idnits 2.17.1 draft-ietf-intarea-provisioning-domains-08.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (October 08, 2019) is 1662 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 4941 (Obsoleted by RFC 8981) -- Obsolete informational reference (is this intentional?): RFC 2818 (Obsoleted by RFC 9110) -- Obsolete informational reference (is this intentional?): RFC 7049 (Obsoleted by RFC 8949) Summary: 1 error (**), 0 flaws (~~), 1 warning (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group P. Pfister 3 Internet-Draft E. Vyncke 4 Intended status: Standards Track Cisco 5 Expires: April 10, 2020 T. Pauly 6 Apple Inc. 7 D. Schinazi 8 Google LLC 9 W. Shao 10 Cisco 11 October 08, 2019 13 Discovering Provisioning Domain Names and Data 14 draft-ietf-intarea-provisioning-domains-08 16 Abstract 18 Provisioning Domains (PvDs) are defined as consistent sets of network 19 configuration information. This allows hosts to manage connections 20 to multiple networks and interfaces simultaneously, such as when a 21 home router provides connectivity through both a broadband and 22 cellular network provider. 24 This document defines a mechanism for explicitly identifying PvDs 25 through a Router Advertisement (RA) option. This RA option announces 26 a PvD identifier, which hosts can compare to differentiate between 27 PvDs. The option can directly carry some information about a PvD and 28 can optionally point to additional PvD information that can be 29 retrieved using HTTP over TLS. 31 Status of This Memo 33 This Internet-Draft is submitted in full conformance with the 34 provisions of BCP 78 and BCP 79. 36 Internet-Drafts are working documents of the Internet Engineering 37 Task Force (IETF). Note that other groups may also distribute 38 working documents as Internet-Drafts. The list of current Internet- 39 Drafts is at https://datatracker.ietf.org/drafts/current/. 41 Internet-Drafts are draft documents valid for a maximum of six months 42 and may be updated, replaced, or obsoleted by other documents at any 43 time. It is inappropriate to use Internet-Drafts as reference 44 material or to cite them other than as "work in progress." 46 This Internet-Draft will expire on April 10, 2020. 48 Copyright Notice 50 Copyright (c) 2019 IETF Trust and the persons identified as the 51 document authors. All rights reserved. 53 This document is subject to BCP 78 and the IETF Trust's Legal 54 Provisions Relating to IETF Documents 55 (https://trustee.ietf.org/license-info) in effect on the date of 56 publication of this document. Please review these documents 57 carefully, as they describe your rights and restrictions with respect 58 to this document. Code Components extracted from this document must 59 include Simplified BSD License text as described in Section 4.e of 60 the Trust Legal Provisions and are provided without warranty as 61 described in the Simplified BSD License. 63 Table of Contents 65 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 66 1.1. Specification of Requirements . . . . . . . . . . . . . . 4 67 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 68 3. Provisioning Domain Identification using Router 69 Advertisements . . . . . . . . . . . . . . . . . . . . . . . 5 70 3.1. PvD ID Option for Router Advertisements . . . . . . . . . 5 71 3.2. Router Behavior . . . . . . . . . . . . . . . . . . . . . 8 72 3.3. Non-PvD-aware Host Behavior . . . . . . . . . . . . . . . 9 73 3.4. PvD-aware Host Behavior . . . . . . . . . . . . . . . . . 9 74 3.4.1. DHCPv6 configuration association . . . . . . . . . . 10 75 3.4.2. DHCPv4 configuration association . . . . . . . . . . 10 76 3.4.3. Connection Sharing by the Host . . . . . . . . . . . 11 77 3.4.4. Usage of DNS Servers . . . . . . . . . . . . . . . . 12 78 4. Provisioning Domain Additional Information . . . . . . . . . 12 79 4.1. Retrieving the PvD Additional Information . . . . . . . . 13 80 4.2. Operational Consideration to Providing the PvD Additional 81 Information . . . . . . . . . . . . . . . . . . . . . . . 15 82 4.3. PvD Additional Information Format . . . . . . . . . . . . 15 83 4.3.1. Example . . . . . . . . . . . . . . . . . . . . . . . 17 84 4.4. Detecting misconfiguration and misuse . . . . . . . . . . 17 85 5. Operational Considerations . . . . . . . . . . . . . . . . . 18 86 5.1. Exposing Extra RA Options to PvD-Aware Hosts . . . . . . 18 87 5.2. Different RAs for PvD-Aware and Non-PvD-Aware Hosts . . . 18 88 5.3. Enabling Multi-homing for PvD-Aware Hosts . . . . . . . . 20 89 6. Security Considerations . . . . . . . . . . . . . . . . . . . 21 90 7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 21 91 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22 92 8.1. New entry in the Well-Known URIs Registry . . . . . . . . 22 93 8.2. Additional Information PvD Keys Registry . . . . . . . . 22 94 8.3. PvD Option Flags Registry . . . . . . . . . . . . . . . . 22 95 8.4. PvD JSON Media Type Registration . . . . . . . . . . . . 23 97 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 23 98 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 24 99 10.1. Normative References . . . . . . . . . . . . . . . . . . 24 100 10.2. Informative References . . . . . . . . . . . . . . . . . 25 101 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27 103 1. Introduction 105 Provisioning Domains (PvDs) are defined in [RFC7556] as consistent 106 sets of network configuration information. This information includes 107 properties that are traditionally associated with a single networking 108 interface, such as source addresses, DNS configuration, proxy 109 configuration, and gateway addresses. 111 Clients that are aware of PvDs can take advantage of multiple network 112 interfaces simultaneously. This enables using two PvDs in parallel 113 for separate connections or for multi-path transports. 115 While most PvDs today are discovered implicitly (such as by receiving 116 information via Router Advertisements from a router on a network that 117 a client host directly connects to), [RFC7556] also defines the 118 notion of Explicit PvDs. IPsec Virtual Private Networks are 119 considered Explicit PvDs, but Explicit PvDs can also be discovered 120 via the local network router. Discovering Explicit PvDs allows two 121 key advancements in managing multiple PvDs: 123 1. The ability to discover and use multiple PvDs on a single 124 interface, such as when a local router can provide connectivity 125 to two different Internet Service Providers. 127 2. The ability to associate additional informations about PvDs to 128 describe the properties of the network. 130 While [RFC7556] defines the concept of Explicit PvDs, it does not 131 define the mechanism for discovering multiple Explicit PvDs on a 132 single network and their additional information. 134 This document specifies a way to identify PvDs with Fully Qualified 135 Domain Names (FQDN), called PvD IDs. Those identifiers are 136 advertised in a new Router Advertisement (RA) [RFC4861] option called 137 the PvD ID Router Advertisement option which, when present, 138 associates the PvD ID with all the information present in the Router 139 Advertisement as well as any configuration object, such as addresses, 140 deriving from it. The PVD ID Router Advertisement option may also 141 contain a set of other RA options. Since such options are only 142 considered by hosts implementing this specification, network 143 operators may configure hosts that are 'PvD-aware' with PvDs that are 144 ignored by other hosts. 146 Since PvD IDs are used to identify different ways to access the 147 internet, multiple PvDs (with different PvD IDs) can be provisioned 148 on a single host interface. Similarly, the same PvD ID could be used 149 on different interfaces of a host in order to inform that those PvDs 150 ultimately provide equivalent services. 152 This document also introduces a mechanism for hosts to retrieve 153 optional additional information related to a specific PvD by means of 154 an HTTP over TLS query using an URI derived from the PvD ID. The 155 retrieved JSON object contains additional information that would 156 typically be considered too large to be directly included in the 157 Router Advertisement, but might be considered useful to the 158 applications, or even sometimes users, when choosing which PvD should 159 be used. 161 For example, if Alice has both a cellular network provider and a 162 broadband provider in her home, her PvD-aware devices and 163 applications would be aware of both available uplinks. These 164 applications could fail-over between these networks, or run 165 connections over both (potentially using multi-path transports). 166 Applications could also select specific uplinks based on the 167 properties of the network; for example, if the cellular network 168 provides free high-quality video streaming, a video-streaming 169 application could select that network while most of the other traffic 170 on Alice's device uses the broadband provider. 172 1.1. Specification of Requirements 174 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 175 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 176 "OPTIONAL" in this document are to be interpreted as described in BCP 177 14 [RFC2119] [RFC8174] when, and only when, they appear in all 178 capitals, as shown here. 180 2. Terminology 182 This document uses the following terminology: 184 Provisioning Domain (PvD): A set of network configuration 185 information; for more information, see [RFC7556]. 187 PvD ID: A Fully Qualified Domain Name (FQDN) used to identify a PvD. 189 Explicit PvD: A PvD uniquely identified with a PvD ID. For more 190 information, see [RFC7556]. 192 Implicit PvD: A PvD that, in the absence of a PvD ID, is identified 193 by the host interface to which it is attached and the address of 194 the advertising router. See also [RFC7556]. 196 PvD-aware host: A host that supports the association of network 197 configuration information into PvDs and the use of these PvDs as 198 described in this document. Also named PvD-aware node in 199 [RFC7556]. 201 3. Provisioning Domain Identification using Router Advertisements 203 Explicit PvDs are identified by a PvD ID. The PvD ID is a Fully 204 Qualified Domain Name (FQDN) which MUST belong to the network 205 operator in order to avoid naming collisions. The same PvD ID MAY be 206 used in several access networks when they ultimately provide 207 identical services (e.g., in all home networks subscribed to the same 208 service); else, the PvD ID MUST be different to follow Section 2.4 of 209 [RFC7556]. 211 3.1. PvD ID Option for Router Advertisements 213 This document introduces a Router Advertisement (RA) option called 214 PvD Option. It is used to convey the FQDN identifying a given PvD 215 (see Figure 1), bind the PvD ID with configuration information 216 received over DHCPv4 (see Section 3.4.2), enable the use of HTTP over 217 TLS to retrieve the PvD Additional Information JSON object (see 218 Section 4), as well as contain any other RA options which would 219 otherwise be valid in the RA. 221 0 1 2 3 222 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 1 223 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 224 | Type | Length |H|L|R| Reserved | Delay | 225 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 226 | Sequence Number | ... 227 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ... 228 ... PvD ID FQDN ... 229 ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 230 ... | Padding | 231 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 232 | ... 233 ... Router Advertisement message header ... 234 ... (Only present when R-flag is set) ... 235 ... | 236 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 237 | Options ... 238 +-+-+-+-+-+-+-+-+-+-+-+- 240 Figure 1: PvD ID Router Advertisements Option Format 242 Type: (8 bits) Set to 21. 244 Length: (8 bits) The length of the option in units of 8 octets, 245 including the Type and Length fields, the Router Advertisement 246 message header, if any, as well as the RA options that are 247 included within the PvD Option. 249 H-flag: (1 bit) 'HTTP' flag stating whether some PvD Additional 250 Information is made available through HTTP over TLS, as described 251 in Section 4. 253 L-flag: (1 bit) 'Legacy' flag stating whether the router is also 254 providing IPv4 information using DHCPv4 (see Section 3.4.2). 256 R-flag: (1 bit) 'Router Advertisement' flag stating whether the PvD 257 Option is followed (right after padding to the next 64 bits 258 boundary) by a Router Advertisement message header (See section 259 4.2 of [RFC4861]). 261 Reserved: (13 bits) Reserved for later use. It MUST be set to zero 262 by the sender and ignored by the receiver. 264 Delay: (4 bits) Unsigned integer used to delay HTTP GET queries from 265 hosts by a randomized backoff (see Section 4.1). 267 Sequence Number: (16 bits) Sequence number for the PvD Additional 268 Information, as described in Section 4. 270 PvD ID FQDN: The FQDN used as PvD ID encoded in DNS format, as 271 described in Section 3.1 of [RFC1035]. Domain names compression 272 described in Section 4.1.4 of [RFC1035] MUST NOT be used. 274 Padding: Zero or more padding octets to the next 8 octet boundary 275 (see Section 4.6 of [RFC4861]). It MUST be set to zero by the 276 sender, and ignored by the receiver. 278 RA message header: (16 octets) When the R-flag is set, a full Router 279 Advertisement message header as specified in [RFC4861]. The 280 sender MUST set the 'Type' to 134, the value for "Router 281 Advertisement", and set the 'Code' to 0. Receivers MUST ignore 282 both of these fields. The 'Checksum' MUST be set to 0 by the 283 sender; non-zero checksums MUST be ignored by the receiver. All 284 other fields are to be set and parsed as specified in [RFC4861] or 285 any updating documents. 287 Options: Zero or more RA options that would otherwise be valid as 288 part of the Router Advertisement main body, but are instead 289 included in the PvD Option so as to be ignored by hosts that are 290 not PvD-aware. 292 Here is an example of a PvD Option with "example.org" as the PvD ID 293 FQDN and including both an RDNSS option and a prefix information 294 option. It has a Sequence Number of 123, and indicates the presence 295 of additional information that is expected to be fetched with a delay 296 factor of 5. 298 0 1 2 3 299 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 1 300 +---------------+-----------------------------------------------+ 301 | Type: 21 | Length: 12 |1|0|0| Reserved |Delay:5| 302 +---------------+-------------------------------+---------------+ 303 | Seq number: 123 | 7 | e | 304 +---------------+-----------------------------------------------+ 305 | x | a | m | p | 306 +---------------------------------------------------------------+ 307 | l | e | 3 | o | 308 +---------------------------------------------------------------+ 309 | r | g | 0 | 0 (padding) | 310 +---------------------------------------------------------------+ 311 | 0 (padding) | 0 (padding) | 0 (padding) | 0 (padding) | 312 +---------------+---------------+---------------+---------------+ 313 | RDNSS option (RFC 6106) length: 5 ... 314 ... ... 315 ... | 316 +---------------------------------------------------------------+ 317 | Prefix Information Option (RFC 4861) length: 4 ... 318 ... | 319 ... | 320 +---------------------------------------------------------------+ 322 Figure 2 324 3.2. Router Behavior 326 A router MAY send RAs containing one PvD Option, but MUST NOT include 327 more than one PvD Option in each RA. The PvD Option MUST NOT contain 328 further PvD Options. 330 The PvD Option MAY contain zero, one, or more RA options which would 331 otherwise be valid as part of the same RA. Such options are 332 processed by PvD-aware hosts, while ignored by other hosts per 333 section 4.2 of [RFC4861]. 335 In order to provide multiple different PvDs, a router MUST send 336 multiple RAs. If more than one different Implicit PvDs are 337 advertised, the RAs MUST be sent from different link-local source 338 addresses. Explicit PvDs MAY share link-local source addresses with 339 an Implicit PvD and any number of other Explicit PvDs. 341 In other words, different Explicit PvDs MAY be advertised with RAs 342 using the same link-local source address; but different Implicit 343 PvDs, advertised by different RAs, MUST use different link-local 344 addresses because these Implicit PvDs are identified by the source 345 addresses of the RAs. 347 As specified in [RFC4861], when the set of options causes the size of 348 an advertisement to exceed the link MTU, multiple router 349 advertisements can be sent, each containing a subset of the options. 350 In such cases, the PvD Option header (i.e., all fields except the 351 'Options' field) MUST be repeated in all the transmitted RAs. The 352 options within the 'Options' field, MAY be transmitted only once, 353 included in one of the transmitted PvD Options. 355 3.3. Non-PvD-aware Host Behavior 357 As the PvD Option has a new option code, non-PvD-aware hosts will 358 simply ignore the PvD Option and all the options it contains (see 359 section 4.2 of [RFC4861]. This ensure the backward compatibility 360 required in Section 3.3 of [RFC7556]. This behavior allows for a 361 mixed-mode network with a mix of PvD-aware and non-PvD-aware hosts 362 coexist. 364 3.4. PvD-aware Host Behavior 366 Hosts MUST associate received RAs and included configuration 367 information (e.g., Router Valid Lifetime, Prefix Information 368 [RFC4861], Recursive DNS Server [RFC8106], Routing Information 369 [RFC4191] options) with the Explicit PvD identified by the first PvD 370 Option present in the received RA, if any, or with the Implicit PvD 371 identified by the host interface and the source address of the 372 received RA otherwise. 374 In case multiple PvD Options are found in a given RA, hosts MUST 375 ignore all but the first PvD Option. 377 If a host receives PvD Options flags that it does not recognize 378 (currently in the Reserved field), it MUST ignore these flags. 380 Similarly, hosts MUST associate all network configuration objects 381 (e.g., default routers, addresses, more specific routes, DNS 382 Recursive Resolvers) with the PvD associated with the RA which last 383 updated the object. For example, addresses that are generated using 384 a received Prefix Information option (PIO) are associated with the 385 PvD of the last received RA which included the given PIO. 387 PvD IDs MUST be compared in a case-insensitive manner as defined by 388 [RFC4343]. For example, "pvd.example.com." or "PvD.Example.coM." 389 would refer to the same PvD. 391 While resolving names, executing the default address selection 392 algorithm [RFC6724] or executing the default router selection 393 algorithm when forwarding packets ([RFC4861], [RFC4191] and 395 [RFC8028]), hosts and applications MAY consider only the 396 configuration associated with any non-empty subset of PvDs. 398 For example, a host MAY associate a given process with a specific 399 PvD, or a specific set of PvDs, while associating another process 400 with another PvD. A PvD-aware application might also be able to 401 select, on a per-connection basis, which PvDs should be used. In 402 particular, constrained devices such as small battery operated 403 devices (e.g. IoT), or devices with limited CPU or memory resources 404 may purposefully use a single PvD while ignoring some received RAs 405 containing different PvD IDs. 407 The way an application expresses its desire to use a given PvD, or a 408 set of PvDs, or the way this selection is enforced, is out of the 409 scope of this document. Useful insights about these considerations 410 can be found in [I-D.kline-mif-mpvd-api-reqs]. 412 3.4.1. DHCPv6 configuration association 414 When a host retrieves stateless configuration elements using DHCPv6 415 (e.g., DNS recursive resolvers or DNS domain search lists [RFC3646]), 416 they MUST be associated with all the explicit and implicit PvDs 417 received on the same interface and contained in a RA with the O-flag 418 set [RFC4861]. 420 When a host retrieves stateful assignments using DHCPv6, such 421 assignments MUST be associated with the received PvD which was 422 received with RAs with the M-flag set and including a matching PIO. 423 A PIO is considered to match a DHCPv6 assignment when the IPv6 prefix 424 from the PIO includes the assignment from DHCPv6. For example, if a 425 PvD's associated PIO defines the prefix 2001:db8:cafe::/64, a DHCPv6 426 IA_NA message that assigns the address 2001:db8:cafe::1234:4567 would 427 be considered to match. 429 In cases where an address would be assigned by DHCPv6 and no matching 430 PvD could be found, hosts MAY associate the assigned address with any 431 implicit PvD received on the same interface or to multiple of 432 implicit PvD received on the same interface. This is intended to 433 resolve backward compatibility issues with rare deployments choosing 434 to assign addresses with DHCPv6 while not sending any matching PIO. 436 3.4.2. DHCPv4 configuration association 438 Associating DHCPv4 [RFC2131] configuration elements with Explicit 439 PvDs allows hosts to treat a set of IPv4 and IPv6 configurations as a 440 single PvD with shared properties. For example, consider a router 441 that provides two different uplinks. One could be a broadband 442 network that has data rate and streaming properties described in PvD 443 additional information and that provides both IPv4 and IPv6 network 444 access. The other could be a cellular network that provides only 445 IPv6 network access, and uses NAT64 [RFC6146]. The broadband network 446 can be represented by an Explicit PvD that points to the additional 447 information, and also marks association with DHCPv4 information. The 448 cellular network can be represented by a different Explicit PvD that 449 is not associated with DHCPv4. 451 When a PvD-aware host retrieves configuration elements from DHCPv4, 452 the information is associated either with a single Explicit PvD on 453 that interface, or else with all Implicit PvDs on the same interface. 455 An Explicit PvD indicates its association with DHCPv4 information by 456 setting the L-flag in the PvD RA Option. If there is exactly one 457 Explicit PvD that sets this flag, hosts MUST associate the DHCPv4 458 information with that PvD. Multiple Explicit PvDs on the same 459 interface marking this flag is a misconfiguration, and hosts SHOULD 460 NOT associate the DHCPv4 information with any Explicit PvD in this 461 case. 463 If no single Explicit PvD claims association with DHCPv4, the 464 configuration elements coming from DHCPv4 MUST be associated with the 465 all Implicit PvDs identified by the interface on which the DHCPv4 466 transaction happened. This maintains existing host behavior. 468 3.4.3. Connection Sharing by the Host 470 The situation when a host shares connectivity from an upstream 471 interface (e.g. cellular) to a downstream interface (e.g. Wi-Fi) is 472 known as 'tethering'. Techniques such as ND-proxy [RFC4389], 64share 473 [RFC7278] or prefix delegation (e.g. using DHCPv6-PD [RFC8415]) may 474 be used for that purpose. 476 Whenever the RAs received from the upstream interface contain a PVD 477 RA option, hosts that are sharing connectivity SHOULD include a PVD 478 option within the RAs sent downstream with: 480 o The same PVD-ID FQDN 482 o The same H-bit, Delay and Sequence Number values 484 o The L bit set whenever the host is sharing IPv4 connectivity 485 received from the same upstream interface 487 o The bits from the Reserved field set to 0 489 The values of the R-bit, Router Advertisement message header and 490 Options field depend on whether the connectivity should be shared 491 only with PvD-aware hosts or not (see Section 3.2). In particular, 492 all options received within the upstream PvD Option and included in 493 the downstream RA SHOULD be included in the downstream PvD Option. 495 3.4.4. Usage of DNS Servers 497 PvD-aware hosts can be provisioned with recursive DNS servers via RA 498 options passed within an Explicit PvD, via RA options associated with 499 an Implicit PvD, via DHCPv6 or DHCPv4, or from some other 500 provisioning mechanism that creates an Implicit PvD (such as a VPN). 501 In all of these cases, the DNS server addresses SHOULD be associated 502 with the corresponding PvD. Specifically, queries sent to a 503 configured recursive DNS server SHOULD be sent from a local IP 504 address that was provisioned by the PvD via RA or DHCP. Answers 505 received from the DNS server SHOULD only be used on the same PvD. 507 PvD-aware applications will be able to select which PvD(s) to use for 508 DNS resolution and connections, which allows them to effectively use 509 multiple Explicit PvDs. In order to support non-PvD-aware 510 applications, however, PvD-aware hosts SHOULD ensure that non-PvD- 511 aware name resolution APIs like "getaddrinfo" only use resolvers from 512 a single PvD for each query. More discussion is provided in 513 Section 5.2.1 of [RFC7556]. 515 Maintaining the correct usage of DNS within PvDs avoids various 516 practical errors, such as: 518 o A PvD associated with a VPN or otherwise private network may 519 provide DNS answers that contain addresses inaccessible over 520 another PvD. 522 o A PvD that uses a NAT64 [RFC6146] and DNS64 [RFC6147] will 523 synthesize IPv6 addresses in DNS answers that are not globally 524 routable, and would be invalid on other PvDs. Conversely, an IPv4 525 address resolved via DNS on another PvD cannot be directly used on 526 a NAT64 network. 528 4. Provisioning Domain Additional Information 530 Additional information about the network characteristics can be 531 retrieved based on the PvD ID. This set of information is called PvD 532 Additional Information, and is encoded as a JSON object [RFC8259]. 533 This JSON object is restricted to the restricted profile of I-JSON, 534 as defined in [RFC7493]. 536 The purpose of this JSON object is to provide additional information 537 to applications on a client host about the connectivity that is 538 provided using a given interface and source address. It typically 539 includes data that would be considered too large, or not critical 540 enough, to be provided within an RA option. The information 541 contained in this object MAY be used by the operating system, network 542 libraries, applications, or users, in order to decide which set of 543 PvDs should be used for which connection, as described in 544 Section 3.4. 546 The additional information related to a PvD is specifically intended 547 to be optional, and is targeted at optimizing or informing the 548 behavior of user-facing hosts. This information can be extended to 549 provide hints for host system behavior (such as captive portal or 550 walled-garden PvD detection) or application behavior (describing 551 application-specific services offered on a given PvD). This content 552 may not be appropriate for light-weight Internet of Things (IoT) 553 devices. IoT devices might need only a subset of the information, 554 and would in some cases prefer a smaller representation like CBOR 555 ([RFC7049]). Delivering a reduced version of the PvD Additional 556 Information designed for such devices is not defined in this 557 document. 559 4.1. Retrieving the PvD Additional Information 561 When the H-flag of the PvD Option is set, hosts MAY attempt to 562 retrieve the PvD Additional Information associated with a given PvD 563 by performing an HTTP over TLS [RFC2818] GET query to https:///.well-known/pvd [RFC8615]. Inversely, hosts MUST NOT do so 565 whenever the H-flag is not set. 567 HTTP requests and responses for PvD additional information use the 568 "application/pvd+json" media type (see Section 8). Clients SHOULD 569 include this media type as an Accept header in their GET requests, 570 and servers MUST mark this media type as their Content-Type header in 571 responses. 573 Note that the DNS name resolution of the PvD ID, the PKI (Public Key 574 Infrastructure) checks as well as the actual query MUST be performed 575 using the considered PvD. In other words, the name resolution, PKI 576 checks, source address selection, as well as the next-hop router 577 selection MUST be performed while using exclusively the set of 578 configuration information attached with the PvD, as defined in 579 Section 3.4. In some cases, it may therefore be necessary to wait 580 for an address to be available for use (e.g., once the Duplicate 581 Address Detection or DHCPv6 processes are complete) before initiating 582 the HTTP over TLS query. If the host has a temporary address per 583 [RFC4941] in this PvD, then hosts SHOULD use a temporary address to 584 fetch the PvD Additional Information and SHOULD deprecate the used 585 temporary address and generate a new temporary address afterward. 587 If the HTTP status of the answer is greater than or equal to 400 the 588 host MUST abandon and consider that there is no additional PvD 589 information. If the HTTP status of the answer is between 300 and 590 399, inclusive, it MUST follow the redirection(s). If the HTTP 591 status of the answer is between 200 and 299, inclusive, the host MAY 592 get a file containing a single JSON object. 594 After retrieval of the PvD Additional Information, hosts MUST 595 remember the last Sequence Number value received in the RA including 596 the same PvD ID. Whenever a new RA for the same PvD is received with 597 a different Sequence Number value, or whenever the expiry date for 598 the additional information is reached, hosts MUST deprecate the 599 additional information and stop using it until a new JSON object is 600 retrieved. 602 Hosts retrieving a new PvD Additional Information object MUST check 603 for the presence and validity of the mandatory fields specified in 604 Section 4.3. A retrieved object including an expiration time that is 605 already past or missing a mandatory element MUST be ignored. 607 In order to avoid synchronized queries toward the server hosting the 608 PvD Additional Information when an object expires, object updates are 609 delayed by a randomized backoff time. 611 o When a host performs a JSON object update after it detected a 612 change in the PvD Option Sequence Number, it MUST add a delay 613 before sending the query. The target time for the delay is 614 calculated as a random time between zero and 2**(Delay * 2) 615 milliseconds, where 'Delay' corresponds to the 4-bit unsigned 616 integer in the last received PvD Option. 618 o When a host last retrieved a JSON object at time A that includes a 619 expiry time B using the "expires" key, and the host is configured 620 to keep the PvD information up to date, it MUST add some 621 randomness into its calculation of the time to fetch the update. 622 The target time for fetching the updated object is calculated as a 623 uniformly random time in the interval [(B-A)/2,B]. 625 In the example Figure 2, the delay field value is 5, this means that 626 host calculates its delay by choosing a random number between 0 and 627 2**(5 * 2) milliseconds, i.e., between 0 and 1024 milliseconds. 629 Since the 'Delay' value is directly within the PvD Option rather than 630 the object itself, an operator may perform a push-based update by 631 incrementing the Sequence value while changing the Delay value 632 depending on the criticality of the update and its PvD Additional 633 Information servers capacity. 635 The PvD Additional Information object includes a set of IPv6 prefixes 636 (under the key "prefixes") which MUST be checked against all the 637 Prefix Information Options advertised in the RA. If any of the 638 prefixes included in any associated PIO is not covered by at least 639 one of the listed prefixes, the associated PvD information MUST be 640 considered to be a misconfiguration, and MUST NOT be used by the 641 host. See Section 4.4 for more discussion on handling such 642 misconfigurations. 644 4.2. Operational Consideration to Providing the PvD Additional 645 Information 647 Whenever the H-flag is set in the PvD Option, a valid PvD Additional 648 Information object MUST be made available to all hosts receiving the 649 RA by the network operator. In particular, when a captive portal is 650 present, hosts MUST still be allowed to perform DNS, PKI and HTTP 651 over TLS operations related to the retrieval of the object, even 652 before logging into the captive portal. 654 Routers SHOULD increment the PVD Option Sequence Number by one 655 whenever a new PvD Additional Information object is available and 656 should be retrieved by hosts. If the value exceeds what can be 657 stored in the Sequence Number field, it SHOULD wrap back to zero. 659 The server providing the JSON files SHOULD also check whether the 660 client address is part of the prefixes listed into the additional 661 information and SHOULD return a 403 response code if there is no 662 match. 664 4.3. PvD Additional Information Format 666 The PvD Additional Information is a JSON object. 668 The following table presents the mandatory keys which MUST be 669 included in the object: 671 +------------+-----------------+-----------+------------------------+ 672 | JSON key | Description | Type | Example | 673 +------------+-----------------+-----------+------------------------+ 674 | identifier | PvD ID FQDN | String | "pvd.example.com." | 675 | | | | | 676 | expires | Date after | [RFC3339] | "2017-07-23T06:00:00Z" | 677 | | which this | Date | | 678 | | object is no | | | 679 | | longer valid | | | 680 | | | | | 681 | prefixes | Array of IPv6 | Array of | ["2001:db8:1::/48", | 682 | | prefixes valid | strings | "2001:db8:4::/48"] | 683 | | for this PvD | | | 684 +------------+-----------------+-----------+------------------------+ 686 A retrieved object which does not include all three of these keys at 687 the root of the JSON object MUST be ignored. All three keys need to 688 be validated, otherwise the object MUST be ignored. The value stored 689 for "identifier" MUST be matched against the PvD ID FQDN presented in 690 the PvD RA option using the comparison mechanism described in 691 Section 3.4. The value stored for "expires" MUST be a valid date in 692 the future. If the PIO of the received RA is not covered by at least 693 one of the "prefixes" key, the retrieved object SHOULD be ignored. 695 The following table presents some optional keys which MAY be included 696 in the object. 698 +------------+----------------------+----------+--------------------+ 699 | JSON key | Description | Type | Example | 700 +------------+----------------------+----------+--------------------+ 701 | dnsZones | DNS zones searchable | Array of | ["example.com", | 702 | | and accessible | strings | "sub.example.com"] | 703 | | | | | 704 | noInternet | No Internet, set | Boolean | true | 705 | | when the PvD is | | | 706 | | restricted. | | | 707 +------------+----------------------+----------+--------------------+ 709 It is worth noting that the JSON format allows for extensions. 710 Whenever an unknown key is encountered, it MUST be ignored along with 711 its associated elements. 713 Private-use or experimental keys MAY be used in the JSON dictionary. 714 In order to avoid such keys colliding with IANA registry keys, 715 implementers or vendors defining private-use or experimental keys 716 MUST create sub-dictionaries, where the sub-dictionary is added into 717 the top-level JSON dictionary with a key of the format "vendor-*" 718 where the "*" is replaced by the implementer's or vendor's 719 identifier. For example, keys specific to the FooBar organization 720 could use "vendor-foobar". Upon receiving such a sub-dictionary, 721 host MUST ignore this sub-dictionary if it is unknown. When the 722 vendor or implementer is part of an IANA URN namespace [URN], the URN 723 namespace SHOULD be used rather than the "vendor-*" format. 725 4.3.1. Example 727 The following two examples show how the JSON keys defined in this 728 document can be used: 730 { 731 "identifier": "cafe.example.com", 732 "expires": "2017-07-23T06:00:00Z", 733 "prefixes": ["2001:db8:1::/48", "2001:db8:4::/48"], 734 } 736 { 737 "identifier": "company.foo.example.com", 738 "expires": "2017-07-23T06:00:00Z", 739 "prefixes": ["2001:db8:1::/48", "2001:db8:4::/48"], 740 "vendor-foo": 741 { 742 "private-key": "private-value", 743 }, 744 } 746 4.4. Detecting misconfiguration and misuse 748 When a host retrieves the PvD Additional Information, it MUST verify 749 that the TLS server certificate is valid for the performed request 750 (e.g., that the Subject Name is equal to the PvD ID expressed as an 751 FQDN). This authentication creates a secure binding between the 752 information provided by the trusted Router Advertisement, and the 753 HTTPS server. However, this does not mean the Advertising Router and 754 the PvD server belong to the same entity. 756 Hosts MUST verify that all prefixes in all the RA PIOs are covered by 757 a prefix from the PvD Additional Information. An adversarial router 758 attempting to spoof the definition of an Explicit PvD, without the 759 ability to modify the PvD Additional Information, would need to 760 perform NAT66 in order to circumvent this check. Thus, this check 761 cannot prevent all spoofing, but it can detect misconfiguration or 762 mismatched routers that are not adding a NAT. 764 If NAT66 is being added in order to spoof PvD ownership, the HTTPS 765 server for additional information can detect this misconfiguration. 766 The HTTPS server SHOULD validate the source addresses of incoming 767 connections (see Section 4.1). This check gives reasonable assurance 768 that neither NPTv6 [RFC6296] nor NAT66 were used and restricts the 769 information to the valid network users. If the PvD does not 770 provision IPv4 (it does not include the 'L' bit in the RA), the 771 server cannot validate the source addresses of connections using 772 IPv4. Thus, the PvD ID FQDN for such PvDs SHOULD NOT have a DNS A 773 record. 775 5. Operational Considerations 777 This section describes some example use cases of PvD. For the sake 778 of simplicity, the RA messages will not be described in the usual 779 ASCII art but rather in an indented list. 781 5.1. Exposing Extra RA Options to PvD-Aware Hosts 783 In this example, there is one RA message sent by the router. This 784 message contains some options applicable to all hosts on the network, 785 and also a PvD Option that also contains other options only visible 786 to PvD-aware hosts. 788 o RA Header: router lifetime = 6000 790 o Prefix Information Option: length = 4, prefix = 2001:db8:cafe::/64 792 o PvD Option header: length = 3 + 5 + 4 , PvD ID FQDN = 793 example.org., R-flag = 0 (actual length of the header with padding 794 24 bytes = 3 * 8 bytes) 796 * Recursive DNS Server: length = 5, addresses = 797 [2001:db8:cafe::53, 2001:db8:f00d::53] 799 * Prefix Information Option: length = 4, prefix = 800 2001:db8:f00d::/64 802 Note that a PvD-aware host will receive two different prefixes, 803 2001:db8:cafe::/64 and 2001:db8:f00d::/64, both associated with the 804 same PvD (identified by "example.org."). A non-PvD-aware host will 805 only receive one prefix, 2001:db8:cafe::/64. 807 5.2. Different RAs for PvD-Aware and Non-PvD-Aware Hosts 809 It is expected that for some years, networks will have a mixed 810 environment of PvD-aware hosts and non-PvD-aware hosts. If there is 811 a need to give specific information to PvD-aware hosts only, then it 812 is RECOMMENDED to send two RA messages, one for each class of hosts. 813 If two RA messages are sent for this reason, they MUST be sent from 814 two different link-local source addresses (Section 3.2). For 815 example, here is the RA sent for non-PvD-aware hosts: 817 o RA Header: router lifetime = 6000 (non-PvD-aware hosts will use 818 this router as a default router) 820 o Prefix Information Option: length = 4, prefix = 2001:db8:cafe::/64 822 o Recursive DNS Server Option: length = 3, addresses= 823 [2001:db8:cafe::53] 825 o PvD Option header: length = 3 + 2, PvD ID FQDN = foo.example.org., 826 R-flag = 1 (actual length of the header 24 bytes = 3 * 8 bytes) 828 * RA Header: router lifetime = 0 (PvD-aware hosts will not use 829 this router as a default router), implicit length = 2 831 And here is the RA sent for PvD-aware hosts: 833 o RA Header: router lifetime = 0 (non-PvD-aware hosts will not use 834 this router as a default router) 836 o PvD Option header: length = 3 + 2 + 4 + 3, PvD ID FQDN = 837 bar.example.org., R-flag = 1 (actual length of the header 24 bytes 838 = 3 * 8 bytes) 840 * RA Header: router lifetime = 1600 (PvD-aware hosts will use 841 this router as a default router), implicit length = 2 843 * Prefix Information Option: length = 4, prefix = 844 2001:db8:f00d::/64 846 * Recursive DNS Server Option: length = 3, addresses = 847 [2001:db8:f00d::53] 849 In the above example, non-PvD-aware hosts will only use the first RA 850 sent from their default router and using the 2001:db8:cafe::/64 851 prefix. PvD-aware hosts will autonomously configure addresses from 852 both PIOs, but will only use the source address in 2001:db8:f00d::/64 853 to communicate past the first hop router since only the router 854 sending the second RA will be used as default router; similarly, they 855 will use the DNS server 2001:db8:f00d::53 when communicating with 856 this address. 858 5.3. Enabling Multi-homing for PvD-Aware Hosts 860 In this example, the goal is to have one prefix from one RA be usable 861 by both non-PvD-aware and PvD-aware hosts; and to have another prefix 862 usable only by PvD-aware hosts. This allows PvD-aware hosts to be 863 able to effectively multi-home on the network. 865 The first RA is usable by all hosts. The only difference for PvD- 866 aware hosts is that they can explicitly identify the PvD ID 867 associated with the RA. PvD-aware hosts will also use this prefix to 868 communicate with non-PvD-aware hosts on the same network. 870 o RA Header: router lifetime = 6000 (non-PvD-aware hosts will use 871 this router as a default router) 873 o Prefix Information Option: length = 4, prefix = 2001:db8:cafe::/64 875 o Recursive DNS Server Option: length = 3, addresses= 876 [2001:db8:cafe::53] 878 o PvD Option header: length = 3, PvD ID FQDN = foo.example.org., 879 R-flag = 0 (actual length of the header 24 bytes = 3 * 8 bytes) 881 The second RA contains a prefix usable only by PvD-aware hosts. Non- 882 PvD-aware hosts will ignore this RA; hence, the only PvD-aware hosts 883 will be multi-homed. 885 o RA Header: router lifetime = 0 (non-PvD-aware hosts will not use 886 this router as a default router) 888 o PvD Option header: length = 3 + 2 + 4 + 3, PvD ID FQDN = 889 bar.example.org., R-flag = 1 (actual length of the header 24 bytes 890 = 3 * 8 bytes) 892 * RA Header: router lifetime = 1600 (PvD-aware hosts will use 893 this router as a default router), implicit length = 2 895 * Prefix Information Option: length = 4, prefix = 896 2001:db8:f00d::/64 898 * Recursive DNS Server Option: length = 3, addresses = 899 [2001:db8:f00d::53] 901 Note: the above examples assume that the router has received its PvD 902 IDs from upstream routers or via some other configuration mechanism. 903 Another document could define ways for the router to generate its own 904 PvD IDs to allow the above scenario in the absence of PvD ID 905 provisioning. 907 6. Security Considerations 909 Although some solutions such as IPsec or SeND [RFC3971] can be used 910 in order to secure the IPv6 Neighbor Discovery Protocol, in practice 911 actual deployments largely rely on link layer or physical layer 912 security mechanisms (e.g. 802.1x [IEEE8021X]) in conjunction with RA 913 Guard [RFC6105]. 915 This specification does not improve the Neighbor Discovery Protocol 916 security model, but extends the purely link-local trust relationship 917 between the host and the default routers with HTTP over TLS 918 communications which servers are authenticated as rightful owners of 919 the FQDN received within the trusted PvD ID RA option. 921 It must be noted that Section 4.4 of this document only provides 922 reasonable assurance against misconfiguration but does not prevent an 923 hostile network access provider to advertise wrong information that 924 could lead applications or hosts to select a hostile PvD. 926 Users cannot be assumed to be able to meaningfully differentiate 927 between "safe" and "unsafe" networks. This is a known attack surface 928 that is present whether or not PvDs are in use, and hence cannot be 929 addressed by this document. However, a host that correctly 930 implements the multiple PvD architecture ([RFC7556]) using the 931 mechanism described in this document will be less susceptible to such 932 attacks than a host that does not by being able to check for the 933 various misconfigurations described in this document. 935 7. Privacy Considerations 937 Retrieval of the PvD Additional Information over HTTPS requires early 938 communications between the connecting host and a server which may be 939 located further than the first hop router. Although this server is 940 likely to be located within the same administrative domain as the 941 default router, this property can't be ensured. Therefore, hosts 942 willing to retrieve the PvD Additional Information before using it 943 without leaking identity information, SHOULD make use of an IPv6 944 Privacy Address and SHOULD NOT include any privacy sensitive data, 945 such as User Agent header or HTTP cookie, while performing the HTTP 946 over TLS query. 948 From a privacy perspective, retrieving the PvD Additional Information 949 is not different from establishing a first connection to a remote 950 server, or even performing a single DNS lookup. For example, most 951 operating systems already perform early queries to well known web 952 sites, such as http://captive.example.com/hotspot-detect.html, in 953 order to detect the presence of a captive portal. 955 There may be some cases where hosts, for privacy reasons, should 956 refrain from accessing servers that are located outside a certain 957 network boundary. In practice, this could be implemented as a 958 whitelist of 'trusted' FQDNs and/or IP prefixes that the host is 959 allowed to communicate with. In such scenarios, the host SHOULD 960 check that the provided PvD ID, as well as the IP address that it 961 resolves into, are part of the allowed whitelist. 963 8. IANA Considerations 965 Upon publication of this document, IANA is asked to remove the 966 'reclaimable' tag off the value 21 for the PvD Option (from the IPv6 967 Neighbor Discovery Option Formats registry). 969 8.1. New entry in the Well-Known URIs Registry 971 IANA is asked to add a new entry in the well-known-uris registry with 972 the following information: 974 URI suffix: 'pvd' 976 Change controller: IETF 978 Specification document: this document 980 Status: permanent 982 Related information: N/A 984 8.2. Additional Information PvD Keys Registry 986 IANA is asked to create and maintain a new registry called 987 "Additional Information PvD Keys", which will reserve JSON keys for 988 use in PvD additional information. The initial contents of this 989 registry are given in Section 4.3. 991 New assignments for Additional Information PvD Keys Registry will be 992 administered by IANA through Expert Review [RFC8126]. 994 8.3. PvD Option Flags Registry 996 IANA is also asked to create and maintain a new registry entitled 997 "PvD Option Flags" reserving bit positions from 0 to 15 to be used in 998 the PvD Option bitmask. Bit position 0, 1 and 2 are reserved by this 999 document (as specified in Figure 1). Future assignments require 1000 Standards Action [RFC8126], via a Standards Track RFC document. 1002 8.4. PvD JSON Media Type Registration 1004 This document registers the media type for PvD JSON text, 1005 "application/pvd+json". 1007 Type Name: application 1009 Subtype Name: pvd+json 1011 Required parameters: None 1013 Optional parameters: None 1015 Encoding considerations: Encoding considerations are identical to 1016 those specified for the "application/json" media type. 1018 Security considerations: See Section 6. 1020 Interoperability considerations: This document specifies format of 1021 conforming messages and the interpretation thereof. 1023 Published specification: This document 1025 Applications that use this media type: This media type is intended to 1026 be used by network advertising additional Provisioning Domain 1027 information, and clients looking up such information. 1029 Additional information: None 1031 Person and email address to contact for further information: See 1032 Authors' Addresses section 1034 Intended usage: COMMON 1036 Restrictions on usage: None 1038 Author: IETF 1040 Change controller: IETF 1042 9. Acknowledgments 1044 Many thanks to M. Stenberg and S. Barth for their earlier work: 1045 [I-D.stenberg-mif-mpvd-dns], as well as to Basile Bruneau who was 1046 author of an early version of this document. 1048 Thanks also to Marcus Keane, Mikael Abrahamsson, Ray Bellis, Zhen 1049 Cao, Tim Chown, Lorenzo Colitti, Michael Di Bartolomeo, Ian Farrer, 1050 Phillip Hallam-Baker, Bob Hinden, Tatuya Jinmei, Erik Kline, Ted 1051 Lemon, Paul Hoffman, Dave Thaler, Suresh Krishnan, Gorry Fairhurst, 1052 Jen Lenkova, Veronika McKillop, Mark Townsley and James Woodyatt for 1053 useful and interesting discussions and reviews. 1055 Finally, special thanks to Thierry Danis for his valuable inputs and 1056 implementation efforts, Tom Jones for his integration effort into the 1057 NEAT project and Rigil Salim for his implementation work. 1059 10. References 1061 10.1. Normative References 1063 [RFC1035] Mockapetris, P., "Domain names - implementation and 1064 specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, 1065 November 1987, . 1067 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1068 Requirement Levels", BCP 14, RFC 2119, 1069 DOI 10.17487/RFC2119, March 1997, 1070 . 1072 [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", 1073 RFC 2131, DOI 10.17487/RFC2131, March 1997, 1074 . 1076 [RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet: 1077 Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002, 1078 . 1080 [RFC3646] Droms, R., Ed., "DNS Configuration options for Dynamic 1081 Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3646, 1082 DOI 10.17487/RFC3646, December 2003, 1083 . 1085 [RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and 1086 More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191, 1087 November 2005, . 1089 [RFC4343] Eastlake 3rd, D., "Domain Name System (DNS) Case 1090 Insensitivity Clarification", RFC 4343, 1091 DOI 10.17487/RFC4343, January 2006, 1092 . 1094 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 1095 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 1096 DOI 10.17487/RFC4861, September 2007, 1097 . 1099 [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy 1100 Extensions for Stateless Address Autoconfiguration in 1101 IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007, 1102 . 1104 [RFC6724] Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown, 1105 "Default Address Selection for Internet Protocol Version 6 1106 (IPv6)", RFC 6724, DOI 10.17487/RFC6724, September 2012, 1107 . 1109 [RFC7493] Bray, T., Ed., "The I-JSON Message Format", RFC 7493, 1110 DOI 10.17487/RFC7493, March 2015, 1111 . 1113 [RFC8028] Baker, F. and B. Carpenter, "First-Hop Router Selection by 1114 Hosts in a Multi-Prefix Network", RFC 8028, 1115 DOI 10.17487/RFC8028, November 2016, 1116 . 1118 [RFC8106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli, 1119 "IPv6 Router Advertisement Options for DNS Configuration", 1120 RFC 8106, DOI 10.17487/RFC8106, March 2017, 1121 . 1123 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 1124 Writing an IANA Considerations Section in RFCs", BCP 26, 1125 RFC 8126, DOI 10.17487/RFC8126, June 2017, 1126 . 1128 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1129 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1130 May 2017, . 1132 [RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data 1133 Interchange Format", STD 90, RFC 8259, 1134 DOI 10.17487/RFC8259, December 2017, 1135 . 1137 [RFC8615] Nottingham, M., "Well-Known Uniform Resource Identifiers 1138 (URIs)", RFC 8615, DOI 10.17487/RFC8615, May 2019, 1139 . 1141 10.2. Informative References 1143 [I-D.kline-mif-mpvd-api-reqs] 1144 Kline, E., "Multiple Provisioning Domains API 1145 Requirements", draft-kline-mif-mpvd-api-reqs-00 (work in 1146 progress), November 2015. 1148 [I-D.stenberg-mif-mpvd-dns] 1149 Stenberg, M. and S. Barth, "Multiple Provisioning Domains 1150 using Domain Name System", draft-stenberg-mif-mpvd-dns-00 1151 (work in progress), October 2015. 1153 [IEEE8021X] 1154 "IEEE Standards for Local and Metropolitan Area Networks, 1155 Port-based Network Access Control, IEEE Std", n.d.. 1157 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 1158 DOI 10.17487/RFC2818, May 2000, 1159 . 1161 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 1162 "SEcure Neighbor Discovery (SEND)", RFC 3971, 1163 DOI 10.17487/RFC3971, March 2005, 1164 . 1166 [RFC4389] Thaler, D., Talwar, M., and C. Patel, "Neighbor Discovery 1167 Proxies (ND Proxy)", RFC 4389, DOI 10.17487/RFC4389, April 1168 2006, . 1170 [RFC6105] Levy-Abegnoli, E., Van de Velde, G., Popoviciu, C., and J. 1171 Mohacsi, "IPv6 Router Advertisement Guard", RFC 6105, 1172 DOI 10.17487/RFC6105, February 2011, 1173 . 1175 [RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful 1176 NAT64: Network Address and Protocol Translation from IPv6 1177 Clients to IPv4 Servers", RFC 6146, DOI 10.17487/RFC6146, 1178 April 2011, . 1180 [RFC6147] Bagnulo, M., Sullivan, A., Matthews, P., and I. van 1181 Beijnum, "DNS64: DNS Extensions for Network Address 1182 Translation from IPv6 Clients to IPv4 Servers", RFC 6147, 1183 DOI 10.17487/RFC6147, April 2011, 1184 . 1186 [RFC6296] Wasserman, M. and F. Baker, "IPv6-to-IPv6 Network Prefix 1187 Translation", RFC 6296, DOI 10.17487/RFC6296, June 2011, 1188 . 1190 [RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object 1191 Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049, 1192 October 2013, . 1194 [RFC7278] Byrne, C., Drown, D., and A. Vizdal, "Extending an IPv6 1195 /64 Prefix from a Third Generation Partnership Project 1196 (3GPP) Mobile Interface to a LAN Link", RFC 7278, 1197 DOI 10.17487/RFC7278, June 2014, 1198 . 1200 [RFC7556] Anipko, D., Ed., "Multiple Provisioning Domain 1201 Architecture", RFC 7556, DOI 10.17487/RFC7556, June 2015, 1202 . 1204 [RFC8415] Mrugalski, T., Siodelski, M., Volz, B., Yourtchenko, A., 1205 Richardson, M., Jiang, S., Lemon, T., and T. Winters, 1206 "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", 1207 RFC 8415, DOI 10.17487/RFC8415, November 2018, 1208 . 1210 [URN] "URN Namespaces", n.d.. 1212 Authors' Addresses 1214 Pierre Pfister 1215 Cisco 1216 11 Rue Camille Desmoulins 1217 Issy-les-Moulineaux 92130 1218 France 1220 Email: ppfister@cisco.com 1222 Eric Vyncke 1223 Cisco 1224 De Kleetlaan, 6 1225 Diegem 1831 1226 Belgium 1228 Email: evyncke@cisco.com 1230 Tommy Pauly 1231 Apple Inc. 1232 One Apple Park Way 1233 Cupertino, California 95014 1234 United States of America 1236 Email: tpauly@apple.com 1237 David Schinazi 1238 Google LLC 1239 1600 Amphitheatre Parkway 1240 Mountain View, California 94043 1241 United States of America 1243 Email: dschinazi.ietf@gmail.com 1245 Wenqin Shao 1246 Cisco 1247 11 Rue Camille Desmoulins 1248 Issy-les-Moulineaux 92130 1249 France 1251 Email: wenshao@cisco.com