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Checking references for intended status: Informational ---------------------------------------------------------------------------- == Outdated reference: A later version (-13) exists of draft-ietf-6man-rfc2460bis-06 ** Obsolete normative reference: RFC 2460 (Obsoleted by RFC 8200) == Outdated reference: A later version (-30) exists of draft-ietf-6tisch-architecture-10 == Outdated reference: A later version (-05) exists of draft-ietf-roll-routing-dispatch-00 Summary: 1 error (**), 0 flaws (~~), 4 warnings (==), 1 comment (--).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: March 17, 2017 SSW 6 P. Thubert 7 Cisco 8 September 13, 2016 10 When to use RFC 6553, 6554 and IPv6-in-IPv6 11 draft-ietf-roll-useofrplinfo-08 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 March 17, 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 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 RPL-node: It is device which implements RPL, thus we can say that the 143 device is RPL-capable or RPL-aware. Please note that the device can 144 be found inside the LLN or outside LLN. In this document a RPL-node 145 which is a leaf is called RPL-aware-leaf. 147 RPL-not-capable: It is device which do not implement RPL, thus we can 148 say that the device is not-RPL-aware. Please note that the device 149 can be found inside the LLN. In this document a not-RPL-node which 150 is a leaf is called not-RPL-aware-leaf. 152 2.1. hop-by-hop IPv6-in-IPv6 headers 154 The term "hop-by-hop IPv6-in-IPv6" header refers to: adding a header 155 that originates from a node to an adjacent node, using the addresses 156 (usually the GUA or ULA, but could use the link-local addresses) of 157 each node. If the packet must traverse multiple hops, then it must 158 be decapsulated at each hop, and then re-encapsulated again in a 159 similar fashion. 161 3. Sample/reference topology 163 A RPL network is composed of a 6LBR (6LoWPAN Border Router), Backbone 164 Router (6BBR), 6LR (6LoWPAN Router) and 6LN (6LoWPAN Node) as leaf 165 logically organized in a DODAG structure (Destination Oriented 166 Directed Acyclic Graph). 168 RPL defines the RPL Control messages (control plane), a new ICMPv6 169 [RFC4443] message with Type 155. DIS (DODAG Information 170 Solicitation), DIO (DODAG Information Object) and DAO (Destination 171 Advertisement Object) messages are all RPL Control messages but with 172 different Code values. A RPL Stack is showed in Figure 1. 174 RPL supports two modes of Downward traffic: in storing mode (RPL-SM), 175 it is fully stateful or an in non-storing (RPL-NSM), it is fully 176 source routed. A RPL Instance is either fully storing or fully non- 177 storing, i.e. a RPL Instance with a combination of storing and non- 178 storing nodes is not supported with the current specifications at the 179 time of writing this document. 181 +--------------+ 182 | Upper Layers | 183 | | 184 +--------------+ 185 | RPL | 186 | | 187 +--------------+ 188 | ICMPv6 | 189 | | 190 +--------------+ 191 | IPv6 | 192 | | 193 +--------------+ 194 | 6LoWPAN | 195 | | 196 +--------------+ 197 | PHY-MAC | 198 | | 199 +--------------+ 201 Figure 1: RPL Stack. 203 +---------+ 204 +---+Internet | 205 | +---------+ 206 | 207 +----+--+ 208 | DODAG | node:01 209 +---------+ Root +----------+ 210 | | 6LBR | | 211 | +----+--+ | 212 | | | 213 | | | 214 ... ... ... 215 | | | 216 +-----+-+ +--+---+ +--+---+ 217 |6LR | | | | | 218 +-----+ | | | | | 219 | | 11 | | 12 | | 13 +------+ 220 | +-----+-+ +-+----+ +-+----+ | 221 | | | | | 222 | | | | | 223 | 21 | 22 | 23 | 24 | 25 224 +-+---+ +-+---+ +--+--+ +- --+ +---+-+ 225 |Leaf | | | | | |Leaf| |Leaf | 226 | 6LN | | | | | | 6LN| | 6LN | 227 +-----+ +-----+ +-----+ +----+ +-----+ 229 Figure 2: A reference RPL Topology. 231 In Figure 2 is showed the reference RPL Topology for this document. 232 The numbers in or above the nodes are there so that they may be 233 referenced in subsequent sections. In the figure, a 6LN can be a 234 router or a host. The 6LN leafs marked as (21) is a RPL host that 235 does not have forwarding capability and (25) is a RPL router. The 236 leaf marked 6LN (24) is a device which does not speak RPL at all 237 (not-RPL-aware), but uses Router-Advertisements, 6LowPAN DAR/DAC and 238 efficient-ND only to participate in the network [RFC6775]. In the 239 document this leaf (24) is often named IPv6 node. The 6LBR in the 240 figure is the root of the Global DODAG. 242 This document is in part motivated by the work that is ongoing at the 243 6TiSCH working group. The 6TiSCH architecture 244 [I-D.ietf-6tisch-architecture] draft explains the network 245 architecture of a 6TiSCH network. 247 4. Use cases 249 In data plane context a combination of RFC6553, RFC6554 and IPv6-in- 250 IPv6 encapsulation is going to be analyzed for the following traffic 251 flows. 253 This version of the document assumes the changes in 254 [I-D.ietf-6man-rfc2460bis] are passed (at the time to write this 255 specification, the draft is on version 05). 257 RPL-aware-leaf to root 259 root to RPL-aware-leaf 261 not-RPL-aware-leaf to root 263 root to not-RPL-aware-leaf 265 RPL-aware-leaf to Internet 267 Internet to RPL-aware-leaf 269 not-RPL-aware-leaf to Internet 271 Internet to not-RPL-aware-leaf 273 RPL-aware-leaf to RPL-aware-leaf (storing and non-storing) 275 RPL-aware-leaf to not-RPL-aware-leaf (non-storing) 277 not-RPL-aware-leaf to RPL-aware-leaf (storing and non-storing) 279 not-RPL-aware-leaf to not-RPL-aware-leaf (non-storing) 281 This document assumes the rule that a Header cannot be inserted or 282 removed on the fly inside an IPv6 packet that is being routed. This 283 is a fundamental precept of the IPv6 architecture as outlined in 284 [RFC2460]. Extensions may not be added or removed except by the 285 sender or the receiver. 287 But, options in the Hop-by-Hop option which are marked with option 288 type 01 ([RFC2460] section 4.2 and [I-D.ietf-6man-rfc2460bis]) SHOULD 289 be ignored when received by a host or router which does not 290 understand that option. 292 This means that in general, any packet that leaves the RPL domain of 293 an LLN (or leaves the LLN entirely) will NOT be discarded, when it 294 has the [RFC6553] RPL Option Header known as the RPI or [RFC6554] 295 SRH3 Extension Header (S)RH3. 297 The recent change to the second of these rules it means that the RPI 298 Hop-by-Hop option MAY be left in place even if the end host does not 299 understand it. 301 NOTE: There is some possible security risk when the RPI information 302 is released to the Internet. At this point this is a theoretical 303 situation. It is clear that the RPI option would waste some network 304 bandwidth when it escapes. 306 An intermediate router that needs to add an extension header (SHR3 or 307 RPI Option) must encapsulate the packet in an (additional) outer IP 308 header. The new header can be placed is placed after this new outer 309 IP header. 311 A corollory is that an SHR3 or RPI Option can only be removed by an 312 intermediate router if it is placed in an encapsulating IPv6 Header, 313 which is addressed to the intermediate router. When it does so, the 314 whole encapsulating header must be removed. (A replacement may be 315 added). This sometimes can result in outer IP headers being 316 addressed to the next hop router using link-local addresses. 318 Both RPI and RH3 headers may be modified in very specific ways by 319 routers on the path of the packet without the need to add to remove 320 an encapsulating header. Both headers were designed with this 321 modification in mind, and both the RPL RH and the RPL option are 322 marked mutable but recoverable: so an IPsec AH security header can be 323 applied across these headers, but it can not secure the values which 324 mutate. 326 RPI should be present in every single RPL data packet. There is one 327 exception in non-storing mode: when a packet is going down from the 328 root. In a downward non-storing mode, the entire route is written, 329 so there can be no loops by construction, nor any confusion about 330 which forwarding table to use (as the root has already made all 331 routing decisions). There still may be cases (such as in 6tisch) 332 where the instanceID portion of the RPI header may still be needed to 333 pick an appropriate priority or channel at each hop. 335 In the tables present in this document, the term "RPL aware leaf" is 336 has been shortened to "Raf", and "not-RPL aware leaf" has been 337 shortened to "~Raf" to make the table fit in available space. 339 The earlier examples are more extensive to make sure that the process 340 is clear, while later examples are more consise. 342 5. Storing mode 344 In storing mode (fully stateful), the sender cannot determine whether 345 the destination is RPL-capable and thus would need an IP-in-IP 346 header. The IP-in-IP header needs to be addressed on a hop-by-hop 347 basis so that the last 6LR can remove the RPI header. Additionally, 348 The sender can determine if the destination is inside the LLN by 349 looking if the destination address is matched by the DIO's PIO 350 option. 352 The following table summarizes what headers are needed in the 353 following scenarios, and indicates when the IP-in-IP header must be 354 inserted on a hop-by-hop basis, and when it can target the 355 destination node directly. There are three possible situations: hop- 356 by-hop necessary (indicated by "hop"), or destination address 357 possible (indicated by "dst"). In all cases hop by hop can be used. 358 In cases where no IP-in-IP header is needed, the column is left 359 blank. 361 The leaf can be a router 6LR or a host, both indicated as 6LN. 363 +--------------+-------+-------+-----------+---------------+ 364 | Use Case | RPI | RH3 | IP-in-IP | IP-in-IP dst | 365 +--------------+-------+-------+-----------+---------------+ 366 | Raf to root | Yes | No | No | -- | 367 | root to Raf | Yes | No | No | -- | 368 | root to ~Raf | Yes | No | No | -- | 369 | ~Raf to root | Yes | No | Yes | root | 370 | Raf to Int | Yes | No | No | -- | 371 | Int to Raf | Yes | No | Yes | raf | 372 | ~Raf to Int | Yes | No | Yes | root | 373 | Int to ~Raf | Yes | No | Yes | hop | 374 | Raf to Raf | Yes | No | No | -- | 375 | Raf to ~Raf | Yes | No | No | -- | 376 | ~Raf to Raf | Yes | No | Yes | dst | 377 | ~Raf to ~Raf | Yes | No | Yes | hop | 378 +--------------+-------+-------+-----------+---------------+ 380 Table 1: Headers needed in Storing mode: RPI, RH3, IP-in-IP 381 encapsulation 383 5.1. Example of Flow from RPL-aware-leaf to root 385 In storing mode, RFC 6553 (RPI) is used to send RPL Information 386 instanceID and rank information. 388 As stated in Section 16.2 of [RFC6550] a RPL-aware-leaf node does 389 not generally issue DIO messages; a leaf node accepts DIO messages 390 from upstream. (When the inconsistency in routing occurs, a leaf 391 node will generate a DIO with an infinite rank, to fix it). It may 392 issue DAO and DIS messages though it generally ignores DAO and DIS 393 messages. 395 In this case the flow comprises: 397 RPL-aware-leaf (6LN) --> 6LR1,... --> 6LRN --> root (6LBR) 399 As it was mentioned In this document 6LRs, 6LBR are always full- 400 fledge RPL routers. 402 The 6LN inserts the RPI header, and sends the packet to 6LR which 403 decrements the rank in RPI and sends the packet up. When the packet 404 arrives at 6LBR, the RPI is removed and the packet is processed. 406 No IP-in-IP header is required. 408 The RPI header can be removed by the 6LBR because the packet is 409 addressed to the 6LBR. The 6LN must know that it is communicating 410 with the 6LBR to make use of this scenario. The 6LN can know the 411 address of the 6LBR because it knows the address of the root via the 412 DODAGID in the DIO messages. 414 +-------------------+-----+------+------+ 415 | Header | 6LN | 6LR | 6LBR | 416 +-------------------+-----+------+------+ 417 | Inserted headers | RPI | -- | -- | 418 | Removed headers | -- | -- | RPI | 419 | Re-added headers | -- | -- | -- | 420 | Modified headers | -- | RPI | -- | 421 | Untouched headers | -- | -- | -- | 422 +-------------------+-----+------+------+ 424 Storing: Summary of the use of headers from RPL-aware-leaf to root 426 5.2. Example of Flow from root to RPL-aware-leaf 428 In this case the flow comprises: 430 root (6LBR) --> 6LR1,... --> 6LRN --> RPL-aware-leaf (6LN) 432 In this case the 6LBR inserts RPI header and sends the packet down, 433 the 6LR is going to increment the rank in RPI (examines instanceID 434 for multiple tables), the packet is processed in 6LN and RPI removed. 436 No IP-in-IP header is required. 438 +-------------------+------+-------+------+ 439 | Header | 6LBR | 6LR | 6LN | 440 +-------------------+------+-------+------+ 441 | Inserted headers | RPI | -- | -- | 442 | Removed headers | -- | -- | RPI | 443 | Re-added headers | -- | -- | -- | 444 | Modified headers | -- | RPI | -- | 445 | Untouched headers | -- | -- | -- | 446 +-------------------+------+-------+------+ 448 Storing: Summary of the use of headers from root to RPL-aware-leaf 450 5.3. Example of Flow from root to not-RPL-aware-leaf 452 In this case the flow comprises: 454 root (6LBR) --> 6LR1,... --> 6LRN --> not-RPL-aware-leaf (IPv6) 456 As the RPI extension can be ignored by the not-RPL-aware leaf, this 457 situation is identical to the previous scenario. 459 +-------------------+------+-----------+----------------+ 460 | Header | 6LBR | 6LR(1..N) | 6LN | 461 +-------------------+------+-----------+----------------+ 462 | Inserted headers | RPI | -- | -- | 463 | Removed headers | -- | -- | -- | 464 | Re-added headers | -- | -- | -- | 465 | Modified headers | -- | RPI | -- | 466 | Untouched headers | -- | -- | RPI (Ignored) | 467 +-------------------+------+-----------+----------------+ 469 Storing: Summary of the use of headers from root to not-RPL-aware- 470 leaf 472 5.4. Example of Flow from not-RPL-aware-leaf to root 474 In this case the flow comprises: 476 not-RPL-aware-leaf (IPv6) --> 6LR1,... --> 6LRN --> root (6LBR) 478 When the packet arrives from IPv6 node to 6LR, the 6LR1 will insert 479 an RPI header, encapsuladed in a IPv6-in-IPv6 header. The IPv6-in- 480 IPv6 header can be addressed to the next hop, or to the root. The 481 root removes the header and processes the packet. 483 +------------+------+---------------+---------------+---------------+ 484 | Header | IPv6 | 6LR1 | 6LRN | 6LBR | 485 +------------+------+---------------+---------------+---------------+ 486 | Inserted | -- | IP-in-IP(RPI) | -- | -- | 487 | headers | | | | | 488 | Removed | -- | -- | -- | IP-in-IP(RPI) | 489 | headers | | | | | 490 | Re-added | -- | -- | -- | -- | 491 | headers | | | | | 492 | Modified | -- | -- | IP-in-IP(RPI) | -- | 493 | headers | | | | | 494 | Untouched | -- | -- | -- | -- | 495 | headers | | | | | 496 +------------+------+---------------+---------------+---------------+ 498 Storing: Summary of the use of headers from not-RPL-aware-leaf to 499 root 501 5.5. Example of Flow from RPL-aware-leaf to Internet 503 RPL information from RFC 6553 MAY go out to Internet as it will be 504 ignored by nodes which have not been configured to be RPI aware. 506 In this case the flow comprises: 508 RPL-aware-leaf (6LN) --> 6LR1,... --> 6LRN --> root (6LBR) --> 509 Internet 511 No IP-in-IP header is required. 513 +-------------------+------+-----------+------+----------------+ 514 | Header | 6LN | 6LR(1..N) | 6LBR | Internet | 515 +-------------------+------+-----------+------+----------------+ 516 | Inserted headers | RPI | -- | -- | -- | 517 | Removed headers | -- | -- | -- | -- | 518 | Re-added headers | -- | -- | -- | -- | 519 | Modified headers | -- | RPI | -- | -- | 520 | Untouched headers | -- | -- | -- | RPI (Ignored) | 521 +-------------------+------+-----------+------+----------------+ 523 Storing: Summary of the use of headers from RPL-aware-leaf to 524 Internet 526 5.6. Example of Flow from Internet to RPL-aware-leaf 528 In this case the flow comprises: 530 Internet --> root (6LBR) --> 6LR1,... --> 6LRN --> RPL-aware-leaf 531 (6LN) 533 When the packet arrives from Internet to 6LBR the RPI header is added 534 in a outer IPv6-in-IPv6 header and sent to 6LR, which modifies the 535 rank in the RPI. When the packet arrives at 6LN the RPI header is 536 removed and the packet processed. 538 +----------+---------+--------------+---------------+---------------+ 539 | Header | Interne | 6LBR | 6LR(1...N) | 6LN | 540 | | t | | | | 541 +----------+---------+--------------+---------------+---------------+ 542 | Inserted | -- | IP-in- | -- | -- | 543 | headers | | IP(RPI) | | | 544 | Removed | -- | -- | -- | IP-in-IP(RPI) | 545 | headers | | | | | 546 | Re-added | -- | -- | -- | -- | 547 | headers | | | | | 548 | Modified | -- | -- | IP-in-IP(RPI) | -- | 549 | headers | | | | | 550 | Untouche | -- | -- | -- | -- | 551 | d | | | | | 552 | headers | | | | | 553 +----------+---------+--------------+---------------+---------------+ 555 Storing: Summary of the use of headers from Internet to RPL-aware- 556 leaf 558 5.7. Example of Flow from not-RPL-aware-leaf to Internet 560 In this case the flow comprises: 562 not-RPL-aware-leaf (IPv6) --> 6LR1,... --> 6LRN --> root (6LBR) --> 563 Internet 565 The 6LR1 node will add an IP-in-IP(RPI) header addressed either to 566 the root, or hop-by-hop such that the root can remove the RPI header 567 before passing upwards. 569 The originating node will ideally leave the IPv6 flow label as zero 570 so that it can be better compressed through the LLN, and the 6LBR 571 will set the flow label to a non-zero value when sending to the 572 Internet. 574 +---------+-----+-------------+-------------+-------------+---------+ 575 | Header | IPv | 6LR1 | 6LBN | 6LBR | Interne | 576 | | 6 | | | | t | 577 +---------+-----+-------------+-------------+-------------+---------+ 578 | Inserte | -- | IP-in- | -- | -- | -- | 579 | d | | IP(RPI) | | | | 580 | headers | | | | | | 581 | Removed | -- | -- | -- | IP-in- | -- | 582 | headers | | | | IP(RPI) | | 583 | Re- | -- | -- | -- | -- | -- | 584 | added | | | | | | 585 | headers | | | | | | 586 | Modifie | -- | -- | IP-in- | -- | -- | 587 | d | | | IP(RPI) | | | 588 | headers | | | | | | 589 | Untouch | -- | -- | -- | -- | -- | 590 | ed | | | | | | 591 | headers | | | | | | 592 +---------+-----+-------------+-------------+-------------+---------+ 594 Storing: Summary of the use of headers from not-RPL-aware-leaf to 595 Internet 597 5.8. Example of Flow from Internet to non-RPL-aware-leaf 599 In this case the flow comprises: 601 Internet --> root (6LBR) --> 6LR1,... --> 6LRN --> not-RPL-aware-leaf 602 (IPv6) 604 The 6LBR will have to add an RPI header within an IP-in-IP header. 605 The IP-in-IP can be addressed to the not-RPL-aware-leaf, leaving the 606 RPI inside. 608 The 6LBR MAY set the flow label on the inner IP-in-IP header to zero 609 in order to aid in compression, as the packet will not emerge again 610 from the LLN. 612 +-----------+----------+---------------+---------------+------------+ 613 | Header | Internet | 6LBR | 6LR(1...N) | IPv6 | 614 +-----------+----------+---------------+---------------+------------+ 615 | Inserted | -- | IP-in-IP(RPI) | -- | -- | 616 | headers | | | | | 617 | Removed | -- | -- | IP-in-IP(RPI) | -- | 618 | headers | | | | | 619 | Re-added | -- | -- | -- | -- | 620 | headers | | | | | 621 | Modified | -- | -- | IP-in-IP(RPI) | -- | 622 | headers | | | | | 623 | Untouched | -- | -- | -- | RPI | 624 | headers | | | | (Ignored) | 625 +-----------+----------+---------------+---------------+------------+ 627 Storing: Summary of the use of headers from Internet to non-RPL- 628 aware-leaf 630 5.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf 632 In [RFC6550] RPL allows a simple one-hop optimization for both 633 storing and non-storing networks. A node may send a packet destined 634 to a one-hop neighbor directly to that node. Section 9 in [RFC6550]. 636 In this case the flow comprises: 638 6LN --> 6LR1 --> common parent (6LRx) --> 6LRN --> 6LN 640 This case is assumed in the same RPL Domain. In the common parent, 641 the direction of RPI is changed (from increasing to decreasing the 642 rank). 644 While the 6LR nodes will update the RPI, no node needs to add or 645 remove the RPI, so no IP-in-IP headers are necessary. This may be 646 done regardless of where the destination is, as the included RPI will 647 be ignored by the receiver. 649 +------------+-------+---------------+---------------+------+-------+ 650 | Header | 6LN | 6LR1 | 6LRx (common | 6LRN | 6LN | 651 | | src | | parent) | | dst | 652 +------------+-------+---------------+---------------+------+-------+ 653 | Inserted | RPI | -- | -- | -- | -- | 654 | headers | | | | | | 655 | Removed | -- | -- | -- | -- | RPI | 656 | headers | | | | | | 657 | Re-added | -- | -- | -- | -- | -- | 658 | headers | | | | | | 659 | Modified | -- | RPI | RPI | -- | -- | 660 | headers | | (decreasing | (increasing | | | 661 | | | rank) | rank) | | | 662 | Untouched | -- | -- | -- | -- | -- | 663 | headers | | | | | | 664 +------------+-------+---------------+---------------+------+-------+ 666 Storing: Summary of the use of headers for RPL-aware-leaf to RPL- 667 aware-leaf 669 5.10. Example of Flow from RPL-aware-leaf to non-RPL-aware-leaf 671 In this case the flow comprises: 673 6LN --> 6LR1 --> common parent (6LRx) --> 6LRN --> not-RPL-aware 6LN 674 (IPv6) 676 This situation is identical to the previous situation Section 5.9 677 +-----------+-----+-------------+-------------+------+--------------+ 678 | Header | 6LN | 6LR1 | 6LRx | 6LRN | IPv6 | 679 | | src | | (common | | | 680 | | | | parent) | | | 681 +-----------+-----+-------------+-------------+------+--------------+ 682 | Inserted | RPI | -- | -- | -- | -- | 683 | headers | | | | | | 684 | Removed | -- | -- | -- | -- | RPI | 685 | headers | | | | | | 686 | Re-added | -- | -- | -- | -- | -- | 687 | headers | | | | | | 688 | Modified | -- | RPI | RPI | -- | -- | 689 | headers | | (decreasing | (increasing | | | 690 | | | rank) | rank) | | | 691 | Untouched | -- | -- | -- | -- | RPI(Ignored) | 692 | headers | | | | | | 693 +-----------+-----+-------------+-------------+------+--------------+ 695 Storing: Summary of the use of headers for RPL-aware-leaf to RPL- 696 aware-leaf 698 5.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 700 In this case the flow comprises: 702 not-RPL-aware 6LN (IPv6) --> 6LR1 --> common parent (6LRx) --> 6LRN 703 --> 6LN 705 The 6LR1 receives the packet from the the IPv6 node and inserts and 706 the RPI header encapsulated in IPv6-in-IPv6 header. The IP-in-IP 707 header is addressed to the destination 6LN. 709 +--------+------+------------+------------+------------+------------+ 710 | Header | IPv6 | 6LR1 | common | 6LRn | 6LN | 711 | | | | parent | | | 712 | | | | (6LRx) | | | 713 +--------+------+------------+------------+------------+------------+ 714 | Insert | -- | IP-in- | -- | -- | -- | 715 | ed hea | | IP(RPI) | | | | 716 | ders | | | | | | 717 | Remove | -- | -- | -- | -- | IP-in- | 718 | d head | | | | | IP(RPI) | 719 | ers | | | | | | 720 | Re- | -- | -- | -- | -- | -- | 721 | added | | | | | | 722 | header | | | | | | 723 | s | | | | | | 724 | Modifi | -- | -- | IP-in- | IP-in- | -- | 725 | ed hea | | | IP(RPI) | IP(RPI) | | 726 | ders | | | | | | 727 | Untouc | -- | -- | -- | -- | -- | 728 | hed he | | | | | | 729 | aders | | | | | | 730 +--------+------+------------+------------+------------+------------+ 732 Storing: Summary of the use of headers from not-RPL-aware-leaf to 733 RPL-aware-leaf 735 5.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-leaf 737 In this case the flow comprises: 739 not-RPL-aware 6LN (IPv6 src)--> 6LR1 --> 6LR2 --> root (6LBR) --> 740 6LRn --> not-RPL-aware 6LN (IPv6 dst) 742 This flow is identical to Section 5.11 744 The 6LR receives the packet from the the IPv6 node and inserts the 745 RPI header (RPIa) encapsulated in IPv6-in-IPv6 header. The IPv6-in- 746 IPv6 header is addressed to the 6LBR. The 6LBR remove the IPv6-in- 747 IPv6 header and insert another one (RPIb) with destination to 6LRn 748 node. 750 +-------+-----+-----------+-----------+-----------+-----------+-----+ 751 | Heade | IPv | 6LR1 | 6LR2 | 6LBR | 6LRn | IPv | 752 | r | 6 | | | | | 6 | 753 | | src | | | | | dst | 754 +-------+-----+-----------+-----------+-----------+-----------+-----+ 755 | Inser | -- | IP-in- | -- | IP-in- | -- | -- | 756 | ted h | | IP(RPIa) | | IP(RPIb) | | | 757 | eader | | | | | | | 758 | s | | | | | | | 759 | Remov | -- | -- | -- | -- | -- | -- | 760 | ed he | | | | | | | 761 | aders | | | | | | | 762 | Re- | -- | -- | -- | -- | IP-in- | -- | 763 | added | | | | | IP(RPIb) | | 764 | heade | | | | | | | 765 | rs | | | | | | | 766 | Modif | -- | -- | IP-in- | -- | IP-in- | -- | 767 | ied h | | | IP(RPIa) | | IP(RPIb) | | 768 | eader | | | | | | | 769 | s | | | | | | | 770 | Untou | -- | -- | -- | -- | -- | -- | 771 | ched | | | | | | | 772 | heade | | | | | | | 773 | rs | | | | | | | 774 +-------+-----+-----------+-----------+-----------+-----------+-----+ 776 Storing: Summary of the use of headers from not-RPL-aware-leaf to 777 non-RPL-aware-leaf 779 6. Non Storing mode 780 +--------------+------+------+-----------+---------------+ 781 | Use Case | RPI | RH3 | IP-in-IP | IP-in-IP dst | 782 +--------------+------+------+-----------+---------------+ 783 | Raf to root | Yes | No | No | -- | 784 | root to Raf | Opt | Yes | No | -- | 785 | root to ~Raf | No | Yes | Yes | 6LR | 786 | ~Raf to root | Yes | No | Yes | root | 787 | Raf to Int | Yes | No | Yes | root | 788 | Int to Raf | Opt | Yes | Yes | dst | 789 | ~Raf to Int | Yes | No | Yes | root | 790 | Int to ~Raf | Opt | Yes | Yes | 6LR | 791 | Raf to Raf | Yes | Yes | Yes | root/dst | 792 | Raf to ~Raf | Yes | Yes | Yes | root/6LR | 793 | ~Raf to Raf | Yes | Yes | Yes | root/6LN | 794 | ~Raf to ~Raf | Yes | Yes | Yes | root/6LR | 795 +--------------+------+------+-----------+---------------+ 797 Table 2: Headers needed in Non-Storing mode: RPI, RH3, IP-in-IP 798 encapsulation 800 6.1. Example of Flow from RPL-aware-leaf to root 802 In non-storing mode the leaf node uses default routing to send 803 traffic to the root. The RPI header must be included to avoid/detect 804 loops. 806 RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) 808 This situation is the same case as storing mode. 810 +-------------------+-----+------+------+ 811 | Header | 6LN | 6LR | 6LBR | 812 +-------------------+-----+------+------+ 813 | Inserted headers | RPI | -- | -- | 814 | Removed headers | -- | -- | RPI | 815 | Re-added headers | -- | -- | -- | 816 | Modified headers | -- | RPI | -- | 817 | Untouched headers | -- | -- | -- | 818 +-------------------+-----+------+------+ 820 Non Storing: Summary of the use of headers from RPL-aware-leaf to 821 root 823 6.2. Example of Flow from root to RPL-aware-leaf 825 In this case the flow comprises: 827 root (6LBR)--> 6LR --> RPL-aware-leaf (6LN) 828 The 6LBR will insert an RH3, and may optionally insert an RPI header. 829 No IP-in-IP header is necessary as the traffic originates with an RPL 830 aware node, the 6LBR. The destination is known to RPL-aware because, 831 the root knows the whole topology in non-storing mode. 833 +-------------------+-----------------+------+----------+ 834 | Header | 6LBR | 6LR | 6LN | 835 +-------------------+-----------------+------+----------+ 836 | Inserted headers | (opt: RPI), RH3 | -- | -- | 837 | Removed headers | -- | -- | RH3,RPI | 838 | Re-added headers | -- | -- | -- | 839 | Modified headers | -- | RH3 | -- | 840 | Untouched headers | -- | -- | -- | 841 +-------------------+-----------------+------+----------+ 843 Non Storing: Summary of the use of headers from root to RPL-aware- 844 leaf 846 6.3. Example of Flow from root to not-RPL-aware-leaf 848 In this case the flow comprises: 850 root (6LBR)--> 6LR1...-->6LRn --> not-RPL-aware-leaf (IPv6) 852 In 6LBR the RH3 is added, modified in each intermediate 6LR (6LR1 and 853 so on) and it is fully consumed in the last 6LR (6LRn), but left 854 there. If RPI is left present, the IPv6 node which does not 855 understand it will ignore it (following 2460bis), thus encapsulation 856 is not necesary. Due the complete knowledge of the topology at the 857 root, the 6LBR is able to address the IP-in-IP header to the last 858 6LR. 860 +----------------+--------------+--------------+-------------+------+ 861 | Header | 6LBR | 6LR1 | 6LRn | IPv6 | 862 +----------------+--------------+--------------+-------------+------+ 863 | Inserted | (opt: RPI), | -- | -- | -- | 864 | headers | RH3 | | | | 865 | Removed | -- | RH3 | -- | -- | 866 | headers | | | | | 867 | Re-added | -- | -- | -- | -- | 868 | headers | | | | | 869 | Modified | -- | (opt: RPI), | (opt: RPI), | -- | 870 | headers | | RH3 | RH3 | | 871 | Untouched | -- | -- | -- | RPI | 872 | headers | | | | | 873 +----------------+--------------+--------------+-------------+------+ 875 Non Storing: Summary of the use of headers from root to not-RPL- 876 aware-leaf 878 6.4. Example of Flow from not-RPL-aware-leaf to root 880 In this case the flow comprises: 882 IPv6-node --> 6LR1 ...--> 6LRn --> root (6LBR) 884 In this case the RPI is added by the first 6LR (6LR1), encapsulated 885 in an IP-in-IP header, and is modified in the followings 6LRs. The 886 RPI and entire packet is consumed by the root. 888 +------------+------+---------------+---------------+---------------+ 889 | Header | IPv6 | 6LR1 | 6LR2 | 6LBR | 890 +------------+------+---------------+---------------+---------------+ 891 | Inserted | -- | IP-in-IP(RPI) | -- | -- | 892 | headers | | | | | 893 | Removed | -- | -- | -- | IP-in-IP(RPI) | 894 | headers | | | | | 895 | Re-added | -- | -- | -- | -- | 896 | headers | | | | | 897 | Modified | -- | IP-in-IP(RPI) | IP-in-IP(RPI) | -- | 898 | headers | | | | | 899 | Untouched | -- | -- | -- | -- | 900 | headers | | | | | 901 +------------+------+---------------+---------------+---------------+ 903 Non Storing: Summary of the use of headers from not-RPL-aware-leaf to 904 root 906 6.5. Example of Flow from RPL-aware-leaf to Internet 908 In this case the flow comprises: 910 RPL-aware-leaf (6LN) --> 6LR1 ...--> 6LRn --> root (6LBR) --> 911 Internet 913 This case is identical to storing-mode case. 915 The IPv6 flow label should be set to zero to aid in compression, and 916 the 6LBR will set it to a non-zero value when sending towards the 917 Internet. 919 +-------------------+------+-----------+------+----------------+ 920 | Header | 6LN | 6LR(1..N) | 6LBR | Internet | 921 +-------------------+------+-----------+------+----------------+ 922 | Inserted headers | RPI | -- | -- | -- | 923 | Removed headers | -- | -- | -- | -- | 924 | Re-added headers | -- | -- | -- | -- | 925 | Modified headers | -- | RPI | -- | -- | 926 | Untouched headers | -- | -- | -- | RPI (Ignored) | 927 +-------------------+------+-----------+------+----------------+ 929 Non Storing: Summary of the use of headers from RPL-aware-leaf to 930 Internet 932 6.6. Example of Flow from Internet to RPL-aware-leaf 934 In this case the flow comprises: 936 Internet --> root (6LBR) --> 6LR1...--> 6LRn --> RPL-aware-leaf (6LN) 938 The 6LBR must add an RH3 header. As the 6LBR will know the path and 939 address of the target node, it can address the IP-in-IP header to 940 that node. The 6LBR will zero the flow label upon entry in order to 941 aid compression. 943 The RPI may be added or not, it is optional. 945 +--------+-------+----------------+----------------+----------------+ 946 | Header | Inter | 6LBR | 6LR | 6LN | 947 | | net | | | | 948 +--------+-------+----------------+----------------+----------------+ 949 | Insert | -- | IP-in-IP(RH3,o | -- | -- | 950 | ed hea | | pt:RPI) | | | 951 | ders | | | | | 952 | Remove | -- | -- | -- | IP-in-IP(RH3,o | 953 | d head | | | | pt:RPI) | 954 | ers | | | | | 955 | Re- | -- | -- | -- | -- | 956 | added | | | | | 957 | header | | | | | 958 | s | | | | | 959 | Modifi | -- | -- | IP-in-IP(RH3,o | -- | 960 | ed hea | | | pt:RPI) | | 961 | ders | | | | | 962 | Untouc | -- | -- | -- | -- | 963 | hed he | | | | | 964 | aders | | | | | 965 +--------+-------+----------------+----------------+----------------+ 967 Non Storing: Summary of the use of headers from Internet to RPL- 968 aware-leaf 970 6.7. Example of Flow from not-RPL-aware-leaf to Internet 972 In this case the flow comprises: 974 not-RPL-aware-leaf (IPv6) --> 6LR1..--> 6LRn --> root (6LBR) --> 975 Internet 977 In this case the flow label is recommended to be zero in the IPv6 978 node. As RPL headers are added in the IPv6 node, the first 6LN will 979 add an RPI header inside a new IP-in-IP header. The IP-in-IP header 980 will be addressed to the root. This case is identical to the 981 storing-mode case (Section 5.7). 983 +---------+-----+-------------+-------------+-------------+---------+ 984 | Header | IPv | 6LR1 | 6LRn | 6LBR | Interne | 985 | | 6 | | | | t | 986 +---------+-----+-------------+-------------+-------------+---------+ 987 | Inserte | -- | IP-in- | -- | -- | -- | 988 | d | | IP(RPI) | | | | 989 | headers | | | | | | 990 | Removed | -- | -- | -- | IP-in- | -- | 991 | headers | | | | IP(RPI) | | 992 | Re- | -- | -- | -- | -- | -- | 993 | added | | | | | | 994 | headers | | | | | | 995 | Modifie | -- | -- | IP-in- | -- | -- | 996 | d | | | IP(RPI) | | | 997 | headers | | | | | | 998 | Untouch | -- | -- | -- | -- | -- | 999 | ed | | | | | | 1000 | headers | | | | | | 1001 +---------+-----+-------------+-------------+-------------+---------+ 1003 Non Storing: Summary of the use of headers from not-RPL-aware-leaf to 1004 Internet 1006 6.8. Example of Flow from Internet to non-RPL-aware-leaf 1008 In this case the flow comprises: 1010 Internet --> root (6LBR) --> 6LR1...--> 6LRn --> not-RPL-aware-leaf 1011 (IPv6) 1013 The 6LBR must add an RH3 header inside an IP-in-IP header. The 6LBR 1014 will know the path, and will recognize that the final node is not an 1015 RPL capable node as it will have received the connectivity DAO from 1016 the nearest 6LR. The 6LBR can therefore make the IP-in-IP header 1017 destination be the last 6LR. The 6LBR will set to zero the flow 1018 label upon entry in order to aid compression. 1020 +--------+-------+-----------------+------------+------------+------+ 1021 | Header | Inter | 6LBR | 6LR1 | 6LRn | IPv6 | 1022 | | net | | | | | 1023 +--------+-------+-----------------+------------+------------+------+ 1024 | Insert | -- | IP-in- | -- | -- | -- | 1025 | ed hea | | IP(RH3,opt:RPI) | | | | 1026 | ders | | | | | | 1027 | Remove | -- | -- | -- | IP-in- | -- | 1028 | d head | | | | IP(RH3, | | 1029 | ers | | | | RPI) | | 1030 | Re- | -- | -- | -- | -- | -- | 1031 | added | | | | | | 1032 | header | | | | | | 1033 | s | | | | | | 1034 | Modifi | -- | -- | IP-in- | IP-in- | -- | 1035 | ed hea | | | IP(RH3, | IP(RH3, | | 1036 | ders | | | RPI) | RPI) | | 1037 | Untouc | -- | -- | -- | -- | RPI | 1038 | hed he | | | | | | 1039 | aders | | | | | | 1040 +--------+-------+-----------------+------------+------------+------+ 1042 NonStoring: Summary of the use of headers from Internet to non-RPL- 1043 aware-leaf 1045 6.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf 1047 In this case the flow comprises: 1049 6LN --> 6LR1 --> root (6LBR) --> 6LRN --> 6LN 1051 This case involves only nodes in same RPL Domain. The originating 1052 node will add an RPI header to the original packet, and send the 1053 packet upwards. 1055 The originating node SHOULD put the RPI into an IP-in-IP header 1056 addressed to the root, so that the 6LBR can remove that header. If 1057 it does not, then additional resources are wasted on the way down to 1058 carry the useless RPI option. 1060 The 6LBR will need to insert an RH3 header, which requires that it 1061 add an IP-in-IP header. It SHOULD be able to remove the RPI, as it 1062 was contained in an IP-in-IP header addressed to it. Otherwise, 1063 there MAY be an RPI header buried inside the inner IP header, which 1064 should get ignored. 1066 Networks that use the RPL P2P extension [RFC6997] are essentially 1067 non-storing DODAGs and fall into this scenario or scenario 1068 Section 6.2, with the originating node acting as 6LBR. 1070 +---------+-------------+------+--------------+------+--------------+ 1071 | Header | 6LN src | 6LR1 | 6LBR | 6LRN | 6LN dst | 1072 +---------+-------------+------+--------------+------+--------------+ 1073 | Inserte | IP-in- | -- | IP-in-IP(RH3 | -- | -- | 1074 | d | IP(RPI1) | | to 6LN, opt | | | 1075 | headers | | | RPI2) | | | 1076 | Removed | -- | -- | IP-in- | -- | IP-in- | 1077 | headers | | | IP(RPI1) | | IP(RH3, opt | 1078 | | | | | | RPI2) | 1079 | Re- | -- | -- | -- | -- | -- | 1080 | added | | | | | | 1081 | headers | | | | | | 1082 | Modifie | -- | -- | -- | -- | -- | 1083 | d | | | | | | 1084 | headers | | | | | | 1085 | Untouch | -- | -- | -- | -- | -- | 1086 | ed | | | | | | 1087 | headers | | | | | | 1088 +---------+-------------+------+--------------+------+--------------+ 1090 Non Storing: Summary of the use of headers for RPL-aware-leaf to RPL- 1091 aware-leaf 1093 6.10. Example of Flow from RPL-aware-leaf to not-RPL-aware-leaf 1095 In this case the flow comprises: 1097 6LN --> 6LR1 --> root (6LBR) --> 6LRn --> not-RPL-aware (IPv6) 1099 As in the previous case, the 6LN will insert an RPI (RPI1) header 1100 which MUST be in an IP-in-IP header addressed to the root so that the 1101 6LBR can remove this RPI. The 6LBR will then insert an RH3 inside a 1102 new IP-in-IP header addressed to the 6LN destination node. The RPI 1103 is optional from 6LBR to 6LRn (RPI2). 1105 +--------+------------+------------+------------+------------+------+ 1106 | Header | 6LN | 6LR1 | 6LBR | 6LRn | IPv6 | 1107 +--------+------------+------------+------------+------------+------+ 1108 | Insert | IP-in- | -- | IP-in- | -- | -- | 1109 | ed hea | IP(RPI1) | | IP(RH3, | | | 1110 | ders | | | opt RPI2) | | | 1111 | Remove | -- | -- | IP-in- | IP-in- | -- | 1112 | d head | | | IP(RPI1) | IP(RH3, | | 1113 | ers | | | | opt RPI2) | | 1114 | Re- | -- | -- | -- | -- | -- | 1115 | added | | | | | | 1116 | header | | | | | | 1117 | s | | | | | | 1118 | Modifi | -- | IP-in- | -- | IP-in- | -- | 1119 | ed hea | | IP(RPI1) | | IP(RH3, | | 1120 | ders | | | | opt RPI2) | | 1121 | Untouc | -- | -- | -- | -- | opt | 1122 | hed he | | | | | RPI2 | 1123 | aders | | | | | | 1124 +--------+------------+------------+------------+------------+------+ 1126 Non Storing: Summary of the use of headers from RPL-aware-leaf to 1127 not-RPL-aware-leaf 1129 6.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 1131 In this case the flow comprises: 1133 not-RPL-aware 6LN (IPv6) --> 6LR1 --> root (6LBR) --> 6LRn --> 6LN 1135 This scenario is mostly identical to the previous one. The RPI is 1136 added by the first 6LR (6LR1) inside an IP-in-IP header addressed to 1137 the root. The 6LBR will remove this RPI, and add it's own IP-in-IP 1138 header containing an RH3 header and optional RPI (RPI2). 1140 +--------+-----+------------+-------------+------------+------------+ 1141 | Header | IPv | 6LR1 | 6LBR | 6LRn | 6LN | 1142 | | 6 | | | | | 1143 +--------+-----+------------+-------------+------------+------------+ 1144 | Insert | -- | IP-in- | IP-in- | -- | -- | 1145 | ed hea | | IP(RPI1) | IP(RH3, opt | | | 1146 | ders | | | RPI2) | | | 1147 | Remove | -- | -- | IP-in- | -- | IP-in- | 1148 | d head | | | IP(RPI1) | | IP(RH3, | 1149 | ers | | | | | opt RPI2) | 1150 | Re- | -- | -- | -- | -- | -- | 1151 | added | | | | | | 1152 | header | | | | | | 1153 | s | | | | | | 1154 | Modifi | -- | -- | -- | IP-in- | -- | 1155 | ed hea | | | | IP(RH3, | | 1156 | ders | | | | opt RPI2) | | 1157 | Untouc | -- | -- | -- | -- | -- | 1158 | hed he | | | | | | 1159 | aders | | | | | | 1160 +--------+-----+------------+-------------+------------+------------+ 1162 Non Storing: Summary of the use of headers from not-RPL-aware-leaf to 1163 RPL-aware-leaf 1165 6.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-leaf 1167 In this case the flow comprises: 1169 not-RPL-aware 6LN (IPv6 src)--> 6LR1 --> root (6LBR) --> 6LRn --> 1170 not-RPL-aware (IPv6 dst) 1172 This scenario is the combination of the previous two cases. 1174 +---------+-----+--------------+--------------+--------------+------+ 1175 | Header | IPv | 6LR1 | 6LBR | 6LRn | IPv6 | 1176 | | 6 | | | | dst | 1177 | | src | | | | | 1178 +---------+-----+--------------+--------------+--------------+------+ 1179 | Inserte | -- | IP-in- | IP-in- | -- | -- | 1180 | d | | IP(RPI1) | IP(RH3) | | | 1181 | headers | | | | | | 1182 | Removed | -- | -- | IP-in- | IP-in- | -- | 1183 | headers | | | IP(RPI1) | IP(RH3, opt | | 1184 | | | | | RPI2) | | 1185 | Re- | -- | -- | -- | -- | -- | 1186 | added | | | | | | 1187 | headers | | | | | | 1188 | Modifie | -- | -- | -- | -- | -- | 1189 | d | | | | | | 1190 | headers | | | | | | 1191 | Untouch | -- | -- | -- | -- | -- | 1192 | ed | | | | | | 1193 | headers | | | | | | 1194 +---------+-----+--------------+--------------+--------------+------+ 1196 Non Storing: Summary of the use of headers from not-RPL-aware-leaf to 1197 not-RPL-aware-leaf 1199 7. Observations about the cases 1201 7.1. Storing mode 1203 [I-D.ietf-roll-routing-dispatch] shows that this hop-by-hop IP-in-IP 1204 header can be compressed down to {TBD} bytes. 1206 There are potential significant advantages to having a single code 1207 path that always processes IP-in-IP headers with no options. 1209 Thanks to the relaxation of the RFC2406 rule about discarding unknown 1210 Hop-by-Hop options, there is no longer any uncertainty about when to 1211 use an IPIP header in the storing mode case. The RPI header SHOULD 1212 always be added when 6LRs originate packets (without IPIP headers), 1213 and IPIP headers should always be added (addressed to the root when 1214 on the way up, to the end-host when on the way down) when a 6LR finds 1215 it needs to insert an RPI header. (XXX - this is a problem for 1216 storing mode optimization) 1218 In order to support the above two cases with full generality, the 1219 different situations (always do IP-in-IP vs never use IP-in-IP) 1220 should be signaled in the RPL protocol itself. 1222 7.2. Non-Storing mode 1224 In the non-storing case, dealing with non-RPL aware leaf nodes is 1225 much easier as the 6LBR (DODAG root) has complete knowledge about the 1226 connectivity of all DODAG nodes, and all traffic flows through the 1227 root node. 1229 The 6LBR can recognize non-RPL aware leaf nodes because it will 1230 receive a DAO about that node from the 6LN immediately above that 1231 node. This means that the non-storing mode case can avoid ever using 1232 hop-by-hop IP-in-IP headers. 1234 [I-D.ietf-roll-routing-dispatch] shows how the destination=root, and 1235 destination=6LN IP-in-IP header can be compressed down to {TBD} 1236 bytes. 1238 Unlike in the storing mode case, there is no need for all nodes to 1239 know about the existence of non-RPL aware nodes. Only the 6LBR needs 1240 to change when there are non-RPL aware nodes. Further, in the non- 1241 storing case, the 6LBR is informed by the DAOs when there are non-RPL 1242 aware nodes. 1244 8. 6LoRH Compression cases 1246 The [I-D.ietf-roll-routing-dispatch] proposes a compression method 1247 for RPI, RH3 and IPv6-in-IPv6. 1249 In Storing Mode, for the examples of Flow from RPL-aware-leaf to non- 1250 RPL-aware-leaf and non-RPL-aware-leaf to non-RPL-aware-leaf comprise 1251 an IP-in-IP and RPI compression headers. The type of this case is 1252 critical since IP-in-IP is encapsulating a RPI header. 1254 +--+-----+---+--------------+-----------+-------------+-------------+ 1255 |1 | 0|0 |TSE| 6LoRH Type 6 | Hop Limit | RPI - 6LoRH | LOWPAN IPHC | 1256 +--+-----+---+--------------+-----------+-------------+-------------+ 1258 Figure 3: Critical IP-in-IP (RPI). 1260 9. IANA Considerations 1262 There are no IANA considerations related to this document. 1264 10. Security Considerations 1266 The security considerations covering of [RFC6553] and [RFC6554] apply 1267 when the packets get into RPL Domain. 1269 11. Acknowledgments 1271 This work is partially funded by the FP7 Marie Curie Initial Training 1272 Network (ITN) METRICS project (grant agreement No. 607728). 1274 The authors would like to acknowledge the review, feedback, and 1275 comments of Robert Cragie, Simon Duquennoy, Cenk Guendogan, Peter van 1276 der Stok, Xavier Vilajosana and Thomas Watteyne. 1278 12. References 1280 12.1. Normative References 1282 [I-D.ietf-6man-rfc2460bis] 1283 Hinden, R., "Internet Protocol, Version 6 (IPv6) 1284 Specification", draft-ietf-6man-rfc2460bis-06 (work in 1285 progress), September 2016. 1287 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1288 Requirement Levels", BCP 14, RFC 2119, 1289 DOI 10.17487/RFC2119, March 1997, 1290 . 1292 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1293 (IPv6) Specification", RFC 2460, December 1998. 1295 [RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J., 1296 Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur, 1297 JP., and R. Alexander, "RPL: IPv6 Routing Protocol for 1298 Low-Power and Lossy Networks", RFC 6550, 1299 DOI 10.17487/RFC6550, March 2012, 1300 . 1302 [RFC6553] Hui, J. and JP. Vasseur, "The Routing Protocol for Low- 1303 Power and Lossy Networks (RPL) Option for Carrying RPL 1304 Information in Data-Plane Datagrams", RFC 6553, 1305 DOI 10.17487/RFC6553, March 2012, 1306 . 1308 [RFC6554] Hui, J., Vasseur, JP., Culler, D., and V. Manral, "An IPv6 1309 Routing Header for Source Routes with the Routing Protocol 1310 for Low-Power and Lossy Networks (RPL)", RFC 6554, 1311 DOI 10.17487/RFC6554, March 2012, 1312 . 1314 12.2. Informative References 1316 [I-D.ietf-6tisch-architecture] 1317 Thubert, P., "An Architecture for IPv6 over the TSCH mode 1318 of IEEE 802.15.4", draft-ietf-6tisch-architecture-10 (work 1319 in progress), June 2016. 1321 [I-D.ietf-roll-routing-dispatch] 1322 Thubert, P., Bormann, C., Toutain, L., and R. Cragie, 1323 "6LoWPAN Routing Header", draft-ietf-roll-routing- 1324 dispatch-00 (work in progress), March 2016. 1326 [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet 1327 Control Message Protocol (ICMPv6) for the Internet 1328 Protocol Version 6 (IPv6) Specification", RFC 4443, 1329 DOI 10.17487/RFC4443, March 2006, 1330 . 1332 [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. 1333 Bormann, "Neighbor Discovery Optimization for IPv6 over 1334 Low-Power Wireless Personal Area Networks (6LoWPANs)", 1335 RFC 6775, DOI 10.17487/RFC6775, November 2012, 1336 . 1338 [RFC6997] Goyal, M., Ed., Baccelli, E., Philipp, M., Brandt, A., and 1339 J. Martocci, "Reactive Discovery of Point-to-Point Routes 1340 in Low-Power and Lossy Networks", RFC 6997, 1341 DOI 10.17487/RFC6997, August 2013, 1342 . 1344 [RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and 1345 Lossy Networks", RFC 7102, DOI 10.17487/RFC7102, January 1346 2014, . 1348 [Second6TischPlugtest] 1349 "2nd 6Tisch Plugtest", . 1352 Authors' Addresses 1354 Maria Ines Robles 1355 Ericsson 1356 Hirsalantie 11 1357 Jorvas 02420 1358 Finland 1360 Email: maria.ines.robles@ericsson.com 1362 Michael C. Richardson 1363 Sandelman Software Works 1364 470 Dawson Avenue 1365 Ottawa, ON K1Z 5V7 1366 CA 1368 Email: mcr+ietf@sandelman.ca 1369 URI: http://www.sandelman.ca/mcr/ 1371 Pascal Thubert 1372 Cisco Systems, Inc 1373 Village d'Entreprises Green Side 400, Avenue de Roumanille 1374 Batiment T3, Biot - Sophia Antipolis 06410 1375 France 1377 Email: pthubert@cisco.com