# Unmanned Aerial Vehicles Enabled IoT Platform for Disaster Management
## 4 Case Study: NDN Architecture for Ground IoT Network
### Proposed Methodology
#### 4.2.2 Average Response Time (ART)  
Figure 6 shows the relationship between the total number of nodes with respect to ART in wildfire disaster scenario. It compares two architectures, i.e., IP architecture (IP Arch.) and real-time proposed NDN (Pull-Push) architecture (NDN Arch.). The total number of NDN nodes were varied from 10 to 80. The ART is the ratio of the sum of total delay, i.e., propagation and transmission delays to the total time taken. It can be calculated as:  
\[ART=\frac{\sum^{N}(\tau_{p}+\tau_{t})}{T}, \tag{1}\]  
Figure 5: Implementation of the fire detection module.  
where \(\tau_{p}\) and \(\tau_{t}\) are the propagation and transmission delays, respectively; \(T\) is the total time taken in transmission; and \(N\) is the total number of consumer nodes. The result depicts that the proposed real-time NDN (Pull-Push) mechanism outperforms IP architecture in a wildfire disaster situation. Furthermore, the reason behind this overwhelming performance of NDN architecture is the unique data caching ability inside nodes, which is one of the major drawbacks of the traditional IP architecture. In wildfire, network nodes are scattered due to disaster; therefore, in the case of TCP/IP architecture, the source retransmits the information that is lost. On the other hand, NDN architecture recovers the required information from the NDN node's data structure, i.e., CS, PIT, and FIB. In this way, the NDN-based message communication in wildfire performs exceptionally as tit does not need to retransmit the information. Moreover, the IP architecture has higher network delay than NDN due to the retransmission of information from the source.  
Table 1 depicts the communication reliability of both architectures, i.e., (IP architecture and NDN architecture). We evaluated both architectures based on the percent wildfire disaster impact for 100 nodes, e.g.,  
* 10% disaster impact means 10 out of 100 nodes are defected; and
* 20% disaster impact means 20 out of 100 nodes are defected.  
However, as the disaster impact increases beyond 30%, the traditional IP architecture is unable to communicate between the nodes due to massive network damage. In contrast, NDN architecture still retains its message communication flow even at 50% disaster impact due to the caching ability inside the nodes. By adopting IP based mechanism, we do not have any suitable technique to recover information in a disastrous situation and the information is lost when the disaster impact crosses 50%. On the other hand, in NDN, we do not rely on end to end communication. Information is stored inside each node (CS, PIT and FIB) that is along the path and, therefore, we have multiple nodes to  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**\% Disaster Impact** & **IP Architecture** & **NDN Architecture** \\ \hline
10 & ✓ & ✓ \\
20 & ✓ & ✓ \\
30 & ✓ & ✓ \\
40 & ✗ & ✓ \\
50 & ✗ & ✓ \\ \hline \hline \end{tabular}
\end{table}
Table 1: Communication architecture reliability.  
Figure 6: Nodes average response time in wildfire scenario.  
recover information from instead of only the originator node as in case of the IP based system. Hence, with NDN, information can be recovered from any node along the path, even if the disaster impact crosses 50%. By considering the above results and analysis, it is concluded that the NDN architecture outperforms the IP architecture in real time wildfire situation and the NDN mechanism is more reliable, effective, and robust as compared to the traditional communication approaches.