Destination-initiated wavelength-weighted reservation protocol in WDM rings

In networks that require dynamic assignment of wavelengths, it is known that destination initiated reservation protocols lower the blocking robability - caused by unavailable wavelengths or convergence problems of the network status information -, when compared to source initiated reservation protocols [1]. Choosing the wavelength using weights based on past performance may further lower such blocking probability, when compared to random selection strategies [2]. This paper presents a Destination initiated Weighted-Wavelength Reservation DW2R protocol that improves the performance of destination initiated reservation protocol and does not require any additional signaling messages. Wavelength weights are computed based on past blocking probabilities and stored at the source. A meticulous simulation study carried out on ring networks reveals for the first time a number of interesting properties of the proposed DW2 R protocol: a reduced (backward) blocking probability when compared to other reservation protocols, a good scalability in the number of ring nodes (links) and in the number of wavelengths, and a contained performance degradation due to an increase of either the ring signaling latency or the frequency of traffic changes.