Comparison of proactive and reactive methods for IP fast restoration using localization algorithm

To shorten the time taken to restore an IP network after a failures, we previously proposed a proactive method that uses a localization algorithm to reduce the number of alternate routing tables in the past study. Although we showed that it shortened the restoration time from failures by switching the routing tables to alternate ones set up for handling the failures, deployability remained a problem to be solved. In this paper, we propose a reactive method that enables the step-by-step deployment through the use of a tunneling technique. It also uses the localization algorithm to decide the tunnel´s end-point. Experimental results show its easy deployability and smaller computing resource requirements, such as the number of alternate routing tables and required CPU time, compared with the proactive method. Since the reactive method does not require routing table updates at intermediate nodes, it can restore packet reachabilities faster than the proactive method.