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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 v6ops V. Kuarsingh, Ed. 3 Internet-Draft Rogers Communications 4 Intended status: Informational L. Howard 5 Expires: January 12, 2013 Time Warner Cable 6 July 11, 2012 8 Wireline Incremental IPv6 9 draft-ietf-v6ops-wireline-incremental-ipv6-05 11 Abstract 13 Operators worldwide are in various stages of preparing for, or 14 deploying IPv6 into their networks. The operators often face 15 difficult challenges related to both IPv6 introduction along with 16 those related to IPv4 run out. Operators will need to meet the 17 simultaneous needs of IPv6 connectivity and continue support for IPv4 18 connectivity for legacy devices with a stagnant supply of IPv4 19 addresses. The IPv6 transition will take most networks from an IPv4- 20 only environment to an IPv6 dominant environment with long transition 21 period varying by operator. This document helps provide a framework 22 for wireline providers who are faced with the challenges of 23 introducing IPv6 along with meeting the legacy needs of IPv4 24 connectivity utilizing well defined and commercially available IPv6 25 transition technologies. 27 Status of this Memo 29 This Internet-Draft is submitted in full conformance with the 30 provisions of BCP 78 and BCP 79. 32 Internet-Drafts are working documents of the Internet Engineering 33 Task Force (IETF). Note that other groups may also distribute 34 working documents as Internet-Drafts. The list of current Internet- 35 Drafts is at http://datatracker.ietf.org/drafts/current/. 37 Internet-Drafts are draft documents valid for a maximum of six months 38 and may be updated, replaced, or obsoleted by other documents at any 39 time. It is inappropriate to use Internet-Drafts as reference 40 material or to cite them other than as "work in progress." 42 This Internet-Draft will expire on January 12, 2013. 44 Copyright Notice 46 Copyright (c) 2012 IETF Trust and the persons identified as the 47 document authors. All rights reserved. 49 This document is subject to BCP 78 and the IETF Trust's Legal 50 Provisions Relating to IETF Documents 51 (http://trustee.ietf.org/license-info) in effect on the date of 52 publication of this document. Please review these documents 53 carefully, as they describe your rights and restrictions with respect 54 to this document. Code Components extracted from this document must 55 include Simplified BSD License text as described in Section 4.e of 56 the Trust Legal Provisions and are provided without warranty as 57 described in the Simplified BSD License. 59 Table of Contents 61 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 62 2. Operator Assumptions . . . . . . . . . . . . . . . . . . . . . 4 63 3. Reasons and Considerations for a Phased Approach . . . . . . . 5 64 3.1. Relevance of IPv6 and IPv4 . . . . . . . . . . . . . . . . 6 65 3.2. IPv4 Resource Challenges . . . . . . . . . . . . . . . . . 6 66 3.3. IPv6 Introduction and Operational Maturity . . . . . . . . 7 67 3.4. Service Management . . . . . . . . . . . . . . . . . . . . 8 68 3.5. Sub-Optimal Operation of Transition Technologies . . . . . 8 69 3.6. Future IPv6 Network . . . . . . . . . . . . . . . . . . . 9 70 4. IPv6 Transition Technology Analysis . . . . . . . . . . . . . 9 71 4.1. Automatic Tunneling using 6to4 and Teredo . . . . . . . . 9 72 4.2. Carrier Grade NAT (NAT444) . . . . . . . . . . . . . . . . 10 73 4.3. 6RD . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 74 4.4. Native Dual Stack . . . . . . . . . . . . . . . . . . . . 11 75 4.5. DS-Lite . . . . . . . . . . . . . . . . . . . . . . . . . 11 76 4.6. NAT64 . . . . . . . . . . . . . . . . . . . . . . . . . . 12 77 5. IPv6 Transition Phases . . . . . . . . . . . . . . . . . . . . 12 78 5.1. Phase 0 - Foundation . . . . . . . . . . . . . . . . . . . 13 79 5.1.1. Phase 0 - Foundation: Training . . . . . . . . . . . . 13 80 5.1.2. Phase 0 - Foundation: Routing . . . . . . . . . . . . 13 81 5.1.3. Phase 0 - Foundation: Network Policy and Security . . 14 82 5.1.4. Phase 0 - Foundation: Transition Architecture . . . . 14 83 5.1.5. Phase 0- Foundation: Tools and Management . . . . . . 15 84 5.2. Phase 1 - Tunneled IPv6 . . . . . . . . . . . . . . . . . 15 85 5.2.1. 6RD Deployment Considerations . . . . . . . . . . . . 16 86 5.3. Phase 2: Native Dual Stack . . . . . . . . . . . . . . . . 18 87 5.3.1. Native Dual Stack Deployment Considerations . . . . . 19 88 5.4. Intermediate Phase for CGN . . . . . . . . . . . . . . . . 19 89 5.4.1. CGN Deployment Considerations . . . . . . . . . . . . 21 90 5.5. Phase 3 - IPv6-Only . . . . . . . . . . . . . . . . . . . 22 91 5.5.1. DS-Lite Deployment Considerations . . . . . . . . . . 23 92 5.5.2. NAT64 Deployment Considerations . . . . . . . . . . . 24 93 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25 94 7. Security Considerations . . . . . . . . . . . . . . . . . . . 25 95 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 25 96 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 25 97 9.1. Normative References . . . . . . . . . . . . . . . . . . . 25 98 9.2. Informative References . . . . . . . . . . . . . . . . . . 25 99 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 28 101 1. Introduction 103 This draft sets out to help wireline operators in planning their IPv6 104 deployments while ensuring continued support for IPv6-incapable 105 consumer devices and applications. This document identifies which 106 technologies can be used incrementally to transition from IPv4-only 107 to an IPv6 dominant environment with support for dual stack 108 operation. The end state goal for most operators will be IPv6-only, 109 but the path to this final state will heavily depend on the amount of 110 legacy equipment resident in end networks and management of long tail 111 IPv4-only content. Although no single plan will work for all 112 operators, options listed herein provide a baseline which can be 113 included in many plans. 115 This draft is intended for wireline environments which include Cable, 116 DSL and/or fiber as the access method to the end consumer. This 117 document attempts to follow the principles laid out in [RFC6180] 118 which provides guidance on using IPv6 transition mechanisms. This 119 document will focus on technologies which enable and mature IPv6 120 within the operator's network, but will also include a cursory view 121 of IPv4 connectivity continuance. The focal transition technologies 122 include 6RD [RFC5969], DS-Lite [RFC6333], NAT64 [RFC6146] and Dual 123 Stack operation which may also include a CGN/NAT444 deployment. 124 Focus on these technologies is based on their inclusion in many off- 125 the-shelf CPEs and availability in commercially available equipment. 127 2. Operator Assumptions 129 For the purposes of this document, the authors assume: 131 - The operator is considering deploying IPv6 or is in progress in 132 deploying IPv6 134 - The operator has a legacy IPv4 subscriber base that will 135 continue to exist for a period of time 137 - The operator will want to minimize the level of disruption to 138 the existing and new subscribers by minimizing the number of 139 technologies and functions that are needed to mediate any given 140 set of subscribers flows (overall preference for Native IP flows) 142 - The operator is able to run Dual Stack on their own core network 143 and is able to transition their own services to support IPv6 145 Based on these assumptions, an operator will want to utilize 146 technologies that minimize the need to tunnel, translate or mediate 147 flows to help optimize traffic flow and lower the cost impacts of 148 transition technologies. Transition technology selections should be 149 made to mediate the non-dominant IP family flows and allow native 150 routing (IPv4 and/or IPv6) to forward the dominant traffic whenever 151 possible. This allows the operator to minimize the cost of IPv6 152 transition technologies by minimizing the transition technology 153 deployment size. 155 An operator may also choose to prefer more IPv6 focused models where 156 the use of transition technologies are based on an effort to enable 157 IPv6 at the base layer as soon as possible. Some operators may want 158 to promote IPv6 early on in the deployment and have IPv6 traffic 159 perform optimally from the outset. This desire would need to be 160 weighed against the cost and support impacts of such a choice and the 161 quality of experience offered to subscribers. 163 3. Reasons and Considerations for a Phased Approach 165 When faced with the challenges described in the introduction, 166 operators may need to consider a phased approach when adding IPv6 to 167 an existing subscriber base. A phased approach allows the operator 168 to add in IPv6 while not ignoring legacy IPv4 connection 169 requirements. Some of the main challenges the operator will face 170 include: 172 - IPv4 exhaustion may occur long before all traffic is able to be 173 delivered over IPv6, necessitating IPv4 address sharing 175 - IPv6 will pose operational challenges since some of the software 176 is quite new and has had short run time in large production 177 environments and organizations are also not acclimatized to 178 supporting IPv6 as a service 180 - Connectivity modes will move from IPv4-only to Dual Stack in the 181 home, changing functional behaviors in the consumer network and 182 increasing support requirements for the operator 184 - Although IPv6 support on CPEs is a newer phenomenon, there is a 185 strong push by operators and the industry as a whole to enable 186 IPv6 on devices. As demand grows, IPv6 enablement will no longer 187 be optional, but necessary on CPEs. Documents like [RFC6540] 188 provide useful tools in the short term to help vendors and 189 implementors understand what "IPv6 support" means. 191 These challenges will occur over a period of time, which means that 192 the operator's plans need to address the ever changing requirements 193 of the network and subscriber demand. Although phases will be 194 presented in this document, not all operators may need to enable each 195 discrete phase. It is possible that characteristics in individual 196 networks may allow certain operators to skip or jump to various 197 phases. 199 3.1. Relevance of IPv6 and IPv4 201 The delivery of high-quality unencumbered Internet service should be 202 the primary goal for operators. With the imminent exhaustion of 203 IPv4, IPv6 will offer the highest quality of experience in the long 204 term. Even though the operator may be focused on IPv6 delivery, they 205 should be aware that both IPv4 and IPv6 will play a role in the 206 Internet experience during transition. The Internet is made of many 207 interconnecting systems, networks, hardware, software and content 208 sources - all of which will move to IPv6 at different rates. 210 Many subscribers use older operating systems and hardware which 211 support IPv4-only operation. Internet subscribers don't buy IPv4 or 212 IPv6 connections; they buy Internet connections, which demands the 213 need to support both IPv4 and IPv6 for as long at the subscriber's 214 home network demands such support. The operator may be able to 215 leverage one or the other protocol to help bridge connectivity on the 216 operator's network, but the home network will likely demand both IPv4 217 and IPv6 for some time. 219 3.2. IPv4 Resource Challenges 221 Since connectivity to IPv4-only endpoints and/or content will remain 222 common, IPv4 resource challenges are of key concern to operators. 223 The lack of new IPv4 addresses for additional devices means that 224 meeting the growth in demand of IPv4 connections in some networks 225 will require address sharing. 227 Networks are growing at different rates including those in emerging 228 markets and established networks based on the proliferation of 229 Internet based services and devices. IPv4 address constraints will 230 likely affect many if not most operators at some point, increasing 231 the benefits of IPv6. IPv4 address exhaustion is a consideration 232 when selecting technologies which rely on IPv4 to supply IPv6 233 services, such as 6RD. Additionally, if native Dual Stack is 234 considered by the operator, challenges related to IPv4 address 235 exhaustion remain a concern. 237 Some operators may be able to reclaim small amounts IPv4 addresses 238 through addressing efficiencies in the network, although this will 239 have little lasting benefits to the network and not meet longer term 240 connectivity needs. The lack of new global IPv4 address allocations 241 will therefore force operators to support some form of IPv4 address 242 sharing and may impact technological options for transition once the 243 operator runs out of new IPv4 addresses for assignment. 245 3.3. IPv6 Introduction and Operational Maturity 247 The introduction of IPv6 will require new operational practices. The 248 IPv4 environment we have today was built over many years and matured 249 by experience. Although many of these experiences are transferable 250 from IPv4 to IPv6, new experience and practices specific to IPv6 will 251 be needed. 253 Engineering and Operational staff will need to develop experience 254 with IPv6. Inexperience may lead to early IPv6 deployment 255 instability, and operators should consider this when selecting 256 technologies for initial transition. Operators may not want to 257 subject their mature IPv4 service to a "new IPv6" path initially 258 while it may be going through growing pains. DS-Lite [RFC6333] and 259 NAT64 [RFC6146] are both technologies which requires IPv6 to support 260 connectivity to IPv4 endpoints or content over an IPv6-only access 261 network. 263 Further, some of these transition technologies are new and require 264 refinement within running code. Deployment experience is required to 265 expose bugs and stabilize software in production environments. Many 266 supporting systems are also under development and have newly 267 developed IPv6 functionality including vendor implementations of 268 DHCPv6, management tools, monitoring systems, diagnostic systems, 269 logging, along with other elements. 271 Although the base technological capabilities exist to enable and run 272 IPv6 in most environments, organizational experience is low. Until 273 such time as each key technical member of an operator's organization 274 can identify IPv6, understand its relevance to the IP service 275 offering, how it operates and how to troubleshoot it, the deployment 276 needs to mature, and may be subject to subscriber-impacting events. 277 This fact should not incline operators to delay their IPv6 278 deployment, but should drive them to deploy IPv6 sooner to gain the 279 much needed experience before IPv6 is the only viable way to connect 280 new hosts to the network. 282 It should also be noted that although many transition technologies 283 may be new, and some code related to access environments may be new, 284 there is a large segment of the networking fabric which has had IPv6 285 available for a long period of time and has had extended exposure in 286 production. Operators may use this to their advantage by first 287 enabling IPv6 in the core of their network then work outward towards 288 the subscriber edge. 290 3.4. Service Management 292 Services are managed within most networks and are often based on the 293 gleaning and monitoring of IPv4 addresses assigned to endpoints. 294 Operators will need to address such management tools, troubleshooting 295 methods and storage facilities (such as databases) to deal with not 296 just a new address type containing a 128-bit IPv6 address [RFC2460], 297 but often both IPv4 and IPv6 at the same time. Examination of 298 address type, and recording delegated prefixes along with single 299 address assignments, will likely require additional development. 301 With any Dual Stack service - whether Native, 6RD-based, DS-Lite, 302 NAT64 or otherwise - two address families may need to be managed 303 simultaneously to help provide for the full Internet experience. 304 This would indicate that IPv6 management is not just a simple add in, 305 but needs to be well integrated into the service management 306 infrastructure. In the early transition phases, it's quite likely 307 that many systems will be missed and that IPv6 services will go un- 308 monitored and impairments undetected. 310 These issues may be of consideration when selecting technologies that 311 require IPv6 as the base protocol to delivery IPv4 connectivity. 312 Instability on the IPv6 service in such a case would impact IPv4 313 services. 315 3.5. Sub-Optimal Operation of Transition Technologies 317 Native delivery of IPv4 and IPv6 provides a solid foundation for 318 delivery of Internet services to subscribers since native IP paths 319 are well understood and networks are often optimized to send such 320 traffic efficiently. Transition technologies however, may alter the 321 normal path of traffic or reduce the path MTU, removing many network 322 efficiencies built for native IP flows. Tunneling and translation 323 devices may not be located on the most optimal path in line with the 324 natural traffic flow (based on route computation) and therefore may 325 increase latency. These paths may also add additional points of 326 failure. 328 Generally, the operator will want to deliver native IPv6 as soon as 329 possible and utilize transition technologies only when required. 330 Transition technologies may be used to provide continued access to 331 IPv4 via tunneling and/or translation or may be used to deliver IPv6 332 connectivity. The delivery of Internet or internal services should 333 be considered by the operator, since supplying connections using a 334 transition technology will reduce the overall performance for the 335 subscriber. 337 When choosing between various transition technologies, operators 338 should consider the benefits and drawbacks of each option. Some 339 technologies like CGN/NAT444 utilize many existing addressing and 340 management practices. Other options such as DS-Lite and NAT64 remove 341 the IPv4 addressing requirement to the subscriber premise device but 342 require IPv6 to be operational and well supported. 344 3.6. Future IPv6 Network 346 An operator should also be aware that longer-term plans may include 347 IPv6-only operation in all or much of the network. The IPv6-only 348 operation may be complemented by technologies such as NAT64 for long- 349 tail IPv4 content reach. This longer term view may be distant to 350 some, but should be considered when planning out networks, addressing 351 and services. The needs and costs of maintaining two IP stacks will 352 eventually become burdensome and simplification will be desirable. 353 The operators should plan for this state and not make IPv6 inherently 354 dependent on IPv4 as this would unnecessarily constrain the network. 356 4. IPv6 Transition Technology Analysis 358 Operators should understand the main transition technologies for IPv6 359 deployment and IPv4 run out. This draft provides a brief description 360 of some of the mainstream and commercially available options. This 361 analysis is focused on the applicability of technologies to deliver 362 residential services and less focused on commercial access, wireless, 363 or infrastructure support. 365 The technologies in focus for this document are targeted on those 366 commercially available and in deployment. 368 4.1. Automatic Tunneling using 6to4 and Teredo 370 Even when operators may not be actively deploying IPv6, automatic 371 mechanisms exist on subscriber operating systems and CPE hardware. 372 Such technologies include 6to4 [RFC3056], which is most commonly used 373 with anycast relays [RFC3068]. Teredo [RFC4380] is also used widely 374 by many Internet hosts. 376 Documents such as [RFC6343] have been written to help operators 377 understand observed problems with 6to4 deployments and provides 378 guidelines on how to improve it's performance. An operator may want 379 to provide local relays for 6to4 and/or Teredo to help improve the 380 protocol's performance for ambient traffic utilizing these IPv6 381 connectivity methods. Experiences such as those described in 382 [I-D.jjmb-v6ops-comcast-ipv6-experiences] show that local relays have 383 proved beneficial to 6to4 protocol performance. 385 Operators should also be aware of breakage cases for 6to4 if non- 386 RFC1918 addresses are used within CGN/NAT444 zones. Many off-the- 387 shelf CPEs and operating systems may turn on 6to4 without a valid 388 return path to the originating (local) host. This particular use 389 case can occur if any space other than [RFC1918] is used, including 390 Shared Address Space [RFC6598] or space registered to another 391 organization (squat space). The operator can use 6to4-PMT 392 [I-D.kuarsingh-v6ops-6to4-provider-managed-tunnel] or attempt to 393 block 6to4 operation entirely by blocking the anycast ranges 394 associated with [RFC3068]. 396 4.2. Carrier Grade NAT (NAT444) 398 Carrier Grade NAT (CGN), specifically as deployed in a NAT444 399 scenario [I-D.ietf-behave-lsn-requirements], may prove beneficial for 400 those operators who offer Dual Stack services to subscriber endpoints 401 once they exhaust their pools of IPv4 addresses. CGNs, and address 402 sharing overall, are known to cause certain challenges for the IPv4 403 service [RFC6269][I-D.donley-nat444-impacts], but may be necessary 404 depending on how an operator has chosen to deal with IPv6 transition 405 and legacy IPv4 connectivity requirements. 407 In a network where IPv4 address availability is low, CGN/NAT444, may 408 provide continued access to IPv4 endpoints. Some of the advantages 409 of using CGN/NAT444 include the similarities in provisioning and 410 activation models. IPv4 hosts in a CGN/NAT444 deployment will likely 411 inherent the same addressing and management procedures as legacy 412 IPv4, globally addressed hosts (i.e. DHCPv6, DNSv4, TFTP, TR-069 413 etc). 415 4.3. 6RD 417 6RD [RFC5969] provides a way of offering IPv6 connectivity to 418 subscriber endpoints when native IPv6 addressing on the access 419 network is not yet possible. 6RD provides tunneled connectivity for 420 IPv6 over the existing IPv4 path. As the access edge is upgraded and 421 subscriber premise equipment is replaced, 6RD can be replace by 422 native IPv6 connectivity. 6RD can be delivered over top a CGN/NAT444 423 deployment, but this would cause all traffic to be subject to some 424 type of transition technology. 426 6RD may also be advantageous during the early transition while IPv6 427 traffic volumes are low. During this period, the operator can gain 428 experience with IPv6 on the core and improve their peering framework 429 to match those of the IPv4 service. 6RD scales by adding relays to 430 the operator's network. Another advantage for 6RD is that the 431 operator does not need a DHCPv6 address assignment infrastructure and 432 does not need to support IPv6 routing to the CPE to support a 433 delegated prefix (as it's derived from the IPv4 address and other 434 configuration parameters). 436 Client support is required for 6RD operation and may not be available 437 on deployed hardware. 6RD deployments may require the subscriber or 438 operator to replace the CPE. 6RD will also require parameter 439 configuration which can be powered by the operator through DHCPv4, 440 manually provisioned on the CPE or automatically through some other 441 means. Manual provisioning would likely limit deployment scale. 443 4.4. Native Dual Stack 445 Native Dual Stack is often referred to as the "gold standard" of IPv6 446 and IPv4 delivery. It is a method of service delivery that is 447 already used in many existing IPv6 deployments. Native Dual Stack 448 does, however, require that Native IPv6 be delivered through the 449 access network to the subscriber premise. This technology option is 450 desirable in many cases and can be used immediately if the access 451 network and subscriber premise equipment supports native IPv6. 453 An operator who runs out of IPv4 addresses to assign to subscribers 454 will not be able to provide traditional native Dual Stack 455 connectivity for new subscribers. In Dual Stack deployments where 456 sufficient IPv4 addresses are not available, CGN/NAT444 can be used 457 on the IPv4 path. 459 Delivering native Dual Stack would require the operator's core and 460 access network to support IPv6. Other systems like DHCP, DNS, and 461 diagnostic/management facilities need to be upgraded to support IPv6 462 as well. The upgrade of such systems may often be non-trivial and 463 costly. 465 4.5. DS-Lite 467 Dual-Stack Lite (DS-Lite, [RFC6333]) is based on a native IPv6 468 connection model where IPv4 services are supported. DS-Lite provides 469 tunneled connectivity for IPv4 over the IPv6 path between the 470 subscriber's network device and a provider managed gateway (AFTR). 472 DS-Lite can only be used where there is native IPv6 connection 473 between the AFTR and the CPE. This may mean that the technology's 474 use may not be viable during early transition if the core or access 475 network lacks IPv6 support. During the early transition period, a 476 significant amount of content and services may by IPv4-only. 477 Operators may be sensitive to this and may not want the newer IPv6 478 path to be the only bridge to IPv4 at that time given the potential 479 impact. The operator may also want to make sure that most of its 480 internal services and a significant about of external content is 481 available over IPv6 before deploying DS-Lite. The availability of 482 services on IPv6 would help lower the demand on the AFTRs. 484 By sharing IPv4 addresses among multiple endpoints, like CGN/NAT444, 485 DS-Lite can facilitate continued support of legacy IPv4 services even 486 after IPv4 address run out. There are some functional considerations 487 to take into account with DS-Lite, such as those described in 488 [I-D.donley-nat444-impacts]and in [I-D.ietf-softwire-dslite- 489 deployment]. 491 DS-Lite requires client support on the CPE to function. The ability 492 to utilize DS-Lite will be dependent on the operator providing DS- 493 Lite capable CPEs or retail availability of the supported client for 494 subscriber-acquired endpoints. 496 4.6. NAT64 498 NAT64 [RFC6146] provides the ability to connect IPv6-only connected 499 clients and hosts to IPv4 servers without any tunneling. NAT64 500 requires that the host and home network supports IPv6-only modes of 501 operation. Home networks do not commonly contain equipment that is 502 100% IPv6-capable. It is also not anticipated that common home 503 networks will be ready for IPv6-only operation for a number of years. 504 However, IPv6-only networking can be deployed by early adopters or 505 highly controlled networks [RFC6586]. 507 Viability of NAT64 will increase in wireline networks as consumer 508 equipment is replaced by IPv6 capable versions. There are incentives 509 for operators to move to IPv6-only operation, when feasible, which 510 includes the simplicity of a single stack access network. 512 5. IPv6 Transition Phases 514 The Phases described in this document are not provided as a rigid set 515 of steps, but are considered a guideline which should be analyzed by 516 operators planning their IPv6 transition. Operators may choose to 517 skip steps based on technological capabilities within their specific 518 networks, (residential/corporate, fixed/mobile), their business 519 development perspectives (which may affect the pace of migration 520 towards full IPv6), or a combination thereof. 522 The phases are based on the expectation that IPv6 traffic volume may 523 initially be low, and operator staff will gain experience with IPv6 524 over time. As traffic volumes of IPv6 increase, IPv4 traffic volumes 525 will decline (in percentage relative to IPv4), until IPv6 is the 526 dominant address family used. Operators may want to keep the traffic 527 flow for the dominant traffic class (IPv4 vs. IPv6) native to help 528 manage costs related to transition technologies. The cost of using 529 multiple technologies in succession to optimize each stage of the 530 transition should also be compared against the cost of changing and 531 upgrading subscriber connections. 533 Additional guidance and information on utilizing IPv6 transition 534 mechanisms can be found in [RFC6180]. Also, guidance on incremental 535 CGN for IPv6 transition can also be found in [RFC6264]. 537 5.1. Phase 0 - Foundation 539 5.1.1. Phase 0 - Foundation: Training 541 Training is one of the most important steps in preparing an 542 organization to support IPv6. Most people have little experience 543 with IPv6, and many do not even have a solid grounding in IPv4. The 544 implementation of IPv6 will likely produce many challenges due to 545 immature code on hardware, and the evolution of many applications and 546 systems to support IPv6. To properly deal with these impending or 547 current challenges, organizations must train their staff on IPv6. 549 Training should also be provided within reasonable timelines from the 550 actual IPv6 deployment. This means the operator needs to plan in 551 advance as it trains the various parts of its organization. New 552 Technology and Engineering staff often receive little training 553 because of their depth of knowledge, but must at least be provided 554 opportunities to read documentation, architectural white papers, and 555 RFCs. Operations personnel who support the network and other systems 556 need to be trained closer to the deployment timeframes, so they 557 immediately use their new-found knowledge before forgetting. 559 Subscriber support staff would require much more basic but large 560 scale training since many organizations have massive call centers to 561 support the subscriber base. Tailored training will also be required 562 for marketing and sales staff to help them understand IPv6 and build 563 it into the product development and sales process. 565 5.1.2. Phase 0 - Foundation: Routing 567 The network infrastructure will need to be in place to support IPv6. 568 This includes the routed infrastructure along with addressing 569 principles, routing principles, peering policy and related network 570 functions. Since IPv6 is quite different from IPv4 in several ways 571 including the number of addresses which are made available, careful 572 attention to a scalable and manageable architecture needs to be made. 573 One such change is the notion of a delegated prefix, which deviates 574 from the common single address phenomenon in IPv4-only deployments. 575 Deploying prefixes per CPE can load the routing tables and require a 576 routing protocol or route gleaning to manage connectivity to the 577 subscriber's network. Delegating prefixes can be of specific 578 importance in access network environments where downstream subscriber 579 often move between access nodes, raising the concern of frequent 580 renumbering and/or managing movement of routed prefixes within the 581 network (common in cable based networks). 583 5.1.3. Phase 0 - Foundation: Network Policy and Security 585 Many, but not all, security policies will map easily from IPv4 to 586 IPv6. Some new policies may be required for issues specific to IPv6 587 operation. This document does not highlight these specific issues, 588 but raises the awareness they are of consideration and should be 589 addressed when delivering IPv6 services. Other IETF documents such 590 as [RFC4942], [RFC6092], and [RFC6169] are excellent resources. 592 5.1.4. Phase 0 - Foundation: Transition Architecture 594 The operators should plan out their transition architecture in 595 advance (with room for flexibility) to help optimize how they will 596 build out and scale their networks. Should the operator consider 597 multiple technologies like CGN/NAT444, DS-Lite, NAT64 and 6RD, they 598 may want to plan out where network resident equipment may be located 599 and potentially choose locations which can be used for all functional 600 roles (i.e. Placement of NAT44 translator, AFTR, NAT64 gateway and 601 6RD relays). Although these functions are not inherently connected, 602 additional management, diagnostic and monitoring functions can be 603 deployed along side the transition hardware without the need to 604 distribute these to an excessive or divergent number of locations. 606 This approach may also prove beneficial if traffic patterns change 607 rapidly in the future as the operators may need to evolve their 608 transition infrastructure faster than originally anticipated. Once 609 such example may be the movement from a CGN/NAT44 model (dual stack) 610 to DS-Lite. Since both traffic sets require a translation function 611 (NAT44), synchronized pool management, routing and management system 612 positioning can allow rapid movement (notwithstanding the 613 technological means to re-provision the subscriber). 615 Operators should inform their vendors of what technologies they plan 616 to support over the course of the transition to make sure the 617 equipment is suited to support those modes of operation. This is 618 important for both network gear and subscriber premise equipment. 620 The operator should also plan their overall strategy to meet the 621 target needs of an IPv6-only deployment. As traffic moves to IPv6, 622 the benefits of only a single stack on the access network may 623 eventually justify the removal of IPv4 for simplicity. Planning for 624 this eventual model, no matter how far off this may be, will help the 625 operator embrace this end state when needed. 627 5.1.5. Phase 0- Foundation: Tools and Management 629 The operator should thoroughly analyze all provisioning and 630 management systems to develop requirements for each phase. This will 631 include concepts related to the 128-bit IPv6 address, the notation of 632 an assigned IPv6 prefix (Prefix Delegation) and the ability to detect 633 either or both address families when determining if a subscriber has 634 full Internet service. 636 If an operator stores usage information, this would need to be 637 aggregated to include both the IPv4 and IPv6 as both address families 638 are assigned to the same subscriber. Tools that verify connectivity 639 may need to query the IPv4 and IPv6 addresses. 641 5.2. Phase 1 - Tunneled IPv6 643 Tunneled access to IPv6 can be regarded as an early stage transition 644 option by operators. Many network operators can deploy native IPv6 645 from the access edge to the peering edge fairly quickly but may not 646 be able to offer IPv6 natively to the subscriber edge device. During 647 this period of time, tunneled access to IPv6 is a viable alternative 648 to native IPv6. It is also possible that operators may be rolling 649 out IPv6 natively to the subscriber edge but the time involved may be 650 long due to logistics and other factors. Even while carefully 651 rolling out native IPv6, operators can deploy relays for automatic 652 tunneling technologies like 6to4 and Teredo. Where native IPv6 to 653 the access edge is a longer-term project, operators can consider 6RD 654 [RFC5969] as an option to offer in-home IPv6 access. Note that 6to4 655 and Teredo have different address selection behaviors than 6RD 656 [RFC3484]. Additional guidelines on deploying and supporting 6to4 657 can be found in [RFC6343]. 659 The operator can deploy 6RD relays into the network and scale them as 660 needed to meet the early subscriber needs of IPv6. Since 6RD 661 requires the upgrade or replacement of CPE devices, the operator may 662 want to ensure that the CPE devices support not just 6RD but native 663 Dual Stack and other tunneling technologies if possible such as DS- 664 Lite [I-D.ietf-v6ops-6204bis]. 6RD clients are becoming available in 665 some retail channel products and within the OEM market. Retail 666 availability of 6RD is important since not all operators control or 667 have influence over what equipment is deployed in the consumer home 668 network. The operator can support 6RD access with unmanaged devices 669 using DHCPv4 option 212 (OPTION_6RD) [RFC5969]. 671 +--------+ ----- 672 | | / \ 673 Encap IPv6 Flow | 6RD | | IPv6 | 674 - - -> | BR | <- > | Net | 675 +---------+ / | | \ / 676 | | / +--------+ ----- 677 | 6RD + <----- ----- 678 | | / \ 679 | Client | IPv4 Flow | IPv4 | 680 | + < - - - - - - - - - - - - - - -> | Net | 681 | | \ / 682 +---------+ ----- 684 Figure 1: 6RD Basic Model 686 6RD used as an initial transition technology also provides the added 687 benefit of a deterministic IPv6 prefix based on the IPv4 assigned 688 address. Many operational tools are available or have been built to 689 identify what IPv4 (often dynamic) address was assigned to a 690 subscriber CPE. So, a simple tool and/or method can be built to help 691 identify the IPv6 prefix using the knowledge of the assigned IPv4 692 address. 694 An operator may choose to not offer internal services over IPv6 if 695 tunneled access to IPv6 is used since some services generate a large 696 amount of traffic. Such traffic may include Video content like IPTV. 697 By limiting how much traffic is delivered over the 6RD connection (if 698 possible), the operator can avoid costly and complex scaling of the 699 relay infrastructure. 701 5.2.1. 6RD Deployment Considerations 703 Deploying 6RD can greatly speed up an operator's ability to support 704 IPv6 to the subscriber network if native IPv6 connectivity cannot be 705 supplied. The speed at which 6RD can be deployed is highlighted in 706 [RFC5569]. 708 The first core consideration is deployment models. 6RD requires the 709 CPE (6RD client) to send traffic to a 6RD relay. These relays can 710 share a common anycast address, or can use unique addresses. Using 711 an anycast model, the operator can deploy all the 6RD relays using 712 the same IPv4 interior service address. As the load increases on the 713 deployed relays, the operator can deploy more relays into the 714 network. The one drawback is that it may be difficult to manage the 715 traffic volume among additional relays, since all 6RD traffic will 716 find the nearest (in terms of IGP cost) relay. Use of multiple relay 717 addresses can help provide more control but has the disadvantage of 718 being more complex to provision. Subsets of CPEs across the network 719 will require and contain different relay information. An alternative 720 approach is to use a hybrid model using multiple anycast service IP 721 Addresses for clusters of 6RD relays, should the operator anticipate 722 massive scaling of the environment. Thus, the operator has multiple 723 vectors by which to scale the service. 725 +--------+ 726 | | 727 IPv4 Addr.X | 6RD | 728 - - - > | BR | 729 +-----------+ / | | 730 | Client A | <- - - +--------+ 731 +-----------+ 732 Separate IPv4 Service Addresses 733 +-----------+ 734 | Client B | < - - +--------+ 735 +-----------+ \ | | 736 - - - > | 6RD | 737 IPv4 Addr.Y | BR | 738 | | 739 +--------+ 741 Figure 2: 6RD Multiple IPv4 Service Address Model 743 +--------+ 744 | | 745 IPv4 Addr.X | 6RD | 746 - - - > | BR | 747 +-----------+ / | | 748 | Client A |- - - - +--------+ 749 +-----------+ 750 Common (Anycast) IPv4 Service Addresses 751 +-----------+ 752 | Client B | - - - +--------+ 753 +-----------+ \ | | 754 - - - > | 6RD | 755 IPv4 Addr.X | BR | 756 | | 757 +--------+ 759 Figure 3: 6RD Anycast IPv4 Service Address Model 761 Provisioning of the 6RD endpoints is affected by the deployment model 762 chosen (i.e. anycast vs. specific service IP Addresses). Using 763 multiple IP Addresses may require more planning and management, as 764 subscriber equipment will have different sets of data to be 765 provisioned into the devices. The operator may use DHCPv4, manual 766 provisioning or other mechanisms to provide parameters to subscriber 767 equipment. 769 If the operator manages the CPE, support personnel will need tools 770 able to report the status of the 6RD tunnel. Usage information can 771 be counted on the operator edge, but if it requires source/ 772 destination flow details, data must be collected after the 6RD relay 773 (IPv6 side of connection). 775 6RD [RFC5969], as any tunneling option, is subject to a reduced MTU 776 so operators need to plan to manage this environment. 778 +---------+ IPv4 Encapsulation +------------+ 779 | +- - - - - - - - - - - + | 780 | 6RD +----------------------+ 6RD +--------- 781 | | IPv6 Packet | Relay | IPv6 Packet 782 | Client +----------------------+ +--------- 783 | +- - - - - - - - - - - + | ^ 784 +---------+ ^ +------------+ | 785 | | 786 | | 787 IPv4 IP (Tools/Mgmt) IPv6 Flow Analysis 789 Figure 4: 6RD Tools and Flow Management 791 5.3. Phase 2: Native Dual Stack 793 Either as a follow-up phase to "Tunneled IPv6" or as an initial step, 794 the operator may deploy native IPv6 down to the CPEs. This phase 795 would then allow for both IPv6 and IPv4 to be natively accessed by 796 the subscriber home network without translation or tunneling. The 797 native Dual Stack phase can be rolled out across the network while 798 the tunneled IPv6 service remains operational, if used. As areas 799 begin to support native IPv6, subscriber home equipment will 800 generally prefer using the IPv6 addresses derived from the delegated 801 IPv6 prefix versus tunneling options such as 6to4 and Teredo as 802 defined in [RFC3484]. Specific care is needed when moving to native 803 Dual Stack from 6RD as documented in 804 [I-D.townsley-v6ops-6rd-sunsetting]. 806 Native Dual Stack is the best option at this point in the transition, 807 and should be sought as soon as possible. During this phase, the 808 operator can confidently move both internal and external services to 809 IPv6. Since there are no translation devices needed for this mode of 810 operation, it transports both protocols (IPv6 and IPv4) efficiently 811 within the network. 813 5.3.1. Native Dual Stack Deployment Considerations 815 Native Dual Stack is a very desirable option for the IPv6 transition, 816 if feasible. The operator must enable IPv6 on the network core and 817 peering edge before they attempt to turn on native IPv6 services. 818 Additionally, provisioning and support systems such as DHCPv6, DNS 819 and other functions that support the subscriber's IPv6 Internet 820 connection need to be in place. 822 The operator must treat IPv6 connectivity with the same operational 823 importance as IPv4. A poor IPv6 service may be worse than not 824 offering an IPv6 service at all as it will negatively impact the 825 subscriber's Internet experience. This may cause users or support 826 personnel to disable IPv6, limiting the subscriber from the benefits 827 of IPv6 connectivity as the network performance improves. New code 828 and IPv6 functionality may cause instability at first. The operator 829 will need to monitor, troubleshoot and resolve issues promptly. 831 Prefix assignment and routing are new for common residential 832 services. Prefix assignment is straightforward (DHCPv6 using 833 IA_PDs), but installation and propagation of routing information for 834 the prefix, especially during access layer instability, is often 835 poorly understood. The operator should develop processes for 836 renumbering subscribers who move to new access nodes. 838 Operators need to keep track of both the dynamically assigned IPv4 839 address along with the IPv6 address and prefix. Any additional 840 dynamic elements, such as auto-generated host names, need to be 841 considered and planned for. 843 5.4. Intermediate Phase for CGN 845 Acquiring more IPv4 addresses is already challenging, if not 846 impossible; therefore address sharing may be required on the IPv4 847 path. The operator may have a preference to move directly to a 848 transition technology such as DS-Lite [RFC6333] or may choose CGN/ 849 NAT444 to facilitate IPv4 connections. CGN/NAT444 requires IPv4 850 addressing between the subscriber premise equipment and the 851 operator's translator which may be facilitated by shared address 852 [RFC6598], private address [RFC1918] or other address space. CGN/ 853 NAT444 should be used cautiously if used simultaneously with 6RD for 854 a common set of subscribers. Operators should be aware that if CGN/ 855 NAT444 is used in such manner, subscriber all traffic must traverse 856 some type of operator service node (relay and translator). Also, 857 care should be taken so as not to run 6RD through a DS-Lite tunnel or 858 vice versa. 860 +--------+ ----- 861 | | / \ 862 IPv4 Flow | CGN | | | 863 - - -> + + < -> | | 864 +---------+ / | | | | 865 | CPE | <- - - / +--------+ | IPv4 | 866 |---------+ | Net | 867 | | 868 +---------+ IPv4 Flow | | 869 | CPE | <- - - - - - - - - - - - - - - > | | 870 |---------+ \ / 871 ----- 873 Figure 5: Overlay CGN Deployment 875 In the case of native Dual Stack, CGN/NAT444 can be used to assist in 876 extending connectivity for the IPv4 path while the IPv6 path remains 877 native. For endpoints operating in a IPv6+CGN/NAT444 model, the 878 native IPv6 path is available for higher quality connectivity, 879 helping host operation over the network. At the same time, the CGN 880 path may offer a less than optimal performance. These points are 881 also true for DS-Lite. 883 +--------+ ----- 884 | | / \ 885 IPv4 Flow | CGN | | IPv4 | 886 - - -> + + < -> | Net | 887 +---------+ / | | \ / 888 | | <- - - / +--------+ ------- 889 | Dual | 890 | Stack | ----- 891 | CPE | IPv6 Flow / IPv6 \ 892 | | <- - - - - - - - - - - - - - - > | Net | 893 |---------+ \ / 894 ----- 896 Figure 6: Dual Stack with CGN 898 CGN/NAT444 deployments may make use of a number of address options, 899 which include [RFC1918] or Shared Address Space [RFC6598]. It is 900 also possible that operators may use part of their own RIR assigned 901 address space for CGN zone addressing if [RFC1918] addresses pose 902 technical challenges in their network. It is not recommended that 903 operators use 'squat space', as it may pose additional challenges 904 with filtering and policy control [RFC6598]. 906 5.4.1. CGN Deployment Considerations 908 CGN is often considered undesirable by operators but required in many 909 cases. An operator who needs to deploy CGN capabilities should 910 consider the impacts of the function to the network. CGN is often 911 deployed in addition to running IPv4 services and should not 912 negatively impact the already working Native IPv4 service. CGNs will 913 be needed at low scale at first and grown to meet the demands based 914 on traffic and connection dynamics of the subscriber, content and 915 network peers. 917 The operator may want to deploy CGNs more centrally at first and then 918 scale the system as needed. This approach can help conserve costs of 919 the system limiting the deploy based and scaling it based on actual 920 traffic demand. The operator should use a deployment model and 921 architecture which allows the system to scale as needed. 923 +--------+ ----- 924 | | / \ 925 | CGN | | | 926 - - -> + + < -> | | 927 +---------+ / | | | | 928 | CPE | <- - - / +--------+ | IPv4 | 929 | | ^ | | 930 |---------+ | | Net | 931 +--------+ Centralized | | 932 +---------+ | | CGN | | 933 | | | CGN | | | 934 | CPE | <- > + + <- - - - - - - > | | 935 |---------+ | | \ / 936 +--------+ ----- 937 ^ 938 | 939 Distributed CGN 941 Figure 7: CGN Deployment: Centralized vs. Distributed 943 The operator may be required to log translation information 944 [I-D.ietf-behave-lsn-requirements]. This logging may require 945 significant investment in external systems which ingest, aggregate 946 and report on such information [I-D.donley-behave-deterministic-cgn]. 948 Since CGN has noticeable impacts on certain applications [I-D.donley- 949 nat444-impacts], operators may deploy CGN only for those subscribers 950 who may be less affected by CGN (if possible). 952 5.5. Phase 3 - IPv6-Only 954 Once Native IPv6 is widely deployed in the network and well-supported 955 by tools, staff, and processes, an operator may consider supporting 956 only IPv6 to all or some subscriber endpoints. During this final 957 phase, IPv4 connectivity may or may not need to be supported, 958 depending on the conditions of the network and subscriber demand. If 959 legacy IPv4 connectivity is still demanded (e.g. for older nodes), 960 DS-Lite [RFC6333] may be used to tunnel the traffic. If IPv4 961 connectivity is not required, but access to legacy IPv4 content is, 962 then NAT64 [RFC6144][RFC6146] can be used. 964 DS-Lite allows continued access for the IPv4 subscriber base using 965 address sharing for IPv4 Internet connectivity, but with only a 966 single layer of translation, compared to CGN/NAT444. This mode of 967 operation also removes the need to directly supply subscriber 968 endpoints with an IPv4 address, potentially simplifying the 969 connectivity to the customer (single address family) and supporting 970 IPv6 only addressing to the CPE. 972 The operator can also move Dual Stack endpoints to DS-Lite 973 retroactively to help optimize the IPv4 address sharing deployment by 974 removing the IPv4 address assignment and routing component. To 975 minimize traffic needing translation, the operator should have 976 already moved most content to IPv6 before the IPv6-only phase is 977 implemented. 978 +--------+ ----- 979 | | / \ 980 Encap IPv4 Flow | AFTR | | IPv4 | 981 -------+ +---+ Net | 982 +---------+ / | | \ / 983 | | / +--------+ ----- 984 | DS-Lite +------- ----- 985 | | / \ 986 | Client | IPv6 Flow | IPv6 | 987 | +-------------------------------| Net | 988 | | \ / 989 +---------+ ----- 991 Figure 8: DS-Lite Basic Model 993 If the operator had previously decided to enable a CGN/NAT444 994 deployment, it may be able to co-locate the AFTR and CGN/NAT444 995 processing functions within a common network location to simplify 996 capacity management and the engineering of flows. This case may be 997 evident in a later transition stages when an operator chooses to 998 optimize its network and IPv6-only operation is feasible. 1000 5.5.1. DS-Lite Deployment Considerations 1002 The same deployment considerations associated with Native IPv6 1003 deployments apply to DS-Lite and NAT64. IPv4 will now be dependent 1004 on IPv6 service quality, so the IPv6 network and services must be 1005 running well to ensure a quality experience for the end subscriber. 1006 Tools and processes will be needed to manage the encapsulated IPv4 1007 service. If flow analysis is required for IPv4 traffic, this may be 1008 enabled at a point beyond the AFTR (after de-capsulation) or DS-Lite 1009 [RFC6333] aware equipment is used to process traffic midstream. 1011 +---------+ IPv6 Encapsulation +------------+ 1012 | + - - - - - - - - - - -+ | 1013 | AFTR +----------------------+ AFTR +--------- 1014 | | IPv4 Packet | | IPv4 Packet 1015 | Client +----------------------+ +--------- 1016 | + - - - - - - - - - - -+ | ^ 1017 +---------+ ^ ^ +------------+ | 1018 | | | 1019 | | | 1020 IPv6 IP (Tools/Mgmt) | IPv4 Packet Flow Analysis 1021 | 1022 Midstream IPv4 Packet Flow Analysis (Encapsulation Aware) 1024 Figure 9: DS-Lite Tools and Flow Analysis 1026 DS-Lite [RFC6333] also requires client support on the subscribers 1027 premise device. The operator must clearly articulate to vendors 1028 which technologies will be used at which points, how they interact 1029 with each other at the CPE, and how they will be provisioned. As an 1030 example, an operator may use 6RD in the outset of the transition, 1031 then move to Native Dual Stack followed by DS-Lite. 1033 DS-Lite [RFC6333], as any tunneling option, is subject to a reduced 1034 MTU so operators need to plan to manage this environment. Additional 1035 considerations for DS-Lite deployments can be found in 1036 [I-D.ietf-softwire-dslite-deployment]. 1038 5.5.2. NAT64 Deployment Considerations 1040 The deployment of NAT64 assumes the network assigns an IPv6 address 1041 to a network endpoint that is translated to an IPv4 address to 1042 provide connectivity to IPv4 Internet services and content. 1043 Experiments such as the one described in [RFC6586] highlight issues 1044 related to IPv6-only deployments due to legacy IPv4 APIs and IPv4 1045 literals. Many of these issues will be resolved by the eventual 1046 removal this undesired legacy behavior. Operational deployment 1047 models, considerations and experiences related to NAT64 have been 1048 documented in [I-D.chen-v6ops-nat64-experience]. 1050 +--------+ ----- 1051 | | / \ 1052 IPv6 Flow | NAT64 | | IPv4 | 1053 -------+ DNS64 +---+ Net | 1054 +---------+ / | | \ / 1055 | | / +--------+ ----- 1056 | IPv6 +------- ----- 1057 | | / \ 1058 | Only | IPv6 Flow | IPv6 | 1059 | +-------------------------------| Net | 1060 | | \ / 1061 +---------+ ----- 1063 Figure 10: NAT64/DNS64 Basic Model 1065 To navigate around some of the limitations of NAT64 when dealing with 1066 legacy IPv4 applications, the operator may choose to implement 1067 464XLAT [I-D.ietf-v6ops-464xlat] if possible. As support for IPv6 on 1068 subscriber equipment and content increases, the efficiency of NAT64 1069 increases by reducing the need to translate traffic. The NAT64 1070 deployment would see an overall decline in usage as more traffic is 1071 promoted to IPv6-to-IPv6 native communication. NAT64 may play an 1072 important part of an operator's late stage transition, as it removes 1073 the need to support IPv4 on the access network and provides a solid 1074 go-forward networking model. 1076 It should be noted, as with any technology which utilizes address 1077 sharing, that the IPv4 public pool sizes (IPv4 transport addresses 1078 per [RFC6146]) can pose limits to IPv4 server connectivity for the 1079 subscriber base. Operators should be aware that some IPv4 growth in 1080 the near term is possible, so IPv4 translation pools need to be 1081 monitored. 1083 6. IANA Considerations 1085 No IANA considerations are defined at this time. 1087 7. Security Considerations 1089 Operators should review the documentation related to the technologies 1090 selected for IPv6 transition. In those reviews, operators should 1091 understand what security considerations are applicable to the chosen 1092 technologies. As an example, [RFC6169] should be reviewed to 1093 understand security considerations around tunnelling technologies. 1095 8. Acknowledgements 1097 Special thanks to Wes George, Chris Donley, Christian Jacquenet and 1098 John Brzozowski for their extensive review and comments. 1100 Thanks to the following people for their textual contributions, 1101 guidance and comments: Jason Weil, Gang Chen, Nik Lavorato, John 1102 Cianfarani, Chris Donley, Tina TSOU, Fred Baker and Randy Bush. 1104 9. References 1106 9.1. Normative References 1108 [RFC6180] Arkko, J. and F. Baker, "Guidelines for Using IPv6 1109 Transition Mechanisms during IPv6 Deployment", RFC 6180, 1110 May 2011. 1112 9.2. Informative References 1114 [I-D.chen-v6ops-nat64-experience] 1115 Chen, G., Cao, Z., Byrne, C., Xie, C., and D. Binet, 1116 "NAT64 Operational Experiences", 1117 draft-chen-v6ops-nat64-experience-02 (work in progress), 1118 July 2012. 1120 [I-D.donley-behave-deterministic-cgn] 1121 Donley, C., Grundemann, C., Sarawat, V., and K. 1122 Sundaresan, "Deterministic Address Mapping to Reduce 1123 Logging in Carrier Grade NAT Deployments", 1124 draft-donley-behave-deterministic-cgn-03 (work in 1125 progress), June 2012. 1127 [I-D.donley-nat444-impacts] 1128 Donley, C., Howard, L., Kuarsingh, V., Berg, J., and U. 1129 Colorado, "Assessing the Impact of Carrier-Grade NAT on 1130 Network Applications", draft-donley-nat444-impacts-04 1131 (work in progress), May 2012. 1133 [I-D.ietf-behave-lsn-requirements] 1134 Perreault, S., Yamagata, I., Miyakawa, S., Nakagawa, A., 1135 and H. Ashida, "Common requirements for Carrier Grade NATs 1136 (CGNs)", draft-ietf-behave-lsn-requirements-07 (work in 1137 progress), June 2012. 1139 [I-D.ietf-softwire-dslite-deployment] 1140 Lee, Y., Maglione, R., Williams, C., Jacquenet, C., and M. 1141 Boucadair, "Deployment Considerations for Dual-Stack 1142 Lite", draft-ietf-softwire-dslite-deployment-03 (work in 1143 progress), March 2012. 1145 [I-D.ietf-v6ops-464xlat] 1146 Mawatari, M., Kawashima, M., and C. Byrne, "464XLAT: 1147 Combination of Stateful and Stateless Translation", 1148 draft-ietf-v6ops-464xlat-05 (work in progress), July 2012. 1150 [I-D.ietf-v6ops-6204bis] 1151 Singh, H., Beebee, W., Donley, C., and B. Stark, "Basic 1152 Requirements for IPv6 Customer Edge Routers", 1153 draft-ietf-v6ops-6204bis-09 (work in progress), May 2012. 1155 [I-D.jjmb-v6ops-comcast-ipv6-experiences] 1156 Brzozowski, J. and C. Griffiths, "Comcast IPv6 Trial/ 1157 Deployment Experiences", 1158 draft-jjmb-v6ops-comcast-ipv6-experiences-02 (work in 1159 progress), October 2011. 1161 [I-D.kuarsingh-v6ops-6to4-provider-managed-tunnel] 1162 Kuarsingh, V., Lee, Y., and O. Vautrin, "6to4 Provider 1163 Managed Tunnels", 1164 draft-kuarsingh-v6ops-6to4-provider-managed-tunnel-07 1165 (work in progress), July 2012. 1167 [I-D.townsley-v6ops-6rd-sunsetting] 1168 Cassen, A. and M. Townsley, "6rd Sunsetting", 1169 draft-townsley-v6ops-6rd-sunsetting-00 (work in progress), 1170 November 2011. 1172 [RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and 1173 E. Lear, "Address Allocation for Private Internets", 1174 BCP 5, RFC 1918, February 1996. 1176 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1177 (IPv6) Specification", RFC 2460, December 1998. 1179 [RFC3056] Carpenter, B. and K. Moore, "Connection of IPv6 Domains 1180 via IPv4 Clouds", RFC 3056, February 2001. 1182 [RFC3068] Huitema, C., "An Anycast Prefix for 6to4 Relay Routers", 1183 RFC 3068, June 2001. 1185 [RFC3484] Draves, R., "Default Address Selection for Internet 1186 Protocol version 6 (IPv6)", RFC 3484, February 2003. 1188 [RFC4380] Huitema, C., "Teredo: Tunneling IPv6 over UDP through 1189 Network Address Translations (NATs)", RFC 4380, 1190 February 2006. 1192 [RFC4942] Davies, E., Krishnan, S., and P. Savola, "IPv6 Transition/ 1193 Co-existence Security Considerations", RFC 4942, 1194 September 2007. 1196 [RFC5569] Despres, R., "IPv6 Rapid Deployment on IPv4 1197 Infrastructures (6rd)", RFC 5569, January 2010. 1199 [RFC5969] Townsley, W. and O. Troan, "IPv6 Rapid Deployment on IPv4 1200 Infrastructures (6rd) -- Protocol Specification", 1201 RFC 5969, August 2010. 1203 [RFC6092] Woodyatt, J., "Recommended Simple Security Capabilities in 1204 Customer Premises Equipment (CPE) for Providing 1205 Residential IPv6 Internet Service", RFC 6092, 1206 January 2011. 1208 [RFC6144] Baker, F., Li, X., Bao, C., and K. Yin, "Framework for 1209 IPv4/IPv6 Translation", RFC 6144, April 2011. 1211 [RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful 1212 NAT64: Network Address and Protocol Translation from IPv6 1213 Clients to IPv4 Servers", RFC 6146, April 2011. 1215 [RFC6169] Krishnan, S., Thaler, D., and J. Hoagland, "Security 1216 Concerns with IP Tunneling", RFC 6169, April 2011. 1218 [RFC6264] Jiang, S., Guo, D., and B. Carpenter, "An Incremental 1219 Carrier-Grade NAT (CGN) for IPv6 Transition", RFC 6264, 1220 June 2011. 1222 [RFC6269] Ford, M., Boucadair, M., Durand, A., Levis, P., and P. 1223 Roberts, "Issues with IP Address Sharing", RFC 6269, 1224 June 2011. 1226 [RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual- 1227 Stack Lite Broadband Deployments Following IPv4 1228 Exhaustion", RFC 6333, August 2011. 1230 [RFC6343] Carpenter, B., "Advisory Guidelines for 6to4 Deployment", 1231 RFC 6343, August 2011. 1233 [RFC6540] George, W., Donley, C., Liljenstolpe, C., and L. Howard, 1234 "IPv6 Support Required for All IP-Capable Nodes", BCP 177, 1235 RFC 6540, April 2012. 1237 [RFC6586] Arkko, J. and A. Keranen, "Experiences from an IPv6-Only 1238 Network", RFC 6586, April 2012. 1240 [RFC6598] Weil, J., Kuarsingh, V., Donley, C., Liljenstolpe, C., and 1241 M. Azinger, "IANA-Reserved IPv4 Prefix for Shared Address 1242 Space", BCP 153, RFC 6598, April 2012. 1244 Authors' Addresses 1246 Victor Kuarsingh (editor) 1247 Rogers Communications 1248 8200 Dixie Road 1249 Brampton, Ontario L6T 0C1 1250 Canada 1252 Email: victor.kuarsingh@gmail.com 1253 URI: http://www.rogers.com 1255 Lee Howard 1256 Time Warner Cable 1257 13820 Sunrise Valley Drive 1258 Herndon, VA 20171 1259 US 1261 Email: lee.howard@twcable.com 1262 URI: http://www.timewarnercable.com