UNITE-an architecture for lightweight signaling in ATM networks

Networks support a wide range of applications with diverse service quality requirements. This demands distinct identification of flows according to their requirements, and the ability to service them differently. Different networking technologies have been evolving towards this common goal. ATM is cost-efficient by exploiting switching. But signaling is slow making ATM unattractive for bursty data traffic. One difficulty with ATM signaling is the inextricable connection between basic connectivity and QoS management. Consequently, every flow, even a best-effort flow suffers the overhead of end-to-end connection establishment. We propose a new lightweight architecture for ATM signaling called UNITE. The fundamental philosophy of UNITE is the separation of connectivity from QoS control. This eliminates the round-trip connection setup delay before initiating data transmission. Using a single cell with proper encoding, we avoid the overhead of reassembly and segmentation on the signaling channel, and enable hardware implementation. Performing QoS negotiation in-band, allows the switches in the path to process QoS-requests in parallel, facilitates connection specific control policies, supports both sender and receiver initiated QoS, and allows for uniform treatment of unicast and multicast connections. UNITE supports variegated multicast trees.