idnits 2.17.00 (12 Aug 2021) /tmp/idnits14858/draft-thubert-6man-flow-label-for-rpl-01.txt: 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: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The exact meaning of the all-uppercase expression 'MAY NOT' is not defined in RFC 2119. If it is intended as a requirements expression, it should be rewritten using one of the combinations defined in RFC 2119; otherwise it should not be all-uppercase. == The expression 'MAY NOT', while looking like RFC 2119 requirements text, is not defined in RFC 2119, and should not be used. Consider using 'MUST NOT' instead (if that is what you mean). Found 'MAY NOT' in this paragraph: This specification also allows that regardless of its original setting, a a root of a RPL domain MAY set low Label of IPv6 packets that exits the RPL domain MAY be set by the RPL, in a manner that SHOULD conform the prescriptions in [RFC6437], and that a source in the RPL domain MAY NOT expect that its setting of the Flow Label be preserved end-to-end. From there, the capability by RPL routers inside the LLN to alter a non-zero Flow Label between the source and the root is another minor deviation to [RFC6437] that is also acceptable since it is transparent to the core of the Internet. -- The document date (May 13, 2014) is 2930 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) -- Possible downref: Non-RFC (?) normative reference: ref. 'IEEE802154' ** Obsolete normative reference: RFC 2460 (Obsoleted by RFC 8200) == Outdated reference: draft-ietf-6tisch-architecture has been published as RFC 9030 == Outdated reference: draft-ietf-6tisch-tsch has been published as RFC 7554 == Outdated reference: A later version (-08) exists of draft-thubert-6lo-forwarding-fragments-01 Summary: 1 error (**), 0 flaws (~~), 5 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 6MAN P. Thubert, Ed. 3 Internet-Draft Cisco 4 Intended status: Standards Track May 13, 2014 5 Expires: November 14, 2014 7 The IPv6 Flow Label within a RPL domain 8 draft-thubert-6man-flow-label-for-rpl-01 10 Abstract 12 This document present how the Flow Label can be used inside a RPL 13 domain as a replacement to the RPL option and provides rules for the 14 root to set and reset the Flow Label when forwarding between the 15 inside of RPL domain and the larger Internet, in both direction. 16 This new operation saves 44 bits in each frame, and an eventual IP- 17 in-IP encapsulation within the RPL domain that is required for all 18 packets that reach outside of the RPL domain. 20 Status of This Memo 22 This Internet-Draft is submitted in full conformance with the 23 provisions of BCP 78 and BCP 79. 25 Internet-Drafts are working documents of the Internet Engineering 26 Task Force (IETF). Note that other groups may also distribute 27 working documents as Internet-Drafts. The list of current Internet- 28 Drafts is at http://datatracker.ietf.org/drafts/current/. 30 Internet-Drafts are draft documents valid for a maximum of six months 31 and may be updated, replaced, or obsoleted by other documents at any 32 time. It is inappropriate to use Internet-Drafts as reference 33 material or to cite them other than as "work in progress." 35 This Internet-Draft will expire on November 14, 2014. 37 Copyright Notice 39 Copyright (c) 2014 IETF Trust and the persons identified as the 40 document authors. All rights reserved. 42 This document is subject to BCP 78 and the IETF Trust's Legal 43 Provisions Relating to IETF Documents 44 (http://trustee.ietf.org/license-info) in effect on the date of 45 publication of this document. Please review these documents 46 carefully, as they describe your rights and restrictions with respect 47 to this document. Code Components extracted from this document must 48 include Simplified BSD License text as described in Section 4.e of 49 the Trust Legal Provisions and are provided without warranty as 50 described in the Simplified BSD License. 52 Table of Contents 54 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 55 1.1. On Wasted Energy . . . . . . . . . . . . . . . . . . . . 3 56 1.2. LLN flows . . . . . . . . . . . . . . . . . . . . . . . . 5 57 1.3. On Compatibility With Existing Standards . . . . . . . . 6 58 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 7 59 3. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 7 60 4. Flow Label Format Within the RPL Domain . . . . . . . . . . . 8 61 5. Root Operation . . . . . . . . . . . . . . . . . . . . . . . 8 62 5.1. Incoming Packets . . . . . . . . . . . . . . . . . . . . 9 63 5.2. Outgoing Packets . . . . . . . . . . . . . . . . . . . . 9 64 6. RPL node Operation . . . . . . . . . . . . . . . . . . . . . 9 65 7. Security Considerations . . . . . . . . . . . . . . . . . . . 9 66 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 67 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 68 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 69 10.1. Normative References . . . . . . . . . . . . . . . . . . 10 70 10.2. Informative References . . . . . . . . . . . . . . . . . 10 71 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 11 73 1. Introduction 75 The emergence of radio technology enabled a large variety of new 76 types of devices to be interconnected, at a very low marginal cost 77 compared to wire, at any range from Near Field to interplanetary 78 distances, and in circumstances where wiring would be less than 79 practical, for instance rotating devices. 81 In particular, IEEE802.14.5 [IEEE802154] that is chartered to specify 82 PHY and MAC layers for radio Lowpower Lossy Networks (LLNs), defined 83 the TimeSlotted Channel Hopping [I-D.ietf-6tisch-tsch] (TSCH) mode of 84 operation as part of the IEEE802.15.4e MAC specification in order to 85 address Time Sensitive applications. 87 The 6TISCH architecture [I-D.ietf-6tisch-architecture] specifies the 88 operation IPv6 over TSCH wireless networks attached and synchronized 89 by backbone routers. In that model, route Computation may be 90 achieved in a centralized fashion by a Path Computation Element 91 (PCE), in a distributed fashion using the Routing Protocol for Low 92 Power and Lossy Networks [RFC6550] (RPL), or in a mixed mode. The 93 Backbone Routers may typically serve as roots for the RPL domain. 95 6TiSCH was created to simplify the adoption of IETF technology by 96 other Standard Defining Organizations (SDOs), in particular in the 97 Industrial Automation space, which already relies on variations of 98 IEEE802.15.4e TSCH for Wireless Sensor Networking. ISA100.11a 99 [ISA100.11a] is an example of such industrial WSN standard, using 100 IEEE802.15.4e over the classical IEEE802.14.5 PHY. In that case, 101 after security is applied, roughly 80 octets are available per frame 102 for IP and Payload. In order to 1) avoid fragmentation and 2) 103 conserve energy, the SDO will scrutinize any bit in the frame and 104 reject any waste. 106 The challenge to obtain the adoption of IPv6 in the original standard 107 was really to save any possible bit in the frames, including the UDP 108 checksum which was an interesting discussion on its own. This work 109 was actually one of the roots for the 6LoWPAN Header Compression 110 [RFC6282] work, which goes down to the individual bits to save space 111 in the frames for actual data, and allowed ISA100.11a to adopt IPv6. 113 1.1. On Wasted Energy 115 The design of Lowpower Lossy Networks is generally focussed on saving 116 energy, which is the most constrained resource of all. The other 117 constraints, such as the memory capacity and the duty cycling of the 118 LLN devices, derive from that primary concern. Energy is typically 119 available from batteries that are expected to last for years, or 120 scavenged from the environment in very limited quantities. Any 121 protocol that is intended for use in LLNs must be designed with the 122 primary concern of saving energy as a strict requirement. 124 The Routing Protocol for Low Power and Lossy Networks (RPL) [RFC6550] 125 specification defines a generic Distance Vector protocol that is 126 indeed designed for very low energy consumption and adapted to a 127 variety of LLNs. RPL forms Destination Oriented Directed Acyclic 128 Graphs (DODAGs) which root often acts as the Border Router to connect 129 the RPL domain to the Internet. The root is responsible to select 130 the RPL Instance that is used to forward a packet coming from the 131 Internet into the RPL domain and set the related RPL information in 132 the packets. 134 A classical RPL implementation will use the RPL Option for Carrying 135 RPL Information in Data-Plane Datagrams [RFC6553] to tag a packet 136 with the Instance ID and other information that RPL requires for its 137 operation within the RPL domain. In particular, the Rank, which is 138 the scalar metric computed by an specialized Objective Function such 139 as [RFC6552], is modified at each hop and allows to validate that the 140 packet progresses in the expected direction each upwards or downwards 141 in along the DODAG. 143 With [RFC6553] the RPL option is encoded as 6 Octets; it must be 144 placed in a Hop-by-Hop header that represents 2 additional octets for 145 a total of 8. In order to limit its range to the inside the RPL 146 domain, the Hop-by-Hop header must be added to (or removed from) 147 packets that cross the border of the RPL domain. For reasons such as 148 the capability to send ICMP errors back to the source, this operation 149 involves an extra IP-in-IP encapsulation inside the RPL domain for 150 all the packets which path is not contained within the RPL domain. 152 The 8-octets overhead is detrimental to the LLN operation, in 153 particular with regards to bandwidth and battery constraints. The 154 extra encapsulation may cause a containing frame to grow above 155 maximum frame size, leading to Layer 2 or 6LoWPAN [RFC4944] 156 fragmentation, which in turn cause even more energy spending and 157 issues discussed in the LLN Fragment Forwarding and Recovery 158 [I-D.thubert-6lo-forwarding-fragments]. 160 ------+--------- ^ 161 | Internet | 162 | | Native IPv6 163 +-----+ | 164 | | Border Router (RPL Root) ^ | ^ 165 | | | | | 166 +-----+ | | | IPv6 + 167 | | | | HbH 168 o o o o | | | headers 169 o o o o o o o o o | | | 170 o o o o o o o o o o | | | 171 o o o o o o o o o | | | 172 o o o o o o o o v v v 173 o o o o o o 174 o o o o 176 LLN 178 Figure 1: IP-in-IP Encapsulation within the LLN 180 Considering that, in the classical IEEE802.14.5 PHY that is used by 181 ISA100.11a, roughly 80 octets are available per frame after security 182 is applied, and any additional transmitted bit weights in the energy 183 consumption and drains the batteries. 185 Regrettably, [RFC6282] does not provide an efficient compression for 186 the RPL option so the cost in current implementations can not be 187 alleviated in any fashion. So even for packets that are confined 188 within the RPL domain and do not need the IP-in-IP encapsulation, the 189 use of the flow label instead of the RPL option would be a valuable 190 saving. 192 1.2. LLN flows 194 In Industrial Automation and Control Systems (IACS) [RFC5673], a 195 packet loss is usually acceptable but jitter and latency must be 196 strictly controlled as they can play a critical role in the 197 interpretation of the measured information. Sensory systems are 198 often distributed, and the control information can in fact be 199 originated from multiple sources and aggregated. In such cases, 200 related packets from multiple sources should not be load-balanced 201 along their path in the Internet. 203 In a typical LLN application, the bulk of the traffic consists of 204 small chunks of data (in the order few bytes to a few tens of bytes) 205 at a time. 4Hz is a typical loop frequency in Process Control, 206 though it can be a lot slower than that in, say, environmental 207 monitoring. The granularity of traffic from a single source is too 208 small to make a lot of sense in load balancing application. 210 As a result, it can be a requirement for related measurements from 211 multiple sources to be treated as a single flow following a same path 212 over the Internet so as to experience similar jitter and latency. 213 The traditional tuple of source, destination and ports might then not 214 be the proper indication to isolate a consistent flow. On the other 215 hand, the flow integrity can be preserved in a simple manner if the 216 setting of the Flow Label in the IPv6 header of packets outgoing a 217 RPL domain, is centralized to the root of the RPL DODAG structure, as 218 opposed to distributed across the actual sources. 220 Considering that the goal for setting the Flow Label as prescribed in 221 the IPv6 Flow Label Specification [RFC6437] is to improve load 222 balancing in the core of the Internet, it is unlikely that LLN 223 devices will consume energy to generate and then transmit a Flow 224 Label to serve outside interests and the Flow Label is generally left 225 to zero so as to be elided in the 6LoWPAN [RFC6282] compression. So 226 in a general manner the interests of the core are better served if 227 the RPL roots systematically rewrite the flow label rather than if 228 they never do. 230 For packets coming into the RPL domain from the Internet, the value 231 for setting the Flow Label as prescribed in [RFC6437] is consumed 232 once the packet has traversed the core and reaches the LLN. Then 233 again, there is little value but a high cost for the LLN in spending 234 20 bits to transport a Flow Label from the Internet over the 235 constrained network to a destination node that has no use of it. 237 1.3. On Compatibility With Existing Standards 239 All the packets from all the nodes in a same DODAG that are leaving a 240 RPL domain towards the Internet will transit via a same RPL root. 241 The RPL root segregates the Internet and the RPL domain, which 242 enables the capability to reuse the Flow Label within the RPL domain. 244 On the other hand, the operation of resetting or reusing the IPv6 245 Flow Label at the root of a RPL domain is a deviation from the IPv6 246 Flow Label Specification [RFC6437], in that it is neither the source 247 nor the first hop router that sets the final Flow Label for use 248 outside the RPL domain. 250 Additionally, using the Flow Label to transport the information that 251 is classically present in the RPL option implies that the Flow Label 252 is modified at each hop inside the RPL domain, which again is a 253 limited deviation from [RFC6437], which explicitly requires that the 254 flow label cannot be modified once set. 256 But if we consider the whole RPL domain as a large virtual host from 257 the standpoint of the rest of the Internet, the interests that lead 258 to [RFC6437], and in particular load balancing in the core of the 259 Internet, are probably better served if the root guarantees that the 260 Flow Label is set in a compliant fashion than if we rely on each 261 individual sensor that may not use it at all, or use it slightly 262 differently such as done in ISA100.11a. 264 Additionally, LLN flows can be compound flows aggregating information 265 from multiple sources. The root is an ideal place to rewrite the 266 Flow Label to a same value for a same flow across multiple sources, 267 ensuring compliance with the rules defined by [RFC6437] for use 268 outside of the RPL domain and in particular in the core of the 269 Internet. 271 It can be noted that [RFC6282] provides an efficient header 272 compression for packets that do have the Flow Label set in the IPv6 273 header. It results that the overhead for transporting the RPL 274 information can be down from 64 to 20 bits, alleviating at the same 275 time the need for IP-in-IP encapsulation. This optimization cannot 276 be ignored, and can make the difference for the adoption of RPL and 277 6TiSCH by external standard bodies. 279 This document specifies how the Flow Label can be reused within the 280 RPL domain as a replacement to the RPL option. The use of the Flow 281 Label within a RPL domain is an instance of the stateful scenarios as 282 discussed in [RFC6437] where the states include the Rank of a node 283 and the RPLInstanceID that identifies the routing topology. 285 2. Terminology 287 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 288 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 289 document are to be interpreted as described in [RFC2119]. 291 The Terminology used in this document is consistent with and 292 incorporates that described in `Terminology in Low power And Lossy 293 Networks' [RFC7102] and [RFC6550]. 295 3. Applicability 297 This specification applies to a RPL [RFC6282] domain that forms a 298 stub LLN and is connected to the Internet by and only by its RPL 299 root(s), which act(s) as Border Router(s) for the LLN. With RPL, a 300 root is the bottleneck for all the traffic between the Internet and 301 the Destination-Oriented Directed Acyclic Graph (DODAG) that it 302 serves. 304 In that context, the specification entitles a RPL root to rewrite the 305 IPv6 [RFC2460] Flow Label of all packets entering or leaving the RPL 306 domain in both directions, from and towards the Internet, regardless 307 of its original setting. This may seem contradictory with the IPv6 308 Flow Label Specification [RFC6437] which stipulates that once it is 309 set, the Flow Label is left unchanged; but the RFC also indicates a 310 violation to the rule can be accepted for compelling reasons, and 311 that security is a case justifying such a violation. This 312 specification suggests that energy-saving is another compelling 313 reason for a violation to the aforementioned rule. 315 For the compelling reason of saving energy, this specification allows 316 that regardless of its original setting, a root of a RPL domain MAY 317 reset the Flow Label of IPv6 packets entering the RPL domain to zero 318 for an optimal Header Compression by 6LoWPAN [RFC6282]. The 319 specification also allows that the root and LLN routers MAY reuse the 320 Flow Label inside the LLN for LLN purposes, such as to carry the RPL 321 Information as detailed hereafter. 323 This specification also allows that regardless of its original 324 setting, a a root of a RPL domain MAY set low Label of IPv6 packets 325 that exits the RPL domain MAY be set by the RPL, in a manner that 326 SHOULD conform the prescriptions in [RFC6437], and that a source in 327 the RPL domain MAY NOT expect that its setting of the Flow Label be 328 preserved end-to-end. From there, the capability by RPL routers 329 inside the LLN to alter a non-zero Flow Label between the source and 330 the root is another minor deviation to [RFC6437] that is also 331 acceptable since it is transparent to the core of the Internet. 333 4. Flow Label Format Within the RPL Domain 335 [RFC6550] section 11.2 specifies the fields that are to be placed 336 into the packets for the purpose of Instance Identification, as well 337 as Loop Avoidance and Detection. Those fields include an 'O', and 338 'R' and an 'F' bits, the 8-bit RPLInstanceID, and the 16-bit 339 SenderRank. SenderRank is the result of the DAGRank operation on the 340 rank of the sender, where the DAGRank operation is defined in section 341 3.5.1 as: 343 DAGRank(rank) = floor(rank/MinHopRankIncrease) 345 If MinHopRankIncrease is set to a multiple of 256, it appears that 346 the most significant 8 bits of the SenderRank will be all zeroes and 347 could be omitted. In that case, the Flow Label MAY be used as a 348 replacement to the [RFC6553] RPL option. To achieve this, the 349 SenderRank is expressed with 8 least significant bits, and the 350 information carried within the Flow Label in a packet is constructed 351 follows: 353 0 1 2 354 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 355 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 356 | |O|R|F| SenderRank | RPLInstanceID | 357 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 359 Figure 1: The RPL Flow Label 361 The first (leftmost) bit of the Flow Label is reserved and should be 362 set to zero. 364 5. Root Operation 366 [RFC6437] section 3 intentionally does not consider flow label values 367 in which any of the bits have semantic significance. However, the 368 present specification assigns semantics to various bits in the flow 369 label, destroying within the edge network that is the RPL domain the 370 property of belonging to a statistically uniform distribution that is 371 desirable in the rest of the Internet. 373 It can be noted that the rationale for the statistically uniform 374 distribution does not necessarily bring a lot of value within the RPL 375 domain. In a specific use case where it would, that value must be 376 compared with that of the battery savings in order to decide which 377 technique the deployment will use to transport the RPL information. 379 5.1. Incoming Packets 381 When routing a packet towards the RPL domain, the root applies a 382 policy to determine whether the Flow Label is to be used to carry the 383 RPL information. If so, the root MUST reset the Flow Label and then 384 it MUST set all the fields in the Flow Label as prescribed by 385 [RFC6553] using the format specified in Figure 1. In particular, the 386 root selects the Instance that will be used to forward the packet 387 within the RPL domain. 389 5.2. Outgoing Packets 391 When routing a packet outside the RPL domain, the root applies a 392 policy to determine whether the Flow Label was used to carry the RPL 393 information. If so, the root MUST reset the Flow Label. The root 394 SHOULD recompute a Flow Label following the rules prescribed by 395 [RFC6553]. In particular, the root MAY ignore the source address but 396 it SHOULD use the RPLInstanceID for the computation. 398 6. RPL node Operation 400 Depending on the policy in place, the source of a packet will decide 401 whether to use this specification to transport the RPL information in 402 the IPv6 packets. If it does, the source in the LLN SHOULD set the 403 Flow Label to zero and MUST NOT expect that the flow label will be 404 conserved end-to-end". 406 7. Security Considerations 408 Because the flow label is not protected by IPSec, it is expected that 409 Layer-2 security is deployed in the LLN where is specification is 410 applied. This is the actual best practice in LLNs, which serves in 411 particular to avoid forwarding of untrusted packets over the 412 constrained network. 414 If the link layer is secured adequately, using the Flow Label as 415 opposed to the RPL option does not create an opening for a new threat 416 compared to [RFC6553]. 418 8. IANA Considerations 420 No IANA action is required for this specification. 422 9. Acknowledgements 424 The author wishes to thank Brian Carpenter for his in-depth review 425 and constructive approach to the problem resolution. 427 10. References 429 10.1. Normative References 431 [IEEE802154] 432 IEEE standard for Information Technology, "IEEE std. 433 802.15.4, Part. 15.4: Wireless Medium Access Control (MAC) 434 and Physical Layer (PHY) Specifications for Low-Rate 435 Wireless Personal Area Networks", June 2011. 437 [ISA100.11a] 438 ISA, "ISA100, Wireless Systems for Automation", May 2008, 439 < http://www.isa.org/Community/ 440 SP100WirelessSystemsforAutomation>. 442 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 443 Requirement Levels", BCP 14, RFC 2119, March 1997. 445 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 446 (IPv6) Specification", RFC 2460, December 1998. 448 [RFC6282] Hui, J. and P. Thubert, "Compression Format for IPv6 449 Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, 450 September 2011. 452 [RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme, 453 "IPv6 Flow Label Specification", RFC 6437, November 2011. 455 [RFC6550] Winter, T., Thubert, P., Brandt, A., Hui, J., Kelsey, R., 456 Levis, P., Pister, K., Struik, R., Vasseur, JP., and R. 457 Alexander, "RPL: IPv6 Routing Protocol for Low-Power and 458 Lossy Networks", RFC 6550, March 2012. 460 [RFC6552] Thubert, P., "Objective Function Zero for the Routing 461 Protocol for Low-Power and Lossy Networks (RPL)", RFC 462 6552, March 2012. 464 [RFC6553] Hui, J. and JP. Vasseur, "The Routing Protocol for Low- 465 Power and Lossy Networks (RPL) Option for Carrying RPL 466 Information in Data-Plane Datagrams", RFC 6553, March 467 2012. 469 10.2. Informative References 471 [I-D.ietf-6tisch-architecture] 472 Thubert, P., Watteyne, T., and R. Assimiti, "An 473 Architecture for IPv6 over the TSCH mode of IEEE 474 802.15.4e", draft-ietf-6tisch-architecture-01 (work in 475 progress), February 2014. 477 [I-D.ietf-6tisch-tsch] 478 Watteyne, T., Palattella, M., and L. Grieco, "Using 479 IEEE802.15.4e TSCH in an LLN context: Overview, Problem 480 Statement and Goals", draft-ietf-6tisch-tsch-00 (work in 481 progress), November 2013. 483 [I-D.thubert-6lo-forwarding-fragments] 484 Thubert, P. and J. Hui, "LLN Fragment Forwarding and 485 Recovery", draft-thubert-6lo-forwarding-fragments-01 (work 486 in progress), February 2014. 488 [RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, 489 "Transmission of IPv6 Packets over IEEE 802.15.4 490 Networks", RFC 4944, September 2007. 492 [RFC5673] Pister, K., Thubert, P., Dwars, S., and T. Phinney, 493 "Industrial Routing Requirements in Low-Power and Lossy 494 Networks", RFC 5673, October 2009. 496 [RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and 497 Lossy Networks", RFC 7102, January 2014. 499 Author's Address 501 Pascal Thubert (editor) 502 Cisco Systems 503 Village d'Entreprises Green Side 504 400, Avenue de Roumanille 505 Batiment T3 506 Biot - Sophia Antipolis 06410 507 FRANCE 509 Phone: +33 4 97 23 26 34 510 Email: pthubert@cisco.com