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Topology embedding enables one to execute a protocol designed for a specific (virtual) topology on another (real) topology by embedding the virtual topology on the real topology. In this paper, we propose a self-stabilizing emulation technique that provides reliable communication on a virtual topology in the presence of transient faults in real topology. The proposed protocol improves the execution slowdown of previous two protocols [19, 20] and provides adaptive message delivery delay on the emulated channels, which is a new type of adaptability against transient faults.

Wavelength division multiplexing (WDM) networks have become a viable solution to meet the increasing bandwidth demand. These networks carry messages in the optical domain at data rates of several Gb/s. Such high data rates make it necessary for using efficient restoration protocols in an event of a failure. This paper addresses the problem of dynamic path-based restoration in WDM optical networks. Our objective is to develop a protocol that ensures rapid recovery while keeping the restoration ratio high. We propose two distributed dynamic restoration protocols called disjoint path-wavelength grouping protocol and disjoint weighted path-wavelength grouping protocol. Both these protocols group all the candidate backup paths of the failed paths into path-disjoint groups before assigning wavelengths to them. This allows the failed paths to search different sets of wavelengths on various candidate backup paths in parallel without any reservation conflicts. Also, it does not require any reservation retries, thus resulting in rapid restoration. The grouping method attempts to restore increased number of failed paths by allowing increased number of wavelengths to be searched on a path. The performance of the proposed protocol is verified through extensive simulation experiments.