v6ops Q. Sun Internet-Draft C. Xie Intended status: Informational China Telecom Expires: November 7, 2011 J. Qin ZTE Q. Liu China Telecom D. Liu BII Group May 6, 2011 Rapid Transition of IPv4 contents to IPv6-accessible draft-sunq-v6ops-contents-transition-00 Abstract This document describes one deployment model of NAT64, aiming to rapidly increase the amount of contents which are IPv6 accessible for users from IPv6 Internet. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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. 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Expires November 7, 2011 [Page 2] Internet-Draft Contents Transition May 2011 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language . . . . . . . . . . . . . . . . . . . 3 2. Deployment Scenario . . . . . . . . . . . . . . . . . . . . . . 4 3. Overall procedure . . . . . . . . . . . . . . . . . . . . . . . 4 4. 5. Deployment Considerations . . . . . . . . . . . . . . . . . 5 4.1. Stateful Translation . . . . . . . . . . . . . . . . . . . 5 4.2. Addressing and mapping . . . . . . . . . . . . . . . . . . 5 4.3. DNS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4.4. Capacity . . . . . . . . . . . . . . . . . . . . . . . . . 5 4.5. Traffic Logging and User Management . . . . . . . . . . . . 5 4.6. ALG . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 8.1. Normative References . . . . . . . . . . . . . . . . . . . 6 8.2. Informative References . . . . . . . . . . . . . . . . . . 7 Appendix A. Deployment Example . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 Sun, et al. Expires November 7, 2011 [Page 3] Internet-Draft Contents Transition May 2011 1. Introduction The global IPv4 address depletion becomes a reality. Although the IPv4 to IPv6 transition is considered inevitable, deployments of IPv6 are still quite limited as this document is written. Facing the pressure of IPv4 address shortage, the operaters may like to provide services through IPv6 in some wayes. However, compared to the readiness of operaters' infrastructures, the IPv6 transition on the content provider and end user sides moves even more slowly. There have been statements from several popular content providers that they have turned on, or planned to turn on IPv6 soon, which do have a beneficial effect on encouraging end users to transit to IPv6. While given the operational cost and the risk to the continuity of service delivery, compared to the number of active IPv6 users currently, it is difficult to convince much more content providers (especially conservative ones and, the great many ones of small-to-medium size) to immediately enable IPv6 and make their publically-facing services accessible through IPv6 natively. On the other hand, from the users' perspective the IPv6 reachability of resources required for their daily lives is one of the foremost factors that they concern when making the decision on whether or not to access Internet using IPv6. It is a chicken or egg dilemma, but the two perspectives are interdependent. If the transition of one side passes the point of inflexion, the other side will be speeded up after. So, more efforts are needed to encourage the IPv6 adoption and reach the point. This document describes one deployment model of [I-D.ietf-behave-v6v4-xlate-stateful], aiming at rapidly increasing the amount of IPv6 reachable contents for users from IPv6 Internet. The contents can be still accessible through IPv4. While this must not be used as a long-term solution, and the native transition of contents should always be recommended. 1.1. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. Sun, et al. Expires November 7, 2011 [Page 4] Internet-Draft Contents Transition May 2011 2. Deployment Scenario +-----+ | DNS | +-----+ \ \ +----------------+ +--------------+ | IDC | +-------+ | IPv6 | | | --- | Xlate | --- | Internet | | +--------+ | +-------+ +--------------+ | | IPv4 | | | | Server | | +--------------+ | +--------+ | --------------- | IPv4 | | | | Internet | +----------------+ +--------------+ The NAT64 gateway is deployed between the IPv6 Internet and the IPv4 server. An IPv6 prefix is assigned to embed the IPv4 addresses of the server then form IPv6 addresses (per [RFC6052]) which are used for AAAA records adding. The route of the IPv6 prefix should be advertised by the NAT64 gateway to IPv6 Internet. Also, an IPv4 address pool is needed on the Xlate to translate IPv6 packets to IPv4. Private addresses (e.g. 10/8) may be used. 3. Overall procedure Before initiating a session, generally an IPv6 user will do a DNS lookup to get the AAAA records and learn the addresses of the host to be accessed. In this case, the IPv6 addresses learned through AAAA records are those translated from the IPv4 addresses of the server. In this deployment model, the NAT64 gateway will perform the translation from IPv6 to IPv4, and vice versa. The communication is initiated by the IPv6 side. When an IPv6 packet arrives, a lookup of the mapping table will take place to get the IPv4 address used for translation. If there is no one matched, a new entry will be created. 1:1 mapping is employed in the context of this deployment model, which would simplify the packet processing procedure.Then, the translated packet with private IPv4 address would be sent to the IPv4 server. Sun, et al. Expires November 7, 2011 [Page 5] Internet-Draft Contents Transition May 2011 4. 5. Deployment Considerations 4.1. Stateful Translation The translation functions are specified in [I-D.ietf-behave-v6v4-xlate-stateful], which allows clients from IPv6 Internet to contact IPv4 server in Data Center. 4.2. Addressing and mapping To save global IPv4 addresses which become scarce resources, private blocks, for instance 10.0.0.0/8 can be used by the NAT64 gateway for Stateful NAT64 operations. Since the scenario of server side is different from that of client side and considering the capacity of devices for the scale of traffic in the foreseeable future, we choose 1:1 address mapping (one IPv6 address mapped to one private IPv4 address). In this way, the problems introduced by address sharing could be avoided and the efficiency of NAT64 operations could be improved (Refer to Section 4.4 for capacity considerations). Note that Conflicts might happen when the same private address space is used for the interconnection of servers internally. (e.g., for Load Balancing) An IPv6 prefix is needed to represent the IPv4 servers, and the route of the prefix should be advertised to the IPv6 Internet. 4.3. DNS Correspondingly, the AAAA records are needed to serve the end users from IPv6 Internet. Two methods could be considered: deploying the DNS64 along with the NAT64 gateway to respond the queries from IPv6 Internet with dynamically formed AAAA records; manually adding AAAA records based on translated addresses into the authorized name servers, some auto-configuration tools may be used. ... 4.4. Capacity In theory, about 16 million sessions can be established simultaneously if for example the 10.0.0.0/8 block is used for 1:1 stateful NAT64 in the configured-lifetime. 4.5. Traffic Logging and User Management Traffic logging and user management is important. Since only 1:1 addressing mapping is used in this model, traffic logging system will Sun, et al. Expires November 7, 2011 [Page 6] Internet-Draft Contents Transition May 2011 be substaintially simplified to record IPv6 end-user address, translated IPv4 address, timestamp and lifetime. The traffic statistics can be used by content providers as a reference when setting out the timetable of native transition. 4.6. ALG Only limited ALGs need to be deployed in NAT64 gateway according to the services provided. 5. Acknowledgements TBD 6. IANA Considerations This document includes no request to IANA. 7. Security Considerations Some malicious attackers can send a large number of IPv6 packets with different forged source IPv6 addresses, to rapidly deplete the IPv4 address pool, which is a kind of DOS attack. 8. References 8.1. Normative References [I-D.ietf-behave-v6v4-xlate-stateful] Bagnulo, M., Matthews, P., and I. Beijnum, "Stateful NAT64: Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers", draft-ietf-behave-v6v4-xlate-stateful-12 (work in progress), July 2010. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X. Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052, October 2010. Sun, et al. Expires November 7, 2011 [Page 7] Internet-Draft Contents Transition May 2011 8.2. Informative References [RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, June 1999. Appendix A. Deployment Example We have deployed 1:1 addressing mapping NAT64 prototype in Hunan Province. Currently, there are three content providers covered by our deployment. Refer to www.2118.com.cn, www.5460.net and www.118326.com. ... Authors' Addresses Qiong Sun China Telecom Room 708 No.118, Xizhimenneidajie Beijing, Xicheng 100035 P.R.China Phone: 86 10 58552936 Email: sunqiong@ctbri.com.cn Chongfeng Xie China Telecom Room 708 No.118, Xizhimenneidajie Beijing, Xicheng 100035 P.R.China Phone: 86 10 58552116 Email: xiechf@ctbri.com.cn Jacni Qin ZTE Shanghai, China Phone: +86 1391 861 9913 Email: jacniq@gmail.com Sun, et al. Expires November 7, 2011 [Page 8] Internet-Draft Contents Transition May 2011 Qian Liu China Telecom ChangSha, Hunan 410011 China Phone: +86 731 8226 0127 Email: 18973133999@189.cn Dong Liu BII Group Beijing, 100028 China Phone: +86 138-0103-2487 Email: dliu@biigroup.com Sun, et al. Expires November 7, 2011 [Page 9]