Lightpath Reconfiguration in WDM Networks

Lightpath reconfiguration is a networking task that can be performed in order to improve resource utilization. The lightpath reconfiguration problem becomes nontrivial when a new set of lightpaths requires the release of resources previously seized by the (working) lightpaths currently in place, but, in order to ensure continuity of the traffic flow, the working lightpaths cannot be torn down before the new ones are set up. Under this condition the reconfiguration can fall into a deadlock state, and deadlocks can only be solved by temporary disruption of some connections. At this point, traffic disruptions are necessary, and network operators must compensate customers with penalty fees for the service disruption. In this paper we focus on minimizing the number of simultaneously disrupted connections at any time during the reconfiguration process. In this paper, we propose a mixed-integer program (MIP) model, an exact algorithm, and a heuristic for solving the problem considering our objective.