Performance and cost comparison of concentrated and unconcentrated optical packet switches

In this paper, we propose a novel non-blocking optical packet switch (OPS) architecture, named OPS with input concentrators (OPS-IC). In OPS-IC multiple input concentrators are used to aggregate the incoming traffic into the switch fabric, and the fixed wavelength converters (FWCs) at the switch output are employed to solve the contention resolution. Accordingly, the physical size and the economic cost of the OPS node are decreased dramatically. A Markov model is introduced to evaluate the performance of OPS-IC. The closed-form expressions of packet loss ratio (PLR) and delay are given. Its performance is also compared with that of the well-known OPS structure with limited range wavelength converters (OPS-LRWC). In addition, a cost model which includes time analysis in relation to the maturity stage of the optical components has been applied. Both performance and cost comparisons show that the OPS-IC is much cheaper than OPS-LRWC while providing same performance.