Slot Synchronization of WDM Packet-Switched Slotted Rings: the WONDER Project

The WONDER project aims at designing and building a WDM packet-switched slotted ring network, with tunable transmitters and fixed receivers. An experimental prototype is under development at the laboratories of Politecnico di Torino. In this paper, we study two different strategies of slot synchronization for such networks: in the former, a slot synchronization signal is transmitted by the master station on a dedicated control wavelength; in the latter, slave nodes achieve slot synchronization aligning on data packets received from the master. Emphasis has been given to the architecture of the WONDER network. The performance of the two synchronization strategies, in terms of packet collision probability, has been evaluated by simulation. The technique based on transmitting a timing signal on a dedicated control wavelength resulted in achieving a better performance, although being more expensive due to need of an additional wavelength. However, the technique based on aligning on data packets received from the master should be not discarded, although attaining lower timing stability, especially if limiting the number of wavelengths and receivers is a strong requirement.