Distributed QoS monitoring and edge-to-edge QoS aggregation to manage end-to-end traffic flows in Differentiated Services networks

The Differentiated Services (DiffServ) framework has been proposed by the IETF as a simple service structure that can provide different Quality of Service (QoS) to different classes of packets in IP networks. IP packets are classified into one of a limited number of service classes, and are marked in the packet header for easy classification and differentiated treatments when transferred within a DiffServ domain. The DiffServ framework defines simple and efficient QoS differentiation mechanisms for the Internet. However, the original DiffServ concept does not provide a complete QoS management framework. Since traffic flows in IP networks are unidirectional from one network point to the other and routing paths and traffic demand get dynamically altered, it is important to monitor end-to-end traffic status, as well as traffic status in a single node. This paper suggests a distributed QoS monitoring method that collects the statistical data of each service class in every DiffServ router and calculates edge-to-edge QoS of the aggregated IP flows by combining routing topology and traffic status. A formal modeling of edge-to-edge DiffServ flows and algorithms for aggregating edge-to-edge QoS is presented. Also an SNMP-based QoS management prototype system for DiffServ networks is presented, which validates our QoS management framework and demonstrates useful service management functionality.