Sample Solution

The wavelength-selective ROADM architecture, or WSS architecture, is colorless even though it uses arrayed waveguide grating (AWGs) rather than wavelength selective switches (WSSs). This is because AWGs are designed to be essentially transparent to any signal that passes through them, meaning that they act as two-way passageways and do not interfere with the wavelengths of the signals passing through. This means that when a signal reaches an AWG at a certain wavelength, it will not be affected by its presence and can effectively bypass it on its journey.

In contrast, a 1:4 protection for the four primary WSSs would require a modification of this broadcast-and-select ROADM architecture at degree two nodes in order to provide protection from failure. In such an instance one spare WSS must be added along with four primary ones; each set up specifically for each direction of communication (i.e., eastward and westward). The eastward path requires four inputs with one output going towards the drop port while the westward path requires one input coming from the add port and four outputs going outwards into the network (Hou et al., 2019).

Once implemented within this modified architecture these five WSSs can then be used in unison to establish higher levels of reliability by providing redundant paths which are capable of taking over should any single component fail along either transmission route. This technique provides significant benefits as compared to using just one switch within such networks since if there was only one component failures could potentially cause entire links being lost until service was restored.