One document matched: draft-perkins-autoconf-leghost-00.txt

MANET Autoconfiguration (Autoconf)                            C. Perkins
Internet-Draft                                                   Tellabs
Intended status: Informational                                T. Clausen
Expires: April 21, 2011                              Ecole Polytechnique
                                                        October 18, 2010


            MANET address autoconfiguration for legacy hosts
                   draft-perkins-autoconf-leghost-00







Abstract

   This document describes methods by which a host running only DHCPv6
   or Neighbor Discovery can obtain an address suitable for use in an ad
   hoc network.

Status of This Memo

   This Internet-Draft is submitted to IETF 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
   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 April 21, 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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   carefully, as they describe your rights and restrictions with respect
   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
   2.  Details about DHCPv6 operation  . . . . . . . . . . . . . . . . 4
   3.  Details about operation using Router Advertisement  . . . . . . 4
   4.  Pictorial representation of address assignment  . . . . . . . . 4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
     7.1.  Normative References  . . . . . . . . . . . . . . . . . . . 5
     7.2.  Informative References  . . . . . . . . . . . . . . . . . . 5
   Appendix A.  Acknowledgements . . . . . . . . . . . . . . . . . . . 5

































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1.  Introduction

   This document describes methods by which a host running only DHCPv6
   [RFC3315] or Neighbor Discovery [RFC4862] can obtain an address
   suitable for use in an ad hoc network.  Let us call such a host to be
   a "legacy host".  It is agreed that legacy hosts are not routers and
   do not forward packets.

   The basic mechanism in our proposal is very simple.  DHCP Request
   packets and certain Router Solicitations are treated as requests to
   obtain an address.  Any router receiving such an address allocation
   request initiates an Address Allocation protocol procedure
   appropriate for the MANET (Mobile Ad Hoc Network) in which the router
   resides.  There are numerous examples of such address allocation
   protocols [bernardos-survey].  In the case of routers running
   proactive MANET protocols, simple inspection of the routing table may
   suffice for the router to determine a unique address for the
   requesting host.  In the case of routers running only reactive
   protocols, additional steps may be necessary.

   Once the router has determined a unique address appropriate for the
   requesting host, the router returns either DHCP Request or Router
   Advertisement to the requesting host.  In the case of the Router
   Advertisement, the router presumes that the host will follow standard
   practice.  Namely, the host is presumed to make use of the prefix
   provided by the router along with the host ID of the requesting host.
   In many cases, the prefix supplied by the router will be such that no
   link-local addresses are supported within the range of addresses
   defined by the prefix, because the prefix will be /128.  Such
   allocations do not require additional steps by the host, and the /128
   prefix supplied by the router will typically already contain the host
   ID of the requesting host.

   The cases of interest may be classified into two general categories,
   depending upon whether or not the ad hoc network (i.e., the MANET) is
   attached to the Internet.  If the MANET is attached to the Internet,
   then the MANET as a whole is addressable from the Internet according
   to a routing prefix appropriate for the point of attachment of the
   MANET.  In this case, addresses assigned to the requesting host by
   the allocating router will be selected from the routing prefix for
   the MANET.

   Otherwise, the address will be selected from a generalized MANET
   prefix (MANET_LOCAL_PREFIX) which is not reachable from the Internet.
   Any address assignments from the MANET_LOCAL_PREFIX are only valid
   within the connected domain defined by the routers in the MANET
   containing the legacy host and its neighboring router(s).  The
   operation of legacy hosts using such addresses allocated form the



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   MANET_LOCAL_PREFIX may be viewed as analogous to the operation of
   hosts making use of IPv6 Unique Local Addresses (ULAs) [RFC4193].  In
   particular, any such host MUST NOT accept MANET_LOCAL an address
   allocation from two different neighboring routers; only one
   allocation can be accepted, and additional allocations SHOULD be
   refused.

2.  Details about DHCPv6 operation

   In the absence of any additional information, the router returning
   the DHCP Reply MUST indicate a prefix length of /128 for the address
   given in the DHCP Reply.

3.  Details about operation using Router Advertisement

   After a legacy host has configured a link-local address, it may (if
   so configured) issue a Router Solicitation in order to obtain routing
   information from a local router.  Any router receiving this
   Solicitation MAY reply with an appropriate Router Advertisement,
   unicast to the soliciting host.  In the absence of any additional
   information, the router transmitting the Router Advertisement MUST
   indicate a prefix length of /128 for the address given in the
   Advertisement.

4.  Pictorial representation of address assignment

                      A router and a legacy host

                   <~~~~~~~~~~~~~+~~~~~~~~~~~~~>
                                 |      <~~~~~~+~~~~~~>
                              +--|--+       +--|--+
                              | RtrA|<=====>|Host |
                              +-----+       +-----+

      Figure 1: RtrA can send and receive packets from Host.


   In the situation depicted in Figure 1, RtrA may receive a DHCP
   Request, or a Router Solicitation, from the Host.  In either case, if
   RtrA is able to obtain an appropriate address for use by the Host, it
   may provide that address to the Host by either of DHCP Reply or a
   Router Advertisement.

5.  Security Considerations

   This document does not have any security considerations.





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6.  IANA Considerations

   This document does not have any IANA actions.

7.  References

7.1.  Normative References

   [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.

   [RFC4193]           Hinden, R. and B. Haberman, "Unique Local IPv6
                       Unicast Addresses", RFC 4193, October 2005.

   [RFC4862]           Thomson, S., Narten, T., and T. Jinmei, "IPv6
                       Stateless Address Autoconfiguration", RFC 4862,
                       September 2007.

7.2.  Informative References

   [bernardos-survey]  Bernardos, CJ., Calderon, M., and H. Moustafa,
                       "Survey of IP address autoconfiguration
                       mechanisms for MANETs",
                       draft-bernardos-manet-autoconf-survey-05.txt
                       (work in progress), 2010.

Appendix A.  Acknowledgements

   This document has benefitted from discussions with the following
   people, in no particular order: Buu-Minh Ta.

Authors' Addresses

   Charles E. Perkins
   Tellabs

   Phone: +1-408-435-0777 x337
   EMail: charliep@wichorus.com


   Thomas Clausen
   Ecole Polytechnique

   Phone: +33-671-116-128
   EMail: thomas@thomasclausen.org




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