Forward reservation protocol with immediate unlock (FRP-IU) for dynamic lightpath establishment in all-optical networks (AONs)

This paper presents a distributed control protocol for wavelength reservation in wide-area WDM all-optical networks. The protocol aims to establish wavelength-continuous lightpaths dynamically and efficiently so as to minimize the overall blocking probability at the cost of a nominal increase in control overhead. It uses forward reservation with immediate unlocking of unnecessary wavelengths at intermediate nodes to reduce the chance of blocking. Forward reservation is normally considered to be better than backward reservation from the point of view of set-up delay. Immediate unlock facility makes it more efficient in terms of blocking probability. We show through simulation that the protocol improves the success rate in connection establishment (considerably for low aggressiveness) without much incrementing the control overhead.