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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: December 18, 2016 Johnson Controls 6 C. Neilson 7 Delta Controls 8 S. Donaldson 9 Honeywell 10 June 16, 2016 12 Transmission of IPv6 over MS/TP Networks 13 draft-ietf-6lo-6lobac-05 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 December 18, 2016. 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 . . . . . . . . . . . . . . . 13 72 Appendix B. Consistent Overhead Byte Stuffing [COBS] . . . . . . 16 73 Appendix C. Encoded CRC-32K [CRC32K] . . . . . . . . . . . . . . 19 74 Appendix D. Example 6LoBAC Packet Decode . . . . . . . . . . . . 21 75 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26 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] 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 1.4. Goals and Constraints 224 The primary goal of this specification is to enable IPv6 directly on 225 wired end devices in building automation and control networks by 226 leveraging existing standards to the greatest extent possible. A 227 secondary goal is to co-exist with legacy MS/TP implementations. 228 Only the minimum changes necessary to support IPv6 over MS/TP were 229 specified in BACnet [Addendum_an] (see Section 1.3). 231 In order to co-exist with legacy devices, no changes are permitted to 232 the MS/TP addressing modes, frame header format, control frames, or 233 Master Node state machine as specified in BACnet [Clause9]. 235 2. MS/TP Mode for IPv6 237 ASHRAE has assigned an MS/TP Frame Type value of 34 to indicate IPv6 238 over MS/TP (LoBAC) Encapsulation. This falls within the range of 239 values that designate COBS-encoded data frames. 241 All MS/TP master nodes (including those that support IPv6) must 242 implement the Master Node state machine specified in BACnet [Clause9] 243 and handle Token, Poll For Master, and Reply to Poll For Master 244 control frames. MS/TP master nodes that support IPv6 must also 245 implement the Receive Frame state machine specified in [Clause9] as 246 extended by BACnet [Addendum_an]. 248 All MS/TP nodes that support IPv6 MUST support a data rate of 115,200 249 bit/s and MAY optionally support lower data rates as defined in 250 BACnet [Clause9]. 252 3. Addressing Modes 254 MS/TP node (MAC) addresses are one octet in length. The method of 255 assigning MAC addresses is outside the scope of this specification. 256 However, each MS/TP node on the link MUST have a unique address in 257 order to ensure correct MAC operation. 259 BACnet [Clause9] specifies that addresses 0 through 127 are valid for 260 master nodes. The method specified in Section 6 for creating a MAC- 261 layer-derived Interface Identifier (IID) ensures that an IID of all 262 zeros can never result. 264 A Destination Address of 255 (all nodes) indicates a MAC-layer 265 broadcast. MS/TP does not support multicast, therefore all IPv6 266 multicast packets SHOULD be broadcast at the MAC layer and filtered 267 at the IPv6 layer. A Source Address of 255 MUST NOT be used. 269 Hosts learn IPv6 prefixes via router advertisements according to 270 [RFC4861]. 272 4. Maximum Transmission Unit (MTU) 274 BACnet [Addendum_an] supports MSDUs up to 2032 octets in length. 275 This specification defines an MSDU length of at least 1280 octets and 276 at most 1500 octets (before encoding). This is sufficient to convey 277 the minimum MTU required by IPv6 [RFC2460] without the need for link- 278 layer fragmentation and reassembly. Support for an MSDU length of 279 1500 octets is RECOMMENDED. 281 5. LoBAC Adaptation Layer 283 The relatively low data rates of MS/TP indicate header compression as 284 a means to reduce latency. This section specifies an adaptation 285 layer to support compressed IPv6 headers and the compression format 286 is specified in Section 10. 288 Implementations MAY also support Generic Header Compression (GHC) 289 [RFC7400] for transport layer headers. A node implementing [RFC7400] 290 MUST probe its peers for GHC support before applying GHC. 292 The encapsulation format defined in this section (subsequently 293 referred to as the "LoBAC" encapsulation) comprises the MSDU of an 294 IPv6 over MS/TP frame. The LoBAC payload (i.e., an IPv6 packet) 295 follows an encapsulation header stack. LoBAC is a subset of the 296 LoWPAN encapsulation defined in [RFC4944] and extended by [RFC6282], 297 therefore the use of "LOWPAN" in literals below is intentional. The 298 primary difference between LoWPAN and LoBAC is omission of the Mesh, 299 Broadcast, Fragmentation, and LOWPAN_HC1 headers. 301 All LoBAC encapsulated datagrams transmitted over MS/TP are prefixed 302 by an encapsulation header stack consisting of a Dispatch value 303 followed by zero or more header fields. The only sequence currently 304 defined for LoBAC is the LOWPAN_IPHC header followed by payload, as 305 shown below: 307 +---------------+---------------+------...-----+ 308 | IPHC Dispatch | IPHC Header | Payload | 309 +---------------+---------------+------...-----+ 311 Figure 2: A LoBAC Encapsulated LOWPAN_IPHC Compressed IPv6 Datagram 313 The Dispatch value may be treated as an unstructured namespace. Only 314 a single pattern is used to represent current LoBAC functionality. 316 Pattern Header Type 317 +------------+-----------------------------------------------------+ 318 | 01 1xxxxx | LOWPAN_IPHC - LOWPAN_IPHC compressed IPv6 [RFC6282] | 319 +------------+-----------------------------------------------------+ 321 Figure 3: LoBAC Dispatch Value Bit Pattern 323 Other IANA-assigned 6LoWPAN Dispatch values do not apply to 6LoBAC 324 unless otherwise specified. 326 6. Stateless Address Autoconfiguration 328 This section defines how to obtain an IPv6 Interface Identifier. The 329 general procedure for creating a MAC-address-derived IID is described 330 in [RFC4291] Appendix A, "Creating Modified EUI-64 Format Interface 331 Identifiers", as updated by [RFC7136]. 333 The IID SHOULD NOT embed an [EUI-64] or any other globally unique 334 hardware identifier assigned to a device (see Section 12). 336 The Interface Identifier for link-local addresses SHOULD be formed by 337 concatenating a node's' 8-bit MS/TP MAC address to the seven octets 338 0x00, 0x00, 0x00, 0xFF, 0xFE, 0x00, 0x00. For example, an MS/TP MAC 339 address of hexadecimal value 0x4F results in the following IID: 341 |0 1|1 3|3 4|4 6| 342 |0 5|6 1|2 7|8 3| 343 +----------------+----------------+----------------+----------------+ 344 |0000000000000000|0000000011111111|1111111000000000|0000000001001111| 345 +----------------+----------------+----------------+----------------+ 347 This is the RECOMMENDED method of forming an IID for use in link- 348 local addresses, as it affords the most efficient header compression 349 provided by the LOWPAN_IPHC [RFC6282] format specified in Section 10. 351 A 64-bit privacy IID is RECOMMENDED for each forwardable address and 352 SHOULD be locally generated according to one of the methods cited in 353 Section 12. A node that generates a 64-bit privacy IID MUST register 354 it with its local router(s) by sending a Neighbor Solicitation (NS) 355 message with the Address Registration Option (ARO) and process 356 Neighbor Advertisements (NA) according to [RFC6775]. 358 An IPv6 address prefix used for stateless autoconfiguration [RFC4862] 359 of an MS/TP interface MUST have a length of 64 bits. 361 7. IPv6 Link Local Address 363 The IPv6 link-local address [RFC4291] for an MS/TP interface is 364 formed by appending the Interface Identifier, as defined above, to 365 the prefix FE80::/64. 367 10 bits 54 bits 64 bits 368 +----------+-----------------------+----------------------------+ 369 |1111111010| (zeros) | Interface Identifier | 370 +----------+-----------------------+----------------------------+ 372 8. Unicast Address Mapping 374 The address resolution procedure for mapping IPv6 non-multicast 375 addresses into MS/TP MAC-layer addresses follows the general 376 description in Section 7.2 of [RFC4861], unless otherwise specified. 378 The Source/Target Link-layer Address option has the following form 379 when the addresses are 8-bit MS/TP MAC-layer (node) addresses. 381 0 1 382 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 383 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 384 | Type | Length=1 | 385 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 386 | 0x00 | MS/TP Address | 387 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 388 | | 389 + Padding (all zeros) + 390 | | 391 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 393 Option fields: 395 Type: 397 1: for Source Link-layer address. 399 2: for Target Link-layer address. 401 Length: This is the length of this option (including the type and 402 length fields) in units of 8 octets. The value of this field is 1 403 for 8-bit MS/TP MAC addresses. 405 MS/TP Address: The 8-bit address in canonical bit order [RFC2469]. 406 This is the unicast address the interface currently responds to. 408 9. Multicast Address Mapping 410 All IPv6 multicast packets SHOULD be sent to MS/TP Destination 411 Address 255 (broadcast) and filtered at the IPv6 layer. When 412 represented as a 16-bit address in a compressed header (see 413 Section 10), it MUST be formed by padding on the left with a zero: 415 0 1 416 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 417 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 418 | 0x00 | 0xFF | 419 +-+-+-+-+-+-+-+-+---------------+ 421 10. Header Compression 423 LoBAC uses LOWPAN_IPHC IPv6 compression, which is specified in 424 [RFC6282] and included herein by reference. This section will simply 425 identify substitutions that should be made when interpreting the text 426 of [RFC6282]. 428 In general the following substitutions should be made: 430 - Replace instances of "6LoWPAN" with "MS/TP network" 432 - Replace instances of "IEEE 802.15.4 address" with "MS/TP address" 434 When a 16-bit address is called for (i.e., an IEEE 802.15.4 "short 435 address") it MUST be formed by padding the MS/TP address to the left 436 with a zero: 438 0 1 439 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 440 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 441 | 0x00 | MS/TP address | 442 +-+-+-+-+-+-+-+-+---------------+ 444 If LOWPAN_IPHC compression [RFC6282] is used with context, the 445 router(s) directly attached to the MS/TP segment MUST disseminate the 446 6LoWPAN Context Option (6CO) according to [RFC6775], Section 7.2. 448 11. IANA Considerations 450 This document uses values previously reserved by [RFC4944] and 451 [RFC6282] and makes no further requests of IANA. 453 Note to RFC Editor: this section may be removed upon publication. 455 12. Security Considerations 457 Forwardable addresses that contain IIDs generated using MS/TP node 458 addresses may expose a network to address scanning attacks. For this 459 reason, it is RECOMMENDED that a different (but stable) IID be 460 generated for each forwardable address in use according to, for 461 example, [RFC3315], [RFC3972], [RFC4941], [RFC5535], or [RFC7217]. 463 MS/TP networks are by definition wired and not susceptible to casual 464 eavesdropping. By the same token, MS/TP nodes are stationary and 465 correlation of activities or location tracking of individuals is 466 unlikely. 468 13. Acknowledgments 470 We are grateful to the authors of [RFC4944] and members of the IETF 471 6LoWPAN working group; this document borrows liberally from their 472 work. Ralph Droms and Brian Haberman provided indispensable guidance 473 and support from the outset. Peter van der Stok, James Woodyatt, and 474 Carsten Bormann provided detailed reviews. Stuart Cheshire invented 475 the very clever COBS encoding. Michael Osborne made the critical 476 observation that separately encoding the data and CRC32K fields would 477 allow the CRC to be calculated on-the-fly. Alexandru Petrescu, Brian 478 Frank, Geoff Mulligan, and Don Sturek offered valuable comments. 480 14. References 482 14.1. Normative References 484 [Addendum_an] 485 ASHRAE, "ANSI/ASHRAE Addenda an, at, au, av, aw, ax, and 486 az to ANSI/ASHRAE Standard 135-2012, BACnet - A Data 487 Communication Protocol for Building Automation and Control 488 Networks", July 2014, 489 . 492 [Clause9] American Society of Heating, Refrigerating, and Air- 493 Conditioning Engineers, "BACnet - A Data Communication 494 Protocol for Building Automation and Control Networks", 495 ANSI/ASHRAE 135-2012 (Clause 9), March 2013. 497 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 498 Requirement Levels", BCP 14, RFC 2119, 499 DOI 10.17487/RFC2119, March 1997, 500 . 502 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 503 (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460, 504 December 1998, . 506 [RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins, 507 C., and M. Carney, "Dynamic Host Configuration Protocol 508 for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July 509 2003, . 511 [RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)", 512 RFC 3972, DOI 10.17487/RFC3972, March 2005, 513 . 515 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 516 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 517 2006, . 519 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 520 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 521 DOI 10.17487/RFC4861, September 2007, 522 . 524 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 525 Address Autoconfiguration", RFC 4862, 526 DOI 10.17487/RFC4862, September 2007, 527 . 529 [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy 530 Extensions for Stateless Address Autoconfiguration in 531 IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007, 532 . 534 [RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, 535 "Transmission of IPv6 Packets over IEEE 802.15.4 536 Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007, 537 . 539 [RFC5535] Bagnulo, M., "Hash-Based Addresses (HBA)", RFC 5535, 540 DOI 10.17487/RFC5535, June 2009, 541 . 543 [RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6 544 Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, 545 DOI 10.17487/RFC6282, September 2011, 546 . 548 [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. 549 Bormann, "Neighbor Discovery Optimization for IPv6 over 550 Low-Power Wireless Personal Area Networks (6LoWPANs)", 551 RFC 6775, DOI 10.17487/RFC6775, November 2012, 552 . 554 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 555 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 556 February 2014, . 558 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 559 Interface Identifiers with IPv6 Stateless Address 560 Autoconfiguration (SLAAC)", RFC 7217, 561 DOI 10.17487/RFC7217, April 2014, 562 . 564 [RFC7400] Bormann, C., "6LoWPAN-GHC: Generic Header Compression for 565 IPv6 over Low-Power Wireless Personal Area Networks 566 (6LoWPANs)", RFC 7400, DOI 10.17487/RFC7400, November 567 2014, . 569 14.2. Informative References 571 [COBS] Cheshire, S. and M. Baker, "Consistent Overhead Byte 572 Stuffing", IEEE/ACM TRANSACTIONS ON NETWORKING, VOL.7, 573 NO.2 , April 1999, 574 . 576 [CRC32K] Koopman, P., "32-Bit Cyclic Redundancy Codes for Internet 577 Applications", IEEE/IFIP International Conference on 578 Dependable Systems and Networks (DSN 2002) , June 2002, 579 . 582 [EUI-64] IEEE, "Guidelines for 64-bit Global Identifier (EUI-64) 583 Registration Authority", March 1997, 584 . 587 [IEEE.802.3] 588 "Information technology - Telecommunications and 589 information exchange between systems - Local and 590 metropolitan area networks - Specific requirements - Part 591 3: Carrier Sense Multiple Access with Collision Detection 592 (CMSA/CD) Access Method and Physical Layer 593 Specifications", IEEE Std 802.3-2012, December 2012, 594 . 596 [RFC2469] Narten, T. and C. Burton, "A Caution On The Canonical 597 Ordering Of Link-Layer Addresses", RFC 2469, 598 DOI 10.17487/RFC2469, December 1998, 599 . 601 [TIA-485-A] 602 Telecommunications Industry Association, "TIA-485-A, 603 Electrical Characteristics of Generators and Receivers for 604 Use in Balanced Digital Multipoint Systems (ANSI/TIA/EIA- 605 485-A-98) (R2003)", March 2003. 607 Appendix A. Abstract MAC Interface 609 This Appendix is informative and not part of the standard. 611 BACnet [Clause9] provides support for MAC-layer clients through its 612 SendFrame and ReceivedDataNoReply procedures. However, it does not 613 define a network-protocol independent abstract interface for the MAC. 614 This is provided below as an aid to implementation. 616 A.1. MA-DATA.request 618 A.1.1. Function 620 This primitive defines the transfer of data from a MAC client entity 621 to a single peer entity or multiple peer entities in the case of a 622 broadcast address. 624 A.1.2. Semantics of the Service Primitive 626 The semantics of the primitive are as follows: 628 MA-DATA.request ( 629 destination_address, 630 source_address, 631 data, 632 type 633 ) 635 The 'destination_address' parameter may specify either an individual 636 or a broadcast MAC entity address. It must contain sufficient 637 information to create the Destination Address field (see Section 1.3) 638 that is prepended to the frame by the local MAC sublayer entity. The 639 'source_address' parameter, if present, must specify an individual 640 MAC address. If the source_address parameter is omitted, the local 641 MAC sublayer entity will insert a value associated with that entity. 643 The 'data' parameter specifies the MAC service data unit (MSDU) to be 644 transferred by the MAC sublayer entity. There is sufficient 645 information associated with the MSDU for the MAC sublayer entity to 646 determine the length of the data unit. 648 The 'type' parameter specifies the value of the MS/TP Frame Type 649 field that is prepended to the frame by the local MAC sublayer 650 entity. 652 A.1.3. When Generated 654 This primitive is generated by the MAC client entity whenever data 655 shall be transferred to a peer entity or entities. This can be in 656 response to a request from higher protocol layers or from data 657 generated internally to the MAC client, such as a Token frame. 659 A.1.4. Effect on Receipt 661 Receipt of this primitive will cause the MAC entity to insert all MAC 662 specific fields, including Destination Address, Source Address, Frame 663 Type, and any fields that are unique to the particular media access 664 method, and pass the properly formed frame to the lower protocol 665 layers for transfer to the peer MAC sublayer entity or entities. 667 A.2. MA-DATA.indication 669 A.2.1. Function 671 This primitive defines the transfer of data from the MAC sublayer 672 entity to the MAC client entity or entities in the case of a 673 broadcast address. 675 A.2.2. Semantics of the Service Primitive 677 The semantics of the primitive are as follows: 679 MA-DATA.indication ( 680 destination_address, 681 source_address, 682 data, 683 type 684 ) 686 The 'destination_address' parameter may be either an individual or a 687 broadcast address as specified by the Destination Address field of 688 the incoming frame. The 'source_address' parameter is an individual 689 address as specified by the Source Address field of the incoming 690 frame. 692 The 'data' parameter specifies the MAC service data unit (MSDU) as 693 received by the local MAC entity. There is sufficient information 694 associated with the MSDU for the MAC sublayer client to determine the 695 length of the data unit. 697 The 'type' parameter is the value of the MS/TP Frame Type field of 698 the incoming frame. 700 A.2.3. When Generated 702 The MA_DATA.indication is passed from the MAC sublayer entity to the 703 MAC client entity or entities to indicate the arrival of a frame to 704 the local MAC sublayer entity that is destined for the MAC client. 705 Such frames are reported only if they are validly formed, received 706 without error, and their destination address designates the local MAC 707 entity. Frames destined for the MAC Control sublayer are not passed 708 to the MAC client. 710 A.2.4. Effect on Receipt 712 The effect of receipt of this primitive by the MAC client is 713 unspecified. 715 Appendix B. Consistent Overhead Byte Stuffing [COBS] 717 This Appendix is informative and not part of the standard. 719 BACnet [Addendum_an] corrects a long-standing issue with the MS/TP 720 specification; namely that preamble sequences were not escaped 721 whenever they appeared in the Data or Data CRC fields. In rare 722 cases, this resulted in dropped frames due to loss of frame 723 synchronization. The solution is to encode the Data and 32-bit Data 724 CRC fields before transmission using Consistent Overhead Byte 725 Stuffing [COBS] and decode these fields upon reception. 727 COBS is a run-length encoding method that nominally removes '0x00' 728 octets from its input. Any selected octet value may be removed by 729 XOR'ing that value with each octet of the COBS output. BACnet 730 [Addendum_an] specifies the preamble octet '0x55' for removal. 732 The minimum overhead of COBS is one octet per encoded field. The 733 worst-case overhead in long fields is bounded to one octet per 254, 734 or less than 0.4%, as described in [COBS]. 736 Frame encoding proceeds logically in two passes. The Encoded Data 737 field is prepared by passing the MSDU through the COBS encoder and 738 XOR'ing the preamble octet '0x55' with each octet of the output. The 739 Encoded CRC-32K field is then prepared by calculating a CRC-32K over 740 the Encoded Data field and formatting it for transmission as 741 described in Appendix C. The combined length of these fields, minus 742 two octets for compatibility with existing MS/TP devices, is placed 743 in the MS/TP header Length field before transmission. 745 Example COBS encoder and decoder functions are shown below for 746 illustration. Complete examples of use and test vectors are provided 747 in BACnet [Addendum_an]. 749 #include 750 #include 752 /* 753 * Encodes 'length' octets of data located at 'from' and 754 * writes one or more COBS code blocks at 'to', removing any 755 * 'mask' octets that may present be in the encoded data. 756 * Returns the length of the encoded data. 757 */ 759 size_t 760 cobs_encode (uint8_t *to, const uint8_t *from, size_t length, 761 uint8_t mask) 762 { 763 size_t code_index = 0; 764 size_t read_index = 0; 765 size_t write_index = 1; 766 uint8_t code = 1; 767 uint8_t data, last_code; 769 while (read_index < length) { 770 data = from[read_index++]; 771 /* 772 * In the case of encountering a non-zero octet in the data, 773 * simply copy input to output and increment the code octet. 774 */ 775 if (data != 0) { 776 to[write_index++] = data ^ mask; 777 code++; 778 if (code != 255) 779 continue; 780 } 781 /* 782 * In the case of encountering a zero in the data or having 783 * copied the maximum number (254) of non-zero octets, store 784 * the code octet and reset the encoder state variables. 785 */ 786 last_code = code; 787 to[code_index] = code ^ mask; 788 code_index = write_index++; 789 code = 1; 790 } 791 /* 792 * If the last chunk contains exactly 254 non-zero octets, then 793 * this exception is handled above (and returned length must be 794 * adjusted). Otherwise, encode the last chunk normally, as if 795 * a "phantom zero" is appended to the data. 796 */ 797 if ((last_code == 255) && (code == 1)) 798 write_index--; 799 else 800 to[code_index] = code ^ mask; 802 return write_index; 804 } 806 #include 807 #include 809 /* 810 * Decodes 'length' octets of data located at 'from' and 811 * writes the original client data at 'to', restoring any 812 * 'mask' octets that may present in the encoded data. 813 * Returns the length of the encoded data or zero if error. 814 */ 815 size_t 816 cobs_decode (uint8_t *to, const uint8_t *from, size_t length, 817 uint8_t mask) 818 { 819 size_t read_index = 0; 820 size_t write_index = 0; 821 uint8_t code, last_code; 823 while (read_index < length) { 824 code = from[read_index] ^ mask; 825 last_code = code; 826 /* 827 * Sanity check the encoding to prevent the while() loop below 828 * from overrunning the output buffer. 829 */ 830 if (read_index + code > length) 831 return 0; 833 read_index++; 834 while (--code > 0) 835 to[write_index++] = from[read_index++] ^ mask; 836 /* 837 * Restore the implicit zero at the end of each decoded block 838 * except when it contains exactly 254 non-zero octets or the 839 * end of data has been reached. 840 */ 841 if ((last_code != 255) && (read_index < length)) 842 to[write_index++] = 0; 843 } 844 return write_index; 845 } 847 Appendix C. Encoded CRC-32K [CRC32K] 849 This Appendix is informative and not part of the standard. 851 Extending the payload of MS/TP to 1500 octets required upgrading the 852 Data CRC from 16 bits to 32 bits. P.Koopman has authored several 853 papers on evaluating CRC polynomials for network applications. In 854 [CRC32K], he surveyed the entire 32-bit polynomial space and noted 855 some that exceed the [IEEE.802.3] polynomial in performance. BACnet 856 [Addendum_an] specifies the CRC-32K (Koopman) polynomial. 858 The specified use of the calc_crc32K() function is as follows. 859 Before a frame is transmitted, 'crc_value' is initialized to all 860 ones. After passing each octet of the [COBS] Encoded Data through 861 the function, the ones complement of the resulting 'crc_value' is 862 arranged in LSB-first order and is itself [COBS] encoded. The length 863 of the resulting Encoded CRC-32K field is always five octets. 865 Upon reception of a frame, 'crc_value' is initialized to all ones. 866 The octets of the Encoded Data field are accumulated by the 867 calc_crc32K() function before decoding. The Encoded CRC-32K field is 868 then decoded and the resulting four octets are accumulated by the 869 calc_crc32K() function. If the result is the expected residue value 870 'CRC32K_RESIDUE', then the frame was received correctly. 872 An example CRC-32K function in shown below for illustration. 873 Complete examples of use and test vectors are provided in BACnet 874 [Addendum_an]. 876 #include 878 /* See BACnet Addendum 135-2012an, section G.3.2 */ 879 #define CRC32K_INITIAL_VALUE (0xFFFFFFFF) 880 #define CRC32K_RESIDUE (0x0843323B) 882 /* CRC-32K polynomial, 1 + x**1 + ... + x**30 (+ x**32) */ 883 #define CRC32K_POLY (0xEB31D82E) 885 /* 886 * Accumulate 'data_value' into the CRC in 'crc_value'. 887 * Return updated CRC. 888 * 889 * Note: crc_value must be set to CRC32K_INITIAL_VALUE 890 * before initial call. 891 */ 892 uint32_t 893 calc_crc32K (uint8_t data_value, uint32_t crc_value) 894 { 895 int b; 897 for (b = 0; b < 8; b++) { 898 if ((data_value & 1) ^ (crc_value & 1)) { 899 crc_value >>= 1; 900 crc_value ^= CRC32K_POLY; 901 } else { 902 crc_value >>= 1; 903 } 904 data_value >>= 1; 905 } 906 return crc_value; 907 } 909 Appendix D. Example 6LoBAC Packet Decode 911 This Appendix is informative and not part of the standard. 913 BACnet MS/TP, Src (2), Dst (1), IPv6 Encapsulation 914 Preamble 55: 0x55 915 Preamble FF: 0xff 916 Frame Type: IPv6 Encapsulation (34) 917 Destination Address: 1 918 Source Address: 2 919 Length: 537 920 Header CRC: 0x1c [correct] 921 Extended Data CRC: 0x9e7259e2 [correct] 922 6LoWPAN 923 IPHC Header 924 011. .... = Pattern: IP header compression (0x03) 925 ...1 1... .... .... = Traffic class and flow label: 926 Version, traffic class, and flow label 927 compressed (0x0003) 928 .... .0.. .... .... = Next header: Inline 929 .... ..00 .... .... = Hop limit: Inline (0x0000) 930 .... .... 1... .... = Context identifier extension: True 931 .... .... .1.. .... = Source address compression: Stateful 932 .... .... ..01 .... = Source address mode: 933 64-bits inline (0x0001) 934 .... .... .... 0... = Multicast address compression: False 935 .... .... .... .1.. = Destination address compression: 936 Stateful 937 .... .... .... ..10 = Destination address mode: 938 16-bits inline (0x0002) 939 0000 .... = Source context identifier: 0x00 940 .... 0000 = Destination context identifier: 0x00 941 [Source context: aaaa:: (aaaa::)] 942 [Destination context: aaaa:: (aaaa::)] 943 Next header: ICMPv6 (0x3a) 944 Hop limit: 63 945 Source: aaaa::1 (aaaa::1) 946 Destination: aaaa::ff:fe00:1 (aaaa::ff:fe00:1) 947 Internet Protocol Version 6, Src: aaaa::1 (aaaa::1), 948 Dst: aaaa::ff:fe00:1 (aaaa::ff:fe00:1) 949 0110 .... .... .... .... .... .... .... = Version: 6 950 .... 0000 0000 .... .... .... .... .... = Traffic class: 951 0x00000000 952 .... 0000 00.. .... .... .... .... .... = Differentiated 953 Services Field: 954 Default (0x00000000) 955 .... .... ..0. .... .... .... .... .... = ECN-Capable Transport 956 (ECT): Not set 957 .... .... ...0 .... .... .... .... .... = ECN-CE: Not set 958 .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000 959 Payload length: 518 960 Next header: ICMPv6 (58) 961 Hop limit: 63 962 Source: aaaa::1 (aaaa::1) 963 Destination: aaaa::ff:fe00:1 (aaaa::ff:fe00:1) 964 Internet Control Message Protocol v6 965 Type: Echo (ping) request (128) 966 Code: 0 967 Checksum: 0x783f [correct] 968 Identifier: 0x2ee5 969 Sequence: 2 970 [Response In: 5165] 971 Data (510 bytes) 972 Data: e4dbe8553ba0040008090a0b0c0d0e0f1011121314151617... 973 [Length: 510] 975 Frame (547 bytes): 976 55 ff 22 01 02 02 19 1c 56 2d 83 56 6f 6a 54 54 U.".....V-.VojTT 977 54 54 54 54 57 54 56 54 d5 50 2d 6a 7b b0 5c 57 TTTTWTVT.P-j{.\W 978 b1 8e bd 00 6e f5 51 ac 5d 5c 5f 5e 59 58 5b 5a ....n.Q.]\_^YX[Z 979 45 44 47 46 41 40 43 42 4d 4c 4f 4e 49 48 4b 4a EDGFA@CBMLONIHKJ 980 75 74 77 76 71 70 73 72 7d 7c 7f 7e 79 78 7b 7a utwvqpsr}|.~yx{z 981 65 64 67 66 61 60 63 62 6d 6c 6f 6e 69 68 6b 6a edgfa`cbmlonihkj 982 15 14 17 16 11 10 13 12 1d 1c 1f 1e 19 18 1b 1a ................ 983 05 04 07 06 01 00 03 02 0d 0c 0f 0e 09 08 0b 0a ................ 984 35 34 37 36 31 30 33 32 3d 3c 3f 3e 39 38 3b 3a 54761032=98;: 985 25 24 27 26 21 20 23 22 2d 2c 2f 2e 29 28 2b 2a %$'&! #"-,/.)(+* 986 d5 d4 d7 d6 d1 d0 d3 d2 dd dc df de d9 d8 db da ................ 987 c5 c4 c7 c6 c1 c0 c3 c2 cd cc cf ce c9 c8 cb ca ................ 988 f5 f4 f7 f6 f1 f0 f3 f2 fd fc ff fe f9 f8 fb fa ................ 989 e5 e4 e7 e6 e1 e0 e3 e2 ed ec ef ee e9 e8 eb ea ................ 990 95 94 97 96 91 90 93 92 9d 9c 9f 9e 99 98 9b 9a ................ 991 85 84 87 86 81 80 83 82 8d 8c 8f 8e 89 88 8b 8a ................ 992 b5 b4 b7 b6 b1 b0 b3 b2 bd bc bf be b9 b8 bb ba ................ 993 a5 a4 a7 a6 a1 a0 a3 a2 ad ac af ae a9 a8 ab aa ................ 994 ab 54 57 56 51 50 53 52 5d 5c 5f 5e 59 58 5b 5a .TWVQPSR]\_^YX[Z 995 45 44 47 46 41 40 43 42 4d 4c 4f 4e 49 48 4b 4a EDGFA@CBMLONIHKJ 996 75 74 77 76 71 70 73 72 7d 7c 7f 7e 79 78 7b 7a utwvqpsr}|.~yx{z 997 65 64 67 66 61 60 63 62 6d 6c 6f 6e 69 68 6b 6a edgfa`cbmlonihkj 998 15 14 17 16 11 10 13 12 1d 1c 1f 1e 19 18 1b 1a ................ 999 05 04 07 06 01 00 03 02 0d 0c 0f 0e 09 08 0b 0a ................ 1000 35 34 37 36 31 30 33 32 3d 3c 3f 3e 39 38 3b 3a 54761032=98;: 1001 25 24 27 26 21 20 23 22 2d 2c 2f 2e 29 28 2b 2a %$'&! #"-,/.)(+* 1002 d5 d4 d7 d6 d1 d0 d3 d2 dd dc df de d9 d8 db da ................ 1003 c5 c4 c7 c6 c1 c0 c3 c2 cd cc cf ce c9 c8 cb ca ................ 1004 f5 f4 f7 f6 f1 f0 f3 f2 fd fc ff fe f9 f8 fb fa ................ 1005 e5 e4 e7 e6 e1 e0 e3 e2 ed ec ef ee e9 e8 eb ea ................ 1006 95 94 97 96 91 90 93 92 9d 9c 9f 9e 99 98 9b 9a ................ 1007 85 84 87 86 81 80 83 82 8d 8c 8f 8e 89 88 8b 8a ................ 1008 b5 b4 b7 b6 b1 b0 b3 b2 bd bc bf be b9 b8 bb ba ................ 1009 a5 a4 a7 a6 a1 a0 a3 a2 ad ac af ae a9 a8 50 cb ..............P. 1010 27 0c b7 '.. 1012 Decoded Data and CRC32K (537 bytes): 1013 78 d6 00 3a 3f 00 00 00 00 00 00 00 01 00 01 80 x..:?........... 1014 00 78 3f 2e e5 00 02 e4 db e8 55 3b a0 04 00 08 .x?.......U;.... 1015 09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 18 ................ 1016 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 ....... !"#$%&'( 1017 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 )*+,-./012345678 1018 39 3a 3b 3c 3d 3e 3f 40 41 42 43 44 45 46 47 48 9:;<=>?@ABCDEFGH 1019 49 4a 4b 4c 4d 4e 4f 50 51 52 53 54 55 56 57 58 IJKLMNOPQRSTUVWX 1020 59 5a 5b 5c 5d 5e 5f 60 61 62 63 64 65 66 67 68 YZ[\]^_`abcdefgh 1021 69 6a 6b 6c 6d 6e 6f 70 71 72 73 74 75 76 77 78 ijklmnopqrstuvwx 1022 79 7a 7b 7c 7d 7e 7f 80 81 82 83 84 85 86 87 88 yz{|}~.......... 1023 89 8a 8b 8c 8d 8e 8f 90 91 92 93 94 95 96 97 98 ................ 1024 99 9a 9b 9c 9d 9e 9f a0 a1 a2 a3 a4 a5 a6 a7 a8 ................ 1025 a9 aa ab ac ad ae af b0 b1 b2 b3 b4 b5 b6 b7 b8 ................ 1026 b9 ba bb bc bd be bf c0 c1 c2 c3 c4 c5 c6 c7 c8 ................ 1027 c9 ca cb cc cd ce cf d0 d1 d2 d3 d4 d5 d6 d7 d8 ................ 1028 d9 da db dc dd de df e0 e1 e2 e3 e4 e5 e6 e7 e8 ................ 1029 e9 ea eb ec ed ee ef f0 f1 f2 f3 f4 f5 f6 f7 f8 ................ 1030 f9 fa fb fc fd fe ff 00 01 02 03 04 05 06 07 08 ................ 1031 09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 18 ................ 1032 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 ....... !"#$%&'( 1033 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 )*+,-./012345678 1034 39 3a 3b 3c 3d 3e 3f 40 41 42 43 44 45 46 47 48 9:;<=>?@ABCDEFGH 1035 49 4a 4b 4c 4d 4e 4f 50 51 52 53 54 55 56 57 58 IJKLMNOPQRSTUVWX 1036 59 5a 5b 5c 5d 5e 5f 60 61 62 63 64 65 66 67 68 YZ[\]^_`abcdefgh 1037 69 6a 6b 6c 6d 6e 6f 70 71 72 73 74 75 76 77 78 ijklmnopqrstuvwx 1038 79 7a 7b 7c 7d 7e 7f 80 81 82 83 84 85 86 87 88 yz{|}~.......... 1039 89 8a 8b 8c 8d 8e 8f 90 91 92 93 94 95 96 97 98 ................ 1040 99 9a 9b 9c 9d 9e 9f a0 a1 a2 a3 a4 a5 a6 a7 a8 ................ 1041 a9 aa ab ac ad ae af b0 b1 b2 b3 b4 b5 b6 b7 b8 ................ 1042 b9 ba bb bc bd be bf c0 c1 c2 c3 c4 c5 c6 c7 c8 ................ 1043 c9 ca cb cc cd ce cf d0 d1 d2 d3 d4 d5 d6 d7 d8 ................ 1044 d9 da db dc dd de df e0 e1 e2 e3 e4 e5 e6 e7 e8 ................ 1045 e9 ea eb ec ed ee ef f0 f1 f2 f3 f4 f5 f6 f7 f8 ................ 1046 f9 fa fb fc fd 9e 72 59 e2 ......rY. 1048 Decompressed 6LoWPAN IPHC (558 bytes): 1049 60 00 00 00 02 06 3a 3f aa aa 00 00 00 00 00 00 `.....:?........ 1050 00 00 00 00 00 00 00 01 aa aa 00 00 00 00 00 00 ................ 1051 00 00 00 ff fe 00 00 01 80 00 78 3f 2e e5 00 02 ..........x?.... 1052 e4 db e8 55 3b a0 04 00 08 09 0a 0b 0c 0d 0e 0f ...U;........... 1053 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f ................ 1054 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f !"#$%&'()*+,-./ 1055 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 0123456789:;<=>? 1056 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO 1057 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f PQRSTUVWXYZ[\]^_ 1058 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f `abcdefghijklmno 1059 70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f pqrstuvwxyz{|}~. 1060 80 81 82 83 84 85 86 87 88 89 8a 8b 8c 8d 8e 8f ................ 1061 90 91 92 93 94 95 96 97 98 99 9a 9b 9c 9d 9e 9f ................ 1062 a0 a1 a2 a3 a4 a5 a6 a7 a8 a9 aa ab ac ad ae af ................ 1063 b0 b1 b2 b3 b4 b5 b6 b7 b8 b9 ba bb bc bd be bf ................ 1064 c0 c1 c2 c3 c4 c5 c6 c7 c8 c9 ca cb cc cd ce cf ................ 1065 d0 d1 d2 d3 d4 d5 d6 d7 d8 d9 da db dc dd de df ................ 1066 e0 e1 e2 e3 e4 e5 e6 e7 e8 e9 ea eb ec ed ee ef ................ 1067 f0 f1 f2 f3 f4 f5 f6 f7 f8 f9 fa fb fc fd fe ff ................ 1068 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f ................ 1069 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f ................ 1070 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f !"#$%&'()*+,-./ 1071 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 0123456789:;<=>? 1072 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO 1073 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f PQRSTUVWXYZ[\]^_ 1074 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f `abcdefghijklmno 1075 70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f pqrstuvwxyz{|}~. 1076 80 81 82 83 84 85 86 87 88 89 8a 8b 8c 8d 8e 8f ................ 1077 90 91 92 93 94 95 96 97 98 99 9a 9b 9c 9d 9e 9f ................ 1078 a0 a1 a2 a3 a4 a5 a6 a7 a8 a9 aa ab ac ad ae af ................ 1079 b0 b1 b2 b3 b4 b5 b6 b7 b8 b9 ba bb bc bd be bf ................ 1080 c0 c1 c2 c3 c4 c5 c6 c7 c8 c9 ca cb cc cd ce cf ................ 1081 d0 d1 d2 d3 d4 d5 d6 d7 d8 d9 da db dc dd de df ................ 1082 e0 e1 e2 e3 e4 e5 e6 e7 e8 e9 ea eb ec ed ee ef ................ 1083 f0 f1 f2 f3 f4 f5 f6 f7 f8 f9 fa fb fc fd .............. 1085 Authors' Addresses 1087 Kerry Lynn (editor) 1088 Verizon Labs 1089 50 Sylvan Rd 1090 Waltham , MA 02451 1091 USA 1093 Phone: +1 781 296 9722 1094 Email: kerlyn@ieee.org 1096 Jerry Martocci 1097 Johnson Controls, Inc. 1098 507 E. Michigan St 1099 Milwaukee , WI 53202 1100 USA 1102 Phone: +1 414 524 4010 1103 Email: jerald.p.martocci@jci.com 1105 Carl Neilson 1106 Delta Controls, Inc. 1107 17850 56th Ave 1108 Surrey , BC V3S 1C7 1109 Canada 1111 Phone: +1 604 575 5913 1112 Email: cneilson@deltacontrols.com 1114 Stuart Donaldson 1115 Honeywell Automation & Control Solutions 1116 6670 185th Ave NE 1117 Redmond , WA 98052 1118 USA 1120 Email: stuart.donaldson@honeywell.com