Constraint-based path selection methods for on-demand provisioning in WDM networks

We propose a framework for decentralized path selection and on-demand wavelength channel provisioning in WDM networks with routing constraints. Within this framework, the path information of choice, such as transmission quality, reliability, policy and traffic conditions, is updated following a connection request, based on a local, autonomous and service-differentiated characterization of optical network elements. It is this local and autonomous network state information that makes our approach particularly suitable for distributed implementation, and applicable to optical network architectures and control protocols that support service level guarantees. To illustrate this, we study mesh networks consisting of transparent, short-reach networking segments interconnected by long-reach WDM links with electronically regenerative gateways, where different link types show different SNR degradation, reliability and delay. On the example of electronically regenerative gateways, we address a new class of constraint-based path selection problems, where a certain a type of network element can at the same time deteriorate and improve network performance; e.g. electronic regenerators improve optical path quality and can adapt to wavelengths, but induce delays or operational costs. The performance study has shown the capability of our methods to accommodate arbitrary number and type of optical path properties, related to different network architectures and services.