DMM Working Group                                                 Z. Yan
Internet-Draft                                                     CNNIC
Intended status: Standards Track                                  J. Lee
Expires: October 14, 2015                           Sangmyung University
                                                                  X. Lee
                                                          April 12, 2015

               Home Network Prefix Renumbering in PMIPv6


   In the basic Proxy Mobile IPv6 (PMIPv6) specification, a Mobile Node
   (MN) is assigned with a 64-bit Home Network Prefix (HNP) during its
   initial attachment for the Home Address (HoA) configuration.  During
   the movement of the MN, this prefix remains unchanged and in this way
   it is unnecessary for the MN to reconfigure its HoA and reconnect the
   ongoing communications.  However, the current protocol (RFC5213)
   does not specify related operations to support the MN to timely
   receive and use a new HNP when the allocated HNP changes.  In this
   draft, a possible solution to support the HNP renumbering is
   proposed, as an update of RFC5213.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in RFC 2119.

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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   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on October 14, 2015.

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Copyright Notice

   Copyright (c) 2015 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
   carefully, as they describe your rights and restrictions with respect
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Usage scenarios . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Protocol  . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Message format  . . . . . . . . . . . . . . . . . . . . . . .   5
   5.  Other issues  . . . . . . . . . . . . . . . . . . . . . . . .   5
   6.  Security considerations . . . . . . . . . . . . . . . . . . .   5
   7.  Normative References  . . . . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   Network managers currently prefer to Provider Independent (PI)
   addressing for IPv6 to attempt to minimize the need for future
   possible renumbering.  However, widespread use of PI addresses may
   create very serious Border Gateway Protocol (BGP) scaling problems.
   It is thus desirable to develop tools and practices that may make
   IPv6 renumbering a simpler process to reduce demand for IPv6 PI space
   [RFC6879].  In this draft, we aims to solve the HNP renumbering
   problem when the HNP in PMIPv6 [RFC5213] is not a PI type.

2.  Usage scenarios

   There are a number of reasons why the HNP renumbering support is a
   useful.  A few are identified below:

   o  Scenario 1: the PMIPv6 service provider is assigned with the HNP
      set from the (uplink) Internet Service Provider (ISP), and then
      the HNP renumbering may happen if the PMIPv6 service provider
      switches to a different ISP.

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   o  Scenario 2: multiple Local Mobility Anchors (LMAs) may be deployed
      by the same PMIPv6 service provider, and then each LMA may serve
      for a specific HNP set.  In this case, the HNP of an MN may change
      if the current serving LMA switches to another LMA but without
      inheriting the assigned HNP set [RFC6463].

   o  Scenario 3: the PMIPv6 HNP renumbering may be caused by the re-
      building of the network architecture as the companies split,
      merge, grow, relocate or reorganize.  For example, the PMIPv6
      service provider may reorganize its network topology.

   In the scenario 1, we assume that only the HNP is renumbered while
   the serving LMA remains unchanged and this is the basic scenario of
   this document.  In the scenario 2 and 3, more complex results may be
   caused, for example, the HNP renumbering may happen due to the
   switchover of serving LMA.

   In the Mobile IPv6 (MIPv6), when the home network prefix changes
   (maybe due to the above reasons), the Home Agent (HA) will actively
   notify the new prefix to the MN and then the renumbering of the HoA
   can be well supported [RFC6275].  While in the basic PMIPv6, the
   PMIPv6 binding is triggered by the Mobile Access Gateway (MAG), which
   detects the attachment of the MN.  When the HNP renumbering happens,
   a scheme is also needed for the LMA to immediately initiate the
   PMIPv6 binding state refreshment.  Although this issue is also
   discussed in the [RFC5213] (Section 6.12), the related solution has
   not been specified.

3.  Protocol

   When the HNP renumbering happens in PMIPv6, the LMA has to notify the
   new HNP to the MAG that has to announce the new HNP to the MN
   accordingly.  Also, the LMA and the MAG must delete the created
   routing states for the renumbered prefix.  To support this procedure,
   [RFC7077]can be adopted which specifies asynchronously update from
   the LMA to the MAG about the updated session parameters.  This
   document considers the following two cases:

   (1)HNP is renumbered in the same LMA

   In this case, the LMA remains unchanged as in the scenario 1 and
   scenario 3.  The operation steps are shown in Figure 1.

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   +-----+                +-----+                +-----+
   | MN  |                | MAG |                | LMA |
   +-----+                +-----+                +-----+
     |                      |                      |
     |                      |           Allocate new HNP
     |                      |                      |
     |                      |<------------- UPN ---|
     |                      |                      |
     |               Update routing status         |
     |                      |                      |
     |<-----RA/DHCP --------|                      |
     |                      |                      |
   HoA Configuration        |                      |
     |                      |                      |
     |                      |--- UNA ------------->|
     |                      |                      |
     |                      |      Update routing status
     |                      |                      |

             Figure 1: Signaling call flow of HNP renumbering

   o  When the PMIPv6 service provider renumbers the HNP set in the same
      LMA, the serving LMA will initiate the HNP renumbering operation.
      The LMA allocates a new HNP for the related MN.

   o  The LMA sends the Update Notification (UPN) message to the MAG to
      update the HNP information.  If the DHCP is used in PMIPv6 to
      allocate the HoA, the new HNP should be also notified to the DHCP

   o  After the MAG receives this UPN message, it recognizes that the
      related MN has a new HNP.  Then the MAG should notify the MN about
      the new HNP with an RA message or allocate a new address within
      the new HNP with a DHCP message.

   o  When the MN obtains the new HNP information, it deletes the old
      HoA and configures a new HoA (with the newly allocated HNP).

   o  The MAG sends back the Update Notification Acknowledgement (UNA)
      to the LMA for the notification of successful update of the HNP,
      related binding state, and routing state.  Then the LMA updates
      the routing information corresponding to the MN to replace the old
      HNP with the new one.

   (2) HNP renumbering caused by LMA switchover

   Because the HNP is assigned by the LMA, the HNP renumbering may be
   caused by the LMA switchover, as in the scenario 2 and scenario 3.

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   The information of LMA is the basic configuration information of MAG.
   When the LMA changes, the related profile should be updated by the
   operator.  In this way, the MAG will initiate the re-registration to
   the new LMA as specified in RFC5213.  When the HNP renumbering is
   caused in this case, the new HNP information will be sent by the LMA.
   Accordingly, the MAG will withdraw the old HNP information of the MN
   and advise the new HNP to the MN as related steps in Section 3.1.

4.  Message format

   (1)UPN message

   In the UPN message sent from the LMA to the MAG, the notification
   reason is set to 2 (UPDATE-SESSION-PARAMETERS).  Besides, the HNP
   Option containing the new HNP and the Mobile Node Identifier Option
   carrying Identifier of MN are contained as Mobility Options of UPN.

   (2)RA Message

   When the RA message is used by the MAG to advise the new HNP, two
   Prefix Information options are contained in the RA message [RFC2461].
   In the first Prefix Information Option, the old HNP is carried but
   both the related Valid Lifetime and Preferred Lifetime are set to 0.
   In the second Prefix Information Option, the new HNP is carried with
   the Valid Lifetime and Preferred Lifetime set to larger than 0.

   (3)DHCP Message

   When the DHCP is used in PMIPv6 to configure the address for the MN,
   a new IPv6 HoA is generated based on the new HNP.  Trigged by the UPN
   message, the MAG will request the new HoA from the DHCP server first
   and then the MAG updates the allocated HoA to the MN through the DHCP
   server-initiated configuration exchange [RFC3315].

5.  Other issues

   In order to maintain the reachability of the MN, the DNS resource
   record corresponding to this MN may need to be updated when the HNP
   of MN changes [RFC3007].  However, this is out the scope of this

6.  Security considerations

   This extension causes no further security problem.  The security
   considerations in [RFC5213] and [RFC7077] are enough for the basic
   operation of this draft.

   Other security issues will be analyzed further.

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7.  Normative References

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

   [RFC3007]  Wellington, B., "Secure Domain Name System (DNS) Dynamic
              Update", RFC 3007, November 2000.

   [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.

   [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.

   [RFC6463]  Korhonen, J., Gundavelli, S., Yokota, H., and X. Cui,
              "Runtime Local Mobility Anchor (LMA) Assignment Support
              for Proxy Mobile IPv6", RFC 6463, February 2012.

   [RFC6879]  Jiang, S., Liu, B., and B. Carpenter, "IPv6 Enterprise
              Network Renumbering Scenarios, Considerations, and
              Methods", RFC 6879, February 2013.

   [RFC7077]  Krishnan, S., Gundavelli, S., Liebsch, M., Yokota, H., and
              J. Korhonen, "Update Notifications for Proxy Mobile IPv6",
              RFC 7077, November 2013.

Authors' Addresses

   Zhiwei Yan
   No.4 South 4th Street, Zhongguancun
   Beijing  100190

   EMail: yan@cnnic.cn

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   Jong-Hyouk Lee
   Sangmyung University
   31, Sangmyeongdae-gil, Dongnam-gu
   Republic of Korea

   EMail: jonghyouk@smu.ac.kr

   Xiaodong Lee
   No.4 South 4th Street, Zhongguancun
   Beijing  100190

   EMail: xl@cnnic.cn

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