The role of network topologies in the optical core of IP-over-WDM networks with static wavelength routing

We present a performance analysis of network topologies for the optical core of IP-over-WDM networks with static wavelength routing. Regular degree four topologies are considered and the performance analysis is focused on chord lengths that lead to smallest diameters. For comparison purposes, degree three topologies are also considered. It is shown that the increase of the nodal degree from 3 (degree three topology with smallest diameter) to 4 (degree four topology with smallest diameter) improves the network performance if a larger number of wavelengths per link is available. However, the influence of wavelength interchange on the nodal degree gain is small. The performance of regular degree four topologies with smallest diameter is also compared with the performance of mesh-torus topologies (which are also degree four topologies), and it is shown that the blocking probability of degree four topologies with smallest diameter is about two orders of magnitude lower than the blocking probability of mesh-torus topologies.