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Versions: (draft-zhou-netext-pd-pmip) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 RFC 7148

Netext WG                                                        X. Zhou
Internet-Draft                                           ZTE Corporation
Intended status: Standards Track                             J. Korhonen
Expires: May 3, 2012                              Nokia Siemens Networks
                                                             C. Williams
                                                              Consultant
                                                           S. Gundavelli
                                                                   Cisco
                                                        October 31, 2011


                Prefix Delegation for Proxy Mobile IPv6
                    draft-ietf-netext-pd-pmip-01.txt

Abstract

   DHCPv6 Prefix Delegation can be used to assign a prefix or prefixes
   to a mobile router for use on the links in the mobile network as
   specified in [RFC6276] but not supported in Proxy Mobile IPv6.  This
   document specifies an extension to Proxy Mobile IPv6 protocol for
   supporting network mobility using DHCPv6-based Prefix Delegation.

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 May 3, 2012.

Copyright Notice

   Copyright (c) 2011 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.  Convention and Terminology . . . . . . . . . . . . . . . . . .  4
   3.  DHCPv6 Prefix Delegation for Proxy Mobile IPv6 . . . . . . . .  5
     3.1.  Assumptions  . . . . . . . . . . . . . . . . . . . . . . .  5
     3.2.  Network Mobility Service . . . . . . . . . . . . . . . . .  5
     3.3.  Binding association with the delegated prefix  . . . . . .  6
       3.3.1.  Mobile Router initiated prefix delegation in PMIPv6  .  6
       3.3.2.  Refreshing the Delegated Prefix in Proxy Mobile
               IPv6 . . . . . . . . . . . . . . . . . . . . . . . . .  7
     3.4.  Mobile Access Gateway Operation  . . . . . . . . . . . . .  8
       3.4.1.  Extension to Binding Update List Entry Data
               Structure  . . . . . . . . . . . . . . . . . . . . . .  8
       3.4.2.  Forwarding . . . . . . . . . . . . . . . . . . . . . .  8
       3.4.3.  Handover . . . . . . . . . . . . . . . . . . . . . . .  8
     3.5.  Local Mobility Anchor Operation  . . . . . . . . . . . . .  9
       3.5.1.  Extension to Binding Cache Entry Data Structure  . . .  9
       3.5.2.  Forwarding . . . . . . . . . . . . . . . . . . . . . .  9
   4.  Security Considerations  . . . . . . . . . . . . . . . . . . . 10
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 11
   6.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
     6.1.  Normative References . . . . . . . . . . . . . . . . . . . 12
     6.2.  Informative References . . . . . . . . . . . . . . . . . . 12
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13



















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1.  Introduction

   DHCPv6 Prefix Delegation [RFC3633] (DHCPv6-PD) can be used to assign
   mobile network prefix(es) to a mobile router (MR) as specified in
   DHCPv6 Prefix Delegation for Network Mobility (NEMO) [RFC6276].
   However, there is a gap currently for this NEMO support in Proxy
   Mobile IPv6 (PMIPv6) architecture.  If a mobile router (MR) is
   provided PMIPv6 Protocol as its mobility management when connecting
   the network and use DHCPv6-PD to obtain prefix(es) for the nodes in
   the mobile network behind the MR, currently neither the Mobile Access
   Gateway (MAG) nor the Local Mobility Anchor (LMA) can be able to
   identify the packet including delegated prefix(es).  When the MR as a
   requesting router (RR) uses DHCPv6-PD to obtain the delegated
   prefix(es), these prefix(es) MUST be associated with the PMIPv6
   binding.  Otherwise the packets sourced from or destined to the
   delegated prefix will be discarded by the MAG or the LMA.  This
   document describes extension to PMIPv6 for supporting prefix
   delegation.

































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2.  Convention and Terminology

   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].

   All the mobility related terms used in this document are to be
   interpreted as defined in Mobile IPv6 (MIPv6) [RFC6275], Network
   Mobility Basic Support protocol [RFC3963], Proxy Mobile IPv6
   specification [RFC5213], DHCPv6-PD for NEMO [RFC6276], DHCPv6-PD
   [RFC3633] and Mobility Related Terminology [RFC3753].  This document
   does not define any new terms.







































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3.  DHCPv6 Prefix Delegation for Proxy Mobile IPv6

3.1.  Assumptions

   This specification extends PMIPv6 to assign a mobile network prefix
   for supporting network mobility.  The specification assumes that a MR
   is a regular IPv6 router without extension for mobility managements.
   The MR sends the packets from its mobile network to the MAG and the
   MAG delivers the packets to the mobile network via the MR.

   In order to use DHCPv6-PD as mobile network prefix assignment
   mechanism in mobile networks, this specification has following
   assumptions.

   o  The mobile router (MR) MUST be able to function as a requesting
      router (RR).

   o  The delegating router (DR) can be located either at LMA or some
      other device in the PMIPv6 domain.

   o  The MAG MUST have a DHCPv6 Relay Agent functionality (as described
      in [RFC5213] to be able to intercept the related DHCPv6 message
      sourced from the MR.

   o  The MR (as a RR) MUST either obtain the Home Network Prefix (HNP)
      before initiating the DHCPv6-PD procedure or in case of stateful
      address configuration simultaneously while configuring the Mobile
      Node Home Address (MN-HoA).

   o  All the mobile network prefixes managed in the DR MUST be
      reachable via local mobility anchor (LMA).

   o  The MR (as a RR) SHOULD support Prefix Exclude Option for
      DHCPv6-PD as described in [I-D.ietf-dhc-pd-exclude].

3.2.  Network Mobility Service

   The network mobility service of a MR is managed by the Mobile Node's
   (MN) policy profile defined in [RFC5213].  During mobile router
   initial attach procedure, the mobile access gateway (MAG) MUST
   identify the MR and acquire the MR's policy profile to determine
   whether the network mobility service is offered to the MR.  If the
   network mobility service needs to be offered to the mobile node, the
   mobile access gateway MUST set the Mobile Router Flag (R) when
   sending the Proxy Binding Update (PBU) message to the LMA.






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3.3.  Binding association with the delegated prefix

3.3.1.  Mobile Router initiated prefix delegation in PMIPv6

   +-------------+    +--------------+   +--------+    +----------+
   |Mobile Router|    |      MAG     |   |  LMA   |    |Delegating|
   |(Req. Router)|    |(DHCPv6 Relay)|   +--------+    |  Router  |
   +-------------+    +--------------+        |        +----------+
          |                  |                |             |
          |                  |o==============o|             |
   1)     |                  | PMIPv6 tunnel  |             |
          |                  |o==============o|             |
   2)     |-- Solicit ------>|                |             |
          |                  |                |             |
   3)     |                  |--- PBU ------->|             |
          |                  |                |             |
   4)     |                  |<-- PBA --------|             |
          |                  |                |             |
   5)     |                  |--- Solicit ----------------->|
          -                  -                -             - <-+
   6)     |                  |<-- Advertise ----------------|   |
          |                  |                |             |
   7)     |<- Advertise -----|                |             |  Opt
          |                  |                |             |  ion
   8)     |-- Request ------>|                |             |  al.
          |                  |                |             |
   9)     |                  |--- Request ----------------->|   |
          -                  -                -             - <-+
   10)    |                  |<-- Reply---------------------|
          |                  |                |             |
   11)    |<-- Reply --------|                |             |
          |                  |                |             |

    Figure 1: Prefix Delegation in PMIPv6 during the initial attachment
                           to the PMIPv6 Domain

   The steps of the procedures in Figure 1 are as following:

   1.   The PMIPv6 tunnel is set up between the MAG and LMA as described
        in [RFC5213].  The MAG has the function of DHCPv6 Relay Agent
        between the MN and the DHCPv6 server and intercept all the
        DHCPv6 related messages.

   2.   The MR which acts as a "Requesting Router" as described in
        [RFC3633] sends DHCPv6 SOLICIT message including one or more
        IA_PD option(s) to the MAG to acquire the delegated prefix(es).





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   3.   Upon receiving DHCPv6 SOLICIT the MAG sends a PBU message
        including a Mobile Network Prefix (MNP) mobility option as
        defined in Section 4.3 of [RFC3963] to the LMA.  All the
        considerations from Section 5.3.1 of [RFC5213] MUST be applied
        on the encapsulated Proxy Binding Update message.  If the MAG
        does not know the delegated prefix, then mobile network prefix
        in the MNP option MUST be set to unspecified address "::" and
        prefix length to 0.  The LMA either assigns the MR a new
        delegated prefix or returns an existing one.

   4.   On reception of the PBU the LMA returns the assigned prefix in
        the MNP option carried by a Proxy Binding Acknowledgment (PBA)
        to the MAG, unless the prefix was an unspecified address "::".
        The assigned prefix is the same one which will be assigned via
        DHCPv6PD in step 6 which MUST be added the delegated prefix(es)
        in its binding cache which is extended as in Section 3.5.1.

   5.   The DHCPv6 Relay Agent on the MAG as described in [RFC3315]
        relays the DHCPv6 SOLICIT message to the delegation router.  The
        DR inserts one or more IA_PD option(s) including the delegated
        prefix(es) to the reply message.

        Note: steps 6 to 9 are not present if DHCPv6 Rapid Commit is
        used.

   6.   The DR sends delegated prefix(es) in one or more IA_PD(s) to the
        MAG (DHCPv6 Relay Agent) inside the DHCPv6 ADVERTISE message.

   7.   The MAG relays the DHCPv6 ADVERTISE message to the MN.

   8.   The MN sends DHCPv6 REQUEST message with the IA_PD option(s)
        received from previous message to the MAG (DHCPv6 Relay Agent).

   9.   The MAG relays the DHCPv6 REQUEST message to the DR.

   10.  The DR responses to the REQUEST from the MAG using DHCPv6 REPLY
        message.

   11.  The MN receives one or more IA_PD prefix(es) in the DHCPv6 REPLY
        message from the MAG.

3.3.2.  Refreshing the Delegated Prefix in Proxy Mobile IPv6

   When the MR sends DHCPv6 Renew messages to extend the lifetime of the
   delegated prefix, the messages are also intercepted by the MAG and
   relayed to the DR.  If the MAG finds that the lifetime of the
   delegated prefix which is stored in the IA_PD Prefix Option carried
   by the DHCPv6 Reply message set to zero, the MAG MUST trigger a PBU



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   to remove the binding for that mobile network prefix.

3.4.  Mobile Access Gateway Operation

3.4.1.  Extension to Binding Update List Entry Data Structure

   In order to support this specification, the conceptual Binding Update
   List Entry (BULE) data structure needs to be extended with a new
   prefix information field as [RFC3963] does.  This prefix information
   field is used to store the MNP information which is assigned to the
   MR in the PBA.

3.4.2.  Forwarding

   Forwarding packets sent to the MR's MNP:

   o  On receiving a packet from the bi-directional tunnel established
      with the MR's LMA, the MAG MUST use the destination address of the
      inner packet to forward it on the interface where the destination
      MNP is hosted.

   Forwarding packets sent by the MR:

   o  On receiving packets from a MR connected to its access link, the
      MAG MUST ensure that there is an established binding for the MR
      and its LMA before tunneling the packet to the MR's LMA.

   Other considerations from Section 6.10.5 or [RFC5213] also apply
   here.

3.4.3.  Handover

   When the MR moves from the previously attached MAG to the newly
   attached target MAG, the newly attached target MAG MAY know the
   mobile network prefix which is assigned during the previous
   attachment from some network element, e.g. from the previous MAG.  It
   is out of scope of this specification that how the newly attached MAG
   could obtain the previously assigned mobile network prefix.  After
   handover to the new target MAG, a PBU message including the assigned
   mobile network prefix (if available) MUST be sent from the new target
   MAG to the LMA.  The LMA MUST check the mobile network prefix in the
   PBU message and return the same assigned mobile network prefix in the
   PBA message.  If the previously assigned mobile network prefix is not
   available in the new target MAG, the new target MAG MUST contain the
   mobile network prefix set to unspecified address "::" and the prefix
   length to 0 in the PBU message.  In this case, the LMA MUST return
   the same previously assigned mobile network prefix in PBA.




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3.5.  Local Mobility Anchor Operation

3.5.1.  Extension to Binding Cache Entry Data Structure

   In order to support this specification, the conceptual Binding Cache
   Entry (BCE) data structure needs to be extended with a new prefix
   information field as [RFC3963] does.  This prefix information field
   is used to store the mobile network prefix information which is
   assigned to the BCE in the PBA during the procedure of binding
   association with the delegated prefix in Section 3.2

3.5.2.  Forwarding

   Intercepting packets sent to the MR's mobile network prefix:

   o  When the LMA is serving to the MR, it MUST be able to receive
      packets destined to the MR's mobile network.  In order to receive
      those packets, the LMA MUST advertise a connected route into the
      routing infrastructure for the MR's MNP(s).

   Forwarding packets to the MR:

   o  On receiving a packet from a correspondent node with the
      destination address matching the MR's MNP(s) the LMA MUST forward
      the packet through the bi-directional tunnel set up for the MR.

   Other considerations from Section 5.6.2 of [RFC5213] also apply here.
























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4.  Security Considerations

   All security considerations from the base Proxy Mobile IPv6
   [RFC5213], DHCPv6 Prefix Delegation specification [RFC3633] apply
   when using the extensions defined in this document.














































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5.  IANA Considerations

   This document reuses the mobile network prefix option defined in
   [RFC3963] in Proxy Mobile IPv6 to assign the mobile network prefix
   via DHCPv6 Prefix Delegation.  It does not introduce any additional
   IANA considerations.













































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6.  References

6.1.  Normative References

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

   [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.

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

   [RFC3963]  Devarapalli, V., Wakikawa, R., Petrescu, A., and P.
              Thubert, "Network Mobility (NEMO) Basic Support Protocol",
              RFC 3963, January 2005.

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

   [RFC6275]  Perkins, C., Johnson, D., and J. Arkko, "Mobility Support
              in IPv6", RFC 6275, July 2011.

   [RFC6276]  Droms, R., Thubert, P., Dupont, F., Haddad, W., and C.
              Bernardos, "DHCPv6 Prefix Delegation for Network Mobility
              (NEMO)", RFC 6276, July 2011.

6.2.  Informative References

   [I-D.ietf-dhc-pd-exclude]
              Korhonen, J., Savolainen, T., Krishnan, S., and O. Troan,
              "Prefix Exclude Option for DHCPv6-based Prefix
              Delegation", draft-ietf-dhc-pd-exclude-03 (work in
              progress), August 2011.

   [RFC3753]  Manner, J. and M. Kojo, "Mobility Related Terminology",
              RFC 3753, June 2004.












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Authors' Addresses

   Xingyue Zhou
   ZTE Corporation
   No.50 Software Avenue, Yuhuatai District
   Nanjing
   China

   Phone: +86-25-8801-4634
   Email: zhou.xingyue@zte.com.cn


   Jouni Korhonen
   Nokia Siemens Networks
   Linnoitustie 6
   Espoo  FIN-02600
   Finland

   Email: jouni.nospam@gmail.com


   Carl Williams
   Consultant
   San Jose, CA
   USA

   Email: carlw@mcsr-labs.org


   Sri Gundavelli
   Cisco
   170 West Tasman Drive
   San Jose, CA  95134
   USA

   Email: sgundave@cisco.com















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