DHC Working Group                                                 R. Yan
Internet Draft                                                  Y. Jiang
Expiration Date: May 2007                          Alcatel Shanghai Bell
                                                                 X. Duan
                                                            China Mobile





                     Domain Suffix Option for DHCPv6
              <draft-ietf-dhc-dhcpv6-opt-dnsdomain-04.txt>

                         November 10, 2006


Status of this Memo

   By submitting this Internet-Draft, each author represents that any
   applicable patent or other IPR claims of which he or she is aware
   have been or will be disclosed, and any of which he or she becomes
   aware will be disclosed, in accordance with Section 6 of 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 May 6, 2007.

Copyright Notice

   Copyright (C) The Internet Society (2006).

Abstract

    This document describes a new option for DHCPv6 (DHCP for IPv6) that
    provides a mechanism for specifying a domain name suffix.




Yan, et. al.                                                    [Page 1]


Internet-Draft     domain suffix option for DHCPv6         November 2006


1.  Introduction

   This document describes a new option for DHCPv6 [RFC3315] that
   provides a mechanism for specifying a domain name suffix. Using this
   option, the DHCPv6 server can specify a domain name suffix to the
   DHCPv6 client.

1.1  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].

   Domain suffix
                 In this document, the domain suffix is defined as the
                 suffix of a fully qualified domain name (FQDN). It is
                 starts with lower-level domain name and continues all
                 the way up to the top-level domain name.

   This document should be read in conjunction with the DHCPv6
   specification, [RFC3315]. Definitions for terms and acronyms used in
   this document are defined in RFC3315.


2.  Domain Suffix Option

   The domain suffix option for DHCPv6 is used by the DHCPv6 server to
   tell the DHCPv6 client the domain suffix that the DHCPv6 server
   administrator has specified for that DHCPv6 client.

   The format of the domain suffix option is:

     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-code          |         option-length         |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                               |
    ~                          domain suffix                        ~
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   option-code:     OPTION_DOMAIN_SUFFIX (TBD).

   option-length:   length of the "domain suffix" field in octets.

   domain suffix:   the specification of a domain suffix.




Yan, et. al.                                                    [Page 2]


Internet-Draft     domain suffix option for DHCPv6         November 2006


   The domain suffix in the 'domain suffix' field MUST be encoded as
   specified in section of RFC3315 titled "Representation and use of
   domain names", except that it SHOULD only include one domain name,
   being a series of labels terminated by exactly one root label.

   If more than one root label is present, the DHCP client
   implementations MUST select the first name, ignoring any subsequent
   labels.

2.1  Usage

   A DHCPv6 client MUST include the option code in Option Request
   Option [RFC3315] if it desires the domain suffix option, and the
   DHCPv6 server SHOULD include this option in an Advertise or Reply
   if requested by the client in the Option Request Option.

   A DHCPv6 server may provide different values for the domain suffix
   option to different clients.  The mechanism for choosing which
   suffix to assign to which client is a matter of implementation and
   administrative policy, and is therefore not specified in this
   document.


3.  Security Considerations

   Security considerations in DHCP are described in section 23,
   "Security Considerations" of RFC3315.


4.  IANA Considerations

   IANA is requested to assign a DHCPv6 option code for the
   OPTION_DOMAIN_SUFFIX.


5.  Acknowledgements

   The authors thank Ralph Droms, Ted Lemon, Stig Venaas, Bernie Volz,
   Tatuya Jinmei, Joe Quanaim and Stefaan De Cnodder for valuable
   discussions and comments.


6.  References

6.1 Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.



Yan, et. al.                                                    [Page 3]


Internet-Draft     domain suffix option for DHCPv6         November 2006


   [RFC3315]  Bound, J., Carney, M., Perkins, C., Lemon, T., Volz, B.
              and R. Droms (ed.), "Dynamic Host Configuration Protocol
              for IPv6 (DHCPv6)", RFC 3315, May 2003.

   [RFC3633]  O. Troan, R. Droms, "IPv6 prefix option for DHCPv6",
              RFC3633, December 2003.



Appendix:  Examples

   The examples defined below are intended to give a reference usage of
   the domain suffix option.

   Example 1: Used for host

   One obvious example for the option is in a case where a DHCP client
   is not configured to assert a particular domain.  The client could
   request the domain suffix in the ORO option to request the domain
   name it could use, as the usage for option 15 in DHCPv4.


   Example 2: Used for IPv6 residential gateway

   In IPv6 home network, it is easy to imagine that each device can get
   a globally unique IPv6 address, so that the device could be visited
   from outside network easily.  It will be better if these devices
   could be accessed using domain name other than the tedious IPv6
   address.

   Usually, residential gateway in home network works as a prefix
   requesting router [RFC3633] to request IPv6 prefix from prefix
   delegation router and allocate the address to home device using
   stateless configuration or through an embedded DHCPv6 server.
   One method to configure the domain suffix in CPEs in large scale is
   using domain suffix option.

   During DHCP session initiated by residential gateway, domain suffix
   name (e.g. example.com) could be specified.

   The domain suffix can then be used to update domain name for the
   hosts in subscriber network, by an embedded DHCPv6 server in
   residencial gateway or by other means of DNS update mechanism for
   stateless IPv6 configuration.







Yan, et. al.                                                    [Page 4]


Internet-Draft     domain suffix option for DHCPv6         November 2006


   To avoid frequent domain name conflicts, aggregation device might
   allocate different domain suffix name for the CPE. An example way can
   be selection based on an external authority such as a RADIUS server,
   in which an unique domain suffix name prefix, called "home name", are
   negotiated between user and ISP when subscribing. For example,
   "user1.example.com" and "user2.example.com".













































Yan, et. al.                                                    [Page 5]


Internet-Draft     domain suffix option for DHCPv6         November 2006


Authors' Addresses

   Renxiang Yan
   Yinglan Jiang
   Research & Innovation Center
   Alcatel Shanghai Bell Co., Ltd.
   388#, NingQiao Road, Pudong Jinqiao,
   Shanghai 201206 P.R. China
   Phone: +86 (21) 5854-1240, ext. 7169

   Email: renxiang.yan@alcatel-sbell.com.cn
          Yinglan.jiang@alcatel-sbell.com.cn


   Xiaodong Duan
   Research & Development Center
   China Mobile Communications Corporation
   53A, Xibianmennei Ave., Xuanwu District,
   Beijing, 100053 P.R. China
   Phone: +86 (10) 6600-6688, ext. 3062

   Email: duanxiaodong@chinamobile.com





























Yan, et. al.                                                    [Page 6]


Internet-Draft     domain suffix option for DHCPv6         November 2006


Full Copyright Statement

   Copyright (C) The Internet Society (2006).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 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 in BCP 78 and BCP 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 at
   http://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.


Acknowledgment

   Funding for the RFC Editor function is currently provided by the
   Internet Society.






Yan, et. al.                                                    [Page 7]