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Checking references for intended status: Informational ---------------------------------------------------------------------------- == Outdated reference: A later version (-22) exists of draft-ietf-6lo-nfc-17 == Outdated reference: A later version (-11) exists of draft-ietf-6lo-plc-09 Summary: 1 error (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 6Lo Working Group Y-G. Hong 3 Internet-Draft Daejeon University 4 Intended status: Informational C.G. Gomez 5 Expires: 29 July 2022 UPC 6 Y-H. Choi 7 ETRI 8 AR. Sangi 9 Huaiyin Institute of Technology 10 S. Chakrabarti 11 January 2022 13 IPv6 over Constrained Node Networks (6lo) Applicability & Use cases 14 draft-ietf-6lo-use-cases-12 16 Abstract 18 This document describes the applicability of IPv6 over constrained 19 node networks (6lo) and provides practical deployment examples. In 20 addition to IEEE Std 802.15.4, various link layer technologies such 21 as ITU-T G.9959 (Z-Wave), Bluetooth Low Energy, DECT-ULE, MS/TP, NFC, 22 and PLC are used as examples. The document targets an audience who 23 would like to understand and evaluate running end-to-end IPv6 over 24 the constrained node networks for local or Internet connectivity. 26 Status of This Memo 28 This Internet-Draft is submitted in full conformance with the 29 provisions of BCP 78 and BCP 79. 31 Internet-Drafts are working documents of the Internet Engineering 32 Task Force (IETF). Note that other groups may also distribute 33 working documents as Internet-Drafts. The list of current Internet- 34 Drafts is at https://datatracker.ietf.org/drafts/current/. 36 Internet-Drafts are draft documents valid for a maximum of six months 37 and may be updated, replaced, or obsoleted by other documents at any 38 time. It is inappropriate to use Internet-Drafts as reference 39 material or to cite them other than as "work in progress." 41 This Internet-Draft will expire on 5 July 2022. 43 Copyright Notice 45 Copyright (c) 2022 IETF Trust and the persons identified as the 46 document authors. All rights reserved. 48 This document is subject to BCP 78 and the IETF Trust's Legal 49 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 50 license-info) in effect on the date of publication of this document. 51 Please review these documents carefully, as they describe your rights 52 and restrictions with respect to this document. Code Components 53 extracted from this document must include Revised BSD License text as 54 described in Section 4.e of the Trust Legal Provisions and are 55 provided without warranty as described in the Revised BSD License. 57 Table of Contents 59 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 60 2. 6lo Link layer technologies . . . . . . . . . . . . . . . . . 4 61 2.1. ITU-T G.9959 . . . . . . . . . . . . . . . . . . . . . . 4 62 2.2. Bluetooth LE . . . . . . . . . . . . . . . . . . . . . . 4 63 2.3. DECT-ULE . . . . . . . . . . . . . . . . . . . . . . . . 5 64 2.4. MS/TP . . . . . . . . . . . . . . . . . . . . . . . . . . 5 65 2.5. NFC . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 66 2.6. PLC . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 67 2.7. Comparison between 6lo link layer technologies . . . . . 8 68 3. Guidelines for adopting IPv6 stack (6lo) . . . . . . . . . . 9 69 4. 6lo Deployment Scenarios . . . . . . . . . . . . . . . . . . 11 70 4.1. Wi-SUN usage of 6lo in network layer . . . . . . . . . . 11 71 4.2. Thread usage of 6lo in network layer . . . . . . . . . . 13 72 4.3. G3-PLC usage of 6lo in network layer . . . . . . . . . . 13 73 4.4. Netricity usage of 6lo in network layer . . . . . . . . . 14 74 5. 6lo Use Case Examples . . . . . . . . . . . . . . . . . . . . 15 75 5.1. Use case of ITU-T G.9959: Smart Home . . . . . . . . . . 15 76 5.2. Use case of Bluetooth LE: Smartphone-based Interaction . 16 77 5.3. Use case of DECT-ULE: Smart Home . . . . . . . . . . . . 17 78 5.4. Use case of MS/TP: Building Automation Networks . . . . . 17 79 5.5. Use case of NFC: Alternative Secure Transfer . . . . . . 18 80 5.6. Use case of PLC: Smart Grid . . . . . . . . . . . . . . . 19 81 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 82 7. Security Considerations . . . . . . . . . . . . . . . . . . . 20 83 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 20 84 9. Informative References . . . . . . . . . . . . . . . . . . . 20 85 Appendix A. Design Space Dimensions for 6lo Deployment . . . . . 26 86 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 28 88 1. Introduction 90 Running IPv6 on constrained node networks presents challenges, due to 91 the characteristics of these networks such as small packet size, low 92 power, low bandwidth, low cost, and large number of devices, among 93 others [RFC4919][RFC7228]. For example, many IEEE Std 802.15.4 94 variants [IEEE802154] exhibit a frame size of 127 octets, whereas 95 IPv6 requires its underlying layer to support an MTU of 1280 bytes. 97 Furthermore, those IEEE Std 802.15.4 variants do not offer 98 fragmentation and reassembly functionality. (It is noted that IEEE 99 Std 802.15.9-2016 provides multiplexing and fragmentation layer for 100 the IEEE Std 802.15.4[IEEE802159].) Therefore, an appropriate 101 adaptation layer supporting fragmentation and reassembly must be 102 provided below IPv6. Also, the limited IEEE Std 802.15.4 frame size 103 and low energy consumption requirements motivate the need for packet 104 header compression. The IETF IPv6 over Low-Power WPAN (6LoWPAN) 105 working group published a suite of specification that provide an 106 adaptation layer to support IPv6 over IEEE Std 802.15.4 comprising 107 the following functionality: 109 * Fragmentation and reassembly, address autoconfiguration, and a 110 frame format [RFC4944], 112 * IPv6 (and UDP) header compression [RFC6282], 114 * Neighbor Discovery Optimization for 6LoWPAN [RFC6775][RFC8505]. 116 As Internet of Things (IoT) services become more popular, the IETF 117 6lo working group [IETF_6lo] has defined adaptation layer 118 functionality to support IPv6 over various link layer technologies 119 other than IEEE Std 802.15.4, such as Bluetooth Low Energy (Bluetooth 120 LE), ITU-T G.9959 (Z-Wave), Digital Enhanced Cordless 121 Telecommunications - Ultra Low Energy (DECT-ULE), Master-Slave/Token 122 Passing (MS/TP), Near Field Communication (NFC), and Power Line 123 Communication (PLC). The 6lo adaptation layers use a variation of 124 the 6LoWPAN stack applied to each particular link layer technology. 126 The 6LoWPAN working group produced the document entitled "Design and 127 Application Spaces for 6LoWPANs" [RFC6568], which describes potential 128 application scenarios and use cases for low-power wireless personal 129 area networks. The present document aims to provide guidance to an 130 audience who are new to the IPv6 over constrained node networks (6lo) 131 concept and want to assess its application to the constrained node 132 network of their interest. This 6lo applicability document describes 133 a few sets of practical 6lo deployment scenarios and use cases 134 examples. In addition, it considers various network design space 135 dimensions such as deployment, network size, power source, 136 connectivity, multi-hop communication, traffic pattern, security 137 level, mobility, and QoS requirements etc. 139 This document provides the applicability and use cases of 6lo, 140 considering the following aspects: 142 * It covers various IoT-related wired/wireless link layer 143 technologies providing practical information of such technologies. 145 * It provides a general guideline on how the 6LoWPAN stack can be 146 modified for a given L2 technology. 148 * Various 6lo use cases and practical deployment examples are 149 described. 151 2. 6lo Link layer technologies 153 2.1. ITU-T G.9959 155 The ITU-T G.9959 Recommendation [G.9959] targets low-power Wireless 156 Personal Area Networks (WPANs), and defines physical layer and link 157 layer functionality. Physical layers of 9.6 kbit/s, 40 kbit/s and 158 100 kbit/s are supported. G.9959 defines how a unique 32-bit HomeID 159 network identifier is assigned by a network controller and how an 160 8-bit NodeID host identifier is allocated to each node. NodeIDs are 161 unique within the network identified by the HomeID. The G.9959 162 HomeID represents an IPv6 subnet that is identified by one or more 163 IPv6 prefixes [RFC7428]. The ITU-T G.9959 can be used for smart home 164 applications. 166 2.2. Bluetooth LE 168 Bluetooth LE was introduced in Bluetooth 4.0, enhanced in Bluetooth 169 4.1, and developed further in successive versions. Bluetooth SIG has 170 also published the Internet Protocol Support Profile (IPSP). The 171 IPSP enables discovery of IP-enabled devices and establishment of 172 link-layer connection for transporting IPv6 packets. IPv6 over 173 Bluetooth LE is dependent on both Bluetooth 4.1 and IPSP 1.0 or 174 newer. 176 Many devices such as mobile phones, notebooks, tablets and other 177 handheld computing devices which support Bluetooth 4.0 or subsequent 178 versions also support the low-energy variant of Bluetooth. Bluetooth 179 LE is also being included in many different types of accessories that 180 collaborate with mobile devices. An example of a use case for a 181 Bluetooth LE accessory is a heart rate monitor that sends data via 182 the mobile phone to a server on the Internet [RFC7668]. A typical 183 usage of Bluetooth LE is smartphone-based interaction with 184 constrained devices. Bluetooth LE was originally designed to enable 185 star topology networks. However, recent Bluetooth versions support 186 the formation of extended topologies, and IPv6 support for mesh 187 networks of Bluetooth LE devices is being developed [RFC9159]. 189 2.3. DECT-ULE 191 DECT-ULE is a low power air interface technology that is designed to 192 support both circuit switched services, such as voice communication, 193 and packet mode data services at modest data rate. 195 The DECT-ULE protocol stack consists of the physical layer operating 196 at frequencies in the dedicated 1880 - 1920 MHz frequency band 197 depending on the region and uses a symbol rate of 1.152 Mbps. Radio 198 bearers are allocated by use of FDMA/TDMA/TDD techniques. 200 In its generic network topology, DECT is defined as a cellular 201 network technology. However, the most common configuration is a star 202 network with a single Fixed Part (FP) defining the network with a 203 number of Portable Parts (PP) attached. The Medium Access Control 204 (MAC) layer supports traditional DECT as this is used for services 205 like discovery, pairing, security features etc. All these features 206 have been reused from DECT. 208 The DECT-ULE device can switch to the ULE mode of operation, 209 utilizing the new ULE MAC layer features. The DECT-ULE Data Link 210 Control (DLC) provides multiplexing as well as segmentation and re- 211 assembly for larger packets from layers above. The DECT-ULE layer 212 also implements per-message authentication and encryption. The DLC 213 layer ensures packet integrity and preserves packet order, but 214 delivery is based on best effort. 216 The current DECT-ULE MAC layer standard supports low bandwidth data 217 broadcast. However the usage of this broadcast service has not yet 218 been standardized for higher layers [RFC8105]. DECT-ULE can be used 219 for smart metering in a home. 221 2.4. MS/TP 223 MS/TP is a MAC protocol for the RS-485 [TIA-485-A] physical layer and 224 is used primarily in building automation networks. 226 An MS/TP device is typically based on a low-cost microcontroller with 227 limited processing power and memory. These constraints, together 228 with low data rates and a small MAC address space, are similar to 229 those faced in 6LoWPAN networks. MS/TP differs significantly from 230 6LoWPAN in at least three respects: a) MS/TP devices are typically 231 mains powered, b) all MS/TP devices on a segment can communicate 232 directly so there are no hidden node or mesh routing issues, and c) 233 the latest MS/TP specification provides support for large payloads, 234 eliminating the need for fragmentation and reassembly below IPv6. 236 MS/TP is designed to enable multidrop networks over shielded twisted 237 pair wiring. It can support network segments up to 1000 meters in 238 length at a data rate of 115.2 kbit/s or segments up to 1200 meters 239 in length at lower bit rates. An MS/TP interface requires only a 240 Universal Asynchronous Receiver-Transmitter (UART), an RS-485 241 [TIA-485-A] transceiver with a driver that can be disabled, and a 5 242 ms resolution timer. The MS/TP MAC is typically implemented in 243 software. 245 Because of its superior "range" (~1 km) compared to many low power 246 wireless data links, MS/TP may be suitable to connect remote devices 247 (such as district heating controllers) to the nearest building 248 control infrastructure over a single link [RFC8163]. 250 2.5. NFC 252 NFC technology enables simple and safe two-way interactions between 253 electronic devices, allowing consumers to perform contactless 254 transactions, access digital content, and connect electronic devices 255 with a single touch. NFC complements many popular consumer level 256 wireless technologies, by utilizing the key elements in existing 257 standards for contactless card technology (ISO/IEC 14443 A&B and 258 JIS-X 6319-4). 260 Extending the capability of contactless card technology, NFC also 261 enables devices to share information at a distance that is less than 262 10 cm with a maximum communication speed of 424 kbps. Users can 263 share business cards, make transactions, access information from a 264 smart poster or provide credentials for access control systems with a 265 simple touch. 267 NFC's bidirectional communication ability is ideal for establishing 268 connections with other technologies by the simplicity of touch. In 269 addition to the easy connection and quick transactions, simple data 270 sharing is also available [I-D.ietf-6lo-nfc]. NFC can be used for 271 secure transfer in healthcare services. 273 2.6. PLC 275 PLC is a data transmission technique that utilizes power conductors 276 as medium [I-D.ietf-6lo-plc]. Unlike other dedicated communication 277 infrastructure, power conductors are widely available indoors and 278 outdoors. Moreover, wired technologies cause less interference to 279 the radio medium than wireless technologies and are more reliable 280 than their wireless counterparts. 282 The below table shows some available open standards defining PLC. 284 +=============+=================+============+===========+==========+ 285 | PLC Systems | Frequency Range | Type | Data | Distance | 286 | | | | Rate | | 287 +=============+=================+============+===========+==========+ 288 | IEEE1901 | <100MHz | Broadband | 200Mbps | 1000m | 289 +-------------+-----------------+------------+-----------+----------+ 290 | IEEE1901.1 | <12MHz | PLC-IoT | 10Mbps | 2000m | 291 +-------------+-----------------+------------+-----------+----------+ 292 | IEEE1901.2 | <500kHz | Narrowband | 200kbps | 3000m | 293 +-------------+-----------------+------------+-----------+----------+ 294 | G3-PLC | <500kHz | Narrowband | 234kbps | 3000m | 295 +-------------+-----------------+------------+-----------+----------+ 297 Table 1: Some Available Open Standards in PLC 299 IEEE Std 1901 [IEEE1901] defines a broadband variant of PLC but is 300 effective within short range. This standard addresses the 301 requirements of applications with high data rate such as: Internet, 302 HDTV, Audio, Gaming etc. Broadband operates on Orthogonal Frequency 303 Division Multiplexing (OFDM) modulation. 305 IEEE Std 1901.1 [IEEE1901.1] defines a medium frequency band (less 306 than 12 MHz) broadband PLC technology for smart grid applications 307 based on OFDM. By achieving an extended communication range with 308 medium speeds, this standard can be applied both in indoor and 309 outdoor scenarios, such as Advanced Metering Infrastructure (AMI), 310 street lighting, electric vehicle charging, smart city etc. 312 IEEE Std 1901.2 [IEEE1901.2] defines a narrowband variant of PLC with 313 less data rate but significantly higher transmission range that could 314 be used in an indoor or even an outdoor environment. It is 315 applicable to typical IoT applications such as: Building Automation, 316 Renewable Energy, Advanced Metering, Street Lighting, Electric 317 Vehicle, Smart Grid etc. Moreover, IEEE Std 1901.2 standard is based 318 on the 802.15.4 MAC sub-layer and fully endorses the security scheme 319 defined in 802.15.4 [RFC8036]. A typical use case of PLC is smart 320 grid. 322 G3-PLC [G3-PLC] is a narrowband PLC technology that is based on the 323 ITU-T G.9903 Recommendation [G.9903]. The ITU-T G.9903 324 Recommendation contains the physical layer and data link layer 325 specification for the G3-PLC narrowband OFDM power line communication 326 transceivers, for communications via alternating current and direct 327 current electric power lines over frequencies below 500 kHz. 329 2.7. Comparison between 6lo link layer technologies 331 In above clauses, various 6lo link layer technologies are described. 332 The following table shows dominant parameters of each use case 333 corresponding to the 6lo link layer technology. 335 +--------------+---------+---------+---------+---------+---------+---------+ 336 | | Z-Wave | BLE | DECT-ULE| MS/TP | NFC | PLC | 337 +--------------+---------+---------+---------+---------+---------+---------+ 338 | | Home | Interact| | Building| Health- | | 339 | Usage | Auto- | w/ Smart| Meter | Auto- | care | Smart | 340 | | mation | Phone | Reading | mation | Service | Grid | 341 +--------------+---------+---------+---------+---------+---------+---------+ 342 | Topology | L2-mesh | Star | Star | MS/TP | P2P | Star | 343 | & | or | & | | | | Tree | 344 | Subnet | L3-mesh | Mesh | No mesh | No mesh | L2-mesh | Mesh | 345 +--------------+---------+---------+---------+---------+---------+---------+ 346 | | | | | | | | 347 | Mobility | No | Low | No | No | Moderate| No | 348 | Requirement | | | | | | | 349 +--------------+---------+---------+---------+---------+---------+---------+ 350 | | High + | | High + | High + | | High + | 351 | Security | Privacy |Partially| Privacy | Authen. | High | Encrypt.| 352 | Requirement | required| | required| required| | required| 353 +--------------+---------+---------+---------+---------+---------+---------+ 354 | | | | | | | | 355 | Buffering | Low | Low | Low | Low | Low | Low | 356 | Requirement | | | | | | | 357 +--------------+---------+---------+---------+---------+---------+---------+ 358 | Latency, | | | | | | | 359 | QoS | High | Low | Low | High | High | Low | 360 | Requirement | | | | | | | 361 +--------------+---------+---------+---------+---------+---------+---------+ 362 | | | | | | | | 363 | Data | Infrequ-| Infrequ-| Infrequ-| Frequent| Small | Infrequ-| 364 | Rate | ent | ent | ent | | | ent | 365 +--------------+---------+---------+---------+---------+---------+---------+ 366 | RFC # | | | | | draft- | draft- | 367 | or | RFC7428 | RFC7668,| RFC8105 | RFC8163 | ietf-6lo| ietf-6lo| 368 | Draft | | RFC9159 | | | -nfc | -plc | 369 +--------------+---------+---------+---------+---------+---------+---------+ 371 Table 2: Comparison between 6lo link layer technologies 373 3. Guidelines for adopting IPv6 stack (6lo) 375 6lo aims at reusing and/or adapting existing 6LoWPAN functionality in 376 order to efficiently support IPv6 over a variety of IoT L2 377 technologies. The following guideline targets new candidate 378 constrained L2 technologies that may be considered for running a 379 modified 6LoWPAN stack on top. The modification of 6LoWPAN stack 380 should be based on the following: 382 * Addressing Model: Addressing model determines whether the device 383 is capable of forming IPv6 link-local and global addresses and 384 what is the best way to derive the IPv6 addresses for the 385 constrained L2 devices. L2-address-derived IPv6 addresses are 386 specified in [RFC4944], but there exist implications for privacy. 387 For global usage, a unique IPv6 address must be derived using an 388 assigned prefix and a unique interface ID. [RFC8065] provides 389 such guidelines. For MAC-derived IPv6 addresses, please refer to 390 [RFC8163] for IPv6 address mapping examples. Broadcast and 391 multicast support are dependent on the L2 networks. Most low- 392 power L2 implementations map multicast to broadcast networks. So 393 care must be taken in the design when to use broadcast and try to 394 stick to unicast messaging whenever possible. 396 * MTU Considerations: The deployment should consider packet maximum 397 transmission unit (MTU) needs over the link layer and should 398 consider if fragmentation and reassembly of packets are needed at 399 the 6LoWPAN layer. For example, if the link layer supports 400 fragmentation and reassembly of packets, then the 6LoWPAN layer 401 may not need to support fragmentation/reassembly. In fact, for 402 most efficiency, choosing a low-power link layer that can carry 403 unfragmented application packets would be optimum for packet 404 transmission if the deployment can afford it. Please refer to 6lo 405 RFCs [RFC7668], [RFC8163], [RFC8105] for example guidance. 407 * Mesh or L3-Routing: 6LoWPAN specifications provide mechanisms to 408 support mesh routing at L2, a configuration called mesh-under 409 [RFC6606]. It is also possible to use an L3 routing protocol in 410 6LoWPAN, an approach known as route-over. [RFC6550] defines RPL, 411 a L3 routing protocol for low power and lossy networks using 412 directed acyclic graphs. 6LoWPAN is routing-protocol-agnostic and 413 does not specify any particular L2 or L3 routing protocol to use 414 with a 6LoWPAN stack. 416 * Address Assignment: 6LoWPAN developed a new version of IPv6 417 Neighbor Discovery [RFC4861][RFC4862]. 6LoWPAN Neighbor Discovery 418 [RFC6775][RFC8505] inherits from IPv6 Neighbor Discovery for 419 mechanisms such as Stateless Address Autoconfiguration (SLAAC) and 420 Neighbor Unreachability Detection (NUD). A 6LoWPAN node is also 421 expected to be an IPv6 host per [RFC8200] which means it should 422 ignore consumed routing headers and Hop-by-Hop options; when 423 operating in a RPL network [RFC6550], it is also beneficial to 424 support IP-in-IP encapsulation [RFC9008]. The 6LoWPAN node should 425 also support [RFC8505] and use it as the default Neighbor 426 Discovery method. It is the responsibility of the deployment to 427 ensure unique global IPv6 addresses for Internet connectivity. 428 For local-only connectivity IPv6 Unique Local Address (ULA) may be 429 used. [RFC6775][RFC8505] specifies the 6LoWPAN border router 430 (6LBR), which is responsible for prefix assignment to the 6LoWPAN 431 network. A 6LBR can be connected to the Internet or to an 432 enterprise network via one of the interfaces. Please refer to 433 [RFC7668] and [RFC8105] for examples of address assignment 434 considerations. In addition, privacy considerations [RFC8065] 435 must be consulted for applicability. In certain scenarios, the 436 deployment may not support IPv6 address autoconfiguration due to 437 regulatory and business reasons and may choose to offer a separate 438 address assignment service. Address Protection for 6LoWPAN 439 Neighbor Discovery (AP-ND) [RFC8928] enables Source Address 440 Validation [RFC6620] and protects the address ownership against 441 impersonation attacks. 443 * Broadcast Avoidance: 6LoWPAN Neighbor Discovery aims at reducing 444 the amount of multicast traffic of classical Neighbor Discovery, 445 since IP-level multicast translates into L2 broadcast in many L2 446 technologies. 6LoWPAN Neighbor Discovery relies on a proactive 447 registration to avoid the use of multicast for address resolution. 448 It also uses a unicast method for Duplicate Address Detection 449 (DAD), and avoids multicast lookups from all nodes by using non- 450 onlink prefixes. Router Advertisements (RAs) are also sent in 451 unicast, in response to Router Solicitations (RSs) 453 * Host-to-Router interface: 6lo has defined registration extensions 454 for 6LoWPAN Neighbor Discovery [RFC8505]. This effort provides a 455 host-to-router interface by which a host can request its router to 456 ensure reachability for the address registered with the router. 457 Note that functionality has been developed to ensure that such a 458 host can benefit from routing services in a RPL network [RFC9010] 460 * Proxy Neighbor Discovery: Further functionality also allows a 461 device (e.g. an energy-constrained device that needs to sleep most 462 of the time) to request proxy Neighbor Discovery services from a 463 6LoWPAN Backbone Router (6BBR) [RFC8505][RFC8929]. The latter 464 federates a number of links into a multilink subnet. 466 * Header Compression: IPv6 header compression [RFC6282] is a vital 467 part of IPv6 over low power communication. Examples of header 468 compression over different link-layer specifications are found in 470 [RFC7668], [RFC8163], [RFC8105]. A generic header compression 471 technique is specified in [RFC7400]. For 6LoWPAN networks where 472 RPL is the routing protocol, there exist 6LoWPAN header 473 compression extensions which allow to compress also the RPL 474 artifacts used when forwarding packets in the route-over mesh 475 [RFC8138] [RFC9035] 477 * Security and Encryption: Though 6LoWPAN basic specifications do 478 not address security at the network layer, the assumption is that 479 L2 security must be present. In addition, application-level 480 security is highly desirable. The working groups [IETF_ace] and 481 [IETF_core] should be consulted for application and transport 482 level security. 6lo working group is working on address 483 authentication [RFC8928] and secure bootstrapping is also being 484 discussed at IETF. However, there may be different levels of 485 security available in a deployment through other standards such as 486 hardware-level security or certificates for initial booting 487 process. Encryption is important if the implementation can afford 488 it. 490 * Additional processing: [RFC8066] defines guidelines for ESC 491 dispatch octets use in the 6LoWPAN header. An implementation may 492 take advantage of ESC header to offer a deployment specific 493 processing of 6LoWPAN packets. 495 4. 6lo Deployment Scenarios 497 4.1. Wi-SUN usage of 6lo in network layer 499 Wireless Smart Ubiquitous Network (Wi-SUN)[Wi-SUN] is a technology 500 based on the IEEE Std 802.15.4g standard. Wi-SUN networks support 501 star and mesh topologies, as well as hybrid star/mesh deployments, 502 but these are typically laid out in a mesh topology where each node 503 relays data for the network to provide network connectivity. Wi-SUN 504 networks are deployed on both powered and battery-operated devices 505 [RFC8376]. 507 The main application domains targeted by Wi-SUN are smart utility and 508 smart city networks. This includes, but is not limited to the 509 following applications: 511 * Advanced Metering Infrastructure 513 * Distribution Automation 515 * Home Energy Management 517 * Infrastructure Management 518 * Intelligent Transportation Systems 520 * Smart Street Lighting 522 * Agriculture 524 * Structural health (bridges, buildings) 526 * Monitoring and Asset Management 528 * Smart Thermostats, Air Conditioning and Heat Controls 530 * Energy Usage Information Displays 532 The Wi-SUN Alliance Field Area Network (FAN) covers primarily outdoor 533 networks, and its specification is oriented towards meeting the more 534 rigorous challenges of these environments. It has the following 535 features: 537 * Open standards based on IEEE802, IETF, TIA, ETSI 539 * Architecture based on an IPv6 frequency hopping wireless mesh 540 network with enterprise-level security 542 * Simple infrastructure of low cost, low complexity 544 * Enhanced network robustness, reliability, and resilience to 545 interference, due to high redundancy and frequency hopping 547 * Enhanced scalability, long range, and energy friendliness 549 * Supports multiple global license-exempt sub-GHz bands 551 * Multi-vendor interoperability 553 * Very low power modes in development permitting long term battery 554 operation of network nodes 556 The Wi-SUN FAN specification defines an IPv6-based protocol suite 557 including TCP/UDP, IPv6, 6lo adaptation layer, DHCPv6 for IPv6 558 address management, RPL, and ICMPv6. 560 4.2. Thread usage of 6lo in network layer 562 Thread is an IPv6-based networking protocol stack built on open 563 standards, designed for smart home environments, and based on low- 564 power IEEE Std 802.15.4 mesh networks. Because of its IPv6 565 foundation, Thread can support existing popular application layers 566 and IoT platforms, provide end-to-end security, ease development and 567 enable flexible and future-proof designs [Thread]. 569 The Thread specification uses the IEEE Std 802.15.4 [IEEE802154] 570 physical and MAC layers operating at 250 kbps in the 2.4 GHz band. 572 Thread devices use 6LoWPAN, as defined in [RFC4944][RFC6282], for 573 transmission of IPv6 Packets over IEEE Std 802.15.4 networks. Header 574 compression is used within the Thread network and devices 575 transmitting messages compress the IPv6 header to minimize the size 576 of the transmitted packet. The mesh header is supported for link- 577 layer (i.e., mesh under) forwarding. The mesh header as used in 578 Thread also allows efficient end-to-end fragmentation of messages 579 rather than the hop-by-hop fragmentation specified in [RFC4944]. 580 Mesh under routing in Thread is based on a distance vector protocol 581 in a full mesh topology. 583 4.3. G3-PLC usage of 6lo in network layer 585 G3-PLC [G3-PLC] is a narrowband PLC technology that is based on the 586 ITU-T G.9903 Recommendation [G.9903]. G3-PLC supports multi-hop mesh 587 network topology, and facilitates highly-reliable, long-range 588 communication. With the abilities to support IPv6 and to cross 589 transformers, G3-PLC is regarded as one of the next-generation 590 narrowband PLC technologies. G3-PLC has got massive deployments over 591 several countries, e.g. Japan and France. 593 The main application domains targeted by G3-PLC are smart grid and 594 smart cities. This includes, but is not limited to the following 595 applications: 597 * Smart Metering 599 * Vehicle-to-Grid Communication 601 * Demand Response 603 * Distribution Automation 605 * Home/Building Energy Management Systems 607 * Smart Street Lighting 608 * Advanced Metering Infrastructure (AMI) backbone network 610 * Wind/Solar Farm Monitoring 612 In the G3-PLC specification, the 6lo adaption layer utilizes the 613 6LoWPAN functions (e.g. header compression, fragmentation and 614 reassembly). However, due to the different characteristics of the 615 PLC media, the 6LoWPAN adaptation layer cannot perfectly fulfill the 616 requirements [I-D.ietf-6lo-plc]. The ESC dispatch type is used in 617 the G3-PLC to provide native mesh routing and bootstrapping 618 functionalities [RFC8066]. 620 4.4. Netricity usage of 6lo in network layer 622 The Netricity program in HomePlug Powerline Alliance [NETRICITY] 623 promotes the adoption of products built on the IEEE Std 1901.2 low- 624 frequency narrowband PLC standard, which provides for urban and long 625 distance communications and propagation through transformers of the 626 distribution network using frequencies below 500 kHz. The technology 627 also addresses requirements that assure communication privacy and 628 secure networks. 630 The main application domains targeted by Netricity are smart grid and 631 smart cities. This includes, but is not limited to the following 632 applications: 634 * Utility grid modernization 636 * Distribution automation 638 * Meter-to-Grid connectivity 640 * Micro-grids 642 * Grid sensor communications 644 * Load control 646 * Demand response 648 * Net metering 650 * Street Lighting control 652 * Photovoltaic panel monitoring 653 Netricity system architecture is based on the physical and MAC layers 654 of IEEE Std 1901.2 PLC standard. Regarding the 6lo adaptation layer 655 and IPv6 network layer, Netricity utilizes IPv6 protocol suite 656 including 6lo/6LoWPAN header compression, DHCPv6 for IP address 657 management, RPL routing protocol, ICMPv6, and unicast/multicast 658 forwarding. Note that the L3 routing in Netricity uses RPL in non- 659 storing mode with the MRHOF objective function based on the own 660 defined Estimated Transmission Time (ETT) metric. 662 5. 6lo Use Case Examples 664 As IPv6 stacks for constrained node networks use a variation of the 665 6LoWPAN stack applied to each particular link layer technology, 666 various 6lo use cases can be provided. In this section, various 6lo 667 use cases which are based on different link layer technologies are 668 described. 670 5.1. Use case of ITU-T G.9959: Smart Home 672 Z-Wave is one of the main technologies that may be used to enable 673 smart home applications. Born as a proprietary technology, Z-Wave 674 was specifically designed for this particular use case. Recently, 675 the Z-Wave radio interface (physical and MAC layers) has been 676 standardized as the ITU-T G.9959 specification. 678 Example: Use of ITU-T G.9959 for Home Automation 680 Variety of home devices (e.g. light dimmers/switches, plugs, 681 thermostats, blinds/curtains and remote controls) are augmented with 682 ITU-T G.9959 interfaces. A user may turn on/off or may control home 683 appliances by pressing a wall switch or by pressing a button in a 684 remote control. Scenes may be programmed, so that after a given 685 event, the home devices adopt a specific configuration. Sensors may 686 also periodically send measurements of several parameters (e.g. gas 687 presence, light, temperature, humidity, etc.) which are collected at 688 a sink device, or may generate commands for actuators (e.g. a smoke 689 sensor may send an alarm message to a safety system). 691 The devices involved in the described scenario are nodes of a network 692 that follows the mesh topology, which is suitable for path diversity 693 to face indoor multipath propagation issues. The multihop paradigm 694 allows end-to-end connectivity when direct range communication is not 695 possible. Security support is required, specially for safety-related 696 communication. When a user interaction (e.g. a button press) 697 triggers a message that encapsulates a command, if the message is 698 lost, the user may have to perform further interactions to achieve 699 the desired effect (e.g. turning off a light). A reaction to a user 700 interaction will be perceived by the user as immediate as long as the 701 reaction takes place within 0.5 seconds [RFC5826]. 703 5.2. Use case of Bluetooth LE: Smartphone-based Interaction 705 The key feature behind the current high Bluetooth LE momentum is its 706 support in a large majority of smartphones in the market. Bluetooth 707 LE can be used to allow the interaction between the smartphone and 708 surrounding sensors or actuators. Furthermore, Bluetooth LE is also 709 the main radio interface currently available in wearables. Since a 710 smartphone typically has several radio interfaces that provide 711 Internet access, such as Wi-Fi or 4G, the smartphone can act as a 712 gateway for nearby devices such as sensors, actuators or wearables. 713 Bluetooth LE may be used in several domains, including healthcare, 714 sports/wellness and home automation. 716 Example: Use of Bluetooth LE-based Body Area Network for fitness 718 A person wears a smartwatch for fitness purposes. The smartwatch has 719 several sensors (e.g. heart rate, accelerometer, gyrometer, GPS, 720 temperature, etc.), a display, and a Bluetooth LE radio interface. 721 The smartwatch can show fitness-related statistics on its display. 722 However, when a paired smartphone is in the range of the smartwatch, 723 the latter can report almost real-time measurements of its sensors to 724 the smartphone, which can forward the data to a cloud service on the 725 Internet. 6lo enables this use case by providing efficient end-to-end 726 IPv6 support. In addition, the smartwatch can receive notifications 727 (e.g. alarm signals) from the cloud service via the smartphone. On 728 the other hand, the smartphone may locally generate messages for the 729 smartwatch, such as e-mail reception or calendar notifications. 731 The functionality supported by the smartwatch may be complemented by 732 other devices such as other on-body sensors, wireless headsets or 733 head-mounted displays. All such devices may connect to the 734 smartphone creating a star topology network whereby the smartphone is 735 the central component. Support for extended network topologies (e.g. 736 mesh networks) is being developed as of the writing. 738 5.3. Use case of DECT-ULE: Smart Home 740 DECT is a technology widely used for wireless telephone 741 communications in residential scenarios. Since DECT-ULE is a low- 742 power variant of DECT, DECT-ULE can be used to connect constrained 743 devices such as sensors and actuators to a Fixed Part, a device that 744 typically acts as a base station for wireless telephones. Therefore, 745 DECT-ULE is specially suitable for the connected home space in 746 application areas such as home automation, smart metering, safety, 747 healthcare, etc. Since DECT-ULE uses dedicated bandwidth, it avoids 748 the coexistence issues suffered by other technologies that use e.g. 749 ISM frequency bands. 751 Example: Use of DECT-ULE for Smart Metering 753 The smart electricity meter of a home is equipped with a DECT-ULE 754 transceiver. This device is in the coverage range of the Fixed Part 755 of the home. The Fixed Part can act as a router connected to the 756 Internet. This way, the smart meter can transmit electricity 757 consumption readings through the DECT-ULE link with the Fixed Part, 758 and the latter can forward such readings to the utility company using 759 Wide Area Network (WAN) links. The meter can also receive queries 760 from the utility company or from an advanced energy control system 761 controlled by the user, which may also be connected to the Fixed Part 762 via DECT-ULE. 764 5.4. Use case of MS/TP: Building Automation Networks 766 The primary use case for IPv6 over MS/TP (6LoBAC) is in building 767 automation networks. [BACnet] is the open international standard 768 protocol for building automation, and MS/TP is defined in [BACnet] 769 Clause 9. MS/TP was designed to be a low cost multi-drop field bus 770 to inter-connect the most numerous elements (sensors and actuators) 771 of a building automation network to their controllers. A key aspect 772 of 6LoBAC is that it is designed to co-exist with BACnet MS/TP on the 773 same link, easing the ultimate transition of some BACnet networks to 774 native end-to-end IPv6 transport protocols. New applications for 775 6LoBAC may be found in other domains where low cost, long distance, 776 and low latency are required. Note that BACnet comprises various 777 networking solutions other than MS/TP, including the recently emerged 778 BACnet IP. However, the latter is based on high speed Ethernet 779 infrastructure, and thus it falls outside of the constrained node 780 network scope. 782 Example: Use of 6LoBAC in Building Automation Networks 783 The majority of installations for MS/TP are for "terminal" or 784 "unitary" controllers, i.e. single zone or room controllers that may 785 connect to HVAC or other controls such as lighting or blinds. The 786 economics of daisy-chaining a single twisted-pair between multiple 787 devices is often preferred over home-run Cat-5 style wiring. 789 A multi-zone controller might be implemented as an IP router between 790 a traditional Ethernet link and several 6LoBAC links, fanning out to 791 multiple terminal controllers. 793 The superior distance capabilities of MS/TP (~1 km) compared to other 794 6lo media may suggest its use in applications to connect remote 795 devices to the nearest building infrastructure. For example, remote 796 pumping or measuring stations with moderate bandwidth requirements 797 can benefit from the low cost and robust capabilities of MS/TP over 798 other wired technologies such as DSL, and without the line-of-sight 799 restrictions or hop-by-hop latency of many low cost wireless 800 solutions. 802 5.5. Use case of NFC: Alternative Secure Transfer 804 In different applications, a variety of secured data can be handled 805 and transferred. Depending on the security level of the data, 806 different transfer methods can be alternatively selected. 808 Example: Use of NFC for Secure Transfer in Healthcare Services with 809 Tele-Assistance 811 A senior citizen who lives alone wears one to several wearable 6lo 812 devices to measure heartbeat, pulse rate, etc. The 6lo devices are 813 densely installed at home for movement detection. A 6LBR at home 814 will send the sensed information to a connected healthcare center. 815 Portable base stations with LCDs may be used to check the data at 816 home, as well. Data is gathered in both periodic and event-driven 817 fashion. In this application, event-driven data can be very time- 818 critical. In addition, privacy also becomes a serious issue in this 819 case, as the sensed data is very personal. 821 While the senior citizen is provided audio and video healthcare 822 services by a tele-assistance based on LTE connections, the senior 823 citizen can alternatively use NFC connections to transfer the 824 personal sensed data to the tele-assistance. Hidden hackers can 825 overhear the data based on the LTE connection, but they cannot gather 826 the personal data over the NFC connection. 828 5.6. Use case of PLC: Smart Grid 830 The smart grid concept is based on deploying numerous operational and 831 energy measuring sub-systems in an electricity grid system. It 832 comprises multiple administrative levels/segments to provide 833 connectivity among these numerous components. Last mile connectivity 834 is established over the Low Voltage (LV) segment, whereas 835 connectivity over electricity distribution takes place in the High 836 Voltage (HV) segment. Smart grid systems include Advanced Metering 837 Infrastructure (AMI), Demand Response (DR), Home Energy Management 838 System (HEMS), Wide Area Situational Awareness (WASA), among others. 840 Although other wired and wireless technologies are also used in Smart 841 Grid, PLC enjoys the advantage of reliable data communication over 842 electrical power lines that are already present, and the deployment 843 cost can be comparable to wireless technologies. The 6lo-related 844 scenarios for PLC mainly lie in the LV PLC networks with most 845 applications in the area of Advanced Metering Infrastructure, 846 Vehicle-to-Grid communications, in-home energy management and smart 847 street lighting. 849 Example: Use of PLC for Advanced Metering Infrastructure 851 Household electricity meters transmit time-based data of electric 852 power consumption through PLC. Data concentrators receive all the 853 meter data in their corresponding living districts and send them to 854 the Meter Data Management System (MDMS) through WAN network (e.g. 855 Medium-Voltage PLC, Ethernet or GPRS) for storage and analysis. Two- 856 way communications are enabled which means smart meters can do 857 actions like notification of electricity charges according to the 858 commands from the utility company. 860 With the existing power line infrastructure as communication medium, 861 cost on building up the PLC network is naturally saved, and more 862 importantly, labor operational costs can be minimized from a long- 863 term perspective. Furthermore, this AMI application speeds up 864 electricity charge, reduces losses by restraining power theft and 865 helps to manage the health of the grid based on line loss analysis. 867 Example: Use of PLC (IEEE Std 1901.1) for WASA in Smart Grid 869 Many sub-systems of Smart Grid require low data rate and narrowband 870 variants (e.g., IEEE Std 1901.1) of PLC fulfill such requirements. 871 Recently, more complex scenarios are emerging that require higher 872 data rates. 874 WASA sub-system is an appropriate example that collects large amount 875 of information about the current state of the grid over wide area 876 from electric substations as well as power transmission lines. The 877 collected feedback is used for monitoring, controlling and protecting 878 all the sub-systems. 880 6. IANA Considerations 882 There are no IANA considerations related to this document. 884 7. Security Considerations 886 Security considerations are not directly applicable to this document. 887 For the use cases, the security requirements described in the 888 protocol specifications apply. 890 8. Acknowledgements 892 Carles Gomez has been funded in part by the Spanish Government 893 through the Jose Castillejo CAS15/00336 grant, the TEC2016-79988-P 894 grant, and the PID2019-106808RA-I00 grant, and by Secretaria 895 d'Universitats i Recerca del Departament d'Empresa i Coneixement de 896 la Generalitat de Catalunya 2017 through grant SGR 376. His 897 contribution to this work has been carried out in part during his 898 stay as a visiting scholar at the Computer Laboratory of the 899 University of Cambridge. 901 Thomas Watteyne, Pascal Thubert, Xavier Vilajosana, Daniel Migault, 902 Jianqiang Hou, Kerry Lynn, S.V.R. Anand, and Seyed Mahdi Darroudi 903 have provided valuable feedback for this draft. 905 Das Subir and Michel Veillette have provided valuable information of 906 jupiterMesh and Paul Duffy has provided valuable information of Wi- 907 SUN for this draft. Also, Jianqiang Hou has provided valuable 908 information of G3-PLC and Netricity for this draft. Take Aanstoot, 909 Kerry Lynn, and Dave Robin have provided valuable information of MS/ 910 TP and practical use case of MS/TP for this draft. 912 Deoknyong Ko has provided relevant text of LTE-MTC and he shared his 913 experience to deploy IPv6 and 6lo technologies over LTE MTC in SK 914 Telecom. 916 9. Informative References 918 [BACnet] "ASHRAE, "BACnet-A Data Communication Protocol for 919 Building Automation and Control Networks", ANSI/ASHRAE 920 Standard 135-2016", January 2016, 921 . 924 [G.9903] "International Telecommunication Union, "Narrowband 925 orthogonal frequency division multiplexing power line 926 communication transceivers for G3-PLC networks", ITU-T 927 Recommendation", August 2017. 929 [G.9959] "International Telecommunication Union, "Short range 930 narrow-band digital radiocommunication transceivers - PHY 931 and MAC layer specifications", ITU-T Recommendation", 932 January 2015. 934 [G3-PLC] "G3-PLC Alliance", . 936 [IEEE1901] "IEEE Standard, IEEE Std 1901-2010 - IEEE Standard for 937 Broadband over Power Line Networks: Medium Access Control 938 and Physical Layer Specifications", 2010, 939 . 942 [IEEE1901.1] 943 "IEEE Standard, IEEE Std 1901.1-2018 - IEEE Standard for 944 Medium Frequency (less than 12 MHz) Power Line 945 Communications for Smart Grid Applications", 2018, 946 . 948 [IEEE1901.2] 949 "IEEE Standard, IEEE Std 1901.2-2013 - IEEE Standard for 950 Low-Frequency (less than 500 kHz) Narrowband Power Line 951 Communications for Smart Grid Applications", 2013, 952 . 955 [IEEE802154] 956 IEEE standard for Information Technology, "IEEE Standard 957 for Low-Rate Wireless Networks". 959 [IEEE802159] 960 IEEE standard for Information Technology, "IEEE Std 961 802.15.9-2016 - IEEE Recommended Practice for Transport of 962 Key Management Protocol (KMP) Datagrams". 964 [I-D.ietf-6lo-nfc] 965 Choi, Y., Hong, Y., Youn, J., Kim, D., and J. Choi, 966 "Transmission of IPv6 Packets over Near Field 967 Communication", Work in Progress, Internet-Draft, draft- 968 ietf-6lo-nfc-17, 23 August 2020, . 971 [I-D.ietf-6lo-plc] 972 Hou, J., Liu, B. R., Hong, Y., Tang, X., and C. E. 973 Perkins, "Transmission of IPv6 Packets over PLC Networks", 974 Work in Progress, Internet-Draft, draft-ietf-6lo-plc-09, 975 10 January 2022, . 978 [IETF_6lo] "IETF IPv6 over Networks of Resource-constrained Nodes 979 (6lo) working group", 980 . 982 [IETF_ace] "IETF Authentication and Authorization for Constrained 983 Environments (ace) working group", 984 . 986 [IETF_core] 987 "IETF Constrained RESTful Environments (core) working 988 group", . 990 [Wi-SUN] "Wi-SUN Alliance", . 992 [Thread] "Thread Group", . 994 [NETRICITY] 995 "Netricity program in HomePlug Powerline Alliance", 996 . 998 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 999 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 1000 DOI 10.17487/RFC4861, September 2007, 1001 . 1003 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 1004 Address Autoconfiguration", RFC 4862, 1005 DOI 10.17487/RFC4862, September 2007, 1006 . 1008 [RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6 1009 over Low-Power Wireless Personal Area Networks (6LoWPANs): 1010 Overview, Assumptions, Problem Statement, and Goals", 1011 RFC 4919, DOI 10.17487/RFC4919, August 2007, 1012 . 1014 [RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, 1015 "Transmission of IPv6 Packets over IEEE 802.15.4 1016 Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007, 1017 . 1019 [RFC5826] Brandt, A., Buron, J., and G. Porcu, "Home Automation 1020 Routing Requirements in Low-Power and Lossy Networks", 1021 RFC 5826, DOI 10.17487/RFC5826, April 2010, 1022 . 1024 [RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6 1025 Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, 1026 DOI 10.17487/RFC6282, September 2011, 1027 . 1029 [RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J., 1030 Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur, 1031 JP., and R. Alexander, "RPL: IPv6 Routing Protocol for 1032 Low-Power and Lossy Networks", RFC 6550, 1033 DOI 10.17487/RFC6550, March 2012, 1034 . 1036 [RFC6568] Kim, E., Kaspar, D., and JP. Vasseur, "Design and 1037 Application Spaces for IPv6 over Low-Power Wireless 1038 Personal Area Networks (6LoWPANs)", RFC 6568, 1039 DOI 10.17487/RFC6568, April 2012, 1040 . 1042 [RFC6606] Kim, E., Kaspar, D., Gomez, C., and C. Bormann, "Problem 1043 Statement and Requirements for IPv6 over Low-Power 1044 Wireless Personal Area Network (6LoWPAN) Routing", 1045 RFC 6606, DOI 10.17487/RFC6606, May 2012, 1046 . 1048 [RFC6620] Nordmark, E., Bagnulo, M., and E. Levy-Abegnoli, "FCFS 1049 SAVI: First-Come, First-Served Source Address Validation 1050 Improvement for Locally Assigned IPv6 Addresses", 1051 RFC 6620, DOI 10.17487/RFC6620, May 2012, 1052 . 1054 [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. 1055 Bormann, "Neighbor Discovery Optimization for IPv6 over 1056 Low-Power Wireless Personal Area Networks (6LoWPANs)", 1057 RFC 6775, DOI 10.17487/RFC6775, November 2012, 1058 . 1060 [RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for 1061 Constrained-Node Networks", RFC 7228, 1062 DOI 10.17487/RFC7228, May 2014, 1063 . 1065 [RFC7400] Bormann, C., "6LoWPAN-GHC: Generic Header Compression for 1066 IPv6 over Low-Power Wireless Personal Area Networks 1067 (6LoWPANs)", RFC 7400, DOI 10.17487/RFC7400, November 1068 2014, . 1070 [RFC7428] Brandt, A. and J. Buron, "Transmission of IPv6 Packets 1071 over ITU-T G.9959 Networks", RFC 7428, 1072 DOI 10.17487/RFC7428, February 2015, 1073 . 1075 [RFC7668] Nieminen, J., Savolainen, T., Isomaki, M., Patil, B., 1076 Shelby, Z., and C. Gomez, "IPv6 over BLUETOOTH(R) Low 1077 Energy", RFC 7668, DOI 10.17487/RFC7668, October 2015, 1078 . 1080 [RFC8036] Cam-Winget, N., Ed., Hui, J., and D. Popa, "Applicability 1081 Statement for the Routing Protocol for Low-Power and Lossy 1082 Networks (RPL) in Advanced Metering Infrastructure (AMI) 1083 Networks", RFC 8036, DOI 10.17487/RFC8036, January 2017, 1084 . 1086 [RFC8065] Thaler, D., "Privacy Considerations for IPv6 Adaptation- 1087 Layer Mechanisms", RFC 8065, DOI 10.17487/RFC8065, 1088 February 2017, . 1090 [RFC8066] Chakrabarti, S., Montenegro, G., Droms, R., and J. 1091 Woodyatt, "IPv6 over Low-Power Wireless Personal Area 1092 Network (6LoWPAN) ESC Dispatch Code Points and 1093 Guidelines", RFC 8066, DOI 10.17487/RFC8066, February 1094 2017, . 1096 [RFC8105] Mariager, P., Petersen, J., Ed., Shelby, Z., Van de Logt, 1097 M., and D. Barthel, "Transmission of IPv6 Packets over 1098 Digital Enhanced Cordless Telecommunications (DECT) Ultra 1099 Low Energy (ULE)", RFC 8105, DOI 10.17487/RFC8105, May 1100 2017, . 1102 [RFC8138] Thubert, P., Ed., Bormann, C., Toutain, L., and R. Cragie, 1103 "IPv6 over Low-Power Wireless Personal Area Network 1104 (6LoWPAN) Routing Header", RFC 8138, DOI 10.17487/RFC8138, 1105 April 2017, . 1107 [RFC8163] Lynn, K., Ed., Martocci, J., Neilson, C., and S. 1108 Donaldson, "Transmission of IPv6 over Master-Slave/Token- 1109 Passing (MS/TP) Networks", RFC 8163, DOI 10.17487/RFC8163, 1110 May 2017, . 1112 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1113 (IPv6) Specification", STD 86, RFC 8200, 1114 DOI 10.17487/RFC8200, July 2017, 1115 . 1117 [RFC8352] Gomez, C., Kovatsch, M., Tian, H., and Z. Cao, Ed., 1118 "Energy-Efficient Features of Internet of Things 1119 Protocols", RFC 8352, DOI 10.17487/RFC8352, April 2018, 1120 . 1122 [RFC8376] Farrell, S., Ed., "Low-Power Wide Area Network (LPWAN) 1123 Overview", RFC 8376, DOI 10.17487/RFC8376, May 2018, 1124 . 1126 [RFC8505] Thubert, P., Ed., Nordmark, E., Chakrabarti, S., and C. 1127 Perkins, "Registration Extensions for IPv6 over Low-Power 1128 Wireless Personal Area Network (6LoWPAN) Neighbor 1129 Discovery", RFC 8505, DOI 10.17487/RFC8505, November 2018, 1130 . 1132 [RFC8928] Thubert, P., Ed., Sarikaya, B., Sethi, M., and R. Struik, 1133 "Address-Protected Neighbor Discovery for Low-Power and 1134 Lossy Networks", RFC 8928, DOI 10.17487/RFC8928, November 1135 2020, . 1137 [RFC8929] Thubert, P., Ed., Perkins, C.E., and E. Levy-Abegnoli, 1138 "IPv6 Backbone Router", RFC 8929, DOI 10.17487/RFC8929, 1139 November 2020, . 1141 [RFC9008] Robles, M.I., Richardson, M., and P. Thubert, "Using RPI 1142 Option Type, Routing Header for Source Routes, and IPv6- 1143 in-IPv6 Encapsulation in the RPL Data Plane", RFC 9008, 1144 DOI 10.17487/RFC9008, April 2021, 1145 . 1147 [RFC9010] Thubert, P., Ed. and M. Richardson, "Routing for RPL 1148 (Routing Protocol for Low-Power and Lossy Networks) 1149 Leaves", RFC 9010, DOI 10.17487/RFC9010, April 2021, 1150 . 1152 [RFC9035] Thubert, P., Ed. and L. Zhao, "A Routing Protocol for Low- 1153 Power and Lossy Networks (RPL) Destination-Oriented 1154 Directed Acyclic Graph (DODAG) Configuration Option for 1155 the 6LoWPAN Routing Header", RFC 9035, 1156 DOI 10.17487/RFC9035, April 2021, 1157 . 1159 [RFC9159] Gomez, C., Darroudi, S.M., Savolainen, T., and M. Spoerk, 1160 "IPv6 Mesh over BLUETOOTH(R) Low Energy Using the Internet 1161 Protocol Support Profile (IPSP)", RFC 9159, 1162 DOI 10.17487/RFC9159, December 2021, 1163 . 1165 [TIA-485-A] 1166 "TIA, "Electrical Characteristics of Generators and 1167 Receivers for Use in Balanced Digital Multipoint Systems", 1168 TIA-485-A (Revision of TIA-485)", March 2003, 1169 . 1172 Appendix A. Design Space Dimensions for 6lo Deployment 1174 The [RFC6568] lists the dimensions used to describe the design space 1175 of wireless sensor networks in the context of the 6LoWPAN working 1176 group. The design space is already limited by the unique 1177 characteristics of a LoWPAN (e.g. low power, short range, low bit 1178 rate). In [RFC6568], the following design space dimensions are 1179 described: Deployment, Network size, Power source, Connectivity, 1180 Multi-hop communication, Traffic pattern, Mobility, Quality of 1181 Service (QoS). However, in this document, the following design space 1182 dimensions are considered: 1184 * Deployment/Bootstrapping: 6lo nodes can be connected randomly, or 1185 in an organized manner. The bootstrapping has different 1186 characteristics for each link layer technology. 1188 * Topology: Topology of 6lo networks may inherently follow the 1189 characteristics of each link layer technology. Point-to-point, 1190 star, tree or mesh topologies can be configured, depending on the 1191 link layer technology considered. 1193 * L2-Mesh or L3-Mesh: L2-mesh and L3-mesh may inherently follow the 1194 characteristics of each link layer technology. Some link layer 1195 technologies may support L2-mesh and some may not support. 1197 * Multi-link subnet, single subnet: The selection of multi-link 1198 subnet and single subnet depends on connectivity and the number of 1199 6lo nodes. 1201 * Data rate: Typically, the link layer technologies of 6lo have low 1202 rate of data transmission. But, by adjusting the MTU, it can 1203 deliver higher upper layer data rate. 1205 * Buffering requirements: Some 6lo use case may require more data 1206 rate than the link layer technology support. In this case, a 1207 buffering mechanism to manage the data is required. 1209 * Security and Privacy Requirements: Some 6lo use case can involve 1210 transferring some important and personal data between 6lo nodes. 1211 In this case, high-level security support is required. 1213 * Mobility across 6lo networks and subnets: The movement of 6lo 1214 nodes depends on the 6lo use case. If the 6lo nodes can move or 1215 moved around, a mobility management mechanism is required. 1217 * Time synchronization requirements: The requirement of time 1218 synchronization of the upper layer service is dependent on the 6lo 1219 use case. For some 6lo use case related to health service, the 1220 measured data must be recorded with exact time and must be 1221 transferred with time synchronization. 1223 * Reliability and QoS: Some 6lo use case requires high reliability, 1224 for example real-time service or health-related services. 1226 * Traffic patterns: 6lo use cases may involve various traffic 1227 patterns. For example, some 6lo use case may require short data 1228 length and random transmission. Some 6lo use case may require 1229 continuous data and periodic data transmission. 1231 * Security Bootstrapping: Without the external operations, 6lo nodes 1232 must have the security bootstrapping mechanism. 1234 * Power use strategy: to enable certain use cases, there may be 1235 requirements on the class of energy availability and the strategy 1236 followed for using power for communication [RFC7228]. Each link 1237 layer technology defines a particular power use strategy which may 1238 be tuned [RFC8352]. Readers are expected to be familiar with 1239 [RFC7228] terminology. 1241 * Update firmware requirements: Most 6lo use cases will need a 1242 mechanism for updating firmware. In these cases support for over 1243 the air updates are required, probably in a broadcast mode when 1244 bandwidth is low and the number of identical devices is high. 1246 * Wired vs. Wireless: Plenty of 6lo link layer technologies are 1247 wireless, except MS/TP and PLC. The selection of wired or 1248 wireless link layer technology is mainly dependent on the 1249 requirement of 6lo use cases and the characteristics of wired/ 1250 wireless technologies. For example, some 6lo use cases may 1251 require easy and quick deployment, whereas others may need a 1252 continuous source of power. 1254 Authors' Addresses 1256 Yong-Geun Hong 1257 Daejeon University 1258 62 Daehak-ro, Dong-gu 1259 Daejeon 1261 Phone: +82 42 280 4841 1262 Email: yonggeun.hong@gmail.com 1264 Carles Gomez 1265 Universitat Politecnica de Catalunya/Fundacio i2cat 1266 C/Esteve Terradas, 7 1267 08860 Castelldefels 1268 Spain 1270 Email: carlesgo@entel.upc.edu 1272 Younghwan Choi 1273 ETRI 1274 218 Gajeongno, Yuseong 1275 Daejeon 1277 Phone: +82 42 860 1429 1278 Email: yhc@etri.re.kr 1279 Abdur Rashid Sangi 1280 Huaiyin Institute of Technology 1281 No.89 North Beijing Road, Qinghe District 1282 Huaian 1283 223001 1284 P.R. China 1286 Email: sangi_bahrian@yahoo.com 1288 Samita Chakrabarti 1289 San Jose, CA, 1290 United States of America 1292 Email: samitac.ietf@gmail.com