Experimental WDM Packet Networks for Metro Applications: the RingO and Wonder Projects

This paper presents the activities carried out at Politecnico di Torino, Italy, on an advanced ring-based WDM optical packet network suitable for a high-capacity metro environment. We present two alternative architectural designs, and elaborate on the effectiveness of optical with respect to electronic technologies, trying to identify an optimal mix of the two technologies [1]. The first presented architecture refers to a research project called RingO, which ended in 2002, while the second one refers to the current ongoing project Wonder. Both projects are funded by the Italian Ministry for Education and Research (MIUR). We present the design and prototyping of a simple but efficient access control protocol, based upon the equivalence of the proposed network architecture with input-buffering packet switches. We discuss the problem of node allocation to WDM channels, which can be viewed as a particular optical network design problem. The main contribution of the paper is the identification and experimental validation of an innovative optical network architecture, which is feasible and cost effective with technologies available today, and can be a valid alternative to more consolidated solutions in metro applications.