Internet Engineering Task Force S. Matsushima Internet-Draft Softbank Telecom Intended status: Informational Y. Yamazaki Expires: September 30, 2011 Softbank Mobile C. Sun M. Yamanishi J. Jiao Softbank BB March 29, 2011 Use case and consideration experiences of IPv4 to IPv6 transition draft-matsushima-v6ops-transition-experience-02 Abstract Service Providers will apply their use case when conducting IPv6 transition and determine helpful solutions with the assistance of the IPv6 transition guideline document. More than one solution is possible, and decisions must be made from not only the technical point of view, but also from the economic point of view. This document describes the conclusions reached by one operator based on their considerations and their plans for IPv6 transition so as to assist others who may have similar circumstances. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on September 30, 2011. Copyright Notice Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Matsushima, et al. Expires September 30, 2011 [Page 1] Internet-Draft 4rd transition considerations experience March 2011 Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Transition overview and current status . . . . . . . . . . . . 3 3. Experience of IPv4-only Network and Assessment Approach . . . . 3 4. Considerations for IPv6-Only network . . . . . . . . . . . . . 4 5. Considerations for Mobile network . . . . . . . . . . . . . . . 5 6. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 5 7. Security considerations . . . . . . . . . . . . . . . . . . . . 6 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 9.1. Normative References . . . . . . . . . . . . . . . . . . . 6 9.2. Informative References . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Matsushima, et al. Expires September 30, 2011 [Page 2] Internet-Draft 4rd transition considerations experience March 2011 1. Introduction IPv4 to IPv6 transition solutions are becoming more converged. Given the variety of operators involved, various use-case scenarios exist and efforts are underway to clarify them. Since the first group addressing IPv6 transition are technically inclined, the economic analyses needed for creating business plans are often delayed. One key factor impacting the business plan is architecture. The solution will be considered and then adopted so as to implement the most efficient architecture for each operator. In other words, the Service Provider who wants to ensure long-term viability must place greater emphasis on the economic impact of IPv6 transition. The author expect that IETF has great interest in this approach given its engineering and standardization work. Moreover, sharing the considerations described in this document would be helpful to operators who are in similar circumstances. 2. Transition overview and current status Various transition use-cases have been published. [I-D.huang-v6ops-v4v6tran-bb-usecase] [I-D.lee-v6ops-tran-cable-usecase] [I-D.tsou-v6ops-mobile-transition-guide] [I-D.sunq-v6ops-ivi-sp] IPv6 transition guideline document [I-D.arkko-ipv6-transition-guidelines] presents four deployment models. As our ultimate goal is the IPv6 only network, our strategy to achieving it is: (1) provide IPv6 connectivity to the existing IPv4-Only network, (2) build new IPv6-Only network, (3) migrate our customers from the IPv4-Only network to the IPv6-Only network. Along with the guideline, we had studied the "Crossing IPv4 Islands" model in the guideline to realize (1), while performing (2) in parallel. Subsequently, we started studying the "IPv6-Only Core Network" model to achieve (3). Research into a deployment model for our mobile network is now in progress. 3. Experience of IPv4-only Network and Assessment Approach Our starting point is ensuring that the IPv4-Only network can provide IPv6 connectivity. Since our final goal is to build a IPv6-only network and migrate all customers to the network, we will not have to accommodate new customers beyond current capacity in the existing IPv4-only network. This means two things for the IPv4-only network; one, "minimized additional resources will provided to keep the network" and two, "there is less need to conserve IPv4 addresses in Matsushima, et al. Expires September 30, 2011 [Page 3] Internet-Draft 4rd transition considerations experience March 2011 the network". As the guideline document pointed out, many "IPv6 over IPv4 tunneling" solutions have already been developed. Our criterion for adopting the best solution involves not only technical pros/cons, but also the cost efficiency of providing IPv6 connectivity to all customers in the IPv4-only networks. When the total capital and operational expense of the system is represented as "Q", and the number of customers that can be served by the system as "T", the metric of cost efficiency, "S", is given by the following simple formula: S=Q/T We gathered the S values of all candidate products and solutions, and decided to adopt the solution that had the lowest S value. Ignoring the price difference between the products, the stateful solutions have S values that are significantly different from those of the stateless solutions. In stateful solutions, T is the total number of system capable sessions divided by the number of sessions per customer. In stateless solutions, on the other hand, T is the total amount of system bandwidth capacity divided by the bandwidth consumption per customer. From our experience, S(A) < S(B), that is, S(A) is always more efficient than S(B) (note S(A) is stateless, S(B) is stateful). We consequently adopt 6rd [RFC5969] for IPv4-only network. As the guideline document points out, it is not productive to implement an optimal IPv6 transition system as a temporary solution with goal of rich functionality. Many service providers hope that by allocating more resource they can increase network performance, bandwidth capacity, and the coverage of their network. In other words, we, as a service provider, want to minimize the resources allocated to such temporary solutions. 4. Considerations for IPv6-Only network Our considerations suggest that a stateless solution should be adopted for the IPv6-only network to minimize overall resource allocation and to allocate resources to the more productive areas. In one of IPv6-only network deployment scenario, routing and addressing lie outside our control except for our own prefix, which is assigned to the customers who connect to the network. It seems like relation of operators among wholesale and retail. In that network, it is difficult to avoid assigning well known and other operator owned IPv4 prefixes if the stateless solution uses the 32bit IPv4 address to IPv6 address mapping technique. The solution must meet the requirements of: (1) The routing path for IPv4 should match Matsushima, et al. Expires September 30, 2011 [Page 4] Internet-Draft 4rd transition considerations experience March 2011 the optimized IPv6 routing path, (2) It should be capable to share one IPv4 address among customers since the number of IPv4 addresses is insufficient, (3) It must be stateless. We will adopt the solution that satisfies these three requirements. According to [I-D.sun-intarea-4rd-applicability], there are significant characteristics in particular these three requirements are satisfied. It is noted that since some customers require a service which no address sharing, a non-address sharing solution is also needed, but this does not need to be the same as the address sharing solution. The guideline document describes that Dual-Stack-lite [I-D.ietf-softwire-dual-stack-lite] is recommended only as a transition solution on the way to the IPv6-only network. Compared to other deployment scenarios such as crossing IPv4 island and IPv6-only deployment, there are several candidate solutions for each deployment model but only one solution for the scenario. It is noted that the solutions not mentioned in the guideline are discussed in [I-D.dec-stateless-4v6], which adopt 4rd [I-D.despres-intarea-4rd] and dIVI [I-D.xli-behave-divi]. 5. Considerations for Mobile network We believe that the requirements explained in the previous section should be applied to the mobile network as well. [TR23.975], has clarified the IPv6-only deployment model in the guideline as a IPv6 transition scenario. As [I-D.arkko-ipv6-only-experience] pointed out, the operators' policy of service quality assurance may require the solution of avoiding the IPv4 referral issue [I-D.ietf-behave-v4v6-bih] It is interesting that stateless address mapping techniques exist for both encapsulation/decapsulation and translation in the case of IPv4 crossing IPv6-only network model. This means that, the requirements listed in previous section could be achieved for the mobile network. 6. Conclusions One of most significant areas that remain to be investigated is the physical resources of our network. We also need to minimize the investments needed to secure the IP transition (i.e. the temporary solutions) because we believe that the ultimate goal of the transition must be the long-term viability of the Internet and also the provision of our services. To ensure that, our considerations yielded the conclusion that the stateless solution should be specified for all deployment models in the guideline document. It is recommended that IETF standardize on stateless solutions for not only Matsushima, et al. Expires September 30, 2011 [Page 5] Internet-Draft 4rd transition considerations experience March 2011 the IPv4-only network, but also both the IPv6-only network and Ipv6- only deployment models in the guideline. 7. Security considerations A stateless solution without the appropriate implementation and operation techniques would be vulnerable to denial of service attacks, routing loops, spoofing, and other such malicious acts. To eliminate these security vulnerabilities, a stateless solution, like 6rd, which is capable of validating consistency of IPv6 source address with IPv4 source address, can be used to avoid these vulnerabilities, based on its address mapping rule. If a stateless solution supports IPv4 address sharing, it must take into account the issues described in [I-D.ietf-intarea-shared-addressing-issues]. If an operator is concerned about the unnecessary bandwidth consumption created by unwanted packets from the outside, one recommended solution is to implement appropriate firewall protection for not only v4v6 transition solution, but also both native IPv4 and IPv6 networks. 8. Acknowledgements The authors would like to thank the guideline document of IPv6 transition [I-D.arkko-ipv6-transition-guidelines], which guides us through the transition way, and has motivated the authors to write this document. We also would like to thank Miwa Fujii for her helpful suggestions and supports to share our experience with many people. 9. References 9.1. Normative References [I-D.arkko-ipv6-transition-guidelines] Arkko, J. and F. Baker, "Guidelines for Using IPv6 Transition Mechanisms during IPv6 Deployment", draft-arkko-ipv6-transition-guidelines-14 (work in progress), December 2010. 9.2. Informative References [I-D.arkko-ipv6-only-experience] Arkko, J. and A. Keranen, "Experiences from an IPv6-Only Network", draft-arkko-ipv6-only-experience-02 (work in progress), October 2010. Matsushima, et al. Expires September 30, 2011 [Page 6] Internet-Draft 4rd transition considerations experience March 2011 [I-D.dec-stateless-4v6] Dec, W., "Stateless 4Via6 Address Sharing", draft-dec-stateless-4v6-01 (work in progress), March 2011. [I-D.despres-intarea-4rd] Despres, R., Matsushima, S., Murakami, T., and O. Troan, "IPv4 Residual Deployment across IPv6-Service networks (4rd) ISP-NAT's made optional", draft-despres-intarea-4rd-01 (work in progress), March 2011. [I-D.huang-v6ops-v4v6tran-bb-usecase] Huang, C., Li, X., and L. Hu, "Use Case For IPv6 Transition For a Large-Scale Broadband network", draft-huang-v6ops-v4v6tran-bb-usecase-01 (work in progress), October 2010. [I-D.ietf-behave-v4v6-bih] Huang, B., Deng, H., and T. Savolainen, "Dual Stack Hosts Using "Bump-in-the-Host" (BIH)", draft-ietf-behave-v4v6-bih-03 (work in progress), March 2011. [I-D.ietf-intarea-shared-addressing-issues] Ford, M., Boucadair, M., Durand, A., Levis, P., and P. Roberts, "Issues with IP Address Sharing", draft-ietf-intarea-shared-addressing-issues-05 (work in progress), March 2011. [I-D.ietf-softwire-dual-stack-lite] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual- Stack Lite Broadband Deployments Following IPv4 Exhaustion", draft-ietf-softwire-dual-stack-lite-07 (work in progress), March 2011. [I-D.lee-v6ops-tran-cable-usecase] Lee, Y. and V. Kuarsingh, "IPv6 Transition Cable Access Network Use Cases", draft-lee-v6ops-tran-cable-usecase-00 (work in progress), October 2010. [I-D.sun-intarea-4rd-applicability] Sun, C., Matsushima, S., and J. Jiao, "4rd Applicability Statement", draft-sun-intarea-4rd-applicability-01 (work in progress), March 2011. [I-D.sunq-v6ops-ivi-sp] Sun, Q., Xie, C., Li, X., Bao, C., and M. Feng, "Considerations for Stateless Translation (IVI/dIVI) in Matsushima, et al. Expires September 30, 2011 [Page 7] Internet-Draft 4rd transition considerations experience March 2011 Large SP Network", draft-sunq-v6ops-ivi-sp-02 (work in progress), March 2011. [I-D.tsou-v6ops-mobile-transition-guide] ZOU), T. and T. Taylor, "IPv6 Transition Guide For A Large Mobile Operator", draft-tsou-v6ops-mobile-transition-guide-00 (work in progress), October 2010. [I-D.xli-behave-divi] Li, X., Bao, C., and H. Zhang, "Address-sharing stateless double IVI", draft-xli-behave-divi-01 (work in progress), October 2009. [I-D.ymbk-aplusp] Bush, R., "The A+P Approach to the IPv4 Address Shortage", draft-ymbk-aplusp-09 (work in progress), February 2011. [RFC5565] Wu, J., Cui, Y., Metz, C., and E. Rosen, "Softwire Mesh Framework", RFC 5565, June 2009. [RFC5969] Townsley, W. and O. Troan, "IPv6 Rapid Deployment on IPv4 Infrastructures (6rd) -- Protocol Specification", RFC 5969, August 2010. [TR23.975] "3GPP, IPv6 migration guidelines", . Authors' Addresses Satoru Matsushima Softbank Telecom Tokyo Shiodome Building 1-9-1,Higashi-Shibashi,Minato-Ku Tokyo 105-7322 JAPAN Email: satoru.matsushima@tm.softbank.co.jp Matsushima, et al. Expires September 30, 2011 [Page 8] Internet-Draft 4rd transition considerations experience March 2011 Yuji Yamazaki Softbank Mobile Tokyo Shiodome Building 1-9-1,Higashi-Shibashi,Minato-Ku Tokyo 105-7322 JAPAN Email: yuyamaza@bb.softbank.co.jp Chunfa Sun Softbank BB Tokyo Shiodome Building 1-9-1,Higashi-Shibashi,Minato-Ku Tokyo 105-7322 JAPAN Email: c-sun@bb.softbank.co.jp Masato Yamanishi Softbank BB 611 Wilshire Blvd., Suite 400 Los Angeles, CA USA Email: myamanis@bb.softbank.co.jp Jie Jiao Softbank BB Tokyo Shiodome Building 1-9-1,Higashi-Shibashi,Minato-Ku Tokyo 105-7322 JAPAN Email: j-jiao@bb.softbank.co.jp Matsushima, et al. Expires September 30, 2011 [Page 9]