BGP Communities for Data Collection
RFC 4384

Network Working Group                                           D. Meyer
Request for Comments: 4384                                 February 2006
BCP: 114
Category:  Best Current Practice

                  BGP Communities for Data Collection

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.

Copyright Notice

   Copyright (C) The Internet Society (2006).

Abstract

   BGP communities (RFC 1997) are used by service providers for many
   purposes, including tagging of customer, peer, and geographically
   originated routes.  Such tagging is typically used to control the
   scope of redistribution of routes within a provider's network and to
   its peers and customers.  With the advent of large-scale BGP data
   collection (and associated research), it has become clear that the
   information carried in such communities is essential for a deeper
   understanding of the global routing system.  This memo defines
   standard (outbound) communities and their encodings for export to BGP
   route collectors.

Meyer                    Best Current Practice                  [Page 1]
RFC 4384          BGP Communities for Data Collection      February 2006

Table of Contents

   1. Introduction ....................................................2
   2. Definitions .....................................................3
      2.1. Peers and Peering ..........................................3
      2.2. Customer Routes ............................................3
      2.3. Peer Routes ................................................3
      2.4. Internal Routes ............................................4
      2.5. Internal More Specific Routes ..............................4
      2.6. Special Purpose Routes .....................................4
      2.7. Upstream Routes ............................................4
      2.8. National Routes ............................................4
      2.9. Regional Routes ............................................4
   3. RFC 1997 Community Encoding and Values ..........................5
   4. Community Values for BGP Data Collection ........................5
      4.1. Extended Communities .......................................7
      4.2. Four-Octet AS Specific Extended Communities ................9
   5. Note on BGP UPDATE Packing ......................................9
   6. Acknowledgements ................................................9
   7. Security Considerations ........................................10
      7.1. Total Path Attribute Length ...............................10
   8. IANA Considerations ............................................10
   9. References .....................................................11
      9.1. Normative References ......................................11
      9.2. Informative References ....................................11

1.  Introduction

   BGP communities [RFC1997] are used by service providers for many
   purposes, including tagging of customer, peer, and geographically
   originated routes.  Such tagging is typically used to control the
   scope of redistribution of routes within a provider's network and to
   its customers and peers.  Communities are also used for a wide
   variety of other applications, such as allowing customers to set
   attributes such as LOCAL_PREF [RFC1771] by sending appropriate
   communities to their service provider.  Other applications include
   signaling various types of Virtual Private Networks (VPNs) (e.g.,
   Virtual Private LAN Service (VPLS) [VPLS]), and carrying link
   bandwidth for traffic engineering applications [RFC4360].

   With the advent of large-scale BGP data collection [RV] [RIS] (and
   associated research), it has become clear that the geographical and
   topological information, as well as the relationship the provider has
   to the source of a route (e.g., transit, peer, or customer), carried
   in such communities is essential for a deeper understanding of the
   global routing system.  This memo defines standard communities for
   export to BGP route collectors.  These communities represent a
   significant part of information carried by service providers as of

Meyer                    Best Current Practice                  [Page 2]
RFC 4384          BGP Communities for Data Collection      February 2006

   this writing, and as such could be useful for internal use by service
   providers.  However, such use is beyond the scope of this memo.
   Finally, those involved in BGP data analysis are encouraged to verify
   with their data sources as to which peers implement this scheme (as