QoS-aware multi-plane routing method for OSPF-based IP access networks

Abstract

This paper presents a study of a method termed, multi-plane routing, that maximizes path diversity in IP routing and is targeted for IP access networks (AN). The motivation for the work is in the specific shortcomings of the conventional intra-domain IP routing principles such as “shortest-path” and “best-effort” when applied in IP ANs. We generalize these networks as the transit between the access routers and gateway and they range from a simple tree to meshed tree topologies. The method uses Multi-Topology OSPF standardized by the IETF and instantiates multiple OSPF installations in networks, each installation utilizing a portion of the topology in the conventional manner, i.e. routing plane (RP). Hence, all links are utilized by having at least one standard OSPF routing installation including them in the paths between access router and gateway. The method functions on extensions in routers and simple packet tagging allowing the routers to install and separate between paths of each RP. Routing is facilitated by the proposed method’s algorithms for network planning and traffic engineering. The former is called the offline algorithm rendering the optimum number of RPs in an arbitrary topology by independently setting link weights for each plane. The latter is called the online algorithm that applies a policy-based routing scheme for dynamically selecting the best RP based on the introduced QoS-aware cost function. The paper concludes by significant improvements in throughput, packet loss rate, session blocking and delays for numerous cases of topologies differing in numbers of networks nodes and degrees of meshing.