BGP safety with spurious updates

Abstract

Abstract-We explore BGP safety, the question of whether a BGP system converges to a stable routing, in light of several BGP implementation features that have not been fully included in the previous theoretical analyses. We show that Route Flap Damping, MRAI timers, and other intra-router features can cause a router to briefly send "spurious" announcements of less-preferred routes. We demonstrate that, even in simple configurations, this short-term spurious behavior may cause long-term divergence in global routing. We then present DPVP, a general model that unifies these sources of spurious announcements in order to examine their impact on BGP safety. In this new, more robust model of BGP behavior, we derive a necessary and sufficient condition for safety, which furthermore admits an efficient algorithm for checking BGP safety in most practical circumstances -two complementary results that have been elusive in the past decade's worth of classical studies of BGP convergence in more simple models. We also consider the implications of spurious updates for well-known results on dispute wheels and safety under filtering.

Using routers to build logic circuits: How powerful is BGP?

“…This effectively imposes a partial order on the exchange of BGP updates. Previous lower bounds for BGP related problems have been proved in models that allow BGP messages to be arbitrarily (even if not indefinitely) delayed [2], [3], [10], [11], [12], [13], [14]. Moreover, the rest of the literature studied BGP from a game-theoretic perspective, where ASes act as players and BGP policies as players' strategies.…”