Efficient Algorithms For Routing and Wavelength Assignment (ERWA) Under Dynamic Traffic in Survivable WDM Networks

摘要

Dynamic routing of a restorable connection necessitates the presence of a pair of link-disjoint primary and backup lightpaths online once a connection request arrives at the network. In this paper, we present efficient heuristics for routing and wavelength assignment (ERWA) for dynamic traffic in survivable WDM networks. It aims at minimizing the network cost as well as maximizing the resource utilization. Several previous works recommend a preemptive multi-class routing scheme, without considering the varying loads of dynamic traffic. For the routing part, this paper proposes a new distributed priority based routing algorithm intended for a variety of traffic classes, which employs the concept of load balancing to establish the primary and backup lightpaths. The proposed algorithm calculates the cost metric on the basis of the load on the links. The dynamic traffic can be classified into high and low priority. The routing of high priority traffic is performed over the lightly loaded links, in such a manner that the links with lighter loads are chosen instead of links with heavier-loads whilst routing the primary and backup paths. In addition, the resources can be shared between the high priority traffic's backup path and low priority traffic. For the wavelength assignment part, this paper proposes a heuristics which minimizes the number of wavelengths required for supporting the given traffic demand on any given topology. Based on the simulation results, it has been shown that by applying both the algorithms, the blocking probability and latency are reduced by means of increased throughput and channel utilization.