Network Working Group F. Xia Internet-Draft B. Sarikaya Expires: July 14, 2012 Huawei USA January 11, 2012 DHCPv4 Options for Home Information Discovery in Dual Stack MIPv6 draft-xia-mext-hioptv4-04.txt Abstract This document defines DHCPv4 options for dynamic discovery of home network information in Dual Stack Mobile IPv6. New DHCPv4 options are defined which allow a mobile node to request the home agent IPv4/v6 address, FQDN, or home network prefix and obtain it via the DHCPv4 response. 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 July 14, 2012. Copyright Notice Copyright (c) 2012 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. Xia & Sarikaya Expires July 14, 2012 [Page 1] Internet-Draft DHCPv4 Options for DSMIPv6 January 2012 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Home Network Information Discovery Using DHCPv6 . . . . . . . 4 4. DHCPv4 options for HA Dynamic Discovery . . . . . . . . . . . 4 4.1. Home Network Information Option . . . . . . . . . . . . . 4 4.2. DSMIP6 DHCPv4 Relay Agent Option . . . . . . . . . . . . . 5 4.3. Common Sub-options . . . . . . . . . . . . . . . . . . . . 6 5. Appearance of the options . . . . . . . . . . . . . . . . . . 8 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 7. IANA considerations . . . . . . . . . . . . . . . . . . . . . 8 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 9.1. Normative References . . . . . . . . . . . . . . . . . . . 9 9.2. Informative References . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10 Xia & Sarikaya Expires July 14, 2012 [Page 2] Internet-Draft DHCPv4 Options for DSMIPv6 January 2012 1. Introduction Before a mobile node can exchange Mobile IPv6 signaling with a home agent (HA), it should either know the IP address of the home agent via pre-configuration, or dynamically discover it. For dynamic discovery, new Dynamic Host Configuration Protocol for IPv6 (DHCPv6) options are defined in [I-D.ietf-mip6-hiopt] which allow a mobile node to request the home agent IPv4/ IPv6 address, Fully Qualified Domain Name (FQDN), or home network prefix, collectively called home network information and obtain it via the DHCPv6 response. Mobile IPv6 Support for Dual Stack Hosts and Routers (DSMIPv6) extends Mobile IPv6 specification [RFC3775] to allow the registration of IPv4 addresses and the transport of packets over IPv4 tunnels between mobile nodes and home agents ([RFC5555]). DSMIPv6 home agents are dual-stacked and can support IPv4 only mobile nodes. DSMIPv6 HA can support dual-stacked mobile nodes connected to the networks that are IPv4 only. Mobile nodes can register their IPv4 home and care-of addresses with HA and can tunnel IPv4 packets to the HA. With home network information discovery in DSMIPv6, there are actually four different cases: o Discovering HA's IPv6 address with DHCPv6 for IPv6 only mobile nodes o Discovering HA's IPv4 address with DHCPv6 for dual-stacked mobile nodes in IPv6 network o Discovering HA's IPv4 address with DHCPv4 for IPv4 only mobile nodes o Discovering HA's IPv6 address with DHCPv4 for dual-stacked mobile nodes in IPv4 network The first two cases are dealt with in [I-D.ietf-mip6-hiopt], while the last two cases are specified in this document. DHCPv4 options are defined based on DHCPv4 protocol specified in [RFC2131]. 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]. Xia & Sarikaya Expires July 14, 2012 [Page 3] Internet-Draft DHCPv4 Options for DSMIPv6 January 2012 3. Home Network Information Discovery Using DHCPv6 The following DHCPv6 options and their sub-options are used for dynamic discovery of the home agent's IPv4/IPv6 address, IPv6 home network prefix, or FQDN information in DSMIPv6: Home Network Information Option This option allows the exchange of home network information between the mobile node (DHCPv6 client) and the DHCPv6 server. It is used to indicate the target home network requested by the mobile node to the DHCPv6 server. It also conveys the home network information assigned by the DHCPv6 server to the mobile node as a response. MIP6 Relay Agent Option This option carries the home network information for the mobile node from the DHCPv6 relay agent to the DHCPv6 server. This is needed in case when the NAS is collocated with the DHCPv6 relay agent and the NAS gets the home network information from external AAA servers. MIP6 Relay Agent option is added to DHCPv6 message when the NAS/DHCP relay agent relays DHCPv6 request message from the mobile node to the DHCPv6 server. Being populated with this information, the DHCPv6 server uses Home Network Information Option to reply to the mobile node. Common Sub-options This sub-option is a container for a home network parameter in the Home Network Information option. In this document, Home Network Information Option and DSMIP6 DHCPv4 Relay Agent Option for DHCPv4 are defined in Section 4.1 and Section 4.2, respectively. These options carry the information such as IPv4 address of the dual-stacked home agent, IPv6 home network prefix, IPv6 home agent address, FQDN of HA and Home network identifier. Common Sub-options are defined in Section 4.3. 4. DHCPv4 options for HA Dynamic Discovery 4.1. Home Network Information Option The option allows the exchange of home network information between the mobile node (DHCPv4 client) and the DHCPv4 server. It is used to indicate the target home network requested by the mobile node to the Xia & Sarikaya Expires July 14, 2012 [Page 4] Internet-Draft DHCPv4 Options for DSMIPv6 January 2012 DHCPv4 server. It also conveys the home network information assigned by the DHCPv4 server to the mobile node as a response. 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | option-code | option-length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Id-type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sub-options | | ... ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Option-code OPTION_DSMIP6_HNINF (TDB) Option-len Length of the 'options' field in octets; MUST be a multiple of four (4). Id-type The type of Home Network Information. 0 Visited domain (local ASP) 1 Target MSP 2 No preference by the mobile node Sub-options A series of sub-options as defined in Section 4.3. 4.2. DSMIP6 DHCPv4 Relay Agent Option This option carries the home network information for the mobile node from the DHCPv4 relay agent to the DHCPv4 server. Xia & Sarikaya Expires July 14, 2012 [Page 5] Internet-Draft DHCPv4 Options for DSMIPv6 January 2012 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | option-code | option-length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sub-options | | ... ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Option-code OPTION_DSMIP6_RELAY (TBD) Option-len Length of the 'options' field in octets; MUST be a multiple of four (4). Sub-options A series of sub-options as defined in Section 4.3. 4.3. Common Sub-options This sub-option is a container for a home network parameter in the Home Network Information option or in the DSMIP6 DHCPv4 Relay Agent option. Xia & Sarikaya Expires July 14, 2012 [Page 6] Internet-Draft DHCPv4 Options for DSMIPv6 January 2012 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sub-opt-code | Sub-opt-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . . Home Network Parameter . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Sub-opt-code A 16-bit unsigned integer for the type of the following Home Network Parameter field. Possible values are: 0 Reserved 1 Home network identifier 2 IPv6 home network prefix 3 IPv6 home agent address 4 IPv4 address of the dual-stacked home agent 5 Home agent FQDN 6 .. (2^16-1) Reserved Sub-opt-len The length of the Home Network Parameter field in units of octets. Home Network Parameter The provided home network information according to the Sub-opt-code. This is encoded as specified below. Mobile node MUST set the Sub-opt-code to 1 in the requesting Home Network Information option. Mobile node MUST NOT set the Sub-opt- code to any other value. DHCPv4 Relay Agent or DHCP server MAY set the Sub-opt-code to 1, 2, 3, 4, and 5 as needed. When the Sub-opt-code is set to 1 in the request, the Home Network Parameter field MUST contain an identifier to specify the home network requested by the mobile node. This field MUST be set in the Xia & Sarikaya Expires July 14, 2012 [Page 7] Internet-Draft DHCPv4 Options for DSMIPv6 January 2012 form of a FQDN [RFC1035], encoded as specified in Section 8 of [RFC3315]. This sub-option in the request SHOULD be copied into the Home Network Information option returned in the reply. When the Sub-opt-code is set to 2, the Home Network Parameter field MUST include the 8-bit Prefix-Len followed by the 128-bit IPv6 Home Network Prefix. The Prefix-Len information indicates the number of leading bits in the IPv6 Home Network Prefix that are valid. The IPv6 Home Network Prefix information may be used to allow the mobile node to determine whether the home agent information received via DHCPv6 corresponds to a home agent on-link or not. When the Sub-opt-code is set to 3, the Home Network Parameter field MUST contain the 128-bit IPv6 address of the home agent. When the Sub-opt-code is set to 4, the Home Network Parameter field MUST contain the 32-bit IPv4 address of the dual-stacked home agent. When the Sub-opt-code is set to 5, it MUST contain the FQDN of the home agent as described in Section 8 of [RFC3315]. 5. Appearance of the options The Home Network Information Option MUST NOT appear in any message other than the following messages: DHCPDISCOVER, DHCPOFFER, DHCPREQUEST, DHCPACK,DHCPINFORM. The DSMIP6 DHCPv4 Relay Agent Option MUST NOT appear in any message other than the following messages: DHCPDISCOVER, DHCPREQUEST, DHCPINFORM. 6. Security Considerations The security considerations in [RFC2131] and [RFC2132]apply. Special considerations in [I-D.ietf-mip6-hiopt] are also applicable. 7. IANA considerations IANA is requested to assign the OPTION_DSMIP6_HNINF and OPTION_DSMIP6_RELAY Option Codes for DHCPv4 in the registry maintained. Xia & Sarikaya Expires July 14, 2012 [Page 8] Internet-Draft DHCPv4 Options for DSMIPv6 January 2012 8. Acknowledgements The authors are grateful to Tomek Mrugalski and Ted Lemon for their constructive comments that helped us improve the draft. 9. References 9.1. Normative References [RFC1981] McCann, J., Deering, S., and J. Mogul, "Path MTU Discovery for IP version 6", RFC 1981, August 1996. [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. [RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor Extensions", RFC 2132, March 1997. [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. [RFC1035] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, November 1987. [RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in IPv6", RFC 3775, June 2004. [RFC5555] Soliman, H., "Mobile IPv6 Support for Dual Stack Hosts and Routers", RFC 5555, June 2009. 9.2. Informative References [I-D.ietf-mip6-hiopt] Jang, H., Yegin, A., Chowdhury, K., and J. Choi, "DHCP Options for Home Information Discovery in MIPv6", draft-ietf-mip6-hiopt-17 (work in progress), May 2008. Xia & Sarikaya Expires July 14, 2012 [Page 9] Internet-Draft DHCPv4 Options for DSMIPv6 January 2012 Authors' Addresses Frank Xia Huawei USA 1700 Alma Dr. Suite 500 Plano, TX 75075 Phone: +1 972-509-5599 Email: xiayangsong@huawei.com Behcet Sarikaya Huawei USA 5340 Legacy Dr. Suite 175 Plano, TX 75074 Phone: Email: sarikaya@ieee.org Xia & Sarikaya Expires July 14, 2012 [Page 10]