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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) -- Possible downref: Non-RFC (?) normative reference: ref. 'Clause9' ** Obsolete normative reference: RFC 2460 (Obsoleted by RFC 8200) ** Obsolete normative reference: RFC 3315 (Obsoleted by RFC 8415) ** Obsolete normative reference: RFC 4941 (Obsoleted by RFC 8981) Summary: 3 errors (**), 0 flaws (~~), 2 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 6Lo Working Group K. Lynn, Ed. 3 Internet-Draft Verizon Labs 4 Intended status: Standards Track J. Martocci 5 Expires: May 4, 2017 Johnson Controls 6 C. Neilson 7 Delta Controls 8 S. Donaldson 9 Honeywell 10 October 31, 2016 12 Transmission of IPv6 over MS/TP Networks 13 draft-ietf-6lo-6lobac-06 15 Abstract 17 Master-Slave/Token-Passing (MS/TP) is a medium access control method 18 for the RS-485 physical layer, which is used extensively in building 19 automation networks. This specification defines the frame format for 20 transmission of IPv6 packets and the method of forming link-local and 21 statelessly autoconfigured IPv6 addresses on MS/TP networks. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at http://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on May 4, 2017. 40 Copyright Notice 42 Copyright (c) 2016 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (http://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 58 2. MS/TP Mode for IPv6 . . . . . . . . . . . . . . . . . . . . . 6 59 3. Addressing Modes . . . . . . . . . . . . . . . . . . . . . . 6 60 4. Maximum Transmission Unit (MTU) . . . . . . . . . . . . . . . 6 61 5. LoBAC Adaptation Layer . . . . . . . . . . . . . . . . . . . 7 62 6. Stateless Address Autoconfiguration . . . . . . . . . . . . . 8 63 7. IPv6 Link Local Address . . . . . . . . . . . . . . . . . . . 8 64 8. Unicast Address Mapping . . . . . . . . . . . . . . . . . . . 9 65 9. Multicast Address Mapping . . . . . . . . . . . . . . . . . . 9 66 10. Header Compression . . . . . . . . . . . . . . . . . . . . . 10 67 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 68 12. Security Considerations . . . . . . . . . . . . . . . . . . . 10 69 13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11 70 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 71 Appendix A. Abstract MAC Interface . . . . . . . . . . . . . . . 14 72 Appendix B. Consistent Overhead Byte Stuffing [COBS] . . . . . . 16 73 Appendix C. Encoded CRC-32K [CRC32K] . . . . . . . . . . . . . . 19 74 Appendix D. Example 6LoBAC Packet Decode . . . . . . . . . . . . 22 75 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27 77 1. Introduction 79 Master-Slave/Token-Passing (MS/TP) is a medium access control (MAC) 80 protocol for the RS-485 [TIA-485-A] physical layer, which is used 81 extensively in building automation networks. This specification 82 defines the frame format for transmission of IPv6 [RFC2460] packets 83 and the method of forming link-local and statelessly autoconfigured 84 IPv6 addresses on MS/TP networks. The general approach is to adapt 85 elements of the 6LoWPAN specifications [RFC4944], [RFC6282], and 86 [RFC6775], where noted, to constrained wired networks. 88 An MS/TP device is typically based on a low-cost microcontroller with 89 limited processing power and memory. Together with low data rates 90 and a small MAC address space, these constraints are similar to those 91 faced in 6LoWPAN networks and suggest some elements of that solution 92 might be leveraged. MS/TP differs significantly from 6LoWPAN in at 93 least three respects: a) MS/TP devices typically have a continuous 94 source of power, b) all MS/TP devices on a segment can communicate 95 directly so there are no hidden node or mesh routing issues, and c) 96 recent changes to MS/TP provide support for larger payloads, 97 eliminating the need for fragmentation and reassembly below IPv6. 99 The following sections provide a brief overview of MS/TP, then 100 describe how to form IPv6 addresses and encapsulate IPv6 packets in 101 MS/TP frames. This document also specifies a header compression 102 mechanism, based on [RFC6282], that is REQUIRED in order to reduce 103 latency and make IPv6 practical on MS/TP networks. 105 1.1. Requirements Language 107 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 108 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 109 document are to be interpreted as described in [RFC2119]. 111 1.2. Abbreviations Used 113 ASHRAE: American Society of Heating, Refrigerating, and Air- 114 Conditioning Engineers (http://www.ashrae.org) 116 BACnet: An ISO/ANSI/ASHRAE Standard Data Communication Protocol 117 for Building Automation and Control Networks 119 CRC: Cyclic Redundancy Check 121 MAC: Medium Access Control 123 MSDU: MAC Service Data Unit (MAC client data) 125 MTU: Maximum Transmission Unit 127 UART: Universal Asynchronous Transmitter/Receiver 129 1.3. MS/TP Overview 131 This section provides a brief overview of MS/TP, which is specified 132 in ANSI/ASHRAE 135-2012 (BACnet) Clause 9 [Clause9] and included 133 herein by reference. BACnet [Clause9] also covers physical layer 134 deployment options. 136 MS/TP is designed to enable multidrop networks over shielded twisted 137 pair wiring. It can support network segments up to 1000 meters in 138 length at a data rate of 115,200 bit/s, or segments up to 1200 meters 139 in length at lower bit rates. An MS/TP link requires only a UART, an 140 RS-485 [TIA-485-A] transceiver with a driver that can be disabled, 141 and a 5 ms resolution timer. These features make MS/TP a cost- 142 effective field bus for the most numerous and least expensive devices 143 in a building automation network. 145 The differential signaling used by [TIA-485-A] requires a contention- 146 free MAC. MS/TP uses a token to control access to a multidrop bus. 147 A master node may initiate the transmission of a data frame when it 148 holds the token. After sending at most a configured maximum number 149 of data frames, a master node passes the token to the next master 150 node (as determined by MAC address). If present on the link, legacy 151 MS/TP implementations (including all slave nodes) ignore the frame 152 format defined in this specification. 154 BACnet Addendum 135-2012an [Addendum_an] defines a range of Frame 155 Type values to designate frames that contain larger data and data CRC 156 fields, encoded using Consistent Overhead Byte Stuffing [COBS] (see 157 Appendix B). The purpose of COBS encoding is to eliminate preamble 158 sequences from the Encoded Data and Encoded CRC-32K fields. The 159 maximum length of an MSDU as defined by this specification is 1500 160 octets (before encoding). The Encoded Data is covered by a 32-bit 161 CRC [CRC32K] (see Appendix C). The CRC-32K is then COBS encoded. 163 MS/TP COBS-encoded frames have the following format: 165 0 1 2 3 166 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 167 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 168 | 0x55 | 0xFF | Frame Type | DA | 169 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 170 | SA | Length (MS octet first) | Header CRC | 171 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 172 . . 173 . Encoded Data (2 - 1506 octets) . 174 . . 175 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 176 | | Encoded CRC-32K (5 octets) | 177 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ 178 | | optional 0xFF | 179 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 181 Figure 1: MS/TP COBS-Encoded Frame Format 183 MS/TP COBS-encoded frame fields have the following descriptions: 185 Preamble two octet preamble: 0x55, 0xFF 186 Frame Type one octet 187 Destination Address one octet address 188 Source Address one octet address 189 Length two octets, most significant octet first 190 Header CRC one octet 191 Encoded Data 2 - 1506 octets (see Appendix B) 192 Encoded CRC-32K five octets (see Appendix C) 193 (pad) (optional) at most one octet of trailer: 0xFF 195 The Frame Type is used to distinguish between different types of MAC 196 frames. The types relevant to this specification (in decimal) are: 198 0 Token 199 1 Poll For Master 200 2 Reply To Poll For Master 201 ... 202 34 IPv6 over MS/TP (LoBAC) Encapsulation 204 Frame Types 8 - 31 and 35 - 127 are reserved for assignment by 205 ASHRAE. Frame Types 32 - 127 designate COBS-encoded frames and MUST 206 convey Encoded Data and Encoded CRC-32K fields. All master nodes 207 MUST understand Token, Poll For Master, and Reply to Poll For Master 208 control frames. See Section 2 for additional details. 210 The Destination and Source Addresses are each one octet in length. 211 See Section 3 for additional details. 213 For COBS-encoded frames, the Length field indicates the size of the 214 [COBS] Encoded Data field in octets, plus three. (This adjustment is 215 required in order for legacy MS/TP devices to ignore COBS-encoded 216 frames.) See Section 4 and Appendices for additional details. 218 The Header CRC field covers the Frame Type, Destination Address, 219 Source Address, and Length fields. The Header CRC generation and 220 check procedures are specified in BACnet [Clause9]. 222 Use of the optional 0xFF trailer octet is discussed in BACnet 223 [Clause9]. 225 1.4. Goals and Constraints 227 The primary goal of this specification is to enable IPv6 directly on 228 wired end devices in building automation and control networks by 229 leveraging existing standards to the greatest extent possible. A 230 secondary goal is to co-exist with legacy MS/TP implementations. 231 Only the minimum changes necessary to support IPv6 over MS/TP were 232 specified in BACnet [Addendum_an] (see Section 1.3). 234 In order to co-exist with legacy devices, no changes are permitted to 235 the MS/TP addressing modes, frame header format, control frames, or 236 Master Node state machine as specified in BACnet [Clause9]. 238 2. MS/TP Mode for IPv6 240 ASHRAE has assigned an MS/TP Frame Type value of 34 to indicate IPv6 241 over MS/TP (LoBAC) Encapsulation. This falls within the range of 242 values that designate COBS-encoded data frames. 244 All MS/TP master nodes (including those that support IPv6) MUST 245 implement the Master Node state machine specified in BACnet [Clause9] 246 and handle Token, Poll For Master, and Reply to Poll For Master 247 control frames. MS/TP master nodes that support IPv6 MUST also 248 implement the Receive Frame state machine specified in [Clause9] as 249 extended by BACnet [Addendum_an]. 251 All MS/TP nodes that support IPv6 MUST support a data rate of 115,200 252 bit/s and MAY optionally support lower data rates as defined in 253 BACnet [Clause9]. 255 3. Addressing Modes 257 MS/TP node (MAC) addresses are one octet in length. The method of 258 assigning MAC addresses is outside the scope of this specification. 259 However, each MS/TP node on the link MUST have a unique address in 260 order to ensure correct MAC operation. 262 BACnet [Clause9] specifies that addresses 0 through 127 are valid for 263 master nodes. The method specified in Section 6 for creating a MAC- 264 layer-derived Interface Identifier (IID) ensures that an IID of all 265 zeros can never result. 267 A Destination Address of 255 (all nodes) indicates a MAC-layer 268 broadcast. MS/TP does not support multicast, therefore all IPv6 269 multicast packets MUST be broadcast at the MAC layer and filtered at 270 the IPv6 layer. A Source Address of 255 MUST NOT be used. 272 Hosts learn IPv6 prefixes via router advertisements according to 273 [RFC4861]. 275 4. Maximum Transmission Unit (MTU) 277 BACnet [Addendum_an] supports MSDUs up to 2032 octets in length. 278 This specification defines an MSDU length of at least 1280 octets and 279 at most 1500 octets (before encoding). This is sufficient to convey 280 the minimum MTU required by IPv6 [RFC2460] without the need for link- 281 layer fragmentation and reassembly. Support for an MSDU length of 282 1500 octets is RECOMMENDED. 284 5. LoBAC Adaptation Layer 286 The relatively low data rates of MS/TP dictate header compression as 287 a means to reduce latency. This section specifies an adaptation 288 layer to support compressed IPv6 headers as specified in Section 10. 289 IPv6 header compression MUST be implemented on all nodes. 291 Implementations MAY also support Generic Header Compression (GHC) 292 [RFC7400] for transport layer headers. A node implementing [RFC7400] 293 MUST probe its peers for GHC support before applying GHC. 295 The encapsulation format defined in this section (subsequently 296 referred to as the "LoBAC" encapsulation) comprises the MSDU of an 297 IPv6 over MS/TP frame. The LoBAC payload (i.e., an IPv6 packet) 298 follows an encapsulation header stack. LoBAC is a subset of the 299 LoWPAN encapsulation defined in [RFC4944] and extended by [RFC6282], 300 therefore the use of "LOWPAN" in literals below is intentional. The 301 primary difference between LoWPAN and LoBAC is omission of the Mesh, 302 Broadcast, Fragmentation, and LOWPAN_HC1 headers. 304 All LoBAC encapsulated datagrams transmitted over MS/TP are prefixed 305 by an encapsulation header stack consisting of a Dispatch value 306 followed by zero or more header fields. The only sequence currently 307 defined for LoBAC is the LOWPAN_IPHC header followed by payload, as 308 shown below: 310 +---------------+---------------+------...-----+ 311 | IPHC Dispatch | IPHC Header | Payload | 312 +---------------+---------------+------...-----+ 314 Figure 2: A LoBAC Encapsulated LOWPAN_IPHC Compressed IPv6 Datagram 316 The Dispatch value may be treated as an unstructured namespace. Only 317 a single pattern is used to represent current LoBAC functionality. 319 Pattern Header Type 320 +------------+-----------------------------------------------------+ 321 | 01 1xxxxx | LOWPAN_IPHC - LOWPAN_IPHC compressed IPv6 [RFC6282] | 322 +------------+-----------------------------------------------------+ 324 Figure 3: LoBAC Dispatch Value Bit Pattern 326 Other IANA-assigned 6LoWPAN Dispatch values do not apply to 6LoBAC 327 unless otherwise specified. 329 6. Stateless Address Autoconfiguration 331 This section defines how to obtain an IPv6 Interface Identifier. The 332 general procedure for creating a MAC-address-derived IID is described 333 in [RFC4291] Appendix A, "Creating Modified EUI-64 Format Interface 334 Identifiers", as updated by [RFC7136]. 336 The IID SHOULD NOT embed an [EUI-64] or any other globally unique 337 hardware identifier assigned to a device (see Section 12). 339 The Interface Identifier for link-local addresses SHOULD be formed by 340 concatenating a node's' 8-bit MS/TP MAC address to the seven octets 341 0x00, 0x00, 0x00, 0xFF, 0xFE, 0x00, 0x00. For example, an MS/TP MAC 342 address of hexadecimal value 0x4F results in the following IID: 344 |0 1|1 3|3 4|4 6| 345 |0 5|6 1|2 7|8 3| 346 +----------------+----------------+----------------+----------------+ 347 |0000000000000000|0000000011111111|1111111000000000|0000000001001111| 348 +----------------+----------------+----------------+----------------+ 350 This is the RECOMMENDED method of forming an IID for use in link- 351 local addresses, as it affords the most efficient header compression 352 provided by the LOWPAN_IPHC [RFC6282] format specified in Section 10. 354 A 64-bit random IID is RECOMMENDED for each globally scoped address 355 and SHOULD be locally generated according to one of the methods cited 356 in Section 12. A node that generates a 64-bit random IID MUST 357 register it with its local router(s) by sending a Neighbor 358 Solicitation (NS) message with the Address Registration Option (ARO) 359 and process Neighbor Advertisements (NA) according to [RFC6775]. 361 An IPv6 address prefix used for stateless autoconfiguration [RFC4862] 362 of an MS/TP interface MUST have a length of 64 bits. 364 7. IPv6 Link Local Address 366 The IPv6 link-local address [RFC4291] for an MS/TP interface is 367 formed by appending the Interface Identifier, as defined above, to 368 the prefix FE80::/64. 370 10 bits 54 bits 64 bits 371 +----------+-----------------------+----------------------------+ 372 |1111111010| (zeros) | Interface Identifier | 373 +----------+-----------------------+----------------------------+ 375 8. Unicast Address Mapping 377 The address resolution procedure for mapping IPv6 non-multicast 378 addresses into MS/TP MAC-layer addresses follows the general 379 description in Section 7.2 of [RFC4861], unless otherwise specified. 381 The Source/Target Link-layer Address option has the following form 382 when the addresses are 8-bit MS/TP MAC-layer (node) addresses. 384 0 1 385 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 386 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 387 | Type | Length=1 | 388 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 389 | 0x00 | MS/TP Address | 390 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 391 | | 392 + Padding (all zeros) + 393 | | 394 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 396 Option fields: 398 Type: 400 1: for Source Link-layer address. 402 2: for Target Link-layer address. 404 Length: This is the length of this option (including the type and 405 length fields) in units of 8 octets. The value of this field is 1 406 for 8-bit MS/TP MAC addresses. 408 MS/TP Address: The 8-bit address in canonical bit order [RFC2469]. 409 This is the unicast address the interface currently responds to. 411 9. Multicast Address Mapping 413 All IPv6 multicast packets MUST be sent to MS/TP Destination Address 414 255 (broadcast) and filtered at the IPv6 layer. When represented as 415 a 16-bit address in a compressed header (see Section 10), it MUST be 416 formed by padding on the left with a zero: 418 0 1 419 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 420 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 421 | 0x00 | 0xFF | 422 +-+-+-+-+-+-+-+-+---------------+ 424 10. Header Compression 426 LoBAC uses LOWPAN_IPHC IPv6 compression, which is specified in 427 [RFC6282] and included herein by reference. This section will simply 428 identify substitutions that should be made when interpreting the text 429 of [RFC6282]. 431 In general the following substitutions should be made: 433 - Replace instances of "6LoWPAN" with "MS/TP network" 435 - Replace instances of "IEEE 802.15.4 address" with "MS/TP address" 437 When a 16-bit address is called for (i.e., an IEEE 802.15.4 "short 438 address") it MUST be formed by padding the MS/TP address to the left 439 with a zero: 441 0 1 442 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 443 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 444 | 0x00 | MS/TP address | 445 +-+-+-+-+-+-+-+-+---------------+ 447 If LOWPAN_IPHC compression [RFC6282] is used with context, the 448 router(s) directly attached to the MS/TP segment MUST disseminate the 449 6LoWPAN Context Option (6CO) according to [RFC6775], Section 7.2. 451 11. IANA Considerations 453 This document uses values previously reserved by [RFC4944] and 454 [RFC6282] and makes no further requests of IANA. 456 Note to RFC Editor: this section may be removed upon publication. 458 12. Security Considerations 460 Globally scoped addresses that contain IIDs generated using MS/TP 461 node addresses may expose a network to address scanning attacks. For 462 this reason, it is RECOMMENDED that a different (but stable) IID be 463 generated for each globally scoped address in use according to, for 464 example, [RFC3315], [RFC3972], [RFC4941], [RFC5535], or [RFC7217]. 466 MS/TP networks are by definition wired and not susceptible to casual 467 eavesdropping. By the same token, MS/TP nodes are stationary and 468 correlation of activities or location tracking of individuals is 469 unlikely. See [I-D.ietf-6lo-privacy-considerations] for a full 470 discussion of mitigation of the threats posed to constrained nodes. 472 13. Acknowledgments 474 We are grateful to the authors of [RFC4944] and members of the IETF 475 6LoWPAN working group; this document borrows liberally from their 476 work. Ralph Droms and Brian Haberman provided indispensable guidance 477 and support from the outset. Peter van der Stok, James Woodyatt, and 478 Carsten Bormann provided detailed reviews. Stuart Cheshire invented 479 the very clever COBS encoding. Michael Osborne made the critical 480 observation that separately encoding the data and CRC32K fields would 481 allow the CRC to be calculated on-the-fly. Alexandru Petrescu, Brian 482 Frank, Geoff Mulligan, and Don Sturek offered valuable comments. 484 14. References 486 14.1. Normative References 488 [Addendum_an] 489 ASHRAE, "ANSI/ASHRAE Addenda an, at, au, av, aw, ax, and 490 az to ANSI/ASHRAE Standard 135-2012, BACnet - A Data 491 Communication Protocol for Building Automation and Control 492 Networks", July 2014, 493 . 496 [Clause9] American Society of Heating, Refrigerating, and Air- 497 Conditioning Engineers, "BACnet - A Data Communication 498 Protocol for Building Automation and Control Networks", 499 ANSI/ASHRAE 135-2012 (Clause 9), March 2013. 501 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 502 Requirement Levels", BCP 14, RFC 2119, 503 DOI 10.17487/RFC2119, March 1997, 504 . 506 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 507 (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460, 508 December 1998, . 510 [RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins, 511 C., and M. Carney, "Dynamic Host Configuration Protocol 512 for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July 513 2003, . 515 [RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)", 516 RFC 3972, DOI 10.17487/RFC3972, March 2005, 517 . 519 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 520 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 521 2006, . 523 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 524 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 525 DOI 10.17487/RFC4861, September 2007, 526 . 528 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 529 Address Autoconfiguration", RFC 4862, 530 DOI 10.17487/RFC4862, September 2007, 531 . 533 [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy 534 Extensions for Stateless Address Autoconfiguration in 535 IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007, 536 . 538 [RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, 539 "Transmission of IPv6 Packets over IEEE 802.15.4 540 Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007, 541 . 543 [RFC5535] Bagnulo, M., "Hash-Based Addresses (HBA)", RFC 5535, 544 DOI 10.17487/RFC5535, June 2009, 545 . 547 [RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6 548 Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, 549 DOI 10.17487/RFC6282, September 2011, 550 . 552 [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. 553 Bormann, "Neighbor Discovery Optimization for IPv6 over 554 Low-Power Wireless Personal Area Networks (6LoWPANs)", 555 RFC 6775, DOI 10.17487/RFC6775, November 2012, 556 . 558 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 559 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 560 February 2014, . 562 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 563 Interface Identifiers with IPv6 Stateless Address 564 Autoconfiguration (SLAAC)", RFC 7217, 565 DOI 10.17487/RFC7217, April 2014, 566 . 568 [RFC7400] Bormann, C., "6LoWPAN-GHC: Generic Header Compression for 569 IPv6 over Low-Power Wireless Personal Area Networks 570 (6LoWPANs)", RFC 7400, DOI 10.17487/RFC7400, November 571 2014, . 573 14.2. Informative References 575 [COBS] Cheshire, S. and M. Baker, "Consistent Overhead Byte 576 Stuffing", IEEE/ACM TRANSACTIONS ON NETWORKING, VOL.7, 577 NO.2 , April 1999, 578 . 580 [CRC32K] Koopman, P., "32-Bit Cyclic Redundancy Codes for Internet 581 Applications", IEEE/IFIP International Conference on 582 Dependable Systems and Networks (DSN 2002) , June 2002, 583 . 586 [EUI-64] IEEE, "Guidelines for 64-bit Global Identifier (EUI-64) 587 Registration Authority", March 1997, 588 . 591 [I-D.ietf-6lo-privacy-considerations] 592 Thaler, D., "Privacy Considerations for IPv6 Adaptation 593 Layer Mechanisms", draft-ietf-6lo-privacy- 594 considerations-04 (work in progress), October 2016. 596 [IEEE.802.3] 597 "Information technology - Telecommunications and 598 information exchange between systems - Local and 599 metropolitan area networks - Specific requirements - Part 600 3: Carrier Sense Multiple Access with Collision Detection 601 (CMSA/CD) Access Method and Physical Layer 602 Specifications", IEEE Std 802.3-2012, December 2012, 603 . 605 [RFC2469] Narten, T. and C. Burton, "A Caution On The Canonical 606 Ordering Of Link-Layer Addresses", RFC 2469, 607 DOI 10.17487/RFC2469, December 1998, 608 . 610 [TIA-485-A] 611 Telecommunications Industry Association, "TIA-485-A, 612 Electrical Characteristics of Generators and Receivers for 613 Use in Balanced Digital Multipoint Systems (ANSI/TIA/EIA- 614 485-A-98) (R2003)", March 2003. 616 Appendix A. Abstract MAC Interface 618 This Appendix is informative and not part of the standard. 620 BACnet [Clause9] provides support for MAC-layer clients through its 621 SendFrame and ReceivedDataNoReply procedures. However, it does not 622 define a network-protocol independent abstract interface for the MAC. 623 This is provided below as an aid to implementation. 625 A.1. MA-DATA.request 627 A.1.1. Function 629 This primitive defines the transfer of data from a MAC client entity 630 to a single peer entity or multiple peer entities in the case of a 631 broadcast address. 633 A.1.2. Semantics of the Service Primitive 635 The semantics of the primitive are as follows: 637 MA-DATA.request ( 638 destination_address, 639 source_address, 640 data, 641 type 642 ) 644 The 'destination_address' parameter may specify either an individual 645 or a broadcast MAC entity address. It must contain sufficient 646 information to create the Destination Address field (see Section 1.3) 647 that is prepended to the frame by the local MAC sublayer entity. The 648 'source_address' parameter, if present, must specify an individual 649 MAC address. If the source_address parameter is omitted, the local 650 MAC sublayer entity will insert a value associated with that entity. 652 The 'data' parameter specifies the MAC service data unit (MSDU) to be 653 transferred by the MAC sublayer entity. There is sufficient 654 information associated with the MSDU for the MAC sublayer entity to 655 determine the length of the data unit. 657 The 'type' parameter specifies the value of the MS/TP Frame Type 658 field that is prepended to the frame by the local MAC sublayer 659 entity. 661 A.1.3. When Generated 663 This primitive is generated by the MAC client entity whenever data 664 shall be transferred to a peer entity or entities. This can be in 665 response to a request from higher protocol layers or from data 666 generated internally to the MAC client, such as a Token frame. 668 A.1.4. Effect on Receipt 670 Receipt of this primitive will cause the MAC entity to insert all MAC 671 specific fields, including Destination Address, Source Address, Frame 672 Type, and any fields that are unique to the particular media access 673 method, and pass the properly formed frame to the lower protocol 674 layers for transfer to the peer MAC sublayer entity or entities. 676 A.2. MA-DATA.indication 678 A.2.1. Function 680 This primitive defines the transfer of data from the MAC sublayer 681 entity to the MAC client entity or entities in the case of a 682 broadcast address. 684 A.2.2. Semantics of the Service Primitive 686 The semantics of the primitive are as follows: 688 MA-DATA.indication ( 689 destination_address, 690 source_address, 691 data, 692 type 693 ) 695 The 'destination_address' parameter may be either an individual or a 696 broadcast address as specified by the Destination Address field of 697 the incoming frame. The 'source_address' parameter is an individual 698 address as specified by the Source Address field of the incoming 699 frame. 701 The 'data' parameter specifies the MAC service data unit (MSDU) as 702 received by the local MAC entity. There is sufficient information 703 associated with the MSDU for the MAC sublayer client to determine the 704 length of the data unit. 706 The 'type' parameter is the value of the MS/TP Frame Type field of 707 the incoming frame. 709 A.2.3. When Generated 711 The MA_DATA.indication is passed from the MAC sublayer entity to the 712 MAC client entity or entities to indicate the arrival of a frame to 713 the local MAC sublayer entity that is destined for the MAC client. 714 Such frames are reported only if they are validly formed, received 715 without error, and their destination address designates the local MAC 716 entity. Frames destined for the MAC Control sublayer are not passed 717 to the MAC client. 719 A.2.4. Effect on Receipt 721 The effect of receipt of this primitive by the MAC client is 722 unspecified. 724 Appendix B. Consistent Overhead Byte Stuffing [COBS] 726 This Appendix is informative and not part of the standard. 728 BACnet [Addendum_an] corrects a long-standing issue with the MS/TP 729 specification; namely that preamble sequences were not escaped 730 whenever they appeared in the Data or Data CRC fields. In rare 731 cases, this resulted in dropped frames due to loss of frame 732 synchronization. The solution is to encode the Data and 32-bit Data 733 CRC fields before transmission using Consistent Overhead Byte 734 Stuffing [COBS] and decode these fields upon reception. 736 COBS is a run-length encoding method that nominally removes '0x00' 737 octets from its input. Any selected octet value may be removed by 738 XOR'ing that value with each octet of the COBS output. BACnet 739 [Addendum_an] specifies the preamble octet '0x55' for removal. 741 The minimum overhead of COBS is one octet per encoded field. The 742 worst-case overhead in long fields is bounded to one octet per 254, 743 or less than 0.4%, as described in [COBS]. 745 Frame encoding proceeds logically in two passes. The Encoded Data 746 field is prepared by passing the MSDU through the COBS encoder and 747 XOR'ing the preamble octet '0x55' with each octet of the output. The 748 Encoded CRC-32K field is then prepared by calculating a CRC-32K over 749 the Encoded Data field and formatting it for transmission as 750 described in Appendix C. The combined length of these fields, minus 751 two octets for compatibility with existing MS/TP devices, is placed 752 in the MS/TP header Length field before transmission. 754 Example COBS encoder and decoder functions are shown below for 755 illustration. Complete examples of use and test vectors are provided 756 in BACnet [Addendum_an]. 758 #include 759 #include 761 /* 762 * Encodes 'length' octets of data located at 'from' and 763 * writes one or more COBS code blocks at 'to', removing any 764 * 'mask' octets that may present be in the encoded data. 765 * Returns the length of the encoded data. 766 */ 768 size_t 769 cobs_encode (uint8_t *to, const uint8_t *from, size_t length, 770 uint8_t mask) 771 { 772 size_t code_index = 0; 773 size_t read_index = 0; 774 size_t write_index = 1; 775 uint8_t code = 1; 776 uint8_t data, last_code; 778 while (read_index < length) { 779 data = from[read_index++]; 780 /* 781 * In the case of encountering a non-zero octet in the data, 782 * simply copy input to output and increment the code octet. 783 */ 784 if (data != 0) { 785 to[write_index++] = data ^ mask; 786 code++; 787 if (code != 255) 788 continue; 789 } 790 /* 791 * In the case of encountering a zero in the data or having 792 * copied the maximum number (254) of non-zero octets, store 793 * the code octet and reset the encoder state variables. 794 */ 795 last_code = code; 796 to[code_index] = code ^ mask; 797 code_index = write_index++; 798 code = 1; 799 } 800 /* 801 * If the last chunk contains exactly 254 non-zero octets, then 802 * this exception is handled above (and returned length must be 803 * adjusted). Otherwise, encode the last chunk normally, as if 804 * a "phantom zero" is appended to the data. 805 */ 807 if ((last_code == 255) && (code == 1)) 808 write_index--; 809 else 810 to[code_index] = code ^ mask; 812 return write_index; 813 } 814 #include 815 #include 817 /* 818 * Decodes 'length' octets of data located at 'from' and 819 * writes the original client data at 'to', restoring any 820 * 'mask' octets that may present in the encoded data. 821 * Returns the length of the encoded data or zero if error. 822 */ 823 size_t 824 cobs_decode (uint8_t *to, const uint8_t *from, size_t length, 825 uint8_t mask) 826 { 827 size_t read_index = 0; 828 size_t write_index = 0; 829 uint8_t code, last_code; 831 while (read_index < length) { 832 code = from[read_index] ^ mask; 833 last_code = code; 834 /* 835 * Sanity check the encoding to prevent the while() loop below 836 * from overrunning the output buffer. 837 */ 838 if (read_index + code > length) 839 return 0; 841 read_index++; 842 while (--code > 0) 843 to[write_index++] = from[read_index++] ^ mask; 844 /* 845 * Restore the implicit zero at the end of each decoded block 846 * except when it contains exactly 254 non-zero octets or the 847 * end of data has been reached. 848 */ 849 if ((last_code != 255) && (read_index < length)) 850 to[write_index++] = 0; 851 } 852 return write_index; 853 } 855 Appendix C. Encoded CRC-32K [CRC32K] 857 This Appendix is informative and not part of the standard. 859 Extending the payload of MS/TP to 1500 octets required upgrading the 860 Data CRC from 16 bits to 32 bits. P.Koopman has authored several 861 papers on evaluating CRC polynomials for network applications. In 863 [CRC32K], he surveyed the entire 32-bit polynomial space and noted 864 some that exceed the [IEEE.802.3] polynomial in performance. BACnet 865 [Addendum_an] specifies the CRC-32K (Koopman) polynomial. 867 The specified use of the calc_crc32K() function is as follows. 868 Before a frame is transmitted, 'crc_value' is initialized to all 869 ones. After passing each octet of the [COBS] Encoded Data through 870 the function, the ones complement of the resulting 'crc_value' is 871 arranged in LSB-first order and is itself [COBS] encoded. The length 872 of the resulting Encoded CRC-32K field is always five octets. 874 Upon reception of a frame, 'crc_value' is initialized to all ones. 875 The octets of the Encoded Data field are accumulated by the 876 calc_crc32K() function before decoding. The Encoded CRC-32K field is 877 then decoded and the resulting four octets are accumulated by the 878 calc_crc32K() function. If the result is the expected residue value 879 'CRC32K_RESIDUE', then the frame was received correctly. 881 An example CRC-32K function in shown below for illustration. 882 Complete examples of use and test vectors are provided in BACnet 883 [Addendum_an]. 885 #include 887 /* See BACnet Addendum 135-2012an, section G.3.2 */ 888 #define CRC32K_INITIAL_VALUE (0xFFFFFFFF) 889 #define CRC32K_RESIDUE (0x0843323B) 891 /* CRC-32K polynomial, 1 + x**1 + ... + x**30 (+ x**32) */ 892 #define CRC32K_POLY (0xEB31D82E) 894 /* 895 * Accumulate 'data_value' into the CRC in 'crc_value'. 896 * Return updated CRC. 897 * 898 * Note: crc_value must be set to CRC32K_INITIAL_VALUE 899 * before initial call. 900 */ 901 uint32_t 902 calc_crc32K (uint8_t data_value, uint32_t crc_value) 903 { 904 int b; 906 for (b = 0; b < 8; b++) { 907 if ((data_value & 1) ^ (crc_value & 1)) { 908 crc_value >>= 1; 909 crc_value ^= CRC32K_POLY; 910 } else { 911 crc_value >>= 1; 912 } 913 data_value >>= 1; 914 } 915 return crc_value; 916 } 918 Appendix D. Example 6LoBAC Packet Decode 920 This Appendix is informative and not part of the standard. 922 BACnet MS/TP, Src (2), Dst (1), IPv6 Encapsulation 923 Preamble 55: 0x55 924 Preamble FF: 0xff 925 Frame Type: IPv6 Encapsulation (34) 926 Destination Address: 1 927 Source Address: 2 928 Length: 537 929 Header CRC: 0x1c [correct] 930 Extended Data CRC: 0x9e7259e2 [correct] 931 6LoWPAN 932 IPHC Header 933 011. .... = Pattern: IP header compression (0x03) 934 ...1 1... .... .... = Traffic class and flow label: 935 Version, traffic class, and flow label 936 compressed (0x0003) 937 .... .0.. .... .... = Next header: Inline 938 .... ..00 .... .... = Hop limit: Inline (0x0000) 939 .... .... 1... .... = Context identifier extension: True 940 .... .... .1.. .... = Source address compression: Stateful 941 .... .... ..01 .... = Source address mode: 942 64-bits inline (0x0001) 943 .... .... .... 0... = Multicast address compression: False 944 .... .... .... .1.. = Destination address compression: 945 Stateful 946 .... .... .... ..10 = Destination address mode: 947 16-bits inline (0x0002) 948 0000 .... = Source context identifier: 0x00 949 .... 0000 = Destination context identifier: 0x00 950 [Source context: aaaa:: (aaaa::)] 951 [Destination context: aaaa:: (aaaa::)] 952 Next header: ICMPv6 (0x3a) 953 Hop limit: 63 954 Source: aaaa::1 (aaaa::1) 955 Destination: aaaa::ff:fe00:1 (aaaa::ff:fe00:1) 956 Internet Protocol Version 6, Src: aaaa::1 (aaaa::1), 957 Dst: aaaa::ff:fe00:1 (aaaa::ff:fe00:1) 958 0110 .... .... .... .... .... .... .... = Version: 6 959 .... 0000 0000 .... .... .... .... .... = Traffic class: 960 0x00000000 961 .... 0000 00.. .... .... .... .... .... = Differentiated 962 Services Field: 963 Default (0x00000000) 964 .... .... ..0. .... .... .... .... .... = ECN-Capable Transport 965 (ECT): Not set 966 .... .... ...0 .... .... .... .... .... = ECN-CE: Not set 967 .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000 968 Payload length: 518 969 Next header: ICMPv6 (58) 970 Hop limit: 63 971 Source: aaaa::1 (aaaa::1) 972 Destination: aaaa::ff:fe00:1 (aaaa::ff:fe00:1) 973 Internet Control Message Protocol v6 974 Type: Echo (ping) request (128) 975 Code: 0 976 Checksum: 0x783f [correct] 977 Identifier: 0x2ee5 978 Sequence: 2 979 [Response In: 5165] 980 Data (510 bytes) 981 Data: e4dbe8553ba0040008090a0b0c0d0e0f1011121314151617... 982 [Length: 510] 984 Frame (547 bytes): 985 55 ff 22 01 02 02 19 1c 56 2d 83 56 6f 6a 54 54 U.".....V-.VojTT 986 54 54 54 54 57 54 56 54 d5 50 2d 6a 7b b0 5c 57 TTTTWTVT.P-j{.\W 987 b1 8e bd 00 6e f5 51 ac 5d 5c 5f 5e 59 58 5b 5a ....n.Q.]\_^YX[Z 988 45 44 47 46 41 40 43 42 4d 4c 4f 4e 49 48 4b 4a EDGFA@CBMLONIHKJ 989 75 74 77 76 71 70 73 72 7d 7c 7f 7e 79 78 7b 7a utwvqpsr}|.~yx{z 990 65 64 67 66 61 60 63 62 6d 6c 6f 6e 69 68 6b 6a edgfa`cbmlonihkj 991 15 14 17 16 11 10 13 12 1d 1c 1f 1e 19 18 1b 1a ................ 992 05 04 07 06 01 00 03 02 0d 0c 0f 0e 09 08 0b 0a ................ 993 35 34 37 36 31 30 33 32 3d 3c 3f 3e 39 38 3b 3a 54761032=98;: 994 25 24 27 26 21 20 23 22 2d 2c 2f 2e 29 28 2b 2a %$'&! #"-,/.)(+* 995 d5 d4 d7 d6 d1 d0 d3 d2 dd dc df de d9 d8 db da ................ 996 c5 c4 c7 c6 c1 c0 c3 c2 cd cc cf ce c9 c8 cb ca ................ 997 f5 f4 f7 f6 f1 f0 f3 f2 fd fc ff fe f9 f8 fb fa ................ 998 e5 e4 e7 e6 e1 e0 e3 e2 ed ec ef ee e9 e8 eb ea ................ 999 95 94 97 96 91 90 93 92 9d 9c 9f 9e 99 98 9b 9a ................ 1000 85 84 87 86 81 80 83 82 8d 8c 8f 8e 89 88 8b 8a ................ 1001 b5 b4 b7 b6 b1 b0 b3 b2 bd bc bf be b9 b8 bb ba ................ 1002 a5 a4 a7 a6 a1 a0 a3 a2 ad ac af ae a9 a8 ab aa ................ 1003 ab 54 57 56 51 50 53 52 5d 5c 5f 5e 59 58 5b 5a .TWVQPSR]\_^YX[Z 1004 45 44 47 46 41 40 43 42 4d 4c 4f 4e 49 48 4b 4a EDGFA@CBMLONIHKJ 1005 75 74 77 76 71 70 73 72 7d 7c 7f 7e 79 78 7b 7a utwvqpsr}|.~yx{z 1006 65 64 67 66 61 60 63 62 6d 6c 6f 6e 69 68 6b 6a edgfa`cbmlonihkj 1007 15 14 17 16 11 10 13 12 1d 1c 1f 1e 19 18 1b 1a ................ 1008 05 04 07 06 01 00 03 02 0d 0c 0f 0e 09 08 0b 0a ................ 1009 35 34 37 36 31 30 33 32 3d 3c 3f 3e 39 38 3b 3a 54761032=98;: 1010 25 24 27 26 21 20 23 22 2d 2c 2f 2e 29 28 2b 2a %$'&! #"-,/.)(+* 1011 d5 d4 d7 d6 d1 d0 d3 d2 dd dc df de d9 d8 db da ................ 1012 c5 c4 c7 c6 c1 c0 c3 c2 cd cc cf ce c9 c8 cb ca ................ 1013 f5 f4 f7 f6 f1 f0 f3 f2 fd fc ff fe f9 f8 fb fa ................ 1014 e5 e4 e7 e6 e1 e0 e3 e2 ed ec ef ee e9 e8 eb ea ................ 1015 95 94 97 96 91 90 93 92 9d 9c 9f 9e 99 98 9b 9a ................ 1016 85 84 87 86 81 80 83 82 8d 8c 8f 8e 89 88 8b 8a ................ 1017 b5 b4 b7 b6 b1 b0 b3 b2 bd bc bf be b9 b8 bb ba ................ 1018 a5 a4 a7 a6 a1 a0 a3 a2 ad ac af ae a9 a8 50 cb ..............P. 1019 27 0c b7 '.. 1021 Decoded Data and CRC32K (537 bytes): 1022 78 d6 00 3a 3f 00 00 00 00 00 00 00 01 00 01 80 x..:?........... 1023 00 78 3f 2e e5 00 02 e4 db e8 55 3b a0 04 00 08 .x?.......U;.... 1024 09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 18 ................ 1025 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 ....... !"#$%&'( 1026 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 )*+,-./012345678 1027 39 3a 3b 3c 3d 3e 3f 40 41 42 43 44 45 46 47 48 9:;<=>?@ABCDEFGH 1028 49 4a 4b 4c 4d 4e 4f 50 51 52 53 54 55 56 57 58 IJKLMNOPQRSTUVWX 1029 59 5a 5b 5c 5d 5e 5f 60 61 62 63 64 65 66 67 68 YZ[\]^_`abcdefgh 1030 69 6a 6b 6c 6d 6e 6f 70 71 72 73 74 75 76 77 78 ijklmnopqrstuvwx 1031 79 7a 7b 7c 7d 7e 7f 80 81 82 83 84 85 86 87 88 yz{|}~.......... 1032 89 8a 8b 8c 8d 8e 8f 90 91 92 93 94 95 96 97 98 ................ 1033 99 9a 9b 9c 9d 9e 9f a0 a1 a2 a3 a4 a5 a6 a7 a8 ................ 1034 a9 aa ab ac ad ae af b0 b1 b2 b3 b4 b5 b6 b7 b8 ................ 1035 b9 ba bb bc bd be bf c0 c1 c2 c3 c4 c5 c6 c7 c8 ................ 1036 c9 ca cb cc cd ce cf d0 d1 d2 d3 d4 d5 d6 d7 d8 ................ 1037 d9 da db dc dd de df e0 e1 e2 e3 e4 e5 e6 e7 e8 ................ 1038 e9 ea eb ec ed ee ef f0 f1 f2 f3 f4 f5 f6 f7 f8 ................ 1039 f9 fa fb fc fd fe ff 00 01 02 03 04 05 06 07 08 ................ 1040 09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 18 ................ 1041 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 ....... !"#$%&'( 1042 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 )*+,-./012345678 1043 39 3a 3b 3c 3d 3e 3f 40 41 42 43 44 45 46 47 48 9:;<=>?@ABCDEFGH 1044 49 4a 4b 4c 4d 4e 4f 50 51 52 53 54 55 56 57 58 IJKLMNOPQRSTUVWX 1045 59 5a 5b 5c 5d 5e 5f 60 61 62 63 64 65 66 67 68 YZ[\]^_`abcdefgh 1046 69 6a 6b 6c 6d 6e 6f 70 71 72 73 74 75 76 77 78 ijklmnopqrstuvwx 1047 79 7a 7b 7c 7d 7e 7f 80 81 82 83 84 85 86 87 88 yz{|}~.......... 1048 89 8a 8b 8c 8d 8e 8f 90 91 92 93 94 95 96 97 98 ................ 1049 99 9a 9b 9c 9d 9e 9f a0 a1 a2 a3 a4 a5 a6 a7 a8 ................ 1050 a9 aa ab ac ad ae af b0 b1 b2 b3 b4 b5 b6 b7 b8 ................ 1051 b9 ba bb bc bd be bf c0 c1 c2 c3 c4 c5 c6 c7 c8 ................ 1052 c9 ca cb cc cd ce cf d0 d1 d2 d3 d4 d5 d6 d7 d8 ................ 1053 d9 da db dc dd de df e0 e1 e2 e3 e4 e5 e6 e7 e8 ................ 1054 e9 ea eb ec ed ee ef f0 f1 f2 f3 f4 f5 f6 f7 f8 ................ 1055 f9 fa fb fc fd 9e 72 59 e2 ......rY. 1057 Decompressed 6LoWPAN IPHC (558 bytes): 1058 60 00 00 00 02 06 3a 3f aa aa 00 00 00 00 00 00 `.....:?........ 1059 00 00 00 00 00 00 00 01 aa aa 00 00 00 00 00 00 ................ 1060 00 00 00 ff fe 00 00 01 80 00 78 3f 2e e5 00 02 ..........x?.... 1061 e4 db e8 55 3b a0 04 00 08 09 0a 0b 0c 0d 0e 0f ...U;........... 1062 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f ................ 1063 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f !"#$%&'()*+,-./ 1064 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 0123456789:;<=>? 1065 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO 1066 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f PQRSTUVWXYZ[\]^_ 1067 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f `abcdefghijklmno 1068 70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f pqrstuvwxyz{|}~. 1069 80 81 82 83 84 85 86 87 88 89 8a 8b 8c 8d 8e 8f ................ 1070 90 91 92 93 94 95 96 97 98 99 9a 9b 9c 9d 9e 9f ................ 1071 a0 a1 a2 a3 a4 a5 a6 a7 a8 a9 aa ab ac ad ae af ................ 1072 b0 b1 b2 b3 b4 b5 b6 b7 b8 b9 ba bb bc bd be bf ................ 1073 c0 c1 c2 c3 c4 c5 c6 c7 c8 c9 ca cb cc cd ce cf ................ 1074 d0 d1 d2 d3 d4 d5 d6 d7 d8 d9 da db dc dd de df ................ 1075 e0 e1 e2 e3 e4 e5 e6 e7 e8 e9 ea eb ec ed ee ef ................ 1076 f0 f1 f2 f3 f4 f5 f6 f7 f8 f9 fa fb fc fd fe ff ................ 1077 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f ................ 1078 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f ................ 1079 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f !"#$%&'()*+,-./ 1080 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 0123456789:;<=>? 1081 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO 1082 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f PQRSTUVWXYZ[\]^_ 1083 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f `abcdefghijklmno 1084 70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f pqrstuvwxyz{|}~. 1085 80 81 82 83 84 85 86 87 88 89 8a 8b 8c 8d 8e 8f ................ 1086 90 91 92 93 94 95 96 97 98 99 9a 9b 9c 9d 9e 9f ................ 1087 a0 a1 a2 a3 a4 a5 a6 a7 a8 a9 aa ab ac ad ae af ................ 1088 b0 b1 b2 b3 b4 b5 b6 b7 b8 b9 ba bb bc bd be bf ................ 1089 c0 c1 c2 c3 c4 c5 c6 c7 c8 c9 ca cb cc cd ce cf ................ 1090 d0 d1 d2 d3 d4 d5 d6 d7 d8 d9 da db dc dd de df ................ 1091 e0 e1 e2 e3 e4 e5 e6 e7 e8 e9 ea eb ec ed ee ef ................ 1092 f0 f1 f2 f3 f4 f5 f6 f7 f8 f9 fa fb fc fd .............. 1094 Authors' Addresses 1096 Kerry Lynn (editor) 1097 Verizon Labs 1098 50 Sylvan Rd 1099 Waltham , MA 02451 1100 USA 1102 Phone: +1 781 296 9722 1103 Email: kerlyn@ieee.org 1105 Jerry Martocci 1106 Johnson Controls, Inc. 1107 507 E. Michigan St 1108 Milwaukee , WI 53202 1109 USA 1111 Email: jpmartocci@sbcglobal.net 1113 Carl Neilson 1114 Delta Controls, Inc. 1115 17850 56th Ave 1116 Surrey , BC V3S 1C7 1117 Canada 1119 Phone: +1 604 575 5913 1120 Email: cneilson@deltacontrols.com 1122 Stuart Donaldson 1123 Honeywell Automation & Control Solutions 1124 6670 185th Ave NE 1125 Redmond , WA 98052 1126 USA 1128 Email: stuart.donaldson@honeywell.com