## 4 Experiments and Results
### Experimental Results  
In this paper, the performance of the proposed ZSM technique was evaluated through comparative experiments with the hybrid technique PAST-DM and the security zone-based technique MSZRP. The following four performance indicators related to multicast transmission were used. For each performance indicator, the evaluation was performed according to the number of nodes, source nodes, and the multicast group size. 1. Packet transmission rate: The ratio of the number of transmitted data packets and the number of arrived data packets. It evaluates the efficiency of delivering the ability and data of the protocol, which discovers paths and maintains them to a destination node. 2. Number of control packets: It means the rate of control packets generated for data transmission. This includes packets used for route maintenance and packets transmitted in order to update node location information and maintain group membership. 3. Average path length: It is the average length of the path discovered by the protocol for the source node to the destination node. The average number of hops for each data packet to reach the destination node is calculated. 4. Average path delay: The time required to find a path from the source node to the destination node. It means the average delay between sending a path request packet and receiving the corresponding path response packet. Figures 6 and 7 evaluate the protocol performance for route management, where the number of multicast group nodes is fixed at 15 and changes dynamically according to the total number of nodes. Figures 6a and 7a present the packet transmission rate results. In all three techniques, an increase in node movement speed led to higher link breaks and packet drop rates, resulting in a reduced packet transmission rate. PAST-DM showed the lowest performance due to its difficulty in tracking and adapting to node movements, as well as its longer processing time. The MSZRP technique showed good results, benefiting from its ability to transmit the same data at once, while the ZSM technique demonstrated favorable outcomes by utilizing node information through GNT, even with node mobility. In Figures 6b and 7b, PAST-DM appeared slightly higher than both MSZRP and ZSM. This is because PAST-DM broadcasts route requests and responses and periodically updates the route from the source node to the destination node. Each time the PAST-DM mesh changes, the subtree structure must be gradually adapted, whereas such overhead does not occur in the ZSM technique. Additionally, while both MSZRP and ZSM techniques use similar dynamic routing management methods for nodes within a region, they differ in the way node information is exchanged between regions. In the ZSM technique, since request packets are transmitted between group management nodes, the result is a smaller amount of control packets. All three techniques showed an increase in control packets as the node mobility and the number of nodes increased, due to link failures and route recovery. Figures 6c and 7c show the results of the average path length. MSZRP broadcasts multicast route requests to collect routes from the receiving nodes within the group. How \begin{table}
\begin{tabular}{c c} \hline
**Parameter** & **Value** \\ \hline Network size & 1000 m \(\times\) 1000 m \\ Number of nodes & 50, 80 \\ Speed & 0–20 m/s \\ Pause time (sec) & 10 \\ Multicast group size & 15, 30 \\ MAC protocol & IEEE 802.11 DCF \\ Packet size & 512 bytes \\ \hline \end{tabular}
\end{table} 
Table 2: Simulation parameters. ever, the ZSM technique relies on route information provided by the inter-domain group management nodes, resulting in better performance compared to MSZRP. Figure 6: Experimental results for 50 nodes. (**a**) Packet delivery rate; (**b**) number of control packets; (**c**) average path length; (**d**) average path delay. Figure 7: Experimental results for 80 nodes. (**a**) Packet delivery rate; (**b**) number of control packets; (**c**) average path length; (**d**) average path delay.