idnits 2.17.1 draft-ietf-ipwave-ipv6-over-80211ocb-34.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 18, 2018) is 1956 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reference: RFC 7042 (Obsoleted by RFC 9542) ** Downref: Normative reference to an Informational RFC: RFC 7721 == Outdated reference: A later version (-15) exists of draft-ietf-mboned-ieee802-mcast-problems-04 Summary: 5 errors (**), 0 flaws (~~), 3 warnings (==), 2 comments (--).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 21, 2019 Moulay Ismail University 6 J. Haerri 7 Eurecom 8 J. Lee 9 Sangmyung University 10 T. Ernst 11 YoGoKo 12 December 18, 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-34 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 21, 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 . . . . . . . . . 10 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.ietf-mboned-ieee802-mcast-problems]. These issues may be 308 exacerbated in OCB mode. Solutions for these problems SHOULD 309 consider the OCB mode of operation. 311 4.5. Stateless Autoconfiguration 313 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 314 MAY be assigned to an 802.11-OCB interface. This section describes 315 the formation of Interface Identifiers for IPv6 addresses of type 316 'Global' or 'Unique Local'. For Interface Identifiers for IPv6 317 address of type 'Link-Local' see Section 4.3. 319 The Interface Identifier for an 802.11-OCB interface is formed using 320 the same rules as the Interface Identifier for an Ethernet interface; 321 the RECOMMENDED method for forming stable Interface Identifiers 322 (IIDs) is described in [RFC8064]. The method of forming IIDs 323 described in section 4 of [RFC2464] MAY be used during transition 324 time. 326 The bits in the Interface Identifier have no generic meaning and the 327 identifier should be treated as an opaque value. The bits 328 'Universal' and 'Group' in the identifier of an 802.11-OCB interface 329 are significant, as this is an IEEE link-layer address. The details 330 of this significance are described in [RFC7136]. If semantically 331 opaque Interface Identifiers are needed, a potential method for 332 generating semantically opaque Interface Identifiers with IPv6 333 Stateless Address Autoconfiguration is given in [RFC7217]. 335 Semantically opaque Interface Identifiers, instead of meaningful 336 Interface Identifiers derived from a valid and meaningful MAC address 337 ([RFC2464], section 4), MAY be needed in order to avoid certain 338 privacy risks. 340 The IPv6 packets can be captured easily in the Internet and on-link 341 in public roads. For this reason, an attacker may realize many 342 attacks on privacy. One such attack on 802.11-OCB is to capture, 343 store and correlate Company ID information present in MAC addresses 344 of many cars (e.g. listen for Router Advertisements, or other IPv6 345 application data packets, and record the value of the source address 346 in these packets). Further correlation of this information with 347 other data captured by other means, or other visual information (car 348 color, others) MAY constitute privacy risks. 350 In order to avoid these risks, opaque Interface Identifiers MAY be 351 formed according to rules described in [RFC7217]. These opaque 352 Interface Identifiers are formed starting from identifiers different 353 than the MAC addresses, and from cryptographically strong material. 354 Thus, privacy sensitive information is absent from Interface IDs, and 355 it is impossible to calculate the initial value from which the 356 Interface ID was calculated. 358 Some applications that use IPv6 packets on 802.11-OCB links (among 359 other link types) may benefit from IPv6 addresses whose Interface 360 Identifiers don't change too often. It is RECOMMENDED to use the 361 mechanisms described in RFC 7217 to permit the use of Stable 362 Interface Identifiers that do not change within one subnet prefix. A 363 possible source for the Net-Iface Parameter is a virtual interface 364 name, or logical interface name, that is decided by a local 365 administrator. 367 The way Interface Identifiers are used MAY involve risks to privacy, 368 as described in Section 5.1. 370 4.6. Subnet Structure 372 A subnet is formed by the external 802.11-OCB interfaces of vehicles 373 that are in close range (not by their in-vehicle interfaces). This 374 subnet MUST use at least the link-local prefix fe80::/10 and the 375 interfaces MUST be assigned IPv6 addresses of type link-local. 377 The structure of this subnet is ephemeral, in that it is strongly 378 influenced by the mobility of vehicles: the 802.11 hidden node 379 effects appear; the 802.11 networks in OCB mode may be considered as 380 'ad-hoc' networks with an addressing model as described in [RFC5889]. 381 On another hand, the structure of the internal subnets in each car is 382 relatively stable. 384 As recommended in [RFC5889], when the timing requirements are very 385 strict (e.g. fast drive through IP-RSU coverage), no on-link subnet 386 prefix should be configured on an 802.11-OCB interface. In such 387 cases, the exclusive use of IPv6 link-local addresses is RECOMMENDED. 389 Additionally, even if the timing requirements are not very strict 390 (e.g. the moving subnet formed by two following vehicles is stable, a 391 fixed IP-RSU is absent), the subnet is disconnected from the Internet 392 (a default route is absent), and the addressing peers are equally 393 qualified (impossible to determine that some vehicle owns and 394 distributes addresses to others) the use of link-local addresses is 395 RECOMMENDED. 397 The Neighbor Discovery protocol (ND) [RFC4861] MUST be used over 398 802.11-OCB links. 400 Protocols like Mobile IPv6 [RFC6275] and DNAv6 [RFC6059], which 401 depend on timely movement detection, might need additional tuning 402 work to handle the lack of link-layer notifications during handover. 403 This is for further study. 405 5. Security Considerations 407 Any security mechanism at the IP layer or above that may be carried 408 out for the general case of IPv6 may also be carried out for IPv6 409 operating over 802.11-OCB. 411 The OCB operation is stripped off of all existing 802.11 link-layer 412 security mechanisms. There is no encryption applied below the 413 network layer running on 802.11-OCB. At application layer, the IEEE 414 1609.2 document [IEEE-1609.2] does provide security services for 415 certain applications to use; application-layer mechanisms are out-of- 416 scope of this document. On another hand, a security mechanism 417 provided at networking layer, such as IPsec [RFC4301], may provide 418 data security protection to a wider range of applications. 420 802.11-OCB does not provide any cryptographic protection, because it 421 operates outside the context of a BSS (no Association Request/ 422 Response, no Challenge messages). Any attacker can therefore just 423 sit in the near range of vehicles, sniff the network (just set the 424 interface card's frequency to the proper range) and perform attacks 425 without needing to physically break any wall. Such a link is less 426 protected than commonly used links (wired link or protected 802.11). 428 The potential attack vectors are: MAC address spoofing, IP address 429 and session hijacking, and privacy violation Section 5.1. 431 Within the IPsec Security Architecture [RFC4301], the IPsec AH and 432 ESP headers [RFC4302] and [RFC4303] respectively, its multicast 433 extensions [RFC5374], HTTPS [RFC2818] and SeND [RFC3971] protocols 434 can be used to protect communications. Further, the assistance of 435 proper Public Key Infrastructure (PKI) protocols [RFC4210] is 436 necessary to establish credentials. More IETF protocols are 437 available in the toolbox of the IP security protocol designer. 438 Certain ETSI protocols related to security protocols in Intelligent 439 Transportation Systems are described in [ETSI-sec-archi]. 441 5.1. Privacy Considerations 443 As with all Ethernet and 802.11 interface identifiers ([RFC7721]), 444 the identifier of an 802.11-OCB interface may involve privacy, MAC 445 address spoofing and IP address hijacking risks. A vehicle embarking 446 an IP-OBU whose egress interface is 802.11-OCB may expose itself to 447 eavesdropping and subsequent correlation of data; this may reveal 448 data considered private by the vehicle owner; there is a risk of 449 being tracked. In outdoors public environments, where vehicles 450 typically circulate, the privacy risks are more important than in 451 indoors settings. It is highly likely that attacker sniffers are 452 deployed along routes which listen for IEEE frames, including IP 453 packets, of vehicles passing by. For this reason, in the 802.11-OCB 454 deployments, there is a strong necessity to use protection tools such 455 as dynamically changing MAC addresses Section 5.2, semantically 456 opaque Interface Identifiers and stable Interface Identifiers 457 Section 4.5. This may help mitigate privacy risks to a certain 458 level. 460 5.2. MAC Address and Interface ID Generation 462 In 802.11-OCB networks, the MAC addresses MAY change during well 463 defined renumbering events. In the moment the MAC address is changed 464 on an 802.11-OCB interface all the Interface Identifiers of IPv6 465 addresses assigned to that interface MUST change. 467 The policy dictating when the MAC address is changed on the 468 802.11-OCB interface is to-be-determined. For more information on 469 the motivation of this policy please refer to the privacy discussion 470 in Appendix C. 472 A 'randomized' MAC address has the following characteristics: 474 o Bit "Local/Global" set to "locally admninistered". 476 o Bit "Unicast/Multicast" set to "Unicast". 478 o The 46 remaining bits are set to a random value, using a random 479 number generator that meets the requirements of [RFC4086]. 481 To meet the randomization requirements for the 46 remaining bits, a 482 hash function may be used. For example, the SHA256 hash function may 483 be used with input a 256 bit local secret, the 'nominal' MAC Address 484 of the interface, and a representation of the date and time of the 485 renumbering event. 487 A randomized Interface ID has the same characteristics of a 488 randomized MAC address, except the length in bits. A MAC address 489 SHOULD be of length 48 decimal. An Interface ID SHOULD be of length 490 64 decimal for all types of IPv6 addresses. In the particular case 491 of IPv6 link-local addresses, the length of the Interface ID MAY be 492 118 decimal. 494 5.3. Pseudonym Handling 496 The demand for privacy protection of vehicles' and drivers' 497 identities, which could be granted by using a pseudonym or alias 498 identity at the same time, may hamper the required confidentiality of 499 messages and trust between participants - especially in safety 500 critical vehicular communication. 502 o Particular challenges arise when the pseudonymization mechanism 503 used relies on (randomized) re-addressing. 505 o A proper pseudonymization tool operated by a trusted third party 506 may be needed to ensure both aspects simultaneously (privacy 507 protection on one hand and trust between participants on another 508 hand). 510 o This is discussed in Section 4.5 and Section 5 of this document. 512 o Pseudonymity is also discussed in 513 [I-D.ietf-ipwave-vehicular-networking-survey] in its sections 514 4.2.4 and 5.1.2. 516 6. IANA Considerations 518 No request to IANA. 520 7. Contributors 522 Christian Huitema, Tony Li. 524 Romain Kuntz contributed extensively about IPv6 handovers between 525 links running outside the context of a BSS (802.11-OCB links). 527 Tim Leinmueller contributed the idea of the use of IPv6 over 528 802.11-OCB for distribution of certificates. 530 Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey 531 Voronov provided significant feedback on the experience of using IP 532 messages over 802.11-OCB in initial trials. 534 Michelle Wetterwald contributed extensively the MTU discussion, 535 offered the ETSI ITS perspective, and reviewed other parts of the 536 document. 538 8. Acknowledgements 540 The authors would like to thank Witold Klaudel, Ryuji Wakikawa, 541 Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan 542 Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray 543 Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, 544 Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne, 545 Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark, 546 Bob Moskowitz, Andrew Dryden, Georg Mayer, Dorothy Stanley, Sandra 547 Cespedes, Mariano Falcitelli, Sri Gundavelli, Abdussalam Baryun, 548 Margaret Cullen, Erik Kline, Carlos Jesus Bernardos Cano, Ronald in 549 't Velt, Katrin Sjoberg, Roland Bless, Tijink Jasja, Kevin Smith, 550 Brian Carpenter, Julian Reschke, Mikael Abrahamsson, Dirk von Hugo, 551 Lorenzo Colitti and William Whyte. Their valuable comments clarified 552 particular issues and generally helped to improve the document. 554 Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB 555 drivers for linux and described how. 557 For the multicast discussion, the authors would like to thank Owen 558 DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and 559 participants to discussions in network working groups. 561 The authors would like to thank participants to the Birds-of- 562 a-Feather "Intelligent Transportation Systems" meetings held at IETF 563 in 2016. 565 Human Rights Protocol Considerations review by Amelia Andersdotter. 567 9. References 569 9.1. Normative References 571 [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission 572 of IP datagrams over IEEE 802 networks", STD 43, RFC 1042, 573 DOI 10.17487/RFC1042, February 1988, 574 . 576 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 577 Requirement Levels", BCP 14, RFC 2119, 578 DOI 10.17487/RFC2119, March 1997, 579 . 581 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 582 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 583 . 585 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 586 DOI 10.17487/RFC2818, May 2000, 587 . 589 [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related 590 Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, 591 . 593 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 594 "SEcure Neighbor Discovery (SEND)", RFC 3971, 595 DOI 10.17487/RFC3971, March 2005, 596 . 598 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 599 "Randomness Requirements for Security", BCP 106, RFC 4086, 600 DOI 10.17487/RFC4086, June 2005, 601 . 603 [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast 604 Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005, 605 . 607 [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, 608 "Internet X.509 Public Key Infrastructure Certificate 609 Management Protocol (CMP)", RFC 4210, 610 DOI 10.17487/RFC4210, September 2005, 611 . 613 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 614 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 615 2006, . 617 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 618 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 619 December 2005, . 621 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 622 DOI 10.17487/RFC4302, December 2005, 623 . 625 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 626 RFC 4303, DOI 10.17487/RFC4303, December 2005, 627 . 629 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 630 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 631 DOI 10.17487/RFC4861, September 2007, 632 . 634 [RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast 635 Extensions to the Security Architecture for the Internet 636 Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008, 637 . 639 [RFC5415] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, 640 Ed., "Control And Provisioning of Wireless Access Points 641 (CAPWAP) Protocol Specification", RFC 5415, 642 DOI 10.17487/RFC5415, March 2009, 643 . 645 [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing 646 Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889, 647 September 2010, . 649 [RFC6059] Krishnan, S. and G. Daley, "Simple Procedures for 650 Detecting Network Attachment in IPv6", RFC 6059, 651 DOI 10.17487/RFC6059, November 2010, 652 . 654 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 655 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 656 2011, . 658 [RFC7042] Eastlake 3rd, D. and J. Abley, "IANA Considerations and 659 IETF Protocol and Documentation Usage for IEEE 802 660 Parameters", BCP 141, RFC 7042, DOI 10.17487/RFC7042, 661 October 2013, . 663 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 664 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 665 February 2014, . 667 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 668 Interface Identifiers with IPv6 Stateless Address 669 Autoconfiguration (SLAAC)", RFC 7217, 670 DOI 10.17487/RFC7217, April 2014, 671 . 673 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 674 Considerations for IPv6 Address Generation Mechanisms", 675 RFC 7721, DOI 10.17487/RFC7721, March 2016, 676 . 678 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 679 "Recommendation on Stable IPv6 Interface Identifiers", 680 RFC 8064, DOI 10.17487/RFC8064, February 2017, 681 . 683 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 684 (IPv6) Specification", STD 86, RFC 8200, 685 DOI 10.17487/RFC8200, July 2017, 686 . 688 9.2. Informative References 690 [ETSI-sec-archi] 691 "ETSI TS 102 940 V1.2.1 (2016-11), ETSI Technical 692 Specification, Intelligent Transport Systems (ITS); 693 Security; ITS communications security architecture and 694 security management, November 2016. Downloaded on 695 September 9th, 2017, freely available from ETSI website at 696 URL http://www.etsi.org/deliver/ 697 etsi_ts/102900_102999/102940/01.02.01_60/ 698 ts_102940v010201p.pdf". 700 [I-D.hinden-6man-rfc2464bis] 701 Crawford, M. and R. Hinden, "Transmission of IPv6 Packets 702 over Ethernet Networks", draft-hinden-6man-rfc2464bis-02 703 (work in progress), March 2017. 705 [I-D.ietf-ipwave-vehicular-networking-survey] 706 Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M. 707 Wetterwald, "Survey on IP-based Vehicular Networking for 708 Intelligent Transportation Systems", draft-ietf-ipwave- 709 vehicular-networking-survey-00 (work in progress), July 710 2017. 712 [I-D.ietf-mboned-ieee802-mcast-problems] 713 Perkins, C., McBride, M., Stanley, D., Kumari, W., and J. 714 Zuniga, "Multicast Considerations over IEEE 802 Wireless 715 Media", draft-ietf-mboned-ieee802-mcast-problems-04 (work 716 in progress), November 2018. 718 [IEEE-1609.2] 719 "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access 720 in Vehicular Environments (WAVE) -- Security Services for 721 Applications and Management Messages. Example URL 722 http://ieeexplore.ieee.org/document/7426684/ accessed on 723 August 17th, 2017.". 725 [IEEE-1609.3] 726 "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access 727 in Vehicular Environments (WAVE) -- Networking Services. 728 Example URL http://ieeexplore.ieee.org/document/7458115/ 729 accessed on August 17th, 2017.". 731 [IEEE-1609.4] 732 "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access 733 in Vehicular Environments (WAVE) -- Multi-Channel 734 Operation. Example URL 735 http://ieeexplore.ieee.org/document/7435228/ accessed on 736 August 17th, 2017.". 738 [IEEE-802.11-2016] 739 "IEEE Standard 802.11-2016 - IEEE Standard for Information 740 Technology - Telecommunications and information exchange 741 between systems Local and metropolitan area networks - 742 Specific requirements - Part 11: Wireless LAN Medium 743 Access Control (MAC) and Physical Layer (PHY) 744 Specifications. Status - Active Standard. Description 745 retrieved freely on September 12th, 2017, at URL 746 https://standards.ieee.org/findstds/ 747 standard/802.11-2016.html". 749 [IEEE-802.11p-2010] 750 "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information 751 Technology - Telecommunications and information exchange 752 between systems - Local and metropolitan area networks - 753 Specific requirements, Part 11: Wireless LAN Medium Access 754 Control (MAC) and Physical Layer (PHY) Specifications, 755 Amendment 6: Wireless Access in Vehicular Environments; 756 document freely available at URL 757 http://standards.ieee.org/getieee802/ 758 download/802.11p-2010.pdf retrieved on September 20th, 759 2013.". 761 Appendix A. ChangeLog 763 The changes are listed in reverse chronological order, most recent 764 changes appearing at the top of the list. 766 -33: substituted 'movement detection' for 'handover behaviour' in 767 introductory text; removed redundant phrase referring to Security 768 Considerations section; removed the phrase about forming mechanisms 769 being left out, as IP is not much concerned about L2 forming; moved 770 the Pseudonym section from main section to end of Security 771 Considerations section (and clarified 'concurrently'); capitalized 772 SHOULD consider OCB in WiFi multicast problems, and referred to more 773 recent I-D on topic; removed several phrases in a paragraph about 774 oui.txt and MAC presence in IPv6 address, as they are well known 775 info, but clarified the example of privacy risk of Company ID in MAC 776 addresses in public roads; clarified that ND MUST be used over 777 802.11-OCB. 779 -32: significantly shortened the relevant ND/OCB paragraph. It now 780 just states ND is used over OCB, w/o detailing. 782 -31: filled in the section titled "Pseudonym Handling"; removed a 783 'MAY NOT' phrase about possibility of having other prefix than the LL 784 on the link between cars; shortened and improved the paragraph about 785 Mobile IPv6, now with DNAv6; improved the ND text about ND 786 retransmissions with relationship to packet loss; changed the title 787 of an appendix from 'EPD' to 'Protocol Layering'; improved the 788 'Aspects introduced by OCB' appendix with a few phrases about the 789 channel use and references. 791 -30: a clarification on the reliability of ND over OCB and over 792 802.11. 794 -29: 796 o 797 -28: 799 o Created a new section 'Pseudonym Handling'. 801 o removed the 'Vehicle ID' appendix. 803 o improved the address generation from random MAC address. 805 o shortened Term IP-RSU definition. 807 o removed refs to two detail Clauses in IEEE documents, kept just 808 these latter. 810 -27: part 1 of addressing Human Rights review from IRTF. Removed 811 appendices F.2 and F.3. Shortened definition of IP-RSU. Removed 812 reference to 1609.4. A few other small changes, see diff. 814 -26: moved text from SLAAC section and from Design Considerations 815 appendix about privacy into a new Privacy Condiderations subsection 816 of the Security section; reformulated the SLAAC and IID sections to 817 stress only LLs can use EUI-64; removed the "GeoIP" wireshark 818 explanation; reformulated SLAAC and LL sections; added brief mention 819 of need of use LLs; clarified text about MAC address changes; dropped 820 pseudonym discussion; changed title of section describing examples of 821 packet formats. 823 -25: added a reference to 'IEEE Management Information Base', instead 824 of just 'Management Information Base'; added ref to further 825 appendices in the introductory phrases; improved text for IID 826 formation for SLAAC, inserting recommendation for RFC8064 before 827 RFC2464. 829 From draft-ietf-ipwave-ipv6-over-80211ocb-23 to draft-ietf-ipwave- 830 ipv6-over-80211ocb-24 832 o Nit: wrote "IPWAVE Working Group" on the front page, instead of 833 "Network Working Group". 835 o Addressed the comments on 6MAN: replaced a sentence about ND 836 problem with "is used over 802.11-OCB". 838 From draft-ietf-ipwave-ipv6-over-80211ocb-22 to draft-ietf-ipwave- 839 ipv6-over-80211ocb-23 841 o No content modifications, but check the entire draft chain on 842 IPv6-only: xml2rfc, submission on tools.ietf.org and datatracker. 844 From draft-ietf-ipwave-ipv6-over-80211ocb-21 to draft-ietf-ipwave- 845 ipv6-over-80211ocb-22 847 o Corrected typo, use dash in "802.11-OCB" instead of space. 849 o Improved the Frame Format section: MUST use QoSData, specify the 850 values within; clarified the Ethernet Adaptation Layer text. 852 From draft-ietf-ipwave-ipv6-over-80211ocb-20 to draft-ietf-ipwave- 853 ipv6-over-80211ocb-21 855 o Corrected a few nits and added names in Acknowledgments section. 857 o Removed unused reference to old Internet Draft tsvwg about QoS. 859 From draft-ietf-ipwave-ipv6-over-80211ocb-19 to draft-ietf-ipwave- 860 ipv6-over-80211ocb-20 862 o Reduced the definition of term "802.11-OCB". 864 o Left out of this specification which 802.11 header to use to 865 transmit IP packets in OCB mode (QoS Data header, Data header, or 866 any other). 868 o Added 'MUST' use an Ethernet Adaptation Layer, instead of 'is 869 using' an Ethernet Adaptation Layer. 871 From draft-ietf-ipwave-ipv6-over-80211ocb-18 to draft-ietf-ipwave- 872 ipv6-over-80211ocb-19 874 o Removed the text about fragmentation. 876 o Removed the mentioning of WSMP and GeoNetworking. 878 o Removed the explanation of the binary representation of the 879 EtherType. 881 o Rendered normative the paragraph about unicast and multicast 882 address mapping. 884 o Removed paragraph about addressing model, subnet structure and 885 easiness of using LLs. 887 o Clarified the Type/Subtype field in the 802.11 Header. 889 o Used RECOMMENDED instead of recommended, for the stable interface 890 identifiers. 892 From draft-ietf-ipwave-ipv6-over-80211ocb-17 to draft-ietf-ipwave- 893 ipv6-over-80211ocb-18 895 o Improved the MTU and fragmentation paragraph. 897 From draft-ietf-ipwave-ipv6-over-80211ocb-16 to draft-ietf-ipwave- 898 ipv6-over-80211ocb-17 900 o Susbtituted "MUST be increased" to "is increased" in the MTU 901 section, about fragmentation. 903 From draft-ietf-ipwave-ipv6-over-80211ocb-15 to draft-ietf-ipwave- 904 ipv6-over-80211ocb-16 906 o Removed the definition of the 'WiFi' term and its occurences. 907 Clarified a phrase that used it in Appendix C "Aspects introduced 908 by the OCB mode to 802.11". 910 o Added more normative words: MUST be 0x86DD, MUST fragment if size 911 larger than MTU, Sequence number in 802.11 Data header MUST be 912 increased. 914 From draft-ietf-ipwave-ipv6-over-80211ocb-14 to draft-ietf-ipwave- 915 ipv6-over-80211ocb-15 917 o Added normative term MUST in two places in section "Ethernet 918 Adaptation Layer". 920 From draft-ietf-ipwave-ipv6-over-80211ocb-13 to draft-ietf-ipwave- 921 ipv6-over-80211ocb-14 923 o Created a new Appendix titled "Extra Terminology" that contains 924 terms DSRC, DSRCS, OBU, RSU as defined outside IETF. Some of them 925 are used in the main Terminology section. 927 o Added two paragraphs explaining that ND and Mobile IPv6 have 928 problems working over 802.11-OCB, yet their adaptations is not 929 specified in this document. 931 From draft-ietf-ipwave-ipv6-over-80211ocb-12 to draft-ietf-ipwave- 932 ipv6-over-80211ocb-13 934 o Substituted "IP-OBU" for "OBRU", and "IP-RSU" for "RSRU" 935 throughout and improved OBU-related definitions in the Terminology 936 section. 938 From draft-ietf-ipwave-ipv6-over-80211ocb-11 to draft-ietf-ipwave- 939 ipv6-over-80211ocb-12 940 o Improved the appendix about "MAC Address Generation" by expressing 941 the technique to be an optional suggestion, not a mandatory 942 mechanism. 944 From draft-ietf-ipwave-ipv6-over-80211ocb-10 to draft-ietf-ipwave- 945 ipv6-over-80211ocb-11 947 o Shortened the paragraph on forming/terminating 802.11-OCB links. 949 o Moved the draft tsvwg-ieee-802-11 to Informative References. 951 From draft-ietf-ipwave-ipv6-over-80211ocb-09 to draft-ietf-ipwave- 952 ipv6-over-80211ocb-10 954 o Removed text requesting a new Group ID for multicast for OCB. 956 o Added a clarification of the meaning of value "3333" in the 957 section Address Mapping -- Multicast. 959 o Added note clarifying that in Europe the regional authority is not 960 ETSI, but "ECC/CEPT based on ENs from ETSI". 962 o Added note stating that the manner in which two STAtions set their 963 communication channel is not described in this document. 965 o Added a time qualifier to state that the "each node is represented 966 uniquely at a certain point in time." 968 o Removed text "This section may need to be moved" (the "Reliability 969 Requirements" section). This section stays there at this time. 971 o In the term definition "802.11-OCB" added a note stating that "any 972 implementation should comply with standards and regulations set in 973 the different countries for using that frequency band." 975 o In the RSU term definition, added a sentence explaining the 976 difference between RSU and RSRU: in terms of number of interfaces 977 and IP forwarding. 979 o Replaced "with at least two IP interfaces" with "with at least two 980 real or virtual IP interfaces". 982 o Added a term in the Terminology for "OBU". However the definition 983 is left empty, as this term is defined outside IETF. 985 o Added a clarification that it is an OBU or an OBRU in this phrase 986 "A vehicle embarking an OBU or an OBRU". 988 o Checked the entire document for a consistent use of terms OBU and 989 OBRU. 991 o Added note saying that "'p' is a letter identifying the 992 Ammendment". 994 o Substituted lower case for capitals SHALL or MUST in the 995 Appendices. 997 o Added reference to RFC7042, helpful in the 3333 explanation. 998 Removed reference to individual submission draft-petrescu-its- 999 scenario-reqs and added reference to draft-ietf-ipwave-vehicular- 1000 networking-survey. 1002 o Added figure captions, figure numbers, and references to figure 1003 numbers instead of 'below'. Replaced "section Section" with 1004 "section" throughout. 1006 o Minor typographical errors. 1008 From draft-ietf-ipwave-ipv6-over-80211ocb-08 to draft-ietf-ipwave- 1009 ipv6-over-80211ocb-09 1011 o Significantly shortened the Address Mapping sections, by text 1012 copied from RFC2464, and rather referring to it. 1014 o Moved the EPD description to an Appendix on its own. 1016 o Shortened the Introduction and the Abstract. 1018 o Moved the tutorial section of OCB mode introduced to .11, into an 1019 appendix. 1021 o Removed the statement that suggests that for routing purposes a 1022 prefix exchange mechanism could be needed. 1024 o Removed refs to RFC3963, RFC4429 and RFC6775; these are about ND, 1025 MIP/NEMO and oDAD; they were referred in the handover discussion 1026 section, which is out. 1028 o Updated a reference from individual submission to now a WG item in 1029 IPWAVE: the survey document. 1031 o Added term definition for WiFi. 1033 o Updated the authorship and expanded the Contributors section. 1035 o Corrected typographical errors. 1037 From draft-ietf-ipwave-ipv6-over-80211ocb-07 to draft-ietf-ipwave- 1038 ipv6-over-80211ocb-08 1040 o Removed the per-channel IPv6 prohibition text. 1042 o Corrected typographical errors. 1044 From draft-ietf-ipwave-ipv6-over-80211ocb-06 to draft-ietf-ipwave- 1045 ipv6-over-80211ocb-07 1047 o Added new terms: OBRU and RSRU ('R' for Router). Refined the 1048 existing terms RSU and OBU, which are no longer used throughout 1049 the document. 1051 o Improved definition of term "802.11-OCB". 1053 o Clarified that OCB does not "strip" security, but that the 1054 operation in OCB mode is "stripped off of all .11 security". 1056 o Clarified that theoretical OCB bandwidth speed is 54mbits, but 1057 that a commonly observed bandwidth in IP-over-OCB is 12mbit/s. 1059 o Corrected typographical errors, and improved some phrasing. 1061 From draft-ietf-ipwave-ipv6-over-80211ocb-05 to draft-ietf-ipwave- 1062 ipv6-over-80211ocb-06 1064 o Updated references of 802.11-OCB document from -2012 to the IEEE 1065 802.11-2016. 1067 o In the LL address section, and in SLAAC section, added references 1068 to 7217 opaque IIDs and 8064 stable IIDs. 1070 From draft-ietf-ipwave-ipv6-over-80211ocb-04 to draft-ietf-ipwave- 1071 ipv6-over-80211ocb-05 1073 o Lengthened the title and cleanded the abstract. 1075 o Added text suggesting LLs may be easy to use on OCB, rather than 1076 GUAs based on received prefix. 1078 o Added the risks of spoofing and hijacking. 1080 o Removed the text speculation on adoption of the TSA message. 1082 o Clarified that the ND protocol is used. 1084 o Clarified what it means "No association needed". 1086 o Added some text about how two STAs discover each other. 1088 o Added mention of external (OCB) and internal network (stable), in 1089 the subnet structure section. 1091 o Added phrase explaining that both .11 Data and .11 QoS Data 1092 headers are currently being used, and may be used in the future. 1094 o Moved the packet capture example into an Appendix Implementation 1095 Status. 1097 o Suggested moving the reliability requirements appendix out into 1098 another document. 1100 o Added a IANA Consiserations section, with content, requesting for 1101 a new multicast group "all OCB interfaces". 1103 o Added new OBU term, improved the RSU term definition, removed the 1104 ETTC term, replaced more occurences of 802.11p, 802.11-OCB with 1105 802.11-OCB. 1107 o References: 1109 * Added an informational reference to ETSI's IPv6-over- 1110 GeoNetworking. 1112 * Added more references to IETF and ETSI security protocols. 1114 * Updated some references from I-D to RFC, and from old RFC to 1115 new RFC numbers. 1117 * Added reference to multicast extensions to IPsec architecture 1118 RFC. 1120 * Added a reference to 2464-bis. 1122 * Removed FCC informative references, because not used. 1124 o Updated the affiliation of one author. 1126 o Reformulation of some phrases for better readability, and 1127 correction of typographical errors. 1129 From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave- 1130 ipv6-over-80211ocb-04 1132 o Removed a few informative references pointing to Dx draft IEEE 1133 1609 documents. 1135 o Removed outdated informative references to ETSI documents. 1137 o Added citations to IEEE 1609.2, .3 and .4-2016. 1139 o Minor textual issues. 1141 From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave- 1142 ipv6-over-80211ocb-03 1144 o Keep the previous text on multiple addresses, so remove talk about 1145 MIP6, NEMOv6 and MCoA. 1147 o Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon. 1149 o Clarified the figure showing Infrastructure mode and OCB mode side 1150 by side. 1152 o Added a reference to the IP Security Architecture RFC. 1154 o Detailed the IPv6-per-channel prohibition paragraph which reflects 1155 the discussion at the last IETF IPWAVE WG meeting. 1157 o Added section "Address Mapping -- Unicast". 1159 o Added the ".11 Trailer" to pictures of 802.11 frames. 1161 o Added text about SNAP carrying the Ethertype. 1163 o New RSU definition allowing for it be both a Router and not 1164 necessarily a Router some times. 1166 o Minor textual issues. 1168 From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave- 1169 ipv6-over-80211ocb-02 1171 o Replaced almost all occurences of 802.11p with 802.11-OCB, leaving 1172 only when explanation of evolution was necessary. 1174 o Shortened by removing parameter details from a paragraph in the 1175 Introduction. 1177 o Moved a reference from Normative to Informative. 1179 o Added text in intro clarifying there is no handover spec at IEEE, 1180 and that 1609.2 does provide security services. 1182 o Named the contents the fields of the EthernetII header (including 1183 the Ethertype bitstring). 1185 o Improved relationship between two paragraphs describing the 1186 increase of the Sequence Number in 802.11 header upon IP 1187 fragmentation. 1189 o Added brief clarification of "tracking". 1191 From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave- 1192 ipv6-over-80211ocb-01 1194 o Introduced message exchange diagram illustrating differences 1195 between 802.11 and 802.11 in OCB mode. 1197 o Introduced an appendix listing for information the set of 802.11 1198 messages that may be transmitted in OCB mode. 1200 o Removed appendix sections "Privacy Requirements", "Authentication 1201 Requirements" and "Security Certificate Generation". 1203 o Removed appendix section "Non IP Communications". 1205 o Introductory phrase in the Security Considerations section. 1207 o Improved the definition of "OCB". 1209 o Introduced theoretical stacked layers about IPv6 and IEEE layers 1210 including EPD. 1212 o Removed the appendix describing the details of prohibiting IPv6 on 1213 certain channels relevant to 802.11-OCB. 1215 o Added a brief reference in the privacy text about a precise clause 1216 in IEEE 1609.3 and .4. 1218 o Clarified the definition of a Road Side Unit. 1220 o Removed the discussion about security of WSA (because is non-IP). 1222 o Removed mentioning of the GeoNetworking discussion. 1224 o Moved references to scientific articles to a separate 'overview' 1225 draft, and referred to it. 1227 Appendix B. 802.11p 1229 The term "802.11p" is an earlier definition. The behaviour of 1230 "802.11p" networks is rolled in the document IEEE Std 802.11-2016. 1231 In that document the term 802.11p disappears. Instead, each 802.11p 1232 feature is conditioned by the IEEE Management Information Base (MIB) 1233 attribute "OCBActivated" [IEEE-802.11-2016]. Whenever OCBActivated 1234 is set to true the IEEE Std 802.11-OCB state is activated. For 1235 example, an 802.11 STAtion operating outside the context of a basic 1236 service set has the OCBActivated flag set. Such a station, when it 1237 has the flag set, uses a BSS identifier equal to ff:ff:ff:ff:ff:ff. 1239 Appendix C. Aspects introduced by the OCB mode to 802.11 1241 In the IEEE 802.11-OCB mode, all nodes in the wireless range can 1242 directly communicate with each other without involving authentication 1243 or association procedures. In OCB mode, the manner in which channels 1244 are selected and used is simplified compared to when in BSS mode. 1245 Contrary to BSS mode, at link layer, it is necessary to set 1246 statically the same channel number (or frequency) on two stations 1247 that need to communicate with each other (in BSS mode this channel 1248 set operation is performed automatically during 'scanning'). The 1249 manner in which stations set their channel number in OCB mode is not 1250 specified in this document. Stations STA1 and STA2 can exchange IP 1251 packets only if they are set on the same channel. At IP layer, they 1252 then discover each other by using the IPv6 Neighbor Discovery 1253 protocol. The allocation of a particular channel for a particular 1254 use is defined statically in standards authored by ETSI (in Europe), 1255 FCC in America, and similar organisations in South Korea, Japan and 1256 other parts of the world. 1258 Briefly, the IEEE 802.11-OCB mode has the following properties: 1260 o The use by each node of a 'wildcard' BSSID (i.e., each bit of the 1261 BSSID is set to 1) 1263 o No IEEE 802.11 Beacon frames are transmitted 1265 o No authentication is required in order to be able to communicate 1267 o No association is needed in order to be able to communicate 1269 o No encryption is provided in order to be able to communicate 1271 o Flag dot11OCBActivated is set to true 1273 All the nodes in the radio communication range (IP-OBU and IP-RSU) 1274 receive all the messages transmitted (IP-OBU and IP-RSU) within the 1275 radio communications range. The eventual conflict(s) are resolved by 1276 the MAC CDMA function. 1278 The message exchange diagram in Figure 3 illustrates a comparison 1279 between traditional 802.11 and 802.11 in OCB mode. The 'Data' 1280 messages can be IP packets such as HTTP or others. Other 802.11 1281 management and control frames (non IP) may be transmitted, as 1282 specified in the 802.11 standard. For information, the names of 1283 these messages as currently specified by the 802.11 standard are 1284 listed in Appendix G. 1286 STA AP STA1 STA2 1287 | | | | 1288 |<------ Beacon -------| |<------ Data -------->| 1289 | | | | 1290 |---- Probe Req. ----->| |<------ Data -------->| 1291 |<--- Probe Res. ------| | | 1292 | | |<------ Data -------->| 1293 |---- Auth Req. ------>| | | 1294 |<--- Auth Res. -------| |<------ Data -------->| 1295 | | | | 1296 |---- Asso Req. ------>| |<------ Data -------->| 1297 |<--- Asso Res. -------| | | 1298 | | |<------ Data -------->| 1299 |<------ Data -------->| | | 1300 |<------ Data -------->| |<------ Data -------->| 1302 (i) 802.11 Infrastructure mode (ii) 802.11-OCB mode 1304 Figure 3: Difference between messages exchanged on 802.11 (left) and 1305 802.11-OCB (right) 1307 The interface 802.11-OCB was specified in IEEE Std 802.11p (TM) -2010 1308 [IEEE-802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, 1309 titled "Amendment 6: Wireless Access in Vehicular Environments". 1310 Since then, this amendment has been integrated in IEEE 802.11(TM) 1311 -2012 and -2016 [IEEE-802.11-2016]. 1313 In document 802.11-2016, anything qualified specifically as 1314 "OCBActivated", or "outside the context of a basic service" set to be 1315 true, then it is actually referring to OCB aspects introduced to 1316 802.11. 1318 In order to delineate the aspects introduced by 802.11-OCB to 802.11, 1319 we refer to the earlier [IEEE-802.11p-2010]. The amendment is 1320 concerned with vehicular communications, where the wireless link is 1321 similar to that of Wireless LAN (using a PHY layer specified by 1322 802.11a/b/g/n), but which needs to cope with the high mobility factor 1323 inherent in scenarios of communications between moving vehicles, and 1324 between vehicles and fixed infrastructure deployed along roads. 1325 While 'p' is a letter identifying the Ammendment, just like 'a, b, g' 1326 and 'n' are, 'p' is concerned more with MAC modifications, and a 1327 little with PHY modifications; the others are mainly about PHY 1328 modifications. It is possible in practice to combine a 'p' MAC with 1329 an 'a' PHY by operating outside the context of a BSS with OFDM at 1330 5.4GHz and 5.9GHz. 1332 The 802.11-OCB links are specified to be compatible as much as 1333 possible with the behaviour of 802.11a/b/g/n and future generation 1334 IEEE WLAN links. From the IP perspective, an 802.11-OCB MAC layer 1335 offers practically the same interface to IP as the 802.11a/b/g/n and 1336 802.3. A packet sent by an IP-OBU may be received by one or multiple 1337 IP-RSUs. The link-layer resolution is performed by using the IPv6 1338 Neighbor Discovery protocol. 1340 To support this similarity statement (IPv6 is layered on top of LLC 1341 on top of 802.11-OCB, in the same way that IPv6 is layered on top of 1342 LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on 1343 top of 802.3 (for Ethernet)) it is useful to analyze the differences 1344 between 802.11-OCB and 802.11 specifications. During this analysis, 1345 we note that whereas 802.11-OCB lists relatively complex and numerous 1346 changes to the MAC layer (and very little to the PHY layer), there 1347 are only a few characteristics which may be important for an 1348 implementation transmitting IPv6 packets on 802.11-OCB links. 1350 The most important 802.11-OCB point which influences the IPv6 1351 functioning is the OCB characteristic; an additional, less direct 1352 influence, is the maximum bandwidth afforded by the PHY modulation/ 1353 demodulation methods and channel access specified by 802.11-OCB. The 1354 maximum bandwidth theoretically possible in 802.11-OCB is 54 Mbit/s 1355 (when using, for example, the following parameters: 20 MHz channel; 1356 modulation 64-QAM; coding rate R is 3/4); in practice of IP-over- 1357 802.11-OCB a commonly observed figure is 12Mbit/s; this bandwidth 1358 allows the operation of a wide range of protocols relying on IPv6. 1360 o Operation Outside the Context of a BSS (OCB): the (earlier 1361 802.11p) 802.11-OCB links are operated without a Basic Service Set 1362 (BSS). This means that the frames IEEE 802.11 Beacon, Association 1363 Request/Response, Authentication Request/Response, and similar, 1364 are not used. The used identifier of BSS (BSSID) has a 1365 hexadecimal value always 0xffffffffffff (48 '1' bits, represented 1366 as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' 1367 BSSID), as opposed to an arbitrary BSSID value set by 1368 administrator (e.g. 'My-Home-AccessPoint'). The OCB operation - 1369 namely the lack of beacon-based scanning and lack of 1370 authentication - should be taken into account when the Mobile IPv6 1371 protocol [RFC6275] and the protocols for IP layer security 1372 [RFC4301] are used. The way these protocols adapt to OCB is not 1373 described in this document. 1375 o Timing Advertisement: is a new message defined in 802.11-OCB, 1376 which does not exist in 802.11a/b/g/n. This message is used by 1377 stations to inform other stations about the value of time. It is 1378 similar to the time as delivered by a GNSS system (Galileo, GPS, 1379 ...) or by a cellular system. This message is optional for 1380 implementation. 1382 o Frequency range: this is a characteristic of the PHY layer, with 1383 almost no impact on the interface between MAC and IP. However, it 1384 is worth considering that the frequency range is regulated by a 1385 regional authority (ARCEP, ECC/CEPT based on ENs from ETSI, FCC, 1386 etc.); as part of the regulation process, specific applications 1387 are associated with specific frequency ranges. In the case of 1388 802.11-OCB, the regulator associates a set of frequency ranges, or 1389 slots within a band, to the use of applications of vehicular 1390 communications, in a band known as "5.9GHz". The 5.9GHz band is 1391 different from the 2.4GHz and 5GHz bands used by Wireless LAN. 1392 However, as with Wireless LAN, the operation of 802.11-OCB in 1393 "5.9GHz" bands is exempt from owning a license in EU (in US the 1394 5.9GHz is a licensed band of spectrum; for the fixed 1395 infrastructure an explicit FCC authorization is required; for an 1396 on-board device a 'licensed-by-rule' concept applies: rule 1397 certification conformity is required.) Technical conditions are 1398 different than those of the bands "2.4GHz" or "5GHz". The allowed 1399 power levels, and implicitly the maximum allowed distance between 1400 vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20 1401 dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum 1402 distance of approximately 1km, compared to approximately 50m. 1403 Additionally, specific conditions related to congestion avoidance, 1404 jamming avoidance, and radar detection are imposed on the use of 1405 DSRC (in US) and on the use of frequencies for Intelligent 1406 Transportation Systems (in EU), compared to Wireless LAN 1407 (802.11a/b/g/n). 1409 o 'Half-rate' encoding: as the frequency range, this parameter is 1410 related to PHY, and thus has not much impact on the interface 1411 between the IP layer and the MAC layer. 1413 o In vehicular communications using 802.11-OCB links, there are 1414 strong privacy requirements with respect to addressing. While the 1415 802.11-OCB standard does not specify anything in particular with 1416 respect to MAC addresses, in these settings there exists a strong 1417 need for dynamic change of these addresses (as opposed to the non- 1418 vehicular settings - real wall protection - where fixed MAC 1419 addresses do not currently pose some privacy risks). This is 1420 further described in Section 5. A relevant function is described 1421 in documents IEEE 1609.3-2016 [IEEE-1609.3] and IEEE 1609.4-2016 1422 [IEEE-1609.4]. 1424 Appendix D. Changes Needed on a software driver 802.11a to become a 1425 802.11-OCB driver 1427 The 802.11p amendment modifies both the 802.11 stack's physical and 1428 MAC layers but all the induced modifications can be quite easily 1429 obtained by modifying an existing 802.11a ad-hoc stack. 1431 Conditions for a 802.11a hardware to be 802.11-OCB compliant: 1433 o The PHY entity shall be an orthogonal frequency division 1434 multiplexing (OFDM) system. It must support the frequency bands 1435 on which the regulator recommends the use of ITS communications, 1436 for example using IEEE 802.11-OCB layer, in France: 5875MHz to 1437 5925MHz. 1439 o The OFDM system must provide a "half-clocked" operation using 10 1440 MHz channel spacings. 1442 o The chip transmit spectrum mask must be compliant to the "Transmit 1443 spectrum mask" from the IEEE 802.11p amendment (but experimental 1444 environments tolerate otherwise). 1446 o The chip should be able to transmit up to 44.8 dBm when used by 1447 the US government in the United States, and up to 33 dBm in 1448 Europe; other regional conditions apply. 1450 Changes needed on the network stack in OCB mode: 1452 o Physical layer: 1454 * The chip must use the Orthogonal Frequency Multiple Access 1455 (OFDM) encoding mode. 1457 * The chip must be set in half-mode rate mode (the internal clock 1458 frequency is divided by two). 1460 * The chip must use dedicated channels and should allow the use 1461 of higher emission powers. This may require modifications to 1462 the local computer file that describes regulatory domains 1463 rules, if used by the kernel to enforce local specific 1464 restrictions. Such modifications to the local computer file 1465 must respect the location-specific regulatory rules. 1467 MAC layer: 1469 * All management frames (beacons, join, leave, and others) 1470 emission and reception must be disabled except for frames of 1471 subtype Action and Timing Advertisement (defined below). 1473 * No encryption key or method must be used. 1475 * Packet emission and reception must be performed as in ad-hoc 1476 mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff). 1478 * The functions related to joining a BSS (Association Request/ 1479 Response) and for authentication (Authentication Request/Reply, 1480 Challenge) are not called. 1482 * The beacon interval is always set to 0 (zero). 1484 * Timing Advertisement frames, defined in the amendment, should 1485 be supported. The upper layer should be able to trigger such 1486 frames emission and to retrieve information contained in 1487 received Timing Advertisements. 1489 Appendix E. Protocol Layering 1491 A more theoretical and detailed view of layer stacking, and 1492 interfaces between the IP layer and 802.11-OCB layers, is illustrated 1493 in Figure 4. The IP layer operates on top of the EtherType Protocol 1494 Discrimination (EPD); this Discrimination layer is described in IEEE 1495 Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP 1496 (Link Layer Control Service Access Point). 1498 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1499 | IPv6 | 1500 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ 1501 { LLC_SAP } 802.11-OCB 1502 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary 1503 | EPD | | | 1504 | | MLME | | 1505 +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | 1506 | MAC Sublayer | | | 802.11-OCB 1507 | and ch. coord. | | SME | Services 1508 +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | 1509 | | PLME | | 1510 | PHY Layer | PLME_SAP | 1511 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1513 Figure 4: EtherType Protocol Discrimination 1515 Appendix F. Design Considerations 1517 The networks defined by 802.11-OCB are in many ways similar to other 1518 networks of the 802.11 family. In theory, the encapsulation of IPv6 1519 over 802.11-OCB could be very similar to the operation of IPv6 over 1520 other networks of the 802.11 family. However, the high mobility, 1521 strong link asymmetry and very short connection makes the 802.11-OCB 1522 link significantly different from other 802.11 networks. Also, the 1523 automotive applications have specific requirements for reliability, 1524 security and privacy, which further add to the particularity of the 1525 802.11-OCB link. 1527 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode 1529 For information, at the time of writing, this is the list of IEEE 1530 802.11 messages that may be transmitted in OCB mode, i.e. when 1531 dot11OCBActivated is true in a STA: 1533 o The STA may send management frames of subtype Action and, if the 1534 STA maintains a TSF Timer, subtype Timing Advertisement; 1536 o The STA may send control frames, except those of subtype PS-Poll, 1537 CF-End, and CF-End plus CFAck; 1539 o The STA may send data frames of subtype Data, Null, QoS Data, and 1540 QoS Null. 1542 Appendix H. Examples of Packet Formats 1544 This section describes an example of an IPv6 Packet captured over a 1545 IEEE 802.11-OCB link. 1547 By way of example we show that there is no modification in the 1548 headers when transmitted over 802.11-OCB networks - they are 1549 transmitted like any other 802.11 and Ethernet packets. 1551 We describe an experiment of capturing an IPv6 packet on an 1552 802.11-OCB link. In topology depicted in Figure 5, the packet is an 1553 IPv6 Router Advertisement. This packet is emitted by a Router on its 1554 802.11-OCB interface. The packet is captured on the Host, using a 1555 network protocol analyzer (e.g. Wireshark); the capture is performed 1556 in two different modes: direct mode and 'monitor' mode. The topology 1557 used during the capture is depicted below. 1559 The packet is captured on the Host. The Host is an IP-OBU containing 1560 an 802.11 interface in format PCI express (an ITRI product). The 1561 kernel runs the ath5k software driver with modifications for OCB 1562 mode. The capture tool is Wireshark. The file format for save and 1563 analyze is 'pcap'. The packet is generated by the Router. The 1564 Router is an IP-RSU (ITRI product). 1566 +--------+ +-------+ 1567 | | 802.11-OCB Link | | 1568 ---| Router |--------------------------------| Host | 1569 | | | | 1570 +--------+ +-------+ 1572 Figure 5: Topology for capturing IP packets on 802.11-OCB 1574 During several capture operations running from a few moments to 1575 several hours, no message relevant to the BSSID contexts were 1576 captured (no Association Request/Response, Authentication Req/Resp, 1577 Beacon). This shows that the operation of 802.11-OCB is outside the 1578 context of a BSSID. 1580 Overall, the captured message is identical with a capture of an IPv6 1581 packet emitted on a 802.11b interface. The contents are precisely 1582 similar. 1584 H.1. Capture in Monitor Mode 1586 The IPv6 RA packet captured in monitor mode is illustrated below. 1587 The radio tap header provides more flexibility for reporting the 1588 characteristics of frames. The Radiotap Header is prepended by this 1589 particular stack and operating system on the Host machine to the RA 1590 packet received from the network (the Radiotap Header is not present 1591 on the air). The implementation-dependent Radiotap Header is useful 1592 for piggybacking PHY information from the chip's registers as data in 1593 a packet understandable by userland applications using Socket 1594 interfaces (the PHY interface can be, for example: power levels, data 1595 rate, ratio of signal to noise). 1597 The packet present on the air is formed by IEEE 802.11 Data Header, 1598 Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. 1600 Radiotap Header v0 1601 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1602 |Header Revision| Header Pad | Header length | 1603 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1604 | Present flags | 1605 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1606 | Data Rate | Pad | 1607 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1609 IEEE 802.11 Data Header 1610 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1611 | Type/Subtype and Frame Ctrl | Duration | 1612 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1613 | Receiver Address... 1614 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1615 ... Receiver Address | Transmitter Address... 1616 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1617 ... Transmitter Address | 1618 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1619 | BSS Id... 1620 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1621 ... BSS Id | Frag Number and Seq Number | 1622 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1624 Logical-Link Control Header 1625 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1626 | DSAP |I| SSAP |C| Control field | Org. code... 1627 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1628 ... Organizational Code | Type | 1629 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1630 IPv6 Base Header 1631 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1632 |Version| Traffic Class | Flow Label | 1633 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1634 | Payload Length | Next Header | Hop Limit | 1635 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1636 | | 1637 + + 1638 | | 1639 + Source Address + 1640 | | 1641 + + 1642 | | 1643 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1644 | | 1645 + + 1646 | | 1647 + Destination Address + 1648 | | 1649 + + 1650 | | 1651 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1653 Router Advertisement 1654 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1655 | Type | Code | Checksum | 1656 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1657 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1658 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1659 | Reachable Time | 1660 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1661 | Retrans Timer | 1662 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1663 | Options ... 1664 +-+-+-+-+-+-+-+-+-+-+-+- 1666 The value of the Data Rate field in the Radiotap header is set to 6 1667 Mb/s. This indicates the rate at which this RA was received. 1669 The value of the Transmitter address in the IEEE 802.11 Data Header 1670 is set to a 48bit value. The value of the destination address is 1671 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS 1672 Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network 1673 protocol analyzer as being "broadcast". The Fragment number and 1674 sequence number fields are together set to 0x90C6. 1676 The value of the Organization Code field in the Logical-Link Control 1677 Header is set to 0x0, recognized as "Encapsulated Ethernet". The 1678 value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise 1679 #86DD), recognized as "IPv6". 1681 A Router Advertisement is periodically sent by the router to 1682 multicast group address ff02::1. It is an icmp packet type 134. The 1683 IPv6 Neighbor Discovery's Router Advertisement message contains an 1684 8-bit field reserved for single-bit flags, as described in [RFC4861]. 1686 The IPv6 header contains the link local address of the router 1687 (source) configured via EUI-64 algorithm, and destination address set 1688 to ff02::1. 1690 The Ethernet Type field in the logical-link control header is set to 1691 0x86dd which indicates that the frame transports an IPv6 packet. In 1692 the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 1693 which is the corresponding multicast MAC address. The BSS id is a 1694 broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link 1695 duration between vehicles and the roadside infrastructure, there is 1696 no need in IEEE 802.11-OCB to wait for the completion of association 1697 and authentication procedures before exchanging data. IEEE 1698 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) 1699 and may start communicating as soon as they arrive on the 1700 communication channel. 1702 H.2. Capture in Normal Mode 1704 The same IPv6 Router Advertisement packet described above (monitor 1705 mode) is captured on the Host, in the Normal mode, and depicted 1706 below. 1708 Ethernet II Header 1709 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1710 | Destination... 1711 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1712 ...Destination | Source... 1713 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1714 ...Source | 1715 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1716 | Type | 1717 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1719 IPv6 Base Header 1720 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1721 |Version| Traffic Class | Flow Label | 1722 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1723 | Payload Length | Next Header | Hop Limit | 1724 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1725 | | 1726 + + 1727 | | 1728 + Source Address + 1729 | | 1730 + + 1731 | | 1732 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1733 | | 1734 + + 1735 | | 1736 + Destination Address + 1737 | | 1738 + + 1739 | | 1740 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1742 Router Advertisement 1743 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1744 | Type | Code | Checksum | 1745 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1746 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1747 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1748 | Reachable Time | 1749 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1750 | Retrans Timer | 1751 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1752 | Options ... 1753 +-+-+-+-+-+-+-+-+-+-+-+- 1755 One notices that the Radiotap Header, the IEEE 802.11 Data Header and 1756 the Logical-Link Control Headers are not present. On the other hand, 1757 a new header named Ethernet II Header is present. 1759 The Destination and Source addresses in the Ethernet II header 1760 contain the same values as the fields Receiver Address and 1761 Transmitter Address present in the IEEE 802.11 Data Header in the 1762 "monitor" mode capture. 1764 The value of the Type field in the Ethernet II header is 0x86DD 1765 (recognized as "IPv6"); this value is the same value as the value of 1766 the field Type in the Logical-Link Control Header in the "monitor" 1767 mode capture. 1769 The knowledgeable experimenter will no doubt notice the similarity of 1770 this Ethernet II Header with a capture in normal mode on a pure 1771 Ethernet cable interface. 1773 An Adaptation layer is inserted on top of a pure IEEE 802.11 MAC 1774 layer, in order to adapt packets, before delivering the payload data 1775 to the applications. It adapts 802.11 LLC/MAC headers to Ethernet II 1776 headers. In further detail, this adaptation consists in the 1777 elimination of the Radiotap, 802.11 and LLC headers, and in the 1778 insertion of the Ethernet II header. In this way, IPv6 runs straight 1779 over LLC over the 802.11-OCB MAC layer; this is further confirmed by 1780 the use of the unique Type 0x86DD. 1782 Appendix I. Extra Terminology 1784 The following terms are defined outside the IETF. They are used to 1785 define the main terms in the main terminology section Section 2. 1787 DSRC (Dedicated Short Range Communication): a term defined outside 1788 the IETF. The US Federal Communications Commission (FCC) Dedicated 1789 Short Range Communication (DSRC) is defined in the Code of Federal 1790 Regulations (CFR) 47, Parts 90 and 95. This Code is referred in the 1791 definitions below. At the time of the writing of this Internet 1792 Draft, the last update of this Code was dated October 1st, 2010. 1794 DSRCS (Dedicated Short-Range Communications Services): a term defined 1795 outside the IETF. The use of radio techniques to transfer data over 1796 short distances between roadside and mobile units, between mobile 1797 units, and between portable and mobile units to perform operations 1798 related to the improvement of traffic flow, traffic safety, and other 1799 intelligent transportation service applications in a variety of 1800 environments. DSRCS systems may also transmit status and 1801 instructional messages related to the units involve. [Ref. 47 CFR 1802 90.7 - Definitions] 1803 OBU (On-Board Unit): a term defined outside the IETF. An On-Board 1804 Unit is a DSRCS transceiver that is normally mounted in or on a 1805 vehicle, or which in some instances may be a portable unit. An OBU 1806 can be operational while a vehicle or person is either mobile or 1807 stationary. The OBUs receive and contend for time to transmit on one 1808 or more radio frequency (RF) channels. Except where specifically 1809 excluded, OBU operation is permitted wherever vehicle operation or 1810 human passage is permitted. The OBUs mounted in vehicles are 1811 licensed by rule under part 95 of the respective chapter and 1812 communicate with Roadside Units (RSUs) and other OBUs. Portable OBUs 1813 are also licensed by rule under part 95 of the respective chapter. 1814 OBU operations in the Unlicensed National Information Infrastructure 1815 (UNII) Bands follow the rules in those bands. - [CFR 90.7 - 1816 Definitions]. 1818 RSU (Road-Side Unit): a term defined outside of IETF. A Roadside 1819 Unit is a DSRC transceiver that is mounted along a road or pedestrian 1820 passageway. An RSU may also be mounted on a vehicle or is hand 1821 carried, but it may only operate when the vehicle or hand- carried 1822 unit is stationary. Furthermore, an RSU operating under the 1823 respectgive part is restricted to the location where it is licensed 1824 to operate. However, portable or hand-held RSUs are permitted to 1825 operate where they do not interfere with a site-licensed operation. 1826 A RSU broadcasts data to OBUs or exchanges data with OBUs in its 1827 communications zone. An RSU also provides channel assignments and 1828 operating instructions to OBUs in its communications zone, when 1829 required. - [CFR 90.7 - Definitions]. 1831 Authors' Addresses 1833 Alexandre Petrescu 1834 CEA, LIST 1835 CEA Saclay 1836 Gif-sur-Yvette , Ile-de-France 91190 1837 France 1839 Phone: +33169089223 1840 Email: Alexandre.Petrescu@cea.fr 1842 Nabil Benamar 1843 Moulay Ismail University 1844 Morocco 1846 Phone: +212670832236 1847 Email: n.benamar@est.umi.ac.ma 1848 Jerome Haerri 1849 Eurecom 1850 Sophia-Antipolis 06904 1851 France 1853 Phone: +33493008134 1854 Email: Jerome.Haerri@eurecom.fr 1856 Jong-Hyouk Lee 1857 Sangmyung University 1858 31, Sangmyeongdae-gil, Dongnam-gu 1859 Cheonan 31066 1860 Republic of Korea 1862 Email: jonghyouk@smu.ac.kr 1864 Thierry Ernst 1865 YoGoKo 1866 France 1868 Email: thierry.ernst@yogoko.fr