Inter-domain traffic engineering for tactical wireless networks using BGP

In the tactical Internet, inter-domain links consist mostly of unreliable and low bandwidth wireless links. To enable seamless routing across different Autonomous Systems (ASes), we propose an inter-domain Traffic Engineering (TE) scheme to reroute traffic when congestion occurs. There are two components for the TE scheme. First, a Traffic Splitting (TS) scheme is used for load balancing among parallel links connecting two ASes. By formulating traffic splitting as a non-linear programming problem, we minimize either the sum of packet delay or average packet delay between two ASes. Second, there is a Random Spanning Tree (RST) scheme. When traffic splitting fails to resolve congestion, we invoke the RST scheme to determine the set of optimal spanning trees for each AS. All inter-domain traffic is then rerouted accordingly on the new set of trees. The TE scheme resides in a centralized routing agent, which monitors network information and invokes the TS and RST schemes when congestion is detected. We implemented the TE scheme on QualNet and show that the TE scheme improves throughput and delay performance over several network scenarios. We also implemented the TE scheme in a testbed using Cisco routers. We demonstrate successfully that the TE scheme is responsive to real-time network data, rerouting traffic as needed to resolve congestion.