for the Net-Iface Parameter is a virtual interface 334 name, or logical interface name, that is decided by a local 335 administrator. 337 4.5. Address Mapping 339 Unicast and multicast address mapping MUST follow the procedures 340 specified for Ethernet interfaces in sections 6 and 7 of [RFC2464]. 342 4.5.1. Address Mapping -- Unicast 344 The procedure for mapping IPv6 unicast addresses into Ethernet link- 345 layer addresses is described in [RFC4861]. 347 4.5.2. Address Mapping -- Multicast 349 The multicast address mapping is performed according to the method 350 specified in section 7 of [RFC2464]. The meaning of the value "3333" 351 mentioned in that section 7 of [RFC2464] is defined in section 2.3.1 352 of [RFC7042]. 354 Transmitting IPv6 packets to multicast destinations over 802.11 links 355 proved to have some performance issues 356 [I-D.ietf-mboned-ieee802-mcast-problems]. These issues may be 357 exacerbated in OCB mode. Solutions for these problems SHOULD 358 consider the OCB mode of operation. 360 4.6. Subnet Structure 362 A subnet is formed by the external 802.11-OCB interfaces of vehicles 363 that are in close range (not by their in-vehicle interfaces). This 364 subnet MUST use at least the link-local prefix and the interfaces 365 MUST be assigned IPv6 address(es) of type link-local. 367 The structure of this subnet is ephemeral, in that it is strongly 368 influenced by the mobility of vehicles: the hidden terminal effects 369 appear; the 802.11 networks in OCB mode may be considered as 'ad-hoc' 370 networks with an addressing model as described in [RFC5889]. On 371 another hand, the structure of the internal subnets in each car is 372 relatively stable. 374 As recommended in [RFC5889], when the timing requirements are very 375 strict (e.g. fast drive through IP-RSU coverage), no on-link subnet 376 prefix should be configured on an 802.11-OCB interface. In such 377 cases, the exclusive use of IPv6 link-local addresses is RECOMMENDED. 379 Additionally, even if the timing requirements are not very strict 380 (e.g. the moving subnet formed by two following vehicles is stable, a 381 fixed IP-RSU is absent), the subnet is disconnected from the Internet 382 (a default route is absent), and the addressing peers are equally 383 qualified (impossible to determine that some vehicle owns and 384 distributes addresses to others) the use of link-local addresses is 385 RECOMMENDED. 387 The baseline Neighbor Discovery protocol (ND) [RFC4861] MUST be used 388 over 802.11-OCB links. Transmitting ND packets may prove to have 389 some performance issues. These issues may be exacerbated in OCB 390 mode. Solutions for these problems SHOULD consider the OCB mode of 391 operation. The best of current knowledge indicates the kinds of 392 issues that may arise with ND in OCB mode; they are described in 393 Appendix J. 395 Protocols like Mobile IPv6 [RFC6275] and DNAv6 [RFC6059], which 396 depend on timely movement detection, might need additional tuning 397 work to handle the lack of link-layer notifications during handover. 398 This is for further study. 400 5. Security Considerations 402 Any security mechanism at the IP layer or above that may be carried 403 out for the general case of IPv6 may also be carried out for IPv6 404 operating over 802.11-OCB. 406 The OCB operation is stripped off of all existing 802.11 link-layer 407 security mechanisms. There is no encryption applied below the 408 network layer running on 802.11-OCB. At application layer, the IEEE 409 1609.2 document [IEEE-1609.2] does provide security services for 410 certain applications to use; application-layer mechanisms are out-of- 411 scope of this document. On another hand, a security mechanism 412 provided at networking layer, such as IPsec [RFC4301], may provide 413 data security protection to a wider range of applications. 415 802.11-OCB does not provide any cryptographic protection, because it 416 operates outside the context of a BSS (no Association Request/ 417 Response, no Challenge messages). Any attacker can therefore just 418 sit in the near range of vehicles, sniff the network (just set the 419 interface card's frequency to the proper range) and perform attacks 420 without needing to physically break any wall. Such a link is less 421 protected than commonly used links (wired link or protected 802.11). 423 The potential attack vectors are: MAC address spoofing, IP address 424 and session hijacking, and privacy violation Section 5.1. 426 Within the IPsec Security Architecture [RFC4301], the IPsec AH and 427 ESP headers [RFC4302] and [RFC4303] respectively, its multicast 428 extensions [RFC5374], HTTPS [RFC2818] and SeND [RFC3971] protocols 429 can be used to protect communications. Further, the assistance of 430 proper Public Key Infrastructure (PKI) protocols [RFC4210] is 431 necessary to establish credentials. More IETF protocols are 432 available in the toolbox of the IP security protocol designer. 433 Certain ETSI protocols related to security protocols in Intelligent 434 Transportation Systems are described in [ETSI-sec-archi]. 436 5.1. Privacy Considerations 438 As with all Ethernet and 802.11 interface identifiers ([RFC7721]), 439 the identifier of an 802.11-OCB interface may involve privacy, MAC 440 address spoofing and IP address hijacking risks. A vehicle embarking 441 an IP-OBU whose egress interface is 802.11-OCB may expose itself to 442 eavesdropping and subsequent correlation of data; this may reveal 443 data considered private by the vehicle owner; there is a risk of 444 being tracked. In outdoors public environments, where vehicles 445 typically circulate, the privacy risks are more important than in 446 indoors settings. It is highly likely that attacker sniffers are 447 deployed along routes which listen for IEEE frames, including IP 448 packets, of vehicles passing by. For this reason, in the 802.11-OCB 449 deployments, there is a strong necessity to use protection tools such 450 as dynamically changing MAC addresses Section 5.2, semantically 451 opaque Interface Identifiers and stable Interface Identifiers 452 Section 4.4. This may help mitigate privacy risks to a certain 453 level. 455 5.1.1. Privacy Risks of Meaningful info in Interface IDs 457 The privacy risks of using MAC addresses displayed in Interface 458 Identifiers are important. The IPv6 packets can be captured easily 459 in the Internet and on-link in public roads. For this reason, an 460 attacker may realize many attacks on privacy. One such attack on 461 802.11-OCB is to capture, store and correlate Company ID information 462 present in MAC addresses of many cars (e.g. listen for Router 463 Advertisements, or other IPv6 application data packets, and record 464 the value of the source address in these packets). Further 465 correlation of this information with other data captured by other 466 means, or other visual information (car color, others) MAY constitute 467 privacy risks. 469 5.2. MAC Address and Interface ID Generation 471 In 802.11-OCB networks, the MAC addresses MAY change during well 472 defined renumbering events. In the moment the MAC address is changed 473 on an 802.11-OCB interface all the Interface Identifiers of IPv6 474 addresses assigned to that interface MUST change. 476 The policy dictating when the MAC address is changed on the 477 802.11-OCB interface is to-be-determined. For more information on 478 the motivation of this policy please refer to the privacy discussion 479 in Appendix C. 481 A 'randomized' MAC address has the following characteristics: 483 o Bit "Local/Global" set to "locally admninistered". 485 o Bit "Unicast/Multicast" set to "Unicast". 487 o The 46 remaining bits are set to a random value, using a random 488 number generator that meets the requirements of [RFC4086]. 490 To meet the randomization requirements for the 46 remaining bits, a 491 hash function may be used. For example, the SHA256 hash function may 492 be used with input a 256 bit local secret, the 'nominal' MAC Address 493 of the interface, and a representation of the date and time of the 494 renumbering event. 496 A randomized Interface ID has the same characteristics of a 497 randomized MAC address, except the length in bits. A MAC address 498 SHOULD be of length 48 decimal. An Interface ID SHOULD be of length 499 64 decimal for all types of IPv6 addresses. In the particular case 500 of IPv6 link-local addresses, the length of the Interface ID MAY be 501 118 decimal. 503 5.3. Pseudonym Handling 505 The demand for privacy protection of vehicles' and drivers' 506 identities, which could be granted by using a pseudonym or alias 507 identity at the same time, may hamper the required confidentiality of 508 messages and trust between participants - especially in safety 509 critical vehicular communication. 511 o Particular challenges arise when the pseudonymization mechanism 512 used relies on (randomized) re-addressing. 514 o A proper pseudonymization tool operated by a trusted third party 515 may be needed to ensure both aspects simultaneously (privacy 516 protection on one hand and trust between participants on another 517 hand). 519 o This is discussed in Section 4.4 and Section 5 of this document. 521 o Pseudonymity is also discussed in 522 [I-D.ietf-ipwave-vehicular-networking-survey] in its sections 523 4.2.4 and 5.1.2. 525 6. IANA Considerations 527 No request to IANA. 529 7. Contributors 531 Christian Huitema, Tony Li. 533 Romain Kuntz contributed extensively about IPv6 handovers between 534 links running outside the context of a BSS (802.11-OCB links). 536 Tim Leinmueller contributed the idea of the use of IPv6 over 537 802.11-OCB for distribution of certificates. 539 Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey 540 Voronov provided significant feedback on the experience of using IP 541 messages over 802.11-OCB in initial trials. 543 Michelle Wetterwald contributed extensively the MTU discussion, 544 offered the ETSI ITS perspective, and reviewed other parts of the 545 document. 547 8. Acknowledgements 549 The authors would like to thank Witold Klaudel, Ryuji Wakikawa, 550 Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan 551 Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray 552 Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, 553 Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne, 554 Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark, 555 Bob Moskowitz, Andrew Dryden, Georg Mayer, Dorothy Stanley, Sandra 556 Cespedes, Mariano Falcitelli, Sri Gundavelli, Abdussalam Baryun, 557 Margaret Cullen, Erik Kline, Carlos Jesus Bernardos Cano, Ronald in 558 't Velt, Katrin Sjoberg, Roland Bless, Tijink Jasja, Kevin Smith, 559 Brian Carpenter, Julian Reschke, Mikael Abrahamsson, Dirk von Hugo, 560 Lorenzo Colitti, Pascal Thubert, Ole Troan, Jinmei Tatuya and William 561 Whyte. Their valuable comments clarified particular issues and 562 generally helped to improve the document. 564 Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB 565 drivers for linux and described how. 567 For the multicast discussion, the authors would like to thank Owen 568 DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and 569 participants to discussions in network working groups. 571 The authors would like to thank participants to the Birds-of- 572 a-Feather "Intelligent Transportation Systems" meetings held at IETF 573 in 2016. 575 Human Rights Protocol Considerations review by Amelia Andersdotter. 577 9. References 579 9.1. Normative References 581 [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission 582 of IP datagrams over IEEE 802 networks", STD 43, RFC 1042, 583 DOI 10.17487/RFC1042, February 1988, 584 . 586 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 587 Requirement Levels", BCP 14, RFC 2119, 588 DOI 10.17487/RFC2119, March 1997, 589 . 591 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 592 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 593 . 595 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 596 DOI 10.17487/RFC2818, May 2000, 597 . 599 [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related 600 Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, 601 . 603 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 604 "SEcure Neighbor Discovery (SEND)", RFC 3971, 605 DOI 10.17487/RFC3971, March 2005, 606 . 608 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 609 "Randomness Requirements for Security", BCP 106, RFC 4086, 610 DOI 10.17487/RFC4086, June 2005, 611 . 613 [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast 614 Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005, 615 . 617 [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, 618 "Internet X.509 Public Key Infrastructure Certificate 619 Management Protocol (CMP)", RFC 4210, 620 DOI 10.17487/RFC4210, September 2005, 621 . 623 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 624 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 625 2006, . 627 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 628 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 629 December 2005, . 631 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 632 DOI 10.17487/RFC4302, December 2005, 633 . 635 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 636 RFC 4303, DOI 10.17487/RFC4303, December 2005, 637 . 639 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 640 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 641 DOI 10.17487/RFC4861, September 2007, 642 . 644 [RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast 645 Extensions to the Security Architecture for the Internet 646 Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008, 647 . 649 [RFC5415] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, 650 Ed., "Control And Provisioning of Wireless Access Points 651 (CAPWAP) Protocol Specification", RFC 5415, 652 DOI 10.17487/RFC5415, March 2009, 653 . 655 [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing 656 Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889, 657 September 2010, . 659 [RFC6059] Krishnan, S. and G. Daley, "Simple Procedures for 660 Detecting Network Attachment in IPv6", RFC 6059, 661 DOI 10.17487/RFC6059, November 2010, 662 . 664 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 665 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 666 2011, . 668 [RFC7042] Eastlake 3rd, D. and J. Abley, "IANA Considerations and 669 IETF Protocol and Documentation Usage for IEEE 802 670 Parameters", BCP 141, RFC 7042, DOI 10.17487/RFC7042, 671 October 2013, . 673 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 674 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 675 February 2014, . 677 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 678 Interface Identifiers with IPv6 Stateless Address 679 Autoconfiguration (SLAAC)", RFC 7217, 680 DOI 10.17487/RFC7217, April 2014, 681 . 683 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 684 Considerations for IPv6 Address Generation Mechanisms", 685 RFC 7721, DOI 10.17487/RFC7721, March 2016, 686 . 688 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 689 "Recommendation on Stable IPv6 Interface Identifiers", 690 RFC 8064, DOI 10.17487/RFC8064, February 2017, 691 . 693 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 694 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 695 May 2017, . 697 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 698 (IPv6) Specification", STD 86, RFC 8200, 699 DOI 10.17487/RFC8200, July 2017, 700 . 702 9.2. Informative References 704 [ETSI-sec-archi] 705 "ETSI TS 102 940 V1.2.1 (2016-11), ETSI Technical 706 Specification, Intelligent Transport Systems (ITS); 707 Security; ITS communications security architecture and 708 security management, November 2016. Downloaded on 709 September 9th, 2017, freely available from ETSI website at 710 URL http://www.etsi.org/deliver/ 711 etsi_ts/102900_102999/102940/01.02.01_60/ 712 ts_102940v010201p.pdf". 714 [I-D.hinden-6man-rfc2464bis] 715 Crawford, M. and R. Hinden, "Transmission of IPv6 Packets 716 over Ethernet Networks", draft-hinden-6man-rfc2464bis-02 717 (work in progress), March 2017. 719 [I-D.ietf-ipwave-vehicular-networking-survey] 720 Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M. 721 Wetterwald, "Survey on IP-based Vehicular Networking for 722 Intelligent Transportation Systems", draft-ietf-ipwave- 723 vehicular-networking-survey-00 (work in progress), July 724 2017. 726 [I-D.ietf-mboned-ieee802-mcast-problems] 727 Perkins, C., McBride, M., Stanley, D., Kumari, W., and J. 728 Zuniga, "Multicast Considerations over IEEE 802 Wireless 729 Media", draft-ietf-mboned-ieee802-mcast-problems-04 (work 730 in progress), November 2018. 732 [IEEE-1609.2] 733 "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access 734 in Vehicular Environments (WAVE) -- Security Services for 735 Applications and Management Messages. Example URL 736 http://ieeexplore.ieee.org/document/7426684/ accessed on 737 August 17th, 2017.". 739 [IEEE-1609.3] 740 "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access 741 in Vehicular Environments (WAVE) -- Networking Services. 742 Example URL http://ieeexplore.ieee.org/document/7458115/ 743 accessed on August 17th, 2017.". 745 [IEEE-1609.4] 746 "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access 747 in Vehicular Environments (WAVE) -- Multi-Channel 748 Operation. Example URL 749 http://ieeexplore.ieee.org/document/7435228/ accessed on 750 August 17th, 2017.". 752 [IEEE-802.11-2016] 753 "IEEE Standard 802.11-2016 - IEEE Standard for Information 754 Technology - Telecommunications and information exchange 755 between systems Local and metropolitan area networks - 756 Specific requirements - Part 11: Wireless LAN Medium 757 Access Control (MAC) and Physical Layer (PHY) 758 Specifications. Status - Active Standard. Description 759 retrieved freely; the document itself is also freely 760 available, but with some difficulty (requires 761 registration); description and document retrieved on April 762 8th, 2019, starting from URL 763 https://standards.ieee.org/findstds/ 764 standard/802.11-2016.html". 766 [IEEE-802.11p-2010] 767 "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information 768 Technology - Telecommunications and information exchange 769 between systems - Local and metropolitan area networks - 770 Specific requirements, Part 11: Wireless LAN Medium Access 771 Control (MAC) and Physical Layer (PHY) Specifications, 772 Amendment 6: Wireless Access in Vehicular Environments; 773 document freely available at URL 774 http://standards.ieee.org/getieee802/ 775 download/802.11p-2010.pdf retrieved on September 20th, 776 2013.". 778 Appendix A. ChangeLog 780 The changes are listed in reverse chronological order, most recent 781 changes appearing at the top of the list. 783 -38: removed the word "fe80::/10". 785 -37: added a section about issues on ND wireless; added the qualifier 786 'baseline' to using ND on 802.11-OCB; improved the description of the 787 reference to 802.11-2016 document, with a qualifier about the 788 difficulty of accessing it, even though it is free. 790 -36: removed a phrase about the IID formation and MAC generation, but 791 left in the section 5.2 that describes how it happens. 793 -35: addressing the the intarea review: clarified a small apparent 794 contradiction between two parts of text that use the old MAC-based 795 IIDs (clarified by using qualifiers from each other: transition time, 796 and ll addresses); sequenced closer the LL and Stateless Autoconf 797 sections, instead of spacing them; shortened the paragraph of Opaque 798 IIDs; moved the privacy risks of in-clear IIDs in the security 799 section; removed a short phrase duplicating the idea of privacy 800 risks; added third time a reference to the 802.11-2016 document; used 801 'the hidden terminal' text; updated the Terminology section with new 802 BCP-14 text 'MUST' to include RFC8174. 804 -33: substituted 'movement detection' for 'handover behaviour' in 805 introductory text; removed redundant phrase referring to Security 806 Considerations section; removed the phrase about forming mechanisms 807 being left out, as IP is not much concerned about L2 forming; moved 808 the Pseudonym section from main section to end of Security 809 Considerations section (and clarified 'concurrently'); capitalized 810 SHOULD consider OCB in WiFi multicast problems, and referred to more 811 recent I-D on topic; removed several phrases in a paragraph about 812 oui.txt and MAC presence in IPv6 address, as they are well known 813 info, but clarified the example of privacy risk of Company ID in MAC 814 addresses in public roads; clarified that ND MUST be used over 815 802.11-OCB. 817 -32: significantly shortened the relevant ND/OCB paragraph. It now 818 just states ND is used over OCB, w/o detailing. 820 -31: filled in the section titled "Pseudonym Handling"; removed a 821 'MAY NOT' phrase about possibility of having other prefix than the LL 822 on the link between cars; shortened and improved the paragraph about 823 Mobile IPv6, now with DNAv6; improved the ND text about ND 824 retransmissions with relationship to packet loss; changed the title 825 of an appendix from 'EPD' to 'Protocol Layering'; improved the 826 'Aspects introduced by OCB' appendix with a few phrases about the 827 channel use and references. 829 -30: a clarification on the reliability of ND over OCB and over 830 802.11. 832 -29: 834 o 836 -28: 838 o Created a new section 'Pseudonym Handling'. 840 o removed the 'Vehicle ID' appendix. 842 o improved the address generation from random MAC address. 844 o shortened Term IP-RSU definition. 846 o removed refs to two detail Clauses in IEEE documents, kept just 847 these latter. 849 -27: part 1 of addressing Human Rights review from IRTF. Removed 850 appendices F.2 and F.3. Shortened definition of IP-RSU. Removed 851 reference to 1609.4. A few other small changes, see diff. 853 -26: moved text from SLAAC section and from Design Considerations 854 appendix about privacy into a new Privacy Condiderations subsection 855 of the Security section; reformulated the SLAAC and IID sections to 856 stress only LLs can use EUI-64; removed the "GeoIP" wireshark 857 explanation; reformulated SLAAC and LL sections; added brief mention 858 of need of use LLs; clarified text about MAC address changes; dropped 859 pseudonym discussion; changed title of section describing examples of 860 packet formats. 862 -25: added a reference to 'IEEE Management Information Base', instead 863 of just 'Management Information Base'; added ref to further 864 appendices in the introductory phrases; improved text for IID 865 formation for SLAAC, inserting recommendation for RFC8064 before 866 RFC2464. 868 From draft-ietf-ipwave-ipv6-over-80211ocb-23 to draft-ietf-ipwave- 869 ipv6-over-80211ocb-24 871 o Nit: wrote "IPWAVE Working Group" on the front page, instead of 872 "Network Working Group". 874 o Addressed the comments on 6MAN: replaced a sentence about ND 875 problem with "is used over 802.11-OCB". 877 From draft-ietf-ipwave-ipv6-over-80211ocb-22 to draft-ietf-ipwave- 878 ipv6-over-80211ocb-23 880 o No content modifications, but check the entire draft chain on 881 IPv6-only: xml2rfc, submission on tools.ietf.org and datatracker. 883 From draft-ietf-ipwave-ipv6-over-80211ocb-21 to draft-ietf-ipwave- 884 ipv6-over-80211ocb-22 886 o Corrected typo, use dash in "802.11-OCB" instead of space. 888 o Improved the Frame Format section: MUST use QoSData, specify the 889 values within; clarified the Ethernet Adaptation Layer text. 891 From draft-ietf-ipwave-ipv6-over-80211ocb-20 to draft-ietf-ipwave- 892 ipv6-over-80211ocb-21 894 o Corrected a few nits and added names in Acknowledgments section. 896 o Removed unused reference to old Internet Draft tsvwg about QoS. 898 From draft-ietf-ipwave-ipv6-over-80211ocb-19 to draft-ietf-ipwave- 899 ipv6-over-80211ocb-20 901 o Reduced the definition of term "802.11-OCB". 903 o Left out of this specification which 802.11 header to use to 904 transmit IP packets in OCB mode (QoS Data header, Data header, or 905 any other). 907 o Added 'MUST' use an Ethernet Adaptation Layer, instead of 'is 908 using' an Ethernet Adaptation Layer. 910 From draft-ietf-ipwave-ipv6-over-80211ocb-18 to draft-ietf-ipwave- 911 ipv6-over-80211ocb-19 913 o Removed the text about fragmentation. 915 o Removed the mentioning of WSMP and GeoNetworking. 917 o Removed the explanation of the binary representation of the 918 EtherType. 920 o Rendered normative the paragraph about unicast and multicast 921 address mapping. 923 o Removed paragraph about addressing model, subnet structure and 924 easiness of using LLs. 926 o Clarified the Type/Subtype field in the 802.11 Header. 928 o Used RECOMMENDED instead of recommended, for the stable interface 929 identifiers. 931 From draft-ietf-ipwave-ipv6-over-80211ocb-17 to draft-ietf-ipwave- 932 ipv6-over-80211ocb-18 934 o Improved the MTU and fragmentation paragraph. 936 From draft-ietf-ipwave-ipv6-over-80211ocb-16 to draft-ietf-ipwave- 937 ipv6-over-80211ocb-17 939 o Susbtituted "MUST be increased" to "is increased" in the MTU 940 section, about fragmentation. 942 From draft-ietf-ipwave-ipv6-over-80211ocb-15 to draft-ietf-ipwave- 943 ipv6-over-80211ocb-16 944 o Removed the definition of the 'WiFi' term and its occurences. 945 Clarified a phrase that used it in Appendix C "Aspects introduced 946 by the OCB mode to 802.11". 948 o Added more normative words: MUST be 0x86DD, MUST fragment if size 949 larger than MTU, Sequence number in 802.11 Data header MUST be 950 increased. 952 From draft-ietf-ipwave-ipv6-over-80211ocb-14 to draft-ietf-ipwave- 953 ipv6-over-80211ocb-15 955 o Added normative term MUST in two places in section "Ethernet 956 Adaptation Layer". 958 From draft-ietf-ipwave-ipv6-over-80211ocb-13 to draft-ietf-ipwave- 959 ipv6-over-80211ocb-14 961 o Created a new Appendix titled "Extra Terminology" that contains 962 terms DSRC, DSRCS, OBU, RSU as defined outside IETF. Some of them 963 are used in the main Terminology section. 965 o Added two paragraphs explaining that ND and Mobile IPv6 have 966 problems working over 802.11-OCB, yet their adaptations is not 967 specified in this document. 969 From draft-ietf-ipwave-ipv6-over-80211ocb-12 to draft-ietf-ipwave- 970 ipv6-over-80211ocb-13 972 o Substituted "IP-OBU" for "OBRU", and "IP-RSU" for "RSRU" 973 throughout and improved OBU-related definitions in the Terminology 974 section. 976 From draft-ietf-ipwave-ipv6-over-80211ocb-11 to draft-ietf-ipwave- 977 ipv6-over-80211ocb-12 979 o Improved the appendix about "MAC Address Generation" by expressing 980 the technique to be an optional suggestion, not a mandatory 981 mechanism. 983 From draft-ietf-ipwave-ipv6-over-80211ocb-10 to draft-ietf-ipwave- 984 ipv6-over-80211ocb-11 986 o Shortened the paragraph on forming/terminating 802.11-OCB links. 988 o Moved the draft tsvwg-ieee-802-11 to Informative References. 990 From draft-ietf-ipwave-ipv6-over-80211ocb-09 to draft-ietf-ipwave- 991 ipv6-over-80211ocb-10 992 o Removed text requesting a new Group ID for multicast for OCB. 994 o Added a clarification of the meaning of value "3333" in the 995 section Address Mapping -- Multicast. 997 o Added note clarifying that in Europe the regional authority is not 998 ETSI, but "ECC/CEPT based on ENs from ETSI". 1000 o Added note stating that the manner in which two STAtions set their 1001 communication channel is not described in this document. 1003 o Added a time qualifier to state that the "each node is represented 1004 uniquely at a certain point in time." 1006 o Removed text "This section may need to be moved" (the "Reliability 1007 Requirements" section). This section stays there at this time. 1009 o In the term definition "802.11-OCB" added a note stating that "any 1010 implementation should comply with standards and regulations set in 1011 the different countries for using that frequency band." 1013 o In the RSU term definition, added a sentence explaining the 1014 difference between RSU and RSRU: in terms of number of interfaces 1015 and IP forwarding. 1017 o Replaced "with at least two IP interfaces" with "with at least two 1018 real or virtual IP interfaces". 1020 o Added a term in the Terminology for "OBU". However the definition 1021 is left empty, as this term is defined outside IETF. 1023 o Added a clarification that it is an OBU or an OBRU in this phrase 1024 "A vehicle embarking an OBU or an OBRU". 1026 o Checked the entire document for a consistent use of terms OBU and 1027 OBRU. 1029 o Added note saying that "'p' is a letter identifying the 1030 Ammendment". 1032 o Substituted lower case for capitals SHALL or MUST in the 1033 Appendices. 1035 o Added reference to RFC7042, helpful in the 3333 explanation. 1036 Removed reference to individual submission draft-petrescu-its- 1037 scenario-reqs and added reference to draft-ietf-ipwave-vehicular- 1038 networking-survey. 1040 o Added figure captions, figure numbers, and references to figure 1041 numbers instead of 'below'. Replaced "section Section" with 1042 "section" throughout. 1044 o Minor typographical errors. 1046 From draft-ietf-ipwave-ipv6-over-80211ocb-08 to draft-ietf-ipwave- 1047 ipv6-over-80211ocb-09 1049 o Significantly shortened the Address Mapping sections, by text 1050 copied from RFC2464, and rather referring to it. 1052 o Moved the EPD description to an Appendix on its own. 1054 o Shortened the Introduction and the Abstract. 1056 o Moved the tutorial section of OCB mode introduced to .11, into an 1057 appendix. 1059 o Removed the statement that suggests that for routing purposes a 1060 prefix exchange mechanism could be needed. 1062 o Removed refs to RFC3963, RFC4429 and RFC6775; these are about ND, 1063 MIP/NEMO and oDAD; they were referred in the handover discussion 1064 section, which is out. 1066 o Updated a reference from individual submission to now a WG item in 1067 IPWAVE: the survey document. 1069 o Added term definition for WiFi. 1071 o Updated the authorship and expanded the Contributors section. 1073 o Corrected typographical errors. 1075 From draft-ietf-ipwave-ipv6-over-80211ocb-07 to draft-ietf-ipwave- 1076 ipv6-over-80211ocb-08 1078 o Removed the per-channel IPv6 prohibition text. 1080 o Corrected typographical errors. 1082 From draft-ietf-ipwave-ipv6-over-80211ocb-06 to draft-ietf-ipwave- 1083 ipv6-over-80211ocb-07 1085 o Added new terms: OBRU and RSRU ('R' for Router). Refined the 1086 existing terms RSU and OBU, which are no longer used throughout 1087 the document. 1089 o Improved definition of term "802.11-OCB". 1091 o Clarified that OCB does not "strip" security, but that the 1092 operation in OCB mode is "stripped off of all .11 security". 1094 o Clarified that theoretical OCB bandwidth speed is 54mbits, but 1095 that a commonly observed bandwidth in IP-over-OCB is 12mbit/s. 1097 o Corrected typographical errors, and improved some phrasing. 1099 From draft-ietf-ipwave-ipv6-over-80211ocb-05 to draft-ietf-ipwave- 1100 ipv6-over-80211ocb-06 1102 o Updated references of 802.11-OCB document from -2012 to the IEEE 1103 802.11-2016. 1105 o In the LL address section, and in SLAAC section, added references 1106 to 7217 opaque IIDs and 8064 stable IIDs. 1108 From draft-ietf-ipwave-ipv6-over-80211ocb-04 to draft-ietf-ipwave- 1109 ipv6-over-80211ocb-05 1111 o Lengthened the title and cleanded the abstract. 1113 o Added text suggesting LLs may be easy to use on OCB, rather than 1114 GUAs based on received prefix. 1116 o Added the risks of spoofing and hijacking. 1118 o Removed the text speculation on adoption of the TSA message. 1120 o Clarified that the ND protocol is used. 1122 o Clarified what it means "No association needed". 1124 o Added some text about how two STAs discover each other. 1126 o Added mention of external (OCB) and internal network (stable), in 1127 the subnet structure section. 1129 o Added phrase explaining that both .11 Data and .11 QoS Data 1130 headers are currently being used, and may be used in the future. 1132 o Moved the packet capture example into an Appendix Implementation 1133 Status. 1135 o Suggested moving the reliability requirements appendix out into 1136 another document. 1138 o Added a IANA Consiserations section, with content, requesting for 1139 a new multicast group "all OCB interfaces". 1141 o Added new OBU term, improved the RSU term definition, removed the 1142 ETTC term, replaced more occurences of 802.11p, 802.11-OCB with 1143 802.11-OCB. 1145 o References: 1147 * Added an informational reference to ETSI's IPv6-over- 1148 GeoNetworking. 1150 * Added more references to IETF and ETSI security protocols. 1152 * Updated some references from I-D to RFC, and from old RFC to 1153 new RFC numbers. 1155 * Added reference to multicast extensions to IPsec architecture 1156 RFC. 1158 * Added a reference to 2464-bis. 1160 * Removed FCC informative references, because not used. 1162 o Updated the affiliation of one author. 1164 o Reformulation of some phrases for better readability, and 1165 correction of typographical errors. 1167 From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave- 1168 ipv6-over-80211ocb-04 1170 o Removed a few informative references pointing to Dx draft IEEE 1171 1609 documents. 1173 o Removed outdated informative references to ETSI documents. 1175 o Added citations to IEEE 1609.2, .3 and .4-2016. 1177 o Minor textual issues. 1179 From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave- 1180 ipv6-over-80211ocb-03 1182 o Keep the previous text on multiple addresses, so remove talk about 1183 MIP6, NEMOv6 and MCoA. 1185 o Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon. 1187 o Clarified the figure showing Infrastructure mode and OCB mode side 1188 by side. 1190 o Added a reference to the IP Security Architecture RFC. 1192 o Detailed the IPv6-per-channel prohibition paragraph which reflects 1193 the discussion at the last IETF IPWAVE WG meeting. 1195 o Added section "Address Mapping -- Unicast". 1197 o Added the ".11 Trailer" to pictures of 802.11 frames. 1199 o Added text about SNAP carrying the Ethertype. 1201 o New RSU definition allowing for it be both a Router and not 1202 necessarily a Router some times. 1204 o Minor textual issues. 1206 From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave- 1207 ipv6-over-80211ocb-02 1209 o Replaced almost all occurences of 802.11p with 802.11-OCB, leaving 1210 only when explanation of evolution was necessary. 1212 o Shortened by removing parameter details from a paragraph in the 1213 Introduction. 1215 o Moved a reference from Normative to Informative. 1217 o Added text in intro clarifying there is no handover spec at IEEE, 1218 and that 1609.2 does provide security services. 1220 o Named the contents the fields of the EthernetII header (including 1221 the Ethertype bitstring). 1223 o Improved relationship between two paragraphs describing the 1224 increase of the Sequence Number in 802.11 header upon IP 1225 fragmentation. 1227 o Added brief clarification of "tracking". 1229 From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave- 1230 ipv6-over-80211ocb-01 1232 o Introduced message exchange diagram illustrating differences 1233 between 802.11 and 802.11 in OCB mode. 1235 o Introduced an appendix listing for information the set of 802.11 1236 messages that may be transmitted in OCB mode. 1238 o Removed appendix sections "Privacy Requirements", "Authentication 1239 Requirements" and "Security Certificate Generation". 1241 o Removed appendix section "Non IP Communications". 1243 o Introductory phrase in the Security Considerations section. 1245 o Improved the definition of "OCB". 1247 o Introduced theoretical stacked layers about IPv6 and IEEE layers 1248 including EPD. 1250 o Removed the appendix describing the details of prohibiting IPv6 on 1251 certain channels relevant to 802.11-OCB. 1253 o Added a brief reference in the privacy text about a precise clause 1254 in IEEE 1609.3 and .4. 1256 o Clarified the definition of a Road Side Unit. 1258 o Removed the discussion about security of WSA (because is non-IP). 1260 o Removed mentioning of the GeoNetworking discussion. 1262 o Moved references to scientific articles to a separate 'overview' 1263 draft, and referred to it. 1265 Appendix B. 802.11p 1267 The term "802.11p" is an earlier definition. The behaviour of 1268 "802.11p" networks is rolled in the document IEEE Std 802.11-2016. 1269 In that document the term 802.11p disappears. Instead, each 802.11p 1270 feature is conditioned by the IEEE Management Information Base (MIB) 1271 attribute "OCBActivated" [IEEE-802.11-2016]. Whenever OCBActivated 1272 is set to true the IEEE Std 802.11-OCB state is activated. For 1273 example, an 802.11 STAtion operating outside the context of a basic 1274 service set has the OCBActivated flag set. Such a station, when it 1275 has the flag set, uses a BSS identifier equal to ff:ff:ff:ff:ff:ff. 1277 Appendix C. Aspects introduced by the OCB mode to 802.11 1279 In the IEEE 802.11-OCB mode, all nodes in the wireless range can 1280 directly communicate with each other without involving authentication 1281 or association procedures. In OCB mode, the manner in which channels 1282 are selected and used is simplified compared to when in BSS mode. 1284 Contrary to BSS mode, at link layer, it is necessary to set 1285 statically the same channel number (or frequency) on two stations 1286 that need to communicate with each other (in BSS mode this channel 1287 set operation is performed automatically during 'scanning'). The 1288 manner in which stations set their channel number in OCB mode is not 1289 specified in this document. Stations STA1 and STA2 can exchange IP 1290 packets only if they are set on the same channel. At IP layer, they 1291 then discover each other by using the IPv6 Neighbor Discovery 1292 protocol. The allocation of a particular channel for a particular 1293 use is defined statically in standards authored by ETSI (in Europe), 1294 FCC in America, and similar organisations in South Korea, Japan and 1295 other parts of the world. 1297 Briefly, the IEEE 802.11-OCB mode has the following properties: 1299 o The use by each node of a 'wildcard' BSSID (i.e., each bit of the 1300 BSSID is set to 1) 1302 o No IEEE 802.11 Beacon frames are transmitted 1304 o No authentication is required in order to be able to communicate 1306 o No association is needed in order to be able to communicate 1308 o No encryption is provided in order to be able to communicate 1310 o Flag dot11OCBActivated is set to true 1312 All the nodes in the radio communication range (IP-OBU and IP-RSU) 1313 receive all the messages transmitted (IP-OBU and IP-RSU) within the 1314 radio communications range. The eventual conflict(s) are resolved by 1315 the MAC CDMA function. 1317 The message exchange diagram in Figure 3 illustrates a comparison 1318 between traditional 802.11 and 802.11 in OCB mode. The 'Data' 1319 messages can be IP packets such as HTTP or others. Other 802.11 1320 management and control frames (non IP) may be transmitted, as 1321 specified in the 802.11 standard. For information, the names of 1322 these messages as currently specified by the 802.11 standard are 1323 listed in Appendix G. 1325 STA AP STA1 STA2 1326 | | | | 1327 |<------ Beacon -------| |<------ Data -------->| 1328 | | | | 1329 |---- Probe Req. ----->| |<------ Data -------->| 1330 |<--- Probe Res. ------| | | 1331 | | |<------ Data -------->| 1332 |---- Auth Req. ------>| | | 1333 |<--- Auth Res. -------| |<------ Data -------->| 1334 | | | | 1335 |---- Asso Req. ------>| |<------ Data -------->| 1336 |<--- Asso Res. -------| | | 1337 | | |<------ Data -------->| 1338 |<------ Data -------->| | | 1339 |<------ Data -------->| |<------ Data -------->| 1341 (i) 802.11 Infrastructure mode (ii) 802.11-OCB mode 1343 Figure 3: Difference between messages exchanged on 802.11 (left) and 1344 802.11-OCB (right) 1346 The interface 802.11-OCB was specified in IEEE Std 802.11p (TM) -2010 1347 [IEEE-802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, 1348 titled "Amendment 6: Wireless Access in Vehicular Environments". 1349 Since then, this amendment has been integrated in IEEE 802.11(TM) 1350 -2012 and -2016 [IEEE-802.11-2016]. 1352 In document 802.11-2016, anything qualified specifically as 1353 "OCBActivated", or "outside the context of a basic service" set to be 1354 true, then it is actually referring to OCB aspects introduced to 1355 802.11. 1357 In order to delineate the aspects introduced by 802.11-OCB to 802.11, 1358 we refer to the earlier [IEEE-802.11p-2010]. The amendment is 1359 concerned with vehicular communications, where the wireless link is 1360 similar to that of Wireless LAN (using a PHY layer specified by 1361 802.11a/b/g/n), but which needs to cope with the high mobility factor 1362 inherent in scenarios of communications between moving vehicles, and 1363 between vehicles and fixed infrastructure deployed along roads. 1364 While 'p' is a letter identifying the Ammendment, just like 'a, b, g' 1365 and 'n' are, 'p' is concerned more with MAC modifications, and a 1366 little with PHY modifications; the others are mainly about PHY 1367 modifications. It is possible in practice to combine a 'p' MAC with 1368 an 'a' PHY by operating outside the context of a BSS with OFDM at 1369 5.4GHz and 5.9GHz. 1371 The 802.11-OCB links are specified to be compatible as much as 1372 possible with the behaviour of 802.11a/b/g/n and future generation 1373 IEEE WLAN links. From the IP perspective, an 802.11-OCB MAC layer 1374 offers practically the same interface to IP as the 802.11a/b/g/n and 1375 802.3. A packet sent by an IP-OBU may be received by one or multiple 1376 IP-RSUs. The link-layer resolution is performed by using the IPv6 1377 Neighbor Discovery protocol. 1379 To support this similarity statement (IPv6 is layered on top of LLC 1380 on top of 802.11-OCB, in the same way that IPv6 is layered on top of 1381 LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on 1382 top of 802.3 (for Ethernet)) it is useful to analyze the differences 1383 between 802.11-OCB and 802.11 specifications. During this analysis, 1384 we note that whereas 802.11-OCB lists relatively complex and numerous 1385 changes to the MAC layer (and very little to the PHY layer), there 1386 are only a few characteristics which may be important for an 1387 implementation transmitting IPv6 packets on 802.11-OCB links. 1389 The most important 802.11-OCB point which influences the IPv6 1390 functioning is the OCB characteristic; an additional, less direct 1391 influence, is the maximum bandwidth afforded by the PHY modulation/ 1392 demodulation methods and channel access specified by 802.11-OCB. The 1393 maximum bandwidth theoretically possible in 802.11-OCB is 54 Mbit/s 1394 (when using, for example, the following parameters: 20 MHz channel; 1395 modulation 64-QAM; coding rate R is 3/4); in practice of IP-over- 1396 802.11-OCB a commonly observed figure is 12Mbit/s; this bandwidth 1397 allows the operation of a wide range of protocols relying on IPv6. 1399 o Operation Outside the Context of a BSS (OCB): the (earlier 1400 802.11p) 802.11-OCB links are operated without a Basic Service Set 1401 (BSS). This means that the frames IEEE 802.11 Beacon, Association 1402 Request/Response, Authentication Request/Response, and similar, 1403 are not used. The used identifier of BSS (BSSID) has a 1404 hexadecimal value always 0xffffffffffff (48 '1' bits, represented 1405 as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' 1406 BSSID), as opposed to an arbitrary BSSID value set by 1407 administrator (e.g. 'My-Home-AccessPoint'). The OCB operation - 1408 namely the lack of beacon-based scanning and lack of 1409 authentication - should be taken into account when the Mobile IPv6 1410 protocol [RFC6275] and the protocols for IP layer security 1411 [RFC4301] are used. The way these protocols adapt to OCB is not 1412 described in this document. 1414 o Timing Advertisement: is a new message defined in 802.11-OCB, 1415 which does not exist in 802.11a/b/g/n. This message is used by 1416 stations to inform other stations about the value of time. It is 1417 similar to the time as delivered by a GNSS system (Galileo, GPS, 1418 ...) or by a cellular system. This message is optional for 1419 implementation. 1421 o Frequency range: this is a characteristic of the PHY layer, with 1422 almost no impact on the interface between MAC and IP. However, it 1423 is worth considering that the frequency range is regulated by a 1424 regional authority (ARCEP, ECC/CEPT based on ENs from ETSI, FCC, 1425 etc.); as part of the regulation process, specific applications 1426 are associated with specific frequency ranges. In the case of 1427 802.11-OCB, the regulator associates a set of frequency ranges, or 1428 slots within a band, to the use of applications of vehicular 1429 communications, in a band known as "5.9GHz". The 5.9GHz band is 1430 different from the 2.4GHz and 5GHz bands used by Wireless LAN. 1431 However, as with Wireless LAN, the operation of 802.11-OCB in 1432 "5.9GHz" bands is exempt from owning a license in EU (in US the 1433 5.9GHz is a licensed band of spectrum; for the fixed 1434 infrastructure an explicit FCC authorization is required; for an 1435 on-board device a 'licensed-by-rule' concept applies: rule 1436 certification conformity is required.) Technical conditions are 1437 different than those of the bands "2.4GHz" or "5GHz". The allowed 1438 power levels, and implicitly the maximum allowed distance between 1439 vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20 1440 dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum 1441 distance of approximately 1km, compared to approximately 50m. 1442 Additionally, specific conditions related to congestion avoidance, 1443 jamming avoidance, and radar detection are imposed on the use of 1444 DSRC (in US) and on the use of frequencies for Intelligent 1445 Transportation Systems (in EU), compared to Wireless LAN 1446 (802.11a/b/g/n). 1448 o 'Half-rate' encoding: as the frequency range, this parameter is 1449 related to PHY, and thus has not much impact on the interface 1450 between the IP layer and the MAC layer. 1452 o In vehicular communications using 802.11-OCB links, there are 1453 strong privacy requirements with respect to addressing. While the 1454 802.11-OCB standard does not specify anything in particular with 1455 respect to MAC addresses, in these settings there exists a strong 1456 need for dynamic change of these addresses (as opposed to the non- 1457 vehicular settings - real wall protection - where fixed MAC 1458 addresses do not currently pose some privacy risks). This is 1459 further described in Section 5. A relevant function is described 1460 in documents IEEE 1609.3-2016 [IEEE-1609.3] and IEEE 1609.4-2016 1461 [IEEE-1609.4]. 1463 Appendix D. Changes Needed on a software driver 802.11a to become a 1464 802.11-OCB driver 1466 The 802.11p amendment modifies both the 802.11 stack's physical and 1467 MAC layers but all the induced modifications can be quite easily 1468 obtained by modifying an existing 802.11a ad-hoc stack. 1470 Conditions for a 802.11a hardware to be 802.11-OCB compliant: 1472 o The PHY entity shall be an orthogonal frequency division 1473 multiplexing (OFDM) system. It must support the frequency bands 1474 on which the regulator recommends the use of ITS communications, 1475 for example using IEEE 802.11-OCB layer, in France: 5875MHz to 1476 5925MHz. 1478 o The OFDM system must provide a "half-clocked" operation using 10 1479 MHz channel spacings. 1481 o The chip transmit spectrum mask must be compliant to the "Transmit 1482 spectrum mask" from the IEEE 802.11p amendment (but experimental 1483 environments tolerate otherwise). 1485 o The chip should be able to transmit up to 44.8 dBm when used by 1486 the US government in the United States, and up to 33 dBm in 1487 Europe; other regional conditions apply. 1489 Changes needed on the network stack in OCB mode: 1491 o Physical layer: 1493 * The chip must use the Orthogonal Frequency Multiple Access 1494 (OFDM) encoding mode. 1496 * The chip must be set in half-mode rate mode (the internal clock 1497 frequency is divided by two). 1499 * The chip must use dedicated channels and should allow the use 1500 of higher emission powers. This may require modifications to 1501 the local computer file that describes regulatory domains 1502 rules, if used by the kernel to enforce local specific 1503 restrictions. Such modifications to the local computer file 1504 must respect the location-specific regulatory rules. 1506 MAC layer: 1508 * All management frames (beacons, join, leave, and others) 1509 emission and reception must be disabled except for frames of 1510 subtype Action and Timing Advertisement (defined below). 1512 * No encryption key or method must be used. 1514 * Packet emission and reception must be performed as in ad-hoc 1515 mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff). 1517 * The functions related to joining a BSS (Association Request/ 1518 Response) and for authentication (Authentication Request/Reply, 1519 Challenge) are not called. 1521 * The beacon interval is always set to 0 (zero). 1523 * Timing Advertisement frames, defined in the amendment, should 1524 be supported. The upper layer should be able to trigger such 1525 frames emission and to retrieve information contained in 1526 received Timing Advertisements. 1528 Appendix E. Protocol Layering 1530 A more theoretical and detailed view of layer stacking, and 1531 interfaces between the IP layer and 802.11-OCB layers, is illustrated 1532 in Figure 4. The IP layer operates on top of the EtherType Protocol 1533 Discrimination (EPD); this Discrimination layer is described in IEEE 1534 Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP 1535 (Link Layer Control Service Access Point). 1537 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1538 | IPv6 | 1539 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ 1540 { LLC_SAP } 802.11-OCB 1541 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary 1542 | EPD | | | 1543 | | MLME | | 1544 +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | 1545 | MAC Sublayer | | | 802.11-OCB 1546 | and ch. coord. | | SME | Services 1547 +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | 1548 | | PLME | | 1549 | PHY Layer | PLME_SAP | 1550 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1552 Figure 4: EtherType Protocol Discrimination 1554 Appendix F. Design Considerations 1556 The networks defined by 802.11-OCB are in many ways similar to other 1557 networks of the 802.11 family. In theory, the encapsulation of IPv6 1558 over 802.11-OCB could be very similar to the operation of IPv6 over 1559 other networks of the 802.11 family. However, the high mobility, 1560 strong link asymmetry and very short connection makes the 802.11-OCB 1561 link significantly different from other 802.11 networks. Also, the 1562 automotive applications have specific requirements for reliability, 1563 security and privacy, which further add to the particularity of the 1564 802.11-OCB link. 1566 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode 1568 For information, at the time of writing, this is the list of IEEE 1569 802.11 messages that may be transmitted in OCB mode, i.e. when 1570 dot11OCBActivated is true in a STA: 1572 o The STA may send management frames of subtype Action and, if the 1573 STA maintains a TSF Timer, subtype Timing Advertisement; 1575 o The STA may send control frames, except those of subtype PS-Poll, 1576 CF-End, and CF-End plus CFAck; 1578 o The STA may send data frames of subtype Data, Null, QoS Data, and 1579 QoS Null. 1581 Appendix H. Examples of Packet Formats 1583 This section describes an example of an IPv6 Packet captured over a 1584 IEEE 802.11-OCB link. 1586 By way of example we show that there is no modification in the 1587 headers when transmitted over 802.11-OCB networks - they are 1588 transmitted like any other 802.11 and Ethernet packets. 1590 We describe an experiment of capturing an IPv6 packet on an 1591 802.11-OCB link. In topology depicted in Figure 5, the packet is an 1592 IPv6 Router Advertisement. This packet is emitted by a Router on its 1593 802.11-OCB interface. The packet is captured on the Host, using a 1594 network protocol analyzer (e.g. Wireshark); the capture is performed 1595 in two different modes: direct mode and 'monitor' mode. The topology 1596 used during the capture is depicted below. 1598 The packet is captured on the Host. The Host is an IP-OBU containing 1599 an 802.11 interface in format PCI express (an ITRI product). The 1600 kernel runs the ath5k software driver with modifications for OCB 1601 mode. The capture tool is Wireshark. The file format for save and 1602 analyze is 'pcap'. The packet is generated by the Router. The 1603 Router is an IP-RSU (ITRI product). 1605 +--------+ +-------+ 1606 | | 802.11-OCB Link | | 1607 ---| Router |--------------------------------| Host | 1608 | | | | 1609 +--------+ +-------+ 1611 Figure 5: Topology for capturing IP packets on 802.11-OCB 1613 During several capture operations running from a few moments to 1614 several hours, no message relevant to the BSSID contexts were 1615 captured (no Association Request/Response, Authentication Req/Resp, 1616 Beacon). This shows that the operation of 802.11-OCB is outside the 1617 context of a BSSID. 1619 Overall, the captured message is identical with a capture of an IPv6 1620 packet emitted on a 802.11b interface. The contents are precisely 1621 similar. 1623 H.1. Capture in Monitor Mode 1625 The IPv6 RA packet captured in monitor mode is illustrated below. 1626 The radio tap header provides more flexibility for reporting the 1627 characteristics of frames. The Radiotap Header is prepended by this 1628 particular stack and operating system on the Host machine to the RA 1629 packet received from the network (the Radiotap Header is not present 1630 on the air). The implementation-dependent Radiotap Header is useful 1631 for piggybacking PHY information from the chip's registers as data in 1632 a packet understandable by userland applications using Socket 1633 interfaces (the PHY interface can be, for example: power levels, data 1634 rate, ratio of signal to noise). 1636 The packet present on the air is formed by IEEE 802.11 Data Header, 1637 Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. 1639 Radiotap Header v0 1640 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1641 |Header Revision| Header Pad | Header length | 1642 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1643 | Present flags | 1644 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1645 | Data Rate | Pad | 1646 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1648 IEEE 802.11 Data Header 1649 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1650 | Type/Subtype and Frame Ctrl | Duration | 1651 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1652 | Receiver Address... 1653 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1654 ... Receiver Address | Transmitter Address... 1655 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1656 ... Transmitter Address | 1657 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1658 | BSS Id... 1659 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1660 ... BSS Id | Frag Number and Seq Number | 1661 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1663 Logical-Link Control Header 1664 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1665 | DSAP |I| SSAP |C| Control field | Org. code... 1666 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1667 ... Organizational Code | Type | 1668 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1670 IPv6 Base Header 1671 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1672 |Version| Traffic Class | Flow Label | 1673 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1674 | Payload Length | Next Header | Hop Limit | 1675 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1676 | | 1677 + + 1678 | | 1679 + Source Address + 1680 | | 1681 + + 1682 | | 1683 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1684 | | 1685 + + 1686 | | 1687 + Destination Address + 1688 | | 1689 + + 1690 | | 1691 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1693 Router Advertisement 1694 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1695 | Type | Code | Checksum | 1696 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1697 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1698 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1699 | Reachable Time | 1700 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1701 | Retrans Timer | 1702 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1703 | Options ... 1704 +-+-+-+-+-+-+-+-+-+-+-+- 1706 The value of the Data Rate field in the Radiotap header is set to 6 1707 Mb/s. This indicates the rate at which this RA was received. 1709 The value of the Transmitter address in the IEEE 802.11 Data Header 1710 is set to a 48bit value. The value of the destination address is 1711 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS 1712 Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network 1713 protocol analyzer as being "broadcast". The Fragment number and 1714 sequence number fields are together set to 0x90C6. 1716 The value of the Organization Code field in the Logical-Link Control 1717 Header is set to 0x0, recognized as "Encapsulated Ethernet". The 1718 value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise 1719 #86DD), recognized as "IPv6". 1721 A Router Advertisement is periodically sent by the router to 1722 multicast group address ff02::1. It is an icmp packet type 134. The 1723 IPv6 Neighbor Discovery's Router Advertisement message contains an 1724 8-bit field reserved for single-bit flags, as described in [RFC4861]. 1726 The IPv6 header contains the link local address of the router 1727 (source) configured via EUI-64 algorithm, and destination address set 1728 to ff02::1. 1730 The Ethernet Type field in the logical-link control header is set to 1731 0x86dd which indicates that the frame transports an IPv6 packet. In 1732 the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 1733 which is the corresponding multicast MAC address. The BSS id is a 1734 broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link 1735 duration between vehicles and the roadside infrastructure, there is 1736 no need in IEEE 802.11-OCB to wait for the completion of association 1737 and authentication procedures before exchanging data. IEEE 1738 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) 1739 and may start communicating as soon as they arrive on the 1740 communication channel. 1742 H.2. Capture in Normal Mode 1744 The same IPv6 Router Advertisement packet described above (monitor 1745 mode) is captured on the Host, in the Normal mode, and depicted 1746 below. 1748 Ethernet II Header 1749 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1750 | Destination... 1751 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1752 ...Destination | Source... 1753 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1754 ...Source | 1755 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1756 | Type | 1757 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1759 IPv6 Base Header 1760 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1761 |Version| Traffic Class | Flow Label | 1762 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1763 | Payload Length | Next Header | Hop Limit | 1764 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1765 | | 1766 + + 1767 | | 1768 + Source Address + 1769 | | 1770 + + 1771 | | 1772 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1773 | | 1774 + + 1775 | | 1776 + Destination Address + 1777 | | 1778 + + 1779 | | 1780 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1782 Router Advertisement 1783 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1784 | Type | Code | Checksum | 1785 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1786 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1787 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1788 | Reachable Time | 1789 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1790 | Retrans Timer | 1791 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1792 | Options ... 1793 +-+-+-+-+-+-+-+-+-+-+-+- 1795 One notices that the Radiotap Header, the IEEE 802.11 Data Header and 1796 the Logical-Link Control Headers are not present. On the other hand, 1797 a new header named Ethernet II Header is present. 1799 The Destination and Source addresses in the Ethernet II header 1800 contain the same values as the fields Receiver Address and 1801 Transmitter Address present in the IEEE 802.11 Data Header in the 1802 "monitor" mode capture. 1804 The value of the Type field in the Ethernet II header is 0x86DD 1805 (recognized as "IPv6"); this value is the same value as the value of 1806 the field Type in the Logical-Link Control Header in the "monitor" 1807 mode capture. 1809 The knowledgeable experimenter will no doubt notice the similarity of 1810 this Ethernet II Header with a capture in normal mode on a pure 1811 Ethernet cable interface. 1813 An Adaptation layer is inserted on top of a pure IEEE 802.11 MAC 1814 layer, in order to adapt packets, before delivering the payload data 1815 to the applications. It adapts 802.11 LLC/MAC headers to Ethernet II 1816 headers. In further detail, this adaptation consists in the 1817 elimination of the Radiotap, 802.11 and LLC headers, and in the 1818 insertion of the Ethernet II header. In this way, IPv6 runs straight 1819 over LLC over the 802.11-OCB MAC layer; this is further confirmed by 1820 the use of the unique Type 0x86DD. 1822 Appendix I. Extra Terminology 1824 The following terms are defined outside the IETF. They are used to 1825 define the main terms in the main terminology section Section 2. 1827 DSRC (Dedicated Short Range Communication): a term defined outside 1828 the IETF. The US Federal Communications Commission (FCC) Dedicated 1829 Short Range Communication (DSRC) is defined in the Code of Federal 1830 Regulations (CFR) 47, Parts 90 and 95. This Code is referred in the 1831 definitions below. At the time of the writing of this Internet 1832 Draft, the last update of this Code was dated October 1st, 2010. 1834 DSRCS (Dedicated Short-Range Communications Services): a term defined 1835 outside the IETF. The use of radio techniques to transfer data over 1836 short distances between roadside and mobile units, between mobile 1837 units, and between portable and mobile units to perform operations 1838 related to the improvement of traffic flow, traffic safety, and other 1839 intelligent transportation service applications in a variety of 1840 environments. DSRCS systems may also transmit status and 1841 instructional messages related to the units involve. [Ref. 47 CFR 1842 90.7 - Definitions] 1843 OBU (On-Board Unit): a term defined outside the IETF. An On-Board 1844 Unit is a DSRCS transceiver that is normally mounted in or on a 1845 vehicle, or which in some instances may be a portable unit. An OBU 1846 can be operational while a vehicle or person is either mobile or 1847 stationary. The OBUs receive and contend for time to transmit on one 1848 or more radio frequency (RF) channels. Except where specifically 1849 excluded, OBU operation is permitted wherever vehicle operation or 1850 human passage is permitted. The OBUs mounted in vehicles are 1851 licensed by rule under part 95 of the respective chapter and 1852 communicate with Roadside Units (RSUs) and other OBUs. Portable OBUs 1853 are also licensed by rule under part 95 of the respective chapter. 1854 OBU operations in the Unlicensed National Information Infrastructure 1855 (UNII) Bands follow the rules in those bands. - [CFR 90.7 - 1856 Definitions]. 1858 RSU (Road-Side Unit): a term defined outside of IETF. A Roadside 1859 Unit is a DSRC transceiver that is mounted along a road or pedestrian 1860 passageway. An RSU may also be mounted on a vehicle or is hand 1861 carried, but it may only operate when the vehicle or hand- carried 1862 unit is stationary. Furthermore, an RSU operating under the 1863 respectgive part is restricted to the location where it is licensed 1864 to operate. However, portable or hand-held RSUs are permitted to 1865 operate where they do not interfere with a site-licensed operation. 1866 A RSU broadcasts data to OBUs or exchanges data with OBUs in its 1867 communications zone. An RSU also provides channel assignments and 1868 operating instructions to OBUs in its communications zone, when 1869 required. - [CFR 90.7 - Definitions]. 1871 Appendix J. Neighbor Discovery (ND) Potential Issues in Wireless Links 1873 IPv6 Neighbor Discovery (IPv6 ND) [RFC4861][RFC4862] was designed for 1874 point-to-point and transit links such as Ethernet, with the 1875 expectation of a cheap and reliable support for multicast from the 1876 lower layer. Section 3.2 of RFC 4861 indicates that the operation on 1877 Shared Media and on non-broadcast multi-access (NBMA) networks 1878 require additional support, e.g., for Address Resolution (AR) and 1879 duplicate address detection (DAD), which depend on multicast. An 1880 infrastructureless radio network such as OCB shares properties with 1881 both Shared Media and NBMA networks, and then adds its own 1882 complexity, e.g., from movement and interference that allow only 1883 transient and non-transitive reachability between any set of peers. 1885 The uniqueness of an address within a scoped domain is a key pillar 1886 of IPv6 and the base for unicast IP communication. RFC 4861 details 1887 the DAD method to avoid that an address is duplicated. For a link 1888 local address, the scope is the link, whereas for a global address 1889 the scope is much larger. The underlying assumption for DAD to 1890 operate correctly is that the node that owns an IPv6 address can 1891 reach any other node within the scope at the time it claims its 1892 address, which is done by sending a NS multicast message, and can 1893 hear any future claim for that address by another party within the 1894 scope for the duration of the address ownership. 1896 In the case of OCB, there is a potentially a need to define a scope 1897 that is compatible with DAD, and that cannot be the set of nodes that 1898 a transmitter can reach at a particular time, because that set varies 1899 all the time and does not meet the DAD requirements for a link local 1900 address that could possibly be used anytime, anywhere. The generic 1901 expectation of a reliable multicast is not ensured, and the operation 1902 of DAD and AR (Address Resolution) as specificed by RFC 4861 cannot 1903 be guaranteed. Moreoever, multicast transmissions that rely on 1904 broadcast are not only unreliable but are also often detrimental to 1905 unicast traffic (see [draft-ietf-mboned-ieee802-mcast-problems]). 1907 Early experiences indicate that it should be possible to exchange 1908 IPv6 packets over OCB while relying on IPv6 ND alone for DAD and AR 1909 (Address Resolution). In the absence of a correct DAD operation, a 1910 node that relies only on IPv6 ND for AR and DAD over OCB should 1911 ensure that the addresses that it uses are unique by means others 1912 than DAD. It must be noted that deriving an IPv6 address from a 1913 globally unique MAC address has this property but may yield privacy 1914 issues. 1916 RFC 8505 provides a more recent approach to IPv6 ND and in particular 1917 DAD. RFC 8505 is designed to fit wireless and otherwise constrained 1918 networks whereby multicast and/or continuous access to the medium may 1919 not be guaranteed. RFC 8505 Section 5.6 "Link-Local Addresses and 1920 Registration" indicates that the scope of uniqueness for a link local 1921 address is restricted to a pair of nodes that use it to communicate, 1922 and provides a method to assert the uniqueness and resolve the link- 1923 Layer address using a unicast exchange. 1925 RFC 8505 also enables a router (acting as a 6LR) to own a prefix and 1926 act as a registrar (acting as a 6LBR) for addresses within the 1927 associated subnet. A peer host (acting as a 6LN) registers an 1928 address derived from that prefix and can use it for the lifetime of 1929 the registration. The prefix is advertised as not onlink, which 1930 means that the 6LN uses the 6LR to relay its packets within the 1931 subnet, and participation to the subnet is constrained to the time of 1932 reachability to the 6LR. Note that RSU that provides internet 1933 connectivity MAY announce a default router preference [RFC 4191], 1934 whereas a car that does not provide that connectivity MUST NOT do so. 1935 This operation presents similarities with that of an access point, 1936 but at Layer-3. This is why RFC 8505 well-suited for wireless in 1937 general. 1939 Support of RFC 8505 is may be implemented on OCB. OCB nodes that 1940 support RFC 8505 would support the 6LN operation in order to act as a 1941 host, and may support the 6LR and 6LBR operations in order to act as 1942 a router and in particular own a prefix that can be used by RFC 1943 8505-compliant hosts for address autoconfiguration and registration. 1945 Authors' Addresses 1947 Alexandre Petrescu 1948 CEA, LIST 1949 CEA Saclay 1950 Gif-sur-Yvette , Ile-de-France 91190 1951 France 1953 Phone: +33169089223 1954 Email: Alexandre.Petrescu@cea.fr 1956 Nabil Benamar 1957 Moulay Ismail University 1958 Morocco 1960 Phone: +212670832236 1961 Email: n.benamar@est.umi.ac.ma 1963 Jerome Haerri 1964 Eurecom 1965 Sophia-Antipolis 06904 1966 France 1968 Phone: +33493008134 1969 Email: Jerome.Haerri@eurecom.fr 1971 Jong-Hyouk Lee 1972 Sangmyung University 1973 31, Sangmyeongdae-gil, Dongnam-gu 1974 Cheonan 31066 1975 Republic of Korea 1977 Email: jonghyouk@smu.ac.kr 1978 Thierry Ernst 1979 YoGoKo 1980 France 1982 Email: thierry.ernst@yogoko.fr