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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group F. Templin, Ed. 3 Internet-Draft The Boeing Company 4 Intended status: Standards Track A. Whyman 5 Expires: September 20, 2020 MWA Ltd c/o Inmarsat Global Ltd 6 March 19, 2020 8 Transmission of IPv6 Packets over Overlay Multilink Network (OMNI) 9 Interfaces 10 draft-templin-6man-omni-interface-05 12 Abstract 14 Mobile nodes (e.g., aircraft of various configurations, terrestrial 15 vehicles, seagoing vessels, mobile enterprise devices, etc.) 16 communicate with networked correspondents over multiple access 17 network data links and configure mobile routers to connect end user 18 networks. A multilink interface specification is therefore needed 19 for coordination with the network-based mobility service. This 20 document specifies the transmission of IPv6 packets over Overlay 21 Multilink Network (OMNI) Interfaces. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at https://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on September 20, 2020. 40 Copyright Notice 42 Copyright (c) 2020 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (https://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 58 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 59 3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 6 60 4. Overlay Multilink Network (OMNI) Interface Model . . . . . . 6 61 5. Maximum Transmission Unit (MTU) and Fragmentation . . . . . . 10 62 6. Frame Format . . . . . . . . . . . . . . . . . . . . . . . . 11 63 7. Link-Local Addresses . . . . . . . . . . . . . . . . . . . . 11 64 8. Address Mapping - Unicast . . . . . . . . . . . . . . . . . . 12 65 8.1. Sub-Options . . . . . . . . . . . . . . . . . . . . . . . 13 66 8.1.1. Pad1 . . . . . . . . . . . . . . . . . . . . . . . . 14 67 8.1.2. PadN . . . . . . . . . . . . . . . . . . . . . . . . 15 68 8.1.3. ifIndex-tuple (Type 1) . . . . . . . . . . . . . . . 15 69 8.1.4. ifIndex-tuple (Type 2) . . . . . . . . . . . . . . . 17 70 8.1.5. Register MSE ID . . . . . . . . . . . . . . . . . . . 18 71 8.1.6. Release MSE ID . . . . . . . . . . . . . . . . . . . 18 72 9. Address Mapping - Multicast . . . . . . . . . . . . . . . . . 19 73 10. Conceptual Sending Algorithm . . . . . . . . . . . . . . . . 19 74 10.1. Multiple OMNI Interfaces . . . . . . . . . . . . . . . . 19 75 11. Router Discovery and Prefix Registration . . . . . . . . . . 20 76 12. AR and MSE Resilience . . . . . . . . . . . . . . . . . . . . 22 77 13. Detecting and Responding to MSE Failures . . . . . . . . . . 23 78 14. Transition Considerations . . . . . . . . . . . . . . . . . . 23 79 15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 80 16. Security Considerations . . . . . . . . . . . . . . . . . . . 24 81 17. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 24 82 18. References . . . . . . . . . . . . . . . . . . . . . . . . . 25 83 18.1. Normative References . . . . . . . . . . . . . . . . . . 25 84 18.2. Informative References . . . . . . . . . . . . . . . . . 26 85 Appendix A. Type 1 ifIndex-tuple Traffic Classifier Preference 86 Encoding . . . . . . . . . . . . . . . . . . . . . . 28 87 Appendix B. Prefix Length Considerations . . . . . . . . . . . . 30 88 Appendix C. VDL Mode 2 Considerations . . . . . . . . . . . . . 31 89 Appendix D. Change Log . . . . . . . . . . . . . . . . . . . . . 31 90 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36 92 1. Introduction 94 Mobile Nodes (MNs) (e.g., aircraft of various configurations, 95 terrestrial vehicles, seagoing vessels, mobile enterprise devices, 96 etc.) often have multiple data links for communicating with networked 97 correspondents. These data links may have diverse performance, cost 98 and availability properties that can change dynamically according to 99 mobility patterns, flight phases, proximity to infrastructure, etc. 100 MNs coordinate their data links in a discipline known as "multilink", 101 in which a single virtual interface is configured over the underlying 102 data link interfaces. 104 The MN configures a virtual interface (termed the "Overlay Multilink 105 Network (OMNI) interface") as a thin layer over the underlying access 106 network interfaces. The OMNI interface is therefore the only 107 interface abstraction exposed to the IPv6 layer and behaves according 108 to the Non-Broadcast, Multiple Access (NBMA) interface principle, 109 while underlying access network interfaces appear as link layer 110 communication channels in the architecture. The OMNI interface 111 connects to a virtual overlay service known as the "OMNI link". The 112 OMNI link spans a worldwide Internetwork that may include private-use 113 infrastructures and/or the global public Internet itself. 115 Each MN receives a Mobile Network Prefix (MNP) for numbering 116 downstream-attached End User Networks (EUNs) independently of the 117 access network data links selected for data transport. The MN 118 performs router discovery over the OMNI interface (i.e., similar to 119 IPv6 customer edge routers [RFC7084]) and acts as a mobile router on 120 behalf of its EUNs. The router discovery process is iterated over 121 each of the OMNI interface's underlying access network data links in 122 order to register per-link parameters (see Section 11). 124 The OMNI interface provides a multilink nexus for exchanging inbound 125 and outbound traffic via the correct underlying Access Network (ANET) 126 interface(s). The IPv6 layer sees the OMNI interface as a point of 127 connection to the OMNI link. Each OMNI link has one or more 128 associated Mobility Service Prefixes (MSPs) from which OMNI link MNPs 129 are derived. If there are multiple OMNI links, the IPv6 layer will 130 see multiple OMNI interfaces. 132 The OMNI interface interacts with a network-based Mobility Service 133 (MS) through IPv6 Neighbor Discovery (ND) control message exchanges 134 [RFC4861]. The MS provides Mobility Service Endpoints (MSEs) that 135 track MN movements and represent their MNPs in a global routing or 136 mapping system. 138 This document specifies the transmission of IPv6 packets [RFC8200] 139 and MN/MS control messaging over OMNI interfaces. 141 2. Terminology 143 The terminology in the normative references applies; especially, the 144 terms "link" and "interface" are the same as defined in the IPv6 145 [RFC8200] and IPv6 Neighbor Discovery (ND) [RFC4861] specifications. 146 Also, the Protocol Constants defined in Section 10 of [RFC4861] are 147 used in their same format and meaning in this document. The terms 148 "All-Routers multicast", "All-Nodes multicast" and "Subnet-Router 149 anycast" are defined in [RFC4291] (with Link-Local scope assumed). 151 The following terms are defined within the scope of this document: 153 Mobile Node (MN) 154 an end system with multiple distinct upstream data link 155 connections that are managed together as a single logical unit. 156 The MN's data link connection parameters can change over time due 157 to, e.g., node mobility, link quality, etc. The MN further 158 connects a downstream-attached End User Network (EUN). The term 159 MN used here is distinct from uses in other documents, and does 160 not imply a particular mobility protocol. 162 End User Network (EUN) 163 a simple or complex downstream-attached mobile network that 164 travels with the MN as a single logical unit. The IPv6 addresses 165 assigned to EUN devices remain stable even if the MN's upstream 166 data link connections change. 168 Mobility Service (MS) 169 a mobile routing service that tracks MN movements and ensures that 170 MNs remain continuously reachable even across mobility events. 171 Specific MS details are out of scope for this document. 173 Mobility Service Endpoint (MSE) 174 an entity in the MS (either singluar or aggregate) that 175 coordinates the mobility events of one or more MN. 177 Mobility Service Prefix (MSP) 178 an aggregated IPv6 prefix (e.g., 2001:db8::/32) advertised to the 179 rest of the Internetwork by the MS, and from which more-specific 180 Mobile Network Prefixes (MNPs) are derived. 182 Mobile Network Prefix (MNP) 183 a longer IPv6 prefix taken from an MSP (e.g., 184 2001:db8:1000:2000::/56) and assigned to a MN. MNs sub-delegate 185 the MNP to devices located in EUNs. 187 Access Network (ANET) 188 a data link service network (e.g., an aviation radio access 189 network, satellite service provider network, cellular operator 190 network, wifi network, etc.) that connects MNs. Physical and/or 191 data link level security between the MN and ANET are assumed. 193 Access Router (AR) 194 a first-hop router in the ANET for connecting MNs to 195 correspondents in outside Internetworks. 197 ANET interface 198 a MN's attachment to a link in an ANET. 200 Internetwork (INET) 201 a connected network region with a coherent IP addressing plan that 202 provides transit forwarding services for ANET MNs and INET 203 correspondents. Examples include private enterprise networks, 204 ground domain aviation service networks and the global public 205 Internet itself. 207 INET interface 208 a node's attachment to a link in an INET. 210 OMNI link 211 a virtual overlay configured over one or more INETs and their 212 connected ANETs. An OMNI link can comprise multiple INET segments 213 joined by bridges the same as for any link; the addressing plans 214 in each segment may be mutually exclusive and managed by different 215 administrative entities. 217 OMNI interface 218 a node's attachment to an OMNI link, and configured over one or 219 more underlying ANET/INET interfaces. 221 OMNI link local address (LLA) 222 an IPv6 link-local address constructed as specified in Section 7, 223 and assigned to an OMNI interface. 225 OMNI Option 226 an IPv6 Neighbor Discovery option providing multilink parameters 227 for the OMNI interface as specified in Section 8. 229 Multilink 230 an OMNI interface's manner of managing diverse underlying data 231 link interfaces as a single logical unit. The OMNI interface 232 provides a single unified interface to upper layers, while 233 underlying data link selections are performed on a per-packet 234 basis considering factors such as DSCP, flow label, application 235 policy, signal quality, cost, etc. Multilinking decisions are 236 coordinated in both the outbound (i.e. MN to correspondent) and 237 inbound (i.e., correspondent to MN) directions. 239 L2 240 The second layer in the OSI network model. Also known as "layer- 241 2", "link-layer", "sub-IP layer", "data link layer", etc. 243 L3 244 The third layer in the OSI network model. Also known as "layer- 245 3", "network-layer", "IPv6 layer", etc. 247 3. Requirements 249 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 250 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 251 "OPTIONAL" in this document are to be interpreted as described in BCP 252 14 [RFC2119][RFC8174] when, and only when, they appear in all 253 capitals, as shown here. 255 An implementation is not required to internally use the architectural 256 constructs described here so long as its external behavior is 257 consistent with that described in this document. 259 4. Overlay Multilink Network (OMNI) Interface Model 261 An OMNI interface is a MN virtual interface configured over one or 262 more ANET interfaces, which may be physical (e.g., an aeronautical 263 radio link) or virtual (e.g., an Internet or higher-layer "tunnel"). 264 The MN receives a MNP from the MS, and coordinates with the MS 265 through IPv6 ND message exchanges. The MN uses the MNP to construct 266 a unique OMNI LLA through the algorithmic derivation specified in 267 Section 7 and assigns the LLA to the OMNI interface. 269 The OMNI interface architectural layering model is the same as in 270 [RFC7847], and augmented as shown in Figure 1. The IP layer (L3) 271 therefore sees the OMNI interface as a single network layer interface 272 with multiple underlying ANET interfaces that appear as L2 273 communication channels in the architecture. 275 +----------------------------+ 276 | Upper Layer Protocol | 277 Session-to-IP +---->| | 278 Address Binding | +----------------------------+ 279 +---->| IP (L3) | 280 IP Address +---->| | 281 Binding | +----------------------------+ 282 +---->| OMNI Interface | 283 Logical-to- +---->| (OMNI LLA) | 284 Physical | +----------------------------+ 285 Interface +---->| L2 | L2 | | L2 | 286 Binding |(IF#1)|(IF#2)| ..... |(IF#n)| 287 +------+------+ +------+ 288 | L1 | L1 | | L1 | 289 | | | | | 290 +------+------+ +------+ 292 Figure 1: OMNI Interface Architectural Layering Model 294 The OMNI virtual interface model gives rise to a number of 295 opportunities: 297 o since OMNI LLAs are uniquely derived from an MNP, no Duplicate 298 Address Detection (DAD) or Muticast Listener Discovery (MLD) 299 messaging is necessary. 301 o ANET interfaces do not require any L3 addresses (i.e., not even 302 link-local) in environments where communications are coordinated 303 entirely over the OMNI interface. (An alternative would be to 304 also assign the same OMNI LLA to all ANET interfaces.) 306 o as ANET interface properties change (e.g., link quality, cost, 307 availability, etc.), any active ANET interface can be used to 308 update the profiles of multiple additional ANET interfaces in a 309 single message. This allows for timely adaptation and service 310 continuity under dynamically changing conditions. 312 o coordinating ANET interfaces in this way allows them to be 313 represented in a unified MS profile with provisions for mobility 314 and multilink operations. 316 o exposing a single virtual interface abstraction to the IPv6 layer 317 allows for multilink operation (including QoS based link 318 selection, packet replication, load balancing, etc.) at L2 while 319 still permitting L3 traffic shaping based on, e.g., DSCP, flow 320 label, etc. 322 o L3 sees the OMNI interface as a point of connection to the OMNI 323 link; if there are multiple OMNI links (i.e., multiple MS's), L3 324 will see multiple OMNI interfaces. 326 Other opportunities are discussed in [RFC7847]. 328 Figure 2 depicts the architectural model for a MN connecting to the 329 MS via multiple independent ANETs. When an ANET interface becomes 330 active, the MN's OMNI interface sends native (i.e., unencapsulated) 331 IPv6 ND messages via the underlying ANET interface. IPv6 ND messages 332 traverse the ground domain ANETs until they reach an Access Router 333 (AR#1, AR#2, .., AR#n). The AR then coordinates with a Mobility 334 Service Endpoint (MSE#1, MSE#2, ..., MSE#m) in the INET and returns 335 an IPv6 ND message response to the MN. IPv6 ND messages traverse the 336 ANET at layer 2; hence, the Hop Limit is not decremented. 338 +--------------+ 339 | MN | 340 +--------------+ 341 |OMNI interface| 342 +----+----+----+ 343 +--------|IF#1|IF#2|IF#n|------ + 344 / +----+----+----+ \ 345 / | \ 346 / <---- Native | IP ----> \ 347 v v v 348 (:::)-. (:::)-. (:::)-. 349 .-(::ANET:::) .-(::ANET:::) .-(::ANET:::) 350 `-(::::)-' `-(::::)-' `-(::::)-' 351 +----+ +----+ +----+ 352 ... |AR#1| .......... |AR#2| ......... |AR#n| ... 353 . +-|--+ +-|--+ +-|--+ . 354 . | | | 355 . v v v . 356 . <----- Encapsulation -----> . 357 . . 358 . +-----+ (:::)-. . 359 . |MSE#2| .-(::::::::) +-----+ . 360 . +-----+ .-(::: INET :::)-. |MSE#m| . 361 . (::::: Routing ::::) +-----+ . 362 . `-(::: System :::)-' . 363 . +-----+ `-(:::::::-' . 364 . |MSE#1| +-----+ +-----+ . 365 . +-----+ |MSE#3| |MSE#4| . 366 . +-----+ +-----+ . 367 . . 368 . . 369 . <----- Worldwide Connected Internetwork ----> . 370 ........................................................... 372 Figure 2: MN/MS Coordination via Multiple ANETs 374 After the initial IPv6 ND message exchange, the MN can send and 375 receive unencapsulated IPv6 data packets over the OMNI interface. 376 OMNI interface multilink services will forward the packets via ARs in 377 the correct underlying ANETs. The AR encapsulates the packets 378 according to the capabilities provided by the MS and forwards them to 379 the next hop within the worldwide connected Internetwork via optimal 380 routes. 382 5. Maximum Transmission Unit (MTU) and Fragmentation 384 All IPv6 interfaces are REQUIRED to configure a minimum Maximum 385 Transmission Unit (MTU) of 1280 bytes [RFC8200]. The network 386 therefore MUST forward packets of at least 1280 bytes without 387 generating an IPv6 Path MTU Discovery (PMTUD) Packet Too Big (PTB) 388 message [RFC8201]. 390 The OMNI interface configures an MTU of 9180 bytes [RFC2492]; the 391 size is therefore not a reflection of the underlying ANET interface 392 MTUs, but rather determines the largest packet the OMNI interface can 393 forward or reassemble. 395 The OMNI interface can employ link-layer IPv6 encapsulation and 396 fragmentation/reassembly per [RFC2473], but its use is OPTIONAL since 397 correct operation will result in either case. Implementations that 398 omit link-layer IPv6 fragmentation/reassembly may be more prone to 399 dropping large packets and returning a PTB, while those that include 400 it may see improved performance at the expense of including 401 additional code. In both cases, OMNI interface neighbors are 402 responsible for advertising their willingness to reassemble. 404 The OMNI interface returns internally-generated PTB messages for 405 packets admitted into the interface that it deems too large for the 406 outbound underlying ANET interface (e.g., according to ANET 407 performance characteristics, MTU, etc). For all other packets, the 408 OMNI interface performs PMTUD even if the destination appears to be 409 on the same link since a proxy on the path could return a PTB 410 message. This ensures that the path MTU is adaptive and reflects the 411 current path used for a given data flow. 413 The MN's OMNI interface forwards packets that are no larger than the 414 MTU of the selected underlying ANET interface according to the ANET 415 L2 frame format. When the OMNI interface forwards a packet that is 416 larger than the ANET interface MTU, it drops the packet and returns a 417 PTB if the AR is not willing to reassemble. 419 Otherwise, the OMNI interface encapsulates the packet in an IPv6 420 header with source address set to the MN's link-local address and 421 destination address set to the link-local address of the MSE (see: 422 Section 7). The OMNI interface then uses IPv6 fragmentation to break 423 the encapsulated packet into fragments that are no larger than the 424 ANET interface MTU and sends the fragments over the ANET where they 425 will be intercepted by the AR. The AR then reassembles and conveys 426 the packet toward the final destination. 428 When an AR receives a fragmented or whole packet from the INET 429 destined to an ANET MN, it first determines whether to forward or 430 drop and return a PTB. If the AR deems the packet to be of 431 acceptable size, it first reassembles locally (if necessary) then 432 forwards the packet to the MN. If the (reassembled) packet is no 433 larger than the ANET MTU, the AR forwards according to the ANET L2 434 frame format. If the packet is larger than the ANET MTU, the AR 435 instead uses link-layer IPv6 encapsulation and fragmentation as above 436 if the MN accepts fragments or drops and returns a PTB otherwise. 437 The MN then reassembles and discards the encapsulation header, then 438 forwards the whole packet to the final destination. 440 Applications that cannot tolerate loss due to MTU restrictions SHOULD 441 avoid sending packets larger than 1280 bytes, since dynamic path 442 changes can reduce the path MTU at any time. Applications that may 443 benefit from sending larger packets even though the path MTU may 444 change dynamically MAY use larger sizes (i.e., up to the OMNI 445 interface MTU). 447 Note that when the AR forwards a fragmented packet received from the 448 INET, it is imperative that the AR reassembles locally first instead 449 of blindly forwarding fragments directly to the MN to avoid attacks 450 such as tiny fragments, overlapping fragments, etc. 452 Note also that the OMNI interface can forward large packets via 453 encapsulation and fragmentation while at the same time returning 454 advisory PTB messages, e.g., subject to rate limiting. The receiving 455 node that performs reassembly can also send advisory PTB messages if 456 reassembly conditions become unfavorable. The OMNI interface can 457 therefore continuously forward large packets without loss while 458 returning advisory messages recommending a smaller size. 460 6. Frame Format 462 The OMNI interface transmits IPv6 packets according to the native 463 frame format of each underlying ANET interface. For example, for 464 Ethernet-compatible interfaces the frame format is specified in 465 [RFC2464], for aeronautical radio interfaces the frame format is 466 specified in standards such as ICAO Doc 9776 (VDL Mode 2 Technical 467 Manual), for tunnels over IPv6 the frame format is specified in 468 [RFC2473], etc. 470 7. Link-Local Addresses 472 OMNI interfaces assign IPv6 Link-Local Addresses (i.e., "OMNI LLAs") 473 using the following constructs: 475 o IPv6 MN OMNI LLAs encode the most-significant 64 bits of a MNP 476 within the least-significant 64 bits (i.e., the interface ID) of a 477 Link-Local IPv6 Unicast Address (see: [RFC4291], Section 2.5.6). 479 For example, for the MNP 2001:db8:1000:2000::/56 the corresponding 480 LLA is fe80::2001:db8:1000:2000. 482 o IPv4-compatible MN OMNI LLAs are assigned as fe80::ffff:[v4addr], 483 i.e., the most significant 10 bits of the prefix fe80::/10, 484 followed by 70 '0' bits, followed by 16 '1' bits, followed by a 485 32bit IPv4 address. For example, the IPv4-Compatible MN OMNI LLA 486 for 192.0.2.1 is fe80::ffff:192.0.2.1 (also written as 487 fe80::ffff:c000:0201). 489 o MSE OMNI LLAs are assigned from the range fe80::/96, and MUST be 490 managed for uniqueness. The lower 32 bits of the LLA includes a 491 unique integer value between '1' and 'feffffff', e.g., as in 492 fe80::1, fe80::2, fe80::3, etc., fe80::feff:ffff. The address 493 fe80:: is the link-local Subnet-Router anycast address [RFC4291] 494 and the address fe80::ffff:ffff is the "All-MSEs" address. The 495 address range fe80::ff00:0000/104 is reserved for future use. 496 (Note that distinct OMNI link segments can avoid overlap by 497 assigning MSE OMNI LLAs from unique fe80::/96 sub-prefixes. For 498 example, a first segment could assign from fe80::1000/116, a 499 second from fe80::2000/116, a third from fe80::3000/116, etc.) 501 Since the prefix 0000::/8 is "Reserved by the IETF" [RFC4291], no 502 MNPs can be allocated from that block ensuring that there is no 503 possibility for overlap between the above OMNI LLA constructs. 505 Since MN OMNI LLAs are based on the distribution of administratively 506 assured unique MNPs, and since MSE OMNI LLAs are guaranteed unique 507 through administrative assignment, OMNI interfaces set the 508 autoconfiguration variable DupAddrDetectTransmits to 0 [RFC4862]. 510 8. Address Mapping - Unicast 512 OMNI interfaces maintain a neighbor cache for tracking per-neighbor 513 state and use the link-local address format specified in Section 7. 514 IPv6 Neighbor Discovery (ND) [RFC4861] messages on MN OMNI interfaces 515 observe the native Source/Target Link-Layer Address Option (S/TLLAO) 516 formats of the underlying ANET interfaces (e.g., for Ethernet the S/ 517 TLLAO is specified in [RFC2464]). 519 MNs such as aircraft typically have many wireless data link types 520 (e.g. satellite-based, cellular, terrestrial, air-to-air directional, 521 etc.) with diverse performance, cost and availability properties. 522 The OMNI interface would therefore appear to have multiple L2 523 connections, and may include information for multiple ANET interfaces 524 in a single IPv6 ND message exchange. 526 OMNI interfaces use an IPv6 ND option called the "OMNI option" 527 formatted as shown in Figure 3: 529 0 1 2 3 530 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 531 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 532 | Type | Length | Prefix Length |A| Reserved | 533 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 534 | | 535 ~ Sub-Options ~ 536 | | 537 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 539 Figure 3: OMNI Option Format 541 In this format: 543 o Type is set to TBD. 545 o Length is set to the number of 8 octet blocks in the option. 547 o Prefix Length is set according to the IPv6 source address type. 548 For MN OMNI LLAs, the value is set to the length of the embedded 549 MNP. For IPv4-compatible MN OMNI LLAs, the value is set to 96 550 plus the length of the embedded IPv4 prefix. For MSE OMNI LLAs, 551 the value is set to 128. 553 o A (the "Accepts Fragments" bit) is set to '1' if the sender 554 accepts OMNI interface link-local fragments (see: Section 5); 555 otherwise, set to 0. 557 o Reserved is set to the value '0' on transmission and ignored on 558 reception. 560 o Sub-Options is a Variable-length field, of length such that the 561 complete OMNI Option is an integer multiple of 8 octets long. 562 Contains one or more options, as described in Section 8.1. 564 8.1. Sub-Options 566 The OMNI option includes zero or more Sub-Options, some of which may 567 appear multiple times in the same message. Each consecutive Sub- 568 Option is concatenated immediately after its predecessor. All Sub- 569 Options except Pad1 (see below) are type-length-value (TLV) encoded 570 in the following format: 572 0 1 2 573 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 574 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 575 | Sub-Type | Sub-length | Sub-Option Data ... 576 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 578 Figure 4: Sub-Option Format 580 o Sub-Type is a 1-byte field that encodes the Sub-Option type. Sub- 581 Options defined in this document are: 583 Option Name Sub-Type 584 Pad1 0 585 PadN 1 586 ifIndex-tuple (Type 1) 2 587 ifIndex-tuple (Type 2) 3 588 Register MSE ID 4 589 Release MSE ID 5 591 Figure 5 593 Sub-Types 253 and 254 are reserved for experimentation, as 594 recommended in[RFC3692]]. 596 o Sub-Length is a 1-byte field that encodes the length of the Sub- 597 Option Data, in bytes 599 o Sub-Option Data is a byte string with format determined by Sub- 600 Type 602 During processing, unrecognized Sub-Options are ignored and the next 603 Sub-Option processed until the end of the OMNI option. 605 The following Sub-Option types and formats are defined in this 606 document: 608 8.1.1. Pad1 610 0 611 0 1 2 3 4 5 6 7 612 +-+-+-+-+-+-+-+-+ 613 | Sub-Type=0 | 614 +-+-+-+-+-+-+-+-+ 616 Figure 6: Pad1 618 o Sub-Type is set to 0. 620 o No Sub-Length or Sub-Option Data follows (i.e., the "Sub-Option" 621 consists of a single zero octet). 623 8.1.2. PadN 625 0 1 2 626 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 627 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 628 | Sub-Type=1 |Sub-length=N-2 | N-2 padding bytes ... 629 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 631 Figure 7: PadN 633 o Sub-Type is set to 1. 635 o Sub-Length is set to N-2 being the number of padding bytes that 636 follow. 638 o Sub-Option Data consists of N-2 zero-valued octets. 640 8.1.3. ifIndex-tuple (Type 1) 642 0 1 2 3 643 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 644 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 645 | Sub-Type=2 | Sub-length=4+N| ifIndex | ifType | 646 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 647 | Provider ID | Link |S|I|RSV| Bitmap(0)=0xff|P00|P01|P02|P03| 648 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 649 |P04|P05|P06|P07|P08|P09|P10|P11|P12|P13|P14|P15|P16|P17|P18|P19| 650 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 651 |P20|P21|P22|P23|P24|P25|P26|P27|P28|P29|P30|P31| Bitmap(1)=0xff| 652 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 653 |P32|P33|P34|P35|P36|P37|P38|P39| ... 654 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 656 Figure 8: ifIndex-tuple (Type 1) 658 o Sub-Type is set to 2. 660 o Sub-Length is set to 4+N (the number of Sub-Option Data bytes that 661 follow). 663 o Sub-Option Data contains an "ifIndex-tuple" (Type 1) encoded as 664 follows (note that the first four bytes must be present): 666 * ifIndex is set to an 8-bit integer value corresponding to a 667 specific underlying ANET interface. OMNI options MAY include 668 multiple ifIndex-tuples, and MUST number each with an ifIndex 669 value between '1' and '255' that represents a MN-specific 8-bit 670 mapping for the actual ifIndex value assigned to the ANET 671 interface by network management [RFC2863] (the ifIndex value 672 '0' is reserved for use by the MS). Multiple ifIndex-tuples 673 with the same ifIndex value MAY appear in the same OMNI option. 675 * ifType is set to an 8-bit integer value corresponding to the 676 underlying ANET interface identified by ifIndex. The value 677 represents an OMNI interface-specific 8-bit mapping for the 678 actual IANA ifType value registered in the 'IANAifType-MIB' 679 registry [http://www.iana.org]. 681 * Provider ID is set to an OMNI interface-specific 8-bit ID value 682 for the network service provider associated with this ifIndex. 684 * Link encodes a 4-bit link metric. The value '0' means the link 685 is DOWN, and the remaining values mean the link is UP with 686 metric ranging from '1' ("lowest") to '15' ("highest"). 688 * S is set to '1' if this ifIndex-tuple corresponds to the 689 underlying ANET interface that is the source of the ND message. 690 Set to '0' otherwise. 692 * I is set to '0' ("Simplex") if the index for each singleton 693 Bitmap byte in the Sub-Option Data is inferred from its 694 sequential position (i.e., 0, 1, 2, ...), or set to '1' 695 ("Indexed") if each Bitmap is preceded by an Index byte. 696 Figure 8 shows the simplex case for I set to '0'. For I set to 697 '1', each Bitmap is instead preceded by an Index byte that 698 encodes a value "i" = (0 - 255) as the index for its companion 699 Bitmap as follows: 701 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 702 | Index=i | Bitmap(i) |P[*] values ... 703 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 705 Figure 9 707 * RSV is set to the value 0 on transmission and ignored on 708 reception. 710 * The remainder of the Sub-Option Data contains N = (0 - 251) 711 bytes of traffic classifier preferences consisting of a first 712 (indexed) Bitmap (i.e., "Bitmap(i)") followed by 0-8 1-byte 713 blocks of 2-bit P[*] values, followed by a second Bitmap (i), 714 followed by 0-8 blocks of P[*] values, etc. Reading from bit 0 715 to bit 7, the bits of each Bitmap(i) that are set to '1'' 716 indicate the P[*] blocks from the range P[(i*32)] through 717 P[(i*32) + 31] that follow; if any Bitmap(i) bits are '0', then 718 the corresponding P[*] block is instead omitted. For example, 719 if Bitmap(0) contains 0xff then the block with P[00]-P[03], 720 followed by the block with P[04]-P[07], etc., and ending with 721 the block with P[28]-P[31] are included (as showin in 722 Figure 8). The next Bitmap(i) is then consulted with its bits 723 indicating which P[*] blocks follow, etc. out to the end of the 724 Sub-Option. The first 16 P[*] blocks correspond to the 64 725 Differentiated Service Code Point (DSCP) values P[00] - P[63] 726 [RFC2474]. If additional P[*] blocks follow, their values 727 correspond to "pseudo-DSCP" traffic classifier values P[64], 728 P[65], P[66], etc. See Appendix A for further discussion and 729 examples. 731 * Each 2-bit P[*] field is set to the value '0' ("disabled"), '1' 732 ("low"), '2' ("medium") or '3' ("high") to indicate a QoS 733 preference level for ANET interface selection purposes. Not 734 all P[*] values need to be included in all OMNI option 735 instances of a given ifIndex-tuple. Any P[*] values 736 represented in an earlier OMNI option but ommitted in the 737 current OMNI option remain unchanged. Any P[*] values not yet 738 represented in any OMNI option default to "medium". 740 8.1.4. ifIndex-tuple (Type 2) 742 0 1 2 3 743 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 744 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 745 | Sub-Type=3 | Sub-length=4+N| ifIndex | ifType | 746 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 747 | Provider ID | Link |S|Resvd| ~ 748 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ 749 ~ ~ 750 ~ RFC 6088 Format Traffic Selector ~ 751 ~ ~ 752 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 754 Figure 10: ifIndex-tuple (Type 2) 756 o Sub-Type is set to 3. 758 o Sub-Length is set to 4+N (the number of Sub-Option Data bytes that 759 follow). 761 o Sub-Option Data contains an "ifIndex-tuple" (Type 2) encoded as 762 follows (note that the first four bytes must be present): 764 * ifIndex, ifType, Provider ID, Link and S are set exactly as for 765 Type 1 ifIndex-tuples as specified in Section 8.1.3. 767 * the remainder of the Sub-Option body encodes a variable-length 768 traffic selector formatted per [RFC6088], beginning with the 769 "TS Format" field. 771 8.1.5. Register MSE ID 773 0 1 2 3 774 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 775 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 776 | Sub-Type=4 | Sub-length=4 | MSE ID (bits 0 - 15) | 777 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 778 | MSE ID (bits 16 - 32) | 779 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 781 Figure 11: Register MSE ID 783 o Sub-Type is set to 4. 785 o Sub-Length is set to 4. 787 o Register MSE ID contains the least-significant 32 bits of an MSE 788 OMNI LLA for MNP registration, e.g., for the LLA fe80::face:cafe 789 the field contains the value 0xfacecafe. The value 0x0 signifies 790 "any" MSE selected by the AR, and the value 0xffffffff signifies 791 "all" MSEs. OMNI options contain zero or more Register MSE IDs. 793 8.1.6. Release MSE ID 795 0 1 2 3 796 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 797 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 798 | Sub-Type=5 | Sub-length=4 | MSE ID (bits 0 - 15) | 799 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 800 | MSE ID (bits 16 - 32) | 801 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 803 Figure 12: Release MSE ID 805 o Sub-Type is set to 5. 807 o Sub-Length is set to 4. 809 o Release MSE ID contains the least-significant 32 bits of an MSE 810 OMNI LLA for MNP withdrawal. OMNI options contain zero or more 811 Release MSE IDs. 813 9. Address Mapping - Multicast 815 The multicast address mapping of the native underlying ANET interface 816 applies. The mobile router on board the aircraft also serves as an 817 IGMP/MLD Proxy for its EUNs and/or hosted applications per [RFC4605] 818 while using the L2 address of the router as the L2 address for all 819 multicast packets. 821 10. Conceptual Sending Algorithm 823 The MN's IPv6 layer selects the outbound OMNI interface according to 824 standard IPv6 requirements when forwarding data packets from local or 825 EUN applications to external correspondents. The OMNI interface 826 maintains default routes and neighbor cache entries for MSEs, and may 827 also include additional neighbor cache entries created through other 828 means (e.g., Address Resolution, static configuration, etc.). 830 After a packet enters the OMNI interface, an outbound ANET interface 831 is selected based on multilink parameters such as DSCP, application 832 port number, cost, performance, message size, etc. OMNI interface 833 multilink selections could also be configured to perform replication 834 across multiple ANET interfaces for increased reliability at the 835 expense of packet duplication. 837 OMNI interface multilink service designers MUST observe the BCP 838 guidance in Section 15 [RFC3819] in terms of implications for 839 reordering when packets from the same flow may be spread across 840 multiple ANET interfaces having diverse properties. 842 10.1. Multiple OMNI Interfaces 844 MNs may associate with multiple MS instances concurrently. Each MS 845 instance represents a distinct OMNI link distinguished by its 846 associated MSPs. The MN configures a separate OMNI interface for 847 each link so that multiple interfaces (e.g., omni0, omni1, omni2, 848 etc.) are exposed to the IPv6 layer. 850 Depending on local policy and configuration, an MN may choose between 851 alternative active OMNI interfaces using a packet's DSCP, routing 852 information or static configuration. Interface selection based on 853 per-packet source addresses is also enabled when the MSPs for each 854 OMNI interface are known (e.g., discovered through Prefix Information 855 Options (PIOs) and/or Route Information Options (RIOs)). 857 Each OMNI interface can be configured over the same or different sets 858 of ANET interfaces. Each ANET distinguishes between the different 859 OMNI links based on the MSPs represented in per-packet IPv6 860 addresses. 862 Multiple distinct OMNI links can therefore be used to support fault 863 tolerance, load balancing, reliability, etc. The architectural model 864 parallels Layer 2 Virtual Local Area Networks (VLANs), where the MSPs 865 serve as (virtual) VLAN tags. 867 11. Router Discovery and Prefix Registration 869 MNs interface with the MS by sending RS messages with OMNI options. 870 For each ANET interface, the MN sends an RS message with an OMNI 871 option with Register/Release MSE ID suboptions, and with destination 872 address set to All-Routers multicast (ff02::2) [RFC4291]. The MN 873 discovers MSE OMNI LLAs either through an RA message response to an 874 initial anycast/multicast RS or before sending an initial RS message. 875 [RFC5214] provides example MSE address discovery methods, including 876 information conveyed during data link login, name service lookups, 877 static configuration, etc. 879 MNs configure OMNI interfaces that observe the properties discussed 880 in the previous section. The OMNI interface and its underlying 881 interfaces are said to be in either the "UP" or "DOWN" state 882 according to administrative actions in conjunction with the interface 883 connectivity status. An OMNI interface transitions to UP or DOWN 884 through administrative action and/or through state transitions of the 885 underlying interfaces. When a first underlying interface transitions 886 to UP, the OMNI interface also transitions to UP. When all 887 underlying interfaces transition to DOWN, the OMNI interface also 888 transitions to DOWN. 890 When an OMNI interface transitions to UP, the MN sends RS messages to 891 register its MNP and an initial set of underlying ANET interfaces 892 that are also UP. The MN sends additional RS messages to refresh 893 lifetimes and to register/deregister underlying ANET interfaces as 894 they transition to UP or DOWN. The MN sends initial RS messages over 895 an UP underlying interface with its OMNI LLA as the source and with 896 destination set to All-Routers multicast. The RS messages include an 897 OMNI option per Section 8 with a valid Prefix Length, flags, with 898 ifIndex-tuples appropriate for underlying ANET interfaces and with 899 Register/Release MSE ID options. 901 ARs process IPv6 ND messages with OMNI options and act as a proxy for 902 MSEs. ARs receive RS messages and coordinate with MSEs in a manner 903 outside the scope of this document. The AR returns an RA message 904 with source address set to Subnet-Router anycast (fe80::), with an 905 OMNI option with Register/Release MSE IDs, and with any information 906 for the link that would normally be delivered in a solicited RA 907 message. ARs return RA messages with configuration information in 908 response to a MN's RS messages. The AR sets the RA Cur Hop Limit, M 909 and O flags, Router Lifetime, Reachable Time and Retrans Timer 910 values, and includes any necessary options such as: 912 o PIOs with (A; L=0) that include MSPs for the link [RFC8028]. 914 o RIOs [RFC4191] with more-specific routes. 916 o an MTU option that specifies the maximum acceptable packet size 917 for this ANET interface. 919 The AR coordinates with each MSE and sends immediate unicast RA 920 responses without delay; therefore, the IPv6 ND MAX_RA_DELAY_TIME and 921 MIN_DELAY_BETWEEN_RAS constants for multicast RAs do not apply. The 922 AR MAY send periodic and/or event-driven unsolicited RA messages, but 923 is not required to do so for unicast advertisements [RFC4861]. 925 When the MSE processes the OMNI information, it first validates the 926 prefix registration information. If the prefix registration was 927 valid, the MSE injects the MNP into the routing/mapping system then 928 caches the new Prefix Length, MNP and ifIndex-tuples. The MSE then 929 informs the AR of registration success/failure, and the AR adds the 930 MSE to the list of Register/Release IDs to return an RA message OMNI 931 option per Section 8. 933 When the MN receives the RA message, it creates a default route and 934 neighbor cache entry for each Register MSE ID with the AR's address 935 as the L2 address. If the MN connects to multiple ANETs, it 936 establishes mutliple AR L2 addresses for each MSE (i.e., as a 937 Multilink neighbor). The MN then manages its underlying ANET 938 interfaces according to their states as follows: 940 o When an underlying ANET interface transitions to UP, the MN sends 941 an RS over the ANET interface with an OMNI option. The OMNI 942 option contains at least one ifIndex-tuple with values specific to 943 this ANET interface, and may contain additional ifIndex-tuples 944 specific to this and/or other ANET interfaces. 946 o When an underlying ANET interface transitions to DOWN, the MN 947 sends an RS or unsolicited NA message over any UP ANET interface 948 with an OMNI option containing an ifIndex-tuple for the DOWN ANET 949 interface with Link set to '0'. The MN sends an RS when an 950 acknowledgement is required, or an unsolicited NA when reliability 951 is not thought to be a concern (e.g., if redundant transmissions 952 are sent on multiple ANET interfaces). 954 o When the Router Lifetime for a specific ANET interface nears 955 expiration, the MN sends an RS over the ANET interface to receive 956 a fresh RA. If no RA is received, the MN marks the ANET interface 957 as DOWN. 959 o When a MN wishes to release from one or more current MSEs, it 960 sends an RS or unsolicited NA message over any UP ANET interfaces 961 with an OMNI option with a Release ID for each MSE. Each MSE then 962 withdraws the MNP from the routing/mapping system and (for RS 963 responses) directs the AR to return an RA message with an OMNI 964 option with Release MSE IDs. 966 o When all of a MNs underlying interfaces have transitioned to DOWN 967 (or if the prefix registration lifetime expires) the MSE withdraws 968 the MNP the same as if it had received a message with an OMNI 969 option with a Release MSE ID. 971 The MN is responsible for retrying each RS exchange up to 972 MAX_RTR_SOLICITATIONS times separated by RTR_SOLICITATION_INTERVAL 973 seconds until an RA is received. If no RA is received over a single 974 UP ANET interface, the MN declares this ANET interface as DOWN. If 975 no RA is received over multiple UP ANET interfaces, the MN declares 976 this MSE unreachable and tries a different MSE. 978 The IPv6 layer sees the OMNI interface as an ordinary IPv6 interface. 979 Therefore, when the IPv6 layer sends an RS message the OMNI interface 980 returns an internally-generated RA message as though the message 981 originated from an IPv6 router. The internally-generated RA message 982 contains configuration information that is consistent with the 983 information received from the RAs generated by the MS. Whether the 984 OMNI interface IPv6 ND messaging process is initiated from the 985 receipt of an RS message from the IPv6 layer is an implementation 986 matter. Some implementations may elect to defer the IPv6 ND 987 messaging process until an RS is received from the IPv6 layer, while 988 others may elect to initiate the process proactively. 990 Note: The Router Lifetime value in RA messages indicates the time 991 before which the MN must send another RS message over this ANET 992 interface (e.g., 600 seconds), however that timescale may be 993 significantly longer than the lifetime the MS has committed to retain 994 the prefix registration (e.g., REACHABLETIME seconds). ARs are 995 therefore responsible for keeping MS state alive on a finer-grained 996 timescale than the MN is required to do on its own behalf. 998 12. AR and MSE Resilience 1000 ANETs SHOULD deploy ARs in Virtual Router Redundancy Protocol (VRRP) 1001 [RFC5798] configurations so that service continuity is maintained 1002 even if one or more ARs fail. Using VRRP, the MN is unaware which of 1003 the (redundant) ARs is currently providing service, and any service 1004 discontinuity will be limited to the failover time supported by VRRP. 1005 Widely deployed public domain implementations of VRRP are available. 1007 MSEs SHOULD use high availability clustering services so that 1008 multiple redundant systems can provide coordinated response to 1009 failures. As with VRRP, widely deployed public domain 1010 implementations of high availability clustering services are 1011 available. Note that special-purpose and expensive dedicated 1012 hardware is not necessary, and public domain implementations can be 1013 used even between lightweight virtual machines in cloud deployments. 1015 13. Detecting and Responding to MSE Failures 1017 In environments where fast recovery from MSE failure is required, ARs 1018 SHOULD use proactive Neighbor Unreachability Detection (NUD) in a 1019 manner that parallels Bidirectional Forwarding Detection (BFD) 1020 [RFC5880] to track MSE reachability. ARs can then quickly detect and 1021 react to failures so that cached information is re-established 1022 through alternate paths. Proactive NUD control messaging is carried 1023 only over well-connected ground domain networks (i.e., and not low- 1024 end ANET links such as aeronautical radios) and can therefore be 1025 tuned for rapid response. 1027 ARs perform proactive NUD for MSEs for which there are currently 1028 active ANET MNs. If an MSE fails, ARs can quickly inform MNs of the 1029 outage by sending multicast RA messages on the ANET interface. The 1030 AR sends RA messages to the MN via the ANET interface with an OMNI 1031 option with a Release ID for the failed MSE, and with destination 1032 address set to All-Nodes multicast (ff02::1) [RFC4291]. 1034 The AR SHOULD send MAX_FINAL_RTR_ADVERTISEMENTS RA messages separated 1035 by small delays [RFC4861]. Any MNs on the ANET interface that have 1036 been using the (now defunct) MSE will receive the RA messages and 1037 associate with a new MSE. 1039 14. Transition Considerations 1041 When a MN connects to an ANET for the first time, it sends an RS 1042 message with an OMNI option as discussed above. If the first hop AR 1043 recognizes the option, it returns an RA with an OMNI option and with 1044 a Subnet-Router anycast source LLA (fe80::). The MN then engages the 1045 ANET according to OMNI link model specified in this document. 1047 If the first hop AR is a legacy IPv6 router, however, it instead 1048 returns an RA message with no OMNI option and with a unicast source 1049 LLA as specified in [RFC4861]. In that case, the MN engages the ANET 1050 according to the legacy IPv6 link model and without the OMNI 1051 extensions specified in this document. 1053 15. IANA Considerations 1055 The IANA is instructed to allocate an official Type number TBD from 1056 the registry "IPv6 Neighbor Discovery Option Formats" for the OMNI 1057 option. Implementations set Type to 253 as an interim value 1058 [RFC4727]. 1060 The OMNI option also defines an 8-bit Sub-Type field, for which IANA 1061 is instructed to create and maintain a new registry entitled "OMNI 1062 option Sub-Type values". Initial values for the OMNI option Sub-Type 1063 values registry are given below; future assignments are to be made 1064 through Expert Review [RFC8126]. 1066 Value Sub-Type name Reference 1067 ----- ------------- ---------- 1068 0 Pad1 [RFCXXXX] 1069 1 PadN [RFCXXXX] 1070 2 ifIndex-tuple (Type 1) [RFCXXXX] 1071 3 ifIndex-tuple (Type 2) [RFCXXXX] 1072 4 Register MSE ID [RFCXXXX] 1073 5 Release MSE ID [RFCXXXX] 1074 6-252 Unassigned 1075 253-254 Experimental [RFCXXXX] 1076 255 Reserved [RFCXXXX] 1078 Figure 13: OMNI Option Sub-Type Values 1080 16. Security Considerations 1082 Security considerations for IPv6 [RFC8200] and IPv6 Neighbor 1083 Discovery [RFC4861] apply. OMNI interface IPv6 ND messages SHOULD 1084 include Nonce and Timestamp options [RFC3971] when synchronized 1085 transaction confirmation is needed. 1087 Security considerations for specific access network interface types 1088 are covered under the corresponding IP-over-(foo) specification 1089 (e.g., [RFC2464], [RFC2492], etc.). 1091 17. Acknowledgements 1093 The first version of this document was prepared per the consensus 1094 decision at the 7th Conference of the International Civil Aviation 1095 Organization (ICAO) Working Group-I Mobility Subgroup on March 22, 1096 2019. Consensus to take the document forward to the IETF was reached 1097 at the 9th Conference of the Mobility Subgroup on November 22, 2019. 1098 Attendees and contributors included: Guray Acar, Danny Bharj, 1099 Francois D'Humieres, Pavel Drasil, Nikos Fistas, Giovanni Garofolo, 1100 Bernhard Haindl, Vaughn Maiolla, Tom McParland, Victor Moreno, Madhu 1101 Niraula, Brent Phillips, Liviu Popescu, Jacky Pouzet, Aloke Roy, Greg 1102 Saccone, Robert Segers, Michal Skorepa, Michel Solery, Stephane 1103 Tamalet, Fred Templin, Jean-Marc Vacher, Bela Varkonyi, Tony Whyman, 1104 Fryderyk Wrobel and Dongsong Zeng. 1106 The following individuals are acknowledged for their useful comments: 1107 Michael Matyas, Madhu Niraula, Greg Saccone, Stephane Tamalet, Eric 1108 Vyncke. Pavel Drasil, Zdenek Jaron and Michal Skorepa are recognized 1109 for their many helpful ideas and suggestions. 1111 This work is aligned with the NASA Safe Autonomous Systems Operation 1112 (SASO) program under NASA contract number NNA16BD84C. 1114 This work is aligned with the FAA as per the SE2025 contract number 1115 DTFAWA-15-D-00030. 1117 18. References 1119 18.1. Normative References 1121 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1122 Requirement Levels", BCP 14, RFC 2119, 1123 DOI 10.17487/RFC2119, March 1997, 1124 . 1126 [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, 1127 "Definition of the Differentiated Services Field (DS 1128 Field) in the IPv4 and IPv6 Headers", RFC 2474, 1129 DOI 10.17487/RFC2474, December 1998, 1130 . 1132 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 1133 "SEcure Neighbor Discovery (SEND)", RFC 3971, 1134 DOI 10.17487/RFC3971, March 2005, 1135 . 1137 [RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and 1138 More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191, 1139 November 2005, . 1141 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 1142 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 1143 2006, . 1145 [RFC4727] Fenner, B., "Experimental Values In IPv4, IPv6, ICMPv4, 1146 ICMPv6, UDP, and TCP Headers", RFC 4727, 1147 DOI 10.17487/RFC4727, November 2006, 1148 . 1150 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 1151 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 1152 DOI 10.17487/RFC4861, September 2007, 1153 . 1155 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 1156 Address Autoconfiguration", RFC 4862, 1157 DOI 10.17487/RFC4862, September 2007, 1158 . 1160 [RFC6088] Tsirtsis, G., Giarreta, G., Soliman, H., and N. Montavont, 1161 "Traffic Selectors for Flow Bindings", RFC 6088, 1162 DOI 10.17487/RFC6088, January 2011, 1163 . 1165 [RFC8028] Baker, F. and B. Carpenter, "First-Hop Router Selection by 1166 Hosts in a Multi-Prefix Network", RFC 8028, 1167 DOI 10.17487/RFC8028, November 2016, 1168 . 1170 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1171 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1172 May 2017, . 1174 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1175 (IPv6) Specification", STD 86, RFC 8200, 1176 DOI 10.17487/RFC8200, July 2017, 1177 . 1179 [RFC8201] McCann, J., Deering, S., Mogul, J., and R. Hinden, Ed., 1180 "Path MTU Discovery for IP version 6", STD 87, RFC 8201, 1181 DOI 10.17487/RFC8201, July 2017, 1182 . 1184 18.2. Informative References 1186 [RFC2225] Laubach, M. and J. Halpern, "Classical IP and ARP over 1187 ATM", RFC 2225, DOI 10.17487/RFC2225, April 1998, 1188 . 1190 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 1191 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 1192 . 1194 [RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in 1195 IPv6 Specification", RFC 2473, DOI 10.17487/RFC2473, 1196 December 1998, . 1198 [RFC2492] Armitage, G., Schulter, P., and M. Jork, "IPv6 over ATM 1199 Networks", RFC 2492, DOI 10.17487/RFC2492, January 1999, 1200 . 1202 [RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group 1203 MIB", RFC 2863, DOI 10.17487/RFC2863, June 2000, 1204 . 1206 [RFC3692] Narten, T., "Assigning Experimental and Testing Numbers 1207 Considered Useful", BCP 82, RFC 3692, 1208 DOI 10.17487/RFC3692, January 2004, 1209 . 1211 [RFC3819] Karn, P., Ed., Bormann, C., Fairhurst, G., Grossman, D., 1212 Ludwig, R., Mahdavi, J., Montenegro, G., Touch, J., and L. 1213 Wood, "Advice for Internet Subnetwork Designers", BCP 89, 1214 RFC 3819, DOI 10.17487/RFC3819, July 2004, 1215 . 1217 [RFC4605] Fenner, B., He, H., Haberman, B., and H. Sandick, 1218 "Internet Group Management Protocol (IGMP) / Multicast 1219 Listener Discovery (MLD)-Based Multicast Forwarding 1220 ("IGMP/MLD Proxying")", RFC 4605, DOI 10.17487/RFC4605, 1221 August 2006, . 1223 [RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V., 1224 Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", 1225 RFC 5213, DOI 10.17487/RFC5213, August 2008, 1226 . 1228 [RFC5214] Templin, F., Gleeson, T., and D. Thaler, "Intra-Site 1229 Automatic Tunnel Addressing Protocol (ISATAP)", RFC 5214, 1230 DOI 10.17487/RFC5214, March 2008, 1231 . 1233 [RFC5798] Nadas, S., Ed., "Virtual Router Redundancy Protocol (VRRP) 1234 Version 3 for IPv4 and IPv6", RFC 5798, 1235 DOI 10.17487/RFC5798, March 2010, 1236 . 1238 [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection 1239 (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, 1240 . 1242 [RFC6543] Gundavelli, S., "Reserved IPv6 Interface Identifier for 1243 Proxy Mobile IPv6", RFC 6543, DOI 10.17487/RFC6543, May 1244 2012, . 1246 [RFC7084] Singh, H., Beebee, W., Donley, C., and B. Stark, "Basic 1247 Requirements for IPv6 Customer Edge Routers", RFC 7084, 1248 DOI 10.17487/RFC7084, November 2013, 1249 . 1251 [RFC7421] Carpenter, B., Ed., Chown, T., Gont, F., Jiang, S., 1252 Petrescu, A., and A. Yourtchenko, "Analysis of the 64-bit 1253 Boundary in IPv6 Addressing", RFC 7421, 1254 DOI 10.17487/RFC7421, January 2015, 1255 . 1257 [RFC7847] Melia, T., Ed. and S. Gundavelli, Ed., "Logical-Interface 1258 Support for IP Hosts with Multi-Access Support", RFC 7847, 1259 DOI 10.17487/RFC7847, May 2016, 1260 . 1262 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 1263 Writing an IANA Considerations Section in RFCs", BCP 26, 1264 RFC 8126, DOI 10.17487/RFC8126, June 2017, 1265 . 1267 Appendix A. Type 1 ifIndex-tuple Traffic Classifier Preference Encoding 1269 Adaptation of the OMNI option Type 1 ifIndex-tuple's traffic 1270 classifier Bitmap to specific Internetworks such as the Aeronautical 1271 Telecommunications Network with Internet Protocol Services (ATN/IPS) 1272 may include link selection preferences based on other traffic 1273 classifiers (e.g., transport port numbers, etc.) in addition to the 1274 existing DSCP-based preferences. Nodes on specific Internetworks 1275 maintain a map of traffic classifiers to additional P[*] preference 1276 fields beyond the first 64. For example, TCP port 22 maps to P[67], 1277 TCP port 443 maps to P[70], UDP port 8060 maps to P[76], etc. 1279 Implementations use Simplex or Indexed encoding formats for P[*] 1280 encoding in order to encode a given set of traffic classifiers in the 1281 most efficient way. Some use cases may be more efficiently coded 1282 using Simplex form, while others may be more efficient using Indexed. 1283 Once a format is selected for preparation of a single ifIndex-tuple 1284 the same format must be used for the entire Sub-Option. Different 1285 Sub-Options may use different formats. 1287 The following figures show coding examples for various Simplex and 1288 Indexed formats: 1290 0 1 2 3 1291 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1292 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1293 | Sub-Type=2 | Sub-length=4+N| ifIndex | ifType | 1294 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1295 | Provider ID | Link |S|0|RSV| Bitmap(0)=0xff|P00|P01|P02|P03| 1296 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1297 |P04|P05|P06|P07|P08|P09|P10|P11|P12|P13|P14|P15|P16|P17|P18|P19| 1298 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1299 |P20|P21|P22|P23|P24|P25|P26|P27|P28|P29|P30|P31| Bitmap(1)=0xff| 1300 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1301 |P32|P33|P34|P35|P36|P37|P38|P39|P40|P41|P42|P43|P44|P45|P46|P47| 1302 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1303 |P48|P49|P50|P51|P52|P53|P54|P55|P56|P57|P58|P59|P60|P61|P62|P63| 1304 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1305 | Bitmap(2)=0xff|P64|P65|P67|P68| ... 1306 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 1308 Figure 14: Example 1: Dense Simplex Encoding 1310 0 1 2 3 1311 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1312 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1313 | Sub-Type=2 | Sub-length=4+N| ifIndex | ifType | 1314 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1315 | Provider ID | Link |S|0|RSV| Bitmap(0)=0x00| Bitmap(1)=0x0f| 1316 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1317 |P48|P49|P50|P51|P52|P53|P54|P55|P56|P57|P58|P59|P60|P61|P62|P63| 1318 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1319 | Bitmap(2)=0x00| Bitmap(3)=0x00| Bitmap(4)=0x00| Bitmap(5)=0x00| 1320 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1321 | Bitmap(6)=0xf0|192|193|194|195|196|197|198|199|200|201|202|203| 1322 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1323 |204|205|206|207| Bitmap(7)=0x00| Bitmap(8)=0x0f|272|273|274|275| 1324 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1325 |276|277|278|279|280|281|282|283|284|285|286|287| Bitmap(9)=0x00| 1326 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1327 |Bitmap(10)=0x00| ... 1328 +-+-+-+-+-+-+-+-+-+-+- 1330 Figure 15: Example 2: Sparse Simplex Encoding 1332 0 1 2 3 1333 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 1334 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1335 | Sub-Type=2 | Sub-length=4+N| ifIndex | ifType | 1336 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1337 | Provider ID | Link |S|1|RSV| Index = 0x00 | Bitmap = 0x80 | 1338 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1339 |P00|P01|P02|P03| Index = 0x01 | Bitmap = 0x01 |P60|P61|P62|P63| 1340 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1341 | Index = 0x10 | Bitmap = 0x80 |512|513|514|515| Index = 0x18 | 1342 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1343 | Bitmap = 0x01 |796|797|798|799| ... 1344 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 1346 Figure 16: Example 3: Indexed Encoding 1348 Appendix B. Prefix Length Considerations 1350 The 64-bit boundary in IPv6 addresses [RFC7421] determines the MN 1351 OMNI LLA format for encoding the most-significant 64 MNP bits into 1352 the least-significant 64 bits of the prefix fe80::/64 as discussed in 1353 Section 7. 1355 [RFC4291] defines the link-local address format as the most 1356 significant 10 bits of the prefix fe80::/10, followed by 54 unused 1357 bits, followed by the least-significant 64 bits of the address. If 1358 the 64-bit boundary is relaxed through future standards activity, 1359 then the 54 unused bits can be employed for extended coding of MNPs 1360 of length /65 up to /118. 1362 The extended coding format would continue to encode MNP bits 0-63 in 1363 bits 64-127 of the OMNI LLA, while including MNP bits 64-117 in bits 1364 10-63. For example, the OMNI LLA corresponding to the MNP 1365 2001:db8:1111:2222:3333:4444:5555::/112 would be 1366 fe8c:ccd1:1115:5540:2001:db8:1111:2222/128, and would still be a 1367 valid IPv6 LLA per [RFC4291]. However, a prefix length shorter than 1368 /128 cannot be applied due to the non-sequential byte ordering. 1370 Note that if the 64-bit boundary were relaxed an alternate form of 1371 OMNI LLA construction could be employed by embedding the MNP 1372 beginning with the most significant bit immediately following bit 10 1373 of the prefix fe80::/10. For example, the OMNI LLA corresponding to 1374 the MNP 2001:db8:1111:2222:3333:4444:5555::/112 would be written as 1375 fe88:0043:6e04:4448:888c:ccd1:1115:5540/122. This alternate form may 1376 provide a more natural coding for the MS along with the ability to 1377 apply a fully-qualified prefix length. It has the disadvantages of 1378 requiring an unweildy 10-bit right-shift of a 16byte address, as well 1379 as presenting a non-human-readable form. 1381 Appendix C. VDL Mode 2 Considerations 1383 ICAO Doc 9776 is the "Technical Manual for VHF Data Link Mode 2" 1384 (VDLM2) that specifies an essential radio frequency data link service 1385 for aircraft and ground stations in worldwide civil aviation air 1386 traffic management. The VDLM2 link type is "multicast capable" 1387 [RFC4861], but with considerable differences from common multicast 1388 links such as Ethernet and IEEE 802.11. 1390 First, the VDLM2 link data rate is only 31.5Kbps - multiple orders of 1391 magnitude less than most modern wireless networking gear. Second, 1392 due to the low available link bandwidth only VDLM2 ground stations 1393 (i.e., and not aircraft) are permitted to send broadcasts, and even 1394 so only as compact layer 2 "beacons". Third, aircraft employ the 1395 services of ground stations by performing unicast RS/RA exchanges 1396 upon receipt of beacons instead of listening for multicast RA 1397 messages and/or sending multicast RS messages. 1399 This beacon-oriented unicast RS/RA approach is necessary to conserve 1400 the already-scarce available link bandwidth. Moreover, since the 1401 numbers of beaconing ground stations operating within a given spatial 1402 range must be kept as sparse as possible, it would not be feasible to 1403 have different classes of ground stations within the same region 1404 observing different protocols. It is therefore highly desirable that 1405 all ground stations observe a common language of RS/RA as specified 1406 in this document. 1408 Note that links of this nature may benefit from compression 1409 techniques that reduce the bandwidth necessary for conveying the same 1410 amount of data. The IETF lpwan working group is considering possible 1411 alternatives: [https://datatracker.ietf.org/wg/lpwan/documents]. 1413 Appendix D. Change Log 1415 << RFC Editor - remove prior to publication >> 1417 Differences from draft-templin-6man-omni-interface-04 to draft- 1418 templin-6man-omni-interface-05: 1420 o Transition considerations, and overhaul of RS/RA addressing with 1421 the inclusion of MSE addresses within the OMNI option instead of 1422 as RS/RA addresses (developed under FAA SE2025 contract number 1423 DTFAWA-15-D-00030). 1425 Differences from draft-templin-6man-omni-interface-02 to draft- 1426 templin-6man-omni-interface-03: 1428 o Added "advisory PTB messages" under FAA SE2025 contract number 1429 DTFAWA-15-D-00030. 1431 Differences from draft-templin-6man-omni-interface-01 to draft- 1432 templin-6man-omni-interface-02: 1434 o Removed "Primary" flag and supporting text. 1436 o Clarified that "Router Lifetime" applies to each ANET interface 1437 independently, and that the union of all ANET interface Router 1438 Lifetimes determines MSE lifetime. 1440 Differences from draft-templin-6man-omni-interface-00 to draft- 1441 templin-6man-omni-interface-01: 1443 o "All-MSEs" OMNI LLA defined. Also reserverd fe80::ff00:0000/104 1444 for future use (most likely as "pseudo-multicast"). 1446 o Non-normative discussion of alternate OMNI LLA construction form 1447 made possible if the 64-bit assumption were relaxed. 1449 Differences from draft-templin-atn-aero-interface-21 to draft- 1450 templin-6man-omni-interface-00: 1452 o Minor clarification on Type-2 ifIndex-tuple encoding. 1454 o Draft filename change (replaces draft-templin-atn-aero-interface). 1456 Differences from draft-templin-atn-aero-interface-20 to draft- 1457 templin-atn-aero-interface-21: 1459 o OMNI option format 1461 o MTU 1463 Differences from draft-templin-atn-aero-interface-19 to draft- 1464 templin-atn-aero-interface-20: 1466 o MTU 1468 Differences from draft-templin-atn-aero-interface-18 to draft- 1469 templin-atn-aero-interface-19: 1471 o MTU 1473 Differences from draft-templin-atn-aero-interface-17 to draft- 1474 templin-atn-aero-interface-18: 1476 o MTU and RA configuration information updated. 1478 Differences from draft-templin-atn-aero-interface-16 to draft- 1479 templin-atn-aero-interface-17: 1481 o New "Primary" flag in OMNI option. 1483 Differences from draft-templin-atn-aero-interface-15 to draft- 1484 templin-atn-aero-interface-16: 1486 o New note on MSE OMNI LLA uniqueness assurance. 1488 o General cleanup. 1490 Differences from draft-templin-atn-aero-interface-14 to draft- 1491 templin-atn-aero-interface-15: 1493 o General cleanup. 1495 Differences from draft-templin-atn-aero-interface-13 to draft- 1496 templin-atn-aero-interface-14: 1498 o General cleanup. 1500 Differences from draft-templin-atn-aero-interface-12 to draft- 1501 templin-atn-aero-interface-13: 1503 o Minor re-work on "Notify-MSE" (changed to Notification ID). 1505 Differences from draft-templin-atn-aero-interface-11 to draft- 1506 templin-atn-aero-interface-12: 1508 o Removed "Request/Response" OMNI option formats. Now, there is 1509 only one OMNI option format that applies to all ND messages. 1511 o Added new OMNI option field and supporting text for "Notify-MSE". 1513 Differences from draft-templin-atn-aero-interface-10 to draft- 1514 templin-atn-aero-interface-11: 1516 o Changed name from "aero" to "OMNI" 1518 o Resolved AD review comments from Eric Vyncke (posted to atn list) 1520 Differences from draft-templin-atn-aero-interface-09 to draft- 1521 templin-atn-aero-interface-10: 1523 o Renamed ARO option to AERO option 1524 o Re-worked Section 13 text to discuss proactive NUD. 1526 Differences from draft-templin-atn-aero-interface-08 to draft- 1527 templin-atn-aero-interface-09: 1529 o Version and reference update 1531 Differences from draft-templin-atn-aero-interface-07 to draft- 1532 templin-atn-aero-interface-08: 1534 o Removed "Classic" and "MS-enabled" link model discussion 1536 o Added new figure for MN/AR/MSE model. 1538 o New Section on "Detecting and responding to MSE failure". 1540 Differences from draft-templin-atn-aero-interface-06 to draft- 1541 templin-atn-aero-interface-07: 1543 o Removed "nonce" field from AR option format. Applications that 1544 require a nonce can include a standard nonce option if they want 1545 to. 1547 o Various editorial cleanups. 1549 Differences from draft-templin-atn-aero-interface-05 to draft- 1550 templin-atn-aero-interface-06: 1552 o New Appendix C on "VDL Mode 2 Considerations" 1554 o New Appendix D on "RS/RA Messaging as a Single Standard API" 1556 o Various significant updates in Section 5, 10 and 12. 1558 Differences from draft-templin-atn-aero-interface-04 to draft- 1559 templin-atn-aero-interface-05: 1561 o Introduced RFC6543 precedent for focusing IPv6 ND messaging to a 1562 reserved unicast link-layer address 1564 o Introduced new IPv6 ND option for Aero Registration 1566 o Specification of MN-to-MSE message exchanges via the ANET access 1567 router as a proxy 1569 o IANA Considerations updated to include registration requests and 1570 set interim RFC4727 option type value. 1572 Differences from draft-templin-atn-aero-interface-03 to draft- 1573 templin-atn-aero-interface-04: 1575 o Removed MNP from aero option format - we already have RIOs and 1576 PIOs, and so do not need another option type to include a Prefix. 1578 o Clarified that the RA message response must include an aero option 1579 to indicate to the MN that the ANET provides a MS. 1581 o MTU interactions with link adaptation clarified. 1583 Differences from draft-templin-atn-aero-interface-02 to draft- 1584 templin-atn-aero-interface-03: 1586 o Sections re-arranged to match RFC4861 structure. 1588 o Multiple aero interfaces 1590 o Conceptual sending algorithm 1592 Differences from draft-templin-atn-aero-interface-01 to draft- 1593 templin-atn-aero-interface-02: 1595 o Removed discussion of encapsulation (out of scope) 1597 o Simplified MTU section 1599 o Changed to use a new IPv6 ND option (the "aero option") instead of 1600 S/TLLAO 1602 o Explained the nature of the interaction between the mobility 1603 management service and the air interface 1605 Differences from draft-templin-atn-aero-interface-00 to draft- 1606 templin-atn-aero-interface-01: 1608 o Updates based on list review comments on IETF 'atn' list from 1609 4/29/2019 through 5/7/2019 (issue tracker established) 1611 o added list of opportunities afforded by the single virtual link 1612 model 1614 o added discussion of encapsulation considerations to Section 6 1616 o noted that DupAddrDetectTransmits is set to 0 1618 o removed discussion of IPv6 ND options for prefix assertions. The 1619 aero address already includes the MNP, and there are many good 1620 reasons for it to continue to do so. Therefore, also including 1621 the MNP in an IPv6 ND option would be redundant. 1623 o Significant re-work of "Router Discovery" section. 1625 o New Appendix B on Prefix Length considerations 1627 First draft version (draft-templin-atn-aero-interface-00): 1629 o Draft based on consensus decision of ICAO Working Group I Mobility 1630 Subgroup March 22, 2019. 1632 Authors' Addresses 1634 Fred L. Templin (editor) 1635 The Boeing Company 1636 P.O. Box 3707 1637 Seattle, WA 98124 1638 USA 1640 Email: fltemplin@acm.org 1642 Tony Whyman 1643 MWA Ltd c/o Inmarsat Global Ltd 1644 99 City Road 1645 London EC1Y 1AX 1646 England 1648 Email: tony.whyman@mccallumwhyman.com