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Versions: 00 01 02 03 04 05 draft-ietf-roll-mpl-parameter-configuration

Application                                                       Y. Doi
Internet-Draft                                       TOSHIBA Corporation
Intended status: Informational                              July 5, 2013
Expires: January 6, 2014


             MPL Parameter Configuration Option for DHCPv6
             draft-doi-roll-mpl-parameter-configuration-00

Abstract

   This draft is to define a way to configure MPL parameter via DHCPv6
   option.

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 January 6, 2014.

Copyright Notice

   Copyright (c) 2013 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
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   (http://trustee.ietf.org/license-info) in effect on the date of
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   described in the Simplified BSD License.






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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  MPL Parameter Configuration Option  . . . . . . . . . . . . . . 3
     2.1.  Unsigned Short Floating Point . . . . . . . . . . . . . . . 4
     2.2.  MPL Parameter Configuration Option Format . . . . . . . . . 4
   3.  Operation of MPL Forwarders . . . . . . . . . . . . . . . . . . 6
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 7
   6.  Normative References  . . . . . . . . . . . . . . . . . . . . . 7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 7








































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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 i.e. wireless mesh
   networks.  MPL has various parameters to control its behavior and
   tradeoff between end-to-end delay and network utilization.  In some
   environments, the parameters shall be configured carefully to meet
   each environment and requirement.  According to the MPL draft section
   5.4, the parameter should be same for all nodes within an MPL domain.
   And the MPL draft does not define a method to configure it.

   Some managed wireless mesh networks may have a DHCP server to
   configure network parameters with DHCP relay in each node.  MPL
   parameters shall be considered as a part of network parameters
   (parameter shall match within an MPL domain).  This document is to
   define the way to distribute parameters for MPL forwarders via DHCPv6
   [RFC3315] options.


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
   configuration.  To configure plural of MPL domains via DHCP, there
   may be more than one MPL Parameter Configuration Option given to DHCP



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   clients from a DHCP server.

2.1.  Unsigned Short Floating Point

   MPL has many timer parameters.  Expected range of the timers depends
   on the network topology or MAC/PHY nature.  To accomodate wide range
   of timer values efficiently, the MPL Parameter Configuration Option
   uses base-10 unsigned short floating point number with 3-bit exponent
   and 13-bit significand defined as follows (exp. stands for exponent).

    0                   1
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | exp.|      significand        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The represented value is (significand) * 10^(exp.).  Minimum exponent
   is 0 (binary 000) and maximum is 6 (binary 110). exp=7 (binary 111)
   is reserved for future use.  Minimum significand is 0 (all 0) and
   maximum is 8191 (all 1).

   Unlike IEEE754 half precision floating point (binary16), there is no
   sign bit (no negative value for a timer), exponent is not biased (no
   fractional value for a timer), no implicit leading 1 in siginificand,
   and base is 10.  Therefore, there could be more than one
   representations for a value.

   Followings are examples of common timer values represented by unit of
   milliseconds.

   One second (1,000 ms.):  exp = 3, significand = 1. 0x6001.

   One minute (60,000 ms.):  exp = 4, significand = 6, 0x8006.

   One hour (3,600,000 ms.):  exp = 5, significand = 36, 0xa024.

   One day (86,400,000 ms.):  exp = 5, significand = 864, 0xa360

   Maximum timer length represented by unsigned short floating point
   with millisecond precision is 8191*10^6 milliseconds (13 weeks 3 days
   19 hours 16 minutes 40 seconds).

2.2.  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



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   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|C|Z|   C_K   | Z2  |  DM_K   |         SE_LIFETIME           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         DM_IMIN               |          DM_IMAX              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         DM_T_EXP              |          C_IMIN               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         C_IMAX                |          C_T_EXP              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   (if C = 1)
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          MPL Domain Address  (128bits)                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          (cont'ed)                                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          (cont'ed)                                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          (cont'ed)                                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   OPTION_MPL_PARAMETERS:  not yet assigned.

   option_len:  Length of the option

   P (1 bit):  A flag to indicate PROACTIVE_FORWARDING

   C (1 bit):  MPL configuration type.

   Z (1 bit)  Reserved.  Should be 0.

   C_K (5 bits):  Value of CONTROL_MESSAGE_K.

   Z2 (3 bit)  Reserved.  Should be all 0.

   DM_K (5 bits):  Value of DATA_MESSAGE_K.

   SE_LIFETIME:  SEED_SET_ENTRY_LIFETIME.  The value is milliseconds in
      unsigned short floating point.






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   DM_IMIN:  Value of DATA_MESSAGE_IMIN.  The value is milliseconds in
      unsigned short floating point.

   DM_IMAX:  Value of DATA_MESSAGE_IMAX.  The value is milliseconds in
      unsigned short floating point.

   DM_T_EXP:  Value of DATA_MESSAGE_TIMER_EXPIRATIONS.  The value is
      milliseconds in unsigned short floating point.

   C_IMIN:  Value of CONTROL_MESSAGE_IMIN.  The value is milliseconds in
      unsigned short floating point.

   C_IMAX:  Value of CONTROL_MESSAGE_IMAX.  The value is milliseconds in
      unsigned short floating point.

   C_T_EXP:  Value of CONTROL_MESSAGE_TIMER_EXPIRATIONS.  The value is
      milliseconds in unsigned short floating point.

   'C' defines configuration target type.

   o  '0' : Wildcard configuration.  Only zero or one wildcard
      configuration SHALL exist in a configuration set.  Wildcard
      configuration MUST NOT have a MPL domain address.

   o  '1' : Specific configuration for an MPL domain.  The configuration
      SHALL have (uncompressed) IPv6 multicast address as MPL Domain
      Address.


3.  Operation of MPL Forwarders

   The node SHOULD join the MPL domain given and act as an MPL
   Forwarder.  Nodes SHOULD configure MPL forwarders when it joins to
   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 (C=1)

   o  Wildcard MPL Parameter Configuration (C=0)

   o  Default configuration given in the MPL specification.








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4.  IANA Considerations

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


5.  Security Considerations

   Forged option may cause too many MAC broadcasting.  Reasonable bound
   of parameters (not too high K, not too low IMIN) may be defined by
   implementations or derived from MAC/PHY specifications.  DHCP server
   or the network itself shall be trusted by some means including
   network access control or DHCP authentications.


6.  Normative References

   [I-D.ietf-roll-trickle-mcast]
              Hui, J. and R. Kelsey, "Multicast Forwarding Using
              Trickle", draft-ietf-roll-trickle-mcast-04 (work in
              progress), Feburary 2013.

   [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.


Author's Address

   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
   URI:












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