RFC 1930 (rfc1930) - Page 1 of 10
Guidelines for creation, selection, and registration of an Autonomous System (AS)
Alternative Format: Original Text Document
Network Working Group J. Hawkinson
Request for Comments: 1930 BBN Planet
BCP: 6 T. Bates
Category: Best Current Practice MCI
March 1996
Guidelines for creation, selection, and registration
of an Autonomous System (AS)
Status of this Memo
This document specifies an Internet Best Current Practices for the
Internet Community, and requests discussion and suggestions for
improvements. Distribution of this memo is unlimited.
Abstract
This memo discusses when it is appropriate to register and utilize an
Autonomous System (AS), and lists criteria for such. ASes are the
unit of routing policy in the modern world of exterior routing, and
are specifically applicable to protocols like EGP (Exterior Gateway
Protocol, now at historical status; see [EGP]), BGP (Border Gateway
Protocol, the current de facto standard for inter-AS routing; see
[BGP-4]), and IDRP (The OSI Inter-Domain Routing Protocol, which the
Internet is expected to adopt when BGP becomes obsolete; see [IDRP]).
It should be noted that the IDRP equivalent of an AS is the RDI, or
Routing Domain Identifier.
Table of Contents
1. Introduction ............................................ 2
2. Motivation .............................................. 2
3. Definitions ............................................. 2
4. Common errors in allocating ASes ........................ 5
5. Criteria for the decision -- do I need an AS? .......... 5
5.1 Sample Cases ........................................... 6
5.2 Other Factors .......................................... 7
6. Speculation ............................................. 7
7. One prefix, one origin AS ............................... 8
8. IGP issues .............................................. 8
9. AS Space exhaustion ..................................... 8
10. Reserved AS Numbers .................................... 9
11. Security Considerations ................................ 9
12. Acknowledgments ........................................ 9
13. References ............................................. 9
14. Authors' Addresses ..................................... 10
Hawkinson & Bates Best Current Practice