Network Working Group Q. Sun Internet-Draft Z. Zhang Intended status: Informational China Telecom Expires: December 27, 2015 Q. Zhao Beijing University of Posts and Telecommunications S. Jiang Huawei Technologies Co., Ltd X. Lee Y. Fu CNNIC June 25, 2015 Running Multiple PLATs in 464XLAT draft-sun-v6ops-xlat-multi-02 Abstract The IPv6 transition has been an ongoing process throughout the world due to the exhaustion of the IPv4 address space. The 464XLAT [RFC6877] provides a solution with limited IPv4 connectivity across an IPv6-only network, and the android system (version 2.3 and above) has already implemented the 464XLAT and the Prefix discovery solution [RFC7050]. However, the current 464XLAT architecture can only deal with the scenario with single PLAT in the network. When operator deploys multiple PLATs with different Pref64 prefixes, 464XLAT cannot cope with multiple prefixes for different destination addresses. This document describes the architecture with multiple PLATs and also the deployment considerations. 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 December 27, 2015. Sun, et al. Expires December 27, 2015 [Page 1] Internet-Draft Running Multiple PLATs in 464XLAT June 2015 Copyright Notice Copyright (c) 2015 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 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 . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Requirement of Multiple PLATs in 464XLAT . . . . . . . . . . 3 4. Overall Architecture of multiPLATs in 464XLAT . . . . . . . . 4 4.1. Prefix Management Server . . . . . . . . . . . . . . . . 4 4.2. Enhanced CLAT for multiPLAT . . . . . . . . . . . . . . . 5 5. Deployment Considerations . . . . . . . . . . . . . . . . . . 6 5.1. Prefix Management . . . . . . . . . . . . . . . . . . . . 6 5.2. DNS64 Consistency . . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 7. Security Considerations . . . . . . . . . . . . . . . . . . . 6 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 9.1. Normative References . . . . . . . . . . . . . . . . . . 7 9.2. Informative References . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction The exhaustion of the IPv4 address space has been a practical problem that providers are facing today. Network address migration to IPv6 is ongoing or upcoming throughout the world. The 464XLAT architecture uses the IPv4/IPv6 translation technology standardized in [RFC6145] and [RFC6146]. It encourages the IPv6 transition by making IPv4 service reachable across IPv6-only networks and providing IPv6 and IPv4 connectivity to IPv4 or IPv6 servers and peers of single-stack. The android system (version 4.3 and above) has already implemented the 464XLAT [RFC6877] and the Prefix discovery method in [RFC7050]. Sun, et al. Expires December 27, 2015 [Page 2] Internet-Draft Running Multiple PLATs in 464XLAT June 2015 However, as described in section 6.3 [RFC6877], the CLAT will use the PLAT-side translation IPv6 prefix as the destination of all translation packets that require stateful translation to the IPv4 Internet. The Prefix Discovery method [RFC7050] cannot deal with the scenario when different PLATs are using with different Pref64 prefixes. This document describes the solution of 464XLAT architecture with multiple PLATs and some deployment considerations 2. Terminology 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]. This document use the terminologies defined in [RFC6877] and [RFC7050]. 3. Requirement of Multiple PLATs in 464XLAT As defined in [RFC6147], it allows the implementations of DNS64 to be able to map specific IPv4 address ranges to separate Pref64::/n prefixes. That allows handling with special use of IPv4 addresses [RFC6890]. Therefore, operator may deploy multiple NAT64s (PLATs in 464XLAT) for different ranges of IPv4 servers. For example, one PLAT "A" is used when accessing IPv4-only servers in the data center, and a different PLAT "B" is used for Internet access as described in Figure 1. These two PLATs may have implemented different ALG types and different QoS treatment. PLAT "A" ----- IPv4-only servers in a data center / IPv6-only node---< \ PLAT "B" ----- IPv4 Internet Figure 1: Use case of MultiPLAT In this use case, one end user would use multiple Pref64 prefixes for different destinations. Another use case to deploy multiple PLATs is for load balancing. For example, PLAT "A" would serve approximately half of the subscribers in one network, while PLAT "B" would serve the other half as described in Figure 2. Sun, et al. Expires December 27, 2015 [Page 3] Internet-Draft Running Multiple PLATs in 464XLAT June 2015 PLAT "A" ----- half of the subscribers / IPv6-only node---< \ PLAT "B" ----- the other half of the subscribers Figure 2: Use case of MultiPLAT for load balancing In this use case, one end user would still get one Pref64 for all destinations, but it still needs a management system to allocate different Pref64 prefixes for different users. 4. Overall Architecture of multiPLATs in 464XLAT The overall architecture of multiPLATs in 464XLAT is depicted as Figure 3. It consists of a Prefix Management Server, enhanced CLAT, and multiple PLATs. The PLAT in this architecture has no difference between the one in 464XLAT in [RFC6877]. +-----------------+ +----|Pref Mangt Server| | +-----------------+ | +------+ +------+ | +-----+ / \ | CLAT |------+------+PLAT1+----| network1 | +------+ | +-----+ \ / | +------+ | +------+ | +-----+ / \ +------+PLAT2+----| network2 | +-----+ \ / +------+ Figure 3: Architecture of multiPLATs in 464XLAT 4.1. Prefix Management Server The Prefix Management Server includes the following modulars as described in Figure 4. Sun, et al. Expires December 27, 2015 [Page 4] Internet-Draft Running Multiple PLATs in 464XLAT June 2015 +---------------------------------------------+ | +---------------+ +-----------------+ | | |Pref64 Magt | |v4addrRange Magt | | | +---------------+ +-----------------+ | | +---------------+ +-----------------+ | | |IPv6Pref Magt | | Prefix Discovery| | | +---------------+ +-----------------+ | | +----------------------+ | | |Policy Configuration | | | +----------------------+ | +---------------------------------------------+ Figure 4: The implementation modulat of Prefix Management Server It would be configured with the policy to allocate multiple Pref64s. There may be different policies to apply. For example, it may map specific IPv4 destination address ranges to separate Pref64 prefixes, or map specific IPv6 source address ranges to separate Pref64 prefixes, or map both destination IPv4 address and source IPv6 address to Pref64 prefixes. The policy in Prefix Management Server should be consistent with the one of the PLAT deployment. The prefix discovery method should be able to cope with multiple Pref64 prefixes. It may implement PCP based prefix discovery method [RFC7225] to allocate multiple Pref64 prefixes. 4.2. Enhanced CLAT for multiPLAT In addition to satisfy the requirements of existing CLAT, the enhanced CLAT for multiPLAT should also implement the following modulars as described in figure 5: +---------------------------------------------+ | +---------------+ +-----------------+ | | |Pref64 Magt | |v4addrRange Magt | | | +---------------+ +-----------------+ | | +-----------------+ | | | Prefix Discovery| | | +-----------------+ | +---------------------------------------------+ Figure 5: The implementation modulars of enhanced CLAT The prefix discovery method should be consistent with the one in the Prefix Management Server. The Pref64 Management modular will extract the multiple Pref64 prefixes from the prefix discovery procedure and the v4addrRange Management modular will store the corresponding IPv4 address ranges. The prefix discovery method will get multiple Pref64 Sun, et al. Expires December 27, 2015 [Page 5] Internet-Draft Running Multiple PLATs in 464XLAT June 2015 prefixes after the process of authentication and IPv6 address allocation. Then, the CLAT will use the Pref64 prefix as the destination for specific IPv4 address ranges. The translation and DNS modular is the same with the traditional XLAT in [RFC6877]. 5. Deployment Considerations 5.1. Prefix Management The prefix management modular is important for multiPLATs in 464XLAT. However, since it would compare the destination address range with each packet in CLAT, it might affect the performance efficiency of the client. So, operators should limit the number of address ranges, and aggregate the addresses into a larger address range. Besides, there might also be a maximum limit configured in CLAT on the number of Pref64 prefixes and the number of address ranges. When the number of address ranges exceeds the limit, the CLAT may ignore the next Pref64 prefixes and use a default prefix for the rest of destinations. However, this may cause issues for unexpected results. 5.2. DNS64 Consistency 464XLAT does not require DNS64 [RFC6147] when IPv4 host sends IPv4 packets to reach IPv4 servers. But 464XLAT networks may use DNS64 to enable single stateful translation [RFC6146]. In this case, the configuration policy in DNS64 should be consistent with the Prefix Management Server. For example, how to map different IPv4 address ranges to Pref64 prefixes and IPv6 prefixes for Preference prefixes. 6. IANA Considerations This document has no IANA actions. 7. Security Considerations TO BE COMPLETED 8. Acknowledgements The authors would like to thank the following individuals who have participated in the drafting, review, and discussion of this memo: TO BE COMPLETED This document was produced using the xml2rfc tool [RFC2629]. Sun, et al. Expires December 27, 2015 [Page 6] Internet-Draft Running Multiple PLATs in 464XLAT June 2015 9. References 9.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation Algorithm", RFC 6145, April 2011. [RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful NAT64: Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers", RFC 6146, April 2011. [RFC6147] Bagnulo, M., Sullivan, A., Matthews, P., and I. van Beijnum, "DNS64: DNS Extensions for Network Address Translation from IPv6 Clients to IPv4 Servers", RFC 6147, April 2011. [RFC6877] Mawatari, M., Kawashima, M., and C. Byrne, "464XLAT: Combination of Stateful and Stateless Translation", RFC 6877, April 2013. [RFC7050] Savolainen, T., Korhonen, J., and D. Wing, "Discovery of the IPv6 Prefix Used for IPv6 Address Synthesis", RFC 7050, November 2013. 9.2. Informative References [RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, June 1999. [RFC6890] Cotton, M., Vegoda, L., Bonica, R., and B. Haberman, "Special-Purpose IP Address Registries", BCP 153, RFC 6890, April 2013. [RFC7225] Boucadair, M., "Discovering NAT64 IPv6 Prefixes Using the Port Control Protocol (PCP)", RFC 7225, May 2014. Authors' Addresses Qiong Sun China Telecom No.118 Xizhimennei Street, Xicheng District Beijing 100035 P.R. China Email: sunqiong@ctbri.com.cn Sun, et al. Expires December 27, 2015 [Page 7] Internet-Draft Running Multiple PLATs in 464XLAT June 2015 Zhirong Zhang China Telecom No.118 Xizhimennei Street, Xicheng District Beijing 100035 P.R. China Email: zhangzhr@ctbri.com.cn Qin Zhao Beijing University of Posts and Telecommunications Beijing 100876 P.R. China Email: zhaoq@bupt.edu.cn Sheng Jiang Huawei Technologies Co., Ltd Q14, Huawei Campus, No.156 Beiqing Road Hai-Dian District, Beijing, 100095 P.R. China Email: jiangsheng@huawei.com Xiaodong Lee CNNIC No.4 South 4th Street, Zhongguancun Hai-Dian District, Beijing, 100190 P.R. China Email: xl@cnnic.cn Yu Fu CNNIC No.4 South 4th Street, Zhongguancun Hai-Dian District, Beijing, 100190 P.R. China Email: fuyu@cnnic.cn Sun, et al. Expires December 27, 2015 [Page 8]