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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is mentioned on line 1026, but not defined == Missing Reference: '0xFF' is mentioned on line 1026, but not defined == Outdated reference: draft-ietf-6man-multicast-scopes has been published as RFC 7346 ** Obsolete normative reference: RFC 2460 (Obsoleted by RFC 8200) -- Obsolete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 (~~), 4 warnings (==), 2 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: October 16, 2014 Silicon Labs 6 April 14, 2014 8 Multicast Protocol for Low power and Lossy Networks (MPL) 9 draft-ietf-roll-trickle-mcast-09 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 October 16, 2014. 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 . . . . . . . . . . . . . . . . . 8 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 . . . . . . . . . . . . . . . . . . . 12 72 6.3. MPL Seed Info . . . . . . . . . . . . . . . . . . . . . . 13 73 7. Information Base . . . . . . . . . . . . . . . . . . . . . . 14 74 7.1. Local Interface Set . . . . . . . . . . . . . . . . . . . 14 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 . . . . . . . . . . . . . . . . . . . . 21 90 12.2. MPL ICMPv6 Type . . . . . . . . . . . . . . . . . . . . 22 91 12.3. Well-known Multicast Addresses . . . . . . . . . . . . . 22 92 13. Security Considerations . . . . . . . . . . . . . . . . . . . 22 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 A host need not be aware that their multicast is supported by MPL as 203 long as its attachment router forwards multicast messages between the 204 MPL Domain and the host. However, a host may choose to implement MPL 205 so that it can take advantage of the broadcast medium inherent in 206 many Low-Power and Lossy Networks and receive multicast messages 207 carried by MPL directly. 209 4. Protocol Overview 211 The goal of MPL is to deliver multicast messages to all interfaces 212 that subscribe to the multicast messages' destination address within 213 an MPL Domain. 215 4.1. MPL Domains 217 An MPL Domain is a scope zone, as defined in [RFC4007], in which MPL 218 Interfaces subscribe to the same MPL Domain Address and participate 219 in disseminating MPL Data Messages. 221 By default, an MPL Forwarder SHOULD participate in an MPL Domain 222 identified by the ALL_MPL_FORWARDERS multicast address with a scope 223 value of 3 (Realm-Local) [I-D.ietf-6man-multicast-scopes]. 225 When MPL is used in deployments that use administratively defined 226 scopes that cover, for example, multiple subnets based on different 227 underlying network technologies, Admin-Local scope (scop value 4) or 228 Site-Local scope (scop value 5) SHOULD be used. 230 An MPL Forwarder MAY participate in additional MPL Domains identified 231 by other multicast addresses. An MPL Interface MUST subscribe to the 232 MPL Domain Addresses for the MPL Domains that it participates in. 233 The assignment of other multicast addresses is out of scope. 235 For each MPL Domain Address that an MPL Interface subscribes to, the 236 MPL Interface MUST also subscribe to the same MPL Domain Address with 237 a scope value of 2 (link-local) when reactive forwarding is in use 238 (i.e. when communicating MPL Control Messages). 240 4.2. Information Base Overview 242 A node records necessary protocol state in the following information 243 sets: 245 o The Local Interface Set records the set of local MPL Interfaces 246 and the unicast addresses assigned to those MPL Interfaces. 248 o The Domain Set records the set of MPL Domain Addresses and the 249 local MPL Interfaces that subscribe to those addresses. 251 o A Seed Set records information about received MPL Data Messages 252 received from an MPL Seed within an MPL Domain. Each MPL Domain 253 has an associated Seed Set. A Seed Set maintains the minimum 254 sequence number for MPL Data Messages that the MPL Forwarder is 255 willing to receive or has buffered in its Buffered Message Set 256 from an MPL Seed. MPL uses Seed Sets and Buffered Message Sets to 257 determine when to accept an MPL Data Message, process its payload, 258 and retransmit it. 260 o A Buffered Message Set records recently received MPL Data Messages 261 from an MPL Seed within an MPL Domain. Each MPL Domain has an 262 associated Buffered Message Set. MPL Data Messages resident in a 263 Buffered Message Set have sequence numbers that are greater than 264 or equal to the minimum threshold maintained in the corresponding 265 Seed Set. MPL uses Buffered Message Sets to store MPL Data 266 Messages that may be transmitted by the MPL Forwarder for 267 forwarding. 269 4.3. Protocol Overview 271 MPL achieves its goal by implementing a controlled flood that 272 attempts to disseminate the multicast data message to all interfaces 273 within an MPL Domain. MPL performs the following tasks to 274 disseminate a multicast message: 276 o When having a multicast message to forward into an MPL Domain, the 277 MPL Seed generates an MPL Data Message that includes the MPL 278 Domain Address as the IPv6 Destination Address, the MPL Seed 279 Identifier, a newly generated sequence number, and the multicast 280 message. If the multicast destination address is not the MPL 281 Domain Address, IP-in-IP [RFC2473] is used to encapsulate the 282 multicast message in an MPL Data Message, preserving the original 283 IPv6 Destination Address. 285 o Upon receiving an MPL Data Message, the MPL Forwarder extracts the 286 MPL Seed and sequence number and determines whether or not the MPL 287 Data Message was previously received using the MPL Domain's Seed 288 Set and Buffered Message Set. 290 * If the sequence number is less than the lower-bound sequence 291 number maintained in the Seed Set or a message with the same 292 sequence number exists within the Buffered Message Set, the MPL 293 Forwarder marks the MPL Data Message as old. 295 * Otherwise, the MPL Forwarder marks the MPL Data Message as new. 297 o For each newly received MPL Data Message, an MPL Forwarder updates 298 the Seed Set, adds the MPL Data Message into the Buffered Message 299 Set, processes its payload, and multicasts the MPL Data Message a 300 number of times on all MPL Interfaces participating in the same 301 MPL Domain to forward the message. 303 o Each MPL Forwarder may periodically link-local multicast MPL 304 Control Messages on MPL Interfaces to communicate information 305 contained in an MPL Domain's Seed Set and Buffered Message Set. 307 o Upon receiving an MPL Control Message, an MPL Forwarder determines 308 whether there are any new MPL Data Messages that have yet to be 309 received by the MPL Control Message's source and multicasts those 310 MPL Data Messages. 312 MPL's configuration parameters allow two forwarding strategies for 313 disseminating MPL Data Messages via MPL Interfaces. 315 Proactive Forwarding - With proactive forwarding, an MPL Forwarder 316 schedules transmissions of MPL Data Messages using the Trickle 317 algorithm, without any prior indication that neighboring nodes 318 have yet to receive the message. After transmitting the MPL Data 319 Message a limited number of times, the MPL Forwarder may terminate 320 proactive forwarding for the MPL Data Message. 322 Reactive Forwarding - With reactive forwarding, an MPL Forwarder 323 link-local multicasts MPL Control Messages using the Trickle 324 algorithm [RFC6206]. MPL Forwarders use MPL Control Messages to 325 discover new MPL Data Messages that have not yet been received. 326 When discovering that a neighboring MPL Forwarder has not yet 327 received an MPL Data Message, the MPL Forwarder schedules those 328 MPL Data Messages for transmission using the Trickle algorithm. 330 Note that the use of proactive and reactive forwarding strategies 331 within the same MPL Domain are not mutually exclusive and may be used 332 simultaneously. For example, upon receiving a new MPL Data Message 333 when both proactive and reactive forwarding techniques are enabled, 334 an MPL Forwarder will proactively retransmit the MPL Data Message a 335 limited number of times and schedule further transmissions upon 336 receiving MPL Control Messages. 338 4.4. Signaling Overview 340 MPL generates and processes the following messages: 342 MPL Data Message - Generated by an MPL Seed to deliver a multicast 343 message across an MPL Domain. The MPL Data Message's source is an 344 address in the Local Interface Set of the MPL Seed that generated 345 the message and is valid within the MPL Domain. The MPL Data 346 Message's destination is the MPL Domain Address corresponding to 347 the MPL Domain. An MPL Data Message contains: 349 * The Seed Identifier of the MPL Seed that generated the MPL Data 350 Message. 352 * The sequence number of the MPL Seed that generated the MPL Data 353 Message. 355 * The original multicast message. 357 MPL Control Message - Generated by an MPL Forwarder to communicate 358 information contained in an MPL Domain's Seed Set and Buffered 359 Message Set to neighboring MPL Forwarders. An MPL Control Message 360 contains a list of tuples for each entry in the Seed Set. Each 361 tuple contains: 363 * The minimum sequence number maintained in the Seed Set for the 364 MPL Seed. 366 * A bit-vector indicating the sequence numbers of MPL Data 367 Messages resident in the Buffered Message Set for the MPL Seed, 368 where the first bit represents a sequence number equal to the 369 minimum threshold maintained in the Seed Set. 371 * The length of the bit-vector. 373 5. MPL Parameters and Constants 375 This section describes various program and networking parameters and 376 constants used by MPL. 378 5.1. MPL Multicast Addresses 380 MPL makes use of MPL Domain Addresses to identify MPL Interfaces of 381 an MPL Domain. By default, MPL Forwarders subscribe to the 382 ALL_MPL_FORWARDERS multicast address with a scope value of 3 383 [I-D.ietf-6man-multicast-scopes]. 385 For each MPL Domain Address that an MPL Interface subscribes to, the 386 MPL Interface MUST also subscribe to the MPL Domain Address with a 387 scope value of 2 (link-local) when reactive forwarding is in use. 388 MPL Forwarders use the link-scoped MPL Domain Address to communicate 389 MPL Control Messages to neighboring (i.e. on-link) MPL Forwarders. 391 5.2. MPL Message Types 393 MPL defines an IPv6 Option for carrying an MPL Seed Identifier and a 394 sequence number within an MPL Data Message. The IPv6 Option Type has 395 value 0x6D. 397 MPL defines an ICMPv6 Message (MPL Control Message) for communicating 398 information contained in an MPL Domain's Seed Set and Buffered 399 Message Set to neighboring MPL Forwarders. The MPL Control Message 400 has ICMPv6 Type MPL_ICMP_TYPE. 402 5.3. MPL Seed Identifiers 404 MPL uses MPL Seed Identifiers to uniquely identify MPL Seeds within 405 an MPL Domain. For each MPL Domain that the MPL Forwarder serves as 406 an MPL Seed, the MPL Forwarder MUST have an associated MPL Seed 407 Identifier. An MPL Forwarder MAY use the same MPL Seed Identifier 408 across multiple MPL Domains, but the MPL Seed Identifier MUST be 409 unique within each MPL Domain. The mechanism for assigning and 410 verifying uniqueness of MPL Seed Identifiers is not specified in this 411 document. 413 5.4. MPL Parameters 415 PROACTIVE_FORWARDING A boolean value that indicates whether the MPL 416 Forwarder schedules MPL Data Message transmissions after receiving 417 them for the first time. PROACTIVE_FORWARDING has a default value 418 of TRUE. The mechanism for setting PROACTIVE_FORWARDING is not 419 specified within this document. 421 SEED_SET_ENTRY_LIFETIME The minimum lifetime for an entry in the 422 Seed Set. SEED_SET_ENTRY_LIFETIME has a default value of 30 423 minutes. It is RECOMMENDED that all MPL Forwarders use the same 424 value for SEED_SET_ENTRY_LIFETIME for a given MPL Domain and use a 425 default value of 30 minutes. The mechanism for setting 426 SEED_SET_ENTRY_LIFETIME is not specified within this document. 428 As specified in [RFC6206], a Trickle timer runs for a defined 429 interval and has three configuration parameters: the minimum interval 430 size Imin, the maximum interval size Imax, and a redundancy constant 431 k. 433 This specification defines a fourth Trickle configuration parameter, 434 TimerExpirations, which indicates the number of Trickle timer 435 expiration events that occur before terminating the Trickle algorithm 436 for a given MPL Data Message or MPL Control Message. 438 Each MPL Interface uses the following Trickle parameters for MPL Data 439 Message and MPL Control Message transmissions. 441 DATA_MESSAGE_IMIN The minimum Trickle timer interval, as defined in 442 [RFC6206], for MPL Data Message transmissions. DATA_MESSAGE_IMIN 443 has a default value of 10 times the expected link-layer latency. 445 DATA MESSAGE_IMAX The maximum Trickle timer interval, as defined in 446 [RFC6206], for MPL Data Message transmissions. DATA_MESSAGE_IMAX 447 has a default value equal to DATA_MESSAGE_IMIN. 449 DATA_MESSAGE_K The redundancy constant, as defined in [RFC6206], for 450 MPL Data Message transmissions. DATA_MESSAGE_K has a default 451 value of 1. 453 DATA_MESSAGE_TIMER_EXPIRATIONS The number of Trickle timer 454 expirations that occur before terminating the Trickle algorithm's 455 retransmission of a given MPL Data Message. 456 DATA_MESSAGE_TIMER_EXPIRATIONS has a default value of 3. 458 CONTROL_MESSAGE_IMIN The minimum Trickle timer interval, as defined 459 in [RFC6206], for MPL Control Message transmissions. 460 CONTROL_MESSAGE_IMIN has a default value of 10 times the worst- 461 case link-layer latency. 463 CONTROL_MESSAGE_IMAX The maximum Trickle timer interval, as defined 464 in [RFC6206], for MPL Control Message transmissions. 465 CONTROL_MESSAGE_IMAX has a default value of 5 minutes. 467 CONTROL_MESSAGE_K The redundancy constant, as defined in [RFC6206], 468 for MPL Control Message transmissions. CONTROL_MESSAGE_K has a 469 default value of 1. 471 CONTROL_MESSAGE_TIMER_EXPIRATIONS The number of Trickle timer 472 expirations that occur before terminating the Trickle algorithm 473 for MPL Control Message transmissions. 474 CONTROL_MESSAGE_TIMER_EXPIRATIONS has a default value of 10. 476 As described in [RFC6206], if different nodes have different 477 configuration parameters, Trickle may have unintended behaviors. 479 Therefore, it is RECOMMENDED that all MPL Interfaces attached to the 480 same link of a given MPL Domain use the same values for the Trickle 481 Parameters above for a given MPL Domain. The mechanism for setting 482 the Trickle Parameters is not specified within this document. 484 The default MPL parameters specify a forwarding strategy that 485 utilizes both proactive and reactive techniques. Using these default 486 values, an MPL Forwarder proactively transmits any new MPL Data 487 Messages it receives then uses MPL Control Messages to trigger 488 additional MPL Data Message retransmissions where message drops are 489 detected. Setting DATA_MESSAGE_IMAX to the same as DATA_MESSAGE_IMIN 490 in this case is acceptable since subsequent MPL Data Message 491 retransmissions are triggered by MPL Control Messages, where 492 CONTROL_MESSAGE_IMAX is greater than CONTROL_MESSAGE_IMIN. 494 6. Protocol Message Formats 496 The protocol messages generated and processed by an MPL Forwarder are 497 described in this section. 499 6.1. MPL Option 501 The MPL Option is carried in MPL Data Messages in an IPv6 Hop-by-Hop 502 Options header, immediately following the IPv6 header. The MPL 503 Option has the following format: 505 0 1 2 3 506 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 1 507 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 508 | Option Type | Opt Data Len | 509 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 510 | S |M|V| rsv | sequence | seed-id (optional) | 511 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 513 Option Type 0x6D. 515 Opt Data Len Length of the Option Data field in octets. 517 S 2-bit unsigned integer. Identifies the length of 518 seed-id. 0 indicates that the seed-id is the 519 IPv6 Source Address and not included in the MPL 520 Option. 1 indicates that the seed-id is a 16-bit 521 unsigned integer. 2 indicates that the seed-id 522 is a 64-bit unsigned integer. 3 indicates that 523 the seed-id is a 128-bit unsigned integer. 525 M 1-bit flag. 1 indicates that the value in 526 sequence is known to be the largest sequence 527 number that was received from the MPL Seed. 529 V 1-bit flag. 0 indicates that the MPL Option 530 conforms to this specification. MPL Data 531 Messages with an MPL Option in which this flag is 532 1 MUST be dropped. 534 rsv 4-bit reserved field. MUST be set to 0 on 535 transmission and ignored on reception. 537 sequence 8-bit unsigned integer. Identifies relative 538 ordering of MPL Data Messages from the MPL Seed 539 identified by seed-id. 541 seed-id Uniquely identifies the MPL Seed that initiated 542 dissemination of the MPL Data Message. The size 543 of seed-id is indicated by the S field. 545 The Option Data (in particular the M flag) of the MPL Option is 546 updated by MPL Forwarders as the MPL Data Message is forwarded. 547 Nodes that do not understand the MPL Option MUST discard the MPL Data 548 Message. Thus, according to [RFC2460] the three high order bits of 549 the Option Type are set to '011'. The Option Data length is 550 variable. 552 The seed-id uniquely identifies an MPL Seed. When seed-id is 128 553 bits (S=3), the MPL seed MAY use an IPv6 address assigned to one of 554 its interfaces that is unique within the MPL Domain. Managing MPL 555 Seed Identifiers is not within scope of this document. 557 The sequence field establishes a total ordering of MPL Data Messages 558 generated by an MPL Seed for an MPL Domain. The MPL Seed MUST 559 increment the sequence field's value on each new MPL Data Message 560 that it generates for an MPL Domain. Implementations MUST follow the 561 Serial Number Arithmetic as defined in [RFC1982] when incrementing a 562 sequence value or comparing two sequence values. 564 Future updates to this specification may define additional fields 565 following the seed-id field. 567 6.2. MPL Control Message 569 An MPL Forwarder uses ICMPv6 messages to communicate information 570 contained in an MPL Domain's Seed Set and Buffered Message Set to 571 neighboring MPL Forwarders. The MPL Control Message has the 572 following format: 574 0 1 2 3 575 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 1 576 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 577 | Type | Code | Checksum | 578 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 579 | | 580 . MPL Seed Info[0..n] . 581 . . 582 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 584 IP Fields: 586 Source Address An IPv6 address in the AddressSet of the 587 corresponding MPL Interface and MUST be valid 588 within the MPL Domain. 590 Destination Address The link-scoped MPL Domain Address corresponding 591 to the MPL Domain. 593 Hop Limit 255 595 ICMPv6 Fields: 597 Type MPL_ICMP_TYPE 599 Code 0 601 Checksum The ICMP checksum. See [RFC4443]. 603 MPL Seed Info[0..n] List of zero or more MPL Seed Info entries. 605 The MPL Control Message indicates the sequence numbers of MPL Data 606 Messages that are within the MPL Domain's Buffered Message Set. The 607 MPL Control Message also indicates the sequence numbers of MPL Data 608 Messages that an MPL Forwarder is willing to receive. The MPL 609 Control Message allows neighboring MPL Forwarders to determine 610 whether there are any new MPL Data Messages to exchange. 612 6.3. MPL Seed Info 614 An MPL Seed Info encodes the minimum sequence number for an MPL Seed 615 maintained in the MPL Domain's Seed Set. The MPL Seed Info also 616 indicates the sequence numbers of MPL Data Messages generated by the 617 MPL Seed that are stored within the MPL Domain's Buffered Message 618 Set. The MPL Seed Info has the following format: 620 0 1 2 3 621 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 1 622 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 623 | min-seqno | bm-len | S | seed-id (0/2/8/16 octets) | 624 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 625 | | 626 . buffered-mpl-messages (variable length) . 627 . . 628 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 630 min-seqno 8-bit unsigned integer. The lower-bound sequence 631 number for the MPL Seed. 633 bm-len 6-bit unsigned integer. The size of buffered- 634 mpl-messages in octets. 636 S 2-bit unsigned integer. Identifies the length of 637 seed-id. 0 indicates that the seed-id value is 638 the IPv6 Source Address and not included in the 639 MPL Seed Info. 1 indicates that the seed-id 640 value is a 16-bit unsigned integer. 2 indicates 641 that the seed-id value is a 64-bit unsigned 642 integer. 3 indicates that the seed-id is a 643 128-bit unsigned integer. 645 seed-id Variable-length unsigned integer. Indicates the 646 MPL Seed associated with this MPL Seed Info. 648 buffered-mpl-messages Variable-length bit vector. Identifies the 649 sequence numbers of MPL Data Messages maintained 650 in the corresponding Buffered Message Set for the 651 MPL Seed. The i'th bit represents a sequence 652 number of min-seqno + i. '0' indicates that the 653 corresponding MPL Data Message does not exist in 654 the Buffered Message Set. '1' indicates that the 655 corresponding MPL Data Message does exist in the 656 Buffered Message Set. 658 The MPL Seed Info does not have any octet alignment requirement. 660 7. Information Base 662 7.1. Local Interface Set 664 The Local Interface Set records the local MPL Interfaces of an MPL 665 Forwarder. The Local Interface Set consists of Local Interface 666 Tuples, one per MPL Interface: (AddressSet). 668 AddressSet - a set of unicast addresses assigned to the MPL 669 Interface. 671 7.2. Domain Set 673 The Domain Set records the MPL Interfaces that subscribe to each MPL 674 Domain Address. The Domain Set consists of MPL Domain Tuples, one 675 per MPL Domain: (MPLInterfaceSet). 677 MPLInterfaceSet - a set of MPL Interfaces that subscribe to the MPL 678 Domain Address that identifies the MPL Domain. 680 7.3. Seed Set 682 A Seed Set records a sliding window used to determine the sequence 683 numbers of MPL Data Messages that an MPL Forwarder is willing to 684 accept generated by the MPL Seed. An MPL Forwarder maintains a Seed 685 Set for each MPL Domain that it participates in. A Seed Set consists 686 of MPL Seed Tuples: (SeedID, MinSequence, Lifetime). 688 SeedID - the identifier for the MPL Seed. 690 MinSequence - a lower-bound sequence number that represents the 691 sequence number of the oldest MPL Data Message the MPL Forwarder 692 is willing to receive or transmit. An MPL Forwarder MUST ignore 693 any MPL Data Message that has sequence value less than than 694 MinSequence. 696 Lifetime - indicates the minimum remaining lifetime of the Seed Set 697 entry. An MPL Forwarder MUST NOT free a Seed Set entry before the 698 remaining lifetime expires. 700 7.4. Buffered Message Set 702 A Buffered Message Set records recently received MPL Data Messages 703 from an MPL Seed within an MPL Domain. An MPL Forwarder uses a 704 Buffered Message Set to buffer MPL Data Messages while the MPL 705 Forwarder is forwarding the MPL Data Messages. An MPL Forwarder 706 maintains a Buffered Message Set for each MPL Domain that it 707 participates in. A Buffered Message Set consists of Buffered Message 708 Tuples: (SeedID, SequenceNumber, DataMessage). 710 SeedID - the identifier for the MPL Seed that generated the MPL Data 711 Message. 713 SequenceNumber - the sequence number for the MPL Data Message. 715 DataMessage - the MPL Data Message. 717 All MPL Data Messages within a Buffered Message Set MUST have a 718 sequence number greater than or equal to MinSequence for the 719 corresponding SeedID. When increasing MinSequence for an MPL Seed, 720 the MPL Forwarder MUST delete any MPL Data Messages from the 721 corresponding Buffered Message Set that have sequence numbers less 722 than MinSequence. 724 8. MPL Seed Sequence Numbers 726 Each MPL Seed maintains a sequence number for each MPL Domain that it 727 serves. The sequence numbers are included in MPL Data Messages 728 generated by the MPL Seed. The MPL Seed MUST increment the sequence 729 number for each MPL Data Message that it generates for an MPL Domain. 730 Implementations MUST follow the Serial Number Arithmetic as defined 731 in [RFC1982] when incrementing a sequence value or comparing two 732 sequence values. This sequence number is used to establish a total 733 ordering of MPL Data Messages generated by an MPL Seed for an MPL 734 Domain. 736 9. MPL Data Messages 738 9.1. MPL Data Message Generation 740 MPL Data Messages are generated by MPL Seeds when these messages 741 enter the MPL Domain. All MPL Data messages have the following 742 properties: 744 o The IPv6 Source Address MUST be an address in the AddressSet of a 745 corresponding MPL Interface and MUST be valid within the MPL 746 Domain. 748 o The IPv6 Destination Address MUST be set to the MPL Domain Address 749 corresponding to the MPL Domain. 751 o An MPL Data Message MUST contain an MPL Option in its IPv6 Header 752 to identify the MPL Seed that generated the message and the 753 ordering relative to other MPL Data Messages generated by the MPL 754 Seed. 756 When the destination address is an MPL Domain Address and the source 757 address is in the AddressLIst of an MPL Interface that belongs to 758 that MPL Domain Address, the application message and the MPL Data 759 Message MAY be identical. In other words, the MPL Data Message may 760 contain a single IPv6 header that includes the MPL Option. 762 Otherwise, IPv6-in-IPv6 encapsulation MUST be used to satisfy the MPL 763 Data Message requirements listed above [RFC2473]. The complete IPv6 764 -in-IPv6 message forms an MPL Data Message. The outer IPv6 header 765 conforms to the MPL Data Message requirements listed above. The 766 encapsulated IPv6 datagram encodes the multicast data message that is 767 communicated beyond the MPL Domain. 769 9.2. MPL Data Message Transmission 771 An MPL Forwarder manages transmission of MPL Data Messages in its 772 Buffered Message Sets using the Trickle algorithm [RFC6206]. An MPL 773 Forwarder MUST use a separate Trickle timer for each MPL Data Message 774 that it is actively forwarding. In accordance with Section 5 of RFC 775 6206 [RFC6206], this document defines the following: 777 o This document defines a "consistent" transmission as receiving an 778 MPL Data Message that has the same MPL Domain Address, seed-id, 779 and sequence value as the MPL Data Message managed by the Trickle 780 timer. 782 o This document defines an "inconsistent" transmission as receiving 783 an MPL Data Message that has the same MPL Domain Address, seed-id 784 value, and the M flag set, but has a sequence value less than MPL 785 Data Message managed by the Trickle timer. 787 o This document does not define any external "events". 789 o This document defines MPL Data Messages as Trickle messages. 791 o The actions outside the Trickle algorithm that the protocol takes 792 involve managing the MPL Domain's Seed Set and Buffered Message 793 Set. 795 As specified in [RFC6206], a Trickle timer has three variables: the 796 current interval size I, a time within the current interval t, and a 797 counter c. MPL defines a fourth variable, e, which counts the number 798 of Trickle timer expiration events since the Trickle timer was last 799 reset. 801 After DATA_MESSAGE_TIMER_EXPIRATIONS Trickle timer events, the MPL 802 Forwarder MUST disable the Trickle timer. When a buffered MPL Data 803 Message does not have an associated Trickle timer, the MPL Forwarder 804 MAY delete the message from the Buffered Message Set by advancing 805 MinSequence of the corresponding MPL Seed in the Seed Set. When the 806 MPL Forwarder no longer buffers any messages for an MPL Seed, the MPL 807 Forwarder MUST NOT increment MinSequence for that MPL Seed. 809 When transmitting an MPL Data Message, the MPL Forwarder MUST either 810 set the M flag to zero or set it to a level that indicates whether or 811 not the message's sequence number is the largest value that has been 812 received from the MPL Seed. 814 9.3. MPL Data Message Processing 816 Upon receiving an MPL Data Message, the MPL Forwarder first processes 817 the MPL Option and updates the Trickle timer associated with the MPL 818 Data Message if one exists. 820 Upon receiving an MPL Data Message, an MPL Forwarder MUST perform one 821 of the following actions: 823 o Accept the message and enter the MPL Data Message in the MPL 824 Domain's Buffered Message Set. 826 o Accept the message and update the corresponding MinSequence in the 827 MPL Domain's Seed Set to 1 greater than the message's sequence 828 number. 830 o Discard the message without any change to the MPL Information 831 Base. 833 If a Seed Set entry exists for the MPL Seed, the MPL Forwarder MUST 834 discard the MPL Data Message if its sequence number is less than 835 MinSequence or exists in the Buffered Message Set. 837 If a Seed Set entry does not exist for the MPL Seed, the MPL 838 Forwarder MUST create a new entry for the MPL Seed before accepting 839 the MPL Data Message. 841 If memory is limited, an MPL Forwarder SHOULD reclaim memory 842 resources by: 844 o Incrementing MinSequence entries in a Seed Set and deleting MPL 845 Data Messages in the corresponding Buffered Message Set that fall 846 below the MinSequence value. 848 o Deleting other Seed Set entries that have expired and the 849 corresponding MPL Data Messages in the Buffered Message Set. 851 If the MPL Forwarder accepts the MPL Data Message, the MPL Forwarder 852 MUST perform the following actions: 854 o Reset the Lifetime of the corresponding Seed Set entry to 855 SEED_SET_ENTRY_LIFETIME. 857 o If PROACTIVE_FORWARDING is true, the MPL Forwarder MUST initialize 858 and start a Trickle timer for the MPL Data Message. 860 o If the MPL Control Message Trickle timer is not running and 861 CONTROL_MESSAGE_TIMER_EXPIRATIONS is non-zero, the MPL Forwarder 862 MUST initialize and start the MPL Control Message Trickle timer. 864 o If the MPL Control Message Trickle timer is running, the MPL 865 Forwarder MUST reset the MPL Control Message Trickle timer. 867 10. MPL Control Messages 869 10.1. MPL Control Message Generation 871 An MPL Forwarder generates MPL Control Messages to communicate an MPL 872 Domain's Seed Set and Buffered Message Set to neighboring MPL 873 Forwarders. Each MPL Control Message is generated according to 874 Section 6.2, with an MPL Seed Info for each entry in the MPL Domain's 875 Seed Set. Each MPL Seed Info entry has the following content: 877 o S set to the size of the seed-id field in the MPL Seed Info entry. 879 o min-seqno set to MinSequence of the MPL Seed. 881 o bm-len set to the size of buffered-mpl-messages in octets. 883 o seed-id set to the MPL seed identifier. 885 o buffered-mpl-messages with each bit representing whether or not an 886 MPL Data Message with the corresponding sequence number exists in 887 the Buffered Message Set. The i'th bit represents a sequence 888 number of min-seqno + i. '0' indicates that the corresponding MPL 889 Data Message does not exist in the Buffered Message Set. '1' 890 indicates that the corresponding MPL Data Message does exist in 891 the Buffered Message Set. 893 10.2. MPL Control Message Transmission 895 An MPL Forwarder transmits MPL Control Messages using the Trickle 896 algorithm. An MPL Forwarder maintains a single Trickle timer for 897 each MPL Domain. When CONTROL_MESSAGE_TIMER_EXPIRATIONS is 0, the 898 MPL Forwarder does not execute the Trickle algorithm and does not 899 transmit MPL Control Messages. In accordance with Section 5 of RFC 900 6206 [RFC6206], this document defines the following: 902 o This document defines a "consistent" transmission as receiving an 903 MPL Control Message that results in a determination that neither 904 the receiving nor transmitting node has any new MPL Data Messages 905 to offer. 907 o This document defines an "inconsistent" transmission as receiving 908 an MPL Control Message that results in a determination that either 909 the receiving or transmitting node has at least one new MPL Data 910 Message to offer. 912 o The Trickle timer is reset in response to external "events." This 913 document defines an "event" as increasing MinSequence of any entry 914 in the corresponding Seed Set or adding a message to the 915 corresponding Buffered Message Set. 917 o This document defines an MPL Control Message as a Trickle message. 919 As specified in [RFC6206], a Trickle timer has three variables: the 920 current interval size I, a time within the current interval t, and a 921 counter c. MPL defines a fourth variable, e, which counts the number 922 of Trickle timer expiration events since the Trickle timer was last 923 reset. After CONTROL_MESSAGE_TIMER_EXPIRATIONS Trickle timer events, 924 the MPL Forwarder MUST disable the Trickle timer. 926 10.3. MPL Control Message Processing 928 An MPL Forwarder processes each MPL Control Message that it receives 929 to determine if it has any new MPL Data Messages to receive or offer. 931 An MPL Forwarder determines if a new MPL Data Message has not been 932 received from a neighboring node if any of the following conditions 933 hold true: 935 o The MPL Control Message includes an MPL Seed that does not exist 936 in the MPL Domain's Seed Set. 938 o The MPL Control Message indicates that the neighbor has an MPL 939 Data Message in its Buffered Message Set with sequence number 940 greater than MinSequence (i.e. the i-th bit is set to 1 and min- 941 seqno + i > MinSequence) and is not included in the MPL Domain's 942 Buffered Message Set. 944 When an MPL Forwarder determines that it has not yet received an MPL 945 Data Message buffered by a neighboring device, the MPL Forwarder MUST 946 reset its Trickle timer associated with MPL Control Message 947 transmissions. If an MPL Control Message Trickle timer is not 948 running, the MPL Forwarder MUST initialize and start a new Trickle 949 timer. 951 An MPL Forwarder determines if an MPL Data Message in the Buffered 952 Message Set has not yet been received by a neighboring MPL Forwarder 953 if any of the following conditions hold true: 955 o The MPL Control Message does not include an MPL Seed for the MPL 956 Data Message. 958 o The MPL Data Message's sequence number is greater than or equal to 959 min-seqno and not included in the neighbor's corresponding 960 Buffered Message Set (i.e. the MPL Data Message's sequence number 961 does not have a corresponding bit in buffered-mpl-messages set to 962 1). 964 When an MPL Forwarder determines that it has at least one MPL Data 965 Message in its corresponding Buffered Message Set that has not yet 966 been received by a neighbor, the MPL Forwarder MUST reset the MPL 967 Control Message Trickle timer. Additionally, for each of those 968 entries in the Buffered Message Set, the MPL Forwarder MUST reset the 969 Trickle timer and reset e to 0. If a Trickle timer is not associated 970 with the MPL Data Message, the MPL Forwarder MUST initialize and 971 start a new Trickle timer. 973 11. Acknowledgements 975 The authors would like to acknowledge the helpful comments of Robert 976 Cragie, Esko Dijk, Ralph Droms, Paul Duffy, Adrian Farrel, Ulrich 977 Herberg, Owen Kirby, Kerry Lynn, Joseph Reddy, Michael Richardson, 978 Ines Robles, Don Sturek, Dario Tedeschi, and Peter van der Stok, 979 which greatly improved the document. 981 12. IANA Considerations 983 This document defines one IPv6 Option, a type that must be allocated 984 from the IPv6 "Destination Options and Hop-by-Hop Options" registry 985 of [RFC2780]. 987 This document defines one ICMPv6 Message, a type that must be 988 allocated from the "ICMPv6 "type" Numbers" registry of [RFC4443]. 990 This document registers a well-known multicast address from the 991 Variable Scope Multicast Address registry. 993 12.1. MPL Option Type 995 IANA is requested to allocate an IPv6 Option Type from the IPv6 996 "Destination Options and Hop-by-Hop Options" registry of [RFC2780], 997 as specified in Table 1 below: 999 +-----------+-----+-----+-------+-------------+---------------+ 1000 | Hex Value | act | chg | rest | Description | Reference | 1001 +-----------+-----+-----+-------+-------------+---------------+ 1002 | 0x6D | 01 | 1 | 01101 | MPL Option | This Document | 1003 +-----------+-----+-----+-------+-------------+---------------+ 1005 Table 1: IPv6 Option Type Allocation 1007 12.2. MPL ICMPv6 Type 1009 IANA is requested to allocate an ICMPv6 Type from the "ICMPv6 "type" 1010 Numbers" registry of [RFC4443], as specified in Table 2 below: 1012 +------+---------------------+---------------+ 1013 | Type | Name | Reference | 1014 +------+---------------------+---------------+ 1015 | TBD | MPL Control Message | This Document | 1016 +------+---------------------+---------------+ 1018 Table 2: IPv6 Option Type Allocation 1020 In this document, the mnemonic MPL_ICMP_TYPE was used to refer to the 1021 ICMPv6 Type above, which is TBD by IANA. 1023 12.3. Well-known Multicast Addresses 1025 IANA is requested to allocate an IPv6 multicast address, with Group 1026 ID in the range [0x01,0xFF] for 6LoWPAN compression [RFC6282], 1027 "ALL_MPL_FORWARDERS" from the "Variable Scope Multicast Addresses" 1028 sub-registry of the "IPv6 Multicast Address Space" registry [RFC3307] 1029 as specified in Table 3 below: 1031 +---------------------+--------------------+-----------+------------+ 1032 | Address(s) | Description | Reference | Date | 1033 | | | | Registered | 1034 +---------------------+--------------------+-----------+------------+ 1035 | FF0X:0:0:0:0:0:0:FC | ALL_MPL_FORWARDERS | This | 2013-04-10 | 1036 | | | Document | | 1037 +---------------------+--------------------+-----------+------------+ 1039 Table 3: Variable Scope Multicast Address Allocation 1041 13. Security Considerations 1043 MPL uses sequence numbers to maintain a total ordering of MPL Data 1044 Messages from an MPL Seed. The use of sequence numbers allows a 1045 denial-of-service attack where an attacker can spoof a message with a 1046 sufficiently large sequence number to: (i) flush messages from the 1047 Buffered Message List and (ii) increase the MinSequence value for an 1048 MPL Seed in the corresponding Seed Set. The former side effect 1049 allows an attacker to halt the forwarding process of any MPL Data 1050 Messages being disseminated. The latter side effect allows an 1051 attacker to prevent MPL Forwarders from accepting new MPL Data 1052 Messages that an MPL Seed generates while the sequence number is less 1053 than MinSequence. 1055 More generally, the basic ability to inject messages into a Low-power 1056 and Lossy Network can be used as a denial-of-service attack 1057 regardless of what forwarding protocol is used. For these reasons, 1058 Low-power and Lossy Networks typically employ link-layer security 1059 mechanisms to disable an attacker's ability to inject messages. 1061 To prevent attackers from injecting packets through an MPL Forwarder, 1062 the MPL Forwarder MUST NOT accept or forward MPL Data Messages from a 1063 communication interface that does not subscribe to the MPL Domain 1064 Address identified in message's destination address. 1066 MPL uses the Trickle algorithm to manage message transmissions and 1067 the security considerations described in [RFC6206] apply. 1069 14. References 1071 14.1. Normative References 1073 [I-D.ietf-6man-multicast-scopes] 1074 Droms, R., "IPv6 Multicast Address Scopes", draft-ietf- 1075 6man-multicast-scopes-04 (work in progress), March 2014. 1077 [RFC1982] Elz, R. and R. Bush, "Serial Number Arithmetic", RFC 1982, 1078 August 1996. 1080 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1081 Requirement Levels", BCP 14, RFC 2119, March 1997. 1083 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1084 (IPv6) Specification", RFC 2460, December 1998. 1086 [RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in 1087 IPv6 Specification", RFC 2473, December 1998. 1089 [RFC2780] Bradner, S. and V. Paxson, "IANA Allocation Guidelines For 1090 Values In the Internet Protocol and Related Headers", BCP 1091 37, RFC 2780, March 2000. 1093 [RFC3307] Haberman, B., "Allocation Guidelines for IPv6 Multicast 1094 Addresses", RFC 3307, August 2002. 1096 [RFC4007] Deering, S., Haberman, B., Jinmei, T., Nordmark, E., and 1097 B. Zill, "IPv6 Scoped Address Architecture", RFC 4007, 1098 March 2005. 1100 [RFC4443] Conta, A., Deering, S., and M. Gupta, "Internet Control 1101 Message Protocol (ICMPv6) for the Internet Protocol 1102 Version 6 (IPv6) Specification", RFC 4443, March 2006. 1104 [RFC6206] Levis, P., Clausen, T., Hui, J., Gnawali, O., and J. Ko, 1105 "The Trickle Algorithm", RFC 6206, March 2011. 1107 [RFC6282] Hui, J. and P. Thubert, "Compression Format for IPv6 1108 Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, 1109 September 2011. 1111 [RFC6550] Winter, T., Thubert, P., Brandt, A., Hui, J., Kelsey, R., 1112 Levis, P., Pister, K., Struik, R., Vasseur, JP., and R. 1113 Alexander, "RPL: IPv6 Routing Protocol for Low-Power and 1114 Lossy Networks", RFC 6550, March 2012. 1116 14.2. Informative References 1118 [RFC3973] Adams, A., Nicholas, J., and W. Siadak, "Protocol 1119 Independent Multicast - Dense Mode (PIM-DM): Protocol 1120 Specification (Revised)", RFC 3973, January 2005. 1122 [RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas, 1123 "Protocol Independent Multicast - Sparse Mode (PIM-SM): 1124 Protocol Specification (Revised)", RFC 4601, August 2006. 1126 Authors' Addresses 1128 Jonathan W. Hui 1129 Cisco 1130 170 West Tasman Drive 1131 San Jose, California 95134 1132 USA 1134 Phone: +408 424 1547 1135 Email: jonhui@cisco.com 1136 Richard Kelsey 1137 Silicon Labs 1138 25 Thomson Place 1139 Boston, Massachusetts 02210 1140 USA 1142 Phone: +617 951 1225 1143 Email: richard.kelsey@silabs.com