Enhancing Shortest Path Routing for Resilience and Load Balancing

This paper develops a new resilient multipath routing technique, referred to as SPT-DAG, that has the following characteristics: (1) provides multipath routing over directed acyclic graphs (DAG); (2) the shortest path tree is guaranteed to be part of the DAG; and (3) provides guaranteed recovery from single link failures. We develop polynomial time algorithm to compute the SPT-DAG and a routing protocol to forward packets over the SPT-DAG using one overhead bit in the packet. We consider different load-balancing approaches for forwarding a packet when the packet has not encountered a failure. Through extensive flow-based simulations, we show that the SPT-DAG performs significantly better than those approaches that exclusively target load balancing or resiliency.