What is Wavelength Division Multiplexing (WDM)

Survivability is the ability of the network to withstand faults and attacks including equipment and link failures. The main goal of survivable network is to be able to perform fast recovering at as small cost as possible (i.e., using minimum resources). As wavelength routing network paves the way for network throughputs of possibly hundreds of Tb/s, network survivability assumes critical importance. A short network outage can lead to data losses of the order of several gigabits. Hence, protection, or dedicating spare resources in anticipation of faults, and rapid restoration of traffic upon detection of a fault are becoming increasingly important. In this paper, we will explore the state of the art in network survivability and corresponding network control issues.