idnits 2.17.1 draft-ietf-ipwave-ipv6-over-80211ocb-44.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 23, 2019) is 1829 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 1891, but not defined == Missing Reference: 'RFC 4191' is mentioned on line 1952, 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reference: RFC 7042 (Obsoleted by RFC 9542) ** Downref: Normative reference to an Informational RFC: RFC 7721 == Outdated reference: A later version (-30) exists of draft-ietf-ipwave-vehicular-networking-08 == Outdated reference: A later version (-15) exists of draft-ietf-mboned-ieee802-mcast-problems-05 Summary: 5 errors (**), 0 flaws (~~), 6 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IPWAVE Working Group N. Benamar 3 Internet-Draft Moulay Ismail University 4 Intended status: Standards Track J. Haerri 5 Expires: October 25, 2019 Eurecom 6 J. Lee 7 Sangmyung University 8 T. Ernst 9 YoGoKo 10 April 23, 2019 12 Transmission of IPv6 Packets over IEEE 802.11 Networks operating in mode 13 Outside the Context of a Basic Service Set (IPv6-over-80211-OCB) 14 draft-ietf-ipwave-ipv6-over-80211ocb-44 16 Abstract 18 In order to transmit IPv6 packets on IEEE 802.11 networks running 19 outside the context of a basic service set (OCB, earlier "802.11p") 20 there is a need to define a few parameters such as the supported 21 Maximum Transmission Unit size on the 802.11-OCB link, the header 22 format preceding the IPv6 header, the Type value within it, and 23 others. This document describes these parameters for IPv6 and IEEE 24 802.11-OCB networks; it portrays the layering of IPv6 on 802.11-OCB 25 similarly to other known 802.11 and Ethernet layers - by using an 26 Ethernet Adaptation Layer. 28 Status of This Memo 30 This Internet-Draft is submitted in full conformance with the 31 provisions of BCP 78 and BCP 79. 33 Internet-Drafts are working documents of the Internet Engineering 34 Task Force (IETF). Note that other groups may also distribute 35 working documents as Internet-Drafts. The list of current Internet- 36 Drafts is at https://datatracker.ietf.org/drafts/current/. 38 Internet-Drafts are draft documents valid for a maximum of six months 39 and may be updated, replaced, or obsoleted by other documents at any 40 time. It is inappropriate to use Internet-Drafts as reference 41 material or to cite them other than as "work in progress." 43 This Internet-Draft will expire on October 25, 2019. 45 Copyright Notice 47 Copyright (c) 2019 IETF Trust and the persons identified as the 48 document authors. All rights reserved. 50 This document is subject to BCP 78 and the IETF Trust's Legal 51 Provisions Relating to IETF Documents 52 (https://trustee.ietf.org/license-info) in effect on the date of 53 publication of this document. Please review these documents 54 carefully, as they describe your rights and restrictions with respect 55 to this document. Code Components extracted from this document must 56 include Simplified BSD License text as described in Section 4.e of 57 the Trust Legal Provisions and are provided without warranty as 58 described in the Simplified BSD License. 60 Table of Contents 62 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 63 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 64 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 4 65 4. IPv6 over 802.11-OCB . . . . . . . . . . . . . . . . . . . . 4 66 4.1. Maximum Transmission Unit (MTU) . . . . . . . . . . . . . 4 67 4.2. Frame Format . . . . . . . . . . . . . . . . . . . . . . 5 68 4.2.1. Ethernet Adaptation Layer . . . . . . . . . . . . . . 5 69 4.3. Link-Local Addresses . . . . . . . . . . . . . . . . . . 7 70 4.4. Stateless Autoconfiguration . . . . . . . . . . . . . . . 7 71 4.5. Address Mapping . . . . . . . . . . . . . . . . . . . . . 8 72 4.5.1. Address Mapping -- Unicast . . . . . . . . . . . . . 8 73 4.5.2. Address Mapping -- Multicast . . . . . . . . . . . . 8 74 4.6. Subnet Structure . . . . . . . . . . . . . . . . . . . . 8 75 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9 76 5.1. Privacy Considerations . . . . . . . . . . . . . . . . . 10 77 5.1.1. Privacy Risks of Meaningful info in Interface IDs . . 10 78 5.2. MAC Address and Interface ID Generation . . . . . . . . . 11 79 5.3. Pseudonym Handling . . . . . . . . . . . . . . . . . . . 11 80 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 81 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 12 82 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 83 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 84 9.1. Normative References . . . . . . . . . . . . . . . . . . 13 85 9.2. Informative References . . . . . . . . . . . . . . . . . 16 86 Appendix A. ChangeLog . . . . . . . . . . . . . . . . . . . . . 17 87 Appendix B. 802.11p . . . . . . . . . . . . . . . . . . . . . . 28 88 Appendix C. Aspects introduced by the OCB mode to 802.11 . . . . 28 89 Appendix D. Changes Needed on a software driver 802.11a to 90 become a 802.11-OCB driver . . . 32 91 Appendix E. Protocol Layering . . . . . . . . . . . . . . . . . 33 92 Appendix F. Design Considerations . . . . . . . . . . . . . . . 34 93 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode . . . . 34 94 Appendix H. Examples of Packet Formats . . . . . . . . . . . . . 35 95 H.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . 36 96 H.2. Capture in Normal Mode . . . . . . . . . . . . . . . . . 38 97 Appendix I. Extra Terminology . . . . . . . . . . . . . . . . . 40 98 Appendix J. Neighbor Discovery (ND) Potential Issues in Wireless 99 Links . . . . . . . . . . . . . . . . . . . . . . . 41 100 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 43 102 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] . 123 o Exceptions due to the OCB nature of 802.11-OCB compared to 802.11. 124 This has impacts on security, privacy, subnet structure and 125 movement detection. For security and privacy recommendations see 126 Section 5 and Section 4.4. The subnet structure is described in 127 Section 4.6. The movement detection on OCB links is not described 128 in this document. 130 In the published literature, many documents describe aspects and 131 problems related to running IPv6 over 802.11-OCB: 132 [I-D.ietf-ipwave-vehicular-networking]. 134 2. Terminology 136 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 137 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 138 "OPTIONAL" in this document are to be interpreted as described in BCP 139 14 [RFC2119] [RFC8174] when, and only when, they appear in all 140 capitals, as shown here. 142 IP-OBU (Internet Protocol On-Board Unit): an IP-OBU is a computer 143 situated in a vehicle such as an automobile, bicycle, or similar. It 144 has at least one IP interface that runs in mode OCB of 802.11, and 145 that has an "OBU" transceiver. See the definition of the term "OBU" 146 in section Appendix I. 148 IP-RSU (IP Road-Side Unit): an IP-RSU is situated along the road. It 149 has at least two distinct IP-enabled interfaces; the wireless PHY/MAC 150 layer of at least one of its IP-enabled interfaces is configured to 151 operate in 802.11-OCB mode. An IP-RSU communicates with the IP-OBU 152 in the vehicle over 802.11 wireless link operating in OCB mode. An 153 IP-RSU is similar to an Access Network Router (ANR) defined in 154 [RFC3753], and a Wireless Termination Point (WTP) defined in 155 [RFC5415]. 157 OCB (outside the context of a basic service set - BSS): A mode of 158 operation in which a STA is not a member of a BSS and does not 159 utilize IEEE Std 802.11 authentication, association, or data 160 confidentiality. 162 802.11-OCB: mode specified in IEEE Std 802.11-2016 when the MIB 163 attribute dot11OCBActivited is true. Note: compliance with standards 164 and regulations set in different countries when using the 5.9GHz 165 frequency band is required. 167 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 169 The IEEE 802.11-OCB Networks are used for vehicular communications, 170 as 'Wireless Access in Vehicular Environments'. The IP communication 171 scenarios for these environments have been described in several 172 documents; in particular, we refer the reader to 173 [I-D.ietf-ipwave-vehicular-networking], that lists some scenarios and 174 requirements for IP in Intelligent Transportation Systems. 176 The link model is the following: STA --- 802.11-OCB --- STA. In 177 vehicular networks, STAs can be IP-RSUs and/or IP-OBUs. While 178 802.11-OCB is clearly specified, and the use of IPv6 over such link 179 is not radically new, the operating environment (vehicular networks) 180 brings in new perspectives. 182 4. IPv6 over 802.11-OCB 184 4.1. Maximum Transmission Unit (MTU) 186 The default MTU for IP packets on 802.11-OCB MUST be 1500 octets. It 187 is the same value as IPv6 packets on Ethernet links, as specified in 188 [RFC2464]. This value of the MTU respects the recommendation that 189 every link on the Internet must have a minimum MTU of 1280 octets 190 (stated in [RFC8200], and the recommendations therein, especially 191 with respect to fragmentation). 193 4.2. Frame Format 195 IP packets MUST be transmitted over 802.11-OCB media as QoS Data 196 frames whose format is specified in IEEE 802.11(TM) -2016 197 [IEEE-802.11-2016]. 199 The IPv6 packet transmitted on 802.11-OCB MUST be immediately 200 preceded by a Logical Link Control (LLC) header and an 802.11 header. 201 In the LLC header, and in accordance with the EtherType Protocol 202 Discrimination (EPD, see Appendix E), the value of the Type field 203 MUST be set to 0x86DD (IPv6). In the 802.11 header, the value of the 204 Subtype sub-field in the Frame Control field MUST be set to 8 (i.e. 205 'QoS Data'); the value of the Traffic Identifier (TID) sub-field of 206 the QoS Control field of the 802.11 header MUST be set to binary 001 207 (i.e. User Priority 'Background', QoS Access Category 'AC_BK'). 209 To simplify the Application Programming Interface (API) between the 210 operating system and the 802.11-OCB media, device drivers MAY 211 implement an Ethernet Adaptation Layer that translates Ethernet II 212 frames to the 802.11 format and vice versa. An Ethernet Adaptation 213 Layer is described in Section 4.2.1. 215 4.2.1. Ethernet Adaptation Layer 217 An 'adaptation' layer is inserted between a MAC layer and the 218 Networking layer. This is used to transform some parameters between 219 their form expected by the IP stack and the form provided by the MAC 220 layer. 222 An Ethernet Adaptation Layer makes an 802.11 MAC look to IP 223 Networking layer as a more traditional Ethernet layer. At reception, 224 this layer takes as input the IEEE 802.11 header and the Logical-Link 225 Layer Control Header and produces an Ethernet II Header. At sending, 226 the reverse operation is performed. 228 The operation of the Ethernet Adaptation Layer is depicted by the 229 double arrow in Figure 1. 231 +------------------+------------+-------------+---------+-----------+ 232 | 802.11 header | LLC Header | IPv6 Header | Payload |.11 Trailer| 233 +------------------+------------+-------------+---------+-----------+ 234 \ / \ / 235 --------------------------- -------- 236 \---------------------------------------------/ 237 ^ 238 | 239 802.11-to-Ethernet Adaptation Layer 240 | 241 v 242 +---------------------+-------------+---------+ 243 | Ethernet II Header | IPv6 Header | Payload | 244 +---------------------+-------------+---------+ 246 Figure 1: Operation of the Ethernet Adaptation Layer 248 The Receiver and Transmitter Address fields in the 802.11 header MUST 249 contain the same values as the Destination and the Source Address 250 fields in the Ethernet II Header, respectively. The value of the 251 Type field in the LLC Header MUST be the same as the value of the 252 Type field in the Ethernet II Header. That value MUST be set to 253 0x86DD (IPv6). 255 The ".11 Trailer" contains solely a 4-byte Frame Check Sequence. 257 The placement of IPv6 networking layer on Ethernet Adaptation Layer 258 is illustrated in Figure 2. 260 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 261 | IPv6 | 262 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 263 | Ethernet Adaptation Layer | 264 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 265 | 802.11 MAC | 266 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 267 | 802.11 PHY | 268 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 270 Figure 2: Ethernet Adaptation Layer stacked with other layers 272 (in the above figure, a 802.11 profile is represented; this is used 273 also for 802.11-OCB profile.) 275 4.3. Link-Local Addresses 277 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 278 MAY be assigned to an 802.11-OCB interface. Among these types of 279 addresses only the IPv6 link-local addresses MAY be formed using an 280 EUI-64 identifier, in particular during transition time. 282 If the IPv6 link-local address is formed using an EUI-64 identifier, 283 then the mechanism of forming that address is the same mechanism as 284 used to form an IPv6 link-local address on Ethernet links. This 285 mechanism is described in section 5 of [RFC2464]. 287 4.4. Stateless Autoconfiguration 289 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 290 MAY be assigned to an 802.11-OCB interface. This section describes 291 the formation of Interface Identifiers for IPv6 addresses of type 292 'Global' or 'Unique Local'. For Interface Identifiers for IPv6 293 address of type 'Link-Local' see Section 4.3. 295 The Interface Identifier for an 802.11-OCB interface is formed using 296 the same rules as the Interface Identifier for an Ethernet interface; 297 the RECOMMENDED method for forming stable Interface Identifiers 298 (IIDs) is described in [RFC8064]. The method of forming IIDs 299 described in section 4 of [RFC2464] MAY be used during transition 300 time, in particular for IPv6 link-local addresses. 302 The bits in the Interface Identifier have no generic meaning and the 303 identifier should be treated as an opaque value. The bits 304 'Universal' and 'Group' in the identifier of an 802.11-OCB interface 305 are significant, as this is an IEEE link-layer address. The details 306 of this significance are described in [RFC7136]. 308 Semantically opaque Interface Identifiers, instead of meaningful 309 Interface Identifiers derived from a valid and meaningful MAC address 310 ([RFC2464], section 4), help avoid certain privacy risks (see the 311 risks mentioned in Section 5.1.1). If semantically opaque Interface 312 Identifiers are needed, they MAY be generated using the method for 313 generating semantically opaque Interface Identifiers with IPv6 314 Stateless Address Autoconfiguration given in [RFC7217]. Typically, 315 an opaque Interface Identifier is formed starting from identifiers 316 different than the MAC addresses, and from cryptographically strong 317 material. Thus, privacy sensitive information is absent from 318 Interface IDs, because it is impossible to calculate back the initial 319 value from which the Interface ID was first generated (intuitively, 320 it is as hard as mentally finding the square root of a number, and as 321 impossible as trying to use computers to identify quickly whether a 322 large number is prime). 324 Some applications that use IPv6 packets on 802.11-OCB links (among 325 other link types) may benefit from IPv6 addresses whose Interface 326 Identifiers don't change too often. It is RECOMMENDED to use the 327 mechanisms described in RFC 7217 to permit the use of Stable 328 Interface Identifiers that do not change within one subnet prefix. A 329 possible source for the Net-Iface Parameter is a virtual interface 330 name, or logical interface name, that is decided by a local 331 administrator. 333 4.5. Address Mapping 335 Unicast and multicast address mapping MUST follow the procedures 336 specified for Ethernet interfaces in sections 6 and 7 of [RFC2464]. 338 4.5.1. Address Mapping -- Unicast 340 The procedure for mapping IPv6 unicast addresses into Ethernet link- 341 layer addresses is described in [RFC4861]. 343 4.5.2. Address Mapping -- Multicast 345 The multicast address mapping is performed according to the method 346 specified in section 7 of [RFC2464]. The meaning of the value "3333" 347 mentioned in that section 7 of [RFC2464] is defined in section 2.3.1 348 of [RFC7042]. 350 Transmitting IPv6 packets to multicast destinations over 802.11 links 351 proved to have some performance issues 352 [I-D.ietf-mboned-ieee802-mcast-problems]. These issues may be 353 exacerbated in OCB mode. Solutions for these problems SHOULD 354 consider the OCB mode of operation. 356 4.6. Subnet Structure 358 A subnet is formed by the external 802.11-OCB interfaces of vehicles 359 that are in close range (not by their in-vehicle interfaces). A 360 Prefix List conceptual data structure ([RFC4861] section 5.1) is 361 maintained for each 802.11-OCB interface. 363 The subnet structure on which the Neighbor Discovery protocol (ND) on 364 OCB works ok is a single-link subnet; the status of ND operation on a 365 subnet that covers multiple OCB links that repeat the signal at PHY 366 layer, or the messages at MAC layer, is unknown. 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. An Interface ID 499 SHOULD be of length specified in other documents. 501 5.3. Pseudonym Handling 503 The demand for privacy protection of vehicles' and drivers' 504 identities, which could be granted by using a pseudonym or alias 505 identity at the same time, may hamper the required confidentiality of 506 messages and trust between participants - especially in safety 507 critical vehicular communication. 509 o Particular challenges arise when the pseudonymization mechanism 510 used relies on (randomized) re-addressing. 512 o A proper pseudonymization tool operated by a trusted third party 513 may be needed to ensure both aspects simultaneously (privacy 514 protection on one hand and trust between participants on another 515 hand). 517 o This is discussed in Section 4.4 and Section 5 of this document. 519 o Pseudonymity is also discussed in 520 [I-D.ietf-ipwave-vehicular-networking] in its sections 4.2.4 and 521 5.1.2. 523 6. IANA Considerations 525 No request to IANA. 527 7. Contributors 529 Christian Huitema, Tony Li. 531 Romain Kuntz contributed extensively about IPv6 handovers between 532 links running outside the context of a BSS (802.11-OCB links). 534 Tim Leinmueller contributed the idea of the use of IPv6 over 535 802.11-OCB for distribution of certificates. 537 Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey 538 Voronov provided significant feedback on the experience of using IP 539 messages over 802.11-OCB in initial trials. 541 Michelle Wetterwald contributed extensively the MTU discussion, 542 offered the ETSI ITS perspective, and reviewed other parts of the 543 document. 545 8. Acknowledgements 547 The authors would like to thank Alexandre Petrescu for initiating 548 this work and for being the lead author until the version 43 of this 549 draft. 551 The authors would like to thank Witold Klaudel, Ryuji Wakikawa, 552 Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan 553 Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray 554 Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, 555 Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne, 556 Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark, 557 Bob Moskowitz, Andrew Dryden, Georg Mayer, Dorothy Stanley, Sandra 558 Cespedes, Mariano Falcitelli, Sri Gundavelli, Abdussalam Baryun, 559 Margaret Cullen, Erik Kline, Carlos Jesus Bernardos Cano, Ronald in 560 't Velt, Katrin Sjoberg, Roland Bless, Tijink Jasja, Kevin Smith, 561 Brian Carpenter, Julian Reschke, Mikael Abrahamsson, Dirk von Hugo, 562 Lorenzo Colitti, Pascal Thubert, Ole Troan, Jinmei Tatuya, Joel 563 Halpern, Eric Gray and William Whyte. Their valuable comments 564 clarified particular issues and generally helped to improve the 565 document. 567 Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB 568 drivers for linux and described how. 570 For the multicast discussion, the authors would like to thank Owen 571 DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and 572 participants to discussions in network working groups. 574 The authors would like to thank participants to the Birds-of- 575 a-Feather "Intelligent Transportation Systems" meetings held at IETF 576 in 2016. 578 Human Rights Protocol Considerations review by Amelia Andersdotter. 580 9. References 582 9.1. Normative References 584 [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission 585 of IP datagrams over IEEE 802 networks", STD 43, RFC 1042, 586 DOI 10.17487/RFC1042, February 1988, 587 . 589 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 590 Requirement Levels", BCP 14, RFC 2119, 591 DOI 10.17487/RFC2119, March 1997, 592 . 594 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 595 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 596 . 598 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 599 DOI 10.17487/RFC2818, May 2000, 600 . 602 [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related 603 Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, 604 . 606 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 607 "SEcure Neighbor Discovery (SEND)", RFC 3971, 608 DOI 10.17487/RFC3971, March 2005, 609 . 611 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 612 "Randomness Requirements for Security", BCP 106, RFC 4086, 613 DOI 10.17487/RFC4086, June 2005, 614 . 616 [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast 617 Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005, 618 . 620 [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, 621 "Internet X.509 Public Key Infrastructure Certificate 622 Management Protocol (CMP)", RFC 4210, 623 DOI 10.17487/RFC4210, September 2005, 624 . 626 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 627 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 628 2006, . 630 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 631 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 632 December 2005, . 634 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 635 DOI 10.17487/RFC4302, December 2005, 636 . 638 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 639 RFC 4303, DOI 10.17487/RFC4303, December 2005, 640 . 642 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 643 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 644 DOI 10.17487/RFC4861, September 2007, 645 . 647 [RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast 648 Extensions to the Security Architecture for the Internet 649 Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008, 650 . 652 [RFC5415] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, 653 Ed., "Control And Provisioning of Wireless Access Points 654 (CAPWAP) Protocol Specification", RFC 5415, 655 DOI 10.17487/RFC5415, March 2009, 656 . 658 [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing 659 Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889, 660 September 2010, . 662 [RFC6059] Krishnan, S. and G. Daley, "Simple Procedures for 663 Detecting Network Attachment in IPv6", RFC 6059, 664 DOI 10.17487/RFC6059, November 2010, 665 . 667 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 668 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 669 2011, . 671 [RFC7042] Eastlake 3rd, D. and J. Abley, "IANA Considerations and 672 IETF Protocol and Documentation Usage for IEEE 802 673 Parameters", BCP 141, RFC 7042, DOI 10.17487/RFC7042, 674 October 2013, . 676 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 677 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 678 February 2014, . 680 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 681 Interface Identifiers with IPv6 Stateless Address 682 Autoconfiguration (SLAAC)", RFC 7217, 683 DOI 10.17487/RFC7217, April 2014, 684 . 686 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 687 Considerations for IPv6 Address Generation Mechanisms", 688 RFC 7721, DOI 10.17487/RFC7721, March 2016, 689 . 691 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 692 "Recommendation on Stable IPv6 Interface Identifiers", 693 RFC 8064, DOI 10.17487/RFC8064, February 2017, 694 . 696 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 697 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 698 May 2017, . 700 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 701 (IPv6) Specification", STD 86, RFC 8200, 702 DOI 10.17487/RFC8200, July 2017, 703 . 705 9.2. Informative References 707 [ETSI-sec-archi] 708 "ETSI TS 102 940 V1.2.1 (2016-11), ETSI Technical 709 Specification, Intelligent Transport Systems (ITS); 710 Security; ITS communications security architecture and 711 security management, November 2016. Downloaded on 712 September 9th, 2017, freely available from ETSI website at 713 URL http://www.etsi.org/deliver/ 714 etsi_ts/102900_102999/102940/01.02.01_60/ 715 ts_102940v010201p.pdf". 717 [I-D.ietf-ipwave-vehicular-networking] 718 Jeong, J., "IP Wireless Access in Vehicular Environments 719 (IPWAVE): Problem Statement and Use Cases", draft-ietf- 720 ipwave-vehicular-networking-08 (work in progress), March 721 2019. 723 [I-D.ietf-mboned-ieee802-mcast-problems] 724 Perkins, C., McBride, M., Stanley, D., Kumari, W., and J. 725 Zuniga, "Multicast Considerations over IEEE 802 Wireless 726 Media", draft-ietf-mboned-ieee802-mcast-problems-05 (work 727 in progress), April 2019. 729 [IEEE-1609.2] 730 "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access 731 in Vehicular Environments (WAVE) -- Security Services for 732 Applications and Management Messages. Example URL 733 http://ieeexplore.ieee.org/document/7426684/ accessed on 734 August 17th, 2017.". 736 [IEEE-1609.3] 737 "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access 738 in Vehicular Environments (WAVE) -- Networking Services. 739 Example URL http://ieeexplore.ieee.org/document/7458115/ 740 accessed on August 17th, 2017.". 742 [IEEE-1609.4] 743 "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access 744 in Vehicular Environments (WAVE) -- Multi-Channel 745 Operation. Example URL 746 http://ieeexplore.ieee.org/document/7435228/ accessed on 747 August 17th, 2017.". 749 [IEEE-802.11-2016] 750 "IEEE Standard 802.11-2016 - IEEE Standard for Information 751 Technology - Telecommunications and information exchange 752 between systems Local and metropolitan area networks - 753 Specific requirements - Part 11: Wireless LAN Medium 754 Access Control (MAC) and Physical Layer (PHY) 755 Specifications. Status - Active Standard. Description 756 retrieved freely; the document itself is also freely 757 available, but with some difficulty (requires 758 registration); description and document retrieved on April 759 8th, 2019, starting from URL 760 https://standards.ieee.org/findstds/ 761 standard/802.11-2016.html". 763 [IEEE-802.11p-2010] 764 "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information 765 Technology - Telecommunications and information exchange 766 between systems - Local and metropolitan area networks - 767 Specific requirements, Part 11: Wireless LAN Medium Access 768 Control (MAC) and Physical Layer (PHY) Specifications, 769 Amendment 6: Wireless Access in Vehicular Environments; 770 document freely available at URL 771 http://standards.ieee.org/getieee802/ 772 download/802.11p-2010.pdf retrieved on September 20th, 773 2013.". 775 Appendix A. ChangeLog 777 The changes are listed in reverse chronological order, most recent 778 changes appearing at the top of the list. 780 -43: removed the SHOULD 48bit of a MAC address, just stay silent 781 about it; corrected 'global' address to 'Globally Reachable address'; 782 added a paragraph scoping IPv6-over-OCB ND to work ok on single-link 783 subnets. 785 -42: removed 118 len IID; points to 'other documents' for the length 786 of Interface ID; removed 'directly using' phrase for LLs in a subnet. 788 -41: updated a reference from draft-ietf-ipwave-vehicular-networking- 789 survey to draft-ietf-ipwave-vehicular-networking; clarified the link- 790 local text by eliminating link-local addresses and prefixes 791 altogether and referring to RFC4861 which requires the prefixes; 792 added a statement about the subnet being a not multi-link subnet. 794 -40: added a phrase in appendix to further described a condition 795 where ND on OCB may not work; that phrase contains a placeholder; the 796 placeholder is 'TBD' (To Be Defined). 798 -39: removed a reference to an expired draft trying to update the 799 IPv6-over-Ethernet spec 'RFC2464bis'; added text in the subnet 800 structure section saying nodes MUST be able to communicate directly 801 using their link-local addresses. 803 -38: removed the word "fe80::/10". 805 -37: added a section about issues on ND wireless; added the qualifier 806 'baseline' to using ND on 802.11-OCB; improved the description of the 807 reference to 802.11-2016 document, with a qualifier about the 808 difficulty of accessing it, even though it is free. 810 -36: removed a phrase about the IID formation and MAC generation, but 811 left in the section 5.2 that describes how it happens. 813 -35: addressing the the intarea review: clarified a small apparent 814 contradiction between two parts of text that use the old MAC-based 815 IIDs (clarified by using qualifiers from each other: transition time, 816 and ll addresses); sequenced closer the LL and Stateless Autoconf 817 sections, instead of spacing them; shortened the paragraph of Opaque 818 IIDs; moved the privacy risks of in-clear IIDs in the security 819 section; removed a short phrase duplicating the idea of privacy 820 risks; added third time a reference to the 802.11-2016 document; used 821 'the hidden terminal' text; updated the Terminology section with new 822 BCP-14 text 'MUST' to include RFC8174. 824 -33: substituted 'movement detection' for 'handover behaviour' in 825 introductory text; removed redundant phrase referring to Security 826 Considerations section; removed the phrase about forming mechanisms 827 being left out, as IP is not much concerned about L2 forming; moved 828 the Pseudonym section from main section to end of Security 829 Considerations section (and clarified 'concurrently'); capitalized 830 SHOULD consider OCB in WiFi multicast problems, and referred to more 831 recent I-D on topic; removed several phrases in a paragraph about 832 oui.txt and MAC presence in IPv6 address, as they are well known 833 info, but clarified the example of privacy risk of Company ID in MAC 834 addresses in public roads; clarified that ND MUST be used over 835 802.11-OCB. 837 -32: significantly shortened the relevant ND/OCB paragraph. It now 838 just states ND is used over OCB, w/o detailing. 840 -31: filled in the section titled "Pseudonym Handling"; removed a 841 'MAY NOT' phrase about possibility of having other prefix than the LL 842 on the link between cars; shortened and improved the paragraph about 843 Mobile IPv6, now with DNAv6; improved the ND text about ND 844 retransmissions with relationship to packet loss; changed the title 845 of an appendix from 'EPD' to 'Protocol Layering'; improved the 846 'Aspects introduced by OCB' appendix with a few phrases about the 847 channel use and references. 849 -30: a clarification on the reliability of ND over OCB and over 850 802.11. 852 -29: 854 o 856 -28: 858 o Created a new section 'Pseudonym Handling'. 860 o removed the 'Vehicle ID' appendix. 862 o improved the address generation from random MAC address. 864 o shortened Term IP-RSU definition. 866 o removed refs to two detail Clauses in IEEE documents, kept just 867 these latter. 869 -27: part 1 of addressing Human Rights review from IRTF. Removed 870 appendices F.2 and F.3. Shortened definition of IP-RSU. Removed 871 reference to 1609.4. A few other small changes, see diff. 873 -26: moved text from SLAAC section and from Design Considerations 874 appendix about privacy into a new Privacy Condiderations subsection 875 of the Security section; reformulated the SLAAC and IID sections to 876 stress only LLs can use EUI-64; removed the "GeoIP" wireshark 877 explanation; reformulated SLAAC and LL sections; added brief mention 878 of need of use LLs; clarified text about MAC address changes; dropped 879 pseudonym discussion; changed title of section describing examples of 880 packet formats. 882 -25: added a reference to 'IEEE Management Information Base', instead 883 of just 'Management Information Base'; added ref to further 884 appendices in the introductory phrases; improved text for IID 885 formation for SLAAC, inserting recommendation for RFC8064 before 886 RFC2464. 888 From draft-ietf-ipwave-ipv6-over-80211ocb-23 to draft-ietf-ipwave- 889 ipv6-over-80211ocb-24 891 o Nit: wrote "IPWAVE Working Group" on the front page, instead of 892 "Network Working Group". 894 o Addressed the comments on 6MAN: replaced a sentence about ND 895 problem with "is used over 802.11-OCB". 897 From draft-ietf-ipwave-ipv6-over-80211ocb-22 to draft-ietf-ipwave- 898 ipv6-over-80211ocb-23 900 o No content modifications, but check the entire draft chain on 901 IPv6-only: xml2rfc, submission on tools.ietf.org and datatracker. 903 From draft-ietf-ipwave-ipv6-over-80211ocb-21 to draft-ietf-ipwave- 904 ipv6-over-80211ocb-22 906 o Corrected typo, use dash in "802.11-OCB" instead of space. 908 o Improved the Frame Format section: MUST use QoSData, specify the 909 values within; clarified the Ethernet Adaptation Layer text. 911 From draft-ietf-ipwave-ipv6-over-80211ocb-20 to draft-ietf-ipwave- 912 ipv6-over-80211ocb-21 914 o Corrected a few nits and added names in Acknowledgments section. 916 o Removed unused reference to old Internet Draft tsvwg about QoS. 918 From draft-ietf-ipwave-ipv6-over-80211ocb-19 to draft-ietf-ipwave- 919 ipv6-over-80211ocb-20 921 o Reduced the definition of term "802.11-OCB". 923 o Left out of this specification which 802.11 header to use to 924 transmit IP packets in OCB mode (QoS Data header, Data header, or 925 any other). 927 o Added 'MUST' use an Ethernet Adaptation Layer, instead of 'is 928 using' an Ethernet Adaptation Layer. 930 From draft-ietf-ipwave-ipv6-over-80211ocb-18 to draft-ietf-ipwave- 931 ipv6-over-80211ocb-19 933 o Removed the text about fragmentation. 935 o Removed the mentioning of WSMP and GeoNetworking. 937 o Removed the explanation of the binary representation of the 938 EtherType. 940 o Rendered normative the paragraph about unicast and multicast 941 address mapping. 943 o Removed paragraph about addressing model, subnet structure and 944 easiness of using LLs. 946 o Clarified the Type/Subtype field in the 802.11 Header. 948 o Used RECOMMENDED instead of recommended, for the stable interface 949 identifiers. 951 From draft-ietf-ipwave-ipv6-over-80211ocb-17 to draft-ietf-ipwave- 952 ipv6-over-80211ocb-18 954 o Improved the MTU and fragmentation paragraph. 956 From draft-ietf-ipwave-ipv6-over-80211ocb-16 to draft-ietf-ipwave- 957 ipv6-over-80211ocb-17 959 o Susbtituted "MUST be increased" to "is increased" in the MTU 960 section, about fragmentation. 962 From draft-ietf-ipwave-ipv6-over-80211ocb-15 to draft-ietf-ipwave- 963 ipv6-over-80211ocb-16 965 o Removed the definition of the 'WiFi' term and its occurences. 966 Clarified a phrase that used it in Appendix C "Aspects introduced 967 by the OCB mode to 802.11". 969 o Added more normative words: MUST be 0x86DD, MUST fragment if size 970 larger than MTU, Sequence number in 802.11 Data header MUST be 971 increased. 973 From draft-ietf-ipwave-ipv6-over-80211ocb-14 to draft-ietf-ipwave- 974 ipv6-over-80211ocb-15 976 o Added normative term MUST in two places in section "Ethernet 977 Adaptation Layer". 979 From draft-ietf-ipwave-ipv6-over-80211ocb-13 to draft-ietf-ipwave- 980 ipv6-over-80211ocb-14 982 o Created a new Appendix titled "Extra Terminology" that contains 983 terms DSRC, DSRCS, OBU, RSU as defined outside IETF. Some of them 984 are used in the main Terminology section. 986 o Added two paragraphs explaining that ND and Mobile IPv6 have 987 problems working over 802.11-OCB, yet their adaptations is not 988 specified in this document. 990 From draft-ietf-ipwave-ipv6-over-80211ocb-12 to draft-ietf-ipwave- 991 ipv6-over-80211ocb-13 993 o Substituted "IP-OBU" for "OBRU", and "IP-RSU" for "RSRU" 994 throughout and improved OBU-related definitions in the Terminology 995 section. 997 From draft-ietf-ipwave-ipv6-over-80211ocb-11 to draft-ietf-ipwave- 998 ipv6-over-80211ocb-12 1000 o Improved the appendix about "MAC Address Generation" by expressing 1001 the technique to be an optional suggestion, not a mandatory 1002 mechanism. 1004 From draft-ietf-ipwave-ipv6-over-80211ocb-10 to draft-ietf-ipwave- 1005 ipv6-over-80211ocb-11 1007 o Shortened the paragraph on forming/terminating 802.11-OCB links. 1009 o Moved the draft tsvwg-ieee-802-11 to Informative References. 1011 From draft-ietf-ipwave-ipv6-over-80211ocb-09 to draft-ietf-ipwave- 1012 ipv6-over-80211ocb-10 1014 o Removed text requesting a new Group ID for multicast for OCB. 1016 o Added a clarification of the meaning of value "3333" in the 1017 section Address Mapping -- Multicast. 1019 o Added note clarifying that in Europe the regional authority is not 1020 ETSI, but "ECC/CEPT based on ENs from ETSI". 1022 o Added note stating that the manner in which two STAtions set their 1023 communication channel is not described in this document. 1025 o Added a time qualifier to state that the "each node is represented 1026 uniquely at a certain point in time." 1028 o Removed text "This section may need to be moved" (the "Reliability 1029 Requirements" section). This section stays there at this time. 1031 o In the term definition "802.11-OCB" added a note stating that "any 1032 implementation should comply with standards and regulations set in 1033 the different countries for using that frequency band." 1035 o In the RSU term definition, added a sentence explaining the 1036 difference between RSU and RSRU: in terms of number of interfaces 1037 and IP forwarding. 1039 o Replaced "with at least two IP interfaces" with "with at least two 1040 real or virtual IP interfaces". 1042 o Added a term in the Terminology for "OBU". However the definition 1043 is left empty, as this term is defined outside IETF. 1045 o Added a clarification that it is an OBU or an OBRU in this phrase 1046 "A vehicle embarking an OBU or an OBRU". 1048 o Checked the entire document for a consistent use of terms OBU and 1049 OBRU. 1051 o Added note saying that "'p' is a letter identifying the 1052 Ammendment". 1054 o Substituted lower case for capitals SHALL or MUST in the 1055 Appendices. 1057 o Added reference to RFC7042, helpful in the 3333 explanation. 1058 Removed reference to individual submission draft-petrescu-its- 1059 scenario-reqs and added reference to draft-ietf-ipwave-vehicular- 1060 networking-survey. 1062 o Added figure captions, figure numbers, and references to figure 1063 numbers instead of 'below'. Replaced "section Section" with 1064 "section" throughout. 1066 o Minor typographical errors. 1068 From draft-ietf-ipwave-ipv6-over-80211ocb-08 to draft-ietf-ipwave- 1069 ipv6-over-80211ocb-09 1071 o Significantly shortened the Address Mapping sections, by text 1072 copied from RFC2464, and rather referring to it. 1074 o Moved the EPD description to an Appendix on its own. 1076 o Shortened the Introduction and the Abstract. 1078 o Moved the tutorial section of OCB mode introduced to .11, into an 1079 appendix. 1081 o Removed the statement that suggests that for routing purposes a 1082 prefix exchange mechanism could be needed. 1084 o Removed refs to RFC3963, RFC4429 and RFC6775; these are about ND, 1085 MIP/NEMO and oDAD; they were referred in the handover discussion 1086 section, which is out. 1088 o Updated a reference from individual submission to now a WG item in 1089 IPWAVE: the survey document. 1091 o Added term definition for WiFi. 1093 o Updated the authorship and expanded the Contributors section. 1095 o Corrected typographical errors. 1097 From draft-ietf-ipwave-ipv6-over-80211ocb-07 to draft-ietf-ipwave- 1098 ipv6-over-80211ocb-08 1100 o Removed the per-channel IPv6 prohibition text. 1102 o Corrected typographical errors. 1104 From draft-ietf-ipwave-ipv6-over-80211ocb-06 to draft-ietf-ipwave- 1105 ipv6-over-80211ocb-07 1107 o Added new terms: OBRU and RSRU ('R' for Router). Refined the 1108 existing terms RSU and OBU, which are no longer used throughout 1109 the document. 1111 o Improved definition of term "802.11-OCB". 1113 o Clarified that OCB does not "strip" security, but that the 1114 operation in OCB mode is "stripped off of all .11 security". 1116 o Clarified that theoretical OCB bandwidth speed is 54mbits, but 1117 that a commonly observed bandwidth in IP-over-OCB is 12mbit/s. 1119 o Corrected typographical errors, and improved some phrasing. 1121 From draft-ietf-ipwave-ipv6-over-80211ocb-05 to draft-ietf-ipwave- 1122 ipv6-over-80211ocb-06 1124 o Updated references of 802.11-OCB document from -2012 to the IEEE 1125 802.11-2016. 1127 o In the LL address section, and in SLAAC section, added references 1128 to 7217 opaque IIDs and 8064 stable IIDs. 1130 From draft-ietf-ipwave-ipv6-over-80211ocb-04 to draft-ietf-ipwave- 1131 ipv6-over-80211ocb-05 1133 o Lengthened the title and cleanded the abstract. 1135 o Added text suggesting LLs may be easy to use on OCB, rather than 1136 GUAs based on received prefix. 1138 o Added the risks of spoofing and hijacking. 1140 o Removed the text speculation on adoption of the TSA message. 1142 o Clarified that the ND protocol is used. 1144 o Clarified what it means "No association needed". 1146 o Added some text about how two STAs discover each other. 1148 o Added mention of external (OCB) and internal network (stable), in 1149 the subnet structure section. 1151 o Added phrase explaining that both .11 Data and .11 QoS Data 1152 headers are currently being used, and may be used in the future. 1154 o Moved the packet capture example into an Appendix Implementation 1155 Status. 1157 o Suggested moving the reliability requirements appendix out into 1158 another document. 1160 o Added a IANA Consiserations section, with content, requesting for 1161 a new multicast group "all OCB interfaces". 1163 o Added new OBU term, improved the RSU term definition, removed the 1164 ETTC term, replaced more occurences of 802.11p, 802.11-OCB with 1165 802.11-OCB. 1167 o References: 1169 * Added an informational reference to ETSI's IPv6-over- 1170 GeoNetworking. 1172 * Added more references to IETF and ETSI security protocols. 1174 * Updated some references from I-D to RFC, and from old RFC to 1175 new RFC numbers. 1177 * Added reference to multicast extensions to IPsec architecture 1178 RFC. 1180 * Added a reference to 2464-bis. 1182 * Removed FCC informative references, because not used. 1184 o Updated the affiliation of one author. 1186 o Reformulation of some phrases for better readability, and 1187 correction of typographical errors. 1189 From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave- 1190 ipv6-over-80211ocb-04 1192 o Removed a few informative references pointing to Dx draft IEEE 1193 1609 documents. 1195 o Removed outdated informative references to ETSI documents. 1197 o Added citations to IEEE 1609.2, .3 and .4-2016. 1199 o Minor textual issues. 1201 From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave- 1202 ipv6-over-80211ocb-03 1204 o Keep the previous text on multiple addresses, so remove talk about 1205 MIP6, NEMOv6 and MCoA. 1207 o Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon. 1209 o Clarified the figure showing Infrastructure mode and OCB mode side 1210 by side. 1212 o Added a reference to the IP Security Architecture RFC. 1214 o Detailed the IPv6-per-channel prohibition paragraph which reflects 1215 the discussion at the last IETF IPWAVE WG meeting. 1217 o Added section "Address Mapping -- Unicast". 1219 o Added the ".11 Trailer" to pictures of 802.11 frames. 1221 o Added text about SNAP carrying the Ethertype. 1223 o New RSU definition allowing for it be both a Router and not 1224 necessarily a Router some times. 1226 o Minor textual issues. 1228 From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave- 1229 ipv6-over-80211ocb-02 1230 o Replaced almost all occurences of 802.11p with 802.11-OCB, leaving 1231 only when explanation of evolution was necessary. 1233 o Shortened by removing parameter details from a paragraph in the 1234 Introduction. 1236 o Moved a reference from Normative to Informative. 1238 o Added text in intro clarifying there is no handover spec at IEEE, 1239 and that 1609.2 does provide security services. 1241 o Named the contents the fields of the EthernetII header (including 1242 the Ethertype bitstring). 1244 o Improved relationship between two paragraphs describing the 1245 increase of the Sequence Number in 802.11 header upon IP 1246 fragmentation. 1248 o Added brief clarification of "tracking". 1250 From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave- 1251 ipv6-over-80211ocb-01 1253 o Introduced message exchange diagram illustrating differences 1254 between 802.11 and 802.11 in OCB mode. 1256 o Introduced an appendix listing for information the set of 802.11 1257 messages that may be transmitted in OCB mode. 1259 o Removed appendix sections "Privacy Requirements", "Authentication 1260 Requirements" and "Security Certificate Generation". 1262 o Removed appendix section "Non IP Communications". 1264 o Introductory phrase in the Security Considerations section. 1266 o Improved the definition of "OCB". 1268 o Introduced theoretical stacked layers about IPv6 and IEEE layers 1269 including EPD. 1271 o Removed the appendix describing the details of prohibiting IPv6 on 1272 certain channels relevant to 802.11-OCB. 1274 o Added a brief reference in the privacy text about a precise clause 1275 in IEEE 1609.3 and .4. 1277 o Clarified the definition of a Road Side Unit. 1279 o Removed the discussion about security of WSA (because is non-IP). 1281 o Removed mentioning of the GeoNetworking discussion. 1283 o Moved references to scientific articles to a separate 'overview' 1284 draft, and referred to it. 1286 Appendix B. 802.11p 1288 The term "802.11p" is an earlier definition. The behaviour of 1289 "802.11p" networks is rolled in the document IEEE Std 802.11-2016. 1290 In that document the term 802.11p disappears. Instead, each 802.11p 1291 feature is conditioned by the IEEE Management Information Base (MIB) 1292 attribute "OCBActivated" [IEEE-802.11-2016]. Whenever OCBActivated 1293 is set to true the IEEE Std 802.11-OCB state is activated. For 1294 example, an 802.11 STAtion operating outside the context of a basic 1295 service set has the OCBActivated flag set. Such a station, when it 1296 has the flag set, uses a BSS identifier equal to ff:ff:ff:ff:ff:ff. 1298 Appendix C. Aspects introduced by the OCB mode to 802.11 1300 In the IEEE 802.11-OCB mode, all nodes in the wireless range can 1301 directly communicate with each other without involving authentication 1302 or association procedures. In OCB mode, the manner in which channels 1303 are selected and used is simplified compared to when in BSS mode. 1304 Contrary to BSS mode, at link layer, it is necessary to set 1305 statically the same channel number (or frequency) on two stations 1306 that need to communicate with each other (in BSS mode this channel 1307 set operation is performed automatically during 'scanning'). The 1308 manner in which stations set their channel number in OCB mode is not 1309 specified in this document. Stations STA1 and STA2 can exchange IP 1310 packets only if they are set on the same channel. At IP layer, they 1311 then discover each other by using the IPv6 Neighbor Discovery 1312 protocol. The allocation of a particular channel for a particular 1313 use is defined statically in standards authored by ETSI (in Europe), 1314 FCC in America, and similar organisations in South Korea, Japan and 1315 other parts of the world. 1317 Briefly, the IEEE 802.11-OCB mode has the following properties: 1319 o The use by each node of a 'wildcard' BSSID (i.e., each bit of the 1320 BSSID is set to 1) 1322 o No IEEE 802.11 Beacon frames are transmitted 1324 o No authentication is required in order to be able to communicate 1326 o No association is needed in order to be able to communicate 1327 o No encryption is provided in order to be able to communicate 1329 o Flag dot11OCBActivated is set to true 1331 All the nodes in the radio communication range (IP-OBU and IP-RSU) 1332 receive all the messages transmitted (IP-OBU and IP-RSU) within the 1333 radio communications range. The eventual conflict(s) are resolved by 1334 the MAC CDMA function. 1336 The message exchange diagram in Figure 3 illustrates a comparison 1337 between traditional 802.11 and 802.11 in OCB mode. The 'Data' 1338 messages can be IP packets such as HTTP or others. Other 802.11 1339 management and control frames (non IP) may be transmitted, as 1340 specified in the 802.11 standard. For information, the names of 1341 these messages as currently specified by the 802.11 standard are 1342 listed in Appendix G. 1344 STA AP STA1 STA2 1345 | | | | 1346 |<------ Beacon -------| |<------ Data -------->| 1347 | | | | 1348 |---- Probe Req. ----->| |<------ Data -------->| 1349 |<--- Probe Res. ------| | | 1350 | | |<------ Data -------->| 1351 |---- Auth Req. ------>| | | 1352 |<--- Auth Res. -------| |<------ Data -------->| 1353 | | | | 1354 |---- Asso Req. ------>| |<------ Data -------->| 1355 |<--- Asso Res. -------| | | 1356 | | |<------ Data -------->| 1357 |<------ Data -------->| | | 1358 |<------ Data -------->| |<------ Data -------->| 1360 (i) 802.11 Infrastructure mode (ii) 802.11-OCB mode 1362 Figure 3: Difference between messages exchanged on 802.11 (left) and 1363 802.11-OCB (right) 1365 The interface 802.11-OCB was specified in IEEE Std 802.11p (TM) -2010 1366 [IEEE-802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, 1367 titled "Amendment 6: Wireless Access in Vehicular Environments". 1368 Since then, this amendment has been integrated in IEEE 802.11(TM) 1369 -2012 and -2016 [IEEE-802.11-2016]. 1371 In document 802.11-2016, anything qualified specifically as 1372 "OCBActivated", or "outside the context of a basic service" set to be 1373 true, then it is actually referring to OCB aspects introduced to 1374 802.11. 1376 In order to delineate the aspects introduced by 802.11-OCB to 802.11, 1377 we refer to the earlier [IEEE-802.11p-2010]. The amendment is 1378 concerned with vehicular communications, where the wireless link is 1379 similar to that of Wireless LAN (using a PHY layer specified by 1380 802.11a/b/g/n), but which needs to cope with the high mobility factor 1381 inherent in scenarios of communications between moving vehicles, and 1382 between vehicles and fixed infrastructure deployed along roads. 1383 While 'p' is a letter identifying the Ammendment, just like 'a, b, g' 1384 and 'n' are, 'p' is concerned more with MAC modifications, and a 1385 little with PHY modifications; the others are mainly about PHY 1386 modifications. It is possible in practice to combine a 'p' MAC with 1387 an 'a' PHY by operating outside the context of a BSS with OFDM at 1388 5.4GHz and 5.9GHz. 1390 The 802.11-OCB links are specified to be compatible as much as 1391 possible with the behaviour of 802.11a/b/g/n and future generation 1392 IEEE WLAN links. From the IP perspective, an 802.11-OCB MAC layer 1393 offers practically the same interface to IP as the 802.11a/b/g/n and 1394 802.3. A packet sent by an IP-OBU may be received by one or multiple 1395 IP-RSUs. The link-layer resolution is performed by using the IPv6 1396 Neighbor Discovery protocol. 1398 To support this similarity statement (IPv6 is layered on top of LLC 1399 on top of 802.11-OCB, in the same way that IPv6 is layered on top of 1400 LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on 1401 top of 802.3 (for Ethernet)) it is useful to analyze the differences 1402 between 802.11-OCB and 802.11 specifications. During this analysis, 1403 we note that whereas 802.11-OCB lists relatively complex and numerous 1404 changes to the MAC layer (and very little to the PHY layer), there 1405 are only a few characteristics which may be important for an 1406 implementation transmitting IPv6 packets on 802.11-OCB links. 1408 The most important 802.11-OCB point which influences the IPv6 1409 functioning is the OCB characteristic; an additional, less direct 1410 influence, is the maximum bandwidth afforded by the PHY modulation/ 1411 demodulation methods and channel access specified by 802.11-OCB. The 1412 maximum bandwidth theoretically possible in 802.11-OCB is 54 Mbit/s 1413 (when using, for example, the following parameters: 20 MHz channel; 1414 modulation 64-QAM; coding rate R is 3/4); in practice of IP-over- 1415 802.11-OCB a commonly observed figure is 12Mbit/s; this bandwidth 1416 allows the operation of a wide range of protocols relying on IPv6. 1418 o Operation Outside the Context of a BSS (OCB): the (earlier 1419 802.11p) 802.11-OCB links are operated without a Basic Service Set 1420 (BSS). This means that the frames IEEE 802.11 Beacon, Association 1421 Request/Response, Authentication Request/Response, and similar, 1422 are not used. The used identifier of BSS (BSSID) has a 1423 hexadecimal value always 0xffffffffffff (48 '1' bits, represented 1424 as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' 1425 BSSID), as opposed to an arbitrary BSSID value set by 1426 administrator (e.g. 'My-Home-AccessPoint'). The OCB operation - 1427 namely the lack of beacon-based scanning and lack of 1428 authentication - should be taken into account when the Mobile IPv6 1429 protocol [RFC6275] and the protocols for IP layer security 1430 [RFC4301] are used. The way these protocols adapt to OCB is not 1431 described in this document. 1433 o Timing Advertisement: is a new message defined in 802.11-OCB, 1434 which does not exist in 802.11a/b/g/n. This message is used by 1435 stations to inform other stations about the value of time. It is 1436 similar to the time as delivered by a GNSS system (Galileo, GPS, 1437 ...) or by a cellular system. This message is optional for 1438 implementation. 1440 o Frequency range: this is a characteristic of the PHY layer, with 1441 almost no impact on the interface between MAC and IP. However, it 1442 is worth considering that the frequency range is regulated by a 1443 regional authority (ARCEP, ECC/CEPT based on ENs from ETSI, FCC, 1444 etc.); as part of the regulation process, specific applications 1445 are associated with specific frequency ranges. In the case of 1446 802.11-OCB, the regulator associates a set of frequency ranges, or 1447 slots within a band, to the use of applications of vehicular 1448 communications, in a band known as "5.9GHz". The 5.9GHz band is 1449 different from the 2.4GHz and 5GHz bands used by Wireless LAN. 1450 However, as with Wireless LAN, the operation of 802.11-OCB in 1451 "5.9GHz" bands is exempt from owning a license in EU (in US the 1452 5.9GHz is a licensed band of spectrum; for the fixed 1453 infrastructure an explicit FCC authorization is required; for an 1454 on-board device a 'licensed-by-rule' concept applies: rule 1455 certification conformity is required.) Technical conditions are 1456 different than those of the bands "2.4GHz" or "5GHz". The allowed 1457 power levels, and implicitly the maximum allowed distance between 1458 vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20 1459 dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum 1460 distance of approximately 1km, compared to approximately 50m. 1461 Additionally, specific conditions related to congestion avoidance, 1462 jamming avoidance, and radar detection are imposed on the use of 1463 DSRC (in US) and on the use of frequencies for Intelligent 1464 Transportation Systems (in EU), compared to Wireless LAN 1465 (802.11a/b/g/n). 1467 o 'Half-rate' encoding: as the frequency range, this parameter is 1468 related to PHY, and thus has not much impact on the interface 1469 between the IP layer and the MAC layer. 1471 o In vehicular communications using 802.11-OCB links, there are 1472 strong privacy requirements with respect to addressing. While the 1473 802.11-OCB standard does not specify anything in particular with 1474 respect to MAC addresses, in these settings there exists a strong 1475 need for dynamic change of these addresses (as opposed to the non- 1476 vehicular settings - real wall protection - where fixed MAC 1477 addresses do not currently pose some privacy risks). This is 1478 further described in Section 5. A relevant function is described 1479 in documents IEEE 1609.3-2016 [IEEE-1609.3] and IEEE 1609.4-2016 1480 [IEEE-1609.4]. 1482 Appendix D. Changes Needed on a software driver 802.11a to become a 1483 802.11-OCB driver 1485 The 802.11p amendment modifies both the 802.11 stack's physical and 1486 MAC layers but all the induced modifications can be quite easily 1487 obtained by modifying an existing 802.11a ad-hoc stack. 1489 Conditions for a 802.11a hardware to be 802.11-OCB compliant: 1491 o The PHY entity shall be an orthogonal frequency division 1492 multiplexing (OFDM) system. It must support the frequency bands 1493 on which the regulator recommends the use of ITS communications, 1494 for example using IEEE 802.11-OCB layer, in France: 5875MHz to 1495 5925MHz. 1497 o The OFDM system must provide a "half-clocked" operation using 10 1498 MHz channel spacings. 1500 o The chip transmit spectrum mask must be compliant to the "Transmit 1501 spectrum mask" from the IEEE 802.11p amendment (but experimental 1502 environments tolerate otherwise). 1504 o The chip should be able to transmit up to 44.8 dBm when used by 1505 the US government in the United States, and up to 33 dBm in 1506 Europe; other regional conditions apply. 1508 Changes needed on the network stack in OCB mode: 1510 o Physical layer: 1512 * The chip must use the Orthogonal Frequency Multiple Access 1513 (OFDM) encoding mode. 1515 * The chip must be set in half-mode rate mode (the internal clock 1516 frequency is divided by two). 1518 * The chip must use dedicated channels and should allow the use 1519 of higher emission powers. This may require modifications to 1520 the local computer file that describes regulatory domains 1521 rules, if used by the kernel to enforce local specific 1522 restrictions. Such modifications to the local computer file 1523 must respect the location-specific regulatory rules. 1525 MAC layer: 1527 * All management frames (beacons, join, leave, and others) 1528 emission and reception must be disabled except for frames of 1529 subtype Action and Timing Advertisement (defined below). 1531 * No encryption key or method must be used. 1533 * Packet emission and reception must be performed as in ad-hoc 1534 mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff). 1536 * The functions related to joining a BSS (Association Request/ 1537 Response) and for authentication (Authentication Request/Reply, 1538 Challenge) are not called. 1540 * The beacon interval is always set to 0 (zero). 1542 * Timing Advertisement frames, defined in the amendment, should 1543 be supported. The upper layer should be able to trigger such 1544 frames emission and to retrieve information contained in 1545 received Timing Advertisements. 1547 Appendix E. Protocol Layering 1549 A more theoretical and detailed view of layer stacking, and 1550 interfaces between the IP layer and 802.11-OCB layers, is illustrated 1551 in Figure 4. The IP layer operates on top of the EtherType Protocol 1552 Discrimination (EPD); this Discrimination layer is described in IEEE 1553 Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP 1554 (Link Layer Control Service Access Point). 1556 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1557 | IPv6 | 1558 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ 1559 { LLC_SAP } 802.11-OCB 1560 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary 1561 | EPD | | | 1562 | | MLME | | 1563 +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | 1564 | MAC Sublayer | | | 802.11-OCB 1565 | and ch. coord. | | SME | Services 1566 +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | 1567 | | PLME | | 1568 | PHY Layer | PLME_SAP | 1569 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1571 Figure 4: EtherType Protocol Discrimination 1573 Appendix F. Design Considerations 1575 The networks defined by 802.11-OCB are in many ways similar to other 1576 networks of the 802.11 family. In theory, the encapsulation of IPv6 1577 over 802.11-OCB could be very similar to the operation of IPv6 over 1578 other networks of the 802.11 family. However, the high mobility, 1579 strong link asymmetry and very short connection makes the 802.11-OCB 1580 link significantly different from other 802.11 networks. Also, the 1581 automotive applications have specific requirements for reliability, 1582 security and privacy, which further add to the particularity of the 1583 802.11-OCB link. 1585 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode 1587 For information, at the time of writing, this is the list of IEEE 1588 802.11 messages that may be transmitted in OCB mode, i.e. when 1589 dot11OCBActivated is true in a STA: 1591 o The STA may send management frames of subtype Action and, if the 1592 STA maintains a TSF Timer, subtype Timing Advertisement; 1594 o The STA may send control frames, except those of subtype PS-Poll, 1595 CF-End, and CF-End plus CFAck; 1597 o The STA may send data frames of subtype Data, Null, QoS Data, and 1598 QoS Null. 1600 Appendix H. Examples of Packet Formats 1602 This section describes an example of an IPv6 Packet captured over a 1603 IEEE 802.11-OCB link. 1605 By way of example we show that there is no modification in the 1606 headers when transmitted over 802.11-OCB networks - they are 1607 transmitted like any other 802.11 and Ethernet packets. 1609 We describe an experiment of capturing an IPv6 packet on an 1610 802.11-OCB link. In topology depicted in Figure 5, the packet is an 1611 IPv6 Router Advertisement. This packet is emitted by a Router on its 1612 802.11-OCB interface. The packet is captured on the Host, using a 1613 network protocol analyzer (e.g. Wireshark); the capture is performed 1614 in two different modes: direct mode and 'monitor' mode. The topology 1615 used during the capture is depicted below. 1617 The packet is captured on the Host. The Host is an IP-OBU containing 1618 an 802.11 interface in format PCI express (an ITRI product). The 1619 kernel runs the ath5k software driver with modifications for OCB 1620 mode. The capture tool is Wireshark. The file format for save and 1621 analyze is 'pcap'. The packet is generated by the Router. The 1622 Router is an IP-RSU (ITRI product). 1624 +--------+ +-------+ 1625 | | 802.11-OCB Link | | 1626 ---| Router |--------------------------------| Host | 1627 | | | | 1628 +--------+ +-------+ 1630 Figure 5: Topology for capturing IP packets on 802.11-OCB 1632 During several capture operations running from a few moments to 1633 several hours, no message relevant to the BSSID contexts were 1634 captured (no Association Request/Response, Authentication Req/Resp, 1635 Beacon). This shows that the operation of 802.11-OCB is outside the 1636 context of a BSSID. 1638 Overall, the captured message is identical with a capture of an IPv6 1639 packet emitted on a 802.11b interface. The contents are precisely 1640 similar. 1642 H.1. Capture in Monitor Mode 1644 The IPv6 RA packet captured in monitor mode is illustrated below. 1645 The radio tap header provides more flexibility for reporting the 1646 characteristics of frames. The Radiotap Header is prepended by this 1647 particular stack and operating system on the Host machine to the RA 1648 packet received from the network (the Radiotap Header is not present 1649 on the air). The implementation-dependent Radiotap Header is useful 1650 for piggybacking PHY information from the chip's registers as data in 1651 a packet understandable by userland applications using Socket 1652 interfaces (the PHY interface can be, for example: power levels, data 1653 rate, ratio of signal to noise). 1655 The packet present on the air is formed by IEEE 802.11 Data Header, 1656 Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. 1658 Radiotap Header v0 1659 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1660 |Header Revision| Header Pad | Header length | 1661 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1662 | Present flags | 1663 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1664 | Data Rate | Pad | 1665 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1667 IEEE 802.11 Data Header 1668 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1669 | Type/Subtype and Frame Ctrl | Duration | 1670 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1671 | Receiver Address... 1672 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1673 ... Receiver Address | Transmitter Address... 1674 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1675 ... Transmitter Address | 1676 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1677 | BSS Id... 1678 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1679 ... BSS Id | Frag Number and Seq Number | 1680 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1682 Logical-Link Control Header 1683 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1684 | DSAP |I| SSAP |C| Control field | Org. code... 1685 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1686 ... Organizational Code | Type | 1687 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1688 IPv6 Base Header 1689 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1690 |Version| Traffic Class | Flow Label | 1691 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1692 | Payload Length | Next Header | Hop Limit | 1693 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1694 | | 1695 + + 1696 | | 1697 + Source Address + 1698 | | 1699 + + 1700 | | 1701 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1702 | | 1703 + + 1704 | | 1705 + Destination Address + 1706 | | 1707 + + 1708 | | 1709 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1711 Router Advertisement 1712 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1713 | Type | Code | Checksum | 1714 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1715 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1716 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1717 | Reachable Time | 1718 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1719 | Retrans Timer | 1720 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1721 | Options ... 1722 +-+-+-+-+-+-+-+-+-+-+-+- 1724 The value of the Data Rate field in the Radiotap header is set to 6 1725 Mb/s. This indicates the rate at which this RA was received. 1727 The value of the Transmitter address in the IEEE 802.11 Data Header 1728 is set to a 48bit value. The value of the destination address is 1729 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS 1730 Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network 1731 protocol analyzer as being "broadcast". The Fragment number and 1732 sequence number fields are together set to 0x90C6. 1734 The value of the Organization Code field in the Logical-Link Control 1735 Header is set to 0x0, recognized as "Encapsulated Ethernet". The 1736 value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise 1737 #86DD), recognized as "IPv6". 1739 A Router Advertisement is periodically sent by the router to 1740 multicast group address ff02::1. It is an icmp packet type 134. The 1741 IPv6 Neighbor Discovery's Router Advertisement message contains an 1742 8-bit field reserved for single-bit flags, as described in [RFC4861]. 1744 The IPv6 header contains the link local address of the router 1745 (source) configured via EUI-64 algorithm, and destination address set 1746 to ff02::1. 1748 The Ethernet Type field in the logical-link control header is set to 1749 0x86dd which indicates that the frame transports an IPv6 packet. In 1750 the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 1751 which is the corresponding multicast MAC address. The BSS id is a 1752 broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link 1753 duration between vehicles and the roadside infrastructure, there is 1754 no need in IEEE 802.11-OCB to wait for the completion of association 1755 and authentication procedures before exchanging data. IEEE 1756 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) 1757 and may start communicating as soon as they arrive on the 1758 communication channel. 1760 H.2. Capture in Normal Mode 1762 The same IPv6 Router Advertisement packet described above (monitor 1763 mode) is captured on the Host, in the Normal mode, and depicted 1764 below. 1766 Ethernet II Header 1767 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1768 | Destination... 1769 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1770 ...Destination | Source... 1771 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1772 ...Source | 1773 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1774 | Type | 1775 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1777 IPv6 Base Header 1778 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1779 |Version| Traffic Class | Flow Label | 1780 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1781 | Payload Length | Next Header | Hop Limit | 1782 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1783 | | 1784 + + 1785 | | 1786 + Source Address + 1787 | | 1788 + + 1789 | | 1790 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1791 | | 1792 + + 1793 | | 1794 + Destination Address + 1795 | | 1796 + + 1797 | | 1798 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1800 Router Advertisement 1801 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1802 | Type | Code | Checksum | 1803 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1804 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1805 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1806 | Reachable Time | 1807 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1808 | Retrans Timer | 1809 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1810 | Options ... 1811 +-+-+-+-+-+-+-+-+-+-+-+- 1813 One notices that the Radiotap Header, the IEEE 802.11 Data Header and 1814 the Logical-Link Control Headers are not present. On the other hand, 1815 a new header named Ethernet II Header is present. 1817 The Destination and Source addresses in the Ethernet II header 1818 contain the same values as the fields Receiver Address and 1819 Transmitter Address present in the IEEE 802.11 Data Header in the 1820 "monitor" mode capture. 1822 The value of the Type field in the Ethernet II header is 0x86DD 1823 (recognized as "IPv6"); this value is the same value as the value of 1824 the field Type in the Logical-Link Control Header in the "monitor" 1825 mode capture. 1827 The knowledgeable experimenter will no doubt notice the similarity of 1828 this Ethernet II Header with a capture in normal mode on a pure 1829 Ethernet cable interface. 1831 An Adaptation layer is inserted on top of a pure IEEE 802.11 MAC 1832 layer, in order to adapt packets, before delivering the payload data 1833 to the applications. It adapts 802.11 LLC/MAC headers to Ethernet II 1834 headers. In further detail, this adaptation consists in the 1835 elimination of the Radiotap, 802.11 and LLC headers, and in the 1836 insertion of the Ethernet II header. In this way, IPv6 runs straight 1837 over LLC over the 802.11-OCB MAC layer; this is further confirmed by 1838 the use of the unique Type 0x86DD. 1840 Appendix I. Extra Terminology 1842 The following terms are defined outside the IETF. They are used to 1843 define the main terms in the main terminology section Section 2. 1845 DSRC (Dedicated Short Range Communication): a term defined outside 1846 the IETF. The US Federal Communications Commission (FCC) Dedicated 1847 Short Range Communication (DSRC) is defined in the Code of Federal 1848 Regulations (CFR) 47, Parts 90 and 95. This Code is referred in the 1849 definitions below. At the time of the writing of this Internet 1850 Draft, the last update of this Code was dated October 1st, 2010. 1852 DSRCS (Dedicated Short-Range Communications Services): a term defined 1853 outside the IETF. The use of radio techniques to transfer data over 1854 short distances between roadside and mobile units, between mobile 1855 units, and between portable and mobile units to perform operations 1856 related to the improvement of traffic flow, traffic safety, and other 1857 intelligent transportation service applications in a variety of 1858 environments. DSRCS systems may also transmit status and 1859 instructional messages related to the units involve. [Ref. 47 CFR 1860 90.7 - Definitions] 1861 OBU (On-Board Unit): a term defined outside the IETF. An On-Board 1862 Unit is a DSRCS transceiver that is normally mounted in or on a 1863 vehicle, or which in some instances may be a portable unit. An OBU 1864 can be operational while a vehicle or person is either mobile or 1865 stationary. The OBUs receive and contend for time to transmit on one 1866 or more radio frequency (RF) channels. Except where specifically 1867 excluded, OBU operation is permitted wherever vehicle operation or 1868 human passage is permitted. The OBUs mounted in vehicles are 1869 licensed by rule under part 95 of the respective chapter and 1870 communicate with Roadside Units (RSUs) and other OBUs. Portable OBUs 1871 are also licensed by rule under part 95 of the respective chapter. 1872 OBU operations in the Unlicensed National Information Infrastructure 1873 (UNII) Bands follow the rules in those bands. - [CFR 90.7 - 1874 Definitions]. 1876 RSU (Road-Side Unit): a term defined outside of IETF. A Roadside 1877 Unit is a DSRC transceiver that is mounted along a road or pedestrian 1878 passageway. An RSU may also be mounted on a vehicle or is hand 1879 carried, but it may only operate when the vehicle or hand- carried 1880 unit is stationary. Furthermore, an RSU operating under the 1881 respectgive part is restricted to the location where it is licensed 1882 to operate. However, portable or hand-held RSUs are permitted to 1883 operate where they do not interfere with a site-licensed operation. 1884 A RSU broadcasts data to OBUs or exchanges data with OBUs in its 1885 communications zone. An RSU also provides channel assignments and 1886 operating instructions to OBUs in its communications zone, when 1887 required. - [CFR 90.7 - Definitions]. 1889 Appendix J. Neighbor Discovery (ND) Potential Issues in Wireless Links 1891 IPv6 Neighbor Discovery (IPv6 ND) [RFC4861][RFC4862] was designed for 1892 point-to-point and transit links such as Ethernet, with the 1893 expectation of a cheap and reliable support for multicast from the 1894 lower layer. Section 3.2 of RFC 4861 indicates that the operation on 1895 Shared Media and on non-broadcast multi-access (NBMA) networks 1896 require additional support, e.g., for Address Resolution (AR) and 1897 duplicate address detection (DAD), which depend on multicast. An 1898 infrastructureless radio network such as OCB shares properties with 1899 both Shared Media and NBMA networks, and then adds its own 1900 complexity, e.g., from movement and interference that allow only 1901 transient and non-transitive reachability between any set of peers. 1903 The uniqueness of an address within a scoped domain is a key pillar 1904 of IPv6 and the base for unicast IP communication. RFC 4861 details 1905 the DAD method to avoid that an address is duplicated. For a link 1906 local address, the scope is the link, whereas for a Globally 1907 Reachable address the scope is much larger. The underlying 1908 assumption for DAD to operate correctly is that the node that owns an 1909 IPv6 address can reach any other node within the scope at the time it 1910 claims its address, which is done by sending a NS multicast message, 1911 and can hear any future claim for that address by another party 1912 within the scope for the duration of the address ownership. 1914 In the case of OCB, there is a potentially a need to define a scope 1915 that is compatible with DAD, and that cannot be the set of nodes that 1916 a transmitter can reach at a particular time, because that set varies 1917 all the time and does not meet the DAD requirements for a link local 1918 address that could possibly be used anytime, anywhere. The generic 1919 expectation of a reliable multicast is not ensured, and the operation 1920 of DAD and AR (Address Resolution) as specificed by RFC 4861 cannot 1921 be guaranteed. Moreoever, multicast transmissions that rely on 1922 broadcast are not only unreliable but are also often detrimental to 1923 unicast traffic (see [draft-ietf-mboned-ieee802-mcast-problems]). 1925 Early experience indicates that it should be possible to exchange 1926 IPv6 packets over OCB while relying on IPv6 ND alone for DAD and AR 1927 (Address Resolution) in good conditions. However, this does not 1928 apply if TBD TBD TBD. In the absence of a correct DAD operation, a 1929 node that relies only on IPv6 ND for AR and DAD over OCB should 1930 ensure that the addresses that it uses are unique by means others 1931 than DAD. It must be noted that deriving an IPv6 address from a 1932 globally unique MAC address has this property but may yield privacy 1933 issues. 1935 RFC 8505 provides a more recent approach to IPv6 ND and in particular 1936 DAD. RFC 8505 is designed to fit wireless and otherwise constrained 1937 networks whereby multicast and/or continuous access to the medium may 1938 not be guaranteed. RFC 8505 Section 5.6 "Link-Local Addresses and 1939 Registration" indicates that the scope of uniqueness for a link local 1940 address is restricted to a pair of nodes that use it to communicate, 1941 and provides a method to assert the uniqueness and resolve the link- 1942 Layer address using a unicast exchange. 1944 RFC 8505 also enables a router (acting as a 6LR) to own a prefix and 1945 act as a registrar (acting as a 6LBR) for addresses within the 1946 associated subnet. A peer host (acting as a 6LN) registers an 1947 address derived from that prefix and can use it for the lifetime of 1948 the registration. The prefix is advertised as not onlink, which 1949 means that the 6LN uses the 6LR to relay its packets within the 1950 subnet, and participation to the subnet is constrained to the time of 1951 reachability to the 6LR. Note that RSU that provides internet 1952 connectivity MAY announce a default router preference [RFC 4191], 1953 whereas a car that does not provide that connectivity MUST NOT do so. 1954 This operation presents similarities with that of an access point, 1955 but at Layer-3. This is why RFC 8505 well-suited for wireless in 1956 general. 1958 Support of RFC 8505 is may be implemented on OCB. OCB nodes that 1959 support RFC 8505 would support the 6LN operation in order to act as a 1960 host, and may support the 6LR and 6LBR operations in order to act as 1961 a router and in particular own a prefix that can be used by RFC 1962 8505-compliant hosts for address autoconfiguration and registration. 1964 Authors' Addresses 1966 Nabil Benamar 1967 Moulay Ismail University 1968 Morocco 1970 Phone: +212670832236 1971 Email: n.benamar@est.umi.ac.ma 1973 Jerome Haerri 1974 Eurecom 1975 Sophia-Antipolis 06904 1976 France 1978 Phone: +33493008134 1979 Email: Jerome.Haerri@eurecom.fr 1981 Jong-Hyouk Lee 1982 Sangmyung University 1983 31, Sangmyeongdae-gil, Dongnam-gu 1984 Cheonan 31066 1985 Republic of Korea 1987 Email: jonghyouk@smu.ac.kr 1989 Thierry Ernst 1990 YoGoKo 1991 France 1993 Email: thierry.ernst@yogoko.fr