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Internet Engineering Task Force                             J. Yamaguchi
Internet-Draft                                                       IIJ
Intended status: Informational                              Y. Shirasaki
Expires: July 7, 2012                                        S. Miyakawa
                                                      NTT Communications
                                                             A. Nakagawa
                                          Japan Internet Exchange (JPIX)
                                                               H. Ashida
                                                      IS Consulting G.K.
                                                         January 4, 2012


                        NAT444 addressing models
               draft-shirasaki-nat444-isp-shared-addr-07

Abstract

   This document describes addressing models of NAT444.  There are some
   addressing models of NAT444.  The addressing models have some issues
   of network behaviors, operations, and addressing.  This document
   helps network architects to use NAT444 after IPv4 address exhaustion.

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 July 7, 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
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents



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   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.

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
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   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.


































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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 4
   2.  Addressing Models . . . . . . . . . . . . . . . . . . . . . . . 4
     2.1.  Global Address  . . . . . . . . . . . . . . . . . . . . . . 4
     2.2.  Private Address . . . . . . . . . . . . . . . . . . . . . . 4
       2.2.1.  Policy Based Routing Issue  . . . . . . . . . . . . . . 4
       2.2.2.  Address Block Duplication Issue . . . . . . . . . . . . 4
       2.2.3.  Class-E Address (240/4) . . . . . . . . . . . . . . . . 4
       2.2.4.  ISP Shared Address  . . . . . . . . . . . . . . . . . . 5
   3.  Example Architectures . . . . . . . . . . . . . . . . . . . . . 5
     3.1.  Direct Routing inside CGN . . . . . . . . . . . . . . . . . 5
     3.2.  CGN Bypassing . . . . . . . . . . . . . . . . . . . . . . . 6
     3.3.  Global Address Customers inside CGN . . . . . . . . . . . . 7
   4.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 7
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8
   6.  Security Considerations . . . . . . . . . . . . . . . . . . . . 8
   7.  Normative References  . . . . . . . . . . . . . . . . . . . . . 8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 8
































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1.  Introduction

   NAT444 [I-D.shirasaki-nat444] is one of solutions after IPv4 address
   exhaustion.  ISP can select some addressing models of NAT444.  The
   addressing models have some issues of network behaviors, operations,
   and addressing.  This document describes these issues and solutions.
   It boosts up to deploy the IPv6 Internet.


2.  Addressing Models

   The key of addressing model is the address block between Customer
   Premises Equipment (CPE) and Carrier Grade NAT (CGN)
   [I-D.ietf-behave-lsn-requirements].  It's mentioned in this section.
   The best addressing model is "ISP Shared Address" which is defined in
   [I-D.shirasaki-isp-shared-addr] and briefly described in this
   section.

2.1.  Global Address

   ISP cannot assign IPv4 Global Address any more after the exhaustion.

2.2.  Private Address

   It has two major problems.

2.2.1.  Policy Based Routing Issue

   If both source and destination address of the packet are inside CGN,
   it has to go through CGN.  The reason is that some servers reject
   receiving packets when the source address of receiving packet is
   Private Address.  Therefore packets have to go through the CGN for
   rewriting the source address from Private Address to Global Address.
   Additionally, if Private Address and Global Address co-exist inside
   CGN, the ISP has to use Policy Based Routing (PBR).

2.2.2.  Address Block Duplication Issue

   The Private Address in ISP's network could conflict with its
   customer's network address.  Many CPEs between customer's network and
   ISP's network cannot route the packet under this situation.  To avoid
   this, ISP has to negotiate with its all customers not to use the
   reserved Private Address block.

2.2.3.  Class-E Address (240/4)

   It is known that some equipment such as routers and servers reject
   packets from or to this address block.  So, to use this address block



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   in ISP's network, ISP has to request its customers to replace their
   equipment.  In addition to that, ISP might have to replace their
   equipment when it doesn't handle Class-E address packets properly.

2.2.4.  ISP Shared Address

   ISP Shared Address is the newly defined IPv4 address block that is to
   be allocated from IANA free pool.  It doesn't have any problem.
   Spending some blocks from the exhausting IANA free pool could be
   regarded as a problem, but from long view, this problem is much
   smaller than its great merit.  ISP Shared Address is defined in
   [I-D.shirasaki-isp-shared-addr].


3.  Example Architectures

   This section explains example architectures how to design NAT444 with
   ISP Shared Address.

3.1.  Direct Routing inside CGN

   This architecture enables direct communication between customers
   inside same CGN.  It has the following advantages.

   o  The packets don't go through CGN.  (No hairpining)

   o  The customers inside CGN can use bidirectional applications (e.g.
      TV Conference, VPN).

   o  No need to use Policy Based Routing.


                 (The IPv4 Internet)
                          | Global Address
                     +----+----+
                     |   CGN   |
                     +----+----+
                          |
   ISP Shared +-----------+----------+ ISP Shared
      Address |      ..........      | Address
         +----+----+ :        : +----+----+
         | CPE NAT | :        : | CPE NAT |
         +----+----+ :        : +----+----+
      Private |      :        :      | Private
      Address |      v        v      | Address
         +----+----+            +----+----+
         |IPv4 Host|            |IPv4 Host|
         +---------+            +---------+



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3.2.  CGN Bypassing

   This architecture is bypassing the NAT function of CGN.  It has the
   following advantage.

   o  The customers inside an ISP can use bidirectional applications
      (e.g.  TV Conference, VPN).

   o  Any communication in single ISP doesn't consume CGN external port.

   o  ISP's servers outside CGN can access CPE. (e.g.  ICMP echo, SNMP,
      remote access)

   o  ISP's servers outside CGN can distinguish which customer's
      connection it receives. (e.g.  DNS, Mail)



    (The IPv4 Internet)
              |
              |                 +--------+ Network Monitor
              |                 | Server | (ICMP echo, SNMP)
              |                 +----+---+ DNS, Mail, Web, etc
       Global |                      |  ^
      Address +----------------------+  :
              |      ....................
              |      .        :      |
         +----+----+ :        : +----+----+ bypass NAT:
         |   CGN   | : bypass : |   CGN   | Dst=ISP's Global Address
         +----+----+ :  NAT   : +----+----+  or ISP Shared Address
   ISP Shared |      :        :      |
      Address |      :        :      | ISP Shared Address
         +----+----+ :        : +----+----+
         | CPE NAT | :        : | CPE NAT |
         +----+----+ :        : +----+----+
      Private |      :        :      | Private
      Address |      v        v      | Address
         +----+----+            +----+----+
         |IPv4 Host|            |IPv4 Host|
         +---------+            +---------+











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3.3.  Global Address Customers inside CGN

   This architecture enables co-existing Global Address and ISP Shared
   Address inside CGN.

   It enables direct communications from ISP Shared Address customer to
   Global Address customer inside same CGN.  It has the following
   advantage.

   o  The ISP can put ISP Shared Address customer and Global Address
      customer in the same concentrator.

   o  The customers inside CGN can use bidirectional applications (e.g.
      TV Conference, VPN).

   o  No need to use Policy Based Routing.



   (The IPv4 Internet)
            |
            | Global Address
       +----+----+
       |   CGN   | bypass NAT: Src/Dst=Global Address
       +----+----+
            | Global Address and ISP Shared Address co-existing
            +----------------------+
            |      .........       |
       +----+----+ :        : +----+----+
       | Firewall| :        : | CPE NAT |
       +----+----+ :        : +----+----+
     Global |      :        :      | Private
    Address |      v        :      | Address
      +-----+-----+           +----+----+
      |IPv4 Server|           |IPv4 Host|
      +-----------+           +---------+




4.  Acknowledgements

   Thanks for the input and review by Shirou Niinobe, Takeshi Tomochika,
   Tomohiro Fujisaki, Dai Nishino, JP address community members, AP
   address community members and JPNIC members.






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5.  IANA Considerations

   IANA is to allocate a certain size of address block from IANA free
   pool.  The size of it is described in [I-D.shirasaki-isp-shared-addr]


6.  Security Considerations

   There are no security considerations.


7.  Normative References

   [I-D.shirasaki-isp-shared-addr]
              Yamagata, I., Miyakawa, S., Nakagawa, A., Yamaguchi, J.,
              and H. Ashida, "ISP Shared Address",
              draft-shirasaki-isp-shared-addr-06 (work in progress),
              July 2011.

   [I-D.ietf-behave-lsn-requirements]
              Perreault, S., Yamagata, I., Miyakawa, S., Nakagawa, A.,
              and H. Ashida, "Common requirements for Carrier Grade NATs
              (CGNs)", draft-ietf-behave-lsn-requirements-05 (work in
              progress), November 2011.

   [I-D.shirasaki-nat444]
              Yamagata, I., Shirasaki, Y., Nakagawa, A., Yamaguchi, J.,
              and H. Ashida, "NAT444", draft-shirasaki-nat444-04 (work
              in progress), July 2011.


Authors' Addresses

   Jiro Yamaguchi
   Internet Initiative Japan Inc.
   Jinbocho Mitsui Bldg., 1-105 Kanda Jinbo-cho, Chiyoda-ku
   Tokyo  101-0051
   Japan

   Phone: +81 3 5205 6500
   Email: jiro-y@iij.ad.jp










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   Yasuhiro Shirasaki
   NTT Communications Corporation
   NTT Hibiya Bldg. 7F, 1-1-6 Uchisaiwai-cho, Chiyoda-ku
   Tokyo  100-8019
   Japan

   Phone: +81 3 6700 8530
   Email: yasuhiro@nttv6.jp


   Shin Miyakawa
   NTT Communications Corporation
   Granpark Tower 17F, 3-4-1 Shibaura, Minato-ku
   Tokyo  108-8118
   Japan

   Phone: +81 3 6733 8671
   Email: miyakawa@nttv6.jp


   Akira Nakagawa
   Japan Internet Exchange Co., Ltd. (JPIX)
   Otemachi Building 21F, 1-8-1 Otemachi, Chiyoda-ku
   Tokyo  100-0004
   Japan

   Phone: +81 90 9242 2717
   Email: a-nakagawa@jpix.ad.jp


   Hiroyuki Ashida
   IS Consulting G.K.
   12-17 Odenma-cho, Nihonbashi, Chuo-ku
   Tokyo  103-0011
   Japan

   Email: assie@hir.jp














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