Network Working Group                                          G. Huston
Request for Comments: 5396                                 G. Michaelson
Category: Standards Track                                          APNIC
                                                          December 2008


       Textual Representation of Autonomous System (AS) Numbers

Status of This Memo

  This document specifies an Internet standards track protocol for the
  Internet community, and requests discussion and suggestions for
  improvements.  Please refer to the current edition of the "Internet
  Official Protocol Standards" (STD 1) for the standardization state
  and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

  Copyright (c) 2008 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 to this document.

Abstract

  A textual representation for Autonomous System (AS) numbers is
  defined as the decimal value of the AS number.  This textual
  representation is to be used by all documents, systems, and user
  interfaces referring to AS numbers.

Table of Contents

  1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 2
  2.  Taxonomy of Representation Formats  . . . . . . . . . . . . . . 2
  3.  Representation of AS Number Values  . . . . . . . . . . . . . . 2
  4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 3
  5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 3
  6.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 3
  7.  Informative References  . . . . . . . . . . . . . . . . . . . . 3








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1.  Introduction

  A textual representation for Autonomous System (AS) numbers is
  defined as the decimal value of the AS number.  This textual
  representation is to be used by all documents, systems, and user
  interfaces referring to AS numbers.

  This document notes a number of potential representation formats and
  proposes the adoption of a decimal value notation for AS numbers, or
  "asplain" according to the representation taxonomy described here.

2.  Taxonomy of Representation Formats

  A taxonomy of representation for AS numbers is as follows:

  asplain
     refers to a syntax scheme of representing all AS numbers using
     decimal integer notation.  Using asplain notation, an AS number of
     value 65526 would be represented as the string "65526" and an AS
     number of value 65546 would be represented as the string "65546".

  asdot+
     refers to a syntax scheme of representing all AS numbers using a
     notation of two integer values joined by a period character: <high
     order 16-bit value in decimal>.<low order 16-bit value in
     decimal>.  Using asdot+ notation, an AS number of value 65526
     would be represented as the string "0.65526" and an AS number of
     value 65546 would be represented as the string "1.10".

  asdot
     refers to a syntax scheme of representing AS number values less
     than 65536 using asplain notation and representing AS number
     values equal to or greater than 65536 using asdot+ notation.
     Using asdot notation, an AS number of value 65526 would be
     represented as the string "65526" and an AS number of value 65546
     would be represented as the string "1.10".

3.  Representation of AS Number Values

  To avoid confusion, a single textual notation is useful for
  documentation, configuration systems, reports, and external tools and
  information repositories.  The decimal value representation, or
  "asplain" is proposed as the textual notation to use for AS numbers.

  The "asplain" representation represents the number as its decimal
  value, without any field delimiter, corresponding to the lack of any
  internal structure required by the use of AS numbers in the inter-
  domain routing context.



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4.  IANA Considerations

  IANA Registries should use decimal representation ("asplain") for AS
  numbers.

5.  Security Considerations

  This document does not refer to matters associated with security of
  routing systems.

6.  Acknowledgments

  The terminology of "asplain", "asdot", and "asdot+" was originally
  devised and described by Juergen Kammer in January 2007 [KAMMER2007].

7.  Informative References

  [KAMMER2007]  Kammer, J., "AS Number Formats", Jan 2007,
                <http://quagga.ncc.eurodata.de/asnumformat.html>.

Authors' Addresses

  Geoff Huston
  Asia Pacific Network Information Centre

  EMail: [email protected]


  George Michaelson
  Asia Pacific Network Information Centre

  EMail: [email protected]



















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