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Versions: (draft-gundavelli-netext-pmipv6-sipto-option) 00 01 02 03 04 05 06 07 08 09 10 11 12 RFC 6909

NETEXT WG                                             S. Gundavelli, Ed.
Internet-Draft                                                     Cisco
Intended status: Standards Track                                 X. Zhou
Expires: August 16, 2013                                 ZTE Corporation
                                                             J. Korhonen
                                                  Nokia Siemens Networks
                                                                G. Feige
                                                               R. Koodli
                                                                   Cisco
                                                       February 12, 2013


       IPv4 Traffic Offload Selector Option for Proxy Mobile IPv6
              draft-ietf-netext-pmipv6-sipto-option-10.txt

Abstract

   This specification defines a new mobility option, IPv4 Traffic
   Offload Selector option, for Proxy Mobile IPv6.  This option can be
   used by the local mobility anchor and the mobile access gateway for
   negotiating IPv4 traffic offload policy for a mobility session.
   Based on the negotiated IPv4 traffic offload policy, a mobile access
   gateway can selectively offload some of the IPv4 traffic flows in the
   access network instead of tunneling back to the local mobility anchor
   in the home network.

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 August 16, 2013.

Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors.  All rights reserved.




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


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Conventions and Terminology  . . . . . . . . . . . . . . . . .  4
     2.1.  Conventions  . . . . . . . . . . . . . . . . . . . . . . .  4
     2.2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Solution Overview  . . . . . . . . . . . . . . . . . . . . . .  4
     3.1.  IPv4 Traffic Offload Selector Option . . . . . . . . . . .  7
     3.2.  MAG Considerations . . . . . . . . . . . . . . . . . . . .  9
     3.3.  LMA Considerations . . . . . . . . . . . . . . . . . . . . 10
   4.  Protocol Configuration Variables . . . . . . . . . . . . . . . 12
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 12
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 14
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 14
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14






















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1.  Introduction

   Mobile Operators are expanding their network coverage by integrating
   various access technology domains (Ex: Wireless LAN, CDMA, LTE) into
   a common IP mobility core.  The 3GPP S2a Proxy Mobile IPv6 [TS23402]
   reference point, specified by the 3GPP system architecture defines
   the protocol inter-working for building such integrated multi-access
   network.  In this scenario, the mobile node's IP traffic is always
   tunneled back from the mobile access gateway [RFC5213] in the access
   network to the local mobility anchor in the home network.  Currently,
   there is no mechanism for allowing some of the subscriber's IP flows
   to be offloaded in the access network.

   With the exponential growth in the mobile data traffic, mobile
   operators are exploring new ways to offload some of the IP traffic
   flows at the nearest access edge.  The offload is intended either for
   local service access in the access network, or for internet offload
   through the access network when there is an internet peering point.
   Not all IP traffic flows needs to be routed back to the home network,
   some of the non-essential traffic which does not require IP mobility
   support can be offloaded at the mobile access gateway in the access
   network.  This approach allows efficient usage of the mobile packet
   core which helps in lowering transport costs.  The local mobility
   anchor in the home network can deliver the IP flow policy to the
   mobile access gateway in the access network, for identifying the IP
   flows that need to be offloaded.  It's a policy decision as to which
   traffic an operator deems as non-essential.  One operator might
   choose to offload everything except traffic (such as Voice over IP)
   that requires QoS services.  Another might choose to offload only
   HTTP traffic.  From the point of view of this specification, it is
   only about IP traffic matching a given flow selector and
   classification for offload.  This approach has one limitation with
   respect to identifying encrypted traffic: IPsec encrypted traffic
   with no visibility into the application payload cannot be selected
   for offload.

   This document defines a new mobility option, IPv4 Traffic Offload
   Selector option (Section 3.1) for Proxy Mobile IPv6 (PMIPv6).  This
   option can be used by the local mobility anchor for delivering the
   IPv4 traffic offload policy associated with a mobility session to the
   mobile access gateway.  This IPv4 traffic offload policy identifies
   the flow selectors that can used for selecting the flows for
   offloading them at the access edge.  Since, the mobile node's IP
   address topologically belongs to the home network, the offloaded IPv4
   traffic flows may need to be NAT [RFC2663] translated.  These
   offloaded flows will not have mobility support as the NAT becomes the
   anchor point for those flows.  However, when the traffic is offloaded
   for local service access as opposed to internet offload, NAT



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   translation may not be needed, if the mobile access gateways is in
   path for the return traffic.  The decision on when to apply NAT
   translation can be based on local configuration on the mobile access
   gateway.  There are better ways to address the offload problem for
   IPv6 and with the goal not to create NAT66 requirement, this
   specification therefore does not support traffic offload support for
   IPv6 flows.


2.  Conventions and Terminology

2.1.  Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.2.  Terminology

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

   IP Flow

      IP Flow [RFC5101] represents a set of IP packets that match a
      traffic selector.  The selector is typically based on the source
      IP address, destination IP address, source port, destination port
      and other fields in upper layer headers.

   IP Traffic Offload

      The approach of selecting specific IP flows and routing them
      through the access network, instead of tunneling them to the home
      network.  Offload can also be between two access networks
      (Example: moving some of the traffic from LTE access to WLAN
      access).


3.  Solution Overview

   Figure 1 illustrates the scenario where the mobile access gateway in
   an access network has enabled IPv4 traffic offload support for a
   mobility session.  The offload decision is based on the IPv4 traffic
   offload policy that it negotiated with the local mobility anchor in
   the home network.  For example, all the HTTP flows may be offloaded
   at the mobile access gateway and all the other flows for that



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   mobility session are tunneled back to the local mobility anchor.  The
   offloaded flows have to be typically NAT translated and this
   specification does not impose any restrictions on the location of the
   NAT function.  It is possible for the NAT function to be co-located
   with the mobile access gateway or located somewhere in the edge of
   the access network.  When the NAT is not co-located on the mobile
   access gateway, the NAT function should have the ability to identify
   the offloaded IPv4 traffic for NAT policy enforcement.  This could be
   achieved by configuring a specific VLAN between the mobile access
   gateway and the NAT device and ensuring all the traffic on that VLAN
   is NAT translated.  This can also be achieved through other means and
   the details are outside the scope of this document.  It is also to be
   noted that the NAT translation is not required if the offloaded IPv4
   flows are for local service access.

   The traffic selectors in the IPv4 traffic offload policy are used to
   classify the traffic, so it can be offloaded to the access network.
   These parameters include Source IP address, Destination IP address,
   TCP/UDP Port numbers, and other fields.  The format of the IPv4
   Binary Traffic Selector is specified in section 3.1 of [RFC6088].































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                                   _----_
                                 _(      )_
              :-----------------( Internet )---------------:
              |                  (_      _)                |
              |                    '----'                  |
              |                                            |
              :                                            |
   (IPv4 Traffic Offload Point)                            |
              :                                            |
              |                                            |
   ........................................................|....
              |                              |             |
   +--------+ |                   +---------------------+  |
   |  Local | |                   | Services requiring  |  |
   |Services| |                   | mobility, or service|  |
   +--------+ |                   | treatment           |  |
        |     |                   +---------------------+  |
        |   +---+                            |             |
        |   |NAT|                            |             |
        |   +---+                            |             |
        +-----|            _----_            |             |
           +-----+       _(      )_       +-----+          |
   [MN]----| MAG |======(    IP    )======| LMA |----------
           +-----+       (_      _)       +-----+  Internet
                           '----'
                              .
                              .
       [Access Network]       .        [Home Network]
   ..........................................................

             Figure 1: IPv4 Traffic Offload Support at the MAG

   Figure 2 explains the operational sequence of the Proxy Mobile IPv6
   protocol signaling message exchange between the mobile access gateway
   and the local mobility anchor for negotiating the IPv4 Traffic
   Offload selectors.  The details related to DHCP transactions, or
   Router Advertisements on the access link are not shown here as that
   is not the key focus of this specification.  The use of IPv4 Traffic
   Selector option in the Proxy Binding Update is for allowing the MAG
   to request the LMA for the IPv4 Traffic Offload policy.











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   MN    MAG(NAT)   LMA
   |------>|        |    1. Mobile Node Attach
   |       |------->|    2. Proxy Binding Update (IPv4TS)
   |       |<-------|    3. Proxy Binding Acknowledgement (IPv4TS)
   |       |========|    4. Tunnel/Route Setup
   |       +        |    5. Installing the traffic offload rules
   |------>|        |    6. IPv4 packet from mobile node
   |       +        |    7. Offload rule applied (Tunnel/offload)
   |       |        |


           Figure 2: Exchange of IPv4 Traffic Offload Selectors

3.1.  IPv4 Traffic Offload Selector Option

   A new mobility option, IPv4 Traffic Offload Selector option, is
   defined for using it in Proxy Binding Update (PBU) and Proxy Binding
   Acknowledgement (PBA) messages exchanged between a mobile access
   gateway and a local mobility anchor.  This option is used for
   carrying the IPv4 traffic offload policy.  This policy identifies the
   IPv4 traffic flow selectors that can be used by the mobile access
   gateway for enforcing the offload policy.

   The alignment requirement for this option is 4n.


   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      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |M|                         Reserved                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  Traffic Selector Sub-option   ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


              Figure 3: IPv4 Traffic Offload Selector Option

   Type
      <IANA-1>

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






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   Offload Mode (M) Flag
      This field indicates the offload mode.

         If the (M) flag value is set to a value of (0), it is an
         indication that the IPv4 flow(s) matching the traffic selectors
         in the Traffic Selector sub-option [RFC6089] and that are
         associated to that mobility session have to be offloaded at the
         mobile access gateway.  All the other IPv4 flows associated
         with that mobility session and not matching the traffic
         selectors have to be tunneled to the local mobility anchor.

         If the (M) flag value is set to a value of (1), it is an
         indication that all the IPv4 flows associated to that mobility
         session except the IPv4 flow(s) matching the traffic selectors
         in the Traffic Selector sub-option have to be offloaded at the
         mobile access gateway.  All the other IPv4 flows associated
         with that mobility session and not matching the traffic
         selectors have to be tunneled back to the local mobility
         anchor.

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

   Traffic Selector Sub-option
      The traffic selector sub-option includes the parameters used to
      match packets for a specific flow binding.  This is an optional
      sub-option when the IPv4 Traffic Selector option is carried in a
      Proxy Binding Update message, but is a mandatory sub-option when
      the IPv4 Traffic Selector option is carried in a Proxy Binding
      Acknowledgement message.  The format of the Traffic Selector sub-
      option is defined in section 4.2.1.4 of [RFC6089].  This sub-
      option includes a TS Format field, which identifies the format of
      the flow specification included in that sub-option.  The values
      for that field are defined in section 3 of [RFC6088] and are
      repeated here for completeness.  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 that support is
      mandatory for this specification.  The text specified in this
      section takes precedence over what is specified in [RFC6088] and
      [RFC6089].

         1: IPv4 binary traffic selector.

         2: IPv6 binary traffic selector (Not used by this
         specification)





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3.2.  MAG Considerations

   o  If the mobile access gateway is configured to support IPv4 Traffic
      Offload support, then it includes the IPv4 Traffic Offload
      Selector option (Section 3.1) in the Proxy Binding Update message
      that it sends to the local mobility anchor.  Optionally, the
      mobile access gateway can also propose a specific offload policy.

      *  The mobile access gateway MAY choose not to propose any
         specific IPv4 traffic offload policy but request the local
         mobility anchor for the offload policy.  In this scenario, the
         IPv4 Traffic Offload Selector option that is carried in the
         Proxy Binding Update message does not include the Traffic
         Selector sub-option (Section 3.1) and the (M) flag Section 3.1
         in the option MUST be set to value of (0).  Including the IPv4
         Traffic Offload Selector option in the Proxy Binding Update
         without the Traffic Selector Sub-option serves as an indication
         that the mobile access gateway is not proposing any specific
         offload policy for that mobility session, but rather it makes a
         request to the local mobility anchor to provide the offload
         policy.

      *  The mobile access gateway MAY choose to propose a specific IPv4
         traffic offload policy by including the Traffic Selector sub-
         option in the IPv4 Traffic Offload Selector option Section 3.1.
         The specific details on how the mobile access gateway obtains
         the mobile node's IPv4 traffic offload policy, is outside the
         scope of this document.  When this offload policy is included
         in the Proxy Binding Update message, it serves as a proposal to
         the local mobility anchor, which the local mobility anchor can
         override with its own offload policy, or agree to the proposed
         policy.  The offload policy has to be translated to a set of
         selectors that can be used to match the mobile node's IP flows
         and these selectors have to be carried in the Traffic Selector
         Sub-option.  The Traffic Selector sub-option MUST be
         constructed as specified section 4.2.1.4 of [RFC6089].  This
         sub-option includes a Traffic Selector Format field, which
         identifies the format of the flow specification included in
         that sub-option.  The values for that field and the
         corresponding message format are defined in section 3.0 of
         [RFC6088].  Considerations from Section 3.1 apply with respect
         to setting the Offload Mode (M) flag.

   o  When sending a Proxy Binding Update either for Binding lifetime
      extension, or for Binding De-Registration, the mobile access
      gateway SHOULD copy the IPv4 Traffic Offload Selector option from
      the initial Proxy Binding Update message.  Considerations from
      section 6.9.1.3 [RFC5213] and section 6.9.1.4 [RFC5213] MUST be



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      applied.

   o  If the mobile access gateway is not configured to support IPv4
      traffic offload support as specified in this specification, but if
      the received Proxy Binding Acknowledgement message has the IPv4
      Traffic Offload Selector option, then the mobile access gateway
      MUST ignore the option and process the rest of the message as per
      [RFC5213].

   o  If there is no IPv4 Traffic Offload Selector option in the Proxy
      Binding Acknowledgement message received from the local mobility
      anchor, it is indication that the local mobility anchor did not
      enable IPv4 Traffic Offload support for that mobility session.
      The mobile access gateway upon accepting the Proxy Binding
      Acknowledgement message SHOULD NOT enable IPv4 traffic offload
      support for that mobility session.

   o  If there is an IPv4 Traffic Offload Selector option in the Proxy
      Binding Acknowledgement message, then the mobile access gateway
      SHOULD enable the IPv4 traffic offload support for that mobility
      session.  The mobility access gateway has to provision the data
      plane using the flow selectors present in the Traffic Selector
      Sub-option.  The IPv4 flows matching the flow selectors have to be
      offloaded, or tunneled back based to the local mobility anchor
      based on the value of the Offload Mode (M) flag Section 3.1.

3.3.  LMA Considerations

   o  If the received Proxy Binding Update message does not include the
      IPv4 Traffic Offload Selector option (Section 3.1), then the local
      mobility anchor MUST NOT enable IPv4 Traffic Offload support for
      that mobility session and the Proxy Binding Acknowledgement
      message that will be sent in response MUST NOT contain the IPv4
      Traffic Offload Selector option.

   o  If the Proxy Binding Update message includes the IPv4 Traffic
      Offload Selector option, but the local mobility anchor is not
      configured to support IPv4 Traffic Offload support, then the local
      mobility anchor will ignore the option and process the rest of the
      message as per [RFC5213].  This would have no effect on the
      operation of the rest of the protocol.

   o  If the Proxy Binding Update message has the IPv4 Traffic Offload
      Selector option and if the local mobility anchor is configured to
      support IPv4 Traffic Offload support, then the local mobility
      anchor MUST enable IPv4 Traffic Offload support for that mobility
      session.  The Proxy Binding Acknowledgement message that will be
      sent in response MUST include the IPv4 Traffic Offload Selector



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      option.  The following considerations apply with respect to
      constructing the IPv4 Traffic Offload Selector option.

      *  The local mobility anchor can obtain the offload policy from
         the local configuration store, or from a network function such
         as from AAA (Authentication, Authorization and Accounting), or
         PCRF (Policy Charging and Rules Function)).  The offload policy
         has to be translated to a set of selectors that can be used to
         match the mobile node's IP flows and these selectors have to be
         carried in the Traffic Selector Sub-option.  The Traffic
         Selection Sub-option MUST be constructed as specified in
         section 4.2.1.4 of [RFC6089].  Considerations from Section 3.1
         apply with respect to Offload Mode Flag (M) setting.

      *  If the Proxy Binding Update message includes a specific IPv4
         Traffic Offload policy proposal in the form of Traffic Selector
         Sub-option [RFC6089], then the local mobility anchor MAY choose
         to agree to that request by including the same IPv4 Traffic
         Offload policy in the Proxy Binding Acknowledgement message.
         This implies the local mobility anchor has agreed to the mobile
         access gateway provided IPv4 Traffic Offload policy.  The local
         mobility anchor MAY also choose to override the request by
         including a different IPv4 Traffic Offload policy that it wants
         the mobile access gateway to enforce for that mobility session.
         This is entirely based on the policy configuration on the local
         mobility anchor.

      *  The IPv4 traffic offload policy that is sent to the mobile
         access gateway has to be specific to the mobility session
         identified using the Mobile Node Identifier option [RFC5213].
         The offload policy MUST be specific to a mobile node's
         application traffic.  The traffic selectors have to match only
         the mobile node's application traffic and MUST NOT match any
         other mobile node's IP traffic.  Furthermore, control plane
         traffic such as DHCP, ND or any other IP traffic that is used
         for IP address configuration, mobility management or for other
         control plane functions has to be excluded.

      *  The local mobility anchor MUST NOT make any changes to the
         mobile node's offload policy during the middle of a mobility
         session, as that might break some of the IP sessions.
         Therefore the IPv4 Traffic Selector option with the Traffic
         Selector sub-option that is delivered during the initial
         mobility signaling signaling MUST be the same as the one that
         is delivered as part of the mobility signaling related to
         lifetime extension.





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4.  Protocol Configuration Variables

   This specification defines the following configuration variable that
   controls the IPv4 Traffic Offload support feature.  This
   configuration variable is internal to the system and has no bearing
   on interoperability across different implementations.

   The mobility entities, local mobility anchor and the mobile access
   gateway have to allow these variables to be configured by the system
   management.  The configured values for these protocol variables have
   to survive server reboots and service restarts.

   EnableIPv4TrafficOffloadSupport

         This flag indicates whether or not IPv4 Traffic Offload support
         needs to be enabled.  This configuration variable is available
         at both in the mobile access gateway and at the local mobility
         anchor.  The default value for this flag is set to (0),
         indicating that the support for IPv4 Traffic offload support is
         disabled.

         When this flag on the mobile access gateway is set to a value
         of (1), the mobile access gateway has to enable the IPv4
         Traffic offload support for all mobility sessions, specifically
         request the IPv4 traffic offload policy from the local mobility
         anchor by including the IPv4 Traffic Offload Selector option in
         the Proxy Binding Update message.  If the flag is set to a
         value of (0), the mobile access gateway has to disable support
         for IPv4 Traffic Offload support for all mobility sessions.

         Similarly, when this flag on the local mobility anchor is set
         to a value of (1), the local mobility anchor has to enable
         support for IPv4 Traffic offload support.  When the local
         mobility anchor chooses to enable IPv4 Traffic offload support
         and if there is offload policy specified for a mobile node, it
         has to deliver the IPv4 traffic offload policy to the mobile
         access gateway by including the IPv4 Traffic Offload Selector
         option in the Proxy Binding Acknowledgement message.


5.  IANA Considerations

   This document requires the following IANA action.

   o  Action-1: This specification defines a new mobility option, IPv4
      Traffic Offload Selector option.  This option is described in
      Section 3.1.  The Type value for this option needs to be assigned
      from the same numbering space as allocated for the other mobility



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      options [RFC6275].

   o  RFC Editor: Please replace <IANA-1> in Section 4 with the assigned
      value, and update this section accordingly.


6.  Security Considerations

   The IPv4 Traffic Offload Selector option defined in this
   specification is for use in Proxy Binding Update and Proxy Binding
   Acknowledgement messages.  This option is carried like any other
   mobility header option as specified in [RFC5213].  Therefore it
   inherits from [RFC5213] its security guidelines and does not require
   any additional security considerations.  Carrying IPv4 traffic
   offload selectors does not introduce any new security
   vulnerabilities.

   When IPv4 traffic offload support is enabled for a mobile node, the
   mobile access gateway selectively offloads some of the mobile node's
   IPv4 traffic flows to the access network.  Typically, these offloaded
   flows get NAT translated and essentially that introduces certain
   vulnerabilities which are common to any NAT deployment.  These
   vulnerabilities and the related considerations have been well
   documented in the NAT specification [RFC2663].  There are no
   additional considerations above and beyond what has already been
   documented by the NAT specifications and which are unique to the
   approach specified in this document.

   The mobile node's home network may be equipped with firewall and
   other security devices to guard against any security threats.  When
   IPv4 traffic offload support is enabled, it potentially exposes the
   mobile node to some security risks in the access network.  This
   threat can be mitigated by deploying the security features in the
   access network as in the home network.

   When IPv4 traffic offload support is enabled for a mobile node, some
   of the IP flows are sent through the home network and some other IP
   flows are routed through the access network.  This potentially
   introduces some complexity with respect to enabling diagnostics or
   monitoring on the user traffic.  The tools that are used for such
   diagnostics have to be aware of the offload policy that in enabled in
   the network.


7.  Acknowledgements

   The authors would like to thank Ahmad Muhanna, Basavaraj Patil,
   Carlos Bernardos, Eric Voit, Frank Brockners, Hidetoshi Yokota, Marco



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   Liebsch, Mark Grayson, Pierrick Seite, Ryuji Wakikawa, Steve Wood,
   Barry Lieba, Sean Turner, Pete Resnick, Wesley Eddy, Mary Barnes,
   Vincent Roca, Ralph Droms, Scott Bradner, Stephen Farrell, Adrian
   Farrell, Benoit Claise and Brian Haberman for all the draft reviews
   and discussions related to the topic of IPv4 traffic offload.


8.  References

8.1.  Normative References

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

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

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

   [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.

8.2.  Informative References

   [RFC2663]  Srisuresh, P. and M. Holdrege, "IP Network Address
              Translator (NAT) Terminology and Considerations",
              RFC 2663, August 1999.

   [RFC5101]  Claise, B., "Specification of the IP Flow Information
              Export (IPFIX) Protocol for the Exchange of IP Traffic
              Flow Information", RFC 5101, January 2008.

   [TS23402]  3GPP, "Architecture enhancements for non-3GPP accesses",
              2010.







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Authors' Addresses

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

   Email: sgundave@cisco.com


   Xingyue Zhou
   ZTE Corporation
   No.68 Zijinghua Rd
   Nanjing
   China

   Email: zhou.xingyue@zte.com.cn


   Jouni Korhonen
   Nokia Siemens Networks
   Linnoitustie 6
   Espoo  FIN-02600
   Finland

   Email: jouni.nospam@gmail.com


   Gaetan
   Cisco
   France

   Email: gfeige@cisco.com


   Rajeev Koodli
   Cisco
   3650 Cisco Way
   San Jose, CA  95134
   USA

   Email: rkoodli@cisco.com








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