An open architecture for transparently embedding advanced traffic control functionality in ATM switches

Current ATM switches offer only a limited potential for traffic control. Furthermore, this functionality is provided in a monolithic "black box" fashion, dependent on the manufacturers' proprietary architectures. This arrangement does not allow network operators and/or value-added service providers to adjust or upgrade the traffic control algorithms either for more efficient operation or for deploying customized traffic control policies and/or protocols. In addressing this problem, the paper proposes an open architecture that enables portable installation and transparent high-level operation of a large set of traffic control algorithms, The core of the proposed architecture consists of: a) an abstract information model that provides a virtual environment for portably deploying traffic control algorithms, by separating the functioning of these algorithms from the details of the switch hardware and low-level management/control software; b) a set of generic interfaces complying with the programmable network interfaces of the P1520 reference model; and c) a virtual signaling protocol. Besides presenting the architecture, the paper discusses at length a prototype implementation on an ATM network island. The implementation is based on the proposed architectural framework and makes use of intelligent software agents. This prototype is being used as a testbed for the comparative evaluation of traffic control algorithms.