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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: August 23, 2020 MWA Ltd c/o Inmarsat Global Ltd 6 February 20, 2020 8 Transmission of IPv6 Packets over Overlay Multilink Network (OMNI) 9 Interfaces 10 draft-templin-6man-omni-interface-01 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 August 23, 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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 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 . . . . . . . . . . . . . . . . . . . . . . . 14 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. Notification ID . . . . . . . . . . . . . . . . . . . 18 71 9. Address Mapping - Multicast . . . . . . . . . . . . . . . . . 18 72 10. Address Mapping for IPv6 Neighbor Discovery Messages . . . . 19 73 11. Conceptual Sending Algorithm . . . . . . . . . . . . . . . . 19 74 11.1. Multiple OMNI Interfaces . . . . . . . . . . . . . . . . 20 75 12. Router Discovery and Prefix Registration . . . . . . . . . . 20 76 13. AR and MSE Resilience . . . . . . . . . . . . . . . . . . . . 23 77 14. Detecting and Responding to MSE Failures . . . . . . . . . . 24 78 15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 79 16. Security Considerations . . . . . . . . . . . . . . . . . . . 25 80 17. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 25 81 18. References . . . . . . . . . . . . . . . . . . . . . . . . . 26 82 18.1. Normative References . . . . . . . . . . . . . . . . . . 26 83 18.2. Informative References . . . . . . . . . . . . . . . . . 27 84 Appendix A. Type 1 ifIndex-tuple Traffic Classifier Preference 85 Encoding . . . . . . . . . . . . . . . . . . . . . . 29 86 Appendix B. Prefix Length Considerations . . . . . . . . . . . . 31 87 Appendix C. VDL Mode 2 Considerations . . . . . . . . . . . . . 32 88 Appendix D. Change Log . . . . . . . . . . . . . . . . . . . . . 32 89 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36 91 1. Introduction 93 Mobile Nodes (MNs) (e.g., aircraft of various configurations, 94 terrestrial vehicles, seagoing vessels, mobile enterprise devices, 95 etc.) often have multiple data links for communicating with networked 96 correspondents. These data links may have diverse performance, cost 97 and availability properties that can change dynamically according to 98 mobility patterns, flight phases, proximity to infrastructure, etc. 99 MNs coordinate their data links in a discipline known as "multilink", 100 in which a single virtual interface is configured over the underlying 101 data link interfaces. 103 The MN configures a virtual interface (termed the "Overlay Multilink 104 Network (OMNI) interface") as a thin layer over the underlying access 105 network interfaces. The OMNI interface is therefore the only 106 interface abstraction exposed to the IPv6 layer and behaves according 107 to the Non-Broadcast, Multiple Access (NBMA) interface principle, 108 while underlying access network interfaces appear as link layer 109 communication channels in the architecture. The OMNI interface 110 connects to a virtual overlay service known as the "OMNI link". The 111 OMNI link spans a worldwide Internetwork that may include private-use 112 infrastructures and/or the global public Internet itself. 114 Each MN receives a Mobile Network Prefix (MNP) for numbering 115 downstream-attached End User Networks (EUNs) independently of the 116 access network data links selected for data transport. The MN 117 performs router discovery over the OMNI interface (i.e., similar to 118 IPv6 customer edge routers [RFC7084]) and acts as a mobile router on 119 behalf of its EUNs. The router discovery process is iterated over 120 each of the OMNI interface's underlying access network data links in 121 order to register per-link parameters (see Section 12). 123 The OMNI interface provides a multilink nexus for exchanging inbound 124 and outbound traffic via the correct underlying Access Network (ANET) 125 interface(s). The IPv6 layer sees the OMNI interface as a point of 126 connection to the OMNI link. Each OMNI link has one or more 127 associated Mobility Service Prefixes (MSPs) from which OMNI link MNPs 128 are derived. If there are multiple OMNI links, the IPv6 layer will 129 see multiple OMNI interfaces. 131 The OMNI interface interacts with a network-based Mobility Service 132 (MS) through IPv6 Neighbor Discovery (ND) control message exchanges 133 [RFC4861]. The MS provides Mobility Service Endpoints (MSEs) that 134 track MN movements and represent their MNPs in a global routing or 135 mapping system. 137 This document specifies the transmission of IPv6 packets [RFC8200] 138 and MN/MS control messaging over OMNI interfaces. 140 2. Terminology 142 The terminology in the normative references applies; especially, the 143 terms "link" and "interface" are the same as defined in the IPv6 144 [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) messaging is necessary. 300 o ANET interfaces do not require any L3 addresses (i.e., not even 301 link-local) in environments where communications are coordinated 302 entirely over the OMNI interface. (An alternative would be to 303 also assign the same OMNI LLA to all ANET interfaces.) 305 o as ANET interface properties change (e.g., link quality, cost, 306 availability, etc.), any active ANET interface can be used to 307 update the profiles of multiple additional ANET interfaces in a 308 single message. This allows for timely adaptation and service 309 continuity under dynamically changing conditions. 311 o coordinating ANET interfaces in this way allows them to be 312 represented in a unified MS profile with provisions for mobility 313 and multilink operations. 315 o exposing a single virtual interface abstraction to the IPv6 layer 316 allows for multilink operation (including QoS based link 317 selection, packet replication, load balancing, etc.) at L2 while 318 still permitting L3 traffic shaping based on, e.g., DSCP, flow 319 label, etc. 321 o L3 sees the OMNI interface as a point of connection to the OMNI 322 link; if there are multiple OMNI links (i.e., multiple MS's), L3 323 will see multiple OMNI interfaces. 325 Other opportunities are discussed in [RFC7847]. 327 Figure 2 depicts the architectural model for a MN connecting to the 328 MS via multiple independent ANETs. When an ANET interface becomes 329 active, the MN's OMNI interface sends native (i.e., unencapsulated) 330 IPv6 ND messages via the underlying ANET interface. IPv6 ND messages 331 traverse the ground domain ANETs until they reach an Access Router 332 (AR#1, AR#2, .., AR#n). The AR then coordinates with a Mobility 333 Service Endpoint (MSE#1, MSE#2, ..., MSE#m) in the INET and returns 334 an IPv6 ND message response to the MN. IPv6 ND messages traverse the 335 ANET at layer 2; hence, the Hop Limit is not decremented. 337 +--------------+ 338 | MN | 339 +--------------+ 340 |OMNI interface| 341 +----+----+----+ 342 +--------|IF#1|IF#2|IF#n|------ + 343 / +----+----+----+ \ 344 / | \ 345 / <---- Native | IP ----> \ 346 v v v 347 (:::)-. (:::)-. (:::)-. 348 .-(::ANET:::) .-(::ANET:::) .-(::ANET:::) 349 `-(::::)-' `-(::::)-' `-(::::)-' 350 +----+ +----+ +----+ 351 ... |AR#1| .......... |AR#2| ......... |AR#n| ... 352 . +-|--+ +-|--+ +-|--+ . 353 . | | | 354 . v v v . 355 . <----- Encapsulation -----> . 356 . . 357 . +-----+ (:::)-. . 358 . |MSE#2| .-(::::::::) +-----+ . 359 . +-----+ .-(::: INET :::)-. |MSE#m| . 360 . (::::: Routing ::::) +-----+ . 361 . `-(::: System :::)-' . 362 . +-----+ `-(:::::::-' . 363 . |MSE#1| +-----+ +-----+ . 364 . +-----+ |MSE#3| |MSE#4| . 365 . +-----+ +-----+ . 366 . . 367 . . 368 . <----- Worldwide Connected Internetwork ----> . 369 ........................................................... 371 Figure 2: MN/MS Coordination via Multiple ANETs 373 After the initial IPv6 ND message exchange, the MN can send and 374 receive unencapsulated IPv6 data packets over the OMNI interface. 375 OMNI interface multilink services will forward the packets via ARs in 376 the correct underlying ANETs. The AR encapsulates the packets 377 according to the capabilities provided by the MS and forwards them to 378 the next hop within the worldwide connected Internetwork via optimal 379 routes. 381 5. Maximum Transmission Unit (MTU) and Fragmentation 383 All IPv6 interfaces are REQUIRED to configure a minimum Maximum 384 Transmission Unit (MTU) of 1280 bytes [RFC8200]. The network 385 therefore MUST forward packets of at least 1280 bytes without 386 generating an IPv6 Path MTU Discovery (PMTUD) Packet Too Big (PTB) 387 message [RFC8201]. 389 The OMNI interface configures an MTU of 9180 bytes [RFC2492]; the 390 size is therefore not a reflection of the underlying ANET interface 391 MTUs, but rather determines the largest packet the OMNI interface can 392 forward or reassemble. 394 The OMNI interface can employ link-layer IPv6 encapsulation and 395 fragmentation/reassembly per [RFC2473], but its use is OPTIONAL since 396 correct operation will result in either case. Implementations that 397 omit link-layer IPv6 fragmentation/reassembly may be more prone to 398 dropping large packets and returning a PTB, while those that include 399 it may see improved performance at the expense of including 400 additional code. In both cases, OMNI interface neighbors are 401 responsible for advertising their willingness to reassemble. 403 The OMNI interface returns internally-generated PTB messages for 404 packets admitted into the interface that it deems too large for the 405 outbound underlying ANET interface (e.g., according to ANET 406 performance characteristics, MTU, etc). For all other packets, the 407 OMNI interface performs PMTUD even if the destination appears to be 408 on the same link since a proxy on the path could return a PTB 409 message. This ensures that the path MTU is adaptive and reflects the 410 current path used for a given data flow. 412 The MN's OMNI interface forwards packets that are no larger than the 413 MTU of the selected underlying ANET interface according to the ANET 414 L2 frame format. When the OMNI interface forwards a packet that is 415 larger than the ANET interface MTU, it drops the packet and returns a 416 PTB if the AR is not willing to reassemble. 418 Otherwise, the OMNI interface encapsulates the packet in an IPv6 419 header with source address set to the MN's link-local address and 420 destination address set to the link-local address of the MSE (see: 421 Section 7). The OMNI interface then uses IPv6 fragmentation to break 422 the encapsulated packet into fragments that are no larger than the 423 ANET interface MTU and sends the fragments over the ANET where they 424 will be intercepted by the AR. The AR then reassembles and conveys 425 the packet toward the final destination. 427 When an AR receives a fragmented or whole packet from the INET 428 destined to an ANET MN, it first determines whether to forward or 429 drop and return a PTB. If the AR deems the packet to be of 430 acceptable size, it first reassembles locally (if necessary) then 431 forwards the packet to the MN. If the (reassembled) packet is no 432 larger than the ANET MTU, the AR forwards according to the ANET L2 433 frame format. If the packet is larger than the ANET MTU, the AR 434 instead uses link-layer IPv6 encapsulation and fragmentation as above 435 if the MN accepts fragments or drops and returns a PTB otherwise. 436 The MN then reassembles and discards the encapsulation header, then 437 forwards the whole packet to the final destination. 439 Applications that cannot tolerate loss due to MTU restrictions SHOULD 440 avoid sending packets larger than 1280 bytes, since dynamic path 441 changes can reduce the path MTU at any time. Applications that may 442 benefit from sending larger packets even though the path MTU may 443 change dynamically MAY use larger sizes (i.e., up to the OMNI 444 interface MTU). 446 Note that when the AR forwards a fragmented packet received from the 447 INET, it is imperative that the AR reassembles locally first instead 448 of blindly forwarding fragments directly to the MN to avoid attacks 449 such as tiny fragments, overlapping fragments, etc. 451 6. Frame Format 453 The OMNI interface transmits IPv6 packets according to the native 454 frame format of each underlying ANET interface. For example, for 455 Ethernet-compatible interfaces the frame format is specified in 456 [RFC2464], for aeronautical radio interfaces the frame format is 457 specified in standards such as ICAO Doc 9776 (VDL Mode 2 Technical 458 Manual), for tunnels over IPv6 the frame format is specified in 459 [RFC2473], etc. 461 7. Link-Local Addresses 463 OMNI interfaces assign IPv6 Link-Local Addresses (i.e., "OMNI LLAs") 464 using the following constructs: 466 o IPv6 MN OMNI LLAs encode the most-significant 64 bits of a MNP 467 within the least-significant 64 bits (i.e., the interface ID) of a 468 Link-Local IPv6 Unicast Address (see: [RFC4291], Section 2.5.6). 469 For example, for the MNP 2001:db8:1000:2000::/56 the corresponding 470 LLA is fe80::2001:db8:1000:2000. 472 o IPv4-compatible MN OMNI LLAs are assigned as fe80::ffff:[v4addr], 473 i.e., the most significant 10 bits of the prefix fe80::/10, 474 followed by 70 '0' bits, followed by 16 '1' bits, followed by a 475 32bit IPv4 address. For example, the IPv4-Compatible MN OMNI LLA 476 for 192.0.2.1 is fe80::ffff:192.0.2.1 (also written as 477 fe80::ffff:c000:0201). 479 o MSE OMNI LLAs are assigned from the range fe80::/96, and MUST be 480 managed for uniqueness. The lower 32 bits of the LLA includes a 481 unique integer value between '1' and 'feffffff', e.g., as in 482 fe80::1, fe80::2, fe80::3, etc., fe80::feff:ffff. The address 483 fe80:: is the link-local Subnet-Router anycast address [RFC4291] 484 and the address fe80::ffff:ffff is the "All-MSEs" address. The 485 address range fe80::ff00:0000/104 is reserved for future use. 486 (Note that distinct OMNI link segments can avoid overlap by 487 assigning MSE OMNI LLAs from unique fe80::/96 sub-prefixes. For 488 example, a first segment could assign from fe80::1000/116, a 489 second from fe80::2000/116, a third from fe80::3000/116, etc.) 491 Since the prefix 0000::/8 is "Reserved by the IETF" [RFC4291], no 492 MNPs can be allocated from that block ensuring that there is no 493 possibility for overlap between the above OMNI LLA constructs. 495 Since MN OMNI LLAs are based on the distribution of administratively 496 assured unique MNPs, and since MSE OMNI LLAs are guaranteed unique 497 through administrative assignment, OMNI interfaces set the 498 autoconfiguration variable DupAddrDetectTransmits to 0 [RFC4862]. 500 8. Address Mapping - Unicast 502 OMNI interfaces maintain a neighbor cache for tracking per-neighbor 503 state and use the link-local address format specified in Section 7. 504 IPv6 Neighbor Discovery (ND) [RFC4861] messages on MN OMNI interfaces 505 observe the native Source/Target Link-Layer Address Option (S/TLLAO) 506 formats of the underlying ANET interfaces (e.g., for Ethernet the S/ 507 TLLAO is specified in [RFC2464]). 509 MNs such as aircraft typically have many wireless data link types 510 (e.g. satellite-based, cellular, terrestrial, air-to-air directional, 511 etc.) with diverse performance, cost and availability properties. 512 The OMNI interface would therefore appear to have multiple L2 513 connections, and may include information for multiple ANET interfaces 514 in a single IPv6 ND message exchange. 516 OMNI interfaces use an IPv6 ND option called the "OMNI option" 517 formatted as shown in Figure 3: 519 0 1 2 3 520 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 1 521 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 522 | Type | Length | Prefix Length |R|P|A| Reserved| 523 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 524 | | 525 ~ Sub-Options ~ 526 | | 527 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 529 Figure 3: OMNI Option Format 531 In this format: 533 o Type is set to TBD. 535 o Length is set to the number of 8 octet blocks in the option. 537 o Prefix Length is set according to the IPv6 source address type. 538 For MN OMNI LLAs, the value is set to the length of the embedded 539 MNP. For IPv4-compatible MN OMNI LLAs, the value is set to 96 540 plus the length of the embedded IPv4 prefix. For MSE OMNI LLAs, 541 the value is set to 128. 543 o R (the "Register/Release" bit) is set to '1' to register an MNP or 544 set to '0' to release a registration. 546 o P (the "Primary" bit) is set to '1' in a MN RS message to request 547 an AR to serve as primary, and set to '1' in the AR's RA message 548 to accept the primary role. Set to '0' in all other RS/RA 549 messages, and ignored in all other ND messages. 551 o A (the "Accepts Fragments" bit) is set to '1' in an RS/RA message 552 to indicate whether the sender is willing to accept OMNI interface 553 link-local fragments (see: Section 5). Nodes that are willing to 554 perform link-local reassembly set A to '1' (otherwise '0'). 556 o Reserved is set to the value '0' on transmission and ignored on 557 reception. 559 o Sub-Options is a Variable-length field, of length such that the 560 complete OMNI Option is an integer multiple of 8 octets long. 561 Contains one or more options, as described in Section 8.1. 563 8.1. Sub-Options 565 The OMNI option includes zero or more Sub-Options, some of which may 566 appear multiple times in the same message. Each consecutive Sub- 567 Option is concatenated immediately after its predecessor. All Sub- 568 Options except Pad1 (see below) are type-length-value (TLV) encoded 569 in the following format: 571 0 1 2 572 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 5 573 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 574 | Sub-Type | Sub-length | Sub-Option Data ... 575 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 577 Figure 4: Sub-Option Format 579 o Sub-Type is a 1-byte field that encodes the Sub-Option type. Sub- 580 Options defined in this document are: 582 Option Name Sub-Type 583 Pad1 0 584 PadN 1 585 ifIndex-tuple (Type 1) 2 586 ifIndex-tuple (Type 2) 3 587 Notification ID 4 589 Figure 5 591 Sub-Types 253 and 254 are reserved for experimentation, as 592 recommended in[RFC3692]]. 594 o Sub-Length is a 1-byte field that encodes the length of the Sub- 595 Option Data, in bytes 597 o Sub-Option Data is a byte string with format determined by Sub- 598 Type 600 During processing, unrecognized Sub-Options are ignored and the next 601 Sub-Option processed until the end of the OMNI option. 603 The following Sub-Option types and formats are defined in this 604 document: 606 8.1.1. Pad1 607 0 608 0 1 2 3 4 5 6 7 609 +-+-+-+-+-+-+-+-+ 610 | Sub-Type=0 | 611 +-+-+-+-+-+-+-+-+ 613 Figure 6: Pad1 615 o Sub-Type is set to 0. 617 o No Sub-Length or Sub-Option Data follows (i.e., the "Sub-Option" 618 consists of a single zero octet). 620 8.1.2. PadN 622 0 1 2 623 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 5 624 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 625 | Sub-Type=1 |Sub-length=N-2 | N-2 padding bytes ... 626 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 628 Figure 7: PadN 630 o Sub-Type is set to 1. 632 o Sub-Length is set to N-2 being the number of padding bytes that 633 follow. 635 o Sub-Option Data consists of N-2 zero-valued octets. 637 8.1.3. ifIndex-tuple (Type 1) 639 0 1 2 3 640 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 1 641 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 642 | Sub-Type=2 | Sub-length=4+N| ifIndex | ifType | 643 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 644 | Provider ID | Link |S|I|RSV| Bitmap(0)=0xff|P00|P01|P02|P03| 645 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 646 |P04|P05|P06|P07|P08|P09|P10|P11|P12|P13|P14|P15|P16|P17|P18|P19| 647 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 648 |P20|P21|P22|P23|P24|P25|P26|P27|P28|P29|P30|P31| Bitmap(1)=0xff| 649 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 650 |P32|P33|P34|P35|P36|P37|P38|P39| ... 651 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 653 Figure 8: ifIndex-tuple (Type 1) 655 o Sub-Type is set to 2. 657 o Sub-Length is set to 4+N (the number of Sub-Option Data bytes that 658 follow). 660 o Sub-Option Data contains an "ifIndex-tuple" (Type 1) encoded as 661 follows (note that the first four bytes must be present): 663 * ifIndex is set to an 8-bit integer value corresponding to a 664 specific underlying ANET interface. OMNI options MAY include 665 multiple ifIndex-tuples, and MUST number each with an ifIndex 666 value between '1' and '255' that represents a MN-specific 8-bit 667 mapping for the actual ifIndex value assigned to the ANET 668 interface by network management [RFC2863] (the ifIndex value 669 '0' is reserved for use by the MS). Multiple ifIndex-tuples 670 with the same ifIndex value MAY appear in the same OMNI option. 672 * ifType is set to an 8-bit integer value corresponding to the 673 underlying ANET interface identified by ifIndex. The value 674 represents an OMNI interface-specific 8-bit mapping for the 675 actual IANA ifType value registered in the 'IANAifType-MIB' 676 registry [http://www.iana.org]. 678 * Provider ID is set to an OMNI interface-specific 8-bit ID value 679 for the network service provider associated with this ifIndex. 681 * Link encodes a 4-bit link metric. The value '0' means the link 682 is DOWN, and the remaining values mean the link is UP with 683 metric ranging from '1' ("lowest") to '15' ("highest"). 685 * S is set to '1' if this ifIndex-tuple corresponds to the 686 underlying ANET interface that is the source of the ND message. 687 Set to '0' otherwise. 689 * I is set to '0' ("Simplex") if the index for each singleton 690 Bitmap byte in the Sub-Option Data is inferred from its 691 sequential position (i.e., 0, 1, 2, ...), or set to '1' 692 ("Indexed") if each Bitmap is preceded by an Index byte. 693 Figure 8 shows the simplex case for I set to '0'. For I set to 694 '1', each Bitmap is instead preceded by an Index byte that 695 encodes a value "i" = (0 - 255) as the index for its companion 696 Bitmap as follows: 698 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 699 | Index=i | Bitmap(i) |P[*] values ... 700 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 702 Figure 9 704 * RSV is set to the value 0 on transmission and ignored on 705 reception. 707 * The remainder of the Sub-Option Data contains N = (0 - 251) 708 bytes of traffic classifier preferences consisting of a first 709 (indexed) Bitmap (i.e., "Bitmap(i)") followed by 0-8 1-byte 710 blocks of 2-bit P[*] values, followed by a second Bitmap (i), 711 followed by 0-8 blocks of P[*] values, etc. Reading from bit 0 712 to bit 7, the bits of each Bitmap(i) that are set to '1'' 713 indicate the P[*] blocks from the range P[(i*32)] through 714 P[(i*32) + 31] that follow; if any Bitmap(i) bits are '0', then 715 the corresponding P[*] block is instead omitted. For example, 716 if Bitmap(0) contains 0xff then the block with P[00]-P[03], 717 followed by the block with P[04]-P[07], etc., and ending with 718 the block with P[28]-P[31] are included (as showin in 719 Figure 8). The next Bitmap(i) is then consulted with its bits 720 indicating which P[*] blocks follow, etc. out to the end of the 721 Sub-Option. The first 16 P[*] blocks correspond to the 64 722 Differentiated Service Code Point (DSCP) values P[00] - P[63] 723 [RFC2474]. If additional P[*] blocks follow, their values 724 correspond to "pseudo-DSCP" traffic classifier values P[64], 725 P[65], P[66], etc. See Appendix A for further discussion and 726 examples. 728 * Each 2-bit P[*] field is set to the value '0' ("disabled"), '1' 729 ("low"), '2' ("medium") or '3' ("high") to indicate a QoS 730 preference level for ANET interface selection purposes. Not 731 all P[*] values need to be included in all OMNI option 732 instances of a given ifIndex-tuple. Any P[*] values 733 represented in an earlier OMNI option but ommitted in the 734 current OMNI option remain unchanged. Any P[*] values not yet 735 represented in any OMNI option default to "medium". 737 8.1.4. ifIndex-tuple (Type 2) 739 0 1 2 3 740 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 1 741 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 742 | Sub-Type=3 | Sub-length=4+N| ifIndex | ifType | 743 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 744 | Provider ID | Link |S|Resvd| ~ 745 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ 746 ~ ~ 747 ~ RFC 6088 Format Traffic Selector ~ 748 ~ ~ 749 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 751 Figure 10: ifIndex-tuple (Type 2) 753 o Sub-Type is set to 3. 755 o Sub-Length is set to 4+N (the number of Sub-Option Data bytes that 756 follow). 758 o Sub-Option Data contains an "ifIndex-tuple" (Type 2) encoded as 759 follows (note that the first four bytes must be present): 761 * ifIndex, ifType, Provider ID, Link and S are set exactly as for 762 Type 1 ifIndex-tuples as specified in Section 8.1.3. 764 * the remainder of the Sub-Option body encodes a variable-length 765 traffic selector formatted per [RFC6088], beginning with the 766 "TS Format" field. 768 8.1.5. Notification ID 770 0 1 2 3 771 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 1 772 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 773 | Sub-Type=4 | Sub-length=4 | Notification ID (bits 0 - 15) | 774 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 775 | Notification ID (bits 16 - 32)| 776 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 778 Figure 11: Notification ID 780 o Sub-Type is set to 4. 782 o Sub-Length is set to 4. 784 o Notification ID contains the least-significant 32 bits of an MSE 785 OMNI LLA to notify (e.g., for the LLA fe80::face:cafe the field 786 contains 0xfacecafe). Valid only in MN RS messages, and ignored 787 in all other ND messages. OMNI options contain zero or more 788 Notification IDs. 790 9. Address Mapping - Multicast 792 The multicast address mapping of the native underlying ANET interface 793 applies. The mobile router on board the aircraft also serves as an 794 IGMP/MLD Proxy for its EUNs and/or hosted applications per [RFC4605] 795 while using the L2 address of the router as the L2 address for all 796 multicast packets. 798 10. Address Mapping for IPv6 Neighbor Discovery Messages 800 Per [RFC4861], IPv6 ND messages may be sent to either a multicast or 801 unicast link-scoped IPv6 destination address. However, IPv6 ND 802 messaging is coordinated between the MN and MS only without invoking 803 other nodes on the ANET. 805 For this reason, ANET links maintain unicast L2 addresses ("MSADDR") 806 for the purpose of supporting MN/MS IPv6 ND messaging. For Ethernet- 807 compatible ANETs, this specification reserves one Ethernet unicast 808 address TBD2. For non-Ethernet statically-addressed ANETs, MSADDR is 809 reserved per the assigned numbers authority for the ANET addressing 810 space. For still other ANETs, MSADDR may be dynamically discovered 811 through other means, e.g., L2 beacons. 813 MNs map the L3 addresses of all IPv6 ND messages they send (i.e., 814 both multicast and unicast) to an MSADDR instead of to an ordinary 815 unicast or multicast L2 address. In this way, all of the MN's IPv6 816 ND messages will be received by MS devices that are configured to 817 accept packets destined to MSADDR. Note that multiple MS devices on 818 the link could be configured to accept packets destined to MSADDR, 819 e.g., as a basis for supporting redundancy. 821 Therefore, ARs MUST accept and process packets destined to MSADDR, 822 while all other devices MUST NOT process packets destined to MSADDR. 823 This model has well-established operational experience in Proxy 824 Mobile IPv6 (PMIP) [RFC5213][RFC6543]. 826 11. Conceptual Sending Algorithm 828 The MN's IPv6 layer selects the outbound OMNI interface according to 829 standard IPv6 requirements when forwarding data packets from local or 830 EUN applications to external correspondents. The OMNI interface 831 maintains default routes and neighbor cache entries for MSEs, and may 832 also include additional neighbor cache entries created through other 833 means (e.g., Address Resolution, static configuration, etc.). 835 After a packet enters the OMNI interface, an outbound ANET interface 836 is selected based on multilink parameters such as DSCP, application 837 port number, cost, performance, message size, etc. OMNI interface 838 multilink selections could also be configured to perform replication 839 across multiple ANET interfaces for increased reliability at the 840 expense of packet duplication. 842 OMNI interface multilink service designers MUST observe the BCP 843 guidance in Section 15 [RFC3819] in terms of implications for 844 reordering when packets from the same flow may be spread across 845 multiple ANET interfaces having diverse properties. 847 11.1. Multiple OMNI Interfaces 849 MNs may associate with multiple MS instances concurrently. Each MS 850 instance represents a distinct OMNI link distinguished by its 851 associated MSPs. The MN configures a separate OMNI interface for 852 each link so that multiple interfaces (e.g., omni0, omni1, omni2, 853 etc.) are exposed to the IPv6 layer. 855 Depending on local policy and configuration, an MN may choose between 856 alternative active OMNI interfaces using a packet's DSCP, routing 857 information or static configuration. Interface selection based on 858 per-packet source addresses is also enabled when the MSPs for each 859 OMNI interface are known (e.g., discovered through Prefix Information 860 Options (PIOs) and/or Route Information Options (RIOs)). 862 Each OMNI interface can be configured over the same or different sets 863 of ANET interfaces. Each ANET distinguishes between the different 864 OMNI links based on the MSPs represented in per-packet IPv6 865 addresses. 867 Multiple distinct OMNI links can therefore be used to support fault 868 tolerance, load balancing, reliability, etc. The architectural model 869 parallels Layer 2 Virtual Local Area Networks (VLANs), where the MSPs 870 serve as (virtual) VLAN tags. 872 12. Router Discovery and Prefix Registration 874 ARs process IPv6 ND messages destined to All-Routers multicast 875 (ff02::2), Subnet-Router anycast (fe80::) and unicast IPv6 LLAs 876 [RFC4291]. ARs configure the L2 address MSADDR (see: Section 10) and 877 act as a proxy for MSE OMNI LLAs. 879 MNs interface with the MS by sending RS messages with OMNI options. 880 For each ANET interface, the MN sends an RS message with an OMNI 881 option, with L2 destination address set to MSADDR and with L3 882 destination address set to either a specific MSE OMNI LLA, link-local 883 Subnet-Router anycast, or All-Routers multicast. The MN discovers 884 MSE OMNI LLAs either through an RA message response to an initial 885 anycast/multicast RS or before sending an initial RS message. 886 [RFC5214] provides example MSE address discovery methods, including 887 information conveyed during data link login, name service lookups, 888 static configuration, etc. 890 The AR receives the RS messages and coordinates with the 891 corresponding MSE in a manner outside the scope of this document. 892 The AR returns an RA message with source address set to the MSE OMNI 893 LLA, with an OMNI option and with any information for the link that 894 would normally be delivered in a solicited RA message. (Note that if 895 all MSEs share common state, the AR can instead return an RA with 896 source address set to link-local Subnet-Router anycast.) 898 MNs configure OMNI interfaces that observe the properties discussed 899 in the previous section. The OMNI interface and its underlying 900 interfaces are said to be in either the "UP" or "DOWN" state 901 according to administrative actions in conjunction with the interface 902 connectivity status. An OMNI interface transitions to UP or DOWN 903 through administrative action and/or through state transitions of the 904 underlying interfaces. When a first underlying interface transitions 905 to UP, the OMNI interface also transitions to UP. When all 906 underlying interfaces transition to DOWN, the OMNI interface also 907 transitions to DOWN. 909 When an OMNI interface transitions to UP, the MN sends initial RS 910 messages to register its MNP and an initial set of underlying ANET 911 interfaces that are also UP. The MN sends additional RS messages to 912 refresh lifetimes and to register/deregister underlying ANET 913 interfaces as they transition to UP or DOWN. 915 ARs return RA messages with configuration information in response to 916 a MN's RS messages. The AR sets the RA Cur Hop Limit, M and O flags, 917 Router Lifetime, Reachable Time and Retrans Timer values as directed 918 by the MSE, and includes any necessary options such as: 920 o PIOs with (A; L=0) that include MSPs for the link [RFC8028]. 922 o RIOs [RFC4191] with more-specific routes. 924 o an MTU option that specifies the maximum acceptable packet size 925 for this ANET interface. 927 The AR coordinates with the MSE and sends immediate unicast RA 928 responses without delay; therefore, the IPv6 ND MAX_RA_DELAY_TIME and 929 MIN_DELAY_BETWEEN_RAS constants for multicast RAs do not apply. The 930 AR MAY send periodic and/or event-driven unsolicited RA messages, but 931 is not required to do so for unicast advertisements [RFC4861]. 933 The MN sends RS messages from within the OMNI interface while using 934 an UP underlying ANET interface as the outbound interface. Each RS 935 message is formatted as though it originated from the IPv6 layer, but 936 the process is coordinated wholly from within the OMNI interface and 937 is therefore opaque to the IPv6 layer. The MN sends initial RS 938 messages over an UP underlying interface with its OMNI LLA as the 939 source and with destination set as discussed above. The RS messages 940 include an OMNI option per Section 8 with a valid Prefix Length, 941 (R,P,A) flags, and with ifIndex-tuples appropriate for underlying 942 ANET interfaces. The AR processes RS message and conveys the OMNI 943 option information to the MSE. 945 When the MSE processes the OMNI information, it first validates the 946 prefix registration information. If the prefix registration was 947 valid, the MSE injects the MNP into the routing/mapping system then 948 caches the new Prefix Length, MNP and ifIndex-tuples. If the MN's 949 OMNI option included one or more Notification IDs, the new MSE also 950 notifies the former MSE(s). The MSE then directs the AR to return an 951 RA message to the MN with an OMNI option per Section 8 and with a 952 non-zero Router Lifetime if the prefix registration was successful; 953 otherwise, with a zero Router Lifetime. 955 When the MN receives the RA message, it creates a default route with 956 L3 next hop address set to the address found in the RA source address 957 and with L2 address set to MSADDR. The AR will then forward packets 958 between the MN and the MS. 960 The MN then manages its underlying ANET interfaces according to their 961 states as follows: 963 o When an underlying ANET interface transitions to UP, the MN sends 964 an RS over the ANET interface with an OMNI option. The OMNI 965 option contains at least one ifIndex-tuple with values specific to 966 this ANET interface, and may contain additional ifIndex-tuples 967 specific to this and/or other ANET interfaces. 969 o When an underlying ANET interface transitions to DOWN, the MN 970 sends an RS or unsolicited NA message over any UP ANET interface 971 with an OMNI option containing an ifIndex-tuple for the DOWN ANET 972 interface with Link set to '0'. The MN sends an RS when an 973 acknowledgement is required, or an unsolicited NA when reliability 974 is not thought to be a concern (e.g., if redundant transmissions 975 are sent on multiple ANET interfaces). 977 o When a MN wishes to release from a current MSE, it sends an RS or 978 unsolicited NA message over any UP ANET interfaces with an OMNI 979 option with R set to 0. The corresponding MSE then withdraws the 980 MNP from the routing/mapping system and (for RS responses) directs 981 the AR to return an RA message with an OMNI option and with Router 982 Lifetime set to 0. 984 o When a MN wishes to transition to a new MSE, it sends an RS or 985 unsolicited NA message over any UP ANET interfaces with an OMNI 986 option with R set to 1, with the new MSE OMNI LLA set in the 987 destination address, and (optionally) with a Notification ID 988 included for the former MSE. 990 o When all of a MNs underlying interfaces have transitioned to DOWN 991 (or if the prefix registration lifetime expires) the MSE withdraws 992 the MNP the same as if it had received a message with an OMNI 993 option with R set to 0. 995 The MN is responsible for retrying each RS exchange up to 996 MAX_RTR_SOLICITATIONS times separated by RTR_SOLICITATION_INTERVAL 997 seconds until an RA is received. If no RA is received over multiple 998 UP ANET interfaces, the MN declares this MSE unreachable and tries a 999 different MSE. 1001 The IPv6 layer sees the OMNI interface as an ordinary IPv6 interface. 1002 Therefore, when the IPv6 layer sends an RS message the OMNI interface 1003 returns an internally-generated RA message as though the message 1004 originated from an IPv6 router. The internally-generated RA message 1005 contains configuration information that is consistent with the 1006 information received from the RAs generated by the MS. 1008 Whether the OMNI interface IPv6 ND messaging process is initiated 1009 from the receipt of an RS message from the IPv6 layer is an 1010 implementation matter. Some implementations may elect to defer the 1011 IPv6 ND messaging process until an RS is received from the IPv6 1012 layer, while others may elect to initiate the process proactively. 1014 Note: The Router Lifetime value in RA messages indicates the time 1015 before which the MN must send another RS message over this underlying 1016 interface (e.g., 600 seconds), however that timescale may be 1017 significantly longer than the lifetime the MS has committed to retain 1018 the prefix registration (e.g., REACHABLETIME seconds). For this 1019 reason, the MN should select a primary AR, which is responsible for 1020 keeping the MS prefix registration alive on the MN's behalf. If the 1021 MN does not select a primary, then it must perform more frequent RS/ 1022 RA exchanges on its own behalf to refresh the MS prefix registration 1023 lifetime. 1025 13. AR and MSE Resilience 1027 ANETs SHOULD deploy ARs in Virtual Router Redundancy Protocol (VRRP) 1028 [RFC5798] configurations so that service continuity is maintained 1029 even if one or more ARs fail. Using VRRP, the MN is unaware which of 1030 the (redundant) ARs is currently providing service, and any service 1031 discontinuity will be limited to the failover time supported by VRRP. 1032 Widely deployed public domain implementations of VRRP are available. 1034 MSEs SHOULD use high availability clustering services so that 1035 multiple redundant systems can provide coordinated response to 1036 failures. As with VRRP, widely deployed public domain 1037 implementations of high availability clustering services are 1038 available. Note that special-purpose and expensive dedicated 1039 hardware is not necessary, and public domain implementations can be 1040 used even between lightweight virtual machines in cloud deployments. 1042 14. Detecting and Responding to MSE Failures 1044 In environments where fast recovery from MSE failure is required, ARs 1045 SHOULD use proactive Neighbor Unreachability Detection (NUD) in a 1046 manner that parallels Bidirectional Forwarding Detection (BFD) 1047 [RFC5880] to track MSE reachability. ARs can then quickly detect and 1048 react to failures so that cached information is re-established 1049 through alternate paths. Proactive NUD control messaging is carried 1050 only over well-connected ground domain networks (i.e., and not low- 1051 end ANET links such as aeronautical radios) and can therefore be 1052 tuned for rapid response. 1054 ARs perform proactive NUD for MSEs for which there are currently 1055 active ANET MNs. If an MSE fails, ARs can quickly inform MNs of the 1056 outage by sending multicast RA messages on the ANET interface. The 1057 AR sends RA messages to the MN via the ANET interface with source 1058 address set to the MSEs OMNI LLA, destination address set to All- 1059 Nodes multicast (ff02::1) [RFC4291], and Router Lifetime set to 0. 1061 The AR SHOULD send MAX_FINAL_RTR_ADVERTISEMENTS RA messages separated 1062 by small delays [RFC4861]. Any MNs on the ANET interface that have 1063 been using the (now defunct) MSE will receive the RA messages and 1064 associate with a new MSE. 1066 15. IANA Considerations 1068 The IANA is instructed to allocate an official Type number TBD from 1069 the registry "IPv6 Neighbor Discovery Option Formats" for the OMNI 1070 option. Implementations set Type to 253 as an interim value 1071 [RFC4727]. 1073 The OMNI option also defines an 8-bit Sub-Type field, for which IANA 1074 is instructed to create and maintain a new registry entitled "OMNI 1075 option Sub-Type values". Initial values for the OMNI option Sub-Type 1076 values registry are given below; future assignments are to be made 1077 through Expert Review [RFC8126]. 1079 Value Sub-Type name Reference 1080 ----- ------------- ---------- 1081 0 Pad1 [RFCXXXX] 1082 1 PadN [RFCXXXX] 1083 2 ifIndex-tuple (Type 1) [RFCXXXX] 1084 3 ifIndex-tuple (Type 2) [RFCXXXX] 1085 4 Notification ID [RFCXXXX] 1086 5-252 Unassigned 1087 253-254 Experimental [RFCXXXX] 1088 255 Reserved [RFCXXXX] 1090 Figure 12: OMNI Option Sub-Type Values 1092 The IANA is instructed to allocate one Ethernet unicast address TBD2 1093 (suggest 00-00-5E-00-52-14 [RFC5214]) in the registry "IANA Ethernet 1094 Address Block - Unicast Use". 1096 16. Security Considerations 1098 Security considerations for IPv6 [RFC8200] and IPv6 Neighbor 1099 Discovery [RFC4861] apply. OMNI interface IPv6 ND messages SHOULD 1100 include Nonce and Timestamp options [RFC3971] when synchronized 1101 transaction confirmation is needed. 1103 Security considerations for specific access network interface types 1104 are covered under the corresponding IP-over-(foo) specification 1105 (e.g., [RFC2464], [RFC2492], etc.). 1107 17. Acknowledgements 1109 The first version of this document was prepared per the consensus 1110 decision at the 7th Conference of the International Civil Aviation 1111 Organization (ICAO) Working Group-I Mobility Subgroup on March 22, 1112 2019. Consensus to take the document forward to the IETF was reached 1113 at the 9th Conference of the Mobility Subgroup on November 22, 2019. 1114 Attendees and contributors included: Guray Acar, Danny Bharj, 1115 Francois D'Humieres, Pavel Drasil, Nikos Fistas, Giovanni Garofolo, 1116 Bernhard Haindl, Vaughn Maiolla, Tom McParland, Victor Moreno, Madhu 1117 Niraula, Brent Phillips, Liviu Popescu, Jacky Pouzet, Aloke Roy, Greg 1118 Saccone, Robert Segers, Michal Skorepa, Michel Solery, Stephane 1119 Tamalet, Fred Templin, Jean-Marc Vacher, Bela Varkonyi, Tony Whyman, 1120 Fryderyk Wrobel and Dongsong Zeng. 1122 The following individuals are acknowledged for their useful comments: 1123 Michael Matyas, Madhu Niraula, Greg Saccone, Stephane Tamalet, Eric 1124 Vyncke. Pavel Drasil, Zdenek Jaron and Michal Skorepa are recognized 1125 for their many helpful ideas and suggestions. 1127 This work is aligned with the NASA Safe Autonomous Systems Operation 1128 (SASO) program under NASA contract number NNA16BD84C. 1130 This work is aligned with the FAA as per the SE2025 contract number 1131 DTFAWA-15-D-00030. 1133 18. References 1135 18.1. Normative References 1137 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1138 Requirement Levels", BCP 14, RFC 2119, 1139 DOI 10.17487/RFC2119, March 1997, 1140 . 1142 [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, 1143 "Definition of the Differentiated Services Field (DS 1144 Field) in the IPv4 and IPv6 Headers", RFC 2474, 1145 DOI 10.17487/RFC2474, December 1998, 1146 . 1148 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 1149 "SEcure Neighbor Discovery (SEND)", RFC 3971, 1150 DOI 10.17487/RFC3971, March 2005, 1151 . 1153 [RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and 1154 More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191, 1155 November 2005, . 1157 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 1158 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 1159 2006, . 1161 [RFC4727] Fenner, B., "Experimental Values In IPv4, IPv6, ICMPv4, 1162 ICMPv6, UDP, and TCP Headers", RFC 4727, 1163 DOI 10.17487/RFC4727, November 2006, 1164 . 1166 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 1167 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 1168 DOI 10.17487/RFC4861, September 2007, 1169 . 1171 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 1172 Address Autoconfiguration", RFC 4862, 1173 DOI 10.17487/RFC4862, September 2007, 1174 . 1176 [RFC6088] Tsirtsis, G., Giarreta, G., Soliman, H., and N. Montavont, 1177 "Traffic Selectors for Flow Bindings", RFC 6088, 1178 DOI 10.17487/RFC6088, January 2011, 1179 . 1181 [RFC8028] Baker, F. and B. Carpenter, "First-Hop Router Selection by 1182 Hosts in a Multi-Prefix Network", RFC 8028, 1183 DOI 10.17487/RFC8028, November 2016, 1184 . 1186 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1187 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1188 May 2017, . 1190 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1191 (IPv6) Specification", STD 86, RFC 8200, 1192 DOI 10.17487/RFC8200, July 2017, 1193 . 1195 [RFC8201] McCann, J., Deering, S., Mogul, J., and R. Hinden, Ed., 1196 "Path MTU Discovery for IP version 6", STD 87, RFC 8201, 1197 DOI 10.17487/RFC8201, July 2017, 1198 . 1200 18.2. Informative References 1202 [RFC2225] Laubach, M. and J. Halpern, "Classical IP and ARP over 1203 ATM", RFC 2225, DOI 10.17487/RFC2225, April 1998, 1204 . 1206 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 1207 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 1208 . 1210 [RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in 1211 IPv6 Specification", RFC 2473, DOI 10.17487/RFC2473, 1212 December 1998, . 1214 [RFC2492] Armitage, G., Schulter, P., and M. Jork, "IPv6 over ATM 1215 Networks", RFC 2492, DOI 10.17487/RFC2492, January 1999, 1216 . 1218 [RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group 1219 MIB", RFC 2863, DOI 10.17487/RFC2863, June 2000, 1220 . 1222 [RFC3692] Narten, T., "Assigning Experimental and Testing Numbers 1223 Considered Useful", BCP 82, RFC 3692, 1224 DOI 10.17487/RFC3692, January 2004, 1225 . 1227 [RFC3819] Karn, P., Ed., Bormann, C., Fairhurst, G., Grossman, D., 1228 Ludwig, R., Mahdavi, J., Montenegro, G., Touch, J., and L. 1229 Wood, "Advice for Internet Subnetwork Designers", BCP 89, 1230 RFC 3819, DOI 10.17487/RFC3819, July 2004, 1231 . 1233 [RFC4605] Fenner, B., He, H., Haberman, B., and H. Sandick, 1234 "Internet Group Management Protocol (IGMP) / Multicast 1235 Listener Discovery (MLD)-Based Multicast Forwarding 1236 ("IGMP/MLD Proxying")", RFC 4605, DOI 10.17487/RFC4605, 1237 August 2006, . 1239 [RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V., 1240 Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", 1241 RFC 5213, DOI 10.17487/RFC5213, August 2008, 1242 . 1244 [RFC5214] Templin, F., Gleeson, T., and D. Thaler, "Intra-Site 1245 Automatic Tunnel Addressing Protocol (ISATAP)", RFC 5214, 1246 DOI 10.17487/RFC5214, March 2008, 1247 . 1249 [RFC5798] Nadas, S., Ed., "Virtual Router Redundancy Protocol (VRRP) 1250 Version 3 for IPv4 and IPv6", RFC 5798, 1251 DOI 10.17487/RFC5798, March 2010, 1252 . 1254 [RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection 1255 (BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010, 1256 . 1258 [RFC6543] Gundavelli, S., "Reserved IPv6 Interface Identifier for 1259 Proxy Mobile IPv6", RFC 6543, DOI 10.17487/RFC6543, May 1260 2012, . 1262 [RFC7084] Singh, H., Beebee, W., Donley, C., and B. Stark, "Basic 1263 Requirements for IPv6 Customer Edge Routers", RFC 7084, 1264 DOI 10.17487/RFC7084, November 2013, 1265 . 1267 [RFC7421] Carpenter, B., Ed., Chown, T., Gont, F., Jiang, S., 1268 Petrescu, A., and A. Yourtchenko, "Analysis of the 64-bit 1269 Boundary in IPv6 Addressing", RFC 7421, 1270 DOI 10.17487/RFC7421, January 2015, 1271 . 1273 [RFC7847] Melia, T., Ed. and S. Gundavelli, Ed., "Logical-Interface 1274 Support for IP Hosts with Multi-Access Support", RFC 7847, 1275 DOI 10.17487/RFC7847, May 2016, 1276 . 1278 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 1279 Writing an IANA Considerations Section in RFCs", BCP 26, 1280 RFC 8126, DOI 10.17487/RFC8126, June 2017, 1281 . 1283 Appendix A. Type 1 ifIndex-tuple Traffic Classifier Preference Encoding 1285 Adaptation of the OMNI option Type 1 ifIndex-tuple's traffic 1286 classifier Bitmap to specific Internetworks such as the Aeronautical 1287 Telecommunications Network with Internet Protocol Services (ATN/IPS) 1288 may include link selection preferences based on other traffic 1289 classifiers (e.g., transport port numbers, etc.) in addition to the 1290 existing DSCP-based preferences. Nodes on specific Internetworks 1291 maintain a map of traffic classifiers to additional P[*] preference 1292 fields beyond the first 64. For example, TCP port 22 maps to P[67], 1293 TCP port 443 maps to P[70], UDP port 8060 maps to P[76], etc. 1295 Implementations use Simplex or Indexed encoding formats for P[*] 1296 encoding in order to encode a given set of traffic classifiers in the 1297 most efficient way. Some use cases may be more efficiently coded 1298 using Simplex form, while others may be more efficient using Indexed. 1299 Once a format is selected for preparation of a single ifIndex-tuple 1300 the same format must be used for the entire Sub-Option. Different 1301 Sub-Options may use different formats. 1303 The following figures show coding examples for various Simplex and 1304 Indexed formats: 1306 0 1 2 3 1307 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 1308 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1309 | Sub-Type=2 | Sub-length=4+N| ifIndex | ifType | 1310 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1311 | Provider ID | Link |S|0|RSV| Bitmap(0)=0xff|P00|P01|P02|P03| 1312 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1313 |P04|P05|P06|P07|P08|P09|P10|P11|P12|P13|P14|P15|P16|P17|P18|P19| 1314 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1315 |P20|P21|P22|P23|P24|P25|P26|P27|P28|P29|P30|P31| Bitmap(1)=0xff| 1316 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1317 |P32|P33|P34|P35|P36|P37|P38|P39|P40|P41|P42|P43|P44|P45|P46|P47| 1318 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1319 |P48|P49|P50|P51|P52|P53|P54|P55|P56|P57|P58|P59|P60|P61|P62|P63| 1320 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1321 | Bitmap(2)=0xff|P64|P65|P67|P68| ... 1322 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 1324 Figure 13: Example 1: Dense Simplex Encoding 1326 0 1 2 3 1327 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 1328 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1329 | Sub-Type=2 | Sub-length=4+N| ifIndex | ifType | 1330 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1331 | Provider ID | Link |S|0|RSV| Bitmap(0)=0x00| Bitmap(1)=0x0f| 1332 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1333 |P48|P49|P50|P51|P52|P53|P54|P55|P56|P57|P58|P59|P60|P61|P62|P63| 1334 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1335 | Bitmap(2)=0x00| Bitmap(3)=0x00| Bitmap(4)=0x00| Bitmap(5)=0x00| 1336 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1337 | Bitmap(6)=0xf0|192|193|194|195|196|197|198|199|200|201|202|203| 1338 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1339 |204|205|206|207| Bitmap(7)=0x00| Bitmap(8)=0x0f|272|273|274|275| 1340 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1341 |276|277|278|279|280|281|282|283|284|285|286|287| Bitmap(9)=0x00| 1342 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1343 |Bitmap(10)=0x00| ... 1344 +-+-+-+-+-+-+-+-+-+-+- 1346 Figure 14: Example 2: Sparse Simplex Encoding 1348 0 1 2 3 1349 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 1350 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1351 | Sub-Type=2 | Sub-length=4+N| ifIndex | ifType | 1352 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1353 | Provider ID | Link |S|1|RSV| Index = 0x00 | Bitmap = 0x80 | 1354 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1355 |P00|P01|P02|P03| Index = 0x01 | Bitmap = 0x01 |P60|P61|P62|P63| 1356 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1357 | Index = 0x10 | Bitmap = 0x80 |512|513|514|515| Index = 0x18 | 1358 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1359 | Bitmap = 0x01 |796|797|798|799| ... 1360 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 1362 Figure 15: Example 3: Indexed Encoding 1364 Appendix B. Prefix Length Considerations 1366 The 64-bit boundary in IPv6 addresses [RFC7421] determines the MN 1367 OMNI LLA format for encoding the most-significant 64 MNP bits into 1368 the least-significant 64 bits of the prefix fe80::/64 as discussed in 1369 Section 7. 1371 [RFC4291] defines the link-local address format as the most 1372 significant 10 bits of the prefix fe80::/10, followed by 54 unused 1373 bits, followed by the least-significant 64 bits of the address. If 1374 the 64-bit boundary is relaxed through future standards activity, 1375 then the 54 unused bits can be employed for extended coding of MNPs 1376 of length /65 up to /118. 1378 The extended coding format would continue to encode MNP bits 0-63 in 1379 bits 64-127 of the OMNI LLA, while including MNP bits 64-117 in bits 1380 10-63. For example, the OMNI LLA corresponding to the MNP 1381 2001:db8:1111:2222:3333:4444:5555::/112 would be 1382 fe8c:ccd1:1115:5540:2001:db8:1111:2222/128, and would still be a 1383 valid IPv6 LLA per [RFC4291]. However, a prefix length shorter than 1384 /128 cannot be applied due to the non-sequential byte ordering. 1386 Note that if the 64-bit boundary were relaxed an alternate form of 1387 OMNI LLA construction could be employed by embedding the MNP 1388 beginning with the most significant bit immediately following bit 10 1389 of the prefix fe80::/10. For example, the OMNI LLA corresponding to 1390 the MNP 2001:db8:1111:2222:3333:4444:5555::/112 would be written as 1391 fe88:0043:6e04:4448:888c:ccd1:1115:5540/122. This alternate form may 1392 provide a more natural coding for the MS along with the ability to 1393 apply a fully-qualified prefix length. It has the disadvantages of 1394 requiring an unweildy 10-bit right-shift of a 16byte address, as well 1395 as presenting a non-human-readable form. 1397 Appendix C. VDL Mode 2 Considerations 1399 ICAO Doc 9776 is the "Technical Manual for VHF Data Link Mode 2" 1400 (VDLM2) that specifies an essential radio frequency data link service 1401 for aircraft and ground stations in worldwide civil aviation air 1402 traffic management. The VDLM2 link type is "multicast capable" 1403 [RFC4861], but with considerable differences from common multicast 1404 links such as Ethernet and IEEE 802.11. 1406 First, the VDLM2 link data rate is only 31.5Kbps - multiple orders of 1407 magnitude less than most modern wireless networking gear. Second, 1408 due to the low available link bandwidth only VDLM2 ground stations 1409 (i.e., and not aircraft) are permitted to send broadcasts, and even 1410 so only as compact layer 2 "beacons". Third, aircraft employ the 1411 services of ground stations by performing unicast RS/RA exchanges 1412 upon receipt of beacons instead of listening for multicast RA 1413 messages and/or sending multicast RS messages. 1415 This beacon-oriented unicast RS/RA approach is necessary to conserve 1416 the already-scarce available link bandwidth. Moreover, since the 1417 numbers of beaconing ground stations operating within a given spatial 1418 range must be kept as sparse as possible, it would not be feasible to 1419 have different classes of ground stations within the same region 1420 observing different protocols. It is therefore highly desirable that 1421 all ground stations observe a common language of RS/RA as specified 1422 in this document. 1424 Note that links of this nature may benefit from compression 1425 techniques that reduce the bandwidth necessary for conveying the same 1426 amount of data. The IETF lpwan working group is considering possible 1427 alternatives: [https://datatracker.ietf.org/wg/lpwan/documents]. 1429 Appendix D. Change Log 1431 << RFC Editor - remove prior to publication >> 1433 Differences from draft-templin-6man-omni-interface-00 to draft- 1434 templin-6man-omni-interface-01: 1436 o "All-MSEs" OMNI LLA defined. Also reserverd fe80::ff00:0000/104 1437 for future use (most likely as "pseudo-multicast"). 1439 o Non-normative discussion of alternate OMNI LLA construction form 1440 made possible if the 64-bit assumption were relaxed. 1442 Differences from draft-templin-atn-aero-interface-21 to draft- 1443 templin-6man-omni-interface-00: 1445 o Minor clarification on Type-2 ifIndex-tuple encoding. 1447 o Draft filename change (replaces draft-templin-atn-aero-interface). 1449 Differences from draft-templin-atn-aero-interface-20 to draft- 1450 templin-atn-aero-interface-21: 1452 o OMNI option format 1454 o MTU 1456 Differences from draft-templin-atn-aero-interface-19 to draft- 1457 templin-atn-aero-interface-20: 1459 o MTU 1461 Differences from draft-templin-atn-aero-interface-18 to draft- 1462 templin-atn-aero-interface-19: 1464 o MTU 1466 Differences from draft-templin-atn-aero-interface-17 to draft- 1467 templin-atn-aero-interface-18: 1469 o MTU and RA configuration information updated. 1471 Differences from draft-templin-atn-aero-interface-16 to draft- 1472 templin-atn-aero-interface-17: 1474 o New "Primary" flag in OMNI option. 1476 Differences from draft-templin-atn-aero-interface-15 to draft- 1477 templin-atn-aero-interface-16: 1479 o New note on MSE OMNI LLA uniqueness assurance. 1481 o General cleanup. 1483 Differences from draft-templin-atn-aero-interface-14 to draft- 1484 templin-atn-aero-interface-15: 1486 o General cleanup. 1488 Differences from draft-templin-atn-aero-interface-13 to draft- 1489 templin-atn-aero-interface-14: 1491 o General cleanup. 1493 Differences from draft-templin-atn-aero-interface-12 to draft- 1494 templin-atn-aero-interface-13: 1496 o Minor re-work on "Notify-MSE" (changed to Notification ID). 1498 Differences from draft-templin-atn-aero-interface-11 to draft- 1499 templin-atn-aero-interface-12: 1501 o Removed "Request/Response" OMNI option formats. Now, there is 1502 only one OMNI option format that applies to all ND messages. 1504 o Added new OMNI option field and supporting text for "Notify-MSE". 1506 Differences from draft-templin-atn-aero-interface-10 to draft- 1507 templin-atn-aero-interface-11: 1509 o Changed name from "aero" to "OMNI" 1511 o Resolved AD review comments from Eric Vyncke (posted to atn list) 1513 Differences from draft-templin-atn-aero-interface-09 to draft- 1514 templin-atn-aero-interface-10: 1516 o Renamed ARO option to AERO option 1518 o Re-worked Section 13 text to discuss proactive NUD. 1520 Differences from draft-templin-atn-aero-interface-08 to draft- 1521 templin-atn-aero-interface-09: 1523 o Version and reference update 1525 Differences from draft-templin-atn-aero-interface-07 to draft- 1526 templin-atn-aero-interface-08: 1528 o Removed "Classic" and "MS-enabled" link model discussion 1530 o Added new figure for MN/AR/MSE model. 1532 o New Section on "Detecting and responding to MSE failure". 1534 Differences from draft-templin-atn-aero-interface-06 to draft- 1535 templin-atn-aero-interface-07: 1537 o Removed "nonce" field from AR option format. Applications that 1538 require a nonce can include a standard nonce option if they want 1539 to. 1541 o Various editorial cleanups. 1543 Differences from draft-templin-atn-aero-interface-05 to draft- 1544 templin-atn-aero-interface-06: 1546 o New Appendix C on "VDL Mode 2 Considerations" 1548 o New Appendix D on "RS/RA Messaging as a Single Standard API" 1550 o Various significant updates in Section 5, 10 and 12. 1552 Differences from draft-templin-atn-aero-interface-04 to draft- 1553 templin-atn-aero-interface-05: 1555 o Introduced RFC6543 precedent for focusing IPv6 ND messaging to a 1556 reserved unicast link-layer address 1558 o Introduced new IPv6 ND option for Aero Registration 1560 o Specification of MN-to-MSE message exchanges via the ANET access 1561 router as a proxy 1563 o IANA Considerations updated to include registration requests and 1564 set interim RFC4727 option type value. 1566 Differences from draft-templin-atn-aero-interface-03 to draft- 1567 templin-atn-aero-interface-04: 1569 o Removed MNP from aero option format - we already have RIOs and 1570 PIOs, and so do not need another option type to include a Prefix. 1572 o Clarified that the RA message response must include an aero option 1573 to indicate to the MN that the ANET provides a MS. 1575 o MTU interactions with link adaptation clarified. 1577 Differences from draft-templin-atn-aero-interface-02 to draft- 1578 templin-atn-aero-interface-03: 1580 o Sections re-arranged to match RFC4861 structure. 1582 o Multiple aero interfaces 1584 o Conceptual sending algorithm 1586 Differences from draft-templin-atn-aero-interface-01 to draft- 1587 templin-atn-aero-interface-02: 1589 o Removed discussion of encapsulation (out of scope) 1591 o Simplified MTU section 1593 o Changed to use a new IPv6 ND option (the "aero option") instead of 1594 S/TLLAO 1596 o Explained the nature of the interaction between the mobility 1597 management service and the air interface 1599 Differences from draft-templin-atn-aero-interface-00 to draft- 1600 templin-atn-aero-interface-01: 1602 o Updates based on list review comments on IETF 'atn' list from 1603 4/29/2019 through 5/7/2019 (issue tracker established) 1605 o added list of opportunities afforded by the single virtual link 1606 model 1608 o added discussion of encapsulation considerations to Section 6 1610 o noted that DupAddrDetectTransmits is set to 0 1612 o removed discussion of IPv6 ND options for prefix assertions. The 1613 aero address already includes the MNP, and there are many good 1614 reasons for it to continue to do so. Therefore, also including 1615 the MNP in an IPv6 ND option would be redundant. 1617 o Significant re-work of "Router Discovery" section. 1619 o New Appendix B on Prefix Length considerations 1621 First draft version (draft-templin-atn-aero-interface-00): 1623 o Draft based on consensus decision of ICAO Working Group I Mobility 1624 Subgroup March 22, 2019. 1626 Authors' Addresses 1628 Fred L. Templin (editor) 1629 The Boeing Company 1630 P.O. Box 3707 1631 Seattle, WA 98124 1632 USA 1634 Email: fltemplin@acm.org 1635 Tony Whyman 1636 MWA Ltd c/o Inmarsat Global Ltd 1637 99 City Road 1638 London EC1Y 1AX 1639 England 1641 Email: tony.whyman@mccallumwhyman.com