Performance Analysis of OSPF Routing Protocol Under Single and Multiple Link Failure

Abstract

This study aims at highlighting OSPF (Open Shortest Path First) routing technique and its performance under different network failures. A single failure in high-speed networks even for fraction of second can disrupt millions of users. Therefore it is imperative to analyze performance of routing protocol under network failure. In this paper, OSPF routing technique is examined under single and multiple link failures. Investigations are performed on basis of average E2E (end to end) delay, throughput and jitter. In this investigation, convergence time for link failures is calculated. It is observed that network has least average E2E delay when working path does not experience any failure. Under single link failure, average E2E delay is least when failed link is nearest to the source node. Under double link failure, average E2E delay is maximum when failed links are farthest apart. Convergence time for multiple link failure is more than single link failure. It is observed that convergence is least for failed link immediately connected to the source node. As observed from plots, network achieves high throughput when working path does not experience any failure and throughput reduces for multiple link failures. Average jitter is maximum for the network without failure and its value reduces for multiple link failures. The investigations in this paper provide insight into the performance of OSPF routing technique. Analysis performed and values of performance metrics obtained for various link failures provide knowledge of critical links and backup routes with respect to application specific QoS (Quality of Service) requirements.