An Adaptive Reliable Multipath Centralized RWA Algorithm for All-Optical WDM Networks

Balancing the load among multiple paths leads to the degradation in the all-optical WDM network. It is always desirable to deliver the entire load on a single optimal path depending upon the current network-wide load status. For this case, multiple light paths need to be maintained to provide the choice of selecting the best light path, based on the changing traffic load conditions, This paper presents the design and analysis of an adaptive reliable multipath centralized routing algorithm (ARMCR) with two central management systems (CMS-1 and CMS-2) which considers load heuristic for selecting the optimal and backup paths. Initially in this algorithm when a request comes to a source it sends the information to CMS-1 for allocating the optimal primary and backup paths for the received request, depending on the number of available free wavelengths. With the assigned primary path, source starts clearing the request meanwhile CMS-2 keeps track of the changes in the available free wavelengths and failure of all the paths. In the assigned primary path if the available free wavelength number comes below the threshold number 'N‘ and at the same time if any other path is available with more number of free wavelengths, then CMS-2 assigns this path as primary path and very next more number available free wavelengths path is assigned as backup path. The advantage of this algorithm is that it reduces the set up time by using two CMS which share the work and also if one fails the other will take over the entire process. As opposed to the reactive protocols, our proposed protocol is proactive in the sense that it avoids the chances of blocking. Furthermore, the approach is self-regulating, it automatically adapts to the traffic load variation across the network. By simulation results, we showed that our proposed protocol has low set up time and blocking.