# Traffic-Based Heuristics for Regenerator Placement in Translucent Dynamic Optical Networks
## 6 Results
Figure 8 (Figure 9) shows BP as a function of the total number of regenerators installed in the CoreNet (EuroNet) topology. under UT and total offered load of 600 erl (500 erl). Figure 8a (Figure 9a) stands for the comparison between the BPs verified using \(k=3\) (shown as closed symbols) against the ones verified for \(k=1\) (shown as lines), whereas Figure 8b (Figure 9b) stands for the comparison between the BPs verified using \(k=5\) (closed symbols) against the ones verified for \(k=1\) (lines). As expected, the greater the value of \(k\) considered, the lower the BP achieved by a given algorithm. In all investigated cases, the DLD algorithm remains the best cost-effective strategy to solve RPP regardless of the value of \(k\) selected. It means that, for a given number o regenerators, the DLD strategy always returns lower or equal BP when compared to the other strategies. Moreover, note that the relative performance of the algorithms, in terms of BP, remains almost unaltered by comparing their BPs results with \(k=1\) against the BPs results using either \(k=3\) or \(k=5\). It means that, for a given value of \(R\), the algorithm that returns the lowest BP for \(k=1\) also returns the lowest BP for both \(k=3\) and \(k=5\). The same occurs with the algorithm that returns the second-lowest BP and so on. There are some exceptions, such as the comparison between ND and RO in CoreNet for a large number of 3R installed. The performance of the RPP algorithms for different transparent reaches is also investigated. For this purpose, we have decided to show the results for the best (in terms of BP) 4 algorithms investigated so far: ND, RR, FLD, and DLD. We investigate the algorithms performance assuming 3 different transmissions reaches \(T_{R}\): \(T_{R}=1600\) km, \(2000\) km, and \(2400\) km. Notice that the \(T_{R}\) is an input parameter for the RPP algorithms RR, FLD, and DLD, as it is taken into account during the RPP procedure. Thus, different values of \(T_{R}\) require different execution of RR, FLD, and DLD. Figure 8: Blocking probability as a function of the total number of regenerators in CoreNet topology using k-shortest path routing algorithm for: (**a**) \(k=3\); (**b**) \(k=5\), each compared against the \(k=1\) case. Figure 7: Blocking probability as a function of the total load in EuroNet topology using 504 regenerators and traffic: (**a**) uniform and (**b**) non uniform. Figure 10 (Figure 11) shows BP as a function of the total number of regenerators installed in the CoreNet (EuroNet) topology under a uniform traffic and total offered load of 600 erl (500 erl). Figure 10a (Figure 11a) stands for the comparison between the BP verified assuming \(T_{R}\) = 1600 km (shown as closed symbols) against the one verified for \(T_{R}\) = 2000 km (shown as lines), whereas Figure 10b (Figure 11b) stands for the comparison between the BP verified assuming \(T_{R}\) = 2400 km (closed symbols) against the one verified for \(T_{R}\) = 2000 km (lines). As expected, the greater the value of \(T_{R}\) considered, the lower the BP achieved by a given algorithm. In all investigated cases, the DLD algorithm remains the best cost-effective strategy to solve RPP regardless of the value of \(T_{R}\) selected. It means that, for a given number o regenerators, the DLD strategy always returns lower or equal BP when compared against the other strategies assuming the same \(T_{R}\). On the other hand, the relative performance of the algorithms, ND, RR, and FLD, in terms of BP, shows significant dependence on the assumed \(T_{R}\), mainly for a moderate/high number of regenerators installed in the network. In CoreNet, FLD and RR return almost the same values of BP in the entire considered range for \(R\) assuming both \(T_{R}\) = 1600 km and \(T_{R}\) = 2000 km (Figure 10a), whereas RR returns a slightly lower BP than FLD for \(T_{R}\) = 2400 km and moderate values of \(R\) (Figure 10b). The most significant inversions are verified for the EuroNet.