The Internet is composed of Autonomous Systems (ASes) or domains, i.e.,networks belonging to different administrative entities. Routing betweendomains/ASes is realised in a distributed way, over the Border Gateway Protocol(BGP). Despite its global adoption, BGP has several shortcomings, like slowconvergence after routing changes, which can cause packet losses and interruptcommunication even for several minutes. To accelerate convergence, inter-domainrouting centralization approaches, based on Software Defined Networking (SDN),have been recently proposed. Initial studies show that these approaches cansignificantly improve performance and routing control over BGP. In this paper,we complement existing system-oriented works, by analytically studying thegains of inter-domain SDN. We propose a probabilistic framework to analyse theeffects of centralization on the inter-domain routing performance. We derivebounds for the time needed to establish data plane connectivity between ASesafter a routing change, as well as predictions for the control-planeconvergence time. Our results provide useful insights (e.g., related to thepenetration of SDN in the Internet) that can facilitate future research. Wediscuss applications of our results, and demonstrate the gains throughsimulations on the Internet AS-topology.
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