idnits 2.17.1 draft-ietf-ipwave-ipv6-over-80211ocb-39.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 14, 2019) is 1832 days in the past. Is this intentional? -- Found something which looks like a code comment -- if you have code sections in the document, please surround them with '' and '' lines. Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Missing Reference: 'RFC4862' is mentioned on line 1873, but not defined == Missing Reference: 'RFC 4191' is mentioned on line 1933, but not defined ** Obsolete normative reference: RFC 2818 (Obsoleted by RFC 9110) ** Downref: Normative reference to an Informational RFC: RFC 3753 ** Downref: Normative reference to an Informational RFC: RFC 5889 ** Obsolete normative reference: RFC 7042 (Obsoleted by RFC 9542) ** Downref: Normative reference to an Informational RFC: RFC 7721 == Outdated reference: A later version (-15) exists of draft-ietf-mboned-ieee802-mcast-problems-04 Summary: 5 errors (**), 0 flaws (~~), 5 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IPWAVE Working Group A. Petrescu 3 Internet-Draft CEA, LIST 4 Intended status: Standards Track N. Benamar 5 Expires: October 16, 2019 Moulay Ismail University 6 J. Haerri 7 Eurecom 8 J. Lee 9 Sangmyung University 10 T. Ernst 11 YoGoKo 12 April 14, 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-39 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 16, 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 . . . . 28 91 Appendix D. Changes Needed on a software driver 802.11a to 92 become a 802.11-OCB driver . . . 32 93 Appendix E. Protocol Layering . . . . . . . . . . . . . . . . . 33 94 Appendix F. Design Considerations . . . . . . . . . . . . . . . 34 95 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode . . . . 34 96 Appendix H. Examples of Packet Formats . . . . . . . . . . . . . 34 97 H.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . 35 98 H.2. Capture in Normal Mode . . . . . . . . . . . . . . . . . 38 99 Appendix I. Extra Terminology . . . . . . . . . . . . . . . . . 40 100 Appendix J. Neighbor Discovery (ND) Potential Issues in Wireless 101 Links . . . . . . . . . . . . . . . . . . . . . . . 41 102 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 43 104 1. Introduction 106 This document describes the transmission of IPv6 packets on IEEE Std 107 802.11-OCB networks [IEEE-802.11-2016] (a.k.a "802.11p" see 108 Appendix B, Appendix C and Appendix D). This involves the layering 109 of IPv6 networking on top of the IEEE 802.11 MAC layer, with an LLC 110 layer. Compared to running IPv6 over the Ethernet MAC layer, there 111 is no modification expected to IEEE Std 802.11 MAC and Logical Link 112 sublayers: IPv6 works fine directly over 802.11-OCB too, with an LLC 113 layer. 115 The IPv6 network layer operates on 802.11-OCB in the same manner as 116 operating on Ethernet, but there are two kinds of exceptions: 118 o Exceptions due to different operation of IPv6 network layer on 119 802.11 than on Ethernet. To satisfy these exceptions, this 120 document describes an Ethernet Adaptation Layer between Ethernet 121 headers and 802.11 headers. The Ethernet Adaptation Layer is 122 described Section 4.2.1. The operation of IP on Ethernet is 123 described in [RFC1042], [RFC2464] . 125 o Exceptions due to the OCB nature of 802.11-OCB compared to 802.11. 126 This has impacts on security, privacy, subnet structure and 127 movement detection. For security and privacy recommendations see 128 Section 5 and Section 4.4. The subnet structure is described in 129 Section 4.6. The movement detection on OCB links is not described 130 in this document. 132 In the published literature, many documents describe aspects and 133 problems related to running IPv6 over 802.11-OCB: 134 [I-D.ietf-ipwave-vehicular-networking-survey]. 136 2. Terminology 138 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 139 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 140 "OPTIONAL" in this document are to be interpreted as described in BCP 141 14 [RFC2119] [RFC8174] when, and only when, they appear in all 142 capitals, as shown here. 144 IP-OBU (Internet Protocol On-Board Unit): an IP-OBU is a computer 145 situated in a vehicle such as an automobile, bicycle, or similar. It 146 has at least one IP interface that runs in mode OCB of 802.11, and 147 that has an "OBU" transceiver. See the definition of the term "OBU" 148 in section Appendix I. 150 IP-RSU (IP Road-Side Unit): an IP-RSU is situated along the road. It 151 has at least two distinct IP-enabled interfaces; the wireless PHY/MAC 152 layer of at least one of its IP-enabled interfaces is configured to 153 operate in 802.11-OCB mode. An IP-RSU communicates with the IP-OBU 154 in the vehicle over 802.11 wireless link operating in OCB mode. An 155 IP-RSU is similar to an Access Network Router (ANR) defined in 156 [RFC3753], and a Wireless Termination Point (WTP) defined in 157 [RFC5415]. 159 OCB (outside the context of a basic service set - BSS): A mode of 160 operation in which a STA is not a member of a BSS and does not 161 utilize IEEE Std 802.11 authentication, association, or data 162 confidentiality. 164 802.11-OCB: mode specified in IEEE Std 802.11-2016 when the MIB 165 attribute dot11OCBActivited is true. Note: compliance with standards 166 and regulations set in different countries when using the 5.9GHz 167 frequency band is required. 169 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 171 The IEEE 802.11-OCB Networks are used for vehicular communications, 172 as 'Wireless Access in Vehicular Environments'. The IP communication 173 scenarios for these environments have been described in several 174 documents; in particular, we refer the reader to 175 [I-D.ietf-ipwave-vehicular-networking-survey], that lists some 176 scenarios and requirements for IP in Intelligent Transportation 177 Systems. 179 The link model is the following: STA --- 802.11-OCB --- STA. In 180 vehicular networks, STAs can be IP-RSUs and/or IP-OBUs. While 181 802.11-OCB is clearly specified, and the use of IPv6 over such link 182 is not radically new, the operating environment (vehicular networks) 183 brings in new perspectives. 185 4. IPv6 over 802.11-OCB 187 4.1. Maximum Transmission Unit (MTU) 189 The default MTU for IP packets on 802.11-OCB MUST be 1500 octets. It 190 is the same value as IPv6 packets on Ethernet links, as specified in 191 [RFC2464]. This value of the MTU respects the recommendation that 192 every link on the Internet must have a minimum MTU of 1280 octets 193 (stated in [RFC8200], and the recommendations therein, especially 194 with respect to fragmentation). 196 4.2. Frame Format 198 IP packets MUST be transmitted over 802.11-OCB media as QoS Data 199 frames whose format is specified in IEEE 802.11(TM) -2016 200 [IEEE-802.11-2016]. 202 The IPv6 packet transmitted on 802.11-OCB MUST be immediately 203 preceded by a Logical Link Control (LLC) header and an 802.11 header. 204 In the LLC header, and in accordance with the EtherType Protocol 205 Discrimination (EPD, see Appendix E), the value of the Type field 206 MUST be set to 0x86DD (IPv6). In the 802.11 header, the value of the 207 Subtype sub-field in the Frame Control field MUST be set to 8 (i.e. 208 'QoS Data'); the value of the Traffic Identifier (TID) sub-field of 209 the QoS Control field of the 802.11 header MUST be set to binary 001 210 (i.e. User Priority 'Background', QoS Access Category 'AC_BK'). 212 To simplify the Application Programming Interface (API) between the 213 operating system and the 802.11-OCB media, device drivers MAY 214 implement an Ethernet Adaptation Layer that translates Ethernet II 215 frames to the 802.11 format and vice versa. An Ethernet Adaptation 216 Layer is described in Section 4.2.1. 218 4.2.1. Ethernet Adaptation Layer 220 An 'adaptation' layer is inserted between a MAC layer and the 221 Networking layer. This is used to transform some parameters between 222 their form expected by the IP stack and the form provided by the MAC 223 layer. 225 An Ethernet Adaptation Layer makes an 802.11 MAC look to IP 226 Networking layer as a more traditional Ethernet layer. At reception, 227 this layer takes as input the IEEE 802.11 header and the Logical-Link 228 Layer Control Header and produces an Ethernet II Header. At sending, 229 the reverse operation is performed. 231 The operation of the Ethernet Adaptation Layer is depicted by the 232 double arrow in Figure 1. 234 +------------------+------------+-------------+---------+-----------+ 235 | 802.11 header | LLC Header | IPv6 Header | Payload |.11 Trailer| 236 +------------------+------------+-------------+---------+-----------+ 237 \ / \ / 238 --------------------------- -------- 239 \---------------------------------------------/ 240 ^ 241 | 242 802.11-to-Ethernet Adaptation Layer 243 | 244 v 245 +---------------------+-------------+---------+ 246 | Ethernet II Header | IPv6 Header | Payload | 247 +---------------------+-------------+---------+ 249 Figure 1: Operation of the Ethernet Adaptation Layer 251 The Receiver and Transmitter Address fields in the 802.11 header MUST 252 contain the same values as the Destination and the Source Address 253 fields in the Ethernet II Header, respectively. The value of the 254 Type field in the LLC Header MUST be the same as the value of the 255 Type field in the Ethernet II Header. That value MUST be set to 256 0x86DD (IPv6). 258 The ".11 Trailer" contains solely a 4-byte Frame Check Sequence. 260 The placement of IPv6 networking layer on Ethernet Adaptation Layer 261 is illustrated in Figure 2. 263 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 264 | IPv6 | 265 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 266 | Ethernet Adaptation Layer | 267 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 268 | 802.11 MAC | 269 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 270 | 802.11 PHY | 271 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 273 Figure 2: Ethernet Adaptation Layer stacked with other layers 275 (in the above figure, a 802.11 profile is represented; this is used 276 also for 802.11-OCB profile.) 278 4.3. Link-Local Addresses 280 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 281 MAY be assigned to an 802.11-OCB interface. Among these types of 282 addresses only the IPv6 link-local addresses MAY be formed using an 283 EUI-64 identifier, in particular during transition time. 285 If the IPv6 link-local address is formed using an EUI-64 identifier, 286 then the mechanism of forming that address is the same mechanism as 287 used to form an IPv6 link-local address on Ethernet links. This 288 mechanism is described in section 5 of [RFC2464]. 290 4.4. Stateless Autoconfiguration 292 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 293 MAY be assigned to an 802.11-OCB interface. This section describes 294 the formation of Interface Identifiers for IPv6 addresses of type 295 'Global' or 'Unique Local'. For Interface Identifiers for IPv6 296 address of type 'Link-Local' see Section 4.3. 298 The Interface Identifier for an 802.11-OCB interface is formed using 299 the same rules as the Interface Identifier for an Ethernet interface; 300 the RECOMMENDED method for forming stable Interface Identifiers 301 (IIDs) is described in [RFC8064]. The method of forming IIDs 302 described in section 4 of [RFC2464] MAY be used during transition 303 time, in particular for IPv6 link-local addresses. 305 The bits in the Interface Identifier have no generic meaning and the 306 identifier should be treated as an opaque value. The bits 307 'Universal' and 'Group' in the identifier of an 802.11-OCB interface 308 are significant, as this is an IEEE link-layer address. The details 309 of this significance are described in [RFC7136]. 311 Semantically opaque Interface Identifiers, instead of meaningful 312 Interface Identifiers derived from a valid and meaningful MAC address 313 ([RFC2464], section 4), help avoid certain privacy risks (see the 314 risks mentioned in Section 5.1.1). If semantically opaque Interface 315 Identifiers are needed, they MAY be generated using the method for 316 generating semantically opaque Interface Identifiers with IPv6 317 Stateless Address Autoconfiguration given in [RFC7217]. Typically, 318 an opaque Interface Identifier is formed starting from identifiers 319 different than the MAC addresses, and from cryptographically strong 320 material. Thus, privacy sensitive information is absent from 321 Interface IDs, because it is impossible to calculate back the initial 322 value from which the Interface ID was first generated (intuitively, 323 it is as hard as mentally finding the square root of a number, and as 324 impossible as trying to use computers to identify quickly whether a 325 large number is prime). 327 Some applications that use IPv6 packets on 802.11-OCB links (among 328 other link types) may benefit from IPv6 addresses whose Interface 329 Identifiers don't change too often. It is RECOMMENDED to use the 330 mechanisms described in RFC 7217 to permit the use of Stable 331 Interface Identifiers that do not change within one subnet prefix. A 332 possible source for the Net-Iface Parameter is a virtual interface 333 name, or logical interface name, that is decided by a local 334 administrator. 336 4.5. Address Mapping 338 Unicast and multicast address mapping MUST follow the procedures 339 specified for Ethernet interfaces in sections 6 and 7 of [RFC2464]. 341 4.5.1. Address Mapping -- Unicast 343 The procedure for mapping IPv6 unicast addresses into Ethernet link- 344 layer addresses is described in [RFC4861]. 346 4.5.2. Address Mapping -- Multicast 348 The multicast address mapping is performed according to the method 349 specified in section 7 of [RFC2464]. The meaning of the value "3333" 350 mentioned in that section 7 of [RFC2464] is defined in section 2.3.1 351 of [RFC7042]. 353 Transmitting IPv6 packets to multicast destinations over 802.11 links 354 proved to have some performance issues 355 [I-D.ietf-mboned-ieee802-mcast-problems]. These issues may be 356 exacerbated in OCB mode. Solutions for these problems SHOULD 357 consider the OCB mode of operation. 359 4.6. Subnet Structure 361 A subnet is formed by the external 802.11-OCB interfaces of vehicles 362 that are in close range (not by their in-vehicle interfaces). This 363 subnet MUST use at least the link-local prefix and the interfaces 364 MUST be assigned IPv6 address(es) of type link-local. All nodes in 365 the subnet MUST be able to communicate directly using their link- 366 local unicast addresses. 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 baseline Neighbor Discovery protocol (ND) [RFC4861] MUST be used 389 over 802.11-OCB links. Transmitting ND packets may prove to have 390 some performance issues. These issues may be exacerbated in OCB 391 mode. Solutions for these problems SHOULD consider the OCB mode of 392 operation. The best of current knowledge indicates the kinds of 393 issues that may arise with ND in OCB mode; they are described in 394 Appendix J. 396 Protocols like Mobile IPv6 [RFC6275] and DNAv6 [RFC6059], which 397 depend on timely movement detection, might need additional tuning 398 work to handle the lack of link-layer notifications during handover. 399 This is for further study. 401 5. Security Considerations 403 Any security mechanism at the IP layer or above that may be carried 404 out for the general case of IPv6 may also be carried out for IPv6 405 operating over 802.11-OCB. 407 The OCB operation is stripped off of all existing 802.11 link-layer 408 security mechanisms. There is no encryption applied below the 409 network layer running on 802.11-OCB. At application layer, the IEEE 410 1609.2 document [IEEE-1609.2] does provide security services for 411 certain applications to use; application-layer mechanisms are out-of- 412 scope of this document. On another hand, a security mechanism 413 provided at networking layer, such as IPsec [RFC4301], may provide 414 data security protection to a wider range of applications. 416 802.11-OCB does not provide any cryptographic protection, because it 417 operates outside the context of a BSS (no Association Request/ 418 Response, no Challenge messages). Any attacker can therefore just 419 sit in the near range of vehicles, sniff the network (just set the 420 interface card's frequency to the proper range) and perform attacks 421 without needing to physically break any wall. Such a link is less 422 protected than commonly used links (wired link or protected 802.11). 424 The potential attack vectors are: MAC address spoofing, IP address 425 and session hijacking, and privacy violation Section 5.1. 427 Within the IPsec Security Architecture [RFC4301], the IPsec AH and 428 ESP headers [RFC4302] and [RFC4303] respectively, its multicast 429 extensions [RFC5374], HTTPS [RFC2818] and SeND [RFC3971] protocols 430 can be used to protect communications. Further, the assistance of 431 proper Public Key Infrastructure (PKI) protocols [RFC4210] is 432 necessary to establish credentials. More IETF protocols are 433 available in the toolbox of the IP security protocol designer. 434 Certain ETSI protocols related to security protocols in Intelligent 435 Transportation Systems are described in [ETSI-sec-archi]. 437 5.1. Privacy Considerations 439 As with all Ethernet and 802.11 interface identifiers ([RFC7721]), 440 the identifier of an 802.11-OCB interface may involve privacy, MAC 441 address spoofing and IP address hijacking risks. A vehicle embarking 442 an IP-OBU whose egress interface is 802.11-OCB may expose itself to 443 eavesdropping and subsequent correlation of data; this may reveal 444 data considered private by the vehicle owner; there is a risk of 445 being tracked. In outdoors public environments, where vehicles 446 typically circulate, the privacy risks are more important than in 447 indoors settings. It is highly likely that attacker sniffers are 448 deployed along routes which listen for IEEE frames, including IP 449 packets, of vehicles passing by. For this reason, in the 802.11-OCB 450 deployments, there is a strong necessity to use protection tools such 451 as dynamically changing MAC addresses Section 5.2, semantically 452 opaque Interface Identifiers and stable Interface Identifiers 453 Section 4.4. This may help mitigate privacy risks to a certain 454 level. 456 5.1.1. Privacy Risks of Meaningful info in Interface IDs 458 The privacy risks of using MAC addresses displayed in Interface 459 Identifiers are important. The IPv6 packets can be captured easily 460 in the Internet and on-link in public roads. For this reason, an 461 attacker may realize many attacks on privacy. One such attack on 462 802.11-OCB is to capture, store and correlate Company ID information 463 present in MAC addresses of many cars (e.g. listen for Router 464 Advertisements, or other IPv6 application data packets, and record 465 the value of the source address in these packets). Further 466 correlation of this information with other data captured by other 467 means, or other visual information (car color, others) MAY constitute 468 privacy risks. 470 5.2. MAC Address and Interface ID Generation 472 In 802.11-OCB networks, the MAC addresses MAY change during well 473 defined renumbering events. In the moment the MAC address is changed 474 on an 802.11-OCB interface all the Interface Identifiers of IPv6 475 addresses assigned to that interface MUST change. 477 The policy dictating when the MAC address is changed on the 478 802.11-OCB interface is to-be-determined. For more information on 479 the motivation of this policy please refer to the privacy discussion 480 in Appendix C. 482 A 'randomized' MAC address has the following characteristics: 484 o Bit "Local/Global" set to "locally admninistered". 486 o Bit "Unicast/Multicast" set to "Unicast". 488 o The 46 remaining bits are set to a random value, using a random 489 number generator that meets the requirements of [RFC4086]. 491 To meet the randomization requirements for the 46 remaining bits, a 492 hash function may be used. For example, the SHA256 hash function may 493 be used with input a 256 bit local secret, the 'nominal' MAC Address 494 of the interface, and a representation of the date and time of the 495 renumbering event. 497 A randomized Interface ID has the same characteristics of a 498 randomized MAC address, except the length in bits. A MAC address 499 SHOULD be of length 48 decimal. An Interface ID SHOULD be of length 500 64 decimal for all types of IPv6 addresses. In the particular case 501 of IPv6 link-local addresses, the length of the Interface ID MAY be 502 118 decimal. 504 5.3. Pseudonym Handling 506 The demand for privacy protection of vehicles' and drivers' 507 identities, which could be granted by using a pseudonym or alias 508 identity at the same time, may hamper the required confidentiality of 509 messages and trust between participants - especially in safety 510 critical vehicular communication. 512 o Particular challenges arise when the pseudonymization mechanism 513 used relies on (randomized) re-addressing. 515 o A proper pseudonymization tool operated by a trusted third party 516 may be needed to ensure both aspects simultaneously (privacy 517 protection on one hand and trust between participants on another 518 hand). 520 o This is discussed in Section 4.4 and Section 5 of this document. 522 o Pseudonymity is also discussed in 523 [I-D.ietf-ipwave-vehicular-networking-survey] in its sections 524 4.2.4 and 5.1.2. 526 6. IANA Considerations 528 No request to IANA. 530 7. Contributors 532 Christian Huitema, Tony Li. 534 Romain Kuntz contributed extensively about IPv6 handovers between 535 links running outside the context of a BSS (802.11-OCB links). 537 Tim Leinmueller contributed the idea of the use of IPv6 over 538 802.11-OCB for distribution of certificates. 540 Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey 541 Voronov provided significant feedback on the experience of using IP 542 messages over 802.11-OCB in initial trials. 544 Michelle Wetterwald contributed extensively the MTU discussion, 545 offered the ETSI ITS perspective, and reviewed other parts of the 546 document. 548 8. Acknowledgements 550 The authors would like to thank Witold Klaudel, Ryuji Wakikawa, 551 Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan 552 Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray 553 Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, 554 Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne, 555 Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark, 556 Bob Moskowitz, Andrew Dryden, Georg Mayer, Dorothy Stanley, Sandra 557 Cespedes, Mariano Falcitelli, Sri Gundavelli, Abdussalam Baryun, 558 Margaret Cullen, Erik Kline, Carlos Jesus Bernardos Cano, Ronald in 559 't Velt, Katrin Sjoberg, Roland Bless, Tijink Jasja, Kevin Smith, 560 Brian Carpenter, Julian Reschke, Mikael Abrahamsson, Dirk von Hugo, 561 Lorenzo Colitti, Pascal Thubert, Ole Troan, Jinmei Tatuya and William 562 Whyte. Their valuable comments clarified particular issues and 563 generally helped to improve the document. 565 Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB 566 drivers for linux and described how. 568 For the multicast discussion, the authors would like to thank Owen 569 DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and 570 participants to discussions in network working groups. 572 The authors would like to thank participants to the Birds-of- 573 a-Feather "Intelligent Transportation Systems" meetings held at IETF 574 in 2016. 576 Human Rights Protocol Considerations review by Amelia Andersdotter. 578 9. References 580 9.1. Normative References 582 [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission 583 of IP datagrams over IEEE 802 networks", STD 43, RFC 1042, 584 DOI 10.17487/RFC1042, February 1988, 585 . 587 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 588 Requirement Levels", BCP 14, RFC 2119, 589 DOI 10.17487/RFC2119, March 1997, 590 . 592 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 593 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 594 . 596 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 597 DOI 10.17487/RFC2818, May 2000, 598 . 600 [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related 601 Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, 602 . 604 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 605 "SEcure Neighbor Discovery (SEND)", RFC 3971, 606 DOI 10.17487/RFC3971, March 2005, 607 . 609 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 610 "Randomness Requirements for Security", BCP 106, RFC 4086, 611 DOI 10.17487/RFC4086, June 2005, 612 . 614 [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast 615 Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005, 616 . 618 [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, 619 "Internet X.509 Public Key Infrastructure Certificate 620 Management Protocol (CMP)", RFC 4210, 621 DOI 10.17487/RFC4210, September 2005, 622 . 624 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 625 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 626 2006, . 628 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 629 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 630 December 2005, . 632 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 633 DOI 10.17487/RFC4302, December 2005, 634 . 636 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 637 RFC 4303, DOI 10.17487/RFC4303, December 2005, 638 . 640 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 641 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 642 DOI 10.17487/RFC4861, September 2007, 643 . 645 [RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast 646 Extensions to the Security Architecture for the Internet 647 Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008, 648 . 650 [RFC5415] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, 651 Ed., "Control And Provisioning of Wireless Access Points 652 (CAPWAP) Protocol Specification", RFC 5415, 653 DOI 10.17487/RFC5415, March 2009, 654 . 656 [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing 657 Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889, 658 September 2010, . 660 [RFC6059] Krishnan, S. and G. Daley, "Simple Procedures for 661 Detecting Network Attachment in IPv6", RFC 6059, 662 DOI 10.17487/RFC6059, November 2010, 663 . 665 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 666 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 667 2011, . 669 [RFC7042] Eastlake 3rd, D. and J. Abley, "IANA Considerations and 670 IETF Protocol and Documentation Usage for IEEE 802 671 Parameters", BCP 141, RFC 7042, DOI 10.17487/RFC7042, 672 October 2013, . 674 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 675 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 676 February 2014, . 678 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 679 Interface Identifiers with IPv6 Stateless Address 680 Autoconfiguration (SLAAC)", RFC 7217, 681 DOI 10.17487/RFC7217, April 2014, 682 . 684 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 685 Considerations for IPv6 Address Generation Mechanisms", 686 RFC 7721, DOI 10.17487/RFC7721, March 2016, 687 . 689 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 690 "Recommendation on Stable IPv6 Interface Identifiers", 691 RFC 8064, DOI 10.17487/RFC8064, February 2017, 692 . 694 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 695 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 696 May 2017, . 698 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 699 (IPv6) Specification", STD 86, RFC 8200, 700 DOI 10.17487/RFC8200, July 2017, 701 . 703 9.2. Informative References 705 [ETSI-sec-archi] 706 "ETSI TS 102 940 V1.2.1 (2016-11), ETSI Technical 707 Specification, Intelligent Transport Systems (ITS); 708 Security; ITS communications security architecture and 709 security management, November 2016. Downloaded on 710 September 9th, 2017, freely available from ETSI website at 711 URL http://www.etsi.org/deliver/ 712 etsi_ts/102900_102999/102940/01.02.01_60/ 713 ts_102940v010201p.pdf". 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; the document itself is also freely 756 available, but with some difficulty (requires 757 registration); description and document retrieved on April 758 8th, 2019, starting from URL 759 https://standards.ieee.org/findstds/ 760 standard/802.11-2016.html". 762 [IEEE-802.11p-2010] 763 "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information 764 Technology - Telecommunications and information exchange 765 between systems - Local and metropolitan area networks - 766 Specific requirements, Part 11: Wireless LAN Medium Access 767 Control (MAC) and Physical Layer (PHY) Specifications, 768 Amendment 6: Wireless Access in Vehicular Environments; 769 document freely available at URL 770 http://standards.ieee.org/getieee802/ 771 download/802.11p-2010.pdf retrieved on September 20th, 772 2013.". 774 Appendix A. ChangeLog 776 The changes are listed in reverse chronological order, most recent 777 changes appearing at the top of the list. 779 -39: removed a reference to an expired draft trying to update the 780 IPv6-over-Ethernet spec 'RFC2464bis'; added text in the subnet 781 structure section saying nodes MUST be able to communicate directly 782 using their link-local addresses. 784 -38: removed the word "fe80::/10". 786 -37: added a section about issues on ND wireless; added the qualifier 787 'baseline' to using ND on 802.11-OCB; improved the description of the 788 reference to 802.11-2016 document, with a qualifier about the 789 difficulty of accessing it, even though it is free. 791 -36: removed a phrase about the IID formation and MAC generation, but 792 left in the section 5.2 that describes how it happens. 794 -35: addressing the the intarea review: clarified a small apparent 795 contradiction between two parts of text that use the old MAC-based 796 IIDs (clarified by using qualifiers from each other: transition time, 797 and ll addresses); sequenced closer the LL and Stateless Autoconf 798 sections, instead of spacing them; shortened the paragraph of Opaque 799 IIDs; moved the privacy risks of in-clear IIDs in the security 800 section; removed a short phrase duplicating the idea of privacy 801 risks; added third time a reference to the 802.11-2016 document; used 802 'the hidden terminal' text; updated the Terminology section with new 803 BCP-14 text 'MUST' to include RFC8174. 805 -33: substituted 'movement detection' for 'handover behaviour' in 806 introductory text; removed redundant phrase referring to Security 807 Considerations section; removed the phrase about forming mechanisms 808 being left out, as IP is not much concerned about L2 forming; moved 809 the Pseudonym section from main section to end of Security 810 Considerations section (and clarified 'concurrently'); capitalized 811 SHOULD consider OCB in WiFi multicast problems, and referred to more 812 recent I-D on topic; removed several phrases in a paragraph about 813 oui.txt and MAC presence in IPv6 address, as they are well known 814 info, but clarified the example of privacy risk of Company ID in MAC 815 addresses in public roads; clarified that ND MUST be used over 816 802.11-OCB. 818 -32: significantly shortened the relevant ND/OCB paragraph. It now 819 just states ND is used over OCB, w/o detailing. 821 -31: filled in the section titled "Pseudonym Handling"; removed a 822 'MAY NOT' phrase about possibility of having other prefix than the LL 823 on the link between cars; shortened and improved the paragraph about 824 Mobile IPv6, now with DNAv6; improved the ND text about ND 825 retransmissions with relationship to packet loss; changed the title 826 of an appendix from 'EPD' to 'Protocol Layering'; improved the 827 'Aspects introduced by OCB' appendix with a few phrases about the 828 channel use and references. 830 -30: a clarification on the reliability of ND over OCB and over 831 802.11. 833 -29: 835 o 837 -28: 839 o Created a new section 'Pseudonym Handling'. 841 o removed the 'Vehicle ID' appendix. 843 o improved the address generation from random MAC address. 845 o shortened Term IP-RSU definition. 847 o removed refs to two detail Clauses in IEEE documents, kept just 848 these latter. 850 -27: part 1 of addressing Human Rights review from IRTF. Removed 851 appendices F.2 and F.3. Shortened definition of IP-RSU. Removed 852 reference to 1609.4. A few other small changes, see diff. 854 -26: moved text from SLAAC section and from Design Considerations 855 appendix about privacy into a new Privacy Condiderations subsection 856 of the Security section; reformulated the SLAAC and IID sections to 857 stress only LLs can use EUI-64; removed the "GeoIP" wireshark 858 explanation; reformulated SLAAC and LL sections; added brief mention 859 of need of use LLs; clarified text about MAC address changes; dropped 860 pseudonym discussion; changed title of section describing examples of 861 packet formats. 863 -25: added a reference to 'IEEE Management Information Base', instead 864 of just 'Management Information Base'; added ref to further 865 appendices in the introductory phrases; improved text for IID 866 formation for SLAAC, inserting recommendation for RFC8064 before 867 RFC2464. 869 From draft-ietf-ipwave-ipv6-over-80211ocb-23 to draft-ietf-ipwave- 870 ipv6-over-80211ocb-24 872 o Nit: wrote "IPWAVE Working Group" on the front page, instead of 873 "Network Working Group". 875 o Addressed the comments on 6MAN: replaced a sentence about ND 876 problem with "is used over 802.11-OCB". 878 From draft-ietf-ipwave-ipv6-over-80211ocb-22 to draft-ietf-ipwave- 879 ipv6-over-80211ocb-23 881 o No content modifications, but check the entire draft chain on 882 IPv6-only: xml2rfc, submission on tools.ietf.org and datatracker. 884 From draft-ietf-ipwave-ipv6-over-80211ocb-21 to draft-ietf-ipwave- 885 ipv6-over-80211ocb-22 887 o Corrected typo, use dash in "802.11-OCB" instead of space. 889 o Improved the Frame Format section: MUST use QoSData, specify the 890 values within; clarified the Ethernet Adaptation Layer text. 892 From draft-ietf-ipwave-ipv6-over-80211ocb-20 to draft-ietf-ipwave- 893 ipv6-over-80211ocb-21 895 o Corrected a few nits and added names in Acknowledgments section. 897 o Removed unused reference to old Internet Draft tsvwg about QoS. 899 From draft-ietf-ipwave-ipv6-over-80211ocb-19 to draft-ietf-ipwave- 900 ipv6-over-80211ocb-20 902 o Reduced the definition of term "802.11-OCB". 904 o Left out of this specification which 802.11 header to use to 905 transmit IP packets in OCB mode (QoS Data header, Data header, or 906 any other). 908 o Added 'MUST' use an Ethernet Adaptation Layer, instead of 'is 909 using' an Ethernet Adaptation Layer. 911 From draft-ietf-ipwave-ipv6-over-80211ocb-18 to draft-ietf-ipwave- 912 ipv6-over-80211ocb-19 914 o Removed the text about fragmentation. 916 o Removed the mentioning of WSMP and GeoNetworking. 918 o Removed the explanation of the binary representation of the 919 EtherType. 921 o Rendered normative the paragraph about unicast and multicast 922 address mapping. 924 o Removed paragraph about addressing model, subnet structure and 925 easiness of using LLs. 927 o Clarified the Type/Subtype field in the 802.11 Header. 929 o Used RECOMMENDED instead of recommended, for the stable interface 930 identifiers. 932 From draft-ietf-ipwave-ipv6-over-80211ocb-17 to draft-ietf-ipwave- 933 ipv6-over-80211ocb-18 935 o Improved the MTU and fragmentation paragraph. 937 From draft-ietf-ipwave-ipv6-over-80211ocb-16 to draft-ietf-ipwave- 938 ipv6-over-80211ocb-17 939 o Susbtituted "MUST be increased" to "is increased" in the MTU 940 section, about fragmentation. 942 From draft-ietf-ipwave-ipv6-over-80211ocb-15 to draft-ietf-ipwave- 943 ipv6-over-80211ocb-16 945 o Removed the definition of the 'WiFi' term and its occurences. 946 Clarified a phrase that used it in Appendix C "Aspects introduced 947 by the OCB mode to 802.11". 949 o Added more normative words: MUST be 0x86DD, MUST fragment if size 950 larger than MTU, Sequence number in 802.11 Data header MUST be 951 increased. 953 From draft-ietf-ipwave-ipv6-over-80211ocb-14 to draft-ietf-ipwave- 954 ipv6-over-80211ocb-15 956 o Added normative term MUST in two places in section "Ethernet 957 Adaptation Layer". 959 From draft-ietf-ipwave-ipv6-over-80211ocb-13 to draft-ietf-ipwave- 960 ipv6-over-80211ocb-14 962 o Created a new Appendix titled "Extra Terminology" that contains 963 terms DSRC, DSRCS, OBU, RSU as defined outside IETF. Some of them 964 are used in the main Terminology section. 966 o Added two paragraphs explaining that ND and Mobile IPv6 have 967 problems working over 802.11-OCB, yet their adaptations is not 968 specified in this document. 970 From draft-ietf-ipwave-ipv6-over-80211ocb-12 to draft-ietf-ipwave- 971 ipv6-over-80211ocb-13 973 o Substituted "IP-OBU" for "OBRU", and "IP-RSU" for "RSRU" 974 throughout and improved OBU-related definitions in the Terminology 975 section. 977 From draft-ietf-ipwave-ipv6-over-80211ocb-11 to draft-ietf-ipwave- 978 ipv6-over-80211ocb-12 980 o Improved the appendix about "MAC Address Generation" by expressing 981 the technique to be an optional suggestion, not a mandatory 982 mechanism. 984 From draft-ietf-ipwave-ipv6-over-80211ocb-10 to draft-ietf-ipwave- 985 ipv6-over-80211ocb-11 986 o Shortened the paragraph on forming/terminating 802.11-OCB links. 988 o Moved the draft tsvwg-ieee-802-11 to Informative References. 990 From draft-ietf-ipwave-ipv6-over-80211ocb-09 to draft-ietf-ipwave- 991 ipv6-over-80211ocb-10 993 o Removed text requesting a new Group ID for multicast for OCB. 995 o Added a clarification of the meaning of value "3333" in the 996 section Address Mapping -- Multicast. 998 o Added note clarifying that in Europe the regional authority is not 999 ETSI, but "ECC/CEPT based on ENs from ETSI". 1001 o Added note stating that the manner in which two STAtions set their 1002 communication channel is not described in this document. 1004 o Added a time qualifier to state that the "each node is represented 1005 uniquely at a certain point in time." 1007 o Removed text "This section may need to be moved" (the "Reliability 1008 Requirements" section). This section stays there at this time. 1010 o In the term definition "802.11-OCB" added a note stating that "any 1011 implementation should comply with standards and regulations set in 1012 the different countries for using that frequency band." 1014 o In the RSU term definition, added a sentence explaining the 1015 difference between RSU and RSRU: in terms of number of interfaces 1016 and IP forwarding. 1018 o Replaced "with at least two IP interfaces" with "with at least two 1019 real or virtual IP interfaces". 1021 o Added a term in the Terminology for "OBU". However the definition 1022 is left empty, as this term is defined outside IETF. 1024 o Added a clarification that it is an OBU or an OBRU in this phrase 1025 "A vehicle embarking an OBU or an OBRU". 1027 o Checked the entire document for a consistent use of terms OBU and 1028 OBRU. 1030 o Added note saying that "'p' is a letter identifying the 1031 Ammendment". 1033 o Substituted lower case for capitals SHALL or MUST in the 1034 Appendices. 1036 o Added reference to RFC7042, helpful in the 3333 explanation. 1037 Removed reference to individual submission draft-petrescu-its- 1038 scenario-reqs and added reference to draft-ietf-ipwave-vehicular- 1039 networking-survey. 1041 o Added figure captions, figure numbers, and references to figure 1042 numbers instead of 'below'. Replaced "section Section" with 1043 "section" throughout. 1045 o Minor typographical errors. 1047 From draft-ietf-ipwave-ipv6-over-80211ocb-08 to draft-ietf-ipwave- 1048 ipv6-over-80211ocb-09 1050 o Significantly shortened the Address Mapping sections, by text 1051 copied from RFC2464, and rather referring to it. 1053 o Moved the EPD description to an Appendix on its own. 1055 o Shortened the Introduction and the Abstract. 1057 o Moved the tutorial section of OCB mode introduced to .11, into an 1058 appendix. 1060 o Removed the statement that suggests that for routing purposes a 1061 prefix exchange mechanism could be needed. 1063 o Removed refs to RFC3963, RFC4429 and RFC6775; these are about ND, 1064 MIP/NEMO and oDAD; they were referred in the handover discussion 1065 section, which is out. 1067 o Updated a reference from individual submission to now a WG item in 1068 IPWAVE: the survey document. 1070 o Added term definition for WiFi. 1072 o Updated the authorship and expanded the Contributors section. 1074 o Corrected typographical errors. 1076 From draft-ietf-ipwave-ipv6-over-80211ocb-07 to draft-ietf-ipwave- 1077 ipv6-over-80211ocb-08 1079 o Removed the per-channel IPv6 prohibition text. 1081 o Corrected typographical errors. 1083 From draft-ietf-ipwave-ipv6-over-80211ocb-06 to draft-ietf-ipwave- 1084 ipv6-over-80211ocb-07 1086 o Added new terms: OBRU and RSRU ('R' for Router). Refined the 1087 existing terms RSU and OBU, which are no longer used throughout 1088 the document. 1090 o Improved definition of term "802.11-OCB". 1092 o Clarified that OCB does not "strip" security, but that the 1093 operation in OCB mode is "stripped off of all .11 security". 1095 o Clarified that theoretical OCB bandwidth speed is 54mbits, but 1096 that a commonly observed bandwidth in IP-over-OCB is 12mbit/s. 1098 o Corrected typographical errors, and improved some phrasing. 1100 From draft-ietf-ipwave-ipv6-over-80211ocb-05 to draft-ietf-ipwave- 1101 ipv6-over-80211ocb-06 1103 o Updated references of 802.11-OCB document from -2012 to the IEEE 1104 802.11-2016. 1106 o In the LL address section, and in SLAAC section, added references 1107 to 7217 opaque IIDs and 8064 stable IIDs. 1109 From draft-ietf-ipwave-ipv6-over-80211ocb-04 to draft-ietf-ipwave- 1110 ipv6-over-80211ocb-05 1112 o Lengthened the title and cleanded the abstract. 1114 o Added text suggesting LLs may be easy to use on OCB, rather than 1115 GUAs based on received prefix. 1117 o Added the risks of spoofing and hijacking. 1119 o Removed the text speculation on adoption of the TSA message. 1121 o Clarified that the ND protocol is used. 1123 o Clarified what it means "No association needed". 1125 o Added some text about how two STAs discover each other. 1127 o Added mention of external (OCB) and internal network (stable), in 1128 the subnet structure section. 1130 o Added phrase explaining that both .11 Data and .11 QoS Data 1131 headers are currently being used, and may be used in the future. 1133 o Moved the packet capture example into an Appendix Implementation 1134 Status. 1136 o Suggested moving the reliability requirements appendix out into 1137 another document. 1139 o Added a IANA Consiserations section, with content, requesting for 1140 a new multicast group "all OCB interfaces". 1142 o Added new OBU term, improved the RSU term definition, removed the 1143 ETTC term, replaced more occurences of 802.11p, 802.11-OCB with 1144 802.11-OCB. 1146 o References: 1148 * Added an informational reference to ETSI's IPv6-over- 1149 GeoNetworking. 1151 * Added more references to IETF and ETSI security protocols. 1153 * Updated some references from I-D to RFC, and from old RFC to 1154 new RFC numbers. 1156 * Added reference to multicast extensions to IPsec architecture 1157 RFC. 1159 * Added a reference to 2464-bis. 1161 * Removed FCC informative references, because not used. 1163 o Updated the affiliation of one author. 1165 o Reformulation of some phrases for better readability, and 1166 correction of typographical errors. 1168 From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave- 1169 ipv6-over-80211ocb-04 1171 o Removed a few informative references pointing to Dx draft IEEE 1172 1609 documents. 1174 o Removed outdated informative references to ETSI documents. 1176 o Added citations to IEEE 1609.2, .3 and .4-2016. 1178 o Minor textual issues. 1180 From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave- 1181 ipv6-over-80211ocb-03 1183 o Keep the previous text on multiple addresses, so remove talk about 1184 MIP6, NEMOv6 and MCoA. 1186 o Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon. 1188 o Clarified the figure showing Infrastructure mode and OCB mode side 1189 by side. 1191 o Added a reference to the IP Security Architecture RFC. 1193 o Detailed the IPv6-per-channel prohibition paragraph which reflects 1194 the discussion at the last IETF IPWAVE WG meeting. 1196 o Added section "Address Mapping -- Unicast". 1198 o Added the ".11 Trailer" to pictures of 802.11 frames. 1200 o Added text about SNAP carrying the Ethertype. 1202 o New RSU definition allowing for it be both a Router and not 1203 necessarily a Router some times. 1205 o Minor textual issues. 1207 From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave- 1208 ipv6-over-80211ocb-02 1210 o Replaced almost all occurences of 802.11p with 802.11-OCB, leaving 1211 only when explanation of evolution was necessary. 1213 o Shortened by removing parameter details from a paragraph in the 1214 Introduction. 1216 o Moved a reference from Normative to Informative. 1218 o Added text in intro clarifying there is no handover spec at IEEE, 1219 and that 1609.2 does provide security services. 1221 o Named the contents the fields of the EthernetII header (including 1222 the Ethertype bitstring). 1224 o Improved relationship between two paragraphs describing the 1225 increase of the Sequence Number in 802.11 header upon IP 1226 fragmentation. 1228 o Added brief clarification of "tracking". 1230 From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave- 1231 ipv6-over-80211ocb-01 1233 o Introduced message exchange diagram illustrating differences 1234 between 802.11 and 802.11 in OCB mode. 1236 o Introduced an appendix listing for information the set of 802.11 1237 messages that may be transmitted in OCB mode. 1239 o Removed appendix sections "Privacy Requirements", "Authentication 1240 Requirements" and "Security Certificate Generation". 1242 o Removed appendix section "Non IP Communications". 1244 o Introductory phrase in the Security Considerations section. 1246 o Improved the definition of "OCB". 1248 o Introduced theoretical stacked layers about IPv6 and IEEE layers 1249 including EPD. 1251 o Removed the appendix describing the details of prohibiting IPv6 on 1252 certain channels relevant to 802.11-OCB. 1254 o Added a brief reference in the privacy text about a precise clause 1255 in IEEE 1609.3 and .4. 1257 o Clarified the definition of a Road Side Unit. 1259 o Removed the discussion about security of WSA (because is non-IP). 1261 o Removed mentioning of the GeoNetworking discussion. 1263 o Moved references to scientific articles to a separate 'overview' 1264 draft, and referred to it. 1266 Appendix B. 802.11p 1268 The term "802.11p" is an earlier definition. The behaviour of 1269 "802.11p" networks is rolled in the document IEEE Std 802.11-2016. 1270 In that document the term 802.11p disappears. Instead, each 802.11p 1271 feature is conditioned by the IEEE Management Information Base (MIB) 1272 attribute "OCBActivated" [IEEE-802.11-2016]. Whenever OCBActivated 1273 is set to true the IEEE Std 802.11-OCB state is activated. For 1274 example, an 802.11 STAtion operating outside the context of a basic 1275 service set has the OCBActivated flag set. Such a station, when it 1276 has the flag set, uses a BSS identifier equal to ff:ff:ff:ff:ff:ff. 1278 Appendix C. Aspects introduced by the OCB mode to 802.11 1280 In the IEEE 802.11-OCB mode, all nodes in the wireless range can 1281 directly communicate with each other without involving authentication 1282 or association procedures. In OCB mode, the manner in which channels 1283 are selected and used is simplified compared to when in BSS mode. 1284 Contrary to BSS mode, at link layer, it is necessary to set 1285 statically the same channel number (or frequency) on two stations 1286 that need to communicate with each other (in BSS mode this channel 1287 set operation is performed automatically during 'scanning'). The 1288 manner in which stations set their channel number in OCB mode is not 1289 specified in this document. Stations STA1 and STA2 can exchange IP 1290 packets only if they are set on the same channel. At IP layer, they 1291 then discover each other by using the IPv6 Neighbor Discovery 1292 protocol. The allocation of a particular channel for a particular 1293 use is defined statically in standards authored by ETSI (in Europe), 1294 FCC in America, and similar organisations in South Korea, Japan and 1295 other parts of the world. 1297 Briefly, the IEEE 802.11-OCB mode has the following properties: 1299 o The use by each node of a 'wildcard' BSSID (i.e., each bit of the 1300 BSSID is set to 1) 1302 o No IEEE 802.11 Beacon frames are transmitted 1304 o No authentication is required in order to be able to communicate 1306 o No association is needed in order to be able to communicate 1308 o No encryption is provided in order to be able to communicate 1310 o Flag dot11OCBActivated is set to true 1312 All the nodes in the radio communication range (IP-OBU and IP-RSU) 1313 receive all the messages transmitted (IP-OBU and IP-RSU) within the 1314 radio communications range. The eventual conflict(s) are resolved by 1315 the MAC CDMA function. 1317 The message exchange diagram in Figure 3 illustrates a comparison 1318 between traditional 802.11 and 802.11 in OCB mode. The 'Data' 1319 messages can be IP packets such as HTTP or others. Other 802.11 1320 management and control frames (non IP) may be transmitted, as 1321 specified in the 802.11 standard. For information, the names of 1322 these messages as currently specified by the 802.11 standard are 1323 listed in Appendix G. 1325 STA AP STA1 STA2 1326 | | | | 1327 |<------ Beacon -------| |<------ Data -------->| 1328 | | | | 1329 |---- Probe Req. ----->| |<------ Data -------->| 1330 |<--- Probe Res. ------| | | 1331 | | |<------ Data -------->| 1332 |---- Auth Req. ------>| | | 1333 |<--- Auth Res. -------| |<------ Data -------->| 1334 | | | | 1335 |---- Asso Req. ------>| |<------ Data -------->| 1336 |<--- Asso Res. -------| | | 1337 | | |<------ Data -------->| 1338 |<------ Data -------->| | | 1339 |<------ Data -------->| |<------ Data -------->| 1341 (i) 802.11 Infrastructure mode (ii) 802.11-OCB mode 1343 Figure 3: Difference between messages exchanged on 802.11 (left) and 1344 802.11-OCB (right) 1346 The interface 802.11-OCB was specified in IEEE Std 802.11p (TM) -2010 1347 [IEEE-802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, 1348 titled "Amendment 6: Wireless Access in Vehicular Environments". 1349 Since then, this amendment has been integrated in IEEE 802.11(TM) 1350 -2012 and -2016 [IEEE-802.11-2016]. 1352 In document 802.11-2016, anything qualified specifically as 1353 "OCBActivated", or "outside the context of a basic service" set to be 1354 true, then it is actually referring to OCB aspects introduced to 1355 802.11. 1357 In order to delineate the aspects introduced by 802.11-OCB to 802.11, 1358 we refer to the earlier [IEEE-802.11p-2010]. The amendment is 1359 concerned with vehicular communications, where the wireless link is 1360 similar to that of Wireless LAN (using a PHY layer specified by 1361 802.11a/b/g/n), but which needs to cope with the high mobility factor 1362 inherent in scenarios of communications between moving vehicles, and 1363 between vehicles and fixed infrastructure deployed along roads. 1364 While 'p' is a letter identifying the Ammendment, just like 'a, b, g' 1365 and 'n' are, 'p' is concerned more with MAC modifications, and a 1366 little with PHY modifications; the others are mainly about PHY 1367 modifications. It is possible in practice to combine a 'p' MAC with 1368 an 'a' PHY by operating outside the context of a BSS with OFDM at 1369 5.4GHz and 5.9GHz. 1371 The 802.11-OCB links are specified to be compatible as much as 1372 possible with the behaviour of 802.11a/b/g/n and future generation 1373 IEEE WLAN links. From the IP perspective, an 802.11-OCB MAC layer 1374 offers practically the same interface to IP as the 802.11a/b/g/n and 1375 802.3. A packet sent by an IP-OBU may be received by one or multiple 1376 IP-RSUs. The link-layer resolution is performed by using the IPv6 1377 Neighbor Discovery protocol. 1379 To support this similarity statement (IPv6 is layered on top of LLC 1380 on top of 802.11-OCB, in the same way that IPv6 is layered on top of 1381 LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on 1382 top of 802.3 (for Ethernet)) it is useful to analyze the differences 1383 between 802.11-OCB and 802.11 specifications. During this analysis, 1384 we note that whereas 802.11-OCB lists relatively complex and numerous 1385 changes to the MAC layer (and very little to the PHY layer), there 1386 are only a few characteristics which may be important for an 1387 implementation transmitting IPv6 packets on 802.11-OCB links. 1389 The most important 802.11-OCB point which influences the IPv6 1390 functioning is the OCB characteristic; an additional, less direct 1391 influence, is the maximum bandwidth afforded by the PHY modulation/ 1392 demodulation methods and channel access specified by 802.11-OCB. The 1393 maximum bandwidth theoretically possible in 802.11-OCB is 54 Mbit/s 1394 (when using, for example, the following parameters: 20 MHz channel; 1395 modulation 64-QAM; coding rate R is 3/4); in practice of IP-over- 1396 802.11-OCB a commonly observed figure is 12Mbit/s; this bandwidth 1397 allows the operation of a wide range of protocols relying on IPv6. 1399 o Operation Outside the Context of a BSS (OCB): the (earlier 1400 802.11p) 802.11-OCB links are operated without a Basic Service Set 1401 (BSS). This means that the frames IEEE 802.11 Beacon, Association 1402 Request/Response, Authentication Request/Response, and similar, 1403 are not used. The used identifier of BSS (BSSID) has a 1404 hexadecimal value always 0xffffffffffff (48 '1' bits, represented 1405 as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' 1406 BSSID), as opposed to an arbitrary BSSID value set by 1407 administrator (e.g. 'My-Home-AccessPoint'). The OCB operation - 1408 namely the lack of beacon-based scanning and lack of 1409 authentication - should be taken into account when the Mobile IPv6 1410 protocol [RFC6275] and the protocols for IP layer security 1411 [RFC4301] are used. The way these protocols adapt to OCB is not 1412 described in this document. 1414 o Timing Advertisement: is a new message defined in 802.11-OCB, 1415 which does not exist in 802.11a/b/g/n. This message is used by 1416 stations to inform other stations about the value of time. It is 1417 similar to the time as delivered by a GNSS system (Galileo, GPS, 1418 ...) or by a cellular system. This message is optional for 1419 implementation. 1421 o Frequency range: this is a characteristic of the PHY layer, with 1422 almost no impact on the interface between MAC and IP. However, it 1423 is worth considering that the frequency range is regulated by a 1424 regional authority (ARCEP, ECC/CEPT based on ENs from ETSI, FCC, 1425 etc.); as part of the regulation process, specific applications 1426 are associated with specific frequency ranges. In the case of 1427 802.11-OCB, the regulator associates a set of frequency ranges, or 1428 slots within a band, to the use of applications of vehicular 1429 communications, in a band known as "5.9GHz". The 5.9GHz band is 1430 different from the 2.4GHz and 5GHz bands used by Wireless LAN. 1431 However, as with Wireless LAN, the operation of 802.11-OCB in 1432 "5.9GHz" bands is exempt from owning a license in EU (in US the 1433 5.9GHz is a licensed band of spectrum; for the fixed 1434 infrastructure an explicit FCC authorization is required; for an 1435 on-board device a 'licensed-by-rule' concept applies: rule 1436 certification conformity is required.) Technical conditions are 1437 different than those of the bands "2.4GHz" or "5GHz". The allowed 1438 power levels, and implicitly the maximum allowed distance between 1439 vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20 1440 dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum 1441 distance of approximately 1km, compared to approximately 50m. 1442 Additionally, specific conditions related to congestion avoidance, 1443 jamming avoidance, and radar detection are imposed on the use of 1444 DSRC (in US) and on the use of frequencies for Intelligent 1445 Transportation Systems (in EU), compared to Wireless LAN 1446 (802.11a/b/g/n). 1448 o 'Half-rate' encoding: as the frequency range, this parameter is 1449 related to PHY, and thus has not much impact on the interface 1450 between the IP layer and the MAC layer. 1452 o In vehicular communications using 802.11-OCB links, there are 1453 strong privacy requirements with respect to addressing. While the 1454 802.11-OCB standard does not specify anything in particular with 1455 respect to MAC addresses, in these settings there exists a strong 1456 need for dynamic change of these addresses (as opposed to the non- 1457 vehicular settings - real wall protection - where fixed MAC 1458 addresses do not currently pose some privacy risks). This is 1459 further described in Section 5. A relevant function is described 1460 in documents IEEE 1609.3-2016 [IEEE-1609.3] and IEEE 1609.4-2016 1461 [IEEE-1609.4]. 1463 Appendix D. Changes Needed on a software driver 802.11a to become a 1464 802.11-OCB driver 1466 The 802.11p amendment modifies both the 802.11 stack's physical and 1467 MAC layers but all the induced modifications can be quite easily 1468 obtained by modifying an existing 802.11a ad-hoc stack. 1470 Conditions for a 802.11a hardware to be 802.11-OCB compliant: 1472 o The PHY entity shall be an orthogonal frequency division 1473 multiplexing (OFDM) system. It must support the frequency bands 1474 on which the regulator recommends the use of ITS communications, 1475 for example using IEEE 802.11-OCB layer, in France: 5875MHz to 1476 5925MHz. 1478 o The OFDM system must provide a "half-clocked" operation using 10 1479 MHz channel spacings. 1481 o The chip transmit spectrum mask must be compliant to the "Transmit 1482 spectrum mask" from the IEEE 802.11p amendment (but experimental 1483 environments tolerate otherwise). 1485 o The chip should be able to transmit up to 44.8 dBm when used by 1486 the US government in the United States, and up to 33 dBm in 1487 Europe; other regional conditions apply. 1489 Changes needed on the network stack in OCB mode: 1491 o Physical layer: 1493 * The chip must use the Orthogonal Frequency Multiple Access 1494 (OFDM) encoding mode. 1496 * The chip must be set in half-mode rate mode (the internal clock 1497 frequency is divided by two). 1499 * The chip must use dedicated channels and should allow the use 1500 of higher emission powers. This may require modifications to 1501 the local computer file that describes regulatory domains 1502 rules, if used by the kernel to enforce local specific 1503 restrictions. Such modifications to the local computer file 1504 must respect the location-specific regulatory rules. 1506 MAC layer: 1508 * All management frames (beacons, join, leave, and others) 1509 emission and reception must be disabled except for frames of 1510 subtype Action and Timing Advertisement (defined below). 1512 * No encryption key or method must be used. 1514 * Packet emission and reception must be performed as in ad-hoc 1515 mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff). 1517 * The functions related to joining a BSS (Association Request/ 1518 Response) and for authentication (Authentication Request/Reply, 1519 Challenge) are not called. 1521 * The beacon interval is always set to 0 (zero). 1523 * Timing Advertisement frames, defined in the amendment, should 1524 be supported. The upper layer should be able to trigger such 1525 frames emission and to retrieve information contained in 1526 received Timing Advertisements. 1528 Appendix E. Protocol Layering 1530 A more theoretical and detailed view of layer stacking, and 1531 interfaces between the IP layer and 802.11-OCB layers, is illustrated 1532 in Figure 4. The IP layer operates on top of the EtherType Protocol 1533 Discrimination (EPD); this Discrimination layer is described in IEEE 1534 Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP 1535 (Link Layer Control Service Access Point). 1537 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1538 | IPv6 | 1539 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ 1540 { LLC_SAP } 802.11-OCB 1541 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary 1542 | EPD | | | 1543 | | MLME | | 1544 +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | 1545 | MAC Sublayer | | | 802.11-OCB 1546 | and ch. coord. | | SME | Services 1547 +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | 1548 | | PLME | | 1549 | PHY Layer | PLME_SAP | 1550 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1552 Figure 4: EtherType Protocol Discrimination 1554 Appendix F. Design Considerations 1556 The networks defined by 802.11-OCB are in many ways similar to other 1557 networks of the 802.11 family. In theory, the encapsulation of IPv6 1558 over 802.11-OCB could be very similar to the operation of IPv6 over 1559 other networks of the 802.11 family. However, the high mobility, 1560 strong link asymmetry and very short connection makes the 802.11-OCB 1561 link significantly different from other 802.11 networks. Also, the 1562 automotive applications have specific requirements for reliability, 1563 security and privacy, which further add to the particularity of the 1564 802.11-OCB link. 1566 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode 1568 For information, at the time of writing, this is the list of IEEE 1569 802.11 messages that may be transmitted in OCB mode, i.e. when 1570 dot11OCBActivated is true in a STA: 1572 o The STA may send management frames of subtype Action and, if the 1573 STA maintains a TSF Timer, subtype Timing Advertisement; 1575 o The STA may send control frames, except those of subtype PS-Poll, 1576 CF-End, and CF-End plus CFAck; 1578 o The STA may send data frames of subtype Data, Null, QoS Data, and 1579 QoS Null. 1581 Appendix H. Examples of Packet Formats 1583 This section describes an example of an IPv6 Packet captured over a 1584 IEEE 802.11-OCB link. 1586 By way of example we show that there is no modification in the 1587 headers when transmitted over 802.11-OCB networks - they are 1588 transmitted like any other 802.11 and Ethernet packets. 1590 We describe an experiment of capturing an IPv6 packet on an 1591 802.11-OCB link. In topology depicted in Figure 5, the packet is an 1592 IPv6 Router Advertisement. This packet is emitted by a Router on its 1593 802.11-OCB interface. The packet is captured on the Host, using a 1594 network protocol analyzer (e.g. Wireshark); the capture is performed 1595 in two different modes: direct mode and 'monitor' mode. The topology 1596 used during the capture is depicted below. 1598 The packet is captured on the Host. The Host is an IP-OBU containing 1599 an 802.11 interface in format PCI express (an ITRI product). The 1600 kernel runs the ath5k software driver with modifications for OCB 1601 mode. The capture tool is Wireshark. The file format for save and 1602 analyze is 'pcap'. The packet is generated by the Router. The 1603 Router is an IP-RSU (ITRI product). 1605 +--------+ +-------+ 1606 | | 802.11-OCB Link | | 1607 ---| Router |--------------------------------| Host | 1608 | | | | 1609 +--------+ +-------+ 1611 Figure 5: Topology for capturing IP packets on 802.11-OCB 1613 During several capture operations running from a few moments to 1614 several hours, no message relevant to the BSSID contexts were 1615 captured (no Association Request/Response, Authentication Req/Resp, 1616 Beacon). This shows that the operation of 802.11-OCB is outside the 1617 context of a BSSID. 1619 Overall, the captured message is identical with a capture of an IPv6 1620 packet emitted on a 802.11b interface. The contents are precisely 1621 similar. 1623 H.1. Capture in Monitor Mode 1625 The IPv6 RA packet captured in monitor mode is illustrated below. 1626 The radio tap header provides more flexibility for reporting the 1627 characteristics of frames. The Radiotap Header is prepended by this 1628 particular stack and operating system on the Host machine to the RA 1629 packet received from the network (the Radiotap Header is not present 1630 on the air). The implementation-dependent Radiotap Header is useful 1631 for piggybacking PHY information from the chip's registers as data in 1632 a packet understandable by userland applications using Socket 1633 interfaces (the PHY interface can be, for example: power levels, data 1634 rate, ratio of signal to noise). 1636 The packet present on the air is formed by IEEE 802.11 Data Header, 1637 Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. 1639 Radiotap Header v0 1640 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1641 |Header Revision| Header Pad | Header length | 1642 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1643 | Present flags | 1644 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1645 | Data Rate | Pad | 1646 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1648 IEEE 802.11 Data Header 1649 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1650 | Type/Subtype and Frame Ctrl | Duration | 1651 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1652 | Receiver Address... 1653 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1654 ... Receiver Address | Transmitter Address... 1655 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1656 ... Transmitter Address | 1657 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1658 | BSS Id... 1659 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1660 ... BSS Id | Frag Number and Seq Number | 1661 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1663 Logical-Link Control Header 1664 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1665 | DSAP |I| SSAP |C| Control field | Org. code... 1666 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1667 ... Organizational Code | Type | 1668 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1670 IPv6 Base Header 1671 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1672 |Version| Traffic Class | Flow Label | 1673 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1674 | Payload Length | Next Header | Hop Limit | 1675 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1676 | | 1677 + + 1678 | | 1679 + Source Address + 1680 | | 1681 + + 1682 | | 1683 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1684 | | 1685 + + 1686 | | 1687 + Destination Address + 1688 | | 1689 + + 1690 | | 1691 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1693 Router Advertisement 1694 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1695 | Type | Code | Checksum | 1696 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1697 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1698 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1699 | Reachable Time | 1700 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1701 | Retrans Timer | 1702 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1703 | Options ... 1704 +-+-+-+-+-+-+-+-+-+-+-+- 1706 The value of the Data Rate field in the Radiotap header is set to 6 1707 Mb/s. This indicates the rate at which this RA was received. 1709 The value of the Transmitter address in the IEEE 802.11 Data Header 1710 is set to a 48bit value. The value of the destination address is 1711 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS 1712 Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network 1713 protocol analyzer as being "broadcast". The Fragment number and 1714 sequence number fields are together set to 0x90C6. 1716 The value of the Organization Code field in the Logical-Link Control 1717 Header is set to 0x0, recognized as "Encapsulated Ethernet". The 1718 value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise 1719 #86DD), recognized as "IPv6". 1721 A Router Advertisement is periodically sent by the router to 1722 multicast group address ff02::1. It is an icmp packet type 134. The 1723 IPv6 Neighbor Discovery's Router Advertisement message contains an 1724 8-bit field reserved for single-bit flags, as described in [RFC4861]. 1726 The IPv6 header contains the link local address of the router 1727 (source) configured via EUI-64 algorithm, and destination address set 1728 to ff02::1. 1730 The Ethernet Type field in the logical-link control header is set to 1731 0x86dd which indicates that the frame transports an IPv6 packet. In 1732 the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 1733 which is the corresponding multicast MAC address. The BSS id is a 1734 broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link 1735 duration between vehicles and the roadside infrastructure, there is 1736 no need in IEEE 802.11-OCB to wait for the completion of association 1737 and authentication procedures before exchanging data. IEEE 1738 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) 1739 and may start communicating as soon as they arrive on the 1740 communication channel. 1742 H.2. Capture in Normal Mode 1744 The same IPv6 Router Advertisement packet described above (monitor 1745 mode) is captured on the Host, in the Normal mode, and depicted 1746 below. 1748 Ethernet II Header 1749 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1750 | Destination... 1751 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1752 ...Destination | Source... 1753 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1754 ...Source | 1755 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1756 | Type | 1757 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1759 IPv6 Base Header 1760 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1761 |Version| Traffic Class | Flow Label | 1762 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1763 | Payload Length | Next Header | Hop Limit | 1764 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1765 | | 1766 + + 1767 | | 1768 + Source Address + 1769 | | 1770 + + 1771 | | 1772 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1773 | | 1774 + + 1775 | | 1776 + Destination Address + 1777 | | 1778 + + 1779 | | 1780 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1782 Router Advertisement 1783 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1784 | Type | Code | Checksum | 1785 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1786 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1787 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1788 | Reachable Time | 1789 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1790 | Retrans Timer | 1791 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1792 | Options ... 1793 +-+-+-+-+-+-+-+-+-+-+-+- 1795 One notices that the Radiotap Header, the IEEE 802.11 Data Header and 1796 the Logical-Link Control Headers are not present. On the other hand, 1797 a new header named Ethernet II Header is present. 1799 The Destination and Source addresses in the Ethernet II header 1800 contain the same values as the fields Receiver Address and 1801 Transmitter Address present in the IEEE 802.11 Data Header in the 1802 "monitor" mode capture. 1804 The value of the Type field in the Ethernet II header is 0x86DD 1805 (recognized as "IPv6"); this value is the same value as the value of 1806 the field Type in the Logical-Link Control Header in the "monitor" 1807 mode capture. 1809 The knowledgeable experimenter will no doubt notice the similarity of 1810 this Ethernet II Header with a capture in normal mode on a pure 1811 Ethernet cable interface. 1813 An Adaptation layer is inserted on top of a pure IEEE 802.11 MAC 1814 layer, in order to adapt packets, before delivering the payload data 1815 to the applications. It adapts 802.11 LLC/MAC headers to Ethernet II 1816 headers. In further detail, this adaptation consists in the 1817 elimination of the Radiotap, 802.11 and LLC headers, and in the 1818 insertion of the Ethernet II header. In this way, IPv6 runs straight 1819 over LLC over the 802.11-OCB MAC layer; this is further confirmed by 1820 the use of the unique Type 0x86DD. 1822 Appendix I. Extra Terminology 1824 The following terms are defined outside the IETF. They are used to 1825 define the main terms in the main terminology section Section 2. 1827 DSRC (Dedicated Short Range Communication): a term defined outside 1828 the IETF. The US Federal Communications Commission (FCC) Dedicated 1829 Short Range Communication (DSRC) is defined in the Code of Federal 1830 Regulations (CFR) 47, Parts 90 and 95. This Code is referred in the 1831 definitions below. At the time of the writing of this Internet 1832 Draft, the last update of this Code was dated October 1st, 2010. 1834 DSRCS (Dedicated Short-Range Communications Services): a term defined 1835 outside the IETF. The use of radio techniques to transfer data over 1836 short distances between roadside and mobile units, between mobile 1837 units, and between portable and mobile units to perform operations 1838 related to the improvement of traffic flow, traffic safety, and other 1839 intelligent transportation service applications in a variety of 1840 environments. DSRCS systems may also transmit status and 1841 instructional messages related to the units involve. [Ref. 47 CFR 1842 90.7 - Definitions] 1843 OBU (On-Board Unit): a term defined outside the IETF. An On-Board 1844 Unit is a DSRCS transceiver that is normally mounted in or on a 1845 vehicle, or which in some instances may be a portable unit. An OBU 1846 can be operational while a vehicle or person is either mobile or 1847 stationary. The OBUs receive and contend for time to transmit on one 1848 or more radio frequency (RF) channels. Except where specifically 1849 excluded, OBU operation is permitted wherever vehicle operation or 1850 human passage is permitted. The OBUs mounted in vehicles are 1851 licensed by rule under part 95 of the respective chapter and 1852 communicate with Roadside Units (RSUs) and other OBUs. Portable OBUs 1853 are also licensed by rule under part 95 of the respective chapter. 1854 OBU operations in the Unlicensed National Information Infrastructure 1855 (UNII) Bands follow the rules in those bands. - [CFR 90.7 - 1856 Definitions]. 1858 RSU (Road-Side Unit): a term defined outside of IETF. A Roadside 1859 Unit is a DSRC transceiver that is mounted along a road or pedestrian 1860 passageway. An RSU may also be mounted on a vehicle or is hand 1861 carried, but it may only operate when the vehicle or hand- carried 1862 unit is stationary. Furthermore, an RSU operating under the 1863 respectgive part is restricted to the location where it is licensed 1864 to operate. However, portable or hand-held RSUs are permitted to 1865 operate where they do not interfere with a site-licensed operation. 1866 A RSU broadcasts data to OBUs or exchanges data with OBUs in its 1867 communications zone. An RSU also provides channel assignments and 1868 operating instructions to OBUs in its communications zone, when 1869 required. - [CFR 90.7 - Definitions]. 1871 Appendix J. Neighbor Discovery (ND) Potential Issues in Wireless Links 1873 IPv6 Neighbor Discovery (IPv6 ND) [RFC4861][RFC4862] was designed for 1874 point-to-point and transit links such as Ethernet, with the 1875 expectation of a cheap and reliable support for multicast from the 1876 lower layer. Section 3.2 of RFC 4861 indicates that the operation on 1877 Shared Media and on non-broadcast multi-access (NBMA) networks 1878 require additional support, e.g., for Address Resolution (AR) and 1879 duplicate address detection (DAD), which depend on multicast. An 1880 infrastructureless radio network such as OCB shares properties with 1881 both Shared Media and NBMA networks, and then adds its own 1882 complexity, e.g., from movement and interference that allow only 1883 transient and non-transitive reachability between any set of peers. 1885 The uniqueness of an address within a scoped domain is a key pillar 1886 of IPv6 and the base for unicast IP communication. RFC 4861 details 1887 the DAD method to avoid that an address is duplicated. For a link 1888 local address, the scope is the link, whereas for a global address 1889 the scope is much larger. The underlying assumption for DAD to 1890 operate correctly is that the node that owns an IPv6 address can 1891 reach any other node within the scope at the time it claims its 1892 address, which is done by sending a NS multicast message, and can 1893 hear any future claim for that address by another party within the 1894 scope for the duration of the address ownership. 1896 In the case of OCB, there is a potentially a need to define a scope 1897 that is compatible with DAD, and that cannot be the set of nodes that 1898 a transmitter can reach at a particular time, because that set varies 1899 all the time and does not meet the DAD requirements for a link local 1900 address that could possibly be used anytime, anywhere. The generic 1901 expectation of a reliable multicast is not ensured, and the operation 1902 of DAD and AR (Address Resolution) as specificed by RFC 4861 cannot 1903 be guaranteed. Moreoever, multicast transmissions that rely on 1904 broadcast are not only unreliable but are also often detrimental to 1905 unicast traffic (see [draft-ietf-mboned-ieee802-mcast-problems]). 1907 Early experiences indicate that it should be possible to exchange 1908 IPv6 packets over OCB while relying on IPv6 ND alone for DAD and AR 1909 (Address Resolution). In the absence of a correct DAD operation, a 1910 node that relies only on IPv6 ND for AR and DAD over OCB should 1911 ensure that the addresses that it uses are unique by means others 1912 than DAD. It must be noted that deriving an IPv6 address from a 1913 globally unique MAC address has this property but may yield privacy 1914 issues. 1916 RFC 8505 provides a more recent approach to IPv6 ND and in particular 1917 DAD. RFC 8505 is designed to fit wireless and otherwise constrained 1918 networks whereby multicast and/or continuous access to the medium may 1919 not be guaranteed. RFC 8505 Section 5.6 "Link-Local Addresses and 1920 Registration" indicates that the scope of uniqueness for a link local 1921 address is restricted to a pair of nodes that use it to communicate, 1922 and provides a method to assert the uniqueness and resolve the link- 1923 Layer address using a unicast exchange. 1925 RFC 8505 also enables a router (acting as a 6LR) to own a prefix and 1926 act as a registrar (acting as a 6LBR) for addresses within the 1927 associated subnet. A peer host (acting as a 6LN) registers an 1928 address derived from that prefix and can use it for the lifetime of 1929 the registration. The prefix is advertised as not onlink, which 1930 means that the 6LN uses the 6LR to relay its packets within the 1931 subnet, and participation to the subnet is constrained to the time of 1932 reachability to the 6LR. Note that RSU that provides internet 1933 connectivity MAY announce a default router preference [RFC 4191], 1934 whereas a car that does not provide that connectivity MUST NOT do so. 1935 This operation presents similarities with that of an access point, 1936 but at Layer-3. This is why RFC 8505 well-suited for wireless in 1937 general. 1939 Support of RFC 8505 is may be implemented on OCB. OCB nodes that 1940 support RFC 8505 would support the 6LN operation in order to act as a 1941 host, and may support the 6LR and 6LBR operations in order to act as 1942 a router and in particular own a prefix that can be used by RFC 1943 8505-compliant hosts for address autoconfiguration and registration. 1945 Authors' Addresses 1947 Alexandre Petrescu 1948 CEA, LIST 1949 CEA Saclay 1950 Gif-sur-Yvette , Ile-de-France 91190 1951 France 1953 Phone: +33169089223 1954 Email: Alexandre.Petrescu@cea.fr 1956 Nabil Benamar 1957 Moulay Ismail University 1958 Morocco 1960 Phone: +212670832236 1961 Email: n.benamar@est.umi.ac.ma 1963 Jerome Haerri 1964 Eurecom 1965 Sophia-Antipolis 06904 1966 France 1968 Phone: +33493008134 1969 Email: Jerome.Haerri@eurecom.fr 1971 Jong-Hyouk Lee 1972 Sangmyung University 1973 31, Sangmyeongdae-gil, Dongnam-gu 1974 Cheonan 31066 1975 Republic of Korea 1977 Email: jonghyouk@smu.ac.kr 1978 Thierry Ernst 1979 YoGoKo 1980 France 1982 Email: thierry.ernst@yogoko.fr