[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-gundavelli-netext-pmipv6-sipto-option) 00 01 02 03 04 RFC 6909

NETEXT WG                                             S. Gundavelli, Ed.
Internet-Draft                                                     Cisco
Intended status: Standards Track                                 X. Zhou
Expires: August 3, 2012                                  ZTE Corporation
                                                             J. Korhonen
                                                  Nokia Siemens Networks
                                                                G. Feige
                                                               R. Koodli
                                                                   Cisco
                                                        January 31, 2012


       IPv4 Traffic Offload Selector Option for Proxy Mobile IPv6
              draft-ietf-netext-pmipv6-sipto-option-02.txt

Abstract

   This specification defines a mechanism and a related mobility option
   for carrying IPv4 Offload traffic selectors between a mobile access
   gateway and a local mobility anchor in a Proxy Mobile IPv6 domain.
   Based on the received offload flow selectors from the local mobility
   anchor, a mobile access gateway can enable offload traffic rule on
   the selected IPv4 flows.

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 3, 2012.

Copyright Notice

   Copyright (c) 2012 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



Gundavelli, et al.       Expires August 3, 2012                 [Page 1]

Internet-Draft    IPv4 Traffic Offload Selector Option      January 2012


   (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  . . . . . . . . . . . . . . . . .  3
     2.1.  Conventions  . . . . . . . . . . . . . . . . . . . . . . .  4
     2.2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Solution Overview  . . . . . . . . . . . . . . . . . . . . . .  4
     3.1.  LMA Considerations . . . . . . . . . . . . . . . . . . . .  6
     3.2.  MAG Considerations . . . . . . . . . . . . . . . . . . . .  6
   4.  IP Traffic Offload Selector Option . . . . . . . . . . . . . .  7
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  8
   6.  Protocol Configuration Variables . . . . . . . . . . . . . . .  9
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 10
   8.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 10
     9.2.  Informative References . . . . . . . . . . . . . . . . . . 11
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11
























Gundavelli, et al.       Expires August 3, 2012                 [Page 2]

Internet-Draft    IPv4 Traffic Offload Selector Option      January 2012


1.  Introduction

   Mobile Operators are expanding their network coverage by integrating
   various access technology domains into a common IP mobile core.  For
   providing IP mobility support to a mobile node irrespective of the
   access network to which it is attached, the 3GPP S2a Proxy Mobile
   IPv6 [TS23402] interface, specified by the 3GPP system architecture,
   is providing the needed protocol glue.  When this protocol interface
   based on Proxy Mobile IPv6 [RFC5213] is used, the mobile node is
   topologically anchored at the local mobility anchor [RFC5213] in the
   home network.  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.

   However, 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 where ever there is an
   internet peering point, as supposed to carrying it all the way to the
   mobility anchor in the home network.  Not all IP traffic 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 provides
   greater leverage and efficient usage of the mobile packet core which
   help lowering transport cost.  The local mobility anchor in the home
   network can potentially deliver the IP flow selectors to the mobile
   access gateway in the access network, for identifying the IP flows
   that needs to be offloaded.

   This document defines a new mobility option, IP Traffic Offload
   Selector option for Proxy Mobile IPv6 (PMIPv6).  This option can be
   used by the local mobility anchor to notify the mobile access gateway
   with 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 IP
   traffic flows need to be NAT [RFC2663] translated.  Given this NAT
   translation requirement for the offloaded traffic, this approach will
   be limited to mobile node's IPv4 flows.  There are better ways to
   solve this problem for IPv6 and with the goal not to create NAT66
   requirement, this specification does not support traffic offload
   support for IPv6 flows.  This document also does not define any new
   semantics for flow selectors.  The flow identification and the
   related semantics are all leveraged from [RFC6088].


2.  Conventions and Terminology






Gundavelli, et al.       Expires August 3, 2012                 [Page 3]

Internet-Draft    IPv4 Traffic Offload Selector Option      January 2012


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 abbreviations:

   IP Flow

      IP Flow 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.

   Selective IP Traffic Offload (SIPTO)

      The approach of selecting specific IP flows and routing them to
      the local network, as supposed to tunneling them to the home
      network.

   NAT (Network Address Translation)

      Network Address Translation [RFC2663] is a method by which IP
      addresses are mapped from one address realm to another, providing
      transparent routing to end hosts.


3.  Solution Overview

   The following illustrates the scenario where the mobile access
   gateway in an access network having the ability to offload some of
   the IPv4 traffic flows, based on the traffic selectors it received
   from the local mobility anchor in the home network.  For example, all
   the HTTP flows may be be offloaded at the mobile access gateway and
   all the other flows for that mobility session are tunneled back to
   the local mobility anchor.

   The selectors that are delivered to the mobile access gateway can be
   used to classify the traffic, so it can be offloaded to the local
   access network.  The parameters in the IP traffic selectors can be
   used to match against the fields in the IP packet header.  These
   parameters include Source IP address, Destination IP address, TCP/UDP



Gundavelli, et al.       Expires August 3, 2012                 [Page 4]

Internet-Draft    IPv4 Traffic Offload Selector Option      January 2012


   Port numbers, and other fields.

            _----_
          _(      )_
         ( Internet )
          (_      _)
            '----'
              |
   (IPv4 Traffic Offload Point
    at access edge gateway for
    non-essential traffic
    Ex: HTTP Traffic Offloaded)
              |
   ......................................................
              |               .        +----------------+
            +---+             .        | Operator Value |
            |NAT|             .        | Added Services |
            +---+             .        +----------------+
              |            _----_             |
           +-----+       _(      )_       +-----+
   [MN]----| MAG |======(    IP    )======| LMA |-- Internet
           +-----+       (_      _)       +-----+
                           '----'      (
                              .
                              .
                              .
       [Access Network]       .        [Home Network]
   ......................................................

                 Figure 1: Access Networks attached to MAG

   Figure 1 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 IP Traffic Offload
   selectors.


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





Gundavelli, et al.       Expires August 3, 2012                 [Page 5]

Internet-Draft    IPv4 Traffic Offload Selector Option      January 2012


            Figure 2: Exchange of IP Traffic Offload Selectors

3.1.  LMA Considerations

   The following considerations apply to the local mobility anchor.

   o  If the received Proxy Binding Update includes the IP Traffic
      Offload Selector Option Section 4, but if the configuration
      variable, EnableIPTrafficOffloadSupport on the local mobility
      anchor is set to a value of (0), then the local mobility anchor
      MUST ignore the IP Traffic Offload Selector Option and process the
      rest of the packet.  This would not have no effect on the
      operation of the rest of the protocol.

   o  If the received Proxy Binding Update includes the IP Traffic
      Offload Selector Option Section 4, and if the configuration
      variable, EnableIPTrafficOffloadSupport on the local mobility
      anchor is set to a value of (1), then the local mobility anchor
      can acquire the offload policy from a network function (Ex: AAA or
      PCRF) and can construct the traffic selectors based on the offload
      policy and deliver those selectors in the Proxy Binding
      Acknowledgement message using the IP Traffic Offload Selector
      Option.  However, if the received Proxy Binding Update included a
      proposed Offload traffic selectors, the local mobility anchor MAY
      choose to honor that request and include the proposed selectors in
      the reply.

3.2.  MAG Considerations

   o  If the configuration variable, EnableIPTrafficOffloadSupport on
      the mobile access gateway is set to a value of (0), then the
      mobile access gateway MUST NOT include the IP Traffic Offload
      Selector Option Section 4 in the Proxy Binding Update message that
      it sends to the local mobility anchor.  Otherwise, the option MUST
      be included in the Proxy Binding Update message.  When this option
      is included, it is an indication to the local mobility anchor that
      the mobile access gateway is capable of supporting IP Traffic
      Offload support.  The TS format field of the IP Traffic Offload
      Selector Option MUST be set to a value of (0), indicating that the
      mobile access gateway is not proposing any specific offload policy
      for that mobility session, but a request to the local mobility
      anchor to provide the IP traffic offload flow selectors for that
      mobility session.

   o  The mobility access gateway MAY choose to include its proposed IP
      traffic offload flow selectors in the IP Traffic Offload Selector
      Option Section 4.  Including this offload traffic selectors serves
      as a proposal to the local mobility anchor, which the local



Gundavelli, et al.       Expires August 3, 2012                 [Page 6]

Internet-Draft    IPv4 Traffic Offload Selector Option      January 2012


      mobility anchor can override with its own offload policy, or agree
      to the proposed policy.  When including the offload traffic
      selectors, the TS format field of the IP Traffic Offload Selector
      Option MUST be set to the respective flow specification type.

   o  If there is no IP Traffic Offload Selector Option in the
      corresponding Proxy Binding Acknowledgement message, that the
      mobile access gateway receives in response to a Proxy Binding
      Update, it serves as an indication that the local mobility anchor
      does not support IP Traffic Offload support for that mobility
      session, and it implies the local mobility anchor cannot deliver
      IP flow selectors for that mobility session.  The mobile access
      gateway upon accepting the Proxy Binding Acknowledgement message
      MUST NOT enable any offload policy for that mobility session.  All
      the mobile node's IP flows MUST be tunneled back to the local
      mobility anchor.

   o  If there is IP Traffic Offload Selector Option in the
      corresponding Proxy Binding Acknowledgement message, it is an
      indication that the local mobility anchor has provided the IP
      traffic Offload selectors for that mobility session [RFC5213] and
      the identified IP flows have to be offloaded.  Considerations
      related to (M) flag MUST be applied.


4.  IP Traffic Offload Selector Option

   A new mobility option, IP 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 flow selectors for enabling IP traffic offload function
   at the mobile access gateway.

   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                        |    TS Format  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Traffic Selector ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+





Gundavelli, et al.       Expires August 3, 2012                 [Page 7]

Internet-Draft    IPv4 Traffic Offload Selector Option      January 2012


               Figure 3: IP 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.

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

   IP Traffic Offload Mode Flag
      This field indicates the offload mode.  If the (M) flag value is
      set to a value of (1), it is an indication that all the flows
      except the identified IP flow(s) in this mobility option needs to
      be offloaded at the mobile access gateway.  If the (M) flag value
      is set to a value of (0), it is an indication that the identified
      IP flow(s) needs to be offloaded at the mobile access gateway and
      all other IP flows associated with that mobility session needs to
      be tunneled to the local mobility anchor.

   TS Format
      An 8-bit unsigned integer indicating the Traffic Selector Format.
      The value of "0" is reserved and is used when there are no
      selectors to carry, relevant when the option is used as a
      capability indicator.  The value of (1) is assigned for IPv4
      Binary Traffic Selector [RFC6088].  All other values are reserved
      by IANA for future allocations.

   TS Selector
      A variable-length opaque field for including the traffic
      specification identified by the TS format field.  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].


5.  IANA Considerations

   This document requires the following two IANA actions.

   o  Action-1: This specification defines a new Mobility Header option,
      IP Traffic Offload Selector option.  This option is described in
      Section 4.  The Type value for this option needs to be assigned
      from the same numbering space as allocated for the other mobility
      options [RFC6275].



Gundavelli, et al.       Expires August 3, 2012                 [Page 8]

Internet-Draft    IPv4 Traffic Offload Selector Option      January 2012


   o  Action-2: The Sub-type field of the IP Traffic Offload Selector
      option introduces a new number space.  This number space needs to
      be managed by IANA, under the Registry, IP Traffic Offload
      Selector Type Registry.  This specification reserves the sub-type
      values of (0) and (1).  The value of "0" is reserved and is used
      when there are no selectors to carry, relevant when the option is
      used just as a capability indicator.  The value of (1) is assigned
      for IPv4 Binary Traffic Selector [RFC6088].  Approval of new sub-
      type values are to be made through IANA Expert Review.


6.  Protocol Configuration Variables

   This specification defines the following configuration variable that
   control the use of IP Traffic Offload support for a mobility session.
   The mobility entities, local mobility anchor and the mobile access
   gateway MUST allow these variables to be configured by the system
   management.  The configured values for these protocol variables MUST
   survive server reboots and service restarts.

   EnableIPTrafficOffloadSupport

         This flag indicates whether or not IP 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 IP Traffic offload support is
         disabled.

         When this flag on the mobile access gateway is set to a value
         of (1), the mobile access gateway MUST enable the IP Traffic
         offload support for a mobility session, specifically it MUST
         include the IP Traffic Offload Selector option in the Proxy
         Binding Update messages and offload the negotiated IP flows to
         the access network.  If the value of the flag is set to a value
         of (0), mobile access gateway MUST NOT enable IP Traffic
         Offload support and it MUST NOT include this option in the
         Proxy Binding Update.

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




Gundavelli, et al.       Expires August 3, 2012                 [Page 9]

Internet-Draft    IPv4 Traffic Offload Selector Option      January 2012


7.  Security Considerations

   The IP 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] and does not require any special
   security considerations.  Carrying IP 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
   traffic flows to the local 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 is already documented
   by the NAT specifications and which are unique to the approach
   specified in this document.


8.  Acknowledgements

   The authors would like to thank Ahmad Muhanna, Basavaraj Patil,
   Carlos Bernardos, Eric Voit, Frank Brockners, Hidetoshi Yokota, Mark
   Grayson, Pierrick Seite, Ryuji Wakikawa, and Steve Wood for all the
   discussions related to the topic of IP traffic offload.


9.  References

9.1.  Normative References

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

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

   [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.






Gundavelli, et al.       Expires August 3, 2012                [Page 10]

Internet-Draft    IPv4 Traffic Offload Selector Option      January 2012


9.2.  Informative References

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

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

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


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




Gundavelli, et al.       Expires August 3, 2012                [Page 11]

Internet-Draft    IPv4 Traffic Offload Selector Option      January 2012


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

   Email: rkoodli@cisco.com












































Gundavelli, et al.       Expires August 3, 2012                [Page 12]


Html markup produced by rfcmarkup 1.109, available from https://tools.ietf.org/tools/rfcmarkup/