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Kelsey 5 Expires: May 14, 2015 Silicon Labs 6 November 10, 2014 8 Multicast Protocol for Low power and Lossy Networks (MPL) 9 draft-ietf-roll-trickle-mcast-10 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 May 14, 2015. 39 Copyright Notice 41 Copyright (c) 2014 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 . . . . . . . . . . . . . . . . . . . 4 59 4. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 5 60 4.1. MPL Domains . . . . . . . . . . . . . . . . . . . . . . . 5 61 4.2. Information Base Overview . . . . . . . . . . . . . . . . 6 62 4.3. Protocol Overview . . . . . . . . . . . . . . . . . . . . 6 63 4.4. Signaling Overview . . . . . . . . . . . . . . . . . . . 8 64 5. MPL Parameters and Constants . . . . . . . . . . . . . . . . 8 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 Parameters . . . . . . . . . . . . . . . . . . . . . 9 69 6. Protocol Message Formats . . . . . . . . . . . . . . . . . . 11 70 6.1. MPL Option . . . . . . . . . . . . . . . . . . . . . . . 11 71 6.2. MPL Control Message . . . . . . . . . . . . . . . . . . . 13 72 6.3. MPL Seed Info . . . . . . . . . . . . . . . . . . . . . . 14 73 7. Information Base . . . . . . . . . . . . . . . . . . . . . . 15 74 7.1. Local Interface Set . . . . . . . . . . . . . . . . . . . 15 75 7.2. Domain Set . . . . . . . . . . . . . . . . . . . . . . . 15 76 7.3. Seed Set . . . . . . . . . . . . . . . . . . . . . . . . 15 77 7.4. Buffered Message Set . . . . . . . . . . . . . . . . . . 15 78 8. MPL Seed Sequence Numbers . . . . . . . . . . . . . . . . . . 16 79 9. MPL Data Messages . . . . . . . . . . . . . . . . . . . . . . 16 80 9.1. MPL Data Message Generation . . . . . . . . . . . . . . . 16 81 9.2. MPL Data Message Transmission . . . . . . . . . . . . . . 17 82 9.3. MPL Data Message Processing . . . . . . . . . . . . . . . 18 83 10. MPL Control Messages . . . . . . . . . . . . . . . . . . . . 19 84 10.1. MPL Control Message Generation . . . . . . . . . . . . . 19 85 10.2. MPL Control Message Transmission . . . . . . . . . . . . 19 86 10.3. MPL Control Message Processing . . . . . . . . . . . . . 20 87 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 21 88 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21 89 12.1. MPL Option Type . . . . . . . . . . . . . . . . . . . . 22 90 12.2. MPL ICMPv6 Type . . . . . . . . . . . . . . . . . . . . 22 91 12.3. Well-known Multicast Addresses . . . . . . . . . . . . . 22 92 13. Security Considerations . . . . . . . . . . . . . . . . . . . 23 93 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 23 94 14.1. Normative References . . . . . . . . . . . . . . . . . . 23 95 14.2. Informative References . . . . . . . . . . . . . . . . . 24 96 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24 98 1. Introduction 100 Low power and Lossy Networks typically operate with strict resource 101 constraints in communication, computation, memory, and energy. Such 102 resource constraints may preclude the use of existing IPv6 multicast 103 routing and forwarding mechanisms. Traditional IP multicast delivery 104 typically relies on topology maintenance mechanisms to discover and 105 maintain routes to all subscribers of a multicast group (e.g. 106 [RFC3973] [RFC4601]). However, maintaining such topologies in Low 107 power and Lossy Networks (LLNs) is costly and may not be feasible 108 given the available resources. 110 Memory constraints may limit devices to maintaining links/routes to 111 one or a few neighbors. For this reason, the Routing Protocol for 112 LLNs (RPL) specifies both storing and non-storing modes [RFC6550]. 113 The latter allows RPL routers to maintain only one or a few default 114 routes towards a LLN Border Router (LBR) and use source routing to 115 forward messages away from the LBR. For the same reasons, a LLN 116 device may not be able to maintain a multicast routing topology when 117 operating with limited memory. 119 Furthermore, the dynamic properties of wireless networks can make the 120 cost of maintaining a multicast routing topology prohibitively 121 expensive. In wireless environments, topology maintenance may 122 involve selecting a connected dominating set used to forward 123 multicast messages to all nodes in an administrative domain. 124 However, existing mechanisms often require two-hop topology 125 information and the cost of maintaining such information grows 126 polynomially with network density. 128 This document specifies the Multicast Protocol for Low power and 129 Lossy Networks (MPL), which provides IPv6 multicast forwarding in 130 constrained networks. MPL avoids the need to construct or maintain 131 any multicast routing topology, disseminating multicast messages to 132 all MPL Forwarders in an MPL Domain. By using the Trickle algorithm 133 [RFC6206], MPL requires only small, constant state for each MPL 134 device that initiates disseminations. The Trickle algorithm also 135 allows MPL to be density-aware, allowing the communication rate to 136 scale logarithmically with density. 138 2. Terminology 140 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 141 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 142 "OPTIONAL" in this document are to be interpreted as described in 143 [RFC2119]. 145 The following terms are used throughout this document: 147 MPL Forwarder - A router that implements MPL. An MPL Forwarder 148 is equipped with at least one MPL Interface. 150 MPL Interface - An MPL Forwarder's attachment to a 151 communications medium, over which it transmits 152 and receives MPL Data Messages and MPL Control 153 Messages according to this specification. An MPL 154 Interface is assigned one or more unicast 155 addresses and is subscribed to one or more MPL 156 Domain Addresses. 158 MPL Domain Address - A multicast address that identifies the set of 159 MPL Interfaces within an MPL Domain. MPL Data 160 Messages disseminated in an MPL Domain have the 161 associated MPL Domain Address as their 162 destination address. 164 MPL Domain - A scope zone, as defined in [RFC4007], in which 165 MPL Interfaces subscribe to the same MPL Domain 166 Address and participate in disseminating MPL Data 167 Messages. 169 MPL Data Message - A multicast message that is used to communicate 170 a multicast payload between MPL Forwarders within 171 an MPL domain. An MPL Data Message contains an 172 MPL Option in the IPv6 header and has as its 173 destination address the MPL Domain Address 174 corresponding to the MPL Domain. 176 MPL Control Message - A link-local multicast message that is used to 177 communicate information about recently received 178 MPL Data Messages to neighboring MPL Forwarders. 180 MPL Seed - An MPL Forwarder that generates MPL Data 181 Messages and serves as an entry point into an MPL 182 Domain. 184 MPL Seed Identifier - An unsigned integer that uniquely identifies an 185 MPL Seed within an MPL Domain. 187 3. Applicability Statement 189 MPL is an IPv6 multicast forwarding protocol designed for the 190 communication characteristics and resource constraints of Low-Power 191 and Lossy Networks. By implementing controlled disseminations of 192 multicast messages using the Trickle algorithm, MPL is designed for 193 networks that communicate using low-power and lossy links with widely 194 varying topologies in both the space and time dimensions. 196 While designed specifically for Low-Power and Lossy Networks, MPL is 197 not limited to use over such networks. MPL may be applicable to any 198 network where no multicast routing state is desired. MPL may also be 199 used in environments where only a subset of links are considered Low- 200 Power and Lossy links. 202 MPL is parameterized to support different dissemination techniques. 203 In one parameterization, MPL may utilize the classic flooding method 204 that involves having each device receiving a message rebroadcast the 205 message. In another parameterization, MPL may utilize Trickle's 206 [RFC6206] "polite gossip" method that involves transmission 207 suppression and adaptive timing techniques. By supporting both 208 simple flooding and Trickle methods, MPL can be configured to operate 209 well in a variety of situations [Clausen2013]. 211 A host need not be aware that their multicast is supported by MPL as 212 long as its attachment router forwards multicast messages between the 213 MPL Domain and the host. However, a host may choose to implement MPL 214 so that it can take advantage of the broadcast medium inherent in 215 many Low-Power and Lossy Networks and receive multicast messages 216 carried by MPL directly. 218 4. Protocol Overview 220 The goal of MPL is to deliver multicast messages to all interfaces 221 that subscribe to the multicast messages' destination address within 222 an MPL Domain. 224 4.1. MPL Domains 226 An MPL Domain is a scope zone, as defined in [RFC4007], in which MPL 227 Interfaces subscribe to the same MPL Domain Address and participate 228 in disseminating MPL Data Messages. 230 By default, an MPL Forwarder SHOULD participate in an MPL Domain 231 identified by the ALL_MPL_FORWARDERS multicast address with a scope 232 value of 3 (Realm-Local) [I-D.ietf-6man-multicast-scopes]. 234 When MPL is used in deployments that use administratively defined 235 scopes that cover, for example, multiple subnets based on different 236 underlying network technologies, Admin-Local scope (scop value 4) or 237 Site-Local scope (scop value 5) SHOULD be used. 239 An MPL Forwarder MAY participate in additional MPL Domains identified 240 by other multicast addresses. An MPL Interface MUST subscribe to the 241 MPL Domain Addresses for the MPL Domains that it participates in. 242 The assignment of other multicast addresses is out of scope. 244 For each MPL Domain Address that an MPL Interface subscribes to, the 245 MPL Interface MUST also subscribe to the same MPL Domain Address with 246 a scope value of 2 (link-local) when reactive forwarding is in use 247 (i.e. when communicating MPL Control Messages). 249 4.2. Information Base Overview 251 A node records necessary protocol state in the following information 252 sets: 254 o The Local Interface Set records the set of local MPL Interfaces 255 and the unicast addresses assigned to those MPL Interfaces. 257 o The Domain Set records the set of MPL Domain Addresses and the 258 local MPL Interfaces that subscribe to those addresses. 260 o A Seed Set records information about received MPL Data Messages 261 received from an MPL Seed within an MPL Domain. Each MPL Domain 262 has an associated Seed Set. A Seed Set maintains the minimum 263 sequence number for MPL Data Messages that the MPL Forwarder is 264 willing to receive or has buffered in its Buffered Message Set 265 from an MPL Seed. MPL uses Seed Sets and Buffered Message Sets to 266 determine when to accept an MPL Data Message, process its payload, 267 and retransmit it. 269 o A Buffered Message Set records recently received MPL Data Messages 270 from an MPL Seed within an MPL Domain. Each MPL Domain has an 271 associated Buffered Message Set. MPL Data Messages resident in a 272 Buffered Message Set have sequence numbers that are greater than 273 or equal to the minimum threshold maintained in the corresponding 274 Seed Set. MPL uses Buffered Message Sets to store MPL Data 275 Messages that may be transmitted by the MPL Forwarder for 276 forwarding. 278 4.3. Protocol Overview 280 MPL achieves its goal by implementing a controlled flood that 281 attempts to disseminate the multicast data message to all interfaces 282 within an MPL Domain. MPL performs the following tasks to 283 disseminate a multicast message: 285 o When having a multicast message to forward into an MPL Domain, the 286 MPL Seed generates an MPL Data Message that includes the MPL 287 Domain Address as the IPv6 Destination Address, the MPL Seed 288 Identifier, a newly generated sequence number, and the multicast 289 message. If the multicast destination address is not the MPL 290 Domain Address, IP-in-IP [RFC2473] is used to encapsulate the 291 multicast message in an MPL Data Message, preserving the original 292 IPv6 Destination Address. 294 o Upon receiving an MPL Data Message, the MPL Forwarder extracts the 295 MPL Seed and sequence number and determines whether or not the MPL 296 Data Message was previously received using the MPL Domain's Seed 297 Set and Buffered Message Set. 299 * If the sequence number is less than the lower-bound sequence 300 number maintained in the Seed Set or a message with the same 301 sequence number exists within the Buffered Message Set, the MPL 302 Forwarder marks the MPL Data Message as old. 304 * Otherwise, the MPL Forwarder marks the MPL Data Message as new. 306 o For each newly received MPL Data Message, an MPL Forwarder updates 307 the Seed Set, adds the MPL Data Message into the Buffered Message 308 Set, processes its payload, and multicasts the MPL Data Message a 309 number of times on all MPL Interfaces participating in the same 310 MPL Domain to forward the message. 312 o Each MPL Forwarder may periodically link-local multicast MPL 313 Control Messages on MPL Interfaces to communicate information 314 contained in an MPL Domain's Seed Set and Buffered Message Set. 316 o Upon receiving an MPL Control Message, an MPL Forwarder determines 317 whether there are any new MPL Data Messages that have yet to be 318 received by the MPL Control Message's source and multicasts those 319 MPL Data Messages. 321 MPL's configuration parameters allow two forwarding strategies for 322 disseminating MPL Data Messages via MPL Interfaces. 324 Proactive Forwarding - With proactive forwarding, an MPL Forwarder 325 schedules transmissions of MPL Data Messages using the Trickle 326 algorithm, without any prior indication that neighboring nodes 327 have yet to receive the message. After transmitting the MPL Data 328 Message a limited number of times, the MPL Forwarder may terminate 329 proactive forwarding for the MPL Data Message. 331 Reactive Forwarding - With reactive forwarding, an MPL Forwarder 332 link-local multicasts MPL Control Messages using the Trickle 333 algorithm [RFC6206]. MPL Forwarders use MPL Control Messages to 334 discover new MPL Data Messages that have not yet been received. 335 When discovering that a neighboring MPL Forwarder has not yet 336 received an MPL Data Message, the MPL Forwarder schedules those 337 MPL Data Messages for transmission using the Trickle algorithm. 339 Note that the use of proactive and reactive forwarding strategies 340 within the same MPL Domain are not mutually exclusive and may be used 341 simultaneously. For example, upon receiving a new MPL Data Message 342 when both proactive and reactive forwarding techniques are enabled, 343 an MPL Forwarder will proactively retransmit the MPL Data Message a 344 limited number of times and schedule further transmissions upon 345 receiving MPL Control Messages. 347 4.4. Signaling Overview 349 MPL generates and processes the following messages: 351 MPL Data Message - Generated by an MPL Seed to deliver a multicast 352 message across an MPL Domain. The MPL Data Message's source is an 353 address in the Local Interface Set of the MPL Seed that generated 354 the message and is valid within the MPL Domain. The MPL Data 355 Message's destination is the MPL Domain Address corresponding to 356 the MPL Domain. An MPL Data Message contains: 358 * The Seed Identifier of the MPL Seed that generated the MPL Data 359 Message. 361 * The sequence number of the MPL Seed that generated the MPL Data 362 Message. 364 * The original multicast message. 366 MPL Control Message - Generated by an MPL Forwarder to communicate 367 information contained in an MPL Domain's Seed Set and Buffered 368 Message Set to neighboring MPL Forwarders. An MPL Control Message 369 contains a list of tuples for each entry in the Seed Set. Each 370 tuple contains: 372 * The minimum sequence number maintained in the Seed Set for the 373 MPL Seed. 375 * A bit-vector indicating the sequence numbers of MPL Data 376 Messages resident in the Buffered Message Set for the MPL Seed, 377 where the first bit represents a sequence number equal to the 378 minimum threshold maintained in the Seed Set. 380 * The length of the bit-vector. 382 5. MPL Parameters and Constants 384 This section describes various program and networking parameters and 385 constants used by MPL. 387 5.1. MPL Multicast Addresses 389 MPL makes use of MPL Domain Addresses to identify MPL Interfaces of 390 an MPL Domain. By default, MPL Forwarders subscribe to the 391 ALL_MPL_FORWARDERS multicast address with a scope value of 3 392 [I-D.ietf-6man-multicast-scopes]. 394 For each MPL Domain Address that an MPL Interface subscribes to, the 395 MPL Interface MUST also subscribe to the MPL Domain Address with a 396 scope value of 2 (link-local) when reactive forwarding is in use. 397 MPL Forwarders use the link-scoped MPL Domain Address to communicate 398 MPL Control Messages to neighboring (i.e. on-link) MPL Forwarders. 400 5.2. MPL Message Types 402 MPL defines an IPv6 Option for carrying an MPL Seed Identifier and a 403 sequence number within an MPL Data Message. The IPv6 Option Type has 404 value 0x6D. 406 MPL defines an ICMPv6 Message (MPL Control Message) for communicating 407 information contained in an MPL Domain's Seed Set and Buffered 408 Message Set to neighboring MPL Forwarders. The MPL Control Message 409 has ICMPv6 Type MPL_ICMP_TYPE. 411 5.3. MPL Seed Identifiers 413 MPL uses MPL Seed Identifiers to uniquely identify MPL Seeds within 414 an MPL Domain. For each MPL Domain that the MPL Forwarder serves as 415 an MPL Seed, the MPL Forwarder MUST have an associated MPL Seed 416 Identifier. An MPL Forwarder MAY use the same MPL Seed Identifier 417 across multiple MPL Domains, but the MPL Seed Identifier MUST be 418 unique within each MPL Domain. The mechanism for assigning and 419 verifying uniqueness of MPL Seed Identifiers is not specified in this 420 document. 422 5.4. MPL Parameters 424 PROACTIVE_FORWARDING A boolean value that indicates whether the MPL 425 Forwarder schedules MPL Data Message transmissions after receiving 426 them for the first time. PROACTIVE_FORWARDING has a default value 427 of TRUE. The mechanism for setting PROACTIVE_FORWARDING is not 428 specified within this document. 430 SEED_SET_ENTRY_LIFETIME The minimum lifetime for an entry in the 431 Seed Set. SEED_SET_ENTRY_LIFETIME has a default value of 30 432 minutes. It is RECOMMENDED that all MPL Forwarders use the same 433 value for SEED_SET_ENTRY_LIFETIME for a given MPL Domain and use a 434 default value of 30 minutes. The mechanism for setting 435 SEED_SET_ENTRY_LIFETIME is not specified within this document. 437 As specified in [RFC6206], a Trickle timer runs for a defined 438 interval and has three configuration parameters: the minimum interval 439 size Imin, the maximum interval size Imax, and a redundancy constant 440 k. 442 This specification defines a fourth Trickle configuration parameter, 443 TimerExpirations, which indicates the number of Trickle timer 444 expiration events that occur before terminating the Trickle algorithm 445 for a given MPL Data Message or MPL Control Message. 447 Each MPL Interface uses the following Trickle parameters for MPL Data 448 Message and MPL Control Message transmissions. 450 DATA_MESSAGE_IMIN The minimum Trickle timer interval, as defined in 451 [RFC6206], for MPL Data Message transmissions. DATA_MESSAGE_IMIN 452 has a default value of 10 times the expected link-layer latency. 454 DATA MESSAGE_IMAX The maximum Trickle timer interval, as defined in 455 [RFC6206], for MPL Data Message transmissions. DATA_MESSAGE_IMAX 456 has a default value equal to DATA_MESSAGE_IMIN. 458 DATA_MESSAGE_K The redundancy constant, as defined in [RFC6206], for 459 MPL Data Message transmissions. DATA_MESSAGE_K has a default 460 value of 1. 462 DATA_MESSAGE_TIMER_EXPIRATIONS The number of Trickle timer 463 expirations that occur before terminating the Trickle algorithm's 464 retransmission of a given MPL Data Message. 465 DATA_MESSAGE_TIMER_EXPIRATIONS has a default value of 3. 467 CONTROL_MESSAGE_IMIN The minimum Trickle timer interval, as defined 468 in [RFC6206], for MPL Control Message transmissions. 469 CONTROL_MESSAGE_IMIN has a default value of 10 times the worst- 470 case link-layer latency. 472 CONTROL_MESSAGE_IMAX The maximum Trickle timer interval, as defined 473 in [RFC6206], for MPL Control Message transmissions. 474 CONTROL_MESSAGE_IMAX has a default value of 5 minutes. 476 CONTROL_MESSAGE_K The redundancy constant, as defined in [RFC6206], 477 for MPL Control Message transmissions. CONTROL_MESSAGE_K has a 478 default value of 1. 480 CONTROL_MESSAGE_TIMER_EXPIRATIONS The number of Trickle timer 481 expirations that occur before terminating the Trickle algorithm 482 for MPL Control Message transmissions. 483 CONTROL_MESSAGE_TIMER_EXPIRATIONS has a default value of 10. 485 As described in [RFC6206], if different nodes have different 486 configuration parameters, Trickle may have unintended behaviors. 487 Therefore, it is RECOMMENDED that all MPL Interfaces attached to the 488 same link of a given MPL Domain use the same values for the Trickle 489 Parameters above for a given MPL Domain. The mechanism for setting 490 the Trickle Parameters is not specified within this document. 492 The default MPL parameters specify a forwarding strategy that 493 utilizes both proactive and reactive techniques. Using these default 494 values, an MPL Forwarder proactively transmits any new MPL Data 495 Messages it receives then uses MPL Control Messages to trigger 496 additional MPL Data Message retransmissions where message drops are 497 detected. Setting DATA_MESSAGE_IMAX to the same as DATA_MESSAGE_IMIN 498 in this case is acceptable since subsequent MPL Data Message 499 retransmissions are triggered by MPL Control Messages, where 500 CONTROL_MESSAGE_IMAX is greater than CONTROL_MESSAGE_IMIN. 502 6. Protocol Message Formats 504 The protocol messages generated and processed by an MPL Forwarder are 505 described in this section. 507 6.1. MPL Option 509 The MPL Option is carried in MPL Data Messages in an IPv6 Hop-by-Hop 510 Options header, immediately following the IPv6 header. The MPL 511 Option has the following format: 513 0 1 2 3 514 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 1 515 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 516 | Option Type | Opt Data Len | 517 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 518 | S |M|V| rsv | sequence | seed-id (optional) | 519 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 521 Option Type 0x6D. 523 Opt Data Len Length of the Option Data field in octets. 525 S 2-bit unsigned integer. Identifies the length of 526 seed-id. 0 indicates that the seed-id is the 527 IPv6 Source Address and not included in the MPL 528 Option. 1 indicates that the seed-id is a 16-bit 529 unsigned integer. 2 indicates that the seed-id 530 is a 64-bit unsigned integer. 3 indicates that 531 the seed-id is a 128-bit unsigned integer. 533 M 1-bit flag. 1 indicates that the value in 534 sequence is known to be the largest sequence 535 number that was received from the MPL Seed. 537 V 1-bit flag. 0 indicates that the MPL Option 538 conforms to this specification. MPL Data 539 Messages with an MPL Option in which this flag is 540 1 MUST be dropped. 542 rsv 4-bit reserved field. MUST be set to 0 on 543 transmission and ignored on reception. 545 sequence 8-bit unsigned integer. Identifies relative 546 ordering of MPL Data Messages from the MPL Seed 547 identified by seed-id. 549 seed-id Uniquely identifies the MPL Seed that initiated 550 dissemination of the MPL Data Message. The size 551 of seed-id is indicated by the S field. 553 The Option Data (in particular the M flag) of the MPL Option is 554 updated by MPL Forwarders as the MPL Data Message is forwarded. 555 Nodes that do not understand the MPL Option MUST discard the MPL Data 556 Message. Thus, according to [RFC2460] the three high order bits of 557 the Option Type are set to '011'. The Option Data length is 558 variable. 560 The seed-id uniquely identifies an MPL Seed. When seed-id is 128 561 bits (S=3), the MPL seed MAY use an IPv6 address assigned to one of 562 its interfaces that is unique within the MPL Domain. Managing MPL 563 Seed Identifiers is not within scope of this document. 565 The sequence field establishes a total ordering of MPL Data Messages 566 generated by an MPL Seed for an MPL Domain. The MPL Seed MUST 567 increment the sequence field's value on each new MPL Data Message 568 that it generates for an MPL Domain. Implementations MUST follow the 569 Serial Number Arithmetic as defined in [RFC1982] when incrementing a 570 sequence value or comparing two sequence values. 572 Future updates to this specification may define additional fields 573 following the seed-id field. 575 6.2. MPL Control Message 577 An MPL Forwarder uses ICMPv6 messages to communicate information 578 contained in an MPL Domain's Seed Set and Buffered Message Set to 579 neighboring MPL Forwarders. The MPL Control Message has the 580 following format: 582 0 1 2 3 583 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 1 584 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 585 | Type | Code | Checksum | 586 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 587 | | 588 . MPL Seed Info[0..n] . 589 . . 590 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 592 IP Fields: 594 Source Address An IPv6 address in the AddressSet of the 595 corresponding MPL Interface and MUST be valid 596 within the MPL Domain. 598 Destination Address The link-scoped MPL Domain Address corresponding 599 to the MPL Domain. 601 Hop Limit 255 603 ICMPv6 Fields: 605 Type MPL_ICMP_TYPE 607 Code 0 609 Checksum The ICMP checksum. See [RFC4443]. 611 MPL Seed Info[0..n] List of zero or more MPL Seed Info entries. 613 The MPL Control Message indicates the sequence numbers of MPL Data 614 Messages that are within the MPL Domain's Buffered Message Set. The 615 MPL Control Message also indicates the sequence numbers of MPL Data 616 Messages that an MPL Forwarder is willing to receive. The MPL 617 Control Message allows neighboring MPL Forwarders to determine 618 whether there are any new MPL Data Messages to exchange. 620 6.3. MPL Seed Info 622 An MPL Seed Info encodes the minimum sequence number for an MPL Seed 623 maintained in the MPL Domain's Seed Set. The MPL Seed Info also 624 indicates the sequence numbers of MPL Data Messages generated by the 625 MPL Seed that are stored within the MPL Domain's Buffered Message 626 Set. The MPL Seed Info has the following format: 628 0 1 2 3 629 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 630 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 631 | min-seqno | bm-len | S | seed-id (0/2/8/16 octets) | 632 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 633 | | 634 . buffered-mpl-messages (variable length) . 635 . . 636 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 638 min-seqno 8-bit unsigned integer. The lower-bound sequence 639 number for the MPL Seed. 641 bm-len 6-bit unsigned integer. The size of buffered- 642 mpl-messages in octets. 644 S 2-bit unsigned integer. Identifies the length of 645 seed-id. 0 indicates that the seed-id value is 646 the IPv6 Source Address and not included in the 647 MPL Seed Info. 1 indicates that the seed-id 648 value is a 16-bit unsigned integer. 2 indicates 649 that the seed-id value is a 64-bit unsigned 650 integer. 3 indicates that the seed-id is a 651 128-bit unsigned integer. 653 seed-id Variable-length unsigned integer. Indicates the 654 MPL Seed associated with this MPL Seed Info. 656 buffered-mpl-messages Variable-length bit vector. Identifies the 657 sequence numbers of MPL Data Messages maintained 658 in the corresponding Buffered Message Set for the 659 MPL Seed. The i'th bit represents a sequence 660 number of min-seqno + i. '0' indicates that the 661 corresponding MPL Data Message does not exist in 662 the Buffered Message Set. '1' indicates that the 663 corresponding MPL Data Message does exist in the 664 Buffered Message Set. 666 The MPL Seed Info does not have any octet alignment requirement. 668 7. Information Base 670 7.1. Local Interface Set 672 The Local Interface Set records the local MPL Interfaces of an MPL 673 Forwarder. The Local Interface Set consists of Local Interface 674 Tuples, one per MPL Interface: (AddressSet). 676 AddressSet - a set of unicast addresses assigned to the MPL 677 Interface. 679 7.2. Domain Set 681 The Domain Set records the MPL Interfaces that subscribe to each MPL 682 Domain Address. The Domain Set consists of MPL Domain Tuples, one 683 per MPL Domain: (MPLInterfaceSet). 685 MPLInterfaceSet - a set of MPL Interfaces that subscribe to the MPL 686 Domain Address that identifies the MPL Domain. 688 7.3. Seed Set 690 A Seed Set records a sliding window used to determine the sequence 691 numbers of MPL Data Messages that an MPL Forwarder is willing to 692 accept generated by the MPL Seed. An MPL Forwarder maintains a Seed 693 Set for each MPL Domain that it participates in. A Seed Set consists 694 of MPL Seed Tuples: (SeedID, MinSequence, Lifetime). 696 SeedID - the identifier for the MPL Seed. 698 MinSequence - a lower-bound sequence number that represents the 699 sequence number of the oldest MPL Data Message the MPL Forwarder 700 is willing to receive or transmit. An MPL Forwarder MUST ignore 701 any MPL Data Message that has sequence value less than than 702 MinSequence. 704 Lifetime - indicates the minimum remaining lifetime of the Seed Set 705 entry. An MPL Forwarder MUST NOT free a Seed Set entry before the 706 remaining lifetime expires. 708 7.4. Buffered Message Set 710 A Buffered Message Set records recently received MPL Data Messages 711 from an MPL Seed within an MPL Domain. An MPL Forwarder uses a 712 Buffered Message Set to buffer MPL Data Messages while the MPL 713 Forwarder is forwarding the MPL Data Messages. An MPL Forwarder 714 maintains a Buffered Message Set for each MPL Domain that it 715 participates in. A Buffered Message Set consists of Buffered Message 716 Tuples: (SeedID, SequenceNumber, DataMessage). 718 SeedID - the identifier for the MPL Seed that generated the MPL Data 719 Message. 721 SequenceNumber - the sequence number for the MPL Data Message. 723 DataMessage - the MPL Data Message. 725 All MPL Data Messages within a Buffered Message Set MUST have a 726 sequence number greater than or equal to MinSequence for the 727 corresponding SeedID. When increasing MinSequence for an MPL Seed, 728 the MPL Forwarder MUST delete any MPL Data Messages from the 729 corresponding Buffered Message Set that have sequence numbers less 730 than MinSequence. 732 8. MPL Seed Sequence Numbers 734 Each MPL Seed maintains a sequence number for each MPL Domain that it 735 serves. The sequence numbers are included in MPL Data Messages 736 generated by the MPL Seed. The MPL Seed MUST increment the sequence 737 number for each MPL Data Message that it generates for an MPL Domain. 738 Implementations MUST follow the Serial Number Arithmetic as defined 739 in [RFC1982] when incrementing a sequence value or comparing two 740 sequence values. This sequence number is used to establish a total 741 ordering of MPL Data Messages generated by an MPL Seed for an MPL 742 Domain. 744 9. MPL Data Messages 746 9.1. MPL Data Message Generation 748 MPL Data Messages are generated by MPL Seeds when these messages 749 enter the MPL Domain. All MPL Data messages have the following 750 properties: 752 o The IPv6 Source Address MUST be an address in the AddressSet of a 753 corresponding MPL Interface and MUST be valid within the MPL 754 Domain. 756 o The IPv6 Destination Address MUST be set to the MPL Domain Address 757 corresponding to the MPL Domain. 759 o An MPL Data Message MUST contain an MPL Option in its IPv6 Header 760 to identify the MPL Seed that generated the message and the 761 ordering relative to other MPL Data Messages generated by the MPL 762 Seed. 764 When the destination address is an MPL Domain Address and the source 765 address is in the AddressLIst of an MPL Interface that belongs to 766 that MPL Domain Address, the application message and the MPL Data 767 Message MAY be identical. In other words, the MPL Data Message may 768 contain a single IPv6 header that includes the MPL Option. 770 Otherwise, IPv6-in-IPv6 encapsulation MUST be used to satisfy the MPL 771 Data Message requirements listed above [RFC2473]. The complete IPv6- 772 in-IPv6 message forms an MPL Data Message. The outer IPv6 header 773 conforms to the MPL Data Message requirements listed above. The 774 encapsulated IPv6 datagram encodes the multicast data message that is 775 communicated beyond the MPL Domain. 777 9.2. MPL Data Message Transmission 779 An MPL Forwarder manages transmission of MPL Data Messages in its 780 Buffered Message Sets using the Trickle algorithm [RFC6206]. An MPL 781 Forwarder MUST use a separate Trickle timer for each MPL Data Message 782 that it is actively forwarding. In accordance with Section 5 of RFC 783 6206 [RFC6206], this document defines the following: 785 o This document defines a "consistent" transmission as receiving an 786 MPL Data Message that has the same MPL Domain Address, seed-id, 787 and sequence value as the MPL Data Message managed by the Trickle 788 timer. 790 o This document defines an "inconsistent" transmission as receiving 791 an MPL Data Message that has the same MPL Domain Address, seed-id 792 value, and the M flag set, but has a sequence value less than MPL 793 Data Message managed by the Trickle timer. 795 o This document does not define any external "events". 797 o This document defines MPL Data Messages as Trickle messages. 799 o The actions outside the Trickle algorithm that the protocol takes 800 involve managing the MPL Domain's Seed Set and Buffered Message 801 Set. 803 As specified in [RFC6206], a Trickle timer has three variables: the 804 current interval size I, a time within the current interval t, and a 805 counter c. MPL defines a fourth variable, e, which counts the number 806 of Trickle timer expiration events since the Trickle timer was last 807 reset. 809 After DATA_MESSAGE_TIMER_EXPIRATIONS Trickle timer events, the MPL 810 Forwarder MUST disable the Trickle timer. When a buffered MPL Data 811 Message does not have an associated Trickle timer, the MPL Forwarder 812 MAY delete the message from the Buffered Message Set by advancing 813 MinSequence of the corresponding MPL Seed in the Seed Set. When the 814 MPL Forwarder no longer buffers any messages for an MPL Seed, the MPL 815 Forwarder MUST NOT increment MinSequence for that MPL Seed. 817 When transmitting an MPL Data Message, the MPL Forwarder MUST either 818 set the M flag to zero or set it to a level that indicates whether or 819 not the message's sequence number is the largest value that has been 820 received from the MPL Seed. 822 9.3. MPL Data Message Processing 824 Upon receiving an MPL Data Message, the MPL Forwarder first processes 825 the MPL Option and updates the Trickle timer associated with the MPL 826 Data Message if one exists. 828 Upon receiving an MPL Data Message, an MPL Forwarder MUST perform one 829 of the following actions: 831 o Accept the message and enter the MPL Data Message in the MPL 832 Domain's Buffered Message Set. 834 o Accept the message and update the corresponding MinSequence in the 835 MPL Domain's Seed Set to 1 greater than the message's sequence 836 number. 838 o Discard the message without any change to the MPL Information 839 Base. 841 If a Seed Set entry exists for the MPL Seed, the MPL Forwarder MUST 842 discard the MPL Data Message if its sequence number is less than 843 MinSequence or exists in the Buffered Message Set. 845 If a Seed Set entry does not exist for the MPL Seed, the MPL 846 Forwarder MUST create a new entry for the MPL Seed before accepting 847 the MPL Data Message. 849 If memory is limited, an MPL Forwarder SHOULD reclaim memory 850 resources by: 852 o Incrementing MinSequence entries in a Seed Set and deleting MPL 853 Data Messages in the corresponding Buffered Message Set that fall 854 below the MinSequence value. 856 o Deleting other Seed Set entries that have expired and the 857 corresponding MPL Data Messages in the Buffered Message Set. 859 If the MPL Forwarder accepts the MPL Data Message, the MPL Forwarder 860 MUST perform the following actions: 862 o Reset the Lifetime of the corresponding Seed Set entry to 863 SEED_SET_ENTRY_LIFETIME. 865 o If PROACTIVE_FORWARDING is true, the MPL Forwarder MUST initialize 866 and start a Trickle timer for the MPL Data Message. 868 o If the MPL Control Message Trickle timer is not running and 869 CONTROL_MESSAGE_TIMER_EXPIRATIONS is non-zero, the MPL Forwarder 870 MUST initialize and start the MPL Control Message Trickle timer. 872 o If the MPL Control Message Trickle timer is running, the MPL 873 Forwarder MUST reset the MPL Control Message Trickle timer. 875 10. MPL Control Messages 877 10.1. MPL Control Message Generation 879 An MPL Forwarder generates MPL Control Messages to communicate an MPL 880 Domain's Seed Set and Buffered Message Set to neighboring MPL 881 Forwarders. Each MPL Control Message is generated according to 882 Section 6.2, with an MPL Seed Info for each entry in the MPL Domain's 883 Seed Set. Each MPL Seed Info entry has the following content: 885 o S set to the size of the seed-id field in the MPL Seed Info entry. 887 o min-seqno set to MinSequence of the MPL Seed. 889 o bm-len set to the size of buffered-mpl-messages in octets. 891 o seed-id set to the MPL seed identifier. 893 o buffered-mpl-messages with each bit representing whether or not an 894 MPL Data Message with the corresponding sequence number exists in 895 the Buffered Message Set. The i'th bit represents a sequence 896 number of min-seqno + i. '0' indicates that the corresponding MPL 897 Data Message does not exist in the Buffered Message Set. '1' 898 indicates that the corresponding MPL Data Message does exist in 899 the Buffered Message Set. 901 10.2. MPL Control Message Transmission 903 An MPL Forwarder transmits MPL Control Messages using the Trickle 904 algorithm. An MPL Forwarder maintains a single Trickle timer for 905 each MPL Domain. When CONTROL_MESSAGE_TIMER_EXPIRATIONS is 0, the 906 MPL Forwarder does not execute the Trickle algorithm and does not 907 transmit MPL Control Messages. In accordance with Section 5 of RFC 908 6206 [RFC6206], this document defines the following: 910 o This document defines a "consistent" transmission as receiving an 911 MPL Control Message that results in a determination that neither 912 the receiving nor transmitting node has any new MPL Data Messages 913 to offer. 915 o This document defines an "inconsistent" transmission as receiving 916 an MPL Control Message that results in a determination that either 917 the receiving or transmitting node has at least one new MPL Data 918 Message to offer. 920 o The Trickle timer is reset in response to external "events." This 921 document defines an "event" as increasing MinSequence of any entry 922 in the corresponding Seed Set or adding a message to the 923 corresponding Buffered Message Set. 925 o This document defines an MPL Control Message as a Trickle message. 927 As specified in [RFC6206], a Trickle timer has three variables: the 928 current interval size I, a time within the current interval t, and a 929 counter c. MPL defines a fourth variable, e, which counts the number 930 of Trickle timer expiration events since the Trickle timer was last 931 reset. After CONTROL_MESSAGE_TIMER_EXPIRATIONS Trickle timer events, 932 the MPL Forwarder MUST disable the Trickle timer. 934 10.3. MPL Control Message Processing 936 An MPL Forwarder processes each MPL Control Message that it receives 937 to determine if it has any new MPL Data Messages to receive or offer. 939 An MPL Forwarder determines if a new MPL Data Message has not been 940 received from a neighboring node if any of the following conditions 941 hold true: 943 o The MPL Control Message includes an MPL Seed that does not exist 944 in the MPL Domain's Seed Set. 946 o The MPL Control Message indicates that the neighbor has an MPL 947 Data Message in its Buffered Message Set with sequence number 948 greater than MinSequence (i.e. the i-th bit is set to 1 and min- 949 seqno + i > MinSequence) and is not included in the MPL Domain's 950 Buffered Message Set. 952 When an MPL Forwarder determines that it has not yet received an MPL 953 Data Message buffered by a neighboring device, the MPL Forwarder MUST 954 reset its Trickle timer associated with MPL Control Message 955 transmissions. If an MPL Control Message Trickle timer is not 956 running, the MPL Forwarder MUST initialize and start a new Trickle 957 timer. 959 An MPL Forwarder determines if an MPL Data Message in the Buffered 960 Message Set has not yet been received by a neighboring MPL Forwarder 961 if any of the following conditions hold true: 963 o The MPL Control Message does not include an MPL Seed for the MPL 964 Data Message. 966 o The MPL Data Message's sequence number is greater than or equal to 967 min-seqno and not included in the neighbor's corresponding 968 Buffered Message Set (i.e. the MPL Data Message's sequence number 969 does not have a corresponding bit in buffered-mpl-messages set to 970 1). 972 When an MPL Forwarder determines that it has at least one MPL Data 973 Message in its corresponding Buffered Message Set that has not yet 974 been received by a neighbor, the MPL Forwarder MUST reset the MPL 975 Control Message Trickle timer. Additionally, for each of those 976 entries in the Buffered Message Set, the MPL Forwarder MUST reset the 977 Trickle timer and reset e to 0. If a Trickle timer is not associated 978 with the MPL Data Message, the MPL Forwarder MUST initialize and 979 start a new Trickle timer. 981 11. Acknowledgements 983 The authors would like to acknowledge the helpful comments of Robert 984 Cragie, Esko Dijk, Ralph Droms, Paul Duffy, Adrian Farrel, Ulrich 985 Herberg, Owen Kirby, Philip Levis, Kerry Lynn, Joseph Reddy, Michael 986 Richardson, Ines Robles, Don Sturek, Dario Tedeschi, and Peter van 987 der Stok, which greatly improved the document. 989 12. IANA Considerations 991 This document defines one IPv6 Option, a type that must be allocated 992 from the IPv6 "Destination Options and Hop-by-Hop Options" registry 993 of [RFC2780]. 995 This document defines one ICMPv6 Message, a type that must be 996 allocated from the "ICMPv6 "type" Numbers" registry of [RFC4443]. 998 This document registers a well-known multicast address from the 999 Variable Scope Multicast Address registry. 1001 12.1. MPL Option Type 1003 IANA is requested to allocate an IPv6 Option Type from the IPv6 1004 "Destination Options and Hop-by-Hop Options" registry of [RFC2780], 1005 as specified in Table 1 below: 1007 +-----------+-----+-----+-------+-------------+---------------+ 1008 | Hex Value | act | chg | rest | Description | Reference | 1009 +-----------+-----+-----+-------+-------------+---------------+ 1010 | 0x6D | 01 | 1 | 01101 | MPL Option | This Document | 1011 +-----------+-----+-----+-------+-------------+---------------+ 1013 Table 1: IPv6 Option Type Allocation 1015 12.2. MPL ICMPv6 Type 1017 IANA is requested to allocate an ICMPv6 Type from the "ICMPv6 "type" 1018 Numbers" registry of [RFC4443], as specified in Table 2 below: 1020 +------+---------------------+---------------+ 1021 | Type | Name | Reference | 1022 +------+---------------------+---------------+ 1023 | TBD | MPL Control Message | This Document | 1024 +------+---------------------+---------------+ 1026 Table 2: IPv6 Option Type Allocation 1028 In this document, the mnemonic MPL_ICMP_TYPE was used to refer to the 1029 ICMPv6 Type above, which is TBD by IANA. 1031 12.3. Well-known Multicast Addresses 1033 IANA is requested to allocate an IPv6 multicast address, with Group 1034 ID in the range [0x01,0xFF] for 6LoWPAN compression [RFC6282], 1035 "ALL_MPL_FORWARDERS" from the "Variable Scope Multicast Addresses" 1036 sub-registry of the "IPv6 Multicast Address Space" registry [RFC3307] 1037 as specified in Table 3 below: 1039 +---------------------+--------------------+-----------+------------+ 1040 | Address(s) | Description | Reference | Date | 1041 | | | | Registered | 1042 +---------------------+--------------------+-----------+------------+ 1043 | FF0X:0:0:0:0:0:0:FC | ALL_MPL_FORWARDERS | This | 2013-04-10 | 1044 | | | Document | | 1045 +---------------------+--------------------+-----------+------------+ 1047 Table 3: Variable Scope Multicast Address Allocation 1049 13. Security Considerations 1051 MPL uses sequence numbers to maintain a total ordering of MPL Data 1052 Messages from an MPL Seed. The use of sequence numbers allows a 1053 denial-of-service attack where an attacker can spoof a message with a 1054 sufficiently large sequence number to: (i) flush messages from the 1055 Buffered Message List and (ii) increase the MinSequence value for an 1056 MPL Seed in the corresponding Seed Set. The former side effect 1057 allows an attacker to halt the forwarding process of any MPL Data 1058 Messages being disseminated. The latter side effect allows an 1059 attacker to prevent MPL Forwarders from accepting new MPL Data 1060 Messages that an MPL Seed generates while the sequence number is less 1061 than MinSequence. 1063 More generally, the basic ability to inject messages into a Low-power 1064 and Lossy Network can be used as a denial-of-service attack 1065 regardless of what forwarding protocol is used. For these reasons, 1066 Low-power and Lossy Networks typically employ link-layer security 1067 mechanisms to disable an attacker's ability to inject messages. 1069 To prevent attackers from injecting packets through an MPL Forwarder, 1070 the MPL Forwarder MUST NOT accept or forward MPL Data Messages from a 1071 communication interface that does not subscribe to the MPL Domain 1072 Address identified in message's destination address. 1074 MPL uses the Trickle algorithm to manage message transmissions and 1075 the security considerations described in [RFC6206] apply. 1077 14. References 1079 14.1. Normative References 1081 [I-D.ietf-6man-multicast-scopes] 1082 Droms, R., "IPv6 Multicast Address Scopes", draft-ietf- 1083 6man-multicast-scopes-07 (work in progress), June 2014. 1085 [RFC1982] Elz, R. and R. Bush, "Serial Number Arithmetic", RFC 1982, 1086 August 1996. 1088 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1089 Requirement Levels", BCP 14, RFC 2119, March 1997. 1091 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1092 (IPv6) Specification", RFC 2460, December 1998. 1094 [RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in 1095 IPv6 Specification", RFC 2473, December 1998. 1097 [RFC2780] Bradner, S. and V. Paxson, "IANA Allocation Guidelines For 1098 Values In the Internet Protocol and Related Headers", BCP 1099 37, RFC 2780, March 2000. 1101 [RFC3307] Haberman, B., "Allocation Guidelines for IPv6 Multicast 1102 Addresses", RFC 3307, August 2002. 1104 [RFC4007] Deering, S., Haberman, B., Jinmei, T., Nordmark, E., and 1105 B. Zill, "IPv6 Scoped Address Architecture", RFC 4007, 1106 March 2005. 1108 [RFC4443] Conta, A., Deering, S., and M. Gupta, "Internet Control 1109 Message Protocol (ICMPv6) for the Internet Protocol 1110 Version 6 (IPv6) Specification", RFC 4443, March 2006. 1112 [RFC6206] Levis, P., Clausen, T., Hui, J., Gnawali, O., and J. Ko, 1113 "The Trickle Algorithm", RFC 6206, March 2011. 1115 [RFC6282] Hui, J. and P. Thubert, "Compression Format for IPv6 1116 Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, 1117 September 2011. 1119 [RFC6550] Winter, T., Thubert, P., Brandt, A., Hui, J., Kelsey, R., 1120 Levis, P., Pister, K., Struik, R., Vasseur, JP., and R. 1121 Alexander, "RPL: IPv6 Routing Protocol for Low-Power and 1122 Lossy Networks", RFC 6550, March 2012. 1124 14.2. Informative References 1126 [Clausen2013] 1127 Clausen, T., Colin de Verdiere, A., and J. Yi, 1128 "Performance Analysis of Trickle as a Flooding Mechanism", 1129 November 2013. 1131 [RFC3973] Adams, A., Nicholas, J., and W. Siadak, "Protocol 1132 Independent Multicast - Dense Mode (PIM-DM): Protocol 1133 Specification (Revised)", RFC 3973, January 2005. 1135 [RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas, 1136 "Protocol Independent Multicast - Sparse Mode (PIM-SM): 1137 Protocol Specification (Revised)", RFC 4601, August 2006. 1139 Authors' Addresses 1140 Jonathan W. Hui 1141 Cisco 1142 170 West Tasman Drive 1143 San Jose, California 95134 1144 USA 1146 Phone: +408 424 1547 1147 Email: jonhui@cisco.com 1149 Richard Kelsey 1150 Silicon Labs 1151 25 Thomson Place 1152 Boston, Massachusetts 02210 1153 USA 1155 Phone: +617 951 1225 1156 Email: richard.kelsey@silabs.com