Criticality avoidance routing in dynamic wavelength-routed optical networks

This paper solves the problem of path selection for WDM mesh networks with a special focus on the implementation in middle-sized networks, such as metropolitan-area networks (MANs). A novel routing and signaling protocol, called asynchronous criticality avoidance (ACA), is proposed to improve the network performance. With the ACA protocol, a specific set of wavelength channels are defined as "critical links" between a node pair according to dynamic link-state. The critical links and the associated link-states are also called criticality information, which are coordinated and disseminated by each source node to every other destination node as an inter-arrival planning. Routing and wavelength assignment is initiated and performed at the corresponding destination node, in which a criticality avoidance mechanism is devised to take the criticality information into consideration. Simulation is conducted in 22- and 30-node networks to examine the proposed approach. The simulation results show that the ACA protocol significantly outperforms the fixed-path least-congested (FPLC) and adaptive dynamic routing (ADR) schemes under the fixed alternate routing architecture. We conclude that the proposed ACA protocol can effectively reduce the resource fragmentation in wavelength-routed WDM networks without wavelength conversion.