DHC Working Group W. Wang Internet-Draft L. Zhang Intended status: Standards Track X. Que Expires: March 19, 2015 BUPT University L. Li Tsinghua University Y. Wang BUPT University September 15, 2014 Discovery of the IPv6 Prefix in 464XLAT draft-wang-v6ops-xlat-prefix-discovery-00 Abstract The 464XLAT[RFC6877] provides a solution with limited IPv4 connectivity across an IPv6-only network. In the architecture, the CLAT must discover the PLAT-side translation IPv6 prefix. This document defines a mechanism for CLAT to learn the IPv6 prefix used for protocol translation on an access network. 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 March 19, 2015. Copyright Notice Copyright (c) 2014 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 Wang, et al. Expires March 19, 2015 [Page 1] Internet-Draft IPv6 Prefix Discovery September 2014 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. Requirements Language . . . . . . . . . . . . . . . . . . . . 2 3. Solution Overview . . . . . . . . . . . . . . . . . . . . . . 3 4. Client-Server Interaction . . . . . . . . . . . . . . . . . . 3 5. DHCPv6 Options . . . . . . . . . . . . . . . . . . . . . . . 4 5.1. PLAT IPv6 PREFIX Option . . . . . . . . . . . . . . . . . 4 6. Security Considerations . . . . . . . . . . . . . . . . . . . 5 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 8.1. Normative References . . . . . . . . . . . . . . . . . . 5 8.2. Informative References . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction 464XLAT describes an IPv4-over-IPv6 solution as one of the techniques for IPv4 service extension and encouragement of IPv6 deployment. The 464XLAT architecture uses IPv4/IPv6 translation 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 single-stack IPv4 or IPv6 servers and peers. Discovery of the IPv6 Prefix Used for IPv6 Address Synthesis [RFC7050] describes a method for detecting the presence of DNS64 and for learning the IPv6 prefix used for protocol translation on an access network. But it is difficult and depends on DNS64. This document defines a mechanism for CLAT to learn the IPv6 prefix used for protocol translation on an access network. One new DHCPv6 option is defined to inform the CLAT of the IPv6 prefix used for IPv6 address synthesis. 2. 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]. Wang, et al. Expires March 19, 2015 [Page 2] Internet-Draft IPv6 Prefix Discovery September 2014 3. Solution Overview In the 464XLAT architecture, the CLAT must discover the PLAT-side translation IPv6 prefix used as a destination of the PLAT. The CLAT will use this prefix as the destination of all translation packets that require stateful translation to the IPv4 Internet. The CLAT implements OPTION_V6_PLATPREFIX, which is a DHCPv6 option containing the IPv6 prefix used as a destination of the PLAT. The client includes this option within the ORO option in its DHCPv6 request, indicates its support for the IPv6 prefix to the DHCP server. OPTION_V6_PLATPREFIX is also implemented by the server to identify the client which support IPv6 prefix. With this option, the server informs the client of the IPv6 prefix used as a destination of the PLAT. 4. Client-Server Interaction The following diagram shows the client/server message flow and how the DHCPv6 option OPTION_V6_PLATPREFIX is used. In each step, the relevant DHCPv6 message is given above the arrow and the OPTION_V6_PLATPREFIX below the arrow. Wang, et al. Expires March 19, 2015 [Page 3] Internet-Draft IPv6 Prefix Discovery September 2014 DHCPv6 Client DHCPv6 Server | Solicit | Step 1 |----------------------------------------------------->| | ORO with OPTION_V6_PLATPREFIX | | | | ADVERTISE | Step 2 |<-----------------------------------------------------| | OPTION_V6_PLATPREFIX (platv6-prefix with | | PLAT-side translation IPv6 prefix) | | | | REQUEST | Step 3 |----------------------------------------------------->| | OPTION_V6_PLATPREFIX (platv6-prefix with | | CLAT-side translation IPv6 prefix) | | | | REPLY | Step 4 |<-----------------------------------------------------| | OPTION_V6_PLATPREFIX (platv6-prefix with | | CLAT-side translation IPv6 prefix) | | | Figure 1: Server/Client Interaction Procedure The DHCPv6 Server and Client MAY implement the OPTION_V6_PLATPREFIX. A Client that intends to dynamically discover the PLAT-side translation IPv6 prefix SHOULD include the code of OPTION_V6_PLATPREFIX in the ORO when it sends a Solicit message. When a DHCPv6 server replies with a ADVERTISE message, it SHOULD include the platv6-prefix with PLAT-side transition IPv6 prefix. The OPTION_V6_PLATPREFIX is used by the server to inform the client of the PLAT-side transition IPv6 prefix. When the client sends a REQUEST message, it SHOULD include the platv6-prefix with CLAT-side translation IPv6 prefix. The OPTION_V6_PLATPREFIX is used by the client to inform the server of the transition IPv6 prefix. 5. DHCPv6 Options 5.1. PLAT IPv6 PREFIX Option Wang, et al. Expires March 19, 2015 [Page 4] Internet-Draft IPv6 Prefix Discovery September 2014 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPTION_V6_PLATPREFIX | option-length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | platv6-prelen | | +-+-+-+-+-+-+-+-+ platv6-prefix . . (variable length) . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ o option-code: OPTION_V6_PLATPREFIX (TBA1) o option-length: 1 + length of platv6-prefix, specified in bytes. o platv6-prelen: 8-bit field expressing the bit mask length of the IPv6 prefix specified in platv6-prefix. o platv6-prefix: The IPv6 prefix that the server uses to inform the client of the IPv6 prefix used for IPv6 address synthesis. 6. Security Considerations TBA 7. IANA Considerations This document defines one new DHCPv6 option, the OPTION_V6_PLATPREFIX option in Section 4. 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 8.2. Informative References [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M. Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3315, July 2003. Authors' Addresses Wang, et al. Expires March 19, 2015 [Page 5] Internet-Draft IPv6 Prefix Discovery September 2014 Wendong Wang BUPT University Beijing University of Posts and Telecommunications (BUPT) Beijing 100876 P.R.China Phone: +86-10-6228-1175 Email: wdwang@bupt.edu.cn Lanshan Zhang BUPT University Beijing University of Posts and Telecommunications (BUPT) Beijing 100876 P.R.China Phone: +86-13146885878 Email: zls326@sina.com Xirong Que BUPT University Beijing University of Posts and Telecommunications (BUPT) Beijing 100876 P.R.China Phone: +86-10-6228-3411 Email: rongqx@bupt.edu.cn Lishan Li Tsinghua University Beijing 100084 P.R.China Phone: +86-15201441862 Email: lilishan9248@126.com Yuqi Wang BUPT University Beijing University of Posts and Telecommunications (BUPT) Beijing 100876 P.R.China Email: wyqbupt@163.com Wang, et al. Expires March 19, 2015 [Page 6]