## 6 Simulation Results
### Simulation Results Analysis  
First, the network resources that would be occupied by applying three different algorithms to carry the same traffic requests are analyzed in Figure 5. The traffic rate sum of 50 traffic requests is set to 200 Tb/s. In the simple mesh network topology, 69 SLs (1792 SBs) are occupied when the LBMSA algorithm is applied to carry all traffic requests, 123 SLs (3235 SBs) are occupied when the KSP algorithm is applied, and 123 SLs (3115 SBs) are occupied when KSP-CNs algorithm is applied. In the Japan network topology, 58 SLs (1257 SBs), 99 SLs (2394 SBs), and 105 SLs (2382 SBs) are occupied by applying the LBMSA algorithm, KSP algorithm, and the KSP-CNs algorithm, respectively. Moreover, in the NSF network topology, the occupied network resources are 135 SLs (3610 SBs), 170 SLs (4495 SBs), and 170 SLs (4495 SBs) by applying the LBMSA algorithm, KSP, and KSP-CNs algorithm, respectively. It can be seen that by using the LBMSA algorithm, as few SLs and SBs as possible are occupied to carry the traffic requests. When simulating the simple mesh network topology and the Japan network topology, using the LBMSA algorithm saves almost half of the network resources, compared to the latter two algorithms. Furthermore, in the NSF network topology, using the LBMSA algorithm also saves about 20% of SLs and SBs, compared to the latter two algorithms. The above simulation results show that the LBMSA algorithm can allocate the least amount of network resources to carry the traffic requests by setting CNs and performing MFC. In addition, in Figure 5, the NSF network topology with the largest average SDM link length occupies more network resources because the less efficient MFs are used. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Network Topology** & **Number of Nodes** & **Number of SDM** & **Average SDM Link** \\  & **Nodes** & **Links** & **Length (km)** \\ \hline Simple Mesh Network & 9 & 13 & 1062.60 \\ Japan Network & 12 & 17 & 436.76 \\ NSF Network & 14 & 22 & 1936.36 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Characteristics of the simulated network topology. Figure 5: (**a**) The number of occupied SLs and SBs for the LBMSA algorithm, the KSP algorithm, and the KSP-CNs algorithm in the simple mesh network; (**b**) The number of occupied SLs and SBs for the LBMSA algorithm, the KSP algorithm, and the KSP-CNs algorithm in the Japan network; (**c**) The number of occupied SLs and SBs for the LBMSA algorithm, the KSP algorithm, and the KSP-CNs algorithm in the NSF network. The simulation results of the KSP algorithm and the KSP-CNs algorithm are analyzed and compared in Figure 5. In the simple mesh network topology, the same number of SLs are assigned to the traffic requests using both algorithms, but the number of occupied SBs using the KSP algorithm is 4% more than that using the KSP-CNs algorithm. This is because the KSP-CNs algorithm saves spectrum resources by setting CNs, dividing routing paths into shorter-length MFSs, and selecting more efficient MFs. In the Japan network topology, there is little difference in the number of network resources used to carry the traffic requests using the two algorithms, due to the large variance in SDM link lengths. Applying the MF of the longest MFS to the entire routing path does not necessarily reduce the occupied network resources and may have the opposite effect. In the NSF network topology, although the optimization results of both algorithms are the same, the indexes and numbers of SLs and SBs assigned to the same traffic request are not the same because SA is used to optimize the sum of the network resources occupied by all traffic requests. In Figure 6, the occupancy of SLs and SBs using the three algorithms is analyzed under different traffic loads. Different traffic request sets are constructed by varying the traffic rate without changing the number of traffic requests inside each set.