idnits 2.17.1 draft-ietf-v6ops-6204bis-07.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (March 8, 2012) is 4430 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- == Outdated reference: A later version (-29) exists of draft-ietf-pcp-base-23 ** Obsolete normative reference: RFC 3315 (Obsoleted by RFC 8415) ** Obsolete normative reference: RFC 3633 (Obsoleted by RFC 8415) ** Obsolete normative reference: RFC 3736 (Obsoleted by RFC 8415) ** Obsolete normative reference: RFC 4242 (Obsoleted by RFC 8415) ** Obsolete normative reference: RFC 6434 (Obsoleted by RFC 8504) Summary: 5 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group H. Singh 3 Internet-Draft W. Beebee 4 Obsoletes: 6204 (if approved) Cisco Systems, Inc. 5 Intended status: Informational C. Donley 6 Expires: September 9, 2012 CableLabs 7 B. Stark 8 AT&T 9 O. Troan, Ed. 10 Cisco Systems, Inc. 11 March 8, 2012 13 Basic Requirements for IPv6 Customer Edge Routers 14 draft-ietf-v6ops-6204bis-07 16 Abstract 18 This document specifies requirements for an IPv6 Customer Edge (CE) 19 router. Specifically, the current version of this document focuses 20 on the basic provisioning of an IPv6 CE router and the provisioning 21 of IPv6 hosts attached to it. The document also covers IP transition 22 technologies. Two transition technologies in RFC 5969's 6rd and RFC 23 6333's DS-Lite. are covered in the document. The document obsoletes 24 RFC 6204, if approved. 26 Status of this Memo 28 This Internet-Draft is submitted in full conformance with the 29 provisions of BCP 78 and BCP 79. 31 Internet-Drafts are working documents of the Internet Engineering 32 Task Force (IETF). Note that other groups may also distribute 33 working documents as Internet-Drafts. The list of current Internet- 34 Drafts is at http://datatracker.ietf.org/drafts/current/. 36 Internet-Drafts are draft documents valid for a maximum of six months 37 and may be updated, replaced, or obsoleted by other documents at any 38 time. It is inappropriate to use Internet-Drafts as reference 39 material or to cite them other than as "work in progress." 41 This Internet-Draft will expire on September 9, 2012. 43 Copyright Notice 45 Copyright (c) 2012 IETF Trust and the persons identified as the 46 document authors. All rights reserved. 48 This document is subject to BCP 78 and the IETF Trust's Legal 49 Provisions Relating to IETF Documents 50 (http://trustee.ietf.org/license-info) in effect on the date of 51 publication of this document. Please review these documents 52 carefully, as they describe your rights and restrictions with respect 53 to this document. Code Components extracted from this document must 54 include Simplified BSD License text as described in Section 4.e of 55 the Trust Legal Provisions and are provided without warranty as 56 described in the Simplified BSD License. 58 Table of Contents 60 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 61 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 62 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 63 3. Architecture . . . . . . . . . . . . . . . . . . . . . . . . . 4 64 3.1. Current IPv4 End-User Network Architecture . . . . . . . . 4 65 3.2. IPv6 End-User Network Architecture . . . . . . . . . . . . 5 66 3.2.1. Local Communication . . . . . . . . . . . . . . . . . 6 67 4. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 7 68 4.1. General Requirements . . . . . . . . . . . . . . . . . . . 7 69 4.2. WAN-Side Configuration . . . . . . . . . . . . . . . . . . 7 70 4.3. LAN-Side Configuration . . . . . . . . . . . . . . . . . . 11 71 4.4. Transition Technologies Support . . . . . . . . . . . . . 13 72 4.4.1. 6rd . . . . . . . . . . . . . . . . . . . . . . . . . 13 73 4.4.2. Dual-Stack Lite (DS-Lite) . . . . . . . . . . . . . . 14 74 4.5. Security Considerations . . . . . . . . . . . . . . . . . 14 75 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 76 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 15 77 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 16 78 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 79 8.1. Normative References . . . . . . . . . . . . . . . . . . . 16 80 8.2. Informative References . . . . . . . . . . . . . . . . . . 18 81 Appendix A. Changes from RFC 6204 . . . . . . . . . . . . . . . . 19 82 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20 84 1. Introduction 86 This document defines basic IPv6 features for a residential or small- 87 office router, referred to as an IPv6 CE router. Typically, these 88 routers also support IPv4. 90 Mixed environments of dual-stack hosts and IPv6-only hosts (behind 91 the CE router) can be more complex if the IPv6-only devices are using 92 a translator to access IPv4 servers [RFC6144]. Support for such 93 mixed environments is not in scope of this document. 95 This document specifies how an IPv6 CE router automatically 96 provisions its WAN interface, acquires address space for provisioning 97 of its LAN interfaces, and fetches other configuration information 98 from the service provider network. Automatic provisioning of more 99 complex topology than a single router with multiple LAN interfaces is 100 out of scope for this document. 102 See [RFC4779] for a discussion of options available for deploying 103 IPv6 in service provider access networks. 105 The document also covers IP transition technologies. Two transition 106 technologies in 6rd [RFC5969] and DS-Lite [RFC6333] are covered in 107 the document. At the time of writing this document these were the 108 only two transition technologies available in RFC form to be included 109 in this document. 111 1.1. Requirements Language 113 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 114 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 115 document are to be interpreted as described in RFC 2119 [RFC2119]. 117 2. Terminology 119 End-User Network one or more links attached to the IPv6 CE 120 router that connect IPv6 hosts. 122 IPv6 Customer Edge Router a node intended for home or small-office 123 use that forwards IPv6 packets not 124 explicitly addressed to itself. The IPv6 125 CE router connects the end-user network to 126 a service provider network. 128 IPv6 Host any device implementing an IPv6 stack 129 receiving IPv6 connectivity through the 130 IPv6 CE router. 132 LAN Interface an IPv6 CE router's attachment to a link in 133 the end-user network. Examples are 134 Ethernet (simple or bridged), 802.11 135 wireless, or other LAN technologies. An 136 IPv6 CE router may have one or more 137 network-layer LAN interfaces. 139 Service Provider an entity that provides access to the 140 Internet. In this document, a service 141 provider specifically offers Internet 142 access using IPv6, and may also offer IPv4 143 Internet access. The service provider can 144 provide such access over a variety of 145 different transport methods such as DSL, 146 cable, wireless, and others. 148 WAN Interface an IPv6 CE router's attachment to a link 149 used to provide connectivity to the service 150 provider network; example link technologies 151 include Ethernets (simple or bridged), PPP 152 links, Frame Relay, or ATM networks, as 153 well as Internet-layer (or higher-layer) 154 "tunnels", such as tunnels over IPv4 or 155 IPv6 itself. 157 3. Architecture 159 3.1. Current IPv4 End-User Network Architecture 161 An end-user network will likely support both IPv4 and IPv6. It is 162 not expected that an end-user will change their existing network 163 topology with the introduction of IPv6. There are some differences 164 in how IPv6 works and is provisioned; these differences have 165 implications for the network architecture. A typical IPv4 end-user 166 network consists of a "plug and play" router with NAT functionality 167 and a single link behind it, connected to the service provider 168 network. 170 A typical IPv4 NAT deployment by default blocks all incoming 171 connections. Opening of ports is typically allowed using a Universal 172 Plug and Play Internet Gateway Device (UPnP IGD) [UPnP-IGD] or some 173 other firewall control protocol. 175 Another consequence of using private address space in the end-user 176 network is that it provides stable addressing; i.e., it never changes 177 even when you change service providers, and the addresses are always 178 there even when the WAN interface is down or the customer edge router 179 has not yet been provisioned. 181 Rewriting addresses on the edge of the network also allows for some 182 rudimentary multihoming, even though using NATs for multihoming does 183 not preserve connections during a fail-over event [RFC4864]. 185 Many existing routers support dynamic routing, and advanced end-users 186 can build arbitrary, complex networks using manual configuration of 187 address prefixes combined with a dynamic routing protocol. 189 3.2. IPv6 End-User Network Architecture 191 The end-user network architecture for IPv6 should provide equivalent 192 or better capabilities and functionality than the current IPv4 193 architecture. 195 The end-user network is a stub network. Figure 1 illustrates the 196 model topology for the end-user network. 198 +-------+-------+ \ 199 | Service | \ 200 | Provider | | Service 201 | Router | | Provider 202 +-------+-------+ | network 203 | / 204 | Customer / 205 | Internet connection / 206 | 207 +------+--------+ \ 208 | IPv6 | \ 209 | Customer Edge | \ 210 | Router | / 211 +---+-------+-+-+ / 212 Network A | | Network B | End-User 213 ---+-------------+----+- --+--+-------------+--- | network(s) 214 | | | | \ 215 +----+-----+ +-----+----+ +----+-----+ +-----+----+ \ 216 |IPv6 Host | |IPv6 Host | | IPv6 Host| |IPv6 Host | / 217 | | | | | | | | / 218 +----------+ +-----+----+ +----------+ +----------+ / 220 Figure 1: An Example of a Typical End-User Network 222 This architecture describes the: 224 o Basic capabilities of an IPv6 CE router 226 o Provisioning of the WAN interface connecting to the service 227 provider 229 o Provisioning of the LAN interfaces 231 For IPv6 multicast traffic, the IPv6 CE router may act as a Multicast 232 Listener Discovery (MLD) proxy [RFC4605] and may support a dynamic 233 multicast routing protocol. 235 The IPv6 CE router may be manually configured in an arbitrary 236 topology with a dynamic routing protocol. Automatic provisioning and 237 configuration are described for a single IPv6 CE router only. 239 3.2.1. Local Communication 241 Link-local IPv6 addresses are used by hosts communicating on a single 242 link. Unique Local IPv6 Unicast Addresses (ULA's) [RFC4193] are used 243 by hosts communicating within the end-user network across multiple 244 links, but without requiring the application to use a globally 245 routable address. The IPv6 CE router defaults to acting as the 246 demarcation point between two networks by providing a ULA boundary, a 247 multicast zone boundary, and ingress and egress traffic filters. 249 At the time of this writing, several host implementations do not 250 handle the case where they have an IPv6 address configured and no 251 IPv6 connectivity, either because the address itself has a limited 252 topological reachability (e.g., ULA) or because the IPv6 CE router is 253 not connected to the IPv6 network on its WAN interface. To support 254 host implementations that do not handle multihoming in a multi-prefix 255 environment [MULTIHOMING-WITHOUT-NAT], the IPv6 CE router should not, 256 as detailed in the requirements below, advertise itself as a default 257 router on the LAN interface(s) when it does not have IPv6 258 connectivity on the WAN interface or when it is not provisioned with 259 IPv6 addresses. For local IPv6 communication, the mechanisms 260 specified in [RFC4191] are used. 262 ULA addressing is useful where the IPv6 CE router has multiple LAN 263 interfaces with hosts that need to communicate with each other. If 264 the IPv6 CE router has only a single LAN interface (IPv6 link), then 265 link-local addressing can be used instead. 267 Coexistence with IPv4 requires any IPv6 CE router(s) on the LAN to 268 conform to these recommendations, especially requirements ULA-5 and 269 L-4 below. 271 4. Requirements 273 4.1. General Requirements 275 The IPv6 CE router is responsible for implementing IPv6 routing; that 276 is, the IPv6 CE router must look up the IPv6 destination address in 277 its routing table to decide to which interface it should send the 278 packet. 280 In this role, the IPv6 CE router is responsible for ensuring that 281 traffic using its ULA addressing does not go out the WAN interface, 282 and does not originate from the WAN interface. 284 G-1: An IPv6 CE router is an IPv6 node according to the IPv6 Node 285 Requirements [RFC6434] specification. 287 G-2: The IPv6 CE router MUST implement ICMPv6 according to 288 [RFC4443]. In particular, point-to-point links MUST be handled 289 as described in Section 3.1 of [RFC4443]. 291 G-3: The IPv6 CE router MUST NOT forward any IPv6 traffic between 292 its LAN interface(s) and its WAN interface until the router has 293 successfully completed the IPv6 address and the delegated 294 prefix acquisition process. 296 G-4: By default, an IPv6 CE router that has no default router(s) on 297 its WAN interface MUST NOT advertise itself as an IPv6 default 298 router on its LAN interfaces. That is, the "Router Lifetime" 299 field is set to zero in all Router Advertisement messages it 300 originates [RFC4861]. 302 G-5: By default, if the IPv6 CE router is an advertising router and 303 loses its IPv6 default router(s) and/or detects loss of 304 connectivity on the WAN interface, it MUST explicitly 305 invalidate itself as an IPv6 default router on each of its 306 advertising interfaces by immediately transmitting one or more 307 Router Advertisement messages with the "Router Lifetime" field 308 set to zero [RFC4861]. 310 4.2. WAN-Side Configuration 312 The IPv6 CE router will need to support connectivity to one or more 313 access network architectures. This document describes an IPv6 CE 314 router that is not specific to any particular architecture or service 315 provider and that supports all commonly used architectures. 317 IPv6 Neighbor Discovery and DHCPv6 protocols operate over any type of 318 IPv6-supported link layer, and there is no need for a link-layer- 319 specific configuration protocol for IPv6 network-layer configuration 320 options as in, e.g., PPP IP Control Protocol (IPCP) for IPv4. This 321 section makes the assumption that the same mechanism will work for 322 any link layer, be it Ethernet, the Data Over Cable Service Interface 323 Specification (DOCSIS), PPP, or others. 325 WAN-side requirements: 327 W-1: When the router is attached to the WAN interface link, it MUST 328 act as an IPv6 host for the purposes of stateless [RFC4862] or 329 stateful [RFC3315] interface address assignment. 331 W-2: The IPv6 CE router MUST generate a link-local address and 332 finish Duplicate Address Detection according to [RFC4862] prior 333 to sending any Router Solicitations on the interface. The 334 source address used in the subsequent Router Solicitation MUST 335 be the link-local address on the WAN interface. 337 W-3: Absent other routing information, the IPv6 CE router MUST use 338 Router Discovery as specified in [RFC4861] to discover a 339 default router(s) and install default route(s) in its routing 340 table with the discovered router's address as the next hop. 342 W-4: The router MUST act as a requesting router for the purposes of 343 DHCPv6 prefix delegation ([RFC3633]). 345 W-5: The IPv6 CE router MUST use a persistent DHCP Unique Identifier 346 (DUID) for DHCPv6 messages. The DUID MUST NOT change between 347 network interface resets or IPv6 CE router reboots. 349 W-6: The WAN interface of the CE router SHOULD support an IPv4 PCP 350 client as specified in [I-D.ietf-pcp-base] for use by 351 applications on the CE Router. This document takes no position 352 on whether such functionality is enabled by default or 353 mechanisms by which users would configure the functionality. 355 Link-layer requirements: 357 WLL-1: If the WAN interface supports Ethernet encapsulation, then 358 the IPv6 CE router MUST support IPv6 over Ethernet [RFC2464]. 360 WLL-2: If the WAN interface supports PPP encapsulation, the IPv6 CE 361 router MUST support IPv6 over PPP [RFC5072]. 363 WLL-3: If the WAN interface supports PPP encapsulation, in a dual- 364 stack environment with IPCP and IPV6CP running over one PPP 365 logical channel, the Network Control Protocols (NCP's) MUST 366 be treated as independent of each other and start and 367 terminate independently. 369 Address assignment requirements: 371 WAA-1: The IPv6 CE router MUST support Stateless Address 372 Autoconfiguration (SLAAC) [RFC4862]. 374 WAA-2: The IPv6 CE router MUST follow the recommendations in Section 375 4 of [RFC5942], and in particular the handling of the L flag 376 in the Router Advertisement Prefix Information option. 378 WAA-3: The IPv6 CE router MUST support DHCPv6 [RFC3315] client 379 behavior. 381 WAA-4: The IPv6 CE router MUST be able to support the following 382 DHCPv6 options: IA_NA, Reconfigure Accept [RFC3315], and 383 DNS_SERVERS [RFC3646]. The IPv6 CE router SHOULD be able to 384 support the DNS Search List DNSSL option as specified in 385 [RFC3646]. 387 WAA-5: The IPv6 CE router SHOULD support the DHCPv6 Simple Network 388 Time Protocol (SNTP) option [RFC4075] and the Information 389 Refresh Time option [RFC4242]. 391 WAA-6: If the IPv6 CE router receives a Router Advertisement message 392 (described in [RFC4861]) with the M flag set to 1, the IPv6 393 CE router MUST do DHCPv6 address assignment (request an IA_NA 394 option). 396 WAA-7: If the IPv6 CE router does not acquire global IPv6 397 address(es) from either SLAAC or DHCPv6, then it MUST create 398 global IPv6 address(es) from its delegated prefix(es) and 399 configure those on one of its internal virtual network 400 interfaces, unless configured to require a global IPv6 401 address on the WAN interface. 403 WAA-8: The CE Router MUST support the DHCPv6 SOL_MAX_RT option 404 [I-D.droms-dhc-dhcpv6-maxsolrt-update] in a received DHCPv6 405 Advertise or Reply message and set its internal SOL_MAX_RT 406 parameter to the value contained in the SOL_MAX_RT option. 408 WAA-9: As a router, the IPv6 CE router MUST follow the weak host 409 (Weak ES) model [RFC1122]. When originating packets from an 410 interface, it will use a source address from another one of 411 its interfaces if the outgoing interface does not have an 412 address of suitable scope. 414 Prefix delegation requirements: 416 WPD-1: The IPv6 CE router MUST support DHCPv6 prefix delegation 417 requesting router behavior as specified in [RFC3633] (IA_PD 418 option). The IPv6 CE Router SHOULD support the 419 [I-D.ietf-dhc-pd-exclude] PD-Exclude option. 421 WPD-2: The IPv6 CE router MAY indicate as a hint to the delegating 422 router the size of the prefix it requires. If so, it MUST 423 ask for a prefix large enough to assign one /64 for each of 424 its interfaces, rounded up to the nearest nibble, and SHOULD 425 be configurable to ask for more. 427 WPD-3: The IPv6 CE router MUST be prepared to accept a delegated 428 prefix size different from what is given in the hint. If the 429 delegated prefix is too small to address all of its 430 interfaces, the IPv6 CE router SHOULD log a system management 431 error. 433 WPD-4: By default, the IPv6 CE router MUST initiate DHCPv6 prefix 434 delegation when either the M or O flags are set to 1 in a 435 received Router Advertisement message. 437 WPD-5: If the delegated prefix(es) are aggregate route(s) of 438 multiple, more-specific routes, the IPv6 CE router MUST 439 discard packets that match the aggregate route(s), but not 440 any of the more-specific routes. In other words, the next 441 hop for the aggregate route(s) should be the null 442 destination. This is necessary to prevent forwarding loops 443 when some addresses covered by the aggregate are not 444 reachable [RFC4632]. 446 (a) The IPv6 CE router SHOULD send an ICMPv6 Destination 447 Unreachable message in accordance with Section 3.1 of 448 [RFC4443] back to the source of the packet, if the 449 packet is to be dropped due to this rule. 451 WPD-6: If the IPv6 CE router requests both an IA_NA and an IA_PD 452 option in DHCPv6, it MUST accept an IA_PD option in DHCPv6 453 Advertise/Reply messages, even if the message does not 454 contain any addresses, unless configured to only obtain its 455 WAN IPv6 address via DHCPv6. 457 WPD-7: By default, an IPv6 CE router MUST NOT initiate any dynamic 458 routing protocol on its WAN interface. 460 4.3. LAN-Side Configuration 462 The IPv6 CE router distributes configuration information obtained 463 during WAN interface provisioning to IPv6 hosts and assists IPv6 464 hosts in obtaining IPv6 addresses. It also supports connectivity of 465 these devices in the absence of any working WAN interface. 467 An IPv6 CE router is expected to support an IPv6 end-user network and 468 IPv6 hosts that exhibit the following characteristics: 470 1. Link-local addresses may be insufficient for allowing IPv6 471 applications to communicate with each other in the end-user 472 network. The IPv6 CE router will need to enable this 473 communication by providing globally scoped unicast addresses or 474 ULA's [RFC4193], whether or not WAN connectivity exists. 476 2. IPv6 hosts should be capable of using SLAAC and may be capable of 477 using DHCPv6 for acquiring their addresses. 479 3. IPv6 hosts may use DHCPv6 for other configuration information, 480 such as the DNS_SERVERS option for acquiring DNS information. 482 Unless otherwise specified, the following requirements apply to the 483 IPv6 CE router's LAN interfaces only. 485 ULA requirements: 487 ULA-1: The IPv6 CE router SHOULD be capable of generating a ULA 488 prefix [RFC4193]. 490 ULA-2: An IPv6 CE router with a ULA prefix MUST maintain this prefix 491 consistently across reboots. 493 ULA-3: The value of the ULA prefix SHOULD be user-configurable. 495 ULA-4: By default, the IPv6 CE router MUST act as a site border 496 router according to Section 4.3 of [RFC4193] and filter 497 packets with local IPv6 source or destination addresses 498 accordingly. 500 ULA-5: An IPv6 CE router MUST NOT advertise itself as a default 501 router with a Router Lifetime greater than zero whenever all 502 of its configured and delegated prefixes are ULA prefixes. 504 LAN requirements: 506 L-1: The IPv6 CE router MUST support router behavior according to 507 Neighbor Discovery for IPv6 [RFC4861]. 509 L-2: The IPv6 CE router MUST assign a separate /64 from its 510 delegated prefix(es) (and ULA prefix if configured to provide 511 ULA addressing) for each of its LAN interfaces. 513 L-3: An IPv6 CE router MUST advertise itself as a router for the 514 delegated prefix(es) (and ULA prefix if configured to provide 515 ULA addressing) using the "Route Information Option" specified 516 in Section 2.3 of [RFC4191]. This advertisement is 517 independent of having or not having IPv6 connectivity on the 518 WAN interface. 520 L-4: An IPv6 CE router MUST NOT advertise itself as a default 521 router with a Router Lifetime [RFC4861] greater than zero if 522 it has no prefixes configured or delegated to it. 524 L-5: The IPv6 CE router MUST make each LAN interface an advertising 525 interface according to [RFC4861]. 527 L-6: In Router Advertisement messages, the Prefix Information 528 option's A and L flags MUST be set to 1 by default. 530 L-7: The A and L flags' settings SHOULD be user-configurable. 532 L-8: The IPv6 CE router MUST support a DHCPv6 server capable of 533 IPv6 address assignment according to [RFC3315] OR a stateless 534 DHCPv6 server according to [RFC3736] on its LAN interfaces. 536 L-9: Unless the IPv6 CE router is configured to support the DHCPv6 537 IA_NA option, it SHOULD set the M flag to 0 and the O flag to 538 1 in its Router Advertisement messages [RFC4861]. 540 L-10: The IPv6 CE router MUST support providing DNS information in 541 the DHCPv6 DNS_SERVERS and DOMAIN_LIST options [RFC3646]. 543 L-11: The IPv6 CE router MUST support providing DNS information in 544 the Router Advertisement Recursive DNS Server (RDNSS) and 545 DNSSL options. 547 L-12: The IPv6 CE router SHOULD make available a subset of DHCPv6 548 options (as listed in Section 5.3 of [RFC3736]) received from 549 the DHCPv6 client on its WAN interface to its LAN-side DHCPv6 550 server. 552 L-13: If the delegated prefix changes, i.e., the current prefix is 553 replaced with a new prefix without any overlapping time 554 period, then the IPv6 CE router MUST immediately advertise the 555 old prefix with a Preferred Lifetime of zero and a Valid 556 Lifetime of either a) zero, or b) the lower of the current 557 Valid Lifetime and two hours (which must be decremented in 558 real time) in a Router Advertisement message as described in 559 Section 5.5.3, (e) of [RFC4862]. 561 L-14: The IPv6 CE router MUST send an ICMPv6 Destination Unreachable 562 message, code 5 (Source address failed ingress/egress policy) 563 for packets forwarded to it that use an address from a prefix 564 that has been deprecated. 566 4.4. Transition Technologies Support 568 4.4.1. 6rd 570 6rd [RFC5969] specifies an automatic tunneling mechanism tailored to 571 advance deployment of IPv6 to end users via a service provider's IPv4 572 network infrastructure. Key aspects include automatic IPv6 prefix 573 delegation to sites, stateless operation, simple provisioning, and 574 service that is equivalent to native IPv6 at the sites that are 575 served by the mechanism. It is expected that such traffic is 576 forwarded over the CE Router's native IPv4 WAN interface, and not 577 encapsulated in another tunnel. 579 The CE Router SHOULD support 6rd functionality. If 6rd is supported, 580 it MUST be implemented according to [RFC5969]. The following CE 581 Requirements also apply: 583 . 585 6rd requirements: 587 6RD-1: The IPv6 CE router MUST support 6rd configuration via the 6rd 588 DHCPv4 Option (212). If the CE router has obtained an IPv4 589 network address through some other means such PPP, it SHOULD 590 use the DHCPINFORM request message [RFC2131] to request the 591 6rd DHCPv4 Option. The IPv6 CE router MAY use other 592 mechanisms to configure 6rd parameters. Such mechanisms are 593 outside the scope of this document. 595 6RD-2: If the IPv6 CE router is capable of automated configuration 596 of IPv4 through IPCP (i.e., over a PPP connection), it MUST 597 support user-entered configuration of 6rd. 599 6RD-3: If the CE router supports configuration mechanisms other than 600 the 6rd DHCPv4 Option 212 (user-entered, TR-69, etc.), the CE 601 router MUST support 6rd in "hub and spoke" mode. 6rd in "hub 602 and spoke" requires all IPv6 traffic to go to the 6rd Border 603 Relay. In effect, this requirement removes the "direct 604 connect to 6rd" route defined in Section 7.1.1 of [RFC5969]. 606 4.4.2. Dual-Stack Lite (DS-Lite) 608 Dual-Stack Lite [RFC6333] enables both continued support for IPv4 609 services and incentives for the deployment of IPv6. It also de- 610 couples IPv6 deployment in the Service Provider network from the rest 611 of the Internet, making incremental deployment easier. Dual-Stack 612 Lite enables a broadband service provider to share IPv4 addresses 613 among customers by combining two well-known technologies: IP in IP 614 (IPv4-in-IPv6) and Network Address Translation (NAT). It is expected 615 that DS-Lite traffic is forwarded over the CE Router's native IPv6 616 WAN interface, and not encapsulated in another tunnel. 618 The IPv6 CE Router SHOULD implement DS-Lite functionality. If DS- 619 Lite is supported, it MUST be implemented according to [RFC6333]. 620 The following CE Router requirements also apply: 622 WAN requirements: 624 DLW-1: The CE Router MUST support DS-Lite via the DS-Lite DHCPv6 625 option [RFC6334]. The IPv6 CE Router MAY use other 626 mechanisms to configure DS-Lite parameters. Such mechanisms 627 are outside the scope of this document. 629 DLW-2: IPv6 CE Router MUST NOT perform IPv4 Network Address 630 Translation (NAT) on IPv4 traffic encapsulated using DS-Lite. 632 DLW-3: If the IPv6 CE Router is configured with an IPv4 address on 633 its WAN interface then the IPv6 CE Router SHOULD disable the 634 DS-Lite B4 element. 636 4.5. Security Considerations 638 It is considered a best practice to filter obviously malicious 639 traffic (e.g., spoofed packets, "Martian" addresses, etc.). Thus, 640 the IPv6 CE router ought to support basic stateless egress and 641 ingress filters. The CE router is also expected to offer mechanisms 642 to filter traffic entering the customer network; however, the method 643 by which vendors implement configurable packet filtering is beyond 644 the scope of this document. 646 Security requirements: 648 S-1: The IPv6 CE router SHOULD support [RFC6092]. In particular, 649 the IPv6 CE router SHOULD support functionality sufficient for 650 implementing the set of recommendations in [RFC6092], 651 Section 4. This document takes no position on whether such 652 functionality is enabled by default or mechanisms by which 653 users would configure it. 655 S-2: The IPv6 CE router SHOULD support ingress filtering in 656 accordance with BCP 38 [RFC2827]. 658 S-3: If the IPv6 CE router firewall is configured to filter incoming 659 tunneled data, the firewall SHOULD provide the capability to 660 filter decapsulated packets from a tunnel. 662 5. IANA Considerations 664 This document has no actions for IANA. 666 6. Acknowledgements 668 Thanks to the following people (in alphabetical order) for their 669 guidance and feedback: 671 Mikael Abrahamsson, Tore Anderson, Merete Asak, Scott Beuker, Mohamed 672 Boucadair, Rex Bullinger, Brian Carpenter, Tassos Chatzithomaoglou, 673 Lorenzo Colitti, Remi Denis-Courmont, Gert Doering, Alain Durand, 674 Katsunori Fukuoka, Tony Hain, Thomas Herbst, Kevin Johns, Erik Kline, 675 Stephen Kramer, Victor Kuarsingh, Francois-Xavier Le Bail, Arifumi 676 Matsumoto, David Miles, Shin Miyakawa, Jean-Francois Mule, Michael 677 Newbery, Carlos Pignataro, John Pomeroy, Antonio Querubin, Hiroki 678 Sato, Teemu Savolainen, Matt Schmitt, David Thaler, Mark Townsley, 679 Bernie Volz, Dan Wing, James Woodyatt, Carl Wuyts, and Cor Zwart. 681 This document is based in part on CableLabs' eRouter specification. 682 The authors wish to acknowledge the additional contributors from the 683 eRouter team: 685 Ben Bekele, Amol Bhagwat, Ralph Brown, Eduardo Cardona, Margo Dolas, 686 Toerless Eckert, Doc Evans, Roger Fish, Michelle Kuska, Diego 687 Mazzola, John McQueen, Harsh Parandekar, Michael Patrick, Saifur 688 Rahman, Lakshmi Raman, Ryan Ross, Ron da Silva, Madhu Sudan, Dan 689 Torbet, and Greg White. 691 7. Contributors 693 The following people have participated as co-authors or provided 694 substantial contributions to this document: Ralph Droms, Kirk 695 Erichsen, Fred Baker, Jason Weil, Lee Howard, Jean-Francois Tremblay, 696 Yiu Lee, John Jason Brzozowski, and Heather Kirksey. 698 8. References 700 8.1. Normative References 702 [I-D.droms-dhc-dhcpv6-maxsolrt-update] 703 Droms, R., "Modification to Default Value of MAX_SOL_RT", 704 draft-droms-dhc-dhcpv6-maxsolrt-update-00 (work in 705 progress), November 2011. 707 [I-D.ietf-dhc-pd-exclude] 708 Korhonen, J., Savolainen, T., Krishnan, S., and O. Troan, 709 "Prefix Exclude Option for DHCPv6-based Prefix 710 Delegation", draft-ietf-dhc-pd-exclude-04 (work in 711 progress), December 2011. 713 [I-D.ietf-pcp-base] 714 Cheshire, S., Boucadair, M., Selkirk, P., Wing, D., and R. 715 Penno, "Port Control Protocol (PCP)", 716 draft-ietf-pcp-base-23 (work in progress), February 2012. 718 [RFC1122] Braden, R., "Requirements for Internet Hosts - 719 Communication Layers", STD 3, RFC 1122, October 1989. 721 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 722 Requirement Levels", BCP 14, RFC 2119, March 1997. 724 [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", 725 RFC 2131, March 1997. 727 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 728 Networks", RFC 2464, December 1998. 730 [RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering: 731 Defeating Denial of Service Attacks which employ IP Source 732 Address Spoofing", BCP 38, RFC 2827, May 2000. 734 [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., 735 and M. Carney, "Dynamic Host Configuration Protocol for 736 IPv6 (DHCPv6)", RFC 3315, July 2003. 738 [RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic 739 Host Configuration Protocol (DHCP) version 6", RFC 3633, 740 December 2003. 742 [RFC3646] Droms, R., "DNS Configuration options for Dynamic Host 743 Configuration Protocol for IPv6 (DHCPv6)", RFC 3646, 744 December 2003. 746 [RFC3736] Droms, R., "Stateless Dynamic Host Configuration Protocol 747 (DHCP) Service for IPv6", RFC 3736, April 2004. 749 [RFC4075] Kalusivalingam, V., "Simple Network Time Protocol (SNTP) 750 Configuration Option for DHCPv6", RFC 4075, May 2005. 752 [RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and 753 More-Specific Routes", RFC 4191, November 2005. 755 [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast 756 Addresses", RFC 4193, October 2005. 758 [RFC4242] Venaas, S., Chown, T., and B. Volz, "Information Refresh 759 Time Option for Dynamic Host Configuration Protocol for 760 IPv6 (DHCPv6)", RFC 4242, November 2005. 762 [RFC4443] Conta, A., Deering, S., and M. Gupta, "Internet Control 763 Message Protocol (ICMPv6) for the Internet Protocol 764 Version 6 (IPv6) Specification", RFC 4443, March 2006. 766 [RFC4605] Fenner, B., He, H., Haberman, B., and H. Sandick, 767 "Internet Group Management Protocol (IGMP) / Multicast 768 Listener Discovery (MLD)-Based Multicast Forwarding 769 ("IGMP/MLD Proxying")", RFC 4605, August 2006. 771 [RFC4632] Fuller, V. and T. Li, "Classless Inter-domain Routing 772 (CIDR): The Internet Address Assignment and Aggregation 773 Plan", BCP 122, RFC 4632, August 2006. 775 [RFC4779] Asadullah, S., Ahmed, A., Popoviciu, C., Savola, P., and 776 J. Palet, "ISP IPv6 Deployment Scenarios in Broadband 777 Access Networks", RFC 4779, January 2007. 779 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 780 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 781 September 2007. 783 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 784 Address Autoconfiguration", RFC 4862, September 2007. 786 [RFC4864] Van de Velde, G., Hain, T., Droms, R., Carpenter, B., and 787 E. Klein, "Local Network Protection for IPv6", RFC 4864, 788 May 2007. 790 [RFC5072] S.Varada, Haskins, D., and E. Allen, "IP Version 6 over 791 PPP", RFC 5072, September 2007. 793 [RFC5942] Singh, H., Beebee, W., and E. Nordmark, "IPv6 Subnet 794 Model: The Relationship between Links and Subnet 795 Prefixes", RFC 5942, July 2010. 797 [RFC5969] Townsley, W. and O. Troan, "IPv6 Rapid Deployment on IPv4 798 Infrastructures (6rd) -- Protocol Specification", 799 RFC 5969, August 2010. 801 [RFC6092] Woodyatt, J., "Recommended Simple Security Capabilities in 802 Customer Premises Equipment (CPE) for Providing 803 Residential IPv6 Internet Service", RFC 6092, 804 January 2011. 806 [RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual- 807 Stack Lite Broadband Deployments Following IPv4 808 Exhaustion", RFC 6333, August 2011. 810 [RFC6334] Hankins, D. and T. Mrugalski, "Dynamic Host Configuration 811 Protocol for IPv6 (DHCPv6) Option for Dual-Stack Lite", 812 RFC 6334, August 2011. 814 [RFC6434] Jankiewicz, E., Loughney, J., and T. Narten, "IPv6 Node 815 Requirements", RFC 6434, December 2011. 817 8.2. Informative References 819 [MULTIHOMING-WITHOUT-NAT] 820 Troan, O., Ed., Miles, D., Matsushima, S., Okimoto, T., 821 and D. Wing, "IPv6 Multihoming without Network Address 822 Translation", Work in Progress, December 2010. 824 [RFC6144] Baker, F., Li, X., Bao, C., and K. Yin, "Framework for 825 IPv4/IPv6 Translation", RFC 6144, March 2011. 827 [UPnP-IGD] 828 UPnP Forum, "Universal Plug and Play (UPnP) Internet 829 Gateway Device (IGD)", November 2001, 830 . 832 Appendix A. Changes from RFC 6204 834 1. Added IP transition technologies available in RFC form. 836 2. Changed bullet G-5 to augment the condition of losing IPv6 837 default router(s) with loss of connectivity. 839 3. Removed bullet WAA-7 due to not reaching consensus by various 840 service provider standards bodies. The removal of text does not 841 remove any critical functionality from the CE specification. 843 4. Changed bullet WAA-8 to qualify WAN behavior only if not 844 configured to perform DHCPv6. This way a deployment specific 845 profile can mandate DHCPv6 numbered WAN without conflicting with 846 this document. 848 5. Changed the WPD-2 bullet from MUST be configurable to SHOULD be 849 configurable. 851 6. Changed bullet WPD-4 for a default behavior without compromising 852 any prior specification of the CE device. The change was needed 853 by a specific layer 1 deployment which wanted to specify a MUST 854 for DHCPv6 in their layer 1 profile and not conflict with this 855 document. 857 7. Changed bullet WPD-7 to qualify text for DHCPv6. Removed W-5 858 and WPD-5 because the text does not have consensus from the IETF 859 DHC Working Group for what the final solution related to the 860 removed bullets will be. 862 8. Added a new WAN DHCPv6 requirement for SOL_MAX_RT of DHCPv6 so 863 that if an service provider does not have DHCPv6 service enabled 864 CE routers do not send too frequent DHCPv6 requests to the 865 service provider DHCPv6 server. 867 9. Changed bullet L-11 from SHOULD provide DNS options in the RA to 868 MUST provide DNS option in the RA. 870 10. New bullet added to the Security Considerations section due to 871 addition of transition technology. The CE router filters 872 decapsulated 6rd data. 874 11. Minor change involved changing ICMP to ICMPv6. 876 12. Added PCP client requirement for the WAN. 878 13. Added a requirement for the DHCPv6 pd-exclude option. 880 Authors' Addresses 882 Hemant Singh 883 Cisco Systems, Inc. 884 1414 Massachusetts Ave. 885 Boxborough, MA 01719 886 USA 888 Phone: +1 978 936 1622 889 EMail: shemant@cisco.com 890 URI: http://www.cisco.com/ 892 Wes Beebee 893 Cisco Systems, Inc. 894 1414 Massachusetts Ave. 895 Boxborough, MA 01719 896 USA 898 Phone: +1 978 936 2030 899 EMail: wbeebee@cisco.com 900 URI: http://www.cisco.com/ 902 Chris Donley 903 CableLabs 904 858 Coal Creek Circle 905 Louisville, CO 80027 906 USA 908 EMail: c.donley@cablelabs.com 910 Barbara Stark 911 AT&T 912 725 W Peachtree St. 913 Atlanta, GA 30308 914 USA 916 EMail: barbara.stark@att.com 917 Ole Troan (editor) 918 Cisco Systems, Inc. 919 Telemarksvingen 20 920 N-0655 OSLO, 921 Norway 923 EMail: ot@cisco.com