Commentary on Inter-Domain Routing in the Internet
RFC 3221
Document | Type |
RFC - Informational
(December 2001; No errata)
Was draft-iab-bgparch (iab)
|
|
---|---|---|---|
Author | Geoff Huston | ||
Last updated | 2013-03-02 | ||
Stream | IAB | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | IAB state | (None) | |
Consensus Boilerplate | Unknown | ||
RFC Editor Note | (None) |
Network Working Group G. Huston Request for Comments: 3221 Internet Architecture Board Category: Informational December 2001 Commentary on Inter-Domain Routing in the Internet Status of this Memo This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2001). All Rights Reserved. Abstract This document examines the various longer term trends visible within the characteristics of the Internet's BGP table and identifies a number of operational practices and protocol factors that contribute to these trends. The potential impacts of these practices and protocol properties on the scaling properties of the inter-domain routing space are examined. This document is the outcome of a collaborative exercise on the part of the Internet Architecture Board. Table of Contents 1. Introduction................................................. 2 2. Network Scaling and Inter-Domain Routing ................... 2 3. Measurements of the total size of the BGP Table ............ 4 4. Related Measurements derived from BGP Table ................ 7 5. Current State of inter-AS routing in the Internet .......... 11 6. Future Requirements for the Exterior Routing System ........ 14 7. Architectural Approaches to a scalable Exterior Routing Protocol........................................... 15 8. Directions for Further Activity ............................ 21 9. Security Considerations .................................... 22 10. References ................................................. 23 11. Acknowledgements ........................................... 24 12. Author's Address ........................................... 24 13. Full Copyright Statement ................................... 25 Huston Informational [Page 1] RFC 3221 Commentary on Inter-Domain Routing December 2001 1. Introduction This document examines the various longer term trends visible within the characteristics of the Internet's BGP table and identifies a number of operational practices and protocol factors that contribute to these trends. The potential impacts of these practices and protocol properties on the scaling properties of the inter-domain routing space are examined. These impacts include the potential for exhaustion of the existing Autonomous System number space, increasing convergence times for selection of stable alternate paths following withdrawal of route announcements, the stability of table entries, and the average prefix length of entries in the BGP table. The larger long term issue is that of an increasingly denser inter-connectivity mesh between ASes, causing a finer degree of granularity of inter-domain policy and finer levels of control to undertake inter-domain traffic engineering. Various approaches to a refinement of the inter-domain routing protocol and associated operating practices that may provide superior scaling properties are identified as an area for further investigation. This document is the outcome of a collaborative exercise on the part of the Internet Architecture Board. 2. Network Scaling and Inter-Domain Routing Are there inherent scaling limitations in the technology of the Internet or its architecture of deployment that may impact on the ability of the Internet to meet escalating levels of demand? There are a number of potential areas to search for such limitations. These include the capacity of transmission systems, packet switching capacity, the continued availability of protocol addresses, and the capability of the routing system to produce a stable view of the overall topology of the network. In this study we will look at this latter capability with the objective of identifying some aspects of the scaling properties of the Internet's routing system. The basic structure of the Internet is a collection of networks, or Autonomous Systems (ASes) that are interconnected to form a connected domain. Each AS uses an interior routing system to maintain a coherent view of the topology within the AS, and uses an exterior routing system to maintain adjacency information with neighboring ASes to create a view of the connectivity of the entire system. Huston Informational [Page 2] RFC 3221 Commentary on Inter-Domain Routing December 2001 This network-wide connectivity is described in the routing table used by the BGP4 protocol (referred to as the Routing Information Base, orShow full document text