UNITE: a framework for flexible QoS management

UNITE, our proposed lightweight signaling protocol for ATM, allows us to flexibly support QoS, while achieving efficiency for those flows that do not require substantial customization. UNITE efficiently supports a large number of best-effort flows by separating out the connectivity requirements from QoS processing. Connection setup is performed on the signaling channel while QoS processing is performed in-band. One of the important advantages of this approach is the ability to have QoS signaling initiated by any of the end-systems. Hence, we can smoothly support the RSVP-style of QoS setup by the receiver as well as UNI (User Network Interface)-style QoS setup by the source. The controller is separated from the high-speed switching. Most of the functions for QoS support are performed by the controller. By placing all the signaling for QoS negotiation in-band, UNITE isolates the QoS processing of one connection from another. We can now begin to have individual connections requiring different amounts of customization of their flows, ranging from simple best-effort connections that do not require any customization, to complex application-specific policies and processing that may be required in the network. In-band signaling allows us to provide considerable flexibility for future evolution of QoS support in the network. In-band signaling also removes from the common signaling channel the complexity of describing all the connection-specific information. This enables the signaling channel to have high performance for connection setup, where performance is critical.