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The Address plus Port (A+P) Approach to the IPv4 Address Shortage (RFC6346) Disclosure Number: IPCOM000212922D
Original Publication Date: 2011-Aug-01
Included in the Prior Art Database: 2011-Dec-01
Document File: 76 page(s) / 90K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

R. Bush: AUTHOR [+1]


This document describes a technique to deal with the imminent IPv4 address space exhaustion. Many large Internet Service Providers (ISPs) face the problem that their networks' customer edges are so large that it will soon not be possible to provide each customer with a unique public IPv4 address. Therefore, although undesirable, address sharing, in the same molds as NAT, is inevitable.

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Internet Engineering Task Force (IETF)                      R. Bush, Ed. Request for Comments: 6346                     Internet Initiative Japan Category: Experimental                                       August 2011 ISSN: 2070-1721

    The Address plus Port (A+P) Approach to the IPv4 Address Shortage


   We are facing the exhaustion of the IANA IPv4 free IP address pool.    Unfortunately, IPv6 is not yet deployed widely enough to fully    replace IPv4, and it is unrealistic to expect that this is going to    change before the depletion of IPv4 addresses.  Letting hosts    seamlessly communicate in an IPv4 world without assigning a unique    globally routable IPv4 address to each of them is a challenging    problem.

   This document proposes an IPv4 address sharing scheme, treating some    of the port number bits as part of an extended IPv4 address (Address    plus Port, or A+P).  Instead of assigning a single IPv4 address to a    single customer device, we propose to extend the address field by    using bits from the port number range in the TCP/UDP header as    additional endpoint identifiers, thus leaving a reduced range of    ports available to applications.  This means assigning the same IPv4    address to multiple clients (e.g., Customer Premises Equipment (CPE),    mobile phones), each with its assigned port range.  In the face of    IPv4 address exhaustion, the need for addresses is stronger than the    need to be able to address thousands of applications on a single    host.  If address translation is needed, the end-user should be in    control of the translation process -- not some smart boxes in the    core.

Bush                          Experimental                      [Page 1]
 RFC 6346                A+P Addressing Extension             August 2011

 Status of This Memo

   This document is not an Internet Standards Track specification; it is    published for examination, experimental implementation, and    evaluation.

   This document defines an Experimental Protocol for the Internet    community.  This document is a product of the Internet Engineering    Task Force (IETF).  It represents the consensus of the IETF    community.  It has received public review and has been approved for    publication by the Internet Engineering Steering Group (IESG).  Not    all documents approved by the IESG are a candidate for any level of    Internet Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,    and how to provide feedback on it may be obtained at

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the    document authors.  All rights re...