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Versions: 00 01 draft-ietf-dhc-triggered-reconfigure

Network Working Group                                       M. Boucadair
Internet-Draft                                            France Telecom
Updates: 3315 (if approved)                              August 24, 2012
Intended status: Standards Track
Expires: February 25, 2013


              RECONFIGURE Triggered by DHCPv6 Relay Agents
              draft-boucadair-dhc-triggered-reconfigure-00

Abstract

   This document specifies a companion solution to the RSOO (Relay-
   Supplied Options option) procedure to trigger a DHCPv6 server to
   issue a RECONFIGURE message.  This document defines a new DHCPv6
   messages type: RECONFIGURE-REQUEST.  This message is issued by a
   relay agent to notify a DHCPv6 server a change has occurred in the
   configuration supplied in an RSOO.

   This document updates RFC 3315.

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
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   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 February 25, 2013.

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



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   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.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
     1.1.  Problem . . . . . . . . . . . . . . . . . . . . . . . . . . 3
     1.2.  Requirements Language . . . . . . . . . . . . . . . . . . . 4
   2.  Proposed Solution . . . . . . . . . . . . . . . . . . . . . . . 4
   3.  RECONFIGURE-REQUEST . . . . . . . . . . . . . . . . . . . . . . 5
     3.1.  Message Format  . . . . . . . . . . . . . . . . . . . . . . 5
     3.2.  Message Validation  . . . . . . . . . . . . . . . . . . . . 5
     3.3.  Creation and Transmission of RECONFIGURE-REQUEST  . . . . . 6
     3.4.  Server Behaviour  . . . . . . . . . . . . . . . . . . . . . 6
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 6
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 6
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     7.1.  Normative References  . . . . . . . . . . . . . . . . . . . 7
     7.2.  Informative References  . . . . . . . . . . . . . . . . . . 7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 7



























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1.  Introduction

1.1.  Problem

   [RFC6422] updates DHCPv6 specification [RFC3315] with a new feature
   to let a DHCPv6 relay agent communicate information not available at
   the DHCPv6 server to a DHCPv6 client.  This is achieved owing to the
   use of RSOO (Relay-Supplied Options option) which carries
   configuration data to the DHCPv6 server.  The data conveyed in an
   RSOO is then sent back by the DHCPv6 server to the requesting DHCPv6
   client.

   An illustration example is shown in Figure 1; only a subset of
   exchanged messages are represented.

      +-------+                   +-------+                    +-------+
      |DHCPv6 |                   |  NAS  |                    |Radius |
      |Client |                   |(DHCPv6|                    |Server |
      |       |                   | Relay)|                    |       |
      +-------+                   +-------+                    +-------+
          |                           |                            |
          |---Solicit---------------->|                            |
                                      |---Access-Request---------->|
                                      |<--Access-Accept------------|
                                      |   (e.g. AFTR_NAME)
                                    ....

                                      |                        +-------+
                                      |                        |DHCPv6 |
                                      |                        |Server |
                                      |                        |       |
                                      |                        +-------+
                                      |---Relay-Forward----------->|
                                      |   (RSOO(AFTR_NAME))
                                      |
                                      |<--Relay-Reply--------------|
          |<--Advertise---------------|
              (e.g., AFTR_NAME)       |
                                     ....


                        Figure 1: RSOO Flow Example

   The change of the configuration may result in RADIUS exchanges
   between the NAS/DHCPv6 relay agent and AAA server as shown in
   Figure 2.  Note the change of the configuration in the DHCPv6 relay
   agent can be triggered by any other out-of-band mechanism.




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      +-------+                   +-------+                    +-------+
      |DHCPv6 |                   |  NAS  |                    |Radius |
      |Client |                   |(DHCPv6|                    |Server |
      |       |                   | Relay)|                    |       |
      +-------+                   +-------+                    +-------+
          |                           |                            |
                                      |<-----CoA-Request-----------|
                                      |   (e.g. AFTR_NAME)
                                      |------CoA-Response--------->|
                                    ....


                     Figure 2: Change of configuration

   In the event of the change of the configuration data supplied to the
   DHCPv6 server by the DHCPv6 relay agent, DHCPv6 server has no trigger
   to issue a Reconfigure message with the updated configuration data.
   A solution is sketched in Section 2.

1.2.  Requirements Language

   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].


2.  Proposed Solution

   To solve the problem described in Section 1.1, this document proposes
   a new DHCP message called Reconfigure-Request.  This message is sent
   by the DHCPv6 relay agent to a DHCPv6 server when a configuration
   data already supplied in an RSOO is detected.  In particular,
   Reconfigure-Request must include RSOO with the new configuration.
   Upon receipt of this message, and if it is configured to support such
   mode, the DHCPv6 server must build a Reconfigure message which copies
   the data conveyed in RSOO.  This message is sent to the DHCPv6 relay
   and then relayed to the appropriate DHCPv6 client.

   This setup assumes the relay has a record of the client, so it has
   enough information to send the request to the server.  Means to
   recover state in failure events must be supported.

   An example is depicted in Figure 3.








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      +-------+                   +-------+                    +-------+
      |DHCPv6 |                   |  NAS  |                    |Radius |
      |Client |                   |(DHCPv6|                    |Server |
      |       |                   | Relay)|                    |       |
      +-------+                   +-------+                    +-------+
          |                           |                            |
                                      |<-----CoA-Request-----------|
                                      |   (e.g. AFTR_NAME)
                                      |------CoA-Response--------->|
                                    ....
                                      |                        +-------+
                                      |                        |DHCPv6 |
                                      |                        |Server |
                                      |                        |       |
                                      |                        +-------+
                                      |---Reconfigure-Request----->|
                                      |   (RSOO(AFTR_NAME))
                                      |
                                      |<--Relay-Reply -------------|
          |<--Reconfigure-------------|   (Reconfigure(AFTR_NAME))
              (e.g., AFTR_NAME)       |
                                    ....

                Figure 3: RECONFIGURE-REQUEST Flow Example


3.  RECONFIGURE-REQUEST

3.1.  Message Format

   The RECONFIGURE-REQUEST message uses the Client/Server message format
   described in Section 6 of [RFC3315].  A new message type code is
   defined

      RECONFIGURE-REQUEST (To be assigned by IANA, see Section 4).

3.2.  Message Validation

   Clients MUST discard any received RECONFIGURE-REQUEST messages.

   Servers MUST discard any received RECONFIGURE-REQUEST messages that
   meet any of the following conditions:

   o  the message does not include an OPTION_CLIENTID option.
   o  the message includes an OPTION_SERVERID option but the contents of
      the OPTION_SERVERID option does not match the server's identifier.
   o  the message does not include an RSOO.




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   Server MUST be configurable to accept or reject RECONFIGURE-REQUEST
   messages.  If the server is configured to reject RECONFIGURE-REQUEST,
   any received RECONFIGURE-REQUEST is silently dropped.

3.3.  Creation and Transmission of RECONFIGURE-REQUEST

   In the event of change of an information which has been supplied to
   the DHCPv6 server, the relay agent determines the client which is
   concerned by the change and then builds a Reconfigure-Request
   message: the relay agent sets the "msg-type" field to RECONFIFURE-
   REQUEST and sets the "transaction-id" field to 0.  The relay agent
   MUST supply the updated configuration in RSOO as defined in [RFC6422]
   and MUST include an OPTION_CLIENTID option [RFC3315] to identify the
   client to the DHCPv6 server.

3.4.  Server Behaviour

   Upon receipt of a valid Reconfigure-Request message from a DHCPv6
   relay agent, the server follows the procedure defined in Section 19.1
   of [RFC3315] and Section 4 of [RFC6422] to construct a Reconfigure
   message.

   As defined in [RFC3315], this message may be sent directly to the
   DHCPv6 client or to a relay agent.


4.  IANA Considerations

   This document requests IANA to assign a new DHCPv6 Message type:

      RECONFIGURE-REQUEST


5.  Security Considerations

   Security considerations elaborated in [RFC3315] and [RFC6422] must be
   taken into account.

   Some security issues discussed in [RFC5007] may also be valid for
   RECONFIGURE-REQUEST.  This will be elaborated in further versions of
   this document.


6.  Acknowledgements

   Many thanks to T. Lemon for the discussion prior to the publication
   of this document.




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7.  References

7.1.  Normative References

   [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.

   [RFC6422]  Lemon, T. and Q. Wu, "Relay-Supplied DHCP Options",
              RFC 6422, December 2011.

7.2.  Informative References

   [RFC5007]  Brzozowski, J., Kinnear, K., Volz, B., and S. Zeng,
              "DHCPv6 Leasequery", RFC 5007, September 2007.


Author's Address

   Mohamed Boucadair
   France Telecom
   Rennes,   35000
   France

   Email: mohamed.boucadair@orange.com























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