# Supporting Heterogenous Traffic on Top of Point-to-Multipoint Light-Trees +
## 4 Illustrative Results
### Quantitative Analysis  
Let us first describe the scenario that we consider to analyze the performance of OCS and DSCM and compare it with a lightpath solution that uses traditional optical P2P coherent transceivers. We consider two types of traffic for 2 and 4 destinations: (i) P2P only and (ii) both P2P and P2 MP. For the study, the performance metrics analyzed are the number of required transceivers, the cost of deployment, and the efficiency. For the traditional P2P lightpath solution, the optical transceivers considered are 25 G, 50 G, 100 G, 200 G, and 400 G [22], whereas for OCS and DSCM technologies, we assume 600 G 64-QAM@64 GBd DP transceivers, as introduced in Section 4.1. Because in DSCM, receivers might have limitations in terms of the number of SCs they can process, two different availabilities are considered: (i) _non-aggressive_, which corresponds to the current status of P2 MP transceivers (e.g., [5]), where transmitters support 16 SCs for a total 600 G capacity, whereas receivers support 8 or 4 SCs for a total capacity of 300 G and 150 G,  
Figure 8: Details of optical performance of OCS (**a**) and DSCM (**b**). Figure 7: Optical system performance of OCS and DSCM for P2 MP. respectively, and (ii) _aggressive_, where both the sender and receivers have 600 G installed, which enables all the possible configurations. The summary of the configurations to be used in the rest of the paper are summarized in Table 2.  
Regarding traffic, we consider dynamic traffic scenarios where the capacity requested by destinations varies over time. In this case, a destination needs to support the maximum traffic of the traffic profile. Hence, destinations must require installing the optical transceiver that supports such a data rate or it must possess the capacity to dynamically manage the resource allocation according to the traffic profile. Figure 9a,b presents the traffic profiles under consideration for two and four destinations, respectively, for P2P traffic only and mixed P2P + P2 MP traffic. We observe that P2P traffic varies over the day [23], with some destinations requiring more capacity during day light (8 h-18 h), whereas other require more traffic during the night (18 h-8 h). As for the P2 MP traffic, we assumed a constant 100 Gb/s capacity throughout the day. The total maximum capacity requirement in the pure P2P traffic scenario is 300 Gb/s, whereas in the mixed one it is 400 Gb/s. Considering the same traffic profile and transceivers' availability as described previously, Figure 10 represents savings in terms of the number of transceivers required for OCS and DSCM as compared to the P2P lightpath solution. For the P2P traffic scenario, both OCS and DSCM provide equal savings in both aggressive and non-aggressive availabilities. For 2 destinations, the reduction in transceivers is 25%, whereas for 4 destinations, it is 38%. However, for the P2P + P2 MP traffic scenario, we observe a different trend. In the aggressive availability, OCS and DSCM provide the same savings, i.e., 57% and 62% for 2 and 4 destinations, respectively. However, in non-aggressive availability, OCS outperforms DSCM, which provides 14% and 23% savings for 2 and 4 destinations, respectively, \begin{table}
\begin{tabular}{c c c} \hline \hline
**P2P** & **OCS** & **DSCM** \\ \hline
25 G & 600 G & 600 G \\
50 G & 64-QAM & 64-QAM \\
100 G & @64 GBd & @64 GBd \\
200 G & DP & DP \\
400 G & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Available transceivers for P2P, OCS, and DSCM. Figure 9: Traffic profiles for P2P and P2P + P2 MP traffic with 2 and 4 destinations. in comparison to 57% and 62% of OCS, i.e., 43% and 39% more savings, respectively. The reason behind these results is the additional number of transceivers required in DSCM to serve P2 MP traffic when the highest data rate transceiver type is not available at the leaves. Let us now analyze the optimal cost of OCS and DSCM transceivers to find where they start to provide cost savings and compare with the P2P lightpath solution.