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Network Working Group                                        B. Sarikaya
Internet-Draft                                                    F. Xia
Intended status: Standards Track                              Huawei USA
Expires: January 2, 2011                                        P. Seite
                                                          France Telecom
                                                            July 1, 2010


    DHCPv6 Extension for Configuring Hosts with Multiple Interfaces
                draft-sarikaya-mif-dhcpv6solution-04.txt

Abstract

   This document defines DHCPv6 Options to configure a multi-homed
   host's routing table with new entries when the host attaches to a new
   network on a new interface.

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 2, 2011.

Copyright Notice

   Copyright (c) 2010 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
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   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.



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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Configuring Routing Tables of Multi-homed Hosts  . . . . . . .  3
   4.  DHCPv6 Option  . . . . . . . . . . . . . . . . . . . . . . . .  4
     4.1.  Option Format  . . . . . . . . . . . . . . . . . . . . . .  4
     4.2.  Flow Description Sub-option  . . . . . . . . . . . . . . .  6
     4.3.  QoS Info Sub-option  . . . . . . . . . . . . . . . . . . .  6
     4.4.  Flow Route Prefix Sub-option . . . . . . . . . . . . . . .  7
     4.5.  IPv6 Router Address Sub-option . . . . . . . . . . . . . .  8
     4.6.  Interface Info Sub-option  . . . . . . . . . . . . . . . .  9
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . .  9
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 10
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 10
     8.2.  Informative references . . . . . . . . . . . . . . . . . . 11
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12
































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1.  Introduction

   Traditional routing considered only the destination address in
   IPv4/v6 header.  Policy-based routing on the hand considers other
   fields in the header sometimes even the payload.  In IPv6, the hosts
   receive router advertisements (RA) containing information useful for
   enforcing policy-based routing.  However in some networks, e.g.
   cellular networks, DHCP servers can be used to help multi-homed
   mobile nodes configure their routing tables.

   Using a single default route would lead to routing of all flows
   through a single interface.  Such a configuration makes it impossible
   to use multiple interfaces simultaneously if the host is multi-homed.

   Requirements of supporting multiple interfaces in hosts without
   involving mobility protocols are discussed in
   [I-D.ietf-mif-problem-statement], [I-D.yang-mif-req].  DHCP is
   identified as a protocol to communicate interface management policies
   between MIF nodes and the network.

   The IPv6 hosts receive router advertisements and then populate their
   Default Router List and Prefix List based on information in the
   router advertisements [RFC2461].  [RFC4191] extended RAs with Route
   Information Option and added Default Router Preference.  Such RAs if
   available would help multi-homed mobile nodes configure better to
   enable the simultaneous use of all interfaces.

   In this document we define a new DHCPv6 [RFC3315] Option.  This
   option is to inform multi-homed hosts about the routes and other
   useful information available on the new network that the host has
   just connected.  It is appropriate to use DHCP for this purpose
   because DHCP is already needed for initial configuration of the
   host's interface, e.g. for address assignment.


2.  Terminology

   This document uses the terminology defined in [RFC3315] and
   [RFC3633].


3.  Configuring Routing Tables of Multi-homed Hosts

   An IPv6 routing table contains these entries (non exhaustive list):
   prefix, prefix length, preference value, lifetime, and the address of
   the next-hop router.

   Multi-homed hosts receive configuration information on each



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   interface.  Routers send router advertisements.  DHCP servers provide
   host configuration information.  SDOs are defining servers such as
   Access Network Discovery and Selection Function (ANDSF) [3GPP23402].
   ANDSF can also provide node configuration information on SDO
   interfaces.  Configuration information helps host set up and update
   important databases that the host uses such as the routing table.

   Since IPv6 allows multiple unicast addresses to be assigned to
   interfaces, IPv6 hosts face the problem of default source and
   destination address selection when initiating communication.
   [RFC3484] defines algorithms for this purpose.

   In this document we define a new DHCPv6 Option called multi-homed
   routing policy entry option.  Using this Option DHCPv6 server can
   inform DHCPv6 client on the default routes available on the interface
   which the host is about to connect.  The option also allows DHCP
   server to provide more information on the flows such as more
   sophisticated flow description.  The host receives the route
   information ordered with priority which allows the host to select the
   right interface to start communication.

   DHCP server gets information about host's interface using Interface
   Info Sub-option included in the multi-homed routing policy entry
   option.  A MIF host MAY include one Interface Info Sub-option for
   each of its interfaces.  A MIF host requesting routing information
   MAY set preferred-lifetime to a value in multi-homed routing policy
   entry option.  DHCP server considers preferred-lifetime value it
   received and it sets valid-lifetime value in the reply.  Valid-
   lifetime value defines the expiration value of the routing policy
   entry.

   Policy entries are identified using Policy Identifiers (PID).  Each
   option MUST have a unique PID.


4.  DHCPv6 Option

4.1.  Option Format

   A new option is defined to carry the host routing information.  It is
   shown in Figure 1.

   DHCP server MAY send a Reply message containing multi-homed routing
   policy entry option.  DHCP client MUST add an entry to its routing
   table based on this option.  DHCP client MAY modify other tables such
   as Default Router List or Pref List [RFC4191].

   DHCP Client MAY include multi-homed routing policy entry option in



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   Option Request Option [RFC3315] in DHCP Request message.  DHCP Server
   MUST include multi-homed routing policy entry option in the
   corresponding Reply message.  The option contains a list of routing
   policies, each of them containing the flow description followed by
   the route to apply when datagram to forward is matching.



        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_MHRPE           |         option-length         |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |         sub-option-code       |         sub-option-len        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                        sub-option-content                     |
       .                                                               .
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                             ...                               |
       .                                                               .
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                              ...                              |
       .                                                               .
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |  PID          |             Reserved                          |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                      preferred-lifetime                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                          valid-lifetime                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


            Figure 1: DHCPv6 Multi-Homed Routing Policy Option

   o  Option-code: OPTION_MHRPE multi-homed routing policy entry option
      (To be assigned by IANA)
   o  Option-length: Total length of the sub-options + 4.
   o  sub-option-code: the code of the included sub option.  In this
      document SUB_OPTION_FLOW_DESC, SUB_OPTION_QOS_INFO,
      SUB_OPTION_PREFIX and SUB_OPTION_ROUTER_ADDRESS are defined.
   o  sub-option-len: length of the sub-option.
   o  sub-option-content: content of the sub-option.
   o  PID: The Policy Identifier field is an 8-bit unsigned integer that
      includes the identifier for the policy.
   o  Reserved: 24 bits set to zero by the sender ignored by the
      receiver
   o  preferred-lifetime: The preferred lifetime in units of seconds for
      the multi-homed routing policy entry option.




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   o  valid lifetime: The valid lifetime in units of seconds for the
      multi-homed routing policy entry option.

4.2.  Flow Description Sub-option

   Flow Description Sub-option is used to describe the flow for this
   route.  More than one flow description MAY be included.  Flow
   descriptions are usually in binary format but textual formats are
   also allowed.  The preferred interface for this flow is included in
   Interface Info Sub-option.



        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    SUB_OPTION_FLOW_DESC       |         sub-option-len        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |   FD-Type   | FD-len          |                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
       |                   Flow Description ...                        |
       .                                                               .
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                   Figure 2: Flow Description Sub-option

   o  option-code: SUB_OPTION_FLOW_DESC (to be assigned by IANA)
   o  option-length: Variable.
   o  FD-Type: type of the flow description:
   o
      o (0) Reserved
      o (1) Binary
      o (2) Text
   o  FD-len: length of the flow description that follows in bytes.
   o  Flow Description: This field contains flow description in binary
      such as in [I-D.ietf-mext-binary-ts] or in textual format.  This
      field is of length FD-length.

4.3.  QoS Info Sub-option

   This Sub-option contains quality of service information associated
   with each interface as specified in Interface Info Sub-option, e.g.
   on 3G 150kbps for video on WiFi 400kbps for video.







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        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    SUB_OPTION_QOS_INFO        |         sub-option-len        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |QoS Information Code           |QoS Information Sub-Code       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |QoS Information value                                          |
       +                                                               +
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                         Figure 3: QoS Sub-option

   o  option-code: SUB_OPTION_QOS_INFO (to be assigned by IANA)
   o  option-length: Variable.
   o  QoS information Code: this field identifies the type of the QoS
      information:
   o
      o (0) Reserved
      o (1) Packet rate
      o (2) One-way delay metric
      o (3) Inter-packet delay variation
   o  QoS information Sub-code: this field carries the sub-type of the
      QoS information.  The following sub-types have been identified:
   o
      o  (0) None
      o  (1) Reserved rate
      o  (2) Available rate
      o  (3) Loss rate
      o  (4) Minimum one-way delay
      o  (5) Maximum one-way delay
      o  (6) Average one-way delay
   o  QoS information value: this field indicates the value of the QoS
      information.  The corresponding units depend on the instantiation
      of the QoS information code.

4.4.  Flow Route Prefix Sub-option

   This Sub-option defines IPv6 prefix over which the flow as defined in
   flow description sub-option will be routed.  One flow route prefix
   sub-option MAY be included for each flow description sub-option.









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        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    SUB_OPTION_FR_PREFIX       |         sub-option-len        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | prefix-len    |                                               |
       +-+-+-+-+-+-+-+-+          IPv6 prefix                          |
       |                           (variable)                          |
       |                                                               |
       ~                                                               ~
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                  Figure 4: Flow Route Prefix Sub-option

   o  option-code: SUB_OPTION_FR_PREFIX (to be assigned by IANA)
   o  option-length: Variable.
   o  prefix-len: Prefix length of the destination prefix over which the
      flow will be routed
   o  IPv6 prefix: Destination prefix over which the flow will be
      routed.  The first prefix-len bits make up the prefix.  The rest
      is ignored.

4.5.  IPv6 Router Address Sub-option

   This sub-option defines the default router address for this route.
   Flow Route Prefix Sub-option and IPv6 Router Address Sub-option
   define a route.

   For each flow there MUST be at least one route.  If more than one
   route is defined the first route is the primary route.


        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    SUB_OPTION_ROUTER_ADDRESS  |         sub-option-len        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                IPv6 Router Address (16 octets)                |
       |                                                               |
       |                                                               |
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | prefix-length |                 Reserved                      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                 Figure 5: IPv6 Router Address Sub-option




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   o  option-code: SUB_OPTION_ROUTER_ADDRESS (to be assigned by IANA)
   o  option-length: 24.
   o  IPv6 Router Address: Default router address for this route.  This
      field is 16 octets.
   o  Prefix-length: Length of the prefix of IPv6 router address field.
      It is 8 bits.
   o  Reserved: 24 bits set to zero by the sender ignored by the
      receiver

4.6.  Interface Info Sub-option

   Interface Info Sub-option is used to provide information about each
   interface of the host.  One such sub-option SHOULD be included for
   each interface of a MIF host.

   Link layer address is a MAC address for IEEE interfaces such as
   Ethernet or Wi-Fi.  Link layer address could be International Mobile
   Subscriber Identity (IMSI) for some 3G or 4G interfaces.


        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    SUB_OPTION_INTERFACE_INFO  |         sub-option-len        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |      ATT      |  Length       |                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
       |                           Link Layer Address                  |
       +                                                               +
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                    Figure 6: Interface Info Sub-option

   o  option-code: SUB_OPTION_INTERFACE_INFO (to be assigned by IANA)
   o  option-length: 16.
   o  ATT: This is an 8-bit field that specifies the access technology
      of the interface.  The values for this field are assigned from
      Access Technology Type Option type values of IANA related to
      [RFC5213].
   o  Length: The length in bytes of Link Layer address
   o  The variable length link-layer address.  MAC address (if exists)
      is placed as value in this field.


5.  Security Considerations

   This document does not by itself introduce any security issues.



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6.  IANA Considerations

   IANA is requested to assign an option code to the following options
   from the option-code space defined in "DHCPv6 Options" section of the
   DHCPv6 specification [RFC3315].

           +---------------------------+-------+--------------+
           | Option Name               | Value | Described in |
           +---------------------------+-------+--------------+
           | OPTION_MHPTE              |  TBD  | Section 4.1  |
           | SUB_OPTION_FLOW_DESC      |  TBD  | Section 4.2  |
           | SUB_OPTION_QOS_INFO       |  TBD  | Section 4.3  |
           | SUB_OPTION_FR_PREFIX      |  TBD  | Section 4.4  |
           | SUB_OPTION_ROUTER_ADDRESS |  TBD  | Section 4.5  |
           | SUB_OPTION_INTERFACE_INFO |  TBD  | Section 4.6  |
           +---------------------------+-------+--------------+

                          Table 1: DHCPv6 Options


7.  Acknowledgements

   The authors acknowledge Mohamed Boucadair who provided useful
   comments for this document.


8.  References

8.1.  Normative References

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

   [RFC2629]  Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
              June 1999.

   [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.

   [I-D.ietf-mif-problem-statement]
              Blanchet, M. and P. Seite, "Multiple Interfaces Problem
              Statement", draft-ietf-mif-problem-statement-04 (work in
              progress), May 2010.

   [I-D.yang-mif-req]
              Yang, P., Seite, P., Williams, C., and J. Qin,
              "Requirements on multiple Interface (MIF) of simple IP",



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              draft-yang-mif-req-00 (work in progress), March 2009.

   [I-D.ietf-mext-flow-binding]
              Soliman, H., Tsirtsis, G., Montavont, N., Giaretta, G.,
              and K. Kuladinithi, "Flow Bindings in Mobile IPv6 and NEMO
              Basic Support", draft-ietf-mext-flow-binding-06 (work in
              progress), March 2010.

   [I-D.ietf-mext-binary-ts]
              Tsirtsis, G., Giaretta, G., Soliman, H., and N. Montavont,
              "Traffic Selectors for Flow Bindings",
              draft-ietf-mext-binary-ts-04 (work in progress),
              February 2010.

8.2.  Informative references

   [RFC3633]  Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
              Host Configuration Protocol (DHCP) version 6", RFC 3633,
              December 2003.

   [RFC4191]  Draves, R. and D. Thaler, "Default Router Preferences and
              More-Specific Routes", RFC 4191, November 2005.

   [RFC3484]  Draves, R., "Default Address Selection for Internet
              Protocol version 6 (IPv6)", RFC 3484, February 2003.

   [RFC2461]  Narten, T., Nordmark, E., and W. Simpson, "Neighbor
              Discovery for IP Version 6 (IPv6)", RFC 2461,
              December 1998.

   [RFC5213]  Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
              and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.

   [3GPP23402]
              "3GPP TS  23.402. Architecture enhancements for non-3GPP
              accesses.", June 2009.















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Authors' Addresses

   Behcet Sarikaya
   Huawei USA
   1700 Alma Dr. Suite 500
   Plano, TX  75075

   Phone: +1 972-509-5599
   Email: sarikaya@ieee.org


   Frank Xia
   Huawei USA
   1700 Alma Dr. Suite 500
   Plano, TX  75075

   Phone: +1 972-509-5599
   Email: xiayangsong@huawei.com


   Pierrick Seite
   France Telecom
   4, rue du Clos Courtel
   BP 91226
   Cesson-Sevigne,   35512
   France

   Email: pierrick.seite@orange-ftgroup.com























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