Intelligent Hierarchical Coordination Fault-Tolerant Routing Method Under End-to-End Quality of Service Protection in Multidomain Softwarized Networks

The paper presents research on the delay-based intelligent hierarchical coordination fault-tolerant inter-domain QoS-routing method designed for use in softwarized networks with multidomain architecture. The method aims at QoS ensuring under bandwidth and average end-to-end packet delay. It protects the inter-domain router while calculating the primary and backup paths. The essence of the intelligent hierarchical-coordination fault-tolerant QoS-routing method is the concurrent computation of primary and backup inter-domain routes when QoS requirements for bandwidth and average end-to-end delay are met for each flow. The flow-based optimization model of inter-domain QoS routing with the protection of inter-domain border routers underlies the method. The optimal inter-domain routes are calculated using the two-level goal coordination method. The domain controllers at the lower level calculate the set of primary and backup paths considering the selected routing metric. At the same time, the network controller at the upper level aims to coordinate lower-level decisions by ensuring inter-domain route connectivity and end-to-end delay. Therefore, the task of guaranteeing the end-to-end QoS is solved not at the domain controllers level but at the SDN controller level by performing gradient coordination procedures and machine learning algorithms. Hence, the offered method increases inter-domain routing flexibility and ensures QoS and fault tolerance.