QoS Routing in IPv6 with Link-Utilization-Ratio Single Metric

Quality-of-service routing (QoSR) is a challenging NP-hard problem of IPv6 networks. For the sake of satisfying QoS requests of future multimedia applications, a novel LMA (link-utilization-ratio metric based routing Algorithm) is proposed. It takes only a single metric called LUR (link-utilization-ratio) as the link cost, which is advertised suitably by OSPFv3 LSAs of IPv6. It computes routing by extending Dijkstra´s method with the invariable complexity of O(|E|+|V|log|V|). It takes the characteristics of IPv6 into account. It favors paths with lower delay, fewer hops and higher link availability. It tries to bypass the congestive path and decrease routing overhead. Theoretical analysis proves that routing with LUR metric can bring performance improvements of other related routing metrics. A formula is provided as the criterion of choosing a better next hop to route packets. Extensive simulations show that, LMA not only outperforms the original OSPF scheme and its variants such as SWP and WSP in terms of average link-availability-ratio, average path delay and average path hop-count, but also has good adaptability to large-scale networks