On the Routing and Wavelength Assignment in Multifiber WDM Networks

Static RWA in All-Optical Network under Multifiber, Multiple Requests Assumption

“…Link-Based [5] (and [1]), and [6] Path-Based [7], [8], and [9] Heuristics [8], [10], and [11] Link-based approach was presented in [5] and again in B. Mukherjee's book [1], and also more recently in [6]. The idea is to formulate the problem as a Multi-Commodity Flow (MCF) problem, where each connection request is considered as a different commodity.…”

“…The models were solved by using Lagrangian multipliers to relax some of the constraints and using LPrelaxation. Another technique was presented in [8], where the authors address the Max-RWA problem for multiple requests and under multi-fiber assumption. The authors presented an ILP formulation for the problem, and provide a heuristics solution based on Max-Coverage theorem that guarantees the quality of the solution.…”

“…A common approach to target NP-Complete problems is based on heuristics as in [8], [10], and [11]. In these approaches the solution quality is traded for the techniques' complexity.…”

“…First, we address the more general case of multi-fiber links. Unlike, the formulation in [8], where handling the case of multi-fibers was part of the ILP formulation itself, we propose a modification in the phase of candidate path pre-calculation, where a certain link can be reused in this calculation as many times as the fiber multiplicity. In other words, physical fiber links are differently used within the same network span.…”

“…This assumption is of reasonable practical value due to its economical advantage; in practice it is of less cost to add more fibers (in a bundle) to already existing links rather than to construct new links [8]. Moreover, most installed fiber links are composed of multi-core fiber (where different fibers already co-exist, but not all used), and thus the suggested addition in our solution would correspond to the lighting of some dark (unused) fibers.…”