Internet DRAFT - draft-xia-mext-ha-init-flow-binding

draft-xia-mext-ha-init-flow-binding






Network Working Group                                             F. Xia
Internet-Draft                                               B. Sarikaya
Expires: October 22, 2011                                     Huawei USA
                                                          April 20, 2011


           Home Agent Initiated Flow Binding for Mobile IPv6
                 draft-xia-mext-ha-init-flow-binding-05

Abstract

   There are scenarios in which home agent initiated flow binding
   operations towards the mobile node is needed such as revoking a flow
   binding or moving a flow from one interface to another because of
   network resource availability.  This document defines one new
   Mobility Header, two messages, several actions and two new sub-
   options to perform home agent initiated interactions for flow
   bindings in a mobile node.  Home agent initiated flow bindings are
   supported for both IPv4 and IPv6 enabled mobile nodes.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on October 22, 2011.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   (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



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   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.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Use Cases  . . . . . . . . . . . . . . . . . . . . . . . . . .  3
     3.1.  Default Flow Binding Provisioning  . . . . . . . . . . . .  3
     3.2.  Flow Binding Revocation  . . . . . . . . . . . . . . . . .  4
     3.3.  Inter-Interface Flow Binding Movement  . . . . . . . . . .  4
     3.4.  Exceeding traffic quota  . . . . . . . . . . . . . . . . .  4
     3.5.  Real-time off-load . . . . . . . . . . . . . . . . . . . .  4
   4.  Protocol Operation . . . . . . . . . . . . . . . . . . . . . .  5
     4.1.  Adding flow bindings . . . . . . . . . . . . . . . . . . .  5
     4.2.  Deleting flow bindings . . . . . . . . . . . . . . . . . .  5
     4.3.  Modifying flow bindings  . . . . . . . . . . . . . . . . .  6
     4.4.  Refreshing flow bindings . . . . . . . . . . . . . . . . .  6
     4.5.  Moving flow bindings . . . . . . . . . . . . . . . . . . .  6
     4.6.  Switching flow bindings  . . . . . . . . . . . . . . . . .  7
     4.7.  Acknowledging flow bindings  . . . . . . . . . . . . . . .  7
     4.8.  Revoking flow bindings . . . . . . . . . . . . . . . . . .  7
     4.9.  Handling of the Flow Bindings List . . . . . . . . . . . .  8
   5.  Flow Binding Messages and Options  . . . . . . . . . . . . . .  9
     5.1.  Mobility Header  . . . . . . . . . . . . . . . . . . . . .  9
       5.1.1.  Flow Binding Indication  . . . . . . . . . . . . . . .  9
       5.1.2.  Flow Binding Acknowledgement . . . . . . . . . . . . . 11
       5.1.3.  Flow Binding Revocation Extensions . . . . . . . . . . 12
     5.2.  New Options  . . . . . . . . . . . . . . . . . . . . . . . 12
       5.2.1.  New Actions in Flow Identification Mobility Option . . 12
       5.2.2.  Alternate Home Agent sub-option  . . . . . . . . . . . 12
       5.2.3.  Target Care-of-Address sub-option  . . . . . . . . . . 13
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 14
   7.  IANA considerations  . . . . . . . . . . . . . . . . . . . . . 14
   8.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 14
     9.2.  Informative references . . . . . . . . . . . . . . . . . . 15
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16










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1.  Introduction

   [RFC6089] allows a mobile node to bind a particular flow to a care-of
   address without affecting other flows using the same home address.
   Binding Update (BU)/Binding Acknowledgement(BA) messages are extended
   for the mobile node to add, modify, remove and refresh flow binding
   in a home agent.  The operations are always initiated by the mobile
   node.

   In some cases, the home agent would like to initiate flow binding
   operations. e.g, the home agent revokes a flow binding for reasons
   such as accounting insufficiency of the mobile node; for the mobile
   node equipped with multiple interfaces, the home agent moves a flow
   binding from one interface to another based on network resource
   availability; the home agent provisions default flow binding rules to
   the mobile node based on the mobile node's default profile.

   This document defines one new Mobility Header and two new messages
   for the home agent to control flow bindings in the mobile node.  Flow
   mobility for the mobile nodes with IPv4 home address and IPv4 address
   of the home agent as described in [RFC5555] is also supported.


2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

   The terminology in this document is based on the definitions in
   [RFC3775] and [RFC6089].


3.  Use Cases

3.1.  Default Flow Binding Provisioning

   Michael purchases a dual mode phone equipped with both 3GPP and WiFi
   interfaces.  He also signs a Service Level Agreement(SLA) with an
   operator including the following information:

   o  3GPP access takes priority over WiFi access when providing Voice-
      over-IP (VoIP) service.  That is, the 3GPP network is always used
      when Michael makes a call if the network is accessible.
   o  WiFi access is primarily selected to serve IPTV service.
   o  Peer-to-peer (p2p) download is only allowed through WiFi access.

   Michael's default profile can be downloaded from AAA server through



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   the home agent to its mobile node when registering.

3.2.  Flow Binding Revocation

   For administrative reasons, such as the utilization of CPU of a home
   agent reaches a threshold or the home agent needs to reboot some of
   it line cards, sometimes it becomes necessary to inform the mobile
   node that its flow binding has been revoked and the mobile node is no
   longer able to receive IP mobility service for a given flow.  Apart
   from revocation, the home agent may decide to delete a flow binding
   with a delete operation.

3.3.  Inter-Interface Flow Binding Movement

   Michael stays home using WLAN access for voice call and downloading.
   However, the operator does its routine maintenance of its WiFi
   devices.  The operator then moves all the calls and downloading to
   its 3GPP interface.  Once the maintenance is over, the operator then
   moves back the service.

3.4.  Exceeding traffic quota

   The 3G operator offers a mobile broadband service with a flat rate
   subscription limited to 5G Byte per month.  Once the quota is reached
   the service is downgraded to 64 K bit per second.  This limitation
   does not prevent the user from using the 3G access for mobile
   broadband services and there is no reason for the operator to change
   the policy since the service is still available.  However, since the
   operator has more information available than the user, the operator
   can indicate this to the user by sending modified flow descriptors to
   the user as a proposal to change access for an ongoing session.

   Please observe that there is no need for the HA to say which
   interface to use.  The operator may have this information, but if no
   such information is available then sending an existing flow
   descriptor excluding the BID could serve as an indication for the
   mobile node to take action and change access for a specific flow.

3.5.  Real-time off-load

   The 3G operator may want to move traffic flows from the 3G access to
   another access due to increased traffic load in the 3G access network
   and a need to ensure that bandwidth is available for prioritized
   services.  Hence, already established sessions are moved by the home
   agent by sending down an updated flow descriptor to the mobile node.

   As for the previous scenario there is no need for the HA to say which
   interface to use.



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4.  Protocol Operation

   [RFC6089] makes use of Binding Update (BU) /Binding
   Acknowledgement(BA) signalling to forward, i.e. register or discard a
   flow binding in a home agent.  That is, flow binding operations are
   always initiated from the mobile node.  The mechanism specified in
   this document is complimentary to the method described in [RFC6089].
   It is assumed that the home agent has already created Binding Cache
   entries for the mobile node before launching flow binding operations.

   In this document, one new Mobility Header and two new messages are
   defined, that is, Flow Binding Indication (FBI) Section 5.1.1 and
   Flow Binding Acknowledgement (FBA)Section 5.1.2.  FBI is used by the
   home agent to initiate flow binding operations, while FBA is used for
   acknowledging FBI.

4.1.  Adding flow bindings

   Adding the flow binding implies associating a flow with a particular
   care-of address for the mobile node.  The care-of address concerned
   with the flow binding is present in the destination address of the
   packet or the alternate care-of address option.  Alternatively, the
   care-of address may be indicated by the Target Care-of Address sub-
   option defined in Section 5.2.3.  Binding Identification number (BID)
   described in [RFC5648] is not used in the flows initiated by the home
   agent.

   When adding a new flow binding, the home agent sends a FBI with a
   Flow Identification Mobility option to the mobile node.  The Flow
   Identification Mobility option defined in [RFC6089] includes a unique
   Flow Identifier (FID).  The Action field of the option MUST indicate
   an Add operation defined in Section 5.2.1.  The FID needs only be
   unique for the receiver of the message that adds a flow, i.e. the
   same FID can be used across different receivers of the message.  A
   lifetime value is included to indicate the remaining lifetime of the
   flow binding.

4.2.  Deleting flow bindings

   When removing a flow binding, the home agent node sends a FBI with a
   Flow Identification Mobility option in which Action field indicates
   Delete operation.  The Flow Identification Mobility option includes a
   unique FID for the mobile node to locate the flow binding and remove
   it.

   The trigger for the delete operation is MN sending a BU with Flow
   Identification Mobility Option that registers a new flow.  Using the
   delete operation the home agent revokes the new flow registered by



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   MN.

4.3.  Modifying flow bindings

   When modifying a flow binding (either the care-of address or other
   attributes of the flow), the home agent sends the mobile node a FBI
   message with Flow Identification Mobility option.  The option
   includes the FID for the binding being modified.  A Traffic Selector
   sub-option may come with the Flow Identification Mobility Option and
   contain the new attributes needed to classify the flow such as in
   [RFC6088].  Hence, flow modification is essentially a process where
   an existing flow definition is removed and a new flow (included in
   the option) is added and given the same FID as the flow that was
   removed.

4.4.  Refreshing flow bindings

   A flow binding is refreshed by simply including the Flow
   Identification Mobility option with Refresh Action field in the FBI
   message.  The message should be sent before the expiration of the
   flow binding.  The message updates existing bindings with new
   information.  Hence, all information previously sent in the last
   refreshing message need to be resent, otherwise such information will
   be lost.

4.5.  Moving flow bindings

   The home agent can move a flow associated to one interface of the
   multi-interfaced mobile node to another by sending a FBI message to
   the mobile node.  A Flow Identification Mobility option whose Action
   field is set to Move is included.  The address of the target
   interface is also included in the Flow Identification Mobility option
   in Target Care-of Address sub-option.

   In some cases the mobile node manually decides to move an IP Flow
   from one interface, e.g. 3GPP to another e.g.  WLAN.  The home agent
   receives such a request to forward a flow and performs the action.
   We recognize that the manual intervention is always possible and
   generally has precedence to other policies.  On such a flow HA-
   initiated move operation SHOULD not be used.  If used, MN will move
   it back and a set of ping-pong move operations will take place.  Home
   agent SHOULD move such a flow only if network conditions require it
   to be moved such as congestion on the current interface because such
   conditions can best be detected by the home agent only and not by the
   mobile nodes.






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4.6.  Switching flow bindings

   Here are some example scenarios where a home agent signal to the
   mobile node that it should acquire a new home agent for some specific
   flows:
   o  The home agent is overloaded.
   o  An operator may wish to balance the load among home agents.
   o  Operators do periodic maintenance in order to maintain reliability
      [I-D.ietf-mip6-hareliability].
   o  Some other scenarios.

   The home agent sends the mobile node a FBI with Flow Identification
   Mobility Option to indicate that the mobile node should bind a flow
   to a new home agent.  The alternative home agent addresses are
   included for the mobile node to initiate the flow binding to a new
   home agent.

   The switch operation is similar to hard switch described in
   [I-D.ietf-mip6-hareliability] where standby and active home agents
   have different IP addresses.  In the switch operation both home
   agents continue to serve the mobile node using the same Home Address
   while in hard switch the active home agent stops serving and the
   standby home agent takes over.

4.7.  Acknowledging flow bindings

   The mobile node sends FBA message to acknowledge the reception of FBI
   to Add, Delete, Modify, Refresh, Move, or Switch a flow binding.  On
   receiving messages with Flow Identification Mobility Option(s), the
   mobile node should copy each Flow Identification Mobility Option to
   the Acknowledgement messages.

4.8.  Revoking flow bindings

   Home agent revokes a flow binding registration by the mobile node,
   i.e. flow identification mobility option sent by MN with action set
   to forward.  One possible reason is the home agent is overloaded.
   There could be other reasons.

   HA sends Binding Revocation Indication message defined in [RFC5846]
   extended with flow identification mobility option.  HA includes the
   flow identification mobility option received from MN.  HA sets the
   action field to Revoke.

   MN MUST send a Binding Revocation Acknowledgement message defined in
   [RFC5846] to indicate that it has received Binding Revocation
   Indication message.  If MN accepts the Binding Revocation Indication
   message it MUST set the status code to 0 for success or to 1 for



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   partial success as described in [RFC5846].

4.9.  Handling of the Flow Bindings List

   Flow bindings list defined in [RFC6089] needs to be modified after
   each protocol operation defined above as follows:

   If FBI contains a flow binding add operation and if the corresponding
   FBA has a status code equal to zero, home agent MUST add a new entry
   to the flow bindings list.  FID, Flow Descriptor, FID-PRI and Action
   fields are taken from the Flow Identification Mobility Option.  BID
   is copied from the Binding Reference sub-option.  Active/Inactive
   Flag is set to Active.  Note that if BID is not available it may be
   replaced by Care-of-Address.

   If FBI contains a flow binding delete operation and if the
   corresponding FBA has a status code equal to zero, home agent MUST
   locate the list entry corresponding to this flow and then delete the
   entry.

   If the home agent sends a Binding Revocation Indication message with
   Flow Mobility Option where the action field is set to Revoke and if
   the corresponding Binding Revocation Acknowledgement message
   indicates acceptance, home agent MUST locate the list entry
   corresponding to this flow and then delete the entry.

   If FBI contains a flow binding modify operation and if the
   corresponding FBA has a status code equal to zero, home agent MUST
   delete the list entry corresponding to this flow and then add a new
   entry setting the values as defined in the Flow Identification
   Mobility Option.

   If FBI contains a flow binding refresh operation and if the
   corresponding FBA has a status code equal to zero, home agent MUST
   locate the list entry corresponding to this flow and then set Active/
   Inactive Flag to Active.

   If FBI contains a flow binding move operation and if the
   corresponding FBA has a status code equal to zero, home agent MUST
   locate the list entry corresponding to this flow and then change the
   BID value to the Care-of-Address in the Flow Identification Mobility
   Option.

   If FBI contains a flow binding switch operation and if the
   corresponding FBA has a status code equal to zero, home agent MUST
   locate the list entry corresponding to this flow and then delete the
   entry.




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   Flow binding operations apply equally to IPv6 packets as well as IPv4
   packets as in Dual-Stack Mobile IPv6 [RFC5555].


5.  Flow Binding Messages and Options

5.1.  Mobility Header

   The messages described below follow the Mobility Header format
   specified in Section 6.1 of [RFC3775]:


       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Payload Proto |  Header Len   |   MH Type     |   Reserved    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |           Checksum            |                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
       |                                                               |
       .                                                               .
       .                       Message Data                            .
       .                                                               .
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                         Figure 1: Mobility Header

5.1.1.  Flow Binding Indication

   The Flow Binding Indication messages are used by the home agent to
   initiate flow binding operations to the mobile node.  The Flow
   Binding Indication messages use the MH Type value (IANA-TBD1) for
   Flow Binding message and a Flow Binding Type value of 1, and the
   format of the Message Data field in the Mobility Header is as
   follows:
















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       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
                                       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                       |      Flow Binding Type = 1    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |          Sequence #           |   Trigger     |A|  Reserved   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
       .                                                               .
       .                        Mobility options                       .
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


              Figure 2: Flow Binding Indication Message Type

   Sequence #

      A 16-bit unsigned integer used by the home agent to match a
      returned Flow Binding Acknowledgement with this Flow Binding
      Indication.  It could be a random number.
   Trigger

      8-bit unsigned integer indicating the event which triggered the
      home agent to send the Flow Binding Indication message.  The
      following Trigger values are currently defined:
   0  Reserved
   1  Unspecified
   2  Administrative Reason
   3  Possible Out-of Sync BCE State
   250-255 Reserved For Testing Purposes only
   All other values are Reserved

   Acknowledge (A)

      The Acknowledge (A) bit is set by the home agent to request a Flow
      Binding Acknowledgement be returned upon receipt of the Flow
      Binding Indication.
   Reserved

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

      Variable-length field of such length that the complete Mobility
      Header is an integer multiple of 8 octets long.  Flow
      Identification Mobility Options are included in this field.




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5.1.2.  Flow Binding Acknowledgement

   The Flow Binding Acknowledgement is used to acknowledge receipt of a
   Flow Binding Indication.  The Flow Binding Acknowledgement has the MH
   Type value (IANA-TBD1) for Flow Binding message and a Flow Binding
   Type value of 2.  When this value is indicated in the MH Type field,
   the format of the Message Data field in the Mobility Header is as
   follows:


       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
                                       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                       |       Flow Binding Type = 2   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |          Sequence #           |   Status      |    Reserved   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
       .                                                               .
       .                        Mobility options                       .
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


            Figure 3: Flow Binding Acknowledgement Message Type

   Sequence #

      The sequence number in the Flow Binding Acknowledgement is copied
      from the Sequence Number field in the Flow Binding Indication.
   Status

      8-bit unsigned integer indicating the result of processing the
      Flow Binding Indication message by the receiving mobile node.
      Values of the Status field less than 128 indicate that the Flow
      Binding Indication was processed successfully by the receiving
      node.  Values greater than or equal to 128 indicate that the Flow
      Binding Indication was rejected by the receiving node.  The
      following status values are currently defined:
   0  success
   1  partial success
   128  Binding Does NOT Exist
    All other values are Reserved
   Mobility Options

      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.  Flow



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      Identification Mobility Options are included in this field.

5.1.3.  Flow Binding Revocation Extensions

   This specification enables Binding Revocation Indication and Binding
   Revocation Acknowledgement messages to carry Flow Identification
   Mobility Options as defined in [RFC6089] with extensions defined in
   this document.

5.2.  New Options

5.2.1.  New Actions in Flow Identification Mobility Option

   This specification defines new actions to be carried in Action
   parameter of the Flow Identification Mobility Option defined in
   [RFC6089].
   Action

      This is a 8-bit field that describes the required processing for
      the option.  It can be assigned one of the following new values in
      addition to 0-2 already assigned:
   11  Add a flow binding
   12  Delete a flow binding
   13  Modify  a flow binding
   14  Refresh  a  flow binding
   15  Move a flow binding
   16  Switch a flow binding  to alternative home agents
   17  Revoke a flow binding
   All other values are reserved

5.2.2.  Alternate Home Agent sub-option

   This section introduces the Alternate Home Agent sub-option, which
   may be included in the Flow Identification Mobility option.  This
   sub-option is used to indicate the mobile node to switch a flow
   binding from one home agent to another.


       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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |Sub-opt Type   | Sub-opt Len   | # of Addresses|    Reserved   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                 Home Agent Addresses                          |
       .                                                               .
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+





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                 Figure 4: Alternate Home Agent Sub-option

   Sub-opt Type

      To be assigned by IANA
   Sub-opt Len

      Length of the sub-option in 8-octet units
   # of Addresses

      The number of home agent addresses in this option.
   Reserved

      This field is unused.  It MUST be initialized to zero by the
      sender and MUST be ignored by the receiver.
   Home Agent Addresses

      Alternative home agent addresses to which the mobile node is going
      to switch its flow bindings.  Home agent addresses could be IPv4
      or IPv6 addresses.

5.2.3.  Target Care-of-Address sub-option

   This section introduces the Target Care-of-Address, which may be
   included in the Flow Identification Mobility Option.  This sub-option
   is used to indicate the mobile node to move a flow binding from one
   interface to another.


       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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |Sub-opt Type   | Sub-opt Len   |          Reserved             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                 Target Care-of-Address                        |
       .                                                               .
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                Figure 5: Target Care-of-Address Sub-option

   Sub-opt Type

      To be assigned by IANA







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   Sub-opt Len

      Length of the sub-option in 8-octet units
   Reserved

      This field is unused.  It MUST be initialized to zero by the
      sender and MUST be ignored by the receiver.
   Target Care-of-Address

      The address of an interface that the flow is moved to.  This
      address could be IPv4 or IPv6 address.


6.  Security Considerations

   TBD.


7.  IANA considerations

   TBD.


8.  Acknowledgements

   TBD.


9.  References

9.1.  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.

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

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

   [RFC4862]  Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
              Address Autoconfiguration", RFC 4862, September 2007.

   [RFC0792]  Postel, J., "Internet Control Message Protocol", STD 5,



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              RFC 792, September 1981.

   [RFC4443]  Conta, A., Deering, S., and M. Gupta, "Internet Control
              Message Protocol (ICMPv6) for the Internet Protocol
              Version 6 (IPv6) Specification", RFC 4443, March 2006.

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

   [RFC6089]  Tsirtsis, G., Soliman, H., Montavont, N., Giaretta, G.,
              and K. Kuladinithi, "Flow Bindings in Mobile IPv6 and
              Network Mobility (NEMO) Basic Support", RFC 6089,
              January 2011.

9.2.  Informative references

   [I-D.ietf-mip6-hareliability]
              Wakikawa, R., "Home Agent Reliability Protocol (HARP)",
              draft-ietf-mip6-hareliability-08 (work in progress),
              November 2010.

   [I-D.ietf-mext-nemo-v4traversal]
              Soliman, H., "Mobile IPv6 Support for Dual Stack Hosts and
              Routers", draft-ietf-mext-nemo-v4traversal-10 (work in
              progress), April 2009.

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

   [RFC6088]  Tsirtsis, G., Giarreta, G., Soliman, H., and N. Montavont,
              "Traffic Selectors for Flow Bindings", RFC 6088,
              January 2011.

















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Authors' Addresses

   Frank Xia
   Huawei USA
   1700 Alma Dr. Suite 500
   Plano, TX  75075

   Phone: +1 972-509-5599
   Email: xiayangsong@huawei.com


   Behcet Sarikaya
   Huawei USA
   1700 Alma Dr. Suite 500
   Plano, TX  75075

   Phone: +1 972-509-5599
   Email: sarikaya@ieee.org

































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