Minimizing internal speedup for performance guaranteed optical packet switches

Providing QoS guarantees for Internet services is very important. It evokes the issue that packet switches should provide guaranteed performance (i.e. 100% throughput with bounded worst-case delay). Optical switching technology is widely considered as an excellent solution for packet switches in future networks. However, to achieve guaranteed performance in optical packet switches, an internal speedup is required due to the existence of reconfiguration overhead. How to reduce the internal speedup is the main concern for making these switches practical. In this paper, we first derive the internal speedup S as a function of the number of switch configurations N_S and the reconfiguration overhead δ, or S=f(N_S,δ). We show that the recently proposed ADJUST algorithm is flawed. Based on the internal speedup function we derived, a new algorithm (ADAPTIVE), with time complexity of O((λ-1)N²logN), is proposed to minimize S.