Protection and Restoration from Link Failures in DWDM Networks: A Cross-Layer Study

Protection against failure in high bandwidth optical networks can prevent significant potential losses of data but at the same time it requires a considerable fraction of the network resources to be reserved for it. Moreover, in optical networks suffering from physical layer impairments, inefficient use of network resources leads to significant increase in the blocking probability and higher vulnerability due to degradation of the QoT (quality of transmission) in the network. These trade offs call for the need to consider the physical layer impairments in designing higher layer protection schemes, i.e., a QoT-aware or cross-layer design. In this paper, we look at the performance of several link protection and link and path restoration algorithms in all-optical networks with realistic physical layer impairments, and propose a new cross-layer restoration method that exhibits both low blocking probability and low vulnerability ratio.