# An Efficient Delay Tolerant Networks Routing Protocol for Information-Centric Networking
## 4 Performance Analysis  
In this paper, the Data delivery probability and Data overhead are compared by varying the values of buffer sizes, TTL of Data, and number of relay nodes by simulation using opportunistic network environment (ONE) simulator [27]. The Data delivery probability and Data overhead are defined as follows:  
\[\textit{Data delivery probability}=\frac{1}{N_{total}(D)}\sum_{i=1}^{N_{total}(D)} \frac{N_{delivered}(i)}{N_{requesters}(i)}, \tag{5}\]  
\[\textit{Data overhead}=\frac{1}{N_{total}(D)}\sum_{i=1}^{N_{total}(D)}\frac{N_ {relayed}(i)}{N_{delivered}(i)}, \tag{6}\]  
where \(N_{total}(D)\), \(N_{delivered}(i)\), and \(N_{relayed}(i)\) are total number of requested Data IDs, number of delivered Data for Data ID \(i\), and number of relayed Data for Data \(i\), respectively. Table 2 shows parameter values used in the simulation. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **CIDOR Protocol** & **OF Protocol** & **Proposed Protocol** \\ \hline \multirow{4}{*}{Interest forwarding} & Epidemic protocol (total number of copies: 10 copies) & Extended PRoPHET protocol by using the delivery predictability to a set of nodes caching the requested Data & Sharing of requester information in status table \\ \cline{2-4}  & & Extended PRoPHET protocol by using the protocol by using the average delivery predictability to a set of requesters & Extended PRoPHET protocol by using the average delivery predictability to a set of requesters \\ \hline \multirow{4}{*}{Overhead control of Data} & Limitation of replications to 10 copies in Spray phase & None & Reduction of unnecessary forwarding of Data using satisfaction flag in status table \\ \cline{2-4}  & & & flag in status table \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison of CIDOR and the proposed protocol. Figure 5 shows Data delivery probability for varying buffer sizes. The delivery probability increases as buffer sizes increases, and it saturates when the buffer sizes is sufficient. This is because more Data can be accommodated in the buffer and more Data can be delivered without dropping due to buffer overflow, as buffer sizes increases. When the buffer sizes is sufficient, the effect of increasing buffer sizes is not significant and thus the delivery probability saturates. The proposed protocol has higher delivery probability than both CIDOR and OF protocols, especially for higher buffer sizes. The proposed protocol has maximum 34% of increase than CIDOR protocol and has maximum 105% of increase than OF protocol. This is because effective forwarding of Data based on efficient requester ID management and effective overhead control using satisfaction flag achieve efficient Interest and Data delivery. Figure 6 shows Data overhead for varying buffer sizes. The Data overhead decreases as buffer sizes increases, and it saturates when the buffer size is sufficient. This is because more Data can be accommodated in buffer for larger buffer sizes and thus additional Data forwarding due to dropped Data by buffer overflow decreases more. The OF protocol has higher Data overhead in most of the \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Simulation time (s) & 43,200 \\ \hline Transmit speed (Mbps) & 2 \\ \hline Transmit range (m) & 10 \\ \hline Buffer size (Mbytes) & 10–55 (default: 30) \\ \hline \multirow{3}{*}{Number of nodes} & Requester: 50 \\  & Original Data caching node: 10 \\  & Relay node: 10–100 (default: 50) \\ \hline Speed of nodes (m/s) & U [0.5, 1.5] \\ \hline Mobility model & Shortest Path Map Based Movement \\ \hline \multirow{3}{*}{Message size (Mbytes)} & Interest: 0.001 \\  & Data: U [0.5, 1.0] \\ \hline Interest generation interval (s) & U [25; 35] \\ \hline Number of Data & 100 \\ \hline TTL (minutes) & Interest: 90 \\  & Data: 15–150 (default: 90) \\ \hline Cache replacement policy of CS & FIFO \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Parameter values. Figure 5: Data delivery probability for varying buffer sizes.