Network working group D. Guo Internet Draft X. Xu Category: Standard Track Huawei Technologies Expires: September 2010 March 1, 2010 IPv6 Host Configuration in 6rd Deployment draft-guo-softwire-6rd-ipv6-config-00 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. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on September 1, 2010. Copyright Notice Copyright (c) 2010 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. Guo, et al. Expires September 1, 2010 [Page 1] Internet-Draft IPv6 Host Configuration in 6rd Deployment March 2010 Abstract This document proposes two new DHCPv4 options which allow IPv6 hosts to obtain configuration information (e.g., DNS servers). The DHCPv6 Server Option in DHCPv4 provides the IPv6 address of DHCPv6 server to the 6rd CPE. In result the 6rd CPE can relay DHCPv6 requests to DHCPv6 servers. As an alternative, the IPv6 DNS Server Option is used in the scenario where hosts only need the information of IPv6 DNS servers. Conventions used in this document 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 RFC-2119 [RFC2119]. Table of Contents 1. Terminologies..................................................3 2. Introduction...................................................3 3. DHCPv6 Server Option in DHCPv4.................................4 4. IPv6 DNS Server Option in DHCPv4...............................5 5. Security Considerations........................................6 6. IANA Considerations............................................6 7. Acknowledgements...............................................6 8. References.....................................................6 8.1. Normative References......................................6 8.2. Informative References....................................7 Authors' Addresses................................................7 Guo, et al. Expires September 1, 2010 [Page 2] Internet-Draft IPv6 Host Configuration in 6rd Deployment March 2010 1. Terminologies 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 [RFC2119]. 2. Introduction IPv6 rapid deployment on IPv4 infrastructures (6rd)[RFC5569] enables a service provider to rapidly deploy IPv6 unicast service to customer sites via its IPv4 network. [I-D.ietf-softwire-ipv6-6rd] provides a method for automatic IPv6 prefix delegation to sites. However, there is no document which describes how the IPv6 hosts in 6rd obtain IPv6 configuration information automatically. In a typical 6rd scenario, a dual-stack host can obtain configuration information via DHCPv4. In such case, the IPv4 DNS server MUST support AAAA Resource Record (RR) query. For an IPv6-only host within a customer site, it would have to learn IPv6 configuration information through some automatic methods, e.g., Dynamic Host Configuration Protocol for IPv6 (DHCPv6)[RFC3315]. As described in [RFC3315], "...The client MUST use a link-local address assigned to the interface for which it is requesting configuration information as the source address in the header of the IP datagram." Since the link-local address can not travel through the 6rd domain, the CPE MUST act as a DHCPv6 relay agent (or a DHCPv6 server). Since 6rd CPEs derive the 6rd prefix from an extended DHCPv4 option, the DHCPv6 server addresses can be learnt in a similar way (i.e., via a new DHCPv4 option). As a result, IPv6 hosts can either get configuration information from the CPE (acting as a DHCPv6 server) directly or from a DHCPv6 server via the CPE (acting as a DHCP relay agent). Details about this new DHCPv4 option and the related procedure are described in Section 3. In case that the default DNS server is the only configuration information which the IPv6 hosts need, a to-be-defined IPv6 DNS Server Option in DHCPv4 could be used as an alternative to the above DHCPv4 option for DHCPv6 server. CPEs can learn the IPv6 DNS Server address(es) through this new DHCPv4 option. The hosts in turn learn the DNS server address information through the Router Advertisement mechanism [RFC5006] or the stateless DHCPv6 mechanism (here the CPE acts as a DHCP server). This new DHCPv4 option is described in Section 4. Guo, et al. Expires September 1, 2010 [Page 3] Internet-Draft IPv6 Host Configuration in 6rd Deployment March 2010 Note that the methods described in this document can also be used in other IPv6 migration scenarios, such as ISATAP [RFC5214]. 3. DHCPv6 Server Option in DHCPv4 The DHCPv6 Server Option is shown in Figure 1. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPT_DHCPv6 | Option-length | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | IPv6 Address(es) of DHCPv6 Server(s) | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: Stateless DHCPv6 Server Option Format Fields: OPT_DHCPv6 TBD. Option-length The length of the DHCP option in octets. IPv6 Address(es) of DHCPv6 Server(s) One or more 128-bit IPv6 addresses of the DHCPv6 servers. The DHCPv6 server is deployed in IPv6 network, DHCPv6 messages MUST pass through IPv4 network with 6rd encapsulation. IPv6 hosts behind the 6rd CPE SHOULD follow procedures depicted in Figure 2 when they use DHCPv6 to obtain configuration information: (1) The 6rd CPE acting as a DHCPv6 relay agent configures the DHCPv6 servers according to the obtained DHCPv6 Server Option from DHCPv4 server. Note that the CPE SHOULD have a 6rd address in order to behave as a relay agent. (2) When receiving a DHCPv6 Information-request packet from an IPv6 host, the 6rd CPE SHOULD relay the message according to Relay Agent Behavior defined in [RFC3315]. Guo, et al. Expires September 1, 2010 [Page 4] Internet-Draft IPv6 Host Configuration in 6rd Deployment March 2010 (3) The DHCPv6 Relay-forward message passes 6rd domain and is sent to DHCPv6 server. (4) 6rd CPE receives the DHCPv6 Relay-reply message encapsulated in a 6rd tunnel. (5) 6rd CPE relays the DHCPv6 reply message to IPv6 host. -Customer--> | <-IPv4 Provider Network-> |<-IPv6 Provider Network IPv6 6rd CPE DHCPv4 6rd DHCPv6 host (DHCPv6 relay ) Server border relay server ----+----------+--------------+------------+-----------+----- | | | | | | |DHCPv6 Option | | | (1) | | <----------> | | | | DHCPv6 | | | Information-request | | (2) | -------->| DHCPv6 Relay-forward | | | | in 6rd tunnel | | (3) | |==========================>|---------->| | | DHCPv6 Relay-reply | | | | in 6rd tunnel | | (4) | DHCPv6 |<==========================|<----------| | Reply | | | (5) | <--------| | | Figure 2: Auto-configure Procedures based on DHCPv6 in 6rd 4. IPv6 DNS Server Option in DHCPv4 The IPv6 DNS Server Option is depicted in Figure 3. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPT_IPv6_DNS | Option-length | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | IPv6 Address(es) of Default IPv6 DNS Server(s) | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: IPv6 DNS Server Option Format Guo, et al. Expires September 1, 2010 [Page 5] Internet-Draft IPv6 Host Configuration in 6rd Deployment March 2010 Fields: OPT_IPv6_DNS TBD. Option-length The length of the DHCP option in octets. IPv6 Address(es) of Default IPv6 DNS Server(s) One or more 128-bit IPv6 addresses of the DNS servers in IPv6 network. 5. Security Considerations To be defined. 6. IANA Considerations IANA is requested to allocate two DHCPv4 Option codes, one is for DHCPv6 Server Option and the other is for IPv6 DNS Server Option. 7. Acknowledgements To be defined. 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. [RFC2131] Droms R., "Dynamic Host Configuration Protocol", RFC 2131, March 1997. [RFC3315] Droms R., et al., "Dynamic Host Configure Protocol for IPv6", RFC3315, July 2003. [RFC3736] Droms R., "Stateless Dynamic Host Configuration Protocol (DHCP) Service for IPv6", RFC 3736, April 2004. [RFC5569] Despres, R., "IPv6 Rapid Deployment on IPv4 Infrastructures (6rd)", January 2010. Guo, et al. Expires September 1, 2010 [Page 6] Internet-Draft IPv6 Host Configuration in 6rd Deployment March 2010 [I-D.ietf-softwire-ipv6-6rd] Townsley W., et al., "IPv6 via IPv4 Service Provider Networks (6rd)", draft-ietf-softwire- ipv6-6rd-07(work in progress), February 2010. 8.2. Informative References [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, September 2007. [RFC5006] Jeong, J., "IPv6 Router Advertisement Option for DNS Configuration", RFC 5006, September 2007. [RFC5214] Templin, F., Gleeson, T., and D. Thaler, "Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)", RFC 5214, March 2008. Authors' Addresses Dayong Guo Huawei Technologies, No.3 Xinxi Rd., Shang-Di Information Industry Base, Hai-Dian District, Beijing 100085, P.R. China Phone: 86-10-82836077 Email: guoseu@huawei.com Xiaohu Xu Huawei Technologies, No.3 Xinxi Rd., Shang-Di Information Industry Base, Hai-Dian District, Beijing 100085, P.R. China Phone: +86 10 82836073 Email: xuxh@huawei.com Guo, et al. Expires September 1, 2010 [Page 7]