Internet DRAFT - draft-petrescu-netext-pmip-nemo

draft-petrescu-netext-pmip-nemo






NETEXT                                                       A. Petrescu
Internet-Draft                                                    M. Boc
Intended status: Informational                              C. Janneteau
Expires: January 12, 2013                                            CEA
                                                           July 11, 2012


                Network Mobility with Proxy Mobile IPv6
                 draft-petrescu-netext-pmip-nemo-01.txt

Abstract

   The Proxy Mobile IPv6 protocol supports Mobile Hosts moving
   independently, but not Mobile Routers in charge of moving networks.

   This draft addresses this problem.  The goal is to allow
   bidirectional communication between a Local Fixed Node (in the moving
   network) and a Correspondent Node (situated arbitrarily somewhere in
   the Internet).  First, a mechanism of "prefix division" is presented,
   whereby the Home Network Prefix typically assigned by PMIPv6 to a MH
   is used by MR to form Mobile Network sub-Prefix(es); they are used by
   LFNs within the moving network to form addresses; this avoids changes
   in the PMIPv6 protocol specification.  A second mechanism proposes
   enhancements to the use of the DHCPv6 Prefix Delegation protocol
   entities informing the PMIPv6 entities about the allocated MNP; this
   is achieved by equaling MNID and DUID.

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 12, 2013.

Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the
   document authors.  All rights reserved.



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   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
   to this document.


Table of Contents

   1.  Requirements notation  . . . . . . . . . . . . . . . . . . . .  3
   2.  Concentrated Description . . . . . . . . . . . . . . . . . . .  4
     2.1.  HNP Division . . . . . . . . . . . . . . . . . . . . . . .  4
     2.2.  DHCPv6-PD and PMIPv6 Enhancements  . . . . . . . . . . . .  7
   3.  Security Considerations  . . . . . . . . . . . . . . . . . . . 11
   4.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12
   5.  Normative References . . . . . . . . . . . . . . . . . . . . . 13
   Appendix A.  ChangeLog . . . . . . . . . . . . . . . . . . . . . . 14
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
































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1.  Requirements notation

   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].














































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2.  Concentrated Description

   The term Mobile Router has several meanings.  One of the agreed
   meanings at IETF, documented in terminology RFCs, is that of an
   entity implementing the Mobile IPv6 protocol with NEMOv6 extensions,
   and accomodating changes in its Care-of Address, maintaining a stable
   Home Address with the help of a Home Agent, and in charge of LFNs in
   a moving network whose addresses do not change.  Another meaning is
   that of a router which moves around and does not necessarily change
   its IP address.  In the context of this draft we consider this latter
   meaning.  We ignore whether or not the MR runs Mobile IPv6.

   The work presented in this draft is developped in the context of
   Proxy Mobile IPv6 [RFC5213].  With respect to prefix division,
   similar methods have been alluded to in the context of DHCPv6 Prefix
   Delegation by [I-D.krishnan-intarea-pd-epc] (with a slide
   presentation in the DHC WG at IETF77) and of OSPFv3 by
   draft-arkko-homenet-prefix-assignment-01.

   Mechanisms for supporting Mobile Routers with PMIPv6 and DHCPv6 are
   presented in [I-D.ietf-netext-pd-pmip] and preceding individual
   drafts.

   The methods presented in this draft are different from most if not
   all existing documented methods to accomodate moving networks with
   PMIPv6.  In particular, the HNP Division offers several MNPs for use
   by LFNs, does not modify PMIPv6, does not require the use of
   DHCPv6-PD but has an inconveninent in that it may not accommodate
   Ethernet LFNs with SLAAC.  The DHCPv6-PD and PMIPv6 enhancements
   offer MNPs potentially completely different than HNP, may use
   Ethernet LFNs with SLAAC, modify MAG, LMA, DHCP Relay and potentially
   DHCP Server.

   Moreover, the PMIPv6 and DHCPv6 enhancements presented in this draft
   rely on the use of MNID being equal to the DUID, a feature absent
   from existing proposals.  Also, with this mechanism the entity
   performing the allocation of an MNP is the DHCPv6 Server (and not the
   LMA).

2.1.  HNP Division

   The mechanism "HNP Division" divides the Home Network Prefix into two
   or more Mobile Network Prefixes (MNPs).

   It is assumed that in a domain running PMIPv6 the LMA assigns a Home
   Network Prefix (HNP) to the Mobile Host.  If we consider this Mobile
   Host to be a Mobile Router, in charge of a set of Local Fixed Nodes
   (LFNs) in a moving network, it is necessary to use a Mobile Network



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   Prefix (MNP) within the moving network.  Simply using HNP to form
   addresses for LFNs, without modifying MR behaviour with respect to
   its routing table, is not sufficient.

   The topology illustrated in the next figure depicts a domain where
   PMIPv6 is run, and a Mobile Router in charge of a set of LFNs forming
   a moving network.


                                 ----
                                | CN |
                                 ----
                                   |
                                Internet
                                   |
                                 ----
                                | LMA|
                                 ----
                                   |
                            Operator Network
                                /      \
                               /        \
                             ----      ----
                            |MAG1|    |MAG2|
                             ----      ----
                              | HNP
                             ----
                            | MR | ---> handover
                             ----
            ----   ----   ---- |
           |LFN2| |LFN3| |LFN5||
            ----   ----   ---- |MNP1 or MNP2
             |       |      |  |
            -------------------+


   For a HNP with prefix length 64, two or more MNPs are generated, each
   having a prefix length longer than 64.  For brevity and without
   losing generality, we present a detailed division example for a
   fictitious addressing system whose "IP" addresses are of a maximum
   length of 5 bits (instead of 128 bits of IPv6).










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                               A0 11000/5
                               A2 11010/5  To be used by LFN2
                               A3 11011/5  To be used by LFN3
                  +--------> MNP1 1101/4
                  |
                  |
      HNP 11000/2 +--------> A1 11001/5  To be used on egress of MR
                  |
                  |
                  +--------> MNP2 111/3
                               A4 11100/5
                               A5 11101/5  To be used by LFN5
                               A6 11110/5  To be used by LFN6
                               A7 11111/5


   In this example, the HNP/2 11000 is assigned by LMA to MR.  The MR
   divides this into MNP1 1101/4 and MNP2 111/3, and an address A1
   11001/5.  The MNP1 and MNP2 are used to help LFNs within the moving
   network to configure full /5 addresses.  This may be achieved either
   with DHCPv6 (MR or a DHCPv6 Server send these addresses) or with
   stateless address auto-configuration (MR or a Router send Router
   Advertisements containing MNP1 and/or MNP2).

   In most PMIPv6 implementations for MHs, the MAG contains a routing
   table entry with respect to the allocated HNP.  Depending on the
   nature of the link between MAG and MR, this entry has two different
   forms: [HNP, vif, *] in case of point-to-point links (typically used
   in cellular systems) and [HNP, eth, *] (typically used in WiFi
   hotspot shared links).  The vif is a virtual interface, e.g. "ppp0",
   whereas eth is a real interface, e.g. "eth0".

   In the case of point-to-point links, it is not necessary to add any
   additional behaviour for MR to work (LFN to be reachable from CN).
   It is sufficient for MR to perform HNP division as described above.

   On the contrary, in the case of shared links, it is necessary to
   perform an operation of Neighbor Discovery proxying on the Mobile
   Router.  When MAG receives a packet from CN addressed to LFN, it
   would solicit the MAC address of LFN on the MAG-MR link (even though
   LFN is not present on that link).  For this reason, the MR must
   pretend it owns the IP address of LFN and respond to that
   solicitation with its own MAC address.

   The HNP division mechanism requires that the MNP be part of the HNP
   (e.g.  MNP must have the leftmost n bits the same as the prefix
   length of HNP), and its length be longer.  In case of an HNP/64 and
   the use of Ethernet for LFNs, only the DHCPv6 protocol can be used by



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   LFNs, and not SLAAC, because stateless address auto-configuration is
   not possible for MNPs whose prefix length is longer than 64, the
   Interface ID being of length precisely 64 for Ethernet.

2.2.  DHCPv6-PD and PMIPv6 Enhancements

   A second mechanism considers the use of MNP completely different than
   HNP (may differ on the leftmost bit), hence the use of SLAAC with
   Ethernet LFNs and HNP/64 is possible, but whereby the PMIPv6 protocol
   implementation must be modified; this mechanism involves also the use
   of the DHCPv6 Prefix Delegation protocol.

   For this mechanism, we consider the following PMIP topology augmented
   with DHCP entities:


                                 ----
                                | CN |
                                 ----
                                   |
                                Internet
                                   |
                                 ----
                                | LMA|
                                 ----
               -----               |
              | DSe |------ Operator Network
               -----            /      \
                               /        \
                             ----      ----
                            |MAG1|    |MAG2|
                            |DRe1|    |DRe2|
                             ----      ----
                              | HNP
                             ----
                            | MR | ---> handover
                             ----
            ----   ----   ---- |
           |LFN2| |LFN3| |LFN5||
            ----   ----   ---- |MNP1 or MNP2
             |       |      |  |
            -------------------+


   The DSe entity is a DHCPv6 Server.  Each MAG also runs a DRe which is
   a DHCPv6 Relay.

   It is necessary to modify the DRe, LMA and MAG behaviour.  Depending



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   on deployment, it may be preferable to modify or to not modify the
   DHCPv6 Server as well.  In case it is not acceptable to modify the
   DSe the following protocol is proposed:


           LFN       MR        MAG      DSe     LMA      CN
            | RA defr |         |        |       |        |
            |<--------| DHCPReq |        |       |        |
            |         |-------->|        |       |        |
            |         |         | RelFwd |       |        |
            |         |         |------->|       |        |
            |         |         |DUID=MNID       |        |
            |         |         |        |       |        |
            |         |         | RelRep |       |        |
            |         |         |<-------|       |        |
            |         |         |  MNP   |       |        |
            |         |         |        |       |        |
            |         |         |  PBU MNID, MNP |        |
            |         |         |--------|------>|        |
            |         |         |  PBA MNID, MNP |        |
            |         |         |<-------|-------|        |
            |         | DHCPRep |        |       |        |
            | RA MNP  |<--------|        |       |        |
            |<--------|         |        |       |        |
            |         |         |        |       |        |
            |<--------|---------|========|=======|------->| app data
            |         |         |        |       |        |


   In case it is not acceptabe to modify the DSe the following protocol
   is proposed:




















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           LFN       MR        MAG      DSe     LMA      CN
            | RA defr |         |        |       |        |
            |<--------| DHCPReq |        |       |        |
            |         |-------->|        |       |        |
            |         |         | RelFwd |       |        |
            |         |         |------->|       |        |
            |         |         |DUID=MNID       |        |
            |         |         |        |       |        |
            |         |         |        | D2PU  |        |
            |         |         |        |------>|        |
            |         |         |        | MNID  |        |
            |         |         |        | MNP   |        |
            |         |         |        |       |        |
            |         |         |        | D2PA  |        |
            |         |         |        |<----- |        |
            |         |         |        | MNID  |        |
            |         |         | RelRep | MNP   |        |
            |         |         |<-------|       |        |
            |         |         |        |       |        |
            |         |         |  PBU MNID, MNP |        |
            |         |         |--------|------>|        |
            |         |         |        |       |        |
            |         |         |  PBA MNID, MNP |        |
            |         |         |<-------|-------|        |
            |         | DHCPRep |        |       |        |
            | RA MNP  |<--------|        |       |        |
            |<--------|         |        |       |        |
            |         |         |        |       |        |
            |<------------------=========|========------->| app data
            |         |         |        |       |        |


   D2PU and D2PA are new message formats, to be further defined.

   The structure of the PBU message is enhanced with respect to the
   original.  Its structure is presented in the following figure:















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     Proxy Binding Update Message (existing + Q)
                       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
                                       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                       |            Sequence #         |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |A|H|L|K|M|R|P|Q|  Reserved     |            Lifetime           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    Mobile Node Identifier Option (existing)
           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 Type  | Option Length |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |  Subtype      |          Identifier ...
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    Mobile Network Prefix (MNP) Option (NEW)
           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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |      Type     |   Length      |   Reserved    | Prefix Length |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
       +                                                               +
       |                                                               |
       +               Mobile Network Prefix (MNP)                     +
       |                                                               |
       +                                                               +
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   'R' flag in PBU: it must be reset.

   'Q' flag in PBU: it must be set.  It signifies this PBU is sent for
   an MNP (and not for an HNP).

   Type field in the MNP Option: a new type TBA.

   Length field in the MNP Option: the length of the MNP as was assigned
   by DHCP.








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3.  Security Considerations

   DHCPv6 and PMIPv6 have security options that should be used in this
   contect as well.

   Security risks exist in the process of MR performing proxy Neighbor
   Discovery on behalf of LFN, if done without explicit authorization
   provided by LFN.

   Security risks exist when performing D2PU and D2PA.









































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4.  Acknowledgements

   The mechanisms described in this draft were inspired by several
   discussions on the NETEXT and intarea email lists.  Contributors of
   these discussions are acknowledged here.

   In the process of filing for patent applications the lawyers provided
   comments which led to better descriptions.

   Administratively, this work has been performed in the framework of
   CELTIC project CP7-011 MEVICO.  The authors would like to acknowledge
   the contributions of their colleagues, although the views expressed
   are those of the authors and do not necessarily represent the
   project.





































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5.  Normative References

   [I-D.ietf-netext-pd-pmip]
              Zhou, X., Korhonen, J., Williams, C., and S. Gundavelli,
              "Prefix Delegation for Proxy Mobile IPv6",
              draft-ietf-netext-pd-pmip-01 (work in progress),
              October 2011.

   [I-D.krishnan-intarea-pd-epc]
              Krishnan, S., Garneij, F., Korhonen, J., and T.
              Savolainen, "Prefix Delegation in Evolved Packet Core
              networks", draft-krishnan-intarea-pd-epc-00 (work in
              progress), February 2010.

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

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
































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Appendix A.  ChangeLog

   The changes are listed in reverse chronological order, most recent
   changes appearing at the top of the list.

   From nil to draft-petrescu-nextex-pmip-nemo-00.txt:

   o  The -00 version is mostly a placeholder containing the essence of
      the mechanisms.

   From draft-petrescu-netext-pmip-nemo-00 to -01:

   o  Updated the address of authors.

   o  Aspects described in the draft are now implemented.




































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Authors' Addresses

   Alexandru Petrescu
   CEA, LIST
   Communicating Systems Laboratory, Point Courrier 173
   Palaiseau,   F-91120
   France

   Phone: +33 169089223
   Email: alexandru.petrescu@cea.fr


   Michael Mathias Boc
   CEA, LIST
   Communicating Systems Laboratory, Point Courrier 173
   Palaiseau,   F-91120
   France

   Phone: +33 (0) 169083976
   Email: michael.boc@cea.fr


   Christophe Janneteau
   CEA, LIST
   Communicating Systems Laboratory, Point Courrier 173
   Palaiseau,   F-91120
   France

   Phone: +33 (0) 169089182
   Email: christophe.janneteau@cea.fr





















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