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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 9, 2019) is 1836 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 1871, but not defined == Missing Reference: 'RFC 4191' is mentioned on line 1931, 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reference: RFC 7042 (Obsoleted by RFC 9542) ** Downref: Normative reference to an Informational RFC: RFC 7721 == Outdated reference: A later version (-15) exists of draft-ietf-mboned-ieee802-mcast-problems-04 Summary: 5 errors (**), 0 flaws (~~), 5 warnings (==), 2 comments (--).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 11, 2019 Moulay Ismail University 6 J. Haerri 7 Eurecom 8 J. Lee 9 Sangmyung University 10 T. Ernst 11 YoGoKo 12 April 9, 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-37 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 11, 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 fe80::/10 and the 365 interfaces MUST be assigned IPv6 addresses 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 and William Whyte. Their valuable 561 comments clarified particular issues and generally helped to improve 562 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 -37: added a section about issues on ND wireless; added the qualifier 784 'baseline' to using ND on 802.11-OCB; improved the description of the 785 reference to 802.11-2016 document, with a qualifier about the 786 difficulty of accessing it, even though it is free. 788 -36: removed a phrase about the IID formation and MAC generation, but 789 left in the section 5.2 that describes how it happens. 791 -35: addressing the the intarea review: clarified a small apparent 792 contradiction between two parts of text that use the old MAC-based 793 IIDs (clarified by using qualifiers from each other: transition time, 794 and ll addresses); sequenced closer the LL and Stateless Autoconf 795 sections, instead of spacing them; shortened the paragraph of Opaque 796 IIDs; moved the privacy risks of in-clear IIDs in the security 797 section; removed a short phrase duplicating the idea of privacy 798 risks; added third time a reference to the 802.11-2016 document; used 799 'the hidden terminal' text; updated the Terminology section with new 800 BCP-14 text 'MUST' to include RFC8174. 802 -33: substituted 'movement detection' for 'handover behaviour' in 803 introductory text; removed redundant phrase referring to Security 804 Considerations section; removed the phrase about forming mechanisms 805 being left out, as IP is not much concerned about L2 forming; moved 806 the Pseudonym section from main section to end of Security 807 Considerations section (and clarified 'concurrently'); capitalized 808 SHOULD consider OCB in WiFi multicast problems, and referred to more 809 recent I-D on topic; removed several phrases in a paragraph about 810 oui.txt and MAC presence in IPv6 address, as they are well known 811 info, but clarified the example of privacy risk of Company ID in MAC 812 addresses in public roads; clarified that ND MUST be used over 813 802.11-OCB. 815 -32: significantly shortened the relevant ND/OCB paragraph. It now 816 just states ND is used over OCB, w/o detailing. 818 -31: filled in the section titled "Pseudonym Handling"; removed a 819 'MAY NOT' phrase about possibility of having other prefix than the LL 820 on the link between cars; shortened and improved the paragraph about 821 Mobile IPv6, now with DNAv6; improved the ND text about ND 822 retransmissions with relationship to packet loss; changed the title 823 of an appendix from 'EPD' to 'Protocol Layering'; improved the 824 'Aspects introduced by OCB' appendix with a few phrases about the 825 channel use and references. 827 -30: a clarification on the reliability of ND over OCB and over 828 802.11. 830 -29: 832 o 834 -28: 836 o Created a new section 'Pseudonym Handling'. 838 o removed the 'Vehicle ID' appendix. 840 o improved the address generation from random MAC address. 842 o shortened Term IP-RSU definition. 844 o removed refs to two detail Clauses in IEEE documents, kept just 845 these latter. 847 -27: part 1 of addressing Human Rights review from IRTF. Removed 848 appendices F.2 and F.3. Shortened definition of IP-RSU. Removed 849 reference to 1609.4. A few other small changes, see diff. 851 -26: moved text from SLAAC section and from Design Considerations 852 appendix about privacy into a new Privacy Condiderations subsection 853 of the Security section; reformulated the SLAAC and IID sections to 854 stress only LLs can use EUI-64; removed the "GeoIP" wireshark 855 explanation; reformulated SLAAC and LL sections; added brief mention 856 of need of use LLs; clarified text about MAC address changes; dropped 857 pseudonym discussion; changed title of section describing examples of 858 packet formats. 860 -25: added a reference to 'IEEE Management Information Base', instead 861 of just 'Management Information Base'; added ref to further 862 appendices in the introductory phrases; improved text for IID 863 formation for SLAAC, inserting recommendation for RFC8064 before 864 RFC2464. 866 From draft-ietf-ipwave-ipv6-over-80211ocb-23 to draft-ietf-ipwave- 867 ipv6-over-80211ocb-24 869 o Nit: wrote "IPWAVE Working Group" on the front page, instead of 870 "Network Working Group". 872 o Addressed the comments on 6MAN: replaced a sentence about ND 873 problem with "is used over 802.11-OCB". 875 From draft-ietf-ipwave-ipv6-over-80211ocb-22 to draft-ietf-ipwave- 876 ipv6-over-80211ocb-23 878 o No content modifications, but check the entire draft chain on 879 IPv6-only: xml2rfc, submission on tools.ietf.org and datatracker. 881 From draft-ietf-ipwave-ipv6-over-80211ocb-21 to draft-ietf-ipwave- 882 ipv6-over-80211ocb-22 884 o Corrected typo, use dash in "802.11-OCB" instead of space. 886 o Improved the Frame Format section: MUST use QoSData, specify the 887 values within; clarified the Ethernet Adaptation Layer text. 889 From draft-ietf-ipwave-ipv6-over-80211ocb-20 to draft-ietf-ipwave- 890 ipv6-over-80211ocb-21 892 o Corrected a few nits and added names in Acknowledgments section. 894 o Removed unused reference to old Internet Draft tsvwg about QoS. 896 From draft-ietf-ipwave-ipv6-over-80211ocb-19 to draft-ietf-ipwave- 897 ipv6-over-80211ocb-20 899 o Reduced the definition of term "802.11-OCB". 901 o Left out of this specification which 802.11 header to use to 902 transmit IP packets in OCB mode (QoS Data header, Data header, or 903 any other). 905 o Added 'MUST' use an Ethernet Adaptation Layer, instead of 'is 906 using' an Ethernet Adaptation Layer. 908 From draft-ietf-ipwave-ipv6-over-80211ocb-18 to draft-ietf-ipwave- 909 ipv6-over-80211ocb-19 911 o Removed the text about fragmentation. 913 o Removed the mentioning of WSMP and GeoNetworking. 915 o Removed the explanation of the binary representation of the 916 EtherType. 918 o Rendered normative the paragraph about unicast and multicast 919 address mapping. 921 o Removed paragraph about addressing model, subnet structure and 922 easiness of using LLs. 924 o Clarified the Type/Subtype field in the 802.11 Header. 926 o Used RECOMMENDED instead of recommended, for the stable interface 927 identifiers. 929 From draft-ietf-ipwave-ipv6-over-80211ocb-17 to draft-ietf-ipwave- 930 ipv6-over-80211ocb-18 932 o Improved the MTU and fragmentation paragraph. 934 From draft-ietf-ipwave-ipv6-over-80211ocb-16 to draft-ietf-ipwave- 935 ipv6-over-80211ocb-17 937 o Susbtituted "MUST be increased" to "is increased" in the MTU 938 section, about fragmentation. 940 From draft-ietf-ipwave-ipv6-over-80211ocb-15 to draft-ietf-ipwave- 941 ipv6-over-80211ocb-16 942 o Removed the definition of the 'WiFi' term and its occurences. 943 Clarified a phrase that used it in Appendix C "Aspects introduced 944 by the OCB mode to 802.11". 946 o Added more normative words: MUST be 0x86DD, MUST fragment if size 947 larger than MTU, Sequence number in 802.11 Data header MUST be 948 increased. 950 From draft-ietf-ipwave-ipv6-over-80211ocb-14 to draft-ietf-ipwave- 951 ipv6-over-80211ocb-15 953 o Added normative term MUST in two places in section "Ethernet 954 Adaptation Layer". 956 From draft-ietf-ipwave-ipv6-over-80211ocb-13 to draft-ietf-ipwave- 957 ipv6-over-80211ocb-14 959 o Created a new Appendix titled "Extra Terminology" that contains 960 terms DSRC, DSRCS, OBU, RSU as defined outside IETF. Some of them 961 are used in the main Terminology section. 963 o Added two paragraphs explaining that ND and Mobile IPv6 have 964 problems working over 802.11-OCB, yet their adaptations is not 965 specified in this document. 967 From draft-ietf-ipwave-ipv6-over-80211ocb-12 to draft-ietf-ipwave- 968 ipv6-over-80211ocb-13 970 o Substituted "IP-OBU" for "OBRU", and "IP-RSU" for "RSRU" 971 throughout and improved OBU-related definitions in the Terminology 972 section. 974 From draft-ietf-ipwave-ipv6-over-80211ocb-11 to draft-ietf-ipwave- 975 ipv6-over-80211ocb-12 977 o Improved the appendix about "MAC Address Generation" by expressing 978 the technique to be an optional suggestion, not a mandatory 979 mechanism. 981 From draft-ietf-ipwave-ipv6-over-80211ocb-10 to draft-ietf-ipwave- 982 ipv6-over-80211ocb-11 984 o Shortened the paragraph on forming/terminating 802.11-OCB links. 986 o Moved the draft tsvwg-ieee-802-11 to Informative References. 988 From draft-ietf-ipwave-ipv6-over-80211ocb-09 to draft-ietf-ipwave- 989 ipv6-over-80211ocb-10 990 o Removed text requesting a new Group ID for multicast for OCB. 992 o Added a clarification of the meaning of value "3333" in the 993 section Address Mapping -- Multicast. 995 o Added note clarifying that in Europe the regional authority is not 996 ETSI, but "ECC/CEPT based on ENs from ETSI". 998 o Added note stating that the manner in which two STAtions set their 999 communication channel is not described in this document. 1001 o Added a time qualifier to state that the "each node is represented 1002 uniquely at a certain point in time." 1004 o Removed text "This section may need to be moved" (the "Reliability 1005 Requirements" section). This section stays there at this time. 1007 o In the term definition "802.11-OCB" added a note stating that "any 1008 implementation should comply with standards and regulations set in 1009 the different countries for using that frequency band." 1011 o In the RSU term definition, added a sentence explaining the 1012 difference between RSU and RSRU: in terms of number of interfaces 1013 and IP forwarding. 1015 o Replaced "with at least two IP interfaces" with "with at least two 1016 real or virtual IP interfaces". 1018 o Added a term in the Terminology for "OBU". However the definition 1019 is left empty, as this term is defined outside IETF. 1021 o Added a clarification that it is an OBU or an OBRU in this phrase 1022 "A vehicle embarking an OBU or an OBRU". 1024 o Checked the entire document for a consistent use of terms OBU and 1025 OBRU. 1027 o Added note saying that "'p' is a letter identifying the 1028 Ammendment". 1030 o Substituted lower case for capitals SHALL or MUST in the 1031 Appendices. 1033 o Added reference to RFC7042, helpful in the 3333 explanation. 1034 Removed reference to individual submission draft-petrescu-its- 1035 scenario-reqs and added reference to draft-ietf-ipwave-vehicular- 1036 networking-survey. 1038 o Added figure captions, figure numbers, and references to figure 1039 numbers instead of 'below'. Replaced "section Section" with 1040 "section" throughout. 1042 o Minor typographical errors. 1044 From draft-ietf-ipwave-ipv6-over-80211ocb-08 to draft-ietf-ipwave- 1045 ipv6-over-80211ocb-09 1047 o Significantly shortened the Address Mapping sections, by text 1048 copied from RFC2464, and rather referring to it. 1050 o Moved the EPD description to an Appendix on its own. 1052 o Shortened the Introduction and the Abstract. 1054 o Moved the tutorial section of OCB mode introduced to .11, into an 1055 appendix. 1057 o Removed the statement that suggests that for routing purposes a 1058 prefix exchange mechanism could be needed. 1060 o Removed refs to RFC3963, RFC4429 and RFC6775; these are about ND, 1061 MIP/NEMO and oDAD; they were referred in the handover discussion 1062 section, which is out. 1064 o Updated a reference from individual submission to now a WG item in 1065 IPWAVE: the survey document. 1067 o Added term definition for WiFi. 1069 o Updated the authorship and expanded the Contributors section. 1071 o Corrected typographical errors. 1073 From draft-ietf-ipwave-ipv6-over-80211ocb-07 to draft-ietf-ipwave- 1074 ipv6-over-80211ocb-08 1076 o Removed the per-channel IPv6 prohibition text. 1078 o Corrected typographical errors. 1080 From draft-ietf-ipwave-ipv6-over-80211ocb-06 to draft-ietf-ipwave- 1081 ipv6-over-80211ocb-07 1083 o Added new terms: OBRU and RSRU ('R' for Router). Refined the 1084 existing terms RSU and OBU, which are no longer used throughout 1085 the document. 1087 o Improved definition of term "802.11-OCB". 1089 o Clarified that OCB does not "strip" security, but that the 1090 operation in OCB mode is "stripped off of all .11 security". 1092 o Clarified that theoretical OCB bandwidth speed is 54mbits, but 1093 that a commonly observed bandwidth in IP-over-OCB is 12mbit/s. 1095 o Corrected typographical errors, and improved some phrasing. 1097 From draft-ietf-ipwave-ipv6-over-80211ocb-05 to draft-ietf-ipwave- 1098 ipv6-over-80211ocb-06 1100 o Updated references of 802.11-OCB document from -2012 to the IEEE 1101 802.11-2016. 1103 o In the LL address section, and in SLAAC section, added references 1104 to 7217 opaque IIDs and 8064 stable IIDs. 1106 From draft-ietf-ipwave-ipv6-over-80211ocb-04 to draft-ietf-ipwave- 1107 ipv6-over-80211ocb-05 1109 o Lengthened the title and cleanded the abstract. 1111 o Added text suggesting LLs may be easy to use on OCB, rather than 1112 GUAs based on received prefix. 1114 o Added the risks of spoofing and hijacking. 1116 o Removed the text speculation on adoption of the TSA message. 1118 o Clarified that the ND protocol is used. 1120 o Clarified what it means "No association needed". 1122 o Added some text about how two STAs discover each other. 1124 o Added mention of external (OCB) and internal network (stable), in 1125 the subnet structure section. 1127 o Added phrase explaining that both .11 Data and .11 QoS Data 1128 headers are currently being used, and may be used in the future. 1130 o Moved the packet capture example into an Appendix Implementation 1131 Status. 1133 o Suggested moving the reliability requirements appendix out into 1134 another document. 1136 o Added a IANA Consiserations section, with content, requesting for 1137 a new multicast group "all OCB interfaces". 1139 o Added new OBU term, improved the RSU term definition, removed the 1140 ETTC term, replaced more occurences of 802.11p, 802.11-OCB with 1141 802.11-OCB. 1143 o References: 1145 * Added an informational reference to ETSI's IPv6-over- 1146 GeoNetworking. 1148 * Added more references to IETF and ETSI security protocols. 1150 * Updated some references from I-D to RFC, and from old RFC to 1151 new RFC numbers. 1153 * Added reference to multicast extensions to IPsec architecture 1154 RFC. 1156 * Added a reference to 2464-bis. 1158 * Removed FCC informative references, because not used. 1160 o Updated the affiliation of one author. 1162 o Reformulation of some phrases for better readability, and 1163 correction of typographical errors. 1165 From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave- 1166 ipv6-over-80211ocb-04 1168 o Removed a few informative references pointing to Dx draft IEEE 1169 1609 documents. 1171 o Removed outdated informative references to ETSI documents. 1173 o Added citations to IEEE 1609.2, .3 and .4-2016. 1175 o Minor textual issues. 1177 From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave- 1178 ipv6-over-80211ocb-03 1180 o Keep the previous text on multiple addresses, so remove talk about 1181 MIP6, NEMOv6 and MCoA. 1183 o Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon. 1185 o Clarified the figure showing Infrastructure mode and OCB mode side 1186 by side. 1188 o Added a reference to the IP Security Architecture RFC. 1190 o Detailed the IPv6-per-channel prohibition paragraph which reflects 1191 the discussion at the last IETF IPWAVE WG meeting. 1193 o Added section "Address Mapping -- Unicast". 1195 o Added the ".11 Trailer" to pictures of 802.11 frames. 1197 o Added text about SNAP carrying the Ethertype. 1199 o New RSU definition allowing for it be both a Router and not 1200 necessarily a Router some times. 1202 o Minor textual issues. 1204 From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave- 1205 ipv6-over-80211ocb-02 1207 o Replaced almost all occurences of 802.11p with 802.11-OCB, leaving 1208 only when explanation of evolution was necessary. 1210 o Shortened by removing parameter details from a paragraph in the 1211 Introduction. 1213 o Moved a reference from Normative to Informative. 1215 o Added text in intro clarifying there is no handover spec at IEEE, 1216 and that 1609.2 does provide security services. 1218 o Named the contents the fields of the EthernetII header (including 1219 the Ethertype bitstring). 1221 o Improved relationship between two paragraphs describing the 1222 increase of the Sequence Number in 802.11 header upon IP 1223 fragmentation. 1225 o Added brief clarification of "tracking". 1227 From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave- 1228 ipv6-over-80211ocb-01 1230 o Introduced message exchange diagram illustrating differences 1231 between 802.11 and 802.11 in OCB mode. 1233 o Introduced an appendix listing for information the set of 802.11 1234 messages that may be transmitted in OCB mode. 1236 o Removed appendix sections "Privacy Requirements", "Authentication 1237 Requirements" and "Security Certificate Generation". 1239 o Removed appendix section "Non IP Communications". 1241 o Introductory phrase in the Security Considerations section. 1243 o Improved the definition of "OCB". 1245 o Introduced theoretical stacked layers about IPv6 and IEEE layers 1246 including EPD. 1248 o Removed the appendix describing the details of prohibiting IPv6 on 1249 certain channels relevant to 802.11-OCB. 1251 o Added a brief reference in the privacy text about a precise clause 1252 in IEEE 1609.3 and .4. 1254 o Clarified the definition of a Road Side Unit. 1256 o Removed the discussion about security of WSA (because is non-IP). 1258 o Removed mentioning of the GeoNetworking discussion. 1260 o Moved references to scientific articles to a separate 'overview' 1261 draft, and referred to it. 1263 Appendix B. 802.11p 1265 The term "802.11p" is an earlier definition. The behaviour of 1266 "802.11p" networks is rolled in the document IEEE Std 802.11-2016. 1267 In that document the term 802.11p disappears. Instead, each 802.11p 1268 feature is conditioned by the IEEE Management Information Base (MIB) 1269 attribute "OCBActivated" [IEEE-802.11-2016]. Whenever OCBActivated 1270 is set to true the IEEE Std 802.11-OCB state is activated. For 1271 example, an 802.11 STAtion operating outside the context of a basic 1272 service set has the OCBActivated flag set. Such a station, when it 1273 has the flag set, uses a BSS identifier equal to ff:ff:ff:ff:ff:ff. 1275 Appendix C. Aspects introduced by the OCB mode to 802.11 1277 In the IEEE 802.11-OCB mode, all nodes in the wireless range can 1278 directly communicate with each other without involving authentication 1279 or association procedures. In OCB mode, the manner in which channels 1280 are selected and used is simplified compared to when in BSS mode. 1282 Contrary to BSS mode, at link layer, it is necessary to set 1283 statically the same channel number (or frequency) on two stations 1284 that need to communicate with each other (in BSS mode this channel 1285 set operation is performed automatically during 'scanning'). The 1286 manner in which stations set their channel number in OCB mode is not 1287 specified in this document. Stations STA1 and STA2 can exchange IP 1288 packets only if they are set on the same channel. At IP layer, they 1289 then discover each other by using the IPv6 Neighbor Discovery 1290 protocol. The allocation of a particular channel for a particular 1291 use is defined statically in standards authored by ETSI (in Europe), 1292 FCC in America, and similar organisations in South Korea, Japan and 1293 other parts of the world. 1295 Briefly, the IEEE 802.11-OCB mode has the following properties: 1297 o The use by each node of a 'wildcard' BSSID (i.e., each bit of the 1298 BSSID is set to 1) 1300 o No IEEE 802.11 Beacon frames are transmitted 1302 o No authentication is required in order to be able to communicate 1304 o No association is needed in order to be able to communicate 1306 o No encryption is provided in order to be able to communicate 1308 o Flag dot11OCBActivated is set to true 1310 All the nodes in the radio communication range (IP-OBU and IP-RSU) 1311 receive all the messages transmitted (IP-OBU and IP-RSU) within the 1312 radio communications range. The eventual conflict(s) are resolved by 1313 the MAC CDMA function. 1315 The message exchange diagram in Figure 3 illustrates a comparison 1316 between traditional 802.11 and 802.11 in OCB mode. The 'Data' 1317 messages can be IP packets such as HTTP or others. Other 802.11 1318 management and control frames (non IP) may be transmitted, as 1319 specified in the 802.11 standard. For information, the names of 1320 these messages as currently specified by the 802.11 standard are 1321 listed in Appendix G. 1323 STA AP STA1 STA2 1324 | | | | 1325 |<------ Beacon -------| |<------ Data -------->| 1326 | | | | 1327 |---- Probe Req. ----->| |<------ Data -------->| 1328 |<--- Probe Res. ------| | | 1329 | | |<------ Data -------->| 1330 |---- Auth Req. ------>| | | 1331 |<--- Auth Res. -------| |<------ Data -------->| 1332 | | | | 1333 |---- Asso Req. ------>| |<------ Data -------->| 1334 |<--- Asso Res. -------| | | 1335 | | |<------ Data -------->| 1336 |<------ Data -------->| | | 1337 |<------ Data -------->| |<------ Data -------->| 1339 (i) 802.11 Infrastructure mode (ii) 802.11-OCB mode 1341 Figure 3: Difference between messages exchanged on 802.11 (left) and 1342 802.11-OCB (right) 1344 The interface 802.11-OCB was specified in IEEE Std 802.11p (TM) -2010 1345 [IEEE-802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, 1346 titled "Amendment 6: Wireless Access in Vehicular Environments". 1347 Since then, this amendment has been integrated in IEEE 802.11(TM) 1348 -2012 and -2016 [IEEE-802.11-2016]. 1350 In document 802.11-2016, anything qualified specifically as 1351 "OCBActivated", or "outside the context of a basic service" set to be 1352 true, then it is actually referring to OCB aspects introduced to 1353 802.11. 1355 In order to delineate the aspects introduced by 802.11-OCB to 802.11, 1356 we refer to the earlier [IEEE-802.11p-2010]. The amendment is 1357 concerned with vehicular communications, where the wireless link is 1358 similar to that of Wireless LAN (using a PHY layer specified by 1359 802.11a/b/g/n), but which needs to cope with the high mobility factor 1360 inherent in scenarios of communications between moving vehicles, and 1361 between vehicles and fixed infrastructure deployed along roads. 1362 While 'p' is a letter identifying the Ammendment, just like 'a, b, g' 1363 and 'n' are, 'p' is concerned more with MAC modifications, and a 1364 little with PHY modifications; the others are mainly about PHY 1365 modifications. It is possible in practice to combine a 'p' MAC with 1366 an 'a' PHY by operating outside the context of a BSS with OFDM at 1367 5.4GHz and 5.9GHz. 1369 The 802.11-OCB links are specified to be compatible as much as 1370 possible with the behaviour of 802.11a/b/g/n and future generation 1371 IEEE WLAN links. From the IP perspective, an 802.11-OCB MAC layer 1372 offers practically the same interface to IP as the 802.11a/b/g/n and 1373 802.3. A packet sent by an IP-OBU may be received by one or multiple 1374 IP-RSUs. The link-layer resolution is performed by using the IPv6 1375 Neighbor Discovery protocol. 1377 To support this similarity statement (IPv6 is layered on top of LLC 1378 on top of 802.11-OCB, in the same way that IPv6 is layered on top of 1379 LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on 1380 top of 802.3 (for Ethernet)) it is useful to analyze the differences 1381 between 802.11-OCB and 802.11 specifications. During this analysis, 1382 we note that whereas 802.11-OCB lists relatively complex and numerous 1383 changes to the MAC layer (and very little to the PHY layer), there 1384 are only a few characteristics which may be important for an 1385 implementation transmitting IPv6 packets on 802.11-OCB links. 1387 The most important 802.11-OCB point which influences the IPv6 1388 functioning is the OCB characteristic; an additional, less direct 1389 influence, is the maximum bandwidth afforded by the PHY modulation/ 1390 demodulation methods and channel access specified by 802.11-OCB. The 1391 maximum bandwidth theoretically possible in 802.11-OCB is 54 Mbit/s 1392 (when using, for example, the following parameters: 20 MHz channel; 1393 modulation 64-QAM; coding rate R is 3/4); in practice of IP-over- 1394 802.11-OCB a commonly observed figure is 12Mbit/s; this bandwidth 1395 allows the operation of a wide range of protocols relying on IPv6. 1397 o Operation Outside the Context of a BSS (OCB): the (earlier 1398 802.11p) 802.11-OCB links are operated without a Basic Service Set 1399 (BSS). This means that the frames IEEE 802.11 Beacon, Association 1400 Request/Response, Authentication Request/Response, and similar, 1401 are not used. The used identifier of BSS (BSSID) has a 1402 hexadecimal value always 0xffffffffffff (48 '1' bits, represented 1403 as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' 1404 BSSID), as opposed to an arbitrary BSSID value set by 1405 administrator (e.g. 'My-Home-AccessPoint'). The OCB operation - 1406 namely the lack of beacon-based scanning and lack of 1407 authentication - should be taken into account when the Mobile IPv6 1408 protocol [RFC6275] and the protocols for IP layer security 1409 [RFC4301] are used. The way these protocols adapt to OCB is not 1410 described in this document. 1412 o Timing Advertisement: is a new message defined in 802.11-OCB, 1413 which does not exist in 802.11a/b/g/n. This message is used by 1414 stations to inform other stations about the value of time. It is 1415 similar to the time as delivered by a GNSS system (Galileo, GPS, 1416 ...) or by a cellular system. This message is optional for 1417 implementation. 1419 o Frequency range: this is a characteristic of the PHY layer, with 1420 almost no impact on the interface between MAC and IP. However, it 1421 is worth considering that the frequency range is regulated by a 1422 regional authority (ARCEP, ECC/CEPT based on ENs from ETSI, FCC, 1423 etc.); as part of the regulation process, specific applications 1424 are associated with specific frequency ranges. In the case of 1425 802.11-OCB, the regulator associates a set of frequency ranges, or 1426 slots within a band, to the use of applications of vehicular 1427 communications, in a band known as "5.9GHz". The 5.9GHz band is 1428 different from the 2.4GHz and 5GHz bands used by Wireless LAN. 1429 However, as with Wireless LAN, the operation of 802.11-OCB in 1430 "5.9GHz" bands is exempt from owning a license in EU (in US the 1431 5.9GHz is a licensed band of spectrum; for the fixed 1432 infrastructure an explicit FCC authorization is required; for an 1433 on-board device a 'licensed-by-rule' concept applies: rule 1434 certification conformity is required.) Technical conditions are 1435 different than those of the bands "2.4GHz" or "5GHz". The allowed 1436 power levels, and implicitly the maximum allowed distance between 1437 vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20 1438 dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum 1439 distance of approximately 1km, compared to approximately 50m. 1440 Additionally, specific conditions related to congestion avoidance, 1441 jamming avoidance, and radar detection are imposed on the use of 1442 DSRC (in US) and on the use of frequencies for Intelligent 1443 Transportation Systems (in EU), compared to Wireless LAN 1444 (802.11a/b/g/n). 1446 o 'Half-rate' encoding: as the frequency range, this parameter is 1447 related to PHY, and thus has not much impact on the interface 1448 between the IP layer and the MAC layer. 1450 o In vehicular communications using 802.11-OCB links, there are 1451 strong privacy requirements with respect to addressing. While the 1452 802.11-OCB standard does not specify anything in particular with 1453 respect to MAC addresses, in these settings there exists a strong 1454 need for dynamic change of these addresses (as opposed to the non- 1455 vehicular settings - real wall protection - where fixed MAC 1456 addresses do not currently pose some privacy risks). This is 1457 further described in Section 5. A relevant function is described 1458 in documents IEEE 1609.3-2016 [IEEE-1609.3] and IEEE 1609.4-2016 1459 [IEEE-1609.4]. 1461 Appendix D. Changes Needed on a software driver 802.11a to become a 1462 802.11-OCB driver 1464 The 802.11p amendment modifies both the 802.11 stack's physical and 1465 MAC layers but all the induced modifications can be quite easily 1466 obtained by modifying an existing 802.11a ad-hoc stack. 1468 Conditions for a 802.11a hardware to be 802.11-OCB compliant: 1470 o The PHY entity shall be an orthogonal frequency division 1471 multiplexing (OFDM) system. It must support the frequency bands 1472 on which the regulator recommends the use of ITS communications, 1473 for example using IEEE 802.11-OCB layer, in France: 5875MHz to 1474 5925MHz. 1476 o The OFDM system must provide a "half-clocked" operation using 10 1477 MHz channel spacings. 1479 o The chip transmit spectrum mask must be compliant to the "Transmit 1480 spectrum mask" from the IEEE 802.11p amendment (but experimental 1481 environments tolerate otherwise). 1483 o The chip should be able to transmit up to 44.8 dBm when used by 1484 the US government in the United States, and up to 33 dBm in 1485 Europe; other regional conditions apply. 1487 Changes needed on the network stack in OCB mode: 1489 o Physical layer: 1491 * The chip must use the Orthogonal Frequency Multiple Access 1492 (OFDM) encoding mode. 1494 * The chip must be set in half-mode rate mode (the internal clock 1495 frequency is divided by two). 1497 * The chip must use dedicated channels and should allow the use 1498 of higher emission powers. This may require modifications to 1499 the local computer file that describes regulatory domains 1500 rules, if used by the kernel to enforce local specific 1501 restrictions. Such modifications to the local computer file 1502 must respect the location-specific regulatory rules. 1504 MAC layer: 1506 * All management frames (beacons, join, leave, and others) 1507 emission and reception must be disabled except for frames of 1508 subtype Action and Timing Advertisement (defined below). 1510 * No encryption key or method must be used. 1512 * Packet emission and reception must be performed as in ad-hoc 1513 mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff). 1515 * The functions related to joining a BSS (Association Request/ 1516 Response) and for authentication (Authentication Request/Reply, 1517 Challenge) are not called. 1519 * The beacon interval is always set to 0 (zero). 1521 * Timing Advertisement frames, defined in the amendment, should 1522 be supported. The upper layer should be able to trigger such 1523 frames emission and to retrieve information contained in 1524 received Timing Advertisements. 1526 Appendix E. Protocol Layering 1528 A more theoretical and detailed view of layer stacking, and 1529 interfaces between the IP layer and 802.11-OCB layers, is illustrated 1530 in Figure 4. The IP layer operates on top of the EtherType Protocol 1531 Discrimination (EPD); this Discrimination layer is described in IEEE 1532 Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP 1533 (Link Layer Control Service Access Point). 1535 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1536 | IPv6 | 1537 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ 1538 { LLC_SAP } 802.11-OCB 1539 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary 1540 | EPD | | | 1541 | | MLME | | 1542 +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | 1543 | MAC Sublayer | | | 802.11-OCB 1544 | and ch. coord. | | SME | Services 1545 +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | 1546 | | PLME | | 1547 | PHY Layer | PLME_SAP | 1548 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1550 Figure 4: EtherType Protocol Discrimination 1552 Appendix F. Design Considerations 1554 The networks defined by 802.11-OCB are in many ways similar to other 1555 networks of the 802.11 family. In theory, the encapsulation of IPv6 1556 over 802.11-OCB could be very similar to the operation of IPv6 over 1557 other networks of the 802.11 family. However, the high mobility, 1558 strong link asymmetry and very short connection makes the 802.11-OCB 1559 link significantly different from other 802.11 networks. Also, the 1560 automotive applications have specific requirements for reliability, 1561 security and privacy, which further add to the particularity of the 1562 802.11-OCB link. 1564 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode 1566 For information, at the time of writing, this is the list of IEEE 1567 802.11 messages that may be transmitted in OCB mode, i.e. when 1568 dot11OCBActivated is true in a STA: 1570 o The STA may send management frames of subtype Action and, if the 1571 STA maintains a TSF Timer, subtype Timing Advertisement; 1573 o The STA may send control frames, except those of subtype PS-Poll, 1574 CF-End, and CF-End plus CFAck; 1576 o The STA may send data frames of subtype Data, Null, QoS Data, and 1577 QoS Null. 1579 Appendix H. Examples of Packet Formats 1581 This section describes an example of an IPv6 Packet captured over a 1582 IEEE 802.11-OCB link. 1584 By way of example we show that there is no modification in the 1585 headers when transmitted over 802.11-OCB networks - they are 1586 transmitted like any other 802.11 and Ethernet packets. 1588 We describe an experiment of capturing an IPv6 packet on an 1589 802.11-OCB link. In topology depicted in Figure 5, the packet is an 1590 IPv6 Router Advertisement. This packet is emitted by a Router on its 1591 802.11-OCB interface. The packet is captured on the Host, using a 1592 network protocol analyzer (e.g. Wireshark); the capture is performed 1593 in two different modes: direct mode and 'monitor' mode. The topology 1594 used during the capture is depicted below. 1596 The packet is captured on the Host. The Host is an IP-OBU containing 1597 an 802.11 interface in format PCI express (an ITRI product). The 1598 kernel runs the ath5k software driver with modifications for OCB 1599 mode. The capture tool is Wireshark. The file format for save and 1600 analyze is 'pcap'. The packet is generated by the Router. The 1601 Router is an IP-RSU (ITRI product). 1603 +--------+ +-------+ 1604 | | 802.11-OCB Link | | 1605 ---| Router |--------------------------------| Host | 1606 | | | | 1607 +--------+ +-------+ 1609 Figure 5: Topology for capturing IP packets on 802.11-OCB 1611 During several capture operations running from a few moments to 1612 several hours, no message relevant to the BSSID contexts were 1613 captured (no Association Request/Response, Authentication Req/Resp, 1614 Beacon). This shows that the operation of 802.11-OCB is outside the 1615 context of a BSSID. 1617 Overall, the captured message is identical with a capture of an IPv6 1618 packet emitted on a 802.11b interface. The contents are precisely 1619 similar. 1621 H.1. Capture in Monitor Mode 1623 The IPv6 RA packet captured in monitor mode is illustrated below. 1624 The radio tap header provides more flexibility for reporting the 1625 characteristics of frames. The Radiotap Header is prepended by this 1626 particular stack and operating system on the Host machine to the RA 1627 packet received from the network (the Radiotap Header is not present 1628 on the air). The implementation-dependent Radiotap Header is useful 1629 for piggybacking PHY information from the chip's registers as data in 1630 a packet understandable by userland applications using Socket 1631 interfaces (the PHY interface can be, for example: power levels, data 1632 rate, ratio of signal to noise). 1634 The packet present on the air is formed by IEEE 802.11 Data Header, 1635 Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. 1637 Radiotap Header v0 1638 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1639 |Header Revision| Header Pad | Header length | 1640 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1641 | Present flags | 1642 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1643 | Data Rate | Pad | 1644 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1646 IEEE 802.11 Data Header 1647 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1648 | Type/Subtype and Frame Ctrl | Duration | 1649 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1650 | Receiver Address... 1651 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1652 ... Receiver Address | Transmitter Address... 1653 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1654 ... Transmitter Address | 1655 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1656 | BSS Id... 1657 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1658 ... BSS Id | Frag Number and Seq Number | 1659 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1661 Logical-Link Control Header 1662 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1663 | DSAP |I| SSAP |C| Control field | Org. code... 1664 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1665 ... Organizational Code | Type | 1666 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1668 IPv6 Base Header 1669 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1670 |Version| Traffic Class | Flow Label | 1671 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1672 | Payload Length | Next Header | Hop Limit | 1673 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1674 | | 1675 + + 1676 | | 1677 + Source Address + 1678 | | 1679 + + 1680 | | 1681 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1682 | | 1683 + + 1684 | | 1685 + Destination Address + 1686 | | 1687 + + 1688 | | 1689 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1691 Router Advertisement 1692 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1693 | Type | Code | Checksum | 1694 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1695 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1696 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1697 | Reachable Time | 1698 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1699 | Retrans Timer | 1700 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1701 | Options ... 1702 +-+-+-+-+-+-+-+-+-+-+-+- 1704 The value of the Data Rate field in the Radiotap header is set to 6 1705 Mb/s. This indicates the rate at which this RA was received. 1707 The value of the Transmitter address in the IEEE 802.11 Data Header 1708 is set to a 48bit value. The value of the destination address is 1709 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS 1710 Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network 1711 protocol analyzer as being "broadcast". The Fragment number and 1712 sequence number fields are together set to 0x90C6. 1714 The value of the Organization Code field in the Logical-Link Control 1715 Header is set to 0x0, recognized as "Encapsulated Ethernet". The 1716 value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise 1717 #86DD), recognized as "IPv6". 1719 A Router Advertisement is periodically sent by the router to 1720 multicast group address ff02::1. It is an icmp packet type 134. The 1721 IPv6 Neighbor Discovery's Router Advertisement message contains an 1722 8-bit field reserved for single-bit flags, as described in [RFC4861]. 1724 The IPv6 header contains the link local address of the router 1725 (source) configured via EUI-64 algorithm, and destination address set 1726 to ff02::1. 1728 The Ethernet Type field in the logical-link control header is set to 1729 0x86dd which indicates that the frame transports an IPv6 packet. In 1730 the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 1731 which is the corresponding multicast MAC address. The BSS id is a 1732 broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link 1733 duration between vehicles and the roadside infrastructure, there is 1734 no need in IEEE 802.11-OCB to wait for the completion of association 1735 and authentication procedures before exchanging data. IEEE 1736 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) 1737 and may start communicating as soon as they arrive on the 1738 communication channel. 1740 H.2. Capture in Normal Mode 1742 The same IPv6 Router Advertisement packet described above (monitor 1743 mode) is captured on the Host, in the Normal mode, and depicted 1744 below. 1746 Ethernet II Header 1747 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1748 | Destination... 1749 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1750 ...Destination | Source... 1751 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1752 ...Source | 1753 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1754 | Type | 1755 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1757 IPv6 Base Header 1758 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1759 |Version| Traffic Class | Flow Label | 1760 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1761 | Payload Length | Next Header | Hop Limit | 1762 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1763 | | 1764 + + 1765 | | 1766 + Source Address + 1767 | | 1768 + + 1769 | | 1770 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1771 | | 1772 + + 1773 | | 1774 + Destination Address + 1775 | | 1776 + + 1777 | | 1778 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1780 Router Advertisement 1781 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1782 | Type | Code | Checksum | 1783 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1784 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1785 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1786 | Reachable Time | 1787 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1788 | Retrans Timer | 1789 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1790 | Options ... 1791 +-+-+-+-+-+-+-+-+-+-+-+- 1793 One notices that the Radiotap Header, the IEEE 802.11 Data Header and 1794 the Logical-Link Control Headers are not present. On the other hand, 1795 a new header named Ethernet II Header is present. 1797 The Destination and Source addresses in the Ethernet II header 1798 contain the same values as the fields Receiver Address and 1799 Transmitter Address present in the IEEE 802.11 Data Header in the 1800 "monitor" mode capture. 1802 The value of the Type field in the Ethernet II header is 0x86DD 1803 (recognized as "IPv6"); this value is the same value as the value of 1804 the field Type in the Logical-Link Control Header in the "monitor" 1805 mode capture. 1807 The knowledgeable experimenter will no doubt notice the similarity of 1808 this Ethernet II Header with a capture in normal mode on a pure 1809 Ethernet cable interface. 1811 An Adaptation layer is inserted on top of a pure IEEE 802.11 MAC 1812 layer, in order to adapt packets, before delivering the payload data 1813 to the applications. It adapts 802.11 LLC/MAC headers to Ethernet II 1814 headers. In further detail, this adaptation consists in the 1815 elimination of the Radiotap, 802.11 and LLC headers, and in the 1816 insertion of the Ethernet II header. In this way, IPv6 runs straight 1817 over LLC over the 802.11-OCB MAC layer; this is further confirmed by 1818 the use of the unique Type 0x86DD. 1820 Appendix I. Extra Terminology 1822 The following terms are defined outside the IETF. They are used to 1823 define the main terms in the main terminology section Section 2. 1825 DSRC (Dedicated Short Range Communication): a term defined outside 1826 the IETF. The US Federal Communications Commission (FCC) Dedicated 1827 Short Range Communication (DSRC) is defined in the Code of Federal 1828 Regulations (CFR) 47, Parts 90 and 95. This Code is referred in the 1829 definitions below. At the time of the writing of this Internet 1830 Draft, the last update of this Code was dated October 1st, 2010. 1832 DSRCS (Dedicated Short-Range Communications Services): a term defined 1833 outside the IETF. The use of radio techniques to transfer data over 1834 short distances between roadside and mobile units, between mobile 1835 units, and between portable and mobile units to perform operations 1836 related to the improvement of traffic flow, traffic safety, and other 1837 intelligent transportation service applications in a variety of 1838 environments. DSRCS systems may also transmit status and 1839 instructional messages related to the units involve. [Ref. 47 CFR 1840 90.7 - Definitions] 1841 OBU (On-Board Unit): a term defined outside the IETF. An On-Board 1842 Unit is a DSRCS transceiver that is normally mounted in or on a 1843 vehicle, or which in some instances may be a portable unit. An OBU 1844 can be operational while a vehicle or person is either mobile or 1845 stationary. The OBUs receive and contend for time to transmit on one 1846 or more radio frequency (RF) channels. Except where specifically 1847 excluded, OBU operation is permitted wherever vehicle operation or 1848 human passage is permitted. The OBUs mounted in vehicles are 1849 licensed by rule under part 95 of the respective chapter and 1850 communicate with Roadside Units (RSUs) and other OBUs. Portable OBUs 1851 are also licensed by rule under part 95 of the respective chapter. 1852 OBU operations in the Unlicensed National Information Infrastructure 1853 (UNII) Bands follow the rules in those bands. - [CFR 90.7 - 1854 Definitions]. 1856 RSU (Road-Side Unit): a term defined outside of IETF. A Roadside 1857 Unit is a DSRC transceiver that is mounted along a road or pedestrian 1858 passageway. An RSU may also be mounted on a vehicle or is hand 1859 carried, but it may only operate when the vehicle or hand- carried 1860 unit is stationary. Furthermore, an RSU operating under the 1861 respectgive part is restricted to the location where it is licensed 1862 to operate. However, portable or hand-held RSUs are permitted to 1863 operate where they do not interfere with a site-licensed operation. 1864 A RSU broadcasts data to OBUs or exchanges data with OBUs in its 1865 communications zone. An RSU also provides channel assignments and 1866 operating instructions to OBUs in its communications zone, when 1867 required. - [CFR 90.7 - Definitions]. 1869 Appendix J. Neighbor Discovery (ND) Potential Issues in Wireless Links 1871 IPv6 Neighbor Discovery (IPv6 ND) [RFC4861][RFC4862] was designed for 1872 point-to-point and transit links such as Ethernet, with the 1873 expectation of a cheap and reliable support for multicast from the 1874 lower layer. Section 3.2 of RFC 4861 indicates that the operation on 1875 Shared Media and on non-broadcast multi-access (NBMA) networks 1876 require additional support, e.g., for Address Resolution (AR) and 1877 duplicate address detection (DAD), which depend on multicast. An 1878 infrastructureless radio network such as OCB shares properties with 1879 both Shared Media and NBMA networks, and then adds its own 1880 complexity, e.g., from movement and interference that allow only 1881 transient and non-transitive reachability between any set of peers. 1883 The uniqueness of an address within a scoped domain is a key pillar 1884 of IPv6 and the base for unicast IP communication. RFC 4861 details 1885 the DAD method to avoid that an address is duplicated. For a link 1886 local address, the scope is the link, whereas for a global address 1887 the scope is much larger. The underlying assumption for DAD to 1888 operate correctly is that the node that owns an IPv6 address can 1889 reach any other node within the scope at the time it claims its 1890 address, which is done by sending a NS multicast message, and can 1891 hear any future claim for that address by another party within the 1892 scope for the duration of the address ownership. 1894 In the case of OCB, there is a potentially a need to define a scope 1895 that is compatible with DAD, and that cannot be the set of nodes that 1896 a transmitter can reach at a particular time, because that set varies 1897 all the time and does not meet the DAD requirements for a link local 1898 address that could possibly be used anytime, anywhere. The generic 1899 expectation of a reliable multicast is not ensured, and the operation 1900 of DAD and AR (Address Resolution) as specificed by RFC 4861 cannot 1901 be guaranteed. Moreoever, multicast transmissions that rely on 1902 broadcast are not only unreliable but are also often detrimental to 1903 unicast traffic (see [draft-ietf-mboned-ieee802-mcast-problems]). 1905 Early experiences indicate that it should be possible to exchange 1906 IPv6 packets over OCB while relying on IPv6 ND alone for DAD and AR 1907 (Address Resolution). In the absence of a correct DAD operation, a 1908 node that relies only on IPv6 ND for AR and DAD over OCB should 1909 ensure that the addresses that it uses are unique by means others 1910 than DAD. It must be noted that deriving an IPv6 address from a 1911 globally unique MAC address has this property but may yield privacy 1912 issues. 1914 RFC 8505 provides a more recent approach to IPv6 ND and in particular 1915 DAD. RFC 8505 is designed to fit wireless and otherwise constrained 1916 networks whereby multicast and/or continuous access to the medium may 1917 not be guaranteed. RFC 8505 Section 5.6 "Link-Local Addresses and 1918 Registration" indicates that the scope of uniqueness for a link local 1919 address is restricted to a pair of nodes that use it to communicate, 1920 and provides a method to assert the uniqueness and resolve the link- 1921 Layer address using a unicast exchange. 1923 RFC 8505 also enables a router (acting as a 6LR) to own a prefix and 1924 act as a registrar (acting as a 6LBR) for addresses within the 1925 associated subnet. A peer host (acting as a 6LN) registers an 1926 address derived from that prefix and can use it for the lifetime of 1927 the registration. The prefix is advertised as not onlink, which 1928 means that the 6LN uses the 6LR to relay its packets within the 1929 subnet, and participation to the subnet is constrained to the time of 1930 reachability to the 6LR. Note that RSU that provides internet 1931 connectivity MAY announce a default router preference [RFC 4191], 1932 whereas a car that does not provide that connectivity MUST NOT do so. 1933 This operation presents similarities with that of an access point, 1934 but at Layer-3. This is why RFC 8505 well-suited for wireless in 1935 general. 1937 Support of RFC 8505 is may be implemented on OCB. OCB nodes that 1938 support RFC 8505 would support the 6LN operation in order to act as a 1939 host, and may support the 6LR and 6LBR operations in order to act as 1940 a router and in particular own a prefix that can be used by RFC 1941 8505-compliant hosts for address autoconfiguration and registration. 1943 Authors' Addresses 1945 Alexandre Petrescu 1946 CEA, LIST 1947 CEA Saclay 1948 Gif-sur-Yvette , Ile-de-France 91190 1949 France 1951 Phone: +33169089223 1952 Email: Alexandre.Petrescu@cea.fr 1954 Nabil Benamar 1955 Moulay Ismail University 1956 Morocco 1958 Phone: +212670832236 1959 Email: n.benamar@est.umi.ac.ma 1961 Jerome Haerri 1962 Eurecom 1963 Sophia-Antipolis 06904 1964 France 1966 Phone: +33493008134 1967 Email: Jerome.Haerri@eurecom.fr 1969 Jong-Hyouk Lee 1970 Sangmyung University 1971 31, Sangmyeongdae-gil, Dongnam-gu 1972 Cheonan 31066 1973 Republic of Korea 1975 Email: jonghyouk@smu.ac.kr 1976 Thierry Ernst 1977 YoGoKo 1978 France 1980 Email: thierry.ernst@yogoko.fr