DMM WG                                                          P. Seite
Internet-Draft                                                    Orange
Intended status: Standards Track                                A. Yegin
Expires: April 30, 2015                                          Samsung
                                                           S. Gundavelli
                                                                   Cisco
                                                        October 27, 2014


              Multihoming support for Residential Gateways
                 draft-seite-dmm-rg-multihoming-00.txt

Abstract

   The Quality-of-Experience of a fixed-network user can be
   significantly improved by enabling the Residential Gateway (RG)
   providing IP connectivity services to connect to the internet through
   multiple access networks (Example: LTE and DSL) and use all the
   available network bandwidth for the user traffic.  This approach
   enables a service provider to leverage all the availble access
   networks and to offer guaranteed Quality-of-Service to the end-user
   on any application basis.  Furthermore, the mobility functions in the
   residential gateway and in the service provider network will be able
   to monitor the performance of all the access paths and dynamically
   change the routing path for an application.  This document
   investigates the use of IP mobility protocols for supporting this
   use-case and it also identifies the needed protocol extensions.
   However, those extensions will be specified in a companion document.

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 April 30, 2015.

Copyright Notice




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   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Conventions and Terminology  . . . . . . . . . . . . . . . . .  4
     2.1.  Conventions  . . . . . . . . . . . . . . . . . . . . . . .  4
     2.2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Use-cases  . . . . . . . . . . . . . . . . . . . . . . . . . .  5
   4.  Architectures and requirements . . . . . . . . . . . . . . . .  5
     4.1.  Architectures  . . . . . . . . . . . . . . . . . . . . . .  5
     4.2.  Traffic distribution schemes . . . . . . . . . . . . . . .  8
     4.3.  Tunnelling . . . . . . . . . . . . . . . . . . . . . . . .  9
   5.  Solution Overview - PMIPv6 Approach  . . . . . . . . . . . . .  9
     5.1.  Protocol Extensions  . . . . . . . . . . . . . . . . . . . 10
       5.1.1.  MAG Multipath-Binding Option . . . . . . . . . . . . . 10
       5.1.2.  MAG Identifier Option  . . . . . . . . . . . . . . . . 11
       5.1.3.  New Status Code for Proxy Binding Acknowledgement  . . 12
     5.2.  Call Flows . . . . . . . . . . . . . . . . . . . . . . . . 12
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 13
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 14
   8.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 15
     9.2.  Informative References . . . . . . . . . . . . . . . . . . 15
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16













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1.  Introduction

   Fixed access networks (e.g.  DSL) usually provides Internet
   connectivity via a Residential Gateway (RG) acting as the access
   router.  When equipped with different Wide Area Network (WAN) access
   technologies (e.g.  DSL and LTE), the RG could take benefit of
   multihoming advantages such as redundancy, load balancing, load
   sharing and so on.  Besides, the Broadband Forum (BBF) has recently
   initiated a new standardization effort, "Hybrid Access for Broadband
   Networks" [WT-348] to address this use-case.  The multihomed RG use-
   case has been identified as an IP mobility scenario for a while
   [RFC4908].  In a fix network context, like in the "Hybrid Access for
   Broadband Networks" scenario, IP mobility protocols are obviously not
   used to manage user mobility, but for their subscriber and traffic
   management capabilities (e.g. move IP traffic between WAN interfaces
   while maintaining IP session continuity).  Moreover, the hybrid
   access system can take benefit from the policy routing (i.e.  IP flow
   routing policies) capability of the IP mobility protocols.

   This document refreshes [RFC4908] by describing how to use the IP
   mobility protocols (e.g.  [RFC3753], [RFC6275] and [RFC5213]) and
   their extensions (e.g.  Multiple care-of-address [RFC5648], IP flow
   mobility [RFC6089])to address the Hybrid Access issue.  The usual IP
   mobility protocols operations allows sharing WAN interfaces on an IP
   flow basis: a multihomed RG uses simultaneously more that one WAN
   interface (e.g.  DSL and LTE) and each IP flow is bounded to one of
   the available interfaces, as per IP flow mobility use-case [RFC6089].
   "Hybrid access" use-case is also expected to operate on a IP packet
   basis: packets of a single IP flow are distributed over more than one
   WAN interface, i.e. the system performs WAN interfaces bonding to
   provide higher WAN bandwidth to a single IP flow.  Although interface
   bonding differs from the usual IP mobility operations, this document
   addresses this use-case as well.  Actually, IP mobility protocols
   allow to establish and maintain the forwarding plane in user, of
   flow, mobility situation (i.e. using IP tunnels); but nothing prevent
   to use this data plane on a per packet basis.  It must be noted that
   this traffic distribution scheme may raise tricky packet reordering
   and buffering issues.  However, addressing these issues is out the
   scope of this document.  At last, this document identifies new
   mobility options that would be necessary to address some of the
   hybrid access use-case.  These extensions will be defined in a
   companion document.

   Document requires additional updates and efforts are in progress.







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     Flow-1
      |
      |Flow-2              _----_
      | |         CoA-1  _(      )_   Tunnel-1
      | |    .---=======(   LTE    )========\ Flow-1
      | |    |           (_      _)          \Flow-4
      | |    |             '----'             \
      | | +=====+                              \  +=====+    _----_
      | '-|     |                               \ |     |  _(      )_
      '---| CPE |                                 | BNG |-( Internet )--
      .---|     |                                 |     |  (_      _)
      | .-|     |                               / |     |    '----'
      | | +=====+                              /  +=====+
      | |    |             _----_             /
      | |    |    CoA-2  _(      )_ Tunnel-2 /
      | |    .---=======(   DSL    )========/ Flow-2
      | |                (_     _)           Flow-3
      | |                  '----'
      |Flow-3
      |
     Flow0=-4



                    Figure 1: Hybrid-Access With PMIPv6


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 mobility related terms used in this document are to be
   interpreted as defined in [RFC5213], [RFC5844] and [RFC7148].
   Additionally, this document uses the following terms:

   IP-in-IP

      IP-within-IP encapsulation [RFC2473], [RFC4213]







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3.  Use-cases

   The current evolution of the Internet usage makes users more and more
   greedy of high throughput services (e.g. video streaming, file
   downloading, peer-to-peer,....).  However, upgrading the fix access,
   to meet resulting high bandwidth demand, is sometimes difficult; for
   example in historic cities downtown where only Internet access based
   on old copper line is deployed.  At the same time, these areas may be
   within LTE coverage from which the user could benefit to access the
   Internet services.  In this situation "Hybrid access for Broadband
   Networks" system, using a multiple WAN interfaces RG, may come into
   play with the two following use-cases:

      Load balancing: the hybrid access system uses simultaneously all
      the available WAN interfaces and binds each application on one of
      these interface, i.e. increase WAN bandwidth from the user
      standpoint.  The system must be able to identify traffic (e.g.
      issued from a specific user, or terminal; or an application) and,
      depending on its characteristics (e.g.  QoS requirements),
      forwards it on the most appropriate WAN interface.

      Load sharing: The hybrid access allows the user to get access to
      higher throughput services (e.g.  IPTV).  The RG is equipped with
      and combines them to get additional WAN resources and provide
      higher bandwidth per application.


4.  Architectures and requirements

4.1.  Architectures

   Figure 2 depicts the architecture for hybrid access use-cases relying
   on multiple WAN interfaces Residential Gateway.  WAN interfaces can
   be either physical (e.g.  DSL, LTE) or virtual (e.g.  VLAN).  On the
   network side, an aggregation gateway is in charge to distribute the
   downlink traffic to the different WAN paths.  Uplink traffic
   management depends on the traffic distribution scheme (see
   Section 4.2); it is detailed in section .  In this architecture, the
   RG can be viewed as a mobile router, or mobile node, (so, supporting
   mobility management client) managing multiple local interfaces, i.e.
   multiple care-of-addresses.  IP mobility protocols (Mobile IPv6
   [RFC6275]) or NEMO [RFC3963]), together with Multiple Care-of-Address
   [RFC5648]), can thus be used to establish dynamically the forwarding
   paths between the RG and the IP the aggregation gateway, so playing a
   mobility anchor role.

   The RG obtains local IP addresses, i.e. care-of-address, via legacy
   IP allocation mechanisms (e.g.  DHCP, SLAAC) of the WAN interfaces.



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   Then, in order to set-up data path up to the aggregation gateway
   (i.e. mobility anchor), the RG uses the multiple care-of-addresses
   [RFC5648] mobility option to registers these care-of-addresses to the
   mobility anchor.  Registration is managed using NEMO [RFC3963]) or
   Mobile IPv6 [RFC6275] protocols.  Bi-directional IP tunnels are
   established, between the RG and the mobility anchor, over each WAN
   interface.  The mobility anchor provision the RG with a unique IP
   address, i.e.  Home Prefix/Address, through which the RG is reachable
   from then Internet.  When the Home Agent receives a data packet meant
   for a node in the RG Network, it tunnels the packet to the RG to one
   of the available care-of address.  The selection of the care-of-
   address depends on the traffic distribution scheme, operating either
   on a IP flow or on packet basis (see Section 4.2).


                         IP Network #1
                          (e.g. DSL)
    +------------+        _--------_    +------------+
    |            |       (          )   |            |
    |Residential +======(==IP-in-IP==)==+            |
    | Gateway    |       (_        _)   |Aggregation |
    |  (RG)      |         (_______)    | Gateway    |
    |            |                      |(Home Agent)|------>
    |  Mobility  |                      |            |
    |  Client    |                      |            |
    |            |        _--------_    |            |
    |            |       (          )   |            |
    |            +======(==IP-in-IP==)==+            |
    |            |       (_        _)   |            |
    +-----+------+         (______)     +------------+
          |             IP Network #2
   ----RG network----     (eg. LTE)
          |
       end-nodes



                   Figure 2: Multihomed RG architecture

   Some deployment architecture, the hybrid access management is not
   supported by the RG.  For example, in Figure 3, DSL and LTE networks
   are operated by two different operators and the hybrid access service
   is provided by the mobile operator.








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                          DSL access
    +------------+        _--------_    +------------+
    |            |       (          )   |            |
    |Residential +======(==IP-in-IP==)==+            |
    | Gateway    |       (_        _)   |Aggregation |
    +------------+         (_______)    | Gateway    |
          |                             |(Home Agent)|------>
         WLAN (RG network)              |            |
          |                LTE Access   |            |
    +------------+        _--------_    |            |
    |            |       (          )   |            |
    |  Mobility  +======(==IP-in-IP==)==+            |
    |   Client   |       (_        _)   |            |
    +-----+------+         (______)     +------------+
          |
      Hybrid access network
          |
       end-nodes

              Figure 3: split RG and hybrid access management

   Proxy Mobile IPv6 [RFC5648] can be used to provide IP session
   continuity when a mobile node moves between the cellular network to
   the home network between RG, or between access router (e.g.  RG).  In
   Proxy Mobile IPv6 architecture, the access router supporting mobility
   management functions is called a Mobile Access Gateway (MAG).  Being
   functionally similar to the RG, the MAG could take benefit from the
   hybrid access advantages.  To do so, the MAG must be to manage
   multiple care-of-addresses as depicted in Figure 4.

                                        +------------+
    +------------+                      |            |
    |            +==PMIP Tunnel / DSL===+            |
    |  MAG #1    |                      |            |
    |            +==PMIP tunnel / LTE===+            |
    +------------+                      |    LMA     |
        |                               |            |
    MN#2|          --------             |            |------>
        |   MN#1-(   LTE    )===========|            |
        |     |  (          )           |            |
        V     V    --------             |            |
    +------------+                      |            |
    |            +==PMIP Tunnel / DSL===+            |
    |   MAG #2   |                      |            |
    |            +==PMIP tunnel / LTE===+            |
    +------------+                      +------------+

                     Figure 4: Multihomed MAG for PMIP



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4.2.  Traffic distribution schemes

   IP mobility protocols allow to establish the forwarding plane over
   the WAN interfaces of a multihomed RG.  Then, traffic distribution
   schemes define the way to distribute data packets over these paths
   (i.e.  IP tunnels).  Traffic distribution can be managed either on a
   per-flow or on a per-packet basis:

   o  per-flow traffic management: each IP flow (both upstream and
      downstream) is mapped to a given mobile IP tunnel, corresponding
      to a given WAN interface.  This scenario is based on IP flow
      mobility mechanism using the Flow binding extension [RFC6089].
      The mobility anchor provides IP session continuity when an IP flow
      is moved from one WAN interfaces to another.  The flow binding
      extension allows the IP mobility anchor and the RG to exchange,
      and synchronize, IP flow management policies (i.e. policy routing
      rules associating traffic selectors [RFC6088] to mobility
      bindings).

   o  Per-packet management: distribute the IP packets of a same IP
      flow, or of a group of IP flows, over more than one WAN interface.
      In this scenario, traffic management slightly differs from the
      default mobile IP behaviour; the mobility entities (mobility ancho
      and client) distribute packets, belonging to a same IP flow, over
      more than one bindings simultaneously.  The definition of control
      algorithm of a Per-packet distribution scheme (how to distribute
      packets) is out the scope of this document.  When operating at the
      packet level, traffic distribution scheme may introduce packet
      latency and out-of-order delivery; it thus requires to introduce
      buffering and reordering capabilities in both aggregation entities
      (RG and mobility anchor).  In this situation, using the GRE as
      mobile tunnelling mechanism together with the GRE KEY option
      [RFC5845] allows adding sequence number to GRE packets.  This
      sequence number can be used to reorder data traffic packets.  More
      detailed buffering and reordering considerations are out of the
      scope of this document.

   The traffic distribution scheme may require the RG and the to
   exchange interface metrics to make traffic steering decision.For
   example, the RG may sent its DSL synchronization rate to the mobility
   anchor, so that the latter can make traffic forwarding decision
   accordingly.  In this case, the vendor specific mobility option
   [RFC5094] can be used for that purpose.

   Per-flow and per-packet distribution schemes are not exclusive
   mechanisms; they can cohabit in the same hybrid access system.  For
   example, High throughput services (e.g. video streaming) may benefit
   from per-packet distribution scheme, while some other may not.



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   Typically VoIP application are sensitive to latency and thus should
   not be split over different WAN paths.  In this situation, the
   aggregation entities (RG and mobility anchor) must exchange traffic
   management policies to associate distribution scheme, traffic and WAN
   interface (physical or virtual).  [RFC6088] and [RFC6089] define
   traffic management on a flow basis but there is no such policy on a
   per packet basis.

4.3.  Tunnelling

   The hybrid access system should be able to support multiple type of
   tunnelling mechanisms:

   o  IP-in-IP: default IP mobility tunnelling mechanism.

   o  GRE: the GRE KEY option can allow to manage packet reordering

   o  GTP: Network based mobility management of the 3GPP cellular
      networks use GTP as tunnelling mechanism.

   o  IPsec


5.  Solution Overview - PMIPv6 Approach

   The MAG functionality is enabled on the CPE and the LMA functionality
   is enabled on the agregation gateway inside the SP network.



                           _----_
                  CoA-1  _(      )_   Tunnel-1
             .---=======(   LTE    )========\ Flow-1
             |           (_      _)          \Flow-4
             |             '----'             \
          +=====+                              \  +=====+    _----_
          |     |                               \ |     |  _(      )_
          | MAG |                                 | LMA |-( Internet )--
      .---|     |                                 |     |  (_      _)
      |   |(CPE)|                               / |     |    '----'
      |   +=====+                              /  +=====+
      |      |             _----_             /
      |      |    CoA-2  _(      )_ Tunnel-2 /
      |      .---=======(  Fixed   )========/ Flow-2
      |                  (_      _)           Flow-3
      |                    '----'
      |
     [MN]



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                    Figure 5: Hybrid-Access With PMIPv6

5.1.  Protocol Extensions

5.1.1.  MAG Multipath-Binding Option

   The MAG Multipath-Binding option is a new mobility header option
   defined for use with Proxy Binding Update and Proxy Binding
   Acknowledgement messages exchanged between the local mobility anchor
   and the mobile access gateway.

   This mobility header option is used for requesting multipath support.
   It indicates that the mobile access gateway is requesting the local
   mobility anchor to register the current care-of address associated
   with the request as one of the many care-addresses through which the
   mobile access gateway can be reached.  It is also for carrying the
   information related to the access network associated with the care-of
   address.

   The MAG Multipath-Binding option has an alignment requirement of
   8n+2.  Its format is as shown in Figure 6:

   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      Type     |   Length      |    If-ATT     |    If-Label   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Binding-Id   |B|O|             RESERVED                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 6: MAG Multipath Binding Option

   Type

      <IANA-1> To be assigned by IANA.

   Length

      8-bit unsigned integer indicating the length of the option in
      octets, excluding the type and length fields.

   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].

   This 8-bit field represents the interface label represented as an
   unsigned integer.  The mobile node identifies the label for each of



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   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.

   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
   access gateway assigns a unique value for each of its interfaces and
   includes them in the message.

   This flag, if set to a value of (1), is to notify the local mobility
   anchor 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).

   This flag, if set to a value of (1), notifies the local mobility
   anchor 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.

   Reserved

      This field is unused in this specification.  The value MUST be set
      to zero (0) by the sender and MUST be ignored by the receiver.

5.1.2.  MAG Identifier Option

   The MAG Identifier option is a

   This option does not have any alignment requirements.







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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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      Type     |   Length      |  Subtype      |  Reserved     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           Identifier ...                      ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                      Figure 7: MAG Identifier Option

   Type

      <IANA-2> To be assigned by IANA.

   Length

      8-bit unsigned integer indicating the length of the option in
      octets, excluding the type and length fields.

   Subtype

      One byte unsigned integer used for identifying the type of the
      Identifier field.  Accepted values for this field are the
      registered type values from the Mobile Node Identifier Option
      Subtypes registry.

   Reserved

      This field is unused in this specification.  The value MUST be set
      to zero (0) by the sender and MUST be ignored by the receiver.

   Identifier

      A variable length identifier of type indicated in the Subtype
      field.

5.1.3.  New Status Code for Proxy Binding Acknowledgement

   This document defines the following new Status Code value for use in
   Proxy Binding Acknowledgement message.

   CANNOT_SUPPORT_MULTIPATH_BINDING (Cannot Support Multipath Binding):
   <IANA-4>

5.2.  Call Flows

   Figure 8 is the callflow detailing hybrid access support with PMIPv6.
   The CPE in this example scenario is equipped with both WLAN and LTE



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   interfaces and is also configured with the MAG functionality.  A
   logical-NAI with ALWAYS-ON configuration is enabled on the MAG.  The
   mobility session that is created on the LMA is for the logical-NAI.
   The IP hosts MN_1 and MN_2 are assigned IP addresses from the
   delegated mobile network prefix.



   +=====+ +=====+        +=====+      +=====+      +=====+      +=====+
   | MN_1| | MN_2|        | MAG |      | WLAN|      | LTE |      | LMA |
   +=====+ +=====+        +=====+      +=====+      +=====+      +=====+
      |       |              |            |            |            |
      |       |              |            |            |            |
      |       |              | (1) ATTACH |            |            |
      |       |              | <--------> |            |            |
      |       |              | (2) ATTACH              |            |
      |       |              | <---------------------->|            |
      |       |              | (3) PBU (NAI, MAG-NAI, DMNP, MMB)    |
      |       |              | ------------------------*----------> |
      |       |              | (4) PBA (NAI, DMNP)                  |
      |       |              | <-----------------------*----------- |
      |       |              | (5) TUNNEL INTERFACE CREATION        |
      |       |              |-============== TUNNEL ==*===========-|
      |       |              |                                      |
      |       |              | (6) PBU (NAI, MAG-NAI, DMNP, MMB)    |
      |       |              | -----------*-----------------------> |
      |       |              | (7) PBA (NAI, DMNP)                  |
      |       |              | <----------*------------------------ |
      |       |              | (8) TUNNEL INTERFACE CREATION        |
      |       |              |-===========*== TUNNEL ==============-|
      |   (9)                |                                      |
      | <------------------> |                                      |
      |       |  (10)        |                                      |
      |       |<-----------> |                                      |


       Figure 8: Functional Separation of the Control and User Plane


6.  IANA Considerations

   This document requires the following IANA actions.

   o  Action-1: This specification defines a new mobility option, the
      MAG Multipath-Binding option.  The format of this option is
      described in Section 5.1.1.  The type value <IANA-1> for this
      mobility option needs to be allocated from the Mobility Options
      registry at <http://www.iana.org/assignments/mobility-parameters>.



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      RFC Editor: Please replace <IANA-1> in Section 5.1.1 with the
      assigned value and update this section accordingly.

   o  Action-2: This specification defines a new mobility option, the
      MAG Identifier option.  The format of this option is described in
      Section 5.1.2.  The type value <IANA-2> for this mobility option
      needs to be allocated from the Mobility Options registry at
      <http://www.iana.org/assignments/mobility-parameters>.  RFC
      Editor: Please replace <IANA-2> in Section 5.1.2 with the assigned
      value and update this section accordingly.

   o  Action-4: This document defines a new status value,
      CANNOT_SUPPORT_MULTIPATH_BINDING (<IANA-4>) for use in Proxy
      Binding Acknowledgement message, as described in Section 5.1.3.
      This value is to be assigned from the "Status Codes" registry at
      <http://www.iana.org/assignments/mobility-parameters>.  The
      allocated value has to be greater than 127.  RFC Editor: Please
      replace <IANA-4> in Section 5.1.3 with the assigned value and
      update this section accordingly.


7.  Security Considerations

   This specification allows a mobile access gateway to establish
   multiple Proxy Mobile IPv6 tunnels with a local mobility anchor, by
   registering a care-of address for each of its connected access
   networks.  This essentially allows the mobile node's IP traffic to be
   routed through any of the tunnel paths and either 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 mobility header options, MAG Multipath-Binding option
   and the MAG Identifier option.  These options are carried like any
   other mobility header option as specified in [RFC5213].  Therefore,
   it inherits security guidelines from [RFC5213].  Thus, this
   specification does not weaken the security of Proxy Mobile IPv6
   Protocol, and does not introduce any new security vulnerabilities.


8.  Acknowledgements

   The authors of this draft would like to acknowledge the discussions
   and feedback on this topic from the members of the Broadband Forum.


9.  References






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9.1.  Normative References

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

   [RFC3963]  Devarapalli, V., Wakikawa, R., Petrescu, A., and P.
              Thubert, "Network Mobility (NEMO) Basic Support Protocol",
              RFC 3963, January 2005.

   [RFC5094]  Devarapalli, V., Patel, A., and K. Leung, "Mobile IPv6
              Vendor Specific Option", RFC 5094, December 2007.

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

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

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

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

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

   [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.

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

   [RFC7148]  Zhou, X., Korhonen, J., Williams, C., Gundavelli, S., and
              CJ. Bernardos, "Prefix Delegation Support for Proxy Mobile
              IPv6", RFC 7148, March 2014.

9.2.  Informative References

   [RFC2473]  Conta, A. and S. Deering, "Generic Packet Tunneling in
              IPv6 Specification", RFC 2473, December 1998.

   [RFC3753]  Manner, J. and M. Kojo, "Mobility Related Terminology",



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              RFC 3753, June 2004.

   [RFC4213]  Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms
              for IPv6 Hosts and Routers", RFC 4213, October 2005.

   [RFC4908]  Nagami, K., Uda, S., Ogashiwa, N., Esaki, H., Wakikawa,
              R., and H. Ohnishi, "Multi-homing for small scale fixed
              network Using Mobile IP and NEMO", RFC 4908, June 2007.

   [WT-348]   "Liaison Statement: Broadband Forum Work on "Hybrid Access
              for Broadband Networks" (WT-348)", BBF Broadband Forum,
              October 2014, <http://datatracker.ietf.org/liaison/1355/>.


Authors' Addresses

   Pierrick Seite
   Orange
   4, rue du Clos Courtel, BP 91226
   Cesson-Sevigne  35512
   France

   Email: pierrick.seite@orange.com


   Alper Yegin
   Samsung
   Istanbul
   Turkey

   Email: alper.yegin@partner.samsung.com


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

   Email: sgundave@cisco.com











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