idnits 2.17.1 draft-ietf-lpwan-schc-compound-ack-03.txt: -(6): Line appears to be too long, but this could be caused by non-ascii characters in UTF-8 encoding -(9): Line appears to be too long, but this could be caused by non-ascii characters in UTF-8 encoding Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- == There are 6 instances of lines with non-ascii characters in the document. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- ** The document seems to lack an IANA Considerations section. (See Section 2.2 of https://www.ietf.org/id-info/checklist for how to handle the case when there are no actions for IANA.) ** There are 7 instances of too long lines in the document, the longest one being 27 characters in excess of 72. ** The abstract seems to contain references ([RFC8376], [RFC8724]), which it shouldn't. Please replace those with straight textual mentions of the documents in question. ** The document seems to lack a both a reference to RFC 2119 and the recommended RFC 2119 boilerplate, even if it appears to use RFC 2119 keywords. RFC 2119 keyword, line 137: '...ound ACK message MUST be ordered from ...' RFC 2119 keyword, line 153: '...CHC Compound ACK MAY be used. The SCH...' RFC 2119 keyword, line 156: '...sent in the SCHC Compound ACK, MUST be...' RFC 2119 keyword, line 169: '...CHC Compound ACK MUST NOT use the Comp...' RFC 2119 keyword, line 171: '...mediate bitmaps fields MUST be of size...' (11 more instances...) Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (8 February 2022) is 801 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-21) exists of draft-ietf-lpwan-schc-yang-data-model-04 ** Downref: Normative reference to an Informational RFC: RFC 8376 Summary: 5 errors (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 lpwan Working Group JC. Zuniga 3 Internet-Draft SIGFOX 4 Intended status: Standards Track C. Gomez 5 Expires: 12 August 2022 S. Aguilar 6 Universitat Politècnica de Catalunya 7 L. Toutain 8 IMT-Atlantique 9 S. Céspedes 10 D. Wistuba 11 NIC Labs, Universidad de Chile 12 8 February 2022 14 SCHC Compound ACK 15 draft-ietf-lpwan-schc-compound-ack-03 17 Abstract 19 The present document describes an extension to the SCHC (Static 20 Context Header Compression and fragmentation) protocol [RFC8724]. It 21 defines a SCHC Compound ACK message format, which is intended to 22 reduce the number of response transmissions (i.e., SCHC ACKs) by 23 accumulating bitmaps of several windows in a single SCHC message 24 (i.e., the SCHC Compound ACK). 26 The message format is generic, and can be used, for instance, by any 27 of the four LWPAN technologies defined in [RFC8376], being Sigfox, 28 LoRaWAN, NB-IoT and IEEE 802.15.4w. 30 Status of This Memo 32 This Internet-Draft is submitted in full conformance with the 33 provisions of BCP 78 and BCP 79. 35 Internet-Drafts are working documents of the Internet Engineering 36 Task Force (IETF). Note that other groups may also distribute 37 working documents as Internet-Drafts. The list of current Internet- 38 Drafts is at https://datatracker.ietf.org/drafts/current/. 40 Internet-Drafts are draft documents valid for a maximum of six months 41 and may be updated, replaced, or obsoleted by other documents at any 42 time. It is inappropriate to use Internet-Drafts as reference 43 material or to cite them other than as "work in progress." 45 This Internet-Draft will expire on 12 August 2022. 47 Copyright Notice 49 Copyright (c) 2022 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 54 license-info) in effect on the date of publication of this document. 55 Please review these documents carefully, as they describe your rights 56 and restrictions with respect to this document. Code Components 57 extracted from this document must include Revised BSD License text as 58 described in Section 4.e of the Trust Legal Provisions and are 59 provided without warranty as described in the Revised BSD License. 61 Table of Contents 63 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 64 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 65 3. SCHC Compound ACK . . . . . . . . . . . . . . . . . . . . . . 3 66 3.1. SCHC Compound ACK Message Format . . . . . . . . . . . . 4 67 3.2. SCHC Compound ACK Behaviour . . . . . . . . . . . . . . . 5 68 3.2.1. Sender Behaviour . . . . . . . . . . . . . . . . . . 5 69 3.2.2. Receiver Behaviour . . . . . . . . . . . . . . . . . 6 70 3.3. SCHC Compound ACK Examples . . . . . . . . . . . . . . . 6 71 3.4. SCHC Compound ACK YANG Data Model . . . . . . . . . . . . 7 72 3.4.1. SCHC YANG Data Model Extension . . . . . . . . . . . 7 73 3.4.2. SCHC YANG Tree Extension . . . . . . . . . . . . . . 10 74 4. SCHC Compound ACK Parameters . . . . . . . . . . . . . . . . 10 75 5. Security considerations . . . . . . . . . . . . . . . . . . . 10 76 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10 77 7. Normative References . . . . . . . . . . . . . . . . . . . . 11 78 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 80 1. Introduction 82 The Generic Framework for Static Context Header Compression and 83 Fragmentation (SCHC) specification [RFC8724] describes two 84 mechanisms: i) a protocol header compression scheme, and ii) a frame 85 fragmentation and loss recovery functionality. Either can be used on 86 top of radio technologies such as the four LWPAN defined in 87 [RFC8376], being Sigfox, LoRaWAN, NB-IoT and IEEE 802.15.4w. These 88 LPWANs have similar characteristics such as star-oriented topologies, 89 network architecture, connected devices with built-in applications, 90 etc. 92 SCHC offers a great level of flexibility to accommodate all these 93 LPWAN technologies. Even though there are a great number of 94 similarities between them, some differences exist with respect to the 95 transmission characteristics, payload sizes, etc. Hence, there are 96 optimal parameters and modes of operation that can be used when SCHC 97 is used on top of a specific LPWAN technology. 99 The present document describes an extension to the SCHC protocol for 100 frame fragmentation and loss recovery. It defines a SCHC Compound 101 ACK format, which is intended to reduce the number of response 102 transmissions (i.e., SCHC ACKs) in the ACK-on-Error mode of SCHC. 103 The SCHC Compound ACK extends the SCHC ACK message format so that it 104 can contain several bitmaps, each bitmap being identified by its 105 corresponding window number. 107 The SCHC Compound ACK: 109 * provides feedback only for windows with fragment losses, 111 * has a variable size that depends on the number of windows with 112 fragment losses being reported in the single Compound SCHC ACK, 114 * includes the window number (i.e., W) of each bitmap, 116 * has the same SCHC ACK format defined in [RFC8724] when only one 117 window with losses is reported, 119 * might not cover all windows with fragment losses of a SCHC Packet, 121 * and is distinguishable from the SCHC Receiver-Abort. 123 2. Terminology 125 It is assumed that the reader is familiar with the terms and 126 mechanisms defined in [RFC8376] and in [RFC8724]. 128 3. SCHC Compound ACK 130 The SCHC Compound ACK is a SCHC ACK message that can contain several 131 bitmaps, each bitmap being identified by its corresponding window 132 number. 134 The SCHC Compound ACK groups the window number (W) with its 135 corresponding bitmap. Windows do not need to be contiguous. 136 However, the window numbers and corresponding bitmaps included in the 137 SCHC Compound ACK message MUST be ordered from the lowest-numbered to 138 the highest-numbered window. 140 3.1. SCHC Compound ACK Message Format 142 Figure 1 shows the regular SCHC ACK format when all fragments have 143 been correctly received (C=1), as defined in [RFC8724]. 145 |- SCHC ACK Header --| 146 + -------+---+------ + ------------ + 147 | RuleID | W | C=b'1 | b'0-pad(opt) | 148 + ------ + - + ----- + ------------ + 150 Figure 1: SCHC Success ACK message format, as defined in RFC8724 152 In case SCHC Fragment losses are found in any of the windows of the 153 SCHC Packet, the SCHC Compound ACK MAY be used. The SCHC Compound 154 ACK message format is shown in Figure 2. 156 The window numbered 00, if present in the SCHC Compound ACK, MUST be 157 placed between the Rule ID and the C bit to avoid confusion with 158 padding bits. 160 |--SCHC ACK Header--| W = w1 |...| W = wi | 161 +-------------------+ ------ +...+ ------- + ------ +------------+ 162 |RuleID|W=b'w1|C=b'0| Bitmap |...| W=b'wi | Bitmap |b'0-pad(opt)| 163 +------+------+-----+ ------ +...+ ------- + ------ +------------+ 165 Losses are found in windows W = w1,...,wi; where w1| 263 |-----W=0, FCN=5 ----->| 264 |-----W=0, FCN=4 ----->| 265 |-----W=0, FCN=3 ----->| 266 |-----W=0, FCN=2 --X-->| 267 |-----W=0, FCN=1 ----->| 268 |-----W=0, FCN=0 ----->| Bitmap: 1111011 269 (no ACK) 270 |-----W=1, FCN=6 ----->| 271 |-----W=1, FCN=5 ----->| 272 |-----W=1, FCN=4 ----->| 273 |-----W=1, FCN=3 ----->| 274 |-----W=1, FCN=2 ----->| 275 |-----W=1, FCN=1 --X-->| 276 |-- W=1, FCN=7 + RCS ->| Integrity check: failure 277 |<--- Compound ACK ----| [C=0, W=0 - Bitmap:1111011, 278 |-----W=0, FCN=2 ----->| W=1 - Bitmap:1111101] 279 |-----W=1, FCN=1 ----->| Integrity check: success 280 |<--- ACK, W=1, C=1 ---| C=1 281 (End) 283 Figure 3: SCHC Compound ACK message sequence example 285 |-- SCHC ACK Header ---|- W=00 --|----- W=01 -----| 286 + -------------------- + ------- + ---- + ------- + ------------- + 287 | RuleID | W=00 | C=0 | 1111011 | W=01 | 1111101 | b'0-pad (opt) | 288 + ------ + ------ + -- + ------- + ---- + ------- + ------------- + 290 Figure 4: SCHC Compound ACK message format example: Losses are 291 found in windows 00 and 01 293 3.4. SCHC Compound ACK YANG Data Model 295 The present document also extends the SCHC YANG data model defined in 296 [I-D.ietf-lpwan-schc-yang-data-model] by including a new leaf in the 297 Ack-on-Error fragmentation mode to describe both the option to use 298 the SCHC Compound ACK, as well as its bitmap format. 300 3.4.1. SCHC YANG Data Model Extension 301 file "ietf-compound-ack@2021-12-10.yang" 302 module ietf-schc-compound-ack { 303 yang-version 1.1; 304 namespace "urn:ietf:params:xml:ns:yang:ietf-schc-compound-ack"; 305 prefix schc-compound-ack; 307 import ietf-schc { 308 prefix schc; 309 } 311 organization 312 "IETF IPv6 over Low Power Wide-Area Networks (lpwan) working group"; 313 contact 314 "WG Web: 315 WG List: 316 Editor: Laurent Toutain 317 318 Editor: Juan Carlos Zuniga 319 "; 320 description 321 " 322 Copyright (c) 2021 IETF Trust and the persons identified as 323 authors of the code. All rights reserved. 324 Redistribution and use in source and binary forms, with or 325 without modification, is permitted pursuant to, and subject to 326 the license terms contained in, the Simplified BSD License set 327 forth in Section 4.c of the IETF Trust's Legal Provisions 328 Relating to IETF Documents 329 (https://trustee.ietf.org/license-info). 330 This version of this YANG module is part of RFC XXXX 331 (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself 332 for full legal notices. 333 The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL 334 NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED', 335 'MAY', and 'OPTIONAL' in this document are to be interpreted as 336 described in BCP 14 (RFC 2119) (RFC 8174) when, and only when, 337 they appear in all capitals, as shown here. 339 *************************************************************** 341 This module extends the ietf-schc module to include the 342 Compound ACK behavior for ACK-on-Error as defined in RFC YYYY. 343 It introduces a new leaf for ACK-on-Error defining the format 344 of the SCHC Compound ACK, adding the possibility to send 345 several bitmaps in a single SCHC ACK message."; 347 revision 2022-02-08 { 348 description 349 "Initial version for RFC YYYY "; 350 reference 351 "RFC YYYY: SCHC Compound ACK"; 352 } 354 identity bitmap-format-base-type { 355 description 356 "Define how the bitmap is formed in ACK messages."; 357 } 359 identity bitmap-RFC8724 { 360 base bitmap-format-base-type; 361 description 362 "Bitmap by default as defined in RFC8724."; 363 } 365 identity bitmap-compound-ack { 366 base bitmap-format-base-type; 367 description 368 "Compound ACK."; 369 } 371 typedef bitmap-format-type { 372 type identityref { 373 base bitmap-format-base-type; 374 } 375 description 376 "type used in rules"; 377 } 379 augment "/schc:schc/schc:rule/schc:nature/schc:fragmentation/schc:mode/schc:ack-on-error" { 380 leaf bitmap-format { 381 when "derived-from(../schc:fragmentation-mode, 'schc:fragmentation-mode-ack-on-error')"; 382 type schc-compound-ack:bitmap-format-type; 383 default "schc-compound-ack:bitmap-RFC8724"; 384 description 385 "How the bitmaps are included in the SCHC ACK message."; 386 } 388 leaf last-bitmap-compression { 389 when "derived-from(../schc:fragmentation-mode, 'schc:fragmentation-mode-ack-on-error')"; 390 type boolean; 391 default true; 392 description 393 "when true ultimate bitmap in the SCHC ACK message can be compressed"; 394 } 396 description 397 "added to SCHC rules"; 398 } 400 } 401 403 Figure 5: SCHC YANG Data Model - Compound ACK extension 405 3.4.2. SCHC YANG Tree Extension 407 augment /schc:schc/schc:rule/schc:nature/schc:fragmentation/schc:mode/schc:ack-on-error: 408 +--rw bitmap-format? schc-compound-ack:bitmap-format-type 410 Figure 6: SCHC YANG Tree - Compound ACK extension 412 4. SCHC Compound ACK Parameters 414 This section lists the parameters related to the SCHC Compound ACK 415 usage that need to be defined in the Profile, in addition to the ones 416 listed in Annex D of [RFC8724]. 418 * Usage or not of the SCHC Compound ACK message. 420 * Usage or not of the compressed bitmap format in the last window of 421 the SCHC Compound ACK message. 423 * Differentiation between SCHC Receiver-Abort and SCHC Compound ACK 424 message, e.g., Receiver-Abort message padded with 1s with an extra 425 byte appended at the end, while the SCHC Compound ACK is 0-padded. 427 5. Security considerations 429 The current document specifies a message format extension for SCHC. 430 Hence, the same Security Considerations defined in [RFC8724] apply. 432 6. Acknowledgements 434 Carles Gomez has been funded in part by the Spanish Government 435 through the TEC2016-79988-P grant, and the PID2019-106808RA-I00 grant 436 (funded by MCIN / AEI / 10.13039/501100011033), and by Secretaria 437 d'Universitats i Recerca del Departament d'Empresa i Coneixement de 438 la Generalitat de Catalunya 2017 through grant SGR 376. 440 Sergio Aguilar has been funded by the ERDF and the Spanish Government 441 through project TEC2016-79988-P and project PID2019-106808RA-I00, 442 AEI/FEDER, EU (funded by MCIN / AEI / 10.13039/501100011033). 444 Sandra Cespedes has been funded in part by the ANID Chile Project 445 FONDECYT Regular 1201893 and Basal Project FB0008. 447 Diego Wistuba has been funded by the ANID Chile Project FONDECYT 448 Regular 1201893. 450 The authors would like to thank Rafael Vidal, Julien Boite, Renaud 451 Marty, Antonis Platis, Dominique Barthel and Pascal Thubert for their 452 very useful comments, reviews and implementation design 453 considerations. 455 7. Normative References 457 [I-D.ietf-lpwan-schc-yang-data-model] 458 Minaburo, A. and L. Toutain, "Data Model for Static 459 Context Header Compression (SCHC)", Work in Progress, 460 Internet-Draft, draft-ietf-lpwan-schc-yang-data-model-04, 461 February 2021, . 464 [RFC8376] Farrell, S., Ed., "Low-Power Wide Area Network (LPWAN) 465 Overview", RFC 8376, DOI 10.17487/RFC8376, May 2018, 466 . 468 [RFC8724] Minaburo, A., Toutain, L., Gomez, C., Barthel, D., and JC. 469 Zuniga, "SCHC: Generic Framework for Static Context Header 470 Compression and Fragmentation", RFC 8724, 471 DOI 10.17487/RFC8724, April 2020, 472 . 474 Authors' Addresses 476 Juan Carlos Zúñiga 477 SIGFOX 478 Montreal QC 479 Canada 481 Email: j.c.zuniga@ieee.org 483 Carles Gomez 484 Universitat Politècnica de Catalunya 485 C/Esteve Terradas, 7 486 08860 Castelldefels 487 Spain 489 Email: carlesgo@entel.upc.edu 490 Sergio Aguilar 491 Universitat Politècnica de Catalunya 492 C/Esteve Terradas, 7 493 08860 Castelldefels 494 Spain 496 Email: sergio.aguilar.romero@upc.edu 498 Laurent Toutain 499 IMT-Atlantique 500 2 rue de la Chataigneraie 501 CS 17607 502 35576 Cesson-Sevigne Cedex 503 France 505 Email: Laurent.Toutain@imt-atlantique.fr 507 Sandra Céspedes 508 NIC Labs, Universidad de Chile 509 Av. Almte. Blanco Encalada 1975 510 Santiago 511 Chile 513 Email: scespedes@niclabs.cl 515 Diego Wistuba 516 NIC Labs, Universidad de Chile 517 Av. Almte. Blanco Encalada 1975 518 Santiago 519 Chile 521 Email: wistuba@niclabs.cl