Dynamic lightpath restoration based on bidirectional initiation for wavelength-routed WDM networks

Dynamic restoration is one of the basic survivability paradigms for surviving single-link failures in wavelength-routed wavelength division multiplexing (WDM) networks. In dynamic restoration, no spare network resources are reserved before a network failure occurs. The network must dynamically discover spare network resources to recover the disrupted network services after a network failure occurs. Accordingly, dynamic restoration is efficient in resource utilisation but slow in service recovery. Fast provisioning of service recovery is a great concern with dynamic restoration. A bidirectional initiation restoration mechanism (BIRM) is proposed for dynamic path restoration in wavelength-routed WDM networks. BIRM differs from existing path restoration mechanisms in that it allows both the source node and the destination node of a broken lightpath to respectively initiate a path restoration process in the event of a link failure. The purpose is to reduce the path restoration time so that a backup path can be established quickly for each broken lightpath that traverses a failed link. Based on fIRM, a dynamic path restoration protocol is also presented. Moreover, the performance of BIRM is evaluated through simulation experiments in terms of the path restoration time and request blocking probability.