Policy-based BGP-control architecture for inter-AS routing adjustment

Unexpected temporal and spatial changes of interdomain routing paths often lead to the necessity of on-demand routing adjustment among independently managed ASs. For resolving this problem, we have developed a BGP-control architecture called Virtual Router (VR) for controlling conventional BGP routers from outside without any protocol extensions. The VR combined with a multi-agent system (MAS) can be applied for the inter-AS routing adjustment for transit ISPs and their customer ASs. This architecture makes incremental deployment possible. The VR controls interdomain routing by dynamically changing forwarding paths among alternative BGP entries in multiple border routers. Each agent, which interprets a policy description for acquiring and analyzing network status, exchanges interdomain routing adjustment preferences when an adjustment is required, and coordinates where and how to change routing on the basis of feedback. Evaluation results indicate the validity and effectiveness of the basic design of our system in some control scenarios, where an AS tries to balance inbound traffic flowing via neighboring BGP peers.