An algorithm for virtual topology design in WDM optical networks under physical constraints

Although designing a virtual topology for all-optical WDM wide-area networks has been extensively studied and several algorithms have been proposed, these algorithms assume error-free communication between two nodes. However, noises from optical amplifiers and optical cross-connects can degrade the signal, resulting in a nonzero bit-error rate. In this paper, we investigate the effect of physical limitations on the virtual topology design. We show that for wide-area all-optical networks where transmission distance is fairly long, virtual topology design algorithms must take physical limitations into account to ensure a low bit-error rate. We also propose a heuristic algorithm that can determine the locations of opto-electronic (OE) and electro-optic (EO) conversions to set up a connection request with a high BER in a multihop manner