BGP Behavior through Analysis of Prefix Beacons

We are analyzing BGP beacons which are announced and withdrawn, usually within two hour intervals. These announcements and more particularly the withdraws have an effect on neighboring prefixes and down the line to their neighbors as well. We are conducting analysis on the number of updates that are propagated as a result of these events. We then look at the number of updates which could have been eliminated if route flap damping had been installed on the routers. We also analyze the relative convergence period associated with each beacon event and how it is correlated to the number of update messages collected by RouteViews[4]. I. WHAT IS A BGP BEACON The Border Gateway Protocol (BGP) is the central agent used to conduct data through the internet. A large group of networks put together have a gateway router which communicates to the internet at large. All data packets which are not meant for the immediate network go through this gateway router into the global internet through this router. This router has a prefix which is associated with it and this is how other networks identify it. Once a packet leaves your local prefix and enters the BGP it can take a number of different paths specified at each router to reach its destination. A number of previous analytical and measurement studies have shown the existence of BGP path exploration and a slow convergence in the operational Internet routing system, which can potentially lead to sever performance problems in data delivery. [1] This path exploration suggests that some BGP routers, in response to a path failure, may try a number of transient paths before settling and declaring a new best path or declaring a destination unreachable. This may cause the entire network to take a long time to settle and converge to the final decision, which causes slow routing convergence. An example of a failed path and resulting path exploration is depicted in figure 1. Figure 1: Failed Path and Resulting Path