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Checking references for intended status: Informational ---------------------------------------------------------------------------- == Outdated reference: A later version (-13) exists of draft-ietf-6man-rfc2460bis-05 ** Obsolete normative reference: RFC 2460 (Obsoleted by RFC 8200) == Outdated reference: A later version (-30) exists of draft-ietf-6tisch-architecture-10 == Outdated reference: A later version (-05) exists of draft-ietf-roll-routing-dispatch-00 Summary: 1 error (**), 0 flaws (~~), 4 warnings (==), 1 comment (--). 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 Intended status: Informational M. Richardson 5 Expires: January 19, 2017 SSW 6 P. Thubert 7 Cisco 8 July 18, 2016 10 When to use RFC 6553, 6554 and IPv6-in-IPv6 11 draft-richardson-roll-useofrplinfo-2460bis-01 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 January 19, 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 . . . . . . . 10 63 5.2. Example of Flow from root to RPL-aware-leaf . . . . . . . 11 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 . . . . . 12 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 . . . . . 13 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 16 73 5.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware- 74 leaf . . . . . . . . . . . . . . . . . . . . . . . . . . 17 75 6. Non Storing mode . . . . . . . . . . . . . . . . . . . . . . 17 76 6.1. Example of Flow from RPL-aware-leaf to root . . . . . . . 18 77 6.2. Example of Flow from root to RPL-aware-leaf . . . . . . . 18 78 6.3. Example of Flow from root to not-RPL-aware-leaf . . . . . 19 79 6.4. Example of Flow from not-RPL-aware-leaf to root . . . . . 20 80 6.5. Example of Flow from RPL-aware-leaf to Internet . . . . . 20 81 6.6. Example of Flow from Internet to RPL-aware-leaf . . . . . 21 82 6.7. Example of Flow from not-RPL-aware-leaf to Internet . . . 22 83 6.8. Example of Flow from Internet to non-RPL-aware-leaf . . . 22 84 6.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf . . 23 85 6.10. Example of Flow from RPL-aware-leaf to not-RPL-aware-leaf 24 86 6.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 25 87 6.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware- 88 leaf . . . . . . . . . . . . . . . . . . . . . . . . . . 25 89 7. Observations about the problem . . . . . . . . . . . . . . . 26 90 7.1. Storing mode . . . . . . . . . . . . . . . . . . . . . . 26 91 7.2. Non-Storing mode . . . . . . . . . . . . . . . . . . . . 27 92 8. 6LoRH Compression cases . . . . . . . . . . . . . . . . . . . 27 93 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28 94 10. Security Considerations . . . . . . . . . . . . . . . . . . . 28 95 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 28 96 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 28 97 12.1. Normative References . . . . . . . . . . . . . . . . . . 28 98 12.2. Informative References . . . . . . . . . . . . . . . . . 29 99 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 30 101 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) and an 130 efficient IP-in-IP technique. Uses cases proposed for the 131 [Second6TischPlugtest] involving 6loRH. 133 2. Terminology and Requirements Language 135 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 136 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 137 document are to be interpreted as described in RFC 2119 [RFC2119]. 139 Terminology defined in [RFC7102] applies to this document: LBR, LLN, 140 RPL, RPL Domain and ROLL. 142 2.1. hop-by-hop IPv6-in-IPv6 headers 144 The term "hop-by-hop IPv6-in-IPv6" header refers to: adding a header 145 that originates from a node to an adjacent node, using the addresses 146 (usually the GUA or ULA, but could use the link-local addresses) of 147 each node. If the packet must traverse multiple hops, then it must 148 be decapsulated at each hop, and then re-encapsulated again in a 149 similar fashion. 151 3. Sample/reference topology 153 A RPL network is composed of a 6LBR (6LoWPAN Border Router), Backbone 154 Router (6BBR), 6LR (6LoWPAN Router) and 6LN (6LoWPAN Node) as leaf 155 logically organized in a DODAG structure (Destination Oriented 156 Directed Acyclic Graph). 158 RPL defines the RPL Control messages (control plane), a new ICMPv6 159 [RFC4443] message with Type 155. DIS (DODAG Information 160 Solicitation), DIO (DODAG Information Object) and DAO (Destination 161 Advertisement Object) messages are all RPL Control messages but with 162 different Code values. 164 RPL supports two modes of Downward traffic: in storing mode (RPL-SM), 165 it is fully stateful or an in non-storing (RPL-NSM), it is fully 166 source routed. A RPL Instance is either fully storing or fully non- 167 storing, i.e. a RPL Instance with a combination of storing and non- 168 storing nodes is not supported with the current specifications at the 169 time of writing this document. 171 +--------------+ 172 | Upper Layers | 173 | | 174 +--------------+ 175 | RPL | 176 | | 177 +--------------+ 178 | ICMPv6 | 179 | | 180 +--------------+ 181 | IPv6 | 182 | | 183 +--------------+ 184 | 6LoWPAN | 185 | | 186 +--------------+ 187 | PHY-MAC | 188 | | 189 +--------------+ 191 Figure 1: RPL Stack. 193 +---------+ 194 +---+Internet | 195 | +---------+ 196 | 197 +----+--+ 198 | DODAG | node:01 199 +---------+ Root +----------+ 200 | | 6LBR | | 201 | +----+--+ | 202 | | | 203 | | | 204 ... ... ... 205 | | | 206 +-----+-+ +--+---+ +--+---+ 207 |6LR | | | | | 208 +-----+ | | | | | 209 | | 11 | | 12 | | 13 +------+ 210 | +-----+-+ +-+----+ +-+----+ | 211 | | | | | 212 | | | | | 213 | 21 | 22 | 23 | 24 | 25 214 +-+---+ +-+---+ +--+--+ +- --+ +---+-+ 215 |Leaf | | | | | |Leaf| |Leaf | 216 | 6LN | | | | | | 6LN| | 6LN | 217 +-----+ +-----+ +-----+ +----+ +-----+ 219 Figure 2: A reference RPL Topology. 221 The numbers in or above the nodes are there so that they may be 222 referenced in subsequent sections. In the figure 2, 6LN can be a 223 router or a host. The 6LN leaf marked as (21) and (25) are routers. 224 The leaf marked 6LN (24) is a device which does not speak RPL at all 225 (not-RPL-aware), but uses Router-Advertisements, 6LowPAN DAR/DAC and 226 efficient-ND only to participate in the network [RFC6775]. In the 227 document this leaf (24) is mentioned as well as IPv6 node. The 6LBR 228 in the figure is the root of the Global DODAG. 230 This document is in part motivated by the work that is ongoing at the 231 6TiSCH working group. The 6TiSCH architecture 232 [I-D.ietf-6tisch-architecture] draft explains the network 233 architecture of a 6TiSCH network. This architecture is used for the 234 remainder of this document. 236 The scope of the 6TiSCH (IPv6 over the TSCH mode of IEEE 802.15.4e) 237 Architecture is a Backbone Link that federates multiple LLNs (mesh) 238 as a single IPv6 Multi-Link Subnet. Each LLN in the subnet is 239 anchored at a Backbone Router (6BBR). The Backbone Routers 240 interconnect the LLNs over the Backbone Link and emulate that the LLN 241 nodes are present on the Backbone thus creating a so-called: Multi- 242 Link Subnet. An LLN node can move freely from an LLN anchored at a 243 Backbone Router to another LLN anchored at the same or a different 244 Backbone Router inside the Multi-Link Subnet and conserve its 245 addresses. 247 +---------+ 248 +---+Internet | 249 | +---------+ 250 | 251 | 252 +-----+ 253 | | Border Router to the RPL domain 254 | | (may be a RPL virtual root) 255 +-----+ 256 | 257 | Backbone 258 +-------------------+-------------------+ 259 | | | 260 +-----+ +-----+ +-----+ 261 | | Backbone | | Backbone | | Backbone 262 | | router | | router | | router 263 +|---|+ +-|||-+ +-[_]-+ 264 | | PCI-exp / | \ USB | Ethernet 265 ( ) ( ) ( )( )( ) (6LBR == RPL DODAG root) 266 o o o o o o o o o o o o 267 o o o o o o o o o o o o o o o o 268 o o o o o o o o o o 6LR == RPL router) o o 269 o o o o o o o z 270 o o o o o o (6LoWPAN Host) 272 <----------------------- RPL Instances ------------------------> 274 Figure 3: RPL domain architecture 276 4. Use cases 278 In data plane context a combination of RFC6553, RFC6554 and IPv6-in- 279 IPv6 encapsulation is going to be analyzed for the following traffic 280 flows. 282 This version of the document assumes the changes in 283 [I-D.ietf-6man-rfc2460bis] are passed. 285 RPL-aware-leaf to root 287 root to RPL-aware-leaf 289 not-RPL-aware-leaf to root 291 root to not-RPL-aware-leaf 293 RPL-aware-leaf to Internet 295 Internet to RPL-aware-leaf 297 not-RPL-aware-leaf to Internet 299 Internet to not-RPL-aware-leaf 301 RPL-aware-leaf to RPL-aware-leaf (storing and non-storing) 303 RPL-aware-leaf to not-RPL-aware-leaf (non-storing) 305 not-RPL-aware-leaf to RPL-aware-leaf (storing and non-storing) 307 not-RPL-aware-leaf to not-RPL-aware-leaf (non-storing) 309 This document assumes the rule that a Header cannot be inserted or 310 removed on the fly inside an IPv6 packet that is being routed. This 311 is a fundamental precept of the IPv6 architecture as outlined in 312 [RFC2460] is that Extensions may not be added or removed except by 313 the sender or the receiver. (A revision to RFC2460 considered 314 changing this rule, but has kept it) 316 But, options in the Hop-by-Hop option which are marked with option 317 type 01 ([RFC2460] section 4.2 and [I-D.ietf-6man-rfc2460bis]) SHOULD 318 be ignored when received by a host or router which does not 319 understand that option. 321 This means that in general, any packet that leaves the RPL domain of 322 an LLN (or leaves the LLN entirely) will NOT be discarded, even if it 323 has the [RFC6553] RPL Option Header known as the RPI or [RFC6554] 324 SRH3 Extension Header (S)RH3. 326 With abolition of one of these rules it means that the RPI Hop-by-Hop 327 option MAY be left in place even if the end host does host understand 328 it. This collapses many of the cases above (where it says "or") 330 An intermediate router that needs to add an extension header (SHR3 or 331 RPI Option) must encapsulate the packet in an (additional) outer IP 332 header where the new header can be placed. 334 This also means that a Header can only be removed by an intermediate 335 router if it is placed in an encapsulating IPv6 Header, and in that 336 case, the whole encapsulating header must be removed - a replacement 337 may be added. Further, an intermediate router can only remove such 338 an outer header if that outer header has the router as the 339 destination! 341 Both RPI and RH3 headers may be modified by routers on the path of 342 the packet without the need to add to remove an encapsulating header. 343 Both headers were designed with this modification in mind, and both 344 the RPL RH and the RPL option are marked mutable but recoverable, so 345 an IPsec AH security header can be applied across these headers, but 346 it may not secure all the values in those headers. 348 RPI should be present in every single RPL data packet. There is one 349 exception in non-storing mode: when a packet is going down from the 350 root. In a downward non-storing mode, the entire route is written, 351 so there can be no loops by construction, nor any confusion about 352 which forwarding table to use. There may be cases (such as in 353 6tisch) where the instanceID may still be needed to pick an 354 appropriate priority or channel at each hop. 356 In tables, the term "RPL aware leaf" is has been shortened to "Raf", 357 and "not-RPL aware leaf" has been shortened to "~Raf" to make the 358 table fit in available space. 360 The earlier examples are more complete to make sure that the process 361 is clear, while later examples are more consise. 363 5. Storing mode 365 This table summarizes what headers are needed in the following 366 scenarios, and indicates the IP-in-IP header must be inserted on a 367 hop-by-hop basis, and when it can target the destination node 368 directly. There are three possible situations: hop-by-hop necessary 369 (indicated by "hop"), or destination address possible (indicated by 370 "dst"). In all cases hop by hop can be used. In cases where no IP- 371 in-IP header is needed, the column is left blank. 373 The leaf can be a router 6LR or a host indicated as 6LN. 375 +--------------+-------+-------+-----------+---------------+ 376 | Use Case | RPI | RH3 | IP-in-IP | IP-in-IP dst | 377 +--------------+-------+-------+-----------+---------------+ 378 | Raf to root | Yes | No | No | -- | 379 | root to Raf | Yes | No | No | -- | 380 | root to ~Raf | Yes | No | Yes | hop | 381 | ~Raf to root | Yes | No | Yes | root | 382 | Raf to Int | Yes | No | Yes | root | 383 | Int to Raf | Yes | No | Yes | raf | 384 | ~Raf to Int | Yes | No | Yes | root | 385 | Int to ~Raf | Yes | No | Yes | hop | 386 | Raf to Raf | Yes | No | No | -- | 387 | Raf to ~Raf | Yes | No | Yes | hop | 388 | ~Raf to Raf | Yes | No | Yes | dst | 389 | ~Raf to ~Raf | Yes | No | Yes | hop | 390 +--------------+-------+-------+-----------+---------------+ 392 Table 1: Headers needed in Storing mode: RPI, RH3, IP-in-IP 393 encapsulation 395 5.1. Example of Flow from RPL-aware-leaf to root 397 In storing mode, RFC 6553 (RPI) is used to send RPL Information 398 instanceID and rank information. 400 As stated in Section 16.2 of [RFC6550] a RPL-aware-leaf node does 401 not generally issue DIO messages; a leaf node accepts DIO messages 402 from upstream. (When the inconsistency in routing occurs, a leaf 403 node will generate a DIO with an infinite rank, to fix it). It may 404 issue DAO and DIS messages though it generally ignores DAO and DIS 405 messages. 407 In storing mode, RFC 6553 (RPI) is used to send RPL Information 408 instanceID and rank information. 410 In this case the flow comprises: 412 RPL-aware-leaf (6LN) --> 6LR --> 6LR,... --> root (6LBR) 414 As it was mentioned In this document 6LRs, 6LBR are always full- 415 fledge RPL routers, and are the RPL root node. 417 The 6LN inserts the RPI header, and sends the packet to 6LR which 418 decrements the rank in RPI and sends the packet up. When the packet 419 arrives at 6LBR, the RPI is removed and the packet is processed. 421 No IP-in-IP header is required. 423 The RPI header can be removed by the 6LBR because the packet is 424 addressed to the 6LBR. The 6LN must know that it is communicating 425 with the 6LBR in order to be able to make use of this scenario. The 426 6LN can know the address of the 6LBR because it knows the address of 427 the root via the DODAGID in the DIO messages. 429 +-------------------+-----+------+------+ 430 | Header | 6LN | 6LR | 6LBR | 431 +-------------------+-----+------+------+ 432 | Inserted headers | RPI | -- | -- | 433 | Removed headers | -- | -- | RPI | 434 | Re-added headers | -- | -- | -- | 435 | Modified headers | -- | RPI | -- | 436 | Untouched headers | -- | -- | -- | 437 +-------------------+-----+------+------+ 439 Storing: Summary of the use of headers from RPL-aware-leaf to root 441 5.2. Example of Flow from root to RPL-aware-leaf 443 In this case the flow comprises: 445 root (6LBR)--> 6LR --> RPL-aware-leaf (6LN) 447 In this case the 6LBR insert RPI header and send the packet down, the 448 6LR is going to increment the rank in RPI (examines instanceID for 449 multiple tables), the packet is processed in 6LN and RPI removed. 451 No IP-in-IP header is required. 453 +-------------------+------+-------+------+ 454 | Header | 6LBR | 6LR | 6LN | 455 +-------------------+------+-------+------+ 456 | Inserted headers | RPI | -- | -- | 457 | Removed headers | -- | -- | RPI | 458 | Re-added headers | -- | -- | -- | 459 | Modified headers | -- | RPI | -- | 460 | Untouched headers | -- | -- | -- | 461 +-------------------+------+-------+------+ 463 Storing: Summary of the use of headers from root to RPL-aware-leaf 465 5.3. Example of Flow from root to not-RPL-aware-leaf 467 In this case the flow comprises: 469 root (6LBR)--> 6LR --> not-RPL-aware-leaf (6LN) 470 As the RPI extension can be ignored by the not-RPL-aware leaf, this 471 situation is identical to the previous scenario. 473 +-------------------+------+-----+------+ 474 | Header | 6LBR | 6LR | IPv6 | 475 +-------------------+------+-----+------+ 476 | Inserted headers | -- | -- | -- | 477 | Removed headers | -- | -- | -- | 478 | Re-added headers | -- | -- | -- | 479 | Modified headers | -- | -- | -- | 480 | Untouched headers | -- | -- | -- | 481 +-------------------+------+-----+------+ 483 Storing: Summary of the use of headers from root to not-RPL-aware- 484 leaf 486 5.4. Example of Flow from not-RPL-aware-leaf to root 488 In this case the flow comprises: 490 not-RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) 492 When the packet arrives from IPv6 node to 6LR, the 6LR will insert an 493 RPI header, encapsuladed in a IPv6-in-IPv6 header. The IPv6-in-IPv6 494 header can be addressed to the next hop, or to the root. The root 495 removes the header and processes the packet. 497 +-------------------+------+----------------+---------------+ 498 | Header | IPv6 | 6LR | 6LBR | 499 +-------------------+------+----------------+---------------+ 500 | Inserted headers | -- | IP-in-IP(RPI) | -- | 501 | Removed headers | -- | -- | IP-in-IP(RPI) | 502 | Re-added headers | -- | -- | -- | 503 | Modified headers | -- | -- | -- | 504 | Untouched headers | -- | -- | -- | 505 +-------------------+------+----------------+---------------+ 507 Storing: Summary of the use of headers from not-RPL-aware-leaf to 508 root 510 5.5. Example of Flow from RPL-aware-leaf to Internet 512 RPL information from RFC 6553 MAY go out to Internet as it will be 513 ignored by nodes which have not been configured to be RPI aware. 515 In this case the flow comprises: 517 RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) --> Internet 518 No IP-in-IP header is required. 520 +-------------------+------+------+------+----------+ 521 | Header | 6LN | 6LR | 6LBR | Internet | 522 +-------------------+------+------+------+----------+ 523 | Inserted headers | RPI | -- | -- | -- | 524 | Removed headers | -- | -- | -- | -- | 525 | Re-added headers | -- | -- | -- | -- | 526 | Modified headers | -- | RPI | -- | -- | 527 | Untouched headers | -- | -- | -- | -- | 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) --> 6LR --> RPL-aware-leaf (6LN) 539 When the packet arrives from Internet to 6LBR the RPI header is added 540 in a outer IPv6-in-IPv6 header and sent to 6LR, which modifies the 541 rank in the RPI. When the packet arrives at 6LN the RPI header is 542 removed and the packet processed. 544 +-----------------+----------+---------------+------+---------------+ 545 | Header | Internet | 6LBR | 6LR | 6LN | 546 +-----------------+----------+---------------+------+---------------+ 547 | Inserted | -- | IP-in-IP(RPI) | -- | -- | 548 | headers | | | | | 549 | Removed headers | -- | -- | -- | IP-in-IP(RPI) | 550 | Re-added | -- | -- | -- | -- | 551 | headers | | | | | 552 | Modified | -- | -- | RPI | -- | 553 | headers | | | | | 554 | Untouched | -- | -- | -- | -- | 555 | headers | | | | | 556 +-----------------+----------+---------------+------+---------------+ 558 Storing: Summary of the use of headers from Internet to RPL-aware- 559 leaf 561 5.7. Example of Flow from not-RPL-aware-leaf to Internet 563 In this case the flow comprises: 565 not-RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) --> Internet 566 The 6LR node will add an IP-in-IP(RPI) header addressed either to the 567 root, or hop-by-hop such that the root can remove the RPI header 568 before passing upwards. 570 The originating node will ideally leave the IPv6 flow label as zero 571 so that it can be better compressed through the LLN, and the 6LBR 572 will set the flow label to a non-zero value when sending to the 573 Internet. 575 +-----------------+------+---------------+---------------+----------+ 576 | Header | 6LN | 6LR | 6LBR | Internet | 577 +-----------------+------+---------------+---------------+----------+ 578 | Inserted | -- | IP-in-IP(RPI) | -- | -- | 579 | headers | | | | | 580 | Removed headers | -- | -- | IP-in-IP(RPI) | -- | 581 | Re-added | -- | -- | -- | -- | 582 | headers | | | | | 583 | Modified | -- | -- | -- | -- | 584 | headers | | | | | 585 | Untouched | -- | -- | -- | -- | 586 | headers | | | | | 587 +-----------------+------+---------------+---------------+----------+ 589 Storing: Summary of the use of headers from not-RPL-aware-leaf to 590 Internet 592 5.8. Example of Flow from Internet to non-RPL-aware-leaf 594 In this case the flow comprises: 596 Internet --> root (6LBR) --> 6LR --> not-RPL-aware-leaf (6LN) 598 The 6LBR will have to add an RPI header within an IP-in-IP header. 599 The IP-in-IP can be addressed to the not-RPL-aware-leaf, leaving the 600 RPI inside. 602 The 6LBR MAY set the flow label on the inner IP-in-IP header to zero 603 in order to aid in compression, as the packet will not emerge again 604 from the LLN. 606 +-----------------+----------+---------------+---------------+------+ 607 | Header | Internet | 6LBR | 6LR | IPv6 | 608 +-----------------+----------+---------------+---------------+------+ 609 | Inserted | -- | IP-in-IP(RPI) | -- | -- | 610 | headers | | | | | 611 | Removed headers | -- | -- | IP-in-IP(RPI) | -- | 612 | Re-added | -- | -- | -- | -- | 613 | headers | | | | | 614 | Modified | -- | -- | -- | -- | 615 | headers | | | | | 616 | Untouched | -- | -- | -- | -- | 617 | headers | | | | | 618 +-----------------+----------+---------------+---------------+------+ 620 Storing: Summary of the use of headers from Internet to non-RPL- 621 aware-leaf 623 5.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf 625 In [RFC6550] RPL allows a simple one-hop optimization for both 626 storing and non-storing networks. A node may send a packet destined 627 to a one-hop neighbor directly to that node. Section 9 in [RFC6550]. 629 In this case the flow comprises: 631 6LN --> 6LR --> common parent (6LR) --> 6LR --> 6LN 633 This case is assumed in the same RPL Domain. In the common parent, 634 the direction of RPI is changed (from increasing to decreasing the 635 rank). 637 While the 6LR nodes will update the RPI, no node needs to add or 638 remove the RPI, so no IP-in-IP headers are necessary. This may be 639 done regardless of where the destination is, as the included RPI will 640 be ignored by the receiver. 642 +-------------+-------+---------------+---------------+-----+-------+ 643 | Header | 6LN | 6LR | 6LR (common | 6LR | 6LN | 644 | | src | | parent) | | dst | 645 +-------------+-------+---------------+---------------+-----+-------+ 646 | Inserted | RPI | -- | -- | -- | -- | 647 | headers | | | | | | 648 | Removed | -- | -- | -- | -- | RPI | 649 | headers | | | | | | 650 | Re-added | -- | -- | -- | -- | -- | 651 | headers | | | | | | 652 | Modified | -- | RPI | RPI | -- | -- | 653 | headers | | (decreasing | (increasing | | | 654 | | | rank) | rank) | | | 655 | Untouched | -- | -- | -- | -- | -- | 656 | headers | | | | | | 657 +-------------+-------+---------------+---------------+-----+-------+ 659 Storing: Summary of the use of headers for RPL-aware-leaf to RPL- 660 aware-leaf 662 5.10. Example of Flow from RPL-aware-leaf to non-RPL-aware-leaf 664 In this case the flow comprises: 666 6LN --> 6LR --> common parent (6LR) --> 6LR --> not-RPL-aware 6LN 668 This situation is identical to the situation Section 5.9 670 5.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 672 In this case the flow comprises: 674 not-RPL-aware 6LN --> 6LR --> common parent (6LR) --> 6LR --> 6LN 676 The 6LR receives the packet from the the IPv6 node and inserts and 677 the RPI header encapsulated in IPv6-in-IPv6 header. The IP-in-IP 678 header is addressed to the destinion 6LN. 680 +--------+------+------------+------------+------------+------------+ 681 | Header | IPv6 | 6LR | common | 6LR | 6LN | 682 | | | | parent | | | 683 | | | | (6LR) | | | 684 +--------+------+------------+------------+------------+------------+ 685 | Insert | -- | IP-in- | -- | -- | -- | 686 | ed hea | | IP(RPI) | | | | 687 | ders | | | | | | 688 | Remove | -- | -- | -- | -- | IP-in- | 689 | d head | | | | | IP(RPI) | 690 | ers | | | | | | 691 | Re- | -- | -- | -- | -- | -- | 692 | added | | | | | | 693 | header | | | | | | 694 | s | | | | | | 695 | Modifi | -- | -- | IP-in- | IP-in- | -- | 696 | ed hea | | | IP(RPI) | IP(RPI) | | 697 | ders | | | | | | 698 | Untouc | -- | -- | -- | -- | -- | 699 | hed he | | | | | | 700 | aders | | | | | | 701 +--------+------+------------+------------+------------+------------+ 703 Storing: Summary of the use of headers from not-RPL-aware-leaf to 704 RPL-aware-leaf 706 5.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-leaf 708 In this case the flow comprises: 710 not-RPL-aware 6LN (IPv6 node)--> 6LR --> root (6LBR) --> 6LR --> not- 711 RPL-aware 6LN (IPv6 node) 713 This flow is identical to Section 5.11 715 6. Non Storing mode 716 +--------------+------+------+-----------+---------------+ 717 | Use Case | RPI | RH3 | IP-in-IP | IP-in-IP dst | 718 +--------------+------+------+-----------+---------------+ 719 | Raf to root | Yes | No | No | -- | 720 | root to Raf | Yes | Yes | No | -- | 721 | root to ~Raf | No | Yes | Yes | 6LR | 722 | ~Raf to root | Yes | No | Yes | root | 723 | Raf to Int | Yes | No | Yes | root | 724 | Int to Raf | opt | Yes | Yes | dst | 725 | ~Raf to Int | Yes | No | Yes | root | 726 | Int to ~Raf | opt | Yes | Yes | 6LR | 727 | Raf to Raf | Yes | Yes | Yes | root/dst | 728 | Raf to ~Raf | Yes | Yes | Yes | root/6LR | 729 | ~Raf to Raf | Yes | Yes | Yes | root/6LN | 730 | ~Raf to ~Raf | Yes | Yes | Yes | root/6LR | 731 +--------------+------+------+-----------+---------------+ 733 Table 2: Headers needed in Non-Storing mode: RPI, RH3, IP-in-IP 734 encapsulation 736 6.1. Example of Flow from RPL-aware-leaf to root 738 In non-storing mode the leaf node uses default routing to send 739 traffic to the root. The RPI header must be included to avoid/detect 740 loops. 742 RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) 744 This situation is the same case as storing mode. 746 +-------------------+-----+-----+------+ 747 | Header | 6LN | 6LR | 6LBR | 748 +-------------------+-----+-----+------+ 749 | Inserted headers | RPI | -- | -- | 750 | Removed headers | -- | -- | RPI | 751 | Re-added headers | -- | -- | RPI | 752 | Modified headers | -- | -- | -- | 753 | Untouched headers | -- | -- | -- | 754 +-------------------+-----+-----+------+ 756 Non Storing: Summary of the use of headers from RPL-aware-leaf to 757 root 759 6.2. Example of Flow from root to RPL-aware-leaf 761 In this case the flow comprises: 763 root (6LBR)--> 6LR --> RPL-aware-leaf (6LN) 764 The 6LBR will insert an RH3, and may optionally insert an RPI header. 765 No IP-in-IP header is necessary as the traffic originates with an RPL 766 aware node. 768 +-------------------+-----------------+------+----------+ 769 | Header | 6LBR | 6LR | 6LN | 770 +-------------------+-----------------+------+----------+ 771 | Inserted headers | (opt: RPI), RH3 | -- | -- | 772 | Removed headers | -- | -- | RH3,RPI | 773 | Re-added headers | -- | -- | -- | 774 | Modified headers | -- | RH3 | -- | 775 | Untouched headers | -- | -- | -- | 776 +-------------------+-----------------+------+----------+ 778 Non Storing: Summary of the use of headers from root to RPL-aware- 779 leaf 781 6.3. Example of Flow from root to not-RPL-aware-leaf 783 In this case the flow comprises: 785 root (6LBR)--> 6LR --> not-RPL-aware-leaf (IPv6 node) 787 In 6LBR the RH3 is added, and modified in 6LR where it is fully 788 consumed, but left there. If the RPI is left present, the IPv6 node 789 which does not understand it will drop it, therefore the RPI should 790 be removed before reaching the IPv6-only node. To permit removal, an 791 IP-in-IP header (hop-by-hop) or addressed to the last 6LR is 792 necessary. Due the complete knowledge of the topology at the root, 793 the 6LBR is able to address the IP-in-IP header to the last 6LR. 795 Omitting the RPI entirely is therefore a better solution, as no IP- 796 in-IP header is necessary. 798 +-------------------+------+-----+------+ 799 | Header | 6LBR | 6LR | IPv6 | 800 +-------------------+------+-----+------+ 801 | Inserted headers | RH3 | -- | -- | 802 | Removed headers | -- | -- | -- | 803 | Re-added headers | -- | -- | -- | 804 | Modified headers | -- | RH3 | -- | 805 | Untouched headers | -- | -- | -- | 806 +-------------------+------+-----+------+ 808 Non Storing: Summary of the use of headers from root to not-RPL- 809 aware-leaf 811 6.4. Example of Flow from not-RPL-aware-leaf to root 813 In this case the flow comprises: 815 IPv6-node --> 6LR1 --> 6LR2 --> root (6LBR) 817 In this case the RPI is added by the first 6LR, encapsulated in an 818 IP-in-IP header, and is not modified in the followings 6LRs. The RPI 819 and entire packet is consumed by the root. 821 +-------------------+------+----------------+------+----------------+ 822 | Header | IPv6 | 6LR1 | 6LR2 | 6LBR | 823 +-------------------+------+----------------+------+----------------+ 824 | Inserted headers | -- | IP-in-IP(RPI) | -- | -- | 825 | Removed headers | -- | -- | -- | IP-in-IP(RPI) | 826 | Re-added headers | -- | -- | -- | -- | 827 | Modified headers | -- | -- | -- | -- | 828 | Untouched headers | -- | IP-in-IP(RPI) | -- | -- | 829 +-------------------+------+----------------+------+----------------+ 831 Non Storing: Summary of the use of headers from not-RPL-aware-leaf to 832 root 834 6.5. Example of Flow from RPL-aware-leaf to Internet 836 In this case the flow comprises: 838 RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) --> Internet 840 This case requires that the RPI be added, but remoted by the 6LBR. 841 The 6LN must therefore add the RPI inside an IP-in-IP header, 842 addressed to the root. This case is identical to storing-mode case. 844 The IPv6 flow label should be set to zero to aid in compression, and 845 the 6LBR will set it to a non-zero value when sending towards the 846 Internet. 848 +-----------------+---------------+------+---------------+----------+ 849 | Header | 6LN | 6LR | 6LBR | Internet | 850 +-----------------+---------------+------+---------------+----------+ 851 | Inserted | IP-in-IP(RPI) | -- | -- | -- | 852 | headers | | | | | 853 | Removed headers | -- | -- | IP-in-IP(RPI) | -- | 854 | Re-added | -- | -- | -- | -- | 855 | headers | | | | | 856 | Modified | -- | -- | -- | -- | 857 | headers | | | | | 858 | Untouched | -- | RPI | -- | -- | 859 | headers | | | | | 860 +-----------------+---------------+------+---------------+----------+ 862 Non Storing: Summary of the use of headers from RPL-aware-leaf to 863 Internet 865 6.6. Example of Flow from Internet to RPL-aware-leaf 867 In this case the flow comprises: 869 Internet --> root (6LBR) --> 6LR --> RPL-aware-leaf (6LN) 871 The 6LBR must add an RH3 header. As the 6LBR will know the path and 872 address of the target not, it can address the IP-in-IP header to that 873 node. The 6LBR will zero the flow label upon entry in order to aid 874 compression. 876 The RPI may be added or not. 878 +----------+----------+-----------------------+---------------+-----+ 879 | Header | Internet | 6LBR | 6LR | 6LN | 880 +----------+----------+-----------------------+---------------+-----+ 881 | Inserted | -- | IP-in-IP(RH3,opt:RPI) | -- | -- | 882 | headers | | | | | 883 | Removed | -- | -- | IP-in-IP(RH3) | -- | 884 | headers | | | | | 885 | Re-added | -- | -- | -- | -- | 886 | headers | | | | | 887 | Modified | -- | -- | IP-in-IP(RH3) | -- | 888 | headers | | | | | 889 | Untouche | -- | -- | -- | -- | 890 | d | | | | | 891 | headers | | | | | 892 +----------+----------+-----------------------+---------------+-----+ 894 Non Storing: Summary of the use of headers from Internet to RPL- 895 aware-leaf 897 6.7. Example of Flow from not-RPL-aware-leaf to Internet 899 In this case the flow comprises: 901 not-RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) --> Internet 903 In this case the flow label is recommended to be zero in the IPv6 904 node. As RPL headers are added in the IPv6 node, the first 6LN will 905 add an RPI header inside a new IP-in-IP header. The IP-in-IP header 906 will be addressed to the root. This case is identical to the 907 storing-mode case. 909 +-----------------+------+---------------+---------------+----------+ 910 | Header | IPv6 | 6LR | 6LBR | Internet | 911 +-----------------+------+---------------+---------------+----------+ 912 | Inserted | -- | IP-in-IP(RPI) | -- | -- | 913 | headers | | | | | 914 | Removed headers | -- | -- | IP-in-IP(RPI) | -- | 915 | Re-added | -- | -- | -- | -- | 916 | headers | | | | | 917 | Modified | -- | -- | -- | -- | 918 | headers | | | | | 919 | Untouched | -- | -- | -- | -- | 920 | headers | | | | | 921 +-----------------+------+---------------+---------------+----------+ 923 Non Storing: Summary of the use of headers from not-RPL-aware-leaf to 924 Internet 926 6.8. Example of Flow from Internet to non-RPL-aware-leaf 928 In this case the flow comprises: 930 Internet --> root (6LBR) --> 6LR --> not-RPL-aware-leaf (6LN) 932 The 6LBR must add an RH3 header inside an IP-in-IP header. The 6LBR 933 will know the path, and will recognize that the final node is not an 934 RPL capable node as it will have received the connectivity DAO from 935 the nearest 6LR. The 6LBR can therefore make the IP-in-IP header 936 destination be the last 6LR. The 6LBR will zero the flow label upon 937 entry in order to aid compression. 939 +----------+---------+-----------------------+---------------+------+ 940 | Header | Interne | 6LBR | 6LR | IPv6 | 941 | | t | | | | 942 +----------+---------+-----------------------+---------------+------+ 943 | Inserted | -- | IP-in-IP(RH3,opt:RPI) | -- | -- | 944 | headers | | | | | 945 | Removed | -- | -- | IP-in-IP(RH3, | -- | 946 | headers | | | RPI) | | 947 | Re-added | -- | -- | -- | -- | 948 | headers | | | | | 949 | Modified | -- | -- | -- | -- | 950 | headers | | | | | 951 | Untouche | -- | -- | -- | -- | 952 | d | | | | | 953 | headers | | | | | 954 +----------+---------+-----------------------+---------------+------+ 956 NonStoring: Summary of the use of headers from Internet to non-RPL- 957 aware-leaf 959 6.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf 961 In this case the flow comprises: 963 6LN --> 6LR --> root (6LBR) --> 6LR --> 6LN 965 This case involves only nodes in same RPL Domain. The originating 966 node will add an RPI header to the original packet, and send the 967 packet upwards. 969 The originating node could put the RPI into an IP-in-IP header 970 addressed to the root, so that the 6LBR can remove that header. 972 The 6LBR will need to insert an RH3 header, which requires that it 973 add an IP-in-IP header. It may be able to remove the RPI if it was 974 contained in an IP-in-IP header addressed to it. Otherwise, there 975 may be an RPI header buried inside the inner IP header, which should 976 get ignored. 978 Networks that use the RPL P2P extension [RFC6997] are essentially 979 non-storing DODAGs and fall into this scenario. 981 +----------+---------------+--------------+-----+-------------------+ 982 | Header | 6LN src | 6LBR | 6LR | 6LN dst | 983 +----------+---------------+--------------+-----+-------------------+ 984 | Inserted | IP-in-IP(RPI) | IP-in-IP(RH3 | -- | -- | 985 | headers | | to 6LN,RPI) | | | 986 | Removed | -- | -- | -- | IP-in-IP(RH3,RPI) | 987 | headers | | | | | 988 | Re-added | -- | -- | -- | -- | 989 | headers | | | | | 990 | Modified | -- | -- | -- | -- | 991 | headers | | | | | 992 | Untouche | -- | -- | -- | -- | 993 | d | | | | | 994 | headers | | | | | 995 +----------+---------------+--------------+-----+-------------------+ 997 Non Storing: Summary of the use of headers for RPL-aware-leaf to RPL- 998 aware-leaf 1000 6.10. Example of Flow from RPL-aware-leaf to not-RPL-aware-leaf 1002 In this case the flow comprises: 1004 6LN --> 6LR --> root (6LBR) --> 6LR --> not-RPL-aware 6LN 1006 As in the previous case, the 6LN will insert an RPI header which MUST 1007 be in an IP-in-IP header addressed to the root so that the 6LBR can 1008 remove this RPI. The 6LBR will then insert an RH3 inside a new IP- 1009 in-IP header addressed to the 6LN above the destination node. 1011 +-----------+---------------+---------------+----------------+------+ 1012 | Header | 6LN | 6LBR | 6LR | IPv6 | 1013 +-----------+---------------+---------------+----------------+------+ 1014 | Inserted | IP-in-IP(RPI) | IP-in-IP(RH3, | -- | -- | 1015 | headers | | opt RPI) | | | 1016 | Removed | -- | IP-in-IP(RPI) | IP-in-IP(RH3, | -- | 1017 | headers | | | opt RPI) | | 1018 | Re-added | -- | -- | -- | -- | 1019 | headers | | | | | 1020 | Modified | -- | -- | -- | -- | 1021 | headers | | | | | 1022 | Untouched | -- | -- | -- | -- | 1023 | headers | | | | | 1024 +-----------+---------------+---------------+----------------+------+ 1026 Non Storing: Summary of the use of headers from RPL-aware-leaf to 1027 not-RPL-aware-leaf 1029 6.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 1031 In this case the flow comprises: 1033 not-RPL-aware 6LN --> 6LR --> root (6LBR) --> 6LR --> 6LN 1035 This scenario is mostly identical to the previous one. The RPI is 1036 added by the first 6LR inside an IP-in-IP header addressed to the 1037 root. The 6LBR will remove this RPI, and add it's own IP-in-IP 1038 header containing an RH3 header. 1040 +------------+------+---------------+---------------+---------------+ 1041 | Header | IPv6 | 6LR | 6LBR | 6LN | 1042 +------------+------+---------------+---------------+---------------+ 1043 | Inserted | -- | IP-in-IP(RPI) | IP-in-IP(RH3) | -- | 1044 | headers | | | | | 1045 | Removed | -- | IP-in-IP(RPI) | -- | IP-in-IP(RH3) | 1046 | headers | | | | | 1047 | Re-added | -- | -- | -- | -- | 1048 | headers | | | | | 1049 | Modified | -- | -- | -- | -- | 1050 | headers | | | | | 1051 | Untouched | -- | -- | -- | -- | 1052 | headers | | | | | 1053 +------------+------+---------------+---------------+---------------+ 1055 Non Storing: Summary of the use of headers from not-RPL-aware-leaf to 1056 RPL-aware-leaf 1058 6.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-leaf 1060 In this case the flow comprises: 1062 not-RPL-aware 6LN --> 6LR --> root (6LBR) --> 6LR --> not-RPL-aware 1063 6LN 1065 This scenario is the combination of the previous two cases. 1067 +----------+-----+-------------+--------------+--------------+------+ 1068 | Header | IPv | 6LR | 6LBR | 6LR | IPv6 | 1069 | | 6 | | | | | 1070 +----------+-----+-------------+--------------+--------------+------+ 1071 | Inserted | -- | IP-in- | IP-in- | -- | -- | 1072 | headers | | IP(RPI) | IP(RH3) | | | 1073 | Removed | -- | -- | IP-in- | IP-in- | -- | 1074 | headers | | | IP(RPI) | IP(RH3, opt | | 1075 | | | | | RPI) | | 1076 | Re-added | -- | -- | -- | -- | -- | 1077 | headers | | | | | | 1078 | Modified | -- | -- | -- | -- | -- | 1079 | headers | | | | | | 1080 | Untouche | -- | -- | -- | -- | -- | 1081 | d | | | | | | 1082 | headers | | | | | | 1083 +----------+-----+-------------+--------------+--------------+------+ 1085 Non Storing: Summary of the use of headers from not-RPL-aware-leaf to 1086 not-RPL-aware-leaf 1088 7. Observations about the problem 1090 7.1. Storing mode 1092 In the completely general storing case, which includes not-RPL aware 1093 leaf nodes, it is not possible for a sending node to know if the 1094 destination is RPL aware, and therefore it must always use hop-by-hop 1095 IP-in-IP encapsulation, and it can never omit the IP-in-IP 1096 encapsulation. See table Table 1 1098 The simplest fully general stiaution for storing mode is to always 1099 put in hop-by-hop IP-in-IP headers. [I-D.ietf-roll-routing-dispatch] 1100 shows that this hop-by-hop IP-in-IP header can be compressed down to 1101 {TBD} bytes. 1103 There are potential significant advantages to having a single code 1104 path that always processes IP-in-IP headers with no options. 1106 If all RPL aware nodes can be told/configured that there are no non- 1107 RPL aware leaf nodes, then the only case where an IP-in-IP header is 1108 needed is when communicating outside the LLN. The 6LBR knows well 1109 when the communication is from the outside, and the 6LN can tell by 1110 comparing the destination address to the prefix provided in the PIO. 1111 If it is known that there are no communications outside the RPL 1112 domain (noting that the RPL domain may well extend to outside the 1113 LLN), then RPI headers can be included in all packets, and IP-in-IP 1114 headers are *never* needed. This may be significantly advantageous 1115 in relatively closed systems such as in building or industrial 1116 automation. Again, there are advantages to having a single code 1117 path. 1119 In order to support the above two cases with full generality, the 1120 different situations (always do IP-in-IP vs never use IP-in-IP) 1121 should be signaled in the RPL protocol itself. 1123 7.2. Non-Storing mode 1125 This the non-storing case, dealing with non-RPL aware leaf nodes is 1126 much easier as the 6LBR (DODAG root) has complete knowledge about the 1127 connectivity of all nodes, and all traffic flows through the root 1128 node. 1130 The 6LBR can recognize non-RPL aware leaf nodes because it will 1131 receive a DAO about that node from the 6LN immediately above that 1132 node. This means that the non-storing mode case can avoid ever using 1133 hop-by-hop IP-in-IP headers. 1135 It is unclear what it would mean for an RH3 header to be present in a 1136 hop-by-hop IP-in-IP header. The receiving node ought to consume the 1137 IP-in-IP header, and therefore consume the RH3 as well, and then 1138 attempt to send the packet again. But intermediate 6LN nodes would 1139 not know how to forward the packet, so the RH3 would need to be 1140 retained. This is a new kind of IPv6 packet processing. Therefore 1141 it may be that on the outbound leg of non-storing RPL networks, that 1142 hop-by-hop IP-in-IP header can NOT be used. 1144 [I-D.ietf-roll-routing-dispatch] shows how the destination=root, and 1145 destination=6LN IP-in-IP header can be compressed down to {TBD} 1146 bytes. 1148 Unlike in the storing mode case, there are no need for all nodes to 1149 know about the existence of non-RPL aware nodes. Only the 6LBR needs 1150 to change when there are non-RPL aware nodes. Further, in the non- 1151 storing case, the 6LBR is informed by the DAOs when there are non-RPL 1152 aware nodes. 1154 8. 6LoRH Compression cases 1156 The [I-D.ietf-roll-routing-dispatch] proposes a compression method 1157 for RPI, RH3 and IPv6-in-IPv6. 1159 In Storing Mode, for the examples of Flow from RPL-aware-leaf to non- 1160 RPL-aware-leaf and non-RPL-aware-leaf to non-RPL-aware-leaf comprise 1161 an IP-in-IP and RPI compression headers. The type of this case is 1162 critical since IP-in-IP is encapsulating a RPI header. 1164 +--+-----+---+--------------+-----------+-------------+-------------+ 1165 |1 | 0|0 |TSE| 6LoRH Type 6 | Hop Limit | RPI - 6LoRH | LOWPAN IPHC | 1166 +--+-----+---+--------------+-----------+-------------+-------------+ 1168 Figure 4: Critical IP-in-IP (RPI). 1170 9. IANA Considerations 1172 There are no IANA considerations related to this document. 1174 10. Security Considerations 1176 The security considerations covering of [RFC6553] and [RFC6554] apply 1177 when the packets get into RPL Domain. 1179 11. Acknowledgments 1181 This work is partially funded by the FP7 Marie Curie Initial Training 1182 Network (ITN) METRICS project (grant agreement No. 607728). 1184 The authors would like to acknowledge the review, feedback, and 1185 comments of Robert Cragie, Simon Duquennoy, Cenk Guendogan, Peter van 1186 der Stok, Xavier Vilajosana and Thomas Watteyne. 1188 12. References 1190 12.1. Normative References 1192 [I-D.ietf-6man-rfc2460bis] 1193 Deering, D. and R. Hinden, "Internet Protocol, Version 6 1194 (IPv6) Specification", draft-ietf-6man-rfc2460bis-05 (work 1195 in progress), June 2016. 1197 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1198 Requirement Levels", BCP 14, RFC 2119, 1199 DOI 10.17487/RFC2119, March 1997, 1200 . 1202 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1203 (IPv6) Specification", RFC 2460, December 1998. 1205 [RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J., 1206 Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur, 1207 JP., and R. Alexander, "RPL: IPv6 Routing Protocol for 1208 Low-Power and Lossy Networks", RFC 6550, 1209 DOI 10.17487/RFC6550, March 2012, 1210 . 1212 [RFC6553] Hui, J. and JP. Vasseur, "The Routing Protocol for Low- 1213 Power and Lossy Networks (RPL) Option for Carrying RPL 1214 Information in Data-Plane Datagrams", RFC 6553, 1215 DOI 10.17487/RFC6553, March 2012, 1216 . 1218 [RFC6554] Hui, J., Vasseur, JP., Culler, D., and V. Manral, "An IPv6 1219 Routing Header for Source Routes with the Routing Protocol 1220 for Low-Power and Lossy Networks (RPL)", RFC 6554, 1221 DOI 10.17487/RFC6554, March 2012, 1222 . 1224 12.2. Informative References 1226 [I-D.ietf-6tisch-architecture] 1227 Thubert, P., "An Architecture for IPv6 over the TSCH mode 1228 of IEEE 802.15.4", draft-ietf-6tisch-architecture-10 (work 1229 in progress), June 2016. 1231 [I-D.ietf-roll-routing-dispatch] 1232 Thubert, P., Bormann, C., Toutain, L., and R. Cragie, 1233 "6LoWPAN Routing Header", draft-ietf-roll-routing- 1234 dispatch-00 (work in progress), March 2016. 1236 [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet 1237 Control Message Protocol (ICMPv6) for the Internet 1238 Protocol Version 6 (IPv6) Specification", RFC 4443, 1239 DOI 10.17487/RFC4443, March 2006, 1240 . 1242 [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. 1243 Bormann, "Neighbor Discovery Optimization for IPv6 over 1244 Low-Power Wireless Personal Area Networks (6LoWPANs)", 1245 RFC 6775, DOI 10.17487/RFC6775, November 2012, 1246 . 1248 [RFC6997] Goyal, M., Ed., Baccelli, E., Philipp, M., Brandt, A., and 1249 J. Martocci, "Reactive Discovery of Point-to-Point Routes 1250 in Low-Power and Lossy Networks", RFC 6997, 1251 DOI 10.17487/RFC6997, August 2013, 1252 . 1254 [RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and 1255 Lossy Networks", RFC 7102, DOI 10.17487/RFC7102, January 1256 2014, . 1258 [Second6TischPlugtest] 1259 "2nd 6Tisch Plugtest", . 1262 Authors' Addresses 1264 Maria Ines Robles 1265 Ericsson 1266 Hirsalantie 11 1267 Jorvas 02420 1268 Finland 1270 Email: maria.ines.robles@ericsson.com 1272 Michael C. Richardson 1273 Sandelman Software Works 1274 470 Dawson Avenue 1275 Ottawa, ON K1Z 5V7 1276 CA 1278 Email: mcr+ietf@sandelman.ca 1279 URI: http://www.sandelman.ca/ 1281 Pascal Thubert 1282 Cisco Systems, Inc 1283 Village d'Entreprises Green Side 400, Avenue de Roumanille 1284 Batiment T3, Biot - Sophia Antipolis 06410 1285 France 1287 Email: pthubert@cisco.com