# Evolutionary Strategy for Practical Design of Passive Optical Networks
## 7 Conclusions  
We proposed a new approach based on GA for optimization of PON planning. Tests on a large-size scenario proved the potential of the tool. In addition, the obtained results for the proposed scenarios show that the adopted topology in each project has a direct influence on the total cost of the network deployment. The distributed topology type 1 (DTT1) presented the lowest implantation cost, followed closely by the distributed topology type 2 (DTT2). This fact is justified due to the greater amount of splitters (of access) used in the network, reducing the amount of last mile cables (which represents a considerable part of the total cost of implementation). However, splitters with large capacity have a high cost and need a large concentration of subscribers in order to dilute their cost among them. Therefore, the trend is that, in scenarios with few subscribers, access splitters with smaller capacities have lower related costs, which makes distributed solutions more adapted to these situations. It is then noted that there is a clear relationship between subscribers location, splitters, PON ports and optical cables. Regarding the optical power link budget, all the solutions found by GA are above the threshold, which means an adequate operation of the proposed GPON system. **Author Contributions:** Conceptualization, L.P.D., R.C.d.A.A.J. and K.D.R.A. ; methodology, L.P.D., R.C.d.A.A.J. and K.D.R.A. ; software, L.P.D. ; formal analysis, L.P.D., A.F.d.S., R.C.d.A.A.J. and K.D.R.A. ; data curation, L.P.D. and A.F.d.S. ; writing--original draft preparation, L.P.D., R.C.d.A.A.J., A.F.d.S. and K.D.R.A. ; writing--review and editing, L.P.D., R.C.d.A.A.J., A.F.d.S., H.A.P. and K.D.R.A. ; visualization, W.F.G. and R.T.d.S.J. ; supervision, K.D.R.A. ; project administration, K.D.R.A. ; funding acquisition, K.D.R.A., W.F.G. and R.T.d.S.J. All authors have read and agreed to the published version of the manuscript. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multicolumn{6}{c}{**Region I (NDS)**} & \multicolumn{6}{c}{**Region I (DS)**} \\ \cline{2-10}
**Item** & **CTT1** & **CTT2** & **DTT1** & **DTT2** & **CTT1** & **CTT2** & **DTT1** & **DTT2** \\ \hline Execution time (min) & 25.14 & 31.52 & 27.13 & 33.62 & 19.21 & 35.12 & 27.14 & 29.02 \\
2F cable (drop cable) (km) & 26.98 & 26.46 & 21.65 & 12.78 & 78.09 & 60.99 & 48.67 & 40.35 \\
12F cable (distribution cable) (km) & - & - & 6.78 & 11.09 & - & - & 12.22 & 22.65 \\
48F cable (feeder cable) (km) & 6.58 & 6.64 & 2.05 & 2.99 & 9.83 & 11.57 & 7.31 & 7.16 \\ Total used optical cables (km) & 33.56 & 33.10 & 30.49 & 26.86 & 87.92 & 72.56 & 68.19 & 70.16 \\ Total used 1 st level splitters (unit) & 16 & 8 & 8 & 8 & 32 & 24 & 28 & 24 \\ Total used 2 nd level splitters (unit) & - & 16 & 21 & 38 & - & 47 & 86 & 138 \\ Total used FOSC (unit) & 16 & 16 & 7 & 8 & 32 & 47 & 22 & 22 \\ Total used PON ports (unit) & 16 & 8 & 8 & 8 & 32 & 24 & 28 & 24 \\ Network total cost (RS) & 430,122.38 & 406,639.48 & 371,720.02 & 385,718.94 & 1,294,399.87 & 1,261,623.09 & 1,259,180.97 & 1,312,597,11 \\ Increased cost (\%) & 13.58 & 8.59 & - & 3.63 & 2.72 & 0.19 & - & 4.06 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Comparison of the main information generated by the genetic algorithm for the four possible topologies, considering non-dense and dense scenario, for Region I.