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Network Working Group                                            B. VolzRequest for Comments: 4580                           Cisco Systems, Inc.Category: Standards Track                                      June 2006Dynamic Host Configuration Protocol for IPv6 (DHCPv6)Relay Agent Subscriber-ID OptionStatus of This Memo   This document specifies an Internet standards track protocol for the   Internet community, and requests discussion and suggestions for   improvements.  Please refer to the current edition of the "Internet   Official Protocol Standards" (STD 1) for the standardization state   and status of this protocol.  Distribution of this memo is unlimited.Copyright Notice   Copyright (C) The Internet Society (2006).Abstract   This memo defines a new Relay Agent Subscriber-ID option for the   Dynamic Host Configuration Protocol for IPv6 (DHCPv6).  The option   allows a DHCPv6 relay agent to associate a stable "Subscriber-ID"   with DHCPv6 client messages in a way that is independent of the   client and of the underlying physical network infrastructure.Table of Contents1. Introduction ....................................................22. The Relay Agent Subscriber-ID Option ............................23. DHCPv6 Relay Agent Behavior .....................................34. DHCPv6 Server Behavior ..........................................35. Security Considerations .........................................46. IANA Considerations .............................................47. Acknowledgements ................................................48. References ......................................................48.1. Normative References .......................................48.2. Informative References .....................................4Volz                        Standards Track                     [Page 1]

RFC 4580               Relay Agent Subscriber-ID               June 20061.  Introduction   DHCPv6 [1] provides IP addresses and configuration information for   IPv6 clients.  It includes a relay agent capability, in which   processes within the network infrastructure receive multicast   messages from clients and relay them to DHCPv6 servers.  In some   network environments, it will be useful for the relay agent to add   information to the DHCPv6 message before relaying it.   The information that relay agents supply can also be used in the   server's decision-making about the addresses, delegated prefixes [2],   and configuration parameters that the client is to receive.   In many service-provider environments, it is believed to be desirable   to associate some provider-specific information with clients' DHCPv6   messages that is independent of the physical network configuration   and that the relay agent has learned through some means that is   outside the scope of this memo.2.  The Relay Agent Subscriber-ID Option   In complex service provider environments, there is a need to connect   a customer's DHCPv6 configuration with the customer's administrative   information.  The Relay Agent Subscriber-ID option carries a value   that can be independent of the physical network configuration through   which the subscriber is connected.  This value complements, and might   well be used in addition to, the network-based information.  The   "subscriber-id" assigned by the provider is intended to be stable as   customers connect through different paths, and as network changes   occur.   The subscriber-id information allows the service provider to assign/   activate subscriber-specific actions; e.g., assignment of specific IP   addresses, prefixes, DNS configuration, trigger accounting, etc.   This option is de-coupled from the access network's physical   structure, so a subscriber that moves from one access-point to   another, for example, would not require reconfiguration at the   service provider's DHCPv6 servers.   The subscriber-id information is only intended for use within a   single administrative domain and is only exchanged between the relay   agents and DHCPv6 servers within that domain.  Therefore, the format   and encoding of the data in the option is not standardized, and this   specification does not establish any semantic requirements on the   data.  This specification only defines the option for conveying this   information from relay agents to DHCPv6 servers.Volz                        Standards Track                     [Page 2]

RFC 4580               Relay Agent Subscriber-ID               June 2006   However, as the DHCPv4 Subscriber-ID suboption [3] specifies Network   Virtual Terminal (NVT) American Standard Code for Information   Interchange (ASCII) [4] encoded data, in environments where both   DHCPv4 [5] and DHCPv6 are being used, it may be beneficial to use   that encoding.   The format of the DHCPv6 Relay Agent Subscriber-ID option is shown   below:    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_SUBSCRIBER_ID      |         option-len            |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   .                                                               .   .                         subscriber-id                         .   .                                                               .   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+      option-code      OPTION_SUBSCRIBER_ID (38)      option-len       length, in octets, of the subscriber-id field.                       The minimum length is 1 octet.      subscriber-id    The subscriber's identity.3.  DHCPv6 Relay Agent Behavior   DHCPv6 relay agents may be configured to include a Subscriber-ID   option in relayed (RELAY-FORW) DHCPv6 messages.  How the subscriber-   id is assigned and the mechanisms used to configure it are outside   the scope of this memo.4.  DHCPv6 Server Behavior   This option provides additional information to the DHCPv6 server.   The DHCPv6 server may use this information, if available, in addition   to other relay agent option data, other options included in the   DHCPv6 client messages, and physical network topology information in   order to assign IP addresses, delegate prefixes, and/or other   configuration parameters to the client.  There is no special   additional processing for this option.   There is no requirement that a server return this option and its data   in a RELAY-REPLY message.Volz                        Standards Track                     [Page 3]

RFC 4580               Relay Agent Subscriber-ID               June 20065.  Security Considerations   As the subscriber-id option is only exchanged between relay agents   and DHCPv6 servers, [1], Section 21.1, provides details on securing   DHCPv6 messages sent between servers and relay agents.  [1],Section23, provides general DHCPv6 security considerations.6.  IANA Considerations   IANA has assigned a DHCPv6 option code (38) for the Relay Agent   Subscriber-ID Option.7.  Acknowledgements   Thanks to Richard Johnson, Theyn Palaniappan, and Mark Stapp as this   document is essentially an edited version of their memo [3].8.  References8.1.  Normative References   [1]  Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M.        Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)",RFC 3315, July 2003.8.2.  Informative References   [2]  Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic Host        Configuration Protocol (DHCP) version 6",RFC 3633, December        2003.   [3]  Johnson, R., Palaniappan, T., and M. Stapp, "Subscriber-ID        Suboption for the Dynamic Host Configuration Protocol (DHCP)        Relay Agent Option",RFC 3993, March 2005.   [4]  Postel, J. and J. Reynolds, "Telnet Protocol Specification", STD        8,RFC 854, May 1983.   [5]  Droms, R., "Dynamic Host Configuration Protocol",RFC 2131,        March 1997.Volz                        Standards Track                     [Page 4]

RFC 4580               Relay Agent Subscriber-ID               June 2006Author's Address   Bernard Volz   Cisco Systems, Inc.   1414 Massachusetts Ave.   Boxborough, MA  01719   USA   Phone: +1 978 936 0382   EMail: volz@cisco.comVolz                        Standards Track                     [Page 5]

RFC 4580               Relay Agent Subscriber-ID               June 2006Full Copyright Statement   Copyright (C) The Internet Society (2006).   This document is subject to the rights, licenses and restrictions   contained inBCP 78, and except as set forth therein, the authors   retain all their rights.   This document and the information contained herein are provided on an   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET   ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,   INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE   INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.Intellectual Property   The IETF takes no position regarding the validity or scope of any   Intellectual Property Rights or other rights that might be claimed to   pertain to the implementation or use of the technology described in   this document or the extent to which any license under such rights   might or might not be available; nor does it represent that it has   made any independent effort to identify any such rights.  Information   on the procedures with respect to rights in RFC documents can be   found inBCP 78 andBCP 79.   Copies of IPR disclosures made to the IETF Secretariat and any   assurances of licenses to be made available, or the result of an   attempt made to obtain a general license or permission for the use of   such proprietary rights by implementers or users of this   specification can be obtained from the IETF on-line IPR repository athttp://www.ietf.org/ipr.   The IETF invites any interested party to bring to its attention any   copyrights, patents or patent applications, or other proprietary   rights that may cover technology that may be required to implement   this standard.  Please address the information to the IETF at   ietf-ipr@ietf.org.Acknowledgement   Funding for the RFC Editor function is provided by the IETF   Administrative Support Activity (IASA).Volz                        Standards Track                     [Page 6]