An Implementation of Optimal Dynamic Load Balancing Based on Multipath IP Routing

We develop a protocol through which multipath enabled IP routers collectively engage in dynamic traffic engineering, to optimize performance in concert with legacy TCP congestion control. We build on recent theory which shows a globally optimum resource allocation across the TCP/IP layers can be achieved through control of rates and multipath routing fractions following a consistent congestion signal. In this work we fully develop, in an ns2 simulation environment, the required multipath IP layer consistent with prevailing loss-based TCP protocols, with the additional requirement that individual TCP connections should be routed through single paths. The solution involves a generalization of distance vector protocols where routing metrics reflect loss probabilities. We demonstrate through simulations the stability and performance of the resulting protocol in combination with TCP, and we comment on the complexity of the implementation.