An efficient wavelength reservation protocol for lightpath establishment in all-optical networks (AONs)

This paper presents an efficient distributed control protocol for wavelength reservation in wide-area WDM all-optical networks. Our aim is 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. The protocol uses backward reservation with retries to reduce the chance of blocking. Backward reservation is normally considered to be better than forward reservation from the blocking point of view. Retries make it more efficient in that respect. We show through simulation that the protocol improves the success rate in connection establishment considerably without much incrementing the connection set-up delay, if we restrict the number of retries to 2 or 3. However, more retries do not always lead to a commensurate reduction in blocking while the average set-up time increases proportionately