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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: November 24, 2012 Time Warner Cable 6 May 23, 2012 8 Wireline Incremental IPv6 9 draft-ietf-v6ops-wireline-incremental-ipv6-03 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 November 24, 2012. 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 . . . . . . . . . . . . . . . . . . . . . 24 94 7. Security Considerations . . . . . . . . . . . . . . . . . . . 24 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 - Many access network devices or subscriber controlled CPEs may 181 not support native IPv6 operation for a period of time. [RFC6540] 182 should remedy the situation over time as the document requires 183 IPv6 support for all IP-capable nodes 185 - Connectivity modes will move from IPv4-only to Dual Stack in the 186 home, changing functional behaviors in the consumer network and 187 increasing support requirements for the operator 189 These challenges will occur over a period of time, which means that 190 the operator's plans need to address the ever changing requirements 191 of the network and subscriber demand. Although phases will be 192 presented in this document, not all operators may need to enable each 193 discrete phase. It is possible that characteristics in individual 194 networks may allow certain operators to skip or jump to various 195 phases. 197 3.1. Relevance of IPv6 and IPv4 199 The delivery of high-quality unencumbered Internet service should be 200 the primary goal for operators. It is recognized that with the 201 imminent exhaustion of IPv4, IPv6 will offer the highest quality of 202 experience in the long term. Even though the operator may be focused 203 on IPv6 delivery, they should be aware that both IPv4 and IPv6 will 204 play a role in the Internet experience during transition. The 205 Internet is made of many interconnecting systems, networks, hardware, 206 software and content sources - all of which will move to IPv6 at 207 different rates. 209 Many subscribers use older operating systems and hardware which 210 support IPv4-only operation. Internet subscribers don't buy IPv4 or 211 IPv6 connections; they buy Internet connections, which demands the 212 need to support both IPv4 and IPv6 for as long at the subscriber's 213 home network demands such support. The operator may be able to 214 leverage one or the other protocol to help bridge connectivity on the 215 operator's network, but the home network will likely demand both IPv4 216 and IPv6 for some time. 218 3.2. IPv4 Resource Challenges 220 Since connectivity to IPv4-only endpoints and/or content will remain 221 common, IPv4 resource challenges are of key concern to operators. 222 The lack of new IPv4 addresses for additional devices means that 223 meeting the growth in demand of IPv4 connections in some networks 224 will require address sharing. 226 Networks are growing at different rates including those in emerging 227 markets and established networks based on the proliferation of 228 Internet based services and devices. IPv4 address constraints will 229 likely affect many if not most operators at some point, increasing 230 the benefits of IPv6. IPv4 address exhaustion is a consideration 231 when selecting technologies which rely on IPv4 to supply IPv6 232 services, such as 6RD. Additionally, if native Dual Stack is 233 considered by the operator, challenges related to IPv4 address 234 exhaustion remain a concern. 236 Some operators may be able to reclaim small amounts IPv4 addresses 237 through addressing efficiencies in the network, although this will 238 have little lasting benefits to the network and not meet longer term 239 connectivity needs. The lack of new global IPv4 address allocations 240 will therefore force operators to support some form of IPv4 address 241 sharing and may impact technological options for transition once the 242 operator runs out of new IPv4 addresses for assignment. 244 3.3. IPv6 Introduction and Operational Maturity 246 The introduction of IPv6 will require new operational practices. The 247 IPv4 environment we have today was built over many years and matured 248 by experience. Although many of these experiences are transferable 249 from IPv4 to IPv6, new experience and practices specific to IPv6 will 250 be needed. 252 Engineering and Operational staff will need to develop experience 253 with IPv6. Inexperience may lead to early IPv6 deployment 254 instability, and operators should consider this when selecting 255 technologies for initial transition. Operators may not want to 256 subject their mature IPv4 service to a "new IPv6" path initially 257 while it may be going through growing pains. DS-Lite [RFC6333] and 258 NAT64 [RFC6146] are both technologies which requires IPv6 to support 259 connectivity to IPv4 endpoints or content over an IPv6-only access 260 network. 262 Further, some of these transition technologies are new and require 263 refinement within running code. Deployment experience is required to 264 expose bugs and stabilize software in production environments. Many 265 supporting systems are also under development and have newly 266 developed IPv6 functionality including vendor implementations of 267 DHCPv6, management tools, monitoring systems, diagnostic systems, 268 logging, along with other elements. 270 Although the base technological capabilities exist to enable and run 271 IPv6 in most environments, organizational experience is low. Until 272 such time as each key technical member of an operator's organization 273 can identify IPv6, understand its relevance to the IP service 274 offering, how it operates and how to troubleshoot it, the deployment 275 needs to mature, and may be subject to subscriber-impacting events. 276 This fact should not incline operators to delay their IPv6 277 deployment, but should drive them to deploy IPv6 sooner to gain the 278 much needed experience before IPv6 is the only viable way to connect 279 new hosts to the network. 281 It should also be noted that although many transition technologies 282 may be new, and some code related to access environments may be new, 283 there is a large segment of the networking fabric which has had IPv6 284 available for a long period of time and has had extended exposure in 285 production. Operators may use this to their advantage by first 286 enabling IPv6 in the core of their network then work outward towards 287 the subscriber edge. 289 3.4. Service Management 291 Services are managed within most networks and are often based on the 292 gleaning and monitoring of IPv4 addresses assigned to endpoints. 293 Operators will need to address such management tools, troubleshooting 294 methods and storage facilities (such as databases) to deal with not 295 just a new address type containing a 128-bit IPv6 address [RFC2460], 296 but often both IPv4 and IPv6 at the same time. Examination of 297 address type, and recording delegated prefixes along with single 298 address assignments, will likely require additional development. 300 With any Dual Stack service - whether Native, 6RD-based, DS-Lite, 301 NAT64 or otherwise - two address families may need to be managed 302 simultaneously to help provide for the full Internet experience. 303 This would indicate that IPv6 management is not just a simple add in, 304 but needs to be well integrated into the service management 305 infrastructure. In the early transition phases, it's quite likely 306 that many systems will be missed and that IPv6 services will go un- 307 monitored and impairments undetected. 309 These issues may be of consideration when selecting technologies that 310 require IPv6 as the base protocol to delivery IPv4 connectivity. 311 Instability on the IPv6 service in such a case would impact IPv4 312 services. 314 3.5. Sub-Optimal Operation of Transition Technologies 316 Native delivery of IPv4 and IPv6 provides a solid foundation for 317 delivery of Internet services to subscribers since native IP paths 318 are well understood and networks are often optimized to send such 319 traffic efficiently. Transition technologies however, may alter the 320 normal path of traffic or reduce the path MTU, removing many network 321 efficiencies built for native IP flows. Tunneling and translation 322 devices may not be located on the most optimal path in line with the 323 natural traffic flow (based on route computation) and therefore may 324 increase latency. These paths may also add additional points of 325 failure. 327 Generally, the operator will want to deliver native IPv6 as soon as 328 possible and utilize transition technologies only when required. 329 Transition technologies may be used to provide continued access to 330 IPv4 via tunneling and/or translation or may be used to deliver IPv6 331 connectivity. The delivery of Internet or internal services should 332 be considered by the operator, since supplying connections using a 333 transition technology will reduce the overall performance for the 334 subscriber. 336 When choosing between various transition technologies, operators 337 should consider the benefits and drawbacks of each option. Some 338 technologies like CGN/NAT444 utilize many existing addressing and 339 management practices. Other options such as DS-Lite and NAT64 remove 340 the IPv4 addressing requirement to the subscriber premise device but 341 require IPv6 to be operational and well supported. 343 3.6. Future IPv6 Network 345 An operator should also be aware that longer-term plans may include 346 IPv6-only operation in all or much of the network. The IPv6-only 347 operation may be complemented by technologies such as NAT64 for long- 348 tail IPv4 content reach. This longer term view may be distant to 349 some, but should be considered when planning out networks, addressing 350 and services. The needs and costs of maintaining two IP stacks will 351 eventually become burdensome and simplification will be desirable. 352 The operators should plan for this state and not make IPv6 inherently 353 dependent on IPv4 as this would unnecessarily constrain the network. 355 4. IPv6 Transition Technology Analysis 357 Operators should understand the main transition technologies for IPv6 358 deployment and IPv4 runout. This draft provides a brief description 359 of some of the mainstream and commercially available options. This 360 analysis is focused on the applicability of technologies to deliver 361 residential services and less focused on commercial access, wireless, 362 or infrastructure support. 364 The technologies in focus for this document are targeted on those 365 commercially available and in deployment. 367 4.1. Automatic Tunneling using 6to4 and Teredo 369 Even when operators may not be actively deploying IPv6, automatic 370 mechanisms exist on subscriber operating systems and CPE hardware. 371 Such technologies include 6to4 [RFC3056], which is most commonly used 372 with anycast relays [RFC3068]. Teredo [RFC4380] is also used widely 373 by many Internet hosts. 375 Documents such as [RFC6343] have been written to help operators 376 understand observed problems with 6to4 deployments and provides 377 guidelines on how to improve it's performance. An operator may want 378 to provide local relays for 6to4 and/or Teredo to help improve the 379 protocol's performance for ambient traffic utilizing these IPv6 380 connectivity methods. Experiences such as those described in 381 [I-D.jjmb-v6ops-comcast-ipv6-experiences] show that local relays have 382 proved beneficial to 6to4 protocol performance. 384 Operators should also be aware of breakage cases for 6to4 if non- 385 RFC1918 addresses are used within CGN/NAT444 zones. Many off-the- 386 shelf CPEs and operating systems may turn on 6to4 without a valid 387 return path to the originating (local) host. This particular use 388 case can occur if any space other than [RFC1918] is used, including 389 Shared Address Space [RFC6598] or space registered to another 390 organization (squat space). The operator can use 6to4-PMT 391 [I-D.kuarsingh-v6ops-6to4-provider-managed-tunnel] or attempt to 392 block 6to4 operation entirely by blocking the anycast ranges 393 associated with [RFC3068]. 395 4.2. Carrier Grade NAT (NAT444) 397 Carrier Grade NAT (CGN), specifically as deployed in a NAT444 398 scenario [I-D.ietf-behave-lsn-requirements], may prove beneficial for 399 those operators who offer Dual Stack services to subscriber endpoints 400 once they exhaust their pools of IPv4 addresses. CGNs, and address 401 sharing overall, are known to cause certain challenges for the IPv4 402 service [RFC6269][I-D.donley-nat444-impacts], but may be necessary 403 depending on how an operator has chosen to deal with IPv6 transition 404 and legacy IPv4 connectivity requirements. 406 In a network where IPv4 address availability is low, CGN/NAT444, may 407 provide continued access to IPv4 endpoints. Some of the advantages 408 of using CGN/NAT444 include the similarities in provisioning and 409 activation models. IPv4 hosts in a CGN/NAT444 deployment will likely 410 inherent the same addressing and management procedures as legacy 411 IPv4, globally addressed hosts (i.e. DHCPv6, DNSv4, TFTP, TR-069 412 etc). 414 4.3. 6RD 416 6RD [RFC5969] provides a way of offering IPv6 connectivity to 417 subscriber endpoints when native IPv6 addressing on the access 418 network is not yet possible. 6RD provides tunneled connectivity for 419 IPv6 over the existing IPv4 path. As the access edge is upgraded and 420 subscriber premise equipment is replaced, 6RD can be replace by 421 native IPv6 connectivity. 6RD can be delivered over top a CGN/NAT444 422 deployment, but this would cause all traffic to be subject to some 423 type of transition technology. 425 6RD may also be advantageous during the early transition while IPv6 426 traffic volumes are low. During this period, the operator can gain 427 experience with IPv6 on the core and improve their peering framework 428 to match those of the IPv4 service. 6RD scales by adding relays to 429 the operator's network. Another advantage for 6RD is that the 430 operator does not need a DHCPv6 address assignment infrastructure and 431 does not need to support IPv6 routing to the CPE to support a 432 delegated prefix (as it's derived from the IPv4 address and other 433 configuration parameters). 435 Client support is required for 6RD operation and may not be available 436 on deployed hardware. 6RD deployments may require the subscriber or 437 operator to replace the CPE. 6RD will also require parameter 438 configuration which can be powered by the operator through DHCPv4, 439 manually provisioned on the CPE or automatically through some other 440 means. Manual provisioning would likely limit deployment scale. 442 4.4. Native Dual Stack 444 Native Dual Stack is often referred to as the "gold standard" of IPv6 445 and IPv4 delivery. It is a method of service delivery that is 446 already used in many existing IPv6 deployments. Native Dual Stack 447 does, however, require that Native IPv6 be delivered through the 448 access network to the subscriber premise. This technology option is 449 desirable in many cases and can be used immediately if the access 450 network and subscriber premise equipment supports native IPv6. 452 An operator who runs out of IPv4 addresses to assign to subscribers 453 will not be able to provide traditional native Dual Stack 454 connectivity for new subscribers. In Dual Stack deployments where 455 sufficient IPv4 addresses are not available, CGN/NAT444 can be used 456 on the IPv4 path. 458 Delivering native Dual Stack would require the operator's core and 459 access network to support IPv6. Other systems like DHCP, DNS, and 460 diagnostic/management facilities need to be upgraded to support IPv6 461 as well. The upgrade of such systems may often be non-trivial and 462 costly. 464 4.5. DS-Lite 466 Dual-Stack Lite (DS-Lite, [RFC6333]) is based on a native IPv6 467 connection model where IPv4 services are supported. DS-Lite provides 468 tunneled connectivity for IPv4 over the IPv6 path between the 469 subscriber's network device and a provider managed gateway (AFTR). 471 DS-Lite can only be used where there is native IPv6 connection 472 between the AFTR and the CPE. This may mean that the technology's 473 use may not be viable during early transition if the core or access 474 network lacks IPv6 support. During the early transition period, a 475 significant amount of content and services may by IPv4-only. 476 Operators may be sensitive to this and may not want the newer IPv6 477 path to be the only bridge to IPv4 at that time given the potential 478 impact. The operator may also want to make sure that most of its 479 internal services and a significant about of external content is 480 available over IPv6 before deploying DS-Lite. The availability of 481 services on IPv6 would help lower the demand on the AFTRs. 483 By sharing IPv4 addresses among multiple endpoints, like CGN/NAT444, 484 DS-Lite can facilitate continued support of legacy IPv4 services even 485 after IPv4 address run out. There are some functional considerations 486 to take into account with DS-Lite, such as those described in 487 [I-D.donley-nat444-impacts] and in [I-D.ietf-softwire-dslite- 488 deployment]. 490 DS-Lite requires client support on the CPE to function. The ability 491 to utilize DS-Lite will be dependent on the operator providing DS- 492 Lite capable CPEs or retail availability of the supported client for 493 subscriber-acquired endpoints. 495 4.6. NAT64 497 NAT64 [RFC6146] provides the ability to connect IPv6-only connected 498 clients and hosts to IPv4 servers without any tunneling. NAT64 499 requires that the host and home network supports IPv6-only modes of 500 operation. Home networks do not commonly contain equipment that is 501 100% IPv6-capable. It is also not anticipated that common home 502 networks will be ready for IPv6-only operation for a number of years. 503 However, IPv6-only networking can be deployed by early adopters or 504 highly controlled networks [RFC6586]. 506 Viability of NAT64 will increase in wireline networks as consumer 507 equipment is replaced by IPv6 capable versions. There are incentives 508 for operators to move to IPv6-only operation, when feasible, which 509 includes the simplicity of a single stack access network. 511 5. IPv6 Transition Phases 513 The Phases described in this document are not provided as a rigid set 514 of steps, but are considered a guideline which should be analyzed by 515 operators planning their IPv6 transition. Operators may choose to 516 skip steps based on technological capabilities within their specific 517 networks, (residential/corporate, fixed/mobile), their business 518 development perspectives (which may affect the pace of migration 519 towards full IPv6), or a combination thereof. 521 The phases are based on the expectation that IPv6 traffic volume may 522 initially be low, and operator staff will gain experience with IPv6 523 over time. As traffic volumes of IPv6 increase, IPv4 traffic volumes 524 will decline (in percentage relative to IPv4), until IPv6 is the 525 dominant address family used. Operators may want to keep the traffic 526 flow for the dominant traffic class (IPv4 vs. IPv6) native to help 527 manage costs related to transition technologies. The cost of using 528 multiple technologies in succession to optimize each stage of the 529 transition should also be compared against the cost of changing and 530 upgrading subscriber connections. 532 Additional guidance and information on utilizing IPv6 transition 533 mechanisms can be found in [RFC6180]. Also, guidance on incremental 534 CGN for IPv6 transition can also be found in [RFC6264]. 536 5.1. Phase 0 - Foundation 538 5.1.1. Phase 0 - Foundation: Training 540 Training is one of the most important steps in preparing an 541 organization to support IPv6. Most people have little experience 542 with IPv6, and many do not even have a solid grounding in IPv4. The 543 implementation of IPv6 will likely produce many challenges due to 544 immature code on hardware, and the evolution of many applications and 545 systems to support IPv6. To properly deal with these impending or 546 current challenges, organizations must train their staff on IPv6. 548 Training should also be provided within reasonable timelines from the 549 actual IPv6 deployment. This means the operator needs to plan in 550 advance as it trains the various parts of its organization. New 551 Technology and Engineering staff often receive little training 552 because of their depth of knowledge, but must at least be provided 553 opportunities to read documentation, architectural white papers, and 554 RFCs. Operations personnel who support the network and other systems 555 need to be trained closer to the deployment timeframes, so they 556 immediately use their new-found knowledge before forgetting. 558 Subscriber support staff would require much more basic but large 559 scale training since many organizations have massive call centers to 560 support the subscriber base. Tailored training will also be required 561 for marketing and sales staff to help them understand IPv6 and build 562 it into the product development and sales process. 564 5.1.2. Phase 0 - Foundation: Routing 566 The network infrastructure will need to be in place to support IPv6. 567 This includes the routed infrastructure along with addressing 568 principles, routing principles, peering policy and related network 569 functions. Since IPv6 is quite different from IPv4 in several ways 570 including the number of addresses which are made available, careful 571 attention to a scalable and manageable architecture needs to be made. 572 One such change is the notion of a delegated prefix, which deviates 573 from the common single address phenomenon in IPv4-only deployments. 574 Deploying prefixes per CPE can load the routing tables and require a 575 routing protocol or route gleaning to manage connectivity to the 576 subscriber's network. Delegating prefixes can be of specific 577 importance in access network environments where downstream subscriber 578 often move between access nodes, raising the concern of frequent 579 renumbering and/or managing movement of routed prefixes within the 580 network (common in cable based networks). 582 5.1.3. Phase 0 - Foundation: Network Policy and Security 584 Many, but not all, security policies will map easily from IPv4 to 585 IPv6. Some new policies may be required for issues specific to IPv6 586 operation. This document does not highlight these specific issues, 587 but raises the awareness they are of consideration and should be 588 addressed when delivering IPv6 services. Other IETF documents such 589 as [RFC4942], [RFC6092], and [RFC6169] are excellent resources. 591 5.1.4. Phase 0 - Foundation: Transition Architecture 593 The operators should plan out their transition architecture in 594 advance (with room for flexibility) to help optimize how they will 595 build out and scale their networks. Should the operator consider 596 multiple technologies like CGN/NAT444, DS-Lite, NAT64 and 6RD, they 597 may want to plan out where network resident equipment may be located 598 and potentially choose locations which can be used for all functional 599 roles (i.e. placement of NAT44 translator, AFTR, NAT64 gateway and 600 6RD relays). Although these functions are not inherently connected, 601 additional management, diagnostic and monitoring functions can be 602 deployed along side the transition hardware without the need to 603 distribute these to an excessive or divergent number of locations. 605 This approach may also prove beneficial if traffic patterns change 606 rapidly in the future as the operators may need to evolve their 607 transition infrastructure faster than originally anticipated. Once 608 such example may be the movement from a CGN/NAT44 model (dual stack) 609 to DS-Lite. Since both traffic sets require a translation function 610 (NAT44), synchronized pool management, routing and management system 611 positioning can allow rapid movement (notwithstanding the 612 technological means to re-provision the subscriber). 614 Operators should inform their vendors of what technologies they plan 615 to support over the course of the transition to make sure the 616 equipment is suited to support those modes of operation. This is 617 important for both network gear and subscriber premise equipment. 619 The operator should also plan their overall strategy to meet the 620 target needs of an IPv6-only deployment. As traffic moves to IPv6, 621 the benefits of only a single stack on the access network may 622 eventually justify the removal of IPv4 for simplicity. Planning for 623 this eventual model, no matter how far off this may be, will help the 624 operator embrace this end state when needed. 626 5.1.5. Phase 0- Foundation: Tools and Management 628 The operator should thoroughly analyze all provisioning and 629 management systems to develop requirements for each phase. This will 630 include concepts related to the 128-bit IPv6 address, the notation of 631 an assigned IPv6 prefix (Prefix Delegation) and the ability to detect 632 either or both address families when determining if a subscriber has 633 full Internet service. 635 If an operator stores usage information, this would need to be 636 aggregated to include both the IPv4 and IPv6 as both address families 637 are assigned to the same subscriber. Tools that verify connectivity 638 may need to query the IPv4 and IPv6 addresses. 640 5.2. Phase 1 - Tunneled IPv6 642 Tunneled access to IPv6 can be regarded as an early stage transition 643 option by operators. Many network operators can deploy native IPv6 644 from the access edge to the peering edge fairly quickly but may not 645 be able to offer IPv6 natively to the subscriber edge device. During 646 this period of time, tunneled access to IPv6 is a viable alternative 647 to native IPv6. It is also possible that operators may be rolling 648 out IPv6 natively to the subscriber edge but the time involved may be 649 long due to logistics and other factors. Even while carefully 650 rolling out native IPv6, operators can deploy relays for automatic 651 tunneling technologies like 6to4 and Teredo. Where native IPv6 to 652 the access edge is a longer-term project, operators can consider 6RD 653 [RFC5969] as an option to offer in-home IPv6 access. Note that 6to4 654 and Teredo have different address selection behaviors than 6RD 655 [RFC3484]. Additional guidelines on deploying and supporting 6to4 656 can be found in [RFC6343]. 658 The operator can deploy 6RD relays into the network and scale them as 659 needed to meet the early subscriber needs of IPv6. Since 6RD 660 requires the upgrade or replacement of CPE devices, the operator may 661 want to ensure that the CPE devices support not just 6RD but native 662 Dual Stack and other tunneling technologies if possible such as DS- 663 Lite [I-D.ietf-v6ops-6204bis]. 6RD clients are becoming available in 664 some retail channel products and within the OEM market. Retail 665 availability of 6RD is important since not all operators control or 666 have influence over what equipment is deployed in the consumer home 667 network. The operator can support 6RD access with unmanaged devices 668 using DHCPv4 option 212 (OPTION_6RD) [RFC5969]. 670 +--------+ ----- 671 | | / \ 672 Encap IPv6 Flow | 6RD | | IPv6 | 673 - - -> | BR | <- > | Net | 674 +---------+ / | | \ / 675 | | / +--------+ ----- 676 | 6RD + <----- ----- 677 | | / \ 678 | Client | IPv4 Flow | IPv4 | 679 | + < - - - - - - - - - - - - - - -> | Net | 680 | | \ / 681 +---------+ ----- 683 Figure 1: 6RD Basic Model 685 6RD used as an initial transition technology also provides the added 686 benefit of a deterministic IPv6 prefix based on the IPv4 assigned 687 address. Many operational tools are available or have been built to 688 identify what IPv4 (often dynamic) address was assigned to a 689 subscriber CPE. So, a simple tool and/or method can be built to help 690 identify the IPv6 prefix using the knowledge of the assigned IPv4 691 address. 693 An operator may choose to not offer internal services over IPv6 if 694 tunneled access to IPv6 is used since some services generate a large 695 amount of traffic. Such traffic may include Video content like IPTV. 696 By limiting how much traffic is delivered over the 6RD connection (if 697 possible), the operator can avoid costly and complex scaling of the 698 relay infrastructure. 700 5.2.1. 6RD Deployment Considerations 702 Deploying 6RD can greatly speed up an operator's ability to support 703 IPv6 to the subscriber network if native IPv6 connectivity cannot be 704 supplied. The speed at which 6RD can be deployed is highlighted in 705 [RFC5569]. 707 The first core consideration is deployment models. 6RD requires the 708 CPE (6RD client) to send traffic to a 6RD relay. These relays can 709 share a common anycast address, or can use unique addresses. Using 710 an anycast model, the operator can deploy all the 6RD relays using 711 the same IPv4 interior service address. As the load increases on the 712 deployed relays, the operator can deploy more relays into the 713 network. The one drawback is that it may be difficult to manage the 714 traffic volume among additional relays, since all 6RD traffic will 715 find the nearest (in terms of IGP cost) relay. Use of multiple relay 716 addresses can help provide more control but has the disadvantage of 717 being more complex to provision. Subsets of CPEs across the network 718 will require and contain different relay information. An alternative 719 approach is to use a hybrid model using multiple anycast service IP 720 Addresses for clusters of 6RD relays, should the operator anticipate 721 massive scaling of the environment. Thus, the operator has multiple 722 vectors by which to scale the service. 724 +--------+ 725 | | 726 IPv4 Addr.X | 6RD | 727 - - - > | BR | 728 +-----------+ / | | 729 | Client A | <- - - +--------+ 730 +-----------+ 731 Separate IPv4 Service Addresses 732 +-----------+ 733 | Client B | < - - +--------+ 734 +-----------+ \ | | 735 - - - > | 6RD | 736 IPv4 Addr.Y | BR | 737 | | 738 +--------+ 740 Figure 2: 6RD Multiple IPv4 Service Address Model 742 +--------+ 743 | | 744 IPv4 Addr.X | 6RD | 745 - - - > | BR | 746 +-----------+ / | | 747 | Client A |- - - - +--------+ 748 +-----------+ 749 Common (Anycast) IPv4 Service Addresses 750 +-----------+ 751 | Client B | - - - +--------+ 752 +-----------+ \ | | 753 - - - > | 6RD | 754 IPv4 Addr.X | BR | 755 | | 756 +--------+ 758 Figure 3: 6RD Anycast IPv4 Service Address Model 760 Provisioning of the 6RD endpoints is affected by the deployment model 761 chosen (i.e. anycast vs. specific service IP Addresses). Using 762 multiple IP Addresses may require more planning and management, as 763 subscriber equipment will have different sets of data to be 764 provisioned into the devices. The operator may use DHCPv4, manual 765 provisioning or other mechanisms to provide parameters to subscriber 766 equipment. 768 If the operator manages the CPE, support personnel will need tools 769 able to report the status of the 6RD tunnel. Usage information can 770 be counted on the operator edge, but if it requires source/ 771 destination flow details, data must be collected after the 6RD relay 772 (IPv6 side of connection). 774 6RD [RFC5969], as any tunneling option, is subject to a reduced MTU 775 so operators need to plan to manage this environment. 777 +---------+ IPv4 Encapsulation +------------+ 778 | +- - - - - - - - - - - + | 779 | 6RD +----------------------+ 6RD +--------- 780 | | IPv6 Packet | Relay | IPv6 Packet 781 | Client +----------------------+ +--------- 782 | +- - - - - - - - - - - + | ^ 783 +---------+ ^ +------------+ | 784 | | 785 | | 786 IPv4 IP (Tools/Mgmt) IPv6 Flow Analysis 788 Figure 4: 6RD Tools and Flow Management 790 5.3. Phase 2: Native Dual Stack 792 Either as a follow-up phase to "Tunneled IPv6" or as an initial step, 793 the operator may deploy native IPv6 down to the CPEs. This phase 794 would then allow for both IPv6 and IPv4 to be natively accessed by 795 the subscriber home network without translation or tunneling. The 796 native Dual Stack phase can be rolled out across the network while 797 the tunneled IPv6 service remains operational, if used. As areas 798 begin to support native IPv6, subscriber home equipment will 799 generally prefer using the IPv6 addresses derived from the delegated 800 IPv6 prefix versus tunneling options such as 6to4 and Teredo as 801 defined in [RFC3484]. Specific care is needed when moving to native 802 Dual Stack from 6RD as documented in 803 [I-D.townsley-v6ops-6rd-sunsetting]. 805 Native Dual Stack is the best option at this point in the transition, 806 and should be sought as soon as possible. During this phase, the 807 operator can confidently move both internal and external services to 808 IPv6. Since there are no translation devices needed for this mode of 809 operation, it transports both protocols (IPv6 and IPv4) efficiently 810 within the network. 812 5.3.1. Native Dual Stack Deployment Considerations 814 Native Dual Stack is a very desirable option for the IPv6 transition, 815 if feasible. The operator must enable IPv6 on the network core and 816 peering edge before they attempt to turn on native IPv6 services. 817 Additionally, provisioning and support systems such as DHCPv6, DNS 818 and other functions that support the subscriber's IPv6 Internet 819 connection need to be in place. 821 The operator must treat IPv6 connectivity with the same operational 822 importance as IPv4. A poor IPv6 service may be worse than not 823 offering an IPv6 service at all as it will negatively impact the 824 subscriber's Internet experience. This may cause users or support 825 personnel to disable IPv6, limiting the subscriber from the benefits 826 of IPv6 connectivity as the network performance improves. New code 827 and IPv6 functionality may cause instability at first. The operator 828 will need to monitor, troubleshoot and resolve issues promptly. 830 Prefix assignment and routing are new for common residential 831 services. Prefix assignment is straightforward (DHCPv6 using 832 IA_PDs), but installation and propagation of routing information for 833 the prefix, especially during access layer instability, is often 834 poorly understood. The operator should develop processes for 835 renumbering subscribers who move to new access nodes. 837 Operators need to keep track of both the dynamically assigned IPv4 838 address along with the IPv6 address and prefix. Any additional 839 dynamic elements, such as auto-generated host names, need to be 840 considered and planned for. 842 5.4. Intermediate Phase for CGN 844 Acquiring more IPv4 addresses is already challenging, if not 845 impossible; therefore address sharing may be required on the IPv4 846 path. The operator may have a preference to move directly to a 847 transition technology such as DS-Lite [RFC6333] or may choose CGN/ 848 NAT444 to facilitate IPv4 connections. CGN/NAT444 requires IPv4 849 addressing between the subscriber premise equipment and the 850 operator's translator which may be facilitated by shared address 851 [RFC6598], private address [RFC1918] or other address space. CGN/ 852 NAT444 should be used cautiously if used simultaneously with 6RD for 853 a common set of subscribers. Operators should be aware that if CGN/ 854 NAT444 is used in such manner, subscriber all traffic must traverse 855 some type of operator service node (relay and translator). Also, 856 care should be taken so as not to run 6RD through a DS-Lite tunnel or 857 vice versa. 859 +--------+ ----- 860 | | / \ 861 IPv4 Flow | CGN | | | 862 - - -> + + < -> | | 863 +---------+ / | | | | 864 | CPE | <- - - / +--------+ | IPv4 | 865 |---------+ | Net | 866 | | 867 +---------+ IPv4 Flow | | 868 | CPE | <- - - - - - - - - - - - - - - > | | 869 |---------+ \ / 870 ----- 872 Figure 5: Overlay CGN Deployment 874 In the case of native Dual Stack, CGN/NAT444 can be used to assist in 875 extending connectivity for the IPv4 path while the IPv6 path remains 876 native. For endpoints operating in a IPv6+CGN/NAT444 model, the 877 native IPv6 path is available for higher quality connectivity, 878 helping host operation over the network. At the same time, the CGN 879 path may offer a less than optimal performance. These points are 880 also true for DS-Lite. 882 +--------+ ----- 883 | | / \ 884 IPv4 Flow | CGN | | IPv4 | 885 - - -> + + < -> | Net | 886 +---------+ / | | \ / 887 | | <- - - / +--------+ ------- 888 | Dual | 889 | Stack | ----- 890 | CPE | IPv6 Flow / IPv6 \ 891 | | <- - - - - - - - - - - - - - - > | Net | 892 |---------+ \ / 893 ----- 895 Figure 6: Dual Stack with CGN 897 CGN/NAT444 deployments may make use of a number of address options, 898 which include [RFC1918] or Shared Address Space [RFC6598]. It is 899 also possible that operators may use part of their own RIR assigned 900 address space for CGN zone addressing if [RFC1918] addresses pose 901 technical challenges in their network. It is not recommended that 902 operators use 'squat space', as it may pose additional challenges 903 with filtering and policy control [RFC6598]. 905 5.4.1. CGN Deployment Considerations 907 CGN is often considered undesirable by operators but required in many 908 cases. An operator who needs to deploy CGN capabilities should 909 consider the impacts of the function to the network. CGN is often 910 deployed in addition to running IPv4 services and should not 911 negatively impact the already working Native IPv4 service. CGNs will 912 be needed at low scale at first and grown to meet the demands based 913 on traffic and connection dynamics of the subscriber, content and 914 network peers. 916 The operator may want to deploy CGNs more centrally at first and then 917 scale the system as needed. This approach can help conserve costs of 918 the system limiting the deploy based and scaling it based on actual 919 traffic demand. The operator should use a deployment model and 920 architecture which allows the system to scale as needed. 922 +--------+ ----- 923 | | / \ 924 | CGN | | | 925 - - -> + + < -> | | 926 +---------+ / | | | | 927 | CPE | <- - - / +--------+ | IPv4 | 928 | | ^ | | 929 |---------+ | | Net | 930 +--------+ Centralized | | 931 +---------+ | | CGN | | 932 | | | CGN | | | 933 | CPE | <- > + + <- - - - - - - > | | 934 |---------+ | | \ / 935 +--------+ ----- 936 ^ 937 | 938 Distributed CGN 940 Figure 7: CGN Deployment: Centralized vs. Distributed 942 The operator may be required to log translation information 943 [I-D.ietf-behave-lsn-requirements]. This logging may require 944 significant investment in external systems which ingest, aggregate 945 and report on such information [I-D.donley-behave-deterministic-cgn]. 947 Since CGN has noticeable impacts on certain applications [I-D.donley- 948 nat444-impacts], operators may deploy CGN only for those subscribers 949 who may be less affected by CGN (if possible). 951 5.5. Phase 3 - IPv6-Only 953 Once Native IPv6 is widely deployed in the network and well-supported 954 by tools, staff, and processes, an operator may consider supporting 955 only IPv6 to all or some subscriber endpoints. During this final 956 phase, IPv4 connectivity may or may not need to be supported, 957 depending on the conditions of the network and subscriber demand. If 958 legacy IPv4 connectivity is still demanded (e.g. for older nodes), 959 DS-Lite [RFC6333] may be used to tunnel the traffic. If IPv4 960 connectivity is not required, but access to legacy IPv4 content is, 961 then NAT64 [RFC6144][RFC6146] can be used. 963 DS-Lite allows continued access for the IPv4 subscriber base using 964 address sharing for IPv4 Internet connectivity, but with only a 965 single layer of translation, compared to CGN/NAT444. This mode of 966 operation also removes the need to directly supply subscriber 967 endpoints with an IPv4 address, potentially simplifying the 968 connectivity to the customer (single address family) and supporting 969 IPv6 only addressing to the CPE. 971 The operator can also move Dual Stack endpoints to DS-Lite 972 retroactively to help optimize the IPv4 address sharing deployment by 973 removing the IPv4 address assignment and routing component. To 974 minimize traffic needing translation, the operator should have 975 already moved most content to IPv6 before the IPv6-only phase is 976 implemented. 977 +--------+ ----- 978 | | / \ 979 Encap IPv4 Flow | AFTR | | IPv4 | 980 -------+ +---+ Net | 981 +---------+ / | | \ / 982 | | / +--------+ ----- 983 | DS-Lite +------- ----- 984 | | / \ 985 | Client | IPv6 Flow | IPv6 | 986 | +-------------------------------| Net | 987 | | \ / 988 +---------+ ----- 990 Figure 8: DS-Lite Basic Model 992 If the operator had previously decided to enable a CGN/NAT444 993 deployment, it may be able to co-locate the AFTR and CGN/NAT444 994 processing functions within a common network location to simplify 995 capacity management and the engineering of flows. This case may be 996 evident in a later transition stages when an operator chooses to 997 optimize its network and IPv6-only operation is feasible. 999 5.5.1. DS-Lite Deployment Considerations 1001 The same deployment considerations associated with Native IPv6 1002 deployments apply to DS-Lite and NAT64. IPv4 will now be dependent 1003 on IPv6 service quality, so the IPv6 network and services must be 1004 running well to ensure a quality experience for the end subscriber. 1005 Tools and processes will be needed to manage the encapsulated IPv4 1006 service. If flow analysis is required for IPv4 traffic, this may be 1007 enabled at a point beyond the AFTR (after de-capsulation) or DS-Lite 1008 [RFC6333] aware equipment is used to process traffic midstream. 1010 +---------+ IPv6 Encapsulation +------------+ 1011 | + - - - - - - - - - - -+ | 1012 | AFTR +----------------------+ AFTR +--------- 1013 | | IPv4 Packet | | IPv4 Packet 1014 | Client +----------------------+ +--------- 1015 | + - - - - - - - - - - -+ | ^ 1016 +---------+ ^ ^ +------------+ | 1017 | | | 1018 | | | 1019 IPv6 IP (Tools/Mgmt) | IPv4 Packet Flow Analysis 1020 | 1021 Midstream IPv4 Packet Flow Analysis (Encapsulation Aware) 1023 Figure 9: DS-Lite Tools and Flow Analysis 1025 DS-Lite [RFC6333] also requires client support on the subscribers 1026 premise device. The operator must clearly articulate to vendors 1027 which technologies will be used at which points, how they interact 1028 with each other at the CPE, and how they will be provisioned. As an 1029 example, an operator may use 6RD in the outset of the transition, 1030 then move to Native Dual Stack followed by DS-Lite. 1032 DS-Lite [RFC6333], as any tunneling option, is subject to a reduced 1033 MTU so operators need to plan to manage this environment. Additional 1034 considerations for DS-Lite deployments can be found in [I-D.ietf- 1035 softwire-dslite-deployment]. 1037 5.5.2. NAT64 Deployment Considerations 1039 The deployment of NAT64 assumes the network assigns an IPv6 address 1040 to a network endpoint that is translated to an IPv4 address to 1041 provide connectivity to IPv4 Internet services and content. 1042 Experiments such as the one described in [RFC6586] highlight issues 1043 related to IPv6-only deployments due to legacy IPv4 APIs and IPv4 1044 literals. Many of these issues will be resolved by the eventual 1045 removal this undesired legacy behavior. Operational deployment 1046 models, considerations and experiences related to NAT64 have been 1047 documented in [I-D.chen-v6ops-nat64-experience]. 1049 +--------+ ----- 1050 | | / \ 1051 IPv6 Flow | NAT64 | | IPv4 | 1052 -------+ DNS64 +---+ Net | 1053 +---------+ / | | \ / 1054 | | / +--------+ ----- 1055 | IPv6 +------- ----- 1056 | | / \ 1057 | Only | IPv6 Flow | IPv6 | 1058 | +-------------------------------| Net | 1059 | | \ / 1060 +---------+ ----- 1062 Figure 10: NAT64/DNS64 Basic Model 1064 To navigate around some of the limitations of NAT64 when dealing with 1065 legacy IPv4 applications, the operator may choose to implement 1066 464XLAT [I-D.ietf-v6ops-464xlat] if possible. As support for IPv6 on 1067 subscriber equipment and content increases, the efficiency of NAT64 1068 increases by reducing the need to translate traffic. The NAT64 1069 deployment would see an overall decline in usage as more traffic is 1070 promoted to IPv6-to-IPv6 native communication. NAT64 may play an 1071 important part of an operator's late stage transition, as it removes 1072 the need to support IPv4 on the access network and provides a solid 1073 go-forward networking model. 1075 6. IANA Considerations 1077 No IANA considerations are defined at this time. 1079 7. Security Considerations 1081 Operators should review the documentation related to the technologies 1082 selected for IPv6 transition. In those reviews, operators should 1083 understand what security considerations are applicable to the chosen 1084 technologies. As an example, [RFC6169] should be reviewed to 1085 understand security considerations around tunnelling technologies. 1087 8. Acknowledgements 1089 Special thanks to Wes George, Chris Donley, Christian Jacquenet and 1090 John Brzozowski for their extensive review and comments. 1092 Thanks to the following people for their textual contributions, 1093 guidance and comments: Jason Weil, Gang Chen, Nik Lavorato, John 1094 Cianfarani, Chris Donley, Tina TSOU, Fred Baker and Randy Bush. 1096 9. References 1098 9.1. Normative References 1100 [RFC6180] Arkko, J. and F. Baker, "Guidelines for Using IPv6 1101 Transition Mechanisms during IPv6 Deployment", RFC 6180, 1102 May 2011. 1104 9.2. Informative References 1106 [I-D.chen-v6ops-nat64-experience] 1107 Chen, G., Cao, Z., Byrne, C., and Q. Niu, "NAT64 1108 Operational Experiences", 1109 draft-chen-v6ops-nat64-experience-01 (work in progress), 1110 March 2012. 1112 [I-D.donley-behave-deterministic-cgn] 1113 Donley, C., Grundemann, C., Sarawat, V., and K. 1114 Sundaresan, "Deterministic Address Mapping to Reduce 1115 Logging in Carrier Grade NAT Deployments", 1116 draft-donley-behave-deterministic-cgn-02 (work in 1117 progress), March 2012. 1119 [I-D.donley-nat444-impacts] 1120 Donley, C., Howard, L., Kuarsingh, V., Berg, J., and U. 1121 Colorado, "Assessing the Impact of Carrier-Grade NAT on 1122 Network Applications", draft-donley-nat444-impacts-04 1123 (work in progress), May 2012. 1125 [I-D.ieft-softwire-dslite-deployment] 1126 Lee, Y., Maglione, R., Williams, C., and C. Jacquenet, 1127 "Deployment Considerations for Dual-Stack Lite", 1128 draft-ieft-softwire-dslite-deployment-00 (work in 1129 progress), September 2011. 1131 [I-D.ietf-behave-lsn-requirements] 1132 Perreault, S., Yamagata, I., Miyakawa, S., Nakagawa, A., 1133 and H. Ashida, "Common requirements for Carrier Grade NATs 1134 (CGNs)", draft-ietf-behave-lsn-requirements-06 (work in 1135 progress), May 2012. 1137 [I-D.ietf-v6ops-464xlat] 1138 Mawatari, M., Kawashima, M., and C. Byrne, "464XLAT: 1139 Combination of Stateful and Stateless Translation", 1140 draft-ietf-v6ops-464xlat-03 (work in progress), May 2012. 1142 [I-D.ietf-v6ops-6204bis] 1143 Singh, H., Beebee, W., Donley, C., and B. Stark, "Basic 1144 Requirements for IPv6 Customer Edge Routers", 1145 draft-ietf-v6ops-6204bis-09 (work in progress), May 2012. 1147 [I-D.jjmb-v6ops-comcast-ipv6-experiences] 1148 Brzozowski, J. and C. Griffiths, "Comcast IPv6 Trial/ 1149 Deployment Experiences", 1150 draft-jjmb-v6ops-comcast-ipv6-experiences-02 (work in 1151 progress), October 2011. 1153 [I-D.kuarsingh-v6ops-6to4-provider-managed-tunnel] 1154 Kuarsingh, V., Lee, Y., and O. Vautrin, "6to4 Provider 1155 Managed Tunnels", 1156 draft-kuarsingh-v6ops-6to4-provider-managed-tunnel-06 1157 (work in progress), May 2012. 1159 [I-D.townsley-v6ops-6rd-sunsetting] 1160 Cassen, A. and M. Townsley, "6rd Sunsetting", 1161 draft-townsley-v6ops-6rd-sunsetting-00 (work in progress), 1162 November 2011. 1164 [RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and 1165 E. Lear, "Address Allocation for Private Internets", 1166 BCP 5, RFC 1918, February 1996. 1168 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1169 (IPv6) Specification", RFC 2460, December 1998. 1171 [RFC3056] Carpenter, B. and K. Moore, "Connection of IPv6 Domains 1172 via IPv4 Clouds", RFC 3056, February 2001. 1174 [RFC3068] Huitema, C., "An Anycast Prefix for 6to4 Relay Routers", 1175 RFC 3068, June 2001. 1177 [RFC3484] Draves, R., "Default Address Selection for Internet 1178 Protocol version 6 (IPv6)", RFC 3484, February 2003. 1180 [RFC4380] Huitema, C., "Teredo: Tunneling IPv6 over UDP through 1181 Network Address Translations (NATs)", RFC 4380, 1182 February 2006. 1184 [RFC4942] Davies, E., Krishnan, S., and P. Savola, "IPv6 Transition/ 1185 Co-existence Security Considerations", RFC 4942, 1186 September 2007. 1188 [RFC5569] Despres, R., "IPv6 Rapid Deployment on IPv4 1189 Infrastructures (6rd)", RFC 5569, January 2010. 1191 [RFC5969] Townsley, W. and O. Troan, "IPv6 Rapid Deployment on IPv4 1192 Infrastructures (6rd) -- Protocol Specification", 1193 RFC 5969, August 2010. 1195 [RFC6092] Woodyatt, J., "Recommended Simple Security Capabilities in 1196 Customer Premises Equipment (CPE) for Providing 1197 Residential IPv6 Internet Service", RFC 6092, 1198 January 2011. 1200 [RFC6144] Baker, F., Li, X., Bao, C., and K. Yin, "Framework for 1201 IPv4/IPv6 Translation", RFC 6144, April 2011. 1203 [RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful 1204 NAT64: Network Address and Protocol Translation from IPv6 1205 Clients to IPv4 Servers", RFC 6146, April 2011. 1207 [RFC6169] Krishnan, S., Thaler, D., and J. Hoagland, "Security 1208 Concerns with IP Tunneling", RFC 6169, April 2011. 1210 [RFC6264] Jiang, S., Guo, D., and B. Carpenter, "An Incremental 1211 Carrier-Grade NAT (CGN) for IPv6 Transition", RFC 6264, 1212 June 2011. 1214 [RFC6269] Ford, M., Boucadair, M., Durand, A., Levis, P., and P. 1215 Roberts, "Issues with IP Address Sharing", RFC 6269, 1216 June 2011. 1218 [RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual- 1219 Stack Lite Broadband Deployments Following IPv4 1220 Exhaustion", RFC 6333, August 2011. 1222 [RFC6343] Carpenter, B., "Advisory Guidelines for 6to4 Deployment", 1223 RFC 6343, August 2011. 1225 [RFC6540] George, W., Donley, C., Liljenstolpe, C., and L. Howard, 1226 "IPv6 Support Required for All IP-Capable Nodes", BCP 177, 1227 RFC 6540, April 2012. 1229 [RFC6586] Arkko, J. and A. Keranen, "Experiences from an IPv6-Only 1230 Network", RFC 6586, April 2012. 1232 [RFC6598] Weil, J., Kuarsingh, V., Donley, C., Liljenstolpe, C., and 1233 M. Azinger, "IANA-Reserved IPv4 Prefix for Shared Address 1234 Space", BCP 153, RFC 6598, April 2012. 1236 Authors' Addresses 1238 Victor Kuarsingh (editor) 1239 Rogers Communications 1240 8200 Dixie Road 1241 Brampton, Ontario L6T 0C1 1242 Canada 1244 Email: victor.kuarsingh@gmail.com 1245 URI: http://www.rogers.com 1247 Lee Howard 1248 Time Warner Cable 1249 13820 Sunrise Valley Drive 1250 Herndon, VA 20171 1251 US 1253 Email: lee.howard@twcable.com 1254 URI: http://www.timewarnercable.com