Internet Engineering Task Force (IETF) H. Jang Request for Comments: 6610 KISTI Category: Standards Track A. Yegin ISSN: 2070-1721 Samsung K. Chowdhury Radio Mobile Access, Inc. J. Choi Samsung T. Lemon Nominum May 2012 DHCP Options for Home Information Discovery in Mobile IPv6 (MIPv6)
AbstractThis document defines a DHCP-based scheme to enable dynamic discovery of Mobile IPv6 home network information. New DHCP options are defined that allow a mobile node to request the home agent IP address, Fully Qualified Domain Name (FQDN), or home network prefix and obtain it via the DHCP response. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6610. 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. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. 1. Introduction ....................................................3 2. Terminology .....................................................3 3. DHCP Options for Home Network/Agent Dynamic Discovery ...........4 3.1. MIPv6 Home Network ID FQDN Option ..........................4 3.2. Home Network Information Options ...........................5 3.2.1. MIPv6 Visited Home Network Information Option .......5 3.2.2. MIPv6 Identified Home Network Information Option ....6 3.2.3. MIPv6 Unrestricted Home Network Information Option ..6 3.3. MIPv6 Home Network Prefix Option ...........................7 3.4. MIPv6 Home Agent Address Option ............................7 3.5. MIPv6 Home Agent FQDN Option ...............................8 4. Option Usage ....................................................9 4.1. Mobile Node Behavior .......................................9 4.1.1. Requesting MIPv6 Configuration ......................9 4.1.2. Processing MIPv6 Configuration Information .........10 4.2. Relay Agent Behavior ......................................11 4.3. DHCP Server Behavior ......................................12 4.4. Home Agent Discovery Using a Network Access Server ........12 5. Security Considerations ........................................13 6. IANA Considerations ............................................14 7. Acknowledgments ................................................14 8. References .....................................................14 8.1. Normative References ......................................14 8.2. Informative References ....................................15
RFC6275] describes how home agents can be dynamically discovered by mobile nodes that know the home network prefix. This scheme does not work when prefix information is not already available to the mobile node. This document specifies extensions to DHCPv6 [RFC3736] [RFC3315] to deliver the home agent information to the mobile node in the form of the IP address of the home agent or the Fully Qualified Domain Name (FQDN) [RFC1035] of the home agent. The information delivered to the mobile node may also include the home prefix for the mobile node. The solution involves defining new DHCP options to carry home network prefixes, home agent IP addresses, and FQDN information. The mobile node MAY also use the home prefix to discover the list of home agents serving the home prefix using the Dynamic Home Agent Address Discovery mechanism specified in [RFC6275]. As part of configuring the initial TCP/IP parameters, a mobile node can find itself a suitable home agent. Such a home agent might reside in the access network to which the mobile node connects or in a home network with which the mobile node is associated. A mobile node can indicate its home network identity when roaming to a visited network in order to obtain the MIPv6 bootstrap parameters from the home network. As an example, the visited network may determine the home network of the mobile node based on the realm portion of the NAI (Network Access Identifier) [RFC4282] used in access authentication [RFC5447]. The mobile node may or may not be connected to the "home" network when it attempts to learn Mobile IPv6 home network information. This allows operators to centrally deploy home agents while being able to bootstrap mobile nodes that are already roaming. This scenario also occurs when Hierarchical Mobile IPv6 (HMIPv6) [RFC5380] is used, where the mobile node is required to discover the MAP (a special home agent) that is located multiple hops away from the mobile node's attachment point. RFC2119].
General mobility terminology can be found in [RFC3753]. The following additional terms, as defined in [RFC4640], are used in this document: Access Service Provider (ASP): A network operator that provides direct IP packet forwarding to and from the mobile node. Mobility Service Provider (MSP): A service provider that provides Mobile IPv6 service. In order to obtain such service, the mobile node must be authenticated and authorized to use the Mobile IPv6 service. Mobility Service Authorizer (MSA): A service provider that authorizes Mobile IPv6 service. Section 2.3.2 of "Mobile IPv6 Support for Dual Stack Hosts and Routers" [RFC5555]. The names of options listed in this section all start with MIPv6, in order to differentiate them from other DHCP options that might have similar names. However, throughout the rest of this document, the options are referred to by name without the MIPv6 prefix, for brevity.
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_MIP6_HNIDF | Option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | Home Network Identifier FQDN | . . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Option-code: OPTION_MIP6_HNIDF (49) Option-len: Length of option, per RFC 3315 Home Network Identifier FQDN: A Fully Qualified Domain Name (FQDN) that identifies a mobile IP home network for which the client is seeking configuration information. This is encoded in accordance with RFC 3315, Section 8, "Representation and Use of Domain Names".
Option-code: OPTION_MIP6_VDINF (50) Option-len: Length of option, per RFC 3315 Options: One or more options, specifying information about the local ASP (visited domain). RFC 3315 Options: One or more options, specifying information about the home network identified by a Home Network Identifier FQDN option sent by a mobile node.
Option-code: OPTION_MIP6_UDINF (70) Option-len: Length of option, per RFC 3315 Options: One or more options, specifying information about some home network as specified by the DHCP server administrator. RFC 3315 Prefix-len: Length of prefix Prefix: Home Network Prefix RFC6052]. This option should only appear in one of the Home Network Information options.
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_MIP6_HAA | Option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | Address | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Option-code: OPTION_MIP6_HAA (72) Option-len: Length of option, per RFC 3315 Address: IP Address of home agent RFC 3315 Address: FQDN resolving to one or more IPv4 and/or IPv6 addresses for the home agent. This is encoded in accordance with RFC 3315, Section 8, "Representation and Use of Domain Names".
RFC3315]. RFC3315] or a stateless configuration exchange [RFC3736]. Mobile nodes that obtain MIPv6 configuration information using a stateful configuration exchange SHOULD include the same options in every message they send to the DHCP server. Mobile nodes that obtain MIPv6 configuration using a stateless exchange MAY omit MIPv6 configuration from some exchanges, but SHOULD reconfigure whenever a change in the attached network is detected. If the DHCP server responds to a MIPv6-related stateless configuration request with an Information Request Timer option, the mobile node SHOULD attempt to reconfigure when the IRT expires. A mobile node using stateless configuration may try to perform home network information discovery when it lacks home network information for MIPv6 or needs to change the home agent for some reason. For example, this may be necessary to recover from the failure of an existing home agent or to use the local home agent located in the network where the mobile node is currently attached. Note that despite the home information discovery procedure, the mobile node may continue to use the old home agent, in order to avoid losing current sessions.
network information that pertains to the currently visited network. This type can be used to discover local home agents in the local ASP. If the mobile node requests the Identified Home Network Information option, this indicates that it is interested in learning the home network information that pertains to a specified realm. This type can be used to discover home agents that are hosted by a user's home domain or by any target domain. A mobile node requesting the Identified Home Network Information option MUST include a Client Home Network ID FQDN option identifying the MSP being identified. The target MSP can be a mobile node's home MSP or any MSP that has a trusted roaming relationship with the mobile node's MSA. If the mobile node has no preference as to the home network with which it should be configured, it SHOULD request the Unrestricted Home Network Information option, and SHOULD NOT request either the Visited Home Network Information option or the Identified Home Network Information option. A client that wishes to be configured with both the Visited Home Network Information option and the Identified Home Network Information option may request both options in the Option Request Option. A client may request information about more than one identified domain by requesting the Identified Home Network Information option in the ORO and including more than one Home Network ID FQDN option. A client that sends more than one Home Network ID FQDN option MUST request the Home Network ID option in the ORO.
If the client finds an IPv4-Embedded IPv6 address in a Home Agent Address option, it may only use this address to communicate over IPv4. If a Home Network Information option does not contain complete configuration information, the client MUST silently discard that Home Network Information option. If the client receives any Home Network ID FQDN options, Home Network Prefix options, Home Agent Address options, or Home Agent FQDN options that are not encapsulated in one of the three types of Home Network Information options, it MUST silently discard these options. The DHCP client must pass whatever configuration information it receives to the appropriate mobile IP implementation on the mobile node. How this is done, and what the mobile IP implementation on the mobile node does with this information, is outside the scope of this document. As described later in this section, servers may provide more than one Home Network Information option or multiple Home Agent Prefix, Home Agent Address, or Home Agent FQDN options. When provided with multiple Visited Home Network Information options or Unrestricted Home Network Information options of the same type, or with multiple sub-options within such an option, the mobile node SHOULD choose the first one that it can employ. If the DHCP client on a mobile node receives any Home Network Prefix options, Home Agent Address option, or Home Agent FQDN option that are not contained within Home Network Information options, the DHCP client MUST silently discard these options. RFC6422]. If the DHCP relay agent includes any Identified Home Network Information options, these options MUST correspond to home networks identified in Home Network ID FQDN options in the client request. In addition, each Identified Home Network Information option must contain a Home Network ID FQDN option identical to the one sent by the client, to identify the network to the client. No special handling is required when processing relay-reply messages.
RFC3315] and depends on operator configuration. No special processing is required for Visited Home Network Information options or Unrestricted Home Network Information options. RFC5447] describes the complete procedure for home agent assignment among the mobile node, NAS (Network Access Server), DHCP, and Authentication, Authorization, and Accounting (AAA) entities for the bootstrapping procedure in the integrated scenario. A NAS is assumed to be co-located with a DHCP relay agent or a DHCP server in this solution. In a network where the NAS is not co-located with a DHCP relay or a server, the server may not be provided with the home network information from the NAS; therefore,
it may either fail to provide information or provide home information that has been pre-configured by the administrator or that is acquired through a mechanism that is not described in this document.
http://www.iana.org/assignments/dhcpv6-parameters: 49: OPTION_MIP6_HNIDF for the Home Network ID FQDN option 50: OPTION_MIP6_VDINF for the Visited Home Network Information option 69: OPTION_MIP6_IDINF for the Identified Home Network Information option 70: OPTION_MIP6_UDINF for the Unrestricted Home Network Information option 71: OPTION_MIP6_HNP for the Home Network Prefix option 72: OPTION_MIP6_HAA for the Home Agent Address option 73: OPTION_MIP6_HAF for the Home Agent FQDN option [RFC1035] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, November 1987. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, 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. [RFC3736] Droms, R., "Stateless Dynamic Host Configuration Protocol (DHCP) Service for IPv6", RFC 3736, April 2004.
[RFC4282] Aboba, B., Beadles, M., Arkko, J., and P. Eronen, "The Network Access Identifier", RFC 4282, December 2005. [RFC5555] Soliman, H., "Mobile IPv6 Support for Dual Stack Hosts and Routers", RFC 5555, June 2009. [RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X. Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052, October 2010. [RFC6275] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support in IPv6", RFC 6275, July 2011. [RFC6422] Lemon, T. and Q. Wu, "Relay-Supplied DHCP Options", RFC 6422, December 2011. [RFC3753] Manner, J. and M. Kojo, "Mobility Related Terminology", RFC 3753, June 2004. [RFC4640] Patel, A. and G. Giaretta, "Problem Statement for bootstrapping Mobile IPv6 (MIPv6)", RFC 4640, September 2006. [RFC5380] Soliman, H., Castelluccia, C., ElMalki, K., and L. Bellier, "Hierarchical Mobile IPv6 (HMIPv6) Mobility Management", RFC 5380, October 2008. [RFC5447] Korhonen, J., Bournelle, J., Tschofenig, H., Perkins, C., and K. Chowdhury, "Diameter Mobile IPv6: Support for Network Access Server to Diameter Server Interaction", RFC 5447, February 2009.