Convergence time analysis of OSPF routing protocol using social network metrics

Abstract

The design philosophy of Open Shortest Path First Protocol, which is a widely deployed adaptive link state routing protocol, is to limit bandwidth requirements and attain quick recovery from failure (speed of convergence). The placement of the designated router has significant importance in convergence time. In literature, researchers have proposed approaches to improve convergence time. However, existing approaches reported hardware overhead and network congestion. Therefore, in this paper, the effect of the designated router’s placement on overall convergence time of an area is analysed. In the said perspective, the use of network centrality metrics for an optimal placement of designated router is proposed, which in return will reduce convergence time. The commonly used centrality metrics are betweenness centrality, closeness centrality, and degree centrality. This study employs the aforesaid centrality metrics for optimal placement of designated router. To demonstrate the effectiveness of using centrality metrics towards reducing convergence time, a tool named “Topology Analyzer” is developed to simulate the OSPF protocol convergence process. After simulation, the results revealed a convergence time reduction of 22% by selecting a designated router using centrality metrics. Furthermore, this work is evaluated by comparing the convergence time of traditional priority based designated router election process of the OSPF routing protocol.