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 MultiTopology 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

Analysis of Practical Aspects of Multi-Plane Routing-Based Load Balancing Approach for Future Link-State Convergent All-IP Access Networks

“…This extends the performance analysis of [16] where a single topology was examined, hence providing novel and more concrete conclusions compared to the first analysis of the early versions of MPR [12] (i.e. GW anchored traffic distribution scenario).…”

“…A reference scenario was studied for MPR in [11] and [12] where the RP structure's construct was such that only dedicated RPs (i.e. paths) for every Gateway (GW)-Aggregation Router (AR) pair were considered.…”

“…[15] contains a theoretical study of the offline's quality of RPs when extended with internal traffic routing paths subject to hop-constrained optimization. Early practical results with the added internal traffic distributions for one topology are presented in [16] with the readjusted online TE approach as compared with [11] and [12].…”

“…When applying the previously proposed offline algorithm [12] to build RPs connecting the IngressEgress pairs, it is not guaranteed that the shortest possible RP set in terms of hop-count would be selected. Therefore, the resultant paths would render long routes in terms of hop-count specially in case II where AR − AR pairs are also connected directly.…”

“…MPR is comprised of an offline TE method that serves to build logical Routing Planes (RPs) rendering a set of multiple shortest paths between all Ingress -Egress routers ahead of the traffic flow in the network that is then governed by an online TE approach. MPR's online TE approach was initially presented in [11] and [12] serving a practical purpose of an integrated solution of distributing IP sessions over RPs.…”