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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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-13) exists of draft-ietf-6man-rfc2460bis-07 -- Possible downref: Normative reference to a draft: ref. 'I-D.ietf-6man-rfc2460bis' ** Obsolete normative reference: RFC 2460 (Obsoleted by RFC 8200) == Outdated reference: A later version (-30) exists of draft-ietf-6tisch-architecture-10 == Outdated reference: A later version (-05) exists of draft-ietf-roll-routing-dispatch-02 Summary: 1 error (**), 0 flaws (~~), 4 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 ROLL Working Group M. Robles 3 Internet-Draft Ericsson 4 Updates: 6550 (if approved) M. Richardson 5 Intended status: Standards Track SSW 6 Expires: April 24, 2017 P. Thubert 7 Cisco 8 October 21, 2016 10 When to use RFC 6553, 6554 and IPv6-in-IPv6 11 draft-ietf-roll-useofrplinfo-09 13 Abstract 15 This document looks at different data flows through LLN (Low-Power 16 and Lossy Networks) where RPL (IPv6 Routing Protocol for Low-Power 17 and Lossy Networks) is used to establish routing. The document 18 enumerates the cases where RFC 6553, RFC 6554 and IPv6-in-IPv6 19 encapsulation is required. This analysis provides the basis on which 20 to design efficient compression of these headers. 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 April 24, 2017. 39 Copyright Notice 41 Copyright (c) 2016 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 and Requirements Language . . . . . . . . . . . . 3 58 2.1. hop-by-hop IPv6-in-IPv6 headers . . . . . . . . . . . . . 4 59 3. Sample/reference topology . . . . . . . . . . . . . . . . . . 4 60 4. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 7 61 5. Storing mode . . . . . . . . . . . . . . . . . . . . . . . . 9 62 5.1. Example of Flow from RPL-aware-leaf to root . . . . . . . 9 63 5.2. Example of Flow from root to RPL-aware-leaf . . . . . . . 10 64 5.3. Example of Flow from root to not-RPL-aware-leaf . . . . . 11 65 5.4. Example of Flow from not-RPL-aware-leaf to root . . . . . 11 66 5.5. Example of Flow from RPL-aware-leaf to Internet . . . . . 12 67 5.6. Example of Flow from Internet to RPL-aware-leaf . . . . . 12 68 5.7. Example of Flow from not-RPL-aware-leaf to Internet . . . 13 69 5.8. Example of Flow from Internet to non-RPL-aware-leaf . . . 14 70 5.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf . . 15 71 5.10. Example of Flow from RPL-aware-leaf to non-RPL-aware-leaf 16 72 5.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 17 73 5.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware- 74 leaf . . . . . . . . . . . . . . . . . . . . . . . . . . 18 75 6. Non Storing mode . . . . . . . . . . . . . . . . . . . . . . 19 76 6.1. Example of Flow from RPL-aware-leaf to root . . . . . . . 20 77 6.2. Example of Flow from root to RPL-aware-leaf . . . . . . . 20 78 6.3. Example of Flow from root to not-RPL-aware-leaf . . . . . 21 79 6.4. Example of Flow from not-RPL-aware-leaf to root . . . . . 22 80 6.5. Example of Flow from RPL-aware-leaf to Internet . . . . . 23 81 6.6. Example of Flow from Internet to RPL-aware-leaf . . . . . 23 82 6.7. Example of Flow from not-RPL-aware-leaf to Internet . . . 24 83 6.8. Example of Flow from Internet to non-RPL-aware-leaf . . . 25 84 6.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf . . 26 85 6.10. Example of Flow from RPL-aware-leaf to not-RPL-aware-leaf 27 86 6.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 28 87 6.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware- 88 leaf . . . . . . . . . . . . . . . . . . . . . . . . . . 29 89 7. Observations about the cases . . . . . . . . . . . . . . . . 30 90 7.1. Storing mode . . . . . . . . . . . . . . . . . . . . . . 30 91 7.2. Non-Storing mode . . . . . . . . . . . . . . . . . . . . 31 92 8. 6LoRH Compression cases . . . . . . . . . . . . . . . . . . . 31 93 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 31 94 10. Security Considerations . . . . . . . . . . . . . . . . . . . 32 95 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 32 96 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 32 97 12.1. Normative References . . . . . . . . . . . . . . . . . . 32 98 12.2. Informative References . . . . . . . . . . . . . . . . . 33 99 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 34 101 1. Introduction 103 RPL (IPv6 Routing Protocol for Low-Power and Lossy Networks) 104 [RFC6550] is a routing protocol for constrained networks. RFC 6553 105 [RFC6553] defines the "RPL option" (RPI), carried within the IPv6 106 Hop-by-Hop header to quickly identify inconsistencies (loops) in the 107 routing topology. RFC 6554 [RFC6554] defines the "RPL Source Route 108 Header" (RH3), an IPv6 Extension Header to deliver datagrams within a 109 RPL routing domain, particularly in non-storing mode. 111 These various items are referred to as RPL artifacts, and they are 112 seen on all of the data-plane traffic that occurs in RPL routed 113 networks; they do not in general appear on the RPL control plane 114 traffic at all which is mostly hop-by-hop traffic (one exception 115 being DAO messages in non-storing mode). 117 It has become clear from attempts to do multi-vendor 118 interoperability, and from a desire to compress as many of the above 119 artifacts as possible that not all implementors agree when artifacts 120 are necessary, or when they can be safely omitted, or removed. 122 An interim meeting went through the 24 cases defined here to discover 123 if there were any shortcuts, and this document is the result of that 124 discussion. This document should not be defining anything new, but 125 it may clarify what is correct and incorrect behaviour. 127 The related document A Routing Header Dispatch for 6LoWPAN (6LoRH) 128 [I-D.ietf-roll-routing-dispatch] defines a method to compress RPL 129 Option information and Routing Header type 3 [RFC6554], an efficient 130 IP-in-IP technique, and use cases proposed for the 131 [Second6TischPlugtest] involving 6loRH. 133 The related document updates [RFC6550]. In general, any packet that 134 leaves the RPL domain of an LLN (or leaves the LLN entirely) will NOT 135 be discarded, when it has the [RFC6553] RPL Option Header known as 136 the RPI or [RFC6554] SRH3 Extension Header (S)RH3. Due to changes to 137 [I-D.ietf-6man-rfc2460bis] the RPI Hop-by-Hop option MAY be left in 138 place even if the end host does not understand it. 140 2. Terminology and Requirements Language 142 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 143 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 144 document are to be interpreted as described in RFC 2119 [RFC2119]. 146 Terminology defined in [RFC7102] applies to this document: LBR, LLN, 147 RPL, RPL Domain and ROLL. 149 RPL-node: It is device which implements RPL, thus we can say that the 150 device is RPL-capable or RPL-aware. Please note that the device can 151 be found inside the LLN or outside LLN. In this document a RPL-node 152 which is a leaf is called RPL-aware-leaf. 154 RPL-not-capable: It is device which do not implement RPL, thus we can 155 say that the device is not-RPL-aware. Please note that the device 156 can be found inside the LLN. In this document a not-RPL-node which 157 is a leaf is called not-RPL-aware-leaf. 159 2.1. hop-by-hop IPv6-in-IPv6 headers 161 The term "hop-by-hop IPv6-in-IPv6" header refers to: adding a header 162 that originates from a node to an adjacent node, using the addresses 163 (usually the GUA or ULA, but could use the link-local addresses) of 164 each node. If the packet must traverse multiple hops, then it must 165 be decapsulated at each hop, and then re-encapsulated again in a 166 similar fashion. 168 3. Sample/reference topology 170 A RPL network is composed of a 6LBR (6LoWPAN Border Router), Backbone 171 Router (6BBR), 6LR (6LoWPAN Router) and 6LN (6LoWPAN Node) as leaf 172 logically organized in a DODAG structure (Destination Oriented 173 Directed Acyclic Graph). 175 RPL defines the RPL Control messages (control plane), a new ICMPv6 176 [RFC4443] message with Type 155. DIS (DODAG Information 177 Solicitation), DIO (DODAG Information Object) and DAO (Destination 178 Advertisement Object) messages are all RPL Control messages but with 179 different Code values. A RPL Stack is showed in Figure 1. 181 RPL supports two modes of Downward traffic: in storing mode (RPL-SM), 182 it is fully stateful or an in non-storing (RPL-NSM), it is fully 183 source routed. A RPL Instance is either fully storing or fully non- 184 storing, i.e. a RPL Instance with a combination of storing and non- 185 storing nodes is not supported with the current specifications at the 186 time of writing this document. 188 +--------------+ 189 | Upper Layers | 190 | | 191 +--------------+ 192 | RPL | 193 | | 194 +--------------+ 195 | ICMPv6 | 196 | | 197 +--------------+ 198 | IPv6 | 199 | | 200 +--------------+ 201 | 6LoWPAN | 202 | | 203 +--------------+ 204 | PHY-MAC | 205 | | 206 +--------------+ 208 Figure 1: RPL Stack. 210 +---------+ 211 +---+Internet | 212 | +---------+ 213 | 214 +----+--+ 215 | DODAG | node:01 216 +---------+ Root +----------+ 217 | | 6LBR | | 218 | +----+--+ | 219 | | | 220 | | | 221 ... ... ... 222 | | | 223 +-----+-+ +--+---+ +--+---+ 224 |6LR | | | | | 225 +-----+ | | | | | 226 | | 11 | | 12 | | 13 +------+ 227 | +-----+-+ +-+----+ +-+----+ | 228 | | | | | 229 | | | | | 230 | 21 | 22 | 23 | 24 | 25 231 +-+---+ +-+---+ +--+--+ +- --+ +---+-+ 232 |Leaf | | | | | |Leaf| |Leaf | 233 | 6LN | | | | | | 6LN| | 6LN | 234 +-----+ +-----+ +-----+ +----+ +-----+ 236 Figure 2: A reference RPL Topology. 238 In Figure 2 is showed the reference RPL Topology for this document. 239 The numbers in or above the nodes are there so that they may be 240 referenced in subsequent sections. In the figure, a 6LN can be a 241 router or a host. The 6LN leafs marked as (21) is a RPL host that 242 does not have forwarding capability and (25) is a RPL router. The 243 leaf marked 6LN (24) is a device which does not speak RPL at all 244 (not-RPL-aware), but uses Router-Advertisements, 6LowPAN DAR/DAC and 245 efficient-ND only to participate in the network [RFC6775]. In the 246 document this leaf (24) is often named IPv6 node. The 6LBR in the 247 figure is the root of the Global DODAG. 249 This document is in part motivated by the work that is ongoing at the 250 6TiSCH working group. The 6TiSCH architecture 251 [I-D.ietf-6tisch-architecture] draft explains the network 252 architecture of a 6TiSCH network. 254 4. Use cases 256 In data plane context a combination of RFC6553, RFC6554 and IPv6-in- 257 IPv6 encapsulation is going to be analyzed for the following traffic 258 flows. 260 This version of the document assumes the changes in 261 [I-D.ietf-6man-rfc2460bis] are passed (at the time to write this 262 specification, the draft is on version 05). 264 RPL-aware-leaf to root 266 root to RPL-aware-leaf 268 not-RPL-aware-leaf to root 270 root to not-RPL-aware-leaf 272 RPL-aware-leaf to Internet 274 Internet to RPL-aware-leaf 276 not-RPL-aware-leaf to Internet 278 Internet to not-RPL-aware-leaf 280 RPL-aware-leaf to RPL-aware-leaf (storing and non-storing) 282 RPL-aware-leaf to not-RPL-aware-leaf (non-storing) 284 not-RPL-aware-leaf to RPL-aware-leaf (storing and non-storing) 286 not-RPL-aware-leaf to not-RPL-aware-leaf (non-storing) 288 This document assumes the rule that a Header cannot be inserted or 289 removed on the fly inside an IPv6 packet that is being routed. This 290 is a fundamental precept of the IPv6 architecture as outlined in 291 [RFC2460]. Extensions may not be added or removed except by the 292 sender or the receiver. 294 But, options in the Hop-by-Hop option which are marked with option 295 type 01 ([RFC2460] section 4.2 and [I-D.ietf-6man-rfc2460bis]) SHOULD 296 be ignored when received by a host or router which does not 297 understand that option. 299 This means that in general, any packet that leaves the RPL domain of 300 an LLN (or leaves the LLN entirely) will NOT be discarded, when it 301 has the [RFC6553] RPL Option Header known as the RPI or [RFC6554] 302 SRH3 Extension Header (S)RH3. 304 The recent change to the second of these rules it means that the RPI 305 Hop-by-Hop option MAY be left in place even if the end host does not 306 understand it. 308 NOTE: There is some possible security risk when the RPI information 309 is released to the Internet. At this point this is a theoretical 310 situation. It is clear that the RPI option would waste some network 311 bandwidth when it escapes. 313 An intermediate router that needs to add an extension header (SHR3 or 314 RPI Option) must encapsulate the packet in an (additional) outer IP 315 header. The new header can be placed is placed after this new outer 316 IP header. 318 A corollory is that an SHR3 or RPI Option can only be removed by an 319 intermediate router if it is placed in an encapsulating IPv6 Header, 320 which is addressed to the intermediate router. When it does so, the 321 whole encapsulating header must be removed. (A replacement may be 322 added). This sometimes can result in outer IP headers being 323 addressed to the next hop router using link-local addresses. 325 Both RPI and RH3 headers may be modified in very specific ways by 326 routers on the path of the packet without the need to add to remove 327 an encapsulating header. Both headers were designed with this 328 modification in mind, and both the RPL RH and the RPL option are 329 marked mutable but recoverable: so an IPsec AH security header can be 330 applied across these headers, but it can not secure the values which 331 mutate. 333 RPI should be present in every single RPL data packet. There is one 334 exception in non-storing mode: when a packet is going down from the 335 root. In a downward non-storing mode, the entire route is written, 336 so there can be no loops by construction, nor any confusion about 337 which forwarding table to use (as the root has already made all 338 routing decisions). There still may be cases (such as in 6tisch) 339 where the instanceID portion of the RPI header may still be needed to 340 pick an appropriate priority or channel at each hop. 342 In the tables present in this document, the term "RPL aware leaf" is 343 has been shortened to "Raf", and "not-RPL aware leaf" has been 344 shortened to "~Raf" to make the table fit in available space. 346 The earlier examples are more extensive to make sure that the process 347 is clear, while later examples are more consise. 349 5. Storing mode 351 In storing mode (fully stateful), the sender cannot determine whether 352 the destination is RPL-capable and thus would need an IP-in-IP 353 header. The IP-in-IP header needs to be addressed on a hop-by-hop 354 basis so that the last 6LR can remove the RPI header. Additionally, 355 The sender can determine if the destination is inside the LLN by 356 looking if the destination address is matched by the DIO's PIO 357 option. 359 The following table summarizes what headers are needed in the 360 following scenarios, and indicates when the IP-in-IP header must be 361 inserted on a hop-by-hop basis, and when it can target the 362 destination node directly. There are three possible situations: hop- 363 by-hop necessary (indicated by "hop"), or destination address 364 possible (indicated by "dst"). In all cases hop by hop can be used. 365 In cases where no IP-in-IP header is needed, the column is left 366 blank. 368 The leaf can be a router 6LR or a host, both indicated as 6LN. 370 +--------------+-------+-------+-----------+---------------+ 371 | Use Case | RPI | RH3 | IP-in-IP | IP-in-IP dst | 372 +--------------+-------+-------+-----------+---------------+ 373 | Raf to root | Yes | No | No | -- | 374 | root to Raf | Yes | No | No | -- | 375 | root to ~Raf | Yes | No | No | -- | 376 | ~Raf to root | Yes | No | Yes | root | 377 | Raf to Int | Yes | No | No | -- | 378 | Int to Raf | Yes | No | Yes | raf | 379 | ~Raf to Int | Yes | No | Yes | root | 380 | Int to ~Raf | Yes | No | Yes | hop | 381 | Raf to Raf | Yes | No | No | -- | 382 | Raf to ~Raf | Yes | No | No | -- | 383 | ~Raf to Raf | Yes | No | Yes | dst | 384 | ~Raf to ~Raf | Yes | No | Yes | hop | 385 +--------------+-------+-------+-----------+---------------+ 387 Table 1: Headers needed in Storing mode: RPI, RH3, IP-in-IP 388 encapsulation 390 5.1. Example of Flow from RPL-aware-leaf to root 392 In storing mode, RFC 6553 (RPI) is used to send RPL Information 393 instanceID and rank information. 395 As stated in Section 16.2 of [RFC6550] a RPL-aware-leaf node does 396 not generally issue DIO messages; a leaf node accepts DIO messages 397 from upstream. (When the inconsistency in routing occurs, a leaf 398 node will generate a DIO with an infinite rank, to fix it). It may 399 issue DAO and DIS messages though it generally ignores DAO and DIS 400 messages. 402 In this case the flow comprises: 404 RPL-aware-leaf (6LN) --> 6LR1,... --> 6LRN --> root (6LBR) 406 As it was mentioned In this document 6LRs, 6LBR are always full- 407 fledge RPL routers. 409 The 6LN inserts the RPI header, and sends the packet to 6LR which 410 decrements the rank in RPI and sends the packet up. When the packet 411 arrives at 6LBR, the RPI is removed and the packet is processed. 413 No IP-in-IP header is required. 415 The RPI header can be removed by the 6LBR because the packet is 416 addressed to the 6LBR. The 6LN must know that it is communicating 417 with the 6LBR to make use of this scenario. The 6LN can know the 418 address of the 6LBR because it knows the address of the root via the 419 DODAGID in the DIO messages. 421 +-------------------+-----+------+------+ 422 | Header | 6LN | 6LR | 6LBR | 423 +-------------------+-----+------+------+ 424 | Inserted headers | RPI | -- | -- | 425 | Removed headers | -- | -- | RPI | 426 | Re-added headers | -- | -- | -- | 427 | Modified headers | -- | RPI | -- | 428 | Untouched headers | -- | -- | -- | 429 +-------------------+-----+------+------+ 431 Storing: Summary of the use of headers from RPL-aware-leaf to root 433 5.2. Example of Flow from root to RPL-aware-leaf 435 In this case the flow comprises: 437 root (6LBR) --> 6LR1,... --> 6LRN --> RPL-aware-leaf (6LN) 439 In this case the 6LBR inserts RPI header and sends the packet down, 440 the 6LR is going to increment the rank in RPI (examines instanceID 441 for multiple tables), the packet is processed in 6LN and RPI removed. 443 No IP-in-IP header is required. 445 +-------------------+------+-------+------+ 446 | Header | 6LBR | 6LR | 6LN | 447 +-------------------+------+-------+------+ 448 | Inserted headers | RPI | -- | -- | 449 | Removed headers | -- | -- | RPI | 450 | Re-added headers | -- | -- | -- | 451 | Modified headers | -- | RPI | -- | 452 | Untouched headers | -- | -- | -- | 453 +-------------------+------+-------+------+ 455 Storing: Summary of the use of headers from root to RPL-aware-leaf 457 5.3. Example of Flow from root to not-RPL-aware-leaf 459 In this case the flow comprises: 461 root (6LBR) --> 6LR1,... --> 6LRN --> not-RPL-aware-leaf (IPv6) 463 As the RPI extension can be ignored by the not-RPL-aware leaf, this 464 situation is identical to the previous scenario. 466 +-------------------+------+-----------+----------------+ 467 | Header | 6LBR | 6LR(1..N) | 6LN | 468 +-------------------+------+-----------+----------------+ 469 | Inserted headers | RPI | -- | -- | 470 | Removed headers | -- | -- | -- | 471 | Re-added headers | -- | -- | -- | 472 | Modified headers | -- | RPI | -- | 473 | Untouched headers | -- | -- | RPI (Ignored) | 474 +-------------------+------+-----------+----------------+ 476 Storing: Summary of the use of headers from root to not-RPL-aware- 477 leaf 479 5.4. Example of Flow from not-RPL-aware-leaf to root 481 In this case the flow comprises: 483 not-RPL-aware-leaf (IPv6) --> 6LR1,... --> 6LRN --> root (6LBR) 485 When the packet arrives from IPv6 node to 6LR, the 6LR1 will insert 486 an RPI header, encapsuladed in a IPv6-in-IPv6 header. The IPv6-in- 487 IPv6 header can be addressed to the next hop, or to the root. The 488 root removes the header and processes the packet. 490 +------------+------+---------------+---------------+---------------+ 491 | Header | IPv6 | 6LR1 | 6LRN | 6LBR | 492 +------------+------+---------------+---------------+---------------+ 493 | Inserted | -- | IP-in-IP(RPI) | -- | -- | 494 | headers | | | | | 495 | Removed | -- | -- | -- | IP-in-IP(RPI) | 496 | headers | | | | | 497 | Re-added | -- | -- | -- | -- | 498 | headers | | | | | 499 | Modified | -- | -- | IP-in-IP(RPI) | -- | 500 | headers | | | | | 501 | Untouched | -- | -- | -- | -- | 502 | headers | | | | | 503 +------------+------+---------------+---------------+---------------+ 505 Storing: Summary of the use of headers from not-RPL-aware-leaf to 506 root 508 5.5. Example of Flow from RPL-aware-leaf to Internet 510 RPL information from RFC 6553 MAY go out to Internet as it will be 511 ignored by nodes which have not been configured to be RPI aware. 513 In this case the flow comprises: 515 RPL-aware-leaf (6LN) --> 6LR1,... --> 6LRN --> root (6LBR) --> 516 Internet 518 No IP-in-IP header is required. 520 +-------------------+------+-----------+------+----------------+ 521 | Header | 6LN | 6LR(1..N) | 6LBR | Internet | 522 +-------------------+------+-----------+------+----------------+ 523 | Inserted headers | RPI | -- | -- | -- | 524 | Removed headers | -- | -- | -- | -- | 525 | Re-added headers | -- | -- | -- | -- | 526 | Modified headers | -- | RPI | -- | -- | 527 | Untouched headers | -- | -- | -- | RPI (Ignored) | 528 +-------------------+------+-----------+------+----------------+ 530 Storing: Summary of the use of headers from RPL-aware-leaf to 531 Internet 533 5.6. Example of Flow from Internet to RPL-aware-leaf 535 In this case the flow comprises: 537 Internet --> root (6LBR) --> 6LR1,... --> 6LRN --> RPL-aware-leaf 538 (6LN) 540 When the packet arrives from Internet to 6LBR the RPI header is added 541 in a outer IPv6-in-IPv6 header and sent to 6LR, which modifies the 542 rank in the RPI. When the packet arrives at 6LN the RPI header is 543 removed and the packet processed. 545 +----------+---------+--------------+---------------+---------------+ 546 | Header | Interne | 6LBR | 6LR(1...N) | 6LN | 547 | | t | | | | 548 +----------+---------+--------------+---------------+---------------+ 549 | Inserted | -- | IP-in- | -- | -- | 550 | headers | | IP(RPI) | | | 551 | Removed | -- | -- | -- | IP-in-IP(RPI) | 552 | headers | | | | | 553 | Re-added | -- | -- | -- | -- | 554 | headers | | | | | 555 | Modified | -- | -- | IP-in-IP(RPI) | -- | 556 | headers | | | | | 557 | Untouche | -- | -- | -- | -- | 558 | d | | | | | 559 | headers | | | | | 560 +----------+---------+--------------+---------------+---------------+ 562 Storing: Summary of the use of headers from Internet to RPL-aware- 563 leaf 565 5.7. Example of Flow from not-RPL-aware-leaf to Internet 567 In this case the flow comprises: 569 not-RPL-aware-leaf (IPv6) --> 6LR1,... --> 6LRN --> root (6LBR) --> 570 Internet 572 The 6LR1 node will add an IP-in-IP(RPI) header addressed either to 573 the root, or hop-by-hop such that the root can remove the RPI header 574 before passing upwards. 576 The originating node will ideally leave the IPv6 flow label as zero 577 so that it can be better compressed through the LLN, and the 6LBR 578 will set the flow label to a non-zero value when sending to the 579 Internet. 581 +---------+-----+-------------+-------------+-------------+---------+ 582 | Header | IPv | 6LR1 | 6LBN | 6LBR | Interne | 583 | | 6 | | | | t | 584 +---------+-----+-------------+-------------+-------------+---------+ 585 | Inserte | -- | IP-in- | -- | -- | -- | 586 | d | | IP(RPI) | | | | 587 | headers | | | | | | 588 | Removed | -- | -- | -- | IP-in- | -- | 589 | headers | | | | IP(RPI) | | 590 | Re- | -- | -- | -- | -- | -- | 591 | added | | | | | | 592 | headers | | | | | | 593 | Modifie | -- | -- | IP-in- | -- | -- | 594 | d | | | IP(RPI) | | | 595 | headers | | | | | | 596 | Untouch | -- | -- | -- | -- | -- | 597 | ed | | | | | | 598 | headers | | | | | | 599 +---------+-----+-------------+-------------+-------------+---------+ 601 Storing: Summary of the use of headers from not-RPL-aware-leaf to 602 Internet 604 5.8. Example of Flow from Internet to non-RPL-aware-leaf 606 In this case the flow comprises: 608 Internet --> root (6LBR) --> 6LR1,... --> 6LRN --> not-RPL-aware-leaf 609 (IPv6) 611 The 6LBR will have to add an RPI header within an IP-in-IP header. 612 The IP-in-IP can be addressed to the not-RPL-aware-leaf, leaving the 613 RPI inside. 615 The 6LBR MAY set the flow label on the inner IP-in-IP header to zero 616 in order to aid in compression, as the packet will not emerge again 617 from the LLN. 619 +-----------+----------+---------------+---------------+------------+ 620 | Header | Internet | 6LBR | 6LR(1...N) | IPv6 | 621 +-----------+----------+---------------+---------------+------------+ 622 | Inserted | -- | IP-in-IP(RPI) | -- | -- | 623 | headers | | | | | 624 | Removed | -- | -- | IP-in-IP(RPI) | -- | 625 | headers | | | | | 626 | Re-added | -- | -- | -- | -- | 627 | headers | | | | | 628 | Modified | -- | -- | IP-in-IP(RPI) | -- | 629 | headers | | | | | 630 | Untouched | -- | -- | -- | RPI | 631 | headers | | | | (Ignored) | 632 +-----------+----------+---------------+---------------+------------+ 634 Storing: Summary of the use of headers from Internet to non-RPL- 635 aware-leaf 637 5.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf 639 In [RFC6550] RPL allows a simple one-hop optimization for both 640 storing and non-storing networks. A node may send a packet destined 641 to a one-hop neighbor directly to that node. Section 9 in [RFC6550]. 643 In this case the flow comprises: 645 6LN --> 6LR1 --> common parent (6LRx) --> 6LRN --> 6LN 647 This case is assumed in the same RPL Domain. In the common parent, 648 the direction of RPI is changed (from increasing to decreasing the 649 rank). 651 While the 6LR nodes will update the RPI, no node needs to add or 652 remove the RPI, so no IP-in-IP headers are necessary. This may be 653 done regardless of where the destination is, as the included RPI will 654 be ignored by the receiver. 656 +------------+-------+---------------+---------------+------+-------+ 657 | Header | 6LN | 6LR1 | 6LRx (common | 6LRN | 6LN | 658 | | src | | parent) | | dst | 659 +------------+-------+---------------+---------------+------+-------+ 660 | Inserted | RPI | -- | -- | -- | -- | 661 | headers | | | | | | 662 | Removed | -- | -- | -- | -- | RPI | 663 | headers | | | | | | 664 | Re-added | -- | -- | -- | -- | -- | 665 | headers | | | | | | 666 | Modified | -- | RPI | RPI | -- | -- | 667 | headers | | (decreasing | (increasing | | | 668 | | | rank) | rank) | | | 669 | Untouched | -- | -- | -- | -- | -- | 670 | headers | | | | | | 671 +------------+-------+---------------+---------------+------+-------+ 673 Storing: Summary of the use of headers for RPL-aware-leaf to RPL- 674 aware-leaf 676 5.10. Example of Flow from RPL-aware-leaf to non-RPL-aware-leaf 678 In this case the flow comprises: 680 6LN --> 6LR1 --> common parent (6LRx) --> 6LRN --> not-RPL-aware 6LN 681 (IPv6) 683 This situation is identical to the previous situation Section 5.9 684 +-----------+-----+-------------+-------------+------+--------------+ 685 | Header | 6LN | 6LR1 | 6LRx | 6LRN | IPv6 | 686 | | src | | (common | | | 687 | | | | parent) | | | 688 +-----------+-----+-------------+-------------+------+--------------+ 689 | Inserted | RPI | -- | -- | -- | -- | 690 | headers | | | | | | 691 | Removed | -- | -- | -- | -- | RPI | 692 | headers | | | | | | 693 | Re-added | -- | -- | -- | -- | -- | 694 | headers | | | | | | 695 | Modified | -- | RPI | RPI | -- | -- | 696 | headers | | (decreasing | (increasing | | | 697 | | | rank) | rank) | | | 698 | Untouched | -- | -- | -- | -- | RPI(Ignored) | 699 | headers | | | | | | 700 +-----------+-----+-------------+-------------+------+--------------+ 702 Storing: Summary of the use of headers for RPL-aware-leaf to RPL- 703 aware-leaf 705 5.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 707 In this case the flow comprises: 709 not-RPL-aware 6LN (IPv6) --> 6LR1 --> common parent (6LRx) --> 6LRN 710 --> 6LN 712 The 6LR1 receives the packet from the the IPv6 node and inserts and 713 the RPI header encapsulated in IPv6-in-IPv6 header. The IP-in-IP 714 header is addressed to the destination 6LN. 716 +--------+------+------------+------------+------------+------------+ 717 | Header | IPv6 | 6LR1 | common | 6LRn | 6LN | 718 | | | | parent | | | 719 | | | | (6LRx) | | | 720 +--------+------+------------+------------+------------+------------+ 721 | Insert | -- | IP-in- | -- | -- | -- | 722 | ed hea | | IP(RPI) | | | | 723 | ders | | | | | | 724 | Remove | -- | -- | -- | -- | IP-in- | 725 | d head | | | | | IP(RPI) | 726 | ers | | | | | | 727 | Re- | -- | -- | -- | -- | -- | 728 | added | | | | | | 729 | header | | | | | | 730 | s | | | | | | 731 | Modifi | -- | -- | IP-in- | IP-in- | -- | 732 | ed hea | | | IP(RPI) | IP(RPI) | | 733 | ders | | | | | | 734 | Untouc | -- | -- | -- | -- | -- | 735 | hed he | | | | | | 736 | aders | | | | | | 737 +--------+------+------------+------------+------------+------------+ 739 Storing: Summary of the use of headers from not-RPL-aware-leaf to 740 RPL-aware-leaf 742 5.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-leaf 744 In this case the flow comprises: 746 not-RPL-aware 6LN (IPv6 src)--> 6LR1 --> 6LR2 --> root (6LBR) --> 747 6LRn --> not-RPL-aware 6LN (IPv6 dst) 749 This flow is identical to Section 5.11 751 The 6LR receives the packet from the the IPv6 node and inserts the 752 RPI header (RPIa) encapsulated in IPv6-in-IPv6 header. The IPv6-in- 753 IPv6 header is addressed to the 6LBR. The 6LBR remove the IPv6-in- 754 IPv6 header and insert another one (RPIb) with destination to 6LRn 755 node. 757 +-------+-----+-----------+-----------+-----------+-----------+-----+ 758 | Heade | IPv | 6LR1 | 6LR2 | 6LBR | 6LRn | IPv | 759 | r | 6 | | | | | 6 | 760 | | src | | | | | dst | 761 +-------+-----+-----------+-----------+-----------+-----------+-----+ 762 | Inser | -- | IP-in- | -- | IP-in- | -- | -- | 763 | ted h | | IP(RPIa) | | IP(RPIb) | | | 764 | eader | | | | | | | 765 | s | | | | | | | 766 | Remov | -- | -- | -- | -- | -- | -- | 767 | ed he | | | | | | | 768 | aders | | | | | | | 769 | Re- | -- | -- | -- | -- | IP-in- | -- | 770 | added | | | | | IP(RPIb) | | 771 | heade | | | | | | | 772 | rs | | | | | | | 773 | Modif | -- | -- | IP-in- | -- | IP-in- | -- | 774 | ied h | | | IP(RPIa) | | IP(RPIb) | | 775 | eader | | | | | | | 776 | s | | | | | | | 777 | Untou | -- | -- | -- | -- | -- | -- | 778 | ched | | | | | | | 779 | heade | | | | | | | 780 | rs | | | | | | | 781 +-------+-----+-----------+-----------+-----------+-----------+-----+ 783 Storing: Summary of the use of headers from not-RPL-aware-leaf to 784 non-RPL-aware-leaf 786 6. Non Storing mode 787 +--------------+------+------+-----------+---------------+ 788 | Use Case | RPI | RH3 | IP-in-IP | IP-in-IP dst | 789 +--------------+------+------+-----------+---------------+ 790 | Raf to root | Yes | No | No | -- | 791 | root to Raf | Opt | Yes | No | -- | 792 | root to ~Raf | No | Yes | Yes | 6LR | 793 | ~Raf to root | Yes | No | Yes | root | 794 | Raf to Int | Yes | No | Yes | root | 795 | Int to Raf | Opt | Yes | Yes | dst | 796 | ~Raf to Int | Yes | No | Yes | root | 797 | Int to ~Raf | Opt | Yes | Yes | 6LR | 798 | Raf to Raf | Yes | Yes | Yes | root/dst | 799 | Raf to ~Raf | Yes | Yes | Yes | root/6LR | 800 | ~Raf to Raf | Yes | Yes | Yes | root/6LN | 801 | ~Raf to ~Raf | Yes | Yes | Yes | root/6LR | 802 +--------------+------+------+-----------+---------------+ 804 Table 2: Headers needed in Non-Storing mode: RPI, RH3, IP-in-IP 805 encapsulation 807 6.1. Example of Flow from RPL-aware-leaf to root 809 In non-storing mode the leaf node uses default routing to send 810 traffic to the root. The RPI header must be included to avoid/detect 811 loops. 813 RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) 815 This situation is the same case as storing mode. 817 +-------------------+-----+------+------+ 818 | Header | 6LN | 6LR | 6LBR | 819 +-------------------+-----+------+------+ 820 | Inserted headers | RPI | -- | -- | 821 | Removed headers | -- | -- | RPI | 822 | Re-added headers | -- | -- | -- | 823 | Modified headers | -- | RPI | -- | 824 | Untouched headers | -- | -- | -- | 825 +-------------------+-----+------+------+ 827 Non Storing: Summary of the use of headers from RPL-aware-leaf to 828 root 830 6.2. Example of Flow from root to RPL-aware-leaf 832 In this case the flow comprises: 834 root (6LBR)--> 6LR --> RPL-aware-leaf (6LN) 835 The 6LBR will insert an RH3, and may optionally insert an RPI header. 836 No IP-in-IP header is necessary as the traffic originates with an RPL 837 aware node, the 6LBR. The destination is known to RPL-aware because, 838 the root knows the whole topology in non-storing mode. 840 +-------------------+-----------------+------+----------+ 841 | Header | 6LBR | 6LR | 6LN | 842 +-------------------+-----------------+------+----------+ 843 | Inserted headers | (opt: RPI), RH3 | -- | -- | 844 | Removed headers | -- | -- | RH3,RPI | 845 | Re-added headers | -- | -- | -- | 846 | Modified headers | -- | RH3 | -- | 847 | Untouched headers | -- | -- | -- | 848 +-------------------+-----------------+------+----------+ 850 Non Storing: Summary of the use of headers from root to RPL-aware- 851 leaf 853 6.3. Example of Flow from root to not-RPL-aware-leaf 855 In this case the flow comprises: 857 root (6LBR)--> 6LR1...-->6LRn --> not-RPL-aware-leaf (IPv6) 859 In 6LBR the RH3 is added, modified in each intermediate 6LR (6LR1 and 860 so on) and it is fully consumed in the last 6LR (6LRn), but left 861 there. If RPI is left present, the IPv6 node which does not 862 understand it will ignore it (following 2460bis), thus encapsulation 863 is not necesary. Due the complete knowledge of the topology at the 864 root, the 6LBR is able to address the IP-in-IP header to the last 865 6LR. 867 +----------------+--------------+--------------+-------------+------+ 868 | Header | 6LBR | 6LR1 | 6LRn | IPv6 | 869 +----------------+--------------+--------------+-------------+------+ 870 | Inserted | (opt: RPI), | -- | -- | -- | 871 | headers | RH3 | | | | 872 | Removed | -- | RH3 | -- | -- | 873 | headers | | | | | 874 | Re-added | -- | -- | -- | -- | 875 | headers | | | | | 876 | Modified | -- | (opt: RPI), | (opt: RPI), | -- | 877 | headers | | RH3 | RH3 | | 878 | Untouched | -- | -- | -- | RPI | 879 | headers | | | | | 880 +----------------+--------------+--------------+-------------+------+ 882 Non Storing: Summary of the use of headers from root to not-RPL- 883 aware-leaf 885 6.4. Example of Flow from not-RPL-aware-leaf to root 887 In this case the flow comprises: 889 IPv6-node --> 6LR1 ...--> 6LRn --> root (6LBR) 891 In this case the RPI is added by the first 6LR (6LR1), encapsulated 892 in an IP-in-IP header, and is modified in the followings 6LRs. The 893 RPI and entire packet is consumed by the root. 895 +------------+------+---------------+---------------+---------------+ 896 | Header | IPv6 | 6LR1 | 6LR2 | 6LBR | 897 +------------+------+---------------+---------------+---------------+ 898 | Inserted | -- | IP-in-IP(RPI) | -- | -- | 899 | headers | | | | | 900 | Removed | -- | -- | -- | IP-in-IP(RPI) | 901 | headers | | | | | 902 | Re-added | -- | -- | -- | -- | 903 | headers | | | | | 904 | Modified | -- | IP-in-IP(RPI) | IP-in-IP(RPI) | -- | 905 | headers | | | | | 906 | Untouched | -- | -- | -- | -- | 907 | headers | | | | | 908 +------------+------+---------------+---------------+---------------+ 910 Non Storing: Summary of the use of headers from not-RPL-aware-leaf to 911 root 913 6.5. Example of Flow from RPL-aware-leaf to Internet 915 In this case the flow comprises: 917 RPL-aware-leaf (6LN) --> 6LR1 ...--> 6LRn --> root (6LBR) --> 918 Internet 920 This case is identical to storing-mode case. 922 The IPv6 flow label should be set to zero to aid in compression, and 923 the 6LBR will set it to a non-zero value when sending towards the 924 Internet. 926 +-------------------+------+-----------+------+----------------+ 927 | Header | 6LN | 6LR(1..N) | 6LBR | Internet | 928 +-------------------+------+-----------+------+----------------+ 929 | Inserted headers | RPI | -- | -- | -- | 930 | Removed headers | -- | -- | -- | -- | 931 | Re-added headers | -- | -- | -- | -- | 932 | Modified headers | -- | RPI | -- | -- | 933 | Untouched headers | -- | -- | -- | RPI (Ignored) | 934 +-------------------+------+-----------+------+----------------+ 936 Non Storing: Summary of the use of headers from RPL-aware-leaf to 937 Internet 939 6.6. Example of Flow from Internet to RPL-aware-leaf 941 In this case the flow comprises: 943 Internet --> root (6LBR) --> 6LR1...--> 6LRn --> RPL-aware-leaf (6LN) 945 The 6LBR must add an RH3 header. As the 6LBR will know the path and 946 address of the target node, it can address the IP-in-IP header to 947 that node. The 6LBR will zero the flow label upon entry in order to 948 aid compression. 950 The RPI may be added or not, it is optional. 952 +--------+-------+----------------+----------------+----------------+ 953 | Header | Inter | 6LBR | 6LR | 6LN | 954 | | net | | | | 955 +--------+-------+----------------+----------------+----------------+ 956 | Insert | -- | IP-in-IP(RH3,o | -- | -- | 957 | ed hea | | pt:RPI) | | | 958 | ders | | | | | 959 | Remove | -- | -- | -- | IP-in-IP(RH3,o | 960 | d head | | | | pt:RPI) | 961 | ers | | | | | 962 | Re- | -- | -- | -- | -- | 963 | added | | | | | 964 | header | | | | | 965 | s | | | | | 966 | Modifi | -- | -- | IP-in-IP(RH3,o | -- | 967 | ed hea | | | pt:RPI) | | 968 | ders | | | | | 969 | Untouc | -- | -- | -- | -- | 970 | hed he | | | | | 971 | aders | | | | | 972 +--------+-------+----------------+----------------+----------------+ 974 Non Storing: Summary of the use of headers from Internet to RPL- 975 aware-leaf 977 6.7. Example of Flow from not-RPL-aware-leaf to Internet 979 In this case the flow comprises: 981 not-RPL-aware-leaf (IPv6) --> 6LR1..--> 6LRn --> root (6LBR) --> 982 Internet 984 In this case the flow label is recommended to be zero in the IPv6 985 node. As RPL headers are added in the IPv6 node, the first 6LN will 986 add an RPI header inside a new IP-in-IP header. The IP-in-IP header 987 will be addressed to the root. This case is identical to the 988 storing-mode case (Section 5.7). 990 +---------+-----+-------------+-------------+-------------+---------+ 991 | Header | IPv | 6LR1 | 6LRn | 6LBR | Interne | 992 | | 6 | | | | t | 993 +---------+-----+-------------+-------------+-------------+---------+ 994 | Inserte | -- | IP-in- | -- | -- | -- | 995 | d | | IP(RPI) | | | | 996 | headers | | | | | | 997 | Removed | -- | -- | -- | IP-in- | -- | 998 | headers | | | | IP(RPI) | | 999 | Re- | -- | -- | -- | -- | -- | 1000 | added | | | | | | 1001 | headers | | | | | | 1002 | Modifie | -- | -- | IP-in- | -- | -- | 1003 | d | | | IP(RPI) | | | 1004 | headers | | | | | | 1005 | Untouch | -- | -- | -- | -- | -- | 1006 | ed | | | | | | 1007 | headers | | | | | | 1008 +---------+-----+-------------+-------------+-------------+---------+ 1010 Non Storing: Summary of the use of headers from not-RPL-aware-leaf to 1011 Internet 1013 6.8. Example of Flow from Internet to non-RPL-aware-leaf 1015 In this case the flow comprises: 1017 Internet --> root (6LBR) --> 6LR1...--> 6LRn --> not-RPL-aware-leaf 1018 (IPv6) 1020 The 6LBR must add an RH3 header inside an IP-in-IP header. The 6LBR 1021 will know the path, and will recognize that the final node is not an 1022 RPL capable node as it will have received the connectivity DAO from 1023 the nearest 6LR. The 6LBR can therefore make the IP-in-IP header 1024 destination be the last 6LR. The 6LBR will set to zero the flow 1025 label upon entry in order to aid compression. 1027 +--------+-------+-----------------+------------+------------+------+ 1028 | Header | Inter | 6LBR | 6LR1 | 6LRn | IPv6 | 1029 | | net | | | | | 1030 +--------+-------+-----------------+------------+------------+------+ 1031 | Insert | -- | IP-in- | -- | -- | -- | 1032 | ed hea | | IP(RH3,opt:RPI) | | | | 1033 | ders | | | | | | 1034 | Remove | -- | -- | -- | IP-in- | -- | 1035 | d head | | | | IP(RH3, | | 1036 | ers | | | | RPI) | | 1037 | Re- | -- | -- | -- | -- | -- | 1038 | added | | | | | | 1039 | header | | | | | | 1040 | s | | | | | | 1041 | Modifi | -- | -- | IP-in- | IP-in- | -- | 1042 | ed hea | | | IP(RH3, | IP(RH3, | | 1043 | ders | | | RPI) | RPI) | | 1044 | Untouc | -- | -- | -- | -- | RPI | 1045 | hed he | | | | | | 1046 | aders | | | | | | 1047 +--------+-------+-----------------+------------+------------+------+ 1049 NonStoring: Summary of the use of headers from Internet to non-RPL- 1050 aware-leaf 1052 6.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf 1054 In this case the flow comprises: 1056 6LN --> 6LR1 --> root (6LBR) --> 6LRN --> 6LN 1058 This case involves only nodes in same RPL Domain. The originating 1059 node will add an RPI header to the original packet, and send the 1060 packet upwards. 1062 The originating node SHOULD put the RPI into an IP-in-IP header 1063 addressed to the root, so that the 6LBR can remove that header. If 1064 it does not, then additional resources are wasted on the way down to 1065 carry the useless RPI option. 1067 The 6LBR will need to insert an RH3 header, which requires that it 1068 add an IP-in-IP header. It SHOULD be able to remove the RPI, as it 1069 was contained in an IP-in-IP header addressed to it. Otherwise, 1070 there MAY be an RPI header buried inside the inner IP header, which 1071 should get ignored. 1073 Networks that use the RPL P2P extension [RFC6997] are essentially 1074 non-storing DODAGs and fall into this scenario or scenario 1075 Section 6.2, with the originating node acting as 6LBR. 1077 +---------+-------------+------+--------------+------+--------------+ 1078 | Header | 6LN src | 6LR1 | 6LBR | 6LRN | 6LN dst | 1079 +---------+-------------+------+--------------+------+--------------+ 1080 | Inserte | IP-in- | -- | IP-in-IP(RH3 | -- | -- | 1081 | d | IP(RPI1) | | to 6LN, opt | | | 1082 | headers | | | RPI2) | | | 1083 | Removed | -- | -- | IP-in- | -- | IP-in- | 1084 | headers | | | IP(RPI1) | | IP(RH3, opt | 1085 | | | | | | RPI2) | 1086 | Re- | -- | -- | -- | -- | -- | 1087 | added | | | | | | 1088 | headers | | | | | | 1089 | Modifie | -- | -- | -- | -- | -- | 1090 | d | | | | | | 1091 | headers | | | | | | 1092 | Untouch | -- | -- | -- | -- | -- | 1093 | ed | | | | | | 1094 | headers | | | | | | 1095 +---------+-------------+------+--------------+------+--------------+ 1097 Non Storing: Summary of the use of headers for RPL-aware-leaf to RPL- 1098 aware-leaf 1100 6.10. Example of Flow from RPL-aware-leaf to not-RPL-aware-leaf 1102 In this case the flow comprises: 1104 6LN --> 6LR1 --> root (6LBR) --> 6LRn --> not-RPL-aware (IPv6) 1106 As in the previous case, the 6LN will insert an RPI (RPI1) header 1107 which MUST be in an IP-in-IP header addressed to the root so that the 1108 6LBR can remove this RPI. The 6LBR will then insert an RH3 inside a 1109 new IP-in-IP header addressed to the 6LN destination node. The RPI 1110 is optional from 6LBR to 6LRn (RPI2). 1112 +--------+------------+------------+------------+------------+------+ 1113 | Header | 6LN | 6LR1 | 6LBR | 6LRn | IPv6 | 1114 +--------+------------+------------+------------+------------+------+ 1115 | Insert | IP-in- | -- | IP-in- | -- | -- | 1116 | ed hea | IP(RPI1) | | IP(RH3, | | | 1117 | ders | | | opt RPI2) | | | 1118 | Remove | -- | -- | IP-in- | IP-in- | -- | 1119 | d head | | | IP(RPI1) | IP(RH3, | | 1120 | ers | | | | opt RPI2) | | 1121 | Re- | -- | -- | -- | -- | -- | 1122 | added | | | | | | 1123 | header | | | | | | 1124 | s | | | | | | 1125 | Modifi | -- | IP-in- | -- | IP-in- | -- | 1126 | ed hea | | IP(RPI1) | | IP(RH3, | | 1127 | ders | | | | opt RPI2) | | 1128 | Untouc | -- | -- | -- | -- | opt | 1129 | hed he | | | | | RPI2 | 1130 | aders | | | | | | 1131 +--------+------------+------------+------------+------------+------+ 1133 Non Storing: Summary of the use of headers from RPL-aware-leaf to 1134 not-RPL-aware-leaf 1136 6.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 1138 In this case the flow comprises: 1140 not-RPL-aware 6LN (IPv6) --> 6LR1 --> root (6LBR) --> 6LRn --> 6LN 1142 This scenario is mostly identical to the previous one. The RPI is 1143 added by the first 6LR (6LR1) inside an IP-in-IP header addressed to 1144 the root. The 6LBR will remove this RPI, and add it's own IP-in-IP 1145 header containing an RH3 header and optional RPI (RPI2). 1147 +--------+-----+------------+-------------+------------+------------+ 1148 | Header | IPv | 6LR1 | 6LBR | 6LRn | 6LN | 1149 | | 6 | | | | | 1150 +--------+-----+------------+-------------+------------+------------+ 1151 | Insert | -- | IP-in- | IP-in- | -- | -- | 1152 | ed hea | | IP(RPI1) | IP(RH3, opt | | | 1153 | ders | | | RPI2) | | | 1154 | Remove | -- | -- | IP-in- | -- | IP-in- | 1155 | d head | | | IP(RPI1) | | IP(RH3, | 1156 | ers | | | | | opt RPI2) | 1157 | Re- | -- | -- | -- | -- | -- | 1158 | added | | | | | | 1159 | header | | | | | | 1160 | s | | | | | | 1161 | Modifi | -- | -- | -- | IP-in- | -- | 1162 | ed hea | | | | IP(RH3, | | 1163 | ders | | | | opt RPI2) | | 1164 | Untouc | -- | -- | -- | -- | -- | 1165 | hed he | | | | | | 1166 | aders | | | | | | 1167 +--------+-----+------------+-------------+------------+------------+ 1169 Non Storing: Summary of the use of headers from not-RPL-aware-leaf to 1170 RPL-aware-leaf 1172 6.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-leaf 1174 In this case the flow comprises: 1176 not-RPL-aware 6LN (IPv6 src)--> 6LR1 --> root (6LBR) --> 6LRn --> 1177 not-RPL-aware (IPv6 dst) 1179 This scenario is the combination of the previous two cases. 1181 +---------+-----+--------------+--------------+--------------+------+ 1182 | Header | IPv | 6LR1 | 6LBR | 6LRn | IPv6 | 1183 | | 6 | | | | dst | 1184 | | src | | | | | 1185 +---------+-----+--------------+--------------+--------------+------+ 1186 | Inserte | -- | IP-in- | IP-in- | -- | -- | 1187 | d | | IP(RPI1) | IP(RH3) | | | 1188 | headers | | | | | | 1189 | Removed | -- | -- | IP-in- | IP-in- | -- | 1190 | headers | | | IP(RPI1) | IP(RH3, opt | | 1191 | | | | | RPI2) | | 1192 | Re- | -- | -- | -- | -- | -- | 1193 | added | | | | | | 1194 | headers | | | | | | 1195 | Modifie | -- | -- | -- | -- | -- | 1196 | d | | | | | | 1197 | headers | | | | | | 1198 | Untouch | -- | -- | -- | -- | -- | 1199 | ed | | | | | | 1200 | headers | | | | | | 1201 +---------+-----+--------------+--------------+--------------+------+ 1203 Non Storing: Summary of the use of headers from not-RPL-aware-leaf to 1204 not-RPL-aware-leaf 1206 7. Observations about the cases 1208 7.1. Storing mode 1210 [I-D.ietf-roll-routing-dispatch] shows that this hop-by-hop IP-in-IP 1211 header can be compressed down to {TBD} bytes. 1213 There are potential significant advantages to having a single code 1214 path that always processes IP-in-IP headers with no options. 1216 Thanks to the relaxation of the RFC2406 rule about discarding unknown 1217 Hop-by-Hop options, there is no longer any uncertainty about when to 1218 use an IPIP header in the storing mode case. The RPI header SHOULD 1219 always be added when 6LRs originate packets (without IPIP headers), 1220 and IPIP headers should always be added (addressed to the root when 1221 on the way up, to the end-host when on the way down) when a 6LR finds 1222 it needs to insert an RPI header. (XXX - this is a problem for 1223 storing mode optimization) 1225 In order to support the above two cases with full generality, the 1226 different situations (always do IP-in-IP vs never use IP-in-IP) 1227 should be signaled in the RPL protocol itself. 1229 7.2. Non-Storing mode 1231 In the non-storing case, dealing with non-RPL aware leaf nodes is 1232 much easier as the 6LBR (DODAG root) has complete knowledge about the 1233 connectivity of all DODAG nodes, and all traffic flows through the 1234 root node. 1236 The 6LBR can recognize non-RPL aware leaf nodes because it will 1237 receive a DAO about that node from the 6LN immediately above that 1238 node. This means that the non-storing mode case can avoid ever using 1239 hop-by-hop IP-in-IP headers. 1241 [I-D.ietf-roll-routing-dispatch] shows how the destination=root, and 1242 destination=6LN IP-in-IP header can be compressed down to {TBD} 1243 bytes. 1245 Unlike in the storing mode case, there is no need for all nodes to 1246 know about the existence of non-RPL aware nodes. Only the 6LBR needs 1247 to change when there are non-RPL aware nodes. Further, in the non- 1248 storing case, the 6LBR is informed by the DAOs when there are non-RPL 1249 aware nodes. 1251 8. 6LoRH Compression cases 1253 The [I-D.ietf-roll-routing-dispatch] proposes a compression method 1254 for RPI, RH3 and IPv6-in-IPv6. 1256 In Storing Mode, for the examples of Flow from RPL-aware-leaf to non- 1257 RPL-aware-leaf and non-RPL-aware-leaf to non-RPL-aware-leaf comprise 1258 an IP-in-IP and RPI compression headers. The type of this case is 1259 critical since IP-in-IP is encapsulating a RPI header. 1261 +--+-----+---+--------------+-----------+-------------+-------------+ 1262 |1 | 0|0 |TSE| 6LoRH Type 6 | Hop Limit | RPI - 6LoRH | LOWPAN IPHC | 1263 +--+-----+---+--------------+-----------+-------------+-------------+ 1265 Figure 3: Critical IP-in-IP (RPI). 1267 9. IANA Considerations 1269 There are no IANA considerations related to this document. 1271 10. Security Considerations 1273 The security considerations covering of [RFC6553] and [RFC6554] apply 1274 when the packets get into RPL Domain. 1276 11. Acknowledgments 1278 This work is partially funded by the FP7 Marie Curie Initial Training 1279 Network (ITN) METRICS project (grant agreement No. 607728). 1281 The authors would like to acknowledge the review, feedback, and 1282 comments of Robert Cragie, Simon Duquennoy, Cenk Guendogan, Peter van 1283 der Stok, Xavier Vilajosana and Thomas Watteyne. 1285 12. References 1287 12.1. Normative References 1289 [I-D.ietf-6man-rfc2460bis] 1290 Deering, S. and R. Hinden, "Internet Protocol, Version 6 1291 (IPv6) Specification", draft-ietf-6man-rfc2460bis-07 (work 1292 in progress), October 2016. 1294 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1295 Requirement Levels", BCP 14, RFC 2119, 1296 DOI 10.17487/RFC2119, March 1997, 1297 . 1299 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1300 (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460, 1301 December 1998, . 1303 [RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J., 1304 Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur, 1305 JP., and R. Alexander, "RPL: IPv6 Routing Protocol for 1306 Low-Power and Lossy Networks", RFC 6550, 1307 DOI 10.17487/RFC6550, March 2012, 1308 . 1310 [RFC6553] Hui, J. and JP. Vasseur, "The Routing Protocol for Low- 1311 Power and Lossy Networks (RPL) Option for Carrying RPL 1312 Information in Data-Plane Datagrams", RFC 6553, 1313 DOI 10.17487/RFC6553, March 2012, 1314 . 1316 [RFC6554] Hui, J., Vasseur, JP., Culler, D., and V. Manral, "An IPv6 1317 Routing Header for Source Routes with the Routing Protocol 1318 for Low-Power and Lossy Networks (RPL)", RFC 6554, 1319 DOI 10.17487/RFC6554, March 2012, 1320 . 1322 12.2. Informative References 1324 [I-D.ietf-6tisch-architecture] 1325 Thubert, P., "An Architecture for IPv6 over the TSCH mode 1326 of IEEE 802.15.4", draft-ietf-6tisch-architecture-10 (work 1327 in progress), June 2016. 1329 [I-D.ietf-roll-routing-dispatch] 1330 Thubert, P., Bormann, C., Toutain, L., and R. Cragie, 1331 "6LoWPAN Routing Header", draft-ietf-roll-routing- 1332 dispatch-02 (work in progress), October 2016. 1334 [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet 1335 Control Message Protocol (ICMPv6) for the Internet 1336 Protocol Version 6 (IPv6) Specification", RFC 4443, 1337 DOI 10.17487/RFC4443, March 2006, 1338 . 1340 [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. 1341 Bormann, "Neighbor Discovery Optimization for IPv6 over 1342 Low-Power Wireless Personal Area Networks (6LoWPANs)", 1343 RFC 6775, DOI 10.17487/RFC6775, November 2012, 1344 . 1346 [RFC6997] Goyal, M., Ed., Baccelli, E., Philipp, M., Brandt, A., and 1347 J. Martocci, "Reactive Discovery of Point-to-Point Routes 1348 in Low-Power and Lossy Networks", RFC 6997, 1349 DOI 10.17487/RFC6997, August 2013, 1350 . 1352 [RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and 1353 Lossy Networks", RFC 7102, DOI 10.17487/RFC7102, January 1354 2014, . 1356 [Second6TischPlugtest] 1357 "2nd 6Tisch Plugtest", . 1360 Authors' Addresses 1362 Maria Ines Robles 1363 Ericsson 1364 Hirsalantie 11 1365 Jorvas 02420 1366 Finland 1368 Email: maria.ines.robles@ericsson.com 1370 Michael C. Richardson 1371 Sandelman Software Works 1372 470 Dawson Avenue 1373 Ottawa, ON K1Z 5V7 1374 CA 1376 Email: mcr+ietf@sandelman.ca 1377 URI: http://www.sandelman.ca/mcr/ 1379 Pascal Thubert 1380 Cisco Systems, Inc 1381 Village d'Entreprises Green Side 400, Avenue de Roumanille 1382 Batiment T3, Biot - Sophia Antipolis 06410 1383 France 1385 Email: pthubert@cisco.com