A Transport Protocol for Dedicated End-to-End Circuits

Connection-oriented networks that offer guaranteed-rate circuits are being proposed as a solution to meet the high-end networking needs of distributed scientific research. This paper describes a transport protocol for data transfer across dedicated end-to-end circuits. We call this protocol Circuit-TCP (C-TCP). The key feature of C-TCP is to maintain a fixed sending rate, as closely matched to the circuit rate as possible, with the aim of achieving high circuit utilization. C-TCP is implemented by modifying TCP code in Linux. Experiments on a wide-area experimental circuit-switched testbed show that C-TCP is able to fully utilize circuit bandwidth and sustain a high circuit utilization. The challenge in this work lay in matching the variability inherent in general-purpose end hosts with the monotonic nature of circuits.