A New Backup Topology Design Method for Congestion Avoidance in IP Fast Reroute

Abstract

We present a backup topology design method to avoid congestion in IP Fast Reroute. IP Fast Reroute techniques prepare backup topologies used to determine backup routes after a network failure. However, using more backup topologies consumes a lot of network resources. Reducing the nu mber o f backup topologies is a problem, as some lin ks becomes overloaded. In this paper, we present a backup topology design method that splits the traffic on high load links to other links by considering network conditions, such as the traffic matrix or topology. The main idea of our method is the introduction of a concept called a Special Node, which is a node with a h igher node degree, in the backup topology. We quantitatively illustrate the effectiveness of our method in terms of maximu m lin k load reduction. The results show that, with the same nu mber of backup topologies as the conventional method, our method can reduce congestion by 75%. It is effective for various topology models and not dependent to the network size. In this paper, we demonstrate that by selecting about 20% of the nodes as Special Nodes is very effect ive, part icularly in large networks selecting Special Nodes whilst considering node position gives maximu m effect. In this paper, we present that using our approach of selecting Special Nodes in the backup topology and then maximize the number of available links to the Special Nodes we can avoid congestion in IP Fast Reroute.