





Internet Engineering Task Force (IETF)                  F. Abinader, Ed.
Request for Comments: 6602                 Instituto Nokia de Tecnologia
Category: Standards Track                             S. Gundavelli, Ed.
ISSN: 2070-1721                                                 K. Leung
                                                                   Cisco
                                                             S. Krishnan
                                                                Ericsson
                                                               D. Premec
                                                            Unaffiliated
                                                                May 2012


           Bulk Binding Update Support for Proxy Mobile IPv6

Abstract

   For extending the lifetime of a mobility session, the Proxy Mobile
   IPv6 specification requires the mobile access gateway to send a Proxy
   Binding Update message to the local mobility anchor on a per-session
   basis.  In the absence of signaling semantics for performing
   operations with group-specific scope, this results in a significant
   amount of signaling traffic on a periodic basis between a given
   mobile access gateway and a local mobility anchor.  This document
   defines optimizations to the binding update and revocation operations
   in Proxy Mobile IPv6 for performing operations with group-specific
   scope with the use of a group identifier.

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/rfc6602.

Copyright Notice

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






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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1. Introduction ....................................................3
   2. Conventions and Terminology .....................................4
      2.1. Conventions ................................................4
      2.2. Terminology ................................................4
   3. Bulk Binding Update Overview ....................................4
      3.1. Motivation .................................................4
      3.2. General Operation ..........................................5
   4. Message Formats .................................................8
      4.1. Extensions to Proxy Binding Update Message .................9
      4.2. Extensions to Proxy Binding Acknowledgement Message .......10
      4.3. Mobile Node Group Identifier Option .......................10
      4.4. Status Codes ..............................................11
   5. Protocol Considerations ........................................12
      5.1. MAG Considerations ........................................12
           5.1.1. Extensions to Binding Update List Entry
                  Data Structure .....................................12
           5.1.2. Requesting Bulk Binding Update Support for
                  a Mobility Session .................................12
           5.1.3. Supporting Bulk Binding Updates ....................14
      5.2. LMA Considerations ........................................15
           5.2.1. Extensions to Binding Cache Entry Data Structure ...15
           5.2.2. Enabling Bulk Binding Update Support for a
                  Mobility Session ...................................16
           5.2.3. Supporting Bulk Binding Updates ....................18
   6. Protocol Configuration Variables ...............................20
      6.1. Local Mobility Anchor - Configuration Variables ...........20
      6.2. Mobile Access Gateway - Configuration Variables ...........20
   7. IANA Considerations ............................................20
   8. Security Considerations ........................................21
   9. Acknowledgements ...............................................21
   10. References ....................................................22
      10.1. Normative References .....................................22
      10.2. Informative References ...................................22






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1.  Introduction

   The Proxy Mobile IPv6 base specification [RFC5213] requires the
   Mobile Node Identifier option to be present in the mobility signaling
   messages, such as in the Proxy Binding Update (PBU) and Proxy Binding
   Acknowledgement (PBA) messages.  It essentially limits the
   operational scope of the binding update operation to a single
   mobility session.  These signaling messages lack the capability to
   identify a group of mobility sessions, so the operations related to
   binding update and revocation can be performed on all the mobility
   sessions that are part of that group.

   There is a need to have semantics for associating a group identity to
   a mobility session, so the scope of the operations related to binding
   update and revocation can be extended to all the mobility sessions
   identified by the group identifier.  The group identifier therefore
   provides a considerably improved mechanism for protocol operations
   that would otherwise require multiple atomic transactions on a per-
   mobility-session basis.  Following are some of the use cases where
   the group identifier can be used.

   o  For extending the lifetime of a mobility session, the mobile
      access gateway (MAG) periodically sends a Proxy Binding Update
      message to the local mobility anchor (LMA) on a per-session basis.
      This process can be optimized by allowing the mobile access
      gateway to send a single Proxy Binding Update [RFC5213] message
      for a group of mobility sessions identified by a group identifier.
      Upon accepting the request, the local mobility anchor can update
      the lifetime of all the mobility sessions that are part of that
      group.

   o  On detecting the failure of a specific service card, a local
      mobility anchor, or a mobile access gateway service hosted on
      blade architecture system, can potentially request the peer to
      revoke all the sessions identified by a common group identifier
      that are hosted on that service card.  Potentially, a single
      Binding Revocation Indication [RFC5846] message carrying the group
      identifier can be used to revoke all the sessions hosted on that
      service card, which otherwise needs to be handled on a per-session
      basis.

   This document defines a new mobility option, the Mobile Node Group
   Identifier option, and the extensions to procedures related to
   binding update and binding revocation for performing binding
   operations with group-specific scope.






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2.  Conventions and Terminology

2.1.  Conventions

   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 RFC 2119 [RFC2119].

2.2.  Terminology

   All the mobility-related terms used in this document are to be
   interpreted as defined in the base Proxy Mobile IPv6 specifications
   [RFC5213] and [RFC5844].  Additionally, this document uses the
   following terms:

   Bulk Binding Update

      A binding update operation that has group-specific scope.  A
      binding operation is associated with a specific mobility session.
      However, a bulk binding update operation is associated with
      multiple mobility sessions.  This operation is not relevant for
      new mobility session creation.

   Bulk Binding Update Group

      A group of mobility sessions that are part of the same logical
      group and therefore share a common group identifier.  This group
      is the bulk binding update group.  This bulk binding update group
      is maintained by both the mobile access gateway and the local
      mobility anchor, and the grouping logic is local to that node.  A
      mobility session can therefore be identified by two bulk binding
      update group identifiers, one specific group created by the mobile
      access gateway and the other specific group created by the local
      mobility anchor.  The bulk binding update group identifiers are
      exchanged as part of the initial mobility session creation.  The
      mobility entities thereafter can perform operations related to
      binding update such as lifetime extension and revocation
      operations on an entire bulk binding update group identified by
      the group identifier.

3.  Bulk Binding Update Overview

3.1.  Motivation

   In a typical Proxy Mobile IPv6 domain, a local mobility anchor serves
   multiple mobile access gateways, and the capacity of that node with
   respect to the number of mobility sessions that it can host is quite
   high, typically in the order of a few millions.  As the number of



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   mobility sessions hosted by a local mobility anchor goes up, so does
   the amount of signaling traffic related to periodic binding update
   traffic.

   The currently specified approach of the binding update procedure for
   extending the lifetimes of multiple mobility sessions (where the
   mobile access gateway is required to send a unique binding update
   message for each mobility session even when there is no change to the
   session state) is inefficient or sub-optimal.  These periodic binding
   update messages consume a significant amount of network resources at
   both the peers, in terms of processing power and network bandwidth.
   There is an opportunity to optimize the signaling procedures by
   allowing the local mobility anchor and the mobile access gateway to
   perform bulk binding update operations.  This document specifies
   extensions to Proxy Mobile IPv6 signaling for performing binding
   update and revocation operations on a group of mobility sessions.
   These extensions do not take away the existing functionality of
   performing binding operations on a single mobility session.

3.2.  General Operation

   The bulk binding update mechanism specified in this document allows
   the mobile access gateway and the local mobility anchor to perform
   binding update and revocation operations on a group of mobility
   sessions.  As part of the initial signaling during mobility session
   establishment, the local mobility anchor and the mobile access
   gateway exchange the respective bulk binding update group identifiers
   for that mobility session.  Subsequently, both the peers can perform
   bulk operations on those groups by presenting the bulk binding update
   group identifier in the signaling messages.

   When sending a Proxy Binding Update message after detecting a new
   mobile node on its access link, a mobile access gateway can request
   the local mobility anchor to assign a bulk binding update group
   identifier for the mobile node's mobility session.  This is indicated
   by setting the (B) flag in the Proxy Binding Update to a value of
   (1).  The mobile access gateway will also assign a bulk binding
   update group identifier (or it may assign a default bulk binding
   update group - ALL-SESSIONS) and include that in the Mobile Node
   Group Identifier option.

   Upon accepting the request, the local mobility anchor will group the
   mobility session to a specific bulk binding update group (or it may
   assign it to the default bulk binding update group - ALL-SESSIONS)
   and return this bulk binding update group identifier in a Proxy
   Binding Acknowledgement message.  It will also set the (B) flag in





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   the Proxy Binding Acknowledgement message to a value of (1).  The
   bulk binding update group identifier is carried in the Mobile Node
   Group Identifier option, described in Section 4.3.

   Once the bulk binding update group identifiers are exchanged, the
   local mobility anchor and the mobile access gateway can perform
   binding operations on those entire groups, by including the bulk
   binding update group identifier in the signaling messages.  For
   example, the mobile access gateway can extend the lifetime of all the
   mobility sessions that are part of a group by sending a single Proxy
   Binding Update message with that bulk binding update group
   identifier.  Similarly, the local mobility anchor can revoke all the
   mobility sessions that are part of a group by including that group
   identifier in the Proxy Binding Revocation message.  When initiating
   bulk binding update operations on a group of mobility sessions, the
   group identifier that is carried in the Mobile Node Group Identifier
   option is always the identifier of the local group, and not the
   identifier of the group on the peer.

   Figure 1 explains the operational sequence of the bulk binding update
   and revocation operations on a group of mobile nodes (MN1, MN2, and
   MN3).





























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              MAG                         LMA
         (1)  |                            |
    MN1-------|           (2) PBU          |
              |--------------------------->|
              |                            * (3)
              |           (4) PBA          |
              |<---------------------------|
              * (5)                        |
         (6)  |                            |
    MN2-------|                            |
              * (7)........................|
         (8)  |                            |
    MN3-------|                            |
              * (9)........................|
              |                            |
              |           (10) PBU         |
              |--------------------------->|
              |                            * (11)
              |           (12) PBA         |
              |<---------------------------|
              * (13)
              |                            |
              |           (14) BRI         |
              |<---------------------------|
              |                            * (15)
              |           (16) BRA         |
              |--------------------------->|
              * (17)                       |
              |                            |

          Figure 1: Exchange of Group Identifier

   o  (1) to (2): The MAG detects the mobile node's (MN1) attachment to
      the access link.  The MAG groups the mobile node to a specific
      bulk binding update group, (M1).  The MAG notifies this group
      identifier to the LMA by including it in the Mobile Node Group
      Identifier option of the PBU message.

   o  (3): Upon accepting the PBU, the LMA creates a mobility session
      and groups the mobility session to a specific bulk binding update
      group, (L1).  The LMA updates the mobile node's Binding Cache
      entry to include the bulk binding update group identifier, (L1),
      and the bulk binding update group identifier presented by the MAG,
      (M1).  The LMA also notifies the MAG about the bulk binding update
      group identifier (L1), by including it in the PBA.






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   o  (4) to (5): Upon receiving the PBA, the MAG updates the Binding
      Update List entry for that mobility session to include the bulk
      binding update group identifiers (L1) and (M1).  At this point,
      both the LMA and MAG are aware of the mobile node's bulk binding
      update group identifiers assigned by the peers.

   o  (6) to (9): The above steps (1 through 5) are repeated here for
      MN2 and MN3; details are omitted.  At the end of step (9), the MAG
      completes the signaling with the LMA.  The MAG assigns the mobile
      nodes MN2 and MN3 to bulk binding update groups (M1) and (M2)
      respectively, while the LMA assigns them both to the same bulk
      binding update group, (L1).

   o  At this point, LMA has assigned MN1, MN2, and MN3 to the bulk
      binding update group (L1), while the MAG has assigned MN1 and MN2
      to group (M1) and MN3 to group (M2).  Both peers can now perform
      binding operations on a group of mobility sessions identified by
      the respective bulk binding update group identifier.

   o  (10) to (13): The MAG sends a Proxy Binding Update message for
      extending the lifetime of all the mobility sessions that are part
      of the bulk binding update group (M1).  It includes the bulk
      binding update group identifier (M1) in the PBU.  Upon accepting
      the PBU, the LMA extends the lifetime of both MN1 and MN2, which
      are part of the group (M1).

   o  (14) to (17): The LMA decides to revoke all the sessions that are
      part of bulk binding update group (L1).  The LMA sends a Binding
      Revocation Indication (BRI) message with the bulk binding update
      group identifier (L1).  Upon accepting the BRI message, the MAG
      revokes all the MN1, MN2, and MN3 mobility sessions, which are
      part of that bulk binding update group (L1), and sends a Binding
      Revocation Acknowledgement (BRA) [RFC5846] message.

4.  Message Formats

   This section identifies the extensions to Proxy Mobile IPv6 signaling
   messages that are required for supporting this specification.













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4.1.  Extensions to Proxy Binding Update Message

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
                                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                   |            Sequence #         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |A|H|L|K|M|R|P|F|T|B| Reserved  |            Lifetime           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   .                                                               .
   .                        Mobility options                       .
   .                                                               .
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

           Figure 2: Extensions to Proxy Binding Update Message

   A new flag, the Bulk-Binding-Update flag (B), is defined in the Proxy
   Binding Update message specified in [RFC5213].  The bit value of
   Bulk-Binding-Update flag (B) in the flags field of the message will
   be 0x0040.

   If the Bulk-Binding-Update flag (B) is set to a value of (1), it
   informs the local mobility anchor to enable bulk binding update
   support for the mobility session associated with this message.  If
   the (B) flag is set to a value of (0), the local mobility anchor MUST
   exclude the mobility session associated with this message from any
   bulk-binding-related operations and any binding update, or binding
   revocation operations with bulk-specific scope will not be relevant
   to that mobility session.

   This flag is relevant only for Proxy Mobile IPv6 and therefore MUST
   be set to the value of (0) when the (P) flag is set to a value of
   (0).

   All other fields in the Proxy Binding Update message and the mobility
   options that can be carried in the message conform to the appropriate
   specifications.












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4.2.  Extensions to Proxy Binding Acknowledgement Message

    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
                                   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                   |   Status      |K|R|P|T|B| Res.|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         Sequence #            |           Lifetime            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   .                                                               .
   .                        Mobility options                       .
   .                                                               .
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

       Figure 3: Extensions to Proxy Binding Acknowledgement Message

   A new flag, the Bulk-Binding-Update flag (B), is defined in the Proxy
   Binding Acknowledgement message specified in [RFC5213].  The bit
   value of Bulk-Binding-Update flag (B) in the flags field of the
   message is 0x08.

   If the Bulk-Binding-Update flag (B) is set to a value of (1), it
   serves as an indication to the mobile access gateway that the local
   mobility anchor has enabled bulk binding update support for the
   mobility session associated with this message.  The value of the flag
   MUST be set to the value of (0) if the value of the (B) flag in the
   Proxy Binding Update message that it received from the mobile access
   gateway was set to a value of (0).

   This flag is relevant only for Proxy Mobile IPv6 and therefore MUST
   be set to a value of (0) when the (P) flag is set to a value of (0).

   All other fields in the Proxy Binding Acknowledgement message and the
   mobility options that can be carried in the message conform to the
   appropriate specifications.

4.3.  Mobile Node Group Identifier Option

   A new option, the Mobile Node Group Identifier option, is defined for
   use in Proxy Mobile IPv6 signaling messages exchanged between a local
   mobility anchor and a mobile access gateway.  This option is used for
   carrying the mobile node's group identifier.  There can be multiple
   instances of this option in a given signaling message; however, each
   of the instances SHOULD have a different sub-type value.  This option
   is a generic option, and this specification uses only the sub-type
   value of (1).



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   The type value for this option is 50.

   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      Type     |   Length      |  Sub-type   |    Reserved     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  Mobile Node Group Identifier                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

               Figure 4: Mobile Node Group Identifier Option

   Type
      <50>

   Length
      This is an 8-bit unsigned integer indicating the length in octets
      of this option, excluding the type and length fields.  The value
      for this field MUST be set to a value of (6).

   Sub-type
      This 8-bit field identifies the specific mobile node's group type.
      This number space will be managed by the IANA.  The sub-type value
      of (1) is reserved for the Bulk Binding Update Group.

   Reserved
      This 8-bit field is unused for now.  The value MUST be initialized
      to (0) by the sender and MUST be ignored by the receiver.

   Mobile Node Group Identifier
      This 32-bit field contains the mobile node's group identifier.
      The value of (0) is reserved and SHOULD NOT be used.  The value of
      (1) ALL-SESSIONS is the default group of all mobility sessions
      established between a given local mobility anchor and a mobile
      access gateway.

4.4.  Status Codes

   This document defines the following new status code values for use in
   the Proxy Binding Acknowledgement message.  These values have been
   allocated from the same number space as defined in Section 6.1.8 of
   [RFC6275].

   INVALID_MOBILE_NODE_GROUP_IDENTIFIER: 175

      Invalid group identifier value in the request





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5.  Protocol Considerations

5.1.  MAG Considerations

   The following are the considerations relevant to the mobile access
   gateway when supporting this specification.

5.1.1.  Extensions to Binding Update List Entry Data Structure

   The conceptual Binding Update List entry data structure maintained by
   the mobile access gateway, described in Section 6.1 of [RFC5213], is
   extended to include the following REQUIRED additional fields:

   o  MAG-Bulk-Binding-Update-Group-Id
      This is the bulk binding update group identifier assigned by this
      mobile access gateway for this mobility session.  It is a 32-bit
      unsigned integer.  This identifier is not globally unique within a
      Proxy Mobile IPv6 domain; the same group identifier value may be
      used by other nodes.

   o  LMA-Bulk-Binding-Update-Group-Id
      This is the bulk binding update group identifier assigned by the
      local mobility anchor for this mobility session.  It is a 32-bit
      unsigned integer.  This identifier is received in the Mobile Node
      Group Identifier option of the Proxy Binding Acknowledgement
      message.  This identifier is not globally unique within a Proxy
      Mobile IPv6 domain; the same group identifier value may be used by
      other nodes.

5.1.2.  Requesting Bulk Binding Update Support for a Mobility Session

   The following are the considerations for the mobile access gateway
   for requesting bulk binding update support for a mobility session.

   o  When sending a Proxy Binding Update message to the local mobility
      anchor, the mobile access gateway can choose to request that the
      local mobility anchor enable bulk binding update support for the
      mobility session associated with that Proxy Binding Update
      request.  When making such request, the Bulk-Binding-Update flag
      (B) in the request MUST be set to a value of (1) and the Mobile
      Node Group Identifier option MUST be present.  The decision to
      request bulk binding update support for a mobile node is a matter
      of local policy at the mobile access gateway and is controlled by
      the configuration variable
      RequestBulkBindingUpdateSupportForMobilitySession.






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   o  The mobile access gateway MUST assign a bulk binding update group
      identifier for the mobility session.  Considerations on how the
      mobile access gateway assigns a group identifier to a mobility
      session is outside the scope of this document.  This group
      identifier can be unique to the service card on which the mobility
      session is hosted or based on other grouping considerations.  When
      no such group assignment is done, the mobile access gateway SHOULD
      assign the default group identifier value of (ALL-SESSIONS).  This
      assigned group identifier value MUST be present in the Mobile Node
      Group Identifier option, and the sub-type value in the option MUST
      be set to the value of (1) (Bulk Binding Update Group).

   o  If the received Proxy Binding Acknowledgement message has the
      status code value set to (0) (Proxy Binding Update accepted) and
      the Bulk-Binding-Update flag (B) set to a value of (0), in
      response to a Proxy Binding Update request with the Bulk-Binding-
      Update flag (B) set to a value of (1), it is an indication that
      the local mobility anchor has denied the request for enabling bulk
      binding update support for that mobility session and that the
      mobility session is not associated with any bulk binding update
      group.  The mobile access gateway SHOULD set the bulk binding
      update group identifier values LMA-Bulk-Binding-Update-Group-Id
      and MAG-Bulk-Binding-Update-Group-Id to (0) in the Binding Update
      List entry for that mobility session.  Furthermore, the mobility
      session should be excluded from any bulk binding update
      operations.

   o  If the received Proxy Binding Acknowledgement message has the
      status code value set to (0) (Proxy Binding Update accepted) and
      the Bulk-Binding-Update flag (B) in the reply is set to a value of
      (1), it is an indication that the local mobility anchor has
      accepted the request to allow bulk binding update support for that
      mobility session.  Furthermore, the Mobile Node Group Identifier
      option in the reply, with the sub-type value of (1) (Bulk Binding
      Update Group), contains the bulk binding update group identifier
      for that mobility session assigned by the local mobility anchor.
      The mobile access gateway MUST update the LMA-Bulk-Binding-Update-
      Group-Id and MAG-Bulk-Binding-Update-Group-Id parameters in the
      Binding Update List entry for that mobility session.  However, if
      the received Proxy Binding Acknowledgement message has the Bulk-
      Binding-Update flag (B) set to a value of (1), but the Mobile Node
      Group Identifier option is not present, the message MUST be
      considered malformed and ignored.

   o  If, at any point in time, the mobile access gateway chooses to
      request the local mobility anchor to disable bulk binding update
      support for a mobility session, it MUST send a Proxy Binding
      Update message with the (B) flag set to a value of (0), and the



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      Mobile Node Group Identifier option MUST NOT be present.  This
      message is sent as a normal binding update request for lifetime
      extension.  Requirements from Section 6.9.1 of [RFC5213] apply.
      Furthermore, the mobile access gateway MUST update the Binding
      Update List entry by setting the bulk binding update group
      identifier values LMA-Bulk-Binding-Update-Group-Id and MAG-Bulk-
      Binding-Update-Group-Id to (0), and the mobility session MUST be
      excluded from any bulk binding update operations.

5.1.3.  Supporting Bulk Binding Updates

   The following section identifies the considerations for a mobile
   access gateway performing binding update and revocation operations
   with group-specific scope.

   o  For extending the lifetime of all mobility sessions that share the
      same bulk binding update group identifier, the mobile access
      gateway can choose to send a bulk binding update request.  To make
      such a request, it can send a Proxy Binding Update message to the
      local mobility anchor, including the Mobile Node Group Identifier
      option with the sub-type value of (1) (Bulk Binding Update Group)
      and with the Bulk-Binding-Update flag (B) set to a value of (0).
      The identifier value in the option MUST be set to the bulk binding
      update group identifier of the group for which bulk binding update
      operation is being requested.  The message MUST NOT include any
      individual session identifiers such as the Mobile Node Identifier
      option [RFC4283], the Home Network Prefix option [RFC5213], the
      IPv4 Home Address Request option [RFC5844], or the GRE Key option
      [RFC5845].  All the considerations from Section 5.3.3 of [RFC5213]
      MUST be followed when sending the bulk binding update request,
      with the exception related to the use of Mobile Node Group
      Identifier option in place of the individual session identifiers
      (Mobile Node Identifier option, Home Network Prefix option, GRE
      Key option, and IPv4 Home Address Request option).

   o  When requesting binding revocation for all the sessions that share
      the same bulk binding update group identifier, the mobile access
      gateway can choose to send a bulk revocation request.  To make
      such a request, it can send a Binding Revocation Indication
      message [RFC5846] to the local mobility anchor, including the
      Mobile Node Group Identifier option with the sub-type value of (1)
      (Bulk Binding Update Group).  The identifier value in the option
      MUST be set to the bulk binding update group identifier of the
      group for which bulk binding update operation is being requested.
      The message MUST NOT include any individual session identifiers
      such as the Mobile Node Identifier option [RFC4283], the Home
      Network Prefix option [RFC5213], the IPv4 Home Address Request
      option [RFC5844], or the GRE Key option [RFC5845].  All the



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      considerations from Section 9.2 of [RFC5846] MUST be followed when
      sending the bulk binding update request, with the exception
      related to the use of Mobile Node Group Identifier option in place
      of the individual session identifiers (Mobile Node Identifier
      option, Home Network Prefix option, GRE Key option, IPv4 Home
      Address Request option).

   o  Any time the mobile access gateway receives a Binding Revocation
      Indication message [RFC5846], with a Mobile Node Group Identifier
      option present in the request and with the sub-type value of (1)
      (Bulk Binding Update Group), this message serves as a bulk
      revocation request, with the request scope for revoking of all the
      mobility sessions that are part of that bulk binding update group
      specific to that local mobility anchor and identified by the group
      identifier in the Mobile Node Group Identifier option.

   o  All the considerations from [RFC5846] apply when processing a
      binding revocation request, except making the scope of the
      operation apply to a set of mobility sessions identified by the
      bulk binding update group identifier present in the request.

   o  If the received Binding Revocation Indication message includes the
      Mobile Node Identifier option [RFC4283], the Home Network Prefix
      option [RFC5213], the IPv4 Home Address Request option [RFC5844],
      or the GRE Key option [RFC5845], the mobile access gateway MUST
      consider this as an invalid message; it MUST reject the Binding
      Revocation Indication message and send a Binding Revocation
      Acknowledgement message with the Status field set to a value of
      128 (Binding Does NOT Exist).

5.2.  LMA Considerations

   The following are the considerations relevant to a local mobility
   anchor when supporting this specification.

5.2.1.  Extensions to Binding Cache Entry Data Structure

   The conceptual Binding Cache entry data structure maintained by the
   local mobility anchor, described in Section 5.1 of [RFC5213], is
   extended to include the following REQUIRED additional fields.

   o  MAG-Bulk-Binding-Update-Group-Id

      This is the bulk binding update group identifier assigned by the
      mobile access gateway for this mobility session.  It is a 32-bit
      unsigned integer.  This identifier is received in the Mobile Node
      Group Identifier option of the Proxy Binding Update message.  This




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      identifier is not globally unique within a Proxy Mobile IPv6
      domain; the same group identifier value may be used by other
      nodes.

   o  LMA-Bulk-Binding-Update-Group-Id

      This is the bulk binding update group identifier assigned by this
      local mobility anchor for this mobility session.  It is a 32-bit
      unsigned integer.  This identifier is not globally unique within a
      Proxy Mobile IPv6 domain; the same group identifier value may be
      used by other nodes.

5.2.2.  Enabling Bulk Binding Update Support for a Mobility Session

   The local mobility anchor will process a received Proxy Binding
   Update message as specified in [RFC5213].  However, if the (B) flag
   in the received Proxy Binding Update message is set to a value of (1)
   and if it includes a Mobile Node Group Identifier option with the
   sub-type value of (1) (Bulk Binding Update Group), the following
   processing takes place:

   o  If the (B) flag in the received Proxy Binding Update message is
      set to a value of (1) and if the Mobile Node Group Identifier
      option is present in the request, the message serves as a request
      to the local mobility anchor to enable bulk binding update support
      for that mobility session.

   o  Upon successful processing and acceptance of the Proxy Binding
      Update, the local mobility anchor can choose to enable bulk
      binding update support for this mobility session.  The decision
      whether to enable bulk binding update support for that mobility
      session is a matter of local policy and is controlled by the
      configuration variable
      AcceptBulkBindingUpdateReqForMobilitySession.

   o  For enabling the bulk binding update support for the mobility
      session, the local mobility anchor MUST associate the mobility
      session to a specific bulk binding update group locally.  The
      specific details on how the local mobility anchor associates the
      given mobility session to a specific bulk binding update group is
      outside the scope of this document.  The local mobility anchor can
      choose to assign a default bulk binding update group identifier
      value of (ALL-SESSIONS), indicating that all the mobility sessions
      from that mobile access gateway are part of that group.  The local
      mobility anchor SHOULD update the bulk binding update group
      identifier values in the Binding Cache entry, LMA-Bulk-Binding-
      Update-Group-Id and MAG-Bulk-Binding-Update-Group-Id, to the
      respective values.



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   o  If the bulk binding update support is enabled for the mobile
      node's mobility session, the local mobility anchor MUST send the
      assigned bulk binding update group identifier as part of the
      Mobile Node Group Identifier option, with the sub-type value of
      (1) (Bulk Binding Update Group) in the Proxy Binding
      Acknowledgement message that it sends to the mobile access
      gateway.  The (B) flag in the Proxy Binding Acknowledgement
      message MUST be set to value of (1).

   o  If the bulk binding update support is not enabled for the mobility
      session, the local mobility anchor MUST NOT include the Mobile
      Node Group Identifier option with the sub-type value of (1) (Bulk
      Binding Update Group), in the Proxy Binding Acknowledgement
      message that it sends to the mobile access gateway.  Furthermore,
      the (B) flag in the Proxy Binding Acknowledgement message MUST be
      set to value of (0).  It is to be noted that the Mobile Node Group
      Identifier option is a generic option and new sub-types may be
      defined by future specifications.

   o  If the received Proxy Binding Update message is not a bulk binding
      update request, (i.e., the (B) flag is set to a value of (0) and
      the Mobile Node Group Identifier option with the sub-type value of
      (1) (Bulk Binding Update Group) is not present), but is a request
      for extending the lifetime of an existing mobility session, for
      which the bulk binding update support is already enabled, then the
      local mobility anchor MUST process the request as specified in
      [RFC5213].  However, the value of (0) in the (B) flag in the
      message serves as a request for the local mobility anchor to
      disable bulk binding update support for that mobility session.
      Upon accepting the request, the local mobility anchor SHOULD set
      the parameters, LMA-Bulk-Binding-Update-Group-Id and MAG-Bulk-
      Binding-Update-Group-Id in the Binding Cache entry to a value of
      (0) and the mobility session MUST be excluded from any bulk
      binding update operations.

   o  Any time the local mobility anchor detects that the mobile node
      has roamed and changed its point of attachment to a new mobile
      access gateway, it SHOULD also update the bulk binding update
      group identifier of the mobility session.  Additionally, it should
      also update the existing group identifiers associated with that
      session.  As part of sending the Proxy Binding Acknowledgement to
      the new mobile access gateway, it MUST include the updated group
      identifier in the Mobile Node Group Identifier option, with a sub-
      type value of (1).  However, if the if the received Proxy Binding
      Update from the new mobile access gateway did not have the (B)
      flag set to a value of (1), then it MUST NOT include the mobility





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      session in any of bulk binding update group and MUST NOT include
      the Mobile Node Group Identifier option with the sub-type value of
      (1).

   o  Any time a mobile node's mobility session is de-registered by the
      mobile access gateway, or the session is revoked for
      administrative or any other reasons, the mobility session MUST
      also be removed from the bulk binding update group.

5.2.3.  Supporting Bulk Binding Updates

   The following section identifies the considerations for a local
   mobility anchor for performing bulk binding update and revocation
   operations with group-specific scope.

   o  Any time the local mobility anchor receives a Proxy Binding Update
      message with the (B) flag in the request set to a value of (0) and
      a Mobile Node Group Identifier option present in the request with
      sub-type value of (1) (Bulk Binding Update Group), the local
      mobility anchor MUST consider the request a bulk binding update
      request, with the request scope including all the mobility
      sessions that are part of that bulk binding update group, specific
      to that mobile access gateway, and identified by the group
      identifier in Mobile Node Group Identifier option.  However, if
      the received request also includes any individual session
      identifiers such as the Mobile Node Identifier option [RFC4283],
      the Home Network Prefix option [RFC5213], the IPv4 Home Address
      Request option [RFC5844], or the GRE Key option [RFC5845], the
      local mobility anchor MUST consider this as an invalid message; it
      MUST reject the Proxy Binding Update message and send a Proxy
      Binding Acknowledgement message with the Status field set to
      INVALID_MOBILE_NODE_GROUP_IDENTIFIER (Invalid group identifier
      value in the request).

   o  The local mobility anchor MUST consider the message as a request
      for extending the lifetime of all the mobility sessions that are
      associated with the group identifier in the Mobile Node Group
      Identifier option.  However, if the Mobile Node Group Identifier
      option with the sub-type value of (1) (Bulk Binding Update Group)
      has an unknown group identifier, then the local mobility anchor
      MUST reject the Proxy Binding Update message and send a Proxy
      Binding Acknowledgement message with the Status field set to
      INVALID_MOBILE_NODE_GROUP_IDENTIFIER (Invalid group identifier
      value in the request).

   o  Upon accepting the bulk binding update request, the local mobility
      anchor SHOULD extend the lifetime for all the mobility sessions
      that are part of the bulk binding update group identified by the



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      group identifier in the Mobile Node Group Identifier in the
      message.  Considerations from [RFC5213] MUST be applied for
      extending the lifetime of a mobile node's session.  It MUST also
      send a Proxy Binding Acknowledgement message with the Status field
      value set to 0 (Proxy Binding Update accepted).  The lifetime
      field in the message MUST be set to the allocated lifetime for all
      the mobility sessions.  The message MUST also include the Mobile
      Node Group Identifier option, with the sub-type value of (1) (Bulk
      Binding Update Group) and with the identifier value copied from
      the Mobile Node Group Identifier option present in the received
      Proxy Binding Update message.

   o  If the local mobility anchor rejects the bulk binding update
      request for any administrative reason, then it MUST NOT update the
      lifetime in the Binding Cache entries of any of the mobile nodes
      identified by the group identifier.  The local mobility anchor
      SHOULD send a Proxy Binding Acknowledgement indicating the reason
      for the rejection in the status code.

   o  Any time the local mobility anchor receives a Binding Revocation
      Indication Message [RFC5846] with a Mobile Node Group Identifier
      option present in the request and with the sub-type value of (1)
      (Bulk Binding Update Group), the local mobility anchor MUST
      consider the request as a bulk revocation request, with the
      request scope including all the mobility sessions that are part of
      the bulk binding update group specific to that mobile access
      gateway and identified by the group identifier in Mobile Node
      Group Identifier option.  However, if the received request also
      includes the Mobile Node Identifier option [RFC4283], the Home
      Network Prefix option [RFC5213], the IPv4 Home Address Request
      option [RFC5844], or the GRE Key option [RFC5845], the local
      mobility anchor MUST consider this as an invalid message; it MUST
      reject the Binding Revocation Indication message and send a BRA
      message with the Status field set to a value of 128 (Binding Does
      NOT Exist).  All the considerations from [RFC5846] apply when
      processing a binding revocation request, except making the scope
      of the operation apply to a set of mobility sessions identified by
      the group identifier present in the request.

   o  Upon accepting the Binding Revocation Indication request and
      completing the operation, the local mobility anchor MUST send a
      Binding Revocation Acknowledgement message with the Status field
      set to a value of 0 (success).  The message MUST include the
      Mobile Node Group Identifier option, with the identifier value
      copied from the Mobile Node Group Identifier option present in the
      received Binding Revocation Indication message.





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6.  Protocol Configuration Variables

6.1.  Local Mobility Anchor - Configuration Variables

   This specification adds a new configuration variable for the local
   mobility anchor.  The configured value for this variable is expected
   to survive server reboots and service restarts.

   AcceptBulkBindingUpdateReqForMobilitySession

      This flag indicates whether or not the local mobility anchor will
      accept the request from the mobile access gateway to enable bulk
      binding update support for the mobility session.  The default
      value for this flag is set to (1), indicating that it will accept
      the request from the mobile access gateway.  If the value of the
      flag is set to (0), the local mobility anchor will deny the
      request.

6.2.  Mobile Access Gateway - Configuration Variables

   This specification adds a new configuration variable for the mobile
   access gateway.  The configured value for this variable is expected
   to survive server reboots and service restarts.

   RequestBulkBindingUpdateSupportForMobilitySession

      This flag indicates whether or not the mobile access gateway will
      request the local mobility anchor to enable bulk binding update
      support for the mobility session.  The default value for this flag
      is set to (1), indicating that the mobile access gateway will set
      the bulk binding update flag (B) in the Proxy Binding Update
      request to a value of (1).  If the flag is set to a value of (0),
      the mobile access gateway will set the bulk binding update flag
      (B) in the Proxy Binding Update to a value of (0).

7.  IANA Considerations

   Per this document, IANA has done the following:

   o  Action-1: This specification defines a new flag (B) to the Proxy
      Binding Update message, specified in [RFC5213].  This flag is
      described in Section 4.1.  The value of the flag (B) has been
      allocated from the "Binding Update Flags" registry.

   o  Action-2: This specification defines a new flag (B) to the Proxy
      Binding Acknowledgement message, specified in [RFC5213].  This
      flag is described in Section 4.2.  The value of the flag (B) has
      been allocated from the "Binding Acknowledgement Flags" registry.



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   o  Action-3: This specification defines a new Mobility Header option,
      the Mobile Node Group Identifier option.  This option is described
      in Section 4.3.  The Type value for this option has been assigned
      in the same number space as allocated for the other mobility
      options [RFC6275].

   o  Action-4: The Sub-type field of the Mobile Node Group Identifier
      option introduces a new number space.  This number space is now
      managed by IANA, under the Registry, "Mobile Node Group Identifier
      Type Registry".  This specification reserves the sub-type value of
      (1) (Bulk Binding Update Group).  Approval of new sub-type values
      are to be made through IANA Expert Review.  The value range of
      this field is 0 through 255, but the values 0 and 255 are marked
      as reserved.  The remaining values 2-254 are available for
      allocation.

   o  Action-5: This document also defines a new status value
      INVALID_MOBILE_NODE_GROUP_IDENTIFIER (Invalid group identifier
      value in the request: 175) for use in the Proxy Binding
      Acknowledgement message, as described in Section 4.4.  This value
      has been assigned from the same number space as allocated for
      other status codes [RFC6275].

8.  Security Considerations

   The Mobile Node Group Identifier option defined in this specification
   is for use in Proxy Binding Update and Proxy Binding Acknowledgement
   messages.  This option is carried like any other mobility header
   option, and it does not require any other special security
   considerations.

   The bulk binding update and the bulk revocation operations specified
   in this document perform operations on a group of mobility sessions.
   If proper authorization checks are not in place, a malicious node may
   be able to hijack a mobile node's mobility session or may carry out a
   denial-of-service attack.  To prevent this attack, this specification
   requires the local mobility anchor to allow only authorized mobile
   access gateways to perform bulk operations.

9.  Acknowledgements

   The authors would like to specially thank Jouni Korhonen, Basavaraj
   Patil, Carlos Jesus Bernardos Cano, Dirk Von-Hugo, Pete Resnick, and
   Jari Arkko for reviewing this document and providing input.







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10.  References

10.1.  Normative References

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

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

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

   [RFC5846]  Muhanna, A., Khalil, M., Gundavelli, S., Chowdhury, K.,
              and P. Yegani, "Binding Revocation for IPv6 Mobility",
              RFC 5846, June 2010.

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

10.2.  Informative References

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

   [RFC5845]  Muhanna, A., Khalil, M., Gundavelli, S., and K. Leung,
              "Generic Routing Encapsulation (GRE) Key Option for Proxy
              Mobile IPv6", RFC 5845, June 2010.






















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Authors' Addresses

   Fuad Abinader (editor)
   Instituto Nokia de Tecnologia
   Av. Torquato Tapajos, 7200 - Km. 12 - Col Terra Nova
   Manaus, AM  69048-660
   Brazil

   EMail: fabinader@gmail.com


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

   EMail: sgundave@cisco.com


   Kent Leung
   Cisco
   170 West Tasman Drive
   San Jose, CA  95134
   USA

   EMail: kleung@cisco.com


   Suresh Krishnan
   Ericsson
   8400 Decarie Blvd.
   Town of Mount Royal, QC
   Canada

   Phone: +1 514 345 7900 x42871
   EMail: suresh.krishnan@ericsson.com


   Domagoj Premec
   Unaffiliated

   EMail: domagoj.premec@gmail.com








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