# MMNET: A Multi-Modal Network Architecture for Underwater Networking
## 4 Study Case  
Through the introduction of MMNET, we have a certain degree of understanding of MMNET recommendations for UWSNs. Here is a study case to deepen our understanding of this. As shown in Figure 12, there are two types of underwater scenes. One is the underwater environment monitoring (completed by fixed sensor nodes) and the other is underwater data collection. AUV is mainly responsible for underwater data collection. Underwater environmental monitoring includes two types of forwarding networks and two types of heterogeneous networks. The Figure 13 shows the network equipment and network protocol carried by each network node, and its communication process. Figure 11: The network manager allocates network resources to applications. Figure 10: New virtual devices or functions join the network. Underwater environmental monitoring includes two types of forwarding networks and two types of heterogeneous networks. As shown in Figure 14b, in order to monitor the underwater environment information, fixed nodes will be equipped with CTD, temperature and salinity depth, dissolved oxygen and other sensors. These sensor data are triggered by timing tasks. After the timing tasks are triggered, as shown in Figure 14a, the network management program will extract the characteristics of the tasks, recommend the network resources according to the characteristics of the tasks, and then apply for network resources according to the recommended network configuration and configure them. After the network configuration is completed, the underwater environment information will be uploaded  
Figure 12: Case study for the MMNET. This study case includes four kinds of nodes: Ground node, water surface node, autonomous underwater vehicle (AUV) and underwater node. Each node runs one or two applications (APPs). Each node may carry radio frequency, acoustic, optical and magnetic induction (MI). At the same time, each node carries address-based routing and name-based routing. Figure 13: Status and information of each network node. according to the time. After receiving the data from the underwater, the water node will send the wireless telex to the surface application. As shown in Figure 15b, when the underwater environment information changes, in order to confirm the specific changes of the underwater environment, as shown in the Figure 15a, the network management program will extract the characteristics of the task, recommend the network resources according to the characteristics of the task, then apply for the network resources according to the recommended network configuration, configure the network to be named based on the routing and forwarding strategy, and send interest After receiving the interest packet, the underwater node will upload the data package that meets the requirements to help the surface application to study and judge the environmental conditions. Underwater data collection network includes two kinds of forwarding networks and three kinds of heterogeneous networks. Figure 14: (**a**) Application process of network resources for timed tasks; (**b**) detailed information of interaction between timed task terminals in underwater environment monitoring network. Figure 15: (**a**) Emergency data request for underwater detection application; (**b**) detailed information of interaction between emergency task terminals of underwater environmental monitoring network. As shown in Figure 16b, when the underwater data collection is not urgent, the AUV will cruise underwater to collect data, and the AUV node will locate with the surface node through the acoustic network. After the AUV data collection is completed, as shown in Figure 16a, the network management program will extract the characteristics of the task, recommend the network resources according to the characteristics of the task, and then apply for the network resources according to the recommended network configuration. The data exchange between AUV and the surface node is carried out through optical or magnetic communication.