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Versions: (draft-doi-roll-mpl-parameter-configuration) 00 01 02 03 04 05 06 07 08 RFC 7774

roll                                                              Y. Doi
Internet-Draft                                       TOSHIBA Corporation
Intended status: Standards Track                             M. Gillmore
Expires: January 22, 2015                                     Itron, Inc
                                                           July 21, 2014


             MPL Parameter Configuration Option for DHCPv6
             draft-ietf-roll-mpl-parameter-configuration-02

Abstract

   This draft defines a way to configure a parameter set of MPL
   (Multicast Protocol for Low power and Lossy Networks) via DHCPv6
   option.  MPL has a set of parameters to control its behavior, and the
   parameter set is often configured as a network-wide parameter because
   the parameter set should be identical for each MPL forwarder in an
   MPL domain.  Using the MPL Parameter Configuration Option defined in
   this document, a network can be configured with a single set of MPL
   parameter easily.

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 January 22, 2015.

Copyright Notice

   Copyright (c) 2014 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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  MPL Parameter Configuration Option  . . . . . . . . . . . . .   3
     2.1.  MPL Parameter Configuration Option Format . . . . . . . .   3
     2.2.  DHCPv6 Client Behavior  . . . . . . . . . . . . . . . . .   5
     2.3.  MPL Forwarder Behavior  . . . . . . . . . . . . . . . . .   5
     2.4.  DHCPv6 Server Behavior  . . . . . . . . . . . . . . . . .   6
     2.5.  DHCPv6 Relay Behavior . . . . . . . . . . . . . . . . . .   6
     2.6.  Operational Considerations  . . . . . . . . . . . . . . .   6
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     5.2.  Non-Normative References  . . . . . . . . . . . . . . . .   7
   Appendix A.  Update History . . . . . . . . . . . . . . . . . . .   8
   Appendix B.  Considerations on Inconsistent Parameter Set . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   Multicast Protocol for Low power and Lossy Networks (MPL)
   [I-D.ietf-roll-trickle-mcast] defines a protocol to make a multicast
   network among low power and lossy network e.g. wireless mesh
   networks.  MPL has a set of parameters to control an MPL domain.  The
   parameter controls trade-off between end-to-end delay and network
   utilization.  In most environments, the default parameters are
   acceptable.  However, in some environments, the parameter set must be
   configured carefully in order to meet the requirements of each
   environment.  According to the MPL draft section 5.4, each parameter
   in the set should be same for all nodes within an MPL domain.  And
   the MPL draft does not define a method to configure the MPL parameter
   set.

   Some managed wireless mesh networks may have a DHCP server to
   configure network parameters.  MPL parameter set shall be considered
   as a part of network parameters (nodes in an MPL domain should use an
   identical parameter set).  And a parameter set are required to
   configure an MPL domain.

   This document is to define the way to distribute parameter sets for
   MPL forwarders as a DHCPv6 [RFC3315] option.  This document is
   intended to follow the guideline [RFC7227].



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2.  MPL Parameter Configuration Option

   Per MPL domain, there are following 10 parameters.  An MPL domain is
   defined by an MPL domain address.

   o  PROACTIVE_FORWARDING

   o  SEED_SET_ENTRY_LIFETIME

   o  DATA_MESSAGE_IMIN

   o  DATA_MESSAGE_IMAX

   o  DATA_MESSAGE_K

   o  DATA_MESSAGE_TIMER_EXPIRATIONS

   o  CONTROL_MESSAGE_IMIN

   o  CONTROL_MESSAGE_IMAX

   o  CONTROL_MESSAGE_K

   o  CONTROL_MESSAGE_TIMER_EXPIRATIONS

   One network may have multiple MPL domains with different
   configurations.  To configure more than one MPL domain via DHCP,
   there may be more than one MPL Parameter Configuration Option given
   to DHCP clients from a DHCP server.

2.1.  MPL Parameter Configuration Option Format

   To distribute a configuration of an MPL domain or a default value for
   all MPL domains (wildcard) under the network managed by the DHCP
   server, this document defines a DHCPv6 option format as follows.
   Short floating point format is used to describe wide range of timer
   values.

    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_MPL_PARAMETERS      |          option_len           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |P|     Z       |     TUNIT     |            SE_LIFETIME        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    DM_K       |         DM_IMIN               |       DM_IMAX >
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   > (cont'ed)     |         DM_T_EXP              |      C_K      |



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   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          C_IMIN               |          C_IMAX               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          C_T_EXP              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   (if option_len = 34 )
                                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                   |  MPL Domain Address           >
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   >          MPL Domain Address  (128bits)                        >
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   >          (cont'ed)                                            >
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   >          (cont'ed)                                            >
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   >          (cont'ed)            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   OPTION_MPL_PARAMETERS:  DHCPv6 option identifier (not yet assigned).

   option_len:  Length of the option.  It SHOULD be 18 (without MPL
      domain address) or 34 (with MPL domain address)

   P (1 bit):  A flag to indicate PROACTIVE_FORWARDING

   Z (7 bits)  Reserved.  Should be 0.

   TUNIT (unsigned 8 bit integer)  Unit time of times in this option.
      It SHALL NOT be 0 or 255.

   SE_LIFETIME:  SEED_SET_ENTRY_LIFETIME/TUNIT in milliseconds.  It
      SHALL NOT be 0 or 0xffff.

   DM_K (unsigned 8 bit integer):  DATA_MESSAGE_K.

   DM_IMIN (unsigned 16 bit integer):  DATA_MESSAGE_IMIN/TUNIT in
      milliseconds.  It SHALL NOT be 0 or 0xffff.

   DM_IMAX (unsigned 16 bit integer):  DATA_MESSAGE_IMAX/TUNIT in
      milliseconds.  It SHALL NOT be 0 or 0xffff.

   DM_T_EXP (unsigned 16 bit integer):  DATA_MESSAGE_TIMER_EXPIRATIONS/
      TUNIT in milliseconds.  It SHALL NOT be 0 or 0xffff.

   C_K (unsigned 8 bit integer):  CONTROL_MESSAGE_K.





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   C_IMIN (unsigned 16 bit integer):  CONTROL_MESSAGE_IMIN/TUNIT in
      milliseconds.  It SHALL NOT be 0 or 0xffff.

   C_IMAX:  CONTROL_MESSAGE_IMAX/TUNIT in milliseconds.  It SHALL NOT be
      0 or 0xffff.

   C_T_EXP:  CONTROL_MESSAGE_TIMER_EXPIRATIONS/TUNIT in milliseconds.
      It SHALL NOT be 0 or 0xffff.

   Note that all time values (Trickle timers and expiration periods) are
   in TUNIT milliseconds precision.  For example, if TUNIT is 20 and the
   data message interval minimum (DATA_MESSAGE_IMIN) is 1000ms, then
   DM_IMIN shall be set to 50.

2.2.  DHCPv6 Client Behavior

   Clients MAY request MPL Parameter Configuration Option, as described
   in RFC3315 [RFC3315], sections 17.1.1, 18.1.1, 18.1.3, 18.1.4, 18.1.5
   and 22.7.  As a convenience to the reader, we mention here that the
   client includes requested option codes in Option Request Option.

   Clients MUST discard MPL Parameter Configuration Option if it is
   invalid (e.g. it sets reserved bits or it has timers with reserved
   exp=7 in Unsigned Short Floating Point).

2.3.  MPL Forwarder Behavior

   If a DHCPv6 client requests and receives MPL Parameter Configuration
   Option, the node MAY join the MPL domain given by the option and act
   as an MPL forwarder.  Each joining node SHOULD configure its MPL
   forwarder with the given parameter set for the MPL domain.

   The priority of MPL Parameter Configuration applied for an MPL Domain
   is as follows (high to low).

   o  Specific MPL Parameter Configuration to the MPL Domain (optlen=34)

   o  Wildcard MPL Parameter Configuration (optlen=18)

   o  Default configuration given in the MPL specification.

   There SHALL be no more than one MPL Parameter Configuration Option
   for a MPL domain or the wildcard.  Thus, the order of DHCPv6 options
   in the packet has no effect on precedence.

   A node MAY leave from an MPL domain if the following two conditions
   are satisfied. 1) The MPL domain is configured by a DHCPv6 option
   from a DHCPv6 server previously. 2) The node has received an updated



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   MPL Parameter Configuration Option without a configuration for the
   MPL domain.

   MPL parameter may be updated occasionally.  With stateful DHCPv6,
   updates can be done when the renewal timer expires.  Information
   Refresh Time Option [RFC4242] shall be used to keep each forwarders
   updated.

   To reduce periodical update traffic a node may try to use very long
   interval between updates.  In the case, reconfigure shall be used to
   keep forwarder parameter sets synchronized.  For stateless DHCPv6,
   [I-D.jiang-dhc-stateless-reconfiguration] may be used (if approved).

2.4.  DHCPv6 Server Behavior

   Sections 17.2.2 and 18.2 of RFC3315 [RFC3315] govern server operation
   in regards to option assignment.  As a convenience to the reader, we
   mention here that the server will send MPL Parameter Configuration
   Option only if configured with specific value for MPL Parameter
   Configuration Option and the client requested it.

   Servers SHALL ignore incoming MPL Parameter Configuration Option.

2.5.  DHCPv6 Relay Behavior

   It's never appropriate for a relay agent to add options to a message
   heading toward the client, and relay agents don't actually construct
   Relay-Reply messages anyway.  There are no additional requirements
   for relays.

2.6.  Operational Considerations

   A parameter set for an MPL domain SHOULD NOT be updated more often
   than two times of expected refresh interval.

   If a node with MPL forwarder configured by MPL Parameter
   configuration Option failed to refresh the option for two times of
   information refresh time, it SHALL suspend the MPL forwarders of MPL
   domains configured by the option.  MPL forwarders configured by other
   methods such as static configuration file SHALL NOT be suspended.

3.  IANA Considerations

   A DHCPv6 option code for MPL Parameter Configuration Option needs to
   be assigned from IANA.

4.  Security Considerations




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   A forged option may cause excessive layer-2 broadcasting.
   Implementations should set reasonable bounds for each parameter.  For
   example, not too high K, not too low IMIN, etc.  These may be
   implementation dependent or may be derived from MAC/PHY
   specifications.  DHCP server or the network itself shall be trusted
   by some means including network access control or DHCP
   authentications.

5.  References

5.1.  Normative References

   [I-D.ietf-roll-trickle-mcast]
              Hui, J. and R. Kelsey, "Multicast Forwarding Using
              Trickle", draft-ietf-roll-trickle-mcast-07 (work in
              progress), Feburary 2014.

   [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.

   [RFC4242]  Venaas, S., Chown, T., and B. Volz, "Information Refresh
              Time Option for Dynamic Host Configuration Protocol for
              IPv6 (DHCPv6)", RFC 4242, November 2005.

5.2.  Non-Normative References

   [I-D.ietf-dhc-option-guidelines]
              Hankins, D., Mrugalski, T., Siodelski, M., Jiang, S., and
              S. Krishnan, "Guidelines for Creating New DHCPv6 Options",
              draft-ietf-dhc-option-guidelines-17 (work in progress),
              January 2014.

   [I-D.jiang-dhc-stateless-reconfiguration]
              Jiang, S. and B. Liu, "Stateless Reconfiguration in
              Dynamic Host Configuration Protocol for IPv6 (DHCPv6)",
              draft-jiang-dhc-stateless-reconfiguration-01 (work in
              progress), February 2014.

   [RFC7227]  Hankins, D., Mrugalski, T., Siodelski, M., Jiang, S., and
              S. Krishnan, "Guidelines for Creating New DHCPv6 Options",
              BCP 187, RFC 7227, May 2014.









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Appendix A.  Update History

   Updates on draft-ietf-roll-mpl-configuration-01 to draft-ietf-roll-
   mpl-configuration-02:

   o  Short unsigned floating point is dropped (#159)

   o  Packed value is removed and now every value has its own byte(s)
      (#159)

   Updates on draft-ietf-roll-mpl-configuration-00 to draft-ietf-roll-
   mpl-configuration-01:

   o  Operational considerations (normative) and appendix considerations
      (non-normative) are added (Issue #157)

   o  More control on nodes / allow constrained nodes to ignore the
      configuration: "the node s/SHOULD/MAY/ join the MPL domain given
      by the option" (Issue #158)

   Updates on draft-doi-roll-mpl-configuration-05 to draft-ietf-roll-
   mpl-configuration-00:

   o  I-D renamed.

Appendix B.  Considerations on Inconsistent Parameter Set

   This draft introduces dynamic update of MPL parameters.  Because the
   update process is not synchronized, nodes may have inconsistent
   parameter set.

   Inconsistent parameter may reduce performance.  On the other hand, it
   shall work as long as both parameter set are reasonable parameter set
   for a given communication load.  As motivations for parameter update
   are update on environment, node density, or communication load,
   operators of MPL networks shall be aware of unupdated nodes and make
   sure old and new parameter sets are reasonable for expected refresh
   intervals.

Authors' Addresses











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   Yusuke Doi
   TOSHIBA Corporation
   Komukai Toshiba Cho 1
   Saiwai-Ku
   Kawasaki, Kanagawa  2128582
   JAPAN

   Phone: +81-45-342-7230
   Email: yusuke.doi@toshiba.co.jp


   Matthew Gillmore
   Itron, Inc
   2111 N Molter Rd.
   Liberty Lake, WA  99019
   USA

   Email: matthew.gillmore@itron.com

































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