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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 6TiSCH Q. Wang, Ed. 3 Internet-Draft Univ. of Sci. and Tech. Beijing 4 Intended status: Standards Track X. Vilajosana 5 Expires: December 24, 2017 Universitat Oberta de Catalunya 6 T. Watteyne 7 Analog Devices 8 June 22, 2017 10 6top Protocol (6P) 11 draft-ietf-6tisch-6top-protocol-06 13 Abstract 15 This document defines the 6top Protocol (6P), which enables 16 distributed scheduling in 6TiSCH networks. 6P allows neighbor nodes 17 to add/delete TSCH cells to one another. 6P is part of the 6TiSCH 18 Operation Sublayer (6top), the next higher layer to the IEEE Std 19 802.15.4 TSCH medium access control layer. The 6top Scheduling 20 Function (SF) decides when to add/delete cells, and triggers 6P 21 Transactions. Several SFs can be defined, each identified by a 22 different 6top Scheduling Function Identifier (SFID). This document 23 lists the requirements for an SF, but leaves the definition of the SF 24 out of scope. SFs are expected to be defined in future companion 25 specifications. 27 Requirements Language 29 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 30 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 31 "OPTIONAL" in this document are to be interpreted as described in RFC 32 2119 [RFC2119]. 34 Status of This Memo 36 This Internet-Draft is submitted in full conformance with the 37 provisions of BCP 78 and BCP 79. 39 Internet-Drafts are working documents of the Internet Engineering 40 Task Force (IETF). Note that other groups may also distribute 41 working documents as Internet-Drafts. The list of current Internet- 42 Drafts is at http://datatracker.ietf.org/drafts/current/. 44 Internet-Drafts are draft documents valid for a maximum of six months 45 and may be updated, replaced, or obsoleted by other documents at any 46 time. It is inappropriate to use Internet-Drafts as reference 47 material or to cite them other than as "work in progress." 48 This Internet-Draft will expire on December 24, 2017. 50 Copyright Notice 52 Copyright (c) 2017 IETF Trust and the persons identified as the 53 document authors. All rights reserved. 55 This document is subject to BCP 78 and the IETF Trust's Legal 56 Provisions Relating to IETF Documents 57 (http://trustee.ietf.org/license-info) in effect on the date of 58 publication of this document. Please review these documents 59 carefully, as they describe your rights and restrictions with respect 60 to this document. Code Components extracted from this document must 61 include Simplified BSD License text as described in Section 4.e of 62 the Trust Legal Provisions and are provided without warranty as 63 described in the Simplified BSD License. 65 Table of Contents 67 1. TEMPORARY EDITORIAL NOTES . . . . . . . . . . . . . . . . . . 3 68 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 69 3. 6TiSCH Operation Sublayer (6top) . . . . . . . . . . . . . . 5 70 3.1. Hard/Soft Cells . . . . . . . . . . . . . . . . . . . . . 5 71 3.2. Using 6P with the Minimal 6TiSCH Configuration . . . . . 6 72 4. 6top Protocol (6P) . . . . . . . . . . . . . . . . . . . . . 6 73 4.1. 6P Transactions . . . . . . . . . . . . . . . . . . . . . 7 74 4.1.1. 2-step 6P Transaction . . . . . . . . . . . . . . . . 7 75 4.1.2. 3-step 6P Transaction . . . . . . . . . . . . . . . . 8 76 4.2. Message Format . . . . . . . . . . . . . . . . . . . . . 10 77 4.2.1. 6top Information Element (IE) . . . . . . . . . . . . 10 78 4.2.2. Generic 6P Message Format . . . . . . . . . . . . . . 10 79 4.2.3. 6P CellOptions . . . . . . . . . . . . . . . . . . . 11 80 4.2.4. 6P CellList . . . . . . . . . . . . . . . . . . . . . 12 81 4.3. 6P Commands and Operations . . . . . . . . . . . . . . . 13 82 4.3.1. Adding Cells . . . . . . . . . . . . . . . . . . . . 13 83 4.3.2. Deleting Cells . . . . . . . . . . . . . . . . . . . 14 84 4.3.3. Relocating Cells . . . . . . . . . . . . . . . . . . 16 85 4.3.4. Counting Cells . . . . . . . . . . . . . . . . . . . 18 86 4.3.5. Listing Cells . . . . . . . . . . . . . . . . . . . . 19 87 4.3.6. Clearing the Schedule . . . . . . . . . . . . . . . . 20 88 4.4. Protocol Functional Details . . . . . . . . . . . . . . . 21 89 4.4.1. Version Checking . . . . . . . . . . . . . . . . . . 21 90 4.4.2. SFID Checking . . . . . . . . . . . . . . . . . . . . 22 91 4.4.3. Concurrent 6P Transactions . . . . . . . . . . . . . 22 92 4.4.4. Timeout . . . . . . . . . . . . . . . . . . . . . . . 22 93 4.4.5. SeqNum Mismatch . . . . . . . . . . . . . . . . . . . 23 94 4.4.6. Aborting a 6P Transaction . . . . . . . . . . . . . . 23 95 4.4.7. Generation Management . . . . . . . . . . . . . . . . 23 96 4.4.8. Handling Error Responses . . . . . . . . . . . . . . 24 97 4.5. Security . . . . . . . . . . . . . . . . . . . . . . . . 25 98 5. Guidelines for 6top Scheduling Functions (SF) . . . . . . . . 25 99 5.1. SF Identifier (SFID) . . . . . . . . . . . . . . . . . . 25 100 5.2. Requirements for an SF . . . . . . . . . . . . . . . . . 25 101 5.3. Recommended Structure of an SF Specification . . . . . . 26 102 6. Implementation Status . . . . . . . . . . . . . . . . . . . . 26 103 7. Security Considerations . . . . . . . . . . . . . . . . . . . 27 104 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27 105 8.1. IETF IE Subtype '6P' . . . . . . . . . . . . . . . . . . 27 106 8.2. 6TiSCH parameters sub-registries . . . . . . . . . . . . 28 107 8.2.1. 6P Version Numbers . . . . . . . . . . . . . . . . . 28 108 8.2.2. 6P Message Types . . . . . . . . . . . . . . . . . . 28 109 8.2.3. 6P Command Identifiers . . . . . . . . . . . . . . . 29 110 8.2.4. 6P Return Codes . . . . . . . . . . . . . . . . . . . 30 111 8.2.5. 6P Scheduling Function Identifiers . . . . . . . . . 31 112 8.2.6. 6P CellOptions bitmap . . . . . . . . . . . . . . . . 32 113 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 32 114 9.1. Normative References . . . . . . . . . . . . . . . . . . 33 115 9.2. Informative References . . . . . . . . . . . . . . . . . 33 116 Appendix A. [TEMPORARY] Changelog . . . . . . . . . . . . . . . 34 117 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36 119 1. TEMPORARY EDITORIAL NOTES 121 This document is an Internet Draft, so work-in-progress by nature. 122 It contains the following work-in-progress elements: 124 o "TODO" statements are elements which have not yet been written by 125 the authors for some reason (lack of time, ongoing discussions 126 with no clear consensus, etc). The statement does indicate that 127 the text will be written at some point in time. 128 o "TEMPORARY" appendices are there to capture current ongoing 129 discussions, or the changelog of the document. These appendices 130 will be removed in the final text. 131 o "IANA_*" identifiers are placeholders for numbers assigned by 132 IANA. These placeholders are to be replaced by the actual values 133 they represent after their assignment by IANA. 134 o "RFCXXXX" refers to the RFC number of this specification, once 135 published. 136 o The string "REMARK" is put before a remark (questions, suggestion, 137 etc) from an author, editor or contributor. These are on-going 138 discussions at the time of writing, NOT part of the final text. 139 o This section will be removed in the final text. 141 2. Introduction 143 All communication in a 6TiSCH network is orchestrated by a schedule 144 [RFC7554]. This specification defines the 6top Protocol (6P), part 145 of the 6TiSCH Operation sublayer (6top). 6P allows a node to 146 communicate with a neighbor to add/delete TSCH cells to one another. 147 This results in distributed schedule management in a 6TiSCH network. 149 (R) 150 / \ 151 / \ 152 (B)-----(C) 153 | | 154 | | 155 (A) (D) 157 Figure 1: A simple 6TiSCH network. 159 The example network depicted in Figure 1 is used to describe the 160 interaction between nodes. We consider the canonical case where node 161 "A" issues 6P requests to node "B". We keep this example throughout 162 this document. Throughout the document, node A will always represent 163 the node that issues a 6P request; node B the node that receives this 164 request. 166 We consider that node A monitors the communication cells it has in 167 its schedule to node B: 169 o If node A determines that the number of link-layer frames it is 170 sending to B per unit of time is larger than the capacity offered 171 by the TSCH cells it has scheduled to B, it triggers a 6P 172 Transaction with node B to add one or more cells to the TSCH 173 schedule of both nodes. 174 o If the traffic is lower than the capacity, node A triggers a 6P 175 Transaction with node B to delete one or more cells in the TSCH 176 schedule of both nodes. 177 o Node A MAY also monitor statistics to determine whether collisions 178 are happening on a particular cell to node B. If this feature is 179 enabled, node A communicates with node B to add a new cell and 180 delete the cell which suffered from collisions. This results in 181 "relocating" the cell which suffered from collisions to a 182 different [slotOffset,channelOffset] location in the TSCH 183 schedule. The mechanism to handle cell relocation is out of the 184 scope of this document and might be handled by the scheduling 185 function (see below). 187 This results in distributed schedule management in a 6TiSCH network. 189 The 6top Scheduling Function (SF) defines when to add/delete a cell 190 to a neighbor. Different applications require different SFs, so the 191 SF is left out of scope of this document. Different SFs are expected 192 to be defined in future companion specifications. A node MAY 193 implement multiple SFs and run them at the same time. At least one 194 SF MUST be running. The SFID field contained in all 6P messages 195 allows a node to invoke the appropriate SF on a per-transaction 196 basis. 198 Section 3 describes the 6TiSCH Operation Sublayer (6top). Section 4 199 defines the 6top Protocol (6P). Section 5 provides guidelines on how 200 to design an SF. 202 3. 6TiSCH Operation Sublayer (6top) 204 As depicted in Figure 2, the 6TiSCH Operation Sublayer (6top) is the 205 next higher layer to the IEEE Std 802.15.4 TSCH medium access control 206 (MAC) layer [IEEE802154-2015]. We use "802.15.4" as a short version 207 of "IEEE Std 802.15.4" in this document. 209 . 210 | . | 211 | higher layers | 212 +------------------------------------------+ 213 | 6top | 214 +------------------------------------------+ 215 | IEEE Std 802.15.4 TSCH | 216 | . | 217 . 219 Figure 2: The 6top sublayer in the protocol stack. 221 The roles of the 6top sublayer are to: 223 o Implement and terminate the 6top Protocol (6P), which allows 224 neighbor nodes to communicate to add/delete cells to one another. 225 o Run one or more 6top Scheduling Functions (SF), which define the 226 rules that decide when to add/delete cells. 228 3.1. Hard/Soft Cells 230 Each cell in the schedule is either "hard" or "soft": 232 o a soft cell can be read, added, deleted or updated by 6top. 233 o a hard cell is read-only for 6top. 235 In the context of this specification, all the cells used by 6top are 236 soft cells. Hard cells can be used for example when "hard-coding" a 237 schedule [I-D.ietf-6tisch-minimal]. 239 3.2. Using 6P with the Minimal 6TiSCH Configuration 241 6P MAY be used alongside the Minimal 6TiSCH Configuration 242 [I-D.ietf-6tisch-minimal]. In this case, it is RECOMMENDED to use 2 243 slotframes, as depicted in Figure 3: 245 o Slotframe 0 is used for traffic defined in the Minimal 6TiSCH 246 Configuration. In Figure 3, this slotframe is 5 slots long, but 247 the length can be shorter or longer. 248 o 6P allocates cells from Slotframe 1. In Figure 3, Slotframe 1 is 249 10 slots long, but the length can be shorter or longer. 251 | 0 1 2 3 4 | 0 1 2 3 4 | 252 +------------------------+------------------------+ 253 Slotframe 0 | | | | | | | | | | | 254 5 slots long | EB | | | | | EB | | | | | 255 | | | | | | | | | | | 256 +-------------------------------------------------+ 258 | 0 1 2 3 4 5 6 7 8 9 | 259 +-------------------------------------------------+ 260 Slotframe 1 | | | | | | | | | | | 261 10 slots long | |A->B| | | | | | |B->A| | 262 | | | | | | | | | | | 263 +-------------------------------------------------+ 265 Figure 3: 2-slotframe structure when using 6P alongside the Minimal 266 6TiSCH Configuration. 268 The Minimal 6TiSCH Configuration cell SHOULD be allocated from a 269 slotframe of higher priority than the slotframe used by 6P for 270 dynamic cell allocation. In this way, dynamically allocated cells 271 cannot "mask" the cells used by the Minimal 6TiSCH Configuration. 272 6top MAY support additional slotframes; how to use additional 273 slotframes is out of the scope for this document. 275 4. 6top Protocol (6P) 277 The 6top Protocol (6P) enables two neighbor nodes to add/delete/ 278 relocate cells to their TSCH schedule. Conceptually, two neighbor 279 nodes "negotiate" the location of the cells to add, delete, or 280 relocate. 282 4.1. 6P Transactions 284 We call "6P Transaction" a complete negotiation between two neighbor 285 nodes. A 6P Transaction starts when a node wishes to add/delete/ 286 relocate one or more cells to one of its neighbors. A 6P Transaction 287 ends when the cell(s) have been added/deleted/relocated from the 288 schedule of both nodes, or when the 6P Transaction has failed. 290 The 6P messages exchanged between nodes A and B during a 6P 291 Transaction SHOULD be exchanged on dedicated cells between A and B. 292 If no dedicated cells are scheduled between nodes A and B, shared 293 cells are be used. 295 Consistency between the schedules of the two neighbor nodes is of 296 utmost importance. A loss of consistency (e.g. node A has a transmit 297 cell to node B, but node B does not have the corresponding reception 298 cell) can cause loss of connectivity. To verify consistency, 299 neighbor nodes increment the "schedule generation" number of their 300 schedule each time their schedule is modified. Neighbor nodes 301 exchange the schedule generation number as part of each 6P 302 Transaction to detect possible inconsistencies. This mechanism is 303 explained in Section 4.4.7. 305 An implementation MUST include a mechanism to associate each 306 scheduled cell with the SF that scheduled it. This mechanism is 307 implementation-specific and out of the scope of this document. 309 A 6P Transaction can consist of 2 or 3 steps. An SF MUST specify 310 whether to use 2-step or 3-step transactions (or both). 312 We illustrate 2-step and 3-step transactions using the topology in 313 Figure 1. 315 4.1.1. 2-step 6P Transaction 317 Figure 4 shows an example 2-step 6P Transaction. Several elements 318 are left out to simplify understanding. 320 +----------+ +----------+ 321 | Node A | | Node B | 322 +----+-----+ +-----+----+ 323 | | 324 | 6P ADD Request | 325 | Type = REQUEST | 326 | Code = ADD | 327 | NumCells = 2 | 328 timeout | CellList = [(1,2),(2,2),(3,5)] | 329 --- |-------------------------------------->| 330 | | | 331 | | 6P Response | 332 | | Type = RESPONSE | 333 | | Code = SUCCESS | 334 | | CellList = [(2,2),(3,5)] | 335 X |<--------------------------------------| 336 | | 338 Figure 4: An example 2-step 6P Transaction. 340 In this example, the 2-step transaction occurs as follows: 342 1. The SF running on node A determines that 2 extra cells need to be 343 scheduled to node B. 344 2. The SF running on node A selects 3 candidate cells. 345 3. Node A sends a 6P ADD Request to node B, indicating it wishes to 346 add 2 cells (the "NumCells" value), and specifying the list of 3 347 candidate cells (the "CellList" value). Each cell in the 348 CellList is a (slotOffset,channelOffset) tuple. 349 4. When it sends the 6P ADD Request, Node A sets a timer to abort 350 the transaction if no response has been received before the 351 timeout. 352 5. The SF running on node B selects 2 out of the 3 cells in the 353 CellList of the 6P ADD Request. Node B sends back a 6P Response 354 to node A, indicating the cells that node B selected. 355 6. Upon completion of this 6P Transaction, 2 cells from A to B have 356 been added to the TSCH schedule of both nodes A and B. The 357 schedule generation number (see Section 4.4.7) is incremented to 358 allow inconsistency detection. 360 2-step transaction is used when node A selects the candidate cells. 362 4.1.2. 3-step 6P Transaction 364 Figure 5 shows an example 3-step 6P Transaction. Several elements 365 are left out to simplify understanding. 367 +----------+ +----------+ 368 | Node A | | Node B | 369 +----+-----+ +-----+----+ 370 | | 371 | 6P ADD Request | 372 | Type = REQUEST | 373 | Code = ADD | 374 | NumCells = 2 | 375 timeout | CellList = [] | 376 --- |-------------------------------------->| 377 | | | 378 | | 6P Response | 379 | | Type = RESPONSE | 380 | | Code = SUCCESS | 381 | | CellList = [(1,2),(2,2),(3,5)] | timeout 382 X |<--------------------------------------| --- 383 | | | 384 | 6P Confirmation | | 385 | Type = CONFIRMATION | | 386 | Code = SUCCESS | | 387 | CellList = [(2,2),(3,5)] | | 388 |-------------------------------------->| X 389 | | 391 Figure 5: An example 3-step 6P Transaction. 393 In this example, the 3-step transaction occurs as follows: 395 1. The SF running on node A determines that 2 extra cells need to be 396 scheduled to node B, but does not select candidate cells. 397 2. Node A sends a 6P ADD Request to node B, indicating it wishes to 398 add 2 cells (the "NumCells" value), with an empty "CellList". 399 3. When it sends the 6P ADD Request, Node A sets a timer to abort 400 the transaction if no response has been received before the 401 timeout. 402 4. The SF running on node B selects 3 candidate cells. Node B sends 403 back a 6P Response to node A, indicating the 3 cells it selected. 404 5. When it sends the 6P Response to node A, Node B sets a timer to 405 abort the transaction if no response has been received before the 406 timeout. 407 6. The SF running on node A selects 2 cells. Node A sends back a 6P 408 Confirmation to node B, indicating the cells it selected. 409 7. Upon completion of this 6P Transaction, 2 cells from A to B have 410 been added to the TSCH schedule of both nodes A and B. The 411 schedule generation number (see Section 4.4.7) is incremented to 412 allow inconsistencies detection. 414 3-step transaction is used when node B selects the candidate cells. 416 4.2. Message Format 418 4.2.1. 6top Information Element (IE) 420 6P messages are carried as payload of a 802.15.4 Payload Information 421 Element (IE) [IEEE802154-2015]. 6P messages travel over a single 422 hop. 424 This document defines the "6top IE", a subtype of the IETF IE defined 425 in [I-D.kivinen-802-15-ie], with subtype IANA_6TOP_SUBIE_ID. The 426 length of the 6top IE content is variable. 428 4.2.2. Generic 6P Message Format 430 All 6P messages follow the generic format shown in Figure 6. 432 1 2 3 433 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 1 434 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 435 |Version| T | R | Code | SFID | SeqNum| GEN | 436 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 437 | Other Fields... 438 +-+-+-+-+-+-+-+-+- 440 Figure 6: Generic 6P Message Format. 442 6P Version (Version): The version of the 6P protocol. Only version 443 0 is defined in this document. Future specifications MAY 444 define further versions of the 6P protocol. 445 Type (T): Type of message. The message types are defined in 446 Section 8.2.2. 447 Reserved (R): Reserved bits. These two bits SHOULD be set to zero 448 when sending the message and MUST be ignored upon reception. 449 Code: The Code field contains a 6P Command Identifier when the 6P 450 message is of Type REQUEST. Section 8.2.3 lists the 6P command 451 identifiers. The Code field contains a 6P Return Code when the 452 6P message is of Type RESPONSE or CONFIRMATION. Section 8.2.4 453 lists the 6P Return Codes. The same Return Codes are used in 454 both 6P Response and 6P Confirmation messages. 455 6top Scheduling Function Identifier (SFID): The identifier of the SF 456 to use to handle this message. The SFID is defined in 457 Section 5.1. 458 SeqNum: Sequence number associated with the 6P Transaction, used to 459 match the 6P Request, 6P Response and 6P Confirmation of the 460 same 6P Transaction. The value of SeqNum MUST increment by 461 exactly one at each new 6P request issued to the same neighbor. 463 Schedule Generation (GEN): Schedule Generation for the transactions 464 between node A and node B. The generation is used to ensure 465 consistency between the schedules of the two neighbors. 466 Section 4.4.7 details how the schedule generation is managed. 467 Other Fields: The list of other fields depends on the type of 468 messages, and is detailed in Section 4.3. 470 4.2.3. 6P CellOptions 472 An 8-bit 6P CellOptions bitmap is present in the following 6P 473 requests: ADD, DELETE, COUNT, LIST, RELOCATE. 475 o In the 6P ADD request, the 6P CellOptions bitmap is used to 476 specify what type of cell to add. 477 o In the 6P DELETE request, the 6P CellOptions bitmap is used to 478 specify what type of cell to delete. 479 o In the 6P COUNT and the 6P LIST requests, the 6P CellOptions 480 bitmap is used as a selector of a particular type of cells. 481 o In the 6P RELOCATE request, the 6P CellOptions bitmap is used to 482 specify what type of cell to relocate. 484 The contents of the 6P CellOptions bitmap apply to all elements in 485 the CellList field. Section 8.2.6 contains the RECOMMENDED format of 486 the 6P CellOptions bitmap. Figure 7 contains the RECOMMENDED meaning 487 of the 6P CellOptions bitmap for the 6P COUNT and 6P LIST requests. 489 Note: assuming node A issues the 6P command to node B. 490 +-------------+-----------------------------------------------+ 491 | CellOptions | cells scheduled with A that are to be selected| 492 | Value | by B when receiving a 6P message from A | 493 +-------------+-----------------------------------------------+ 494 |TX=0,RX=0,S=0| select all cells | 495 +-------------+-----------------------------------------------+ 496 |TX=1,RX=0,S=0| select the cells scheduled marked as RX | 497 +-------------+-----------------------------------------------+ 498 |TX=0,RX=1,S=0| select the cells marked as TX | 499 +-------------+-----------------------------------------------+ 500 |TX=1,RX=1,S=0| select the cells marked as TX and RX | 501 +-------------+-----------------------------------------------+ 502 |TX=0,RX=0,S=1| select the cells marked as SHARE | 503 +-------------+-----------------------------------------------+ 504 |TX=1,RX=0,S=1| select the cells marked as RX and SHARE | 505 +-------------+-----------------------------------------------+ 506 |TX=0,RX=1,S=1| select the cells marked as TX and SHARE | 507 +-------------+-----------------------------------------------+ 508 |TX=1,RX=1,S=1| select the cells marked as TX and RX and SHARE| 509 +-------------+-----------------------------------------------+ 511 Figure 7: Meaning of the 6P CellOptions bitmap for the 6P COUNT and 512 the 6P LIST requests. 514 The CellOptions is an opaque set of bits, sent unmodified to the SF. 515 The SF MAY redefine the format of the CellOptions bitmap. The SF MAY 516 redefine the meaning of the CellOptions bitmap. 518 4.2.4. 6P CellList 520 A CellList field MAY be present in a 6P ADD Request, a 6P DELETE 521 Request, a 6P RELOCATE Request, a 6P Response or a 6P Confirmation. 522 It is composed of zero, one or more 6P Cell containers. The contents 523 of the CellOptions field specify the options associated with all 524 cells in the CellList. This necessarily means that the same options 525 are associated with all cells in the CellList. 527 The 6P Cell is a 4-byte field, its RECOMMENDED format is: 529 1 2 3 530 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 1 531 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 532 | slotOffset | channelOffset | 533 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 535 Figure 8: 6P Cell Format. 537 slotOffset: The slot offset of the cell. 538 channelOffset: The channel offset of the cell. 540 The CellList is an opaque set of bytes, sent unmodified to the SF. 541 The SF MAY redefine the format of the CellList field. 543 4.3. 6P Commands and Operations 545 4.3.1. Adding Cells 547 Cells are added by using the 6P ADD command. The Type field (T) is 548 set to REQUEST. The Code field is set to ADD. Figure 9 defines the 549 format of a 6P ADD Request. 551 1 2 3 552 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 1 553 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 554 |Version| T | R | Code | SFID | SeqNum| GEN | 555 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 556 | Metadata | CellOptions | NumCells | 557 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 558 | CellList ... 559 +-+-+-+-+-+-+-+-+- 561 Figure 9: 6P ADD Request Format. 563 Metadata: Used as extra signaling to the SF. The contents of the 564 Metadata field is an opaque set of bytes passed unmodified to 565 the SF. The meaning of this field depends on the SF, and is 566 out of scope of this document. For example, Metadata could 567 specify which slotframe to be used for scheduling the cells. 568 CellOptions: Indicates the options to associate with the cells to be 569 added. If more than one cell is added (NumCells>1), the same 570 options are associated with all of them. This necessarily 571 means that, if node A needs to add multiple cells with 572 different options, it needs to issue multiple 6P ADD 573 Transactions. 574 NumCells: The number of additional cells the sender wants to 575 schedule to the receiver. 576 CellList: A list of 0, 1 or multiple 6P Cells to be added. 578 Figure 10 defines the format of a 6P ADD Response and Confirmation. 580 1 2 3 581 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 1 582 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 583 |Version| T | R | Code | SFID | SeqNum| GEN | 584 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 585 | CellList ... 586 +-+-+-+-+-+-+-+-+- 588 Figure 10: 6P ADD Response and Confirmation Formats. 590 CellList: A list of 0, 1 or multiple 6P Cells. 592 Consider the topology in Figure 1 where the SF on node A decides to 593 add NumCells cells to node B. 595 Node A's SF selects NumCandidate cells from its schedule as candidate 596 cells to node B. The CellOptions field specifies the type of these 597 cells. NumCandidate MUST be larger or equal to NumCells. How many 598 cells it selects (NumCandidate) and how that selection is done is 599 specified in the SF and out of scope of this document. Node A sends 600 a 6P ADD Request to node B which contains the CellOptions, the value 601 of NumCells and a selection of NumCandidate cells in the CellList. 602 In case the NumCandidate cells do not fit in a single packet, this 603 operation MUST be split in multiple independent 6P ADD Requests, each 604 for a subset of the number of cells that eventually need to be added. 606 Upon receiving the request, node B's SF verifies which of the cells 607 in the CellList it can install in node B's schedule following the 608 specified CellOptions field. How that selection is done is specified 609 in the SF and out of scope of this document. The verification can 610 succeed (NumCells cells from the CellList can be used), fail (none of 611 the cells from the CellList can be used) or partially succeed (less 612 than NumCells cells from the CellList can be used). In all cases, 613 node B MUST send a 6P Response with return code set to SUCCESS, and 614 which specifies the list of cells that were scheduled following the 615 CellOptions field. That can contain 0 elements (when the 616 verification failed), NumCells elements (succeeded) or between 0 and 617 NumCells elements (partially succeeded). 619 Upon receiving the response, node A adds the cells specified in the 620 CellList according to the request CellOptions field. 622 4.3.2. Deleting Cells 624 Cells are deleted by using the 6P DELETE command. The Type field (T) 625 is set to REQUEST. The Code field is set to DELETE. Figure 11 626 defines the format of a 6P DELETE Request. 628 1 2 3 629 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 1 630 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 631 |Version| T | R | Code | SFID | SeqNum| GEN | 632 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 633 | Metadata | CellOptions | NumCells | 634 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 635 | CellList ... 636 +-+-+-+-+-+-+-+-+- 638 Figure 11: 6P DELETE Request Format. 640 Metadata: Same usage as for the 6P ADD command, see Section 4.3.1. 641 Its format is same as that in 6P ADD command, but content could 642 be different. 643 CellOptions: Indicates the options that need to be associated to the 644 cells to delete. Only the cells matching the CellOptions are 645 deleted. 646 NumCells: The number of cells from the specified CellList the sender 647 wants to delete from the schedule of both sender and receiver. 648 CellList: A list of 0, 1 or multiple 6P Cells. 650 Figure 12 defines the format of a 6P DELETE Response and 651 Confirmation. 653 1 2 3 654 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 1 655 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 656 |Version| T | R | Code | SFID | SeqNum| GEN | 657 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 658 | CellList ... 659 +-+-+-+-+-+-+-+-+- 661 Figure 12: 6P DELETE Response and Confirmation Formats. 663 CellList: A list of 0, 1 or multiple 6P Cells. 665 The behavior for deleting cells is equivalent to that of adding cells 666 except that: 668 o The nodes delete the cells they agree upon rather than adding 669 them. 670 o All cells in the CellList MUST already be scheduled between the 671 two nodes and must match the CellOptions field. If node A puts 672 cells in its CellList that are not already scheduled between the 673 two nodes and match the CellOptions field, node B replies with a 674 CELLLIST_ERR return code. 676 o If the CellList in the 6P Request is empty, the SF on the 677 receiving node is free to delete any cell from the sender, as long 678 as it matches the CellOptions field. 679 o The CellList in a 6P Request (2-step transaction) or 6P Response 680 (3-step transaction) MUST either be empty, contain exactly 681 NumCells cells, or more than NumCells cells. The case where the 682 CellList is not empty but contains less than NumCells cells is not 683 supported. 685 4.3.3. Relocating Cells 687 Cell relocation consists in moving a cell to a different 688 [slotOffset,channelOffset] location in the schedule. The Type field 689 (T) is set to REQUEST. The Code is set to RELOCATE. Figure 13 690 defines the format of a 6P RELOCATE Request. 692 1 2 3 693 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 1 694 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 695 |Version| T | R | Code | SFID | SeqNum| GEN | 696 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 697 | Metadata | CellOptions | NumCells | 698 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 699 | Rel. CellList ... |Cand. CellList (Optional) ... 700 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 702 Figure 13: 6P RELOCATE Request Format. 704 Metadata: Same usage as for the 6P ADD command, see Section 4.3.1. 705 Its format is same as that in 6P ADD command, but content could 706 be different. 707 CellOptions: Indicates the options that need to be associated to the 708 relocated cells. 709 NumCells: The number of cells to relocate, which MUST be equal or 710 greater than 1. 711 Relocation CellList: The list of NumCells 6P Cells to relocate. 712 Candidate CellList: A list of NumCandidate candidate cells for node 713 B to pick from. NumCandidate MUST be equal or greater than 714 NumCells. 716 Figure 14 defines the format of a 6P RELOCATE Response and 717 Confirmation. 719 1 2 3 720 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 1 721 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 722 |Version| T | R | Code | SFID | SeqNum| GEN | 723 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 724 | CellList ... 725 +-+-+-+-+-+-+-+-+- 727 Figure 14: 6P RELOCATE Response and Confirmation Formats. 729 CellList: A list of 0, 1 or multiple 6P Cells. 731 Node A's SF wants to relocate NumCells cells. Node A creates a 6P 732 RELOCATE Request, and indicates the cells to relocate in the 733 Relocation CellList. It also selects NumCandidate cells from its 734 schedule as candidate cells for node B, and puts those in the 735 Candidate CellList. The CellOptions field specifies the type of the 736 cell(s) to relocate. NumCandidate MUST be larger or equal to 737 NumCells. How many cells it selects (NumCandidate) and how that 738 selection is done is specified in the SF and out of scope of this 739 document. Node A sends the 6P RELOCATE Request to node B. 741 Upon receiving the request, node B's SF verifies that all the cells 742 in the Relocation CellList are indeed scheduled with node A, and are 743 associate the options specified in the CellOptions field. If that 744 check fails, node B MUST send a 6P Response to node A with return 745 code CELLLIST_ERR. If that check passes, node B's SF verifies which 746 of the cells in the Candidate CellList it can install in its 747 schedule. How that selection is done is specified in the SF and out 748 of scope of this document. That verification on Candidate CellList 749 can succeed (NumCells cells from the Candidate CellList can be used), 750 fail (none of the cells from the Candidate CellList can be used) or 751 partially succeed (less than NumCells cells from the Candidate 752 CellList can be used). In all cases, node B MUST send a 6P Response 753 with return code set to SUCCESS, and which specifies the list of 754 cells that were scheduled following the CellOptions field. That can 755 contain 0 elements (when the verification failed), NumCells elements 756 (succeeded) or between 0 and NumCells elements (partially succeeded). 757 If N < NumCells cells appear in the CellList, this means first N 758 cells in the Relocation CellList have been relocated, the remainder 759 have not. 761 Upon receiving the response, node A relocates the cells specified in 762 Relocation CellList of its RELOCATE Request to the new location 763 specified in the CellList of the 6P Response. 765 +----------+ +----------+ 766 | Node A | | Node B | 767 +----+-----+ +-----+----+ 768 | | 769 | 6P RELOCATE Request | 770 | Type = REQUEST | 771 | Code = RELOCATE | 772 | NumCells = 2 | 773 | R.CellList = [(1,2),(2,2)] | 774 | C.CellList = [(3,2),(4,2),(6,5)] | 775 |-------------------------------------->| B relocates 776 | | (1,2)->(4,2) 777 | 6P Response | but cannot 778 | Type = RESPONSE | relocate (2,2) 779 | Code = SUCCESS | 780 | CellList = [(4,2)] | 781 A relocates |<--------------------------------------| 782 (1,2)->(4,2)| | 784 Figure 15: 6P RELOCATE Example. 786 4.3.4. Counting Cells 788 To retrieve the number of scheduled cells at B, node A issues a 6P 789 COUNT command. The Type field (T) is set to REQUEST. The Code field 790 is set to COUNT. Figure 16 defines the format of a 6P COUNT Request. 792 1 2 793 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 1 794 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 795 |Version| T | R | Code | SFID | SeqNum| GEN | 796 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 797 | Metadata | CellOptions | 798 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 800 Figure 16: 6P COUNT Request Format. 802 Metadata: Same usage as for the 6P ADD command, see Section 4.3.1. 803 Its format is same as that in 6P ADD command, but content could 804 be different. 805 CellOptions: Specifies which types of cells to be counted. 807 Figure 17 defines the format of a 6P COUNT Response. 809 1 2 3 810 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 1 811 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 812 |Version| T | R | Code | SFID | SeqNum| GEN | 813 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 814 | NumCells | 815 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 817 Figure 17: 6P COUNT Response Format. 819 NumCells: The number of cells which correspond to the fields of the 820 request. 822 Node A issues a COUNT command to node B, specifying a set of cell 823 options. Upon receiving the 6P COUNT request, node B goes through 824 its schedule and counts the number of cells scheduled with node A in 825 its own schedule, and which match the cell options in the CellOptions 826 field of the request. Section 4.2.3 details the use of the 827 CellOptions field. 829 Node B issues a 6P response to node A with return code set to 830 SUCCESS, and with NumCells containing the number of cells that match 831 the request. 833 4.3.5. Listing Cells 835 To retrieve the list of scheduled cells at B, node A issues a 6P LIST 836 command. The Type field (T) is set to REQUEST. The Code field is 837 set to LIST. Figure 18 defines the format of a 6P LIST Request. 839 1 2 840 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 1 841 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 842 |Version| T | R | Code | SFID | SeqNum| GEN | 843 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 844 | Metadata | CellOptions | Reserved | 845 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 846 | Offset | MaxNumCells | 847 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 849 Figure 18: 6P LIST Request Format. 851 Metadata: Same usage as for the 6P ADD command, see Section 4.3.1. 852 Its format is same as that in 6P ADD command, but content could 853 be different. 854 CellOptions: Specifies which types of cells to be listed. 855 Reserved: Set to 0. 857 Offset: The Offset of the first scheduled cell that is requested. 858 The mechanism assumes cells are ordered according to a rule 859 defined in the SF. The rule MUST always order the cells in the 860 same way. 861 MaxNumCells: The maximum number of cells to be listed. Node B MAY 862 returns less than MaxNumCells cells, for example if MaxNumCells 863 cells do not fit in the frame. 865 Figure 19 defines the format of a 6P LIST Response. 867 1 2 3 868 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 1 869 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 870 |Version| T | R | Code | SFID | SeqNum| GEN | 871 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 872 | CellList ... 873 +-+-+-+-+-+-+-+-+- 875 Figure 19: 6P LIST Response Format. 877 CellList: A list of 0, 1 or multiple 6P Cells. 879 When receiving a LIST command, node B returns the cells in its 880 schedule that match the CellOptions field as specified in 881 Section 4.2.3 883 When node B receives a LIST request, the returned CellList in the 6P 884 Response contains between 1 and MaxNumCells cells, starting from the 885 specified offset. Node B SHOULD include as many cells as fit in the 886 frame. If the response contains the last cell, Node B MUST set the 887 Code field in the response to EOL, indicating to Node A that there no 888 more cells that match the request. Node B MUST return at least one 889 cell, unless the specified Offset is beyond the end of B's cell list 890 in its schedule. If node B has less than Offset cells that match the 891 request, node B returns an empty CellList and a Code field set to 892 EOL. 894 4.3.6. Clearing the Schedule 896 To clear the schedule between nodes A and B (for example after a 897 schedule inconsistency is detected), node A issues a CLEAR command. 898 The Type field (T) is set to 6P Request. The Code field is set to 899 CLEAR. Figure 20 defines the format of a 6P CLEAR Request. 901 1 2 902 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 1 903 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 904 |Version| T | R | Code | SFID | SeqNum| GEN | 905 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 906 | Metadata | 907 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 909 Figure 20: 6P CLEAR Request Format. 911 Metadata: Same usage as for the 6P ADD command, see Section 4.3.1. 912 Its format is same as that in 6P ADD command, but content could 913 be different. 915 Figure 21 defines the format of a 6P CLEAR Response. 917 1 2 3 918 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 1 919 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 920 |Version| T | R | Code | SFID | SeqNum| GEN | 921 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 923 Figure 21: 6P CLEAR Response Format. 925 When a 6P CLEAR command is issued from node A to node B, both nodes A 926 and B MUST remove all the cells scheduled between them. That is, 927 node A MUST remove all the cells scheduled with B, and node B MUST 928 remove all the cells scheduled with A. In a 6P CLEAR command, the 929 generation counter GEN MUST NOT be checked. That is, its value is 930 "don't care". In particular, even if the request contains a GEN 931 value that would normally cause node B to detect a schedule 932 generation mismatch, the transaction MUST NOT be aborted. 934 4.4. Protocol Functional Details 936 4.4.1. Version Checking 938 All messages contain a Version field. If multiple Versions of the 6P 939 protocol have been defined (in future specifications for Version 940 values different from 0), a node MAY implement multiple protocol 941 versions at the same time. When receiving a 6P message with a 942 Version number it does not implement, a node MUST reply with a 6P 943 Response with a Return Code field set to VER_ERR. The Version field 944 in the 6P Response MUST be the same as the Version field in the 945 corresponding 6P Request. In a 3-step transaction, the Version field 946 in the 6P Confirmation MUST match that of the 6P Request and 6P 947 Response in the same transaction. 949 4.4.2. SFID Checking 951 All messages contain a SFID field. A node MAY support multiple SFs 952 at the same time. When receiving a 6P message with an unsupported 953 SFID, a node MUST reply with a 6P Response and a return code of 954 SFID_ERR. The SFID field in the 6P Response MUST be the same as the 955 SFID field in the corresponding 6P Request. In a 3-step transaction, 956 the SFID field in the 6P Confirmation MUST match that of the 6P 957 Request and 6P Response in the same transaction. 959 4.4.3. Concurrent 6P Transactions 961 Only a single 6P Transaction between two neighbors, in a given 962 direction, can take place at the same time. That is, a node MUST NOT 963 issue a new 6P Request to a given neighbor before having received the 964 6P Response for a previous request to that neighbor, except when the 965 previous 6P Transaction has timed out. If a node receives a 6P 966 Request from a given neighbor before having sent the 6P Response to 967 the previous 6P Request from that neighbor, it MUST send back a 6P 968 Response with a return code of RESET. A node receiving RESET code 969 MUST abort the transaction and consider it never happened. 971 Nodes A and B MAY support having two transactions going on at the 972 same time, one in each direction. Similarly, a node MAY support 973 concurrent 6P Transactions from different neighbors. In this case, 974 the cells involved in an ongoing 6P Transaction MUST be locked until 975 the transaction finishes. For example, in Figure 1, node C can have 976 a different ongoing 6P Transaction with nodes B and R. In case a 977 node does not have enough resources to handle concurrent 6P 978 Transactions from different neighbors it MUST reply with a 6P 979 Response with return code NORES. In case the requested cells are 980 locked, it MUST reply to that request with a 6P Response with return 981 code BUSY. The node receiving BUSY or an NORES MAY implement a retry 982 mechanism, defined by the SF. 984 4.4.4. Timeout 986 A timeout occurs when the node sending the 6P Request has not 987 received the 6P Response within a specified amount of time determined 988 by the SF. In a 3-step transaction, a timeout also occurs when the 989 node sending the 6P Response has not received the 6P Confirmation. 990 The timeout should be longer than the longest possible time it can 991 take for the exchange to finish. The value of the timeout hence 992 depends on the number of cells scheduled between the neighbor nodes, 993 the maximum number of link-layer retransmissions, etc. The SF MUST 994 determine the value of the timeout. The value of the timeout is out 995 of scope of this document. 997 4.4.5. SeqNum Mismatch 999 A SeqNum mismatch happens when a node receives a 6P Response or 6P 1000 Confirmation with SeqNum value different from the SeqNum value in the 1001 6P Request. When it detects a SeqNum mismatch, the node MUST drop 1002 the packet and consider the 6P Transaction as having failed. 1004 4.4.6. Aborting a 6P Transaction 1006 In case the receiver of a 6P Request fails during a 6P Transaction 1007 and is unable to complete it, it SHOULD reply to that Request with a 1008 6P Response with return code RESET. Upon receiving this 6P Response, 1009 the initiator of the 6P Transaction MUST consider the 6P Transaction 1010 as failed. 1012 Similarly, in the case of 3-step transaction, when the receiver of a 1013 6P Response fails during the 6P Transaction and is unable to complete 1014 it, it SHOULD reply to that 6P Response with a 6P Confirmation with 1015 return code RESET. Upon receiving this 6P Confirmation, the sender 1016 of the 6P Response MUST consider the 6P Transaction as failed. 1018 4.4.7. Generation Management 1020 For each neighbor, a node maintains a 4-bit generation number. The 1021 generation number counts the number of transactions that have 1022 modified the schedule with the particular neighbor so far. This 1023 number is a variable internal to the node. 1025 4.4.7.1. Incrementing the Generation Number 1027 The generation number is incremented as a 4-bit lollipop counter. 1028 Its possible values are: 1030 +---------+---------------------------+ 1031 | Value | Meaning | 1032 +---------+---------------------------+ 1033 | 0x0 | Clear or never scheduled | 1034 | 0x1-0x9 | Lollipop Counter values | 1035 | 0xa-0xf | Reserved | 1036 +---------+---------------------------+ 1038 Figure 22: Possible values of the generation number. 1040 The generation number is set to 0 upon initialization, and after a 6P 1041 CLEAR command. The generation number is incremented by exactly 1 1042 each time a cell with that neighbor is added/deleted/relocated from 1043 the schedule (e.g. after a successful 6P ADD, 6P DELETE or 6P 1044 RELOCATE transaction). The value rolls from 0x9 to 0x1 (i.e. not 1045 0x0). This results in a lollipop counter with 0x0 the start value, 1046 and 0x1-0x9 the count values. Values from 0xa to 0xf are reserved 1047 and MUST NOT be used. 1049 4.4.7.2. Setting GEN field in the 6P Message Header 1051 Each 6P message contains a GEN field, used to indicate the current 1052 generation number of the node transmitting the message. The value of 1053 the GEN field MUST be set according to the following rules: 1055 o When node A sends a 6P Request or 6P Confirmation to node B, node 1056 A sets GEN to its generation number for Node B. 1057 o When node B sends a 6P Response to node A, node B sets GEN to its 1058 generation number for node A. 1060 4.4.7.3. Detecting and Handling Schedule Generation Inconsistencies 1062 Upon receiving a 6P message, a node MUST do the following checks: 1064 o When node B receives a 6P Request or 6P Confirmation from node A, 1065 it verifies that the value of the GEN field in the 6P message is 1066 equal to its internal generation number. 1067 o When node A receives a 6P Response from node B, it verifies that 1068 the value of the GEN field in the 6P message is equal to its 1069 internal generation number. 1071 If any of these comparisons is false, the node has detected a 1072 schedule generation inconsistency. 1074 When a schedule generation inconsistency is detected: 1076 o If the code of the 6P Request is different from CLEAR, the node 1077 MUST reply with error code GEN_ERR. 1078 o If the code of the 6P Request is CLEAR, the schedule generation 1079 inconsistency MUST be ignored. 1081 It is up to the Scheduling Function to define the action to take when 1082 an schedule generation inconsistency is detected. The RECOMMENDED 1083 action is to issue a 6P CLEAR command. 1085 4.4.8. Handling Error Responses 1087 A return code marked as YES in the "Is Error" column in Figure 27 1088 indicates an error. When a node receives a 6P Response or 6P 1089 Confirmation with such an error, it MUST consider the 6P Transaction 1090 failed. In particular, if this was a response to a 6P ADD/DELETE/ 1091 RELOCATE Request, the node MUST NOT add/delete/relocate any of the 1092 cells involved in this 6P Transaction. Similarly, a node sending a 1093 6P Response or a 6P Confirmation with an error code MUST NOT 1094 add/delete/relocate any cells as part of that 6P Transaction. 1095 Defining what to do after an error has occurred is out of scope of 1096 this document. The SF defines what to do after an error has 1097 occurred. 1099 4.5. Security 1101 6P messages are secured through link-layer security. When link-layer 1102 security is enabled, the 6P messages MUST be secured. This is 1103 possible because 6P messages are carried as Payload IE. 1105 5. Guidelines for 6top Scheduling Functions (SF) 1107 5.1. SF Identifier (SFID) 1109 Each SF has a 1-byte identifier. Section 8.2.5 defines the rules for 1110 applying for an SFID. 1112 5.2. Requirements for an SF 1114 The specification for an SF 1116 o MUST specify an identifier for that SF. 1117 o MUST specify the rule for a node to decide when to add/delete one 1118 or more cells to a neighbor. 1119 o MUST specify the rule for a Transaction source to select cells to 1120 add to the CellList field in the 6P ADD Request. 1121 o MUST specify the rule for a Transaction destination to select 1122 cells from CellList to add to its schedule. 1123 o MUST specify a value for the 6P Timeout, or a rule/equation to 1124 calculate it. 1125 o MUST specify the rule for ordering cells. 1126 o MUST specify a meaning for the "Metadata" field in the 6P ADD 1127 Request. 1128 o MUST specify the SF behavior of a node when it boots. 1129 o MUST specify what to do after an error has occurred (either the 1130 node sent a 6P Response with an error code, or received one). 1131 o MUST specify the list of statistics to gather. An example 1132 statistic is the number of transmitted frames to each neighbor. 1133 In case the SF requires no statistics to be gathered, the specific 1134 of the SF MUST explicitly state so. 1136 o SHOULD clearly state the application domain the SF is created for. 1137 o SHOULD contain examples which highlight normal and error 1138 scenarios. 1139 o SHOULD contain a list of current implementations, at least during 1140 the I-D state of the document, per [RFC6982]. 1142 o SHOULD contain a performance evaluation of the scheme, possibly 1143 through references to external documents. 1145 o MAY redefine the format of the CellList field. 1146 o MAY redefine the format of the CellOptions field. 1147 o MAY redefine the meaning of the CellOptions field. 1149 5.3. Recommended Structure of an SF Specification 1151 The following section structure for a SF document is RECOMMENDED: 1153 o Introduction 1154 o Scheduling Function Identifier 1155 o Rules for Adding/Deleting Cells 1156 o Rules for CellList 1157 o 6P Timeout Value 1158 o Rule for Ordering Cells 1159 o Meaning of the Metadata Field 1160 o Node Behavior at Boot 1161 o 6P Error Handling 1162 o Examples 1163 o Implementation Status 1164 o Security Considerations 1165 o IANA Considerations 1167 6. Implementation Status 1169 This section records the status of known implementations of the 1170 protocol defined by this specification at the time of posting of this 1171 Internet-Draft, and is based on a proposal described in [RFC6982]. 1172 The description of implementations in this section is intended to 1173 assist the IETF in its decision processes in progressing drafts to 1174 RFCs. Please note that the listing of any individual implementation 1175 here does not imply endorsement by the IETF. Furthermore, no effort 1176 has been spent to verify the information presented here that was 1177 supplied by IETF contributors. This is not intended as, and must not 1178 be construed to be, a catalog of available implementations or their 1179 features. Readers are advised to note that other implementations may 1180 exist. 1182 According to [RFC6982], "this will allow reviewers and working groups 1183 to assign due consideration to documents that have the benefit of 1184 running code, which may serve as evidence of valuable experimentation 1185 and feedback that have made the implemented protocols more mature. 1186 It is up to the individual working groups to use this information as 1187 they see fit". 1189 ETSI 6TiSCH/6lo plugtests: 6P was one of the protocols addressed 1190 during the ETSI 6TiSCH #3 plugtests organized on 15-17 July 2016 1191 in Berlin, Germany. 15 entities participated in this event, 1192 verifying the compliance and interoperability of their 1193 implementation of 6P. This event happened under NDA, so neither 1194 the name of the entities nor the test results are public. This 1195 event is, however, a clear indication of the maturity of 6P, and 1196 the interest it generates. More information about the event at 1197 http://www.etsi.org/news-events/events/1077-6tisch-6lo-plugtests. 1198 ETSI 6TiSCH #2 plugtests: 6P was one of two protocols addressed 1199 during the ETSI 6TiSCH #2 plugtests organized on 2-4 February 2016 1200 in Paris, France. 14 entities participated in this event, 1201 verifying the compliance and interoperability of their 1202 implementation of 6P. This event happened under NDA, so neither 1203 the name of the entities nor the test results are public. This 1204 event is, however, a clear indication of the maturity of 6P, and 1205 the interest it generates. More information about the event at 1206 http://www.etsi.org/news-events/events/1022-6TiSCH-2-plugtests. 1207 OpenWSN: 6P is implemented in the OpenWSN project [OpenWSN] under a 1208 BSD open-source license. The authors of this document are 1209 collaborating with the OpenWSN community to gather feedback about 1210 the status and performance of the protocols described in this 1211 document. Results from that discussion will appear in this 1212 section in future revision of this specification. More 1213 information about this implementation at http://www.openwsn.org/. 1214 Wireshark Dissector: A Wireshark dissector for 6P is implemented 1215 under a BSD open-source license. It is developed and maintained 1216 at https://github.com/openwsn-berkeley/dissectors/, and regularly 1217 merged into the main Wireshark repository. Please see the 1218 Wireshark documentation to see what version of 6P it supports. 1220 7. Security Considerations 1222 6P messages are carried inside 802.15.4 Payload Information Elements 1223 (IEs). Those Payload IEs are encrypted and authenticated at the link 1224 layer through CCM*. 6P benefits from the same level of security as 1225 any other Payload IE. The 6P protocol does not define its own 1226 security mechanisms. A key management solution is out of scope for 1227 this document. The 6P protocol will benefit for the key management 1228 solution used in the network. 1230 8. IANA Considerations 1232 8.1. IETF IE Subtype '6P' 1234 This document adds the following number to the "IEEE Std 802.15.4 1235 IETF IE subtype IDs" registry defined by [I-D.kivinen-802-15-ie]: 1237 +--------------------+------+-----------+ 1238 | Subtype | Name | Reference | 1239 +--------------------+------+-----------+ 1240 | IANA_6TOP_SUBIE_ID | 6P | RFCXXXX | 1241 +--------------------+------+-----------+ 1243 Figure 23: IETF IE Subtype '6P'. 1245 8.2. 6TiSCH parameters sub-registries 1247 This section defines sub-registries within the "IPv6 over the TSCH 1248 mode of IEEE 802.15.4e (6TiSCH) parameters" registry, hereafter 1249 referred to as the "6TiSCH parameters" registry. Each sub-registry 1250 is described in a subsection. 1252 8.2.1. 6P Version Numbers 1254 The name of the sub-registry is "CoAP Version Numbers". 1256 A Note included in this registry should say: "In the 6top Protocol 1257 (6P) [RFCXXXX] there is a field to identify the version of the 1258 protocol. This field is 4 bits in size." 1260 Each entry in the sub-registry must include the Version in the range 1261 0-15, and a reference to the 6P version's documentation. 1263 The initial entry in this sub-registry is as follows: 1265 +---------+------------+ 1266 | Version | Reference | 1267 +---------+------------+ 1268 | 0 | RFCXXXX | 1269 +---------+------------+ 1271 Figure 24: 6P Version Numbers. 1273 All other Version Numbers are Unassigned. 1275 The IANA policy for future additions to this sub-registry is "IETF 1276 Review or IESG Approval" as described in [RFC5226]. 1278 8.2.2. 6P Message Types 1280 The name of the sub-registry is "6P Message Types". 1282 A Note included in this registry should say: "In the 6top Protocol 1283 (6P) version 0 [RFCXXXX], there is a field to identify the type of 1284 message. This field is 2 bits in size." 1285 Each entry in the sub-registry must include the Type in the range 1286 b00-b11, the corresponding Name, and a reference to the 6P message 1287 type's documentation. 1289 Initial entries in this sub-registry are as follows: 1291 +------+--------------+-----------+ 1292 | Type | Name | Reference | 1293 +------+--------------+-----------+ 1294 | b00 | REQUEST | RFCXXXX | 1295 | b01 | RESPONSE | RFCXXXX | 1296 | b10 | CONFIRMATION | RFCXXXX | 1297 +------+--------------+-----------+ 1299 Figure 25: 6P Message Types. 1301 All other Message Types are Reserved. 1303 The IANA policy for future additions to this sub-registry is "IETF 1304 Review or IESG Approval" as described in [RFC5226]. 1306 8.2.3. 6P Command Identifiers 1308 The name of the sub-registry is "6P Command Identifiers". 1310 A Note included in this registry should say: "In the 6top Protocol 1311 (6P) version 0 [RFCXXXX], there is a Code field which is 8 bits in 1312 size. In a 6P Request, the value of this Code field is used to 1313 identify the command." 1315 Each entry in the sub-registry must include the Identifier in the 1316 range 0-255, the corresponding Name, and a reference to the 6P 1317 command identifier's documentation. 1319 Initial entries in this sub-registry are as follows: 1321 +------------+------------+-----------+ 1322 | Identifier | Name | Reference | 1323 +------------+------------+-----------+ 1324 | 0 | Reserved | | 1325 | 1 | ADD | RFCXXXX | 1326 | 2 | DELETE | RFCXXXX | 1327 | 3 | RELOCATE | RFCXXXX | 1328 | 4 | COUNT | RFCXXXX | 1329 | 5 | LIST | RFCXXXX | 1330 | 6 | CLEAR | RFCXXXX | 1331 | 7-254 | Unassigned | | 1332 | 255 | Reserved | | 1333 +------------+------------+-----------+ 1335 Figure 26: 6P Command Identifiers. 1337 The IANA policy for future additions to this sub-registry is "IETF 1338 Review or IESG Approval" as described in [RFC5226]. 1340 8.2.4. 6P Return Codes 1342 The name of the sub-registry is "6P Return Codes". 1344 A Note included in this registry should say: "In the 6top Protocol 1345 (6P) version 0 [RFCXXXX], there is a Code field which is 8 bits in 1346 size. In a 6P Response or 6P Confirmation, the value of this Code 1347 field is used to identify the return code." 1349 Each entry in the sub-registry must include the Code in the range 1350 0-255, the corresponding Name, the corresponding Description, and a 1351 reference to the 6P return code's documentation. 1353 Initial entries in this sub-registry are as follows: 1355 +--------+-------------+---------------------------+-----------+ 1356 | Code | Name | Description | Is Error? | 1357 +--------+-------------+---------------------------+-----------+ 1358 | 0 | SUCCESS | operation succeeded | No | 1359 | 1 | ERROR | generic error | Yes | 1360 | 2 | EOL | end of list | No | 1361 | 3 | RESET | critical error, reset | Yes | 1362 | 4 | VER_ERR | unsupported 6P version | Yes | 1363 | 5 | SFID_ERR | unsupported SFID | Yes | 1364 | 6 | GEN_ERR | wrong schedule generation | Yes | 1365 | 7 | BUSY | busy | Yes | 1366 | 8 | NORES | not enough resources | Yes | 1367 | 9 | CELLLIST_ERR| cellList error | Yes | 1368 +--------+-------------+---------------------------+-----------+ 1370 Figure 27: 6P Return Codes. 1372 All other Message Types are Unassigned. 1374 The IANA policy for future additions to this sub-registry is "IETF 1375 Review or IESG Approval" as described in [RFC5226]. 1377 8.2.5. 6P Scheduling Function Identifiers 1379 6P Scheduling Function Identifiers. 1381 A Note included in this registry should say: "In the 6top Protocol 1382 (6P) version 0 [RFCXXXX], there is a field to identify the scheduling 1383 function to handle the message. This field is 8 bits in size." 1385 Each entry in the sub-registry must include the SFID in the range 1386 0-255, the corresponding Name, and a reference to the 6P Scheduling 1387 Function's documentation. 1389 The initial entry in this sub-registry is as follows: 1391 +-------+--------------------------+----------------------------+ 1392 | SFID | Name | Reference | 1393 +-------+--------------------------+----------------------------+ 1394 | 0 | Scheduling Function Zero | draft-ietf-6tisch-6top-sf0 | 1395 +-------+--------------------------+----------------------------+ 1397 Figure 28: SF Identifiers (SFID). 1399 All other Message Types are Unassigned. 1401 The IANA policy for future additions to this sub-registry depends on 1402 the value of the SFID, as defined in Figure 29. These specifications 1403 must follow the guidelines of Section 5. 1405 +-----------+------------------------------+ 1406 | Range | Registration Procedures | 1407 +-----------+------------------------------+ 1408 | 0-128 | IETF Review or IESG Approval | 1409 | 128-255 | Expert Review | 1410 +-----------+------------------------------+ 1412 Figure 29: SF Identifier (SFID): Registration Procedures. 1414 8.2.6. 6P CellOptions bitmap 1416 The name of the sub-registry is "6P CellOptions bitmap". 1418 A Note included in this registry should say: "In the 6top Protocol 1419 (6P) version 0 [RFCXXXX], there is an optional CellOptions field 1420 which is 8 bits in size." 1422 Each entry in the sub-registry must include the bit position in the 1423 range 0-7, the corresponding Name, and a reference to the bit's 1424 documentation. 1426 Initial entries in this sub-registry are as follows: 1428 +-----+---------------+-----------+ 1429 | bit | Name | Reference | 1430 +-----+---------------+-----------+ 1431 | 0 | TX (Transmit) | RFCXXXX | 1432 | 1 | RX (Receive) | RFCXXXX | 1433 | 2 | SHARED | RFCXXXX | 1434 | 3-7 | Reserved | | 1435 +-----+---------------+-----------+ 1437 Figure 30: 6P CellOptions bitmap. 1439 All other Message Types are Reserved. 1441 The IANA policy for future additions to this sub-registry is "IETF 1442 Review or IESG Approval" as described in [RFC5226]. 1444 9. References 1445 9.1. Normative References 1447 [I-D.kivinen-802-15-ie] 1448 Kivinen, T. and P. Kinney, "IEEE 802.15.4 Information 1449 Element for IETF", draft-kivinen-802-15-ie-06 (work in 1450 progress), March 2017. 1452 [IEEE802154-2015] 1453 IEEE standard for Information Technology, "IEEE Std 1454 802.15.4-2015 - IEEE Standard for Low-Rate Wireless 1455 Personal Area Networks (WPANs)", October 2015. 1457 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1458 Requirement Levels", BCP 14, RFC 2119, 1459 DOI 10.17487/RFC2119, March 1997, 1460 . 1462 9.2. Informative References 1464 [I-D.ietf-6tisch-minimal] 1465 Vilajosana, X., Pister, K., and T. Watteyne, "Minimal 1466 6TiSCH Configuration", draft-ietf-6tisch-minimal-21 (work 1467 in progress), February 2017. 1469 [OpenWSN] Watteyne, T., Vilajosana, X., Kerkez, B., Chraim, F., 1470 Weekly, K., Wang, Q., Glaser, S., and K. Pister, "OpenWSN: 1471 a Standards-Based Low-Power Wireless Development 1472 Environment", Transactions on Emerging Telecommunications 1473 Technologies , August 2012. 1475 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 1476 IANA Considerations Section in RFCs", RFC 5226, 1477 DOI 10.17487/RFC5226, May 2008, 1478 . 1480 [RFC6982] Sheffer, Y. and A. Farrel, "Improving Awareness of Running 1481 Code: The Implementation Status Section", RFC 6982, 1482 DOI 10.17487/RFC6982, July 2013, 1483 . 1485 [RFC7554] Watteyne, T., Ed., Palattella, M., and L. Grieco, "Using 1486 IEEE 802.15.4e Time-Slotted Channel Hopping (TSCH) in the 1487 Internet of Things (IoT): Problem Statement", RFC 7554, 1488 DOI 10.17487/RFC7554, May 2015, 1489 . 1491 Appendix A. [TEMPORARY] Changelog 1493 o draft-ietf-6tisch-6top-protocol-05 1495 * complete reorder of sections. Merged protocol behavior and 1496 command description 1497 * STATUS to COUNT 1498 * written-out IANA section 1499 * complete proof-read 1500 o draft-ietf-6tisch-6top-protocol-04 1502 * recommendation on which cells to use for 6P traffic 1503 * relocation format: added numberofCells field 1504 * created separate section about "cell suggestion" 1505 * Added RC_ERR_CELLLIST and RC_ERR_EOL error codes 1506 * Added example for two step with the failure 1507 * Recommended numbers in IANA section 1508 * single generation number 1509 * IEEE802.15.4 -> IEEE Std 802.15.4 or 802.15.4 1510 * complete proof-read 1511 o draft-ietf-6tisch-6top-protocol-03 1513 * Added a reference to [I-D.kivinen-802-15-ie]. 1514 * Added the Type field. 1515 * Editorial changes (figs, typos, ...) 1516 o draft-ietf-6tisch-6top-protocol-02 1518 * Rename COUNT to STATUS 1519 * Split LIST to LIST AB and LIST BA 1520 * Added generation counters and describing generation tracking of 1521 the schedule 1522 * Editorial changes (figs, typos, ...) 1523 o draft-ietf-6tisch-6top-protocol-01 1525 * Clarifying locking of resources in concurrent transactions 1526 * Clarifying return of RC_ERR_BUSY in case of concurrent 1527 transactions without enough resources 1528 o draft-ietf-6tisch-6top-protocol-00 1530 * Informational to Std track 1531 o draft-wang-6tisch-6top-protocol-00 1533 * Editorial overhaul: fixing typos, increasing readability, 1534 clarifying figures. 1535 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1536 issues/47 1537 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1538 issues/54 1540 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1541 issues/55 1542 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1543 issues/49 1544 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1545 issues/53 1546 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1547 issues/44 1548 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1549 issues/48 1550 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1551 issues/43 1552 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1553 issues/52 1554 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1555 issues/45 1556 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1557 issues/51 1558 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1559 issues/50 1560 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1561 issues/46 1562 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1563 issues/41 1564 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1565 issues/42 1566 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1567 issues/39 1568 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1569 issues/40 1570 o draft-wang-6tisch-6top-sublayer-05 1572 * Specifies format of IE 1573 * Adds token in messages to match request and response 1574 o draft-wang-6tisch-6top-sublayer-04 1576 * Renames IANA_6TOP_IE_GROUP_ID to IANA_IETF_IE_GROUP_ID. 1577 * Renames IANA_CMD and IANA_RC to IANA_6TOP_CMD and IANA_6TOP_RC. 1578 * Proposes IANA_6TOP_SUBIE_ID with value 0x00 for the 6top sub- 1579 IE. 1580 o draft-wang-6tisch-6top-sublayer-03 1582 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top- 1583 protocol/issues/32/missing-command-list 1584 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top- 1585 protocol/issues/31/missing-command-count 1586 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top- 1587 protocol/issues/30/missing-command-clear 1589 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1590 issues/37/6top-atomic-transaction-6p-transaction 1591 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top- 1592 protocol/issues/35/separate-opcode-from-rc 1593 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top- 1594 protocol/issues/36/add-length-field-in-ie 1595 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top- 1596 protocol/issues/27/differentiate-rc_err_busy-and 1597 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top- 1598 protocol/issues/29/missing-rc-rc_reset 1599 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top- 1600 protocol/issues/28/the-sf-must-specify-the-behavior-of-a-mote 1601 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top- 1602 protocol/issues/26/remove-including-their-number 1603 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top-protocol/ 1604 issues/34/6of-sf 1605 * https://bitbucket.org/6tisch/draft-wang-6tisch-6top- 1606 protocol/issues/33/add-a-figure-showing-the-negociation 1607 o draft-wang-6tisch-6top-sublayer-02 1609 * introduces the 6P protocol and the notion of 6top Transaction. 1610 * introduces the concept of 6OF and its 6OFID. 1612 Authors' Addresses 1614 Qin Wang (editor) 1615 Univ. of Sci. and Tech. Beijing 1616 30 Xueyuan Road 1617 Beijing, Hebei 100083 1618 China 1620 Email: wangqin@ies.ustb.edu.cn 1622 Xavier Vilajosana 1623 Universitat Oberta de Catalunya 1624 156 Rambla Poblenou 1625 Barcelona, Catalonia 08018 1626 Spain 1628 Email: xvilajosana@uoc.edu 1629 Thomas Watteyne 1630 Analog Devices 1631 32990 Alvarado-Niles Road, Suite 910 1632 Union City, CA 94587 1633 USA 1635 Email: twatteyne@linear.com