Revisiting the BGP communities usage

Abstract

BGP is an interdomain routing protocol, used to learn and propagate prefixes in the Internet. It is used by ASes to exchange reachability information. To indicate the reachability of a subnet, an AS can send route advertisements to its neighbouring ASes. When multiple routes are available to join a given destination, the routing decision taken by BGP to select the best route relies on mechanisms that can be enforced by BGP attributes. This thesis focuses on one of these attributes: the BGP community. The BGP community attribute is a means to label a route to add information to it.

Measurements and analyses spanning the history of BGP communities are used to evaluate the usage of that attribute. A taxonomy refining the proposition made by Donnet and Bonaventure ten years ago is proposed to enable the classification of the BGP communities. A quantification of the BGP communities based on that taxonomy contributes to uncover the recent trends ruling the usage of BGP communities. A website gathering information about the communities of the studied ASes is presented (http://www.montefiore.ulg.ac.be/~bgp_communities/).