DiR: a resource-efficient framework for achieving reliable connectivity

Differentiated Reliability (DiR) is a concept that was recently introduced by the authors. The DiR concept can be applied to provide multiple reliability degrees (or classes) at the same network layer, using a desired protection scheme, e.g., dedicated path protection switching. According to the DiR concept, each connection is guaranteed a minimum reliability degree, or equivalently a maximum downtime ratio, that is chosen by the client. The reliability degree chosen for a given connection is thus determined by the application requirements, independently by the actual network topology, design constraints, robustness of the network components, and span of the connection. In this paper, two protection schemes are used to provide DiR in a WDM network with arbitrary topology: the path protection scheme and the partial path protection scheme. With either scheme, differentiation of reliability is successfully achieved. It is noted that the latter scheme is 10% more resource efficient than the former scheme in providing the desired reliability level. The former scheme is however less complex to manage than the latter.