## 2 Related Work
### Classification of Multicast Protocols  
In MANET, multicast protocols are classified into tree-based, mesh-based, and hybrid approaches based on how the distribution paths are constructed among group members [4]. Tree-based multicast constructs a tree that connects the source node to the destination nodes in the multicast group to facilitate data transmission. This approach ensures that each destination node receives data without transmission through redundant paths [9]. By doing so, it conserves network bandwidth and avoids the delivery of duplicate packets to destination nodes. Tree-based multicast protocols dynamically update the tree structure to adapt to changes in network topology. They must rebuild the tree when destination nodes or other nodes join or leave the network. By establishing the optimal path for data reception, tree-based multicast efficiently utilizes network resources such as bandwidth, power, and processing capacity, thereby minimizing resource waste. Tree-based multicast can be categorized into source-based tree, shared tree, dynamic source-based tree, and mesh-based tree. Examples include source tree multicast [10], core-based tree [11], and AMRIS (adaptive mesh-based multicast routing) [12]. Table 1 presents a comparative analysis of the characteristics of tree-based multicast techniques. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Characteristic** & **Advantage** & **Disadvantage** \\ \hline \multirow{4}{*}{Source-based tree} & A structure in which the source & & & The tree structure expands \\  & node acts as the root of the & & The path is clear and path & inefficiently or path \\  & multicast tree and data are & optimization is possible & re-configuration becomes \\  & transmitted from the source node & & frequent. \\  & to all destination nodes. & & Efficient management of & \\ \hline \multirow{3}{*}{Shared tree} & A method where multiple source & & & \\  & nodes share a common tree & & & \\  & structure for data transmission & & & \\  & & & & \\ \hline \multirow{2}{*}{Dynamic source-based tree} & A method where a new tree is & & & Overhead arises due to \\  & constructed each time the source & & & frequent tree \\  & node transmits data & & & reconfigurations \\ \hline \multirow{3}{*}{Mesh-based tree} & A structure that uses multiple & & & \\  & simultaneous paths, enhancing & & & \\ \cline{1-1}  & path stability and accommodating & & & \\ \cline{1-1}  & mobility more effectively & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison of tree-based multicast features. Mesh-based protocols utilize multiple paths between the source and destination nodes for data transmission. While simultaneous use of multiple paths may result in redundant transmissions, these protocols effectively handle node mobility and minimize packet loss [13]. However, a notable drawback is the high resource consumption caused by path redundancy. AMRIS (adaptive mesh-based multicast routing) employs an adaptive approach and dynamically selects and updates paths based on the connectivity between destination nodes or network changes [14]. This protocol is flexible in handling path failures and remains efficient even as the network size increases. ODMRP (on-demand multicast routing protocol) is an on-demand multicast protocol that dynamically establishes transmission paths whereby it initiates a route request when the source node intends to send multicast packets [15]. It transmits data in a mesh structure, utilizing multiple paths simultaneously. Each destination node selects one among the multiple paths receiving the multicast messages for data reception. ODMRP achieves low overhead by dynamically requesting route establishment only when needed; MTR (multicast tree-based routing with mesh) combines tree-based and mesh-based approaches [16]. The source node establishes a tree-based path and simultaneously employs additional mesh paths for data transmission. This hybrid approach enables rapid response to path disruptions.