Internet Engineering Task Force (IETF)                        A. Muhanna
Request for Comments: 5846                                     M. Khalil
Category: Standards Track                                       Ericsson
ISSN: 2070-1721                                            S. Gundavelli
                                                           K. Chowdhury
                                                                  Cisco
                                                              P. Yegani
                                                       Juniper Networks
                                                              June 2010


                 Binding Revocation for IPv6 Mobility

Abstract

  This document defines a binding revocation mechanism to terminate a
  mobile node's mobility session and the associated resources.  This
  mechanism can be used both with base Mobile IPv6 and its extensions,
  such as Proxy Mobile IPv6.  The mechanism allows the mobility entity
  which initiates the revocation procedure to request its peer to
  terminate either one, multiple or all specified Binding Cache
  entries.

Status of This Memo

  This is an Internet Standards Track document.

  This document is a product of the Internet Engineering Task Force
  (IETF).  It represents the consensus of the IETF community.  It has
  received public review and has been approved for publication by the
  Internet Engineering Steering Group (IESG).  Further information on
  Internet Standards is available in Section 2 of RFC 5741.

  Information about the current status of this document, any errata,
  and how to provide feedback on it may be obtained at
  http://www.rfc-editor.org/info/rfc5846.















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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
  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.

  This document may contain material from IETF Documents or IETF
  Contributions published or made publicly available before November
  10, 2008.  The person(s) controlling the copyright in some of this
  material may not have granted the IETF Trust the right to allow
  modifications of such material outside the IETF Standards Process.
  Without obtaining an adequate license from the person(s) controlling
  the copyright in such materials, this document may not be modified
  outside the IETF Standards Process, and derivative works of it may
  not be created outside the IETF Standards Process, except to format
  it for publication as an RFC or to translate it into languages other
  than English.

























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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


Table of Contents

  1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
  2.  Conventions and Terminology  . . . . . . . . . . . . . . . . .  4
    2.1.  Conventions Used in This Document  . . . . . . . . . . . .  4
    2.2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  4
  3.  Binding Revocation Protocol and Use Cases Overview . . . . . .  5
    3.1.  Binding Revocation Protocol  . . . . . . . . . . . . . . .  5
    3.2.  MIPv6 and DSMIP6 Use Case  . . . . . . . . . . . . . . . .  6
    3.3.  Multiple Care-of Addresses (MCoA) Use Case . . . . . . . .  7
    3.4.  Proxy MIPv6 Use Case . . . . . . . . . . . . . . . . . . .  8
      3.4.1.  Local Mobility Anchor Initiates PMIPv6 Revocation  . .  9
      3.4.2.  Mobile Access Gateway Revokes Bulk PMIPv6 Bindings . . 10
  4.  Binding Revocation Messages over IPv4 Transport Network  . . . 10
  5.  Binding Revocation Message . . . . . . . . . . . . . . . . . . 11
    5.1.  Binding Revocation Indication Message  . . . . . . . . . . 13
    5.2.  Binding Revocation Acknowledgement Message . . . . . . . . 16
  6.  Binding Revocation Process Operation . . . . . . . . . . . . . 18
    6.1.  Sending Binding Revocation Message . . . . . . . . . . . . 18
      6.1.1.  Sending Binding Revocation Indication  . . . . . . . . 18
      6.1.2.  Sending Binding Revocation Acknowledgement . . . . . . 19
    6.2.  Receiving Binding Revocation Message . . . . . . . . . . . 20
      6.2.1.  Receiving Binding Revocation Indication  . . . . . . . 20
      6.2.2.  Receiving Binding Revocation Acknowledgement . . . . . 21
    6.3.  Retransmission of Binding Revocation Indication  . . . . . 22
  7.  Home Agent Operation . . . . . . . . . . . . . . . . . . . . . 22
  8.  Local Mobility Anchor Operation  . . . . . . . . . . . . . . . 23
    8.1.  Sending Binding Revocation Indication  . . . . . . . . . . 23
    8.2.  Receiving Binding Revocation Indication  . . . . . . . . . 27
  9.  Mobile Access Gateway Operation  . . . . . . . . . . . . . . . 29
    9.1.  Receiving Binding Revocation Indication  . . . . . . . . . 29
    9.2.  Sending Binding Revocation Indication  . . . . . . . . . . 31
  10. Mobile Node Operation  . . . . . . . . . . . . . . . . . . . . 32
  11. Protocol Configuration Variables . . . . . . . . . . . . . . . 34
  12. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 34
  13. Security Considerations  . . . . . . . . . . . . . . . . . . . 36
  14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 37
  15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 37
    15.1. Normative References . . . . . . . . . . . . . . . . . . . 37
    15.2. Informative References . . . . . . . . . . . . . . . . . . 38











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1.  Introduction

  In the case of Mobile IPv6 and for administrative reasons, sometimes
  it becomes necessary to inform the mobile node that its registration
  has been revoked and the mobile node is no longer able to receive IP
  mobility service for its Home Address.  A similar Mobile IPv4
  registration revocation mechanism [RFC3543] has been specified by the
  IETF for providing a revocation mechanism for sessions that were
  established using Mobile IPv4 registration [RFC3344].

  This document specifies a binding revocation mechanism that can be
  used to revoke a mobile node's mobility session(s).  The same
  mechanism can be used to revoke bindings created using Mobile IPv6
  [RFC3775] or any of its extensions, e.g., Proxy Mobile IPv6
  [RFC5213].  The proposed revocation mechanism uses a new Mobility
  Header (MH) type 16 for revocation signaling that is applicable to
  Mobile IPv6 [RFC3775] and Proxy Mobile IPv6 [RFC5213] and can be used
  by any two IP mobility entities.  As an example, this mechanism
  allows a local mobility anchor (LMA), involved in providing IP
  mobility services to a mobile node, to notify the mobile access
  gateway (MAG) of the termination of that mobile node binding
  registration.  In another example, a mobile access gateway can use
  this mechanism to notify its local mobility anchor peer with a bulk
  termination of all or a subset of proxy mobile IPv6 (PMIPv6) bindings
  that are registered with the local mobility anchor and currently
  being served by the mobile access gateway.  Any mobility entity is
  allowed to revoke only the registration of those mobile node(s)
  mobility sessions that are currently registered with it.

2.  Conventions and Terminology

2.1.  Conventions Used in This Document

  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].

2.2.  Terminology

  All the general mobility related terminology and abbreviations are to
  be interpreted as defined in the Mobile IPv6 [RFC3775], Proxy Mobile
  IPv6 [RFC5213] and IPv4 Support for Proxy Mobile IPv6 [RFC5844]
  specifications.  The following terms are used in this specification.








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  Initiator

     The mobility node that initiates the binding revocation procedure
     by sending a Binding Revocation Indication message to its peer,
     e.g., home agent, local mobility anchor, or mobile access gateway.

  Responder

     The mobility node that receives the Binding Revocation Indication
     message and responds with a Binding Revocation Acknowledgement
     message, e.g., mobile node, mobile access gateway, or local
     mobility anchor.

3.  Binding Revocation Protocol and Use Cases Overview

  This specification specifies a generic binding revocation mechanism
  where a mobility node can communicate to the mobile node or another
  mobility node the identity of the mobile node registration binding
  that is being terminated.  In the case when this mechanism is used
  for bulk termination or multiple bindings, the identities of these
  bindings are communicated to the mobile node or mobility node using
  the same generic mechanism.  The following subsections present the
  protocol overview and applicable use cases.

3.1.  Binding Revocation Protocol

  In the case of Mobile IPv6, if the home network decides to terminate
  the service of the mobile node, the home agent sends a Binding
  Revocation Indication (BRI) message to the mobile node.  The home
  agent includes the home address (HoA) of the mobile node in the Type
  2 routing header as specified in [RFC3775] to indicate the impacted
  mobile node binding.  In the case of Dual Stack Mobile IPv6 (DSMIPv6)
  [RFC5555], the home agent may include the IPv4 Home Address option
  with the home IPv4 address assigned by the mobile node.
  Additionally, if the mobile node registered multiple care-of
  addresses [RFC5648], the home agent includes the Binding Identifier
  (BID) option(s) in the Binding Revocation Indication message to
  identify which binding is being revoked.  When the mobile node
  receives a Binding Revocation Indication message with its HoA
  included in the Type 2 routing header, the mobile node responds by
  sending a Binding Revocation Acknowledgement (BRA) message.

  Similarly, in the case of Proxy Mobile IPv6 [RFC5213], the revocation
  procedure can be initiated by the local mobility anchor by sending a
  Binding Revocation Indication message to communicate the termination
  of a mobile node registration binding to the mobile access gateway.
  In this case, the local mobility anchor includes the mobile node Home
  Network Prefix (MN-HNP) option [RFC5213] and the MN-ID option



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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


  [RFC4283] to indicate to the mobility access gateway the identity of
  the PMIPv6 binding that needs to be terminated.  When the mobile
  access gateway receives the Binding Revocation Indication message,
  the mobile access gateway responds to the local mobility anchor by
  sending a Binding Revocation Acknowledgement message.

  On the other hand, the mobile access gateway usually sends a de-
  registration message by sending a Proxy Binding Update with a
  lifetime of zero to indicate to the local mobility anchor of the
  termination of the PMIPv6 mobile node binding registration.  In this
  case, the mobile access gateway includes the MN-HNP option, the MN-ID
  option, and all other required mobility options as per [RFC5213] in
  order for the local mobility anchor to identify the mobile node
  PMIPv6 binding.  Additionally, in the case when the mobile access
  gateway communicates a bulk termination of PMIPv6 mobility sessions,
  the mobile access gateway sends a Binding Revocation Indication
  message with the Global (G) bit set and includes the mobile access
  gateway identity in the MN-ID option, see Section 9.2 and
  Section 8.2.  When the local mobility anchor receives such a Binding
  Revocation Indication message, it ensures that the mobile access
  gateway is authorized to send such a bulk termination message, see
  Section 13, and then processes the Binding Revocation Indication
  message accordingly.  If the local mobility anchor processes the
  Binding Revocation Indication message successfully, the local
  mobility anchor responds to the mobile access gateway by sending
  Binding Revocation Acknowledgement message.

  In any of the above cases, the initiator of the binding revocation
  procedure, e.g., home agent, local mobility anchor, or mobile access
  gateway, uses the Revocation Trigger field in the Binding Revocation
  Indication message to indicate to the receiving node the reason for
  initiating the revocation procedure.

3.2.  MIPv6 and DSMIP6 Use Case

  The binding revocation mechanism is applicable to Mobile IPv6 and
  DSMIPv6 session(s) when the home agent needs to inform the mobile
  node that its binding registration has been revoked, e.g., for an
  administrative reason.  This mechanism enables the user or the mobile
  node to react to the revocation, e.g., reinstate its interrupted
  Mobile IPv6 services.

  In this case, the home agent sends a Binding Revocation Indication
  message to indicate to the mobile node that its current mobile IPv6
  (MIPv6) binding has been revoked and it is no longer able to receive
  IP mobility service.  The home agent includes the HoA in a Type 2
  routing header as used in [RFC3775] and sets the Revocation Trigger
  field to a proper value, e.g., Administrative Reason.  In the case of



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  a DSMIPv6 session, the home agent may additionally include the
  mobile-node-assigned IPv4 Home Address in the IPv4 Home Address
  option.  When the mobile node receives the Binding Revocation
  Indication message, it sends a Binding Revocation Acknowledgement
  message to the home agent.  Figure 1 illustrates the message
  sequencing when a home agent revokes a mobile node binding
  registration.

        MN                                         HA
        |                                           |
        |           HoA in Type 2 Routing Hdr       |
        |<<<------------...  +  ...-----------------|
        |      BRI [seq.#, Revocation Trigger]      |
        |                                           |
        |                                           |
        | BRA (HoA in Dest. Option)[seq.#, Status]  |
        |---------------------------------------->>>|
        |                                           |
        |                                           |

     Figure 1: Home Agent Revokes a Mobile Node Binding Registration

3.3.  Multiple Care-of Addresses (MCoA) Use Case

  In the case of multiple care-of address registrations [RFC5648], the
  home agent maintains a different binding for each care-of address and
  home address pair.  These bindings are also indexed and identified
  during the mobile node registration using a BID mobility option.  The
  HA may revoke one or multiple bindings for the same mobile node home
  address.

  If the home agent revokes a single binding for a mobile node with
  multiple care-of address registrations, the home agent sends a
  Binding Revocation Indication message to the mobile node with the
  corresponding BID option included.  If more than one of the mobile
  node registered care-of addresses needs to be revoked, the home agent
  includes all the corresponding BID options in the same Binding
  Revocation Indication message.  Figure 2 illustrates the message flow
  when the home agent revokes two registered care-of addresses for the
  same mobile node in a single Binding Revocation Indication message.











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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


                                                   HA Binding Cache
                                                   ================
                                                   MN-BID1 [CoA1+HoA]
  MN                                           HA  MN-BID2 [CoA2+HoA]
   |                                            |  MN-BID3 [CoA3+HoA]
   |                                            |  MN-BID4 [CoA4+HoA]
   |             HoA in Type 2 Routing Hdr      |
   |<<<<--------------  +  ---------------------|
   |     BRI [seq.#, R. Trigger, BID1, BID4]    |
   |                                            |
   |                                            |
   | BRA (HoA in Dest. Option) [seq.#, Status]  |
   |---------------------------------------->>>>|
   |                                            |
   |                                            |

   Figure 2: Home Agent Revokes MN's Specific Care-of Address Bindings

  Additionally, the home agent may revoke all of the mobile node
  registered bindings by sending a BRI message without including any
  BID options while the HoA is included in the Type 2 routing header.
  Figure 1 illustrates the message flow when the home agent revokes all
  registered care-of address bindings for a mobile node in a single
  Binding Revocation Indication message.

3.4.  Proxy MIPv6 Use Case

  Since the mobile node does not participate in the mobility mechanism
  in the case of PMIPv6, there are many scenarios where the Binding
  Revocation mechanism is needed to clean resources and make sure that
  the mobility entities, i.e., mobile access gateway and local mobility
  anchor, are always synchronized with respect to the status of the
  existing PMIPv6 bindings.  The binding revocation mechanism is
  generic enough that it can be used for all Proxy Mobile IPv6
  scenarios that follow the [RFC5213] and [RFC5844] specifications.

  When the mobile access gateway receives a Binding Revocation
  Indication message as in Section 9.1, the mobile access gateway sends
  a Binding Revocation Acknowledgement message to the local mobility
  anchor following the rules described in Section 6.1.2.  Similarly, if
  the local mobility anchor receives a Binding Revocation Indication
  message, the local mobility anchor responds to the mobile access
  gateway by sending a Binding Revocation Acknowledgement message.








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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


3.4.1.  Local Mobility Anchor Initiates PMIPv6 Revocation

  The local mobility anchor may send a Binding Revocation Indication
  message with the appropriate revocation trigger value to the mobile
  access gateway that hosts a specific PMIPv6 binding to indicate that
  the mobile node binding has been terminated and the mobile access
  gateway can clean up the applicable resources.  When the mobile
  access gateway receives a Binding Revocation Indication message, the
  mobile access gateway identifies the respective binding and it sends
  a Binding Revocation Acknowledgement message to the local mobility
  anchor.  In this case, the mobile access gateway could terminate the
  IPv6 or IPv4 mobility session on the access link and notify the
  mobile node as in Section 9.1.

  As an example, Figure 3, illustrates the message sequence for
  revoking a mobile node binding at the source mobile access gateway
  during the mobile node inter-MAG handover.  During the inter-MAG
  handover, the mobile node moves from the source MAG to the target
  MAG.  The target MAG sends a Proxy Binding Update with the new
  care-of address to the local mobility anchor to update the mobile
  node's point of attachment.  Since the mobile node binding at the
  local mobility anchor points to the source MAG and upon receiving the
  Proxy Binding Update from the target MAG, the local mobility anchor
  updates the MN Binding Cache entry (BCE) and sends a Proxy Binding
  Acknowledgement to the target MAG.  The local mobility anchor can
  send a Binding Revocation Indication message with the appropriate
  revocation trigger value, e.g., inter-MAG handover - different Access
  Types, to the source MAG in order to clean up the applicable
  resources reserved for the specified mobile node binding.  The source
  mobile access gateway acknowledges the Binding Revocation Indication
  message by sending a Binding Revocation Acknowledgement message to
  indicate the success or failure of the termination of the mobile
  node's binding.

  The process identified above can also be used by the local mobility
  anchor in scenarios other than the inter-MAG handover with the proper
  revocation trigger value to indicate to the peer mobile access
  gateway that a specific PMIPv6 binding or bindings have been revoked.













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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


            oldMAG       newMAG                          LMA
              |             |                            |
              |             |        PBU                 |
              |             |--------------------------->|
              |             |                      PBU triggers
              |             |                   BRI Msg to oldMAG
              |             |                            |
              |             |        PBA                 |
              |             |<---------------------------|
              |             |                            |
              |             |                            |
              |    BRI [seq.#, R. Trigger, P bit, NAI]   |
              |<-----------------------------------------|
              |             |                            |
              |             |                            |
              |             |                            |
              |             |                            |
              |        BRA [seq.#, Status, P bit]        |
              |----------------------------------------->|
              |             |                            |
              |             |                            |

   Figure 3: LMA Revokes an MN Registration During Inter-MAG Handover

  In addition, the local mobility anchor can send a Binding Revocation
  Indication message to indicate that all bindings that are hosted by
  the peer mobile access gateway and registered with the local mobility
  anchor are being revoked by setting the Global (G) bit as described
  in Section 8.1.

3.4.2.  Mobile Access Gateway Revokes Bulk PMIPv6 Bindings

  The mobile access gateway sends a BRI message with the Global (G) bit
  set and the Revocation Trigger field set to "Per-Peer Policy" to
  indicate that all mobility bindings that are registered at the local
  mobility anchor and attached to the mobile access gateway are being
  revoked as in Section 9.2.  When the local mobility anchor receives
  this Binding Revocation Indication message from the specified mobile
  access gateway, the local mobility anchor first checks if the mobile
  access gateway is authorized to use global revocations, then it
  responds with the appropriate status code by sending a Binding
  Revocation Acknowledgement message as in Section 6.1.2.

4.  Binding Revocation Messages over IPv4 Transport Network

  In some deployments, the network between the mobile access gateway
  and the local mobility anchor may only support IPv4 transport.
  Another case is when a mobile node that supports client mobile IPv6



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  roams to an access network where only IPv4 addressing and transport
  is supported.  In this case, the mobile node is required to register
  an IPv4 home address with its home agent using a mobile IPv6 Binding
  Update message.

  If the Proxy Binding Update and Proxy Binding Acknowledgement
  messages or the Binding Update and Binding Acknowledgement messages
  are sent using UDP encapsulation [RFC5844] [RFC5555], then the
  Binding Revocation Messages are sent using the same UDP
  encapsulation.  The same UDP source and destination port numbers and
  IPv4 addresses used for exchanging the Proxy Binding Update and Proxy
  Binding Acknowledgement or the Binding Update and Binding
  Acknowledgement messages MUST be used when transporting Binding
  Revocation Messages over IPv4 using UDP encapsulation.  For example,
  the source UDP port number, the destination UDP port number, the
  source IPv4 address, and the destination IPv4 address of the Binding
  Revocation Indication message are set to the destination UDP port
  number, the source UDP port number, destination IPv4 address, and
  source IPv4 address of the latest received and successfully processed
  Proxy Binding Update or Binding Update message, respectively.  For
  more details on tunneling Proxy Mobile IPv6 and Mobile IPv6 signaling
  messages over IPv4, see [RFC5844] and [RFC5555], respectively.

5.  Binding Revocation Message

  This section defines the Binding Revocation Message format using an
  MH Type 16 as illustrated in Figure 4.  The value in the Binding
  Revocation Type field defines whether the Binding Revocation Message
  is a Binding Revocation Indication or Binding Revocation
  Acknowledgement.  If the Binding Revocation Type field is set to 1,
  the Binding Revocation Message is a Binding Revocation Indication as
  in Section 5.1.  However, if the value is 2, it is a Binding
  Revocation Acknowledgement message as in Section 5.2.

      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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Payload Proto |  Header Len   |   MH Type     |   Reserved    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |           Checksum            |  B.R. Type    |               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+               +
      |                                                               |
      .            Binding Revocation Message Data                    .
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 4: Binding Revocation Message




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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


  Payload Proto

     8-bit selector.  See [RFC3775] for more details.

  Header Len

     8-bit unsigned integer.  Representing the length of the Mobility
     Header in units of 8 octets, excluding the first 8 octets.  See
     [RFC3775] for more details.

  MH Type

     16, which identifies the mobility message as a Binding Revocation
     Message.

  Reserved

     8-bit field reserved for future use.  The value MUST be
     initialized to zero by the sender and MUST be ignored by the
     receiver.

  Checksum

     16-bit unsigned integer.  This field contains the checksum of the
     Mobility Header.  The checksum is calculated as described in
     [RFC3775].

  Binding Revocation Type

     8-bit unsigned integer.  It defines the type of the Binding
     Revocation Message.  It can be assigned one of the following
     values:

         0  Reserved

         1  Binding Revocation Indication

         2  Binding Revocation Acknowledgement

         All other values are unassigned

  Binding Revocation Message Data

     The Binding Revocation Message Data follows the Binding Revocation
     Message format that is defined in this document for the specified
     value in the Binding Revocation Type field.  In this document, it
     is either a Binding Revocation Indication as in Section 5.1 or
     Binding Revocation Acknowledgement as in Section 5.2.



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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


5.1.  Binding Revocation Indication Message

  The Binding Revocation Indication (BRI) message is a Binding
  Revocation Message that has an MH type 16 and a Binding Revocation
  Type value of 1.  It is used by the initiator to inform the responder
  of the identity of a specific binding or bindings for which IP
  mobility service are being revoked.  Binding Revocation Indication
  message is sent as described in Sections 7, 8.1, and 9.2.

  When the value 1 is indicated in the Binding Revocation Type field of
  the Binding Revocation Message, the format of the Binding Revocation
  Message Data follows the Binding Revocation Indication message as in
  Figure 5

      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
                                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                      | B.R. Type = 1 |  R. Trigger   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |          Sequence #           |P|V|G|       Reserved          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      .                                                               .
      .                        Mobility options                       .
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

             Figure 5: Binding Revocation Indication Message

  Revocation Trigger

     8-bit unsigned integer indicating the event that triggered the
     initiator to send the BRI message.  The Per-MN Revocation Trigger
     values are less than 128.  The Per-MN Revocation Trigger is used
     when the BRI message intends to revoke one or more bindings for
     the same mobile node.  The Global Revocation Trigger values are
     greater than 128 and less than 250 and used in the BRI message
     when the Global (G) bit is set for global revocation.  The values
     250-255 are reserved for testing purposes only.  The following
     Revocation Trigger values are currently defined:

     Per-MN Revocation Trigger Values:
         0  Unspecified
         1  Administrative Reason
         2  Inter-MAG Handover - same Access Type
         3  Inter-MAG Handover - different Access Type
         4  Inter-MAG Handover - Unknown
         5  User-Initiated Session(s) Termination



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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


         6  Access Network Session(s) Termination
         7  Possible Out-of-Sync BCE State

     Global Revocation Trigger Values:
         128  Per-Peer Policy
         129  Revoking Mobility Node Local Policy

     Reserved Revocation Trigger Values:
         250-255 Reserved For Testing Purposes only
         All other values are Reserved

  Sequence Number

     A 16-bit unsigned integer used by the initiator to match a
     returned Binding Revocation Acknowledgement with this Binding
     Revocation Indication.  This sequence number could be a random
     number.  At any time, implementations MUST ensure there is no
     collision between the sequence numbers of all outstanding Binding
     Revocation Indication Messages.

  Proxy Binding (P)

     The Proxy Binding (P) bit is set by the initiator to indicate that
     the revoked binding(s) is a PMIPv6 binding.

  IPv4 HoA Binding Only (V)

     The IPv4 HoA Binding Only (V) bit is set by the initiator, home
     agent, or local mobility anchor to indicate to the receiving
     mobility entity the termination of the IPv4 Home Address binding
     only as in Sections 7 and 8.1.

  Global (G)

     The Global (G) bit is set by the initiator, LMA or MAG, to
     indicate the termination of all Per-Peer mobility Bindings or
     Multiple Bindings that share a common identifier(s) and are served
     by the initiator and responder as in Sections 8.1 and 9.2.

  Reserved

     These fields are unused.  They MUST be initialized to zero by the
     sender and MUST be ignored by the receiver.

  Mobility Options

     A variable-length field of such length that the complete Mobility
     Header is an integer multiple of 8 octets long.  This field



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     contains zero or more TLV-encoded mobility options.  This document
     does not define any new mobility option.  The receiver MUST ignore
     and skip any options that it does not understand.  These mobility
     options are used by the responder to identify the specific binding
     or bindings that the initiator is requesting be revoked.

  The following options are valid in a Binding Revocation Indication:

  o  Home Network Prefix option [RFC5213].  This option MAY be used
     only when the (P) bit is set.  This option MUST be present when
     the BRI is used to revoke a single Proxy MIPv6 Binding Cache
     entry.

  o  Mobile Node Identifier option [RFC4283].  This option MUST be
     present when the (P) bit is set.  Additionally, if the Global (G)
     bit is set by the mobile access gateway, this option MUST carry
     the MAG identity.  In this specification, only the Mobile Node
     Identifier option with subtype 1 is required and other subtypes
     are currently not supported.

  o  Binding Identifier mobility option [RFC5648].  This option MUST be
     present if the initiator requests to terminate one binding of a
     multiple care-of address bindings for the same mobile node.  The
     initiator may include more than one of the BID mobility options.

  o  IPv4 Home Address option, which contains the mobile node home IPv4
     address [RFC5555].  This option MUST only be included when the
     IPv4 HoA Binding only (V) bit is set and the (P) bit is cleared.

  o  IPv4 Home Address Request option, which contains the mobile node
     proxy home IPv4 address [RFC5844].  This option MUST only be
     included when the IPv4 HoA Binding only (V) and the (P) bits are
     set.

  o  Alternate Care-of Address mobility option [RFC3775].  According to
     [RFC5213], the mobile access gateway is allowed to include this
     option in the Proxy Binding Update to indicate the proxy care-of
     address of the mobile node mobility session.  This option MAY be
     included to indicate the proxy care-of address of the mobile
     node's binding that is being revoked.  In the case when the Global
     (G) bit is set, this option identifies all mobility bindings that
     share the same proxy care-of address.

  If no mobility options are present in this message, 4 octets of
  padding are necessary and the Header Len field of the Binding
  Revocation Message will be set to 1.





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5.2.  Binding Revocation Acknowledgement Message

  The Binding Revocation Acknowledgement (BRA) message is a Binding
  Revocation Message that has an MH type 16 and a Binding Revocation
  Type value of 2.  It is used to acknowledge the receipt of a Binding
  Revocation Indication message described in Section 5.1.  This packet
  is sent as described in Section 6.1.2.

  When the value 2 is indicated in the Binding Revocation Type field of
  the Binding Revocation Message, the format of the Binding Revocation
  Message Data follows the Binding Revocation Acknowledgement message
  as in Figure 6.

      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
                                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                      | B.R. Type = 2 |    Status     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |            Sequence #         |P|V|G|       Reserved          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      .                                                               .
      .                        Mobility options                       .
      .                                                               .
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

          Figure 6: Binding Revocation Acknowledgement Message

  Status  8-bit unsigned integer indicating the result of processing
     the Binding Revocation Indication message by the responder.
     Values of the Status field less than 128 indicate that the Binding
     Revocation Indication was processed successfully by the responder.
     Values greater than or equal to 128 indicate that the Binding
     Revocation Indication was rejected by the responder.  The
     following Status values are currently defined:

           0  success
           1  partial success
         128  Binding Does NOT Exist
         129  IPv4 Home Address Option Required
         130  Global Revocation NOT Authorized
         131  Revoked Mobile Nodes Identity Required
         132  Revocation Failed - MN is Attached
         133  Revocation Trigger NOT Supported
         134  Revocation Function NOT Supported
         135  Proxy Binding Revocation NOT Supported




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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


  Sequence Number

     The sequence number in the Binding Revocation Acknowledgement is
     copied from the Sequence Number field in the Binding Revocation
     Indication.  It is used by the initiator, e.g., HA, LMA, MAG, in
     matching this Binding Revocation Acknowledgement with the
     outstanding Binding Revocation Indication.

  Proxy Binding (P)

     The Proxy Binding (P) bit is set if the (P) bit is set in the
     corresponding Binding Revocation Indication message.

  IPv4 HoA Binding Only (V)

     The IPv4 HoA Binding Only (V) bit is set if the (V) bit is set in
     the corresponding Binding Revocation Indication message.

  Global (G)

     The Global (G) bit is set if the (G) bit is set in the
     corresponding Binding Revocation Indication message.

  Reserved

     These fields are unused.  They MUST be initialized to zero by the
     sender and MUST be ignored by the receiver.

  Mobility Options

     A variable-length field of such length that the complete Mobility
     Header is an integer multiple of 8 octets long.  This field
     contains zero or more TLV-encoded mobility options.  In the case
     when the Status field is set to success, no mobility option is
     required.  The mobility option(s) is usually used to communicate
     information of the bindings that failed the revocation procedure.

  The following mobility options are valid in a Binding Revocation
  Acknowledgement:

  o  Home Network Prefix option [RFC5213].  This option MAY be included
     only when the (P) bit is set.

  o  Mobile Node Identifier Option [RFC4283].  This option MAY be
     included when the (P) bit is set.  This option SHOULD be included
     if the Home Network Prefix option is included.





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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


  o  Binding Identifier mobility option [RFC5648].  The responder MAY
     include this option to indicate the specific BID that failed the
     revocation procedure.

  If no options are present in this message, 4 octets of padding are
  necessary and the Header Len field of the Binding Revocation Message
  will be set to 1.

6.  Binding Revocation Process Operation

  The following subsections describe the details of the generic binding
  revocation process as used by the different mobility entities.

6.1.  Sending Binding Revocation Message

  When sending a Binding Revocation message, the initiator constructs
  the packet as it would do with any other Mobility Header with the
  exception of setting the MH Type field to 16.

  The Binding Revocation Message MUST be protected using the same
  underlying security association, e.g., IPsec, that is being used
  between the two peers to protect the mobile node's Mobile IPv6 and
  its extensions binding registration signaling.  If IPsec is not used
  as the underlying security mechanism to protect the binding
  registration signaling, the used underlying security mechanism MUST
  provide protection against all identified security threats as
  described under "Security Considerations" in [RFC3775] and [RFC5213].

6.1.1.  Sending Binding Revocation Indication

  The initiator MUST construct the Binding Revocation Message Data
  following the format of the Binding Revocation Indication message as
  described in Section 5.1 and the following:

  o  The initiator MUST set the Sequence Number field to a valid
     sequence number for Binding Revocation.  Since sending a Binding
     Revocation Indication message is not done on a regular basis, a
     16-bit Sequence Number field is large enough to allow the
     initiator to match the Binding Revocation Acknowledgement to the
     associated Binding Revocation Indication using the Sequence Number
     field only.

  o  If the initiator is revoking a binding that was created using
     proxy MIPv6 registration, the initiator MUST set the Proxy Binding
     (P) bit.






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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


  o  If the initiator is sending the Binding Revocation Indication
     message to revoke multiple mobility sessions, the initiator MUST
     set the Global (G) bit.  In this case, the initiator MUST set the
     Revocation Trigger field to a valid value from the list of Global
     Revocation Triggers.

  o  If the initiator is sending the Binding Revocation Indication
     message with the Global (G) bit cleared, the initiator MUST set
     the Revocation Trigger field to a valid value from the list of
     Per-MN Revocation Triggers.

  o  If the initiator is sending the Binding Revocation Indication
     message to indicate the revocation of the mobile node IPv4 HoA
     Binding Only, the initiator MUST set the (V) bit.  In this case,
     the initiator MUST include either the IPv4 Home Address option or
     the IPv4 Home Address Request option in the BRI to identify the
     IPv4 HoA that is being revoked.

6.1.2.  Sending Binding Revocation Acknowledgement

  The responder MUST send a Binding Revocation Acknowledgement message
  to indicate the receipt and the status of processing of the
  corresponding Binding Revocation Indication message as follows:

  o  Whenever the Binding Revocation Indication is discarded, e.g., as
     described in Section 6.2, a Binding Revocation Acknowledgement
     MUST NOT be sent.  Otherwise, the treatment depends on the
     following rules.

  o  If the responder accepts the Binding Revocation Indication
     message, the responder MUST send a successful Binding Revocation
     Acknowledgement with an appropriate status code.

  o  If the responder rejects the Binding Revocation Indication
     message, the responder MUST send a Binding Revocation
     Acknowledgement with an appropriate failure status code.

  If the Source Address field of the IPv6 header that carried the
  Binding Revocation Indication message does not contain a unicast
  address, the Binding Revocation Indication packet MUST be silently
  discarded.

  When the responder acknowledges the received Binding Revocation
  Indication message, the responder MUST construct the Binding
  Revocation Message Data following the format of the Binding
  Revocation Acknowledgement message as described in Section 5.2 and
  the following:




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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


  o  The responder MUST set the Sequence Number field by copying the
     value from the Sequence Number field of the received Binding
     Revocation Indication.

  o  The responder MUST set the Status field to a valid value that
     reflects the status of the processing of the received Binding
     Revocation Indication message.

  o  If the (P) bit is set in the received Binding Revocation
     Indication, the responder MUST set the (P) bit in the Binding
     Revocation Acknowledgement.

  o  If the Global (G) bit is set in the received Binding Revocation
     Indication, the responder MUST set the Global (G) bit in the
     Binding Revocation Acknowledgement.

  o  If the IPv4 HoA Binding Only (V) bit is set in the received
     Binding Revocation Indication, the responder MUST set the (V) bit
     in the Binding Revocation Acknowledgement.

  o  The destination IP address of the IPv6 packet of the Binding
     Revocation Acknowledgement is set to the source IP address of the
     received Binding Revocation Indication.

6.2.  Receiving Binding Revocation Message

  When receiving a Binding Revocation Message, the responder MUST
  verify the Mobility Header as described in Section 9.2. of [RFC3775].
  If the packet is dropped due to failing any of the Mobility Header
  test checks, the responder MUST follow the processing rules as in
  Section 9.2 of [RFC3775].  If the responder does not support the
  Binding Revocation Indication message and does not recognize the MH
  type 16, it sends a Binding Error message with the Status field set
  to 2 as described in [RFC3775].

  Upon receiving a packet carrying a Binding Revocation Message, BRI or
  BRA, the receiving mobility entity MUST verify that the packet was
  received protected by the security association that is being used to
  protect the binding registration and Binding Revocation signaling
  between the two peers, e.g., an IPsec Security Association (SA).

6.2.1.  Receiving Binding Revocation Indication

  When the responder receives a packet carrying a Binding Revocation
  Indication message that was successfully processed as in Section 6.2,
  the responder, in addition, processes the message as follows:





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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


  o  The responder MUST validate that the Binding Revocation Indication
     is formatted as in Section 5.1.

  o  If the Revocation Trigger field is set to a value that the
     responder does not support, the responder SHOULD reject the
     Binding Revocation Indication message using status code
     "Revocation Trigger NOT Supported".

  o  If the Revocation Trigger value is NOT allowed with the Binding
     Revocation Indication message intent, e.g., the Global (G) bit is
     set and the Revocation Trigger field value is Per-MN-specific, the
     responder SHOULD reject the Binding Revocation Indication message
     using status code "Revocation Function NOT Supported".

  o  If the responder failed to identify the mobile node(s) bindings as
     identified in the Binding Revocation Indication message, the
     responder MUST reject the BRI using status code "Binding Does NOT
     Exist".

6.2.2.  Receiving Binding Revocation Acknowledgement

  When the initiator receives a packet carrying a Binding Revocation
  Acknowledgement message that was successfully processed as in
  Section 6.2, the initiator, in addition, processes the message and
  examines the Status field as follows:

  o  The initiator MUST validate that the sequence number in the
     Sequence Number field matches the sequence number of an
     outstanding Binding Revocation Indication that was sent by the
     initiator.  If the sequence number does not match a sequence
     number of any of the outstanding Binding Revocation Indication
     messages, the initiator MUST silently discard the message but MAY
     log the event.

  o  If the Status field indicates that the Binding Revocation
     Indication was processed successfully, the initiator MUST delete
     the current timer and the mobile node(s) binding(s) and all
     associated resources.

  o  If the Status field indicates any value other than success, the
     initiator SHOULD examine any mobility options included in the
     Binding Revocation Acknowledgement.  In this case, it is based on
     the initiator local policy how to handle the mobile node binding.
     The initiator MAY log the appropriate event to reflect the
     received status.






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6.3.  Retransmission of Binding Revocation Indication

  If the initiator does not receive a Binding Revocation
  Acknowledgement in response to the outstanding Binding Revocation
  Indication before the InitMINDelayBRIs timer expires, the initiator,
  e.g., LMA, SHOULD retransmit the same BRI message up to the
  BRIMaxRetriesNumber as defined in Section 11.

  The retransmissions by the initiator MUST use an exponential back-off
  process in which the timeout period is doubled upon each
  retransmission, until either the initiator receives a response or the
  timeout period reaches the value MAX_BRACK_TIMEOUT.  The initiator
  MAY continue to send these messages at this slower rate up to the
  BRIMaxRetriesNumber.

  If the initiator does not receive a Binding Revocation
  Acknowledgement message after the BRIMaxRetriesNumber of retransmits
  have been sent, the initiator SHOULD clean up all resources
  associated with this mobile node binding.  The initiator may log the
  event.

7.  Home Agent Operation

  To terminate a mobile node registration and its current binding with
  the home agent, the home agent sends a packet to the mobile node
  containing a Binding Revocation Indication, with the packet
  constructed as follows:

  o  The Revocation Trigger field MUST be set to indicate to the mobile
     node the reason for revoking its IP mobility binding with the home
     agent.  The Revocation Trigger may be used by the mobile node to
     take further steps if necessary.

  o  The Binding Revocation Indication MUST be sent using a Type 2
     routing header that contains the mobile node's registered IPv6
     home address for the binding being revoked.

  o  The care-of address for the binding MUST be used as the
     destination address in the packet's IPv6 header.

  o  If the home agent needs to only revoke the mobile node's IPv4 home
     address binding, the home agent MUST set the IPv4 HoA Binding Only
     (V) bit and MUST include the mobile node's registered IPv4 home
     address that is being revoked in the IPv4 Home Address option.

  When the home agent sends a Binding Revocation Indication to the
  mobile node, the home agent sets a flag in the mobile node BCE to
  indicate that revocation is in progress and starts the



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  InitMINDelayBRIs timer.  The home agent maintains the mobile node BCE
  in this state until it receives a Binding Revocation Acknowledgement
  or retransmits the Binding Revocation Indication message as described
  in Section 6.3.

  In a race condition case, the home agent may receive a Binding Update
  from the mobile node while the mobile node's BCE has the revocation
  in progress flag set, the home agent SHOULD handle this case based on
  the reason for sending the Binding Revocation Indication message and
  its local policy.  In this case, if the home agent accepts the
  Binding Update, it needs to update the mobile node BCE accordingly,
  e.g., removing the revocation in progress flag.

  When the home agent needs to revoke one or more of a mobile node
  bindings that were created using multiple care-of address
  registrations as in [RFC5648], the home agent MUST include all the
  related BID mobility options that identify these bindings in the
  Binding Revocation Indication message.  In the case when the home
  agent needs to revoke all of the mobile node bindings, the home agent
  SHOULD NOT include any of the BID mobility options.

  When the home agent receives a packet carrying a valid Binding
  Revocation Acknowledgement message, the home agent follows
  Section 6.2 in processing this message.

8.  Local Mobility Anchor Operation

8.1.  Sending Binding Revocation Indication

  To terminate a mobile node PMIPv6 registration and its current
  binding with the local mobility anchor, the local mobility anchor
  sends a packet to the mobile access gateway containing a Binding
  Revocation Indication message following the procedure in Section 6.1
  and the following rules:

  o  The Proxy Binding (P) bit MUST be set to indicate that the binding
     being revoked is a PMIPv6 binding.

  o  The Revocation Trigger field MUST be set to indicate to the mobile
     access gateway the reason for removing the specified mobile node
     PMIPv6 binding at the local mobility anchor.  The Revocation
     Trigger may be used by the mobile access gateway to learn the
     mobile node's latest movement.

  o  The packet MUST contain the Mobile Node Identifier (MN-ID) option,
     which contains the mobile node's Network Access Identifier (NAI)
     that was used in the Proxy Binding Update during the mobile node
     registration.



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  o  If the Mobile Node Identifier (MN-ID) is registered in more than
     one of the mobile node's BCEs and the local mobility anchor does
     NOT need to revoke all of the mobile node's bindings, the Binding
     Revocation Indication message MUST contain another identifier to
     uniquely identify the mobile node binding(s) that is being
     revoked, e.g., at least one Home Network Prefix option that
     contains the mobile node's registered Home Network Prefix (HNP)
     for the binding being revoked.

  o  In the case of revoking all Per-Peer bindings, the local mobility
     anchor MUST set the Global (G) bit and the Revocation Trigger MUST
     contain the value "Per-Peer Policy" to request the mobile access
     gateway to remove all Per-Peer bindings that are registered with
     the local mobility anchor and this mobile access gateway.

  o  The proxy care-of address for the binding MUST be used as the
     destination address in the packet's IPv6 header.  However, in the
     case when IPsec is used to protect the Proxy MIPv6 signaling as
     specified in [RFC5213], the destination address MUST be set to the
     mag_address that is being used for keying the IPsec SA.  If the
     mag_address is different than the mobile node proxy care-of
     address, the Alternate Care-of Address option MUST be included and
     MUST contain the mobile node proxy care-of address.

  The local mobility anchor MAY delete the mobile node(s) IP tunnel
  immediately after sending the initial Binding Revocation Indication
  and before receiving the Binding Revocation Acknowledgement message.

  When the local mobility anchor sends a Binding Revocation Indication
  to the mobile access gateway to remove a specific binding, the local
  mobility anchor sets a flag in the mobile node proxy BCE to indicate
  that revocation is in progress and starts the InitMINDelayBRIs timer.
  The local mobility anchor SHOULD maintain the mobile node proxy BCE
  in this state until it receives a Binding Revocation Acknowledgement
  or the BRIMaxRetransmitNumber is reached.  In the case when the local
  mobility anchor sets the Revocation Trigger field to a value that
  indicates inter-MAG handover, the local mobility anchor MAY switch
  the mobile node IP tunnel to the target mobile access gateway before
  sending the Binding Revocation Indication to the source mobile access
  gateway.

  In a race condition case, the local mobility anchor may receive a
  Proxy Binding Update from the mobile access gateway while the mobile
  node's proxy BCE has the revocation in progress flag set.  The local
  mobility anchor should handle this case based on the reason for
  sending the Binding Revocation Indication message and its local





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  policy.  In this case, if the local mobility anchor accepts the Proxy
  Binding Update, it needs to update the mobile node proxy BCE
  accordingly, e.g., removing the revocation in progress flag.

  When the local mobility anchor needs to revoke all the mobile node
  proxy BCEs that are registered with the local mobility anchor and the
  mobile access gateway peer, it MUST set the Global (G) bit and set
  the value of the Revocation Trigger field to "Per-Peer Policy".  In
  this case, the local mobility anchor MUST NOT include any mobility
  options in this Binding Revocation Indication message.

  When the local mobility anchor needs to revoke all mobile nodes proxy
  BCEs that belong to a specific realm and are registered with the
  local mobility anchor and the mobile access gateway peer, the local
  mobility anchor MUST set the Global (G) bit and set the value of the
  Revocation Trigger field to "Revoking Mobility Node Local Policy".
  In this case, the local mobility anchor MUST include a mobility
  option in the Binding Revocation Indication that is shared among all
  the impacted mobile nodes BCEs, e.g., the mobile node identifier
  option, MN-ID option, with a subtype value of 1.  In this case, the
  NAI value in the MN-ID MUST follow the format where the content after
  the "@" character defines the realm that is shared amongst all of the
  impacted mobile nodes proxy BCEs.  As an example: @example.com
  identifies all mobile nodes whose MN-ID value contains "example.com"
  as the realm, e.g., "[email protected]", "[email protected]",
  and "[email protected]", but not
  "[email protected]".

  When the local mobility anchor needs to revoke a subgroup of the
  mobile nodes proxy BCEs that belong to a specific realm and are
  registered with the local mobility anchor and the mobile access
  gateway, the local mobility anchor MUST set the Global (G) bit and
  set the value of the Revocation Trigger field to "Revoking Mobility
  Node Local Policy".  In this case, the local mobility anchor MUST
  include an additional mobility option to the mobile node identifier
  option (MN-ID) option, with a subtype value of 1.  In other words,
  the impacted mobile node BCEs are those that have an MN-ID with a
  realm as specified above and, e.g., are assigned the same proxy
  care-of address as the one included in the Alternate Care-of Address
  mobility option.

  When the mobile node is registered with multiple Home Network
  Prefixes for the same proxy care-of address, the local mobility
  anchor SHOULD include an HNP option for each registered HNP in the
  Binding Revocation Indication.  Alternatively, it MAY include only
  the mobile node identifier (MN-ID) option with the mobile node NAI
  included to indicate to the mobile access gateway to remove all
  bindings of the specified mobile node NAI in the MN-ID option.



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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


  According to the Proxy Mobile IPv6 specification [RFC5213], if the
  local mobility anchor receives a Proxy Binding Update message from a
  new mobile access gateway for extending the binding lifetime of the
  only BCE of this mobile node with the Handoff Indicator value set to
  "Handoff state unknown (4)", the local mobility anchor waits a period
  of MaxDelayBeforeNewBCEAssign to receive a de-registration message
  from the previous mobile access gateway before updating the mobile
  node's BCE with the new point of attachment.  If a de-registration
  message is not received, the local mobility anchor considers the
  received Proxy Binding Update message as a request for a new BCE and
  if processed successfully, the local mobility anchor assigns a
  different HNP for the new BCE.

  This document updates the local mobility anchor's behavior in this
  case.  If the local mobility anchor supports the binding revocation
  mechanism as described in this document, it SHOULD proactively send a
  Binding Revocation Indication message to the previous mobile access
  gateway instead of waiting for a de-registration from the previous
  mobile access gateway.  In the Binding Revocation Indication message,
  the Revocation Trigger MUST be set to "Inter-MAG Handover - Unknown".

  If the local mobility anchor sent a Binding Revocation Indication
  message with the Revocation Trigger field set to "Inter-MAG Handover
  - Unknown" and while waiting for a response, Binding Revocation
  Acknowledgement, the following are possible conditions that the local
  mobility anchor MUST handle as specified below:

  o  If the local mobility anchor receives a successful Binding
     Revocation Acknowledgement message or a de-registration message
     from the previous mobile access gateway, the local mobility anchor
     MUST update the mobile node BCE as if it received a de-
     registration message as described in [RFC5213].

  o  If the local mobility anchor receives a Binding Revocation
     Acknowledgement message with the Status field set to "Revocation
     Failed - MN is Attached", the local mobility anchor SHOULD update
     the mobile node BCE as if it did NOT receive a de-registration
     before the MaxDelayBeforeNewBCEAssign timer expired by creating a
     new BCE as described in [RFC5213].

  o  If the local mobility anchor did not receive a Binding Revocation
     Acknowledgement message or a de-registration Proxy Binding Update
     from the previous mobile access gateway after it exhausted all of
     the Binding Revocation Indication message retransmissions as
     described in Section 6.3, the local mobility anchor SHOULD update
     the mobile node's BCE as if it did NOT receive a de-registration
     before the MaxDelayBeforeNewBCEAssign timer expired by creating a
     new BCE as described in [RFC5213].  Note that the local mobility



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     anchor SHOULD use the recommended number of retransmissions for
     the Binding Revocation Indication message as described in
     Section 11 to avoid delaying the creation of a new Binding Cache
     entry for too long, if the mobile node is actually attaching to
     the new MAG with a different interface.

  When the mobile node is registered with an IPv4 proxy home address in
  addition to the Home Network Prefix where both of the IPv4 proxy HoA
  (pHoA) and HNP are bound to the same proxy CoA (pCoA), the local
  mobility anchor MAY revoke the mobile node IPv4 proxy HoA binding to
  the current mobile node proxy CoA while maintaining the mobile node
  binding of the HNP to its current pCoA as part of the mobile node
  BCE.  In this case, if the local mobility anchor decides to revoke
  the mobile node IPv4 proxy HoA only, it MUST send a Binding
  Revocation Indication message following the procedure in Section 6.1
  and the following rules:

  o  The IPv4 HoA Binding Only (V) bit MUST be set in the BRI to
     indicate that only the IPv4 home address binding is being revoked.

  o  The IPv4 Home Address Request option MUST be included with the
     mobile node's registered proxy home IPv4 address that is being
     released in addition to the MN-ID option.

  o  The mobile node Home Network Prefix option MUST NOT be included.

  o  The Revocation Trigger field MUST be set to an appropriate value,
     e.g., "User Initiated Session(s) Termination".

8.2.  Receiving Binding Revocation Indication

  When the local mobility anchor receives a packet carrying a Binding
  Revocation Indication that was successfully processed as in
  Section 6.2, the local mobility anchor processes the message as
  follows:

  o  If the (P) bit is set, the local mobility anchor MUST validate
     that all impacted bindings have the proxy binding flag set.

  o  If the Global (G) bit is set and the Revocation Trigger field
     value is "Per-Peer Policy", the LMA MUST validate that the Proxy
     (P) bit is set and the MN-ID option is present with the mobile
     access gateway identity included.  In addition, the local mobility
     anchor MUST verify that the identified mobile access gateway as
     per the value in the MN-ID option is authorized to use the global
     revocation with revocation trigger value "Per-Peer Policy", see
     Section 13.  If the local mobility anchor processes the Global




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     Binding Revocation Indication message successfully, it MUST accept
     the Binding Revocation Indication message using the status code
     "success".

  o  If the mobile access gateway is not authorized to use the Per-Peer
     Global revocation feature or the received Binding Revocation
     Indication message has the Global (G) bit set and the Revocation
     Trigger field is set to "Per-Peer Policy", but the MN-ID option is
     not included, the local mobility anchor MUST reject the Binding
     Revocation Indication message using status code "Global Revocation
     NOT Authorized".

  o  If the Global (G) bit is set and the Revocation Trigger value is
     "Per-Peer Policy", and only the mobile node identifier (MN-ID)
     option is included, the local mobility anchor MUST revoke all
     mobile node bindings for which the proxy CoA is the one used as
     the source of the IPv6 packet that carried the Binding Revocation
     Indication.  However, if the Alternate Care-of Address option is
     included in addition to the mobile node identifier option, the
     local mobility anchor MUST revoke all mobile node bindings whose
     proxy care-of address matches the care-of address in the Alternate
     Care-of Address option.  After the local mobility anchor
     successfully processes the Binding Revocation Indication message
     and identifies all impacted mobile nodes bindings, it MUST accept
     the Binding Revocation Indication message using the status code
     "success".

  o  If the local mobility anchor accepted the Binding Revocation
     Indication message but one or more of the bindings identified in
     the received Binding Revocation Indication message has already
     been released, the local mobility anchor MUST accept the message
     and it MAY set the Status field to "partial success" and include
     the mobile node identifier (MN-ID) or the Home Network Prefix
     option to identify the binding(s) that failed the revocation
     procedure.

  o  If the Global (G) bit is not set, the local mobility anchor uses
     the included mobility options to identify the impacted mobile node
     binding as follows:

     1.  If only the mobile node identifier (MN-ID) option is included,
         the local mobility anchor MUST accept the message and revoke
         all bindings for this mobile node that use the specified
         mobile node NAI including the IPv4 Home Address binding(s) if
         present.






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     2.  If the mobile node identifier (MN-ID) and one Home Network
         Prefix option are included, the local mobility anchor MUST
         accept the message and only remove the specified mobile node
         proxy binding.

     3.  If the mobile node identifier (MN-ID) option and more than one
         Home Network Prefix options are included, the local mobility
         anchor MUST accept the message and remove all bindings that
         are referenced by these Home Network Prefixes for the
         specified mobile node NAI.

     4.  If the IPv4 HoA binding Only (V) bit is set and the mobile
         node identifier (MN-ID) option and the IPv4 Home Address
         Request option are included, the local mobility anchor MUST
         accept the message and remove only the IPv4 HoA address
         binding to the mobile node current proxy care-of address.

  The Revocation Trigger field value in the received Binding Revocation
  Indication could be used by the local mobility anchor to log an event
  or update some local parameters that track the state of the peer
  mobile access gateway.

  After the local mobility anchor accepts or rejects a Binding
  Revocation Indication message, the local mobility anchor MUST follow
  Sections 6.1 and 6.1.2 to send a Binding Revocation Acknowledgement
  message to the mobile access gateway.

9.  Mobile Access Gateway Operation

9.1.  Receiving Binding Revocation Indication

  When the mobile access gateway receives a packet carrying a Binding
  Revocation Indication that was successfully processed as in
  Section 6.2, the mobile access gateway processes the message as
  follows:

  o  If the Global (G) bit is set and the Revocation Trigger field
     value is "Per-Peer Policy", the mobile access gateway MUST
     validate that the Proxy (P) bit is set and no mobility options are
     included in the message.  If the mobile access gateway processes
     the Global Binding Revocation Indication message successfully, it
     MUST accept the Binding Revocation Indication message using the
     status code "success".

  o  If the Global (G) bit is set and the Revocation Trigger field
     value is "Revoking Mobility Node Local Policy", the mobile access
     gateway MUST validate that the Proxy (P) bit is set and at least
     the MN-ID option with the subtype value of 1 is included in the



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     Binding Revocation Indication and it is formatted as described is
     Section 8.1.  If the mobile access gateway processes this Global
     Binding Revocation Indication message successfully, it MUST accept
     the message using the status code "success".

  o  If the Global (G) bit is set and the Revocation Trigger field
     value is "Revoking Mobility Node Local Policy", and no mobility
     options are included in the Binding Revocation Indication message
     or the mobile access gateway is not able to identify the impacted
     mobile nodes bindings based on the included mobility options, the
     mobile access gateway MUST treat this as an error scenario.  In
     this case, the mobile access gateway MUST reject the Binding
     Revocation Indication message using status code "Revoked Mobile
     Nodes Identity Required".

  o  If the Revocation Trigger field value in the received Binding
     Revocation Indication message indicates inter-MAG handover, e.g.,
     Inter-MAG Handover - Unknown, the mobile access gateway uses the
     mobility option(s) included in the Binding Revocation Indication
     message to identify the mobile node binding.  The mobile access
     gateway SHOULD ensure that the mobile node is no longer attached
     to the mobile access gateway before accepting the BRI message
     using status code "success".  However, if the mobile access
     gateway verified that the mobile node is still directly attached,
     the mobile access gateway MUST reject the BRI using status code
     "Revocation failed - MN is Attached".

  o  If the IPv4 HoA Binding Only (V) bit is set, the mobile access
     gateway uses the MN-ID option to identify the mobile node binding
     entry in the Binding Update List (BUL).  The mobile access gateway
     MUST verify that the IPv4 address included in the IPv4 Home
     Address Request option in the received Binding Revocation
     Indication is the same as the IPv4 proxy HoA that is assigned to
     the mobile node.  After the mobile access gateway successfully
     validates the received IPv4 home address as the mobile node IPv4
     HoA, it MUST consider this as an indication to ONLY release the
     mobile node IPv4 proxy HoA binding to the mobile node current
     proxy CoA.  Consequently, it MUST continue to maintain the mobile
     node IPv6 proxy HoA or HNP binding to the current mobile node
     proxy CoA as part of the mobile node binding in the BUL entry and
     release all resources associated with the MN IPv4 proxy HoA
     binding to the MN pCoA.  If the mobile access gateway processed
     the BRI successfully, the mobile access gateway MUST accept the
     BRI using status code "success".  On the other hand, if the mobile
     access gateway is able to identify the mobile node binding using
     the MN-ID but failed to identify the received IPv4 proxy HoA, the
     mobile access gateway MUST reject the BRI using status code
     "Binding Does NOT Exist".



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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


  o  If the mobile access gateway accepts the Binding Revocation
     Indication message but one or more of the bindings identified in
     the received Binding Revocation Indication message has already
     been released before processing the Binding Revocation Indication,
     the mobile access gateway MUST accept the Binding Revocation
     Indication message.  In this case, the mobile access gateway MAY
     set the Status field to "partial success" and include the mobile
     node identifier (MN-ID) or the Home Network Prefix option to
     identify the binding(s) that failed to be removed as part of the
     revocation procedure.

  The Revocation Trigger field value in the received Binding Revocation
  Indication could be used by the mobile access gateway to define what
  actions the mobile access gateway could do to inform the mobile node
  that its IP connectivity to the current HNP has been terminated,
  e.g., if the Revocation Trigger field is set to "Administrative
  Reason", the mobile access gateway may terminate the IPv6 or IPv4
  mobility session on the access link and notify the mobile node.  The
  specific details and considerations on how the mobile access gateway
  terminates IPv6 or IPv4 mobility session on the access link and
  notifies the mobile node can be found in [RFC5213] and [RFC5844].

  After the mobile access gateway accepts or rejects a Binding
  Revocation Indication message, the mobile access gateway MUST follow
  Sections 6.1 and 6.1.2 to send a Binding Revocation Acknowledgement
  message to the local mobility anchor.

9.2.  Sending Binding Revocation Indication

  The mobile access gateway could send a Binding Revocation Indication
  message to indicate the termination of multiple mobile node bindings,
  e.g., when using the global revocation with the Global (G) bit set.
  In this case, when an event occurs that requires the mobile access
  gateway to inform the local mobility anchor peer to terminate all
  mobile node bindings that are registered at the local mobility anchor
  and the mobile access gateway, the mobile access gateway sends a
  Binding Revocation Indication message following the procedure in
  Section 6.1 and the following:

  o  The Proxy Binding (P) bit MUST be set to indicate that the
     binding(s) being revoked is a PMIPv6 binding.

  o  The Global (G) bit MUST be set and the Revocation Trigger MUST
     contain a value of "Per-Peer Policy" in the Binding Revocation
     Indication to request the local mobility anchor to remove all Per-
     Peer bindings that are registered with the local mobility anchor
     and the mobile access gateway.  In this case, the MN-ID option
     MUST be included in the Binding Revocation Indication and contain



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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


     the mobile access gateway identity.  In addition, the mobile
     access gateway MAY include the Alternate Care-of Address option.
     If included, the Alternate Care-of Address option MUST contain the
     proxy care-of address the bindings that are being impacted by this
     Binding Revocation Indication message.

  o  The mobile access gateway address MAY be used as the source
     address in the packet's IPv6 header.

  As described in Section 6.3, the mobile access gateway SHOULD
  retransmit the Binding Revocation Indication to the local mobility
  anchor until it receives a matching Binding Revocation
  Acknowledgement or the BRIMaxRetransmitNumber is reached.  The mobile
  access gateway MAY delete the mobile node IP tunnels immediately
  after sending the Binding Revocation Indication and before receiving
  a Binding Revocation Acknowledgement message from the LMA.

  In response to a Binding Revocation Indication message, if the mobile
  access gateway receives a packet carrying a Binding Revocation
  Acknowledgement that was successfully processed as in Section 6.2 and
  the Status field indicates "Global Revocation NOT Authorized", the
  mobile access gateway is not authorized to participate in a Per-Peer
  Global Revocation.  The mobile access gateway SHOULD NOT retry
  sending a Binding Revocation Indication with the Global (G) bit set
  and the Revocation Trigger field value set to "Per-Peer Policy" to
  the same local mobility agent.  The mobile access gateway should
  raise an alarm or log an event to indicate this rejection.

10.  Mobile Node Operation

  Upon receiving a packet carrying a Binding Revocation Indication, the
  mobile node MUST validate the packet according to Section 6.2 and the
  following tests:

  o  The mobile node MUST verify that the IP address in the Type 2
     routing header is its Home Address and that its Binding Update
     List contains an entry for that Home Address.  If one of the tests
     fails, the mobile node SHOULD silently discard the received
     Binding Revocation Indication message.

  o  If mobile node Binding Update List contains an entry for the IP
     address in the Type 2 routing header of the received Binding
     Revocation Indication packet, the mobile node MUST accept the BRI
     message using status code "success".

  o  If the IPv4 HoA Binding Only (V) bit is set in the received BRI
     message, the mobile node MUST verify that there is an IPv4 Home
     Address option in the received Binding Revocation Indication and



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     the IPv4 address included in the IPv4 Home Address option is the
     same as its IPv4 HoA that is assigned to the mobile node.  If this
     verification is successful, the mobile node MUST consider this
     Binding Revocation Indication as an indication to ONLY release the
     mobile node IPv4 HoA binding to its current care-of address.
     Consequently, the mobile node MUST continue to maintain its IPv6
     HoA binding to the current CoA as part of the mobile node binding
     in the BUL entry and release all resources associated with the MN
     IPv4 HoA binding.  In this case, the mobile node MUST accept the
     Binding Revocation Indication message using status code "success".
     On the other hand, if the IPv4 Home Address Option was NOT
     included in the received BRI with the (V) bit is set, the MN MUST
     reject the BRI message with status code "IPv4 Home Address Option
     Required".  Additionally, if the IPv4 HoA received in the IPv4
     Home Address Option is NOT the one assigned to the mobile node,
     the mobile node SHOULD reject the Binding Revocation Indication
     with status code "Binding Does NOT Exist".

  o  The mobile node MUST verify that the (P) bit in the Binding
     Revocation Indication is NOT set.  If the (P) bit is set, the
     mobile node MUST reject the Binding Revocation Indication using
     status code "Proxy Binding Revocation NOT Supported".

  o  If the mobile node has registered multiple care-of addresses with
     its home agent, the mobile node MUST verify which binding is being
     revoked by examining the content of the Binding Revocation
     Indication message.  If the mobile node received a Binding
     Revocation Indication with one or more BID options and its home
     address is included in the Type 2 routing header, the mobile node
     MUST consider all of the care-of addresses bindings, identified in
     the BID options, with this home address as being revoked.  In this
     case, if the BRI validation is successful, the mobile node MUST
     accept the Binding Revocation Indication message with status code
     "success".

  o  If the mobile node has multiple care-of address bindings with its
     home agent and received a Binding Revocation Indication, without
     any BID option included and its home address was included in the
     Type 2 routing header, the mobile node MUST consider all of its
     registered care-of address bindings with this home address as
     being revoked.  If the mobile node validates the BRI successfully,
     the mobile node MUST accept the Binding Revocation Indication
     message with status code "success".

  If the mobile node accepts or rejects the Binding Revocation
  Indication message, the mobile node MUST follow Sections 6.1 and
  6.1.2 to send a Binding Revocation Acknowledgement message to the
  home agent.  Note that anytime the MN does not send a Binding



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  Revocation Acknowledgement to a BRI, the initiator is likely to
  retransmit the BRI at least one time.  This causes additional load on
  the initiator who sends the retransmissions, as well as on the MN
  that will receive and process them.

  The Revocation Trigger field value in the received Binding Revocation
  Indication could be used by the mobile node to define what action the
  mobile node could do to be able to register again and receive its IP
  mobility service, e.g., contacting its home operator.

11.  Protocol Configuration Variables

  Any mobility entity that is allowed to invoke the binding revocation
  procedure by sending a Binding Revocation Indication message SHOULD
  allow the following variables to be configured.

  BRI Maximum Number of Retries (BRIMaxRetriesNumber)

     This variable specifies the maximum Number of times a mobility
     entity can retransmit a Binding Revocation Indication message
     before receiving a Binding Revocation Acknowledgement message.
     The default value for this parameter is 1.

  Initial Minimum Delay Between BRI messages (InitMINDelayBRIs)

     This variable specifies the initial delay timeout in seconds
     before the revoking mobility entity retransmits a BRI message.
     The default is 1 second but is not to be configured to less than
     0.5 seconds.

  Maximum BRA TIMEOUT (MAX_BRACK_TIMEOUT)

     This variable specifies the maximum delay timeout in seconds
     before the revoking mobility entity retransmits a BRI message.
     The default is 2 seconds.

12.  IANA Considerations

  This specification defines a new Binding Revocation Message using a
  new Mobility Header Type 16, as described in Section 5.  The new
  Mobility Header type value needs to be assigned from the same
  numbering space as allocated for the other Mobility Header types
  registry.

  This document also creates a new registry "Binding Revocation Type"
  that indicates the type of the binding revocation message.  The
  current binding revocation message types are described in Sections
  5.1 and 5.2, and are the following:



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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


      0  Reserved
      1  Binding Revocation Indication
      2  Binding Revocation Acknowledgement
      All other values are unassigned

  Future values of the Binding Revocation Type can be allocated using
  Standards Action or IESG Approval [RFC5226].

  In addition, this document also creates a second new registry for the
  Revocation Trigger that indicates the reason behind sending the
  Binding Revocation Indication message.  The current Revocation
  Trigger values are described in Section 5.1, and are the following:

  Per-MN Revocation Trigger Values:
      0  Unspecified
      1  Administrative Reason
      2  Inter-MAG Handover - same Access Type
      3  Inter-MAG Handover - different Access Type
      4  Inter-MAG Handover - Unknown
      5  User-Initiated Session(s) Termination
      6  Access Network Session(s) Termination
      7  Possible Out-of-Sync BCE State

  Global Revocation Trigger Values:
      128  Per-Peer Policy
      129  Revoking Mobility Node Local Policy

  Reserved Revocation Trigger Values:
      250-255 Reserved For Testing Purposes only
      All other values are Unassigned

  Future values of the Revocation Trigger can be allocated using
  Standards Action or IESG Approval [RFC5226].

  Furthermore, this document creates a third new registry "Binding
  Revocation Acknowledgement Status Codes".  The current values are
  described in Section 5.2, and are the following:

        0  success
        1  partial success
      128  Binding Does NOT Exist
      129  IPv4 Home Address Option Required
      130  Global Revocation NOT Authorized
      131  Revoked Mobile Nodes Identity Required
      132  Revocation Failed - MN is Attached
      133  Revocation Trigger NOT Supported
      134  Revocation Function NOT Supported
      135  Proxy Binding Revocation NOT Supported



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  Future values of the Status field can be allocated using Standards
  Action or IESG Approval [RFC5226].

  All fields labeled "Reserved" are only to be assigned through
  Standards Action or IESG Approval.

13.  Security Considerations

  This specification allows the mobility node that initiates the
  binding revocation procedure to revoke a mobility session(s) that is
  currently registered with it.  It is NOT allowed for any mobility
  node to revoke a mobile node mobility session that is not registered
  with this mobility node.

  The binding revocation protocol described in this specification uses
  the same security association between the mobile node and the home
  agent or the mobile access gateway and the local mobility anchor that
  is being used to exchange the MIPv6 or PMIPv6 Binding Update and
  Binding Acknowledgement signaling.  If IPsec is used, the traffic
  selectors associated with the Security Policy Database (SPD) entry
  protecting the Binding Update and Binding Acknowledgement MUST be
  extended to include Binding Revocation Message MH type 16.  Extending
  the traffic selectors of the SPD entry in order to reuse the SA
  protecting the Binding Update and Binding Acknowledgement (instead of
  creating new ones) ensures that those SAs will be up and running when
  the revoking entity needs to send a binding revocation signaling
  message.

  On the other hand, if IPsec is not used as the underlying security
  mechanism to protect the Mobile IPv6 and its extensions binding
  registration signaling, the used underlying security mechanism MUST
  provide protection against all identified security threats as
  described under "Security Considerations" in [RFC3775] and [RFC5213].

  Since some mobility entities, e.g., local mobility anchor and mobile
  access gateway, are allowed to send and receive Binding Revocation
  Indications and Binding Revocation Acknowledgements for different
  cases, when IPsec is used to secure signaling between the local
  mobility anchor and mobile access gateway, it prevents any of them
  from processing a Binding Revocation Message that was not constructed
  by an authorized party.

  The Proxy Mobile IPv6 [RFC5213] requires the local mobility anchor to
  restrict the creation and manipulation of proxy bindings to
  specifically authorized mobile access gateways.  Therefore, the
  mobile access gateway that is authorized to create or manipulate the
  mobile node proxy BCE is also authorized to revoke such mobile node
  registration by sending a de-registration with lifetime of zero.



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  However, since bulk termination using Binding Revocation Indication
  with the Global (G) bit set and the Revocation Trigger field set to
  "Per-Peer Policy" impacts all mobility sessions that are registered
  with the mobile access gateway and its local mobility anchor peer,
  the local mobility anchor MUST be locally configurable to authorize
  such specific functionality.  Additional mechanisms, such as a policy
  store or Authentication, Authorization, and Accounting (AAA) may be
  employed, but these are outside the scope of this specification.

14.  Acknowledgements

  The authors would like to thank Ryuji Wakikawa, Bruno Mongazon-
  Cazavet, Domagoj Premec, Arnaud Ebalard, Patrick Stupar, Vijay
  Devarapalli, and Joel Hortelius for their review and comments of this
  document and all colleagues who have supported the advancement of
  this effort.

  Also, we would like to thank Jari Arkko, Ben Campbell, Pasi Eronen,
  Ralph Droms, Alexey Melnikov, Tim Polk, Adrian Farrel, and Robert
  Sparks for their reviews of this document as part of the IESG review
  process.

15.  References

15.1.  Normative References

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

  [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
             IANA Considerations Section in RFCs", BCP 26, RFC 5226,
             May 2008.

  [RFC3775]  Johnson, D., Perkins, C., and J. Arkko, "Mobility Support
             in IPv6", RFC 3775, June 2004.

  [RFC4283]  Patel, A., Leung, K., Khalil, M., Akhtar, H., and K.
             Chowdhury, "Mobile Node Identifier Option for Mobile IPv6
             (MIPv6)", RFC 4283, November 2005.

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

  [RFC5844]  Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
             Mobile IPv6", RFC 5844, May 2010.






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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


  [RFC5648]  Wakikawa, R., Devarapalli, V., Tsirtsis, G., Ernst, T.,
             and K. Nagami, "Multiple Care-of Addresses Registration",
             RFC 5648, October 2009.

  [RFC5555]  Soliman, H., "Mobile IPv6 Support for Dual Stack Hosts and
             Routers", RFC 5555, June 2009.

15.2.  Informative References

  [RFC3344]  Perkins, C., "IP Mobility Support for IPv4", RFC 3344,
             August 2002.

  [RFC3543]  Glass, S. and M. Chandra, "Registration Revocation in
             Mobile IPv4", RFC 3543, August 2003.





































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RFC 5846          Binding Revocation for IPv6 Mobility         June 2010


Authors' Addresses

  Ahmad Muhanna
  Ericsson, Inc.
  2201 Lakeside Blvd.
  Richardson, TX  75082
  USA

  EMail: [email protected]


  Mohamed Khalil
  Ericsson, Inc.
  6300 Legacy Dr.
  Plano, TX  75024
  USA

  EMail: [email protected]


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

  EMail: [email protected]


  Kuntal Chowdhury
  Cisco
  30 International Place
  Tewksbury, MA  01876
  USA

  EMail: [email protected]


  Parviz Yegani
  Juniper Networks
  1194 North Mathilda Avenue
  Sunnyvale, CA  94089
  USA

  EMail: [email protected]






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