idnits 2.17.1 draft-ietf-ipwave-ipv6-over-80211ocb-33.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == The expression 'MAY NOT', while looking like RFC 2119 requirements text, is not defined in RFC 2119, and should not be used. Consider using 'MUST NOT' instead (if that is what you mean). 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 (December 17, 2018) is 1957 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) ** 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reference: RFC 7042 (Obsoleted by RFC 9542) ** Downref: Normative reference to an Informational RFC: RFC 7721 == Outdated reference: A later version (-15) exists of draft-ietf-mboned-ieee802-mcast-problems-04 Summary: 5 errors (**), 0 flaws (~~), 3 warnings (==), 2 comments (--).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: June 20, 2019 Moulay Ismail University 6 J. Haerri 7 Eurecom 8 J. Lee 9 Sangmyung University 10 T. Ernst 11 YoGoKo 12 December 17, 2018 14 Transmission of IPv6 Packets over IEEE 802.11 Networks operating in mode 15 Outside the Context of a Basic Service Set (IPv6-over-80211-OCB) 16 draft-ietf-ipwave-ipv6-over-80211ocb-33 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 June 20, 2019. 47 Copyright Notice 49 Copyright (c) 2018 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (https://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with respect 57 to this document. Code Components extracted from this document must 58 include Simplified BSD License text as described in Section 4.e of 59 the Trust Legal Provisions and are provided without warranty as 60 described in the Simplified BSD License. 62 Table of Contents 64 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 65 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 66 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 4 67 4. IPv6 over 802.11-OCB . . . . . . . . . . . . . . . . . . . . 4 68 4.1. Maximum Transmission Unit (MTU) . . . . . . . . . . . . . 4 69 4.2. Frame Format . . . . . . . . . . . . . . . . . . . . . . 5 70 4.2.1. Ethernet Adaptation Layer . . . . . . . . . . . . . . 5 71 4.3. Link-Local Addresses . . . . . . . . . . . . . . . . . . 7 72 4.4. Address Mapping . . . . . . . . . . . . . . . . . . . . . 7 73 4.4.1. Address Mapping -- Unicast . . . . . . . . . . . . . 7 74 4.4.2. Address Mapping -- Multicast . . . . . . . . . . . . 7 75 4.5. Stateless Autoconfiguration . . . . . . . . . . . . . . . 7 76 4.6. Subnet Structure . . . . . . . . . . . . . . . . . . . . 9 77 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9 78 5.1. Privacy Considerations . . . . . . . . . . . . . . . . . 10 79 5.2. MAC Address and Interface ID Generation . . . . . . . . . 11 80 5.3. Pseudonym Handling . . . . . . . . . . . . . . . . . . . 11 81 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 82 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 12 83 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 84 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 85 9.1. Normative References . . . . . . . . . . . . . . . . . . 13 86 9.2. Informative References . . . . . . . . . . . . . . . . . 15 87 Appendix A. ChangeLog . . . . . . . . . . . . . . . . . . . . . 17 88 Appendix B. 802.11p . . . . . . . . . . . . . . . . . . . . . . 27 89 Appendix C. Aspects introduced by the OCB mode to 802.11 . . . . 27 90 Appendix D. Changes Needed on a software driver 802.11a to 91 become a 802.11-OCB driver . . . 31 92 Appendix E. Protocol Layering . . . . . . . . . . . . . . . . . 32 93 Appendix F. Design Considerations . . . . . . . . . . . . . . . 33 94 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode . . . . 33 95 Appendix H. Examples of Packet Formats . . . . . . . . . . . . . 34 96 H.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . 35 97 H.2. Capture in Normal Mode . . . . . . . . . . . . . . . . . 37 98 Appendix I. Extra Terminology . . . . . . . . . . . . . . . . . 39 99 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40 101 1. Introduction 103 This document describes the transmission of IPv6 packets on IEEE Std 104 802.11-OCB networks [IEEE-802.11-2016] (a.k.a "802.11p" see 105 Appendix B, Appendix C and Appendix D). This involves the layering 106 of IPv6 networking on top of the IEEE 802.11 MAC layer, with an LLC 107 layer. Compared to running IPv6 over the Ethernet MAC layer, there 108 is no modification expected to IEEE Std 802.11 MAC and Logical Link 109 sublayers: IPv6 works fine directly over 802.11-OCB too, with an LLC 110 layer. 112 The IPv6 network layer operates on 802.11-OCB in the same manner as 113 operating on Ethernet, but there are two kinds of exceptions: 115 o Exceptions due to different operation of IPv6 network layer on 116 802.11 than on Ethernet. To satisfy these exceptions, this 117 document describes an Ethernet Adaptation Layer between Ethernet 118 headers and 802.11 headers. The Ethernet Adaptation Layer is 119 described Section 4.2.1. The operation of IP on Ethernet is 120 described in [RFC1042], [RFC2464] and 121 [I-D.hinden-6man-rfc2464bis]. 123 o Exceptions due to the OCB nature of 802.11-OCB compared to 802.11. 124 This has impacts on security, privacy, subnet structure and 125 movement detection. For security and privacy recommendations see 126 Section 5 and Section 4.5. The subnet structure is described in 127 Section 4.6. The movement detection on OCB links is not described 128 in this document. 130 In the published literature, many documents describe aspects and 131 problems related to running IPv6 over 802.11-OCB: 132 [I-D.ietf-ipwave-vehicular-networking-survey]. 134 2. Terminology 136 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 137 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 138 document are to be interpreted as described in RFC 2119 [RFC2119]. 140 IP-OBU (Internet Protocol On-Board Unit): an IP-OBU is a computer 141 situated in a vehicle such as an automobile, bicycle, or similar. It 142 has at least one IP interface that runs in mode OCB of 802.11, and 143 that has an "OBU" transceiver. See the definition of the term "OBU" 144 in section Appendix I. 146 IP-RSU (IP Road-Side Unit): an IP-RSU is situated along the road. It 147 has at least two distinct IP-enabled interfaces; the wireless PHY/MAC 148 layer of at least one of its IP-enabled interfaces is configured to 149 operate in 802.11-OCB mode. An IP-RSU communicates with the IP-OBU 150 in the vehicle over 802.11 wireless link operating in OCB mode. An 151 IP-RSU is similar to an Access Network Router (ANR) defined in 152 [RFC3753], and a Wireless Termination Point (WTP) defined in 153 [RFC5415]. 155 OCB (outside the context of a basic service set - BSS): A mode of 156 operation in which a STA is not a member of a BSS and does not 157 utilize IEEE Std 802.11 authentication, association, or data 158 confidentiality. 160 802.11-OCB: mode specified in IEEE Std 802.11-2016 when the MIB 161 attribute dot11OCBActivited is true. Note: compliance with standards 162 and regulations set in different countries when using the 5.9GHz 163 frequency band is required. 165 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 167 The IEEE 802.11-OCB Networks are used for vehicular communications, 168 as 'Wireless Access in Vehicular Environments'. The IP communication 169 scenarios for these environments have been described in several 170 documents; in particular, we refer the reader to 171 [I-D.ietf-ipwave-vehicular-networking-survey], that lists some 172 scenarios and requirements for IP in Intelligent Transportation 173 Systems. 175 The link model is the following: STA --- 802.11-OCB --- STA. In 176 vehicular networks, STAs can be IP-RSUs and/or IP-OBUs. While 177 802.11-OCB is clearly specified, and the use of IPv6 over such link 178 is not radically new, the operating environment (vehicular networks) 179 brings in new perspectives. 181 4. IPv6 over 802.11-OCB 183 4.1. Maximum Transmission Unit (MTU) 185 The default MTU for IP packets on 802.11-OCB MUST be 1500 octets. It 186 is the same value as IPv6 packets on Ethernet links, as specified in 187 [RFC2464]. This value of the MTU respects the recommendation that 188 every link on the Internet must have a minimum MTU of 1280 octets 189 (stated in [RFC8200], and the recommendations therein, especially 190 with respect to fragmentation). 192 4.2. Frame Format 194 IP packets MUST be transmitted over 802.11-OCB media as QoS Data 195 frames whose format is specified in IEEE Std 802.11. 197 The IPv6 packet transmitted on 802.11-OCB MUST be immediately 198 preceded by a Logical Link Control (LLC) header and an 802.11 header. 199 In the LLC header, and in accordance with the EtherType Protocol 200 Discrimination (EPD, see Appendix E), the value of the Type field 201 MUST be set to 0x86DD (IPv6). In the 802.11 header, the value of the 202 Subtype sub-field in the Frame Control field MUST be set to 8 (i.e. 203 'QoS Data'); the value of the Traffic Identifier (TID) sub-field of 204 the QoS Control field of the 802.11 header MUST be set to binary 001 205 (i.e. User Priority 'Background', QoS Access Category 'AC_BK'). 207 To simplify the Application Programming Interface (API) between the 208 operating system and the 802.11-OCB media, device drivers MAY 209 implement an Ethernet Adaptation Layer that translates Ethernet II 210 frames to the 802.11 format and vice versa. An Ethernet Adaptation 211 Layer is described in Section 4.2.1. 213 4.2.1. Ethernet Adaptation Layer 215 An 'adaptation' layer is inserted between a MAC layer and the 216 Networking layer. This is used to transform some parameters between 217 their form expected by the IP stack and the form provided by the MAC 218 layer. 220 An Ethernet Adaptation Layer makes an 802.11 MAC look to IP 221 Networking layer as a more traditional Ethernet layer. At reception, 222 this layer takes as input the IEEE 802.11 header and the Logical-Link 223 Layer Control Header and produces an Ethernet II Header. At sending, 224 the reverse operation is performed. 226 The operation of the Ethernet Adaptation Layer is depicted by the 227 double arrow in Figure 1. 229 +------------------+------------+-------------+---------+-----------+ 230 | 802.11 header | LLC Header | IPv6 Header | Payload |.11 Trailer| 231 +------------------+------------+-------------+---------+-----------+ 232 \ / \ / 233 --------------------------- -------- 234 \---------------------------------------------/ 235 ^ 236 | 237 802.11-to-Ethernet Adaptation Layer 238 | 239 v 240 +---------------------+-------------+---------+ 241 | Ethernet II Header | IPv6 Header | Payload | 242 +---------------------+-------------+---------+ 244 Figure 1: Operation of the Ethernet Adaptation Layer 246 The Receiver and Transmitter Address fields in the 802.11 header MUST 247 contain the same values as the Destination and the Source Address 248 fields in the Ethernet II Header, respectively. The value of the 249 Type field in the LLC Header MUST be the same as the value of the 250 Type field in the Ethernet II Header. That value MUST be set to 251 0x86DD (IPv6). 253 The ".11 Trailer" contains solely a 4-byte Frame Check Sequence. 255 The placement of IPv6 networking layer on Ethernet Adaptation Layer 256 is illustrated in Figure 2. 258 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 259 | IPv6 | 260 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 261 | Ethernet Adaptation Layer | 262 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 263 | 802.11 MAC | 264 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 265 | 802.11 PHY | 266 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 268 Figure 2: Ethernet Adaptation Layer stacked with other layers 270 (in the above figure, a 802.11 profile is represented; this is used 271 also for 802.11-OCB profile.) 273 4.3. Link-Local Addresses 275 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 276 MAY be assigned to an 802.11-OCB interface. Among these types of 277 addresses only the IPv6 link-local addresses MAY be formed using an 278 EUI-64 identifier. 280 If the IPv6 link-local address is formed using an EUI-64 identifier, 281 then the mechanism of forming that address is the same mechanism as 282 used to form an IPv6 link-local address on Ethernet links. This 283 mechanism is described in section 5 of [RFC2464]. 285 For privacy, the link-local address MAY be formed according to the 286 mechanisms described in Section 5.2. 288 4.4. Address Mapping 290 Unicast and multicast address mapping MUST follow the procedures 291 specified for Ethernet interfaces in sections 6 and 7 of [RFC2464]. 293 4.4.1. Address Mapping -- Unicast 295 The procedure for mapping IPv6 unicast addresses into Ethernet link- 296 layer addresses is described in [RFC4861]. 298 4.4.2. Address Mapping -- Multicast 300 The multicast address mapping is performed according to the method 301 specified in section 7 of [RFC2464]. The meaning of the value "3333" 302 mentioned in that section 7 of [RFC2464] is defined in section 2.3.1 303 of [RFC7042]. 305 Transmitting IPv6 packets to multicast destinations over 802.11 links 306 proved to have some performance issues 307 [I-D.perkins-intarea-multicast-ieee802], 308 [I-D.ietf-mboned-ieee802-mcast-problems]. These issues may be 309 exacerbated in OCB mode. Solutions for these problems SHOULD 310 consider the OCB mode of operation. 312 4.5. Stateless Autoconfiguration 314 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 315 MAY be assigned to an 802.11-OCB interface. This section describes 316 the formation of Interface Identifiers for IPv6 addresses of type 317 'Global' or 'Unique Local'. For Interface Identifiers for IPv6 318 address of type 'Link-Local' see Section 4.3. 320 The Interface Identifier for an 802.11-OCB interface is formed using 321 the same rules as the Interface Identifier for an Ethernet interface; 322 the RECOMMENDED method for forming stable Interface Identifiers 323 (IIDs) is described in [RFC8064]. The method of forming IIDs 324 described in section 4 of [RFC2464] MAY be used during transition 325 time. 327 The bits in the Interface Identifier have no generic meaning and the 328 identifier should be treated as an opaque value. The bits 329 'Universal' and 'Group' in the identifier of an 802.11-OCB interface 330 are significant, as this is an IEEE link-layer address. The details 331 of this significance are described in [RFC7136]. If semantically 332 opaque Interface Identifiers are needed, a potential method for 333 generating semantically opaque Interface Identifiers with IPv6 334 Stateless Address Autoconfiguration is given in [RFC7217]. 336 Semantically opaque Interface Identifiers, instead of meaningful 337 Interface Identifiers derived from a valid and meaningful MAC address 338 ([RFC2464], section 4), MAY be needed in order to avoid certain 339 privacy risks. 341 The IPv6 packets can be captured easily in the Internet and on-link 342 in public roads. For this reason, an attacker may realize many 343 attacks on privacy. One such attack on 802.11-OCB is to capture, 344 store and correlate Company ID information present in MAC addresses 345 of many cars (e.g. listen for Router Advertisements, or other IPv6 346 application data packets, and record the value of the source address 347 in these packets). Further correlation of this information with 348 other data captured by other means, or other visual information (car 349 color, others) MAY constitute privacy risks. 351 In order to avoid these risks, opaque Interface Identifiers MAY be 352 formed according to rules described in [RFC7217]. These opaque 353 Interface Identifiers are formed starting from identifiers different 354 than the MAC addresses, and from cryptographically strong material. 355 Thus, privacy sensitive information is absent from Interface IDs, and 356 it is impossible to calculate the initial value from which the 357 Interface ID was calculated. 359 Some applications that use IPv6 packets on 802.11-OCB links (among 360 other link types) may benefit from IPv6 addresses whose Interface 361 Identifiers don't change too often. It is RECOMMENDED to use the 362 mechanisms described in RFC 7217 to permit the use of Stable 363 Interface Identifiers that do not change within one subnet prefix. A 364 possible source for the Net-Iface Parameter is a virtual interface 365 name, or logical interface name, that is decided by a local 366 administrator. 368 The way Interface Identifiers are used MAY involve risks to privacy, 369 as described in Section 5.1. 371 4.6. Subnet Structure 373 A subnet is formed by the external 802.11-OCB interfaces of vehicles 374 that are in close range (not by their in-vehicle interfaces). This 375 subnet MUST use at least the link-local prefix fe80::/10 and the 376 interfaces MUST be assigned IPv6 addresses of type link-local. 378 The structure of this subnet is ephemeral, in that it is strongly 379 influenced by the mobility of vehicles: the 802.11 hidden node 380 effects appear; the 802.11 networks in OCB mode may be considered as 381 'ad-hoc' networks with an addressing model as described in [RFC5889]. 382 On another hand, the structure of the internal subnets in each car is 383 relatively stable. 385 As recommended in [RFC5889], when the timing requirements are very 386 strict (e.g. fast drive through IP-RSU coverage), no on-link subnet 387 prefix should be configured on an 802.11-OCB interface. In such 388 cases, the exclusive use of IPv6 link-local addresses is RECOMMENDED. 390 Additionally, even if the timing requirements are not very strict 391 (e.g. the moving subnet formed by two following vehicles is stable, a 392 fixed IP-RSU is absent), the subnet is disconnected from the Internet 393 (a default route is absent), and the addressing peers are equally 394 qualified (impossible to determine that some vehicle owns and 395 distributes addresses to others) the use of link-local addresses is 396 RECOMMENDED. 398 The Neighbor Discovery protocol (ND) [RFC4861] MUST be used over 399 802.11-OCB links. 401 Protocols like Mobile IPv6 [RFC6275] and DNAv6 [RFC6059], which 402 depend on timely movement detection, might need additional tuning 403 work to handle the lack of link-layer notifications during handover. 404 This is for further study. 406 5. Security Considerations 408 Any security mechanism at the IP layer or above that may be carried 409 out for the general case of IPv6 may also be carried out for IPv6 410 operating over 802.11-OCB. 412 The OCB operation is stripped off of all existing 802.11 link-layer 413 security mechanisms. There is no encryption applied below the 414 network layer running on 802.11-OCB. At application layer, the IEEE 415 1609.2 document [IEEE-1609.2] does provide security services for 416 certain applications to use; application-layer mechanisms are out-of- 417 scope of this document. On another hand, a security mechanism 418 provided at networking layer, such as IPsec [RFC4301], may provide 419 data security protection to a wider range of applications. 421 802.11-OCB does not provide any cryptographic protection, because it 422 operates outside the context of a BSS (no Association Request/ 423 Response, no Challenge messages). Any attacker can therefore just 424 sit in the near range of vehicles, sniff the network (just set the 425 interface card's frequency to the proper range) and perform attacks 426 without needing to physically break any wall. Such a link is less 427 protected than commonly used links (wired link or protected 802.11). 429 The potential attack vectors are: MAC address spoofing, IP address 430 and session hijacking, and privacy violation Section 5.1. 432 Within the IPsec Security Architecture [RFC4301], the IPsec AH and 433 ESP headers [RFC4302] and [RFC4303] respectively, its multicast 434 extensions [RFC5374], HTTPS [RFC2818] and SeND [RFC3971] protocols 435 can be used to protect communications. Further, the assistance of 436 proper Public Key Infrastructure (PKI) protocols [RFC4210] is 437 necessary to establish credentials. More IETF protocols are 438 available in the toolbox of the IP security protocol designer. 439 Certain ETSI protocols related to security protocols in Intelligent 440 Transportation Systems are described in [ETSI-sec-archi]. 442 5.1. Privacy Considerations 444 As with all Ethernet and 802.11 interface identifiers ([RFC7721]), 445 the identifier of an 802.11-OCB interface may involve privacy, MAC 446 address spoofing and IP address hijacking risks. A vehicle embarking 447 an IP-OBU whose egress interface is 802.11-OCB may expose itself to 448 eavesdropping and subsequent correlation of data; this may reveal 449 data considered private by the vehicle owner; there is a risk of 450 being tracked. In outdoors public environments, where vehicles 451 typically circulate, the privacy risks are more important than in 452 indoors settings. It is highly likely that attacker sniffers are 453 deployed along routes which listen for IEEE frames, including IP 454 packets, of vehicles passing by. For this reason, in the 802.11-OCB 455 deployments, there is a strong necessity to use protection tools such 456 as dynamically changing MAC addresses Section 5.2, semantically 457 opaque Interface Identifiers and stable Interface Identifiers 458 Section 4.5. This may help mitigate privacy risks to a certain 459 level. 461 5.2. MAC Address and Interface ID Generation 463 In 802.11-OCB networks, the MAC addresses MAY change during well 464 defined renumbering events. In the moment the MAC address is changed 465 on an 802.11-OCB interface all the Interface Identifiers of IPv6 466 addresses assigned to that interface MUST change. 468 The policy dictating when the MAC address is changed on the 469 802.11-OCB interface is to-be-determined. For more information on 470 the motivation of this policy please refer to the privacy discussion 471 in Appendix C. 473 A 'randomized' MAC address has the following characteristics: 475 o Bit "Local/Global" set to "locally admninistered". 477 o Bit "Unicast/Multicast" set to "Unicast". 479 o The 46 remaining bits are set to a random value, using a random 480 number generator that meets the requirements of [RFC4086]. 482 To meet the randomization requirements for the 46 remaining bits, a 483 hash function may be used. For example, the SHA256 hash function may 484 be used with input a 256 bit local secret, the 'nominal' MAC Address 485 of the interface, and a representation of the date and time of the 486 renumbering event. 488 A randomized Interface ID has the same characteristics of a 489 randomized MAC address, except the length in bits. A MAC address 490 SHOULD be of length 48 decimal. An Interface ID SHOULD be of length 491 64 decimal for all types of IPv6 addresses. In the particular case 492 of IPv6 link-local addresses, the length of the Interface ID MAY be 493 118 decimal. 495 5.3. Pseudonym Handling 497 The demand for privacy protection of vehicles' and drivers' 498 identities, which could be granted by using a pseudonym or alias 499 identity at the same time, may hamper the required confidentiality of 500 messages and trust between participants - especially in safety 501 critical vehicular communication. 503 o Particular challenges arise when the pseudonymization mechanism 504 used relies on (randomized) re-addressing. 506 o A proper pseudonymization tool operated by a trusted third party 507 may be needed to ensure both aspects simultaneously (privacy 508 protection on one hand and trust between participants on another 509 hand). 511 o This is discussed in Section 4.5 and Section 5 of this document. 513 o Pseudonymity is also discussed in 514 [I-D.ietf-ipwave-vehicular-networking-survey] in its sections 515 4.2.4 and 5.1.2. 517 6. IANA Considerations 519 No request to IANA. 521 7. Contributors 523 Christian Huitema, Tony Li. 525 Romain Kuntz contributed extensively about IPv6 handovers between 526 links running outside the context of a BSS (802.11-OCB links). 528 Tim Leinmueller contributed the idea of the use of IPv6 over 529 802.11-OCB for distribution of certificates. 531 Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey 532 Voronov provided significant feedback on the experience of using IP 533 messages over 802.11-OCB in initial trials. 535 Michelle Wetterwald contributed extensively the MTU discussion, 536 offered the ETSI ITS perspective, and reviewed other parts of the 537 document. 539 8. Acknowledgements 541 The authors would like to thank Witold Klaudel, Ryuji Wakikawa, 542 Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan 543 Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray 544 Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, 545 Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne, 546 Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark, 547 Bob Moskowitz, Andrew Dryden, Georg Mayer, Dorothy Stanley, Sandra 548 Cespedes, Mariano Falcitelli, Sri Gundavelli, Abdussalam Baryun, 549 Margaret Cullen, Erik Kline, Carlos Jesus Bernardos Cano, Ronald in 550 't Velt, Katrin Sjoberg, Roland Bless, Tijink Jasja, Kevin Smith, 551 Brian Carpenter, Julian Reschke, Mikael Abrahamsson, Dirk von Hugo, 552 Lorenzo Colitti and William Whyte. Their valuable comments clarified 553 particular issues and generally helped to improve the document. 555 Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB 556 drivers for linux and described how. 558 For the multicast discussion, the authors would like to thank Owen 559 DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and 560 participants to discussions in network working groups. 562 The authors would like to thank participants to the Birds-of- 563 a-Feather "Intelligent Transportation Systems" meetings held at IETF 564 in 2016. 566 Human Rights Protocol Considerations review by Amelia Andersdotter. 568 9. References 570 9.1. Normative References 572 [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission 573 of IP datagrams over IEEE 802 networks", STD 43, RFC 1042, 574 DOI 10.17487/RFC1042, February 1988, 575 . 577 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 578 Requirement Levels", BCP 14, RFC 2119, 579 DOI 10.17487/RFC2119, March 1997, 580 . 582 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 583 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 584 . 586 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 587 DOI 10.17487/RFC2818, May 2000, 588 . 590 [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related 591 Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, 592 . 594 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 595 "SEcure Neighbor Discovery (SEND)", RFC 3971, 596 DOI 10.17487/RFC3971, March 2005, 597 . 599 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 600 "Randomness Requirements for Security", BCP 106, RFC 4086, 601 DOI 10.17487/RFC4086, June 2005, 602 . 604 [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast 605 Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005, 606 . 608 [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, 609 "Internet X.509 Public Key Infrastructure Certificate 610 Management Protocol (CMP)", RFC 4210, 611 DOI 10.17487/RFC4210, September 2005, 612 . 614 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 615 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 616 2006, . 618 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 619 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 620 December 2005, . 622 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 623 DOI 10.17487/RFC4302, December 2005, 624 . 626 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 627 RFC 4303, DOI 10.17487/RFC4303, December 2005, 628 . 630 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 631 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 632 DOI 10.17487/RFC4861, September 2007, 633 . 635 [RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast 636 Extensions to the Security Architecture for the Internet 637 Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008, 638 . 640 [RFC5415] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, 641 Ed., "Control And Provisioning of Wireless Access Points 642 (CAPWAP) Protocol Specification", RFC 5415, 643 DOI 10.17487/RFC5415, March 2009, 644 . 646 [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing 647 Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889, 648 September 2010, . 650 [RFC6059] Krishnan, S. and G. Daley, "Simple Procedures for 651 Detecting Network Attachment in IPv6", RFC 6059, 652 DOI 10.17487/RFC6059, November 2010, 653 . 655 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 656 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 657 2011, . 659 [RFC7042] Eastlake 3rd, D. and J. Abley, "IANA Considerations and 660 IETF Protocol and Documentation Usage for IEEE 802 661 Parameters", BCP 141, RFC 7042, DOI 10.17487/RFC7042, 662 October 2013, . 664 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 665 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 666 February 2014, . 668 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 669 Interface Identifiers with IPv6 Stateless Address 670 Autoconfiguration (SLAAC)", RFC 7217, 671 DOI 10.17487/RFC7217, April 2014, 672 . 674 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 675 Considerations for IPv6 Address Generation Mechanisms", 676 RFC 7721, DOI 10.17487/RFC7721, March 2016, 677 . 679 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 680 "Recommendation on Stable IPv6 Interface Identifiers", 681 RFC 8064, DOI 10.17487/RFC8064, February 2017, 682 . 684 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 685 (IPv6) Specification", STD 86, RFC 8200, 686 DOI 10.17487/RFC8200, July 2017, 687 . 689 9.2. Informative References 691 [ETSI-sec-archi] 692 "ETSI TS 102 940 V1.2.1 (2016-11), ETSI Technical 693 Specification, Intelligent Transport Systems (ITS); 694 Security; ITS communications security architecture and 695 security management, November 2016. Downloaded on 696 September 9th, 2017, freely available from ETSI website at 697 URL http://www.etsi.org/deliver/ 698 etsi_ts/102900_102999/102940/01.02.01_60/ 699 ts_102940v010201p.pdf". 701 [I-D.hinden-6man-rfc2464bis] 702 Crawford, M. and R. Hinden, "Transmission of IPv6 Packets 703 over Ethernet Networks", draft-hinden-6man-rfc2464bis-02 704 (work in progress), March 2017. 706 [I-D.ietf-ipwave-vehicular-networking-survey] 707 Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M. 708 Wetterwald, "Survey on IP-based Vehicular Networking for 709 Intelligent Transportation Systems", draft-ietf-ipwave- 710 vehicular-networking-survey-00 (work in progress), July 711 2017. 713 [I-D.ietf-mboned-ieee802-mcast-problems] 714 Perkins, C., McBride, M., Stanley, D., Kumari, W., and J. 715 Zuniga, "Multicast Considerations over IEEE 802 Wireless 716 Media", draft-ietf-mboned-ieee802-mcast-problems-04 (work 717 in progress), November 2018. 719 [I-D.perkins-intarea-multicast-ieee802] 720 Perkins, C., Stanley, D., Kumari, W., and J. Zuniga, 721 "Multicast Considerations over IEEE 802 Wireless Media", 722 draft-perkins-intarea-multicast-ieee802-03 (work in 723 progress), July 2017. 725 [IEEE-1609.2] 726 "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access 727 in Vehicular Environments (WAVE) -- Security Services for 728 Applications and Management Messages. Example URL 729 http://ieeexplore.ieee.org/document/7426684/ accessed on 730 August 17th, 2017.". 732 [IEEE-1609.3] 733 "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access 734 in Vehicular Environments (WAVE) -- Networking Services. 735 Example URL http://ieeexplore.ieee.org/document/7458115/ 736 accessed on August 17th, 2017.". 738 [IEEE-1609.4] 739 "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access 740 in Vehicular Environments (WAVE) -- Multi-Channel 741 Operation. Example URL 742 http://ieeexplore.ieee.org/document/7435228/ accessed on 743 August 17th, 2017.". 745 [IEEE-802.11-2016] 746 "IEEE Standard 802.11-2016 - IEEE Standard for Information 747 Technology - Telecommunications and information exchange 748 between systems Local and metropolitan area networks - 749 Specific requirements - Part 11: Wireless LAN Medium 750 Access Control (MAC) and Physical Layer (PHY) 751 Specifications. Status - Active Standard. Description 752 retrieved freely on September 12th, 2017, at URL 753 https://standards.ieee.org/findstds/ 754 standard/802.11-2016.html". 756 [IEEE-802.11p-2010] 757 "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information 758 Technology - Telecommunications and information exchange 759 between systems - Local and metropolitan area networks - 760 Specific requirements, Part 11: Wireless LAN Medium Access 761 Control (MAC) and Physical Layer (PHY) Specifications, 762 Amendment 6: Wireless Access in Vehicular Environments; 763 document freely available at URL 764 http://standards.ieee.org/getieee802/ 765 download/802.11p-2010.pdf retrieved on September 20th, 766 2013.". 768 Appendix A. ChangeLog 770 The changes are listed in reverse chronological order, most recent 771 changes appearing at the top of the list. 773 -33: substituted 'movement detection' for 'handover behaviour' in 774 introductory text; removed redundant phrase referring to Security 775 Considerations section; removed the phrase about forming mechanisms 776 being left out, as IP is not much concerned about L2 forming; moved 777 the Pseudonym section from main section to end of Security 778 Considerations section (and clarified 'concurrently'); capitalized 779 SHOULD consider OCB in WiFi multicast problems, and referred to more 780 recent I-D on topic; removed several phrases in a paragraph about 781 oui.txt and MAC presence in IPv6 address, as they are well known 782 info, but clarified the example of privacy risk of Company ID in MAC 783 addresses in public roads; clarified that ND MUST be used over 784 802.11-OCB. 786 -32: significantly shortened the relevant ND/OCB paragraph. It now 787 just states ND is used over OCB, w/o detailing. 789 -31: filled in the section titled "Pseudonym Handling"; removed a 790 'MAY NOT' phrase about possibility of having other prefix than the LL 791 on the link between cars; shortened and improved the paragraph about 792 Mobile IPv6, now with DNAv6; improved the ND text about ND 793 retransmissions with relationship to packet loss; changed the title 794 of an appendix from 'EPD' to 'Protocol Layering'; improved the 795 'Aspects introduced by OCB' appendix with a few phrases about the 796 channel use and references. 798 -30: a clarification on the reliability of ND over OCB and over 799 802.11. 801 -29: 803 o 805 -28: 807 o Created a new section 'Pseudonym Handling'. 809 o removed the 'Vehicle ID' appendix. 811 o improved the address generation from random MAC address. 813 o shortened Term IP-RSU definition. 815 o removed refs to two detail Clauses in IEEE documents, kept just 816 these latter. 818 -27: part 1 of addressing Human Rights review from IRTF. Removed 819 appendices F.2 and F.3. Shortened definition of IP-RSU. Removed 820 reference to 1609.4. A few other small changes, see diff. 822 -26: moved text from SLAAC section and from Design Considerations 823 appendix about privacy into a new Privacy Condiderations subsection 824 of the Security section; reformulated the SLAAC and IID sections to 825 stress only LLs can use EUI-64; removed the "GeoIP" wireshark 826 explanation; reformulated SLAAC and LL sections; added brief mention 827 of need of use LLs; clarified text about MAC address changes; dropped 828 pseudonym discussion; changed title of section describing examples of 829 packet formats. 831 -25: added a reference to 'IEEE Management Information Base', instead 832 of just 'Management Information Base'; added ref to further 833 appendices in the introductory phrases; improved text for IID 834 formation for SLAAC, inserting recommendation for RFC8064 before 835 RFC2464. 837 From draft-ietf-ipwave-ipv6-over-80211ocb-23 to draft-ietf-ipwave- 838 ipv6-over-80211ocb-24 840 o Nit: wrote "IPWAVE Working Group" on the front page, instead of 841 "Network Working Group". 843 o Addressed the comments on 6MAN: replaced a sentence about ND 844 problem with "is used over 802.11-OCB". 846 From draft-ietf-ipwave-ipv6-over-80211ocb-22 to draft-ietf-ipwave- 847 ipv6-over-80211ocb-23 849 o No content modifications, but check the entire draft chain on 850 IPv6-only: xml2rfc, submission on tools.ietf.org and datatracker. 852 From draft-ietf-ipwave-ipv6-over-80211ocb-21 to draft-ietf-ipwave- 853 ipv6-over-80211ocb-22 855 o Corrected typo, use dash in "802.11-OCB" instead of space. 857 o Improved the Frame Format section: MUST use QoSData, specify the 858 values within; clarified the Ethernet Adaptation Layer text. 860 From draft-ietf-ipwave-ipv6-over-80211ocb-20 to draft-ietf-ipwave- 861 ipv6-over-80211ocb-21 863 o Corrected a few nits and added names in Acknowledgments section. 865 o Removed unused reference to old Internet Draft tsvwg about QoS. 867 From draft-ietf-ipwave-ipv6-over-80211ocb-19 to draft-ietf-ipwave- 868 ipv6-over-80211ocb-20 870 o Reduced the definition of term "802.11-OCB". 872 o Left out of this specification which 802.11 header to use to 873 transmit IP packets in OCB mode (QoS Data header, Data header, or 874 any other). 876 o Added 'MUST' use an Ethernet Adaptation Layer, instead of 'is 877 using' an Ethernet Adaptation Layer. 879 From draft-ietf-ipwave-ipv6-over-80211ocb-18 to draft-ietf-ipwave- 880 ipv6-over-80211ocb-19 881 o Removed the text about fragmentation. 883 o Removed the mentioning of WSMP and GeoNetworking. 885 o Removed the explanation of the binary representation of the 886 EtherType. 888 o Rendered normative the paragraph about unicast and multicast 889 address mapping. 891 o Removed paragraph about addressing model, subnet structure and 892 easiness of using LLs. 894 o Clarified the Type/Subtype field in the 802.11 Header. 896 o Used RECOMMENDED instead of recommended, for the stable interface 897 identifiers. 899 From draft-ietf-ipwave-ipv6-over-80211ocb-17 to draft-ietf-ipwave- 900 ipv6-over-80211ocb-18 902 o Improved the MTU and fragmentation paragraph. 904 From draft-ietf-ipwave-ipv6-over-80211ocb-16 to draft-ietf-ipwave- 905 ipv6-over-80211ocb-17 907 o Susbtituted "MUST be increased" to "is increased" in the MTU 908 section, about fragmentation. 910 From draft-ietf-ipwave-ipv6-over-80211ocb-15 to draft-ietf-ipwave- 911 ipv6-over-80211ocb-16 913 o Removed the definition of the 'WiFi' term and its occurences. 914 Clarified a phrase that used it in Appendix C "Aspects introduced 915 by the OCB mode to 802.11". 917 o Added more normative words: MUST be 0x86DD, MUST fragment if size 918 larger than MTU, Sequence number in 802.11 Data header MUST be 919 increased. 921 From draft-ietf-ipwave-ipv6-over-80211ocb-14 to draft-ietf-ipwave- 922 ipv6-over-80211ocb-15 924 o Added normative term MUST in two places in section "Ethernet 925 Adaptation Layer". 927 From draft-ietf-ipwave-ipv6-over-80211ocb-13 to draft-ietf-ipwave- 928 ipv6-over-80211ocb-14 929 o Created a new Appendix titled "Extra Terminology" that contains 930 terms DSRC, DSRCS, OBU, RSU as defined outside IETF. Some of them 931 are used in the main Terminology section. 933 o Added two paragraphs explaining that ND and Mobile IPv6 have 934 problems working over 802.11-OCB, yet their adaptations is not 935 specified in this document. 937 From draft-ietf-ipwave-ipv6-over-80211ocb-12 to draft-ietf-ipwave- 938 ipv6-over-80211ocb-13 940 o Substituted "IP-OBU" for "OBRU", and "IP-RSU" for "RSRU" 941 throughout and improved OBU-related definitions in the Terminology 942 section. 944 From draft-ietf-ipwave-ipv6-over-80211ocb-11 to draft-ietf-ipwave- 945 ipv6-over-80211ocb-12 947 o Improved the appendix about "MAC Address Generation" by expressing 948 the technique to be an optional suggestion, not a mandatory 949 mechanism. 951 From draft-ietf-ipwave-ipv6-over-80211ocb-10 to draft-ietf-ipwave- 952 ipv6-over-80211ocb-11 954 o Shortened the paragraph on forming/terminating 802.11-OCB links. 956 o Moved the draft tsvwg-ieee-802-11 to Informative References. 958 From draft-ietf-ipwave-ipv6-over-80211ocb-09 to draft-ietf-ipwave- 959 ipv6-over-80211ocb-10 961 o Removed text requesting a new Group ID for multicast for OCB. 963 o Added a clarification of the meaning of value "3333" in the 964 section Address Mapping -- Multicast. 966 o Added note clarifying that in Europe the regional authority is not 967 ETSI, but "ECC/CEPT based on ENs from ETSI". 969 o Added note stating that the manner in which two STAtions set their 970 communication channel is not described in this document. 972 o Added a time qualifier to state that the "each node is represented 973 uniquely at a certain point in time." 975 o Removed text "This section may need to be moved" (the "Reliability 976 Requirements" section). This section stays there at this time. 978 o In the term definition "802.11-OCB" added a note stating that "any 979 implementation should comply with standards and regulations set in 980 the different countries for using that frequency band." 982 o In the RSU term definition, added a sentence explaining the 983 difference between RSU and RSRU: in terms of number of interfaces 984 and IP forwarding. 986 o Replaced "with at least two IP interfaces" with "with at least two 987 real or virtual IP interfaces". 989 o Added a term in the Terminology for "OBU". However the definition 990 is left empty, as this term is defined outside IETF. 992 o Added a clarification that it is an OBU or an OBRU in this phrase 993 "A vehicle embarking an OBU or an OBRU". 995 o Checked the entire document for a consistent use of terms OBU and 996 OBRU. 998 o Added note saying that "'p' is a letter identifying the 999 Ammendment". 1001 o Substituted lower case for capitals SHALL or MUST in the 1002 Appendices. 1004 o Added reference to RFC7042, helpful in the 3333 explanation. 1005 Removed reference to individual submission draft-petrescu-its- 1006 scenario-reqs and added reference to draft-ietf-ipwave-vehicular- 1007 networking-survey. 1009 o Added figure captions, figure numbers, and references to figure 1010 numbers instead of 'below'. Replaced "section Section" with 1011 "section" throughout. 1013 o Minor typographical errors. 1015 From draft-ietf-ipwave-ipv6-over-80211ocb-08 to draft-ietf-ipwave- 1016 ipv6-over-80211ocb-09 1018 o Significantly shortened the Address Mapping sections, by text 1019 copied from RFC2464, and rather referring to it. 1021 o Moved the EPD description to an Appendix on its own. 1023 o Shortened the Introduction and the Abstract. 1025 o Moved the tutorial section of OCB mode introduced to .11, into an 1026 appendix. 1028 o Removed the statement that suggests that for routing purposes a 1029 prefix exchange mechanism could be needed. 1031 o Removed refs to RFC3963, RFC4429 and RFC6775; these are about ND, 1032 MIP/NEMO and oDAD; they were referred in the handover discussion 1033 section, which is out. 1035 o Updated a reference from individual submission to now a WG item in 1036 IPWAVE: the survey document. 1038 o Added term definition for WiFi. 1040 o Updated the authorship and expanded the Contributors section. 1042 o Corrected typographical errors. 1044 From draft-ietf-ipwave-ipv6-over-80211ocb-07 to draft-ietf-ipwave- 1045 ipv6-over-80211ocb-08 1047 o Removed the per-channel IPv6 prohibition text. 1049 o Corrected typographical errors. 1051 From draft-ietf-ipwave-ipv6-over-80211ocb-06 to draft-ietf-ipwave- 1052 ipv6-over-80211ocb-07 1054 o Added new terms: OBRU and RSRU ('R' for Router). Refined the 1055 existing terms RSU and OBU, which are no longer used throughout 1056 the document. 1058 o Improved definition of term "802.11-OCB". 1060 o Clarified that OCB does not "strip" security, but that the 1061 operation in OCB mode is "stripped off of all .11 security". 1063 o Clarified that theoretical OCB bandwidth speed is 54mbits, but 1064 that a commonly observed bandwidth in IP-over-OCB is 12mbit/s. 1066 o Corrected typographical errors, and improved some phrasing. 1068 From draft-ietf-ipwave-ipv6-over-80211ocb-05 to draft-ietf-ipwave- 1069 ipv6-over-80211ocb-06 1071 o Updated references of 802.11-OCB document from -2012 to the IEEE 1072 802.11-2016. 1074 o In the LL address section, and in SLAAC section, added references 1075 to 7217 opaque IIDs and 8064 stable IIDs. 1077 From draft-ietf-ipwave-ipv6-over-80211ocb-04 to draft-ietf-ipwave- 1078 ipv6-over-80211ocb-05 1080 o Lengthened the title and cleanded the abstract. 1082 o Added text suggesting LLs may be easy to use on OCB, rather than 1083 GUAs based on received prefix. 1085 o Added the risks of spoofing and hijacking. 1087 o Removed the text speculation on adoption of the TSA message. 1089 o Clarified that the ND protocol is used. 1091 o Clarified what it means "No association needed". 1093 o Added some text about how two STAs discover each other. 1095 o Added mention of external (OCB) and internal network (stable), in 1096 the subnet structure section. 1098 o Added phrase explaining that both .11 Data and .11 QoS Data 1099 headers are currently being used, and may be used in the future. 1101 o Moved the packet capture example into an Appendix Implementation 1102 Status. 1104 o Suggested moving the reliability requirements appendix out into 1105 another document. 1107 o Added a IANA Consiserations section, with content, requesting for 1108 a new multicast group "all OCB interfaces". 1110 o Added new OBU term, improved the RSU term definition, removed the 1111 ETTC term, replaced more occurences of 802.11p, 802.11-OCB with 1112 802.11-OCB. 1114 o References: 1116 * Added an informational reference to ETSI's IPv6-over- 1117 GeoNetworking. 1119 * Added more references to IETF and ETSI security protocols. 1121 * Updated some references from I-D to RFC, and from old RFC to 1122 new RFC numbers. 1124 * Added reference to multicast extensions to IPsec architecture 1125 RFC. 1127 * Added a reference to 2464-bis. 1129 * Removed FCC informative references, because not used. 1131 o Updated the affiliation of one author. 1133 o Reformulation of some phrases for better readability, and 1134 correction of typographical errors. 1136 From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave- 1137 ipv6-over-80211ocb-04 1139 o Removed a few informative references pointing to Dx draft IEEE 1140 1609 documents. 1142 o Removed outdated informative references to ETSI documents. 1144 o Added citations to IEEE 1609.2, .3 and .4-2016. 1146 o Minor textual issues. 1148 From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave- 1149 ipv6-over-80211ocb-03 1151 o Keep the previous text on multiple addresses, so remove talk about 1152 MIP6, NEMOv6 and MCoA. 1154 o Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon. 1156 o Clarified the figure showing Infrastructure mode and OCB mode side 1157 by side. 1159 o Added a reference to the IP Security Architecture RFC. 1161 o Detailed the IPv6-per-channel prohibition paragraph which reflects 1162 the discussion at the last IETF IPWAVE WG meeting. 1164 o Added section "Address Mapping -- Unicast". 1166 o Added the ".11 Trailer" to pictures of 802.11 frames. 1168 o Added text about SNAP carrying the Ethertype. 1170 o New RSU definition allowing for it be both a Router and not 1171 necessarily a Router some times. 1173 o Minor textual issues. 1175 From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave- 1176 ipv6-over-80211ocb-02 1178 o Replaced almost all occurences of 802.11p with 802.11-OCB, leaving 1179 only when explanation of evolution was necessary. 1181 o Shortened by removing parameter details from a paragraph in the 1182 Introduction. 1184 o Moved a reference from Normative to Informative. 1186 o Added text in intro clarifying there is no handover spec at IEEE, 1187 and that 1609.2 does provide security services. 1189 o Named the contents the fields of the EthernetII header (including 1190 the Ethertype bitstring). 1192 o Improved relationship between two paragraphs describing the 1193 increase of the Sequence Number in 802.11 header upon IP 1194 fragmentation. 1196 o Added brief clarification of "tracking". 1198 From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave- 1199 ipv6-over-80211ocb-01 1201 o Introduced message exchange diagram illustrating differences 1202 between 802.11 and 802.11 in OCB mode. 1204 o Introduced an appendix listing for information the set of 802.11 1205 messages that may be transmitted in OCB mode. 1207 o Removed appendix sections "Privacy Requirements", "Authentication 1208 Requirements" and "Security Certificate Generation". 1210 o Removed appendix section "Non IP Communications". 1212 o Introductory phrase in the Security Considerations section. 1214 o Improved the definition of "OCB". 1216 o Introduced theoretical stacked layers about IPv6 and IEEE layers 1217 including EPD. 1219 o Removed the appendix describing the details of prohibiting IPv6 on 1220 certain channels relevant to 802.11-OCB. 1222 o Added a brief reference in the privacy text about a precise clause 1223 in IEEE 1609.3 and .4. 1225 o Clarified the definition of a Road Side Unit. 1227 o Removed the discussion about security of WSA (because is non-IP). 1229 o Removed mentioning of the GeoNetworking discussion. 1231 o Moved references to scientific articles to a separate 'overview' 1232 draft, and referred to it. 1234 Appendix B. 802.11p 1236 The term "802.11p" is an earlier definition. The behaviour of 1237 "802.11p" networks is rolled in the document IEEE Std 802.11-2016. 1238 In that document the term 802.11p disappears. Instead, each 802.11p 1239 feature is conditioned by the IEEE Management Information Base (MIB) 1240 attribute "OCBActivated" [IEEE-802.11-2016]. Whenever OCBActivated 1241 is set to true the IEEE Std 802.11-OCB state is activated. For 1242 example, an 802.11 STAtion operating outside the context of a basic 1243 service set has the OCBActivated flag set. Such a station, when it 1244 has the flag set, uses a BSS identifier equal to ff:ff:ff:ff:ff:ff. 1246 Appendix C. Aspects introduced by the OCB mode to 802.11 1248 In the IEEE 802.11-OCB mode, all nodes in the wireless range can 1249 directly communicate with each other without involving authentication 1250 or association procedures. In OCB mode, the manner in which channels 1251 are selected and used is simplified compared to when in BSS mode. 1252 Contrary to BSS mode, at link layer, it is necessary to set 1253 statically the same channel number (or frequency) on two stations 1254 that need to communicate with each other (in BSS mode this channel 1255 set operation is performed automatically during 'scanning'). The 1256 manner in which stations set their channel number in OCB mode is not 1257 specified in this document. Stations STA1 and STA2 can exchange IP 1258 packets only if they are set on the same channel. At IP layer, they 1259 then discover each other by using the IPv6 Neighbor Discovery 1260 protocol. The allocation of a particular channel for a particular 1261 use is defined statically in standards authored by ETSI (in Europe), 1262 FCC in America, and similar organisations in South Korea, Japan and 1263 other parts of the world. 1265 Briefly, the IEEE 802.11-OCB mode has the following properties: 1267 o The use by each node of a 'wildcard' BSSID (i.e., each bit of the 1268 BSSID is set to 1) 1270 o No IEEE 802.11 Beacon frames are transmitted 1272 o No authentication is required in order to be able to communicate 1274 o No association is needed in order to be able to communicate 1276 o No encryption is provided in order to be able to communicate 1278 o Flag dot11OCBActivated is set to true 1280 All the nodes in the radio communication range (IP-OBU and IP-RSU) 1281 receive all the messages transmitted (IP-OBU and IP-RSU) within the 1282 radio communications range. The eventual conflict(s) are resolved by 1283 the MAC CDMA function. 1285 The message exchange diagram in Figure 3 illustrates a comparison 1286 between traditional 802.11 and 802.11 in OCB mode. The 'Data' 1287 messages can be IP packets such as HTTP or others. Other 802.11 1288 management and control frames (non IP) may be transmitted, as 1289 specified in the 802.11 standard. For information, the names of 1290 these messages as currently specified by the 802.11 standard are 1291 listed in Appendix G. 1293 STA AP STA1 STA2 1294 | | | | 1295 |<------ Beacon -------| |<------ Data -------->| 1296 | | | | 1297 |---- Probe Req. ----->| |<------ Data -------->| 1298 |<--- Probe Res. ------| | | 1299 | | |<------ Data -------->| 1300 |---- Auth Req. ------>| | | 1301 |<--- Auth Res. -------| |<------ Data -------->| 1302 | | | | 1303 |---- Asso Req. ------>| |<------ Data -------->| 1304 |<--- Asso Res. -------| | | 1305 | | |<------ Data -------->| 1306 |<------ Data -------->| | | 1307 |<------ Data -------->| |<------ Data -------->| 1309 (i) 802.11 Infrastructure mode (ii) 802.11-OCB mode 1311 Figure 3: Difference between messages exchanged on 802.11 (left) and 1312 802.11-OCB (right) 1314 The interface 802.11-OCB was specified in IEEE Std 802.11p (TM) -2010 1315 [IEEE-802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, 1316 titled "Amendment 6: Wireless Access in Vehicular Environments". 1317 Since then, this amendment has been integrated in IEEE 802.11(TM) 1318 -2012 and -2016 [IEEE-802.11-2016]. 1320 In document 802.11-2016, anything qualified specifically as 1321 "OCBActivated", or "outside the context of a basic service" set to be 1322 true, then it is actually referring to OCB aspects introduced to 1323 802.11. 1325 In order to delineate the aspects introduced by 802.11-OCB to 802.11, 1326 we refer to the earlier [IEEE-802.11p-2010]. The amendment is 1327 concerned with vehicular communications, where the wireless link is 1328 similar to that of Wireless LAN (using a PHY layer specified by 1329 802.11a/b/g/n), but which needs to cope with the high mobility factor 1330 inherent in scenarios of communications between moving vehicles, and 1331 between vehicles and fixed infrastructure deployed along roads. 1332 While 'p' is a letter identifying the Ammendment, just like 'a, b, g' 1333 and 'n' are, 'p' is concerned more with MAC modifications, and a 1334 little with PHY modifications; the others are mainly about PHY 1335 modifications. It is possible in practice to combine a 'p' MAC with 1336 an 'a' PHY by operating outside the context of a BSS with OFDM at 1337 5.4GHz and 5.9GHz. 1339 The 802.11-OCB links are specified to be compatible as much as 1340 possible with the behaviour of 802.11a/b/g/n and future generation 1341 IEEE WLAN links. From the IP perspective, an 802.11-OCB MAC layer 1342 offers practically the same interface to IP as the 802.11a/b/g/n and 1343 802.3. A packet sent by an IP-OBU may be received by one or multiple 1344 IP-RSUs. The link-layer resolution is performed by using the IPv6 1345 Neighbor Discovery protocol. 1347 To support this similarity statement (IPv6 is layered on top of LLC 1348 on top of 802.11-OCB, in the same way that IPv6 is layered on top of 1349 LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on 1350 top of 802.3 (for Ethernet)) it is useful to analyze the differences 1351 between 802.11-OCB and 802.11 specifications. During this analysis, 1352 we note that whereas 802.11-OCB lists relatively complex and numerous 1353 changes to the MAC layer (and very little to the PHY layer), there 1354 are only a few characteristics which may be important for an 1355 implementation transmitting IPv6 packets on 802.11-OCB links. 1357 The most important 802.11-OCB point which influences the IPv6 1358 functioning is the OCB characteristic; an additional, less direct 1359 influence, is the maximum bandwidth afforded by the PHY modulation/ 1360 demodulation methods and channel access specified by 802.11-OCB. The 1361 maximum bandwidth theoretically possible in 802.11-OCB is 54 Mbit/s 1362 (when using, for example, the following parameters: 20 MHz channel; 1363 modulation 64-QAM; coding rate R is 3/4); in practice of IP-over- 1364 802.11-OCB a commonly observed figure is 12Mbit/s; this bandwidth 1365 allows the operation of a wide range of protocols relying on IPv6. 1367 o Operation Outside the Context of a BSS (OCB): the (earlier 1368 802.11p) 802.11-OCB links are operated without a Basic Service Set 1369 (BSS). This means that the frames IEEE 802.11 Beacon, Association 1370 Request/Response, Authentication Request/Response, and similar, 1371 are not used. The used identifier of BSS (BSSID) has a 1372 hexadecimal value always 0xffffffffffff (48 '1' bits, represented 1373 as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' 1374 BSSID), as opposed to an arbitrary BSSID value set by 1375 administrator (e.g. 'My-Home-AccessPoint'). The OCB operation - 1376 namely the lack of beacon-based scanning and lack of 1377 authentication - should be taken into account when the Mobile IPv6 1378 protocol [RFC6275] and the protocols for IP layer security 1379 [RFC4301] are used. The way these protocols adapt to OCB is not 1380 described in this document. 1382 o Timing Advertisement: is a new message defined in 802.11-OCB, 1383 which does not exist in 802.11a/b/g/n. This message is used by 1384 stations to inform other stations about the value of time. It is 1385 similar to the time as delivered by a GNSS system (Galileo, GPS, 1386 ...) or by a cellular system. This message is optional for 1387 implementation. 1389 o Frequency range: this is a characteristic of the PHY layer, with 1390 almost no impact on the interface between MAC and IP. However, it 1391 is worth considering that the frequency range is regulated by a 1392 regional authority (ARCEP, ECC/CEPT based on ENs from ETSI, FCC, 1393 etc.); as part of the regulation process, specific applications 1394 are associated with specific frequency ranges. In the case of 1395 802.11-OCB, the regulator associates a set of frequency ranges, or 1396 slots within a band, to the use of applications of vehicular 1397 communications, in a band known as "5.9GHz". The 5.9GHz band is 1398 different from the 2.4GHz and 5GHz bands used by Wireless LAN. 1399 However, as with Wireless LAN, the operation of 802.11-OCB in 1400 "5.9GHz" bands is exempt from owning a license in EU (in US the 1401 5.9GHz is a licensed band of spectrum; for the fixed 1402 infrastructure an explicit FCC authorization is required; for an 1403 on-board device a 'licensed-by-rule' concept applies: rule 1404 certification conformity is required.) Technical conditions are 1405 different than those of the bands "2.4GHz" or "5GHz". The allowed 1406 power levels, and implicitly the maximum allowed distance between 1407 vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20 1408 dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum 1409 distance of approximately 1km, compared to approximately 50m. 1411 Additionally, specific conditions related to congestion avoidance, 1412 jamming avoidance, and radar detection are imposed on the use of 1413 DSRC (in US) and on the use of frequencies for Intelligent 1414 Transportation Systems (in EU), compared to Wireless LAN 1415 (802.11a/b/g/n). 1417 o 'Half-rate' encoding: as the frequency range, this parameter is 1418 related to PHY, and thus has not much impact on the interface 1419 between the IP layer and the MAC layer. 1421 o In vehicular communications using 802.11-OCB links, there are 1422 strong privacy requirements with respect to addressing. While the 1423 802.11-OCB standard does not specify anything in particular with 1424 respect to MAC addresses, in these settings there exists a strong 1425 need for dynamic change of these addresses (as opposed to the non- 1426 vehicular settings - real wall protection - where fixed MAC 1427 addresses do not currently pose some privacy risks). This is 1428 further described in Section 5. A relevant function is described 1429 in documents IEEE 1609.3-2016 [IEEE-1609.3] and IEEE 1609.4-2016 1430 [IEEE-1609.4]. 1432 Appendix D. Changes Needed on a software driver 802.11a to become a 1433 802.11-OCB driver 1435 The 802.11p amendment modifies both the 802.11 stack's physical and 1436 MAC layers but all the induced modifications can be quite easily 1437 obtained by modifying an existing 802.11a ad-hoc stack. 1439 Conditions for a 802.11a hardware to be 802.11-OCB compliant: 1441 o The PHY entity shall be an orthogonal frequency division 1442 multiplexing (OFDM) system. It must support the frequency bands 1443 on which the regulator recommends the use of ITS communications, 1444 for example using IEEE 802.11-OCB layer, in France: 5875MHz to 1445 5925MHz. 1447 o The OFDM system must provide a "half-clocked" operation using 10 1448 MHz channel spacings. 1450 o The chip transmit spectrum mask must be compliant to the "Transmit 1451 spectrum mask" from the IEEE 802.11p amendment (but experimental 1452 environments tolerate otherwise). 1454 o The chip should be able to transmit up to 44.8 dBm when used by 1455 the US government in the United States, and up to 33 dBm in 1456 Europe; other regional conditions apply. 1458 Changes needed on the network stack in OCB mode: 1460 o Physical layer: 1462 * The chip must use the Orthogonal Frequency Multiple Access 1463 (OFDM) encoding mode. 1465 * The chip must be set in half-mode rate mode (the internal clock 1466 frequency is divided by two). 1468 * The chip must use dedicated channels and should allow the use 1469 of higher emission powers. This may require modifications to 1470 the local computer file that describes regulatory domains 1471 rules, if used by the kernel to enforce local specific 1472 restrictions. Such modifications to the local computer file 1473 must respect the location-specific regulatory rules. 1475 MAC layer: 1477 * All management frames (beacons, join, leave, and others) 1478 emission and reception must be disabled except for frames of 1479 subtype Action and Timing Advertisement (defined below). 1481 * No encryption key or method must be used. 1483 * Packet emission and reception must be performed as in ad-hoc 1484 mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff). 1486 * The functions related to joining a BSS (Association Request/ 1487 Response) and for authentication (Authentication Request/Reply, 1488 Challenge) are not called. 1490 * The beacon interval is always set to 0 (zero). 1492 * Timing Advertisement frames, defined in the amendment, should 1493 be supported. The upper layer should be able to trigger such 1494 frames emission and to retrieve information contained in 1495 received Timing Advertisements. 1497 Appendix E. Protocol Layering 1499 A more theoretical and detailed view of layer stacking, and 1500 interfaces between the IP layer and 802.11-OCB layers, is illustrated 1501 in Figure 4. The IP layer operates on top of the EtherType Protocol 1502 Discrimination (EPD); this Discrimination layer is described in IEEE 1503 Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP 1504 (Link Layer Control Service Access Point). 1506 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1507 | IPv6 | 1508 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ 1509 { LLC_SAP } 802.11-OCB 1510 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary 1511 | EPD | | | 1512 | | MLME | | 1513 +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | 1514 | MAC Sublayer | | | 802.11-OCB 1515 | and ch. coord. | | SME | Services 1516 +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | 1517 | | PLME | | 1518 | PHY Layer | PLME_SAP | 1519 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1521 Figure 4: EtherType Protocol Discrimination 1523 Appendix F. Design Considerations 1525 The networks defined by 802.11-OCB are in many ways similar to other 1526 networks of the 802.11 family. In theory, the encapsulation of IPv6 1527 over 802.11-OCB could be very similar to the operation of IPv6 over 1528 other networks of the 802.11 family. However, the high mobility, 1529 strong link asymmetry and very short connection makes the 802.11-OCB 1530 link significantly different from other 802.11 networks. Also, the 1531 automotive applications have specific requirements for reliability, 1532 security and privacy, which further add to the particularity of the 1533 802.11-OCB link. 1535 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode 1537 For information, at the time of writing, this is the list of IEEE 1538 802.11 messages that may be transmitted in OCB mode, i.e. when 1539 dot11OCBActivated is true in a STA: 1541 o The STA may send management frames of subtype Action and, if the 1542 STA maintains a TSF Timer, subtype Timing Advertisement; 1544 o The STA may send control frames, except those of subtype PS-Poll, 1545 CF-End, and CF-End plus CFAck; 1547 o The STA may send data frames of subtype Data, Null, QoS Data, and 1548 QoS Null. 1550 Appendix H. Examples of Packet Formats 1552 This section describes an example of an IPv6 Packet captured over a 1553 IEEE 802.11-OCB link. 1555 By way of example we show that there is no modification in the 1556 headers when transmitted over 802.11-OCB networks - they are 1557 transmitted like any other 802.11 and Ethernet packets. 1559 We describe an experiment of capturing an IPv6 packet on an 1560 802.11-OCB link. In topology depicted in Figure 5, the packet is an 1561 IPv6 Router Advertisement. This packet is emitted by a Router on its 1562 802.11-OCB interface. The packet is captured on the Host, using a 1563 network protocol analyzer (e.g. Wireshark); the capture is performed 1564 in two different modes: direct mode and 'monitor' mode. The topology 1565 used during the capture is depicted below. 1567 The packet is captured on the Host. The Host is an IP-OBU containing 1568 an 802.11 interface in format PCI express (an ITRI product). The 1569 kernel runs the ath5k software driver with modifications for OCB 1570 mode. The capture tool is Wireshark. The file format for save and 1571 analyze is 'pcap'. The packet is generated by the Router. The 1572 Router is an IP-RSU (ITRI product). 1574 +--------+ +-------+ 1575 | | 802.11-OCB Link | | 1576 ---| Router |--------------------------------| Host | 1577 | | | | 1578 +--------+ +-------+ 1580 Figure 5: Topology for capturing IP packets on 802.11-OCB 1582 During several capture operations running from a few moments to 1583 several hours, no message relevant to the BSSID contexts were 1584 captured (no Association Request/Response, Authentication Req/Resp, 1585 Beacon). This shows that the operation of 802.11-OCB is outside the 1586 context of a BSSID. 1588 Overall, the captured message is identical with a capture of an IPv6 1589 packet emitted on a 802.11b interface. The contents are precisely 1590 similar. 1592 H.1. Capture in Monitor Mode 1594 The IPv6 RA packet captured in monitor mode is illustrated below. 1595 The radio tap header provides more flexibility for reporting the 1596 characteristics of frames. The Radiotap Header is prepended by this 1597 particular stack and operating system on the Host machine to the RA 1598 packet received from the network (the Radiotap Header is not present 1599 on the air). The implementation-dependent Radiotap Header is useful 1600 for piggybacking PHY information from the chip's registers as data in 1601 a packet understandable by userland applications using Socket 1602 interfaces (the PHY interface can be, for example: power levels, data 1603 rate, ratio of signal to noise). 1605 The packet present on the air is formed by IEEE 802.11 Data Header, 1606 Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. 1608 Radiotap Header v0 1609 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1610 |Header Revision| Header Pad | Header length | 1611 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1612 | Present flags | 1613 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1614 | Data Rate | Pad | 1615 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1617 IEEE 802.11 Data Header 1618 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1619 | Type/Subtype and Frame Ctrl | Duration | 1620 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1621 | Receiver Address... 1622 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1623 ... Receiver Address | Transmitter Address... 1624 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1625 ... Transmitter Address | 1626 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1627 | BSS Id... 1628 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1629 ... BSS Id | Frag Number and Seq Number | 1630 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1632 Logical-Link Control Header 1633 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1634 | DSAP |I| SSAP |C| Control field | Org. code... 1635 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1636 ... Organizational Code | Type | 1637 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1638 IPv6 Base Header 1639 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1640 |Version| Traffic Class | Flow Label | 1641 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1642 | Payload Length | Next Header | Hop Limit | 1643 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1644 | | 1645 + + 1646 | | 1647 + Source Address + 1648 | | 1649 + + 1650 | | 1651 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1652 | | 1653 + + 1654 | | 1655 + Destination Address + 1656 | | 1657 + + 1658 | | 1659 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1661 Router Advertisement 1662 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1663 | Type | Code | Checksum | 1664 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1665 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1666 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1667 | Reachable Time | 1668 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1669 | Retrans Timer | 1670 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1671 | Options ... 1672 +-+-+-+-+-+-+-+-+-+-+-+- 1674 The value of the Data Rate field in the Radiotap header is set to 6 1675 Mb/s. This indicates the rate at which this RA was received. 1677 The value of the Transmitter address in the IEEE 802.11 Data Header 1678 is set to a 48bit value. The value of the destination address is 1679 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS 1680 Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network 1681 protocol analyzer as being "broadcast". The Fragment number and 1682 sequence number fields are together set to 0x90C6. 1684 The value of the Organization Code field in the Logical-Link Control 1685 Header is set to 0x0, recognized as "Encapsulated Ethernet". The 1686 value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise 1687 #86DD), recognized as "IPv6". 1689 A Router Advertisement is periodically sent by the router to 1690 multicast group address ff02::1. It is an icmp packet type 134. The 1691 IPv6 Neighbor Discovery's Router Advertisement message contains an 1692 8-bit field reserved for single-bit flags, as described in [RFC4861]. 1694 The IPv6 header contains the link local address of the router 1695 (source) configured via EUI-64 algorithm, and destination address set 1696 to ff02::1. 1698 The Ethernet Type field in the logical-link control header is set to 1699 0x86dd which indicates that the frame transports an IPv6 packet. In 1700 the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 1701 which is the corresponding multicast MAC address. The BSS id is a 1702 broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link 1703 duration between vehicles and the roadside infrastructure, there is 1704 no need in IEEE 802.11-OCB to wait for the completion of association 1705 and authentication procedures before exchanging data. IEEE 1706 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) 1707 and may start communicating as soon as they arrive on the 1708 communication channel. 1710 H.2. Capture in Normal Mode 1712 The same IPv6 Router Advertisement packet described above (monitor 1713 mode) is captured on the Host, in the Normal mode, and depicted 1714 below. 1716 Ethernet II Header 1717 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1718 | Destination... 1719 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1720 ...Destination | Source... 1721 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1722 ...Source | 1723 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1724 | Type | 1725 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1727 IPv6 Base Header 1728 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1729 |Version| Traffic Class | Flow Label | 1730 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1731 | Payload Length | Next Header | Hop Limit | 1732 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1733 | | 1734 + + 1735 | | 1736 + Source Address + 1737 | | 1738 + + 1739 | | 1740 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1741 | | 1742 + + 1743 | | 1744 + Destination Address + 1745 | | 1746 + + 1747 | | 1748 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1750 Router Advertisement 1751 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1752 | Type | Code | Checksum | 1753 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1754 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1755 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1756 | Reachable Time | 1757 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1758 | Retrans Timer | 1759 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1760 | Options ... 1761 +-+-+-+-+-+-+-+-+-+-+-+- 1763 One notices that the Radiotap Header, the IEEE 802.11 Data Header and 1764 the Logical-Link Control Headers are not present. On the other hand, 1765 a new header named Ethernet II Header is present. 1767 The Destination and Source addresses in the Ethernet II header 1768 contain the same values as the fields Receiver Address and 1769 Transmitter Address present in the IEEE 802.11 Data Header in the 1770 "monitor" mode capture. 1772 The value of the Type field in the Ethernet II header is 0x86DD 1773 (recognized as "IPv6"); this value is the same value as the value of 1774 the field Type in the Logical-Link Control Header in the "monitor" 1775 mode capture. 1777 The knowledgeable experimenter will no doubt notice the similarity of 1778 this Ethernet II Header with a capture in normal mode on a pure 1779 Ethernet cable interface. 1781 An Adaptation layer is inserted on top of a pure IEEE 802.11 MAC 1782 layer, in order to adapt packets, before delivering the payload data 1783 to the applications. It adapts 802.11 LLC/MAC headers to Ethernet II 1784 headers. In further detail, this adaptation consists in the 1785 elimination of the Radiotap, 802.11 and LLC headers, and in the 1786 insertion of the Ethernet II header. In this way, IPv6 runs straight 1787 over LLC over the 802.11-OCB MAC layer; this is further confirmed by 1788 the use of the unique Type 0x86DD. 1790 Appendix I. Extra Terminology 1792 The following terms are defined outside the IETF. They are used to 1793 define the main terms in the main terminology section Section 2. 1795 DSRC (Dedicated Short Range Communication): a term defined outside 1796 the IETF. The US Federal Communications Commission (FCC) Dedicated 1797 Short Range Communication (DSRC) is defined in the Code of Federal 1798 Regulations (CFR) 47, Parts 90 and 95. This Code is referred in the 1799 definitions below. At the time of the writing of this Internet 1800 Draft, the last update of this Code was dated October 1st, 2010. 1802 DSRCS (Dedicated Short-Range Communications Services): a term defined 1803 outside the IETF. The use of radio techniques to transfer data over 1804 short distances between roadside and mobile units, between mobile 1805 units, and between portable and mobile units to perform operations 1806 related to the improvement of traffic flow, traffic safety, and other 1807 intelligent transportation service applications in a variety of 1808 environments. DSRCS systems may also transmit status and 1809 instructional messages related to the units involve. [Ref. 47 CFR 1810 90.7 - Definitions] 1811 OBU (On-Board Unit): a term defined outside the IETF. An On-Board 1812 Unit is a DSRCS transceiver that is normally mounted in or on a 1813 vehicle, or which in some instances may be a portable unit. An OBU 1814 can be operational while a vehicle or person is either mobile or 1815 stationary. The OBUs receive and contend for time to transmit on one 1816 or more radio frequency (RF) channels. Except where specifically 1817 excluded, OBU operation is permitted wherever vehicle operation or 1818 human passage is permitted. The OBUs mounted in vehicles are 1819 licensed by rule under part 95 of the respective chapter and 1820 communicate with Roadside Units (RSUs) and other OBUs. Portable OBUs 1821 are also licensed by rule under part 95 of the respective chapter. 1822 OBU operations in the Unlicensed National Information Infrastructure 1823 (UNII) Bands follow the rules in those bands. - [CFR 90.7 - 1824 Definitions]. 1826 RSU (Road-Side Unit): a term defined outside of IETF. A Roadside 1827 Unit is a DSRC transceiver that is mounted along a road or pedestrian 1828 passageway. An RSU may also be mounted on a vehicle or is hand 1829 carried, but it may only operate when the vehicle or hand- carried 1830 unit is stationary. Furthermore, an RSU operating under the 1831 respectgive part is restricted to the location where it is licensed 1832 to operate. However, portable or hand-held RSUs are permitted to 1833 operate where they do not interfere with a site-licensed operation. 1834 A RSU broadcasts data to OBUs or exchanges data with OBUs in its 1835 communications zone. An RSU also provides channel assignments and 1836 operating instructions to OBUs in its communications zone, when 1837 required. - [CFR 90.7 - Definitions]. 1839 Authors' Addresses 1841 Alexandre Petrescu 1842 CEA, LIST 1843 CEA Saclay 1844 Gif-sur-Yvette , Ile-de-France 91190 1845 France 1847 Phone: +33169089223 1848 Email: Alexandre.Petrescu@cea.fr 1850 Nabil Benamar 1851 Moulay Ismail University 1852 Morocco 1854 Phone: +212670832236 1855 Email: n.benamar@est.umi.ac.ma 1856 Jerome Haerri 1857 Eurecom 1858 Sophia-Antipolis 06904 1859 France 1861 Phone: +33493008134 1862 Email: Jerome.Haerri@eurecom.fr 1864 Jong-Hyouk Lee 1865 Sangmyung University 1866 31, Sangmyeongdae-gil, Dongnam-gu 1867 Cheonan 31066 1868 Republic of Korea 1870 Email: jonghyouk@smu.ac.kr 1872 Thierry Ernst 1873 YoGoKo 1874 France 1876 Email: thierry.ernst@yogoko.fr