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Checking references for intended status: Informational ---------------------------------------------------------------------------- ** Obsolete normative reference: RFC 3315 (Obsoleted by RFC 8415) ** Obsolete normative reference: RFC 3736 (Obsoleted by RFC 8415) ** Obsolete normative reference: RFC 4941 (Obsoleted by RFC 8981) ** Obsolete normative reference: RFC 7223 (Obsoleted by RFC 8343) ** Obsolete normative reference: RFC 7277 (Obsoleted by RFC 8344) == Outdated reference: A later version (-04) exists of draft-ietf-v6ops-ipv6rtr-reqs-00 -- Obsolete informational reference (is this intentional?): RFC 793 (Obsoleted by RFC 9293) Summary: 5 errors (**), 0 flaws (~~), 2 warnings (==), 2 comments (--). 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: Informational Intel 6 Expires: May 2, 2018 T. Winters 7 University of New Hampshire 8 October 29, 2017 10 IPv6 Node Requirements 11 draft-ietf-6man-rfc6434-bis-02 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 May 2, 2018. 40 Copyright Notice 42 Copyright (c) 2017 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 . . . . . . . . . . . . . . . . . 17 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 . . . . . . . . . . . . . . . . . . . . . . 20 107 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 . . . . . . . . . 21 111 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 16.2. YANG Data Models . . . . . . . . . . . . . . . . . . . . 23 121 16.2.1. IP Management YANG Model . . . . . . . . . . . . . . 23 122 16.2.2. System Management YANG Model . . . . . . . . . . . . 24 123 16.2.3. System 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 . . . . . . . 24 130 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 . . . . . . . . . . . . . . . . . . . . . . . 39 137 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 ATM Asynchronous Transfer Mode 209 AH Authentication Header 210 DAD Duplicate Address Detection 211 ESP Encapsulating Security Payload 212 ICMP Internet Control Message Protocol 213 IKE Internet Key Exchange 214 MIB Management Information Base 215 MLD Multicast Listener Discovery 216 MTU Maximum Transmission Unit 217 NA Neighbor Advertisement 218 NBMA Non-Broadcast Multiple Access 219 ND Neighbor Discovery 220 NS Neighbor Solicitation 221 NUD Neighbor Unreachability Detection 222 PPP Point-to-Point Protocol 224 4. Sub-IP Layer 226 An IPv6 node must include support for one or more IPv6 link-layer 227 specifications. Which link-layer specifications an implementation 228 should include will depend upon what link-layers are supported by the 229 hardware available on the system. It is possible for a conformant 230 IPv6 node to support IPv6 on some of its interfaces and not on 231 others. 233 As IPv6 is run over new layer 2 technologies, it is expected that new 234 specifications will be issued. In the following, we list some of the 235 layer 2 technologies for which an IPv6 specification has been 236 developed. It is provided for informational purposes only and may 237 not be complete. 239 - Transmission of IPv6 Packets over Ethernet Networks [RFC2464] 241 - Transmission of IPv6 Packets over Frame Relay Networks 242 Specification [RFC2590] 244 - Transmission of IPv6 Packets over IEEE 1394 Networks [RFC3146] 246 - Transmission of IPv6, IPv4, and Address Resolution Protocol (ARP) 247 Packets over Fibre Channel [RFC4338] 249 - Transmission of IPv6 Packets over IEEE 802.15.4 Networks [RFC4944] 251 - Transmission of IPv6 via the IPv6 Convergence Sublayer over IEEE 252 802.16 Networks [RFC5121] 254 - IP version 6 over PPP [RFC5072] 256 In addition to traditional physical link-layers, it is also possible 257 to tunnel IPv6 over other protocols. Examples include: 259 - Teredo: Tunneling IPv6 over UDP through Network Address 260 Translations (NATs) [RFC4380] 262 - Section 3 of "Basic Transition Mechanisms for IPv6 Hosts and 263 Routers" [RFC4213] 265 5. IP Layer 267 5.1. Internet Protocol Version 6 - RFC 8200 269 The Internet Protocol Version 6 is specified in [RFC8200]. This 270 specification MUST be supported. 272 Any unrecognized extension headers or options MUST be processed as 273 described in RFC 8200. 275 The node MUST follow the packet transmission rules in RFC 8200. 277 Nodes MUST always be able to send, receive, and process fragment 278 headers. All conformant IPv6 implementations MUST be capable of 279 sending and receiving IPv6 packets; the forwarding functionality MAY 280 be supported. Overlapping fragments MUST be handled as described in 281 [RFC5722]. 283 [RFC6946] discusses IPv6 atomic fragments, and recommends that IPv6 284 atomic fragments are processed independently of any other fragments, 285 to protect against fragmentation-based attacks. [RFC8021] goes 286 further and recommends the deprecation of atomic fragments. Nodes 287 thus MUST NOT generate atomic fragments. 289 To mitigate a variety of potential attacks, nodes SHOULD avoid using 290 predictable fragment Identification values in Fragment Headers, as 291 discussed in [RFC7739]. 293 All nodes SHOULD support the setting and use of the IPv6 Flow Label 294 field as defined in the IPv6 Flow Label specification [RFC6437]. 295 Forwarding nodes such as routers and load distributors MUST NOT 296 depend only on Flow Label values being uniformly distributed. It is 297 RECOMMENDED that source hosts support the flow label by setting the 298 Flow Label field for all packets of a given flow to the same value 299 chosen from an approximation to a discrete uniform distribution. 301 5.2. Support for IPv6 Extension Headers 303 RFC 8200 specifies extension headers and the processing for these 304 headers. 306 An IPv6 node MUST be able to process these headers. An exception is 307 Routing Header type 0 (RH0), which was deprecated by [RFC5095] due to 308 security concerns and which MUST be treated as an unrecognized 309 routing type. 311 Further, [RFC7045] adds specific requirements for processing of 312 Extension Headers, in particular that any forwarding node along an 313 IPv6 packet's path, which forwards the packet for any reason, SHOULD 314 do so regardless of any extension headers that are present. 316 [RFC7112] discusses issues with oversized IPv6 Extension Header 317 chains, and states that when a node fragments an IPv6 datagram, it 318 MUST include the entire IPv6 Header Chain in the First Fragment. 320 As stated in RFC8200, extension headers (except for the Hop-by-Hop 321 Options header) are not processed, inserted, or deleted by any node 322 along a packet's delivery path, until the packet reaches the node (or 323 each of the set of nodes, in the case of multicast) identified in the 324 Destination Address field of the IPv6 header. 326 Should a new type of Extension Header need to be defined, its format 327 MUST follow the consistent format described in Section 4 of 328 [RFC6564]. 330 5.3. Protecting a node from excessive EH options 332 Per RFC 8200, end hosts are expected to process all extension 333 headers, destination options, and hop-by-hop options in a packet. 334 Given that the only limit on the number and size of extension headers 335 is the MTU, the processing of received packets could be considerable. 336 It is also conceivable that a long chain of extension headers might 337 be used as a form of denial-of-service attack. Accordingly, a host 338 may place limits on the number and sizes of extension headers and 339 options it is willing to process. 341 A host MAY limit the number of consecutive PAD1 options in 342 destination options or hop-by-hop options to seven. In this case, if 343 the more than seven consecutive PAD1 options are present the the 344 packet should be silently discarded. The rationale is that if 345 padding of eight or more bytes is required than the PADN option 346 should be used. 348 A host MAY limit number of bytes in a PADN option to be less than 349 eight. In such a case, if a PADN option is present that has a length 350 greater than seven then the packet should be silently discarded. The 351 rationale for this guideline is that the purpose of padding is for 352 alignment and eight bytes is the maximum alignment used in IPv6. 354 A host MAY disallow unknown options in destination options or hob-by- 355 hop options. This should be configurable where the default is to 356 accept unknown options and process them per RFC2460. If a packet 357 with unknown options is received and the host is configured to 358 disallow them, then the packet should be silently discarded. 360 A host MAY impose a limit on the maximum number of non-padding 361 options allowed in a destination options and hop-by-hop extension 362 headers. If this feature is supported the maximum number should be 363 configurable and the default value SHOULD be set to eight. The 364 limits for destination options and hop-by-hop options may be 365 separately configurable. If a packet is received and the number of 366 destination or hop-by-hop optines exceeds the limit, then the packet 367 should be silently discarded. 369 A host MAY impose a limit on the maximum length of destination 370 options or hop-by-hop options extension header. This value should be 371 configurable and the default is to accept options of any length. If 372 a packet is received and the length of destination or hop-by-hop 373 options extension header exceeds the length limit, then the packet 374 should be silently discarded. 376 5.4. Neighbor Discovery for IPv6 - RFC 4861 378 Neighbor Discovery is defined in [RFC4861]; the definition was 379 updated by [RFC5942]. Neighbor Discovery SHOULD be supported. RFC 380 4861 states: 382 Unless specified otherwise (in a document that covers operating IP 383 over a particular link type) this document applies to all link 384 types. However, because ND uses link-layer multicast for some of 385 its services, it is possible that on some link types (e.g., Non- 386 Broadcast Multi-Access (NBMA) links), alternative protocols or 387 mechanisms to implement those services will be specified (in the 388 appropriate document covering the operation of IP over a 389 particular link type). The services described in this document 390 that are not directly dependent on multicast, such as Redirects, 391 next-hop determination, Neighbor Unreachability Detection, etc., 392 are expected to be provided as specified in this document. The 393 details of how one uses ND on NBMA links are addressed in 394 [RFC2491]. 396 Some detailed analysis of Neighbor Discovery follows: 398 Router Discovery is how hosts locate routers that reside on an 399 attached link. Hosts MUST support Router Discovery functionality. 401 Prefix Discovery is how hosts discover the set of address prefixes 402 that define which destinations are on-link for an attached link. 403 Hosts MUST support Prefix Discovery. 405 Hosts MUST also implement Neighbor Unreachability Detection (NUD) for 406 all paths between hosts and neighboring nodes. NUD is not required 407 for paths between routers. However, all nodes MUST respond to 408 unicast Neighbor Solicitation (NS) messages. 410 [RFC7048] discusses NUD, in particular cases where it behaves too 411 impatiently. It states that if a node transmits more than a certain 412 number of packets, then it SHOULD use the exponential backoff of the 413 retransmit timer, up to a certain threshold point. 415 Hosts MUST support the sending of Router Solicitations and the 416 receiving of Router Advertisements. The ability to understand 417 individual Router Advertisement options is dependent on supporting 418 the functionality making use of the particular option. 420 [RFC7559] discusses packet loss resliency for Router Solicitations, 421 and requires that nodes MUST use a specific exponential backoff 422 algorithm for RS retransmissions. 424 All nodes MUST support the sending and receiving of Neighbor 425 Solicitation (NS) and Neighbor Advertisement (NA) messages. NS and 426 NA messages are required for Duplicate Address Detection (DAD). 428 Hosts SHOULD support the processing of Redirect functionality. 429 Routers MUST support the sending of Redirects, though not necessarily 430 for every individual packet (e.g., due to rate limiting). Redirects 431 are only useful on networks supporting hosts. In core networks 432 dominated by routers, Redirects are typically disabled. The sending 433 of Redirects SHOULD be disabled by default on backbone routers. They 434 MAY be enabled by default on routers intended to support hosts on 435 edge networks. 437 "IPv6 Host-to-Router Load Sharing" [RFC4311] includes additional 438 recommendations on how to select from a set of available routers. 439 [RFC4311] SHOULD be supported. 441 5.5. SEcure Neighbor Discovery (SEND) - RFC 3971 443 SEND [RFC3971] and Cryptographically Generated Addresses (CGAs) 444 [RFC3972] provide a way to secure the message exchanges of Neighbor 445 Discovery. SEND has the potential to address certain classes of 446 spoofing attacks, but it does not provide specific protection for 447 threats from off-link attackers. It requires relatively heavyweight 448 provisioning, so is only likely to be used in scenarios where 449 security considerations are particularly important. 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, its deployment is only likely to be considered where 457 nodes are operating in a particularly strict security environment. 459 5.6. IPv6 Router Advertisement Flags Option - RFC 5175 461 Router Advertisements include an 8-bit field of single-bit Router 462 Advertisement flags. The Router Advertisement Flags Option extends 463 the number of available flag bits by 48 bits. At the time of this 464 writing, 6 of the original 8 single-bit flags have been assigned, 465 while 2 remain available for future assignment. No flags have been 466 defined that make use of the new option, and thus, strictly speaking, 467 there is no requirement to implement the option today. However, 468 implementations that are able to pass unrecognized options to a 469 higher-level entity that may be able to understand them (e.g., a 470 user-level process using a "raw socket" facility) MAY take steps to 471 handle the option in anticipation of a future usage. 473 5.7. Path MTU Discovery and Packet Size 475 5.7.1. Path MTU Discovery - RFC 8201 477 "Path MTU Discovery for IP version 6" [RFC8201] SHOULD be supported. 478 From [RFC8200]: 480 It is strongly recommended that IPv6 nodes implement Path MTU 481 Discovery [RFC8201], in order to discover and take advantage of 482 path MTUs greater than 1280 octets. However, a minimal IPv6 483 implementation (e.g., in a boot ROM) may simply restrict itself to 484 sending packets no larger than 1280 octets, and omit 485 implementation of Path MTU Discovery. 487 The rules in [RFC8200] and [RFC5722] MUST be followed for packet 488 fragmentation and reassembly. 490 One operational issue with Path MTU Discovery occurs when firewalls 491 block ICMP Packet Too Big messages. Path MTU Discovery relies on 492 such messages to determine what size messages can be successfully 493 sent. "Packetization Layer Path MTU Discovery" [RFC4821] avoids 494 having a dependency on Packet Too Big messages. 496 5.7.2. Minimum MTU considerations 498 While an IPv6 link MTU can be set to 1280 bytes, for IPv6 UDP in 499 particular, which includes DNS operation, it is recommended that the 500 sender use a large MTU if they can, in order to avoid gratuitous 501 fragmentation-caused packet drops. 503 5.8. ICMP for the Internet Protocol Version 6 (IPv6) - RFC 4443 505 ICMPv6 [RFC4443] MUST be supported. "Extended ICMP to Support Multi- 506 Part Messages" [RFC4884] MAY be supported. 508 5.9. Default Router Preferences and More-Specific Routes - RFC 4191 510 "Default Router Preferences and More-Specific Routes" [RFC4191] 511 provides support for nodes attached to multiple (different) networks, 512 each providing routers that advertise themselves as default routers 513 via Router Advertisements. In some scenarios, one router may provide 514 connectivity to destinations the other router does not, and choosing 515 the "wrong" default router can result in reachability failures. In 516 order to resolve this scenario IPv6 Nodes MUST implement [RFC4191] 517 and SHOULD implement Type C host role. 519 5.10. First-Hop Router Selection - RFC 8028 521 In multihomed scenarios, where a host has more than one prefix, each 522 allocated by an upstream network that is assumed to implement BCP 38 523 ingress filtering, the host may have multiple routers to choose from. 525 Hosts that may be deployed in such multihomed environments SHOULD 526 follow the guidance given in [RFC8028]. 528 5.11. Multicast Listener Discovery (MLD) for IPv6 - RFC 3810 530 Nodes that need to join multicast groups MUST support MLDv2 531 [RFC3810]. MLD is needed by any node that is expected to receive and 532 process multicast traffic and in particular MLDv2 is required for 533 support for source-specific multicast (SSM) as per [RFC4607]. 535 Previous version of this document only required MLDv1 to be 536 implemented on all nodes. Since participation of any MLDv1-only 537 nodes on a link require that all other nodeas on the link then 538 operate in version 1 compatibility mode, the requirement to support 539 MLDv2 on all nodes was upgraded to a MUST. Further, SSM is now the 540 preferred multicast distribution method, rather than ASM. 542 Note that Neighbor Discovery (as used on most link types -- see 543 Section 5.4) depends on multicast and requires that nodes join 544 Solicited Node multicast addresses. 546 5.12. Explicit Congestion Notification (ECN) - RFC 3168 548 An ECN-aware router may set a mark in the IP header instead of 549 dropping a packet in order to signal impending congestion. The 550 receiver of the packet echoes the congestion indication to the 551 sender, which can then reduce its transmission rate as if it detected 552 a dropped packet. 554 Nodes that may be deployed in environments where they would benefit 555 from such early congestion notification SHOULD implement [RFC3168]. 557 ** BIS - but note draft-ietf-tsvwg-ecn-experimentation-03, e.g., 558 nonce comment 560 6. Addressing and Address Configuration 562 6.1. IP Version 6 Addressing Architecture - RFC 4291 564 The IPv6 Addressing Architecture [RFC4291] MUST be supported. 566 The current IPv6 Address Architecture is based on a 64-bit boundary 567 for subnet prefixes. The reasoning behind this decision is 568 documented in [RFC7421]. 570 6.2. Host Address Availability Recommendations 572 Hosts may be configured with addresses through a variety of methods, 573 including SLAAC, DHCPv6, or manual configuration. 575 [RFC7934] recommends that networks provide general-purpose end hosts 576 with multiple global IPv6 addresses when they attach, and it 577 describes the benefits of and the options for doing so. 579 Nodes SHOULD support the capability to be assigned a prefix per host 580 as documented in Unique IPv6 Prefix Per Host 581 [I-D.ietf-v6ops-unique-ipv6-prefix-per-host]. Such an approach can 582 offer improved host isolation and enhanced subscriber management on 583 shared network segments. 585 6.3. IPv6 Stateless Address Autoconfiguration - RFC 4862 587 Hosts MUST support IPv6 Stateless Address Autoconfiguration. It is 588 recommended, as described in [RFC8064], that unless there is a 589 specific requirement for MAC addresses to be embedded in an IID, 590 nodes follow the procedure in [RFC7217] to generate SLAAC-based 591 addresses, rather than using [RFC4862]. Addresses generated through 592 RFC7217 will be the same whenever a given device (re)appears on the 593 same subnet (with a specific IPv6 prefix), but the IID will vary on 594 each subnet visited. 596 Nodes that are routers MUST be able to generate link-local addresses 597 as described in [RFC4862]. 599 From RFC 4862: 601 The autoconfiguration process specified in this document applies 602 only to hosts and not routers. Since host autoconfiguration uses 603 information advertised by routers, routers will need to be 604 configured by some other means. However, it is expected that 605 routers will generate link-local addresses using the mechanism 606 described in this document. In addition, routers are expected to 607 successfully pass the Duplicate Address Detection procedure 608 described in this document on all addresses prior to assigning 609 them to an interface. 611 All nodes MUST implement Duplicate Address Detection. Quoting from 612 Section 5.4 of RFC 4862: 614 Duplicate Address Detection MUST be performed on all unicast 615 addresses prior to assigning them to an interface, regardless of 616 whether they are obtained through stateless autoconfiguration, 617 DHCPv6, or manual configuration, with the following [exceptions 618 noted therein]. 620 "Optimistic Duplicate Address Detection (DAD) for IPv6" [RFC4429] 621 specifies a mechanism to reduce delays associated with generating 622 addresses via Stateless Address Autoconfiguration [RFC4862]. RFC 623 4429 was developed in conjunction with Mobile IPv6 in order to reduce 624 the time needed to acquire and configure addresses as devices quickly 625 move from one network to another, and it is desirable to minimize 626 transition delays. For general purpose devices, RFC 4429 remains 627 optional at this time. 629 [RFC7527] discusses enhanced DAD, and describes an algorithm to 630 automate the detection of looped back IPv6 ND messages used by DAD. 631 Nodes SHOULD implement this behaviour where such detection is 632 beneficial. 634 6.4. Privacy Extensions for Address Configuration in IPv6 - RFC 4941 636 A node using Stateless Address Autoconfiguration [RFC4862] to form a 637 globally unique IPv6 address using its MAC address to generate the 638 IID will see that IID remain the same on any visited network, even 639 though the network prefix part changes. Thus it is possible for 3rd 640 party devices such nodes communicate with to track the activities of 641 the node as it moves around the network. Privacy Extensions for 642 Stateless Address Autoconfiguration [RFC4941] address this concern by 643 allowing nodes to configure an additional temporary address where the 644 IID is effectively randomly generated. Privacy addresses are then 645 used as source addresses for new communications initiated by the 646 node. 648 [RFC7721] discusses general privacy issues with IPv6 addressing. 650 RFC 4941 SHOULD be supported. In some scenarios, such as dedicated 651 servers in a data center, it provides limited or no benefit, or may 652 complicate network management. Thus devices implementing this 653 specification MUST provide a way for the end user to explicitly 654 enable or disable the use of such temporary addresses. 656 Note that RFC4941 can be used independently of traditional SLAAC, or 657 of RFC7217-based SLAAC. 659 Implementers of RFC 4941 should be aware that certain addresses are 660 reserved and should not be chosen for use as temporary addresses. 662 Consult "Reserved IPv6 Interface Identifiers" [RFC5453] for more 663 details. 665 6.5. Stateful Address Autoconfiguration (DHCPv6) - RFC 3315 667 DHCPv6 [RFC3315] can be used to obtain and configure addresses. In 668 general, a network may provide for the configuration of addresses 669 through Router Advertisements, DHCPv6, or both. There will be a wide 670 range of IPv6 deployment models and differences in address assignment 671 requirements, some of which may require DHCPv6 for stateful address 672 assignment. Consequently, all hosts SHOULD implement address 673 configuration via DHCPv6. 675 In the absence of a router, IPv6 nodes using DHCP for address 676 assignment MAY initiate DHCP to obtain IPv6 addresses and other 677 configuration information, as described in Section 5.5.2 of 678 [RFC4862]. 680 Where devices are likely to be carried by users and attached to 681 multiple visisted networks, DHCPv6 client anonymity profiles SHOULD 682 be supported as described in [RFC7844] to minimise the discolosure of 683 identifying information. Section 5 of RFC7844 describes operational 684 considerations on the use of such anonymity profiles. 686 6.6. Default Address Selection for IPv6 - RFC 6724 688 IPv6 nodes will invariably have multiple addresses configured 689 simultaneously, and thus will need to choose which addresses to use 690 for which communications. The rules specified in the Default Address 691 Selection for IPv6 [RFC6724] document MUST be implemented. Since 692 [RFC8028] updates rule 5.5 from [RFC6724] implementations SHOULD 693 implement this rule. 695 7. DNS 697 DNS is described in [RFC1034], [RFC1035], [RFC3363], and [RFC3596]. 698 Not all nodes will need to resolve names; those that will never need 699 to resolve DNS names do not need to implement resolver functionality. 700 However, the ability to resolve names is a basic infrastructure 701 capability on which applications rely, and most nodes will need to 702 provide support. All nodes SHOULD implement stub-resolver [RFC1034] 703 functionality, as in [RFC1034], Section 5.3.1, with support for: 705 - AAAA type Resource Records [RFC3596]; 707 - reverse addressing in ip6.arpa using PTR records [RFC3596]; 708 - Extension Mechanisms for DNS (EDNS0) [RFC6891] to allow for DNS 709 packet sizes larger than 512 octets. 711 Those nodes are RECOMMENDED to support DNS security extensions 712 [RFC4033] [RFC4034] [RFC4035]. 714 A6 Resource Records, which were only ever defined with Experimental 715 status in [RFC3363], are now classified as Historic, as per 716 [RFC6563]. 718 8. Configuring Non-Address Information 720 8.1. DHCP for Other Configuration Information 722 IPv6 nodes use DHCP [RFC3315] to obtain address configuration 723 information (see Section 6.5) and to obtain additional (non-address) 724 configuration. If a host implementation supports applications or 725 other protocols that require configuration that is only available via 726 DHCP, hosts SHOULD implement DHCP. For specialized devices on which 727 no such configuration need is present, DHCP may not be necessary. 729 An IPv6 node can use the subset of DHCP (described in [RFC3736]) to 730 obtain other configuration information. 732 8.2. Router Advertisements and Default Gateway 734 There is no defined DHCPv6 Gateway option. 736 Nodes using the Dynamic Host Configuration Protocol for IPv6 (DHCPv6) 737 are thus expected to determine their default router information and 738 on-link prefix information from received Router Advertisements. 740 8.3. IPv6 Router Advertisement Options for DNS Configuration - RFC 8106 742 Router Advertisements have historically limited options to those that 743 are critical to basic IPv6 functioning. Originally, DNS 744 configuration was not included as an RA option, and DHCP was the 745 recommended way to obtain DNS configuration information. Over time, 746 the thinking surrounding such an option has evolved. It is now 747 generally recognized that few nodes can function adequately without 748 having access to a working DNS resolver, and thus a Standards Track 749 document has been published to provide this capability [RFC8106]. 751 Implementations MUST include support for the DNS RA option [RFC8106]. 753 8.4. DHCP Options versus Router Advertisement Options for Host 754 Configuration 756 In IPv6, there are two main protocol mechanisms for propagating 757 configuration information to hosts: Router Advertisements (RAs) and 758 DHCP. RA options have been restricted to those deemed essential for 759 basic network functioning and for which all nodes are configured with 760 exactly the same information. Examples include the Prefix 761 Information Options, the MTU option, etc. On the other hand, DHCP 762 has generally been preferred for configuration of more general 763 parameters and for parameters that may be client-specific. Generally 764 speaking, however, there has been a desire to define only one 765 mechanism for configuring a given option, rather than defining 766 multiple (different) ways of configuring the same information. 768 One issue with having multiple ways of configuring the same 769 information is that interoperability suffers if a host chooses one 770 mechanism but the network operator chooses a different mechanism. 771 For "closed" environments, where the network operator has significant 772 influence over what devices connect to the network and thus what 773 configuration mechanisms they support, the operator may be able to 774 ensure that a particular mechanism is supported by all connected 775 hosts. In more open environments, however, where arbitrary devices 776 may connect (e.g., a WIFI hotspot), problems can arise. To maximize 777 interoperability in such environments, hosts would need to implement 778 multiple configuration mechanisms to ensure interoperability. 780 9. Service Discovery Protocols 782 [RFC6762] and [RFC6763] describe multicast DNS (mDNS) and DNS-Based 783 Service Discovery (DNS-SD) respectively. These protocols, 784 collectively commonly referred to as the 'Bonjour' protocols after 785 their naming by Apple, provide the means for devices to discover 786 services within a local link and, in the absence of a unicast DNS 787 service, to exchange naming information. 789 Where devices are to be deployed in networks where service dicovery 790 would be beneficial, e.g., for users seeking to discover printers or 791 display devices, mDNS and DNS-SD SHOULD be supported. 793 The IETF dnssd WG is defining solutions for DNS-based service 794 discovery in multi-link networks. 796 10. IPv4 Support and Transition 798 IPv6 nodes MAY support IPv4. 800 10.1. Transition Mechanisms 802 10.1.1. Basic Transition Mechanisms for IPv6 Hosts and Routers - RFC 803 4213 805 If an IPv6 node implements dual stack and tunneling, then [RFC4213] 806 MUST be supported. 808 11. Application Support 810 11.1. Textual Representation of IPv6 Addresses - RFC 5952 812 Software that allows users and operators to input IPv6 addresses in 813 text form SHOULD support "A Recommendation for IPv6 Address Text 814 Representation" [RFC5952]. 816 11.2. Application Programming Interfaces (APIs) 818 There are a number of IPv6-related APIs. This document does not 819 mandate the use of any, because the choice of API does not directly 820 relate to on-the-wire behavior of protocols. Implementers, however, 821 would be advised to consider providing a common API or reviewing 822 existing APIs for the type of functionality they provide to 823 applications. 825 "Basic Socket Interface Extensions for IPv6" [RFC3493] provides IPv6 826 functionality used by typical applications. Implementers should note 827 that RFC3493 has been picked up and further standardized by the 828 Portable Operating System Interface (POSIX) [POSIX]. 830 "Advanced Sockets Application Program Interface (API) for IPv6" 831 [RFC3542] provides access to advanced IPv6 features needed by 832 diagnostic and other more specialized applications. 834 "IPv6 Socket API for Source Address Selection" [RFC5014] provides 835 facilities that allow an application to override the default Source 836 Address Selection rules of [RFC6724]. 838 "Socket Interface Extensions for Multicast Source Filters" [RFC3678] 839 provides support for expressing source filters on multicast group 840 memberships. 842 "Extension to Sockets API for Mobile IPv6" [RFC4584] provides 843 application support for accessing and enabling Mobile IPv6 [RFC6275] 844 features. 846 12. Mobility 848 Mobile IPv6 [RFC6275] and associated specifications [RFC3776] 849 [RFC4877] allow a node to change its point of attachment within the 850 Internet, while maintaining (and using) a permanent address. All 851 communication using the permanent address continues to proceed as 852 expected even as the node moves around. The definition of Mobile IP 853 includes requirements for the following types of nodes: 855 - mobile nodes 857 - correspondent nodes with support for route optimization 859 - home agents 861 - all IPv6 routers 863 At the present time, Mobile IP has seen only limited implementation 864 and no significant deployment, partly because it originally assumed 865 an IPv6-only environment rather than a mixed IPv4/IPv6 Internet. 866 Recently, additional work has been done to support mobility in mixed- 867 mode IPv4 and IPv6 networks [RFC5555]. 869 More usage and deployment experience is needed with mobility before 870 any specific approach can be recommended for broad implementation in 871 all hosts and routers. Consequently, [RFC6275], [RFC5555], and 872 associated standards such as [RFC4877] are considered a MAY at this 873 time. 875 IPv6 for 3GPP [RFC7066] lists a snapshot of required IPv6 876 Functionalities at the time the document was published that would 877 need to be implemented, going above and beyond the recommendations in 878 this document. Additionally a 3GPP IPv6 Host MAY implement [RFC7278] 879 for delivering IPv6 prefixes on the LAN link. 881 13. Security 883 This section describes the specification for security for IPv6 nodes. 885 Achieving security in practice is a complex undertaking. Operational 886 procedures, protocols, key distribution mechanisms, certificate 887 management approaches, etc., are all components that impact the level 888 of security actually achieved in practice. More importantly, 889 deficiencies or a poor fit in any one individual component can 890 significantly reduce the overall effectiveness of a particular 891 security approach. 893 IPsec provides channel security at the Internet layer, making it 894 possible to provide secure communication for all (or a subset of) 895 communication flows at the IP layer between pairs of internet nodes. 896 IPsec provides sufficient flexibility and granularity that individual 897 TCP connections can (selectively) be protected, etc. 899 Although IPsec can be used with manual keying in some cases, such 900 usage has limited applicability and is not recommended. 902 A range of security technologies and approaches proliferate today 903 (e.g., IPsec, Transport Layer Security (TLS), Secure SHell (SSH), 904 etc.) No one approach has emerged as an ideal technology for all 905 needs and environments. Moreover, IPsec is not viewed as the ideal 906 security technology in all cases and is unlikely to displace the 907 others. 909 Previously, IPv6 mandated implementation of IPsec and recommended the 910 key management approach of IKE. This document updates that 911 recommendation by making support of the IPsec Architecture [RFC4301] 912 a SHOULD for all IPv6 nodes. Note that the IPsec Architecture 913 requires (e.g., Section 4.5 of RFC 4301) the implementation of both 914 manual and automatic key management. Currently, the default 915 automated key management protocol to implement is IKEv2 [RFC7296]. 917 This document recognizes that there exists a range of device types 918 and environments where approaches to security other than IPsec can be 919 justified. For example, special-purpose devices may support only a 920 very limited number or type of applications, and an application- 921 specific security approach may be sufficient for limited management 922 or configuration capabilities. Alternatively, some devices may run 923 on extremely constrained hardware (e.g., sensors) where the full 924 IPsec Architecture is not justified. 926 Because most common platforms now support IPv6 and have it enabled by 927 default, IPv6 security is an issue for networks that are ostensibly 928 IPv4-only; see [RFC7123] for guidance on this area. 930 13.1. Requirements 932 "Security Architecture for the Internet Protocol" [RFC4301] SHOULD be 933 supported by all IPv6 nodes. Note that the IPsec Architecture 934 requires (e.g., Section 4.5 of [RFC4301]) the implementation of both 935 manual and automatic key management. Currently, the default 936 automated key management protocol to implement is IKEv2. As required 937 in [RFC4301], IPv6 nodes implementing the IPsec Architecture MUST 938 implement ESP [RFC4303] and MAY implement AH [RFC4302]. 940 13.2. Transforms and Algorithms 942 The current set of mandatory-to-implement algorithms for the IPsec 943 Architecture are defined in "Cryptographic Algorithm Implementation 944 Requirements For ESP and AH" [RFC8221]. IPv6 nodes implementing the 945 IPsec Architecture MUST conform to the requirements in [RFC8221]. 946 Preferred cryptographic algorithms often change more frequently than 947 security protocols. Therefore, implementations MUST allow for 948 migration to new algorithms, as RFC 8221 is replaced or updated in 949 the future. 951 The current set of mandatory-to-implement algorithms for IKEv2 are 952 defined in "Cryptographic Algorithms for Use in the Internet Key 953 Exchange Version 2 (IKEv2)" [RFC8247]. IPv6 nodes implementing IKEv2 954 MUST conform to the requirements in [RFC8247] and/or any future 955 updates or replacements to [RFC8247]. 957 14. Router-Specific Functionality 959 This section defines general host considerations for IPv6 nodes that 960 act as routers. Currently, this section does not discuss detailed 961 routing-specific requirements; for the case of typical home routers, 962 [RFC7084] defines basic requirements for customer edge routers. 964 Further recommendations on router-specific functionality can be found 965 in [I-D.ietf-v6ops-ipv6rtr-reqs]. 967 14.1. IPv6 Router Alert Option - RFC 2711 969 The IPv6 Router Alert Option [RFC2711] is an optional IPv6 Hop-by-Hop 970 Header that is used in conjunction with some protocols (e.g., RSVP 971 [RFC2205] or Multicast Listener Discovery (MLD) [RFC2710]). The 972 Router Alert option will need to be implemented whenever protocols 973 that mandate its usage (e.g., MLD) are implemented. See 974 Section 5.11. 976 14.2. Neighbor Discovery for IPv6 - RFC 4861 978 Sending Router Advertisements and processing Router Solicitations 979 MUST be supported. 981 Section 7 of [RFC6275] includes some mobility-specific extensions to 982 Neighbor Discovery. Routers SHOULD implement Sections 7.3 and 7.5, 983 even if they do not implement Home Agent functionality. 985 14.3. Stateful Address Autoconfiguration (DHCPv6) - RFC 3315 987 A single DHCP server ([RFC3315] or [RFC4862]) can provide 988 configuration information to devices directly attached to a shared 989 link, as well as to devices located elsewhere within a site. 990 Communication between a client and a DHCP server located on different 991 links requires the use of DHCP relay agents on routers. 993 In simple deployments, consisting of a single router and either a 994 single LAN or multiple LANs attached to the single router, together 995 with a WAN connection, a DHCP server embedded within the router is 996 one common deployment scenario (e.g., [RFC7084]). However, there is 997 no need for relay agents in such scenarios. 999 In more complex deployment scenarios, such as within enterprise or 1000 service provider networks, the use of DHCP requires some level of 1001 configuration, in order to configure relay agents, DHCP servers, etc. 1002 In such environments, the DHCP server might even be run on a 1003 traditional server, rather than as part of a router. 1005 Because of the wide range of deployment scenarios, support for DHCP 1006 server functionality on routers is optional. However, routers 1007 targeted for deployment within more complex scenarios (as described 1008 above) SHOULD support relay agent functionality. Note that "Basic 1009 Requirements for IPv6 Customer Edge Routers" [RFC7084] requires 1010 implementation of a DHCPv6 server function in IPv6 Customer Edge (CE) 1011 routers. 1013 14.4. IPv6 Prefix Length Recommendation for Forwarding - BCP 198 1015 Forwarding nodes MUST conform to BCP 198 [RFC7608] and thus IPv6 1016 implementations of nodes that may forward packets MUST conform to the 1017 rules specified in Section 5.1 of [RFC4632]. 1019 15. Constrained Devices 1021 The target for this document is general IPv6 nodes. In the case of 1022 constrained nodes, with limited CPU, memory, bandwidth or power, 1023 support for certain IPv6 functionality may need to be considered due 1024 to those limitations. The requirements of this document are 1025 RECOMMENDED for all nodes, including constrained nodes, but 1026 compromises may need to be made in certain cases. Where such 1027 compromises are made, the interoperability of devices should be 1028 strongly considered, paticularly where this may impact other nodes on 1029 the same link, e.g., only supporting MLDv1 will affect other nodes. 1031 The IETF 6LowPAN (IPv6 over Low Power LWPAN) WG defined six RFCs, 1032 including a general overview and problem statement ([RFC4919], the 1033 means by which IPv6 packets are transmitted over IEEE 802.15.4 1034 networks [RFC4944] and ND optimisations for that medium [RFC6775]. 1036 If an IPv6 node is concerned about the impact of IPv6 message power 1037 consumption, it MAY want to implement the recommendations in 1038 [RFC7772]. 1040 16. Network Management 1042 Network management MAY be supported by IPv6 nodes. However, for IPv6 1043 nodes that are embedded devices, network management may be the only 1044 possible way of controlling these nodes. 1046 A node supporting network management SHOULD support NETCONF [RFC6241] 1047 and SNMP configuration [RFC3411]. 1049 16.1. Management Information Base (MIB) Modules 1051 IPv6 MIB have been updated since the last release of the document, 1052 [RFC8096] obseletes several MIBs, the nodes need to not support any 1053 longer. 1055 The following two MIB modules SHOULD be supported by nodes that 1056 support a Simple Network Management Protocol (SNMP) agent. 1058 16.1.1. IP Forwarding Table MIB 1060 The IP Forwarding Table MIB [RFC4292] SHOULD be supported by nodes 1061 that support an SNMP agent. 1063 16.1.2. Management Information Base for the Internet Protocol (IP) 1065 The IP MIB [RFC4293] SHOULD be supported by nodes that support an 1066 SNMP agent. 1068 16.2. YANG Data Models 1070 The following YANG data models SHOULD be supported by nodes that 1071 support a NETCONF agent. 1073 16.2.1. IP Management YANG Model 1075 The IP Management YANG Model [RFC7277] SHOULD be supported by nodes 1076 that support NETCONF. 1078 16.2.2. System Management YANG Model 1080 The System Management YANG Model [RFC7317] SHOULD be supported by 1081 nodes that support NETCONF. 1083 16.2.3. System Management YANG Model 1085 The Interface Management YANG Model [RFC7223] SHOULD be supported by 1086 nodes that support NETCONF. 1088 17. Security Considerations 1090 This document does not directly affect the security of the Internet, 1091 beyond the security considerations associated with the individual 1092 protocols. 1094 Security is also discussed in Section 13 above. 1096 18. IANA Considerations 1098 This document does not require any IANA actions. 1100 19. Authors and Acknowledgments 1102 19.1. Authors and Acknowledgments (Current Document) 1104 For this version of the IPv6 Node Requirements document, the authors 1105 would like to thank Brian Carpenter, Dave Thaler, Tom Herbert, Erik 1106 Kline, Mohamed Boucadair, and Michayla Newcombe for their 1107 contributions. 1109 19.2. Authors and Acknowledgments from RFC 6434 1111 Ed Jankiewicz and Thomas Narten were named authors of the previous 1112 iteration of this document, RFC6434. 1114 For this version of the document, the authors thanked Hitoshi Asaeda, 1115 Brian Carpenter, Tim Chown, Ralph Droms, Sheila Frankel, Sam Hartman, 1116 Bob Hinden, Paul Hoffman, Pekka Savola, Yaron Sheffer, and Dave 1117 Thaler. 1119 19.3. Authors and Acknowledgments from RFC 4294 1121 The original version of this document (RFC 4294) was written by the 1122 IPv6 Node Requirements design team: 1124 Jari Arkko 1125 jari.arkko@ericsson.com 1127 Marc Blanchet 1128 marc.blanchet@viagenie.qc.ca 1130 Samita Chakrabarti 1131 samita.chakrabarti@eng.sun.com 1133 Alain Durand 1134 alain.durand@sun.com 1136 Gerard Gastaud 1137 gerard.gastaud@alcatel.fr 1139 Jun-ichiro Itojun Hagino 1140 itojun@iijlab.net 1142 Atsushi Inoue 1143 inoue@isl.rdc.toshiba.co.jp 1145 Masahiro Ishiyama 1146 masahiro@isl.rdc.toshiba.co.jp 1148 John Loughney 1149 john.loughney@nokia.com 1151 Rajiv Raghunarayan 1152 raraghun@cisco.com 1153 Shoichi Sakane 1154 shouichi.sakane@jp.yokogawa.com 1156 Dave Thaler 1157 dthaler@windows.microsoft.com 1159 Juha Wiljakka 1160 juha.wiljakka@Nokia.com 1162 The authors would like to thank Ran Atkinson, Jim Bound, Brian 1163 Carpenter, Ralph Droms, Christian Huitema, Adam Machalek, Thomas 1164 Narten, Juha Ollila, and Pekka Savola for their comments. Thanks to 1165 Mark Andrews for comments and corrections on DNS text. Thanks to 1166 Alfred Hoenes for tracking the updates to various RFCs. 1168 20. Appendix: Changes from RFC 6434 1170 There have been many editorial clarifications as well as significant 1171 additions and updates. While this section highlights some of the 1172 changes, readers should not rely on this section for a comprehensive 1173 list of all changes. 1175 1. Restructured sections 1177 2. Added 6LoWPAN to link layers. 1179 3. Removed DOD IPv6 Profile updates. 1181 4. Updated to state MLDv2 support is a MUST. 1183 5. Require DNS RA Options, RFC8106 is a MUST. 1185 6. Added section on constrained devices. 1187 7. Added text on RFC7934, address availability to hosts. 1189 8. Added text on RFC7844, anonymity profiles for DHCPv6 clients. 1191 9. mDNS and DNS-SD added. 1193 10. Added RFC8028 as a SHOULD. 1195 11. Added ECN RFC3168 as a SHOULD. 1197 12. Added reference to RFC7123. 1199 13. Removed Jumbograms RFC2675. 1201 14. Updated RFC2460 to 8200. 1203 15. Updated RFC1981 to 8201. 1205 16. Updated RFC1981 to 8201. 1207 17. Updated RFC7321 to 8221. 1209 18. Updated RFC4307 to 8247. 1211 19. Added RFC7772 for power comsumptions 1213 20. Added why /64 boundries - RFC 7421 1215 21. Added a Unique IPv6 PRefix per Host 1216 22. Clarified RFC7066 was snapshot for 3GPP 1218 23. Updated 4191 as a MUST, SHOULD for Type C Host. 1220 24. Removed IPv6 over ATM 1222 25. Added a note in Section 6.6 for RFC6724 Section 5.5/ 1224 26. Added MUST for BCP 198 1226 27. Added reference to draft-ietf-v6ops-ipv6rtr-reqs 1228 28. Added reference to RFC8064 1230 29. Made RFC8028 normative 1232 30. Added text on protection from excessive EH options 1234 31. Added text on dangers of 1280 MTU UDP, esp. wrt DNS traffic 1236 21. Appendix: Changes from RFC 4294 1238 There have been many editorial clarifications as well as significant 1239 additions and updates. While this section highlights some of the 1240 changes, readers should not rely on this section for a comprehensive 1241 list of all changes. 1243 1. Updated the Introduction to indicate that this document is an 1244 applicability statement and is aimed at general nodes. 1246 2. Significantly updated the section on Mobility protocols, adding 1247 references and downgrading previous SHOULDs to MAYs. 1249 3. Changed Sub-IP Layer section to just list relevant RFCs, and 1250 added some more RFCs. 1252 4. Added section on SEND (it is a MAY). 1254 5. Revised section on Privacy Extensions [RFC4941] to add more 1255 nuance to recommendation. 1257 6. Completely revised IPsec/IKEv2 section, downgrading overall 1258 recommendation to a SHOULD. 1260 7. Upgraded recommendation of DHCPv6 to SHOULD. 1262 8. Added background section on DHCP versus RA options, added SHOULD 1263 recommendation for DNS configuration via RAs (RFC6106), and 1264 cleaned up DHCP recommendations. 1266 9. Added recommendation that routers implement Sections 7.3 and 7.5 1267 of [RFC6275]. 1269 10. Added pointer to subnet clarification document [RFC5942]. 1271 11. Added text that "IPv6 Host-to-Router Load Sharing" [RFC4311] 1272 SHOULD be implemented. 1274 12. Added reference to [RFC5722] (Overlapping Fragments), and made 1275 it a MUST to implement. 1277 13. Made "A Recommendation for IPv6 Address Text Representation" 1278 [RFC5952] a SHOULD. 1280 14. Removed mention of "DNAME" from the discussion about [RFC3363]. 1282 15. Numerous updates to reflect newer versions of IPv6 documents, 1283 including [RFC4443], [RFC4291], [RFC3596], and [RFC4213]. 1285 16. Removed discussion of "Managed" and "Other" flags in RAs. There 1286 is no consensus at present on how to process these flags, and 1287 discussion of their semantics was removed in the most recent 1288 update of Stateless Address Autoconfiguration [RFC4862]. 1290 17. Added many more references to optional IPv6 documents. 1292 18. Made "A Recommendation for IPv6 Address Text Representation" 1293 [RFC5952] a SHOULD. 1295 19. Added reference to [RFC5722] (Overlapping Fragments), and made 1296 it a MUST to implement. 1298 20. Updated MLD section to include reference to Lightweight MLD 1299 [RFC5790]. 1301 21. Added SHOULD recommendation for "Default Router Preferences and 1302 More-Specific Routes" [RFC4191]. 1304 22. Made "IPv6 Flow Label Specification" [RFC6437] a SHOULD. 1306 22. References 1308 22.1. Normative References 1310 [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", 1311 STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, 1312 . 1314 [RFC1035] Mockapetris, P., "Domain names - implementation and 1315 specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, 1316 November 1987, . 1318 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1319 Requirement Levels", BCP 14, RFC 2119, 1320 DOI 10.17487/RFC2119, March 1997, 1321 . 1323 [RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast 1324 Listener Discovery (MLD) for IPv6", RFC 2710, 1325 DOI 10.17487/RFC2710, October 1999, 1326 . 1328 [RFC2711] Partridge, C. and A. Jackson, "IPv6 Router Alert Option", 1329 RFC 2711, DOI 10.17487/RFC2711, October 1999, 1330 . 1332 [RFC3168] Ramakrishnan, K., Floyd, S., and D. Black, "The Addition 1333 of Explicit Congestion Notification (ECN) to IP", 1334 RFC 3168, DOI 10.17487/RFC3168, September 2001, 1335 . 1337 [RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins, 1338 C., and M. Carney, "Dynamic Host Configuration Protocol 1339 for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July 1340 2003, . 1342 [RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An 1343 Architecture for Describing Simple Network Management 1344 Protocol (SNMP) Management Frameworks", STD 62, RFC 3411, 1345 DOI 10.17487/RFC3411, December 2002, 1346 . 1348 [RFC3596] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi, 1349 "DNS Extensions to Support IP Version 6", STD 88, 1350 RFC 3596, DOI 10.17487/RFC3596, October 2003, 1351 . 1353 [RFC3736] Droms, R., "Stateless Dynamic Host Configuration Protocol 1354 (DHCP) Service for IPv6", RFC 3736, DOI 10.17487/RFC3736, 1355 April 2004, . 1357 [RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener 1358 Discovery Version 2 (MLDv2) for IPv6", RFC 3810, 1359 DOI 10.17487/RFC3810, June 2004, 1360 . 1362 [RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S. 1363 Rose, "DNS Security Introduction and Requirements", 1364 RFC 4033, DOI 10.17487/RFC4033, March 2005, 1365 . 1367 [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. 1368 Rose, "Resource Records for the DNS Security Extensions", 1369 RFC 4034, DOI 10.17487/RFC4034, March 2005, 1370 . 1372 [RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S. 1373 Rose, "Protocol Modifications for the DNS Security 1374 Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005, 1375 . 1377 [RFC4213] Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms 1378 for IPv6 Hosts and Routers", RFC 4213, 1379 DOI 10.17487/RFC4213, October 2005, 1380 . 1382 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 1383 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 1384 2006, . 1386 [RFC4292] Haberman, B., "IP Forwarding Table MIB", RFC 4292, 1387 DOI 10.17487/RFC4292, April 2006, 1388 . 1390 [RFC4293] Routhier, S., Ed., "Management Information Base for the 1391 Internet Protocol (IP)", RFC 4293, DOI 10.17487/RFC4293, 1392 April 2006, . 1394 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 1395 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 1396 December 2005, . 1398 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 1399 RFC 4303, DOI 10.17487/RFC4303, December 2005, 1400 . 1402 [RFC4311] Hinden, R. and D. Thaler, "IPv6 Host-to-Router Load 1403 Sharing", RFC 4311, DOI 10.17487/RFC4311, November 2005, 1404 . 1406 [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet 1407 Control Message Protocol (ICMPv6) for the Internet 1408 Protocol Version 6 (IPv6) Specification", STD 89, 1409 RFC 4443, DOI 10.17487/RFC4443, March 2006, 1410 . 1412 [RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for 1413 IP", RFC 4607, DOI 10.17487/RFC4607, August 2006, 1414 . 1416 [RFC4632] Fuller, V. and T. Li, "Classless Inter-domain Routing 1417 (CIDR): The Internet Address Assignment and Aggregation 1418 Plan", BCP 122, RFC 4632, DOI 10.17487/RFC4632, August 1419 2006, . 1421 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 1422 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 1423 DOI 10.17487/RFC4861, September 2007, 1424 . 1426 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 1427 Address Autoconfiguration", RFC 4862, 1428 DOI 10.17487/RFC4862, September 2007, 1429 . 1431 [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy 1432 Extensions for Stateless Address Autoconfiguration in 1433 IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007, 1434 . 1436 [RFC5095] Abley, J., Savola, P., and G. Neville-Neil, "Deprecation 1437 of Type 0 Routing Headers in IPv6", RFC 5095, 1438 DOI 10.17487/RFC5095, December 2007, 1439 . 1441 [RFC5453] Krishnan, S., "Reserved IPv6 Interface Identifiers", 1442 RFC 5453, DOI 10.17487/RFC5453, February 2009, 1443 . 1445 [RFC5722] Krishnan, S., "Handling of Overlapping IPv6 Fragments", 1446 RFC 5722, DOI 10.17487/RFC5722, December 2009, 1447 . 1449 [RFC5790] Liu, H., Cao, W., and H. Asaeda, "Lightweight Internet 1450 Group Management Protocol Version 3 (IGMPv3) and Multicast 1451 Listener Discovery Version 2 (MLDv2) Protocols", RFC 5790, 1452 DOI 10.17487/RFC5790, February 2010, 1453 . 1455 [RFC5942] Singh, H., Beebee, W., and E. Nordmark, "IPv6 Subnet 1456 Model: The Relationship between Links and Subnet 1457 Prefixes", RFC 5942, DOI 10.17487/RFC5942, July 2010, 1458 . 1460 [RFC5952] Kawamura, S. and M. Kawashima, "A Recommendation for IPv6 1461 Address Text Representation", RFC 5952, 1462 DOI 10.17487/RFC5952, August 2010, 1463 . 1465 [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., 1466 and A. Bierman, Ed., "Network Configuration Protocol 1467 (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, 1468 . 1470 [RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme, 1471 "IPv6 Flow Label Specification", RFC 6437, 1472 DOI 10.17487/RFC6437, November 2011, 1473 . 1475 [RFC6564] Krishnan, S., Woodyatt, J., Kline, E., Hoagland, J., and 1476 M. Bhatia, "A Uniform Format for IPv6 Extension Headers", 1477 RFC 6564, DOI 10.17487/RFC6564, April 2012, 1478 . 1480 [RFC6724] Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown, 1481 "Default Address Selection for Internet Protocol Version 6 1482 (IPv6)", RFC 6724, DOI 10.17487/RFC6724, September 2012, 1483 . 1485 [RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762, 1486 DOI 10.17487/RFC6762, February 2013, 1487 . 1489 [RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service 1490 Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013, 1491 . 1493 [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. 1494 Bormann, "Neighbor Discovery Optimization for IPv6 over 1495 Low-Power Wireless Personal Area Networks (6LoWPANs)", 1496 RFC 6775, DOI 10.17487/RFC6775, November 2012, 1497 . 1499 [RFC6891] Damas, J., Graff, M., and P. Vixie, "Extension Mechanisms 1500 for DNS (EDNS(0))", STD 75, RFC 6891, 1501 DOI 10.17487/RFC6891, April 2013, 1502 . 1504 [RFC6946] Gont, F., "Processing of IPv6 "Atomic" Fragments", 1505 RFC 6946, DOI 10.17487/RFC6946, May 2013, 1506 . 1508 [RFC7045] Carpenter, B. and S. Jiang, "Transmission and Processing 1509 of IPv6 Extension Headers", RFC 7045, 1510 DOI 10.17487/RFC7045, December 2013, 1511 . 1513 [RFC7048] Nordmark, E. and I. Gashinsky, "Neighbor Unreachability 1514 Detection Is Too Impatient", RFC 7048, 1515 DOI 10.17487/RFC7048, January 2014, 1516 . 1518 [RFC7112] Gont, F., Manral, V., and R. Bonica, "Implications of 1519 Oversized IPv6 Header Chains", RFC 7112, 1520 DOI 10.17487/RFC7112, January 2014, 1521 . 1523 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 1524 Interface Identifiers with IPv6 Stateless Address 1525 Autoconfiguration (SLAAC)", RFC 7217, 1526 DOI 10.17487/RFC7217, April 2014, 1527 . 1529 [RFC7223] Bjorklund, M., "A YANG Data Model for Interface 1530 Management", RFC 7223, DOI 10.17487/RFC7223, May 2014, 1531 . 1533 [RFC7277] Bjorklund, M., "A YANG Data Model for IP Management", 1534 RFC 7277, DOI 10.17487/RFC7277, June 2014, 1535 . 1537 [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. 1538 Kivinen, "Internet Key Exchange Protocol Version 2 1539 (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October 1540 2014, . 1542 [RFC7317] Bierman, A. and M. Bjorklund, "A YANG Data Model for 1543 System Management", RFC 7317, DOI 10.17487/RFC7317, August 1544 2014, . 1546 [RFC7527] Asati, R., Singh, H., Beebee, W., Pignataro, C., Dart, E., 1547 and W. George, "Enhanced Duplicate Address Detection", 1548 RFC 7527, DOI 10.17487/RFC7527, April 2015, 1549 . 1551 [RFC7559] Krishnan, S., Anipko, D., and D. Thaler, "Packet-Loss 1552 Resiliency for Router Solicitations", RFC 7559, 1553 DOI 10.17487/RFC7559, May 2015, 1554 . 1556 [RFC7608] Boucadair, M., Petrescu, A., and F. Baker, "IPv6 Prefix 1557 Length Recommendation for Forwarding", BCP 198, RFC 7608, 1558 DOI 10.17487/RFC7608, July 2015, 1559 . 1561 [RFC7739] Gont, F., "Security Implications of Predictable Fragment 1562 Identification Values", RFC 7739, DOI 10.17487/RFC7739, 1563 February 2016, . 1565 [RFC8021] Gont, F., Liu, W., and T. Anderson, "Generation of IPv6 1566 Atomic Fragments Considered Harmful", RFC 8021, 1567 DOI 10.17487/RFC8021, January 2017, 1568 . 1570 [RFC8028] Baker, F. and B. Carpenter, "First-Hop Router Selection by 1571 Hosts in a Multi-Prefix Network", RFC 8028, 1572 DOI 10.17487/RFC8028, November 2016, 1573 . 1575 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 1576 "Recommendation on Stable IPv6 Interface Identifiers", 1577 RFC 8064, DOI 10.17487/RFC8064, February 2017, 1578 . 1580 [RFC8106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli, 1581 "IPv6 Router Advertisement Options for DNS Configuration", 1582 RFC 8106, DOI 10.17487/RFC8106, March 2017, 1583 . 1585 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1586 (IPv6) Specification", STD 86, RFC 8200, 1587 DOI 10.17487/RFC8200, July 2017, 1588 . 1590 [RFC8201] McCann, J., Deering, S., Mogul, J., and R. Hinden, Ed., 1591 "Path MTU Discovery for IP version 6", STD 87, RFC 8201, 1592 DOI 10.17487/RFC8201, July 2017, 1593 . 1595 [RFC8221] Wouters, P., Migault, D., Mattsson, J., Nir, Y., and T. 1596 Kivinen, "Cryptographic Algorithm Implementation 1597 Requirements and Usage Guidance for Encapsulating Security 1598 Payload (ESP) and Authentication Header (AH)", RFC 8221, 1599 DOI 10.17487/RFC8221, October 2017, 1600 . 1602 [RFC8247] Nir, Y., Kivinen, T., Wouters, P., and D. Migault, 1603 "Algorithm Implementation Requirements and Usage Guidance 1604 for the Internet Key Exchange Protocol Version 2 (IKEv2)", 1605 RFC 8247, DOI 10.17487/RFC8247, September 2017, 1606 . 1608 22.2. Informative References 1610 [I-D.ietf-v6ops-unique-ipv6-prefix-per-host] 1611 Brzozowski, J. and G. Velde, "Unique IPv6 Prefix Per 1612 Host", draft-ietf-v6ops-unique-ipv6-prefix-per-host-13 1613 (work in progress), October 2017. 1615 [I-D.ietf-v6ops-ipv6rtr-reqs] 1616 Kahn, Z., Brzozowski, J., and R. White, "Requirements for 1617 IPv6 Routers", draft-ietf-v6ops-ipv6rtr-reqs-00 (work in 1618 progress), May 2017. 1620 [RFC0793] Postel, J., "Transmission Control Protocol", STD 7, 1621 RFC 793, DOI 10.17487/RFC0793, September 1981, 1622 . 1624 [RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S. 1625 Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 1626 Functional Specification", RFC 2205, DOI 10.17487/RFC2205, 1627 September 1997, . 1629 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 1630 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 1631 . 1633 [RFC2491] Armitage, G., Schulter, P., Jork, M., and G. Harter, "IPv6 1634 over Non-Broadcast Multiple Access (NBMA) networks", 1635 RFC 2491, DOI 10.17487/RFC2491, January 1999, 1636 . 1638 [RFC2590] Conta, A., Malis, A., and M. Mueller, "Transmission of 1639 IPv6 Packets over Frame Relay Networks Specification", 1640 RFC 2590, DOI 10.17487/RFC2590, May 1999, 1641 . 1643 [RFC3146] Fujisawa, K. and A. Onoe, "Transmission of IPv6 Packets 1644 over IEEE 1394 Networks", RFC 3146, DOI 10.17487/RFC3146, 1645 October 2001, . 1647 [RFC3363] Bush, R., Durand, A., Fink, B., Gudmundsson, O., and T. 1648 Hain, "Representing Internet Protocol version 6 (IPv6) 1649 Addresses in the Domain Name System (DNS)", RFC 3363, 1650 DOI 10.17487/RFC3363, August 2002, 1651 . 1653 [RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J., and W. 1654 Stevens, "Basic Socket Interface Extensions for IPv6", 1655 RFC 3493, DOI 10.17487/RFC3493, February 2003, 1656 . 1658 [RFC3542] Stevens, W., Thomas, M., Nordmark, E., and T. Jinmei, 1659 "Advanced Sockets Application Program Interface (API) for 1660 IPv6", RFC 3542, DOI 10.17487/RFC3542, May 2003, 1661 . 1663 [RFC3678] Thaler, D., Fenner, B., and B. Quinn, "Socket Interface 1664 Extensions for Multicast Source Filters", RFC 3678, 1665 DOI 10.17487/RFC3678, January 2004, 1666 . 1668 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 1669 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 1670 2011, . 1672 [RFC3776] Arkko, J., Devarapalli, V., and F. Dupont, "Using IPsec to 1673 Protect Mobile IPv6 Signaling Between Mobile Nodes and 1674 Home Agents", RFC 3776, DOI 10.17487/RFC3776, June 2004, 1675 . 1677 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 1678 "SEcure Neighbor Discovery (SEND)", RFC 3971, 1679 DOI 10.17487/RFC3971, March 2005, 1680 . 1682 [RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)", 1683 RFC 3972, DOI 10.17487/RFC3972, March 2005, 1684 . 1686 [RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and 1687 More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191, 1688 November 2005, . 1690 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 1691 DOI 10.17487/RFC4302, December 2005, 1692 . 1694 [RFC4338] DeSanti, C., Carlson, C., and R. Nixon, "Transmission of 1695 IPv6, IPv4, and Address Resolution Protocol (ARP) Packets 1696 over Fibre Channel", RFC 4338, DOI 10.17487/RFC4338, 1697 January 2006, . 1699 [RFC4380] Huitema, C., "Teredo: Tunneling IPv6 over UDP through 1700 Network Address Translations (NATs)", RFC 4380, 1701 DOI 10.17487/RFC4380, February 2006, 1702 . 1704 [RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD) 1705 for IPv6", RFC 4429, DOI 10.17487/RFC4429, April 2006, 1706 . 1708 [RFC4584] Chakrabarti, S. and E. Nordmark, "Extension to Sockets API 1709 for Mobile IPv6", RFC 4584, DOI 10.17487/RFC4584, July 1710 2006, . 1712 [RFC4821] Mathis, M. and J. Heffner, "Packetization Layer Path MTU 1713 Discovery", RFC 4821, DOI 10.17487/RFC4821, March 2007, 1714 . 1716 [RFC4877] Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with 1717 IKEv2 and the Revised IPsec Architecture", RFC 4877, 1718 DOI 10.17487/RFC4877, April 2007, 1719 . 1721 [RFC4884] Bonica, R., Gan, D., Tappan, D., and C. Pignataro, 1722 "Extended ICMP to Support Multi-Part Messages", RFC 4884, 1723 DOI 10.17487/RFC4884, April 2007, 1724 . 1726 [RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6 1727 over Low-Power Wireless Personal Area Networks (6LoWPANs): 1728 Overview, Assumptions, Problem Statement, and Goals", 1729 RFC 4919, DOI 10.17487/RFC4919, August 2007, 1730 . 1732 [RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, 1733 "Transmission of IPv6 Packets over IEEE 802.15.4 1734 Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007, 1735 . 1737 [RFC5014] Nordmark, E., Chakrabarti, S., and J. Laganier, "IPv6 1738 Socket API for Source Address Selection", RFC 5014, 1739 DOI 10.17487/RFC5014, September 2007, 1740 . 1742 [RFC5072] Varada, S., Ed., Haskins, D., and E. Allen, "IP Version 6 1743 over PPP", RFC 5072, DOI 10.17487/RFC5072, September 2007, 1744 . 1746 [RFC5121] Patil, B., Xia, F., Sarikaya, B., Choi, JH., and S. 1747 Madanapalli, "Transmission of IPv6 via the IPv6 1748 Convergence Sublayer over IEEE 802.16 Networks", RFC 5121, 1749 DOI 10.17487/RFC5121, February 2008, 1750 . 1752 [RFC5555] Soliman, H., Ed., "Mobile IPv6 Support for Dual Stack 1753 Hosts and Routers", RFC 5555, DOI 10.17487/RFC5555, June 1754 2009, . 1756 [RFC6563] Jiang, S., Conrad, D., and B. Carpenter, "Moving A6 to 1757 Historic Status", RFC 6563, DOI 10.17487/RFC6563, March 1758 2012, . 1760 [RFC7066] Korhonen, J., Ed., Arkko, J., Ed., Savolainen, T., and S. 1761 Krishnan, "IPv6 for Third Generation Partnership Project 1762 (3GPP) Cellular Hosts", RFC 7066, DOI 10.17487/RFC7066, 1763 November 2013, . 1765 [RFC7084] Singh, H., Beebee, W., Donley, C., and B. Stark, "Basic 1766 Requirements for IPv6 Customer Edge Routers", RFC 7084, 1767 DOI 10.17487/RFC7084, November 2013, 1768 . 1770 [RFC7123] Gont, F. and W. Liu, "Security Implications of IPv6 on 1771 IPv4 Networks", RFC 7123, DOI 10.17487/RFC7123, February 1772 2014, . 1774 [RFC7278] Byrne, C., Drown, D., and A. Vizdal, "Extending an IPv6 1775 /64 Prefix from a Third Generation Partnership Project 1776 (3GPP) Mobile Interface to a LAN Link", RFC 7278, 1777 DOI 10.17487/RFC7278, June 2014, 1778 . 1780 [RFC7421] Carpenter, B., Ed., Chown, T., Gont, F., Jiang, S., 1781 Petrescu, A., and A. Yourtchenko, "Analysis of the 64-bit 1782 Boundary in IPv6 Addressing", RFC 7421, 1783 DOI 10.17487/RFC7421, January 2015, 1784 . 1786 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 1787 Considerations for IPv6 Address Generation Mechanisms", 1788 RFC 7721, DOI 10.17487/RFC7721, March 2016, 1789 . 1791 [RFC7772] Yourtchenko, A. and L. Colitti, "Reducing Energy 1792 Consumption of Router Advertisements", BCP 202, RFC 7772, 1793 DOI 10.17487/RFC7772, February 2016, 1794 . 1796 [RFC7844] Huitema, C., Mrugalski, T., and S. Krishnan, "Anonymity 1797 Profiles for DHCP Clients", RFC 7844, 1798 DOI 10.17487/RFC7844, May 2016, 1799 . 1801 [RFC7934] Colitti, L., Cerf, V., Cheshire, S., and D. Schinazi, 1802 "Host Address Availability Recommendations", BCP 204, 1803 RFC 7934, DOI 10.17487/RFC7934, July 2016, 1804 . 1806 [RFC8096] Fenner, B., "The IPv6-Specific MIB Modules Are Obsolete", 1807 RFC 8096, DOI 10.17487/RFC8096, April 2017, 1808 . 1810 [POSIX] IEEE, "IEEE Std. 1003.1-2008 Standard for Information 1811 Technology -- Portable Operating System Interface (POSIX), 1812 ISO/IEC 9945:2009", . 1814 [USGv6] National Institute of Standards and Technology, "A Profile 1815 for IPv6 in the U.S. Government - Version 1.0", July 2008, 1816 . 1818 Authors' Addresses 1820 Tim Chown 1821 Jisc 1822 Lumen House, Library Avenue 1823 Harwell Oxford, Didcot OX11 0SG 1824 United Kingdom 1826 Email: tim.chown@jisc.ac.uk 1827 John Loughney 1828 Intel 1829 Santa Clara, CA 1830 USA 1832 Email: john.loughney@gmail.com 1834 Timothy Winters 1835 University of New Hampshire 1836 InterOperability Laboratory 1837 Durham NH 1838 United States 1840 Email: twinters@iol.unh.edu