idnits 2.17.1 draft-ietf-intarea-provisioning-domains-10.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 (January 06, 2020) is 1571 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: July 9, 2020 T. Pauly 6 Apple Inc. 7 D. Schinazi 8 Google LLC 9 W. Shao 10 Cisco 11 January 06, 2020 13 Discovering Provisioning Domain Names and Data 14 draft-ietf-intarea-provisioning-domains-10 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 July 9, 2020. 48 Copyright Notice 50 Copyright (c) 2020 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 . . . . . . . . . . 11 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 . . . . . . . . . 13 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 5.4. Providing Additional Information to PvD-Aware Hosts . . . 21 90 6. Security Considerations . . . . . . . . . . . . . . . . . . . 22 91 7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 22 92 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23 93 8.1. New entry in the Well-Known URIs Registry . . . . . . . . 23 94 8.2. Additional Information PvD Keys Registry . . . . . . . . 24 95 8.3. PvD Option Flags Registry . . . . . . . . . . . . . . . . 24 96 8.4. PvD JSON Media Type Registration . . . . . . . . . . . . 24 97 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 25 98 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 26 99 10.1. Normative References . . . . . . . . . . . . . . . . . . 26 100 10.2. Informative References . . . . . . . . . . . . . . . . . 27 101 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29 103 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 information 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 derived from it. The PVD ID Router Advertisement option may also 141 contain a set of other RA options, along with an optional inner 142 Router Advertisement message header. These options and optional 143 inner header are only visible to 'PvD-aware' hosts, allowing such 144 hosts to have a specialized view of the network configuration. 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) that identifies the network operator. 205 Network operators MUST use names that they own or manage to avoid 206 naming conflicts. The same PvD ID MAY be used in several access 207 networks when they ultimately provide identical services (e.g., in 208 all home networks subscribed to the same service); else, the PvD ID 209 MUST be different to follow Section 2.4 of [RFC7556]. 211 3.1. PvD ID Option for Router Advertisements 213 This document introduces a Router Advertisement (RA) option called 214 the PvD Option. It is used to convey the FQDN identifying a given 215 PvD (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 PvD is associated 254 with IPv4 information assigned 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]). The usage of the inner message header is 260 described in Section 3.4. 262 Reserved: (13 bits) Reserved for later use. It MUST be set to zero 263 by the sender and ignored by the receiver. 265 Delay: (4 bits) Unsigned integer used to delay HTTP GET queries from 266 hosts by a randomized backoff (see Section 4.1). 268 Sequence Number: (16 bits) Sequence number for the PvD Additional 269 Information, as described in Section 4. 271 PvD ID FQDN: The FQDN used as PvD ID encoded in DNS format, as 272 described in Section 3.1 of [RFC1035]. Domain name compression 273 described in Section 4.1.4 of [RFC1035] MUST NOT be used. 275 Padding: Zero or more padding octets to the next 8 octet boundary 276 (see Section 4.6 of [RFC4861]). It MUST be set to zero by the 277 sender, and ignored by the receiver. 279 RA message header: (16 octets) When the R-flag is set, a full Router 280 Advertisement message header as specified in [RFC4861]. The 281 sender MUST set the 'Type' to 134, the value for "Router 282 Advertisement", and set the 'Code' to 0. Receivers MUST ignore 283 both of these fields. The 'Checksum' MUST be set to 0 by the 284 sender; non-zero checksums MUST be ignored by the receiver without 285 causing the processing of the message to fail. All other fields 286 are to be set and parsed as specified in [RFC4861] or any updating 287 documents. 289 Options: Zero or more RA options that would otherwise be valid as 290 part of the Router Advertisement main body, but are instead 291 included in the PvD Option so as to be ignored by hosts that are 292 not PvD-aware. 294 Figure 2 shows an example of a PvD Option with "example.org" as the 295 PvD ID FQDN and including both a Recursive DNS Server (RDNSS) option 296 and a prefix information option. It has a Sequence Number of 123, 297 and indicates the presence of additional information that is expected 298 to be fetched with a delay factor of 5. 300 0 1 2 3 301 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 1 302 +---------------+-----------------------------------------------+ 303 | Type: 21 | Length: 12 |1|0|0| Reserved |Delay:5| 304 +---------------+-------------------------------+---------------+ 305 | Seq number: 123 | 7 | e | 306 +---------------+-----------------------------------------------+ 307 | x | a | m | p | 308 +---------------------------------------------------------------+ 309 | l | e | 3 | o | 310 +---------------------------------------------------------------+ 311 | r | g | 0 | 0 (padding) | 312 +---------------------------------------------------------------+ 313 | 0 (padding) | 0 (padding) | 0 (padding) | 0 (padding) | 314 +---------------+---------------+---------------+---------------+ 315 | RDNSS option (RFC 8106) length: 5 ... 316 ... ... 317 ... | 318 +---------------------------------------------------------------+ 319 | Prefix Information Option (RFC 4861) length: 4 ... 320 ... | 321 ... | 322 +---------------------------------------------------------------+ 324 Figure 2 326 3.2. Router Behavior 328 A router MAY send RAs containing one PvD Option, but MUST NOT include 329 more than one PvD Option in each RA. The PvD Option MUST NOT contain 330 further PvD Options. 332 The PvD Option MAY contain zero, one, or more RA options which would 333 otherwise be valid as part of the same RA. Such options are 334 processed by PvD-aware hosts, while ignored by other hosts as per 335 section 4.2 of [RFC4861]. 337 In order to provide multiple different PvDs, a router MUST send 338 multiple RAs. If more than one different Implicit PvD is advertised, 339 the RAs MUST be sent from different link-local source addresses. 340 Explicit PvDs MAY share link-local source addresses with an Implicit 341 PvD and any number of other Explicit PvDs. 343 In other words, different Explicit PvDs MAY be advertised with RAs 344 using the same link-local source address; but different Implicit 345 PvDs, advertised by different RAs, MUST use different link-local 346 addresses because these Implicit PvDs are identified by the source 347 addresses of the RAs. If a link-local address on the router is 348 changed, then any new RA will be interpreted as a different Implicit 349 PvD by PvD-aware hosts. 351 As specified in [RFC4861] and [RFC6980], when the set of options 352 causes the size of an advertisement to exceed the link MTU, multiple 353 router advertisements MUST be sent to avoid fragmentation, each 354 containing a subset of the options. In such cases, the PvD Option 355 header (i.e., all fields except the 'Options' field) MUST be repeated 356 in all the transmitted RAs. The options within the 'Options' field, 357 MAY be transmitted only once, included in one of the transmitted PvD 358 Options. 360 3.3. Non-PvD-aware Host Behavior 362 As the PvD Option has a new option code, non-PvD-aware hosts will 363 simply ignore the PvD Option and all the options it contains (see 364 section 4.2 of [RFC4861]. This ensures the backward compatibility 365 required in Section 3.3 of [RFC7556]. This behavior allows for a 366 mixed-mode network where a mix of PvD-aware and non-PvD-aware hosts 367 coexist. 369 3.4. PvD-aware Host Behavior 371 Hosts MUST associate received RAs and included configuration 372 information (e.g., Router Valid Lifetime, Prefix Information 373 [RFC4861], Recursive DNS Server [RFC8106], Routing Information 374 [RFC4191] options) with the Explicit PvD identified by the first PvD 375 Option present in the received RA, if any, or with the Implicit PvD 376 identified by the host interface and the source address of the 377 received RA otherwise. If an RA message header is present both 378 within the PvD Option and outside it, as indicated by the R-flag, the 379 header within the PvD Option takes precedence. 381 In case multiple PvD Options are found in a given RA, hosts MUST 382 ignore all but the first PvD Option. 384 If a host receives PvD Options flags that it does not recognize 385 (currently in the Reserved field), it MUST ignore these flags. 387 Similarly, hosts MUST associate all network configuration objects 388 (e.g., default routers, addresses, more specific routes, DNS 389 Recursive Resolvers) with the PvD associated with the RA which last 390 updated the object. For example, addresses that are generated using 391 a received Prefix Information option (PIO) are associated with the 392 PvD of the last received RA which included the given PIO. 394 PvD IDs MUST be compared in a case-insensitive manner as defined by 395 [RFC4343]. For example, "pvd.example.com." or "PvD.Example.coM." 396 would refer to the same PvD. 398 While resolving names, executing the default address selection 399 algorithm [RFC6724] or executing the default router selection 400 algorithm when forwarding packets ([RFC4861], [RFC4191] and 401 [RFC8028]), hosts and applications MAY consider only the 402 configuration associated with any non-empty subset of PvDs. 404 For example, a host MAY associate a given process with a specific 405 PvD, or a specific set of PvDs, while associating another process 406 with another PvD. A PvD-aware application might also be able to 407 select, on a per-connection basis, which PvDs should be used. In 408 particular, constrained devices such as small battery operated 409 devices (e.g., IoT), or devices with limited CPU or memory resources 410 may purposefully use a single PvD while ignoring some received RAs 411 containing different PvD IDs. 413 The way an application expresses its desire to use a given PvD, or a 414 set of PvDs, or the way this selection is enforced, is out of the 415 scope of this document. Useful insights about these considerations 416 can be found in [I-D.kline-mif-mpvd-api-reqs]. 418 3.4.1. DHCPv6 configuration association 420 When a host retrieves stateless configuration elements using DHCPv6 421 (e.g., DNS recursive resolvers or DNS domain search lists [RFC3646]), 422 they MUST be associated with all the explicit and implicit PvDs 423 received on the same interface and contained in a RA with the O-flag 424 set [RFC4861]. 426 When a host retrieves stateful assignments using DHCPv6, such 427 assignments MUST be associated with the received PvD which was 428 received with RAs with the M-flag set and including a matching PIO. 429 A PIO is considered to match a DHCPv6 assignment when the IPv6 prefix 430 from the PIO includes the assignment from DHCPv6. For example, if a 431 PvD's associated PIO defines the prefix 2001:db8:cafe::/64, a DHCPv6 432 IA_NA message that assigns the address 2001:db8:cafe::1234:4567 would 433 be considered to match. 435 In cases where an address would be assigned by DHCPv6 and no matching 436 PvD could be found, hosts MAY associate the assigned address with any 437 implicit PvD received on the same interface or to multiple of 438 implicit PvD received on the same interface. This is intended to 439 resolve backward compatibility issues with rare deployments choosing 440 to assign addresses with DHCPv6 while not sending any matching PIO. 442 3.4.2. DHCPv4 configuration association 444 Associating DHCPv4 [RFC2131] configuration elements with Explicit 445 PvDs allows hosts to treat a set of IPv4 and IPv6 configurations as a 446 single PvD with shared properties. For example, consider a router 447 that provides two different uplinks. One could be a broadband 448 network that has data rate and streaming properties described in PvD 449 additional information and that provides both IPv4 and IPv6 network 450 access. The other could be a cellular network that provides only 451 IPv6 network access, and uses NAT64 [RFC6146]. The broadband network 452 can be represented by an Explicit PvD that points to the additional 453 information, and also marks association with DHCPv4 information. The 454 cellular network can be represented by a different Explicit PvD that 455 is not associated with DHCPv4. 457 When a PvD-aware host retrieves configuration elements from DHCPv4, 458 the information is associated either with a single Explicit PvD on 459 that interface, or else with all Implicit PvDs on the same interface. 461 An Explicit PvD indicates its association with DHCPv4 information by 462 setting the L-flag in the PvD RA Option. If there is exactly one 463 Explicit PvD that sets this flag, hosts MUST associate the DHCPv4 464 information with that PvD. Multiple Explicit PvDs on the same 465 interface marking this flag is a misconfiguration, and hosts SHOULD 466 NOT associate the DHCPv4 information with any Explicit PvD in this 467 case. 469 If no single Explicit PvD claims association with DHCPv4, the 470 configuration elements coming from DHCPv4 MUST be associated with all 471 Implicit PvDs identified by the interface on which the DHCPv4 472 transaction happened. This maintains existing host behavior. 474 3.4.3. Connection Sharing by the Host 476 The situation when a host shares connectivity from an upstream 477 interface (e.g., cellular) to a downstream interface (e.g., Wi-Fi) is 478 known as 'tethering'. Techniques such as ND-proxy [RFC4389], 64share 479 [RFC7278] or prefix delegation (e.g., using DHCPv6-PD [RFC8415]) may 480 be used for that purpose. 482 Whenever the RAs received from the upstream interface contain a PVD 483 RA option, hosts that are sharing connectivity SHOULD include a PVD 484 option within the RAs sent downstream with: 486 o The same PVD-ID FQDN 488 o The same H-flag, Delay and Sequence Number values 489 o The L bit set whenever the host is sharing IPv4 connectivity 490 received from the same upstream interface 492 o The bits from the Reserved field set to 0 494 The values of the R-flag, Router Advertisement message header and 495 Options field depend on whether the connectivity should be shared 496 only with PvD-aware hosts or not (see Section 3.2). In particular, 497 all options received within the upstream PvD Option and included in 498 the downstream RA SHOULD be included in the downstream PvD Option. 500 3.4.4. Usage of DNS Servers 502 PvD-aware hosts can be provisioned with recursive DNS servers via RA 503 options passed within an Explicit PvD, via RA options associated with 504 an Implicit PvD, via DHCPv6 or DHCPv4, or from some other 505 provisioning mechanism that creates an Implicit PvD (such as a VPN). 506 In all of these cases, the recursive DNS server addresses SHOULD be 507 associated with the corresponding PvD. Specifically, queries sent to 508 a configured recursive DNS server SHOULD be sent from a local IP 509 address that was provisioned by the PvD via RA or DHCP. Answers 510 received from the DNS server SHOULD only be used on the same PvD. 512 PvD-aware applications will be able to select which PvD(s) to use for 513 DNS resolution and connections, which allows them to effectively use 514 multiple Explicit PvDs. In order to support non-PvD-aware 515 applications, however, PvD-aware hosts SHOULD ensure that non-PvD- 516 aware name resolution APIs like "getaddrinfo" only use resolvers from 517 a single PvD for each query. Handling DNS across PvDs is discussed 518 in Section 5.2.1 of [RFC7556], and PvD APIs are discussed in 519 Section 6 of [RFC7556]. 521 Maintaining the correct usage of DNS within PvDs avoids various 522 practical errors, such as: 524 o A PvD associated with a VPN or otherwise private network may 525 provide DNS answers that contain addresses inaccessible over 526 another PvD. This includes the DNS queries to retrieve PvD 527 additional information, which could otherwise send identifying 528 information to the recursive DNS system (see Section 4.1). 530 o A PvD that uses a NAT64 [RFC6146] and DNS64 [RFC6147] will 531 synthesize IPv6 addresses in DNS answers that are not globally 532 routable, and would be invalid on other PvDs. Conversely, an IPv4 533 address resolved via DNS on another PvD cannot be directly used on 534 a NAT64 network. 536 4. Provisioning Domain Additional Information 538 Additional information about the network characteristics can be 539 retrieved based on the PvD ID. This set of information is called PvD 540 Additional Information, and is encoded as a JSON object [RFC8259]. 541 This JSON object is restricted to the restricted profile of I-JSON, 542 as defined in [RFC7493]. 544 The purpose of this JSON object is to provide additional information 545 to applications on a client host about the connectivity that is 546 provided using a given interface and source address. It typically 547 includes data that would be considered too large, or not critical 548 enough, to be provided within an RA option. The information 549 contained in this object MAY be used by the operating system, network 550 libraries, applications, or users, in order to decide which set of 551 PvDs should be used for which connection, as described in 552 Section 3.4. 554 The additional information related to a PvD is specifically intended 555 to be optional, and is targeted at optimizing or informing the 556 behavior of user-facing hosts. This information can be extended to 557 provide hints for host system behavior (such as captive portal or 558 walled-garden PvD detection) or application behavior (describing 559 application-specific services offered on a given PvD). This content 560 may not be appropriate for light-weight Internet of Things (IoT) 561 devices. IoT devices might need only a subset of the information, 562 and would in some cases prefer a smaller representation like CBOR 563 ([RFC7049]). Delivering a reduced version of the PvD Additional 564 Information designed for such devices is not defined in this 565 document. 567 4.1. Retrieving the PvD Additional Information 569 When the H-flag of the PvD Option is set, hosts MAY attempt to 570 retrieve the PvD Additional Information associated with a given PvD 571 by performing an HTTP over TLS [RFC2818] GET query to https:///.well-known/pvd. Inversely, hosts MUST NOT do so whenever the 573 H-flag is not set. 575 HTTP requests and responses for PvD additional information use the 576 "application/pvd+json" media type (see Section 8). Clients SHOULD 577 include this media type as an Accept header in their GET requests, 578 and servers MUST mark this media type as their Content-Type header in 579 responses. 581 Note that the DNS name resolution of the PvD ID, the PKI (Public Key 582 Infrastructure) checks as well as the actual query MUST be performed 583 using the considered PvD. In other words, the name resolution, PKI 584 checks, source address selection, as well as the next-hop router 585 selection MUST be performed while using exclusively the set of 586 configuration information attached with the PvD, as defined in 587 Section 3.4. In some cases, it may therefore be necessary to wait 588 for an address to be available for use (e.g., once the Duplicate 589 Address Detection or DHCPv6 processes are complete) before initiating 590 the HTTP over TLS query. In order to address privacy concerns around 591 linkability of the PvD HTTP connection with future user-initiated 592 connections, if the host has a temporary address per [RFC4941] in 593 this PvD, then it SHOULD use a temporary address to fetch the PvD 594 Additional Information and MAY deprecate the used temporary address 595 and generate a new temporary address afterward. 597 If the HTTP status of the answer is greater than or equal to 400 the 598 host MUST abandon and consider that there is no additional PvD 599 information. If the HTTP status of the answer is between 300 and 600 399, inclusive, it MUST follow the redirection(s). If the HTTP 601 status of the answer is between 200 and 299, inclusive, the host MAY 602 get a file containing a single JSON object. 604 After retrieval of the PvD Additional Information, hosts MUST 605 remember the last Sequence Number value received in the RA including 606 the same PvD ID. Whenever a new RA for the same PvD is received with 607 a different Sequence Number value, or whenever the expiry date for 608 the additional information is reached, hosts MUST deprecate the 609 additional information and stop using it until a new JSON object is 610 retrieved. 612 Hosts retrieving a new PvD Additional Information object MUST check 613 for the presence and validity of the mandatory fields specified in 614 Section 4.3. A retrieved object including an expiration time that is 615 already past or missing a mandatory element MUST be ignored. 617 In order to avoid synchronized queries toward the server hosting the 618 PvD Additional Information when an object expires, object updates are 619 delayed by a randomized backoff time. 621 o When a host performs a JSON object update after it detected a 622 change in the PvD Option Sequence Number, it MUST add a delay 623 before sending the query. The target time for the delay is 624 calculated as a random time between zero and 2**(Delay * 2) 625 milliseconds, where 'Delay' corresponds to the 4-bit unsigned 626 integer in the last received PvD Option. 628 o When a host last retrieved a JSON object at time A that includes a 629 expiry time B using the "expires" key, and the host is configured 630 to keep the PvD information up to date, it MUST add some 631 randomness into its calculation of the time to fetch the update. 633 The target time for fetching the updated object is calculated as a 634 uniformly random time in the interval [(B-A)/2,B]. 636 In the example Figure 2, the delay field value is 5, this means that 637 the host calculates its delay by choosing a random number between 0 638 and 2**(5 * 2) milliseconds, i.e., between 0 and 1024 milliseconds. 640 Since the 'Delay' value is directly within the PvD Option rather than 641 the object itself, an operator may perform a push-based update by 642 incrementing the Sequence value while changing the Delay value 643 depending on the criticality of the update and its PvD Additional 644 Information servers capacity. 646 The PvD Additional Information object includes a set of IPv6 prefixes 647 (under the key "prefixes") which MUST be checked against all the 648 Prefix Information Options advertised in the RA. If any of the 649 prefixes included in any associated PIO is not covered by at least 650 one of the listed prefixes, the associated PvD information MUST be 651 considered to be a misconfiguration, and MUST NOT be used by the 652 host. See Section 4.4 for more discussion on handling such 653 misconfigurations. 655 4.2. Operational Consideration to Providing the PvD Additional 656 Information 658 Whenever the H-flag is set in the PvD Option, a valid PvD Additional 659 Information object MUST be made available to all hosts receiving the 660 RA by the network operator. In particular, when a captive portal is 661 present, hosts MUST still be allowed to perform DNS, PKI and HTTP 662 over TLS operations related to the retrieval of the object, even 663 before logging into the captive portal. 665 Routers SHOULD increment the PVD Option Sequence Number by one 666 whenever a new PvD Additional Information object is available and 667 should be retrieved by hosts. If the value exceeds what can be 668 stored in the Sequence Number field, it SHOULD wrap back to zero. 670 The server providing the JSON files SHOULD also check whether the 671 client address is part of the prefixes listed into the additional 672 information and SHOULD return a 403 response code if there is no 673 match. 675 4.3. PvD Additional Information Format 677 The PvD Additional Information is a JSON object. 679 The following table presents the mandatory keys which MUST be 680 included in the object: 682 +------------+-----------------+-----------+------------------------+ 683 | JSON key | Description | Type | Example | 684 +------------+-----------------+-----------+------------------------+ 685 | identifier | PvD ID FQDN | String | "pvd.example.com." | 686 | | | | | 687 | expires | Date after | [RFC3339] | "2017-07-23T06:00:00Z" | 688 | | which this | Date | | 689 | | object is no | | | 690 | | longer valid | | | 691 | | | | | 692 | prefixes | Array of IPv6 | Array of | ["2001:db8:1::/48", | 693 | | prefixes valid | strings | "2001:db8:4::/48"] | 694 | | for this PvD | | | 695 +------------+-----------------+-----------+------------------------+ 697 A retrieved object which does not include all three of these keys at 698 the root of the JSON object MUST be ignored. All three keys need to 699 be validated, otherwise the object MUST be ignored. The value stored 700 for "identifier" MUST be matched against the PvD ID FQDN presented in 701 the PvD RA option using the comparison mechanism described in 702 Section 3.4. The value stored for "expires" MUST be a valid date in 703 the future. If the PIO of the received RA is not covered by at least 704 one of the "prefixes" key, the retrieved object SHOULD be ignored. 706 The following table presents some optional keys which MAY be included 707 in the object. 709 +------------+----------------------+----------+--------------------+ 710 | JSON key | Description | Type | Example | 711 +------------+----------------------+----------+--------------------+ 712 | dnsZones | DNS zones searchable | Array of | ["example.com", | 713 | | and accessible | strings | | 714 | | | | | 715 | | | | "sub.example.com"] | 716 | | | | | 717 | noInternet | No Internet, set | Boolean | true | 718 | | when the PvD is | | | 719 | | restricted. | | | 720 +------------+----------------------+----------+--------------------+ 722 It is worth noting that the JSON format allows for extensions. 723 Whenever an unknown key is encountered, it MUST be ignored along with 724 its associated elements. 726 Private-use or experimental keys MAY be used in the JSON dictionary. 727 In order to avoid such keys colliding with IANA registry keys, 728 implementers or vendors defining private-use or experimental keys 729 MUST create sub-dictionaries, where the sub-dictionary is added into 730 the top-level JSON dictionary with a key of the format "vendor-*" 731 where the "*" is replaced by the implementer's or vendor's 732 identifier. For example, keys specific to the FooBar organization 733 could use "vendor-foobar". Upon receiving such a sub-dictionary, 734 host MUST ignore this sub-dictionary if it is unknown. When the 735 vendor or implementer is part of an IANA URN namespace [URN], the URN 736 namespace SHOULD be used rather than the "vendor-*" format. 738 4.3.1. Example 740 The following two examples show how the JSON keys defined in this 741 document can be used: 743 { 744 "identifier": "cafe.example.com", 745 "expires": "2017-07-23T06:00:00Z", 746 "prefixes": ["2001:db8:1::/48", "2001:db8:4::/48"], 747 } 749 { 750 "identifier": "company.foo.example.com", 751 "expires": "2017-07-23T06:00:00Z", 752 "prefixes": ["2001:db8:1::/48", "2001:db8:4::/48"], 753 "vendor-foo": 754 { 755 "private-key": "private-value", 756 }, 757 } 759 4.4. Detecting misconfiguration and misuse 761 When a host retrieves the PvD Additional Information, it MUST verify 762 that the TLS server certificate is valid for the performed request 763 (e.g., that the Subject Alternative Name is equal to the PvD ID 764 expressed as an FQDN). This authentication creates a secure binding 765 between the information provided by the trusted Router Advertisement, 766 and the HTTPS server. However, this does not mean the Advertising 767 Router and the PvD server belong to the same entity. 769 Hosts MUST verify that all prefixes in all the RA PIOs are covered by 770 a prefix from the PvD Additional Information. An adversarial router 771 attempting to spoof the definition of an Explicit PvD, without the 772 ability to modify the PvD Additional Information, would need to 773 perform NAT66 in order to circumvent this check. Thus, this check 774 cannot prevent all spoofing, but it can detect misconfiguration or 775 mismatched routers that are not adding a NAT. 777 If NAT66 is being added in order to spoof PvD ownership, the HTTPS 778 server for additional information can detect this misconfiguration. 779 The HTTPS server SHOULD validate the source addresses of incoming 780 connections (see Section 4.1). This check gives reasonable assurance 781 that neither NPTv6 [RFC6296] nor NAT66 were used and restricts the 782 information to the valid network users. If the PvD does not 783 provision IPv4 (it does not include the 'L' bit in the RA), the 784 server cannot validate the source addresses of connections using 785 IPv4. Thus, the PvD ID FQDN for such PvDs SHOULD NOT have a DNS A 786 record. 788 5. Operational Considerations 790 This section describes some example use cases of PvDs. For the sake 791 of simplicity, the RA messages will not be described in the usual 792 ASCII art but rather in an indented list. 794 5.1. Exposing Extra RA Options to PvD-Aware Hosts 796 In this example, there is one RA message sent by the router. This 797 message contains some options applicable to all hosts on the network, 798 and also a PvD Option that also contains other options only visible 799 to PvD-aware hosts. 801 o RA Header: router lifetime = 6000 803 o Prefix Information Option: length = 4, prefix = 2001:db8:cafe::/64 805 o PvD Option header: length = 3 + 5 + 4, PvD ID FQDN = example.org., 806 R-flag = 0 (actual length of the header with padding 24 bytes = 3 807 * 8 bytes) 809 * Recursive DNS Server: length = 5, addresses = 810 [2001:db8:cafe::53, 2001:db8:f00d::53] 812 * Prefix Information Option: length = 4, prefix = 813 2001:db8:f00d::/64 815 Note that a PvD-aware host will receive two different prefixes, 816 2001:db8:cafe::/64 and 2001:db8:f00d::/64, both associated with the 817 same PvD (identified by "example.org."). A non-PvD-aware host will 818 only receive one prefix, 2001:db8:cafe::/64. 820 5.2. Different RAs for PvD-Aware and Non-PvD-Aware Hosts 822 It is expected that for some years, networks will have a mixed 823 environment of PvD-aware hosts and non-PvD-aware hosts. If there is 824 a need to give specific information to PvD-aware hosts only, then it 825 is RECOMMENDED to send two RA messages, one for each class of hosts. 826 This approach allows for two distinct sets of configuration 827 information to be sent in a way that will not disrupt non-PvD-aware 828 hosts. It also lowers the risk that a single RA message will 829 approach its MTU limit due to duplicated information. 831 If two RA messages are sent for this reason, they MUST be sent from 832 two different link-local source addresses (Section 3.2). For 833 example, here is the RA sent for non-PvD-aware hosts: 835 o RA Header: router lifetime = 6000 (non-PvD-aware hosts will use 836 this router as a default router) 838 o Prefix Information Option: length = 4, prefix = 2001:db8:cafe::/64 840 o Recursive DNS Server Option: length = 3, addresses= 841 [2001:db8:cafe::53] 843 o PvD Option header: length = 3 + 2, PvD ID FQDN = foo.example.org., 844 R-flag = 1 (actual length of the header 24 bytes = 3 * 8 bytes) 846 * RA Header: router lifetime = 0 (PvD-aware hosts will not use 847 this router as a default router), implicit length = 2 849 And here is the RA sent for PvD-aware hosts: 851 o RA Header: router lifetime = 0 (non-PvD-aware hosts will not use 852 this router as a default router) 854 o PvD Option header: length = 3 + 2 + 4 + 3, PvD ID FQDN = 855 bar.example.org., R-flag = 1 (actual length of the header 24 bytes 856 = 3 * 8 bytes) 858 * RA Header: router lifetime = 1600 (PvD-aware hosts will use 859 this router as a default router), implicit length = 2 861 * Prefix Information Option: length = 4, prefix = 862 2001:db8:f00d::/64 864 * Recursive DNS Server Option: length = 3, addresses = 865 [2001:db8:f00d::53] 867 In the above example, non-PvD-aware hosts will only use the first RA 868 sent from their default router and using the 2001:db8:cafe::/64 869 prefix. PvD-aware hosts will autonomously configure addresses from 870 both PIOs, but will only use the source address in 2001:db8:f00d::/64 871 to communicate past the first hop router since only the router 872 sending the second RA will be used as default router; similarly, they 873 will use the DNS server 2001:db8:f00d::53 when communicating with 874 this address. 876 5.3. Enabling Multi-homing for PvD-Aware Hosts 878 In this example, the goal is to have one prefix from one RA be usable 879 by both non-PvD-aware and PvD-aware hosts; and to have another prefix 880 usable only by PvD-aware hosts. This allows PvD-aware hosts to be 881 able to effectively multi-home on the network. 883 The first RA is usable by all hosts. The only difference for PvD- 884 aware hosts is that they can explicitly identify the PvD ID 885 associated with the RA. PvD-aware hosts will also use this prefix to 886 communicate with non-PvD-aware hosts on the same network. 888 o RA Header: router lifetime = 6000 (non-PvD-aware hosts will use 889 this router as a default router) 891 o Prefix Information Option: length = 4, prefix = 2001:db8:cafe::/64 893 o Recursive DNS Server Option: length = 3, addresses= 894 [2001:db8:cafe::53] 896 o PvD Option header: length = 3, PvD ID FQDN = foo.example.org., 897 R-flag = 0 (actual length of the header 24 bytes = 3 * 8 bytes) 899 The second RA contains a prefix usable only by PvD-aware hosts. Non- 900 PvD-aware hosts will ignore this RA; hence, the only PvD-aware hosts 901 will be multi-homed. 903 o RA Header: router lifetime = 0 (non-PvD-aware hosts will not use 904 this router as a default router) 906 o PvD Option header: length = 3 + 2 + 4 + 3, PvD ID FQDN = 907 bar.example.org., R-flag = 1 (actual length of the header 24 bytes 908 = 3 * 8 bytes) 910 * RA Header: router lifetime = 1600 (PvD-aware hosts will use 911 this router as a default router), implicit length = 2 913 * Prefix Information Option: length = 4, prefix = 914 2001:db8:f00d::/64 916 * Recursive DNS Server Option: length = 3, addresses = 917 [2001:db8:f00d::53] 919 Note: the above examples assume that the router has received its PvD 920 IDs from upstream routers or via some other configuration mechanism. 922 Another document could define ways for the router to generate its own 923 PvD IDs to allow the above scenario in the absence of PvD ID 924 provisioning. 926 5.4. Providing Additional Information to PvD-Aware Hosts 928 In this example, the router indicates that it provides additional 929 information using the H-flag. The Sequence Number on the PvD Option 930 is set to 7 in this example. 932 o RA Header: router lifetime = 6000 934 o Prefix Information Option: length = 4, prefix = 2001:db8:cafe::/64 936 o Recursive DNS Server Option: length = 3, addresses= 937 [2001:db8:cafe::53] 939 o PvD Option header: length = 3, PvD ID FQDN = cafe.example.com., 940 Sequence Number = 7, R-flag = 0, H-flag = 1 (actual length of the 941 header with padding 24 bytes = 3 * 8 bytes) 943 A PvD-aware host will fetch https://cafe.example.com/.well-known/pvd 944 to get the additonal information. The following example shows a GET 945 request that the host sends: 947 :method = GET 948 :scheme = https 949 :authority = cafe.example.com 950 :path = /.well-known/pvd 951 accept = application/pvd+json 953 The HTTP server will respond with the JSON additional information: 955 :status = 200 956 content-type = application/pvd+json 957 content-length = 116 959 { 960 "identifier": "cafe.example.com", 961 "expires": "2017-07-23T06:00:00Z", 962 "prefixes": ["2001:db8:cafe::/48"], 963 } 965 At this point, the host has the additional information, and knows the 966 expiry time. When either the expiry time passes, or a new Sequence 967 Number is provided in an RA, the host will re-fetch the additional 968 information. 970 For example, if the router sends a new RA with the Sequence Number 971 set to 8, the host will re-fetch the additional information: 973 o PvD Option header: length = 3 + 5 + 4 , PvD ID FQDN = 974 cafe.example.com., Sequence Number = 8, R-flag = 0, H-flag = 1 975 (actual length of the header with padding 24 bytes = 3 * 8 bytes) 977 However, if the router sends a new RA, but the Sequence Number has 978 not changed, the host would not re-fetch the additional information 979 (until and unless the expiry time of the additional information has 980 passed). 982 6. Security Considerations 984 Although some solutions such as IPsec or SeND [RFC3971] can be used 985 in order to secure the IPv6 Neighbor Discovery Protocol, in practice 986 actual deployments largely rely on link layer or physical layer 987 security mechanisms (e.g., 802.1x [IEEE8021X]) in conjunction with RA 988 Guard [RFC6105]. 990 This specification does not improve the Neighbor Discovery Protocol 991 security model, but extends the purely link-local trust relationship 992 between the host and the default routers with HTTP over TLS 993 communications which servers are authenticated as rightful owners of 994 the FQDN received within the trusted PvD ID RA option. 996 It must be noted that Section 4.4 of this document only provides 997 reasonable assurance against misconfiguration but does not prevent an 998 hostile network access provider to advertise wrong information that 999 could lead applications or hosts to select a hostile PvD. 1001 Users cannot be assumed to be able to meaningfully differentiate 1002 between "safe" and "unsafe" networks. This is a known attack surface 1003 that is present whether or not PvDs are in use, and hence cannot be 1004 addressed by this document. However, a host that correctly 1005 implements the multiple PvD architecture ([RFC7556]) using the 1006 mechanism described in this document will be less susceptible to such 1007 attacks than a host that does not by being able to check for the 1008 various misconfigurations described in this document. 1010 7. Privacy Considerations 1012 Retrieval of the PvD Additional Information over HTTPS requires early 1013 communications between the connecting host and a server which may be 1014 located further than the first hop router. Although this server is 1015 likely to be located within the same administrative domain as the 1016 default router, this property can't be ensured. Therefore, hosts 1017 willing to retrieve the PvD Additional Information before using it 1018 without leaking identity information, SHOULD make use of an IPv6 1019 Privacy Address and SHOULD NOT include any privacy sensitive data, 1020 such as User Agent header or HTTP cookie, while performing the HTTP 1021 over TLS query. 1023 From a user privacy perspective, retrieving the PvD Additional 1024 Information is not different from establishing a first connection to 1025 a remote server, or even performing a single DNS lookup. For 1026 example, most operating systems already perform early queries to well 1027 known web sites, such as http://captive.example.com/hotspot- 1028 detect.html, in order to detect the presence of a captive portal. 1030 The DNS queries associated with the PvD Additional Information MUST 1031 use the DNS servers indicated by the associated PvD, as described in 1032 Section 4.1. This ensures the name of the PvD Additional Information 1033 server is not unintentionally sent on another network, thus leaking 1034 identifying information about the networks with which the client is 1035 associated. 1037 There may be some cases where hosts, for privacy reasons, should 1038 refrain from accessing servers that are located outside a certain 1039 network boundary. In practice, this could be implemented as a 1040 whitelist of 'trusted' FQDNs and/or IP prefixes that the host is 1041 allowed to communicate with. In such scenarios, the host SHOULD 1042 check that the provided PvD ID, as well as the IP address that it 1043 resolves into, are part of the allowed whitelist. 1045 Network operators SHOULD restrict access to PvD Additional 1046 Information to only expose it to hosts that are connected to the 1047 local network, especially if the Additional Information would provide 1048 information about local network configuration to attackers. This can 1049 be implemented by whitelisting access from the addresses and prefixes 1050 that the router provides for the PvD, which will match the prefixes 1051 contained in the PvD Additional Information. 1053 8. IANA Considerations 1055 Upon publication of this document, IANA is asked to remove the 1056 'reclaimable' tag off the value 21 for the PvD Option (from the IPv6 1057 Neighbor Discovery Option Formats registry). 1059 8.1. New entry in the Well-Known URIs Registry 1061 IANA is asked to add a new entry in the Well-Known URIs registry 1062 [RFC8615] with the following information: 1064 URI suffix: 'pvd' 1065 Change controller: IETF 1067 Specification document: this document 1069 Status: permanent 1071 Related information: N/A 1073 8.2. Additional Information PvD Keys Registry 1075 IANA is asked to create and maintain a new registry called 1076 "Additional Information PvD Keys", which will reserve JSON keys for 1077 use in PvD additional information. The initial contents of this 1078 registry are given in Section 4.3, including both the table of 1079 mandatory keys and the table of optional keys. 1081 The status of a key as mandatory or optional is intentionally not 1082 denoted in the table to allow for flexibility in future use cases. 1083 Any new assignments of keys will be considered as optional for the 1084 purpose of the mechanism described in this document. 1086 New assignments for Additional Information PvD Keys Registry will be 1087 administered by IANA through Expert Review [RFC8126]. 1089 IANA is asked to place this registry in a new page, entitled 1090 "Provisioning Domains (PvDs)". 1092 8.3. PvD Option Flags Registry 1094 IANA is also asked to create and maintain a new registry entitled 1095 "PvD Option Flags" reserving bit positions from 0 to 15 to be used in 1096 the PvD Option bitmask. Bit position 0, 1 and 2 are assigned by this 1097 document (as specified in Figure 1). Future assignments require 1098 Standards Action [RFC8126], via a Standards Track RFC document. 1100 Since these flags apply to an IPv6 Router Advertisement Option, IANA 1101 is asked to place this registry under the existing "Internet Control 1102 Message Protocol version 6 (ICMPv6) Parameters" page, as well as 1103 providing a link on the new "Provisioning Domains (PvDs)" page. 1105 8.4. PvD JSON Media Type Registration 1107 This document registers the media type for PvD JSON text, 1108 "application/pvd+json". 1110 Type Name: application 1112 Subtype Name: pvd+json 1113 Required parameters: None 1115 Optional parameters: None 1117 Encoding considerations: Encoding considerations are identical to 1118 those specified for the "application/json" media type. 1120 Security considerations: See Section 6. 1122 Interoperability considerations: This document specifies format of 1123 conforming messages and the interpretation thereof. 1125 Published specification: This document 1127 Applications that use this media type: This media type is intended to 1128 be used by network advertising additional Provisioning Domain 1129 information, and clients looking up such information. 1131 Additional information: None 1133 Person and email address to contact for further information: See 1134 Authors' Addresses section 1136 Intended usage: COMMON 1138 Restrictions on usage: None 1140 Author: IETF 1142 Change controller: IETF 1144 9. Acknowledgments 1146 Many thanks to M. Stenberg and S. Barth for their earlier work: 1147 [I-D.stenberg-mif-mpvd-dns], as well as to Basile Bruneau who was 1148 author of an early version of this document. 1150 Thanks also to Marcus Keane, Mikael Abrahamsson, Ray Bellis, Zhen 1151 Cao, Tim Chown, Lorenzo Colitti, Michael Di Bartolomeo, Ian Farrer, 1152 Phillip Hallam-Baker, Bob Hinden, Tatuya Jinmei, Erik Kline, Ted 1153 Lemon, Paul Hoffman, Dave Thaler, Suresh Krishnan, Gorry Fairhurst, 1154 Jen Lenkova, Veronika McKillop, Mark Townsley and James Woodyatt for 1155 useful and interesting discussions and reviews. 1157 Finally, special thanks to Thierry Danis for his valuable inputs and 1158 implementation efforts, Tom Jones for his integration effort into the 1159 NEAT project and Rigil Salim for his implementation work. 1161 10. References 1163 10.1. Normative References 1165 [RFC1035] Mockapetris, P., "Domain names - implementation and 1166 specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, 1167 November 1987, . 1169 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1170 Requirement Levels", BCP 14, RFC 2119, 1171 DOI 10.17487/RFC2119, March 1997, 1172 . 1174 [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", 1175 RFC 2131, DOI 10.17487/RFC2131, March 1997, 1176 . 1178 [RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet: 1179 Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002, 1180 . 1182 [RFC3646] Droms, R., Ed., "DNS Configuration options for Dynamic 1183 Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3646, 1184 DOI 10.17487/RFC3646, December 2003, 1185 . 1187 [RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and 1188 More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191, 1189 November 2005, . 1191 [RFC4343] Eastlake 3rd, D., "Domain Name System (DNS) Case 1192 Insensitivity Clarification", RFC 4343, 1193 DOI 10.17487/RFC4343, January 2006, 1194 . 1196 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 1197 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 1198 DOI 10.17487/RFC4861, September 2007, 1199 . 1201 [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy 1202 Extensions for Stateless Address Autoconfiguration in 1203 IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007, 1204 . 1206 [RFC6724] Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown, 1207 "Default Address Selection for Internet Protocol Version 6 1208 (IPv6)", RFC 6724, DOI 10.17487/RFC6724, September 2012, 1209 . 1211 [RFC6980] Gont, F., "Security Implications of IPv6 Fragmentation 1212 with IPv6 Neighbor Discovery", RFC 6980, 1213 DOI 10.17487/RFC6980, August 2013, 1214 . 1216 [RFC7493] Bray, T., Ed., "The I-JSON Message Format", RFC 7493, 1217 DOI 10.17487/RFC7493, March 2015, 1218 . 1220 [RFC8028] Baker, F. and B. Carpenter, "First-Hop Router Selection by 1221 Hosts in a Multi-Prefix Network", RFC 8028, 1222 DOI 10.17487/RFC8028, November 2016, 1223 . 1225 [RFC8106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli, 1226 "IPv6 Router Advertisement Options for DNS Configuration", 1227 RFC 8106, DOI 10.17487/RFC8106, March 2017, 1228 . 1230 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 1231 Writing an IANA Considerations Section in RFCs", BCP 26, 1232 RFC 8126, DOI 10.17487/RFC8126, June 2017, 1233 . 1235 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1236 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1237 May 2017, . 1239 [RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data 1240 Interchange Format", STD 90, RFC 8259, 1241 DOI 10.17487/RFC8259, December 2017, 1242 . 1244 [RFC8615] Nottingham, M., "Well-Known Uniform Resource Identifiers 1245 (URIs)", RFC 8615, DOI 10.17487/RFC8615, May 2019, 1246 . 1248 10.2. Informative References 1250 [I-D.kline-mif-mpvd-api-reqs] 1251 Kline, E., "Multiple Provisioning Domains API 1252 Requirements", draft-kline-mif-mpvd-api-reqs-00 (work in 1253 progress), November 2015. 1255 [I-D.stenberg-mif-mpvd-dns] 1256 Stenberg, M. and S. Barth, "Multiple Provisioning Domains 1257 using Domain Name System", draft-stenberg-mif-mpvd-dns-00 1258 (work in progress), October 2015. 1260 [IEEE8021X] 1261 "IEEE Standards for Local and Metropolitan Area Networks, 1262 Port-based Network Access Control, IEEE Std", n.d.. 1264 [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, 1265 DOI 10.17487/RFC2818, May 2000, 1266 . 1268 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 1269 "SEcure Neighbor Discovery (SEND)", RFC 3971, 1270 DOI 10.17487/RFC3971, March 2005, 1271 . 1273 [RFC4389] Thaler, D., Talwar, M., and C. Patel, "Neighbor Discovery 1274 Proxies (ND Proxy)", RFC 4389, DOI 10.17487/RFC4389, April 1275 2006, . 1277 [RFC6105] Levy-Abegnoli, E., Van de Velde, G., Popoviciu, C., and J. 1278 Mohacsi, "IPv6 Router Advertisement Guard", RFC 6105, 1279 DOI 10.17487/RFC6105, February 2011, 1280 . 1282 [RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful 1283 NAT64: Network Address and Protocol Translation from IPv6 1284 Clients to IPv4 Servers", RFC 6146, DOI 10.17487/RFC6146, 1285 April 2011, . 1287 [RFC6147] Bagnulo, M., Sullivan, A., Matthews, P., and I. van 1288 Beijnum, "DNS64: DNS Extensions for Network Address 1289 Translation from IPv6 Clients to IPv4 Servers", RFC 6147, 1290 DOI 10.17487/RFC6147, April 2011, 1291 . 1293 [RFC6296] Wasserman, M. and F. Baker, "IPv6-to-IPv6 Network Prefix 1294 Translation", RFC 6296, DOI 10.17487/RFC6296, June 2011, 1295 . 1297 [RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object 1298 Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049, 1299 October 2013, . 1301 [RFC7278] Byrne, C., Drown, D., and A. Vizdal, "Extending an IPv6 1302 /64 Prefix from a Third Generation Partnership Project 1303 (3GPP) Mobile Interface to a LAN Link", RFC 7278, 1304 DOI 10.17487/RFC7278, June 2014, 1305 . 1307 [RFC7556] Anipko, D., Ed., "Multiple Provisioning Domain 1308 Architecture", RFC 7556, DOI 10.17487/RFC7556, June 2015, 1309 . 1311 [RFC8415] Mrugalski, T., Siodelski, M., Volz, B., Yourtchenko, A., 1312 Richardson, M., Jiang, S., Lemon, T., and T. Winters, 1313 "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", 1314 RFC 8415, DOI 10.17487/RFC8415, November 2018, 1315 . 1317 [URN] "URN Namespaces", n.d.. 1319 Authors' Addresses 1321 Pierre Pfister 1322 Cisco 1323 11 Rue Camille Desmoulins 1324 Issy-les-Moulineaux 92130 1325 France 1327 Email: ppfister@cisco.com 1329 Eric Vyncke 1330 Cisco 1331 De Kleetlaan, 6 1332 Diegem 1831 1333 Belgium 1335 Email: evyncke@cisco.com 1337 Tommy Pauly 1338 Apple Inc. 1339 One Apple Park Way 1340 Cupertino, California 95014 1341 United States of America 1343 Email: tpauly@apple.com 1344 David Schinazi 1345 Google LLC 1346 1600 Amphitheatre Parkway 1347 Mountain View, California 94043 1348 United States of America 1350 Email: dschinazi.ietf@gmail.com 1352 Wenqin Shao 1353 Cisco 1354 11 Rue Camille Desmoulins 1355 Issy-les-Moulineaux 92130 1356 France 1358 Email: wenshao@cisco.com