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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Engineering Task Force T. Chown 3 Internet-Draft Jisc 4 Obsoletes: 6434 (if approved) J. Loughney 5 Intended status: Best Current Practice Intel 6 Expires: August 26, 2018 T. Winters 7 UNH-IOL 8 February 22, 2018 10 IPv6 Node Requirements 11 draft-ietf-6man-rfc6434-bis-04 13 Abstract 15 This document defines requirements for IPv6 nodes. It is expected 16 that IPv6 will be deployed in a wide range of devices and situations. 17 Specifying the requirements for IPv6 nodes allows IPv6 to function 18 well and interoperate in a large number of situations and 19 deployments. 21 This document obsoletes RFC 6434, and in turn RFC 4294. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at https://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on August 26, 2018. 40 Copyright Notice 42 Copyright (c) 2018 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (https://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 58 1.1. Scope of This Document . . . . . . . . . . . . . . . . . 4 59 1.2. Description of IPv6 Nodes . . . . . . . . . . . . . . . . 5 60 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 5 61 3. Abbreviations Used in This Document . . . . . . . . . . . . . 5 62 4. Sub-IP Layer . . . . . . . . . . . . . . . . . . . . . . . . 5 63 5. IP Layer . . . . . . . . . . . . . . . . . . . . . . . . . . 6 64 5.1. Internet Protocol Version 6 - RFC 8200 . . . . . . . . . 6 65 5.2. Support for IPv6 Extension Headers . . . . . . . . . . . 7 66 5.3. Protecting a node from excessive EH options . . . . . . . 8 67 5.4. Neighbor Discovery for IPv6 - RFC 4861 . . . . . . . . . 9 68 5.5. SEcure Neighbor Discovery (SEND) - RFC 3971 . . . . . . . 10 69 5.6. IPv6 Router Advertisement Flags Option - RFC 5175 . . . . 10 70 5.7. Path MTU Discovery and Packet Size . . . . . . . . . . . 11 71 5.7.1. Path MTU Discovery - RFC 8201 . . . . . . . . . . . . 11 72 5.7.2. Minimum MTU considerations . . . . . . . . . . . . . 11 73 5.8. ICMP for the Internet Protocol Version 6 (IPv6) - RFC 74 4443 . . . . . . . . . . . . . . . . . . . . . . . . . . 11 75 5.9. Default Router Preferences and More-Specific Routes - RFC 76 4191 . . . . . . . . . . . . . . . . . . . . . . . . . . 11 77 5.10. First-Hop Router Selection - RFC 8028 . . . . . . . . . . 12 78 5.11. Multicast Listener Discovery (MLD) for IPv6 - RFC 3810 . 12 79 5.12. Explicit Congestion Notification (ECN) - RFC 3168 . . . . 12 80 6. Addressing and Address Configuration . . . . . . . . . . . . 12 81 6.1. IP Version 6 Addressing Architecture - RFC 4291 . . . . . 12 82 6.2. Host Address Availability Recommendations . . . . . . . . 13 83 6.3. IPv6 Stateless Address Autoconfiguration - RFC 4862 . . . 13 84 6.4. Privacy Extensions for Address Configuration in IPv6 - 85 RFC 4941 . . . . . . . . . . . . . . . . . . . . . . . . 14 86 6.5. Stateful Address Autoconfiguration (DHCPv6) - RFC 3315 . 15 87 6.6. Default Address Selection for IPv6 - RFC 6724 . . . . . . 15 88 7. DNS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 89 8. Configuring Non-Address Information . . . . . . . . . . . . . 16 90 8.1. DHCP for Other Configuration Information . . . . . . . . 16 91 8.2. Router Advertisements and Default Gateway . . . . . . . . 16 92 8.3. IPv6 Router Advertisement Options for DNS 93 Configuration - RFC 8106 . . . . . . . . . . . . . . . . 16 94 8.4. DHCP Options versus Router Advertisement Options for Host 95 Configuration . . . . . . . . . . . . . . . . . . . . . . 17 96 9. Service Discovery Protocols . . . . . . . . . . . . . . . . . 17 97 10. IPv4 Support and Transition . . . . . . . . . . . . . . . . . 18 98 10.1. Transition Mechanisms . . . . . . . . . . . . . . . . . 18 99 10.1.1. Basic Transition Mechanisms for IPv6 Hosts and 100 Routers - RFC 4213 . . . . . . . . . . . . . . . . . 18 101 11. Application Support . . . . . . . . . . . . . . . . . . . . . 18 102 11.1. Textual Representation of IPv6 Addresses - RFC 5952 . . 18 103 11.2. Application Programming Interfaces (APIs) . . . . . . . 18 104 12. Mobility . . . . . . . . . . . . . . . . . . . . . . . . . . 19 105 13. Security . . . . . . . . . . . . . . . . . . . . . . . . . . 19 106 13.1. Requirements . . . . . . . . . . . . . . . . . . . . . . 21 107 13.2. Transforms and Algorithms . . . . . . . . . . . . . . . 21 108 14. Router-Specific Functionality . . . . . . . . . . . . . . . . 21 109 14.1. IPv6 Router Alert Option - RFC 2711 . . . . . . . . . . 21 110 14.2. Neighbor Discovery for IPv6 - RFC 4861 . . . . . . . . . 22 111 14.3. Stateful Address Autoconfiguration (DHCPv6) - RFC 3315 . 22 112 14.4. IPv6 Prefix Length Recommendation for Forwarding - BCP 113 198 . . . . . . . . . . . . . . . . . . . . . . . . . . 22 114 15. Constrained Devices . . . . . . . . . . . . . . . . . . . . . 22 115 16. Network Management . . . . . . . . . . . . . . . . . . . . . 23 116 16.1. Management Information Base (MIB) Modules . . . . . . . 23 117 16.1.1. IP Forwarding Table MIB . . . . . . . . . . . . . . 23 118 16.1.2. Management Information Base for the Internet 119 Protocol (IP) . . . . . . . . . . . . . . . . . . . 23 120 16.1.3. Interface MIB . . . . . . . . . . . . . . . . . . . 24 121 16.2. YANG Data Models . . . . . . . . . . . . . . . . . . . . 24 122 16.2.1. IP Management YANG Model . . . . . . . . . . . . . . 24 123 16.2.2. Interface Management YANG Model . . . . . . . . . . 24 124 17. Security Considerations . . . . . . . . . . . . . . . . . . . 24 125 18. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 126 19. Authors and Acknowledgments . . . . . . . . . . . . . . . . . 24 127 19.1. Authors and Acknowledgments (Current Document) . . . . . 24 128 19.2. Authors and Acknowledgments from RFC 6434 . . . . . . . 24 129 19.3. Authors and Acknowledgments from RFC 4294 . . . . . . . 25 130 20. Appendix: Changes from RFC 6434 . . . . . . . . . . . . . . . 26 131 21. Appendix: Changes from RFC 4294 . . . . . . . . . . . . . . . 27 132 22. References . . . . . . . . . . . . . . . . . . . . . . . . . 29 133 22.1. Normative References . . . . . . . . . . . . . . . . . . 29 134 22.2. Informative References . . . . . . . . . . . . . . . . . 35 135 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40 137 1. Introduction 139 This document defines common functionality required by both IPv6 140 hosts and routers. Many IPv6 nodes will implement optional or 141 additional features, but this document collects and summarizes 142 requirements from other published Standards Track documents in one 143 place. 145 This document tries to avoid discussion of protocol details and 146 references RFCs for this purpose. This document is intended to be an 147 applicability statement and to provide guidance as to which IPv6 148 specifications should be implemented in the general case and which 149 specifications may be of interest to specific deployment scenarios. 150 This document does not update any individual protocol document RFCs. 152 Although this document points to different specifications, it should 153 be noted that in many cases, the granularity of a particular 154 requirement will be smaller than a single specification, as many 155 specifications define multiple, independent pieces, some of which may 156 not be mandatory. In addition, most specifications define both 157 client and server behavior in the same specification, while many 158 implementations will be focused on only one of those roles. 160 This document defines a minimal level of requirement needed for a 161 device to provide useful internet service and considers a broad range 162 of device types and deployment scenarios. Because of the wide range 163 of deployment scenarios, the minimal requirements specified in this 164 document may not be sufficient for all deployment scenarios. It is 165 perfectly reasonable (and indeed expected) for other profiles to 166 define additional or stricter requirements appropriate for specific 167 usage and deployment environments. For example, this document does 168 not mandate that all clients support DHCP, but some deployment 169 scenarios may deem it appropriate to make such a requirement. For 170 example, government agencies in the USA have defined profiles for 171 specialized requirements for IPv6 in target environments (see 172 [USGv6]). 174 As it is not always possible for an implementer to know the exact 175 usage of IPv6 in a node, an overriding requirement for IPv6 nodes is 176 that they should adhere to Jon Postel's Robustness Principle: "Be 177 conservative in what you do, be liberal in what you accept from 178 others" [RFC0793]. 180 1.1. Scope of This Document 182 IPv6 covers many specifications. It is intended that IPv6 will be 183 deployed in many different situations and environments. Therefore, 184 it is important to develop requirements for IPv6 nodes to ensure 185 interoperability. 187 This document assumes that all IPv6 nodes meet the minimum 188 requirements specified here. 190 1.2. Description of IPv6 Nodes 192 From the Internet Protocol, Version 6 (IPv6) Specification [RFC8200], 193 we have the following definitions: 195 IPv6 node - a device that implements IPv6. 196 IPv6 router - a node that forwards IPv6 packets not explicitly 197 addressed to itself. 198 IPv6 host - any node that is not a router. 200 2. Requirements Language 202 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 203 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 204 document are to be interpreted as described in RFC 2119 [RFC2119]. 206 3. Abbreviations Used in This Document 208 AH Authentication Header 209 DAD Duplicate Address Detection 210 ESP Encapsulating Security Payload 211 ICMP Internet Control Message Protocol 212 IKE Internet Key Exchange 213 MIB Management Information Base 214 MLD Multicast Listener Discovery 215 MTU Maximum Transmission Unit 216 NA Neighbor Advertisement 217 NBMA Non-Broadcast Multiple Access 218 ND Neighbor Discovery 219 NS Neighbor Solicitation 220 NUD Neighbor Unreachability Detection 221 PPP Point-to-Point Protocol 223 4. Sub-IP Layer 225 An IPv6 node must include support for one or more IPv6 link-layer 226 specifications. Which link-layer specifications an implementation 227 should include will depend upon what link-layers are supported by the 228 hardware available on the system. It is possible for a conformant 229 IPv6 node to support IPv6 on some of its interfaces and not on 230 others. 232 As IPv6 is run over new layer 2 technologies, it is expected that new 233 specifications will be issued. In the following, we list some of the 234 layer 2 technologies for which an IPv6 specification has been 235 developed. It is provided for informational purposes only and may 236 not be complete. 238 - Transmission of IPv6 Packets over Ethernet Networks [RFC2464] 240 - Transmission of IPv6 Packets over Frame Relay Networks 241 Specification [RFC2590] 243 - Transmission of IPv6 Packets over IEEE 1394 Networks [RFC3146] 245 - Transmission of IPv6, IPv4, and Address Resolution Protocol (ARP) 246 Packets over Fibre Channel [RFC4338] 248 - Transmission of IPv6 Packets over IEEE 802.15.4 Networks [RFC4944] 250 - Transmission of IPv6 via the IPv6 Convergence Sublayer over IEEE 251 802.16 Networks [RFC5121] 253 - IP version 6 over PPP [RFC5072] 255 In addition to traditional physical link-layers, it is also possible 256 to tunnel IPv6 over other protocols. Examples include: 258 - Teredo: Tunneling IPv6 over UDP through Network Address 259 Translations (NATs) [RFC4380] 261 - Section 3 of "Basic Transition Mechanisms for IPv6 Hosts and 262 Routers" [RFC4213] 264 5. IP Layer 266 5.1. Internet Protocol Version 6 - RFC 8200 268 The Internet Protocol Version 6 is specified in [RFC8200]. This 269 specification MUST be supported. 271 The node MUST follow the packet transmission rules in RFC 8200. 273 All conformant IPv6 implementations MUST be capable of sending and 274 receiving IPv6 packets; forwarding functionality MAY be supported. 275 Nodes MUST always be able to send, receive, and process fragment 276 headers. Overlapping fragments MUST be handled as described in 277 [RFC5722]. 279 [RFC6946] discusses IPv6 atomic fragments, and recommends that IPv6 280 atomic fragments are processed independently of any other fragments, 281 to protect against fragmentation-based attacks. [RFC8021] goes 282 further and recommends the deprecation of atomic fragments. Nodes 283 thus MUST NOT generate atomic fragments. 285 To mitigate a variety of potential attacks, nodes SHOULD avoid using 286 predictable fragment Identification values in Fragment Headers, as 287 discussed in [RFC7739]. 289 All nodes SHOULD support the setting and use of the IPv6 Flow Label 290 field as defined in the IPv6 Flow Label specification [RFC6437]. 291 Forwarding nodes such as routers and load distributors MUST NOT 292 depend only on Flow Label values being uniformly distributed. It is 293 RECOMMENDED that source hosts support the flow label by setting the 294 Flow Label field for all packets of a given flow to the same value 295 chosen from an approximation to a discrete uniform distribution. 297 5.2. Support for IPv6 Extension Headers 299 RFC 8200 specifies extension headers and the processing for these 300 headers. 302 Any unrecognized extension headers or options MUST be processed as 303 described in RFC 8200. Note that where Section 4 of RFC 8200 refers 304 to the action to be taken when a Next Header value in the current 305 header is not recognized by a node, that action applies whether the 306 value is an unrecognized Extension Header or an unrecognized upper 307 layer protocol (ULP). 309 An IPv6 node MUST be able to process these headers. An exception is 310 Routing Header type 0 (RH0), which was deprecated by [RFC5095] due to 311 security concerns and which MUST be treated as an unrecognized 312 routing type. 314 Further, [RFC7045] adds specific requirements for processing of 315 Extension Headers, in particular that any forwarding node along an 316 IPv6 packet's path, which forwards the packet for any reason, SHOULD 317 do so regardless of any extension headers that are present. 319 [RFC7112] discusses issues with oversized IPv6 Extension Header 320 chains, and states that when a node fragments an IPv6 datagram, it 321 MUST include the entire IPv6 Header Chain in the First Fragment. 323 As stated in RFC8200, extension headers (except for the Hop-by-Hop 324 Options header) are not processed, inserted, or deleted by any node 325 along a packet's delivery path, until the packet reaches the node (or 326 each of the set of nodes, in the case of multicast) identified in the 327 Destination Address field of the IPv6 header. 329 It should be noted that when future, new Extension Headers are 330 defined, the consistent format described in Section 4 of [RFC6564] 331 MUST be followed. 333 5.3. Protecting a node from excessive EH options 335 Per RFC 8200, end hosts are expected to process all extension 336 headers, destination options, and hop-by-hop options in a packet. 337 Given that the only limit on the number and size of extension headers 338 is the MTU, the processing of received packets could be considerable. 339 It is also conceivable that a long chain of extension headers might 340 be used as a form of denial-of-service attack. Accordingly, a host 341 may place limits on the number and sizes of extension headers and 342 options it is willing to process. 344 A host MAY limit the number of consecutive PAD1 options in 345 destination options or hop-by-hop options to seven. In this case, if 346 the more than seven consecutive PAD1 options are present the packet 347 should be silently discarded. The rationale is that if padding of 348 eight or more bytes is required than the PADN option should be used. 350 A host MAY limit number of bytes in a PADN option to be less than 351 eight. In such a case, if a PADN option is present that has a length 352 greater than seven then the packet should be silently discarded. The 353 rationale for this guideline is that the purpose of padding is for 354 alignment and eight bytes is the maximum alignment used in IPv6. 356 A host MAY disallow unknown options in destination options or hop-by- 357 hop options. This should be configurable where the default is to 358 accept unknown options and process them per [RFC8200]. If a packet 359 with unknown options is received and the host is configured to 360 disallow them, then the packet should be silently discarded. 362 A host MAY impose a limit on the maximum number of non-padding 363 options allowed in a destination options and hop-by-hop extension 364 headers. If this feature is supported the maximum number should be 365 configurable and the default value SHOULD be set to eight. The 366 limits for destination options and hop-by-hop options may be 367 separately configurable. If a packet is received and the number of 368 destination or hop-by-hop optines exceeds the limit, then the packet 369 should be silently discarded. 371 A host MAY impose a limit on the maximum length of destination 372 options or hop-by-hop options extension header. This value should be 373 configurable and the default is to accept options of any length. If 374 a packet is received and the length of destination or hop-by-hop 375 options extension header exceeds the length limit, then the packet 376 should be silently discarded. 378 5.4. Neighbor Discovery for IPv6 - RFC 4861 380 Neighbor Discovery is defined in [RFC4861]; the definition was 381 updated by [RFC5942]. Neighbor Discovery SHOULD be supported. RFC 382 4861 states: 384 Unless specified otherwise (in a document that covers operating IP 385 over a particular link type) this document applies to all link 386 types. However, because ND uses link-layer multicast for some of 387 its services, it is possible that on some link types (e.g., Non- 388 Broadcast Multi-Access (NBMA) links), alternative protocols or 389 mechanisms to implement those services will be specified (in the 390 appropriate document covering the operation of IP over a 391 particular link type). The services described in this document 392 that are not directly dependent on multicast, such as Redirects, 393 next-hop determination, Neighbor Unreachability Detection, etc., 394 are expected to be provided as specified in this document. The 395 details of how one uses ND on NBMA links are addressed in 396 [RFC2491]. 398 Some detailed analysis of Neighbor Discovery follows: 400 Router Discovery is how hosts locate routers that reside on an 401 attached link. Hosts MUST support Router Discovery functionality. 403 Prefix Discovery is how hosts discover the set of address prefixes 404 that define which destinations are on-link for an attached link. 405 Hosts MUST support Prefix Discovery. 407 Hosts MUST also implement Neighbor Unreachability Detection (NUD) for 408 all paths between hosts and neighboring nodes. NUD is not required 409 for paths between routers. However, all nodes MUST respond to 410 unicast Neighbor Solicitation (NS) messages. 412 [RFC7048] discusses NUD, in particular cases where it behaves too 413 impatiently. It states that if a node transmits more than a certain 414 number of packets, then it SHOULD use the exponential backoff of the 415 retransmit timer, up to a certain threshold point. 417 Hosts MUST support the sending of Router Solicitations and the 418 receiving of Router Advertisements. The ability to understand 419 individual Router Advertisement options is dependent on supporting 420 the functionality making use of the particular option. 422 [RFC7559] discusses packet loss resliency for Router Solicitations, 423 and requires that nodes MUST use a specific exponential backoff 424 algorithm for RS retransmissions. 426 All nodes MUST support the sending and receiving of Neighbor 427 Solicitation (NS) and Neighbor Advertisement (NA) messages. NS and 428 NA messages are required for Duplicate Address Detection (DAD). 430 Hosts SHOULD support the processing of Redirect functionality. 431 Routers MUST support the sending of Redirects, though not necessarily 432 for every individual packet (e.g., due to rate limiting). Redirects 433 are only useful on networks supporting hosts. In core networks 434 dominated by routers, Redirects are typically disabled. The sending 435 of Redirects SHOULD be disabled by default on backbone routers. They 436 MAY be enabled by default on routers intended to support hosts on 437 edge networks. 439 "IPv6 Host-to-Router Load Sharing" [RFC4311] includes additional 440 recommendations on how to select from a set of available routers. 441 [RFC4311] SHOULD be supported. 443 5.5. SEcure Neighbor Discovery (SEND) - RFC 3971 445 SEND [RFC3971] and Cryptographically Generated Addresses (CGAs) 446 [RFC3972] provide a way to secure the message exchanges of Neighbor 447 Discovery. SEND has the potential to address certain classes of 448 spoofing attacks, but it does not provide specific protection for 449 threats from off-link attackers. 451 There have been relatively few implementations of SEND in common 452 operating systems and platforms, and thus deployment experience has 453 been limited to date. 455 At this time, SEND is considered optional. Due to the complexity in 456 deploying SEND, and its heavyweight provisioning, its deployment is 457 only likely to be considered where nodes are operating in a 458 particularly strict security environment. 460 5.6. IPv6 Router Advertisement Flags Option - RFC 5175 462 Router Advertisements include an 8-bit field of single-bit Router 463 Advertisement flags. The Router Advertisement Flags Option extends 464 the number of available flag bits by 48 bits. At the time of this 465 writing, 6 of the original 8 single-bit flags have been assigned, 466 while 2 remain available for future assignment. No flags have been 467 defined that make use of the new option, and thus, strictly speaking, 468 there is no requirement to implement the option today. However, 469 implementations that are able to pass unrecognized options to a 470 higher-level entity that may be able to understand them (e.g., a 471 user-level process using a "raw socket" facility) MAY take steps to 472 handle the option in anticipation of a future usage. 474 5.7. Path MTU Discovery and Packet Size 476 5.7.1. Path MTU Discovery - RFC 8201 478 "Path MTU Discovery for IP version 6" [RFC8201] SHOULD be supported. 479 From [RFC8200]: 481 It is strongly recommended that IPv6 nodes implement Path MTU 482 Discovery [RFC8201], in order to discover and take advantage of 483 path MTUs greater than 1280 octets. However, a minimal IPv6 484 implementation (e.g., in a boot ROM) may simply restrict itself to 485 sending packets no larger than 1280 octets, and omit 486 implementation of Path MTU Discovery. 488 The rules in [RFC8200] and [RFC5722] MUST be followed for packet 489 fragmentation and reassembly. 491 One operational issue with Path MTU Discovery occurs when, contrary 492 to the guidance in [RFC4890], firewalls block ICMP Packet Too Big 493 messages. Path MTU Discovery relies on such messages to determine 494 what size messages can be successfully sent. "Packetization Layer 495 Path MTU Discovery" [RFC4821] avoids having a dependency on Packet 496 Too Big messages. 498 5.7.2. Minimum MTU considerations 500 While an IPv6 link MTU can be set to 1280 bytes, it is recommended 501 that for IPv6 UDP in particular, which includes DNS operation, the 502 sender use a large MTU if they can, in order to avoid gratuitous 503 fragmentation-caused packet drops. 505 5.8. ICMP for the Internet Protocol Version 6 (IPv6) - RFC 4443 507 ICMPv6 [RFC4443] MUST be supported. "Extended ICMP to Support Multi- 508 Part Messages" [RFC4884] MAY be supported. 510 5.9. Default Router Preferences and More-Specific Routes - RFC 4191 512 "Default Router Preferences and More-Specific Routes" [RFC4191] 513 provides support for nodes attached to multiple (different) networks, 514 each providing routers that advertise themselves as default routers 515 via Router Advertisements. In some scenarios, one router may provide 516 connectivity to destinations the other router does not, and choosing 517 the "wrong" default router can result in reachability failures. In 518 order to resolve this scenario IPv6 Nodes MUST implement [RFC4191] 519 and SHOULD implement the Type C host role defined in RFC4191. 521 5.10. First-Hop Router Selection - RFC 8028 523 In multihomed scenarios, where a host has more than one prefix, each 524 allocated by an upstream network that is assumed to implement BCP 38 525 ingress filtering, the host may have multiple routers to choose from. 527 Hosts that may be deployed in such multihomed environments SHOULD 528 follow the guidance given in [RFC8028]. 530 5.11. Multicast Listener Discovery (MLD) for IPv6 - RFC 3810 532 Nodes that need to join multicast groups MUST support MLDv2 533 [RFC3810]. MLD is needed by any node that is expected to receive and 534 process multicast traffic and in particular MLDv2 is required for 535 support for source-specific multicast (SSM) as per [RFC4607]. 537 Previous versions of this document only required MLDv1 ([RFC2710]) to 538 be implemented on all nodes. Since participation of any MLDv1-only 539 nodes on a link require that all other nodeas on the link then 540 operate in version 1 compatibility mode, the requirement to support 541 MLDv2 on all nodes was upgraded to a MUST. Further, SSM is now the 542 preferred multicast distribution method, rather than ASM. 544 Note that Neighbor Discovery (as used on most link types -- see 545 Section 5.4) depends on multicast and requires that nodes join 546 Solicited Node multicast addresses. 548 5.12. Explicit Congestion Notification (ECN) - RFC 3168 550 An ECN-aware router may set a mark in the IP header in order to 551 signal impending congestion, rather than dropping a packet. The 552 receiver of the packet echoes the congestion indication to the 553 sender, which can then reduce its transmission rate as if it detected 554 a dropped packet. 556 Nodes that may be deployed in environments where they would benefit 557 from such early congestion notification SHOULD implement [RFC3168]. 558 In such cases, the updates presented in [RFC8311] may also be 559 relevant. 561 6. Addressing and Address Configuration 563 6.1. IP Version 6 Addressing Architecture - RFC 4291 565 The IPv6 Addressing Architecture [RFC4291] MUST be supported. 567 The current IPv6 Address Architecture is based on a 64-bit boundary 568 for subnet prefixes. The reasoning behind this decision is 569 documented in [RFC7421]. 571 Implementations MUST also support the Multicast flag updates 572 documented in [RFC7371] 574 6.2. Host Address Availability Recommendations 576 Hosts may be configured with addresses through a variety of methods, 577 including SLAAC, DHCPv6, or manual configuration. 579 [RFC7934] recommends that networks provide general-purpose end hosts 580 with multiple global IPv6 addresses when they attach, and it 581 describes the benefits of and the options for doing so. Routers 582 SHOULD support [RFC7934] for assigning multiple address to a host. 583 Host SHOULD support assigning multiple addresses as described in 584 [RFC7934]. 586 Nodes SHOULD support the capability to be assigned a prefix per host 587 as documented in [RFC8273]. Such an approach can offer improved host 588 isolation and enhanced subscriber management on shared network 589 segments. 591 6.3. IPv6 Stateless Address Autoconfiguration - RFC 4862 593 Hosts MUST support IPv6 Stateless Address Autoconfiguration. It is 594 recommended, as described in [RFC8064], that unless there is a 595 specific requirement for MAC addresses to be embedded in an IID, 596 nodes follow the procedure in [RFC7217] to generate SLAAC-based 597 addresses, rather than using [RFC4862]. Addresses generated through 598 RFC7217 will be the same whenever a given device (re)appears on the 599 same subnet (with a specific IPv6 prefix), but the IID will vary on 600 each subnet visited. 602 Nodes that are routers MUST be able to generate link-local addresses 603 as described in [RFC4862]. 605 From RFC 4862: 607 The autoconfiguration process specified in this document applies 608 only to hosts and not routers. Since host autoconfiguration uses 609 information advertised by routers, routers will need to be 610 configured by some other means. However, it is expected that 611 routers will generate link-local addresses using the mechanism 612 described in this document. In addition, routers are expected to 613 successfully pass the Duplicate Address Detection procedure 614 described in this document on all addresses prior to assigning 615 them to an interface. 617 All nodes MUST implement Duplicate Address Detection. Quoting from 618 Section 5.4 of RFC 4862: 620 Duplicate Address Detection MUST be performed on all unicast 621 addresses prior to assigning them to an interface, regardless of 622 whether they are obtained through stateless autoconfiguration, 623 DHCPv6, or manual configuration, with the following [exceptions 624 noted therein]. 626 "Optimistic Duplicate Address Detection (DAD) for IPv6" [RFC4429] 627 specifies a mechanism to reduce delays associated with generating 628 addresses via Stateless Address Autoconfiguration [RFC4862]. RFC 629 4429 was developed in conjunction with Mobile IPv6 in order to reduce 630 the time needed to acquire and configure addresses as devices quickly 631 move from one network to another, and it is desirable to minimize 632 transition delays. For general purpose devices, RFC 4429 remains 633 optional at this time. 635 [RFC7527] discusses enhanced DAD, and describes an algorithm to 636 automate the detection of looped back IPv6 ND messages used by DAD. 637 Nodes SHOULD implement this behaviour where such detection is 638 beneficial. 640 6.4. Privacy Extensions for Address Configuration in IPv6 - RFC 4941 642 A node using Stateless Address Autoconfiguration [RFC4862] to form a 643 globally unique IPv6 address using its MAC address to generate the 644 IID will see that IID remain the same on any visited network, even 645 though the network prefix part changes. Thus it is possible for 3rd 646 party devices such nodes communicate with to track the activities of 647 the node as it moves around the network. Privacy Extensions for 648 Stateless Address Autoconfiguration [RFC4941] address this concern by 649 allowing nodes to configure an additional temporary address where the 650 IID is effectively randomly generated. Privacy addresses are then 651 used as source addresses for new communications initiated by the 652 node. 654 General issues regarding privacy issues for IPv6 addressing are 655 discussed in [RFC7721]. 657 RFC 4941 SHOULD be supported. In some scenarios, such as dedicated 658 servers in a data center, it provides limited or no benefit, or may 659 complicate network management. Thus devices implementing this 660 specification MUST provide a way for the end user to explicitly 661 enable or disable the use of such temporary addresses. 663 Note that RFC4941 can be used independently of traditional SLAAC, or 664 of RFC7217-based SLAAC. 666 Implementers of RFC 4941 should be aware that certain addresses are 667 reserved and should not be chosen for use as temporary addresses. 668 Consult "Reserved IPv6 Interface Identifiers" [RFC5453] for more 669 details. 671 6.5. Stateful Address Autoconfiguration (DHCPv6) - RFC 3315 673 DHCPv6 [RFC3315] can be used to obtain and configure addresses. In 674 general, a network may provide for the configuration of addresses 675 through SLAAC, DHCPv6, or both. There will be a wide range of IPv6 676 deployment models and differences in address assignment requirements, 677 some of which may require DHCPv6 for stateful address assignment. 678 Consequently, all hosts SHOULD implement address configuration via 679 DHCPv6. 681 In the absence of observed Router Advertisement messages, IPv6 nodes 682 MAY initiate DHCP to obtain IPv6 addresses and other configuration 683 information, as described in Section 5.5.2 of [RFC4862]. 685 Where devices are likely to be carried by users and attached to 686 multiple visisted networks, DHCPv6 client anonymity profiles SHOULD 687 be supported as described in [RFC7844] to minimise the disclosure of 688 identifying information. Section 5 of RFC7844 describes operational 689 considerations on the use of such anonymity profiles. 691 6.6. Default Address Selection for IPv6 - RFC 6724 693 IPv6 nodes will invariably have multiple addresses configured 694 simultaneously, and thus will need to choose which addresses to use 695 for which communications. The rules specified in the Default Address 696 Selection for IPv6 [RFC6724] document MUST be implemented. [RFC8028] 697 updates rule 5.5 from [RFC6724]; implementations SHOULD implement 698 this rule. 700 7. DNS 702 DNS is described in [RFC1034], [RFC1035], [RFC3363], and [RFC3596]. 703 Not all nodes will need to resolve names; those that will never need 704 to resolve DNS names do not need to implement resolver functionality. 705 However, the ability to resolve names is a basic infrastructure 706 capability on which applications rely, and most nodes will need to 707 provide support. All nodes SHOULD implement stub-resolver [RFC1034] 708 functionality, as in [RFC1034], Section 5.3.1, with support for: 710 - AAAA type Resource Records [RFC3596]; 711 - reverse addressing in ip6.arpa using PTR records [RFC3596]; 713 - Extension Mechanisms for DNS (EDNS0) [RFC6891] to allow for DNS 714 packet sizes larger than 512 octets. 716 Those nodes are RECOMMENDED to support DNS security extensions 717 [RFC4033] [RFC4034] [RFC4035]. 719 A6 Resource Records, which were only ever defined with Experimental 720 status in [RFC3363], are now classified as Historic, as per 721 [RFC6563]. 723 8. Configuring Non-Address Information 725 8.1. DHCP for Other Configuration Information 727 DHCP [RFC3315] Specifies a mechanism for IPv6 nodes to obtain address 728 configuration information (see Section 6.5) and to obtain additional 729 (non-address) configuration. If a host implementation supports 730 applications or other protocols that require configuration that is 731 only available via DHCP, hosts SHOULD implement DHCP. For 732 specialized devices on which no such configuration need is present, 733 DHCP may not be necessary. 735 An IPv6 node can use the subset of DHCP (described in [RFC3736]) to 736 obtain other configuration information. 738 If an IPv6 node implements DHCP it MUST implement the DNS options 739 [RFC3646] as most deployments will expect this options are 740 available. 742 8.2. Router Advertisements and Default Gateway 744 There is no defined DHCPv6 Gateway option. 746 Nodes using the Dynamic Host Configuration Protocol for IPv6 (DHCPv6) 747 are thus expected to determine their default router information and 748 on-link prefix information from received Router Advertisements. 750 8.3. IPv6 Router Advertisement Options for DNS Configuration - RFC 8106 752 Router Advertisement Options have historically been limited to those 753 that are critical to basic IPv6 functionality. Originally, DNS 754 configuration was not included as an RA option, and DHCP was the 755 recommended way to obtain DNS configuration information. Over time, 756 the thinking surrounding such an option has evolved. It is now 757 generally recognized that few nodes can function adequately without 758 having access to a working DNS resolver, and thus a Standards Track 759 document has been published to provide this capability [RFC8106]. 761 Implementations MUST include support for the DNS RA option [RFC8106]. 763 8.4. DHCP Options versus Router Advertisement Options for Host 764 Configuration 766 In IPv6, there are two main protocol mechanisms for propagating 767 configuration information to hosts: Router Advertisements (RAs) and 768 DHCP. RA options have been restricted to those deemed essential for 769 basic network functioning and for which all nodes are configured with 770 exactly the same information. Examples include the Prefix 771 Information Options, the MTU option, etc. On the other hand, DHCP 772 has generally been preferred for configuration of more general 773 parameters and for parameters that may be client-specific. Generally 774 speaking, however, there has been a desire to define only one 775 mechanism for configuring a given option, rather than defining 776 multiple (different) ways of configuring the same information. 778 One issue with having multiple ways of configuring the same 779 information is that interoperability suffers if a host chooses one 780 mechanism but the network operator chooses a different mechanism. 781 For "closed" environments, where the network operator has significant 782 influence over what devices connect to the network and thus what 783 configuration mechanisms they support, the operator may be able to 784 ensure that a particular mechanism is supported by all connected 785 hosts. In more open environments, however, where arbitrary devices 786 may connect (e.g., a WIFI hotspot), problems can arise. To maximize 787 interoperability in such environments, hosts would need to implement 788 multiple configuration mechanisms to ensure interoperability. 790 9. Service Discovery Protocols 792 [RFC6762] and [RFC6763] describe multicast DNS (mDNS) and DNS-Based 793 Service Discovery (DNS-SD) respectively. These protocols, 794 collectively commonly referred to as the 'Bonjour' protocols after 795 their naming by Apple, provide the means for devices to discover 796 services within a local link and, in the absence of a unicast DNS 797 service, to exchange naming information. 799 Where devices are to be deployed in networks where service dicovery 800 would be beneficial, e.g., for users seeking to discover printers or 801 display devices, mDNS and DNS-SD SHOULD be supported. 803 The IETF dnssd WG is defining solutions for DNS-based service 804 discovery in multi-link networks. 806 10. IPv4 Support and Transition 808 IPv6 nodes MAY support IPv4. 810 10.1. Transition Mechanisms 812 10.1.1. Basic Transition Mechanisms for IPv6 Hosts and Routers - RFC 813 4213 815 If an IPv6 node implements dual stack and tunneling, then [RFC4213] 816 MUST be supported. 818 11. Application Support 820 11.1. Textual Representation of IPv6 Addresses - RFC 5952 822 Software that allows users and operators to input IPv6 addresses in 823 text form SHOULD support "A Recommendation for IPv6 Address Text 824 Representation" [RFC5952]. 826 11.2. Application Programming Interfaces (APIs) 828 There are a number of IPv6-related APIs. This document does not 829 mandate the use of any, because the choice of API does not directly 830 relate to on-the-wire behavior of protocols. Implementers, however, 831 would be advised to consider providing a common API or reviewing 832 existing APIs for the type of functionality they provide to 833 applications. 835 "Basic Socket Interface Extensions for IPv6" [RFC3493] provides IPv6 836 functionality used by typical applications. Implementers should note 837 that RFC3493 has been picked up and further standardized by the 838 Portable Operating System Interface (POSIX) [POSIX]. 840 "Advanced Sockets Application Program Interface (API) for IPv6" 841 [RFC3542] provides access to advanced IPv6 features needed by 842 diagnostic and other more specialized applications. 844 "IPv6 Socket API for Source Address Selection" [RFC5014] provides 845 facilities that allow an application to override the default Source 846 Address Selection rules of [RFC6724]. 848 "Socket Interface Extensions for Multicast Source Filters" [RFC3678] 849 provides support for expressing source filters on multicast group 850 memberships. 852 "Extension to Sockets API for Mobile IPv6" [RFC4584] provides 853 application support for accessing and enabling Mobile IPv6 [RFC6275] 854 features. 856 12. Mobility 858 Mobile IPv6 [RFC6275] and associated specifications [RFC3776] 859 [RFC4877] allow a node to change its point of attachment within the 860 Internet, while maintaining (and using) a permanent address. All 861 communication using the permanent address continues to proceed as 862 expected even as the node moves around. The definition of Mobile IP 863 includes requirements for the following types of nodes: 865 - mobile nodes 867 - correspondent nodes with support for route optimization 869 - home agents 871 - all IPv6 routers 873 At the present time, Mobile IP has seen only limited implementation 874 and no significant deployment, partly because it originally assumed 875 an IPv6-only environment rather than a mixed IPv4/IPv6 Internet. 876 Recently, additional work has been done to support mobility in mixed- 877 mode IPv4 and IPv6 networks [RFC5555]. 879 More usage and deployment experience is needed with mobility before 880 any specific approach can be recommended for broad implementation in 881 all hosts and routers. Consequently, [RFC6275], [RFC5555], and 882 associated standards such as [RFC4877] are considered a MAY at this 883 time. 885 IPv6 for 3GPP [RFC7066] lists a snapshot of required IPv6 886 Functionalities at the time the document was published that would 887 need to be implemented, going above and beyond the recommendations in 888 this document. Additionally a 3GPP IPv6 Host MAY implement [RFC7278] 889 for delivering IPv6 prefixes on the LAN link. 891 13. Security 893 This section describes the specification for security for IPv6 nodes. 895 Achieving security in practice is a complex undertaking. Operational 896 procedures, protocols, key distribution mechanisms, certificate 897 management approaches, etc., are all components that impact the level 898 of security actually achieved in practice. More importantly, 899 deficiencies or a poor fit in any one individual component can 900 significantly reduce the overall effectiveness of a particular 901 security approach. 903 IPsec either can provide end-to-end security between nodes or or can 904 provide channel security (for example, via a site-to-site IPsec VPN), 905 making it possible to provide secure communication for all (or a 906 subset of) communication flows at the IP layer between pairs of 907 internet nodes. IPsec has two standard operating modes, Tunnel-mode 908 and Transport-mode. In Tunnel-mode, IPsec provides network-layer 909 security and protects an entire IP packet by encapsulating the 910 orginal IP packet and then pre-pending a new IP header. In 911 Transport-mode, IPsec provides security for the transport-layer (and 912 above) by encapsulating only the transport-layer (and above) portion 913 of the IP packet (i.e., without adding a 2nd IP header). 915 Although IPsec can be used with manual keying in some cases, such 916 usage has limited applicability and is not recommended. 918 A range of security technologies and approaches proliferate today 919 (e.g., IPsec, Transport Layer Security (TLS), Secure SHell (SSH), SSL 920 VPNS, etc.) No one approach has emerged as an ideal technology for 921 all needs and environments. Moreover, IPsec is not viewed as the 922 ideal security technology in all cases and is unlikely to displace 923 the others. 925 Previously, IPv6 mandated implementation of IPsec and recommended the 926 key management approach of IKE. This document updates that 927 recommendation by making support of the IPsec Architecture [RFC4301] 928 a SHOULD for all IPv6 nodes. Note that the IPsec Architecture 929 requires (e.g., Section 4.5 of RFC 4301) the implementation of both 930 manual and automatic key management. Currently, the default 931 automated key management protocol to implement is IKEv2 [RFC7296]. 933 This document recognizes that there exists a range of device types 934 and environments where approaches to security other than IPsec can be 935 justified. For example, special-purpose devices may support only a 936 very limited number or type of applications, and an application- 937 specific security approach may be sufficient for limited management 938 or configuration capabilities. Alternatively, some devices may run 939 on extremely constrained hardware (e.g., sensors) where the full 940 IPsec Architecture is not justified. 942 Because most common platforms now support IPv6 and have it enabled by 943 default, IPv6 security is an issue for networks that are ostensibly 944 IPv4-only; see [RFC7123] for guidance on this area. 946 13.1. Requirements 948 "Security Architecture for the Internet Protocol" [RFC4301] SHOULD be 949 supported by all IPv6 nodes. Note that the IPsec Architecture 950 requires (e.g., Section 4.5 of [RFC4301]) the implementation of both 951 manual and automatic key management. Currently, the default 952 automated key management protocol to implement is IKEv2. As required 953 in [RFC4301], IPv6 nodes implementing the IPsec Architecture MUST 954 implement ESP [RFC4303] and MAY implement AH [RFC4302]. 956 13.2. Transforms and Algorithms 958 The current set of mandatory-to-implement algorithms for the IPsec 959 Architecture are defined in "Cryptographic Algorithm Implementation 960 Requirements For ESP and AH" [RFC8221]. IPv6 nodes implementing the 961 IPsec Architecture MUST conform to the requirements in [RFC8221]. 962 Preferred cryptographic algorithms often change more frequently than 963 security protocols. Therefore, implementations MUST allow for 964 migration to new algorithms, as RFC 8221 is replaced or updated in 965 the future. 967 The current set of mandatory-to-implement algorithms for IKEv2 are 968 defined in "Cryptographic Algorithms for Use in the Internet Key 969 Exchange Version 2 (IKEv2)" [RFC8247]. IPv6 nodes implementing IKEv2 970 MUST conform to the requirements in [RFC8247] and/or any future 971 updates or replacements to [RFC8247]. 973 14. Router-Specific Functionality 975 This section defines general host considerations for IPv6 nodes that 976 act as routers. Currently, this section does not discuss detailed 977 routing-specific requirements. For the case of typical home routers, 978 [RFC7084] defines basic requirements for customer edge routers. 980 Further recommendations on router-specific functionality can be found 981 in [I-D.ietf-v6ops-ipv6rtr-reqs]. 983 14.1. IPv6 Router Alert Option - RFC 2711 985 The IPv6 Router Alert Option [RFC2711] is an optional IPv6 Hop-by-Hop 986 Header that is used in conjunction with some protocols (e.g., RSVP 987 [RFC2205] or Multicast Listener Discovery (MLDv2) [RFC3810]). The 988 Router Alert option will need to be implemented whenever such 989 protocols that mandate its use are implemented. See Section 5.11. 991 14.2. Neighbor Discovery for IPv6 - RFC 4861 993 Sending Router Advertisements and processing Router Solicitations 994 MUST be supported. 996 Section 7 of [RFC6275] includes some mobility-specific extensions to 997 Neighbor Discovery. Routers SHOULD implement Sections 7.3 and 7.5, 998 even if they do not implement Home Agent functionality. 1000 14.3. Stateful Address Autoconfiguration (DHCPv6) - RFC 3315 1002 A single DHCP server ([RFC3315] or [RFC4862]) can provide 1003 configuration information to devices directly attached to a shared 1004 link, as well as to devices located elsewhere within a site. 1005 Communication between a client and a DHCP server located on different 1006 links requires the use of DHCP relay agents on routers. 1008 In simple deployments, consisting of a single router and either a 1009 single LAN or multiple LANs attached to the single router, together 1010 with a WAN connection, a DHCP server embedded within the router is 1011 one common deployment scenario (e.g., [RFC7084]). There is no need 1012 for relay agents in such scenarios. 1014 In more complex deployment scenarios, such as within enterprise or 1015 service provider networks, the use of DHCP requires some level of 1016 configuration, in order to configure relay agents, DHCP servers, etc. 1017 In such environments, the DHCP server might even be run on a 1018 traditional server, rather than as part of a router. 1020 Because of the wide range of deployment scenarios, support for DHCP 1021 server functionality on routers is optional. However, routers 1022 targeted for deployment within more complex scenarios (as described 1023 above) SHOULD support relay agent functionality. Note that "Basic 1024 Requirements for IPv6 Customer Edge Routers" [RFC7084] requires 1025 implementation of a DHCPv6 server function in IPv6 Customer Edge (CE) 1026 routers. 1028 14.4. IPv6 Prefix Length Recommendation for Forwarding - BCP 198 1030 Forwarding nodes MUST conform to BCP 198 [RFC7608] and thus IPv6 1031 implementations of nodes that may forward packets MUST conform to the 1032 rules specified in Section 5.1 of [RFC4632]. 1034 15. Constrained Devices 1036 The target for this document is general IPv6 nodes. In the case of 1037 constrained nodes, with limited CPU, memory, bandwidth or power, 1038 support for certain IPv6 functionality may need to be considered due 1039 to those limitations. The requirements of this document are 1040 RECOMMENDED for all nodes, including constrained nodes, but 1041 compromises may need to be made in certain cases. Where such 1042 compromises are made, the interoperability of devices should be 1043 strongly considered, paticularly where this may impact other nodes on 1044 the same link, e.g., only supporting MLDv1 will affect other nodes. 1046 The IETF 6LowPAN (IPv6 over Low Power LWPAN) WG defined six RFCs, 1047 including a general overview and problem statement ([RFC4919], the 1048 means by which IPv6 packets are transmitted over IEEE 802.15.4 1049 networks [RFC4944] and ND optimisations for that medium [RFC6775]. 1051 If an IPv6 node is concerned about the impact of IPv6 message power 1052 consumption, it SHOULD want to implement the recommendations in 1053 [RFC7772]. 1055 16. Network Management 1057 Network management MAY be supported by IPv6 nodes. However, for IPv6 1058 nodes that are embedded devices, network management may be the only 1059 possible way of controlling these nodes. 1061 Existing network management protocols include SNMP [RFC3411], NETCONF 1062 [RFC6241] and RESTCONF [RFC8040]. 1064 16.1. Management Information Base (MIB) Modules 1066 IPv6 MIBs have been updated since the last release of the document; 1067 [RFC8096] obseletes several MIBs, which nodes need no longer 1068 support. 1070 The following two MIB modules SHOULD be supported by nodes that 1071 support a Simple Network Management Protocol (SNMP) agent. 1073 16.1.1. IP Forwarding Table MIB 1075 The IP Forwarding Table MIB [RFC4292] SHOULD be supported by nodes 1076 that support an SNMP agent. 1078 16.1.2. Management Information Base for the Internet Protocol (IP) 1080 The IP MIB [RFC4293] SHOULD be supported by nodes that support an 1081 SNMP agent. 1083 16.1.3. Interface MIB 1085 The Interface MIB [RFC2863] SHOULD be supported by nodes the support 1086 an SNMP agent. 1088 16.2. YANG Data Models 1090 The following YANG data models SHOULD be supported by nodes that 1091 support a NETCONF agent. 1093 16.2.1. IP Management YANG Model 1095 The IP Management YANG Model [RFC7277] SHOULD be supported by nodes 1096 that support NETCONF. 1098 16.2.2. Interface Management YANG Model 1100 The Interface Management YANG Model [RFC7223] SHOULD be supported by 1101 nodes that support NETCONF. 1103 17. Security Considerations 1105 This document does not directly affect the security of the Internet, 1106 beyond the security considerations associated with the individual 1107 protocols. 1109 Security is also discussed in Section 13 above. 1111 18. IANA Considerations 1113 This document does not require any IANA actions. 1115 19. Authors and Acknowledgments 1117 19.1. Authors and Acknowledgments (Current Document) 1119 For this version of the IPv6 Node Requirements document, the authors 1120 would like to thank Brian Carpenter, Dave Thaler, Tom Herbert, Erik 1121 Kline, Mohamed Boucadair, and Michayla Newcombe for their 1122 contributions. 1124 19.2. Authors and Acknowledgments from RFC 6434 1126 Ed Jankiewicz and Thomas Narten were named authors of the previous 1127 iteration of this document, RFC6434. 1129 For this version of the document, the authors thanked Hitoshi Asaeda, 1130 Brian Carpenter, Tim Chown, Ralph Droms, Sheila Frankel, Sam Hartman, 1131 Bob Hinden, Paul Hoffman, Pekka Savola, Yaron Sheffer, and Dave 1132 Thaler. 1134 19.3. Authors and Acknowledgments from RFC 4294 1136 The original version of this document (RFC 4294) was written by the 1137 IPv6 Node Requirements design team: 1139 Jari Arkko 1140 jari.arkko@ericsson.com 1142 Marc Blanchet 1143 marc.blanchet@viagenie.qc.ca 1145 Samita Chakrabarti 1146 samita.chakrabarti@eng.sun.com 1148 Alain Durand 1149 alain.durand@sun.com 1151 Gerard Gastaud 1152 gerard.gastaud@alcatel.fr 1154 Jun-ichiro Itojun Hagino 1155 itojun@iijlab.net 1157 Atsushi Inoue 1158 inoue@isl.rdc.toshiba.co.jp 1160 Masahiro Ishiyama 1161 masahiro@isl.rdc.toshiba.co.jp 1163 John Loughney 1164 john.loughney@nokia.com 1166 Rajiv Raghunarayan 1167 raraghun@cisco.com 1168 Shoichi Sakane 1169 shouichi.sakane@jp.yokogawa.com 1171 Dave Thaler 1172 dthaler@windows.microsoft.com 1174 Juha Wiljakka 1175 juha.wiljakka@Nokia.com 1177 The authors would like to thank Ran Atkinson, Jim Bound, Brian 1178 Carpenter, Ralph Droms, Christian Huitema, Adam Machalek, Thomas 1179 Narten, Juha Ollila, and Pekka Savola for their comments. Thanks to 1180 Mark Andrews for comments and corrections on DNS text. Thanks to 1181 Alfred Hoenes for tracking the updates to various RFCs. 1183 20. Appendix: Changes from RFC 6434 1185 There have been many editorial clarifications as well as significant 1186 additions and updates. While this section highlights some of the 1187 changes, readers should not rely on this section for a comprehensive 1188 list of all changes. 1190 1. Restructured sections 1192 2. Added 6LoWPAN to link layers as it has some deployment. 1194 3. Removed DOD IPv6 Profile as it hasn't been updated. 1196 4. Updated to MLDv2 support to a MUST since nodes are restricted if 1197 MLDv1 is used. 1199 5. Require DNS RA Options so SLAAC-only devices can get DNS, 1200 RFC8106 is a MUST. 1202 6. Require RFC3646 DNS Options for DHCPv6 implementations. 1204 7. Added RESTCONF and NETCONF as possible options to Network 1205 management. 1207 8. Added section on constrained devices. 1209 9. Added text on RFC7934, address availability to hosts (SHOULD). 1211 10. Added text on RFC7844, anonymity profiles for DHCPv6 clients. 1213 11. mDNS and DNS-SD added as updated service discovery. 1215 12. Added RFC8028 as a SHOULD as a method for solving multi-prefix 1216 network 1218 13. Added ECN RFC3168 as a SHOULD, since recent reports have shown 1219 this as useful, and added a note on RFC8311, which is related. 1221 14. Added reference to RFC7123 for Security over IPv4-only networks 1223 15. Removed Jumbograms RFC2675 as they aren't deployed. 1225 16. Updated Obseleted RFCs to the new version of the RFC including 1226 2460, 1981, 7321, 4307 1228 17. Added RFC7772 for power comsumptions considerations 1230 18. Added why /64 boundries for more detail - RFC 7421 1232 19. Added a Unique IPv6 Prefix per Host to support currently 1233 deployed IPv6 networks 1235 20. Clarified RFC7066 was snapshot for 3GPP 1237 21. Updated 4191 as a MUST, SHOULD for Type C Host as it helps solve 1238 multi-prefix problem 1240 22. Removed IPv6 over ATM since there aren't many deployments 1242 23. Added a note in Section 6.6 for RFC6724 Section 5.5/ 1244 24. Added MUST for BCP 198 for forwarding IPv6 packets 1246 25. Added reference to draft-ietf-v6ops-ipv6rtr-reqs as it has more 1247 recommendations for a Router 1249 26. Added reference to RFC8064 for stable address creation. 1251 27. Added text on protection from excessive EH options 1253 28. Added text on dangers of 1280 MTU UDP, esp. wrt DNS traffic 1255 29. Added text to clarify RFC8200 behaviour for unrecognized EHs or 1256 unrecognized ULPs 1258 21. Appendix: Changes from RFC 4294 1260 There have been many editorial clarifications as well as significant 1261 additions and updates. While this section highlights some of the 1262 changes, readers should not rely on this section for a comprehensive 1263 list of all changes. 1265 1. Updated the Introduction to indicate that this document is an 1266 applicability statement and is aimed at general nodes. 1268 2. Significantly updated the section on Mobility protocols, adding 1269 references and downgrading previous SHOULDs to MAYs. 1271 3. Changed Sub-IP Layer section to just list relevant RFCs, and 1272 added some more RFCs. 1274 4. Added section on SEND (it is a MAY). 1276 5. Revised section on Privacy Extensions [RFC4941] to add more 1277 nuance to recommendation. 1279 6. Completely revised IPsec/IKEv2 section, downgrading overall 1280 recommendation to a SHOULD. 1282 7. Upgraded recommendation of DHCPv6 to SHOULD. 1284 8. Added background section on DHCP versus RA options, added SHOULD 1285 recommendation for DNS configuration via RAs (RFC6106), and 1286 cleaned up DHCP recommendations. 1288 9. Added recommendation that routers implement Sections 7.3 and 7.5 1289 of [RFC6275]. 1291 10. Added pointer to subnet clarification document [RFC5942]. 1293 11. Added text that "IPv6 Host-to-Router Load Sharing" [RFC4311] 1294 SHOULD be implemented. 1296 12. Added reference to [RFC5722] (Overlapping Fragments), and made 1297 it a MUST to implement. 1299 13. Made "A Recommendation for IPv6 Address Text Representation" 1300 [RFC5952] a SHOULD. 1302 14. Removed mention of "DNAME" from the discussion about [RFC3363]. 1304 15. Numerous updates to reflect newer versions of IPv6 documents, 1305 including [RFC4443], [RFC4291], [RFC3596], and [RFC4213]. 1307 16. Removed discussion of "Managed" and "Other" flags in RAs. There 1308 is no consensus at present on how to process these flags, and 1309 discussion of their semantics was removed in the most recent 1310 update of Stateless Address Autoconfiguration [RFC4862]. 1312 17. Added many more references to optional IPv6 documents. 1314 18. Made "A Recommendation for IPv6 Address Text Representation" 1315 [RFC5952] a SHOULD. 1317 19. Added reference to [RFC5722] (Overlapping Fragments), and made 1318 it a MUST to implement. 1320 20. Updated MLD section to include reference to Lightweight MLD 1321 [RFC5790]. 1323 21. Added SHOULD recommendation for "Default Router Preferences and 1324 More-Specific Routes" [RFC4191]. 1326 22. Made "IPv6 Flow Label Specification" [RFC6437] a SHOULD. 1328 22. References 1330 22.1. Normative References 1332 [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", 1333 STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, 1334 . 1336 [RFC1035] Mockapetris, P., "Domain names - implementation and 1337 specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, 1338 November 1987, . 1340 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1341 Requirement Levels", BCP 14, RFC 2119, 1342 DOI 10.17487/RFC2119, March 1997, 1343 . 1345 [RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast 1346 Listener Discovery (MLD) for IPv6", RFC 2710, 1347 DOI 10.17487/RFC2710, October 1999, 1348 . 1350 [RFC2711] Partridge, C. and A. Jackson, "IPv6 Router Alert Option", 1351 RFC 2711, DOI 10.17487/RFC2711, October 1999, 1352 . 1354 [RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group 1355 MIB", RFC 2863, DOI 10.17487/RFC2863, June 2000, 1356 . 1358 [RFC3168] Ramakrishnan, K., Floyd, S., and D. Black, "The Addition 1359 of Explicit Congestion Notification (ECN) to IP", 1360 RFC 3168, DOI 10.17487/RFC3168, September 2001, 1361 . 1363 [RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins, 1364 C., and M. Carney, "Dynamic Host Configuration Protocol 1365 for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July 1366 2003, . 1368 [RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An 1369 Architecture for Describing Simple Network Management 1370 Protocol (SNMP) Management Frameworks", STD 62, RFC 3411, 1371 DOI 10.17487/RFC3411, December 2002, 1372 . 1374 [RFC3596] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi, 1375 "DNS Extensions to Support IP Version 6", STD 88, 1376 RFC 3596, DOI 10.17487/RFC3596, October 2003, 1377 . 1379 [RFC3736] Droms, R., "Stateless Dynamic Host Configuration Protocol 1380 (DHCP) Service for IPv6", RFC 3736, DOI 10.17487/RFC3736, 1381 April 2004, . 1383 [RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener 1384 Discovery Version 2 (MLDv2) for IPv6", RFC 3810, 1385 DOI 10.17487/RFC3810, June 2004, 1386 . 1388 [RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S. 1389 Rose, "DNS Security Introduction and Requirements", 1390 RFC 4033, DOI 10.17487/RFC4033, March 2005, 1391 . 1393 [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. 1394 Rose, "Resource Records for the DNS Security Extensions", 1395 RFC 4034, DOI 10.17487/RFC4034, March 2005, 1396 . 1398 [RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S. 1399 Rose, "Protocol Modifications for the DNS Security 1400 Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005, 1401 . 1403 [RFC4213] Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms 1404 for IPv6 Hosts and Routers", RFC 4213, 1405 DOI 10.17487/RFC4213, October 2005, 1406 . 1408 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 1409 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 1410 2006, . 1412 [RFC4292] Haberman, B., "IP Forwarding Table MIB", RFC 4292, 1413 DOI 10.17487/RFC4292, April 2006, 1414 . 1416 [RFC4293] Routhier, S., Ed., "Management Information Base for the 1417 Internet Protocol (IP)", RFC 4293, DOI 10.17487/RFC4293, 1418 April 2006, . 1420 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 1421 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 1422 December 2005, . 1424 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 1425 RFC 4303, DOI 10.17487/RFC4303, December 2005, 1426 . 1428 [RFC4311] Hinden, R. and D. Thaler, "IPv6 Host-to-Router Load 1429 Sharing", RFC 4311, DOI 10.17487/RFC4311, November 2005, 1430 . 1432 [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet 1433 Control Message Protocol (ICMPv6) for the Internet 1434 Protocol Version 6 (IPv6) Specification", STD 89, 1435 RFC 4443, DOI 10.17487/RFC4443, March 2006, 1436 . 1438 [RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for 1439 IP", RFC 4607, DOI 10.17487/RFC4607, August 2006, 1440 . 1442 [RFC4632] Fuller, V. and T. Li, "Classless Inter-domain Routing 1443 (CIDR): The Internet Address Assignment and Aggregation 1444 Plan", BCP 122, RFC 4632, DOI 10.17487/RFC4632, August 1445 2006, . 1447 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 1448 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 1449 DOI 10.17487/RFC4861, September 2007, 1450 . 1452 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 1453 Address Autoconfiguration", RFC 4862, 1454 DOI 10.17487/RFC4862, September 2007, 1455 . 1457 [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy 1458 Extensions for Stateless Address Autoconfiguration in 1459 IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007, 1460 . 1462 [RFC5095] Abley, J., Savola, P., and G. Neville-Neil, "Deprecation 1463 of Type 0 Routing Headers in IPv6", RFC 5095, 1464 DOI 10.17487/RFC5095, December 2007, 1465 . 1467 [RFC5453] Krishnan, S., "Reserved IPv6 Interface Identifiers", 1468 RFC 5453, DOI 10.17487/RFC5453, February 2009, 1469 . 1471 [RFC5722] Krishnan, S., "Handling of Overlapping IPv6 Fragments", 1472 RFC 5722, DOI 10.17487/RFC5722, December 2009, 1473 . 1475 [RFC5790] Liu, H., Cao, W., and H. Asaeda, "Lightweight Internet 1476 Group Management Protocol Version 3 (IGMPv3) and Multicast 1477 Listener Discovery Version 2 (MLDv2) Protocols", RFC 5790, 1478 DOI 10.17487/RFC5790, February 2010, 1479 . 1481 [RFC5942] Singh, H., Beebee, W., and E. Nordmark, "IPv6 Subnet 1482 Model: The Relationship between Links and Subnet 1483 Prefixes", RFC 5942, DOI 10.17487/RFC5942, July 2010, 1484 . 1486 [RFC5952] Kawamura, S. and M. Kawashima, "A Recommendation for IPv6 1487 Address Text Representation", RFC 5952, 1488 DOI 10.17487/RFC5952, August 2010, 1489 . 1491 [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., 1492 and A. Bierman, Ed., "Network Configuration Protocol 1493 (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, 1494 . 1496 [RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme, 1497 "IPv6 Flow Label Specification", RFC 6437, 1498 DOI 10.17487/RFC6437, November 2011, 1499 . 1501 [RFC6564] Krishnan, S., Woodyatt, J., Kline, E., Hoagland, J., and 1502 M. Bhatia, "A Uniform Format for IPv6 Extension Headers", 1503 RFC 6564, DOI 10.17487/RFC6564, April 2012, 1504 . 1506 [RFC6724] Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown, 1507 "Default Address Selection for Internet Protocol Version 6 1508 (IPv6)", RFC 6724, DOI 10.17487/RFC6724, September 2012, 1509 . 1511 [RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762, 1512 DOI 10.17487/RFC6762, February 2013, 1513 . 1515 [RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service 1516 Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013, 1517 . 1519 [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. 1520 Bormann, "Neighbor Discovery Optimization for IPv6 over 1521 Low-Power Wireless Personal Area Networks (6LoWPANs)", 1522 RFC 6775, DOI 10.17487/RFC6775, November 2012, 1523 . 1525 [RFC6891] Damas, J., Graff, M., and P. Vixie, "Extension Mechanisms 1526 for DNS (EDNS(0))", STD 75, RFC 6891, 1527 DOI 10.17487/RFC6891, April 2013, 1528 . 1530 [RFC6946] Gont, F., "Processing of IPv6 "Atomic" Fragments", 1531 RFC 6946, DOI 10.17487/RFC6946, May 2013, 1532 . 1534 [RFC7045] Carpenter, B. and S. Jiang, "Transmission and Processing 1535 of IPv6 Extension Headers", RFC 7045, 1536 DOI 10.17487/RFC7045, December 2013, 1537 . 1539 [RFC7048] Nordmark, E. and I. Gashinsky, "Neighbor Unreachability 1540 Detection Is Too Impatient", RFC 7048, 1541 DOI 10.17487/RFC7048, January 2014, 1542 . 1544 [RFC7112] Gont, F., Manral, V., and R. Bonica, "Implications of 1545 Oversized IPv6 Header Chains", RFC 7112, 1546 DOI 10.17487/RFC7112, January 2014, 1547 . 1549 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 1550 Interface Identifiers with IPv6 Stateless Address 1551 Autoconfiguration (SLAAC)", RFC 7217, 1552 DOI 10.17487/RFC7217, April 2014, 1553 . 1555 [RFC7223] Bjorklund, M., "A YANG Data Model for Interface 1556 Management", RFC 7223, DOI 10.17487/RFC7223, May 2014, 1557 . 1559 [RFC7277] Bjorklund, M., "A YANG Data Model for IP Management", 1560 RFC 7277, DOI 10.17487/RFC7277, June 2014, 1561 . 1563 [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. 1564 Kivinen, "Internet Key Exchange Protocol Version 2 1565 (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October 1566 2014, . 1568 [RFC7527] Asati, R., Singh, H., Beebee, W., Pignataro, C., Dart, E., 1569 and W. George, "Enhanced Duplicate Address Detection", 1570 RFC 7527, DOI 10.17487/RFC7527, April 2015, 1571 . 1573 [RFC7559] Krishnan, S., Anipko, D., and D. Thaler, "Packet-Loss 1574 Resiliency for Router Solicitations", RFC 7559, 1575 DOI 10.17487/RFC7559, May 2015, 1576 . 1578 [RFC7608] Boucadair, M., Petrescu, A., and F. Baker, "IPv6 Prefix 1579 Length Recommendation for Forwarding", BCP 198, RFC 7608, 1580 DOI 10.17487/RFC7608, July 2015, 1581 . 1583 [RFC7739] Gont, F., "Security Implications of Predictable Fragment 1584 Identification Values", RFC 7739, DOI 10.17487/RFC7739, 1585 February 2016, . 1587 [RFC8021] Gont, F., Liu, W., and T. Anderson, "Generation of IPv6 1588 Atomic Fragments Considered Harmful", RFC 8021, 1589 DOI 10.17487/RFC8021, January 2017, 1590 . 1592 [RFC8028] Baker, F. and B. Carpenter, "First-Hop Router Selection by 1593 Hosts in a Multi-Prefix Network", RFC 8028, 1594 DOI 10.17487/RFC8028, November 2016, 1595 . 1597 [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF 1598 Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, 1599 . 1601 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 1602 "Recommendation on Stable IPv6 Interface Identifiers", 1603 RFC 8064, DOI 10.17487/RFC8064, February 2017, 1604 . 1606 [RFC8106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli, 1607 "IPv6 Router Advertisement Options for DNS Configuration", 1608 RFC 8106, DOI 10.17487/RFC8106, March 2017, 1609 . 1611 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1612 (IPv6) Specification", STD 86, RFC 8200, 1613 DOI 10.17487/RFC8200, July 2017, 1614 . 1616 [RFC8201] McCann, J., Deering, S., Mogul, J., and R. Hinden, Ed., 1617 "Path MTU Discovery for IP version 6", STD 87, RFC 8201, 1618 DOI 10.17487/RFC8201, July 2017, 1619 . 1621 [RFC8221] Wouters, P., Migault, D., Mattsson, J., Nir, Y., and T. 1622 Kivinen, "Cryptographic Algorithm Implementation 1623 Requirements and Usage Guidance for Encapsulating Security 1624 Payload (ESP) and Authentication Header (AH)", RFC 8221, 1625 DOI 10.17487/RFC8221, October 2017, 1626 . 1628 [RFC8247] Nir, Y., Kivinen, T., Wouters, P., and D. Migault, 1629 "Algorithm Implementation Requirements and Usage Guidance 1630 for the Internet Key Exchange Protocol Version 2 (IKEv2)", 1631 RFC 8247, DOI 10.17487/RFC8247, September 2017, 1632 . 1634 [RFC8311] Black, D., "Relaxing Restrictions on Explicit Congestion 1635 Notification (ECN) Experimentation", RFC 8311, 1636 DOI 10.17487/RFC8311, January 2018, 1637 . 1639 22.2. Informative References 1641 [I-D.ietf-v6ops-ipv6rtr-reqs] 1642 Kahn, Z., Brzozowski, J., and R. White, "Requirements for 1643 IPv6 Routers", draft-ietf-v6ops-ipv6rtr-reqs-01 (work in 1644 progress), January 2018. 1646 [RFC0793] Postel, J., "Transmission Control Protocol", STD 7, 1647 RFC 793, DOI 10.17487/RFC0793, September 1981, 1648 . 1650 [RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S. 1651 Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 1652 Functional Specification", RFC 2205, DOI 10.17487/RFC2205, 1653 September 1997, . 1655 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 1656 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 1657 . 1659 [RFC2491] Armitage, G., Schulter, P., Jork, M., and G. Harter, "IPv6 1660 over Non-Broadcast Multiple Access (NBMA) networks", 1661 RFC 2491, DOI 10.17487/RFC2491, January 1999, 1662 . 1664 [RFC2590] Conta, A., Malis, A., and M. Mueller, "Transmission of 1665 IPv6 Packets over Frame Relay Networks Specification", 1666 RFC 2590, DOI 10.17487/RFC2590, May 1999, 1667 . 1669 [RFC3146] Fujisawa, K. and A. Onoe, "Transmission of IPv6 Packets 1670 over IEEE 1394 Networks", RFC 3146, DOI 10.17487/RFC3146, 1671 October 2001, . 1673 [RFC3363] Bush, R., Durand, A., Fink, B., Gudmundsson, O., and T. 1674 Hain, "Representing Internet Protocol version 6 (IPv6) 1675 Addresses in the Domain Name System (DNS)", RFC 3363, 1676 DOI 10.17487/RFC3363, August 2002, 1677 . 1679 [RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J., and W. 1680 Stevens, "Basic Socket Interface Extensions for IPv6", 1681 RFC 3493, DOI 10.17487/RFC3493, February 2003, 1682 . 1684 [RFC3542] Stevens, W., Thomas, M., Nordmark, E., and T. Jinmei, 1685 "Advanced Sockets Application Program Interface (API) for 1686 IPv6", RFC 3542, DOI 10.17487/RFC3542, May 2003, 1687 . 1689 [RFC3646] Droms, R., Ed., "DNS Configuration options for Dynamic 1690 Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3646, 1691 DOI 10.17487/RFC3646, December 2003, 1692 . 1694 [RFC3678] Thaler, D., Fenner, B., and B. Quinn, "Socket Interface 1695 Extensions for Multicast Source Filters", RFC 3678, 1696 DOI 10.17487/RFC3678, January 2004, 1697 . 1699 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 1700 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 1701 2011, . 1703 [RFC3776] Arkko, J., Devarapalli, V., and F. Dupont, "Using IPsec to 1704 Protect Mobile IPv6 Signaling Between Mobile Nodes and 1705 Home Agents", RFC 3776, DOI 10.17487/RFC3776, June 2004, 1706 . 1708 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 1709 "SEcure Neighbor Discovery (SEND)", RFC 3971, 1710 DOI 10.17487/RFC3971, March 2005, 1711 . 1713 [RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)", 1714 RFC 3972, DOI 10.17487/RFC3972, March 2005, 1715 . 1717 [RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and 1718 More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191, 1719 November 2005, . 1721 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 1722 DOI 10.17487/RFC4302, December 2005, 1723 . 1725 [RFC4338] DeSanti, C., Carlson, C., and R. Nixon, "Transmission of 1726 IPv6, IPv4, and Address Resolution Protocol (ARP) Packets 1727 over Fibre Channel", RFC 4338, DOI 10.17487/RFC4338, 1728 January 2006, . 1730 [RFC4380] Huitema, C., "Teredo: Tunneling IPv6 over UDP through 1731 Network Address Translations (NATs)", RFC 4380, 1732 DOI 10.17487/RFC4380, February 2006, 1733 . 1735 [RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD) 1736 for IPv6", RFC 4429, DOI 10.17487/RFC4429, April 2006, 1737 . 1739 [RFC4584] Chakrabarti, S. and E. Nordmark, "Extension to Sockets API 1740 for Mobile IPv6", RFC 4584, DOI 10.17487/RFC4584, July 1741 2006, . 1743 [RFC4821] Mathis, M. and J. Heffner, "Packetization Layer Path MTU 1744 Discovery", RFC 4821, DOI 10.17487/RFC4821, March 2007, 1745 . 1747 [RFC4877] Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with 1748 IKEv2 and the Revised IPsec Architecture", RFC 4877, 1749 DOI 10.17487/RFC4877, April 2007, 1750 . 1752 [RFC4884] Bonica, R., Gan, D., Tappan, D., and C. Pignataro, 1753 "Extended ICMP to Support Multi-Part Messages", RFC 4884, 1754 DOI 10.17487/RFC4884, April 2007, 1755 . 1757 [RFC4890] Davies, E. and J. Mohacsi, "Recommendations for Filtering 1758 ICMPv6 Messages in Firewalls", RFC 4890, 1759 DOI 10.17487/RFC4890, May 2007, 1760 . 1762 [RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6 1763 over Low-Power Wireless Personal Area Networks (6LoWPANs): 1764 Overview, Assumptions, Problem Statement, and Goals", 1765 RFC 4919, DOI 10.17487/RFC4919, August 2007, 1766 . 1768 [RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, 1769 "Transmission of IPv6 Packets over IEEE 802.15.4 1770 Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007, 1771 . 1773 [RFC5014] Nordmark, E., Chakrabarti, S., and J. Laganier, "IPv6 1774 Socket API for Source Address Selection", RFC 5014, 1775 DOI 10.17487/RFC5014, September 2007, 1776 . 1778 [RFC5072] Varada, S., Ed., Haskins, D., and E. Allen, "IP Version 6 1779 over PPP", RFC 5072, DOI 10.17487/RFC5072, September 2007, 1780 . 1782 [RFC5121] Patil, B., Xia, F., Sarikaya, B., Choi, JH., and S. 1783 Madanapalli, "Transmission of IPv6 via the IPv6 1784 Convergence Sublayer over IEEE 802.16 Networks", RFC 5121, 1785 DOI 10.17487/RFC5121, February 2008, 1786 . 1788 [RFC5555] Soliman, H., Ed., "Mobile IPv6 Support for Dual Stack 1789 Hosts and Routers", RFC 5555, DOI 10.17487/RFC5555, June 1790 2009, . 1792 [RFC6563] Jiang, S., Conrad, D., and B. Carpenter, "Moving A6 to 1793 Historic Status", RFC 6563, DOI 10.17487/RFC6563, March 1794 2012, . 1796 [RFC7066] Korhonen, J., Ed., Arkko, J., Ed., Savolainen, T., and S. 1797 Krishnan, "IPv6 for Third Generation Partnership Project 1798 (3GPP) Cellular Hosts", RFC 7066, DOI 10.17487/RFC7066, 1799 November 2013, . 1801 [RFC7084] Singh, H., Beebee, W., Donley, C., and B. Stark, "Basic 1802 Requirements for IPv6 Customer Edge Routers", RFC 7084, 1803 DOI 10.17487/RFC7084, November 2013, 1804 . 1806 [RFC7123] Gont, F. and W. Liu, "Security Implications of IPv6 on 1807 IPv4 Networks", RFC 7123, DOI 10.17487/RFC7123, February 1808 2014, . 1810 [RFC7278] Byrne, C., Drown, D., and A. Vizdal, "Extending an IPv6 1811 /64 Prefix from a Third Generation Partnership Project 1812 (3GPP) Mobile Interface to a LAN Link", RFC 7278, 1813 DOI 10.17487/RFC7278, June 2014, 1814 . 1816 [RFC7371] Boucadair, M. and S. Venaas, "Updates to the IPv6 1817 Multicast Addressing Architecture", RFC 7371, 1818 DOI 10.17487/RFC7371, September 2014, 1819 . 1821 [RFC7421] Carpenter, B., Ed., Chown, T., Gont, F., Jiang, S., 1822 Petrescu, A., and A. Yourtchenko, "Analysis of the 64-bit 1823 Boundary in IPv6 Addressing", RFC 7421, 1824 DOI 10.17487/RFC7421, January 2015, 1825 . 1827 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 1828 Considerations for IPv6 Address Generation Mechanisms", 1829 RFC 7721, DOI 10.17487/RFC7721, March 2016, 1830 . 1832 [RFC7772] Yourtchenko, A. and L. Colitti, "Reducing Energy 1833 Consumption of Router Advertisements", BCP 202, RFC 7772, 1834 DOI 10.17487/RFC7772, February 2016, 1835 . 1837 [RFC7844] Huitema, C., Mrugalski, T., and S. Krishnan, "Anonymity 1838 Profiles for DHCP Clients", RFC 7844, 1839 DOI 10.17487/RFC7844, May 2016, 1840 . 1842 [RFC7934] Colitti, L., Cerf, V., Cheshire, S., and D. Schinazi, 1843 "Host Address Availability Recommendations", BCP 204, 1844 RFC 7934, DOI 10.17487/RFC7934, July 2016, 1845 . 1847 [RFC8096] Fenner, B., "The IPv6-Specific MIB Modules Are Obsolete", 1848 RFC 8096, DOI 10.17487/RFC8096, April 2017, 1849 . 1851 [RFC8273] Brzozowski, J. and G. Van de Velde, "Unique IPv6 Prefix 1852 per Host", RFC 8273, DOI 10.17487/RFC8273, December 2017, 1853 . 1855 [POSIX] IEEE, "IEEE Std. 1003.1-2008 Standard for Information 1856 Technology -- Portable Operating System Interface (POSIX), 1857 ISO/IEC 9945:2009", . 1859 [USGv6] National Institute of Standards and Technology, "A Profile 1860 for IPv6 in the U.S. Government - Version 1.0", July 2008, 1861 . 1863 Authors' Addresses 1865 Tim Chown 1866 Jisc 1867 Lumen House, Library Avenue 1868 Harwell Oxford, Didcot OX11 0SG 1869 United Kingdom 1871 Email: tim.chown@jisc.ac.uk 1873 John Loughney 1874 Intel 1875 Santa Clara, CA 1876 USA 1878 Email: john.loughney@gmail.com 1880 Timothy Winters 1881 University of New Hampshire, Interoperability Lab (UNH-IOL) 1882 Durham, NH 1883 United States 1885 Email: twinters@iol.unh.edu