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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. 'BACnet' ** 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 (==), 2 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: August 31, 2017 Johnson Controls 6 C. Neilson 7 Delta Controls 8 S. Donaldson 9 Honeywell 10 February 27, 2017 12 Transmission of IPv6 over MS/TP Networks 13 draft-ietf-6lo-6lobac-07 15 Abstract 17 Master-Slave/Token-Passing (MS/TP) is a medium access control method 18 for the RS-485 physical layer and is used primarily 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 August 31, 2017. 40 Copyright Notice 42 Copyright (c) 2017 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. Profile for IPv6 over MS/TP . . . . . . . . . . . . . . . . . 5 59 3. Addressing Modes . . . . . . . . . . . . . . . . . . . . . . 6 60 4. Maximum Transmission Unit (MTU) . . . . . . . . . . . . . . . 7 61 5. LoBAC Adaptation Layer . . . . . . . . . . . . . . . . . . . 7 62 6. Stateless Address Autoconfiguration . . . . . . . . . . . . . 8 63 7. IPv6 Link Local Address . . . . . . . . . . . . . . . . . . . 9 64 8. Unicast Address Mapping . . . . . . . . . . . . . . . . . . . 9 65 9. Multicast Address Mapping . . . . . . . . . . . . . . . . . . 10 66 10. Header Compression . . . . . . . . . . . . . . . . . . . . . 10 67 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 68 12. Security Considerations . . . . . . . . . . . . . . . . . . . 11 69 13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11 70 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 71 Appendix A. Abstract MAC Interface . . . . . . . . . . . . . . . 14 72 Appendix B. Consistent Overhead Byte Stuffing [COBS] . . . . . . 17 73 Appendix C. Encoded CRC-32K [CRC32K] . . . . . . . . . . . . . . 20 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 and is used 81 primarily 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 where noted, elements of the 6LoWPAN specifications [RFC4944], 86 [RFC6282], and [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. These constraints, together 90 with low data rates and a small MAC address space, are similar to 91 those faced in 6LoWPAN networks. MS/TP differs significantly from 92 6LoWPAN in at least three respects: a) MS/TP devices are typically 93 mains powered, b) all MS/TP devices on a segment can communicate 94 directly so there are no hidden node or mesh routing issues, and c) 95 the latest MS/TP specification provides support for large payloads, 96 eliminating the need for fragmentation and reassembly below IPv6. 98 The following sections provide a brief overview of MS/TP, then 99 describe how to form IPv6 addresses and encapsulate IPv6 packets in 100 MS/TP frames. The encapsulation (subsequently referred to as 101 "LoBAC") supports a REQUIRED header compression mechanism that is 102 based on LOWPAN_IPHC [RFC6282] and improves MS/TP link utilization. 104 1.1. Requirements Language 106 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 107 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 108 document are to be interpreted as described in [RFC2119]. 110 1.2. Abbreviations Used 112 ASHRAE: American Society of Heating, Refrigerating, and Air- 113 Conditioning Engineers (http://www.ashrae.org) 115 BACnet: An ISO/ANSI/ASHRAE Standard Data Communication Protocol 116 for Building Automation and Control Networks 118 CRC: Cyclic Redundancy Code 120 MAC: Medium Access Control 122 MSDU: MAC Service Data Unit (MAC client data) 124 MTU: Maximum Transmission Unit; the size of the largest network 125 layer protocol data unit that can be communicated in a single 126 network transaction 128 UART: Universal Asynchronous Transmitter/Receiver 130 1.3. MS/TP Overview 132 This section provides a brief overview of MS/TP, as specified in 133 ANSI/ASHRAE Std 135-2016 [BACnet] Clause 9. This version of [BACnet] 134 Clause 9 incorporates changes to legacy MS/TP, introduced in ANSI/ 135 ASHRAE Addendum an to ANSI/ASHRAE Std 135-2012 [Addendum_an], that 136 support larger frame sizes and improved error handling. [BACnet] 137 Clause 9 also covers physical layer deployment options. 139 MS/TP is designed to enable multidrop networks over shielded twisted 140 pair wiring. It can support network segments up to 1000 meters in 141 length at a data rate of 115,200 bit/s, or segments up to 1200 meters 142 in length at lower bit rates. An MS/TP link requires only a UART, an 143 RS-485 [TIA-485-A] transceiver with a driver that can be disabled, 144 and a 5 ms resolution timer. The MS/TP MAC is typically implemented 145 in software. 147 The differential signaling used by [TIA-485-A] requires a contention- 148 free MAC. MS/TP uses a token to control access to a multidrop bus. 149 A master node may only initiate the transmission of a data frame when 150 it holds the token. After sending at most a configured maximum 151 number of data frames, a master node passes the token to the next 152 master node (as determined by MAC address). If present on the link, 153 legacy MS/TP implementations (including any slave nodes) ignore the 154 frame format defined in this specification. 156 [BACnet] Clause 9 defines a range of Frame Type values used to 157 designate frames that contain data and data CRC fields encoded using 158 Consistent Overhead Byte Stuffing [COBS] (see Appendix B). The 159 purpose of COBS encoding is to eliminate preamble sequences from the 160 Encoded Data and Encoded CRC-32K fields. The Encoded Data is covered 161 by a 32-bit CRC [CRC32K] (see Appendix C) which is also 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 are defined as follows: 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 Section 4 and 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 that 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] Annex G.1. 222 Use of the optional 0xFF trailer octet is discussed in [BACnet] 223 Clause 9. 225 1.4. Goals and Constraints 227 The main goals of this specification are to a) enable IPv6 directly 228 on wired end devices in building automation and control networks by 229 leveraging existing standards to the greatest extent possible, and b) 230 co-exist with legacy MS/TP implementations. Co-existence allows MS/ 231 TP networks to be incrementally upgraded to support IPv6. 233 In order to co-exist with legacy devices, no changes are permitted to 234 the MS/TP addressing modes, frame header format, control frames, or 235 Master Node state machine as specified in [BACnet] Clause 9. 237 2. Profile for IPv6 over MS/TP 239 ASHRAE has assigned an MS/TP Frame Type value of 34 to indicate IPv6 240 over MS/TP (LoBAC) Encapsulation. This falls within the range of 241 values that designate COBS-encoded data frames. 243 2.1. Mandatory Features 245 Nodes that support IPv6 over MS/TP must implement the Master Node 246 state machine as specified in [BACnet] Clause 9 and handle Token, 247 Poll For Master, and Reply to Poll For Master control frames. 248 Additionally, nodes must implement a Receive Frame state machine as 249 specified in [BACnet] Clause 9 that handles COBS-encoded frames. 251 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 specified in 253 [BACnet] Clause 9. 255 2.2. Configuration Constants 257 The following constants are used by the Receive Frame state machine. 259 Nmin_COBS_length The minimum valid length of any LoBAC encapsulated 260 frame: 5 262 Nmax_COBS_length The maximum valid length of any LoBAC encapsulated 263 frame: 1509 265 2.3. Configuration Parameters 267 The following parameters are used by the Master Node state machine. 269 Nmax_info_frames The default maximum number of information frames 270 the node may send before it must pass the token: 1 272 Nmax_master The default highest allowable address for master 273 nodes: 127 275 The mechanisms for setting parameters or monitoring MS/TP performance 276 are outside the scope of this specification. 278 3. Addressing Modes 280 MS/TP node (MAC) addresses are one octet in length and assigned 281 dynamically. The method of assigning MAC addresses is outside the 282 scope of this specification. However, each MS/TP node on the link 283 MUST have a unique address in order to ensure correct MAC operation. 285 [BACnet] Clause 9 specifies that addresses 0 through 127 are valid 286 for master nodes. The method specified in Section 6 for creating a 287 MAC-address-derived Interface Identifier (IID) ensures that an IID of 288 all zeros can never be generated. 290 A Destination Address of 255 (all nodes) indicates a MAC-layer 291 broadcast. MS/TP does not support multicast, therefore all IPv6 292 multicast packets MUST be broadcast at the MAC layer and filtered at 293 the IPv6 layer. A Source Address of 255 MUST NOT be used. 295 Hosts learn IPv6 prefixes via router advertisements according to 296 [RFC4861]. 298 4. Maximum Transmission Unit (MTU) 300 Upon transmission, the network layer MTU is formatted according to 301 Section 5 and becomes the MAC service data unit (MSDU). The MSDU is 302 then COBS encoded by MS/TP. Upon reception, the steps are reversed. 303 [BACnet] Clause 9 supports MSDUs up to 2032 octets in length. 305 IPv6 [RFC2460] requires that every link in the internet have an MTU 306 of 1280 octets or greater. Additionally, a node must be able to 307 accept a fragmented packet that, after reassembly, is as large as 308 1500 octets. This specification defines an MSDU length of at least 309 1280 octets and at most 1500 octets. Support for an MSDU length of 310 1500 octets is RECOMMENDED. 312 5. LoBAC Adaptation Layer 314 This section specifies an adaptation layer to support compressed IPv6 315 headers as specified in Section 10. IPv6 header compression MUST be 316 implemented on all nodes. Implementations MAY also support Generic 317 Header Compression [RFC7400] for transport layer headers. 319 The LoBAC encapsulation format defined in this section describes the 320 MSDU of an IPv6 over MS/TP frame. The LoBAC payload (i.e., an IPv6 321 packet) follows an encapsulation header stack. LoBAC is a subset of 322 the LoWPAN encapsulation defined in [RFC4944] as updated by 323 [RFC6282], therefore the use of "LOWPAN" in literals below is 324 intentional. The primary difference between LoWPAN and LoBAC is 325 omission of the Mesh, Broadcast, Fragmentation, and LOWPAN_HC1 326 headers. 328 All LoBAC encapsulated datagrams transmitted over MS/TP are prefixed 329 by an encapsulation header stack consisting of a Dispatch value 330 followed by zero or more header fields. The only sequence currently 331 defined for LoBAC is the LOWPAN_IPHC header followed by payload, as 332 shown below: 334 +---------------+---------------+------...-----+ 335 | IPHC Dispatch | IPHC Header | Payload | 336 +---------------+---------------+------...-----+ 338 Figure 2: A LoBAC Encapsulated LOWPAN_IPHC Compressed IPv6 Datagram 340 The Dispatch value is treated as an unstructured namespace. Only a 341 single pattern is used to represent current LoBAC functionality. 343 Pattern Header Type 344 +------------+-----------------------------------------------------+ 345 | 01 1xxxxx | LOWPAN_IPHC - LOWPAN_IPHC compressed IPv6 [RFC6282] | 346 +------------+-----------------------------------------------------+ 348 Figure 3: LoBAC Dispatch Value Bit Pattern 350 Other IANA-assigned 6LoWPAN Dispatch values do not apply to 6LoBAC 351 unless otherwise specified. 353 6. Stateless Address Autoconfiguration 355 This section defines how to obtain an IPv6 Interface Identifier. 356 This specification distinguishes between two types of IID, MAC- 357 address-derived and semantically opaque. 359 A MAC-address-derived IID is the RECOMMENDED type for use in forming 360 a link-local address, as it affords the most efficient header 361 compression provided by the LOWPAN_IPHC [RFC6282] format specified in 362 Section 10. The general procedure for creating a MAC-address-derived 363 IID is described in [RFC4291] Appendix A, "Creating Modified EUI-64 364 Format Interface Identifiers", as updated by [RFC7136]. 366 The Interface Identifier for link-local addresses SHOULD be formed by 367 concatenating the node's 8-bit MS/TP MAC address to the seven octets 368 0x00, 0x00, 0x00, 0xFF, 0xFE, 0x00, 0x00. For example, an MS/TP MAC 369 address of hexadecimal value 0x4F results in the following IID: 371 |0 1|1 3|3 4|4 6| 372 |0 5|6 1|2 7|8 3| 373 +----------------+----------------+----------------+----------------+ 374 |0000000000000000|0000000011111111|1111111000000000|0000000001001111| 375 +----------------+----------------+----------------+----------------+ 377 A semantically opaque IID having 64 bits of entropy is strongly 378 RECOMMENDED for each routable address and MAY be locally generated 379 according to one of the methods cited in Section 12. A node that 380 generates a 64-bit semantically opaque IID MUST register the IID with 381 its local router(s) by sending a Neighbor Solicitation (NS) message 382 with the Address Registration Option (ARO) and process Neighbor 383 Advertisements (NA) according to [RFC6775]. 385 An IPv6 address prefix used for stateless autoconfiguration [RFC4862] 386 of an MS/TP interface MUST have a length of 64 bits. 388 7. IPv6 Link Local Address 390 The IPv6 link-local address [RFC4291] for an MS/TP interface is 391 formed by appending the Interface Identifier, as defined above, to 392 the prefix FE80::/64. 394 10 bits 54 bits 64 bits 395 +----------+-----------------------+----------------------------+ 396 |1111111010| (zeros) | Interface Identifier | 397 +----------+-----------------------+----------------------------+ 399 8. Unicast Address Mapping 401 The address resolution procedure for mapping IPv6 non-multicast 402 addresses into MS/TP MAC-layer addresses follows the general 403 description in Section 7.2 of [RFC4861], unless otherwise specified. 405 The Source/Target Link-layer Address option has the following form 406 when the addresses are 8-bit MS/TP MAC-layer (node) addresses. 408 0 1 409 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 410 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 411 | Type | Length=1 | 412 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 413 | 0x00 | MS/TP Address | 414 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 415 | | 416 + Padding (all zeros) + 417 | | 418 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 420 Option fields: 422 Type: 424 1: for Source Link-layer address. 426 2: for Target Link-layer address. 428 Length: This is the length of this option (including the type and 429 length fields) in units of 8 octets. The value of this field is 1 430 for 8-bit MS/TP MAC addresses. 432 MS/TP Address: The 8-bit address in canonical bit order [RFC2469]. 433 This is the unicast address the interface currently responds to. 435 9. Multicast Address Mapping 437 All IPv6 multicast packets MUST be sent to MS/TP Destination Address 438 255 (broadcast) and filtered at the IPv6 layer. When represented as 439 a 16-bit address in a compressed header (see Section 10), it MUST be 440 formed by padding on the left with a zero octet: 442 0 1 443 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 444 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 445 | 0x00 | 0xFF | 446 +-+-+-+-+-+-+-+-+---------------+ 448 10. Header Compression 450 LoBAC uses LOWPAN_IPHC IPv6 compression, which is specified in 451 [RFC6282] and included herein by reference. This section will simply 452 identify substitutions that should be made when interpreting the text 453 of [RFC6282]. 455 In general the following substitutions should be made: 457 - Replace instances of "6LoWPAN" with "MS/TP network" 459 - Replace instances of "IEEE 802.15.4 address" with "MS/TP address" 461 When a 16-bit address is called for (i.e., an IEEE 802.15.4 "short 462 address") it MUST be formed by padding the MS/TP address to the left 463 with a zero octet: 465 0 1 466 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 467 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 468 | 0x00 | MS/TP address | 469 +-+-+-+-+-+-+-+-+---------------+ 471 If LOWPAN_IPHC compression [RFC6282] is used with context, the 472 router(s) directly attached to the MS/TP segment MUST disseminate the 473 6LoWPAN Context Option (6CO) according to [RFC6775], Section 7.2. 475 11. IANA Considerations 477 This document uses values previously reserved by [RFC4944] and 478 [RFC6282] and makes no further requests of IANA. 480 Note to RFC Editor: this section may be removed upon publication. 482 12. Security Considerations 484 See [I-D.ietf-6lo-privacy-considerations] for a general discussion of 485 privacy threats faced by constrained nodes. 487 [I-D.ietf-6lo-privacy-considerations] makes a distinction between 488 "stable" and "temporary" addresses. The former are long-lived and 489 typically advertised by servers. The latter are typically used by 490 clients and SHOULD be changed frequently to mitigate correlation of 491 activities over time. Nodes that engage in both activities SHOULD 492 support simultaneous use of multiple addresses per device. 494 Globally scoped addresses that contain MAC-address-derived IIDs may 495 expose a network to address scanning attacks. For this reason, it is 496 strongly RECOMMENDED that a 64-bit semantically opaque IID be 497 generated for each globally scoped address in use according to, for 498 example, [RFC3315], [RFC3972], [RFC4941], [RFC5535], or [RFC7217]. 500 13. Acknowledgments 502 We are grateful to the authors of [RFC4944] and members of the IETF 503 6LoWPAN working group; this document borrows liberally from their 504 work. Ralph Droms and Brian Haberman provided indispensable guidance 505 and support from the outset. Peter van der Stok, James Woodyatt, and 506 Carsten Bormann provided detailed reviews. Stuart Cheshire invented 507 the very clever COBS encoding. Michael Osborne made the critical 508 observation that encoding the data and CRC32K fields separately would 509 allow the CRC to be calculated on-the-fly. Alexandru Petrescu, Brian 510 Frank, Geoff Mulligan, and Don Sturek offered valuable comments. 512 14. References 514 14.1. Normative References 516 [Addendum_an] 517 ASHRAE, "ANSI/ASHRAE Addenda an, at, au, av, aw, ax, and 518 az to ANSI/ASHRAE Standard 135-2012, BACnet - A Data 519 Communication Protocol for Building Automation and Control 520 Networks", July 2014, 521 . 524 [BACnet] American Society of Heating, Refrigerating, and Air- 525 Conditioning Engineers, "BACnet - A Data Communication 526 Protocol for Building Automation and Control Networks", 527 ANSI/ASHRAE 135-2016 (Clause 9), January 2016, 528 . 531 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 532 Requirement Levels", BCP 14, RFC 2119, 533 DOI 10.17487/RFC2119, March 1997, 534 . 536 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 537 (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460, 538 December 1998, . 540 [RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins, 541 C., and M. Carney, "Dynamic Host Configuration Protocol 542 for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July 543 2003, . 545 [RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)", 546 RFC 3972, DOI 10.17487/RFC3972, March 2005, 547 . 549 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 550 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 551 2006, . 553 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 554 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 555 DOI 10.17487/RFC4861, September 2007, 556 . 558 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 559 Address Autoconfiguration", RFC 4862, 560 DOI 10.17487/RFC4862, September 2007, 561 . 563 [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy 564 Extensions for Stateless Address Autoconfiguration in 565 IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007, 566 . 568 [RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, 569 "Transmission of IPv6 Packets over IEEE 802.15.4 570 Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007, 571 . 573 [RFC5535] Bagnulo, M., "Hash-Based Addresses (HBA)", RFC 5535, 574 DOI 10.17487/RFC5535, June 2009, 575 . 577 [RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6 578 Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, 579 DOI 10.17487/RFC6282, September 2011, 580 . 582 [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. 583 Bormann, "Neighbor Discovery Optimization for IPv6 over 584 Low-Power Wireless Personal Area Networks (6LoWPANs)", 585 RFC 6775, DOI 10.17487/RFC6775, November 2012, 586 . 588 [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 589 Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136, 590 February 2014, . 592 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 593 Interface Identifiers with IPv6 Stateless Address 594 Autoconfiguration (SLAAC)", RFC 7217, 595 DOI 10.17487/RFC7217, April 2014, 596 . 598 [RFC7400] Bormann, C., "6LoWPAN-GHC: Generic Header Compression for 599 IPv6 over Low-Power Wireless Personal Area Networks 600 (6LoWPANs)", RFC 7400, DOI 10.17487/RFC7400, November 601 2014, . 603 14.2. Informative References 605 [COBS] Cheshire, S. and M. Baker, "Consistent Overhead Byte 606 Stuffing", IEEE/ACM TRANSACTIONS ON NETWORKING, VOL.7, 607 NO.2 , April 1999, 608 . 610 [CRC32K] Koopman, P., "32-Bit Cyclic Redundancy Codes for Internet 611 Applications", IEEE/IFIP International Conference on 612 Dependable Systems and Networks (DSN 2002) , June 2002, 613 . 616 [I-D.ietf-6lo-privacy-considerations] 617 Thaler, D., "Privacy Considerations for IPv6 Adaptation 618 Layer Mechanisms", draft-ietf-6lo-privacy- 619 considerations-04 (work in progress), October 2016. 621 [IEEE.802.3] 622 "Information technology - Telecommunications and 623 information exchange between systems - Local and 624 metropolitan area networks - Specific requirements - Part 625 3: Carrier Sense Multiple Access with Collision Detection 626 (CMSA/CD) Access Method and Physical Layer 627 Specifications", IEEE Std 802.3-2012, December 2012, 628 . 630 [RFC2469] Narten, T. and C. Burton, "A Caution On The Canonical 631 Ordering Of Link-Layer Addresses", RFC 2469, 632 DOI 10.17487/RFC2469, December 1998, 633 . 635 [TIA-485-A] 636 Telecommunications Industry Association, "TIA-485-A, 637 Electrical Characteristics of Generators and Receivers for 638 Use in Balanced Digital Multipoint Systems (ANSI/TIA/EIA- 639 485-A-98) (R2003)", March 2003. 641 Appendix A. Abstract MAC Interface 643 This Appendix is informative and not part of the standard. 645 [BACnet] Clause 9 provides support for MAC-layer clients through its 646 SendFrame and ReceivedDataNoReply procedures. However, it does not 647 define a network-protocol independent abstract interface for the MAC. 648 This is provided below as an aid to implementation. 650 A.1. MA-DATA.request 652 A.1.1. Function 654 This primitive defines the transfer of data from a MAC client entity 655 to a single peer entity or multiple peer entities in the case of a 656 broadcast address. 658 A.1.2. Semantics of the Service Primitive 660 The semantics of the primitive are as follows: 662 MA-DATA.request ( 663 destination_address, 664 source_address, 665 data, 666 type 667 ) 669 The 'destination_address' parameter may specify either an individual 670 or a broadcast MAC entity address. It must contain sufficient 671 information to create the Destination Address field (see Section 1.3) 672 that is prepended to the frame by the local MAC sublayer entity. The 673 'source_address' parameter, if present, must specify an individual 674 MAC address. If the source_address parameter is omitted, the local 675 MAC sublayer entity will insert a value associated with that entity. 677 The 'data' parameter specifies the MAC service data unit (MSDU) to be 678 transferred by the MAC sublayer entity. There is sufficient 679 information associated with the MSDU for the MAC sublayer entity to 680 determine the length of the data unit. 682 The 'type' parameter specifies the value of the MS/TP Frame Type 683 field that is prepended to the frame by the local MAC sublayer 684 entity. 686 A.1.3. When Generated 688 This primitive is generated by the MAC client entity whenever data 689 shall be transferred to a peer entity or entities. This can be in 690 response to a request from higher protocol layers or from data 691 generated internally to the MAC client, such as a Token frame. 693 A.1.4. Effect on Receipt 695 Receipt of this primitive will cause the MAC entity to insert all MAC 696 specific fields, including Destination Address, Source Address, Frame 697 Type, and any fields that are unique to the particular media access 698 method, and pass the properly formed frame to the lower protocol 699 layers for transfer to the peer MAC sublayer entity or entities. 701 A.2. MA-DATA.indication 703 A.2.1. Function 705 This primitive defines the transfer of data from the MAC sublayer 706 entity to the MAC client entity or entities in the case of a 707 broadcast address. 709 A.2.2. Semantics of the Service Primitive 710 The semantics of the primitive are as follows: 712 MA-DATA.indication ( 713 destination_address, 714 source_address, 715 data, 716 type 717 ) 719 The 'destination_address' parameter may be either an individual or a 720 broadcast address as specified by the Destination Address field of 721 the incoming frame. The 'source_address' parameter is an individual 722 address as specified by the Source Address field of the incoming 723 frame. 725 The 'data' parameter specifies the MAC service data unit (MSDU) as 726 received by the local MAC entity. There is sufficient information 727 associated with the MSDU for the MAC sublayer client to determine the 728 length of the data unit. 730 The 'type' parameter is the value of the MS/TP Frame Type field of 731 the incoming frame. 733 A.2.3. When Generated 735 The MA_DATA.indication is passed from the MAC sublayer entity to the 736 MAC client entity or entities to indicate the arrival of a frame to 737 the local MAC sublayer entity that is destined for the MAC client. 738 Such frames are reported only if they are validly formed, received 739 without error, and their destination address designates the local MAC 740 entity. Frames destined for the MAC Control sublayer are not passed 741 to the MAC client. 743 A.2.4. Effect on Receipt 745 The effect of receipt of this primitive by the MAC client is 746 unspecified. 748 Appendix B. Consistent Overhead Byte Stuffing [COBS] 750 This Appendix is informative and not part of the standard. 752 [BACnet] Clause 9 corrects a long-standing issue with the MS/TP 753 specification; namely that preamble sequences were not escaped 754 whenever they appeared in the Data or Data CRC fields. In rare 755 cases, this resulted in dropped frames due to loss of frame 756 synchronization. The solution is to encode the Data and 32-bit Data 757 CRC fields before transmission using Consistent Overhead Byte 758 Stuffing [COBS] and decode these fields upon reception. 760 COBS is a run-length encoding method that nominally removes '0x00' 761 octets from its input. Any selected octet value may be removed by 762 XOR'ing that value with each octet of the COBS output. [BACnet] 763 Clause 9 specifies the preamble octet '0x55' for removal. 765 The minimum overhead of COBS is one octet per encoded field. The 766 worst-case overhead in long fields is bounded to one octet per 254 as 767 described in [COBS]. 769 Frame encoding proceeds logically in two passes. The Encoded Data 770 field is prepared by passing the MSDU through the COBS encoder and 771 XOR'ing the preamble octet '0x55' with each octet of the output. The 772 Encoded CRC-32K field is then prepared by calculating a CRC-32K over 773 the Encoded Data field and formatting it for transmission as 774 described in Appendix C. The combined length of these fields, minus 775 two octets for compatibility with existing MS/TP devices, is placed 776 in the MS/TP header Length field before transmission. 778 Example COBS encoder and decoder functions are shown below for 779 illustration. Complete examples of use and test vectors are provided 780 in [BACnet] Clause 9. 782 784 #include 785 #include 787 /* 788 * Encodes 'length' octets of data located at 'from' and 789 * writes one or more COBS code blocks at 'to', removing any 790 * 'mask' octets that may present be in the encoded data. 791 * Returns the length of the encoded data. 792 */ 794 size_t 795 cobs_encode (uint8_t *to, const uint8_t *from, size_t length, 796 uint8_t mask) 797 { 798 size_t code_index = 0; 799 size_t read_index = 0; 800 size_t write_index = 1; 801 uint8_t code = 1; 802 uint8_t data, last_code; 804 while (read_index < length) { 805 data = from[read_index++]; 806 /* 807 * In the case of encountering a non-zero octet in the data, 808 * simply copy input to output and increment the code octet. 809 */ 810 if (data != 0) { 811 to[write_index++] = data ^ mask; 812 code++; 813 if (code != 255) 814 continue; 815 } 816 /* 817 * In the case of encountering a zero in the data or having 818 * copied the maximum number (254) of non-zero octets, store 819 * the code octet and reset the encoder state variables. 820 */ 821 last_code = code; 822 to[code_index] = code ^ mask; 823 code_index = write_index++; 824 code = 1; 825 } 826 /* 827 * If the last chunk contains exactly 254 non-zero octets, then 828 * this exception is handled above (and returned length must be 829 * adjusted). Otherwise, encode the last chunk normally, as if 830 * a "phantom zero" is appended to the data. 831 */ 832 if ((last_code == 255) && (code == 1)) 833 write_index--; 834 else 835 to[code_index] = code ^ mask; 837 return write_index; 838 } 839 #include 840 #include 842 /* 843 * Decodes 'length' octets of data located at 'from' and 844 * writes the original client data at 'to', restoring any 845 * 'mask' octets that may present in the encoded data. 846 * Returns the length of the encoded data or zero if error. 847 */ 848 size_t 849 cobs_decode (uint8_t *to, const uint8_t *from, size_t length, 850 uint8_t mask) 851 { 852 size_t read_index = 0; 853 size_t write_index = 0; 854 uint8_t code, last_code; 856 while (read_index < length) { 857 code = from[read_index] ^ mask; 858 last_code = code; 859 /* 860 * Sanity check the encoding to prevent the while() loop below 861 * from overrunning the output buffer. 862 */ 863 if (read_index + code > length) 864 return 0; 866 read_index++; 867 while (--code > 0) 868 to[write_index++] = from[read_index++] ^ mask; 869 /* 870 * Restore the implicit zero at the end of each decoded block 871 * except when it contains exactly 254 non-zero octets or the 872 * end of data has been reached. 873 */ 874 if ((last_code != 255) && (read_index < length)) 875 to[write_index++] = 0; 876 } 877 return write_index; 878 } 880 882 Appendix C. Encoded CRC-32K [CRC32K] 884 This Appendix is informative and not part of the standard. 886 Extending the payload of MS/TP to 1500 octets required upgrading the 887 Data CRC from 16 bits to 32 bits. P.Koopman has authored several 888 papers on evaluating CRC polynomials for network applications. In 889 [CRC32K], he surveyed the entire 32-bit polynomial space and noted 890 some that exceed the [IEEE.802.3] polynomial in performance. 891 [BACnet] Clause 9 specifies one of these, the CRC-32K (Koopman) 892 polynomial. 894 The specified use of the calc_crc32K() function is as follows. 895 Before a frame is transmitted, 'crc_value' is initialized to all 896 ones. After passing each octet of the [COBS] Encoded Data through 897 the function, the ones complement of the resulting 'crc_value' is 898 arranged in LSB-first order and is itself [COBS] encoded. The length 899 of the resulting Encoded CRC-32K field is always five octets. 901 Upon reception of a frame, 'crc_value' is initialized to all ones. 902 The octets of the Encoded Data field are accumulated by the 903 calc_crc32K() function before decoding. The Encoded CRC-32K field is 904 then decoded and the resulting four octets are accumulated by the 905 calc_crc32K() function. If the result is the expected residue value 906 'CRC32K_RESIDUE', then the frame was received correctly. 908 An example CRC-32K function in shown below for illustration. 909 Complete examples of use and test vectors are provided in [BACnet] 910 Clause 9. 912 914 #include 916 /* See BACnet Addendum 135-2012an, section G.3.2 */ 917 #define CRC32K_INITIAL_VALUE (0xFFFFFFFF) 918 #define CRC32K_RESIDUE (0x0843323B) 920 /* CRC-32K polynomial, 1 + x**1 + ... + x**30 (+ x**32) */ 921 #define CRC32K_POLY (0xEB31D82E) 923 /* 924 * Accumulate 'data_value' into the CRC in 'crc_value'. 925 * Return updated CRC. 926 * 927 * Note: crc_value must be set to CRC32K_INITIAL_VALUE 928 * before initial call. 929 */ 930 uint32_t 931 calc_crc32K (uint8_t data_value, uint32_t crc_value) 932 { 933 int b; 935 for (b = 0; b < 8; b++) { 936 if ((data_value & 1) ^ (crc_value & 1)) { 937 crc_value >>= 1; 938 crc_value ^= CRC32K_POLY; 939 } else { 940 crc_value >>= 1; 941 } 942 data_value >>= 1; 943 } 944 return crc_value; 945 } 947 949 Appendix D. Example 6LoBAC Packet Decode 951 This Appendix is informative and not part of the standard. 953 BACnet MS/TP, Src (2), Dst (1), IPv6 Encapsulation 954 Preamble 55: 0x55 955 Preamble FF: 0xff 956 Frame Type: IPv6 Encapsulation (34) 957 Destination Address: 1 958 Source Address: 2 959 Length: 537 960 Header CRC: 0x1c [correct] 961 Extended Data CRC: 0x9e7259e2 [correct] 962 6LoWPAN 963 IPHC Header 964 011. .... = Pattern: IP header compression (0x03) 965 ...1 1... .... .... = Traffic class and flow label: 966 Version, traffic class, and flow label 967 compressed (0x0003) 968 .... .0.. .... .... = Next header: Inline 969 .... ..00 .... .... = Hop limit: Inline (0x0000) 970 .... .... 1... .... = Context identifier extension: True 971 .... .... .1.. .... = Source address compression: Stateful 972 .... .... ..01 .... = Source address mode: 973 64-bits inline (0x0001) 974 .... .... .... 0... = Multicast address compression: False 975 .... .... .... .1.. = Destination address compression: 976 Stateful 977 .... .... .... ..10 = Destination address mode: 978 16-bits inline (0x0002) 979 0000 .... = Source context identifier: 0x00 980 .... 0000 = Destination context identifier: 0x00 981 [Source context: aaaa:: (aaaa::)] 982 [Destination context: aaaa:: (aaaa::)] 983 Next header: ICMPv6 (0x3a) 984 Hop limit: 63 985 Source: aaaa::1 (aaaa::1) 986 Destination: aaaa::ff:fe00:1 (aaaa::ff:fe00:1) 987 Internet Protocol Version 6, Src: aaaa::1 (aaaa::1), 988 Dst: aaaa::ff:fe00:1 (aaaa::ff:fe00:1) 989 0110 .... .... .... .... .... .... .... = Version: 6 990 .... 0000 0000 .... .... .... .... .... = Traffic class: 991 0x00000000 992 .... 0000 00.. .... .... .... .... .... = Differentiated 993 Services Field: 994 Default (0x00000000) 995 .... .... ..0. .... .... .... .... .... = ECN-Capable Transport 996 (ECT): Not set 997 .... .... ...0 .... .... .... .... .... = ECN-CE: Not set 998 .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000 999 Payload length: 518 1000 Next header: ICMPv6 (58) 1001 Hop limit: 63 1002 Source: aaaa::1 (aaaa::1) 1003 Destination: aaaa::ff:fe00:1 (aaaa::ff:fe00:1) 1004 Internet Control Message Protocol v6 1005 Type: Echo (ping) request (128) 1006 Code: 0 1007 Checksum: 0x783f [correct] 1008 Identifier: 0x2ee5 1009 Sequence: 2 1010 [Response In: 5165] 1011 Data (510 bytes) 1012 Data: e4dbe8553ba0040008090a0b0c0d0e0f1011121314151617... 1013 [Length: 510] 1015 Frame (547 bytes): 1016 55 ff 22 01 02 02 19 1c 56 2d 83 56 6f 6a 54 54 U.".....V-.VojTT 1017 54 54 54 54 57 54 56 54 d5 50 2d 6a 7b b0 5c 57 TTTTWTVT.P-j{.\W 1018 b1 8e bd 00 6e f5 51 ac 5d 5c 5f 5e 59 58 5b 5a ....n.Q.]\_^YX[Z 1019 45 44 47 46 41 40 43 42 4d 4c 4f 4e 49 48 4b 4a EDGFA@CBMLONIHKJ 1020 75 74 77 76 71 70 73 72 7d 7c 7f 7e 79 78 7b 7a utwvqpsr}|.~yx{z 1021 65 64 67 66 61 60 63 62 6d 6c 6f 6e 69 68 6b 6a edgfa`cbmlonihkj 1022 15 14 17 16 11 10 13 12 1d 1c 1f 1e 19 18 1b 1a ................ 1023 05 04 07 06 01 00 03 02 0d 0c 0f 0e 09 08 0b 0a ................ 1024 35 34 37 36 31 30 33 32 3d 3c 3f 3e 39 38 3b 3a 54761032=98;: 1025 25 24 27 26 21 20 23 22 2d 2c 2f 2e 29 28 2b 2a %$'&! #"-,/.)(+* 1026 d5 d4 d7 d6 d1 d0 d3 d2 dd dc df de d9 d8 db da ................ 1027 c5 c4 c7 c6 c1 c0 c3 c2 cd cc cf ce c9 c8 cb ca ................ 1028 f5 f4 f7 f6 f1 f0 f3 f2 fd fc ff fe f9 f8 fb fa ................ 1029 e5 e4 e7 e6 e1 e0 e3 e2 ed ec ef ee e9 e8 eb ea ................ 1030 95 94 97 96 91 90 93 92 9d 9c 9f 9e 99 98 9b 9a ................ 1031 85 84 87 86 81 80 83 82 8d 8c 8f 8e 89 88 8b 8a ................ 1032 b5 b4 b7 b6 b1 b0 b3 b2 bd bc bf be b9 b8 bb ba ................ 1033 a5 a4 a7 a6 a1 a0 a3 a2 ad ac af ae a9 a8 ab aa ................ 1034 ab 54 57 56 51 50 53 52 5d 5c 5f 5e 59 58 5b 5a .TWVQPSR]\_^YX[Z 1035 45 44 47 46 41 40 43 42 4d 4c 4f 4e 49 48 4b 4a EDGFA@CBMLONIHKJ 1036 75 74 77 76 71 70 73 72 7d 7c 7f 7e 79 78 7b 7a utwvqpsr}|.~yx{z 1037 65 64 67 66 61 60 63 62 6d 6c 6f 6e 69 68 6b 6a edgfa`cbmlonihkj 1038 15 14 17 16 11 10 13 12 1d 1c 1f 1e 19 18 1b 1a ................ 1039 05 04 07 06 01 00 03 02 0d 0c 0f 0e 09 08 0b 0a ................ 1040 35 34 37 36 31 30 33 32 3d 3c 3f 3e 39 38 3b 3a 54761032=98;: 1041 25 24 27 26 21 20 23 22 2d 2c 2f 2e 29 28 2b 2a %$'&! #"-,/.)(+* 1042 d5 d4 d7 d6 d1 d0 d3 d2 dd dc df de d9 d8 db da ................ 1043 c5 c4 c7 c6 c1 c0 c3 c2 cd cc cf ce c9 c8 cb ca ................ 1044 f5 f4 f7 f6 f1 f0 f3 f2 fd fc ff fe f9 f8 fb fa ................ 1045 e5 e4 e7 e6 e1 e0 e3 e2 ed ec ef ee e9 e8 eb ea ................ 1046 95 94 97 96 91 90 93 92 9d 9c 9f 9e 99 98 9b 9a ................ 1047 85 84 87 86 81 80 83 82 8d 8c 8f 8e 89 88 8b 8a ................ 1048 b5 b4 b7 b6 b1 b0 b3 b2 bd bc bf be b9 b8 bb ba ................ 1049 a5 a4 a7 a6 a1 a0 a3 a2 ad ac af ae a9 a8 50 cb ..............P. 1050 27 0c b7 '.. 1052 Decoded Data and CRC32K (537 bytes): 1053 78 d6 00 3a 3f 00 00 00 00 00 00 00 01 00 01 80 x..:?........... 1054 00 78 3f 2e e5 00 02 e4 db e8 55 3b a0 04 00 08 .x?.......U;.... 1055 09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 18 ................ 1056 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 ....... !"#$%&'( 1057 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 )*+,-./012345678 1058 39 3a 3b 3c 3d 3e 3f 40 41 42 43 44 45 46 47 48 9:;<=>?@ABCDEFGH 1059 49 4a 4b 4c 4d 4e 4f 50 51 52 53 54 55 56 57 58 IJKLMNOPQRSTUVWX 1060 59 5a 5b 5c 5d 5e 5f 60 61 62 63 64 65 66 67 68 YZ[\]^_`abcdefgh 1061 69 6a 6b 6c 6d 6e 6f 70 71 72 73 74 75 76 77 78 ijklmnopqrstuvwx 1062 79 7a 7b 7c 7d 7e 7f 80 81 82 83 84 85 86 87 88 yz{|}~.......... 1063 89 8a 8b 8c 8d 8e 8f 90 91 92 93 94 95 96 97 98 ................ 1064 99 9a 9b 9c 9d 9e 9f a0 a1 a2 a3 a4 a5 a6 a7 a8 ................ 1065 a9 aa ab ac ad ae af b0 b1 b2 b3 b4 b5 b6 b7 b8 ................ 1066 b9 ba bb bc bd be bf c0 c1 c2 c3 c4 c5 c6 c7 c8 ................ 1067 c9 ca cb cc cd ce cf d0 d1 d2 d3 d4 d5 d6 d7 d8 ................ 1068 d9 da db dc dd de df e0 e1 e2 e3 e4 e5 e6 e7 e8 ................ 1069 e9 ea eb ec ed ee ef f0 f1 f2 f3 f4 f5 f6 f7 f8 ................ 1070 f9 fa fb fc fd fe ff 00 01 02 03 04 05 06 07 08 ................ 1071 09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 18 ................ 1072 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 ....... !"#$%&'( 1073 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 )*+,-./012345678 1074 39 3a 3b 3c 3d 3e 3f 40 41 42 43 44 45 46 47 48 9:;<=>?@ABCDEFGH 1075 49 4a 4b 4c 4d 4e 4f 50 51 52 53 54 55 56 57 58 IJKLMNOPQRSTUVWX 1076 59 5a 5b 5c 5d 5e 5f 60 61 62 63 64 65 66 67 68 YZ[\]^_`abcdefgh 1077 69 6a 6b 6c 6d 6e 6f 70 71 72 73 74 75 76 77 78 ijklmnopqrstuvwx 1078 79 7a 7b 7c 7d 7e 7f 80 81 82 83 84 85 86 87 88 yz{|}~.......... 1079 89 8a 8b 8c 8d 8e 8f 90 91 92 93 94 95 96 97 98 ................ 1080 99 9a 9b 9c 9d 9e 9f a0 a1 a2 a3 a4 a5 a6 a7 a8 ................ 1081 a9 aa ab ac ad ae af b0 b1 b2 b3 b4 b5 b6 b7 b8 ................ 1082 b9 ba bb bc bd be bf c0 c1 c2 c3 c4 c5 c6 c7 c8 ................ 1083 c9 ca cb cc cd ce cf d0 d1 d2 d3 d4 d5 d6 d7 d8 ................ 1084 d9 da db dc dd de df e0 e1 e2 e3 e4 e5 e6 e7 e8 ................ 1085 e9 ea eb ec ed ee ef f0 f1 f2 f3 f4 f5 f6 f7 f8 ................ 1086 f9 fa fb fc fd 9e 72 59 e2 ......rY. 1088 Decompressed 6LoWPAN IPHC (558 bytes): 1089 60 00 00 00 02 06 3a 3f aa aa 00 00 00 00 00 00 `.....:?........ 1090 00 00 00 00 00 00 00 01 aa aa 00 00 00 00 00 00 ................ 1091 00 00 00 ff fe 00 00 01 80 00 78 3f 2e e5 00 02 ..........x?.... 1092 e4 db e8 55 3b a0 04 00 08 09 0a 0b 0c 0d 0e 0f ...U;........... 1093 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f ................ 1094 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f !"#$%&'()*+,-./ 1095 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 0123456789:;<=>? 1096 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO 1097 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f PQRSTUVWXYZ[\]^_ 1098 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f `abcdefghijklmno 1099 70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f pqrstuvwxyz{|}~. 1100 80 81 82 83 84 85 86 87 88 89 8a 8b 8c 8d 8e 8f ................ 1101 90 91 92 93 94 95 96 97 98 99 9a 9b 9c 9d 9e 9f ................ 1102 a0 a1 a2 a3 a4 a5 a6 a7 a8 a9 aa ab ac ad ae af ................ 1103 b0 b1 b2 b3 b4 b5 b6 b7 b8 b9 ba bb bc bd be bf ................ 1104 c0 c1 c2 c3 c4 c5 c6 c7 c8 c9 ca cb cc cd ce cf ................ 1105 d0 d1 d2 d3 d4 d5 d6 d7 d8 d9 da db dc dd de df ................ 1106 e0 e1 e2 e3 e4 e5 e6 e7 e8 e9 ea eb ec ed ee ef ................ 1107 f0 f1 f2 f3 f4 f5 f6 f7 f8 f9 fa fb fc fd fe ff ................ 1108 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f ................ 1109 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f ................ 1110 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f !"#$%&'()*+,-./ 1111 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 0123456789:;<=>? 1112 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO 1113 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f PQRSTUVWXYZ[\]^_ 1114 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f `abcdefghijklmno 1115 70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f pqrstuvwxyz{|}~. 1116 80 81 82 83 84 85 86 87 88 89 8a 8b 8c 8d 8e 8f ................ 1117 90 91 92 93 94 95 96 97 98 99 9a 9b 9c 9d 9e 9f ................ 1118 a0 a1 a2 a3 a4 a5 a6 a7 a8 a9 aa ab ac ad ae af ................ 1119 b0 b1 b2 b3 b4 b5 b6 b7 b8 b9 ba bb bc bd be bf ................ 1120 c0 c1 c2 c3 c4 c5 c6 c7 c8 c9 ca cb cc cd ce cf ................ 1121 d0 d1 d2 d3 d4 d5 d6 d7 d8 d9 da db dc dd de df ................ 1122 e0 e1 e2 e3 e4 e5 e6 e7 e8 e9 ea eb ec ed ee ef ................ 1123 f0 f1 f2 f3 f4 f5 f6 f7 f8 f9 fa fb fc fd .............. 1125 Authors' Addresses 1127 Kerry Lynn (editor) 1128 Verizon Labs 1129 50 Sylvan Rd 1130 Waltham , MA 02451 1131 USA 1133 Phone: +1 781 296 9722 1134 Email: kerlyn@ieee.org 1136 Jerry Martocci 1137 Johnson Controls, Inc. 1138 507 E. Michigan St 1139 Milwaukee , WI 53202 1140 USA 1142 Email: jpmartocci@sbcglobal.net 1144 Carl Neilson 1145 Delta Controls, Inc. 1146 17850 56th Ave 1147 Surrey , BC V3S 1C7 1148 Canada 1150 Phone: +1 604 575 5913 1151 Email: cneilson@deltacontrols.com 1153 Stuart Donaldson 1154 Honeywell Automation & Control Solutions 1155 6670 185th Ave NE 1156 Redmond , WA 98052 1157 USA 1159 Email: stuart.donaldson@honeywell.com