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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Missing Reference: '0x01' is mentioned on line 1029, but not defined == Missing Reference: '0xFF' is mentioned on line 1029, but not defined -- Possible downref: Normative reference to a draft: ref. 'I-D.droms-6man-multicast-scopes' ** Obsolete normative reference: RFC 2460 (Obsoleted by RFC 8200) -- Obsolete informational reference (is this intentional?): RFC 4601 (Obsoleted by RFC 7761) Summary: 1 error (**), 0 flaws (~~), 3 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 ROLL J. Hui 3 Internet-Draft Cisco 4 Intended status: Standards Track R. Kelsey 5 Expires: March 02, 2014 Silicon Labs 6 August 29, 2013 8 Multicast Protocol for Low power and Lossy Networks (MPL) 9 draft-ietf-roll-trickle-mcast-05 11 Abstract 13 This document specifies the Multicast Protocol for Low power and 14 Lossy Networks (MPL) that provides IPv6 multicast forwarding in 15 constrained networks. MPL avoids the need to construct or maintain 16 any multicast forwarding topology, disseminating messages to all MPL 17 Forwarders in an MPL Domain. MPL uses the Trickle algorithm to 18 manage message transmissions for both control and data-plane 19 messages. Different Trickle parameter configurations allow MPL to 20 trade between dissemination latency and transmission efficiency. 22 Status of This Memo 24 This Internet-Draft is submitted in full conformance with the 25 provisions of BCP 78 and BCP 79. 27 Internet-Drafts are working documents of the Internet Engineering 28 Task Force (IETF). Note that other groups may also distribute 29 working documents as Internet-Drafts. The list of current Internet- 30 Drafts is at http://datatracker.ietf.org/drafts/current/. 32 Internet-Drafts are draft documents valid for a maximum of six months 33 and may be updated, replaced, or obsoleted by other documents at any 34 time. It is inappropriate to use Internet-Drafts as reference 35 material or to cite them other than as "work in progress." 37 This Internet-Draft will expire on March 02, 2014. 39 Copyright Notice 41 Copyright (c) 2013 IETF Trust and the persons identified as the 42 document authors. All rights reserved. 44 This document is subject to BCP 78 and the IETF Trust's Legal 45 Provisions Relating to IETF Documents 46 (http://trustee.ietf.org/license-info) in effect on the date of 47 publication of this document. Please review these documents 48 carefully, as they describe your rights and restrictions with respect 49 to this document. Code Components extracted from this document must 50 include Simplified BSD License text as described in Section 4.e of 51 the Trust Legal Provisions and are provided without warranty as 52 described in the Simplified BSD License. 54 Table of Contents 56 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 57 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 58 3. Applicability Statement . . . . . . . . . . . . . . . . . . . 5 59 4. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 5 60 4.1. MPL Domains . . . . . . . . . . . . . . . . . . . . . . . 5 61 4.2. Information Base Overview . . . . . . . . . . . . . . . . 6 62 4.3. Overview . . . . . . . . . . . . . . . . . . . . . . . . 6 63 4.4. Signaling Overview . . . . . . . . . . . . . . . . . . . 8 64 5. MPL Parameters and Constants . . . . . . . . . . . . . . . . 9 65 5.1. MPL Multicast Addresses . . . . . . . . . . . . . . . . . 9 66 5.2. MPL Message Types . . . . . . . . . . . . . . . . . . . . 9 67 5.3. MPL Seed Identifiers . . . . . . . . . . . . . . . . . . 9 68 5.4. MPL Forwarder Parameters . . . . . . . . . . . . . . . . 9 69 5.5. MPL Trickle Parameters . . . . . . . . . . . . . . . . . 10 70 6. Protocol Message Formats . . . . . . . . . . . . . . . . . . 11 71 6.1. MPL Option . . . . . . . . . . . . . . . . . . . . . . . 11 72 6.2. MPL Control Message . . . . . . . . . . . . . . . . . . . 13 73 6.3. MPL Seed Info . . . . . . . . . . . . . . . . . . . . . . 14 74 7. Information Base . . . . . . . . . . . . . . . . . . . . . . 15 75 7.1. Local Interface Set . . . . . . . . . . . . . . . . . . . 15 76 7.2. Domain Set . . . . . . . . . . . . . . . . . . . . . . . 15 77 7.3. Seed Set . . . . . . . . . . . . . . . . . . . . . . . . 15 78 7.4. Buffered Message Set . . . . . . . . . . . . . . . . . . 16 79 8. MPL Seed Sequence Numbers . . . . . . . . . . . . . . . . . . 16 80 9. MPL Data Messages . . . . . . . . . . . . . . . . . . . . . . 17 81 9.1. MPL Data Message Generation . . . . . . . . . . . . . . . 17 82 9.2. MPL Data Message Transmission . . . . . . . . . . . . . . 17 83 9.3. MPL Data Message Processing . . . . . . . . . . . . . . . 18 84 10. MPL Control Messages . . . . . . . . . . . . . . . . . . . . 19 85 10.1. MPL Control Message Generation . . . . . . . . . . . . . 19 86 10.2. MPL Control Message Transmission . . . . . . . . . . . . 20 87 10.3. MPL Control Message Processing . . . . . . . . . . . . . 20 88 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 21 89 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22 90 12.1. MPL Option Type . . . . . . . . . . . . . . . . . . . . 22 91 12.2. MPL ICMPv6 Type . . . . . . . . . . . . . . . . . . . . 22 92 12.3. Well-known Multicast Addresses . . . . . . . . . . . . . 23 93 13. Security Considerations . . . . . . . . . . . . . . . . . . . 23 94 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 23 95 14.1. Normative References . . . . . . . . . . . . . . . . . . 23 96 14.2. Informative References . . . . . . . . . . . . . . . . . 24 98 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25 100 1. Introduction 102 Low power and Lossy Networks typically operate with strict resource 103 constraints in communication, computation, memory, and energy. Such 104 resource constraints may preclude the use of existing IPv6 multicast 105 routing and forwarding mechanisms. Traditional IP multicast delivery 106 typically relies on topology maintenance mechanisms to discover and 107 maintain routes to all subscribers of a multicast group (e.g. 108 [RFC3973] [RFC4601]). However, maintaining such topologies in LLNs 109 is costly and may not be feasible given the available resources. 111 Memory constraints may limit devices to maintaining links/routes to 112 one or a few neighbors. For this reason, the Routing Protocol for 113 LLNs (RPL) specifies both storing and non-storing modes [RFC6550]. 114 The latter allows RPL routers to maintain only one or a few default 115 routes towards a LLN Border Router (LBR) and use source routing to 116 forward messages away from the LBR. For the same reasons, a LLN 117 device may not be able to maintain a multicast routing topology when 118 operating with limited memory. 120 Furthermore, the dynamic properties of wireless networks can make the 121 cost of maintaining a multicast routing topology prohibitively 122 expensive. In wireless environments, topology maintenance may 123 involve selecting a connected dominating set used to forward 124 multicast messages to all nodes in an administrative domain. 125 However, existing mechanisms often require two-hop topology 126 information and the cost of maintaining such information grows 127 polynomially with network density. 129 This document specifies the Multicast Protocol for Low power and 130 Lossy Networks (MPL), which provides IPv6 multicast forwarding in 131 constrained networks. MPL avoids the need to construct or maintain 132 any multicast routing topology, disseminating multicast messages to 133 all MPL Forwarders in an MPL Domain. By using the Trickle algorithm 134 [RFC6206], MPL requires only small, constant state for each MPL 135 device that initiates disseminations. The Trickle algorithm also 136 allows MPL to be density-aware, allowing the communication rate to 137 scale logarithmically with density. 139 2. Terminology 141 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 142 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 143 "OPTIONAL" in this document are to be interpreted as described in 144 [RFC2119]. 146 The following terms are used throughout this document: 148 MPL Forwarder - A router that implements this protocol. An MPL 149 Forwarder is equipped with at least one MPL 150 Interface. 152 MPL Interface - An MPL Forwarder's attachment to a 153 communications medium, over which it transmits 154 and receives MPL Data Messages and MPL Control 155 Messages according to this specification. An MPL 156 Interface is assigned one or more unicast 157 addresses and is subscribed to one or more MPL 158 Domain Addresses. 160 MPL Domain Address - A multicast address that identifies the set of 161 MPL Interfaces within an MPL Domain. MPL Data 162 Messages disseminated in an MPL Domain have the 163 associated MPL Domain Address as their 164 destination address. 166 MPL Domain - A scope zone, as defined in [RFC4007], in which 167 MPL Interfaces subscribe to the same MPL Domain 168 Address and participate in disseminating MPL Data 169 Messages. 171 MPL Data Message - A multicast message that is used to communicate 172 a multicast payload between MPL Forwarders within 173 an MPL domain. An MPL Data Message contains an 174 MPL Option in the IPv6 header and has as its 175 destination address the MPL Domain Address 176 corresponding to the MPL Domain. 178 MPL Control Message - A link-local multicast message that is used to 179 communicate information about recently received 180 MPL Data Messages to neighboring MPL Forwarders. 182 MPL Seed - An MPL Forwarder that generates MPL Data 183 Messages and serves as an entry point into an MPL 184 Domain. 186 MPL Seed Identifier - An unsigned integer that uniquely identifies an 187 MPL Seed within an MPL Domain. 189 3. Applicability Statement 191 This protocol is an IPv6 multicast forwarding protocol designed for 192 the communication characteristics and resource constraints of Low- 193 Power and Lossy Networks. By implementing controlled disseminations 194 of multicast messages using the Trickle algorithm, this protocol is 195 designed for networks that communicate using low-power and lossy 196 links with widely varying topologies in both the space and time 197 dimensions. 199 While designed specifically for Low-Power and Lossy Networks, this 200 protocol is not limited to use over such networks. This protocol may 201 be applicable to any network where no multicast routing state is 202 desired. This protocol may also be used in environments where only a 203 subset of links are considered Low-Power and Lossy links. 205 Operationally, the scope of this protocol is administratively 206 determined. In other words, the scope of dissemination is determined 207 by routers configured to disallow transmission or reception of MPL 208 messages on a subset of interfaces. 210 A host need not be aware that their multicast is supported by MPL as 211 long as its attachment router forwards multicast messages between the 212 MPL Domain and the host. However, a host may choose to implement MPL 213 so that it can take advantage of the broadcast medium inherent in 214 many Low-Power and Lossy Networks and receive multicast messages 215 carried by MPL directly. 217 4. Protocol Overview 219 The goal of MPL is to deliver multicast messages to all interfaces 220 that subscribe to the multicast messages' destination address within 221 an MPL Domain. 223 4.1. MPL Domains 225 An MPL Domain is a scope zone, as defined in [RFC4007], in which MPL 226 Interfaces subscribe to the same MPL Domain Address and participate 227 in disseminating MPL Data Messages. 229 By default, an MPL Forwarder SHOULD participate in an MPL Domain 230 identified by the ALL_MPL_FORWARDERS multicast address with a scope 231 value of 3 (Realm-Local) [I-D.droms-6man-multicast-scopes]. When 232 used with MPL, Realm-Local scope is administratively defined and used 233 to define the boundaries of multicast message dissemination by MPL. 235 An MPL Forwarder MAY participate in additional MPL Domains identified 236 by other multicast addresses. An MPL Interface MUST subscribe to the 237 MPL Domain Addresses for the MPL Domains that it participates in. 238 The assignment of other multicast addresses is out of scope. 240 For each MPL Domain Address that an MPL Interface subscribes to, the 241 MPL Interface MUST also subscribe to the same MPL Domain Address with 242 a scope value of 2 (link-local) when reactive forwarding is in use 243 (i.e. when communicating MPL Control Messages). 245 4.2. Information Base Overview 247 A node records necessary protocol state in the following information 248 sets: 250 o The Local Interface Set records the set of local MPL Interfaces 251 and the unicast addresses assigned to those MPL Interfaces. 253 o The Domain Set records the set of MPL Domain Addresses and the 254 local MPL Interfaces that subscribe to those addresses. 256 o A Seed Set records information about received MPL Data Messages 257 received from an MPL Seed within an MPL Domain. Each MPL Domain 258 has an associated Seed Set. A Seed Set maintains the minimum 259 sequence number for MPL Data Messages that the MPL Forwarder is 260 willing to receive or has buffered in its Buffered Message Set 261 from an MPL Seed. MPL uses Seed Sets and Buffered Message Sets to 262 determine when to accept an MPL Data Message, process its payload, 263 and retransmit it. 265 o A Buffered Message Set records recently received MPL Data Messages 266 from an MPL Seed within an MPL Domain. Each MPL Domain has an 267 associated Buffered Message Set. MPL Data Messages resident in a 268 Buffered Message Set have sequence numbers that are greater than 269 or equal to the minimum threshold maintained in the corresponding 270 Seed Set. MPL uses Buffered Message Sets to store MPL Data 271 Messages that may be transmitted by the MPL Forwarder for 272 forwarding. 274 4.3. Overview 276 MPL achieves its goal by implementing a controlled flood that 277 attempts to disseminate the multicast data message to all interfaces 278 within an MPL Domain. MPL performs the following tasks to 279 disseminate a multicast message: 281 o When having a multicast message to forward into an MPL Domain, the 282 MPL Seed generates an MPL Data Message that includes the MPL 283 Domain Address as the IPv6 Destination Address, the MPL Seed 284 Identifier, a newly generated sequence number, and the multicast 285 message. If the multicast destination address is not the MPL 286 Domain Address, IP-in-IP [RFC2473] is used to encapsulate the 287 multicast message in an MPL Data Message, preserving the original 288 IPv6 Destination Address. 290 o Upon receiving an MPL Data Message, the MPL Forwarder extracts the 291 MPL Seed and sequence number and determines whether or not the MPL 292 Data Message was previously received using the MPL Domain's Seed 293 Set and Buffered Message Set. 295 * If the sequence number is less than the lower-bound sequence 296 number maintained in the Seed Set or a message with the same 297 sequence number exists within the Buffered Message Set, the MPL 298 Forwarder marks the MPL Data Message as old. 300 * Otherwise, the MPL Forwarder marks the MPL Data Message as new. 302 o For each newly received MPL Data Message, an MPL Forwarder updates 303 the Seed Set, adds the MPL Data Message into the Buffered Message 304 Set, processes its payload, and multicasts the MPL Data Message a 305 number of times on all MPL Interfaces participating in the same 306 MPL Domain to forward the message. 308 o Each MPL Forwarder may periodically link-local multicast MPL 309 Control Messages on MPL Interfaces to communicate information 310 contained in an MPL Domain's Seed Set and Buffered Message Set. 312 o Upon receiving an MPL Control Message, an MPL Forwarder determines 313 whether there are any new MPL Data Messages that have yet to be 314 received by the MPL Control Message's source and multicasts those 315 MPL Data Messages. 317 MPL's configuration parameters allow two forwarding strategies for 318 disseminating MPL Data Messages. 320 Proactive Forwarding - With proactive forwarding, an MPL Forwarder 321 schedules transmissions of MPL Data Messages using the Trickle 322 algorithm, without any prior indication that neighboring nodes 323 have yet to receive the message. After transmitting the MPL Data 324 Message a limited number of times, the MPL Forwarder may terminate 325 proactive forwarding for the MPL Data Message message. 327 Reactive Forwarding - With reactive forwarding, an MPL Forwarder 328 link-local multicasts MPL Control Messages using the Trickle 329 algorithm [RFC6206]. MPL Forwarders use MPL Control Messages to 330 discover new MPL Data Messages that have not yet been received. 331 When discovering that a neighboring MPL Forwarder has not yet 332 received an MPL Data Message, the MPL Forwarder schedules those 333 MPL Data Messages for transmission using the Trickle algorithm. 335 Note that the use of proactive and reactive forwarding strategies 336 within the same MPL Domain are not mutually exclusive and may be used 337 simultaneously. For example, upon receiving a new MPL Data messages 338 when both proactive and reactive forwarding techniques are enabled, 339 an MPL Forwarder will proactively retransmit the MPL Data Message a 340 limited number of times and schedule further transmissions upon 341 receiving MPL Control Messages. 343 4.4. Signaling Overview 345 This protocol generates and processes the following messages: 347 MPL Data Message - Generated by an MPL Seed to deliver a multicast 348 message across an MPL Domain. The MPL Data Message's source is an 349 address in the Local Interface Set of the MPL Seed that generated 350 the message and is valid within the MPL Domain. The MPL Data 351 Message's destination is the MPL Domain Address corresponding to 352 the MPL Domain. An MPL Data Message contains: 354 * The Seed Identifier of the MPL Seed that generated the MPL Data 355 Message. 357 * The sequence number of the MPL Seed that generated the MPL Data 358 Message. 360 * The original multicast message. 362 MPL Control Message - Generated by an MPL Forwarder to communicate 363 information contained in an MPL Domain's Seed Set and Buffered 364 Message Set to neighboring MPL Forwarders. An MPL Control Message 365 contains a list of tuples for each entry in the Seed Set. Each 366 tuple contains: 368 * The minimum sequence number maintained in the Seed Set for the 369 MPL Seed. 371 * A bit-vector indicating the sequence numbers of MPL Data 372 Messages resident in the Buffered Message Set for the MPL Seed, 373 where the first bit represents a sequence number equal to the 374 minimum threshold maintained in the Seed Set. 376 * The length of the bit-vector. 378 5. MPL Parameters and Constants 380 This section describes various program and networking parameters and 381 constants used by MPL. 383 5.1. MPL Multicast Addresses 385 MPL makes use of MPL Domain Addresses to identify MPL Interfaces of 386 an MPL Domain. By default, MPL Forwarders subscribe to the 387 ALL_MPL_FORWARDERS multicast address with a scope value of 3 388 [I-D.droms-6man-multicast-scopes]. 390 For each MPL Domain Address that an MPL Interface subscribes to, the 391 MPL Interface MUST also subscribe to the MPL Domain Address with a 392 scope value of 2 (link-local) when reactive forwarding is in use. 393 MPL Forwarders use the link-scoped MPL Domain Address to communicate 394 MPL Control Messages to neighboring (i.e. on-link) MPL Forwarders. 396 5.2. MPL Message Types 398 MPL defines an IPv6 Option for carrying an MPL Seed Identifier and a 399 sequence number within an MPL Data Message. The IPv6 Option Type has 400 value MPL_OPT_TYPE. 402 MPL defines an ICMPv6 Message (MPL Control Message) for communicating 403 information contained in an MPL Domain's Seed Set and Buffered 404 Message Set to neighboring MPL Forwarders. The MPL Control Message 405 has ICMPv6 Type MPL_ICMP_TYPE. 407 5.3. MPL Seed Identifiers 409 MPL uses MPL Seed Identifiers to uniquely identify MPL Seeds within 410 an MPL Domain. For each MPL Domain that the MPL Forwarder serves as 411 an MPL Seed, the MPL Forwarder MUST have an associated MPL Seed 412 Identifier. An MPL Forwarder MAY use the same MPL Seed Identifier 413 across multiple MPL Domains, but the MPL Seed Identifier MUST be 414 unique within each MPL Domain. The mechanism for assigning and 415 verifying uniqueness of MPL Seed Identifiers is not specified in this 416 document. 418 5.4. MPL Forwarder Parameters 420 PROACTIVE_FORWARDING A boolean value that indicates whether the MPL 421 Forwarder should schedule MPL Data Message transmissions after 422 receiving them for the first time. PROACTIVE_FORWARDING has a 423 default value of TRUE. 425 SEED_SET_ENTRY_LIFETIME The minimum lifetime for an entry in the 426 Seed Set. SEED_SET_ENTRY_LIFETIME has a default value of 30 427 minutes. 429 It is RECOMMENDED that all MPL Forwarders use the same values for the 430 MPL Forwarder Parameters above for a given MPL Domain. The mechanism 431 for setting the MPL Forwarder Parameters is not specified within this 432 document. 434 5.5. MPL Trickle Parameters 436 As specified in [RFC6206], a Trickle timer runs for a defined 437 interval and has three configuration parameters: the minimum interval 438 size Imin, the maximum interval size Imax, and a redundancy constant 439 k. 441 This specification defines a fourth Trickle configuration parameter, 442 TimerExpirations, which indicates the number of Trickle timer 443 expiration events that occur before terminating the Trickle algorithm 444 for a given MPL Data Message or MPL Control Message. 446 Each MPL Forwarder uses the following Trickle parameters for MPL Data 447 Message and MPL Control Message transmissions. 449 DATA_MESSAGE_IMIN The minimum Trickle timer interval, as defined in 450 [RFC6206], for MPL Data Message transmissions. DATA_MESSAGE_IMIN 451 has a default value of 10 times the expected link-layer latency. 453 DATA MESSAGE_IMAX The maximum Trickle timer interval, as defined in 454 [RFC6206], for MPL Data Message transmissions. DATA_MESSAGE_IMAX 455 has a default value equal to DATA_MESSAGE_IMIN. 457 DATA_MESSAGE_K The redundancy constant, as defined in [RFC6206], for 458 MPL Data Message transmissions. DATA_MESSAGE_K has a default 459 value of 1. 461 DATA_MESSAGE_TIMER_EXPIRATIONS The number of Trickle timer 462 expirations that occur before terminating the Trickle algorithm's 463 retransmission of a given MPL Data Message. 464 DATA_MESSAGE_TIMER_EXPIRATIONS has a default value of 3. 466 CONTROL_MESSAGE_IMIN The minimum Trickle timer interval, as defined 467 in [RFC6206], for MPL Control Message transmissions. 468 CONTROL_MESSAGE_IMIN has a default value of 10 times the worst- 469 case link-layer latency. 471 CONTROL_MESSAGE_IMAX The maximum Trickle timer interval, as defined 472 in [RFC6206], for MPL Control Message transmissions. 473 CONTROL_MESSAGE_IMAX has a default value of 5 minutes. 475 CONTROL_MESSAGE_K The redundancy constant, as defined in [RFC6206], 476 for MPL Control Message transmissions. CONTROL_MESSAGE_K has a 477 default value of 1. 479 CONTROL_MESSAGE_TIMER_EXPIRATIONS The number of Trickle timer 480 expirations that occur before terminating the Trickle algorithm 481 for MPL Control Message transmissions. 482 CONTROL_MESSAGE_TIMER_EXPIRATIONS has a default value of 10. 484 Following [RFC6206], it is RECOMMENDED that all MPL Forwarders use 485 the same values for the Trickle Parameters above for a given MPL 486 Domain. The mechanism for setting the Trickle Parameters is not 487 specified within this document. 489 The default Trickle parameter values above combined with the default 490 MPL Forwarder parameters in the prior section specify a forwarding 491 strategy that utilizes both proactive and reactive techniques. Using 492 these default values, an MPL Forwarder proactively transmits any new 493 MPL Data Messages it receives then uses MPL Control Messages to 494 trigger additional MPL Data Message retransmissions where message 495 drops are detected. Setting DATA_MESSAGE_IMAX to the same as 496 DATA_MESSAGE_IMIN in this case is acceptable since subsequent MPL 497 Data Message retransmissions are triggered by MPL Control Messages, 498 where CONTROL_MESSAGE_IMAX is greater than CONTROL_MESSAGE_IMIN. 500 6. Protocol Message Formats 502 The protocol messages generated and processed by an MPL Forwarder are 503 described in this section. 505 6.1. MPL Option 507 The MPL Option is carried in MPL Data Messages in an IPv6 Hop-by-Hop 508 Options header, immediately following the IPv6 header. The MPL 509 Option has the following format: 511 0 1 2 3 512 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 513 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 514 | Option Type | Opt Data Len | 515 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 516 | S |M|V| rsv | sequence | seed-id (optional) | 517 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 519 Option Type MPL_OPT_TYPE 521 Opt Data Len Length of the Option Data field in octets. 523 S 2-bit unsigned integer. Identifies the length of 524 seed-id. 0 indicates that the seed-id is the 525 IPv6 Source Address and not included in the MPL 526 Option. 1 indicates that the seed-id is a 16-bit 527 unsigned integer. 2 indicates that the seed-id 528 is a 64-bit unsigned integer. 3 indicates that 529 the seed-id is a 128-bit unsigned integer. 531 M 1-bit flag. 1 indicates that the value in 532 sequence is known to be the largest sequence 533 number that was received from the MPL Seed. 535 V 1-bit flag. 0 indicates that the MPL Option 536 conforms to this specification. MPL Data 537 Messages with an MPL Option in which this flag is 538 1 MUST be dropped. 540 rsv 4-bit reserved field. MUST be set to 0 on 541 transmission and ignored on reception. 543 sequence 8-bit unsigned integer. Identifies relative 544 ordering of MPL Data Messages from the MPL Seed 545 identified by seed-id. 547 seed-id Uniquely identifies the MPL Seed that initiated 548 dissemination of the MPL Data Message. The size 549 of seed-id is indicated by the S field. 551 The Option Data (in particular the M flag) of the MPL Option is 552 updated by MPL Forwarders as the MPL Data Message is forwarded. 553 Nodes that do not understand the MPL Option MUST discard the MPL Data 554 Message. Thus, according to [RFC2460] the three high order bits of 555 the Option Type are set to '011'. The Option Data length is 556 variable. 558 The seed-id uniquely identifies an MPL Seed. When seed-id is 128 559 bits (S=3), the MPL seed MAY use an IPv6 address assigned to one of 560 its interfaces that is unique within the MPL Domain. Managing MPL 561 Seed Identifiers is not within scope of this document. 563 The sequence field establishes a total ordering of MPL Data Messages 564 generated by an MPL Seed for an MPL Domain. The MPL Seed MUST 565 increment the sequence field's value on each new MPL Data Message 566 that it generates for an MPL Domain. Implementations MUST follow the 567 Serial Number Arithmetic as defined in [RFC1982] when incrementing a 568 sequence value or comparing two sequence values. 570 Future updates to this specification may define additional fields 571 following the seed-id field. 573 6.2. MPL Control Message 575 An MPL Forwarder uses ICMPv6 messages to communicate information 576 contained in an MPL Domain's Seed Set and Buffered Message Set to 577 neighboring MPL Forwarders. The MPL Control Message has the 578 following format: 580 0 1 2 3 581 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 582 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 583 | Type | Code | Checksum | 584 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 585 | | 586 . MPL Seed Info[0..n] . 587 . . 588 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 590 IP Fields: 592 Source Address An IPv6 address in the AddressSet of the 593 corresponding MPL Interface and MUST be valid 594 within the MPL Domain. 596 Destination Address The link-scoped MPL Domain Address corresponding 597 to the MPL Domain. 599 Hop Limit 255 601 ICMPv6 Fields: 603 Type MPL_ICMP_TYPE 604 Code 0 606 Checksum The ICMP checksum. See [RFC4443]. 608 MPL Seed Info[0..n] List of zero or more MPL Seed Info entries. 610 The MPL Control Message indicates the sequence numbers of MPL Data 611 Messages that are within the MPL Domain's Buffered Message Set. The 612 MPL Control Message also indicates the sequence numbers of MPL Data 613 Messages that an MPL Forwarder is willing to receive. The MPL 614 Control Message allows neighboring MPL Forwarders to determine 615 whether there are any new MPL Data Messages to exchange. 617 6.3. MPL Seed Info 619 An MPL Seed Info encodes the minimum sequence number for an MPL Seed 620 maintained in the MPL Domain's Seed Set. The MPL Seed Info also 621 indicates the sequence numbers of MPL Data Messages generated by the 622 MPL Seed that are stored within the MPL Domain's Buffered Message 623 Set. The MPL Seed Info has the following format: 625 0 1 2 3 626 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 627 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 628 | min-seqno | bm-len | S | seed-id (0/2/8/16 octets) | 629 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 630 | | 631 . buffered-mpl-messages (variable length) . 632 . . 633 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 635 min-seqno 8-bit unsigned integer. The lower-bound sequence 636 number for the MPL Seed. 638 bm-len 6-bit unsigned integer. The size of buffered- 639 mpl-messages in octets. 641 S 2-bit unsigned integer. Identifies the length of 642 seed-id. 0 indicates that the seed-id value is 643 the IPv6 Source Address and not included in the 644 MPL Seed Info. 1 indicates that the seed-id 645 value is a 16-bit unsigned integer. 2 indicates 646 that the seed-id value is a 64-bit unsigned 647 integer. 3 indicates that the seed-id is a 648 128-bit unsigned integer. 650 seed-id Variable-length unsigned integer. Indicates the 651 MPL Seed associated with this MPL Seed Info. 653 buffered-mpl-messages Variable-length bit vector. Identifies the 654 sequence numbers of MPL Data Messages maintained 655 in the corresponding Buffered Message Set for the 656 MPL Seed. The i'th bit represents a sequence 657 number of min-seqno + i. '0' indicates that the 658 corresponding MPL Data Message does not exist in 659 the Buffered Message Set. '1' indicates that the 660 corresponding MPL Data Message does exist in the 661 Buffered Message Set. 663 The MPL Seed Info does not have any octet alignment requirement. 665 7. Information Base 667 7.1. Local Interface Set 669 The Local Interface Set records the local MPL Interfaces of an MPL 670 Forwarder. The Local Interface Set consists of Local Interface 671 Tuples, one per MPL Interface: (AddressSet). 673 AddressSet - a set of unicast addresses assigned to the MPL 674 Interface. 676 7.2. Domain Set 678 The Domain Set records the MPL Interfaces that subscribe to each MPL 679 Domain Address. The Domain Set consists of MPL Domain Tuples, one 680 per MPL Domain: (MPLInterfaceSet). 682 MPLInterfaceSet - a set of MPL Interfaces that subscribe to the MPL 683 Domain Address that identifies the MPL Domain. 685 7.3. Seed Set 687 A Seed Set records a sliding window used to determine the sequence 688 numbers of MPL Data Messages that an MPL Forwarder is willing to 689 accept generated by the MPL Seed. An MPL Forwarder maintains a Seed 690 Set for each MPL Domain that it participates in. A Seed Set consists 691 of MPL Seed Tuples: (SeedID, MinSequence, Lifetime). 693 SeedID - the identifier for the MPL Seed. 695 MinSequence - a lower-bound sequence number that represents the 696 sequence number of the oldest MPL Data Message the MPL Forwarder 697 is willing to receive or transmit. An MPL Forwarder MUST ignore 698 any MPL Data Message that has sequence value less than than 699 MinSequence. 701 Lifetime - indicates the minimum remaining lifetime of the Seed Set 702 entry. An MPL Forwarder MUST NOT free a Seed Set entry before the 703 remaining lifetime expires. 705 7.4. Buffered Message Set 707 A Buffered Message Set records recently received MPL Data Messages 708 from an MPL Seed within an MPL Domain. An MPL Forwarder uses a 709 Buffered Message Set to buffer MPL Data Messages while the MPL 710 Forwarder is forwarding the MPL Data Messages. An MPL Forwarder 711 maintains a Buffered Message Set for each MPL Domain that it 712 participates in. A Buffered Message Set consists of Buffered Message 713 Tuples: (SeedID, SequenceNumber, DataMessage). 715 SeedID - the identifier for the MPL Seed that generated the MPL Data 716 Message. 718 SequenceNumber - the sequence number for the MPL Data Message. 720 DataMessage - the MPL Data Message. 722 All MPL Data Messages within a Buffered Message Set MUST have a 723 sequence number greater than or equal to MinSequence for the 724 corresponding SeedID. When increasing MinSequence for an MPL Seed, 725 the MPL Forwarder MUST delete any MPL Data Messages from the 726 corresponding Buffered Message Set that have sequence numbers less 727 than MinSequence. 729 8. MPL Seed Sequence Numbers 731 Each MPL Seed maintains a sequence number for each MPL Domain that it 732 serves. The sequence numbers are included in MPL Data Messages 733 generated by the MPL Seed. The MPL Seed MUST increment the sequence 734 number for each MPL Data Message that it generates for an MPL Domain. 735 Implementations MUST follow the Serial Number Arithmetic as defined 736 in [RFC1982] when incrementing a sequence value or comparing two 737 sequence values. This sequence number is used to establish a total 738 ordering of MPL Data Messages generated by an MPL Seed for an MPL 739 Domain. 741 9. MPL Data Messages 743 9.1. MPL Data Message Generation 745 MPL Data Messages are generated by MPL Seeds when these messages 746 enter the MPL Domain. All MPL Data messages have the following 747 properties: 749 o The IPv6 Source Address MUST be an address in the AddressSet of a 750 corresponding MPL Interface and MUST be valid within the MPL 751 Domain. 753 o The IPv6 Destination Address MUST be set to the MPL Domain Address 754 corresponding to the MPL Domain. 756 o An MPL Data Message MUST contain an MPL Option in its IPv6 Header 757 to identify the MPL Seed that generated the message and the 758 ordering relative to other MPL Data Messages generated by the MPL 759 Seed. 761 When the destination address is an MPL Domain Address and the source 762 address is in the AddressLIst of an MPL Interface that belongs to 763 that MPL Domain Address, the application message and the MPL Data 764 Message MAY be identical. In other words, the MPL Data Message may 765 contain a single IPv6 header that includes the MPL Option. 767 Otherwise, IPv6-in-IPv6 encapsulation MUST be used to satisfy the MPL 768 Data Message requirements listed above [RFC2473]. The complete IPv6 769 -in-IPv6 message forms an MPL Data Message. The outer IPv6 header 770 conforms to the MPL Data Message requirements listed above. The 771 encapsulated IPv6 datagram encodes the multicast data message that is 772 communicated beyond the MPL Domain. 774 9.2. MPL Data Message Transmission 776 An MPL Forwarder manages transmission of MPL Data Messages in its 777 Buffered Message Sets using the Trickle algorithm [RFC6206]. An MPL 778 Forwarder MUST use a separate Trickle timer for each MPL Data Message 779 that it is actively forwarding. In accordance with Section 5 of RFC 780 6206 [RFC6206], this document defines the following: 782 o This document defines a "consistent" transmission as receiving an 783 MPL Data Message that has the same MPL Domain Address, seed-id, 784 and sequence value as the MPL Data Message managed by the Trickle 785 timer. 787 o This document defines an "inconsistent" transmission as receiving 788 an MPL Data Message that has the same MPL Domain Address, seed-id 789 value, and the M flag set, but has a sequence value less than MPL 790 Data Message managed by the Trickle timer. 792 o This document does not define any external "events". 794 o This document defines MPL Data Messages as Trickle messages. 796 o The actions outside the Trickle algorithm that the protocol takes 797 involve managing the MPL Domain's Seed Set and Buffered Message 798 Set. 800 As specified in [RFC6206], a Trickle timer has three variables: the 801 current interval size I, a time within the current interval t, and a 802 counter c. MPL defines a fourth variable, e, which counts the number 803 of Trickle timer expiration events since the Trickle timer was last 804 reset. 806 After DATA_MESSAGE_TIMER_EXPIRATIONS Trickle timer events, the MPL 807 Forwarder MUST disable the Trickle timer. When a buffered MPL Data 808 Message does not have an associated Trickle timer, the MPL Forwarder 809 MAY delete the message from the Buffered Message Set by advancing 810 MinSequence of the corresponding MPL Seed in the Seed Set. When the 811 MPL Forwarder no longer buffers any messages for an MPL Seed, the MPL 812 Forwarder MUST NOT increment MinSequence for that MPL Seed. 814 When transmitting an MPL Data Message, the MPL Forwarder MUST either 815 set the M flag to zero or set it to a level that indicates whether or 816 not the message's sequence number is the largest value that has been 817 received from the MPL Seed. 819 9.3. MPL Data Message Processing 821 Upon receiving an MPL Data Message, the MPL Forwarder first processes 822 the MPL Option and updates the Trickle timer associated with the MPL 823 Data Message if one exists. 825 Upon receiving an MPL Data Message, an MPL Forwarder MUST perform one 826 of the following actions: 828 o Accept the message and enter the MPL Data Message in the MPL 829 Domain's Buffered Message Set. 831 o Accept the message and update the corresponding MinSequence in the 832 MPL Domain's Seed Set to 1 greater than the message's sequence 833 number. 835 o Discard the message without any change to the MPL Information 836 Base. 838 If a Seed Set entry exists for the MPL Seed, the MPL Forwarder MUST 839 discard the MPL Data Message if its sequence number is less than 840 MinSequence or exists in the Buffered Message Set. 842 If a Seed Set entry does not exist for the MPL Seed, the MPL 843 Forwarder MUST create a new entry for the MPL Seed before accepting 844 the MPL Data Message. 846 If memory is limited, an MPL Forwarder SHOULD reclaim memory 847 resources by: 849 o Incrementing MinSequence entries in a Seed Set and deleting MPL 850 Data Messages in the corresponding Buffered Message Set that fall 851 below the MinSequence value. 853 o Deleting other Seed Set entries that have expired and the 854 corresponding MPL Data Messages in the Buffered Message Set. 856 If the MPL Forwarder accepts the MPL Data Message, the MPL Forwarder 857 MUST perform the following actions: 859 o Reset the Lifetime of the corresponding Seed Set entry to 860 SEED_SET_ENTRY_LIFETIME. 862 o If PROACTIVE_FORWARDING is true, the MPL Forwarder MUST initialize 863 and start a Trickle timer for the MPL Data Message. 865 o If the MPL Control Message Trickle timer is not running and 866 CONTROL_MESSAGE_TIMER_EXPIRATIONS is non-zero, the MPL Forwarder 867 MUST initialize and start the MPL Control Message Trickle timer. 869 o If the MPL Control Message Trickle timer is running, the MPL 870 Forwarder MUST reset the MPL Control Message Trickle timer. 872 10. MPL Control Messages 874 10.1. MPL Control Message Generation 876 An MPL Forwarder generates MPL Control Messages to communicate an MPL 877 Domain's Seed Set and Buffered Message Set to neighboring MPL 878 Forwarders. Each MPL Control Message is generated according to 879 Section 6.2, with an MPL Seed Info for each entry in the MPL Domain's 880 Seed Set. Each MPL Seed Info entry has the following content: 882 o S set to the size of the seed-id field in the MPL Seed Info entry. 884 o min-seqno set to MinSequence of the MPL Seed. 886 o bm-len set to the size of buffered-mpl-messages in octets. 888 o seed-id set to the MPL seed identifier. 890 o buffered-mpl-messages with each bit representing whether or not an 891 MPL Data Message with the corresponding sequence number exists in 892 the Buffered Message Set. The i'th bit represents a sequence 893 number of min-seqno + i. '0' indicates that the corresponding MPL 894 Data Message does not exist in the Buffered Message Set. '1' 895 indicates that the corresponding MPL Data Message does exist in 896 the Buffered Message Set. 898 10.2. MPL Control Message Transmission 900 An MPL Forwarder transmits MPL Control Messages using the Trickle 901 algorithm. An MPL Forwarder maintains a single Trickle timer for 902 each MPL Domain. When CONTROL_MESSAGE_TIMER_EXPIRATIONS is 0, the 903 MPL Forwarder does not execute the Trickle algorithm and does not 904 transmit MPL Control Messages. In accordance with Section 5 of RFC 905 6206 [RFC6206], this document defines the following: 907 o This document defines a "consistent" transmission as receiving an 908 MPL Control Message that results in a determination that neither 909 the receiving nor transmitting node has any new MPL Data Messages 910 to offer. 912 o This document defines an "inconsistent" transmission as receiving 913 an MPL Control Message that results in a determination that either 914 the receiving or transmitting node has at least one new MPL Data 915 Message to offer. 917 o The Trickle timer is reset in response to external "events." This 918 document defines an "event" as increasing MinSequence of any entry 919 in the corresponding Seed Set or adding a message to the 920 corresponding Buffered Message Set. 922 o This document defines an MPL Control Message as a Trickle message. 924 As specified in [RFC6206], a Trickle timer has three variables: the 925 current interval size I, a time within the current interval t, and a 926 counter c. MPL defines a fourth variable, e, which counts the number 927 of Trickle timer expiration events since the Trickle timer was last 928 reset. After CONTROL_MESSAGE_TIMER_EXPIRATIONS Trickle timer events, 929 the MPL Forwarder MUST disable the Trickle timer. 931 10.3. MPL Control Message Processing 932 An MPL Forwarder processes each MPL Control Message that it receives 933 to determine if it has any new MPL Data Messages to receive or offer. 935 An MPL Forwarder determines if a new MPL Data Message has not been 936 received from a neighboring node if any of the following conditions 937 hold true: 939 o The MPL Control Message includes an MPL Seed that does not exist 940 in the MPL Domain's Seed Set. 942 o The MPL Control Message indicates that the neighbor has an MPL 943 Data Message in its Buffered Message Set with sequence number 944 greater than MinSequence (i.e. the i-th bit is set to 1 and min- 945 seqno + i > MinSequence) and is not included in the MPL Domain's 946 Buffered Message Set. 948 When an MPL Forwarder determines that it has not yet received an MPL 949 Data Message buffered by a neighboring device, the MPL Forwarder MUST 950 reset its Trickle timer associated with MPL Control Message 951 transmissions. If an MPL Control Message Trickle timer is not 952 running, the MPL Forwarder MUST initialize and start a new Trickle 953 timer. 955 An MPL Forwarder determines if an MPL Data Message in the Buffered 956 Message Set has not yet been received by a neighboring MPL Forwarder 957 if any of the following conditions hold true: 959 o The MPL Control Message does not include an MPL Seed for the MPL 960 Data Message. 962 o The MPL Data Message's sequence number is greater than or equal to 963 min-seqno and not included in the neighbor's corresponding 964 Buffered Message Set (i.e. the MPL Data Message's sequence number 965 does not have a corresponding bit in buffered-mpl-messages set to 966 1). 968 When an MPL Forwarder determines that it has at least one MPL Data 969 Message in its corresponding Buffered Message Set that has not yet 970 been received by a neighbor, the MPL Forwarder MUST reset the MPL 971 Control Message Trickle timer. Additionally, for each of those 972 entries in the Buffered Message Set, the MPL Forwarder MUST reset the 973 Trickle timer and reset e to 0. If a Trickle timer is not associated 974 with the MPL Data Message, the MPL Forwarder MUST initialize and 975 start a new Trickle timer. 977 11. Acknowledgements 978 The authors would like to acknowledge the helpful comments of Robert 979 Cragie, Esko Dijk, Ralph Droms, Paul Duffy, Adrian Farrel, Ulrich 980 Herberg, Owen Kirby, Kerry Lynn, Joseph Reddy, Michael Richardson, 981 Don Sturek, Dario Tedeschi, and Peter van der Stok, which greatly 982 improved the document. 984 12. IANA Considerations 986 This document defines one IPv6 Option, a type that must be allocated 987 from the IPv6 "Destination Options and Hop-by-Hop Options" registry 988 of [RFC2780]. 990 This document defines one ICMPv6 Message, a type that must be 991 allocated from the "ICMPv6 "type" Numbers" registry of [RFC4443]. 993 This document registers two well-known multicast addresses from the 994 IPv6 multicast address space. 996 12.1. MPL Option Type 998 IANA is requested to allocate an IPv6 Option Type from the IPv6 999 "Destination Options and Hop-by-Hop Options" registry of [RFC2780], 1000 as specified in Table 1 below: 1002 +--------------+-------+-----+------------+-------------+-----------+ 1003 | Mnemonic | act | chg | rest | Description | Reference | 1004 +--------------+-------+-----+------------+-------------+-----------+ 1005 | MPL_OPT_TYPE | 01 | 1 | TBD | MPL Option | This | 1006 | | | | (suggested | | Document | 1007 | | | | value | | | 1008 | | | | 01101) | | | 1009 +--------------+-------+-----+------------+-------------+-----------+ 1011 Table 1: IPv6 Option Type Allocation 1013 12.2. MPL ICMPv6 Type 1015 IANA is requested to allocate an ICMPv6 Type from the "ICMPv6 "type" 1016 Numbers" registry of [RFC4443], as specified in Table 2 below: 1018 +---------------+------+---------------------+---------------+ 1019 | Mnemonic | Type | Name | Reference | 1020 +---------------+------+---------------------+---------------+ 1021 | MPL_ICMP_TYPE | TBD | MPL Control Message | This Document | 1022 +---------------+------+---------------------+---------------+ 1024 Table 2: IPv6 Option Type Allocation 1026 12.3. Well-known Multicast Addresses 1028 IANA is requested to allocate an IPv6 multicast address, with Group 1029 ID in the range [0x01,0xFF] for 6LoWPAN compression [RFC6282], 1030 "ALL_MPL_FORWARDERS" from the "Variable Scope Multicast Addresses" 1031 sub-registry of the "INTERNET PROTOCOL VERSION 6 MULTICAST ADDRESSES" 1032 registry. 1034 13. Security Considerations 1036 MPL uses sequence numbers to maintain a total ordering of MPL Data 1037 Messages from an MPL Seed. The use of sequence numbers allows a 1038 denial-of-service attack where an attacker can spoof a message with a 1039 sufficiently large sequence number to: (i) flush messages from the 1040 Buffered Message List and (ii) increase the MinSequence value for an 1041 MPL Seed in the corresponding Seed Set. The former side effect 1042 allows an attacker to halt the forwarding process of any MPL Data 1043 Messages being disseminated. The latter side effect allows an 1044 attacker to prevent MPL Forwarders from accepting new MPL Data 1045 Messages that an MPL Seed generates while the sequence number is less 1046 than MinSequence. 1048 More generally, the basic ability to inject messages into a Low-power 1049 and Lossy Network can be used as a denial-of-service attack 1050 regardless of what forwarding protocol is used. For these reasons, 1051 Low-power and Lossy Networks typically employ link-layer security 1052 mechanisms to disable an attacker's ability to inject messages. 1054 To prevent attackers from injecting packets through an MPL Forwarder, 1055 the MPL Forwarder MUST NOT accept or forward MPL Data Messages from a 1056 communication interface that does not subscribe to the MPL Domain 1057 Address identified in message's destination address. 1059 MPL uses the Trickle algorithm to manage message transmissions and 1060 the security considerations described in [RFC6206] apply. 1062 14. References 1064 14.1. Normative References 1066 [I-D.droms-6man-multicast-scopes] 1067 Droms, R., "IPv6 Multicast Address Scopes", draft-droms- 1068 6man-multicast-scopes-02 (work in progress), July 2013. 1070 [RFC1982] Elz, R. and R. Bush, "Serial Number Arithmetic", RFC 1982, 1071 August 1996. 1073 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1074 Requirement Levels", BCP 14, RFC 2119, March 1997. 1076 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1077 (IPv6) Specification", RFC 2460, December 1998. 1079 [RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in 1080 IPv6 Specification", RFC 2473, December 1998. 1082 [RFC2780] Bradner, S. and V. Paxson, "IANA Allocation Guidelines For 1083 Values In the Internet Protocol and Related Headers", BCP 1084 37, RFC 2780, March 2000. 1086 [RFC4007] Deering, S., Haberman, B., Jinmei, T., Nordmark, E., and 1087 B. Zill, "IPv6 Scoped Address Architecture", RFC 4007, 1088 March 2005. 1090 [RFC4443] Conta, A., Deering, S., and M. Gupta, "Internet Control 1091 Message Protocol (ICMPv6) for the Internet Protocol 1092 Version 6 (IPv6) Specification", RFC 4443, March 2006. 1094 [RFC6206] Levis, P., Clausen, T., Hui, J., Gnawali, O., and J. Ko, 1095 "The Trickle Algorithm", RFC 6206, March 2011. 1097 [RFC6282] Hui, J. and P. Thubert, "Compression Format for IPv6 1098 Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, 1099 September 2011. 1101 [RFC6550] Winter, T., Thubert, P., Brandt, A., Hui, J., Kelsey, R., 1102 Levis, P., Pister, K., Struik, R., Vasseur, JP., and R. 1103 Alexander, "RPL: IPv6 Routing Protocol for Low-Power and 1104 Lossy Networks", RFC 6550, March 2012. 1106 14.2. Informative References 1108 [RFC3973] Adams, A., Nicholas, J., and W. Siadak, "Protocol 1109 Independent Multicast - Dense Mode (PIM-DM): Protocol 1110 Specification (Revised)", RFC 3973, January 2005. 1112 [RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas, 1113 "Protocol Independent Multicast - Sparse Mode (PIM-SM): 1114 Protocol Specification (Revised)", RFC 4601, August 2006. 1116 Authors' Addresses 1118 Jonathan W. Hui 1119 Cisco 1120 170 West Tasman Drive 1121 San Jose, California 95134 1122 USA 1124 Phone: +408 424 1547 1125 Email: jonhui@cisco.com 1127 Richard Kelsey 1128 Silicon Labs 1129 25 Thomson Place 1130 Boston, Massachusetts 02210 1131 USA 1133 Phone: +617 951 1225 1134 Email: richard.kelsey@silabs.com