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 Huston & Michaelson Standards Track [Page 1] RFC 5396 ASN Notation December 2008 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: .. 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. Huston & Michaelson Standards Track [Page 2] RFC 5396 ASN Notation December 2008 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, . Authors' Addresses Geoff Huston Asia Pacific Network Information Centre EMail: gih@apnic.net George Michaelson Asia Pacific Network Information Centre EMail: ggm@apnic.net Huston & Michaelson Standards Track [Page 3]