idnits 2.17.1 draft-ietf-ipwave-ipv6-over-80211ocb-30.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 exact meaning of the all-uppercase expression 'MAY NOT' is not defined in RFC 2119. If it is intended as a requirements expression, it should be rewritten using one of the combinations defined in RFC 2119; otherwise it should not be all-uppercase. == 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: A subnet is formed by the external 802.11-OCB interfaces of vehicles that are in close range (not by their in-vehicle interfaces). This subnet MUST use at least the link-local prefix fe80::/10 and the interfaces MUST be assigned IPv6 addresses of type link-local. This subnet MAY NOT have any other prefix than the link-local prefix. -- The document date (September 24, 2018) is 2040 days in the past. Is this intentional? -- Found something which looks like a code comment -- if you have code sections in the document, please surround them with '' and '' lines. Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 2818 (Obsoleted by RFC 9110) ** Downref: Normative reference to an Informational RFC: RFC 3753 ** Downref: Normative reference to an Informational RFC: RFC 5889 ** Obsolete normative reference: RFC 7042 (Obsoleted by RFC 9542) ** Downref: Normative reference to an Informational RFC: RFC 7721 Summary: 5 errors (**), 0 flaws (~~), 2 warnings (==), 3 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: March 28, 2019 Moulay Ismail University 6 J. Haerri 7 Eurecom 8 J. Lee 9 Sangmyung University 10 T. Ernst 11 YoGoKo 12 September 24, 2018 14 Transmission of IPv6 Packets over IEEE 802.11 Networks operating in mode 15 Outside the Context of a Basic Service Set (IPv6-over-80211-OCB) 16 draft-ietf-ipwave-ipv6-over-80211ocb-30 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 March 28, 2019. 47 Copyright Notice 49 Copyright (c) 2018 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (https://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with respect 57 to this document. Code Components extracted from this document must 58 include Simplified BSD License text as described in Section 4.e of 59 the Trust Legal Provisions and are provided without warranty as 60 described in the Simplified BSD License. 62 Table of Contents 64 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 65 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 66 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 4 67 4. IPv6 over 802.11-OCB . . . . . . . . . . . . . . . . . . . . 5 68 4.1. Pseudonym Handling . . . . . . . . . . . . . . . . . . . 5 69 4.2. Maximum Transmission Unit (MTU) . . . . . . . . . . . . . 5 70 4.3. Frame Format . . . . . . . . . . . . . . . . . . . . . . 5 71 4.3.1. Ethernet Adaptation Layer . . . . . . . . . . . . . . 5 72 4.4. Link-Local Addresses . . . . . . . . . . . . . . . . . . 7 73 4.5. Address Mapping . . . . . . . . . . . . . . . . . . . . . 7 74 4.5.1. Address Mapping -- Unicast . . . . . . . . . . . . . 7 75 4.5.2. Address Mapping -- Multicast . . . . . . . . . . . . 7 76 4.6. Stateless Autoconfiguration . . . . . . . . . . . . . . . 7 77 4.7. Subnet Structure . . . . . . . . . . . . . . . . . . . . 9 78 5. Security Considerations . . . . . . . . . . . . . . . . . . . 10 79 5.1. Privacy Considerations . . . . . . . . . . . . . . . . . 10 80 5.2. MAC Address and Interface ID Generation . . . . . . . . . 11 81 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 82 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 12 83 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 84 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 85 9.1. Normative References . . . . . . . . . . . . . . . . . . 13 86 9.2. Informative References . . . . . . . . . . . . . . . . . 15 87 Appendix A. ChangeLog . . . . . . . . . . . . . . . . . . . . . 17 88 Appendix B. 802.11p . . . . . . . . . . . . . . . . . . . . . . 26 89 Appendix C. Aspects introduced by the OCB mode to 802.11 . . . . 26 90 Appendix D. Changes Needed on a software driver 802.11a to 91 become a 802.11-OCB driver . . . 30 92 Appendix E. EtherType Protocol Discrimination (EPD) . . . . . . 31 93 Appendix F. Design Considerations . . . . . . . . . . . . . . . 32 94 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode . . . . 32 95 Appendix H. Examples of Packet Formats . . . . . . . . . . . . . 33 96 H.1. Capture in Monitor Mode . . . . . . . . . . . . . . . . . 34 97 H.2. Capture in Normal Mode . . . . . . . . . . . . . . . . . 36 98 Appendix I. Extra Terminology . . . . . . . . . . . . . . . . . 38 99 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 39 101 1. Introduction 103 This document describes the transmission of IPv6 packets on IEEE Std 104 802.11-OCB networks [IEEE-802.11-2016] (a.k.a "802.11p" see 105 Appendix B, Appendix C and Appendix D). This involves the layering 106 of IPv6 networking on top of the IEEE 802.11 MAC layer, with an LLC 107 layer. Compared to running IPv6 over the Ethernet MAC layer, there 108 is no modification expected to IEEE Std 802.11 MAC and Logical Link 109 sublayers: IPv6 works fine directly over 802.11-OCB too, with an LLC 110 layer. 112 The IPv6 network layer operates on 802.11-OCB in the same manner as 113 operating on Ethernet, but there are two kinds of exceptions: 115 o Exceptions due to different operation of IPv6 network layer on 116 802.11 than on Ethernet. To satisfy these exceptions, this 117 document describes an Ethernet Adaptation Layer between Ethernet 118 headers and 802.11 headers. The Ethernet Adaptation Layer is 119 described Section 4.3.1. The operation of IP on Ethernet is 120 described in [RFC1042], [RFC2464] and 121 [I-D.hinden-6man-rfc2464bis]. 123 o Exceptions due to the OCB nature of 802.11-OCB compared to 802.11. 124 This has impacts on security, privacy, subnet structure and 125 handover behaviour. For security and privacy recommendations see 126 Section 5 and Section 4.6. The subnet structure is described in 127 Section 4.7. The handover behaviour on OCB links is not described 128 in this document. 130 The Security Considerations section describes security and privacy 131 aspects of 802.11-OCB. 133 In the published literature, many documents describe aspects and 134 problems related to running IPv6 over 802.11-OCB: 135 [I-D.ietf-ipwave-vehicular-networking-survey]. 137 2. Terminology 139 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 140 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 141 document are to be interpreted as described in RFC 2119 [RFC2119]. 143 IP-OBU (Internet Protocol On-Board Unit): an IP-OBU is a computer 144 situated in a vehicle such as an automobile, bicycle, or similar. It 145 has at least one IP interface that runs in mode OCB of 802.11, and 146 that has an "OBU" transceiver. See the definition of the term "OBU" 147 in section Appendix I. 149 IP-RSU (IP Road-Side Unit): an IP-RSU is situated along the road. It 150 has at least two distinct IP-enabled interfaces; the wireless PHY/MAC 151 layer of at least one of its IP-enabled interfaces is configured to 152 operate in 802.11-OCB mode. An IP-RSU communicates with the IP-OBU 153 in the vehicle over 802.11 wireless link operating in OCB mode. An 154 IP-RSU is similar to an Access Network Router (ANR) defined in 155 [RFC3753], and a Wireless Termination Point (WTP) defined in 156 [RFC5415]. 158 OCB (outside the context of a basic service set - BSS): A mode of 159 operation in which a STA is not a member of a BSS and does not 160 utilize IEEE Std 802.11 authentication, association, or data 161 confidentiality. 163 802.11-OCB: mode specified in IEEE Std 802.11-2016 when the MIB 164 attribute dot11OCBActivited is true. Note: compliance with standards 165 and regulations set in different countries when using the 5.9GHz 166 frequency band is required. 168 3. Communication Scenarios where IEEE 802.11-OCB Links are Used 170 The IEEE 802.11-OCB Networks are used for vehicular communications, 171 as 'Wireless Access in Vehicular Environments'. The IP communication 172 scenarios for these environments have been described in several 173 documents; in particular, we refer the reader to 174 [I-D.ietf-ipwave-vehicular-networking-survey], that lists some 175 scenarios and requirements for IP in Intelligent Transportation 176 Systems. 178 The link model is the following: STA --- 802.11-OCB --- STA. In 179 vehicular networks, STAs can be IP-RSUs and/or IP-OBUs. While 180 802.11-OCB is clearly specified, and the use of IPv6 over such link 181 is not radically new, the operating environment (vehicular networks) 182 brings in new perspectives. 184 The mechanisms for forming and terminating, discovering, peering and 185 mobility management for 802.11-OCB links are not described in this 186 document. 188 4. IPv6 over 802.11-OCB 190 4.1. Pseudonym Handling 192 Pseudonym. 194 4.2. Maximum Transmission Unit (MTU) 196 The default MTU for IP packets on 802.11-OCB MUST be 1500 octets. It 197 is the same value as IPv6 packets on Ethernet links, as specified in 198 [RFC2464]. This value of the MTU respects the recommendation that 199 every link on the Internet must have a minimum MTU of 1280 octets 200 (stated in [RFC8200], and the recommendations therein, especially 201 with respect to fragmentation). 203 4.3. Frame Format 205 IP packets MUST be transmitted over 802.11-OCB media as QoS Data 206 frames whose format is specified in IEEE Std 802.11. 208 The IPv6 packet transmitted on 802.11-OCB MUST be immediately 209 preceded by a Logical Link Control (LLC) header and an 802.11 header. 210 In the LLC header, and in accordance with the EtherType Protocol 211 Discrimination (EPD), the value of the Type field MUST be set to 212 0x86DD (IPv6). In the 802.11 header, the value of the Subtype sub- 213 field in the Frame Control field MUST be set to 8 (i.e. 'QoS Data'); 214 the value of the Traffic Identifier (TID) sub-field of the QoS 215 Control field of the 802.11 header MUST be set to binary 001 (i.e. 216 User Priority 'Background', QoS Access Category 'AC_BK'). 218 To simplify the Application Programming Interface (API) between the 219 operating system and the 802.11-OCB media, device drivers MAY 220 implement an Ethernet Adaptation Layer that translates Ethernet II 221 frames to the 802.11 format and vice versa. An Ethernet Adaptation 222 Layer is described in Section 4.3.1. 224 4.3.1. Ethernet Adaptation Layer 226 An 'adaptation' layer is inserted between a MAC layer and the 227 Networking layer. This is used to transform some parameters between 228 their form expected by the IP stack and the form provided by the MAC 229 layer. 231 An Ethernet Adaptation Layer makes an 802.11 MAC look to IP 232 Networking layer as a more traditional Ethernet layer. At reception, 233 this layer takes as input the IEEE 802.11 header and the Logical-Link 234 Layer Control Header and produces an Ethernet II Header. At sending, 235 the reverse operation is performed. 237 The operation of the Ethernet Adaptation Layer is depicted by the 238 double arrow in Figure 1. 240 +------------------+------------+-------------+---------+-----------+ 241 | 802.11 header | LLC Header | IPv6 Header | Payload |.11 Trailer| 242 +------------------+------------+-------------+---------+-----------+ 243 \ / \ / 244 --------------------------- -------- 245 \---------------------------------------------/ 246 ^ 247 | 248 802.11-to-Ethernet Adaptation Layer 249 | 250 v 251 +---------------------+-------------+---------+ 252 | Ethernet II Header | IPv6 Header | Payload | 253 +---------------------+-------------+---------+ 255 Figure 1: Operation of the Ethernet Adaptation Layer 257 The Receiver and Transmitter Address fields in the 802.11 header MUST 258 contain the same values as the Destination and the Source Address 259 fields in the Ethernet II Header, respectively. The value of the 260 Type field in the LLC Header MUST be the same as the value of the 261 Type field in the Ethernet II Header. That value MUST be set to 262 0x86DD (IPv6). 264 The ".11 Trailer" contains solely a 4-byte Frame Check Sequence. 266 The placement of IPv6 networking layer on Ethernet Adaptation Layer 267 is illustrated in Figure 2. 269 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 270 | IPv6 | 271 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 272 | Ethernet Adaptation Layer | 273 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 274 | 802.11 MAC | 275 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 276 | 802.11 PHY | 277 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 279 Figure 2: Ethernet Adaptation Layer stacked with other layers 281 (in the above figure, a 802.11 profile is represented; this is used 282 also for 802.11-OCB profile.) 284 4.4. Link-Local Addresses 286 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 287 MAY be assigned to an 802.11-OCB interface. Among these types of 288 addresses only the IPv6 link-local addresses MAY be formed using an 289 EUI-64 identifier. 291 If the IPv6 link-local address is formed using an EUI-64 identifier, 292 then the mechanism of forming that address is the same mechanism as 293 used to form an IPv6 link-local address on Ethernet links. This 294 mechanism is described in section 5 of [RFC2464]. 296 For privacy, the link-local address MAY be formed according to the 297 mechanisms described in Section 5.2. 299 4.5. Address Mapping 301 Unicast and multicast address mapping MUST follow the procedures 302 specified for Ethernet interfaces in sections 6 and 7 of [RFC2464]. 304 4.5.1. Address Mapping -- Unicast 306 The procedure for mapping IPv6 unicast addresses into Ethernet link- 307 layer addresses is described in [RFC4861]. 309 4.5.2. Address Mapping -- Multicast 311 The multicast address mapping is performed according to the method 312 specified in section 7 of [RFC2464]. The meaning of the value "3333" 313 mentioned in that section 7 of [RFC2464] is defined in section 2.3.1 314 of [RFC7042]. 316 Transmitting IPv6 packets to multicast destinations over 802.11 links 317 proved to have some performance issues 318 [I-D.perkins-intarea-multicast-ieee802]. These issues may be 319 exacerbated in OCB mode. Solutions for these problems should 320 consider the OCB mode of operation. 322 4.6. Stateless Autoconfiguration 324 There are several types of IPv6 addresses [RFC4291], [RFC4193], that 325 MAY be assigned to an 802.11-OCB interface. This section describes 326 the formation of Interface Identifiers for IPv6 addresses of type 327 'Global' or 'Unique Local'. For Interface Identifiers for IPv6 328 address of type 'Link-Local' see Section 4.4. 330 The Interface Identifier for an 802.11-OCB interface is formed using 331 the same rules as the Interface Identifier for an Ethernet interface; 332 the RECOMMENDED method for forming stable Interface Identifiers 333 (IIDs) is described in [RFC8064]. The method of forming IIDs 334 described in section 4 of [RFC2464] MAY be used during transition 335 time. 337 The bits in the Interface Identifier have no generic meaning and the 338 identifier should be treated as an opaque value. The bits 339 'Universal' and 'Group' in the identifier of an 802.11-OCB interface 340 are significant, as this is an IEEE link-layer address. The details 341 of this significance are described in [RFC7136]. If semantically 342 opaque Interface Identifiers are needed, a potential method for 343 generating semantically opaque Interface Identifiers with IPv6 344 Stateless Address Autoconfiguration is given in [RFC7217]. 346 Semantically opaque Interface Identifiers, instead of meaningful 347 Interface Identifiers derived from a valid and meaningful MAC address 348 ([RFC2464], section 4), MAY be needed in order to avoid certain 349 privacy risks. 351 A valid MAC address includes a unique identifier pointing to a 352 company together with its postal address, and a unique number within 353 that company MAC space (see the oui.txt file). The calculation 354 operation of the MAC address back from a given meaningful Interface 355 Identifier is straightforward ([RFC2464], section 4). The Interface 356 Identifier is part of an IPv6 address that is stored in IPv6 packets. 357 The IPv6 packets can be captured in the Internet easily. For these 358 reasons, an attacker may realize many attacks on privacy. One such 359 attack on 802.11-OCB is to capture, store and correlate Company ID 360 information of many cars in public areas (e.g. listen for Router 361 Advertisements, or other IPv6 application data packets, and record 362 the value of the source address in these packets). Further 363 correlation of this information with other data captured by other 364 means, or other visual information (car color, others) MAY constitute 365 privacy risks. 367 In order to avoid these risks, opaque Interface Identifiers MAY be 368 formed according to rules described in [RFC7217]. These opaque 369 Interface Identifiers are formed starting from identifiers different 370 than the MAC addresses, and from cryptographically strong material. 371 Thus, privacy sensitive information is absent from Interface IDs, and 372 it is impossible to calculate the initial value from which the 373 Interface ID was calculated. 375 Some applications that use IPv6 packets on 802.11-OCB links (among 376 other link types) may benefit from IPv6 addresses whose Interface 377 Identifiers don't change too often. It is RECOMMENDED to use the 378 mechanisms described in RFC 7217 to permit the use of Stable 379 Interface Identifiers that do not change within one subnet prefix. A 380 possible source for the Net-Iface Parameter is a virtual interface 381 name, or logical interface name, that is decided by a local 382 administrator. 384 The way Interface Identifiers are used MAY involve risks to privacy, 385 as described in Section 5.1. 387 4.7. Subnet Structure 389 A subnet is formed by the external 802.11-OCB interfaces of vehicles 390 that are in close range (not by their in-vehicle interfaces). This 391 subnet MUST use at least the link-local prefix fe80::/10 and the 392 interfaces MUST be assigned IPv6 addresses of type link-local. This 393 subnet MAY NOT have any other prefix than the link-local prefix. 395 The structure of this subnet is ephemeral, in that it is strongly 396 influenced by the mobility of vehicles: the 802.11 hidden node 397 effects appear; the 802.11 networks in OCB mode may be considered as 398 'ad-hoc' networks with an addressing model as described in [RFC5889]. 399 On another hand, the structure of the internal subnets in each car is 400 relatively stable. 402 As recommended in [RFC5889], when the timing requirements are very 403 strict (e.g. fast drive through IP-RSU coverage), no on-link subnet 404 prefix should be configured on an 802.11-OCB interface. In such 405 cases, the exclusive use of IPv6 link-local addresses is RECOMMENDED. 407 Additionally, even if the timing requirements are not very strict 408 (e.g. the moving subnet formed by two following vehicles is stable, a 409 fixed IP-RSU is absent), the subnet is disconnected from the Internet 410 (a default route is absent), and the addressing peers are equally 411 qualified (impossible to determine that some vehicle owns and 412 distributes addresses to others) the use of link-local addresses is 413 RECOMMENDED. 415 The Neighbor Discovery protocol (ND) [RFC4861] is used over 416 802.11-OCB links. The reliability of the ND protocol over 802.11-OCB 417 is the reliability of the delivery of ND multicast messages. This 418 reliability is the same as the reliability of delivery of ND 419 multicast messages over 802.11 links operated with a BSS ID. 421 The operation of the Mobile IPv6 protocol over 802.11-OCB links is 422 different than on other links. The Movement Detection operation 423 (section 11.5.1 of [RFC6275]) can not rely on Neighbor Unreachability 424 Detection operation of the Neighbor Discovery protocol, for the 425 reason mentioned in the previous paragraph. Also, the 802.11-OCB 426 link layer is not a lower layer that can provide an indication that a 427 link layer handover has occured. The operation of the Mobile IPv6 428 protocol over 802.11-OCB is not specified in this document. 430 5. Security Considerations 432 Any security mechanism at the IP layer or above that may be carried 433 out for the general case of IPv6 may also be carried out for IPv6 434 operating over 802.11-OCB. 436 The OCB operation is stripped off of all existing 802.11 link-layer 437 security mechanisms. There is no encryption applied below the 438 network layer running on 802.11-OCB. At application layer, the IEEE 439 1609.2 document [IEEE-1609.2] does provide security services for 440 certain applications to use; application-layer mechanisms are out-of- 441 scope of this document. On another hand, a security mechanism 442 provided at networking layer, such as IPsec [RFC4301], may provide 443 data security protection to a wider range of applications. 445 802.11-OCB does not provide any cryptographic protection, because it 446 operates outside the context of a BSS (no Association Request/ 447 Response, no Challenge messages). Any attacker can therefore just 448 sit in the near range of vehicles, sniff the network (just set the 449 interface card's frequency to the proper range) and perform attacks 450 without needing to physically break any wall. Such a link is less 451 protected than commonly used links (wired link or protected 802.11). 453 The potential attack vectors are: MAC address spoofing, IP address 454 and session hijacking, and privacy violation Section 5.1. 456 Within the IPsec Security Architecture [RFC4301], the IPsec AH and 457 ESP headers [RFC4302] and [RFC4303] respectively, its multicast 458 extensions [RFC5374], HTTPS [RFC2818] and SeND [RFC3971] protocols 459 can be used to protect communications. Further, the assistance of 460 proper Public Key Infrastructure (PKI) protocols [RFC4210] is 461 necessary to establish credentials. More IETF protocols are 462 available in the toolbox of the IP security protocol designer. 463 Certain ETSI protocols related to security protocols in Intelligent 464 Transportation Systems are described in [ETSI-sec-archi]. 466 5.1. Privacy Considerations 468 As with all Ethernet and 802.11 interface identifiers ([RFC7721]), 469 the identifier of an 802.11-OCB interface may involve privacy, MAC 470 address spoofing and IP address hijacking risks. A vehicle embarking 471 an IP-OBU whose egress interface is 802.11-OCB may expose itself to 472 eavesdropping and subsequent correlation of data; this may reveal 473 data considered private by the vehicle owner; there is a risk of 474 being tracked. In outdoors public environments, where vehicles 475 typically circulate, the privacy risks are more important than in 476 indoors settings. It is highly likely that attacker sniffers are 477 deployed along routes which listen for IEEE frames, including IP 478 packets, of vehicles passing by. For this reason, in the 802.11-OCB 479 deployments, there is a strong necessity to use protection tools such 480 as dynamically changing MAC addresses Section 5.2, semantically 481 opaque Interface Identifiers and stable Interface Identifiers 482 Section 4.6. This may help mitigate privacy risks to a certain 483 level. 485 5.2. MAC Address and Interface ID Generation 487 In 802.11-OCB networks, the MAC addresses MAY change during well 488 defined renumbering events. In the moment the MAC address is changed 489 on an 802.11-OCB interface all the Interface Identifiers of IPv6 490 addresses assigned to that interface MUST change. 492 The policy dictating when the MAC address is changed on the 493 802.11-OCB interface is to-be-determined. For more information on 494 the motivation of this policy please refer to the privacy discussion 495 in Appendix C. 497 A 'randomized' MAC address has the following characteristics: 499 o Bit "Local/Global" set to "locally admninistered". 501 o Bit "Unicast/Multicast" set to "Unicast". 503 o The 46 remaining bits are set to a random value, using a random 504 number generator that meets the requirements of [RFC4086]. 506 To meet the randomization requirements for the 46 remaining bits, a 507 hash function may be used. For example, the SHA256 hash function may 508 be used with input a 256 bit local secret, the 'nominal' MAC Address 509 of the interface, and a representation of the date and time of the 510 renumbering event. 512 A randomized Interface ID has the same characteristics of a 513 randomized MAC address, except the length in bits. A MAC address 514 SHOULD be of length 48 decimal. An Interface ID SHOULD be of length 515 64 decimal for all types of IPv6 addresses. In the particular case 516 of IPv6 link-local addresses, the length of the Interface ID MAY be 517 118 decimal. 519 6. IANA Considerations 521 No request to IANA. 523 7. Contributors 525 Christian Huitema, Tony Li. 527 Romain Kuntz contributed extensively about IPv6 handovers between 528 links running outside the context of a BSS (802.11-OCB links). 530 Tim Leinmueller contributed the idea of the use of IPv6 over 531 802.11-OCB for distribution of certificates. 533 Marios Makassikis, Jose Santa Lozano, Albin Severinson and Alexey 534 Voronov provided significant feedback on the experience of using IP 535 messages over 802.11-OCB in initial trials. 537 Michelle Wetterwald contributed extensively the MTU discussion, 538 offered the ETSI ITS perspective, and reviewed other parts of the 539 document. 541 8. Acknowledgements 543 The authors would like to thank Witold Klaudel, Ryuji Wakikawa, 544 Emmanuel Baccelli, John Kenney, John Moring, Francois Simon, Dan 545 Romascanu, Konstantin Khait, Ralph Droms, Richard 'Dick' Roy, Ray 546 Hunter, Tom Kurihara, Michal Sojka, Jan de Jongh, Suresh Krishnan, 547 Dino Farinacci, Vincent Park, Jaehoon Paul Jeong, Gloria Gwynne, 548 Hans-Joachim Fischer, Russ Housley, Rex Buddenberg, Erik Nordmark, 549 Bob Moskowitz, Andrew Dryden, Georg Mayer, Dorothy Stanley, Sandra 550 Cespedes, Mariano Falcitelli, Sri Gundavelli, Abdussalam Baryun, 551 Margaret Cullen, Erik Kline, Carlos Jesus Bernardos Cano, Ronald in 552 't Velt, Katrin Sjoberg, Roland Bless, Tijink Jasja, Kevin Smith, 553 Brian Carpenter, Julian Reschke, Mikael Abrahamsson and William 554 Whyte. Their valuable comments clarified particular issues and 555 generally helped to improve the document. 557 Pierre Pfister, Rostislav Lisovy, and others, wrote 802.11-OCB 558 drivers for linux and described how. 560 For the multicast discussion, the authors would like to thank Owen 561 DeLong, Joe Touch, Jen Linkova, Erik Kline, Brian Haberman and 562 participants to discussions in network working groups. 564 The authors would like to thank participants to the Birds-of- 565 a-Feather "Intelligent Transportation Systems" meetings held at IETF 566 in 2016. 568 Human Rights Protocol Considerations review by Amelia Andersdotter. 570 9. References 572 9.1. Normative References 574 [RFC1042] Postel, J. and J. Reynolds, "Standard for the transmission 575 of IP datagrams over IEEE 802 networks", STD 43, RFC 1042, 576 DOI 10.17487/RFC1042, February 1988, 577 . 579 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 580 Requirement Levels", BCP 14, RFC 2119, 581 DOI 10.17487/RFC2119, March 1997, 582 . 584 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 585 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 586 . 588 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 589 DOI 10.17487/RFC2818, May 2000, 590 . 592 [RFC3753] Manner, J., Ed. and M. Kojo, Ed., "Mobility Related 593 Terminology", RFC 3753, DOI 10.17487/RFC3753, June 2004, 594 . 596 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 597 "SEcure Neighbor Discovery (SEND)", RFC 3971, 598 DOI 10.17487/RFC3971, March 2005, 599 . 601 [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, 602 "Randomness Requirements for Security", BCP 106, RFC 4086, 603 DOI 10.17487/RFC4086, June 2005, 604 . 606 [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast 607 Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005, 608 . 610 [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, 611 "Internet X.509 Public Key Infrastructure Certificate 612 Management Protocol (CMP)", RFC 4210, 613 DOI 10.17487/RFC4210, September 2005, 614 . 616 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 617 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 618 2006, . 620 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 621 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 622 December 2005, . 624 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 625 DOI 10.17487/RFC4302, December 2005, 626 . 628 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 629 RFC 4303, DOI 10.17487/RFC4303, December 2005, 630 . 632 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 633 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 634 DOI 10.17487/RFC4861, September 2007, 635 . 637 [RFC5374] Weis, B., Gross, G., and D. Ignjatic, "Multicast 638 Extensions to the Security Architecture for the Internet 639 Protocol", RFC 5374, DOI 10.17487/RFC5374, November 2008, 640 . 642 [RFC5415] Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley, 643 Ed., "Control And Provisioning of Wireless Access Points 644 (CAPWAP) Protocol Specification", RFC 5415, 645 DOI 10.17487/RFC5415, March 2009, 646 . 648 [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing 649 Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889, 650 September 2010, . 652 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 653 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 654 2011, . 656 [RFC7042] Eastlake 3rd, D. and J. Abley, "IANA Considerations and 657 IETF Protocol and Documentation Usage for IEEE 802 658 Parameters", BCP 141, RFC 7042, DOI 10.17487/RFC7042, 659 October 2013, . 661 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 662 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 663 February 2014, . 665 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 666 Interface Identifiers with IPv6 Stateless Address 667 Autoconfiguration (SLAAC)", RFC 7217, 668 DOI 10.17487/RFC7217, April 2014, 669 . 671 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 672 Considerations for IPv6 Address Generation Mechanisms", 673 RFC 7721, DOI 10.17487/RFC7721, March 2016, 674 . 676 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 677 "Recommendation on Stable IPv6 Interface Identifiers", 678 RFC 8064, DOI 10.17487/RFC8064, February 2017, 679 . 681 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 682 (IPv6) Specification", STD 86, RFC 8200, 683 DOI 10.17487/RFC8200, July 2017, 684 . 686 9.2. Informative References 688 [ETSI-sec-archi] 689 "ETSI TS 102 940 V1.2.1 (2016-11), ETSI Technical 690 Specification, Intelligent Transport Systems (ITS); 691 Security; ITS communications security architecture and 692 security management, November 2016. Downloaded on 693 September 9th, 2017, freely available from ETSI website at 694 URL http://www.etsi.org/deliver/ 695 etsi_ts/102900_102999/102940/01.02.01_60/ 696 ts_102940v010201p.pdf". 698 [I-D.hinden-6man-rfc2464bis] 699 Crawford, M. and R. Hinden, "Transmission of IPv6 Packets 700 over Ethernet Networks", draft-hinden-6man-rfc2464bis-02 701 (work in progress), March 2017. 703 [I-D.ietf-ipwave-vehicular-networking-survey] 704 Jeong, J., Cespedes, S., Benamar, N., Haerri, J., and M. 705 Wetterwald, "Survey on IP-based Vehicular Networking for 706 Intelligent Transportation Systems", draft-ietf-ipwave- 707 vehicular-networking-survey-00 (work in progress), July 708 2017. 710 [I-D.perkins-intarea-multicast-ieee802] 711 Perkins, C., Stanley, D., Kumari, W., and J. Zuniga, 712 "Multicast Considerations over IEEE 802 Wireless Media", 713 draft-perkins-intarea-multicast-ieee802-03 (work in 714 progress), July 2017. 716 [IEEE-1609.2] 717 "IEEE SA - 1609.2-2016 - IEEE Standard for Wireless Access 718 in Vehicular Environments (WAVE) -- Security Services for 719 Applications and Management Messages. Example URL 720 http://ieeexplore.ieee.org/document/7426684/ accessed on 721 August 17th, 2017.". 723 [IEEE-1609.3] 724 "IEEE SA - 1609.3-2016 - IEEE Standard for Wireless Access 725 in Vehicular Environments (WAVE) -- Networking Services. 726 Example URL http://ieeexplore.ieee.org/document/7458115/ 727 accessed on August 17th, 2017.". 729 [IEEE-1609.4] 730 "IEEE SA - 1609.4-2016 - IEEE Standard for Wireless Access 731 in Vehicular Environments (WAVE) -- Multi-Channel 732 Operation. Example URL 733 http://ieeexplore.ieee.org/document/7435228/ accessed on 734 August 17th, 2017.". 736 [IEEE-802.11-2016] 737 "IEEE Standard 802.11-2016 - IEEE Standard for Information 738 Technology - Telecommunications and information exchange 739 between systems Local and metropolitan area networks - 740 Specific requirements - Part 11: Wireless LAN Medium 741 Access Control (MAC) and Physical Layer (PHY) 742 Specifications. Status - Active Standard. Description 743 retrieved freely on September 12th, 2017, at URL 744 https://standards.ieee.org/findstds/ 745 standard/802.11-2016.html". 747 [IEEE-802.11p-2010] 748 "IEEE Std 802.11p (TM)-2010, IEEE Standard for Information 749 Technology - Telecommunications and information exchange 750 between systems - Local and metropolitan area networks - 751 Specific requirements, Part 11: Wireless LAN Medium Access 752 Control (MAC) and Physical Layer (PHY) Specifications, 753 Amendment 6: Wireless Access in Vehicular Environments; 754 document freely available at URL 755 http://standards.ieee.org/getieee802/ 756 download/802.11p-2010.pdf retrieved on September 20th, 757 2013.". 759 Appendix A. ChangeLog 761 The changes are listed in reverse chronological order, most recent 762 changes appearing at the top of the list. 764 -30: a clarification on the reliability of ND over OCB and over 765 802.11. 767 -29: 769 o 771 -28: 773 o Created a new section 'Pseudonym Handling'. 775 o removed the 'Vehicle ID' appendix. 777 o improved the address generation from random MAC address. 779 o shortened Term IP-RSU definition. 781 o removed refs to two detail Clauses in IEEE documents, kept just 782 these latter. 784 -27: part 1 of addressing Human Rights review from IRTF. Removed 785 appendices F.2 and F.3. Shortened definition of IP-RSU. Removed 786 reference to 1609.4. A few other small changes, see diff. 788 -26: moved text from SLAAC section and from Design Considerations 789 appendix about privacy into a new Privacy Condiderations subsection 790 of the Security section; reformulated the SLAAC and IID sections to 791 stress only LLs can use EUI-64; removed the "GeoIP" wireshark 792 explanation; reformulated SLAAC and LL sections; added brief mention 793 of need of use LLs; clarified text about MAC address changes; dropped 794 pseudonym discussion; changed title of section describing examples of 795 packet formats. 797 -25: added a reference to 'IEEE Management Information Base', instead 798 of just 'Management Information Base'; added ref to further 799 appendices in the introductory phrases; improved text for IID 800 formation for SLAAC, inserting recommendation for RFC8064 before 801 RFC2464. 803 From draft-ietf-ipwave-ipv6-over-80211ocb-23 to draft-ietf-ipwave- 804 ipv6-over-80211ocb-24 805 o Nit: wrote "IPWAVE Working Group" on the front page, instead of 806 "Network Working Group". 808 o Addressed the comments on 6MAN: replaced a sentence about ND 809 problem with "is used over 802.11-OCB". 811 From draft-ietf-ipwave-ipv6-over-80211ocb-22 to draft-ietf-ipwave- 812 ipv6-over-80211ocb-23 814 o No content modifications, but check the entire draft chain on 815 IPv6-only: xml2rfc, submission on tools.ietf.org and datatracker. 817 From draft-ietf-ipwave-ipv6-over-80211ocb-21 to draft-ietf-ipwave- 818 ipv6-over-80211ocb-22 820 o Corrected typo, use dash in "802.11-OCB" instead of space. 822 o Improved the Frame Format section: MUST use QoSData, specify the 823 values within; clarified the Ethernet Adaptation Layer text. 825 From draft-ietf-ipwave-ipv6-over-80211ocb-20 to draft-ietf-ipwave- 826 ipv6-over-80211ocb-21 828 o Corrected a few nits and added names in Acknowledgments section. 830 o Removed unused reference to old Internet Draft tsvwg about QoS. 832 From draft-ietf-ipwave-ipv6-over-80211ocb-19 to draft-ietf-ipwave- 833 ipv6-over-80211ocb-20 835 o Reduced the definition of term "802.11-OCB". 837 o Left out of this specification which 802.11 header to use to 838 transmit IP packets in OCB mode (QoS Data header, Data header, or 839 any other). 841 o Added 'MUST' use an Ethernet Adaptation Layer, instead of 'is 842 using' an Ethernet Adaptation Layer. 844 From draft-ietf-ipwave-ipv6-over-80211ocb-18 to draft-ietf-ipwave- 845 ipv6-over-80211ocb-19 847 o Removed the text about fragmentation. 849 o Removed the mentioning of WSMP and GeoNetworking. 851 o Removed the explanation of the binary representation of the 852 EtherType. 854 o Rendered normative the paragraph about unicast and multicast 855 address mapping. 857 o Removed paragraph about addressing model, subnet structure and 858 easiness of using LLs. 860 o Clarified the Type/Subtype field in the 802.11 Header. 862 o Used RECOMMENDED instead of recommended, for the stable interface 863 identifiers. 865 From draft-ietf-ipwave-ipv6-over-80211ocb-17 to draft-ietf-ipwave- 866 ipv6-over-80211ocb-18 868 o Improved the MTU and fragmentation paragraph. 870 From draft-ietf-ipwave-ipv6-over-80211ocb-16 to draft-ietf-ipwave- 871 ipv6-over-80211ocb-17 873 o Susbtituted "MUST be increased" to "is increased" in the MTU 874 section, about fragmentation. 876 From draft-ietf-ipwave-ipv6-over-80211ocb-15 to draft-ietf-ipwave- 877 ipv6-over-80211ocb-16 879 o Removed the definition of the 'WiFi' term and its occurences. 880 Clarified a phrase that used it in Appendix C "Aspects introduced 881 by the OCB mode to 802.11". 883 o Added more normative words: MUST be 0x86DD, MUST fragment if size 884 larger than MTU, Sequence number in 802.11 Data header MUST be 885 increased. 887 From draft-ietf-ipwave-ipv6-over-80211ocb-14 to draft-ietf-ipwave- 888 ipv6-over-80211ocb-15 890 o Added normative term MUST in two places in section "Ethernet 891 Adaptation Layer". 893 From draft-ietf-ipwave-ipv6-over-80211ocb-13 to draft-ietf-ipwave- 894 ipv6-over-80211ocb-14 896 o Created a new Appendix titled "Extra Terminology" that contains 897 terms DSRC, DSRCS, OBU, RSU as defined outside IETF. Some of them 898 are used in the main Terminology section. 900 o Added two paragraphs explaining that ND and Mobile IPv6 have 901 problems working over 802.11-OCB, yet their adaptations is not 902 specified in this document. 904 From draft-ietf-ipwave-ipv6-over-80211ocb-12 to draft-ietf-ipwave- 905 ipv6-over-80211ocb-13 907 o Substituted "IP-OBU" for "OBRU", and "IP-RSU" for "RSRU" 908 throughout and improved OBU-related definitions in the Terminology 909 section. 911 From draft-ietf-ipwave-ipv6-over-80211ocb-11 to draft-ietf-ipwave- 912 ipv6-over-80211ocb-12 914 o Improved the appendix about "MAC Address Generation" by expressing 915 the technique to be an optional suggestion, not a mandatory 916 mechanism. 918 From draft-ietf-ipwave-ipv6-over-80211ocb-10 to draft-ietf-ipwave- 919 ipv6-over-80211ocb-11 921 o Shortened the paragraph on forming/terminating 802.11-OCB links. 923 o Moved the draft tsvwg-ieee-802-11 to Informative References. 925 From draft-ietf-ipwave-ipv6-over-80211ocb-09 to draft-ietf-ipwave- 926 ipv6-over-80211ocb-10 928 o Removed text requesting a new Group ID for multicast for OCB. 930 o Added a clarification of the meaning of value "3333" in the 931 section Address Mapping -- Multicast. 933 o Added note clarifying that in Europe the regional authority is not 934 ETSI, but "ECC/CEPT based on ENs from ETSI". 936 o Added note stating that the manner in which two STAtions set their 937 communication channel is not described in this document. 939 o Added a time qualifier to state that the "each node is represented 940 uniquely at a certain point in time." 942 o Removed text "This section may need to be moved" (the "Reliability 943 Requirements" section). This section stays there at this time. 945 o In the term definition "802.11-OCB" added a note stating that "any 946 implementation should comply with standards and regulations set in 947 the different countries for using that frequency band." 949 o In the RSU term definition, added a sentence explaining the 950 difference between RSU and RSRU: in terms of number of interfaces 951 and IP forwarding. 953 o Replaced "with at least two IP interfaces" with "with at least two 954 real or virtual IP interfaces". 956 o Added a term in the Terminology for "OBU". However the definition 957 is left empty, as this term is defined outside IETF. 959 o Added a clarification that it is an OBU or an OBRU in this phrase 960 "A vehicle embarking an OBU or an OBRU". 962 o Checked the entire document for a consistent use of terms OBU and 963 OBRU. 965 o Added note saying that "'p' is a letter identifying the 966 Ammendment". 968 o Substituted lower case for capitals SHALL or MUST in the 969 Appendices. 971 o Added reference to RFC7042, helpful in the 3333 explanation. 972 Removed reference to individual submission draft-petrescu-its- 973 scenario-reqs and added reference to draft-ietf-ipwave-vehicular- 974 networking-survey. 976 o Added figure captions, figure numbers, and references to figure 977 numbers instead of 'below'. Replaced "section Section" with 978 "section" throughout. 980 o Minor typographical errors. 982 From draft-ietf-ipwave-ipv6-over-80211ocb-08 to draft-ietf-ipwave- 983 ipv6-over-80211ocb-09 985 o Significantly shortened the Address Mapping sections, by text 986 copied from RFC2464, and rather referring to it. 988 o Moved the EPD description to an Appendix on its own. 990 o Shortened the Introduction and the Abstract. 992 o Moved the tutorial section of OCB mode introduced to .11, into an 993 appendix. 995 o Removed the statement that suggests that for routing purposes a 996 prefix exchange mechanism could be needed. 998 o Removed refs to RFC3963, RFC4429 and RFC6775; these are about ND, 999 MIP/NEMO and oDAD; they were referred in the handover discussion 1000 section, which is out. 1002 o Updated a reference from individual submission to now a WG item in 1003 IPWAVE: the survey document. 1005 o Added term definition for WiFi. 1007 o Updated the authorship and expanded the Contributors section. 1009 o Corrected typographical errors. 1011 From draft-ietf-ipwave-ipv6-over-80211ocb-07 to draft-ietf-ipwave- 1012 ipv6-over-80211ocb-08 1014 o Removed the per-channel IPv6 prohibition text. 1016 o Corrected typographical errors. 1018 From draft-ietf-ipwave-ipv6-over-80211ocb-06 to draft-ietf-ipwave- 1019 ipv6-over-80211ocb-07 1021 o Added new terms: OBRU and RSRU ('R' for Router). Refined the 1022 existing terms RSU and OBU, which are no longer used throughout 1023 the document. 1025 o Improved definition of term "802.11-OCB". 1027 o Clarified that OCB does not "strip" security, but that the 1028 operation in OCB mode is "stripped off of all .11 security". 1030 o Clarified that theoretical OCB bandwidth speed is 54mbits, but 1031 that a commonly observed bandwidth in IP-over-OCB is 12mbit/s. 1033 o Corrected typographical errors, and improved some phrasing. 1035 From draft-ietf-ipwave-ipv6-over-80211ocb-05 to draft-ietf-ipwave- 1036 ipv6-over-80211ocb-06 1038 o Updated references of 802.11-OCB document from -2012 to the IEEE 1039 802.11-2016. 1041 o In the LL address section, and in SLAAC section, added references 1042 to 7217 opaque IIDs and 8064 stable IIDs. 1044 From draft-ietf-ipwave-ipv6-over-80211ocb-04 to draft-ietf-ipwave- 1045 ipv6-over-80211ocb-05 1046 o Lengthened the title and cleanded the abstract. 1048 o Added text suggesting LLs may be easy to use on OCB, rather than 1049 GUAs based on received prefix. 1051 o Added the risks of spoofing and hijacking. 1053 o Removed the text speculation on adoption of the TSA message. 1055 o Clarified that the ND protocol is used. 1057 o Clarified what it means "No association needed". 1059 o Added some text about how two STAs discover each other. 1061 o Added mention of external (OCB) and internal network (stable), in 1062 the subnet structure section. 1064 o Added phrase explaining that both .11 Data and .11 QoS Data 1065 headers are currently being used, and may be used in the future. 1067 o Moved the packet capture example into an Appendix Implementation 1068 Status. 1070 o Suggested moving the reliability requirements appendix out into 1071 another document. 1073 o Added a IANA Consiserations section, with content, requesting for 1074 a new multicast group "all OCB interfaces". 1076 o Added new OBU term, improved the RSU term definition, removed the 1077 ETTC term, replaced more occurences of 802.11p, 802.11-OCB with 1078 802.11-OCB. 1080 o References: 1082 * Added an informational reference to ETSI's IPv6-over- 1083 GeoNetworking. 1085 * Added more references to IETF and ETSI security protocols. 1087 * Updated some references from I-D to RFC, and from old RFC to 1088 new RFC numbers. 1090 * Added reference to multicast extensions to IPsec architecture 1091 RFC. 1093 * Added a reference to 2464-bis. 1095 * Removed FCC informative references, because not used. 1097 o Updated the affiliation of one author. 1099 o Reformulation of some phrases for better readability, and 1100 correction of typographical errors. 1102 From draft-ietf-ipwave-ipv6-over-80211ocb-03 to draft-ietf-ipwave- 1103 ipv6-over-80211ocb-04 1105 o Removed a few informative references pointing to Dx draft IEEE 1106 1609 documents. 1108 o Removed outdated informative references to ETSI documents. 1110 o Added citations to IEEE 1609.2, .3 and .4-2016. 1112 o Minor textual issues. 1114 From draft-ietf-ipwave-ipv6-over-80211ocb-02 to draft-ietf-ipwave- 1115 ipv6-over-80211ocb-03 1117 o Keep the previous text on multiple addresses, so remove talk about 1118 MIP6, NEMOv6 and MCoA. 1120 o Clarified that a 'Beacon' is an IEEE 802.11 frame Beacon. 1122 o Clarified the figure showing Infrastructure mode and OCB mode side 1123 by side. 1125 o Added a reference to the IP Security Architecture RFC. 1127 o Detailed the IPv6-per-channel prohibition paragraph which reflects 1128 the discussion at the last IETF IPWAVE WG meeting. 1130 o Added section "Address Mapping -- Unicast". 1132 o Added the ".11 Trailer" to pictures of 802.11 frames. 1134 o Added text about SNAP carrying the Ethertype. 1136 o New RSU definition allowing for it be both a Router and not 1137 necessarily a Router some times. 1139 o Minor textual issues. 1141 From draft-ietf-ipwave-ipv6-over-80211ocb-01 to draft-ietf-ipwave- 1142 ipv6-over-80211ocb-02 1143 o Replaced almost all occurences of 802.11p with 802.11-OCB, leaving 1144 only when explanation of evolution was necessary. 1146 o Shortened by removing parameter details from a paragraph in the 1147 Introduction. 1149 o Moved a reference from Normative to Informative. 1151 o Added text in intro clarifying there is no handover spec at IEEE, 1152 and that 1609.2 does provide security services. 1154 o Named the contents the fields of the EthernetII header (including 1155 the Ethertype bitstring). 1157 o Improved relationship between two paragraphs describing the 1158 increase of the Sequence Number in 802.11 header upon IP 1159 fragmentation. 1161 o Added brief clarification of "tracking". 1163 From draft-ietf-ipwave-ipv6-over-80211ocb-00 to draft-ietf-ipwave- 1164 ipv6-over-80211ocb-01 1166 o Introduced message exchange diagram illustrating differences 1167 between 802.11 and 802.11 in OCB mode. 1169 o Introduced an appendix listing for information the set of 802.11 1170 messages that may be transmitted in OCB mode. 1172 o Removed appendix sections "Privacy Requirements", "Authentication 1173 Requirements" and "Security Certificate Generation". 1175 o Removed appendix section "Non IP Communications". 1177 o Introductory phrase in the Security Considerations section. 1179 o Improved the definition of "OCB". 1181 o Introduced theoretical stacked layers about IPv6 and IEEE layers 1182 including EPD. 1184 o Removed the appendix describing the details of prohibiting IPv6 on 1185 certain channels relevant to 802.11-OCB. 1187 o Added a brief reference in the privacy text about a precise clause 1188 in IEEE 1609.3 and .4. 1190 o Clarified the definition of a Road Side Unit. 1192 o Removed the discussion about security of WSA (because is non-IP). 1194 o Removed mentioning of the GeoNetworking discussion. 1196 o Moved references to scientific articles to a separate 'overview' 1197 draft, and referred to it. 1199 Appendix B. 802.11p 1201 The term "802.11p" is an earlier definition. The behaviour of 1202 "802.11p" networks is rolled in the document IEEE Std 802.11-2016. 1203 In that document the term 802.11p disappears. Instead, each 802.11p 1204 feature is conditioned by the IEEE Management Information Base (MIB) 1205 attribute "OCBActivated" [IEEE-802.11-2016]. Whenever OCBActivated 1206 is set to true the IEEE Std 802.11-OCB state is activated. For 1207 example, an 802.11 STAtion operating outside the context of a basic 1208 service set has the OCBActivated flag set. Such a station, when it 1209 has the flag set, uses a BSS identifier equal to ff:ff:ff:ff:ff:ff. 1211 Appendix C. Aspects introduced by the OCB mode to 802.11 1213 In the IEEE 802.11-OCB mode, all nodes in the wireless range can 1214 directly communicate with each other without involving authentication 1215 or association procedures. At link layer, it is necessary to set the 1216 same channel number (or frequency) on two stations that need to 1217 communicate with each other. The manner in which stations set their 1218 channel number is not specified in this document. Stations STA1 and 1219 STA2 can exchange IP packets if they are set on the same channel. At 1220 IP layer, they then discover each other by using the IPv6 Neighbor 1221 Discovery protocol. 1223 Briefly, the IEEE 802.11-OCB mode has the following properties: 1225 o The use by each node of a 'wildcard' BSSID (i.e., each bit of the 1226 BSSID is set to 1) 1228 o No IEEE 802.11 Beacon frames are transmitted 1230 o No authentication is required in order to be able to communicate 1232 o No association is needed in order to be able to communicate 1234 o No encryption is provided in order to be able to communicate 1236 o Flag dot11OCBActivated is set to true 1238 All the nodes in the radio communication range (IP-OBU and IP-RSU) 1239 receive all the messages transmitted (IP-OBU and IP-RSU) within the 1240 radio communications range. The eventual conflict(s) are resolved by 1241 the MAC CDMA function. 1243 The message exchange diagram in Figure 3 illustrates a comparison 1244 between traditional 802.11 and 802.11 in OCB mode. The 'Data' 1245 messages can be IP packets such as HTTP or others. Other 802.11 1246 management and control frames (non IP) may be transmitted, as 1247 specified in the 802.11 standard. For information, the names of 1248 these messages as currently specified by the 802.11 standard are 1249 listed in Appendix G. 1251 STA AP STA1 STA2 1252 | | | | 1253 |<------ Beacon -------| |<------ Data -------->| 1254 | | | | 1255 |---- Probe Req. ----->| |<------ Data -------->| 1256 |<--- Probe Res. ------| | | 1257 | | |<------ Data -------->| 1258 |---- Auth Req. ------>| | | 1259 |<--- Auth Res. -------| |<------ Data -------->| 1260 | | | | 1261 |---- Asso Req. ------>| |<------ Data -------->| 1262 |<--- Asso Res. -------| | | 1263 | | |<------ Data -------->| 1264 |<------ Data -------->| | | 1265 |<------ Data -------->| |<------ Data -------->| 1267 (i) 802.11 Infrastructure mode (ii) 802.11-OCB mode 1269 Figure 3: Difference between messages exchanged on 802.11 (left) and 1270 802.11-OCB (right) 1272 The interface 802.11-OCB was specified in IEEE Std 802.11p (TM) -2010 1273 [IEEE-802.11p-2010] as an amendment to IEEE Std 802.11 (TM) -2007, 1274 titled "Amendment 6: Wireless Access in Vehicular Environments". 1275 Since then, this amendment has been integrated in IEEE 802.11(TM) 1276 -2012 and -2016 [IEEE-802.11-2016]. 1278 In document 802.11-2016, anything qualified specifically as 1279 "OCBActivated", or "outside the context of a basic service" set to be 1280 true, then it is actually referring to OCB aspects introduced to 1281 802.11. 1283 In order to delineate the aspects introduced by 802.11-OCB to 802.11, 1284 we refer to the earlier [IEEE-802.11p-2010]. The amendment is 1285 concerned with vehicular communications, where the wireless link is 1286 similar to that of Wireless LAN (using a PHY layer specified by 1287 802.11a/b/g/n), but which needs to cope with the high mobility factor 1288 inherent in scenarios of communications between moving vehicles, and 1289 between vehicles and fixed infrastructure deployed along roads. 1290 While 'p' is a letter identifying the Ammendment, just like 'a, b, g' 1291 and 'n' are, 'p' is concerned more with MAC modifications, and a 1292 little with PHY modifications; the others are mainly about PHY 1293 modifications. It is possible in practice to combine a 'p' MAC with 1294 an 'a' PHY by operating outside the context of a BSS with OFDM at 1295 5.4GHz and 5.9GHz. 1297 The 802.11-OCB links are specified to be compatible as much as 1298 possible with the behaviour of 802.11a/b/g/n and future generation 1299 IEEE WLAN links. From the IP perspective, an 802.11-OCB MAC layer 1300 offers practically the same interface to IP as the 802.11a/b/g/n and 1301 802.3. A packet sent by an IP-OBU may be received by one or multiple 1302 IP-RSUs. The link-layer resolution is performed by using the IPv6 1303 Neighbor Discovery protocol. 1305 To support this similarity statement (IPv6 is layered on top of LLC 1306 on top of 802.11-OCB, in the same way that IPv6 is layered on top of 1307 LLC on top of 802.11a/b/g/n (for WLAN) or layered on top of LLC on 1308 top of 802.3 (for Ethernet)) it is useful to analyze the differences 1309 between 802.11-OCB and 802.11 specifications. During this analysis, 1310 we note that whereas 802.11-OCB lists relatively complex and numerous 1311 changes to the MAC layer (and very little to the PHY layer), there 1312 are only a few characteristics which may be important for an 1313 implementation transmitting IPv6 packets on 802.11-OCB links. 1315 The most important 802.11-OCB point which influences the IPv6 1316 functioning is the OCB characteristic; an additional, less direct 1317 influence, is the maximum bandwidth afforded by the PHY modulation/ 1318 demodulation methods and channel access specified by 802.11-OCB. The 1319 maximum bandwidth theoretically possible in 802.11-OCB is 54 Mbit/s 1320 (when using, for example, the following parameters: 20 MHz channel; 1321 modulation 64-QAM; coding rate R is 3/4); in practice of IP-over- 1322 802.11-OCB a commonly observed figure is 12Mbit/s; this bandwidth 1323 allows the operation of a wide range of protocols relying on IPv6. 1325 o Operation Outside the Context of a BSS (OCB): the (earlier 1326 802.11p) 802.11-OCB links are operated without a Basic Service Set 1327 (BSS). This means that the frames IEEE 802.11 Beacon, Association 1328 Request/Response, Authentication Request/Response, and similar, 1329 are not used. The used identifier of BSS (BSSID) has a 1330 hexadecimal value always 0xffffffffffff (48 '1' bits, represented 1331 as MAC address ff:ff:ff:ff:ff:ff, or otherwise the 'wildcard' 1332 BSSID), as opposed to an arbitrary BSSID value set by 1333 administrator (e.g. 'My-Home-AccessPoint'). The OCB operation - 1334 namely the lack of beacon-based scanning and lack of 1335 authentication - should be taken into account when the Mobile IPv6 1336 protocol [RFC6275] and the protocols for IP layer security 1337 [RFC4301] are used. The way these protocols adapt to OCB is not 1338 described in this document. 1340 o Timing Advertisement: is a new message defined in 802.11-OCB, 1341 which does not exist in 802.11a/b/g/n. This message is used by 1342 stations to inform other stations about the value of time. It is 1343 similar to the time as delivered by a GNSS system (Galileo, GPS, 1344 ...) or by a cellular system. This message is optional for 1345 implementation. 1347 o Frequency range: this is a characteristic of the PHY layer, with 1348 almost no impact on the interface between MAC and IP. However, it 1349 is worth considering that the frequency range is regulated by a 1350 regional authority (ARCEP, ECC/CEPT based on ENs from ETSI, FCC, 1351 etc.); as part of the regulation process, specific applications 1352 are associated with specific frequency ranges. In the case of 1353 802.11-OCB, the regulator associates a set of frequency ranges, or 1354 slots within a band, to the use of applications of vehicular 1355 communications, in a band known as "5.9GHz". The 5.9GHz band is 1356 different from the 2.4GHz and 5GHz bands used by Wireless LAN. 1357 However, as with Wireless LAN, the operation of 802.11-OCB in 1358 "5.9GHz" bands is exempt from owning a license in EU (in US the 1359 5.9GHz is a licensed band of spectrum; for the fixed 1360 infrastructure an explicit FCC authorization is required; for an 1361 on-board device a 'licensed-by-rule' concept applies: rule 1362 certification conformity is required.) Technical conditions are 1363 different than those of the bands "2.4GHz" or "5GHz". The allowed 1364 power levels, and implicitly the maximum allowed distance between 1365 vehicles, is of 33dBm for 802.11-OCB (in Europe), compared to 20 1366 dBm for Wireless LAN 802.11a/b/g/n; this leads to a maximum 1367 distance of approximately 1km, compared to approximately 50m. 1368 Additionally, specific conditions related to congestion avoidance, 1369 jamming avoidance, and radar detection are imposed on the use of 1370 DSRC (in US) and on the use of frequencies for Intelligent 1371 Transportation Systems (in EU), compared to Wireless LAN 1372 (802.11a/b/g/n). 1374 o 'Half-rate' encoding: as the frequency range, this parameter is 1375 related to PHY, and thus has not much impact on the interface 1376 between the IP layer and the MAC layer. 1378 o In vehicular communications using 802.11-OCB links, there are 1379 strong privacy requirements with respect to addressing. While the 1380 802.11-OCB standard does not specify anything in particular with 1381 respect to MAC addresses, in these settings there exists a strong 1382 need for dynamic change of these addresses (as opposed to the non- 1383 vehicular settings - real wall protection - where fixed MAC 1384 addresses do not currently pose some privacy risks). This is 1385 further described in Section 5. A relevant function is described 1386 in documents IEEE 1609.3-2016 [IEEE-1609.3] and IEEE 1609.4-2016 1387 [IEEE-1609.4]. 1389 Appendix D. Changes Needed on a software driver 802.11a to become a 1390 802.11-OCB driver 1392 The 802.11p amendment modifies both the 802.11 stack's physical and 1393 MAC layers but all the induced modifications can be quite easily 1394 obtained by modifying an existing 802.11a ad-hoc stack. 1396 Conditions for a 802.11a hardware to be 802.11-OCB compliant: 1398 o The PHY entity shall be an orthogonal frequency division 1399 multiplexing (OFDM) system. It must support the frequency bands 1400 on which the regulator recommends the use of ITS communications, 1401 for example using IEEE 802.11-OCB layer, in France: 5875MHz to 1402 5925MHz. 1404 o The OFDM system must provide a "half-clocked" operation using 10 1405 MHz channel spacings. 1407 o The chip transmit spectrum mask must be compliant to the "Transmit 1408 spectrum mask" from the IEEE 802.11p amendment (but experimental 1409 environments tolerate otherwise). 1411 o The chip should be able to transmit up to 44.8 dBm when used by 1412 the US government in the United States, and up to 33 dBm in 1413 Europe; other regional conditions apply. 1415 Changes needed on the network stack in OCB mode: 1417 o Physical layer: 1419 * The chip must use the Orthogonal Frequency Multiple Access 1420 (OFDM) encoding mode. 1422 * The chip must be set in half-mode rate mode (the internal clock 1423 frequency is divided by two). 1425 * The chip must use dedicated channels and should allow the use 1426 of higher emission powers. This may require modifications to 1427 the local computer file that describes regulatory domains 1428 rules, if used by the kernel to enforce local specific 1429 restrictions. Such modifications to the local computer file 1430 must respect the location-specific regulatory rules. 1432 MAC layer: 1434 * All management frames (beacons, join, leave, and others) 1435 emission and reception must be disabled except for frames of 1436 subtype Action and Timing Advertisement (defined below). 1438 * No encryption key or method must be used. 1440 * Packet emission and reception must be performed as in ad-hoc 1441 mode, using the wildcard BSSID (ff:ff:ff:ff:ff:ff). 1443 * The functions related to joining a BSS (Association Request/ 1444 Response) and for authentication (Authentication Request/Reply, 1445 Challenge) are not called. 1447 * The beacon interval is always set to 0 (zero). 1449 * Timing Advertisement frames, defined in the amendment, should 1450 be supported. The upper layer should be able to trigger such 1451 frames emission and to retrieve information contained in 1452 received Timing Advertisements. 1454 Appendix E. EtherType Protocol Discrimination (EPD) 1456 A more theoretical and detailed view of layer stacking, and 1457 interfaces between the IP layer and 802.11-OCB layers, is illustrated 1458 in Figure 4. The IP layer operates on top of the EtherType Protocol 1459 Discrimination (EPD); this Discrimination layer is described in IEEE 1460 Std 802.3-2012; the interface between IPv6 and EPD is the LLC_SAP 1461 (Link Layer Control Service Access Point). 1463 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1464 | IPv6 | 1465 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ 1466 { LLC_SAP } 802.11-OCB 1467 +-+-+-+-+-+-{ }+-+-+-+-+-+-+-+ Boundary 1468 | EPD | | | 1469 | | MLME | | 1470 +-+-+-{ MAC_SAP }+-+-+-| MLME_SAP | 1471 | MAC Sublayer | | | 802.11-OCB 1472 | and ch. coord. | | SME | Services 1473 +-+-+-{ PHY_SAP }+-+-+-+-+-+-+-| | 1474 | | PLME | | 1475 | PHY Layer | PLME_SAP | 1476 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1478 Figure 4: EtherType Protocol Discrimination 1480 Appendix F. Design Considerations 1482 The networks defined by 802.11-OCB are in many ways similar to other 1483 networks of the 802.11 family. In theory, the encapsulation of IPv6 1484 over 802.11-OCB could be very similar to the operation of IPv6 over 1485 other networks of the 802.11 family. However, the high mobility, 1486 strong link asymmetry and very short connection makes the 802.11-OCB 1487 link significantly different from other 802.11 networks. Also, the 1488 automotive applications have specific requirements for reliability, 1489 security and privacy, which further add to the particularity of the 1490 802.11-OCB link. 1492 Appendix G. IEEE 802.11 Messages Transmitted in OCB mode 1494 For information, at the time of writing, this is the list of IEEE 1495 802.11 messages that may be transmitted in OCB mode, i.e. when 1496 dot11OCBActivated is true in a STA: 1498 o The STA may send management frames of subtype Action and, if the 1499 STA maintains a TSF Timer, subtype Timing Advertisement; 1501 o The STA may send control frames, except those of subtype PS-Poll, 1502 CF-End, and CF-End plus CFAck; 1504 o The STA may send data frames of subtype Data, Null, QoS Data, and 1505 QoS Null. 1507 Appendix H. Examples of Packet Formats 1509 This section describes an example of an IPv6 Packet captured over a 1510 IEEE 802.11-OCB link. 1512 By way of example we show that there is no modification in the 1513 headers when transmitted over 802.11-OCB networks - they are 1514 transmitted like any other 802.11 and Ethernet packets. 1516 We describe an experiment of capturing an IPv6 packet on an 1517 802.11-OCB link. In topology depicted in Figure 5, the packet is an 1518 IPv6 Router Advertisement. This packet is emitted by a Router on its 1519 802.11-OCB interface. The packet is captured on the Host, using a 1520 network protocol analyzer (e.g. Wireshark); the capture is performed 1521 in two different modes: direct mode and 'monitor' mode. The topology 1522 used during the capture is depicted below. 1524 The packet is captured on the Host. The Host is an IP-OBU containing 1525 an 802.11 interface in format PCI express (an ITRI product). The 1526 kernel runs the ath5k software driver with modifications for OCB 1527 mode. The capture tool is Wireshark. The file format for save and 1528 analyze is 'pcap'. The packet is generated by the Router. The 1529 Router is an IP-RSU (ITRI product). 1531 +--------+ +-------+ 1532 | | 802.11-OCB Link | | 1533 ---| Router |--------------------------------| Host | 1534 | | | | 1535 +--------+ +-------+ 1537 Figure 5: Topology for capturing IP packets on 802.11-OCB 1539 During several capture operations running from a few moments to 1540 several hours, no message relevant to the BSSID contexts were 1541 captured (no Association Request/Response, Authentication Req/Resp, 1542 Beacon). This shows that the operation of 802.11-OCB is outside the 1543 context of a BSSID. 1545 Overall, the captured message is identical with a capture of an IPv6 1546 packet emitted on a 802.11b interface. The contents are precisely 1547 similar. 1549 H.1. Capture in Monitor Mode 1551 The IPv6 RA packet captured in monitor mode is illustrated below. 1552 The radio tap header provides more flexibility for reporting the 1553 characteristics of frames. The Radiotap Header is prepended by this 1554 particular stack and operating system on the Host machine to the RA 1555 packet received from the network (the Radiotap Header is not present 1556 on the air). The implementation-dependent Radiotap Header is useful 1557 for piggybacking PHY information from the chip's registers as data in 1558 a packet understandable by userland applications using Socket 1559 interfaces (the PHY interface can be, for example: power levels, data 1560 rate, ratio of signal to noise). 1562 The packet present on the air is formed by IEEE 802.11 Data Header, 1563 Logical Link Control Header, IPv6 Base Header and ICMPv6 Header. 1565 Radiotap Header v0 1566 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1567 |Header Revision| Header Pad | Header length | 1568 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1569 | Present flags | 1570 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1571 | Data Rate | Pad | 1572 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1574 IEEE 802.11 Data Header 1575 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1576 | Type/Subtype and Frame Ctrl | Duration | 1577 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1578 | Receiver Address... 1579 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1580 ... Receiver Address | Transmitter Address... 1581 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1582 ... Transmitter Address | 1583 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1584 | BSS Id... 1585 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1586 ... BSS Id | Frag Number and Seq Number | 1587 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1589 Logical-Link Control Header 1590 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1591 | DSAP |I| SSAP |C| Control field | Org. code... 1592 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1593 ... Organizational Code | Type | 1594 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1595 IPv6 Base Header 1596 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1597 |Version| Traffic Class | Flow Label | 1598 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1599 | Payload Length | Next Header | Hop Limit | 1600 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1601 | | 1602 + + 1603 | | 1604 + Source Address + 1605 | | 1606 + + 1607 | | 1608 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1609 | | 1610 + + 1611 | | 1612 + Destination Address + 1613 | | 1614 + + 1615 | | 1616 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1618 Router Advertisement 1619 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1620 | Type | Code | Checksum | 1621 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1622 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1623 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1624 | Reachable Time | 1625 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1626 | Retrans Timer | 1627 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1628 | Options ... 1629 +-+-+-+-+-+-+-+-+-+-+-+- 1631 The value of the Data Rate field in the Radiotap header is set to 6 1632 Mb/s. This indicates the rate at which this RA was received. 1634 The value of the Transmitter address in the IEEE 802.11 Data Header 1635 is set to a 48bit value. The value of the destination address is 1636 33:33:00:00:00:1 (all-nodes multicast address). The value of the BSS 1637 Id field is ff:ff:ff:ff:ff:ff, which is recognized by the network 1638 protocol analyzer as being "broadcast". The Fragment number and 1639 sequence number fields are together set to 0x90C6. 1641 The value of the Organization Code field in the Logical-Link Control 1642 Header is set to 0x0, recognized as "Encapsulated Ethernet". The 1643 value of the Type field is 0x86DD (hexadecimal 86DD, or otherwise 1644 #86DD), recognized as "IPv6". 1646 A Router Advertisement is periodically sent by the router to 1647 multicast group address ff02::1. It is an icmp packet type 134. The 1648 IPv6 Neighbor Discovery's Router Advertisement message contains an 1649 8-bit field reserved for single-bit flags, as described in [RFC4861]. 1651 The IPv6 header contains the link local address of the router 1652 (source) configured via EUI-64 algorithm, and destination address set 1653 to ff02::1. 1655 The Ethernet Type field in the logical-link control header is set to 1656 0x86dd which indicates that the frame transports an IPv6 packet. In 1657 the IEEE 802.11 data, the destination address is 33:33:00:00:00:01 1658 which is the corresponding multicast MAC address. The BSS id is a 1659 broadcast address of ff:ff:ff:ff:ff:ff. Due to the short link 1660 duration between vehicles and the roadside infrastructure, there is 1661 no need in IEEE 802.11-OCB to wait for the completion of association 1662 and authentication procedures before exchanging data. IEEE 1663 802.11-OCB enabled nodes use the wildcard BSSID (a value of all 1s) 1664 and may start communicating as soon as they arrive on the 1665 communication channel. 1667 H.2. Capture in Normal Mode 1669 The same IPv6 Router Advertisement packet described above (monitor 1670 mode) is captured on the Host, in the Normal mode, and depicted 1671 below. 1673 Ethernet II Header 1674 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1675 | Destination... 1676 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1677 ...Destination | Source... 1678 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1679 ...Source | 1680 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1681 | Type | 1682 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1684 IPv6 Base Header 1685 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1686 |Version| Traffic Class | Flow Label | 1687 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1688 | Payload Length | Next Header | Hop Limit | 1689 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1690 | | 1691 + + 1692 | | 1693 + Source Address + 1694 | | 1695 + + 1696 | | 1697 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1698 | | 1699 + + 1700 | | 1701 + Destination Address + 1702 | | 1703 + + 1704 | | 1705 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1707 Router Advertisement 1708 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1709 | Type | Code | Checksum | 1710 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1711 | Cur Hop Limit |M|O| Reserved | Router Lifetime | 1712 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1713 | Reachable Time | 1714 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1715 | Retrans Timer | 1716 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1717 | Options ... 1718 +-+-+-+-+-+-+-+-+-+-+-+- 1720 One notices that the Radiotap Header, the IEEE 802.11 Data Header and 1721 the Logical-Link Control Headers are not present. On the other hand, 1722 a new header named Ethernet II Header is present. 1724 The Destination and Source addresses in the Ethernet II header 1725 contain the same values as the fields Receiver Address and 1726 Transmitter Address present in the IEEE 802.11 Data Header in the 1727 "monitor" mode capture. 1729 The value of the Type field in the Ethernet II header is 0x86DD 1730 (recognized as "IPv6"); this value is the same value as the value of 1731 the field Type in the Logical-Link Control Header in the "monitor" 1732 mode capture. 1734 The knowledgeable experimenter will no doubt notice the similarity of 1735 this Ethernet II Header with a capture in normal mode on a pure 1736 Ethernet cable interface. 1738 An Adaptation layer is inserted on top of a pure IEEE 802.11 MAC 1739 layer, in order to adapt packets, before delivering the payload data 1740 to the applications. It adapts 802.11 LLC/MAC headers to Ethernet II 1741 headers. In further detail, this adaptation consists in the 1742 elimination of the Radiotap, 802.11 and LLC headers, and in the 1743 insertion of the Ethernet II header. In this way, IPv6 runs straight 1744 over LLC over the 802.11-OCB MAC layer; this is further confirmed by 1745 the use of the unique Type 0x86DD. 1747 Appendix I. Extra Terminology 1749 The following terms are defined outside the IETF. They are used to 1750 define the main terms in the main terminology section Section 2. 1752 DSRC (Dedicated Short Range Communication): a term defined outside 1753 the IETF. The US Federal Communications Commission (FCC) Dedicated 1754 Short Range Communication (DSRC) is defined in the Code of Federal 1755 Regulations (CFR) 47, Parts 90 and 95. This Code is referred in the 1756 definitions below. At the time of the writing of this Internet 1757 Draft, the last update of this Code was dated October 1st, 2010. 1759 DSRCS (Dedicated Short-Range Communications Services): a term defined 1760 outside the IETF. The use of radio techniques to transfer data over 1761 short distances between roadside and mobile units, between mobile 1762 units, and between portable and mobile units to perform operations 1763 related to the improvement of traffic flow, traffic safety, and other 1764 intelligent transportation service applications in a variety of 1765 environments. DSRCS systems may also transmit status and 1766 instructional messages related to the units involve. [Ref. 47 CFR 1767 90.7 - Definitions] 1768 OBU (On-Board Unit): a term defined outside the IETF. An On-Board 1769 Unit is a DSRCS transceiver that is normally mounted in or on a 1770 vehicle, or which in some instances may be a portable unit. An OBU 1771 can be operational while a vehicle or person is either mobile or 1772 stationary. The OBUs receive and contend for time to transmit on one 1773 or more radio frequency (RF) channels. Except where specifically 1774 excluded, OBU operation is permitted wherever vehicle operation or 1775 human passage is permitted. The OBUs mounted in vehicles are 1776 licensed by rule under part 95 of the respective chapter and 1777 communicate with Roadside Units (RSUs) and other OBUs. Portable OBUs 1778 are also licensed by rule under part 95 of the respective chapter. 1779 OBU operations in the Unlicensed National Information Infrastructure 1780 (UNII) Bands follow the rules in those bands. - [CFR 90.7 - 1781 Definitions]. 1783 RSU (Road-Side Unit): a term defined outside of IETF. A Roadside 1784 Unit is a DSRC transceiver that is mounted along a road or pedestrian 1785 passageway. An RSU may also be mounted on a vehicle or is hand 1786 carried, but it may only operate when the vehicle or hand- carried 1787 unit is stationary. Furthermore, an RSU operating under the 1788 respectgive part is restricted to the location where it is licensed 1789 to operate. However, portable or hand-held RSUs are permitted to 1790 operate where they do not interfere with a site-licensed operation. 1791 A RSU broadcasts data to OBUs or exchanges data with OBUs in its 1792 communications zone. An RSU also provides channel assignments and 1793 operating instructions to OBUs in its communications zone, when 1794 required. - [CFR 90.7 - Definitions]. 1796 Authors' Addresses 1798 Alexandre Petrescu 1799 CEA, LIST 1800 CEA Saclay 1801 Gif-sur-Yvette , Ile-de-France 91190 1802 France 1804 Phone: +33169089223 1805 Email: Alexandre.Petrescu@cea.fr 1807 Nabil Benamar 1808 Moulay Ismail University 1809 Morocco 1811 Phone: +212670832236 1812 Email: n.benamar@est.umi.ac.ma 1813 Jerome Haerri 1814 Eurecom 1815 Sophia-Antipolis 06904 1816 France 1818 Phone: +33493008134 1819 Email: Jerome.Haerri@eurecom.fr 1821 Jong-Hyouk Lee 1822 Sangmyung University 1823 31, Sangmyeongdae-gil, Dongnam-gu 1824 Cheonan 31066 1825 Republic of Korea 1827 Email: jonghyouk@smu.ac.kr 1829 Thierry Ernst 1830 YoGoKo 1831 France 1833 Email: thierry.ernst@yogoko.fr