Combined Nonlinear Control of Flow Rate and Bandwidth for Vir- tual Paths in ATM based Networks

Multimedia and multiservice broadband networks (e.g. Broadband-ISDN and ATM based LANs) will be implemented using Asynchronous Transfer Mode (ATM). In this paper we consider the combined control problem of flow rate and bandwidth (capacity, service rate) at the virtual path level in ATM based networks under nonstationary conditions. A fluid flow model in the state variable form is used to describe the time varying mean behaviour of a virtual path. A nonlinear control approach is adopted to derive the control strategy for the single node, finite buffer and server, case. The performance of the proposed scheme is evaluated using analysis and simulations. Simulation results show that the proposed scheme achieves effective server and buffer utilisation (as predicted by analysis) and by appropriate choice of the control design variables it achieves zero cell loss (even for traffic demands, which if not controlled would suffer cell losses). Hence the proposed scheme avoids retransmissions which as a result would reduce network utilisation.