## 4 Experiments and Results
### Experimental Results
Figures 6d and 7d show the average path delay results. In PAST-DM, the path selection changes each time refinement occurs during the adaptation of the subtree, leading to higher delays. MSZRP, considering security and reliability, requires additional checks such as security status verification and exclusion of suspicious paths, which contributes to higher delays. ZSM, by receiving route requests and response packets through the group management nodes, showed better results than the other two techniques. The efficiency of the multicast protocol, along with the increase in the number of multicast groups in the network, was also measured. Figure 8 presents the experimental results for performance metrics in a scenario with 80 total nodes and two multicast groups, each of size 15. Figure 8a shows the results for the packet delivery ratio of the three techniques. PAST-DM, using a virtual mesh topology, exhibited a lower packet delivery ratio due to frequent mesh adjustments in response to increases in multicast groups and dynamic changes in nodes. MSZRP, which exchanges routing information through nodes within the region, was not significantly affected by the size of the multicast groups. The ZSM technique, which does not periodically transmit packets and efficiently manages node information within the region, demonstrated the best performance in packet delivery, showing minimal impact from the number of multicast groups. Figure 8b shows that the number of control packets increased across all three techniques as the number of multicast groups grew. This also impacted the average path delay, as illustrated in Figure 8d. PAST-DM experienced an increase due to the periodic transmission of packets. The ZSM technique was affected by packets related to the management of group member nodes within the region. The results for the average path length associated with the selected path are shown in Figure 8c,d. In Figure 8d, PAST-DM showed an immediate activation of path setup; however, as the number of multicast member nodes increased, the route request and response  
Figure 8: Experimental results for two source nodes. (**a**) Packet delivery rate; (**b**) number of control packets; (**c**) average path length; (**d**) average path delay. packets increased due to the dynamic topology, which scaled with the number of nodes. MSZRP and ZSM showed results influenced by regional information sharing and dynamic adaptability. Figures 9 and 10 present the performance metrics measured according to the size of the multicast group to evaluate the scalability of the three techniques. As seen in Figures 9a and 10a, PAST-DM exhibits poor scalability compared to the other two techniques due to frequent broadcasting across the network. In contrast, the ZSM technique exhibits better scalability than PAST-DM, as group management nodes periodically handle the management of member nodes within the region. Both the MSZRP and ZSM techniques, which are region-based, showed similar results concerning multicast group size. Figures 9b and 10b show that as the multicast group size increases, the number of broadcast route request and response packets also rises. Additionally, the route between the source and receiving nodes must be periodically updated, leading to more control packets. Consequently, MSZRP and ZSM demonstrated better scalability than PAST-DM. The size of the multicast group did not have a significant impact on the average path length, as shown in Figures 9c and 10c. Figures 9d and 10d present the results for the average path length measurement. As the number of multicast group member nodes that must receive packets from the source node increases, the overhead for path maintenance also increases, which in turn causes an increase in the average path delay for all three techniques. Table 3 shows the averages of the four performance metrics obtained from the experiments, providing an overview of the performance of each protocol. Figure 9: Experimental results for 15 multicast group sizes.