Robust Congestion Controller for a Single Virtual Circuit in Connection-Oriented Communication Networks

In this contribution, we consider the problem of data flow control for a single virtual connection in communication networks. The connection is described by the maximum link capacity, the non-negligible propagation delay and an unknown, time-varying data loss rate. We propose a discrete-time sliding mode controller, which generates non-negative and upper bounded transmission rates. In addition, it ensures that the queue length in the bottleneck link buffer is always limited. Moreover, with a sufficiently large memory buffer in the bottleneck node, it guarantees full utilization of the available bandwidth. The controller uses a dead-beat sliding hyperplane in order to ensure fast response to unknown changes of the link capacity and to an unpredictable data loss rate. However, if the straightforward dead-beat paradigm was used, unacceptably large transmission rates would be generated. Therefore, we use the reaching law approach in this chapter to decrease excessive magnitudes of the control signal at the start of the control process.