Flow Oriented Approaches to QoS Assurance

The following flow-oriented architectures for quality of service assurance in IP networks are surveyed: Integrated Services, Connectionless Approach to QoS guarantees, Dynamic Packet State, Caspian Networks and Anagran, the Feedback and Distribution method, Flow-Based Differentiated Services, Flow-Aware Networking, the Flow-State-Aware transport, and Flow-Aggregate-Based services. The reasons why flow-awareness attracted so much attention are explained, and the current studies as well as the development history of the solutions are presented. The following features of the discussed architectures are compared: flow definition, classes of service, architecture, and signaling. Also, their pros and cons, complexity, and scalability, as well as perspectives are assessed.