idnits 2.17.1 draft-ietf-ipwave-ipv6-over-80211ocb-31.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 (November 19, 2018) is 1979 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 Summary: 5 errors (**), 0 flaws (~~), 2 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: May 23, 2019 Moulay Ismail University 6 J. Haerri 7 Eurecom 8 J. Lee 9 Sangmyung University 10 T. Ernst 11 YoGoKo 12 November 19, 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-31 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 May 23, 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 . . . . . . . . . . . . . . . . . . . . 5 68 4.1. Pseudonym Handling . . . . . . . . . . . . . . . . . . . 5 69 4.2. Maximum Transmission Unit (MTU) . . . . . . . . . . . . . 5 70 4.3. Frame Format . . . . . . . . . . . . . . . . . . . . . . 5 71 4.3.1. Ethernet Adaptation Layer . . . . . . . . . . . . . . 6 72 4.4. Link-Local Addresses . . . . . . . . . . . . . . . . . . 7 73 4.5. Address Mapping . . . . . . . . . . . . . . . . . . . . . 7 74 4.5.1. Address Mapping -- Unicast . . . . . . . . . . . . . 7 75 4.5.2. Address Mapping -- Multicast . . . . . . . . . . . . 8 76 4.6. Stateless Autoconfiguration . . . . . . . . . . . . . . . 8 77 4.7. Subnet Structure . . . . . . . . . . . . . . . . . . . . 9 78 5. Security Considerations . . . . . . . . . . . . . . . . . . . 10 79 5.1. Privacy Considerations . . . . . . . . . . . . . . . . . 11 80 5.2. MAC Address and Interface ID Generation . . . . . . . . . 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 . . . . . . . . . . . . . . . . . . . . . . 26 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 . . . . . . . . . . . . . 33 96 H.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . 34 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 4.3.1. 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 handover behaviour. For security and privacy recommendations see 126 Section 5 and Section 4.6. The subnet structure is described in 127 Section 4.7. The handover behaviour on OCB links is not described 128 in this document. 130 The Security Considerations section describes security and privacy 131 aspects of 802.11-OCB. 133 In the published literature, many documents describe aspects and 134 problems related to running IPv6 over 802.11-OCB: 135 [I-D.ietf-ipwave-vehicular-networking-survey]. 137 2. Terminology 139 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 140 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 141 document are to be interpreted as described in RFC 2119 [RFC2119]. 143 IP-OBU (Internet Protocol On-Board Unit): an IP-OBU is a computer 144 situated in a vehicle such as an automobile, bicycle, or similar. It 145 has at least one IP interface that runs in mode OCB of 802.11, and 146 that has an "OBU" transceiver. See the definition of the term "OBU" 147 in section Appendix I. 149 IP-RSU (IP Road-Side Unit): an IP-RSU is situated along the road. It 150 has at least two distinct IP-enabled interfaces; the wireless PHY/MAC 151 layer of at least one of its IP-enabled interfaces is configured to 152 operate in 802.11-OCB mode. An IP-RSU communicates with the IP-OBU 153 in the vehicle over 802.11 wireless link operating in OCB mode. An 154 IP-RSU is similar to an Access Network Router (ANR) defined in 155 [RFC3753], and a Wireless Termination Point (WTP) defined in 156 [RFC5415]. 158 OCB (outside the context of a basic service set - BSS): A mode of 159 operation in which a STA is not a member of a BSS and does not 160 utilize IEEE Std 802.11 authentication, association, or data 161 confidentiality. 163 802.11-OCB: mode specified in IEEE Std 802.11-2016 when the MIB 164 attribute dot11OCBActivited is true. Note: compliance with standards 165 and regulations set in different countries when using the 5.9GHz 166 frequency band is required. 168 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 170 The IEEE 802.11-OCB Networks are used for vehicular communications, 171 as 'Wireless Access in Vehicular Environments'. The IP communication 172 scenarios for these environments have been described in several 173 documents; in particular, we refer the reader to 174 [I-D.ietf-ipwave-vehicular-networking-survey], that lists some 175 scenarios and requirements for IP in Intelligent Transportation 176 Systems. 178 The link model is the following: STA --- 802.11-OCB --- STA. In 179 vehicular networks, STAs can be IP-RSUs and/or IP-OBUs. While 180 802.11-OCB is clearly specified, and the use of IPv6 over such link 181 is not radically new, the operating environment (vehicular networks) 182 brings in new perspectives. 184 The mechanisms for forming and terminating, discovering, peering and 185 mobility management for 802.11-OCB links are not described in this 186 document. 188 4. IPv6 over 802.11-OCB 190 4.1. Pseudonym Handling 192 The demand for privacy protection of vehicles' and drivers' 193 identities, which could be granted by using a pseudonym or alias 194 identity at the same time, may hamper the required confidentiality of 195 messages and trust between participants - especially in safety 196 critical vehicular communication. 198 o Particular challenges arise when the pseudonymization mechanism 199 used relies on (randomized) re-addressing. 201 o A proper pseudonymization tool operated by a trusted third party 202 may be needed to ensure both aspects concurrently. 204 o This is discussed in Section 4.6 and Section 5. 206 o Pseudonymity is also discussed in 207 [I-D.ietf-ipwave-vehicular-networking-survey] in sections 4.2.4 208 and 5.1.2. 210 4.2. Maximum Transmission Unit (MTU) 212 The default MTU for IP packets on 802.11-OCB MUST be 1500 octets. It 213 is the same value as IPv6 packets on Ethernet links, as specified in 214 [RFC2464]. This value of the MTU respects the recommendation that 215 every link on the Internet must have a minimum MTU of 1280 octets 216 (stated in [RFC8200], and the recommendations therein, especially 217 with respect to fragmentation). 219 4.3. Frame Format 221 IP packets MUST be transmitted over 802.11-OCB media as QoS Data 222 frames whose format is specified in IEEE Std 802.11. 224 The IPv6 packet transmitted on 802.11-OCB MUST be immediately 225 preceded by a Logical Link Control (LLC) header and an 802.11 header. 226 In the LLC header, and in accordance with the EtherType Protocol 227 Discrimination (EPD, see Appendix E), the value of the Type field 228 MUST be set to 0x86DD (IPv6). In the 802.11 header, the value of the 229 Subtype sub-field in the Frame Control field MUST be set to 8 (i.e. 230 'QoS Data'); the value of the Traffic Identifier (TID) sub-field of 231 the QoS Control field of the 802.11 header MUST be set to binary 001 232 (i.e. User Priority 'Background', QoS Access Category 'AC_BK'). 234 To simplify the Application Programming Interface (API) between the 235 operating system and the 802.11-OCB media, device drivers MAY 236 implement an Ethernet Adaptation Layer that translates Ethernet II 237 frames to the 802.11 format and vice versa. An Ethernet Adaptation 238 Layer is described in Section 4.3.1. 240 4.3.1. Ethernet Adaptation Layer 242 An 'adaptation' layer is inserted between a MAC layer and the 243 Networking layer. This is used to transform some parameters between 244 their form expected by the IP stack and the form provided by the MAC 245 layer. 247 An Ethernet Adaptation Layer makes an 802.11 MAC look to IP 248 Networking layer as a more traditional Ethernet layer. At reception, 249 this layer takes as input the IEEE 802.11 header and the Logical-Link 250 Layer Control Header and produces an Ethernet II Header. At sending, 251 the reverse operation is performed. 253 The operation of the Ethernet Adaptation Layer is depicted by the 254 double arrow in Figure 1. 256 +------------------+------------+-------------+---------+-----------+ 257 | 802.11 header | LLC Header | IPv6 Header | Payload |.11 Trailer| 258 +------------------+------------+-------------+---------+-----------+ 259 \ / \ / 260 --------------------------- -------- 261 \---------------------------------------------/ 262 ^ 263 | 264 802.11-to-Ethernet Adaptation Layer 265 | 266 v 267 +---------------------+-------------+---------+ 268 | Ethernet II Header | IPv6 Header | Payload | 269 +---------------------+-------------+---------+ 271 Figure 1: Operation of the Ethernet Adaptation Layer 273 The Receiver and Transmitter Address fields in the 802.11 header MUST 274 contain the same values as the Destination and the Source Address 275 fields in the Ethernet II Header, respectively. The value of the 276 Type field in the LLC Header MUST be the same as the value of the 277 Type field in the Ethernet II Header. That value MUST be set to 278 0x86DD (IPv6). 280 The ".11 Trailer" contains solely a 4-byte Frame Check Sequence. 282 The placement of IPv6 networking layer on Ethernet Adaptation Layer 283 is illustrated in Figure 2. 285 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 286 | IPv6 | 287 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 288 | Ethernet Adaptation Layer | 289 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 290 | 802.11 MAC | 291 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 292 | 802.11 PHY | 293 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 295 Figure 2: Ethernet Adaptation Layer stacked with other layers 297 (in the above figure, a 802.11 profile is represented; this is used 298 also for 802.11-OCB profile.) 300 4.4. Link-Local Addresses 302 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 303 MAY be assigned to an 802.11-OCB interface. Among these types of 304 addresses only the IPv6 link-local addresses MAY be formed using an 305 EUI-64 identifier. 307 If the IPv6 link-local address is formed using an EUI-64 identifier, 308 then the mechanism of forming that address is the same mechanism as 309 used to form an IPv6 link-local address on Ethernet links. This 310 mechanism is described in section 5 of [RFC2464]. 312 For privacy, the link-local address MAY be formed according to the 313 mechanisms described in Section 5.2. 315 4.5. Address Mapping 317 Unicast and multicast address mapping MUST follow the procedures 318 specified for Ethernet interfaces in sections 6 and 7 of [RFC2464]. 320 4.5.1. Address Mapping -- Unicast 322 The procedure for mapping IPv6 unicast addresses into Ethernet link- 323 layer addresses is described in [RFC4861]. 325 4.5.2. Address Mapping -- Multicast 327 The multicast address mapping is performed according to the method 328 specified in section 7 of [RFC2464]. The meaning of the value "3333" 329 mentioned in that section 7 of [RFC2464] is defined in section 2.3.1 330 of [RFC7042]. 332 Transmitting IPv6 packets to multicast destinations over 802.11 links 333 proved to have some performance issues 334 [I-D.perkins-intarea-multicast-ieee802]. These issues may be 335 exacerbated in OCB mode. Solutions for these problems should 336 consider the OCB mode of operation. 338 4.6. Stateless Autoconfiguration 340 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 341 MAY be assigned to an 802.11-OCB interface. This section describes 342 the formation of Interface Identifiers for IPv6 addresses of type 343 'Global' or 'Unique Local'. For Interface Identifiers for IPv6 344 address of type 'Link-Local' see Section 4.4. 346 The Interface Identifier for an 802.11-OCB interface is formed using 347 the same rules as the Interface Identifier for an Ethernet interface; 348 the RECOMMENDED method for forming stable Interface Identifiers 349 (IIDs) is described in [RFC8064]. The method of forming IIDs 350 described in section 4 of [RFC2464] MAY be used during transition 351 time. 353 The bits in the Interface Identifier have no generic meaning and the 354 identifier should be treated as an opaque value. The bits 355 'Universal' and 'Group' in the identifier of an 802.11-OCB interface 356 are significant, as this is an IEEE link-layer address. The details 357 of this significance are described in [RFC7136]. If semantically 358 opaque Interface Identifiers are needed, a potential method for 359 generating semantically opaque Interface Identifiers with IPv6 360 Stateless Address Autoconfiguration is given in [RFC7217]. 362 Semantically opaque Interface Identifiers, instead of meaningful 363 Interface Identifiers derived from a valid and meaningful MAC address 364 ([RFC2464], section 4), MAY be needed in order to avoid certain 365 privacy risks. 367 A valid MAC address includes a unique identifier pointing to a 368 company together with its postal address, and a unique number within 369 that company MAC space (see the oui.txt file). The calculation 370 operation of the MAC address back from a given meaningful Interface 371 Identifier is straightforward ([RFC2464], section 4). The Interface 372 Identifier is part of an IPv6 address that is stored in IPv6 packets. 374 The IPv6 packets can be captured in the Internet easily. For these 375 reasons, an attacker may realize many attacks on privacy. One such 376 attack on 802.11-OCB is to capture, store and correlate Company ID 377 information of many cars in public areas (e.g. listen for Router 378 Advertisements, or other IPv6 application data packets, and record 379 the value of the source address in these packets). Further 380 correlation of this information with other data captured by other 381 means, or other visual information (car color, others) MAY constitute 382 privacy risks. 384 In order to avoid these risks, opaque Interface Identifiers MAY be 385 formed according to rules described in [RFC7217]. These opaque 386 Interface Identifiers are formed starting from identifiers different 387 than the MAC addresses, and from cryptographically strong material. 388 Thus, privacy sensitive information is absent from Interface IDs, and 389 it is impossible to calculate the initial value from which the 390 Interface ID was calculated. 392 Some applications that use IPv6 packets on 802.11-OCB links (among 393 other link types) may benefit from IPv6 addresses whose Interface 394 Identifiers don't change too often. It is RECOMMENDED to use the 395 mechanisms described in RFC 7217 to permit the use of Stable 396 Interface Identifiers that do not change within one subnet prefix. A 397 possible source for the Net-Iface Parameter is a virtual interface 398 name, or logical interface name, that is decided by a local 399 administrator. 401 The way Interface Identifiers are used MAY involve risks to privacy, 402 as described in Section 5.1. 404 4.7. Subnet Structure 406 A subnet is formed by the external 802.11-OCB interfaces of vehicles 407 that are in close range (not by their in-vehicle interfaces). This 408 subnet MUST use at least the link-local prefix fe80::/10 and the 409 interfaces MUST be assigned IPv6 addresses of type link-local. 411 The structure of this subnet is ephemeral, in that it is strongly 412 influenced by the mobility of vehicles: the 802.11 hidden node 413 effects appear; the 802.11 networks in OCB mode may be considered as 414 'ad-hoc' networks with an addressing model as described in [RFC5889]. 415 On another hand, the structure of the internal subnets in each car is 416 relatively stable. 418 As recommended in [RFC5889], when the timing requirements are very 419 strict (e.g. fast drive through IP-RSU coverage), no on-link subnet 420 prefix should be configured on an 802.11-OCB interface. In such 421 cases, the exclusive use of IPv6 link-local addresses is RECOMMENDED. 423 Additionally, even if the timing requirements are not very strict 424 (e.g. the moving subnet formed by two following vehicles is stable, a 425 fixed IP-RSU is absent), the subnet is disconnected from the Internet 426 (a default route is absent), and the addressing peers are equally 427 qualified (impossible to determine that some vehicle owns and 428 distributes addresses to others) the use of link-local addresses is 429 RECOMMENDED. 431 The Neighbor Discovery protocol (ND) [RFC4861] is used over 432 802.11-OCB links. Due to lack of link-layer acknowledgements in 433 802.11-OCB for both unicast and multicast, we can expect higher 434 unicast loss than for 802.11 BSS. The ND retransmissions are 435 supposed to handle loss of unicast and/or multicast just as it does 436 for other link types. 438 Protocols like Mobile IPv6 [RFC6275] and DNAv6 [RFC6059], which 439 depend on timely movement detection, might need additional tuning 440 work to handle the lack of link-layer notifications during handover. 441 This is for further study. 443 5. Security Considerations 445 Any security mechanism at the IP layer or above that may be carried 446 out for the general case of IPv6 may also be carried out for IPv6 447 operating over 802.11-OCB. 449 The OCB operation is stripped off of all existing 802.11 link-layer 450 security mechanisms. There is no encryption applied below the 451 network layer running on 802.11-OCB. At application layer, the IEEE 452 1609.2 document [IEEE-1609.2] does provide security services for 453 certain applications to use; application-layer mechanisms are out-of- 454 scope of this document. On another hand, a security mechanism 455 provided at networking layer, such as IPsec [RFC4301], may provide 456 data security protection to a wider range of applications. 458 802.11-OCB does not provide any cryptographic protection, because it 459 operates outside the context of a BSS (no Association Request/ 460 Response, no Challenge messages). Any attacker can therefore just 461 sit in the near range of vehicles, sniff the network (just set the 462 interface card's frequency to the proper range) and perform attacks 463 without needing to physically break any wall. Such a link is less 464 protected than commonly used links (wired link or protected 802.11). 466 The potential attack vectors are: MAC address spoofing, IP address 467 and session hijacking, and privacy violation Section 5.1. 469 Within the IPsec Security Architecture [RFC4301], the IPsec AH and 470 ESP headers [RFC4302] and [RFC4303] respectively, its multicast 471 extensions [RFC5374], HTTPS [RFC2818] and SeND [RFC3971] protocols 472 can be used to protect communications. Further, the assistance of 473 proper Public Key Infrastructure (PKI) protocols [RFC4210] is 474 necessary to establish credentials. More IETF protocols are 475 available in the toolbox of the IP security protocol designer. 476 Certain ETSI protocols related to security protocols in Intelligent 477 Transportation Systems are described in [ETSI-sec-archi]. 479 5.1. Privacy Considerations 481 As with all Ethernet and 802.11 interface identifiers ([RFC7721]), 482 the identifier of an 802.11-OCB interface may involve privacy, MAC 483 address spoofing and IP address hijacking risks. A vehicle embarking 484 an IP-OBU whose egress interface is 802.11-OCB may expose itself to 485 eavesdropping and subsequent correlation of data; this may reveal 486 data considered private by the vehicle owner; there is a risk of 487 being tracked. In outdoors public environments, where vehicles 488 typically circulate, the privacy risks are more important than in 489 indoors settings. It is highly likely that attacker sniffers are 490 deployed along routes which listen for IEEE frames, including IP 491 packets, of vehicles passing by. For this reason, in the 802.11-OCB 492 deployments, there is a strong necessity to use protection tools such 493 as dynamically changing MAC addresses Section 5.2, semantically 494 opaque Interface Identifiers and stable Interface Identifiers 495 Section 4.6. This may help mitigate privacy risks to a certain 496 level. 498 5.2. MAC Address and Interface ID Generation 500 In 802.11-OCB networks, the MAC addresses MAY change during well 501 defined renumbering events. In the moment the MAC address is changed 502 on an 802.11-OCB interface all the Interface Identifiers of IPv6 503 addresses assigned to that interface MUST change. 505 The policy dictating when the MAC address is changed on the 506 802.11-OCB interface is to-be-determined. For more information on 507 the motivation of this policy please refer to the privacy discussion 508 in Appendix C. 510 A 'randomized' MAC address has the following characteristics: 512 o Bit "Local/Global" set to "locally admninistered". 514 o Bit "Unicast/Multicast" set to "Unicast". 516 o The 46 remaining bits are set to a random value, using a random 517 number generator that meets the requirements of [RFC4086]. 519 To meet the randomization requirements for the 46 remaining bits, a 520 hash function may be used. For example, the SHA256 hash function may 521 be used with input a 256 bit local secret, the 'nominal' MAC Address 522 of the interface, and a representation of the date and time of the 523 renumbering event. 525 A randomized Interface ID has the same characteristics of a 526 randomized MAC address, except the length in bits. A MAC address 527 SHOULD be of length 48 decimal. An Interface ID SHOULD be of length 528 64 decimal for all types of IPv6 addresses. In the particular case 529 of IPv6 link-local addresses, the length of the Interface ID MAY be 530 118 decimal. 532 6. IANA Considerations 534 No request to IANA. 536 7. Contributors 538 Christian Huitema, Tony Li. 540 Romain Kuntz contributed extensively about IPv6 handovers between 541 links running outside the context of a BSS (802.11-OCB links). 543 Tim Leinmueller contributed the idea of the use of IPv6 over 544 802.11-OCB for distribution of certificates. 546 Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey 547 Voronov provided significant feedback on the experience of using IP 548 messages over 802.11-OCB in initial trials. 550 Michelle Wetterwald contributed extensively the MTU discussion, 551 offered the ETSI ITS perspective, and reviewed other parts of the 552 document. 554 8. Acknowledgements 556 The authors would like to thank Witold Klaudel, Ryuji Wakikawa, 557 Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan 558 Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray 559 Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, 560 Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne, 561 Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark, 562 Bob Moskowitz, Andrew Dryden, Georg Mayer, Dorothy Stanley, Sandra 563 Cespedes, Mariano Falcitelli, Sri Gundavelli, Abdussalam Baryun, 564 Margaret Cullen, Erik Kline, Carlos Jesus Bernardos Cano, Ronald in 565 't Velt, Katrin Sjoberg, Roland Bless, Tijink Jasja, Kevin Smith, 566 Brian Carpenter, Julian Reschke, Mikael Abrahamsson, Dirk von Hugo, 567 Lorenzo Colitti and William Whyte. Their valuable comments clarified 568 particular issues and generally helped to improve the document. 570 Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB 571 drivers for linux and described how. 573 For the multicast discussion, the authors would like to thank Owen 574 DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and 575 participants to discussions in network working groups. 577 The authors would like to thank participants to the Birds-of- 578 a-Feather "Intelligent Transportation Systems" meetings held at IETF 579 in 2016. 581 Human Rights Protocol Considerations review by Amelia Andersdotter. 583 9. References 585 9.1. Normative References 587 [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission 588 of IP datagrams over IEEE 802 networks", STD 43, RFC 1042, 589 DOI 10.17487/RFC1042, February 1988, 590 . 592 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 593 Requirement Levels", BCP 14, RFC 2119, 594 DOI 10.17487/RFC2119, March 1997, 595 . 597 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 598 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 599 . 601 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 602 DOI 10.17487/RFC2818, May 2000, 603 . 605 [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related 606 Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, 607 . 609 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 610 "SEcure Neighbor Discovery (SEND)", RFC 3971, 611 DOI 10.17487/RFC3971, March 2005, 612 . 614 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 615 "Randomness Requirements for Security", BCP 106, RFC 4086, 616 DOI 10.17487/RFC4086, June 2005, 617 . 619 [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast 620 Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005, 621 . 623 [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, 624 "Internet X.509 Public Key Infrastructure Certificate 625 Management Protocol (CMP)", RFC 4210, 626 DOI 10.17487/RFC4210, September 2005, 627 . 629 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 630 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 631 2006, . 633 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 634 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 635 December 2005, . 637 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 638 DOI 10.17487/RFC4302, December 2005, 639 . 641 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 642 RFC 4303, DOI 10.17487/RFC4303, December 2005, 643 . 645 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 646 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 647 DOI 10.17487/RFC4861, September 2007, 648 . 650 [RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast 651 Extensions to the Security Architecture for the Internet 652 Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008, 653 . 655 [RFC5415] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, 656 Ed., "Control And Provisioning of Wireless Access Points 657 (CAPWAP) Protocol Specification", RFC 5415, 658 DOI 10.17487/RFC5415, March 2009, 659 . 661 [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing 662 Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889, 663 September 2010, . 665 [RFC6059] Krishnan, S. and G. Daley, "Simple Procedures for 666 Detecting Network Attachment in IPv6", RFC 6059, 667 DOI 10.17487/RFC6059, November 2010, 668 . 670 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 671 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 672 2011, . 674 [RFC7042] Eastlake 3rd, D. and J. Abley, "IANA Considerations and 675 IETF Protocol and Documentation Usage for IEEE 802 676 Parameters", BCP 141, RFC 7042, DOI 10.17487/RFC7042, 677 October 2013, . 679 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 680 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 681 February 2014, . 683 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 684 Interface Identifiers with IPv6 Stateless Address 685 Autoconfiguration (SLAAC)", RFC 7217, 686 DOI 10.17487/RFC7217, April 2014, 687 . 689 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 690 Considerations for IPv6 Address Generation Mechanisms", 691 RFC 7721, DOI 10.17487/RFC7721, March 2016, 692 . 694 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 695 "Recommendation on Stable IPv6 Interface Identifiers", 696 RFC 8064, DOI 10.17487/RFC8064, February 2017, 697 . 699 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 700 (IPv6) Specification", STD 86, RFC 8200, 701 DOI 10.17487/RFC8200, July 2017, 702 . 704 9.2. Informative References 706 [ETSI-sec-archi] 707 "ETSI TS 102 940 V1.2.1 (2016-11), ETSI Technical 708 Specification, Intelligent Transport Systems (ITS); 709 Security; ITS communications security architecture and 710 security management, November 2016. Downloaded on 711 September 9th, 2017, freely available from ETSI website at 712 URL http://www.etsi.org/deliver/ 713 etsi_ts/102900_102999/102940/01.02.01_60/ 714 ts_102940v010201p.pdf". 716 [I-D.hinden-6man-rfc2464bis] 717 Crawford, M. and R. Hinden, "Transmission of IPv6 Packets 718 over Ethernet Networks", draft-hinden-6man-rfc2464bis-02 719 (work in progress), March 2017. 721 [I-D.ietf-ipwave-vehicular-networking-survey] 722 Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M. 723 Wetterwald, "Survey on IP-based Vehicular Networking for 724 Intelligent Transportation Systems", draft-ietf-ipwave- 725 vehicular-networking-survey-00 (work in progress), July 726 2017. 728 [I-D.perkins-intarea-multicast-ieee802] 729 Perkins, C., Stanley, D., Kumari, W., and J. Zuniga, 730 "Multicast Considerations over IEEE 802 Wireless Media", 731 draft-perkins-intarea-multicast-ieee802-03 (work in 732 progress), July 2017. 734 [IEEE-1609.2] 735 "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access 736 in Vehicular Environments (WAVE) -- Security Services for 737 Applications and Management Messages. Example URL 738 http://ieeexplore.ieee.org/document/7426684/ accessed on 739 August 17th, 2017.". 741 [IEEE-1609.3] 742 "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access 743 in Vehicular Environments (WAVE) -- Networking Services. 744 Example URL http://ieeexplore.ieee.org/document/7458115/ 745 accessed on August 17th, 2017.". 747 [IEEE-1609.4] 748 "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access 749 in Vehicular Environments (WAVE) -- Multi-Channel 750 Operation. Example URL 751 http://ieeexplore.ieee.org/document/7435228/ accessed on 752 August 17th, 2017.". 754 [IEEE-802.11-2016] 755 "IEEE Standard 802.11-2016 - IEEE Standard for Information 756 Technology - Telecommunications and information exchange 757 between systems Local and metropolitan area networks - 758 Specific requirements - Part 11: Wireless LAN Medium 759 Access Control (MAC) and Physical Layer (PHY) 760 Specifications. Status - Active Standard. Description 761 retrieved freely on September 12th, 2017, at URL 762 https://standards.ieee.org/findstds/ 763 standard/802.11-2016.html". 765 [IEEE-802.11p-2010] 766 "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information 767 Technology - Telecommunications and information exchange 768 between systems - Local and metropolitan area networks - 769 Specific requirements, Part 11: Wireless LAN Medium Access 770 Control (MAC) and Physical Layer (PHY) Specifications, 771 Amendment 6: Wireless Access in Vehicular Environments; 772 document freely available at URL 773 http://standards.ieee.org/getieee802/ 774 download/802.11p-2010.pdf retrieved on September 20th, 775 2013.". 777 Appendix A. ChangeLog 779 The changes are listed in reverse chronological order, most recent 780 changes appearing at the top of the list. 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 798 -28: 800 o Created a new section 'Pseudonym Handling'. 802 o removed the 'Vehicle ID' appendix. 804 o improved the address generation from random MAC address. 806 o shortened Term IP-RSU definition. 808 o removed refs to two detail Clauses in IEEE documents, kept just 809 these latter. 811 -27: part 1 of addressing Human Rights review from IRTF. Removed 812 appendices F.2 and F.3. Shortened definition of IP-RSU. Removed 813 reference to 1609.4. A few other small changes, see diff. 815 -26: moved text from SLAAC section and from Design Considerations 816 appendix about privacy into a new Privacy Condiderations subsection 817 of the Security section; reformulated the SLAAC and IID sections to 818 stress only LLs can use EUI-64; removed the "GeoIP" wireshark 819 explanation; reformulated SLAAC and LL sections; added brief mention 820 of need of use LLs; clarified text about MAC address changes; dropped 821 pseudonym discussion; changed title of section describing examples of 822 packet formats. 824 -25: added a reference to 'IEEE Management Information Base', instead 825 of just 'Management Information Base'; added ref to further 826 appendices in the introductory phrases; improved text for IID 827 formation for SLAAC, inserting recommendation for RFC8064 before 828 RFC2464. 830 From draft-ietf-ipwave-ipv6-over-80211ocb-23 to draft-ietf-ipwave- 831 ipv6-over-80211ocb-24 833 o Nit: wrote "IPWAVE Working Group" on the front page, instead of 834 "Network Working Group". 836 o Addressed the comments on 6MAN: replaced a sentence about ND 837 problem with "is used over 802.11-OCB". 839 From draft-ietf-ipwave-ipv6-over-80211ocb-22 to draft-ietf-ipwave- 840 ipv6-over-80211ocb-23 842 o No content modifications, but check the entire draft chain on 843 IPv6-only: xml2rfc, submission on tools.ietf.org and datatracker. 845 From draft-ietf-ipwave-ipv6-over-80211ocb-21 to draft-ietf-ipwave- 846 ipv6-over-80211ocb-22 848 o Corrected typo, use dash in "802.11-OCB" instead of space. 850 o Improved the Frame Format section: MUST use QoSData, specify the 851 values within; clarified the Ethernet Adaptation Layer text. 853 From draft-ietf-ipwave-ipv6-over-80211ocb-20 to draft-ietf-ipwave- 854 ipv6-over-80211ocb-21 856 o Corrected a few nits and added names in Acknowledgments section. 858 o Removed unused reference to old Internet Draft tsvwg about QoS. 860 From draft-ietf-ipwave-ipv6-over-80211ocb-19 to draft-ietf-ipwave- 861 ipv6-over-80211ocb-20 863 o Reduced the definition of term "802.11-OCB". 865 o Left out of this specification which 802.11 header to use to 866 transmit IP packets in OCB mode (QoS Data header, Data header, or 867 any other). 869 o Added 'MUST' use an Ethernet Adaptation Layer, instead of 'is 870 using' an Ethernet Adaptation Layer. 872 From draft-ietf-ipwave-ipv6-over-80211ocb-18 to draft-ietf-ipwave- 873 ipv6-over-80211ocb-19 875 o Removed the text about fragmentation. 877 o Removed the mentioning of WSMP and GeoNetworking. 879 o Removed the explanation of the binary representation of the 880 EtherType. 882 o Rendered normative the paragraph about unicast and multicast 883 address mapping. 885 o Removed paragraph about addressing model, subnet structure and 886 easiness of using LLs. 888 o Clarified the Type/Subtype field in the 802.11 Header. 890 o Used RECOMMENDED instead of recommended, for the stable interface 891 identifiers. 893 From draft-ietf-ipwave-ipv6-over-80211ocb-17 to draft-ietf-ipwave- 894 ipv6-over-80211ocb-18 896 o Improved the MTU and fragmentation paragraph. 898 From draft-ietf-ipwave-ipv6-over-80211ocb-16 to draft-ietf-ipwave- 899 ipv6-over-80211ocb-17 901 o Susbtituted "MUST be increased" to "is increased" in the MTU 902 section, about fragmentation. 904 From draft-ietf-ipwave-ipv6-over-80211ocb-15 to draft-ietf-ipwave- 905 ipv6-over-80211ocb-16 907 o Removed the definition of the 'WiFi' term and its occurences. 908 Clarified a phrase that used it in Appendix C "Aspects introduced 909 by the OCB mode to 802.11". 911 o Added more normative words: MUST be 0x86DD, MUST fragment if size 912 larger than MTU, Sequence number in 802.11 Data header MUST be 913 increased. 915 From draft-ietf-ipwave-ipv6-over-80211ocb-14 to draft-ietf-ipwave- 916 ipv6-over-80211ocb-15 918 o Added normative term MUST in two places in section "Ethernet 919 Adaptation Layer". 921 From draft-ietf-ipwave-ipv6-over-80211ocb-13 to draft-ietf-ipwave- 922 ipv6-over-80211ocb-14 924 o Created a new Appendix titled "Extra Terminology" that contains 925 terms DSRC, DSRCS, OBU, RSU as defined outside IETF. Some of them 926 are used in the main Terminology section. 928 o Added two paragraphs explaining that ND and Mobile IPv6 have 929 problems working over 802.11-OCB, yet their adaptations is not 930 specified in this document. 932 From draft-ietf-ipwave-ipv6-over-80211ocb-12 to draft-ietf-ipwave- 933 ipv6-over-80211ocb-13 935 o Substituted "IP-OBU" for "OBRU", and "IP-RSU" for "RSRU" 936 throughout and improved OBU-related definitions in the Terminology 937 section. 939 From draft-ietf-ipwave-ipv6-over-80211ocb-11 to draft-ietf-ipwave- 940 ipv6-over-80211ocb-12 942 o Improved the appendix about "MAC Address Generation" by expressing 943 the technique to be an optional suggestion, not a mandatory 944 mechanism. 946 From draft-ietf-ipwave-ipv6-over-80211ocb-10 to draft-ietf-ipwave- 947 ipv6-over-80211ocb-11 949 o Shortened the paragraph on forming/terminating 802.11-OCB links. 951 o Moved the draft tsvwg-ieee-802-11 to Informative References. 953 From draft-ietf-ipwave-ipv6-over-80211ocb-09 to draft-ietf-ipwave- 954 ipv6-over-80211ocb-10 956 o Removed text requesting a new Group ID for multicast for OCB. 958 o Added a clarification of the meaning of value "3333" in the 959 section Address Mapping -- Multicast. 961 o Added note clarifying that in Europe the regional authority is not 962 ETSI, but "ECC/CEPT based on ENs from ETSI". 964 o Added note stating that the manner in which two STAtions set their 965 communication channel is not described in this document. 967 o Added a time qualifier to state that the "each node is represented 968 uniquely at a certain point in time." 970 o Removed text "This section may need to be moved" (the "Reliability 971 Requirements" section). This section stays there at this time. 973 o In the term definition "802.11-OCB" added a note stating that "any 974 implementation should comply with standards and regulations set in 975 the different countries for using that frequency band." 977 o In the RSU term definition, added a sentence explaining the 978 difference between RSU and RSRU: in terms of number of interfaces 979 and IP forwarding. 981 o Replaced "with at least two IP interfaces" with "with at least two 982 real or virtual IP interfaces". 984 o Added a term in the Terminology for "OBU". However the definition 985 is left empty, as this term is defined outside IETF. 987 o Added a clarification that it is an OBU or an OBRU in this phrase 988 "A vehicle embarking an OBU or an OBRU". 990 o Checked the entire document for a consistent use of terms OBU and 991 OBRU. 993 o Added note saying that "'p' is a letter identifying the 994 Ammendment". 996 o Substituted lower case for capitals SHALL or MUST in the 997 Appendices. 999 o Added reference to RFC7042, helpful in the 3333 explanation. 1000 Removed reference to individual submission draft-petrescu-its- 1001 scenario-reqs and added reference to draft-ietf-ipwave-vehicular- 1002 networking-survey. 1004 o Added figure captions, figure numbers, and references to figure 1005 numbers instead of 'below'. Replaced "section Section" with 1006 "section" throughout. 1008 o Minor typographical errors. 1010 From draft-ietf-ipwave-ipv6-over-80211ocb-08 to draft-ietf-ipwave- 1011 ipv6-over-80211ocb-09 1013 o Significantly shortened the Address Mapping sections, by text 1014 copied from RFC2464, and rather referring to it. 1016 o Moved the EPD description to an Appendix on its own. 1018 o Shortened the Introduction and the Abstract. 1020 o Moved the tutorial section of OCB mode introduced to .11, into an 1021 appendix. 1023 o Removed the statement that suggests that for routing purposes a 1024 prefix exchange mechanism could be needed. 1026 o Removed refs to RFC3963, RFC4429 and RFC6775; these are about ND, 1027 MIP/NEMO and oDAD; they were referred in the handover discussion 1028 section, which is out. 1030 o Updated a reference from individual submission to now a WG item in 1031 IPWAVE: the survey document. 1033 o Added term definition for WiFi. 1035 o Updated the authorship and expanded the Contributors section. 1037 o Corrected typographical errors. 1039 From draft-ietf-ipwave-ipv6-over-80211ocb-07 to draft-ietf-ipwave- 1040 ipv6-over-80211ocb-08 1041 o Removed the per-channel IPv6 prohibition text. 1043 o Corrected typographical errors. 1045 From draft-ietf-ipwave-ipv6-over-80211ocb-06 to draft-ietf-ipwave- 1046 ipv6-over-80211ocb-07 1048 o Added new terms: OBRU and RSRU ('R' for Router). Refined the 1049 existing terms RSU and OBU, which are no longer used throughout 1050 the document. 1052 o Improved definition of term "802.11-OCB". 1054 o Clarified that OCB does not "strip" security, but that the 1055 operation in OCB mode is "stripped off of all .11 security". 1057 o Clarified that theoretical OCB bandwidth speed is 54mbits, but 1058 that a commonly observed bandwidth in IP-over-OCB is 12mbit/s. 1060 o Corrected typographical errors, and improved some phrasing. 1062 From draft-ietf-ipwave-ipv6-over-80211ocb-05 to draft-ietf-ipwave- 1063 ipv6-over-80211ocb-06 1065 o Updated references of 802.11-OCB document from -2012 to the IEEE 1066 802.11-2016. 1068 o In the LL address section, and in SLAAC section, added references 1069 to 7217 opaque IIDs and 8064 stable IIDs. 1071 From draft-ietf-ipwave-ipv6-over-80211ocb-04 to draft-ietf-ipwave- 1072 ipv6-over-80211ocb-05 1074 o Lengthened the title and cleanded the abstract. 1076 o Added text suggesting LLs may be easy to use on OCB, rather than 1077 GUAs based on received prefix. 1079 o Added the risks of spoofing and hijacking. 1081 o Removed the text speculation on adoption of the TSA message. 1083 o Clarified that the ND protocol is used. 1085 o Clarified what it means "No association needed". 1087 o Added some text about how two STAs discover each other. 1089 o Added mention of external (OCB) and internal network (stable), in 1090 the subnet structure section. 1092 o Added phrase explaining that both .11 Data and .11 QoS Data 1093 headers are currently being used, and may be used in the future. 1095 o Moved the packet capture example into an Appendix Implementation 1096 Status. 1098 o Suggested moving the reliability requirements appendix out into 1099 another document. 1101 o Added a IANA Consiserations section, with content, requesting for 1102 a new multicast group "all OCB interfaces". 1104 o Added new OBU term, improved the RSU term definition, removed the 1105 ETTC term, replaced more occurences of 802.11p, 802.11-OCB with 1106 802.11-OCB. 1108 o References: 1110 * Added an informational reference to ETSI's IPv6-over- 1111 GeoNetworking. 1113 * Added more references to IETF and ETSI security protocols. 1115 * Updated some references from I-D to RFC, and from old RFC to 1116 new RFC numbers. 1118 * Added reference to multicast extensions to IPsec architecture 1119 RFC. 1121 * Added a reference to 2464-bis. 1123 * Removed FCC informative references, because not used. 1125 o Updated the affiliation of one author. 1127 o Reformulation of some phrases for better readability, and 1128 correction of typographical errors. 1130 From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave- 1131 ipv6-over-80211ocb-04 1133 o Removed a few informative references pointing to Dx draft IEEE 1134 1609 documents. 1136 o Removed outdated informative references to ETSI documents. 1138 o Added citations to IEEE 1609.2, .3 and .4-2016. 1140 o Minor textual issues. 1142 From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave- 1143 ipv6-over-80211ocb-03 1145 o Keep the previous text on multiple addresses, so remove talk about 1146 MIP6, NEMOv6 and MCoA. 1148 o Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon. 1150 o Clarified the figure showing Infrastructure mode and OCB mode side 1151 by side. 1153 o Added a reference to the IP Security Architecture RFC. 1155 o Detailed the IPv6-per-channel prohibition paragraph which reflects 1156 the discussion at the last IETF IPWAVE WG meeting. 1158 o Added section "Address Mapping -- Unicast". 1160 o Added the ".11 Trailer" to pictures of 802.11 frames. 1162 o Added text about SNAP carrying the Ethertype. 1164 o New RSU definition allowing for it be both a Router and not 1165 necessarily a Router some times. 1167 o Minor textual issues. 1169 From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave- 1170 ipv6-over-80211ocb-02 1172 o Replaced almost all occurences of 802.11p with 802.11-OCB, leaving 1173 only when explanation of evolution was necessary. 1175 o Shortened by removing parameter details from a paragraph in the 1176 Introduction. 1178 o Moved a reference from Normative to Informative. 1180 o Added text in intro clarifying there is no handover spec at IEEE, 1181 and that 1609.2 does provide security services. 1183 o Named the contents the fields of the EthernetII header (including 1184 the Ethertype bitstring). 1186 o Improved relationship between two paragraphs describing the 1187 increase of the Sequence Number in 802.11 header upon IP 1188 fragmentation. 1190 o Added brief clarification of "tracking". 1192 From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave- 1193 ipv6-over-80211ocb-01 1195 o Introduced message exchange diagram illustrating differences 1196 between 802.11 and 802.11 in OCB mode. 1198 o Introduced an appendix listing for information the set of 802.11 1199 messages that may be transmitted in OCB mode. 1201 o Removed appendix sections "Privacy Requirements", "Authentication 1202 Requirements" and "Security Certificate Generation". 1204 o Removed appendix section "Non IP Communications". 1206 o Introductory phrase in the Security Considerations section. 1208 o Improved the definition of "OCB". 1210 o Introduced theoretical stacked layers about IPv6 and IEEE layers 1211 including EPD. 1213 o Removed the appendix describing the details of prohibiting IPv6 on 1214 certain channels relevant to 802.11-OCB. 1216 o Added a brief reference in the privacy text about a precise clause 1217 in IEEE 1609.3 and .4. 1219 o Clarified the definition of a Road Side Unit. 1221 o Removed the discussion about security of WSA (because is non-IP). 1223 o Removed mentioning of the GeoNetworking discussion. 1225 o Moved references to scientific articles to a separate 'overview' 1226 draft, and referred to it. 1228 Appendix B. 802.11p 1230 The term "802.11p" is an earlier definition. The behaviour of 1231 "802.11p" networks is rolled in the document IEEE Std 802.11-2016. 1232 In that document the term 802.11p disappears. Instead, each 802.11p 1233 feature is conditioned by the IEEE Management Information Base (MIB) 1234 attribute "OCBActivated" [IEEE-802.11-2016]. Whenever OCBActivated 1235 is set to true the IEEE Std 802.11-OCB state is activated. For 1236 example, an 802.11 STAtion operating outside the context of a basic 1237 service set has the OCBActivated flag set. Such a station, when it 1238 has the flag set, uses a BSS identifier equal to ff:ff:ff:ff:ff:ff. 1240 Appendix C. Aspects introduced by the OCB mode to 802.11 1242 In the IEEE 802.11-OCB mode, all nodes in the wireless range can 1243 directly communicate with each other without involving authentication 1244 or association procedures. In OCB mode, the manner in which channels 1245 are selected and used is simplified compared to when in BSS mode. 1246 Contrary to BSS mode, at link layer, it is necessary to set 1247 statically the same channel number (or frequency) on two stations 1248 that need to communicate with each other (in BSS mode this channel 1249 set operation is performed automatically during 'scanning'). The 1250 manner in which stations set their channel number in OCB mode is not 1251 specified in this document. Stations STA1 and STA2 can exchange IP 1252 packets only if they are set on the same channel. At IP layer, they 1253 then discover each other by using the IPv6 Neighbor Discovery 1254 protocol. The allocation of a particular channel for a particular 1255 use is defined statically in standards authored by ETSI (in Europe), 1256 FCC in America, and similar organisations in South Korea, Japan and 1257 other parts of the world. 1259 Briefly, the IEEE 802.11-OCB mode has the following properties: 1261 o The use by each node of a 'wildcard' BSSID (i.e., each bit of the 1262 BSSID is set to 1) 1264 o No IEEE 802.11 Beacon frames are transmitted 1266 o No authentication is required in order to be able to communicate 1268 o No association is needed in order to be able to communicate 1270 o No encryption is provided in order to be able to communicate 1272 o Flag dot11OCBActivated is set to true 1274 All the nodes in the radio communication range (IP-OBU and IP-RSU) 1275 receive all the messages transmitted (IP-OBU and IP-RSU) within the 1276 radio communications range. The eventual conflict(s) are resolved by 1277 the MAC CDMA function. 1279 The message exchange diagram in Figure 3 illustrates a comparison 1280 between traditional 802.11 and 802.11 in OCB mode. The 'Data' 1281 messages can be IP packets such as HTTP or others. Other 802.11 1282 management and control frames (non IP) may be transmitted, as 1283 specified in the 802.11 standard. For information, the names of 1284 these messages as currently specified by the 802.11 standard are 1285 listed in Appendix G. 1287 STA AP STA1 STA2 1288 | | | | 1289 |<------ Beacon -------| |<------ Data -------->| 1290 | | | | 1291 |---- Probe Req. ----->| |<------ Data -------->| 1292 |<--- Probe Res. ------| | | 1293 | | |<------ Data -------->| 1294 |---- Auth Req. ------>| | | 1295 |<--- Auth Res. -------| |<------ Data -------->| 1296 | | | | 1297 |---- Asso Req. ------>| |<------ Data -------->| 1298 |<--- Asso Res. -------| | | 1299 | | |<------ Data -------->| 1300 |<------ Data -------->| | | 1301 |<------ Data -------->| |<------ Data -------->| 1303 (i) 802.11 Infrastructure mode (ii) 802.11-OCB mode 1305 Figure 3: Difference between messages exchanged on 802.11 (left) and 1306 802.11-OCB (right) 1308 The interface 802.11-OCB was specified in IEEE Std 802.11p (TM) -2010 1309 [IEEE-802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, 1310 titled "Amendment 6: Wireless Access in Vehicular Environments". 1311 Since then, this amendment has been integrated in IEEE 802.11(TM) 1312 -2012 and -2016 [IEEE-802.11-2016]. 1314 In document 802.11-2016, anything qualified specifically as 1315 "OCBActivated", or "outside the context of a basic service" set to be 1316 true, then it is actually referring to OCB aspects introduced to 1317 802.11. 1319 In order to delineate the aspects introduced by 802.11-OCB to 802.11, 1320 we refer to the earlier [IEEE-802.11p-2010]. The amendment is 1321 concerned with vehicular communications, where the wireless link is 1322 similar to that of Wireless LAN (using a PHY layer specified by 1323 802.11a/b/g/n), but which needs to cope with the high mobility factor 1324 inherent in scenarios of communications between moving vehicles, and 1325 between vehicles and fixed infrastructure deployed along roads. 1326 While 'p' is a letter identifying the Ammendment, just like 'a, b, g' 1327 and 'n' are, 'p' is concerned more with MAC modifications, and a 1328 little with PHY modifications; the others are mainly about PHY 1329 modifications. It is possible in practice to combine a 'p' MAC with 1330 an 'a' PHY by operating outside the context of a BSS with OFDM at 1331 5.4GHz and 5.9GHz. 1333 The 802.11-OCB links are specified to be compatible as much as 1334 possible with the behaviour of 802.11a/b/g/n and future generation 1335 IEEE WLAN links. From the IP perspective, an 802.11-OCB MAC layer 1336 offers practically the same interface to IP as the 802.11a/b/g/n and 1337 802.3. A packet sent by an IP-OBU may be received by one or multiple 1338 IP-RSUs. The link-layer resolution is performed by using the IPv6 1339 Neighbor Discovery protocol. 1341 To support this similarity statement (IPv6 is layered on top of LLC 1342 on top of 802.11-OCB, in the same way that IPv6 is layered on top of 1343 LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on 1344 top of 802.3 (for Ethernet)) it is useful to analyze the differences 1345 between 802.11-OCB and 802.11 specifications. During this analysis, 1346 we note that whereas 802.11-OCB lists relatively complex and numerous 1347 changes to the MAC layer (and very little to the PHY layer), there 1348 are only a few characteristics which may be important for an 1349 implementation transmitting IPv6 packets on 802.11-OCB links. 1351 The most important 802.11-OCB point which influences the IPv6 1352 functioning is the OCB characteristic; an additional, less direct 1353 influence, is the maximum bandwidth afforded by the PHY modulation/ 1354 demodulation methods and channel access specified by 802.11-OCB. The 1355 maximum bandwidth theoretically possible in 802.11-OCB is 54 Mbit/s 1356 (when using, for example, the following parameters: 20 MHz channel; 1357 modulation 64-QAM; coding rate R is 3/4); in practice of IP-over- 1358 802.11-OCB a commonly observed figure is 12Mbit/s; this bandwidth 1359 allows the operation of a wide range of protocols relying on IPv6. 1361 o Operation Outside the Context of a BSS (OCB): the (earlier 1362 802.11p) 802.11-OCB links are operated without a Basic Service Set 1363 (BSS). This means that the frames IEEE 802.11 Beacon, Association 1364 Request/Response, Authentication Request/Response, and similar, 1365 are not used. The used identifier of BSS (BSSID) has a 1366 hexadecimal value always 0xffffffffffff (48 '1' bits, represented 1367 as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' 1368 BSSID), as opposed to an arbitrary BSSID value set by 1369 administrator (e.g. 'My-Home-AccessPoint'). The OCB operation - 1370 namely the lack of beacon-based scanning and lack of 1371 authentication - should be taken into account when the Mobile IPv6 1372 protocol [RFC6275] and the protocols for IP layer security 1373 [RFC4301] are used. The way these protocols adapt to OCB is not 1374 described in this document. 1376 o Timing Advertisement: is a new message defined in 802.11-OCB, 1377 which does not exist in 802.11a/b/g/n. This message is used by 1378 stations to inform other stations about the value of time. It is 1379 similar to the time as delivered by a GNSS system (Galileo, GPS, 1380 ...) or by a cellular system. This message is optional for 1381 implementation. 1383 o Frequency range: this is a characteristic of the PHY layer, with 1384 almost no impact on the interface between MAC and IP. However, it 1385 is worth considering that the frequency range is regulated by a 1386 regional authority (ARCEP, ECC/CEPT based on ENs from ETSI, FCC, 1387 etc.); as part of the regulation process, specific applications 1388 are associated with specific frequency ranges. In the case of 1389 802.11-OCB, the regulator associates a set of frequency ranges, or 1390 slots within a band, to the use of applications of vehicular 1391 communications, in a band known as "5.9GHz". The 5.9GHz band is 1392 different from the 2.4GHz and 5GHz bands used by Wireless LAN. 1393 However, as with Wireless LAN, the operation of 802.11-OCB in 1394 "5.9GHz" bands is exempt from owning a license in EU (in US the 1395 5.9GHz is a licensed band of spectrum; for the fixed 1396 infrastructure an explicit FCC authorization is required; for an 1397 on-board device a 'licensed-by-rule' concept applies: rule 1398 certification conformity is required.) Technical conditions are 1399 different than those of the bands "2.4GHz" or "5GHz". The allowed 1400 power levels, and implicitly the maximum allowed distance between 1401 vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20 1402 dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum 1403 distance of approximately 1km, compared to approximately 50m. 1404 Additionally, specific conditions related to congestion avoidance, 1405 jamming avoidance, and radar detection are imposed on the use of 1406 DSRC (in US) and on the use of frequencies for Intelligent 1407 Transportation Systems (in EU), compared to Wireless LAN 1408 (802.11a/b/g/n). 1410 o 'Half-rate' encoding: as the frequency range, this parameter is 1411 related to PHY, and thus has not much impact on the interface 1412 between the IP layer and the MAC layer. 1414 o In vehicular communications using 802.11-OCB links, there are 1415 strong privacy requirements with respect to addressing. While the 1416 802.11-OCB standard does not specify anything in particular with 1417 respect to MAC addresses, in these settings there exists a strong 1418 need for dynamic change of these addresses (as opposed to the non- 1419 vehicular settings - real wall protection - where fixed MAC 1420 addresses do not currently pose some privacy risks). This is 1421 further described in Section 5. A relevant function is described 1422 in documents IEEE 1609.3-2016 [IEEE-1609.3] and IEEE 1609.4-2016 1423 [IEEE-1609.4]. 1425 Appendix D. Changes Needed on a software driver 802.11a to become a 1426 802.11-OCB driver 1428 The 802.11p amendment modifies both the 802.11 stack's physical and 1429 MAC layers but all the induced modifications can be quite easily 1430 obtained by modifying an existing 802.11a ad-hoc stack. 1432 Conditions for a 802.11a hardware to be 802.11-OCB compliant: 1434 o The PHY entity shall be an orthogonal frequency division 1435 multiplexing (OFDM) system. It must support the frequency bands 1436 on which the regulator recommends the use of ITS communications, 1437 for example using IEEE 802.11-OCB layer, in France: 5875MHz to 1438 5925MHz. 1440 o The OFDM system must provide a "half-clocked" operation using 10 1441 MHz channel spacings. 1443 o The chip transmit spectrum mask must be compliant to the "Transmit 1444 spectrum mask" from the IEEE 802.11p amendment (but experimental 1445 environments tolerate otherwise). 1447 o The chip should be able to transmit up to 44.8 dBm when used by 1448 the US government in the United States, and up to 33 dBm in 1449 Europe; other regional conditions apply. 1451 Changes needed on the network stack in OCB mode: 1453 o Physical layer: 1455 * The chip must use the Orthogonal Frequency Multiple Access 1456 (OFDM) encoding mode. 1458 * The chip must be set in half-mode rate mode (the internal clock 1459 frequency is divided by two). 1461 * The chip must use dedicated channels and should allow the use 1462 of higher emission powers. This may require modifications to 1463 the local computer file that describes regulatory domains 1464 rules, if used by the kernel to enforce local specific 1465 restrictions. Such modifications to the local computer file 1466 must respect the location-specific regulatory rules. 1468 MAC layer: 1470 * All management frames (beacons, join, leave, and others) 1471 emission and reception must be disabled except for frames of 1472 subtype Action and Timing Advertisement (defined below). 1474 * No encryption key or method must be used. 1476 * Packet emission and reception must be performed as in ad-hoc 1477 mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff). 1479 * The functions related to joining a BSS (Association Request/ 1480 Response) and for authentication (Authentication Request/Reply, 1481 Challenge) are not called. 1483 * The beacon interval is always set to 0 (zero). 1485 * Timing Advertisement frames, defined in the amendment, should 1486 be supported. The upper layer should be able to trigger such 1487 frames emission and to retrieve information contained in 1488 received Timing Advertisements. 1490 Appendix E. Protocol Layering 1492 A more theoretical and detailed view of layer stacking, and 1493 interfaces between the IP layer and 802.11-OCB layers, is illustrated 1494 in Figure 4. The IP layer operates on top of the EtherType Protocol 1495 Discrimination (EPD); this Discrimination layer is described in IEEE 1496 Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP 1497 (Link Layer Control Service Access Point). 1499 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1500 | IPv6 | 1501 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ 1502 { LLC_SAP } 802.11-OCB 1503 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary 1504 | EPD | | | 1505 | | MLME | | 1506 +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | 1507 | MAC Sublayer | | | 802.11-OCB 1508 | and ch. coord. | | SME | Services 1509 +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | 1510 | | PLME | | 1511 | PHY Layer | PLME_SAP | 1512 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1514 Figure 4: EtherType Protocol Discrimination 1516 Appendix F. Design Considerations 1518 The networks defined by 802.11-OCB are in many ways similar to other 1519 networks of the 802.11 family. In theory, the encapsulation of IPv6 1520 over 802.11-OCB could be very similar to the operation of IPv6 over 1521 other networks of the 802.11 family. However, the high mobility, 1522 strong link asymmetry and very short connection makes the 802.11-OCB 1523 link significantly different from other 802.11 networks. Also, the 1524 automotive applications have specific requirements for reliability, 1525 security and privacy, which further add to the particularity of the 1526 802.11-OCB link. 1528 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode 1530 For information, at the time of writing, this is the list of IEEE 1531 802.11 messages that may be transmitted in OCB mode, i.e. when 1532 dot11OCBActivated is true in a STA: 1534 o The STA may send management frames of subtype Action and, if the 1535 STA maintains a TSF Timer, subtype Timing Advertisement; 1537 o The STA may send control frames, except those of subtype PS-Poll, 1538 CF-End, and CF-End plus CFAck; 1540 o The STA may send data frames of subtype Data, Null, QoS Data, and 1541 QoS Null. 1543 Appendix H. Examples of Packet Formats 1545 This section describes an example of an IPv6 Packet captured over a 1546 IEEE 802.11-OCB link. 1548 By way of example we show that there is no modification in the 1549 headers when transmitted over 802.11-OCB networks - they are 1550 transmitted like any other 802.11 and Ethernet packets. 1552 We describe an experiment of capturing an IPv6 packet on an 1553 802.11-OCB link. In topology depicted in Figure 5, the packet is an 1554 IPv6 Router Advertisement. This packet is emitted by a Router on its 1555 802.11-OCB interface. The packet is captured on the Host, using a 1556 network protocol analyzer (e.g. Wireshark); the capture is performed 1557 in two different modes: direct mode and 'monitor' mode. The topology 1558 used during the capture is depicted below. 1560 The packet is captured on the Host. The Host is an IP-OBU containing 1561 an 802.11 interface in format PCI express (an ITRI product). The 1562 kernel runs the ath5k software driver with modifications for OCB 1563 mode. The capture tool is Wireshark. The file format for save and 1564 analyze is 'pcap'. The packet is generated by the Router. The 1565 Router is an IP-RSU (ITRI product). 1567 +--------+ +-------+ 1568 | | 802.11-OCB Link | | 1569 ---| Router |--------------------------------| Host | 1570 | | | | 1571 +--------+ +-------+ 1573 Figure 5: Topology for capturing IP packets on 802.11-OCB 1575 During several capture operations running from a few moments to 1576 several hours, no message relevant to the BSSID contexts were 1577 captured (no Association Request/Response, Authentication Req/Resp, 1578 Beacon). This shows that the operation of 802.11-OCB is outside the 1579 context of a BSSID. 1581 Overall, the captured message is identical with a capture of an IPv6 1582 packet emitted on a 802.11b interface. The contents are precisely 1583 similar. 1585 H.1. Capture in Monitor Mode 1587 The IPv6 RA packet captured in monitor mode is illustrated below. 1588 The radio tap header provides more flexibility for reporting the 1589 characteristics of frames. The Radiotap Header is prepended by this 1590 particular stack and operating system on the Host machine to the RA 1591 packet received from the network (the Radiotap Header is not present 1592 on the air). The implementation-dependent Radiotap Header is useful 1593 for piggybacking PHY information from the chip's registers as data in 1594 a packet understandable by userland applications using Socket 1595 interfaces (the PHY interface can be, for example: power levels, data 1596 rate, ratio of signal to noise). 1598 The packet present on the air is formed by IEEE 802.11 Data Header, 1599 Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. 1601 Radiotap Header v0 1602 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1603 |Header Revision| Header Pad | Header length | 1604 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1605 | Present flags | 1606 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1607 | Data Rate | Pad | 1608 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1610 IEEE 802.11 Data Header 1611 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1612 | Type/Subtype and Frame Ctrl | Duration | 1613 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1614 | Receiver Address... 1615 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1616 ... Receiver Address | Transmitter Address... 1617 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1618 ... Transmitter Address | 1619 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1620 | BSS Id... 1621 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1622 ... BSS Id | Frag Number and Seq Number | 1623 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1625 Logical-Link Control Header 1626 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1627 | DSAP |I| SSAP |C| Control field | Org. code... 1628 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1629 ... Organizational Code | Type | 1630 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1632 IPv6 Base Header 1633 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1634 |Version| Traffic Class | Flow Label | 1635 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1636 | Payload Length | Next Header | Hop Limit | 1637 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1638 | | 1639 + + 1640 | | 1641 + Source Address + 1642 | | 1643 + + 1644 | | 1645 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1646 | | 1647 + + 1648 | | 1649 + Destination Address + 1650 | | 1651 + + 1652 | | 1653 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1655 Router Advertisement 1656 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1657 | Type | Code | Checksum | 1658 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1659 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1660 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1661 | Reachable Time | 1662 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1663 | Retrans Timer | 1664 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1665 | Options ... 1666 +-+-+-+-+-+-+-+-+-+-+-+- 1668 The value of the Data Rate field in the Radiotap header is set to 6 1669 Mb/s. This indicates the rate at which this RA was received. 1671 The value of the Transmitter address in the IEEE 802.11 Data Header 1672 is set to a 48bit value. The value of the destination address is 1673 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS 1674 Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network 1675 protocol analyzer as being "broadcast". The Fragment number and 1676 sequence number fields are together set to 0x90C6. 1678 The value of the Organization Code field in the Logical-Link Control 1679 Header is set to 0x0, recognized as "Encapsulated Ethernet". The 1680 value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise 1681 #86DD), recognized as "IPv6". 1683 A Router Advertisement is periodically sent by the router to 1684 multicast group address ff02::1. It is an icmp packet type 134. The 1685 IPv6 Neighbor Discovery's Router Advertisement message contains an 1686 8-bit field reserved for single-bit flags, as described in [RFC4861]. 1688 The IPv6 header contains the link local address of the router 1689 (source) configured via EUI-64 algorithm, and destination address set 1690 to ff02::1. 1692 The Ethernet Type field in the logical-link control header is set to 1693 0x86dd which indicates that the frame transports an IPv6 packet. In 1694 the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 1695 which is the corresponding multicast MAC address. The BSS id is a 1696 broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link 1697 duration between vehicles and the roadside infrastructure, there is 1698 no need in IEEE 802.11-OCB to wait for the completion of association 1699 and authentication procedures before exchanging data. IEEE 1700 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) 1701 and may start communicating as soon as they arrive on the 1702 communication channel. 1704 H.2. Capture in Normal Mode 1706 The same IPv6 Router Advertisement packet described above (monitor 1707 mode) is captured on the Host, in the Normal mode, and depicted 1708 below. 1710 Ethernet II Header 1711 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1712 | Destination... 1713 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1714 ...Destination | Source... 1715 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1716 ...Source | 1717 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1718 | Type | 1719 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1721 IPv6 Base Header 1722 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1723 |Version| Traffic Class | Flow Label | 1724 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1725 | Payload Length | Next Header | Hop Limit | 1726 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1727 | | 1728 + + 1729 | | 1730 + Source Address + 1731 | | 1732 + + 1733 | | 1734 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1735 | | 1736 + + 1737 | | 1738 + Destination Address + 1739 | | 1740 + + 1741 | | 1742 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1744 Router Advertisement 1745 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1746 | Type | Code | Checksum | 1747 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1748 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1749 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1750 | Reachable Time | 1751 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1752 | Retrans Timer | 1753 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1754 | Options ... 1755 +-+-+-+-+-+-+-+-+-+-+-+- 1757 One notices that the Radiotap Header, the IEEE 802.11 Data Header and 1758 the Logical-Link Control Headers are not present. On the other hand, 1759 a new header named Ethernet II Header is present. 1761 The Destination and Source addresses in the Ethernet II header 1762 contain the same values as the fields Receiver Address and 1763 Transmitter Address present in the IEEE 802.11 Data Header in the 1764 "monitor" mode capture. 1766 The value of the Type field in the Ethernet II header is 0x86DD 1767 (recognized as "IPv6"); this value is the same value as the value of 1768 the field Type in the Logical-Link Control Header in the "monitor" 1769 mode capture. 1771 The knowledgeable experimenter will no doubt notice the similarity of 1772 this Ethernet II Header with a capture in normal mode on a pure 1773 Ethernet cable interface. 1775 An Adaptation layer is inserted on top of a pure IEEE 802.11 MAC 1776 layer, in order to adapt packets, before delivering the payload data 1777 to the applications. It adapts 802.11 LLC/MAC headers to Ethernet II 1778 headers. In further detail, this adaptation consists in the 1779 elimination of the Radiotap, 802.11 and LLC headers, and in the 1780 insertion of the Ethernet II header. In this way, IPv6 runs straight 1781 over LLC over the 802.11-OCB MAC layer; this is further confirmed by 1782 the use of the unique Type 0x86DD. 1784 Appendix I. Extra Terminology 1786 The following terms are defined outside the IETF. They are used to 1787 define the main terms in the main terminology section Section 2. 1789 DSRC (Dedicated Short Range Communication): a term defined outside 1790 the IETF. The US Federal Communications Commission (FCC) Dedicated 1791 Short Range Communication (DSRC) is defined in the Code of Federal 1792 Regulations (CFR) 47, Parts 90 and 95. This Code is referred in the 1793 definitions below. At the time of the writing of this Internet 1794 Draft, the last update of this Code was dated October 1st, 2010. 1796 DSRCS (Dedicated Short-Range Communications Services): a term defined 1797 outside the IETF. The use of radio techniques to transfer data over 1798 short distances between roadside and mobile units, between mobile 1799 units, and between portable and mobile units to perform operations 1800 related to the improvement of traffic flow, traffic safety, and other 1801 intelligent transportation service applications in a variety of 1802 environments. DSRCS systems may also transmit status and 1803 instructional messages related to the units involve. [Ref. 47 CFR 1804 90.7 - Definitions] 1805 OBU (On-Board Unit): a term defined outside the IETF. An On-Board 1806 Unit is a DSRCS transceiver that is normally mounted in or on a 1807 vehicle, or which in some instances may be a portable unit. An OBU 1808 can be operational while a vehicle or person is either mobile or 1809 stationary. The OBUs receive and contend for time to transmit on one 1810 or more radio frequency (RF) channels. Except where specifically 1811 excluded, OBU operation is permitted wherever vehicle operation or 1812 human passage is permitted. The OBUs mounted in vehicles are 1813 licensed by rule under part 95 of the respective chapter and 1814 communicate with Roadside Units (RSUs) and other OBUs. Portable OBUs 1815 are also licensed by rule under part 95 of the respective chapter. 1816 OBU operations in the Unlicensed National Information Infrastructure 1817 (UNII) Bands follow the rules in those bands. - [CFR 90.7 - 1818 Definitions]. 1820 RSU (Road-Side Unit): a term defined outside of IETF. A Roadside 1821 Unit is a DSRC transceiver that is mounted along a road or pedestrian 1822 passageway. An RSU may also be mounted on a vehicle or is hand 1823 carried, but it may only operate when the vehicle or hand- carried 1824 unit is stationary. Furthermore, an RSU operating under the 1825 respectgive part is restricted to the location where it is licensed 1826 to operate. However, portable or hand-held RSUs are permitted to 1827 operate where they do not interfere with a site-licensed operation. 1828 A RSU broadcasts data to OBUs or exchanges data with OBUs in its 1829 communications zone. An RSU also provides channel assignments and 1830 operating instructions to OBUs in its communications zone, when 1831 required. - [CFR 90.7 - Definitions]. 1833 Authors' Addresses 1835 Alexandre Petrescu 1836 CEA, LIST 1837 CEA Saclay 1838 Gif-sur-Yvette , Ile-de-France 91190 1839 France 1841 Phone: +33169089223 1842 Email: Alexandre.Petrescu@cea.fr 1844 Nabil Benamar 1845 Moulay Ismail University 1846 Morocco 1848 Phone: +212670832236 1849 Email: n.benamar@est.umi.ac.ma 1850 Jerome Haerri 1851 Eurecom 1852 Sophia-Antipolis 06904 1853 France 1855 Phone: +33493008134 1856 Email: Jerome.Haerri@eurecom.fr 1858 Jong-Hyouk Lee 1859 Sangmyung University 1860 31, Sangmyeongdae-gil, Dongnam-gu 1861 Cheonan 31066 1862 Republic of Korea 1864 Email: jonghyouk@smu.ac.kr 1866 Thierry Ernst 1867 YoGoKo 1868 France 1870 Email: thierry.ernst@yogoko.fr