idnits 2.17.1 draft-ietf-ipwave-ipv6-over-80211ocb-35.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 (April 8, 2019) is 1844 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reference: RFC 7042 (Obsoleted by RFC 9542) ** Downref: Normative reference to an Informational RFC: RFC 7721 == Outdated reference: A later version (-15) exists of draft-ietf-mboned-ieee802-mcast-problems-04 Summary: 5 errors (**), 0 flaws (~~), 3 warnings (==), 2 comments (--).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: October 10, 2019 Moulay Ismail University 6 J. Haerri 7 Eurecom 8 J. Lee 9 Sangmyung University 10 T. Ernst 11 YoGoKo 12 April 8, 2019 14 Transmission of IPv6 Packets over IEEE 802.11 Networks operating in mode 15 Outside the Context of a Basic Service Set (IPv6-over-80211-OCB) 16 draft-ietf-ipwave-ipv6-over-80211ocb-35 18 Abstract 20 In order to transmit IPv6 packets on IEEE 802.11 networks running 21 outside the context of a basic service set (OCB, earlier "802.11p") 22 there is a need to define a few parameters such as the supported 23 Maximum Transmission Unit size on the 802.11-OCB link, the header 24 format preceding the IPv6 header, the Type value within it, and 25 others. This document describes these parameters for IPv6 and IEEE 26 802.11-OCB networks; it portrays the layering of IPv6 on 802.11-OCB 27 similarly to other known 802.11 and Ethernet layers - by using an 28 Ethernet Adaptation Layer. 30 Status of This Memo 32 This Internet-Draft is submitted in full conformance with the 33 provisions of BCP 78 and BCP 79. 35 Internet-Drafts are working documents of the Internet Engineering 36 Task Force (IETF). Note that other groups may also distribute 37 working documents as Internet-Drafts. The list of current Internet- 38 Drafts is at https://datatracker.ietf.org/drafts/current/. 40 Internet-Drafts are draft documents valid for a maximum of six months 41 and may be updated, replaced, or obsoleted by other documents at any 42 time. It is inappropriate to use Internet-Drafts as reference 43 material or to cite them other than as "work in progress." 45 This Internet-Draft will expire on October 10, 2019. 47 Copyright Notice 49 Copyright (c) 2019 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (https://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with respect 57 to this document. Code Components extracted from this document must 58 include Simplified BSD License text as described in Section 4.e of 59 the Trust Legal Provisions and are provided without warranty as 60 described in the Simplified BSD License. 62 Table of Contents 64 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 65 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 66 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 4 67 4. IPv6 over 802.11-OCB . . . . . . . . . . . . . . . . . . . . 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. Stateless Autoconfiguration . . . . . . . . . . . . . . . 7 73 4.5. Address Mapping . . . . . . . . . . . . . . . . . . . . . 8 74 4.5.1. Address Mapping -- Unicast . . . . . . . . . . . . . 8 75 4.5.2. Address Mapping -- Multicast . . . . . . . . . . . . 8 76 4.6. Subnet Structure . . . . . . . . . . . . . . . . . . . . 8 77 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9 78 5.1. Privacy Considerations . . . . . . . . . . . . . . . . . 10 79 5.1.1. Privacy Risks of Meaningful info in Interface IDs . . 10 80 5.2. MAC Address and Interface ID Generation . . . . . . . . . 11 81 5.3. Pseudonym Handling . . . . . . . . . . . . . . . . . . . 11 82 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 83 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 12 84 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 85 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 86 9.1. Normative References . . . . . . . . . . . . . . . . . . 13 87 9.2. Informative References . . . . . . . . . . . . . . . . . 15 88 Appendix A. ChangeLog . . . . . . . . . . . . . . . . . . . . . 17 89 Appendix B. 802.11p . . . . . . . . . . . . . . . . . . . . . . 27 90 Appendix C. Aspects introduced by the OCB mode to 802.11 . . . . 27 91 Appendix D. Changes Needed on a software driver 802.11a to 92 become a 802.11-OCB driver . . . 32 93 Appendix E. Protocol Layering . . . . . . . . . . . . . . . . . 33 94 Appendix F. Design Considerations . . . . . . . . . . . . . . . 34 95 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode . . . . 34 96 Appendix H. Examples of Packet Formats . . . . . . . . . . . . . 34 97 H.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . 35 98 H.2. Capture in Normal Mode . . . . . . . . . . . . . . . . . 38 99 Appendix I. Extra Terminology . . . . . . . . . . . . . . . . . 40 100 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 41 102 1. Introduction 104 This document describes the transmission of IPv6 packets on IEEE Std 105 802.11-OCB networks [IEEE-802.11-2016] (a.k.a "802.11p" see 106 Appendix B, Appendix C and Appendix D). This involves the layering 107 of IPv6 networking on top of the IEEE 802.11 MAC layer, with an LLC 108 layer. Compared to running IPv6 over the Ethernet MAC layer, there 109 is no modification expected to IEEE Std 802.11 MAC and Logical Link 110 sublayers: IPv6 works fine directly over 802.11-OCB too, with an LLC 111 layer. 113 The IPv6 network layer operates on 802.11-OCB in the same manner as 114 operating on Ethernet, but there are two kinds of exceptions: 116 o Exceptions due to different operation of IPv6 network layer on 117 802.11 than on Ethernet. To satisfy these exceptions, this 118 document describes an Ethernet Adaptation Layer between Ethernet 119 headers and 802.11 headers. The Ethernet Adaptation Layer is 120 described Section 4.2.1. The operation of IP on Ethernet is 121 described in [RFC1042], [RFC2464] and 122 [I-D.hinden-6man-rfc2464bis]. 124 o Exceptions due to the OCB nature of 802.11-OCB compared to 802.11. 125 This has impacts on security, privacy, subnet structure and 126 movement detection. For security and privacy recommendations see 127 Section 5 and Section 4.4. The subnet structure is described in 128 Section 4.6. The movement detection on OCB links is not described 129 in this document. 131 In the published literature, many documents describe aspects and 132 problems related to running IPv6 over 802.11-OCB: 133 [I-D.ietf-ipwave-vehicular-networking-survey]. 135 2. Terminology 137 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 138 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 139 "OPTIONAL" in this document are to be interpreted as described in BCP 140 14 [RFC2119] [RFC8174] when, and only when, they appear in all 141 capitals, as shown here. 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 4. IPv6 over 802.11-OCB 186 4.1. Maximum Transmission Unit (MTU) 188 The default MTU for IP packets on 802.11-OCB MUST be 1500 octets. It 189 is the same value as IPv6 packets on Ethernet links, as specified in 190 [RFC2464]. This value of the MTU respects the recommendation that 191 every link on the Internet must have a minimum MTU of 1280 octets 192 (stated in [RFC8200], and the recommendations therein, especially 193 with respect to fragmentation). 195 4.2. Frame Format 197 IP packets MUST be transmitted over 802.11-OCB media as QoS Data 198 frames whose format is specified in IEEE 802.11(TM) -2016 199 [IEEE-802.11-2016]. 201 The IPv6 packet transmitted on 802.11-OCB MUST be immediately 202 preceded by a Logical Link Control (LLC) header and an 802.11 header. 203 In the LLC header, and in accordance with the EtherType Protocol 204 Discrimination (EPD, see Appendix E), the value of the Type field 205 MUST be set to 0x86DD (IPv6). In the 802.11 header, the value of the 206 Subtype sub-field in the Frame Control field MUST be set to 8 (i.e. 207 'QoS Data'); the value of the Traffic Identifier (TID) sub-field of 208 the QoS Control field of the 802.11 header MUST be set to binary 001 209 (i.e. User Priority 'Background', QoS Access Category 'AC_BK'). 211 To simplify the Application Programming Interface (API) between the 212 operating system and the 802.11-OCB media, device drivers MAY 213 implement an Ethernet Adaptation Layer that translates Ethernet II 214 frames to the 802.11 format and vice versa. An Ethernet Adaptation 215 Layer is described in Section 4.2.1. 217 4.2.1. Ethernet Adaptation Layer 219 An 'adaptation' layer is inserted between a MAC layer and the 220 Networking layer. This is used to transform some parameters between 221 their form expected by the IP stack and the form provided by the MAC 222 layer. 224 An Ethernet Adaptation Layer makes an 802.11 MAC look to IP 225 Networking layer as a more traditional Ethernet layer. At reception, 226 this layer takes as input the IEEE 802.11 header and the Logical-Link 227 Layer Control Header and produces an Ethernet II Header. At sending, 228 the reverse operation is performed. 230 The operation of the Ethernet Adaptation Layer is depicted by the 231 double arrow in Figure 1. 233 +------------------+------------+-------------+---------+-----------+ 234 | 802.11 header | LLC Header | IPv6 Header | Payload |.11 Trailer| 235 +------------------+------------+-------------+---------+-----------+ 236 \ / \ / 237 --------------------------- -------- 238 \---------------------------------------------/ 239 ^ 240 | 241 802.11-to-Ethernet Adaptation Layer 242 | 243 v 244 +---------------------+-------------+---------+ 245 | Ethernet II Header | IPv6 Header | Payload | 246 +---------------------+-------------+---------+ 248 Figure 1: Operation of the Ethernet Adaptation Layer 250 The Receiver and Transmitter Address fields in the 802.11 header MUST 251 contain the same values as the Destination and the Source Address 252 fields in the Ethernet II Header, respectively. The value of the 253 Type field in the LLC Header MUST be the same as the value of the 254 Type field in the Ethernet II Header. That value MUST be set to 255 0x86DD (IPv6). 257 The ".11 Trailer" contains solely a 4-byte Frame Check Sequence. 259 The placement of IPv6 networking layer on Ethernet Adaptation Layer 260 is illustrated in Figure 2. 262 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 263 | IPv6 | 264 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 265 | Ethernet Adaptation Layer | 266 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 267 | 802.11 MAC | 268 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 269 | 802.11 PHY | 270 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 272 Figure 2: Ethernet Adaptation Layer stacked with other layers 274 (in the above figure, a 802.11 profile is represented; this is used 275 also for 802.11-OCB profile.) 277 4.3. Link-Local Addresses 279 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 280 MAY be assigned to an 802.11-OCB interface. Among these types of 281 addresses only the IPv6 link-local addresses MAY be formed using an 282 EUI-64 identifier, in particular during transition time. 284 If the IPv6 link-local address is formed using an EUI-64 identifier, 285 then the mechanism of forming that address is the same mechanism as 286 used to form an IPv6 link-local address on Ethernet links. This 287 mechanism is described in section 5 of [RFC2464]. 289 For privacy, the link-local address MAY be formed according to the 290 mechanisms described in Section 5.2. 292 4.4. Stateless Autoconfiguration 294 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 295 MAY be assigned to an 802.11-OCB interface. This section describes 296 the formation of Interface Identifiers for IPv6 addresses of type 297 'Global' or 'Unique Local'. For Interface Identifiers for IPv6 298 address of type 'Link-Local' see Section 4.3. 300 The Interface Identifier for an 802.11-OCB interface is formed using 301 the same rules as the Interface Identifier for an Ethernet interface; 302 the RECOMMENDED method for forming stable Interface Identifiers 303 (IIDs) is described in [RFC8064]. The method of forming IIDs 304 described in section 4 of [RFC2464] MAY be used during transition 305 time, in particular for IPv6 link-local addresses. 307 The bits in the Interface Identifier have no generic meaning and the 308 identifier should be treated as an opaque value. The bits 309 'Universal' and 'Group' in the identifier of an 802.11-OCB interface 310 are significant, as this is an IEEE link-layer address. The details 311 of this significance are described in [RFC7136]. 313 Semantically opaque Interface Identifiers, instead of meaningful 314 Interface Identifiers derived from a valid and meaningful MAC address 315 ([RFC2464], section 4), help avoid certain privacy risks (see the 316 risks mentioned in Section 5.1.1). If semantically opaque Interface 317 Identifiers are needed, they MAY be generated using the method for 318 generating semantically opaque Interface Identifiers with IPv6 319 Stateless Address Autoconfiguration given in [RFC7217]. Typically, 320 an opaque Interface Identifier is formed starting from identifiers 321 different than the MAC addresses, and from cryptographically strong 322 material. Thus, privacy sensitive information is absent from 323 Interface IDs, because it is impossible to calculate back the initial 324 value from which the Interface ID was first generated (intuitively, 325 it is as hard as mentally finding the square root of a number, and as 326 impossible as trying to use computers to identify quickly whether a 327 large number is prime). 329 Some applications that use IPv6 packets on 802.11-OCB links (among 330 other link types) may benefit from IPv6 addresses whose Interface 331 Identifiers don't change too often. It is RECOMMENDED to use the 332 mechanisms described in RFC 7217 to permit the use of Stable 333 Interface Identifiers that do not change within one subnet prefix. A 334 possible source for the Net-Iface Parameter is a virtual interface 335 name, or logical interface name, that is decided by a local 336 administrator. 338 4.5. Address Mapping 340 Unicast and multicast address mapping MUST follow the procedures 341 specified for Ethernet interfaces in sections 6 and 7 of [RFC2464]. 343 4.5.1. Address Mapping -- Unicast 345 The procedure for mapping IPv6 unicast addresses into Ethernet link- 346 layer addresses is described in [RFC4861]. 348 4.5.2. Address Mapping -- Multicast 350 The multicast address mapping is performed according to the method 351 specified in section 7 of [RFC2464]. The meaning of the value "3333" 352 mentioned in that section 7 of [RFC2464] is defined in section 2.3.1 353 of [RFC7042]. 355 Transmitting IPv6 packets to multicast destinations over 802.11 links 356 proved to have some performance issues 357 [I-D.ietf-mboned-ieee802-mcast-problems]. These issues may be 358 exacerbated in OCB mode. Solutions for these problems SHOULD 359 consider the OCB mode of operation. 361 4.6. Subnet Structure 363 A subnet is formed by the external 802.11-OCB interfaces of vehicles 364 that are in close range (not by their in-vehicle interfaces). This 365 subnet MUST use at least the link-local prefix fe80::/10 and the 366 interfaces MUST be assigned IPv6 addresses of type link-local. 368 The structure of this subnet is ephemeral, in that it is strongly 369 influenced by the mobility of vehicles: the hidden terminal effects 370 appear; the 802.11 networks in OCB mode may be considered as 'ad-hoc' 371 networks with an addressing model as described in [RFC5889]. On 372 another hand, the structure of the internal subnets in each car is 373 relatively stable. 375 As recommended in [RFC5889], when the timing requirements are very 376 strict (e.g. fast drive through IP-RSU coverage), no on-link subnet 377 prefix should be configured on an 802.11-OCB interface. In such 378 cases, the exclusive use of IPv6 link-local addresses is RECOMMENDED. 380 Additionally, even if the timing requirements are not very strict 381 (e.g. the moving subnet formed by two following vehicles is stable, a 382 fixed IP-RSU is absent), the subnet is disconnected from the Internet 383 (a default route is absent), and the addressing peers are equally 384 qualified (impossible to determine that some vehicle owns and 385 distributes addresses to others) the use of link-local addresses is 386 RECOMMENDED. 388 The Neighbor Discovery protocol (ND) [RFC4861] MUST be used over 389 802.11-OCB links. 391 Protocols like Mobile IPv6 [RFC6275] and DNAv6 [RFC6059], which 392 depend on timely movement detection, might need additional tuning 393 work to handle the lack of link-layer notifications during handover. 394 This is for further study. 396 5. Security Considerations 398 Any security mechanism at the IP layer or above that may be carried 399 out for the general case of IPv6 may also be carried out for IPv6 400 operating over 802.11-OCB. 402 The OCB operation is stripped off of all existing 802.11 link-layer 403 security mechanisms. There is no encryption applied below the 404 network layer running on 802.11-OCB. At application layer, the IEEE 405 1609.2 document [IEEE-1609.2] does provide security services for 406 certain applications to use; application-layer mechanisms are out-of- 407 scope of this document. On another hand, a security mechanism 408 provided at networking layer, such as IPsec [RFC4301], may provide 409 data security protection to a wider range of applications. 411 802.11-OCB does not provide any cryptographic protection, because it 412 operates outside the context of a BSS (no Association Request/ 413 Response, no Challenge messages). Any attacker can therefore just 414 sit in the near range of vehicles, sniff the network (just set the 415 interface card's frequency to the proper range) and perform attacks 416 without needing to physically break any wall. Such a link is less 417 protected than commonly used links (wired link or protected 802.11). 419 The potential attack vectors are: MAC address spoofing, IP address 420 and session hijacking, and privacy violation Section 5.1. 422 Within the IPsec Security Architecture [RFC4301], the IPsec AH and 423 ESP headers [RFC4302] and [RFC4303] respectively, its multicast 424 extensions [RFC5374], HTTPS [RFC2818] and SeND [RFC3971] protocols 425 can be used to protect communications. Further, the assistance of 426 proper Public Key Infrastructure (PKI) protocols [RFC4210] is 427 necessary to establish credentials. More IETF protocols are 428 available in the toolbox of the IP security protocol designer. 429 Certain ETSI protocols related to security protocols in Intelligent 430 Transportation Systems are described in [ETSI-sec-archi]. 432 5.1. Privacy Considerations 434 As with all Ethernet and 802.11 interface identifiers ([RFC7721]), 435 the identifier of an 802.11-OCB interface may involve privacy, MAC 436 address spoofing and IP address hijacking risks. A vehicle embarking 437 an IP-OBU whose egress interface is 802.11-OCB may expose itself to 438 eavesdropping and subsequent correlation of data; this may reveal 439 data considered private by the vehicle owner; there is a risk of 440 being tracked. In outdoors public environments, where vehicles 441 typically circulate, the privacy risks are more important than in 442 indoors settings. It is highly likely that attacker sniffers are 443 deployed along routes which listen for IEEE frames, including IP 444 packets, of vehicles passing by. For this reason, in the 802.11-OCB 445 deployments, there is a strong necessity to use protection tools such 446 as dynamically changing MAC addresses Section 5.2, semantically 447 opaque Interface Identifiers and stable Interface Identifiers 448 Section 4.4. This may help mitigate privacy risks to a certain 449 level. 451 5.1.1. Privacy Risks of Meaningful info in Interface IDs 453 The privacy risks of using MAC addresses displayed in Interface 454 Identifiers are important. The IPv6 packets can be captured easily 455 in the Internet and on-link in public roads. For this reason, an 456 attacker may realize many attacks on privacy. One such attack on 457 802.11-OCB is to capture, store and correlate Company ID information 458 present in MAC addresses of many cars (e.g. listen for Router 459 Advertisements, or other IPv6 application data packets, and record 460 the value of the source address in these packets). Further 461 correlation of this information with other data captured by other 462 means, or other visual information (car color, others) MAY constitute 463 privacy risks. 465 5.2. MAC Address and Interface ID Generation 467 In 802.11-OCB networks, the MAC addresses MAY change during well 468 defined renumbering events. In the moment the MAC address is changed 469 on an 802.11-OCB interface all the Interface Identifiers of IPv6 470 addresses assigned to that interface MUST change. 472 The policy dictating when the MAC address is changed on the 473 802.11-OCB interface is to-be-determined. For more information on 474 the motivation of this policy please refer to the privacy discussion 475 in Appendix C. 477 A 'randomized' MAC address has the following characteristics: 479 o Bit "Local/Global" set to "locally admninistered". 481 o Bit "Unicast/Multicast" set to "Unicast". 483 o The 46 remaining bits are set to a random value, using a random 484 number generator that meets the requirements of [RFC4086]. 486 To meet the randomization requirements for the 46 remaining bits, a 487 hash function may be used. For example, the SHA256 hash function may 488 be used with input a 256 bit local secret, the 'nominal' MAC Address 489 of the interface, and a representation of the date and time of the 490 renumbering event. 492 A randomized Interface ID has the same characteristics of a 493 randomized MAC address, except the length in bits. A MAC address 494 SHOULD be of length 48 decimal. An Interface ID SHOULD be of length 495 64 decimal for all types of IPv6 addresses. In the particular case 496 of IPv6 link-local addresses, the length of the Interface ID MAY be 497 118 decimal. 499 5.3. Pseudonym Handling 501 The demand for privacy protection of vehicles' and drivers' 502 identities, which could be granted by using a pseudonym or alias 503 identity at the same time, may hamper the required confidentiality of 504 messages and trust between participants - especially in safety 505 critical vehicular communication. 507 o Particular challenges arise when the pseudonymization mechanism 508 used relies on (randomized) re-addressing. 510 o A proper pseudonymization tool operated by a trusted third party 511 may be needed to ensure both aspects simultaneously (privacy 512 protection on one hand and trust between participants on another 513 hand). 515 o This is discussed in Section 4.4 and Section 5 of this document. 517 o Pseudonymity is also discussed in 518 [I-D.ietf-ipwave-vehicular-networking-survey] in its sections 519 4.2.4 and 5.1.2. 521 6. IANA Considerations 523 No request to IANA. 525 7. Contributors 527 Christian Huitema, Tony Li. 529 Romain Kuntz contributed extensively about IPv6 handovers between 530 links running outside the context of a BSS (802.11-OCB links). 532 Tim Leinmueller contributed the idea of the use of IPv6 over 533 802.11-OCB for distribution of certificates. 535 Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey 536 Voronov provided significant feedback on the experience of using IP 537 messages over 802.11-OCB in initial trials. 539 Michelle Wetterwald contributed extensively the MTU discussion, 540 offered the ETSI ITS perspective, and reviewed other parts of the 541 document. 543 8. Acknowledgements 545 The authors would like to thank Witold Klaudel, Ryuji Wakikawa, 546 Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan 547 Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray 548 Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, 549 Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne, 550 Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark, 551 Bob Moskowitz, Andrew Dryden, Georg Mayer, Dorothy Stanley, Sandra 552 Cespedes, Mariano Falcitelli, Sri Gundavelli, Abdussalam Baryun, 553 Margaret Cullen, Erik Kline, Carlos Jesus Bernardos Cano, Ronald in 554 't Velt, Katrin Sjoberg, Roland Bless, Tijink Jasja, Kevin Smith, 555 Brian Carpenter, Julian Reschke, Mikael Abrahamsson, Dirk von Hugo, 556 Lorenzo Colitti, Pascal Thubert and William Whyte. Their valuable 557 comments clarified particular issues and generally helped to improve 558 the document. 560 Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB 561 drivers for linux and described how. 563 For the multicast discussion, the authors would like to thank Owen 564 DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and 565 participants to discussions in network working groups. 567 The authors would like to thank participants to the Birds-of- 568 a-Feather "Intelligent Transportation Systems" meetings held at IETF 569 in 2016. 571 Human Rights Protocol Considerations review by Amelia Andersdotter. 573 9. References 575 9.1. Normative References 577 [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission 578 of IP datagrams over IEEE 802 networks", STD 43, RFC 1042, 579 DOI 10.17487/RFC1042, February 1988, 580 . 582 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 583 Requirement Levels", BCP 14, RFC 2119, 584 DOI 10.17487/RFC2119, March 1997, 585 . 587 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 588 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 589 . 591 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 592 DOI 10.17487/RFC2818, May 2000, 593 . 595 [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related 596 Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, 597 . 599 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 600 "SEcure Neighbor Discovery (SEND)", RFC 3971, 601 DOI 10.17487/RFC3971, March 2005, 602 . 604 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 605 "Randomness Requirements for Security", BCP 106, RFC 4086, 606 DOI 10.17487/RFC4086, June 2005, 607 . 609 [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast 610 Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005, 611 . 613 [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, 614 "Internet X.509 Public Key Infrastructure Certificate 615 Management Protocol (CMP)", RFC 4210, 616 DOI 10.17487/RFC4210, September 2005, 617 . 619 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 620 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 621 2006, . 623 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 624 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 625 December 2005, . 627 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 628 DOI 10.17487/RFC4302, December 2005, 629 . 631 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 632 RFC 4303, DOI 10.17487/RFC4303, December 2005, 633 . 635 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 636 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 637 DOI 10.17487/RFC4861, September 2007, 638 . 640 [RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast 641 Extensions to the Security Architecture for the Internet 642 Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008, 643 . 645 [RFC5415] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, 646 Ed., "Control And Provisioning of Wireless Access Points 647 (CAPWAP) Protocol Specification", RFC 5415, 648 DOI 10.17487/RFC5415, March 2009, 649 . 651 [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing 652 Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889, 653 September 2010, . 655 [RFC6059] Krishnan, S. and G. Daley, "Simple Procedures for 656 Detecting Network Attachment in IPv6", RFC 6059, 657 DOI 10.17487/RFC6059, November 2010, 658 . 660 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 661 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 662 2011, . 664 [RFC7042] Eastlake 3rd, D. and J. Abley, "IANA Considerations and 665 IETF Protocol and Documentation Usage for IEEE 802 666 Parameters", BCP 141, RFC 7042, DOI 10.17487/RFC7042, 667 October 2013, . 669 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 670 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 671 February 2014, . 673 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 674 Interface Identifiers with IPv6 Stateless Address 675 Autoconfiguration (SLAAC)", RFC 7217, 676 DOI 10.17487/RFC7217, April 2014, 677 . 679 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 680 Considerations for IPv6 Address Generation Mechanisms", 681 RFC 7721, DOI 10.17487/RFC7721, March 2016, 682 . 684 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 685 "Recommendation on Stable IPv6 Interface Identifiers", 686 RFC 8064, DOI 10.17487/RFC8064, February 2017, 687 . 689 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 690 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 691 May 2017, . 693 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 694 (IPv6) Specification", STD 86, RFC 8200, 695 DOI 10.17487/RFC8200, July 2017, 696 . 698 9.2. Informative References 700 [ETSI-sec-archi] 701 "ETSI TS 102 940 V1.2.1 (2016-11), ETSI Technical 702 Specification, Intelligent Transport Systems (ITS); 703 Security; ITS communications security architecture and 704 security management, November 2016. Downloaded on 705 September 9th, 2017, freely available from ETSI website at 706 URL http://www.etsi.org/deliver/ 707 etsi_ts/102900_102999/102940/01.02.01_60/ 708 ts_102940v010201p.pdf". 710 [I-D.hinden-6man-rfc2464bis] 711 Crawford, M. and R. Hinden, "Transmission of IPv6 Packets 712 over Ethernet Networks", draft-hinden-6man-rfc2464bis-02 713 (work in progress), March 2017. 715 [I-D.ietf-ipwave-vehicular-networking-survey] 716 Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M. 717 Wetterwald, "Survey on IP-based Vehicular Networking for 718 Intelligent Transportation Systems", draft-ietf-ipwave- 719 vehicular-networking-survey-00 (work in progress), July 720 2017. 722 [I-D.ietf-mboned-ieee802-mcast-problems] 723 Perkins, C., McBride, M., Stanley, D., Kumari, W., and J. 724 Zuniga, "Multicast Considerations over IEEE 802 Wireless 725 Media", draft-ietf-mboned-ieee802-mcast-problems-04 (work 726 in progress), November 2018. 728 [IEEE-1609.2] 729 "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access 730 in Vehicular Environments (WAVE) -- Security Services for 731 Applications and Management Messages. Example URL 732 http://ieeexplore.ieee.org/document/7426684/ accessed on 733 August 17th, 2017.". 735 [IEEE-1609.3] 736 "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access 737 in Vehicular Environments (WAVE) -- Networking Services. 738 Example URL http://ieeexplore.ieee.org/document/7458115/ 739 accessed on August 17th, 2017.". 741 [IEEE-1609.4] 742 "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access 743 in Vehicular Environments (WAVE) -- Multi-Channel 744 Operation. Example URL 745 http://ieeexplore.ieee.org/document/7435228/ accessed on 746 August 17th, 2017.". 748 [IEEE-802.11-2016] 749 "IEEE Standard 802.11-2016 - IEEE Standard for Information 750 Technology - Telecommunications and information exchange 751 between systems Local and metropolitan area networks - 752 Specific requirements - Part 11: Wireless LAN Medium 753 Access Control (MAC) and Physical Layer (PHY) 754 Specifications. Status - Active Standard. Description 755 retrieved freely on September 12th, 2017, at URL 756 https://standards.ieee.org/findstds/ 757 standard/802.11-2016.html". 759 [IEEE-802.11p-2010] 760 "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information 761 Technology - Telecommunications and information exchange 762 between systems - Local and metropolitan area networks - 763 Specific requirements, Part 11: Wireless LAN Medium Access 764 Control (MAC) and Physical Layer (PHY) Specifications, 765 Amendment 6: Wireless Access in Vehicular Environments; 766 document freely available at URL 767 http://standards.ieee.org/getieee802/ 768 download/802.11p-2010.pdf retrieved on September 20th, 769 2013.". 771 Appendix A. ChangeLog 773 The changes are listed in reverse chronological order, most recent 774 changes appearing at the top of the list. 776 -35: addressing the the intarea review: clarified a small apparent 777 contradiction between two parts of text that use the old MAC-based 778 IIDs (clarified by using qualifiers from each other: transition time, 779 and ll addresses); sequenced closer the LL and Stateless Autoconf 780 sections, instead of spacing them; shortened the paragraph of Opaque 781 IIDs; moved the privacy risks of in-clear IIDs in the security 782 section; removed a short phrase duplicating the idea of privacy 783 risks; added third time a reference to the 802.11-2016 document; used 784 'the hidden terminal' text; updated the Terminology section with new 785 BCP-14 text 'MUST' to include RFC8174. 787 -33: substituted 'movement detection' for 'handover behaviour' in 788 introductory text; removed redundant phrase referring to Security 789 Considerations section; removed the phrase about forming mechanisms 790 being left out, as IP is not much concerned about L2 forming; moved 791 the Pseudonym section from main section to end of Security 792 Considerations section (and clarified 'concurrently'); capitalized 793 SHOULD consider OCB in WiFi multicast problems, and referred to more 794 recent I-D on topic; removed several phrases in a paragraph about 795 oui.txt and MAC presence in IPv6 address, as they are well known 796 info, but clarified the example of privacy risk of Company ID in MAC 797 addresses in public roads; clarified that ND MUST be used over 798 802.11-OCB. 800 -32: significantly shortened the relevant ND/OCB paragraph. It now 801 just states ND is used over OCB, w/o detailing. 803 -31: filled in the section titled "Pseudonym Handling"; removed a 804 'MAY NOT' phrase about possibility of having other prefix than the LL 805 on the link between cars; shortened and improved the paragraph about 806 Mobile IPv6, now with DNAv6; improved the ND text about ND 807 retransmissions with relationship to packet loss; changed the title 808 of an appendix from 'EPD' to 'Protocol Layering'; improved the 809 'Aspects introduced by OCB' appendix with a few phrases about the 810 channel use and references. 812 -30: a clarification on the reliability of ND over OCB and over 813 802.11. 815 -29: 817 o 819 -28: 821 o Created a new section 'Pseudonym Handling'. 823 o removed the 'Vehicle ID' appendix. 825 o improved the address generation from random MAC address. 827 o shortened Term IP-RSU definition. 829 o removed refs to two detail Clauses in IEEE documents, kept just 830 these latter. 832 -27: part 1 of addressing Human Rights review from IRTF. Removed 833 appendices F.2 and F.3. Shortened definition of IP-RSU. Removed 834 reference to 1609.4. A few other small changes, see diff. 836 -26: moved text from SLAAC section and from Design Considerations 837 appendix about privacy into a new Privacy Condiderations subsection 838 of the Security section; reformulated the SLAAC and IID sections to 839 stress only LLs can use EUI-64; removed the "GeoIP" wireshark 840 explanation; reformulated SLAAC and LL sections; added brief mention 841 of need of use LLs; clarified text about MAC address changes; dropped 842 pseudonym discussion; changed title of section describing examples of 843 packet formats. 845 -25: added a reference to 'IEEE Management Information Base', instead 846 of just 'Management Information Base'; added ref to further 847 appendices in the introductory phrases; improved text for IID 848 formation for SLAAC, inserting recommendation for RFC8064 before 849 RFC2464. 851 From draft-ietf-ipwave-ipv6-over-80211ocb-23 to draft-ietf-ipwave- 852 ipv6-over-80211ocb-24 854 o Nit: wrote "IPWAVE Working Group" on the front page, instead of 855 "Network Working Group". 857 o Addressed the comments on 6MAN: replaced a sentence about ND 858 problem with "is used over 802.11-OCB". 860 From draft-ietf-ipwave-ipv6-over-80211ocb-22 to draft-ietf-ipwave- 861 ipv6-over-80211ocb-23 863 o No content modifications, but check the entire draft chain on 864 IPv6-only: xml2rfc, submission on tools.ietf.org and datatracker. 866 From draft-ietf-ipwave-ipv6-over-80211ocb-21 to draft-ietf-ipwave- 867 ipv6-over-80211ocb-22 869 o Corrected typo, use dash in "802.11-OCB" instead of space. 871 o Improved the Frame Format section: MUST use QoSData, specify the 872 values within; clarified the Ethernet Adaptation Layer text. 874 From draft-ietf-ipwave-ipv6-over-80211ocb-20 to draft-ietf-ipwave- 875 ipv6-over-80211ocb-21 877 o Corrected a few nits and added names in Acknowledgments section. 879 o Removed unused reference to old Internet Draft tsvwg about QoS. 881 From draft-ietf-ipwave-ipv6-over-80211ocb-19 to draft-ietf-ipwave- 882 ipv6-over-80211ocb-20 884 o Reduced the definition of term "802.11-OCB". 886 o Left out of this specification which 802.11 header to use to 887 transmit IP packets in OCB mode (QoS Data header, Data header, or 888 any other). 890 o Added 'MUST' use an Ethernet Adaptation Layer, instead of 'is 891 using' an Ethernet Adaptation Layer. 893 From draft-ietf-ipwave-ipv6-over-80211ocb-18 to draft-ietf-ipwave- 894 ipv6-over-80211ocb-19 896 o Removed the text about fragmentation. 898 o Removed the mentioning of WSMP and GeoNetworking. 900 o Removed the explanation of the binary representation of the 901 EtherType. 903 o Rendered normative the paragraph about unicast and multicast 904 address mapping. 906 o Removed paragraph about addressing model, subnet structure and 907 easiness of using LLs. 909 o Clarified the Type/Subtype field in the 802.11 Header. 911 o Used RECOMMENDED instead of recommended, for the stable interface 912 identifiers. 914 From draft-ietf-ipwave-ipv6-over-80211ocb-17 to draft-ietf-ipwave- 915 ipv6-over-80211ocb-18 917 o Improved the MTU and fragmentation paragraph. 919 From draft-ietf-ipwave-ipv6-over-80211ocb-16 to draft-ietf-ipwave- 920 ipv6-over-80211ocb-17 922 o Susbtituted "MUST be increased" to "is increased" in the MTU 923 section, about fragmentation. 925 From draft-ietf-ipwave-ipv6-over-80211ocb-15 to draft-ietf-ipwave- 926 ipv6-over-80211ocb-16 928 o Removed the definition of the 'WiFi' term and its occurences. 929 Clarified a phrase that used it in Appendix C "Aspects introduced 930 by the OCB mode to 802.11". 932 o Added more normative words: MUST be 0x86DD, MUST fragment if size 933 larger than MTU, Sequence number in 802.11 Data header MUST be 934 increased. 936 From draft-ietf-ipwave-ipv6-over-80211ocb-14 to draft-ietf-ipwave- 937 ipv6-over-80211ocb-15 939 o Added normative term MUST in two places in section "Ethernet 940 Adaptation Layer". 942 From draft-ietf-ipwave-ipv6-over-80211ocb-13 to draft-ietf-ipwave- 943 ipv6-over-80211ocb-14 945 o Created a new Appendix titled "Extra Terminology" that contains 946 terms DSRC, DSRCS, OBU, RSU as defined outside IETF. Some of them 947 are used in the main Terminology section. 949 o Added two paragraphs explaining that ND and Mobile IPv6 have 950 problems working over 802.11-OCB, yet their adaptations is not 951 specified in this document. 953 From draft-ietf-ipwave-ipv6-over-80211ocb-12 to draft-ietf-ipwave- 954 ipv6-over-80211ocb-13 956 o Substituted "IP-OBU" for "OBRU", and "IP-RSU" for "RSRU" 957 throughout and improved OBU-related definitions in the Terminology 958 section. 960 From draft-ietf-ipwave-ipv6-over-80211ocb-11 to draft-ietf-ipwave- 961 ipv6-over-80211ocb-12 963 o Improved the appendix about "MAC Address Generation" by expressing 964 the technique to be an optional suggestion, not a mandatory 965 mechanism. 967 From draft-ietf-ipwave-ipv6-over-80211ocb-10 to draft-ietf-ipwave- 968 ipv6-over-80211ocb-11 970 o Shortened the paragraph on forming/terminating 802.11-OCB links. 972 o Moved the draft tsvwg-ieee-802-11 to Informative References. 974 From draft-ietf-ipwave-ipv6-over-80211ocb-09 to draft-ietf-ipwave- 975 ipv6-over-80211ocb-10 977 o Removed text requesting a new Group ID for multicast for OCB. 979 o Added a clarification of the meaning of value "3333" in the 980 section Address Mapping -- Multicast. 982 o Added note clarifying that in Europe the regional authority is not 983 ETSI, but "ECC/CEPT based on ENs from ETSI". 985 o Added note stating that the manner in which two STAtions set their 986 communication channel is not described in this document. 988 o Added a time qualifier to state that the "each node is represented 989 uniquely at a certain point in time." 991 o Removed text "This section may need to be moved" (the "Reliability 992 Requirements" section). This section stays there at this time. 994 o In the term definition "802.11-OCB" added a note stating that "any 995 implementation should comply with standards and regulations set in 996 the different countries for using that frequency band." 998 o In the RSU term definition, added a sentence explaining the 999 difference between RSU and RSRU: in terms of number of interfaces 1000 and IP forwarding. 1002 o Replaced "with at least two IP interfaces" with "with at least two 1003 real or virtual IP interfaces". 1005 o Added a term in the Terminology for "OBU". However the definition 1006 is left empty, as this term is defined outside IETF. 1008 o Added a clarification that it is an OBU or an OBRU in this phrase 1009 "A vehicle embarking an OBU or an OBRU". 1011 o Checked the entire document for a consistent use of terms OBU and 1012 OBRU. 1014 o Added note saying that "'p' is a letter identifying the 1015 Ammendment". 1017 o Substituted lower case for capitals SHALL or MUST in the 1018 Appendices. 1020 o Added reference to RFC7042, helpful in the 3333 explanation. 1021 Removed reference to individual submission draft-petrescu-its- 1022 scenario-reqs and added reference to draft-ietf-ipwave-vehicular- 1023 networking-survey. 1025 o Added figure captions, figure numbers, and references to figure 1026 numbers instead of 'below'. Replaced "section Section" with 1027 "section" throughout. 1029 o Minor typographical errors. 1031 From draft-ietf-ipwave-ipv6-over-80211ocb-08 to draft-ietf-ipwave- 1032 ipv6-over-80211ocb-09 1034 o Significantly shortened the Address Mapping sections, by text 1035 copied from RFC2464, and rather referring to it. 1037 o Moved the EPD description to an Appendix on its own. 1039 o Shortened the Introduction and the Abstract. 1041 o Moved the tutorial section of OCB mode introduced to .11, into an 1042 appendix. 1044 o Removed the statement that suggests that for routing purposes a 1045 prefix exchange mechanism could be needed. 1047 o Removed refs to RFC3963, RFC4429 and RFC6775; these are about ND, 1048 MIP/NEMO and oDAD; they were referred in the handover discussion 1049 section, which is out. 1051 o Updated a reference from individual submission to now a WG item in 1052 IPWAVE: the survey document. 1054 o Added term definition for WiFi. 1056 o Updated the authorship and expanded the Contributors section. 1058 o Corrected typographical errors. 1060 From draft-ietf-ipwave-ipv6-over-80211ocb-07 to draft-ietf-ipwave- 1061 ipv6-over-80211ocb-08 1063 o Removed the per-channel IPv6 prohibition text. 1065 o Corrected typographical errors. 1067 From draft-ietf-ipwave-ipv6-over-80211ocb-06 to draft-ietf-ipwave- 1068 ipv6-over-80211ocb-07 1070 o Added new terms: OBRU and RSRU ('R' for Router). Refined the 1071 existing terms RSU and OBU, which are no longer used throughout 1072 the document. 1074 o Improved definition of term "802.11-OCB". 1076 o Clarified that OCB does not "strip" security, but that the 1077 operation in OCB mode is "stripped off of all .11 security". 1079 o Clarified that theoretical OCB bandwidth speed is 54mbits, but 1080 that a commonly observed bandwidth in IP-over-OCB is 12mbit/s. 1082 o Corrected typographical errors, and improved some phrasing. 1084 From draft-ietf-ipwave-ipv6-over-80211ocb-05 to draft-ietf-ipwave- 1085 ipv6-over-80211ocb-06 1086 o Updated references of 802.11-OCB document from -2012 to the IEEE 1087 802.11-2016. 1089 o In the LL address section, and in SLAAC section, added references 1090 to 7217 opaque IIDs and 8064 stable IIDs. 1092 From draft-ietf-ipwave-ipv6-over-80211ocb-04 to draft-ietf-ipwave- 1093 ipv6-over-80211ocb-05 1095 o Lengthened the title and cleanded the abstract. 1097 o Added text suggesting LLs may be easy to use on OCB, rather than 1098 GUAs based on received prefix. 1100 o Added the risks of spoofing and hijacking. 1102 o Removed the text speculation on adoption of the TSA message. 1104 o Clarified that the ND protocol is used. 1106 o Clarified what it means "No association needed". 1108 o Added some text about how two STAs discover each other. 1110 o Added mention of external (OCB) and internal network (stable), in 1111 the subnet structure section. 1113 o Added phrase explaining that both .11 Data and .11 QoS Data 1114 headers are currently being used, and may be used in the future. 1116 o Moved the packet capture example into an Appendix Implementation 1117 Status. 1119 o Suggested moving the reliability requirements appendix out into 1120 another document. 1122 o Added a IANA Consiserations section, with content, requesting for 1123 a new multicast group "all OCB interfaces". 1125 o Added new OBU term, improved the RSU term definition, removed the 1126 ETTC term, replaced more occurences of 802.11p, 802.11-OCB with 1127 802.11-OCB. 1129 o References: 1131 * Added an informational reference to ETSI's IPv6-over- 1132 GeoNetworking. 1134 * Added more references to IETF and ETSI security protocols. 1136 * Updated some references from I-D to RFC, and from old RFC to 1137 new RFC numbers. 1139 * Added reference to multicast extensions to IPsec architecture 1140 RFC. 1142 * Added a reference to 2464-bis. 1144 * Removed FCC informative references, because not used. 1146 o Updated the affiliation of one author. 1148 o Reformulation of some phrases for better readability, and 1149 correction of typographical errors. 1151 From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave- 1152 ipv6-over-80211ocb-04 1154 o Removed a few informative references pointing to Dx draft IEEE 1155 1609 documents. 1157 o Removed outdated informative references to ETSI documents. 1159 o Added citations to IEEE 1609.2, .3 and .4-2016. 1161 o Minor textual issues. 1163 From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave- 1164 ipv6-over-80211ocb-03 1166 o Keep the previous text on multiple addresses, so remove talk about 1167 MIP6, NEMOv6 and MCoA. 1169 o Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon. 1171 o Clarified the figure showing Infrastructure mode and OCB mode side 1172 by side. 1174 o Added a reference to the IP Security Architecture RFC. 1176 o Detailed the IPv6-per-channel prohibition paragraph which reflects 1177 the discussion at the last IETF IPWAVE WG meeting. 1179 o Added section "Address Mapping -- Unicast". 1181 o Added the ".11 Trailer" to pictures of 802.11 frames. 1183 o Added text about SNAP carrying the Ethertype. 1185 o New RSU definition allowing for it be both a Router and not 1186 necessarily a Router some times. 1188 o Minor textual issues. 1190 From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave- 1191 ipv6-over-80211ocb-02 1193 o Replaced almost all occurences of 802.11p with 802.11-OCB, leaving 1194 only when explanation of evolution was necessary. 1196 o Shortened by removing parameter details from a paragraph in the 1197 Introduction. 1199 o Moved a reference from Normative to Informative. 1201 o Added text in intro clarifying there is no handover spec at IEEE, 1202 and that 1609.2 does provide security services. 1204 o Named the contents the fields of the EthernetII header (including 1205 the Ethertype bitstring). 1207 o Improved relationship between two paragraphs describing the 1208 increase of the Sequence Number in 802.11 header upon IP 1209 fragmentation. 1211 o Added brief clarification of "tracking". 1213 From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave- 1214 ipv6-over-80211ocb-01 1216 o Introduced message exchange diagram illustrating differences 1217 between 802.11 and 802.11 in OCB mode. 1219 o Introduced an appendix listing for information the set of 802.11 1220 messages that may be transmitted in OCB mode. 1222 o Removed appendix sections "Privacy Requirements", "Authentication 1223 Requirements" and "Security Certificate Generation". 1225 o Removed appendix section "Non IP Communications". 1227 o Introductory phrase in the Security Considerations section. 1229 o Improved the definition of "OCB". 1231 o Introduced theoretical stacked layers about IPv6 and IEEE layers 1232 including EPD. 1234 o Removed the appendix describing the details of prohibiting IPv6 on 1235 certain channels relevant to 802.11-OCB. 1237 o Added a brief reference in the privacy text about a precise clause 1238 in IEEE 1609.3 and .4. 1240 o Clarified the definition of a Road Side Unit. 1242 o Removed the discussion about security of WSA (because is non-IP). 1244 o Removed mentioning of the GeoNetworking discussion. 1246 o Moved references to scientific articles to a separate 'overview' 1247 draft, and referred to it. 1249 Appendix B. 802.11p 1251 The term "802.11p" is an earlier definition. The behaviour of 1252 "802.11p" networks is rolled in the document IEEE Std 802.11-2016. 1253 In that document the term 802.11p disappears. Instead, each 802.11p 1254 feature is conditioned by the IEEE Management Information Base (MIB) 1255 attribute "OCBActivated" [IEEE-802.11-2016]. Whenever OCBActivated 1256 is set to true the IEEE Std 802.11-OCB state is activated. For 1257 example, an 802.11 STAtion operating outside the context of a basic 1258 service set has the OCBActivated flag set. Such a station, when it 1259 has the flag set, uses a BSS identifier equal to ff:ff:ff:ff:ff:ff. 1261 Appendix C. Aspects introduced by the OCB mode to 802.11 1263 In the IEEE 802.11-OCB mode, all nodes in the wireless range can 1264 directly communicate with each other without involving authentication 1265 or association procedures. In OCB mode, the manner in which channels 1266 are selected and used is simplified compared to when in BSS mode. 1267 Contrary to BSS mode, at link layer, it is necessary to set 1268 statically the same channel number (or frequency) on two stations 1269 that need to communicate with each other (in BSS mode this channel 1270 set operation is performed automatically during 'scanning'). The 1271 manner in which stations set their channel number in OCB mode is not 1272 specified in this document. Stations STA1 and STA2 can exchange IP 1273 packets only if they are set on the same channel. At IP layer, they 1274 then discover each other by using the IPv6 Neighbor Discovery 1275 protocol. The allocation of a particular channel for a particular 1276 use is defined statically in standards authored by ETSI (in Europe), 1277 FCC in America, and similar organisations in South Korea, Japan and 1278 other parts of the world. 1280 Briefly, the IEEE 802.11-OCB mode has the following properties: 1282 o The use by each node of a 'wildcard' BSSID (i.e., each bit of the 1283 BSSID is set to 1) 1285 o No IEEE 802.11 Beacon frames are transmitted 1287 o No authentication is required in order to be able to communicate 1289 o No association is needed in order to be able to communicate 1291 o No encryption is provided in order to be able to communicate 1293 o Flag dot11OCBActivated is set to true 1295 All the nodes in the radio communication range (IP-OBU and IP-RSU) 1296 receive all the messages transmitted (IP-OBU and IP-RSU) within the 1297 radio communications range. The eventual conflict(s) are resolved by 1298 the MAC CDMA function. 1300 The message exchange diagram in Figure 3 illustrates a comparison 1301 between traditional 802.11 and 802.11 in OCB mode. The 'Data' 1302 messages can be IP packets such as HTTP or others. Other 802.11 1303 management and control frames (non IP) may be transmitted, as 1304 specified in the 802.11 standard. For information, the names of 1305 these messages as currently specified by the 802.11 standard are 1306 listed in Appendix G. 1308 STA AP STA1 STA2 1309 | | | | 1310 |<------ Beacon -------| |<------ Data -------->| 1311 | | | | 1312 |---- Probe Req. ----->| |<------ Data -------->| 1313 |<--- Probe Res. ------| | | 1314 | | |<------ Data -------->| 1315 |---- Auth Req. ------>| | | 1316 |<--- Auth Res. -------| |<------ Data -------->| 1317 | | | | 1318 |---- Asso Req. ------>| |<------ Data -------->| 1319 |<--- Asso Res. -------| | | 1320 | | |<------ Data -------->| 1321 |<------ Data -------->| | | 1322 |<------ Data -------->| |<------ Data -------->| 1324 (i) 802.11 Infrastructure mode (ii) 802.11-OCB mode 1326 Figure 3: Difference between messages exchanged on 802.11 (left) and 1327 802.11-OCB (right) 1329 The interface 802.11-OCB was specified in IEEE Std 802.11p (TM) -2010 1330 [IEEE-802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, 1331 titled "Amendment 6: Wireless Access in Vehicular Environments". 1332 Since then, this amendment has been integrated in IEEE 802.11(TM) 1333 -2012 and -2016 [IEEE-802.11-2016]. 1335 In document 802.11-2016, anything qualified specifically as 1336 "OCBActivated", or "outside the context of a basic service" set to be 1337 true, then it is actually referring to OCB aspects introduced to 1338 802.11. 1340 In order to delineate the aspects introduced by 802.11-OCB to 802.11, 1341 we refer to the earlier [IEEE-802.11p-2010]. The amendment is 1342 concerned with vehicular communications, where the wireless link is 1343 similar to that of Wireless LAN (using a PHY layer specified by 1344 802.11a/b/g/n), but which needs to cope with the high mobility factor 1345 inherent in scenarios of communications between moving vehicles, and 1346 between vehicles and fixed infrastructure deployed along roads. 1347 While 'p' is a letter identifying the Ammendment, just like 'a, b, g' 1348 and 'n' are, 'p' is concerned more with MAC modifications, and a 1349 little with PHY modifications; the others are mainly about PHY 1350 modifications. It is possible in practice to combine a 'p' MAC with 1351 an 'a' PHY by operating outside the context of a BSS with OFDM at 1352 5.4GHz and 5.9GHz. 1354 The 802.11-OCB links are specified to be compatible as much as 1355 possible with the behaviour of 802.11a/b/g/n and future generation 1356 IEEE WLAN links. From the IP perspective, an 802.11-OCB MAC layer 1357 offers practically the same interface to IP as the 802.11a/b/g/n and 1358 802.3. A packet sent by an IP-OBU may be received by one or multiple 1359 IP-RSUs. The link-layer resolution is performed by using the IPv6 1360 Neighbor Discovery protocol. 1362 To support this similarity statement (IPv6 is layered on top of LLC 1363 on top of 802.11-OCB, in the same way that IPv6 is layered on top of 1364 LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on 1365 top of 802.3 (for Ethernet)) it is useful to analyze the differences 1366 between 802.11-OCB and 802.11 specifications. During this analysis, 1367 we note that whereas 802.11-OCB lists relatively complex and numerous 1368 changes to the MAC layer (and very little to the PHY layer), there 1369 are only a few characteristics which may be important for an 1370 implementation transmitting IPv6 packets on 802.11-OCB links. 1372 The most important 802.11-OCB point which influences the IPv6 1373 functioning is the OCB characteristic; an additional, less direct 1374 influence, is the maximum bandwidth afforded by the PHY modulation/ 1375 demodulation methods and channel access specified by 802.11-OCB. The 1376 maximum bandwidth theoretically possible in 802.11-OCB is 54 Mbit/s 1377 (when using, for example, the following parameters: 20 MHz channel; 1378 modulation 64-QAM; coding rate R is 3/4); in practice of IP-over- 1379 802.11-OCB a commonly observed figure is 12Mbit/s; this bandwidth 1380 allows the operation of a wide range of protocols relying on IPv6. 1382 o Operation Outside the Context of a BSS (OCB): the (earlier 1383 802.11p) 802.11-OCB links are operated without a Basic Service Set 1384 (BSS). This means that the frames IEEE 802.11 Beacon, Association 1385 Request/Response, Authentication Request/Response, and similar, 1386 are not used. The used identifier of BSS (BSSID) has a 1387 hexadecimal value always 0xffffffffffff (48 '1' bits, represented 1388 as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' 1389 BSSID), as opposed to an arbitrary BSSID value set by 1390 administrator (e.g. 'My-Home-AccessPoint'). The OCB operation - 1391 namely the lack of beacon-based scanning and lack of 1392 authentication - should be taken into account when the Mobile IPv6 1393 protocol [RFC6275] and the protocols for IP layer security 1394 [RFC4301] are used. The way these protocols adapt to OCB is not 1395 described in this document. 1397 o Timing Advertisement: is a new message defined in 802.11-OCB, 1398 which does not exist in 802.11a/b/g/n. This message is used by 1399 stations to inform other stations about the value of time. It is 1400 similar to the time as delivered by a GNSS system (Galileo, GPS, 1401 ...) or by a cellular system. This message is optional for 1402 implementation. 1404 o Frequency range: this is a characteristic of the PHY layer, with 1405 almost no impact on the interface between MAC and IP. However, it 1406 is worth considering that the frequency range is regulated by a 1407 regional authority (ARCEP, ECC/CEPT based on ENs from ETSI, FCC, 1408 etc.); as part of the regulation process, specific applications 1409 are associated with specific frequency ranges. In the case of 1410 802.11-OCB, the regulator associates a set of frequency ranges, or 1411 slots within a band, to the use of applications of vehicular 1412 communications, in a band known as "5.9GHz". The 5.9GHz band is 1413 different from the 2.4GHz and 5GHz bands used by Wireless LAN. 1414 However, as with Wireless LAN, the operation of 802.11-OCB in 1415 "5.9GHz" bands is exempt from owning a license in EU (in US the 1416 5.9GHz is a licensed band of spectrum; for the fixed 1417 infrastructure an explicit FCC authorization is required; for an 1418 on-board device a 'licensed-by-rule' concept applies: rule 1419 certification conformity is required.) Technical conditions are 1420 different than those of the bands "2.4GHz" or "5GHz". The allowed 1421 power levels, and implicitly the maximum allowed distance between 1422 vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20 1423 dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum 1424 distance of approximately 1km, compared to approximately 50m. 1425 Additionally, specific conditions related to congestion avoidance, 1426 jamming avoidance, and radar detection are imposed on the use of 1427 DSRC (in US) and on the use of frequencies for Intelligent 1428 Transportation Systems (in EU), compared to Wireless LAN 1429 (802.11a/b/g/n). 1431 o 'Half-rate' encoding: as the frequency range, this parameter is 1432 related to PHY, and thus has not much impact on the interface 1433 between the IP layer and the MAC layer. 1435 o In vehicular communications using 802.11-OCB links, there are 1436 strong privacy requirements with respect to addressing. While the 1437 802.11-OCB standard does not specify anything in particular with 1438 respect to MAC addresses, in these settings there exists a strong 1439 need for dynamic change of these addresses (as opposed to the non- 1440 vehicular settings - real wall protection - where fixed MAC 1441 addresses do not currently pose some privacy risks). This is 1442 further described in Section 5. A relevant function is described 1443 in documents IEEE 1609.3-2016 [IEEE-1609.3] and IEEE 1609.4-2016 1444 [IEEE-1609.4]. 1446 Appendix D. Changes Needed on a software driver 802.11a to become a 1447 802.11-OCB driver 1449 The 802.11p amendment modifies both the 802.11 stack's physical and 1450 MAC layers but all the induced modifications can be quite easily 1451 obtained by modifying an existing 802.11a ad-hoc stack. 1453 Conditions for a 802.11a hardware to be 802.11-OCB compliant: 1455 o The PHY entity shall be an orthogonal frequency division 1456 multiplexing (OFDM) system. It must support the frequency bands 1457 on which the regulator recommends the use of ITS communications, 1458 for example using IEEE 802.11-OCB layer, in France: 5875MHz to 1459 5925MHz. 1461 o The OFDM system must provide a "half-clocked" operation using 10 1462 MHz channel spacings. 1464 o The chip transmit spectrum mask must be compliant to the "Transmit 1465 spectrum mask" from the IEEE 802.11p amendment (but experimental 1466 environments tolerate otherwise). 1468 o The chip should be able to transmit up to 44.8 dBm when used by 1469 the US government in the United States, and up to 33 dBm in 1470 Europe; other regional conditions apply. 1472 Changes needed on the network stack in OCB mode: 1474 o Physical layer: 1476 * The chip must use the Orthogonal Frequency Multiple Access 1477 (OFDM) encoding mode. 1479 * The chip must be set in half-mode rate mode (the internal clock 1480 frequency is divided by two). 1482 * The chip must use dedicated channels and should allow the use 1483 of higher emission powers. This may require modifications to 1484 the local computer file that describes regulatory domains 1485 rules, if used by the kernel to enforce local specific 1486 restrictions. Such modifications to the local computer file 1487 must respect the location-specific regulatory rules. 1489 MAC layer: 1491 * All management frames (beacons, join, leave, and others) 1492 emission and reception must be disabled except for frames of 1493 subtype Action and Timing Advertisement (defined below). 1495 * No encryption key or method must be used. 1497 * Packet emission and reception must be performed as in ad-hoc 1498 mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff). 1500 * The functions related to joining a BSS (Association Request/ 1501 Response) and for authentication (Authentication Request/Reply, 1502 Challenge) are not called. 1504 * The beacon interval is always set to 0 (zero). 1506 * Timing Advertisement frames, defined in the amendment, should 1507 be supported. The upper layer should be able to trigger such 1508 frames emission and to retrieve information contained in 1509 received Timing Advertisements. 1511 Appendix E. Protocol Layering 1513 A more theoretical and detailed view of layer stacking, and 1514 interfaces between the IP layer and 802.11-OCB layers, is illustrated 1515 in Figure 4. The IP layer operates on top of the EtherType Protocol 1516 Discrimination (EPD); this Discrimination layer is described in IEEE 1517 Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP 1518 (Link Layer Control Service Access Point). 1520 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1521 | IPv6 | 1522 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ 1523 { LLC_SAP } 802.11-OCB 1524 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary 1525 | EPD | | | 1526 | | MLME | | 1527 +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | 1528 | MAC Sublayer | | | 802.11-OCB 1529 | and ch. coord. | | SME | Services 1530 +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | 1531 | | PLME | | 1532 | PHY Layer | PLME_SAP | 1533 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1535 Figure 4: EtherType Protocol Discrimination 1537 Appendix F. Design Considerations 1539 The networks defined by 802.11-OCB are in many ways similar to other 1540 networks of the 802.11 family. In theory, the encapsulation of IPv6 1541 over 802.11-OCB could be very similar to the operation of IPv6 over 1542 other networks of the 802.11 family. However, the high mobility, 1543 strong link asymmetry and very short connection makes the 802.11-OCB 1544 link significantly different from other 802.11 networks. Also, the 1545 automotive applications have specific requirements for reliability, 1546 security and privacy, which further add to the particularity of the 1547 802.11-OCB link. 1549 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode 1551 For information, at the time of writing, this is the list of IEEE 1552 802.11 messages that may be transmitted in OCB mode, i.e. when 1553 dot11OCBActivated is true in a STA: 1555 o The STA may send management frames of subtype Action and, if the 1556 STA maintains a TSF Timer, subtype Timing Advertisement; 1558 o The STA may send control frames, except those of subtype PS-Poll, 1559 CF-End, and CF-End plus CFAck; 1561 o The STA may send data frames of subtype Data, Null, QoS Data, and 1562 QoS Null. 1564 Appendix H. Examples of Packet Formats 1566 This section describes an example of an IPv6 Packet captured over a 1567 IEEE 802.11-OCB link. 1569 By way of example we show that there is no modification in the 1570 headers when transmitted over 802.11-OCB networks - they are 1571 transmitted like any other 802.11 and Ethernet packets. 1573 We describe an experiment of capturing an IPv6 packet on an 1574 802.11-OCB link. In topology depicted in Figure 5, the packet is an 1575 IPv6 Router Advertisement. This packet is emitted by a Router on its 1576 802.11-OCB interface. The packet is captured on the Host, using a 1577 network protocol analyzer (e.g. Wireshark); the capture is performed 1578 in two different modes: direct mode and 'monitor' mode. The topology 1579 used during the capture is depicted below. 1581 The packet is captured on the Host. The Host is an IP-OBU containing 1582 an 802.11 interface in format PCI express (an ITRI product). The 1583 kernel runs the ath5k software driver with modifications for OCB 1584 mode. The capture tool is Wireshark. The file format for save and 1585 analyze is 'pcap'. The packet is generated by the Router. The 1586 Router is an IP-RSU (ITRI product). 1588 +--------+ +-------+ 1589 | | 802.11-OCB Link | | 1590 ---| Router |--------------------------------| Host | 1591 | | | | 1592 +--------+ +-------+ 1594 Figure 5: Topology for capturing IP packets on 802.11-OCB 1596 During several capture operations running from a few moments to 1597 several hours, no message relevant to the BSSID contexts were 1598 captured (no Association Request/Response, Authentication Req/Resp, 1599 Beacon). This shows that the operation of 802.11-OCB is outside the 1600 context of a BSSID. 1602 Overall, the captured message is identical with a capture of an IPv6 1603 packet emitted on a 802.11b interface. The contents are precisely 1604 similar. 1606 H.1. Capture in Monitor Mode 1608 The IPv6 RA packet captured in monitor mode is illustrated below. 1609 The radio tap header provides more flexibility for reporting the 1610 characteristics of frames. The Radiotap Header is prepended by this 1611 particular stack and operating system on the Host machine to the RA 1612 packet received from the network (the Radiotap Header is not present 1613 on the air). The implementation-dependent Radiotap Header is useful 1614 for piggybacking PHY information from the chip's registers as data in 1615 a packet understandable by userland applications using Socket 1616 interfaces (the PHY interface can be, for example: power levels, data 1617 rate, ratio of signal to noise). 1619 The packet present on the air is formed by IEEE 802.11 Data Header, 1620 Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. 1622 Radiotap Header v0 1623 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1624 |Header Revision| Header Pad | Header length | 1625 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1626 | Present flags | 1627 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1628 | Data Rate | Pad | 1629 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1631 IEEE 802.11 Data Header 1632 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1633 | Type/Subtype and Frame Ctrl | Duration | 1634 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1635 | Receiver Address... 1636 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1637 ... Receiver Address | Transmitter Address... 1638 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1639 ... Transmitter Address | 1640 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1641 | BSS Id... 1642 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1643 ... BSS Id | Frag Number and Seq Number | 1644 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1646 Logical-Link Control Header 1647 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1648 | DSAP |I| SSAP |C| Control field | Org. code... 1649 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1650 ... Organizational Code | Type | 1651 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1653 IPv6 Base Header 1654 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1655 |Version| Traffic Class | Flow Label | 1656 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1657 | Payload Length | Next Header | Hop Limit | 1658 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1659 | | 1660 + + 1661 | | 1662 + Source Address + 1663 | | 1664 + + 1665 | | 1666 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1667 | | 1668 + + 1669 | | 1670 + Destination Address + 1671 | | 1672 + + 1673 | | 1674 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1676 Router Advertisement 1677 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1678 | Type | Code | Checksum | 1679 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1680 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1681 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1682 | Reachable Time | 1683 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1684 | Retrans Timer | 1685 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1686 | Options ... 1687 +-+-+-+-+-+-+-+-+-+-+-+- 1689 The value of the Data Rate field in the Radiotap header is set to 6 1690 Mb/s. This indicates the rate at which this RA was received. 1692 The value of the Transmitter address in the IEEE 802.11 Data Header 1693 is set to a 48bit value. The value of the destination address is 1694 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS 1695 Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network 1696 protocol analyzer as being "broadcast". The Fragment number and 1697 sequence number fields are together set to 0x90C6. 1699 The value of the Organization Code field in the Logical-Link Control 1700 Header is set to 0x0, recognized as "Encapsulated Ethernet". The 1701 value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise 1702 #86DD), recognized as "IPv6". 1704 A Router Advertisement is periodically sent by the router to 1705 multicast group address ff02::1. It is an icmp packet type 134. The 1706 IPv6 Neighbor Discovery's Router Advertisement message contains an 1707 8-bit field reserved for single-bit flags, as described in [RFC4861]. 1709 The IPv6 header contains the link local address of the router 1710 (source) configured via EUI-64 algorithm, and destination address set 1711 to ff02::1. 1713 The Ethernet Type field in the logical-link control header is set to 1714 0x86dd which indicates that the frame transports an IPv6 packet. In 1715 the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 1716 which is the corresponding multicast MAC address. The BSS id is a 1717 broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link 1718 duration between vehicles and the roadside infrastructure, there is 1719 no need in IEEE 802.11-OCB to wait for the completion of association 1720 and authentication procedures before exchanging data. IEEE 1721 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) 1722 and may start communicating as soon as they arrive on the 1723 communication channel. 1725 H.2. Capture in Normal Mode 1727 The same IPv6 Router Advertisement packet described above (monitor 1728 mode) is captured on the Host, in the Normal mode, and depicted 1729 below. 1731 Ethernet II Header 1732 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1733 | Destination... 1734 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1735 ...Destination | Source... 1736 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1737 ...Source | 1738 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1739 | Type | 1740 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1742 IPv6 Base Header 1743 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1744 |Version| Traffic Class | Flow Label | 1745 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1746 | Payload Length | Next Header | Hop Limit | 1747 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1748 | | 1749 + + 1750 | | 1751 + Source Address + 1752 | | 1753 + + 1754 | | 1755 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1756 | | 1757 + + 1758 | | 1759 + Destination Address + 1760 | | 1761 + + 1762 | | 1763 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1765 Router Advertisement 1766 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1767 | Type | Code | Checksum | 1768 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1769 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1770 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1771 | Reachable Time | 1772 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1773 | Retrans Timer | 1774 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1775 | Options ... 1776 +-+-+-+-+-+-+-+-+-+-+-+- 1778 One notices that the Radiotap Header, the IEEE 802.11 Data Header and 1779 the Logical-Link Control Headers are not present. On the other hand, 1780 a new header named Ethernet II Header is present. 1782 The Destination and Source addresses in the Ethernet II header 1783 contain the same values as the fields Receiver Address and 1784 Transmitter Address present in the IEEE 802.11 Data Header in the 1785 "monitor" mode capture. 1787 The value of the Type field in the Ethernet II header is 0x86DD 1788 (recognized as "IPv6"); this value is the same value as the value of 1789 the field Type in the Logical-Link Control Header in the "monitor" 1790 mode capture. 1792 The knowledgeable experimenter will no doubt notice the similarity of 1793 this Ethernet II Header with a capture in normal mode on a pure 1794 Ethernet cable interface. 1796 An Adaptation layer is inserted on top of a pure IEEE 802.11 MAC 1797 layer, in order to adapt packets, before delivering the payload data 1798 to the applications. It adapts 802.11 LLC/MAC headers to Ethernet II 1799 headers. In further detail, this adaptation consists in the 1800 elimination of the Radiotap, 802.11 and LLC headers, and in the 1801 insertion of the Ethernet II header. In this way, IPv6 runs straight 1802 over LLC over the 802.11-OCB MAC layer; this is further confirmed by 1803 the use of the unique Type 0x86DD. 1805 Appendix I. Extra Terminology 1807 The following terms are defined outside the IETF. They are used to 1808 define the main terms in the main terminology section Section 2. 1810 DSRC (Dedicated Short Range Communication): a term defined outside 1811 the IETF. The US Federal Communications Commission (FCC) Dedicated 1812 Short Range Communication (DSRC) is defined in the Code of Federal 1813 Regulations (CFR) 47, Parts 90 and 95. This Code is referred in the 1814 definitions below. At the time of the writing of this Internet 1815 Draft, the last update of this Code was dated October 1st, 2010. 1817 DSRCS (Dedicated Short-Range Communications Services): a term defined 1818 outside the IETF. The use of radio techniques to transfer data over 1819 short distances between roadside and mobile units, between mobile 1820 units, and between portable and mobile units to perform operations 1821 related to the improvement of traffic flow, traffic safety, and other 1822 intelligent transportation service applications in a variety of 1823 environments. DSRCS systems may also transmit status and 1824 instructional messages related to the units involve. [Ref. 47 CFR 1825 90.7 - Definitions] 1826 OBU (On-Board Unit): a term defined outside the IETF. An On-Board 1827 Unit is a DSRCS transceiver that is normally mounted in or on a 1828 vehicle, or which in some instances may be a portable unit. An OBU 1829 can be operational while a vehicle or person is either mobile or 1830 stationary. The OBUs receive and contend for time to transmit on one 1831 or more radio frequency (RF) channels. Except where specifically 1832 excluded, OBU operation is permitted wherever vehicle operation or 1833 human passage is permitted. The OBUs mounted in vehicles are 1834 licensed by rule under part 95 of the respective chapter and 1835 communicate with Roadside Units (RSUs) and other OBUs. Portable OBUs 1836 are also licensed by rule under part 95 of the respective chapter. 1837 OBU operations in the Unlicensed National Information Infrastructure 1838 (UNII) Bands follow the rules in those bands. - [CFR 90.7 - 1839 Definitions]. 1841 RSU (Road-Side Unit): a term defined outside of IETF. A Roadside 1842 Unit is a DSRC transceiver that is mounted along a road or pedestrian 1843 passageway. An RSU may also be mounted on a vehicle or is hand 1844 carried, but it may only operate when the vehicle or hand- carried 1845 unit is stationary. Furthermore, an RSU operating under the 1846 respectgive part is restricted to the location where it is licensed 1847 to operate. However, portable or hand-held RSUs are permitted to 1848 operate where they do not interfere with a site-licensed operation. 1849 A RSU broadcasts data to OBUs or exchanges data with OBUs in its 1850 communications zone. An RSU also provides channel assignments and 1851 operating instructions to OBUs in its communications zone, when 1852 required. - [CFR 90.7 - Definitions]. 1854 Authors' Addresses 1856 Alexandre Petrescu 1857 CEA, LIST 1858 CEA Saclay 1859 Gif-sur-Yvette , Ile-de-France 91190 1860 France 1862 Phone: +33169089223 1863 Email: Alexandre.Petrescu@cea.fr 1865 Nabil Benamar 1866 Moulay Ismail University 1867 Morocco 1869 Phone: +212670832236 1870 Email: n.benamar@est.umi.ac.ma 1871 Jerome Haerri 1872 Eurecom 1873 Sophia-Antipolis 06904 1874 France 1876 Phone: +33493008134 1877 Email: Jerome.Haerri@eurecom.fr 1879 Jong-Hyouk Lee 1880 Sangmyung University 1881 31, Sangmyeongdae-gil, Dongnam-gu 1882 Cheonan 31066 1883 Republic of Korea 1885 Email: jonghyouk@smu.ac.kr 1887 Thierry Ernst 1888 YoGoKo 1889 France 1891 Email: thierry.ernst@yogoko.fr