Design and evaluation of a new multi-path incremental routing algorithm on software routers

In this paper we analyze intra-domain routing protocols improvements to support new features required by realtime services. In particular we introduce OSPF fast convergence and highlight the advantage of using a dynamic algorithm instead of the Dijkstra one to compute the shortest paths. Then we propose a new multi-path dynamic algorithm which uses multipath information to make a fast determination about the new shortest paths when a link failure occurs, reducing this way the network re-convergence time. To evaluate the proposed algorithm performance we have implemented it in the OSPF code of the Quagga open-source routing software. We compare our own algorithm with three different dynamic algorithms, like the one implemented in Cisco routers and the two others, well known in literature, proposed by Narvaez and Ramalingam-Reps. We show how, by exploiting multi-path information, our algorithm performs, in many case studies, better than the above algorithms, especially in a link failure scenario.