Stateless IPv4 Network Address Translation
draft-tsou-stateless-nat44-00

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Document Type Active Internet-Draft (individual)
Authors Tina Tsou  , Will LIU  , Simon Perreault 
Last updated 2012-06-19
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Network Working Group                                            T. Tsou
Internet-Draft                                 Huawei Technologies (USA)
Intended status: Standards Track                                  W. Liu
Expires: December 21, 2012                           Huawei Technologies
                                                            S. Perreault
                                                                Viagenie
                                                           June 19, 2012

               Stateless IPv4 Network Address Translation
                     draft-tsou-stateless-nat44-00

Abstract

   This memo describes a protocol for decentralizing IPv4 NAT to the
   customer-premises equipment (CPE) such that no state information is
   kept on the central NAT device.  The CPE uses a restricted source
   port set that is encoded in its provisioned IPv4 WAN address.  The
   NAT device performs only strictly stateless address (not port)
   translation.

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
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   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
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on December 16, 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
   carefully, as they describe your rights and restrictions with respect

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   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.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Address Formats . . . . . . . . . . . . . . . . . . . . . . . . 4
   4.  CPE Provisioning  . . . . . . . . . . . . . . . . . . . . . . . 4
   5.  SLNAT44 Configuration . . . . . . . . . . . . . . . . . . . . . 5
   6.  Port Set Computation  . . . . . . . . . . . . . . . . . . . . . 5
   7.  CPE Operation . . . . . . . . . . . . . . . . . . . . . . . . . 7
   8.  SLNAT44 Operation . . . . . . . . . . . . . . . . . . . . . . . 7
     8.1.  Internal to External  . . . . . . . . . . . . . . . . . . . 7
     8.2.  External to Internal  . . . . . . . . . . . . . . . . . . . 7
     8.3.  Fragment Handling . . . . . . . . . . . . . . . . . . . . . 8
   9.  Security Considerations . . . . . . . . . . . . . . . . . . . . 8
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 8
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . . . 9
     11.1. Normative References  . . . . . . . . . . . . . . . . . . . 9
     11.2. Informative References  . . . . . . . . . . . . . . . . . . 9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 9

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1.  Introduction

   IPv4 address exhaustion has become world-wide reality.  NAT is one of
   the solutions to deal with the problem.  The drawbacks of traditional
   NAT include statefulness and the need to track transport-layer
   sessions.  This makes NAT complex, hard to scale up, and fragile.

   This document describes a method of deploying stateless NAT as a
   backwards-compatible evolution of an IPv4-only network.

   The assumed topology is illustrated in Figure 1.

               +-----+                   +---------+
    Home  -----+ CPE |---<ISP network>---+ SLNAT44 +---- Internet
   network     +-----+                   +---------+
                     ^                             ^
                     |                             |
                     +-- Internal Address          +--- External Address

                    Figure 1: Stateless NAT44 topology
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