Rational ASes and Traffic Attraction: Incentives for honestly announcing paths in BGP
Prior work on modeling interdomain routing assumed that autonomous systems (ASes) are interested only in obtaining the best possible outgoing path for their traffic to a destination. In reality, many more factors can influence the ``rational behavior'' of an AS; here we consider a natural model in which ASes are also interested in attracting incoming traffic, either out of greed (since other ASes pay it to carry their traffic), or malice (so it can drop, modify, or spoof packets). This model of rationality induces situations where an AS has an incentive to send Border Gateway Protocol (BGP) announcements that do not correspond to the AS-level paths that packets traverse in the data plane. In this work, we ask what enhancements to BGP and/or restricted classes of routing policies can ensure that ASes will have no incentive to lie about data-plane paths. We find that while protocols like Secure BGP are necessary, they are in general not sufficient unless ASes are only inte
rested in the next hop that their traffic takes to its destination. Our game-theoretic analysis highlights the high cost of ensuring that BGP path announcements match data-plane forwarding paths.