Flow Binding Support for Mobile IP
draft-ietf-mip4-multiple-tunnel-support-07

Mobility for IPv4 Working Group                       S. Gundavelli, Ed.
Internet-Draft                                                  K. Leung
Intended status: Standards Track                                   Cisco
Expires: June 26, 2014                                       G. Tsirtsis
                                                                Qualcomm
                                                              H. Soliman
                                                    Elevate Technologies
                                                             A. Petrescu
                                                                CEA LIST
                                                       December 23, 2013

                   Flow Binding Support for Mobile IP
             draft-ietf-mip4-multiple-tunnel-support-07.txt

Abstract

   This specification defines extensions to Mobile IP protocol for
   allowing a mobile node with multiple interfaces to register a care-of
   address for each of its network interfaces and to simultaneously
   establish multiple IP tunnels with its home agent.  This essentially
   allows the mobile node to utilize all the available network
   interfaces and build an higher aggregated logical pipe with its home
   agent for its home address traffic.  Furthermore, these extensions
   also allow the mobile node and the home agent to negotiate flow
   policies for binding individual traffic flows with the registered
   care-of addresses.

Status of This Memo

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

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on June 26, 2014.

Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the

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   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
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Conventions & Terminology  . . . . . . . . . . . . . . . . . .  3
     2.1.  Conventions  . . . . . . . . . . . . . . . . . . . . . . .  3
     2.2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Solution Overview  . . . . . . . . . . . . . . . . . . . . . .  4
     3.1.  Example Call Flow  . . . . . . . . . . . . . . . . . . . .  5
   4.  Message Extensions . . . . . . . . . . . . . . . . . . . . . .  6
     4.1.  Multipath Extension  . . . . . . . . . . . . . . . . . . .  6
     4.2.  Flow-Binding Extension . . . . . . . . . . . . . . . . . .  9
     4.3.  New Error Codes for Registration Reply . . . . . . . . . . 11
   5.  Protocol Operation . . . . . . . . . . . . . . . . . . . . . . 11
     5.1.  Mobile Node Considerations . . . . . . . . . . . . . . . . 11
     5.2.  Home Agent Considerations  . . . . . . . . . . . . . . . . 13
   6.  Routing Considerations . . . . . . . . . . . . . . . . . . . . 14
   7.  Protocol Configuration Variables . . . . . . . . . . . . . . . 14
   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 15
   9.  Security Considerations  . . . . . . . . . . . . . . . . . . . 15
   10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 16
   11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 16
   12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16
     12.1. Normative References . . . . . . . . . . . . . . . . . . . 16
     12.2. Informative References . . . . . . . . . . . . . . . . . . 17

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1.  Introduction

   With the ubiquitous availability of wireless networks supporting
   different access technologies, mobile devices are now equipped with
   multiple wireless interfaces and have the ability to connect to the
   network over any of those interfaces and access the network.  In many
   deployments, it is desirable for a mobile node to leverage all the
   available network connections and have IP mobility support for its IP
   sessions.

   The operation defined in the Mobile IP Protocol [RFC5944], allows a
   mobile node to continue to use its home address as it moves around
   the internet.  Based on the mode of operation, there will be a Mobile
   IP tunnel that will be established between the home agent and the
   mobile node, or between the home agent and the foreign agent where
   the mobile node is attached.  In both of these modes, there will only
   be one interface on the mobile node that is receiving the traffic
   from the home agent.  However, this is not efficient and requires an
   approach where the mobile node can use more than one interfaces for
   reaching the home network.  The objective being efficient use of all
   available links to obtain higher aggregated bandwidth for the
   tunneled traffic between the home agent and the mobile node.

   This specification defines extensions to Mobile IPv4 protocol for
   allowing a mobile node with multiple interfaces to register a care-of
   address for each of its network interfaces and to simultaneously
   establish multiple IP tunnels with its home agent.  Furthermore, this
   specification also defines extensions to allow the mobile node and
   the home agent to optionally negotiate flow policies for binding
   individual traffic flows with the registered care-of addresses.

2.  Conventions & 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 [RFC5944] and [RFC3753].  In addition this
   document uses the following terms.

   Binding Identifier (BID)

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      It is an identifier for a specific binding of a mobile node.  A
      binding defines an association between a mobile node's home
      address and its registered care-of address.  A mobile node, when
      it registers multiple bindings with its home agent, each using
      different care-of addresses, then each of those bindings are given
      a unique identifier.  The Binding Identifier is unique within all
      the bindings for a given mobile node.

   Flow Identifier (FID)

      It is an identifier for a given IP flow, uniquely identified by
      source address, destination address, protocol type, source port
      and destination port.  In the context of this document, the IP
      flows associated with a mobile node are the IP flows using its
      home address.

3.  Solution Overview

   The illustration below in Figure-1 is of a mobile node attached to
   the network over three different access technologies, Wi-Fi, LTE and
   CDMA.  The mobile node is assigned an home address, HoA-1, and has
   configured the care-of addresses CoA-1 (Wi-Fi), CoA-2 (LTE) and CoA-3
   (CDMA).  The mobile node has registered the three care-of addresses
   with the home agent and has established Mobile IP tunnels, Tunnel-1,
   Tunnel-2 and Tunnel-3 over each of those access networks.  The IP
   traffic using mobile node's home address (HoA-1) can be routed
   through any of the three tunnel paths.  The mobile node's IP flows,
   Flow-1, Flow-2 and Flow-3 are routed between the home agent and the
   mobile node over these different Mobile IP tunnels based on the
   negotiated flow policy.

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   Flow-1
    |
    |Flow-2
    | |
    | |Flow-3              _----_
    | | |         CoA-1  _(      )_   Tunnel-1
    | | |    .---=======(   Wi-Fi  )========\ Flow-1
    | | |    |           (_      _)          \
    | | |    |             '----'             \
    | | | +=====+          _----_              \  +=====+    _----_
    | | '-|     | CoA-2  _(      )_ Tunnel-2    \ |     |  _(      )_ --
    | '---| MN  |---====(   LTE    )=========-----| HA  |-( Internet )--
    '-----|     |        (_      _)      Flow-3 / |     |  (_      _) --
          +=====+          '----'              /  +=====+    '----'
           | |             _----_             /
    HoA-1--' |    CoA-3  _(      )_ Tunnel-3 /
             .------====(   CDMA   )========/ Flow-2
                         (_      _)
                           '----'

       Figure 1: Mobile Node with multiple tunnels to the home agent

   The above table is an example of how the individual flows are bound
   to different care-of addresses registered with the home agent.

   +-------+----------------------+------------------------------------+
   | Flow  | CoA/Tunnel/BID       | Negotiated Flow Policy             |
   | Id    |                      |                                    |
   +-------+----------------------+------------------------------------+
   | 1.    | CoA-1/Tunnel-1/BID-1 | All SIP Flows over WiFI            |
   | 2.    | CoA-2/Tunnel-2/BID-2 | All HTTP Flows over LTE            |
   | 3.    | CoA-3/Tunnel-3/BID-3 | All SSH Flows over CDMA            |
   +-------+----------------------+------------------------------------+

                   Table 1: Example - Flow Binding Table

3.1.  Example Call Flow

   Figure 2 shows a scenario where a mobile node is attached two WLAN
   and LTE access networks negotiates multipath support with the home
   agent.  Furthermore, the mobile node and the home agent also
   negotiate the flow policies which bind specific application traffic
   to specific access networks.

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      +-------+          +-------+          +-------+          +-------+
      |   MN  |          | WLAN  |          |  LTE  |          |  HA   |
      |       |          |Network|          |Network|          |       |
      +-------+          +-------+          +-------+          +-------+
         |                   |                  |                  |

   * MIP Registration of the Care-of Address obtained from WLAN Network

         |<--- (1) --------->|                  |                  |
         |                   |   RRQ (Multipath, Flow-Binding)     |
         |---- (2) ----------------------------------------------->|
         |                   |   RRP            |                  |
         |<--- (3) ------------------------------------------------|
         |              MIP Tunnel through WLAN Network            |
         |=====(4)===========*=====================================|

   * MIP Registration of the Care-of Address obtained from LTE Network

         |<--- (5) ---------------------------->|                  |
         |                   |  RRQ (Multipath, Flow-Binding)      |
         |---- (6) ----------------------------------------------->|
         |                   |  RRP             |                  |
         |<--- (7) ------------------------------------------------|
         |              MIP Tunnel through LTE Access              |
         |=====(8)==============================*==================|
         |                                                         |
         *                                                         *
   (Policy-based Routing Rule)               (Policy-based Routing Rule)

                Figure 2: Multipath Negotiation - Call Flow

4.  Message Extensions

   This specification defines the following new extensions to Mobile IP.

4.1.  Multipath Extension

   This extension is used for requesting multipath support.  It
   indicates that the sender is requesting the home agent to register
   the current care-of address listed in this Registration Request as
   one of the many care-addresses through which the mobile node can be
   reached.  It is also for carrying the information specific to the
   interface to which the care-of addresses that is being registered is
   bound.

   This extension is a non-skippable extension and MAY be added by the

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   mobile node to the Registration Request message.  There MUST NOT be
   more than one instance of this extension present in the message.
   This extension MUST NOT be added by the home agent or by the foreign
   agent either to the Registration Request or to the Registration
   Reply.

   This extension should be protected using the Mobile-Home
   Authentication extension [RFC5944].  As specified in Section 3.2 and
   Section 3.6.1.3 of [RFC5944], the mobile node MUST place this
   Extension before the Mobile-Home Authentication Extension in the
   registration messages, so that this extension is integrity protected.

   The format of this extension is as shown below.  It adheres to the
   short extension format described in [RFC5944].

        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   |   If-ATT      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |   If-Label    |   Binding-Id  |B|O|       Reserved            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                       Figure 3: Multipath Extension

      Type

         Type: <IANA-1>

      Length

         The length of the extension in octets, excluding Type and
         Length fields.  This field MUST be set to value of 6.

      Sub-Type

         This field MUST be set to a value of 1 (Multipath Extension).

      Interface Access-Technology Type (If-ATT)

         This 8-bit field identifies the Access-Technology type of the
         interface through which the mobile node is connected.  The
         permitted values for this are from the Access Technology Type
         registry defined in [RFC5213].

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      Interface Label (If-Label)

         This 8-bit field represents the interface label represented as
         an unsigned integer.  The mobile node identifies the label for
         each of the interfaces through which it registers a CoA with
         the home agent.  When using static traffic flow policies on the
         mobile node and the home agent, the label can be used for
         generating forwarding policies.  For example, the operator may
         have policy which binds traffic for Application "X" needs to
         interface with Label "Y".  When a registration through an
         interface matching Label "Y" gets activated, the home agent and
         the mobile node can dynamically generate a forwarding policy
         for forwarding traffic for Application "X" through mobile IP
         tunnel matching Label "Y".  Both the home agent and the mobile
         node can route the Application-X traffic through that
         interface.  The permitted values for If-Label are 1 through
         255.

      Binding-Identifier (BID)

         This 8-bit field is used for carrying the binding identifier.
         It uniquely identifies a specific binding of the mobile node,
         to which this request can be associated.  Each binding
         identifier is represented as an unsigned integer.  The
         permitted values are 1 through 254.  The BID value of 0 and 255
         are reserved.  The mobile node assigns a unique value for each
         of its interfaces and includes them in the message.

      Bulk Re-registration Flag (B)

         This flag, if set to a value of (1), is to notify the home
         agent to consider this request as a request to update the
         binding lifetime of all the mobile node's bindings, upon
         accepting this specific request.  This flag MUST NOT be set to
         a value of (1), if the value of the Registration Overwrite Flag
         (O) flag is set to a value of (1).

      Registration Overwrite (O)

         This flag, if set to a value of (1), notifies the home agent
         that upon accepting this request, it should replace all of the
         mobile node's existing bindings with this binding.  This flag
         MUST NOT be set to a value of (1), if the value of the Bulk Re-
         registration Flag (B) is set to a value of (1).  This flag MUST
         be set to a value of (0), in de-registration requests.

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      Reserved (R)

         This 14-bit field is unused for now.  The value MUST be
         initialized to (0) by the sender and MUST be ignored by the
         receiver.

4.2.  Flow-Binding Extension

   This extension contains information that can be used by the mobile
   node and the home agent for binding mobile node's IP flows to a
   specific multipath registration.  There can be more than one instance
   of this extension present in the message.

   This extension is a non-skippable extension and MAY be added to the
   Registration Request by the mobile node, or by the home agent to the
   Registration Reply.  There MUST NOT be more than one instance of this
   extension present in the message.  This extension MUST NOT be added
   by the foreign agent either to the Registration Request or to the
   Registration Reply.

   This extension should be protected by Mobile-Home Authentication
   extension [RFC5944].  As specified in Section 3.2 and Section 3.6.1.3
   of [RFC5944], the mobile node MUST place this Extension before the
   Mobile-Home Authentication Extension in the registration messages, so
   that this extension is integrity protected.

   The format of this extension is as shown below.  It adheres to the
   long extension format described in [RFC5944].

        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      |  Sub-Type     |           Length              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    Action     |  BID Count   |        ...   BID List   ...    ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |   TS Format   |             Traffic Selector                  ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     Figure 4: Flow-Binding Extension

      Type

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         Type: <IANA-2>

      Sub-Type

         This field MUST be set to a value of 1 (Flow-Binding
         Extension).

      Length

         The length of the extension in octets, excluding Type, Length
         and Sub-Type fields.

      Action

   +---------+-------+-------------------------------------------------+
   | Action  | Value | Comments                                        |
   +---------+-------+-------------------------------------------------+
   | Drop    | 0     | Drop matching packets.  A filter rule           |
   |         |       | indicating a drop action MUST include a single  |
   |         |       | BID byte, the value of which MAY be set to 255  |
   |         |       | by the sender and the value of which SHOULD be  |
   |         |       | ignored by the receiver.                        |
   | Forward | 1     | Forward matching packets to the 1st BID in the  |
   |         |       | list of BIDs the filter rule is pointing to.    |
   |         |       | If the 1st BID becomes invalid (i.e., the       |
   |         |       | corresponding CoA is deregistered) use the next |
   |         |       | BID in the list.                                |
   +---------+-------+-------------------------------------------------+

                 Table 2: Action Rules for the Traffic Selector

      BID Count

         Total number of binding identifiers that follow this field.
         Permitted value for this field are 1 through 8; Each binding
         identifier is represented as an unsigned integer in a single
         octet field.  There is no delimiter between two binding
         identifier values, they are spaced consecutively.

      TS Format

         An 8-bit unsigned integer indicating the Traffic Selector
         Format.  Value (0) is reserved and MUST NOT be used.  When the
         value of TS Format field is set to (1), the format that follows
         is the IPv4 Binary Traffic Selector specified in section 3.1 of
         [RFC6088], and when the value of TS Format field is set to (2),

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         the format that follows is the IPv6 Binary Traffic Selector
         specified in section 3.2 of [RFC6088].

      Traffic Selector

         A variable-length opaque field for including the traffic
         specification identified by the TS format field.  It identifies
         the traffic selectors for matching the IP traffic and binding
         them to specific binding identifiers.

4.3.  New Error Codes for Registration Reply

   This document defines the following error code values for use by the
   home agent in the Code field of the Registration Reply.

   MULTIPATH_NOT_ALLOWED (Multipath Support not allowed for this
   mobility session): <IANA-3>

   INVALID_FB_IDENTIFIER (Invalid Flow Binding Identifier): <IANA-4>

5.  Protocol Operation

5.1.  Mobile Node Considerations

   The configuration variable, EnableMultipathSupport, determines if
   multipath support is enabled or disabled on the mobile node.  If
   multipath support is not enabled, then this specification does not
   apply.  If multipath support is enabled on a mobile node, then the
   following considerations apply.

   o  The mobile node should register a care-of address for each of the
      active egress interfaces that it wishes to register with the home
      agent.  It can do so by sending a Registration Request to the home
      agent through each of those interfaces.

   o  Each of the Registration Requests that is sent MUST include the
      care-of address of the respective interface.  The Registration
      Request has to be routed through the specific interface for which
      the registration is sough for.  Some of these interfaces may be
      connected to networks with a configured foreign agent on the link
      and in such foreign agent based registrations, the care-of address
      MUST be the address of the foreign agent.

   o  A Multipath extension Section 4.1 reflecting the interface
      parameters MUST be present in each of the Registration Requests.
      This serves as an indication to the home agent that the
      Registration Request is a Multipath registration and the home
      agent MUST register this care-of address as one of the many

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      care-of addresses through which the mobile node's home address is
      reachable.  The mobile node MUST place this Extension before the
      Mobile-Home Authentication Extension in the Registration Request
      message.

   o  If the mobile node is configured to exchange IP flow policy to the
      home agent, then the Flow-Binding extension Section 4.2 reflecting
      the flow policy can be included in the message.  Otherwise, the
      Flow-Binding extension MUST NOT be present in the message.

   o  The mobile node on receiving a Registration Reply with the code
      value set to MULTIPATH_NOT_ALLOWED, MAY choose to register without
      the Multipath extension specified in this document.  This implies
      the home agent has not enabled multipath support for this mobility
      session and hence multipath support must be disabled on the mobile
      node.

   o  The mobile node on receiving a Registration Reply with the code
      value set to INVALID_FB_IDENTIFIER, MUST re-register that specific
      binding for with the home agent.

   o  The mobile node at any time can extend the lifetime of a specific
      care-of address registration by sending a Registration Request to
      the home agent with a new lifetime value.  The message MUST be
      sent as the initial multipath registration and must be routed
      through that specific interface.  The message MUST include the
      Multipath extension Section 4.1 with the value in the Binding-Id
      field set to the binding identifier assigned to that binding.
      Alternatively, the home agent can send a single Registration
      Request with the Bulk Re-registration Flag (B) set to a value of
      (1).  This serves as a request to the home agent to consider this
      request as a request to update the registration lifetime of all
      the mobile node's registrations.

   o  The mobile node at any time can de-register a specific care-of
      address by sending a Registration Request to the home agent with a
      lifetime value of (0).  The message MUST be sent as the initial
      multipath registration and must be routed through that specific
      interface.  The message must include the Multipath extension
      Section 4.1 with the value in the Binding-Id field set to the
      binding identifier assigned to that binding Alternatively, the
      home agent can send a single Registration Request with the Bulk
      Re-registration Flag (B) set to a value of (1) and a lifetime
      value of (0).  This serves as a request to the home agent to
      consider this request as a request to de-register all the mobile
      node's care-of addresses.

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   o  The mobile node at any time can update the parameters of a
      specific registration by sending a Registration Request to the
      home agent.  This includes change of care-of address associated
      with a previously registered interface.  The message must be sent
      as the initial multipath registration and must be routed through
      that specific interface.  The message must include the Multipath
      extension Section 4.1 with the value in the Binding-Id field set
      to the binding identifier assigned to that binding and the
      Overwrite Flag (O) flag MUST set to a value of (1).

   o  The mobile node on receiving a Registration Reply with the code
      value set to 0 (registration accepted), MUST establish a mobile IP
      tunnel to the home agent using that care-of address.  The tunnel
      encapsulation type and any other parameters are based on the
      registration for that path.  If there is also an exchange of flow
      policy between the mobile node and the home agent, with the use of
      Flow-Binding extensions then the mobile node must set up the
      forwarding plane that matches the flow policy.

5.2.  Home Agent Considerations

   The home agent upon receipt of a Registration Request with the
   Multipath extension from a mobile node, should check the
   configuration variable, EnableMultipathSupport.  If the value of this
   variable is set to 0, the home agent MUST reject the request with a
   registration reply and with the code set to MULTIPATH_NOT_ALLOWED.

   The home agent upon receipt of a Registration Request with the
   Multipath extension and with the Bulk Re-registration (B) flag in the
   request set to a value of (1), the home agent upon accepting the
   request MUST extend the lifetime of all the mobile node's bindings.

   The home agent upon receipt of a Registration Request with the Flow-
   Binding Extension must process the extension and upon accepting the
   flow policy must set up the forwarding plane that matches the flow
   policy.  If the home agent cannot identify any of the binding
   identifiers then it MUST reject the request with a Registration Reply
   and with the code set to INVALID_FB_IDENTIFIER.

   The home agent upon receipt of a Registration Request with the
   Multipath extension and if the (O) flag in the request set to a value
   of 1, the home agent upon accepting the request MUST consider this as
   a request to replace all other mobile node's bindings with just one
   binding and that is the binding associated with this request.

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6.  Routing Considerations

   When multipath is enabled for a mobility session, there are
   potentially multiple mobile IP tunnels established between a mobile
   node and its home agent.  These Mobile IP tunnels appear to the
   forwarding plane as equal-cost, point-to-point links.

   If there is also an exchange of flow policy between the mobile node
   and the home agent, with the use of Flow-Binding extensions
   Section 4.2, then the mobile node's IP traffic can be routed by the
   mobility entities as per the negotiated flow policy.  However, if
   multipath is enabled for a mobility session, without the use of any
   flow policy exchange, then both the mobile node and the home agent
   are required to have a pre-configured static flow policy.  The
   specific details on the semantics of this static flow policy is
   outside the scope of this document.

   In the absence of any established traffic flow policies, most IP
   hosts support two alternative traffic load-balancing schemes, Per-
   flow and Per-packet load balancing.  These load balancing schemes
   allow the forwarding plane to evenly distribute traffic based on the
   criteria of either a per-packet or on a per-flow basis, across all
   the available equal-cost links through which a destination can be
   reached.  The default forwarding behavior of Per-flow load balancing
   will ensure a given flow always takes the same path and will
   eliminate any packet re-ordering issues and that is critical for
   delay sensitive traffic.  Whereas the per-destination load balancing
   scheme leverages all the paths much more affectively, but with the
   potential issue of packet re-ordering on the receiver end.  A host
   can choose to enable any of these approaches.  Therefore, this
   specification recommends the use of per-flow load balancing.

7.  Protocol Configuration Variables

   The following protocol configuration variables are required for
   system management and these variables MUST be configurable on all the
   mobility entities.  The configured values for these protocol
   variables MUST survive service restarts.

   EnableMultipathSupport

      This flag indicates whether or not the mobility entity on which
      this protocol variable is configured needs to enable Multipath
      support feature.  This protocol variable is applicable to both the
      home agent and the mobile node.

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      The default value for this flag is set to value of (1), indicating
      that the multipath support is enabled.

      When the value for this flag is set to value of (0), multipath
      support is disabled.

8.  IANA Considerations

   This document requires the following IANA actions.

   o  Action-1: This specification defines a new Mobile IP extension,
      Multipath extension.  It is a non-skippable extension to the
      Mobile IPv4 header in accordance to the short extension format of
      [RFC5944].  The format of this option is described in Section 4.1.
      The type value <IANA-1> for this extension needs to be allocated
      from the registry, "Extensions to Mobile IP Registration
      Messages", at < http://www.iana.org/assignments/mobileip-numbers/
      mobileip-numbers.xhtml>.  RFC Editor: Please replace <IANA-1> in
      Section 4.1 with the assigned value and update this section
      accordingly.

   o  Action-2: This specification defines a new Mobile IP extension,
      Flow-Binding extension.  It is a non-skippable extension to the
      Mobile IPv4 header in accordance to the long extension format of
      [RFC5944].  The format of this option is described in Section 4.2.
      The type value <IANA-2> for this extension needs to be allocated
      from the registry, "Extensions to Mobile IP Registration
      Messages", at < http://www.iana.org/assignments/mobileip-numbers/
      mobileip-numbers.xhtml>.  RFC Editor: Please replace <IANA-2> in
      Section 4.2 with the assigned value and update this section
      accordingly.

   o  Action-3: This document defines new status code value,
      MULTIPATH_NOT_ALLOWED (<IANA-3>), INVALID_FB_IDENTIFIER (<IANA-4>)
      for use by the home agent in the Code field of the Registration
      Reply, as described in Section 4.3.  This value needs to be
      assigned from the "Registration denied by the home agent" registry
      at <http://www.iana.org/assignments/mobility-parameters>.  The
      allocated value has to be greater than 127.  RFC Editor: Please
      replace <IANA-3> in Section 4.3 with the assigned value and update
      this section accordingly.

9.  Security Considerations

   This specification allows a mobile node to establish multiple Mobile
   IP tunnels with its home agent, by registering a care-of address for
   each of its active roaming interfaces.  This essentially allows the
   mobile node's IP traffic to be routed through any of the tunnel paths

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   based on a static or a dynamically negotiated flow policy.  This new
   capability has no impact on the protocol security.  Furthermore, this
   specification defines two new Mobile IP extensions, Multipath
   extension and the Flow-Binding extension.  These extensions are
   specified to be included in Mobile IP control messages, which are
   authenticated and integrity protected as described in [RFC5944].
   Therefore, this specification does not weaken the security of Mobile
   IP Protocol, and does not introduce any new security vulnerabilities.

10.  Contributors

   This document reflects discussions and contributions from the
   following people:

   Ahmad Muhanna

      asmuhanna@yahoo.com

   Srinivasa Kanduru

      skanduru@gmail.com

   Vince Park

      vpark@qualcomm.com

11.  Acknowledgements

   We like to thank Qin Wu, Shahriar Rahman, Mohana Jeyatharan, Yungui
   Wang, Hui Deng Behcet Sarikaya, Jouni Korhonen, Michaela Vanderveen
   and Antti Makela for their review and comments on this draft.

12.  References

12.1.  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.

   [RFC5944]  Perkins, C., "IP Mobility Support for IPv4, Revised",
              RFC 5944, November 2010.

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

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12.2.  Informative References

   [RFC3753]  Manner, J. and M. Kojo, "Mobility Related Terminology",
              RFC 3753, June 2004.

Authors' Addresses

   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

   George Tsirtsis
   Qualcomm

   EMail: tsirtsis@qualcomm.com

   Hesham Soliman
   Elevate Technologies

   EMail: hesham@elevatemobile.com

   Alexandru Petrescu
   CEA LIST
   Communicating Systems Laboratory, Point Courrier 94
   Gif-sur-Yvette  F-91191
   France

   Phone: +33 169089223
   EMail: alexandru.petrescu@cea.fr

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