mitter Fixed 0.5 dB IM MZ LiNbO3 dynamic range Linear crosstalk Depends on the OXC number 0.22 + Noxc dB Gaussian AWG FWM and XPM Depends on the number of spans 0.012 + Nspan dB 70 km span Residual DGD Depends on the number of spans See text Strong blind EDC and SPM Channels at 10 Gbit/s Strong blind EDC Polarization effects Fixed like a margin Aging Fixed like a margin System margin Fixed Next Generation Networking: Enabling Technologies, Architectures, and Performances A few observations on Table 10.4 are useful to underline differences between opaque and transparent networks from a transmission point of view. The first point concerns the optical bandwidth. While in a stand-alone system, this is a fixed parameter, here, due to fact that a cascading of filters generates a progressive reduc- tion of the bandwidth, the optical bandwidth and the ratio Moe depend on the number of filters traversed by the signal (in our case, this corresponds to twice the number of OXCs). The second observation concerns the impact of interaction between residual differential group delay (DGD) and SPM. Several attempts have been made to derive a phenomeno- logical curve that matches the dependence by the span number and the span length for a reasonable configuration of the system. However, this depends in a non-negligible way on the general system parameters, first of all on the fiber type and the modulation chirp. Probably, the only way to face this point is to repeat this evaluation every time a parameter changes. It is in any case evident that transmission in a transparent network cannot be planned a priori in an effective manner as in an opaque network both for the fact that the wavelength path routes are not a priori known and also for the influence of InB crosstalk that adds up along the path every time an OXC is traversed. 10.3.5.5 Example of Network Design and Role of Wavelength Converters We would like to close the considerations about cyclic algorithms with an example of their use. The computational complexity of a cyclic al