idnits 2.17.1 draft-ietf-6lo-nfc-05.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: NFC provides fragmentation and reassembly (FAR) for payloads from 128 bytes up to 2176 bytes as mentioned in Section 3.4. The MTU of a general IPv6 packet can fit into a single NFC link frame. Therefore, the FAR functionality as defined in RFC 4944, which specifies the fragmentation methods for IPv6 datagrams on top of IEEE 802.15.4, MAY NOT be required as the basis for IPv6 datagram FAR on top of NFC. The NFC link connection for IPv6 over NFC MUST be configured with an equivalent MIU size to fit the MTU of IPv6 Packet. If NFC devices support extension of the MTU, the MIUX value is 0x480 in order to fit the MTU (1280 bytes) of a IPv6 packet. -- The document date (October 11, 2016) is 2753 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- Looks like a reference, but probably isn't: 'RFC6282' on line 438 == Unused Reference: '12' is defined on line 694, but no explicit reference was found in the text -- Possible downref: Non-RFC (?) normative reference: ref. '3' ** Obsolete normative reference: RFC 3633 (ref. '8') (Obsoleted by RFC 8415) Summary: 1 error (**), 0 flaws (~~), 3 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 6Lo Working Group Y-H. Choi 3 Internet-Draft Y-G. Hong 4 Intended status: Standards Track ETRI 5 Expires: April 14, 2017 J-S. Youn 6 Dongeui Univ 7 D-K. Kim 8 KNU 9 J-H. Choi 10 Samsung Electronics Co., 11 October 11, 2016 13 Transmission of IPv6 Packets over Near Field Communication 14 draft-ietf-6lo-nfc-05 16 Abstract 18 Near field communication (NFC) is a set of standards for smartphones 19 and portable devices to establish radio communication with each other 20 by touching them together or bringing them into proximity, usually no 21 more than 10 cm. NFC standards cover communications protocols and 22 data exchange formats, and are based on existing radio-frequency 23 identification (RFID) standards including ISO/IEC 14443 and FeliCa. 24 The standards include ISO/IEC 18092 and those defined by the NFC 25 Forum. The NFC technology has been widely implemented and available 26 in mobile phones, laptop computers, and many other devices. This 27 document describes how IPv6 is transmitted over NFC using 6LowPAN 28 techniques. 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 http://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 April 14, 2017. 47 Copyright Notice 49 Copyright (c) 2016 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 (http://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. Conventions and Terminology . . . . . . . . . . . . . . . . . 3 66 3. Overview of Near Field Communication Technology . . . . . . . 4 67 3.1. Peer-to-peer Mode of NFC . . . . . . . . . . . . . . . . 4 68 3.2. Protocol Stacks of NFC . . . . . . . . . . . . . . . . . 4 69 3.3. NFC-enabled Device Addressing . . . . . . . . . . . . . . 6 70 3.4. NFC MAC PDU Size and MTU . . . . . . . . . . . . . . . . 6 71 4. Specification of IPv6 over NFC . . . . . . . . . . . . . . . 7 72 4.1. Protocol Stacks . . . . . . . . . . . . . . . . . . . . . 7 73 4.2. Link Model . . . . . . . . . . . . . . . . . . . . . . . 7 74 4.3. Stateless Address Autoconfiguration . . . . . . . . . . . 8 75 4.4. IPv6 Link Local Address . . . . . . . . . . . . . . . . . 9 76 4.5. Neighbor Discovery . . . . . . . . . . . . . . . . . . . 9 77 4.6. Dispatch Header . . . . . . . . . . . . . . . . . . . . . 9 78 4.7. Header Compression . . . . . . . . . . . . . . . . . . . 10 79 4.8. Fragmentation and Reassembly . . . . . . . . . . . . . . 11 80 4.9. Unicast Address Mapping . . . . . . . . . . . . . . . . . 11 81 4.10. Multicast Address Mapping . . . . . . . . . . . . . . . . 12 82 5. Internet Connectivity Scenarios . . . . . . . . . . . . . . . 12 83 5.1. NFC-enabled Device Connected to the Internet . . . . . . 12 84 5.2. Isolated NFC-enabled Device Network . . . . . . . . . . . 13 85 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 86 7. Security Considerations . . . . . . . . . . . . . . . . . . . 13 87 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14 88 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 89 9.1. Normative References . . . . . . . . . . . . . . . . . . 14 90 9.2. Informative References . . . . . . . . . . . . . . . . . 15 91 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 93 1. Introduction 95 NFC is a set of short-range wireless technologies, typically 96 requiring a distance of 10 cm or less. NFC operates at 13.56 MHz on 97 ISO/IEC 18000-3 air interface and at rates ranging from 106 kbit/s to 98 424 kbit/s. NFC always involves an initiator and a target; the 99 initiator actively generates an RF field that can power a passive 100 target. This enables NFC targets to take very simple form factors 101 such as tags, stickers, key fobs, or cards that do not require 102 batteries. NFC peer-to-peer communication is possible, provided both 103 devices are powered. NFC builds upon RFID systems by allowing two- 104 way communication between endpoints, where earlier systems such as 105 contactless smart cards were one-way only. It has been used in 106 devices such as mobile phones, running Android operating system, 107 named with a feature called "Android Beam". In addition, it is 108 expected for the other mobile phones, running the other operating 109 systems (e.g., iOS, etc.) to be equipped with NFC technology in the 110 near future. 112 Considering the potential for exponential growth in the number of 113 heterogeneous air interface technologies, NFC would be widely used as 114 one of the other air interface technologies, such as Bluetooth Low 115 Energy (BT-LE), Wi-Fi, and so on. Each of the heterogeneous air 116 interface technologies has its own characteristics, which cannot be 117 covered by the other technologies, so various kinds of air interface 118 technologies would co-exist together. Therefore, it is required for 119 them to communicate with each other. NFC also has the strongest 120 ability (e.g., secure communication distance of 10 cm) to prevent a 121 third party from attacking privacy. 123 When the number of devices and things having different air interface 124 technologies communicate with each other, IPv6 is an ideal internet 125 protocols owing to its large address space. Also, NFC would be one 126 of the endpoints using IPv6. Therefore, this document describes how 127 IPv6 is transmitted over NFC using 6LoWPAN techniques. 129 RFC4944 [1] specifies the transmission of IPv6 over IEEE 802.15.4. 130 The NFC link also has similar characteristics to that of IEEE 131 802.15.4. Many of the mechanisms defined in RFC 4944 [1] can be 132 applied to the transmission of IPv6 on NFC links. This document 133 specifies the details of IPv6 transmission over NFC links. 135 2. Conventions and Terminology 137 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 138 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 139 document are to be interpreted as described in [2]. 141 3. Overview of Near Field Communication Technology 143 NFC technology enables simple and safe two-way interactions between 144 electronic devices, allowing consumers to perform contactless 145 transactions, access digital content, and connect electronic devices 146 with a single touch. NFC complements many popular consumer level 147 wireless technologies, by utilizing the key elements in existing 148 standards for contactless card technology (ISO/IEC 14443 A&B and 149 JIS-X 6319-4). NFC can be compatible with existing contactless card 150 infrastructure and it enables a consumer to utilize one device across 151 different systems. 153 Extending the capability of contactless card technology, NFC also 154 enables devices to share information at a distance that is less than 155 10 cm with a maximum communication speed of 424 kbps. Users can 156 share business cards, make transactions, access information from a 157 smart poster or provide credentials for access control systems with a 158 simple touch. 160 NFC's bidirectional communication ability is ideal for establishing 161 connections with other technologies by the simplicity of touch. In 162 addition to the easy connection and quick transactions, simple data 163 sharing is also available. 165 3.1. Peer-to-peer Mode of NFC 167 NFC-enabled devices are unique in that they can support three modes 168 of operation: card emulation, peer-to-peer, and reader/writer. Peer- 169 to-peer mode enables two NFC-enabled devices to communicate with each 170 other to exchange information and share files, so that users of NFC- 171 enabled devices can quickly share contact information and other files 172 with a touch. Therefore, an NFC-enabled device can securely send 173 IPv6 packets to any corresponding node on the Internet when an NFC- 174 enabled gateway is linked to the Internet. 176 3.2. Protocol Stacks of NFC 178 IP can use the services provided by the Logical Link Control Protocol 179 (LLCP) in the NFC stack to provide reliable, two-way transport of 180 information between the peer devices. Figure 1 depicts the NFC P2P 181 protocol stack with IPv6 bindings to LLCP. 183 For data communication in IPv6 over NFC, an IPv6 packet SHALL be 184 passed down to LLCP of NFC and transported to an Information Field in 185 Protocol Data Unit (I PDU) of LLCP of the NFC-enabled peer device. 186 LLCP does not support fragmentation and reassembly. For IPv6 187 addressing or address configuration, LLCP SHALL provide related 188 information, such as link layer addresses, to its upper layer. The 189 LLCP to IPv6 protocol binding SHALL transfer the SSAP and DSAP value 190 to the IPv6 over NFC protocol. SSAP stands for Source Service Access 191 Point, which is a 6-bit value meaning a kind of Logical Link Control 192 (LLC) address, while DSAP means an LLC address of the destination 193 NFC-enabled device. 195 | | 196 | | Application Layer 197 | Upper Layer Protocols | Transport Layer 198 | | Network Layer 199 | | | 200 +----------------------------------------+ <------------------ 201 | IPv6-LLCP Binding | | 202 +----------------------------------------+ NFC 203 | | Logical Link 204 | Logical Link Control Protocol | Layer 205 | (LLCP) | | 206 +----------------------------------------+ <------------------ 207 | | | 208 | Activities | | 209 | Digital Protocol | NFC 210 | | Physical 211 +----------------------------------------+ Layer 212 | | | 213 | RF Analog | | 214 | | | 215 +----------------------------------------+ <------------------ 217 Figure 1: Protocol Stacks of NFC 219 The LLCP consists of Logical Link Control (LLC) and MAC Mapping. The 220 MAC Mapping integrates an existing RF protocol into the LLCP 221 architecture. The LLC contains three components, such as Link 222 Management, Connection-oriented Transport, and Connection-less 223 Transport. The Link Management component is responsible for 224 serializing all connection-oriented and connection-less LLC PDU 225 (Protocol Data Unit) exchanges and for aggregation and disaggregation 226 of small PDUs. This component also guarantees asynchronous balanced 227 mode communication and provides link status supervision by performing 228 the symmetry procedure. The Connection-oriented Transport component 229 is responsible for maintaining all connection-oriented data exchanges 230 including connection set-up and termination. The Connectionless 231 Transport component is responsible for handling unacknowledged data 232 exchanges. 234 3.3. NFC-enabled Device Addressing 236 According to NFCForum-TS-LLCP_1.3 [3], NFC-enabled devices have two 237 types of 6-bit addresses (i.e., SSAP and DSAP) to identify service 238 access points. The several service access points can be installed on 239 a NFC device. However, the SSAP and DSAP can be used as identifiers 240 for NFC link connections with the IPv6 over NFC adaptation layer. 241 Therefore, the SSAP can be used to generate an IPv6 interface 242 identifier. Address values between 00h and 0Fh of SSAP and DSAP are 243 reserved for identifying the well-known service access points, which 244 are defined in the NFC Forum Assigned Numbers Register. Address 245 values between 10h and 1Fh SHALL be assigned by the local LLC to 246 services registered by local service environment. In addition, 247 address values between 20h and 3Fh SHALL be assigned by the local LLC 248 as a result of an upper layer service request. Therefore, the 249 address values between 20h and 3Fh can be used for generating IPv6 250 interface identifiers. 252 3.4. NFC MAC PDU Size and MTU 254 As mentioned in Section 3.2, an IPv6 packet SHALL passed down to LLCP 255 of NFC and transported to an Unnumbered Information Protocol Data 256 Unit (UI PDU) and an Information Field in Protocol Data Unit (I PDU) 257 of LLCP of the NFC-enabled peer device. 259 The information field of an I PDU SHALL contain a single service data 260 unit. The maximum number of octets in the information field is 261 determined by the Maximum Information Unit (MIU) for the data link 262 connection. The default value of the MIU for I PDUs SHALL be 128 263 octets. The local and remote LLCs each establish and maintain 264 distinct MIU values for each data link connection endpoint. Also, an 265 LLC MAY announce a larger MIU for a data link connection by 266 transmitting an MIUX extension parameter within the information 267 field. If no MIUX parameter is transmitted, the default MIU value of 268 128 SHALL be used. Otherwise, the MTU size in NFC LLCP SHALL 269 calculate the MIU value as follows: 271 MIU = 128 + MIUX. 273 When the MIUX parameter is encoded as a TLV, the TLV Type field SHALL 274 be 0x02 and the TLV Length field SHALL be 0x02. The MIUX parameter 275 SHALL be encoded into the least significant 11 bits of the TLV Value 276 field. The unused bits in the TLV Value field SHALL be set to zero 277 by the sender and SHALL be ignored by the receiver. However, a 278 maximum value of the TLV Value field can be 0x7FF, and a maximum size 279 of the MTU in NFC LLCP is 2176 bytes. 281 4. Specification of IPv6 over NFC 283 NFC technology also has considerations and requirements owing to low 284 power consumption and allowed protocol overhead. 6LoWPAN standards 285 RFC 4944 [1], RFC 6775 [4], and RFC 6282 [5] provide useful 286 functionality for reducing overhead which can be applied to NFC. 287 This functionality consists of link-local IPv6 addresses and 288 stateless IPv6 address auto-configuration (see Section 4.3), Neighbor 289 Discovery (see Section 4.5) and header compression (see Section 4.7). 291 4.1. Protocol Stacks 293 Figure 2 illustrates IPv6 over NFC. Upper layer protocols can be 294 transport layer protocols (TCP and UDP), application layer protocols, 295 and others capable running on top of IPv6. 297 | | Transport & 298 | Upper Layer Protocols | Application Layer 299 +----------------------------------------+ <------------------ 300 | | | 301 | IPv6 | | 302 | | Network 303 +----------------------------------------+ Layer 304 | Adaptation Layer for IPv6 over NFC | | 305 +----------------------------------------+ <------------------ 306 | IPv6-LLCP Binding | 307 | Logical Link Control Protocol | NFC Link Layer 308 | (LLCP) | | 309 +----------------------------------------+ <------------------ 310 | | | 311 | Activities | NFC 312 | Digital Protocol | Physical Layer 313 | RF Analog | | 314 | | | 315 +----------------------------------------+ <------------------ 317 Figure 2: Protocol Stacks for IPv6 over NFC 319 The adaptation layer for IPv6 over NFC SHALL support neighbor 320 discovery, stateless address auto-configuration, header compression, 321 and fragmentation & reassembly. 323 4.2. Link Model 325 In the case of BT-LE, the Logical Link Control and Adaptation 326 Protocol (L2CAP) supports fragmentation and reassembly (FAR) 327 functionality; therefore, the adaptation layer for IPv6 over BT-LE 328 does not have to conduct the FAR procedure. The NFC LLCP, in 329 contrast, does not support the FAR functionality, so IPv6 over NFC 330 needs to consider the FAR functionality, defined in RFC 4944 [1]. 331 However, the MTU on an NFC link can be configured in a connection 332 procedure and extended enough to fit the MTU of IPv6 packet (see 333 Section 4.8). 335 The NFC link between two communicating devices is considered to be a 336 point-to-point link only. Unlike in BT-LE, an NFC link does not 337 support a star topology or mesh network topology but only direct 338 connections between two devices. Furthermore, the NFC link layer 339 does not support packet forwarding in link layer. Due to this 340 characteristics, 6LoWPAN functionalities, such as addressing and 341 auto-configuration, and header compression, need to be specialized 342 into IPv6 over NFC. 344 4.3. Stateless Address Autoconfiguration 346 An NFC-enabled device (i.e., 6LN) performs stateless address 347 autoconfiguration as per RFC 4862 [6]. A 64-bit Interface identifier 348 (IID) for an NFC interface is formed by utilizing the 6-bit NFC LLCP 349 address (see Section 3.3). In the viewpoint of address 350 configuration, such an IID SHOULD guarantee a stable IPv6 address 351 because each data link connection is uniquely identified by the pair 352 of DSAP and SSAP included in the header of each LLC PDU in NFC. 354 Following the guidance of RFC 7136 [10], interface identifiers of all 355 unicast addresses for NFC-enabled devices are 64 bits long and 356 constructed in a modified EUI-64 format as shown in Figure 3. 358 0 1 3 4 6 359 0 6 2 8 3 360 +----------------+----------------+----------------+-----------------+ 361 |000000u000000000|0000000011111111|11111110RRRRRRRR|RRRRRRRRRRRRRRRRR| 362 +----------------+----------------+----------------+-----------------+ 364 Figure 3: Formation of IID from NFC-enabled device address 366 The 'R' bits are random values which MAY be created by mechanisms 367 like hash function with the SSAP as an input value because the 6-bit 368 address of SSAP is easy and short to be targeted by attacks of third 369 party (e.g., address scanning). In addition, the "Universal/Local" 370 bit (i.e., the 'u' bit) of an NFC-enabled device address MUST be set 371 to 0 RFC 4291 [7]. 373 4.4. IPv6 Link Local Address 375 Only if the NFC-enabled device address is known to be a public 376 address, the "Universal/Local" bit be set to 1. The IPv6 link-local 377 address for an NFC-enabled device is formed by appending the IID, to 378 the prefix FE80::/64, as depicted in Figure 4. 380 0 0 0 1 381 0 1 6 2 382 0 0 4 7 383 +----------+------------------+----------------------------+ 384 |1111111010| zeros | Interface Identifier | 385 +----------+------------------+----------------------------+ 386 | | 387 | <---------------------- 128 bits ----------------------> | 388 | | 390 Figure 4: IPv6 link-local address in NFC 392 The tool for a 6LBR to obtain an IPv6 prefix for numbering the NFC 393 network is can be accomplished via DHCPv6 Prefix Delegation (RFC 3633 394 [8]). 396 4.5. Neighbor Discovery 398 Neighbor Discovery Optimization for 6LoWPANs (RFC 6775 [4]) describes 399 the neighbor discovery approach in several 6LoWPAN topologies, such 400 as mesh topology. NFC does not support a complicated mesh topology 401 but only a simple multi-hop network topology or directly connected 402 peer-to-peer network. Therefore, the following aspects of RFC 6775 403 are applicable to NFC: 405 1. In a case that an NFC-enabled device (6LN) is directly connected 406 to a 6LBR, an NFC 6LN MUST register its address with the 6LBR by 407 sending a Neighbor Solicitation (NS) message with the Address 408 Registration Option (ARO) and process the Neighbor Advertisement 409 (NA) accordingly. In addition, if DHCPv6 is used to assign an 410 address, Duplicate Address Detection (DAD) MAY not be required. 412 2. For sending Router Solicitations and processing Router 413 Advertisements the NFC 6LNs MUST follow Sections 5.3 and 5.4 of 414 RFC 6775. 416 4.6. Dispatch Header 418 All IPv6-over-NFC encapsulated datagrams are prefixed by an 419 encapsulation header stack consisting of a Dispatch value followed by 420 zero or more header fields. The only sequence currently defined for 421 IPv6-over-NFC is the LOWPAN_IPHC header followed by payload, as 422 depicted in Figure 5. 424 +---------------+---------------+--------------+ 425 | IPHC Dispatch | IPHC Header | Payload | 426 +---------------+---------------+--------------+ 428 Figure 5: A IPv6-over-NFC Encapsulated 6LOWPAN_IPHC Compressed IPv6 429 Datagram 431 The dispatch value may be treated as an unstructured namespace. Only 432 a single pattern is used to represent current IPv6-over-NFC 433 functionality. 435 +------------+--------------------+-----------+ 436 | Pattern | Header Type | Reference | 437 +------------+--------------------+-----------+ 438 | 01 1xxxxx | 6LOWPAN_IPHC | [RFC6282] | 439 +------------+--------------------+-----------+ 441 Figure 6: Dispatch Values 443 Other IANA-assigned 6LoWPAN Dispatch values do not apply to this 444 specification. 446 4.7. Header Compression 448 Header compression as defined in RFC 6282 [5], which specifies the 449 compression format for IPv6 datagrams on top of IEEE 802.15.4, is 450 REQUIRED in this document as the basis for IPv6 header compression on 451 top of NFC. All headers MUST be compressed according to RFC 6282 452 encoding formats. 454 Therefore, IPv6 header compression in RFC 6282 [5] MUST be 455 implemented. Further, implementations MAY also support Generic 456 Header Compression (GHC) of RFC 7400 [11]. 458 If a 16-bit address is required as a short address, it MUST be formed 459 by padding the 6-bit NFC link-layer (node) address to the left with 460 zeros as shown in Figure 7. 462 0 1 463 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 464 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 465 | Padding(all zeros)| NFC Addr. | 466 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 468 Figure 7: NFC short address format 470 4.8. Fragmentation and Reassembly 472 NFC provides fragmentation and reassembly (FAR) for payloads from 128 473 bytes up to 2176 bytes as mentioned in Section 3.4. The MTU of a 474 general IPv6 packet can fit into a single NFC link frame. Therefore, 475 the FAR functionality as defined in RFC 4944, which specifies the 476 fragmentation methods for IPv6 datagrams on top of IEEE 802.15.4, MAY 477 NOT be required as the basis for IPv6 datagram FAR on top of NFC. 478 The NFC link connection for IPv6 over NFC MUST be configured with an 479 equivalent MIU size to fit the MTU of IPv6 Packet. If NFC devices 480 support extension of the MTU, the MIUX value is 0x480 in order to fit 481 the MTU (1280 bytes) of a IPv6 packet. 483 4.9. Unicast Address Mapping 485 The address resolution procedure for mapping IPv6 non-multicast 486 addresses into NFC link-layer addresses follows the general 487 description in Section 7.2 of RFC 4861 [9], unless otherwise 488 specified. 490 The Source/Target link-layer Address option has the following form 491 when the addresses are 6-bit NFC link-layer (node) addresses. 493 0 1 494 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 495 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 496 | Type | Length=1 | 497 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 498 | | 499 +- Padding (all zeros) -+ 500 | | 501 +- +-+-+-+-+-+-+ 502 | | NFC Addr. | 503 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 505 Figure 8: Unicast address mapping 507 Option fields: 509 Type: 511 1: for Source Link-layer address. 513 2: for Target Link-layer address. 515 Length: 517 This is the length of this option (including the type and 518 length fields) in units of 8 octets. The value of this field 519 is 1 for 6-bit NFC node addresses. 521 NFC address: 523 The 6-bit address in canonical bit order. This is the unicast 524 address the interface currently responds to. 526 4.10. Multicast Address Mapping 528 All IPv6 multicast packets MUST be sent to NFC Destination Address, 529 0x3F (broadcast) and be filtered at the IPv6 layer. When represented 530 as a 16-bit address in a compressed header, it MUST be formed by 531 padding on the left with a zero. In addition, the NFC Destination 532 Address, 0x3F, MUST NOT be used as a unicast NFC address of SSAP or 533 DSAP. 535 0 1 536 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 537 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 538 | Padding(all zeros)|1 1 1 1 1 1| 539 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 541 Figure 9: Multicast address mapping 543 5. Internet Connectivity Scenarios 545 As two typical scenarios, the NFC network can be isolated and 546 connected to the Internet. 548 5.1. NFC-enabled Device Connected to the Internet 550 One of the key applications of using IPv6 over NFC is securely 551 transmitting IPv6 packets because the RF distance between 6LN and 552 6LBR is typically within 10 cm. If any third party wants to hack 553 into the RF between them, it must come to nearly touch them. 554 Applications can choose which kinds of air interfaces (e.g., BT-LE, 555 Wi-Fi, NFC, etc.) to send data depending on the characteristics of 556 the data. 558 Figure 10 illustrates an example of an NFC-enabled device network 559 connected to the Internet. The distance between 6LN and 6LBR is 560 typically 10 cm or less. If there is any laptop computers close to a 561 user, it will become the a 6LBR. Additionally, when the user mounts 562 an NFC-enabled air interface adapter (e.g., portable NFC dongle) on 563 the close laptop PC, the user's NFC-enabled device (6LN) can 564 communicate with the laptop PC (6LBR) within 10 cm distance. 566 ************ 567 6LN ------------------- 6LBR -----* Internet *------- CN 568 | (dis. 10 cm or less) | ************ | 569 | | | 570 | <-------- NFC -------> | <----- IPv6 packet ------> | 571 | (IPv6 over NFC packet) | | 573 Figure 10: NFC-enabled device network connected to the Internet 575 5.2. Isolated NFC-enabled Device Network 577 In some scenarios, the NFC-enabled device network may transiently be 578 a simple isolated network as shown in the Figure 11. 580 6LN ---------------------- 6LR ---------------------- 6LN 581 | (10 cm or less) | (10 cm or less) | 582 | | | 583 | <--------- NFC --------> | <--------- NFC --------> | 584 | (IPv6 over NFC packet) | (IPv6 over NFC packet) | 586 Figure 11: Isolated NFC-enabled device network 588 In mobile phone markets, applications are designed and made by user 589 developers. They may image interesting applications, where three or 590 more mobile phones touch or attach each other to accomplish 591 outstanding performance. 593 6. IANA Considerations 595 There are no IANA considerations related to this document. 597 7. Security Considerations 599 When interface identifiers (IIDs) are generated, devices and users 600 are required to consider mitigating various threats, such as 601 correlation of activities over time, location tracking, device- 602 specific vulnerability exploitation, and address scanning. 604 IPv6-over-NFC is, in practice, not used for long-lived links for big 605 size data transfer or multimedia streaming, but used for extremely 606 short-lived links (i.e., single touch-based approaches) for ID 607 verification and mobile payment. This will mitigate the threat of 608 correlation of activities over time. 610 IPv6-over-NFC uses an IPv6 interface identifier formed from a "Short 611 Address" and a set of well-known constant bits (such as padding with 612 '0's) for the modified EUI-64 format. However, the short address of 613 NFC link layer (LLC) is not generated as a physically permanent value 614 but logically generated for each connection. Thus, every single 615 touch connection can use a different short address of NFC link with 616 an extremely short-lived link. This can mitigate address scanning as 617 well as location tracking and device-specific vulnerability 618 exploitation. 620 However, malicious tries for one connection of a long-lived link with 621 NFC technology are not secure, so the method of deriving interface 622 identifiers from 6-bit NFC Link layer addresses is intended to 623 preserve global uniqueness when it is possible. Therefore, it 624 requires a way to protect from duplication through accident or 625 forgery and to define a way to include sufficient bit of entropy in 626 the IPv6 interface identifier, such as random EUI-64. 628 8. Acknowledgements 630 We are grateful to the members of the IETF 6lo working group. 632 Michael Richardson, Suresh Krishnan, Pascal Thubert, Carsten Bormann, 633 and Alexandru Petrescu have provided valuable feedback for this 634 draft. 636 9. References 638 9.1. Normative References 640 [1] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, 641 "Transmission of IPv6 Packets over IEEE 802.15.4 642 Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007, 643 . 645 [2] Bradner, S., "Key words for use in RFCs to Indicate 646 Requirement Levels", BCP 14, RFC 2119, 647 DOI 10.17487/RFC2119, March 1997, 648 . 650 [3] "NFC Logical Link Control Protocol version 1.3", NFC Forum 651 Technical Specification , March 2016. 653 [4] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. 654 Bormann, "Neighbor Discovery Optimization for IPv6 over 655 Low-Power Wireless Personal Area Networks (6LoWPANs)", 656 RFC 6775, DOI 10.17487/RFC6775, November 2012, 657 . 659 [5] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6 660 Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, 661 DOI 10.17487/RFC6282, September 2011, 662 . 664 [6] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 665 Address Autoconfiguration", RFC 4862, 666 DOI 10.17487/RFC4862, September 2007, 667 . 669 [7] Hinden, R. and S. Deering, "IP Version 6 Addressing 670 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 671 2006, . 673 [8] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic 674 Host Configuration Protocol (DHCP) version 6", RFC 3633, 675 DOI 10.17487/RFC3633, December 2003, 676 . 678 [9] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 679 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 680 DOI 10.17487/RFC4861, September 2007, 681 . 683 [10] Carpenter, B. and S. Jiang, "Significance of IPv6 684 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 685 February 2014, . 687 [11] Bormann, C., "6LoWPAN-GHC: Generic Header Compression for 688 IPv6 over Low-Power Wireless Personal Area Networks 689 (6LoWPANs)", RFC 7400, DOI 10.17487/RFC7400, November 690 2014, . 692 9.2. Informative References 694 [12] "Near Field Communication - Interface and Protocol (NFCIP- 695 1) 3rd Ed.", ECMA-340 , June 2013. 697 Authors' Addresses 699 Younghwan Choi 700 Electronics and Telecommunications Research Institute 701 218 Gajeongno, Yuseong 702 Daejeon 305-700 703 Korea 705 Phone: +82 42 860 1429 706 Email: yhc@etri.re.kr 707 Yong-Geun Hong 708 Electronics and Telecommunications Research Institute 709 161 Gajeong-Dong Yuseung-Gu 710 Daejeon 305-700 711 Korea 713 Phone: +82 42 860 6557 714 Email: yghong@etri.re.kr 716 Joo-Sang Youn 717 DONG-EUI University 718 176 Eomgwangno Busan_jin_gu 719 Busan 614-714 720 Korea 722 Phone: +82 51 890 1993 723 Email: joosang.youn@gmail.com 725 Dongkyun Kim 726 Kyungpook National University 727 80 Daehak-ro, Buk-gu 728 Daegu 702-701 729 Korea 731 Phone: +82 53 950 7571 732 Email: dongkyun@knu.ac.kr 734 JinHyouk Choi 735 Samsung Electronics Co., 736 129 Samsung-ro, Youngdong-gu 737 Suwon 447-712 738 Korea 740 Phone: +82 2 2254 0114 741 Email: jinchoe@samsung.com