# Delay Bounded Multi-Source Multicast in Software-Defined Networking
## 6 Performance Evaluations
### Small Real Networks  
Under this subsection, we implement our algorithm on real network called Biznet. In order to observe the performance of DBMS in total delay cost and execution time, we compare it with the solution of the MILP model which is solved using the IBM ILOG CPLEX Optimizer [37]. CPLEX is able to find optimal solutions for small instances for our MILP problem. Biznet is available on the internet topology zoo at [[http://www.topology-zoo.org/dataset.html](http://www.topology-zoo.org/dataset.html)]([http://www.topology-zoo.org/dataset.html](http://www.topology-zoo.org/dataset.html)). The potential source nodes set \(|S|\) spans from 2 to 10 and destination nodes set \(|D|\) from 5 to 13. We also compare the performance of our DBMS scheme with that of mRAERA, SPT and ST.  
Figure 4a shows that in general, as the number of source nodes increases from 2 to 6, the execution time decrease for all the algorithms. The execution time that the SDN controller will take to create the DBMS-Forest reduces because more source nodes enables more destination nodes to connect to the suitable sources faster. As the number of source nodes increases, the probability of more destination nodes being closer to those source nodes becomes higher as well, and hence less links from source to destination node. Our DBMS scheme performs much better than the mRAERA, ST and SPT. The execution time of DBMS is very closer to the optimal solution generated by CPLEX.  
We can deduce from Figure 4b that increasing the number of destination nodes increases the total cost delay. As the number of destination nodes increases from 5 to 13, more links are being added to the multicast trees, meaning that the trees generated will be larger. DBMS scheme still manage to find better minimum total delay cost compared to mRAERA, SPT and ST. The total delay cost solution generated by DBMS is very closer to the optimal solution. On the other hand, the total delay cost can be reduced by increasing the number of source nodes as demonstrated by Figure 5. DBMS scheme utilizes the delay bound effect to insure that only the destination-source nodes pair with the minimum delay cost are connected. As the number of source nodes increases from 2 to 10, the total delay cost for mRAERA, SPT and ST decrease as well, but at a slower frequency compered to the DBMS. This demonstrate the positive effects of DBMS on SDN multicast as the number of source node increases. The DBMS solution is very similar to the optimal solution in this regard and reduces the total cost by about 34% when compared to mRAERA.  
\begin{table}
\begin{tabular}{l l} \hline \hline
**Item** & **Description/ Value** \\ \hline Graph type & Partially mesh \\ Network scale & 4000 to 10,000 nodes \\ Weighted matrix selection method & Random \\ Source-destination selection & Random \\ Number of shortest delay path between source-destination & 1 \\ Deployment cost of each node & 1 \\ Number of _source nodes_ & 2 to 60 \\ Number of _destination nodes_ & 5 to 100 \\ Capacity of each node & 1 \\ Delay bound (\(\delta\)) & 40 ms to 9000 ms \\ \hline \hline \end{tabular}
\end{table}
Table 5: Experiment Parameters.