Open and closed loop control in integrated services networks

This paper introduces and analyzes two basic network elements: time-dependent servers and time-dependent service curve schedulers. Time-dependent servers model network elements that are explicitly characterized by an input-output map, and include as special cases regulators and reflection maps. Time-dependent service curve schedulers model elements which assure a lower bound on the service provided to an individual session. This general formulation allows for a unified treatment of these network elements, and provides some easy aggregation rules for networks of such elements. We present these rules and discuss several corollaries of this network calculus. In particular, we obtain bounds on delay, queue length and burstiness for feedforward networks as well as networks with feedback