DMM Working Group                                                 Z. Yan
Internet-Draft                                                     CNNIC
Intended status: Standards Track                                  J. Lee
Expires: July 9, 29, 2017                              Sangmyung University
                                                                  X. Lee
                                                                   CNNIC
                                                        January 5, 25, 2017

               Home Network Prefix Renumbering in PMIPv6
                       draft-ietf-dmm-hnprenum-04
                       draft-ietf-dmm-hnprenum-05

Abstract

   In the basic Proxy Mobile IPv6 (PMIPv6) specification, a Mobile Node
   (MN) is assigned with a Home Network Prefix (HNP) during its initial
   attachment and the MN configures its Home Address (HoA) with the HNP.
   During the movement of the MN, the HNP remains unchanged to keep
   ongoing communications associated with the HoA.  However, the current
   PMIPv6 specification does not specify related operations when an HNP
   renumbering is happened.  In this document, a solution to support the
   HNP renumbering is proposed, as an update of the PMIPv6
   specification.

Requirements Language

   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]

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
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   This Internet-Draft will expire on July 9, 29, 2017.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Usage Scenarios . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  PMIPv6 Extensions . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Session Connectivity  . . . . . . . . . . . . . . . . . . . .   5
   5.  Message Format  . . . . . . . . . . . . . . . . . . . . . . .   6
   6.  Other Issues  . . . . . . . . . . . . . . . . . . . . . . . .   6
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   7   6
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   Network managers currently prefer Provider Independent (PI)
   addressing for IPv6 to attempt to minimize the need for future
   possible renumbering.  However, a widespread use of PI addresses may
   cause Border Gateway Protocol (BGP) scaling problems [RFC7010].  It
   is thus desirable to develop tools and practices that make IPv6
   renumbering a simpler process to reduce demand for IPv6 PI space
   [RFC6879].  In this document, we aim to solve the HNP renumbering
   problem when the HNP in PMIPv6 [RFC5213] is not the type of PI.

2.  Usage Scenarios

   There are a number of reasons why the HNP renumbering support in
   PMIPv6 is useful and some scenarios are identified below:

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

   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
   considered in this document.  In the scenario 2 and scenario 3, more
   complex results may be caused, for example, the HNP renumbering may
   happen due to the switchover of a serving LMA.

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

3.  PMIPv6 Extensions

   When the HNP renumbering happens in PMIPv6, the LMA has to notify a
   new HNP to an MAG and then the MAG has to announce the new HNP to the
   attached MN accordingly.  Also, the LMA and the MAG must update the
   routing states for the HNP and the related addresses.  To support
   this procedure, [RFC7077] can be adopted which specifies an
   asynchronous update from the LMA to the MAG about specific session
   parameters.  This document considers the following two cases:

   (1) HNP is renumbered under 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.

   +-----+                +-----+                +-----+
   | MN  |                | MAG |                | LMA |
   +-----+                +-----+                +-----+
     |                      |                      |
     |                      |           Allocate new HNP
     |                      |                      |
     |                      |<------------- UPN ---|
     |                      |                      |
     |                      |                      |
     |                      |                      |
     |<-----RA/DHCP --------|                      |
     |                      |                      |
   Address configuration    |                      |
     |                      |                      |
     |              Update binding&routing states  |
     |                      |                      |
     |                      |--- UPA ------------->|
     |                      |                      |
     |                      |     Update binding&routing states
     |                      |                      |

           Figure 1: Signaling call flow of the HNP renumbering

   o  When a PMIPv6 service provider renumbers the HNP set under 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 Dynamic Host Configuration
      Protocol (DHCP) is used to allocate the address, the new HNP
      should be also notified to the DHCP infrastructure.

   o  Once the MAG receives this UPN message, it recognizes that the
      related MN has the new HNP.  Then the MAG should notify the MN
      about the new HNP with a Router Advertisement (RA) message or
      allocate a new address within the new HNP through a DHCP
      procedure.

   o  After the MN obtains the HNP information through the RA message,
      it deletes the old HoA and configures a new HoA with the newly
      allocated HNP.

   o  When the new HNP is announced or the new address is configured to
      the MN successfully, the MAG updates the related binding and
      routing states.  Then the MAG sends back the Update Notification
      Acknowledgement (UPA) message to the LMA for the notification of
      successful update of the HNP, related binding state, and routing
      state.  Then the LMA updates the routing and binding information
      corresponding to the MN to replace the old HNP with the new one.

   (2) HNP renumbering caused by the LMA switchover

   Since 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.

   The information of LMA is the basic configuration information of MAG.
   When the LMA changes, the related profile should be updated by the
   service provider.  In this way, the MAG initiates the registration to
   the new LMA as specified in [RFC5213].  When the HNP renumbering is
   caused in this case, the new HNP information is sent by the LMA
   during the new binding procedure.  Accordingly, the MAG withdraws the
   old HNP of the MN and announces the new HNP to the MN as like the
   case of the HNP is renumbered under the same LMA.

4.  Session Connectivity

   The HNP renumbering may cause the disconnection of the ongoing
   communications of the MN.  Basically, there are two modes to manage
   the session connectivity during the HNP renumbering.

   (1) Soft-mode

   The LMA will temporarily maintain the state of the old HNP during the
   HNP renumbering (after the UPA reception) in order to redirect the
   packets to the MN before the MN reconnects the ongoing session and
   notifies its new HoA to the Correspondent Node (CN).  This mode is
   aiming to reduce the packet loss during the HNP renumbering but the
   binding state corresponding to the old HNP should be marked for
   example as transient binding [RFC6058].  This temporary binding
   should only be used for the downwards packet transmission and the LMA
   should stop broadcasting the routing information about the old HNP if
   the old HNP is no longer anchored at this LMA.

   (2) Hard-mode

   If the HNP renumbering happens with the switchover of the LMA, the
   hard-mode is recommended to keep the protocol simple.  In this mode,
   the LMA deletes the binding state of the old HNP after it receives
   the UPA message from the MAG and the LMA silently discards the
   packets destined to the old HNP.

5.  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 [RFC5213] containing the new HNP and the Mobile Node
   Identifier Option [RFC4283] carrying identifier of MN are contained
   as Mobility Options of UPN.  The order of HNP Option and Mobile Node
   Identifier Option in the UPN message is not mandated in this draft.

   (2) UPA message

   The MAG sends this message in order to acknowledge that it has
   received an UPN message with the (A) flag set and to indicate the
   status after processing the message.  When the MAG did not
   successfully renumber the HNP which is required in the UPN message,
   the Status Code of 128 is set in the UPA message and the following
   operation of LMA is PMIPv6 service provider specific.

   (3) 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 [RFC4861].
   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.

   (4) DHCP Message

   When the DHCP is used in PMIPv6 to configure the addresses for the
   MN, new IPv6 address(es) (e.g., HoA) will be generated based on the
   new HNP and the related DHCP procedure is also triggered by the
   reception of UPN message [RFC3315].

6.  Other Issues

   In order to maintain the reachability of the MN, the Domain Name
   System (DNS) resource record corresponding to this MN may need to be
   updated when the HNP of MN changes [RFC3007].  However, this is
   beyond the scope of this document.

   The LMA must assign only an authorized HNP for the MN.

7.  Security Considerations

   The protection of UPN and UPA messages in this document follows
   [RFC5213] and [RFC7077].  This extension thus causes no further
   security problems for protecting of the messages.

   When the HNP renumbering is triggered, a new HNP has to be allocated
   to the MN.  The LMA must follow the proceduer of PMIPv6 to make sure
   that only an authorized HNP can be assigned for the MN.  In this way,
   LMA is ready to be the topological anchor point of the new HNP and
   the new HNP is for that MN's exclusive use.

8.  IANA Considerations

   This document presents no IANA considerations.

9.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC3007]  Wellington, B., "Secure Domain Name System (DNS) Dynamic
              Update", RFC 3007, DOI 10.17487/RFC3007, November 2000,
              <http://www.rfc-editor.org/info/rfc3007>.

   [RFC3315]  Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
              C., and M. Carney, "Dynamic Host Configuration Protocol
              for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July
              2003, <http://www.rfc-editor.org/info/rfc3315>.

   [RFC4283]  Patel, A., Leung, K., Khalil, M., Akhtar, H., and K.
              Chowdhury, "Mobile Node Identifier Option for Mobile IPv6
              (MIPv6)", RFC 4283, DOI 10.17487/RFC4283, November 2005,
              <http://www.rfc-editor.org/info/rfc4283>.

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              DOI 10.17487/RFC4861, September 2007,
              <http://www.rfc-editor.org/info/rfc4861>.

   [RFC5213]  Gundavelli, S., Ed., Leung, K., Devarapalli, V.,
              Chowdhury, K., and B. Patil, "Proxy Mobile IPv6",
              RFC 5213, DOI 10.17487/RFC5213, August 2008,
              <http://www.rfc-editor.org/info/rfc5213>.

   [RFC6275]  Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
              Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
              2011, <http://www.rfc-editor.org/info/rfc6275>.

   [RFC6463]  Korhonen, J., Ed., Gundavelli, S., Yokota, H., and X. Cui,
              "Runtime Local Mobility Anchor (LMA) Assignment Support
              for Proxy Mobile IPv6", RFC 6463, DOI 10.17487/RFC6463,
              February 2012, <http://www.rfc-editor.org/info/rfc6463>.

   [RFC7077]  Krishnan, S., Gundavelli, S., Liebsch, M., Yokota, H., and
              J. Korhonen, "Update Notifications for Proxy Mobile IPv6",
              RFC 7077, DOI 10.17487/RFC7077, November 2013,
              <http://www.rfc-editor.org/info/rfc7077>.

9.2.  Informative References

   [RFC6058]  Liebsch, M., Ed., Muhanna, A., and O. Blume, "Transient
              Binding for Proxy Mobile IPv6", RFC 6058,
              DOI 10.17487/RFC6058, March 2011,
              <http://www.rfc-editor.org/info/rfc6058>.

   [RFC6879]  Jiang, S., Liu, B., and B. Carpenter, "IPv6 Enterprise
              Network Renumbering Scenarios, Considerations, and
              Methods", RFC 6879, DOI 10.17487/RFC6879, February 2013,
              <http://www.rfc-editor.org/info/rfc6879>.

   [RFC7010]  Liu, B., Jiang, S., Carpenter, B., Venaas, S., and W.
              George, "IPv6 Site Renumbering Gap Analysis", RFC 7010,
              DOI 10.17487/RFC7010, September 2013,
              <http://www.rfc-editor.org/info/rfc7010>.

Authors' Addresses

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

   EMail: yan@cnnic.cn

   Jong-Hyouk Lee
   Sangmyung University
   31, Sangmyeongdae-gil, Dongnam-gu
   Cheonan  31066
   Republic of Korea

   EMail: jonghyouk@smu.ac.kr
   Xiaodong Lee
   CNNIC
   No.4 South 4th Street, Zhongguancun
   Beijing  100190
   China

   EMail: xl@cnnic.cn