# Development of a Social DTN for Message Communication between SNS Group Members
## 5 Evaluation
### Operation Test of the Social DTN Manager  
To verify the operation of the experimental application, we created and shared a community token through linkage with Facebook and established a route between the source node and the destination  
Figure 7: Graphical user interface (GUI) examples of the social DTN manager application developed. (**a**) GUI layout for linkage to Facebook after a community token has been created; (**b**) Message type selection dialog for sending text or files.  
node. A character string or an image file registered by the source node was sent to the destination node. The specifications of the terminals used in the experiment are shown in Table 8. The structure of the experimental network is shown in Figure 8. The source node, the destination node and 1 to 4 relay nodes were laid out along a line 100 m long or 250 m long. All terminals had the same community token. The source node and the destination node were fixed, and relay nodes were carried by persons, who walked at a speed of about 5 km/h. A 55-kilobyte-character string was created at the source node and sent to the destination node. A 1-Mbyte image file was also sent.  
An example of sending text from the source node for the first time is described below along with terminal display images.  
The user taps \"Text\" on the screen shown in Figure 7b. The user enters a character string on the screen in Figure 9a, and taps \"OK.\" If the routing table of the source node has no information about the destination node address, the source node suspends discovery operation and starts advertising operation. Thus, an rreq_m is broadcast.  
When a relay node starts the application and starts discovery operation, the screen shown in Figure 9b is displayed. When the relay node discovers the rreq_m, it attempts to set up a connection to the terminal that has sent the rreq_m. After this connection is set up, the relay node receives the rreq_m and recognizes that it is a relay node. To forward the rreq_m, the relay node starts advertising operation as shown in Figure 9c.  
When the destination node starts the application and starts discovery operation (Figure 9b), it discovers the rreq_m being broadcast, and attempts to set up a connection to the relay node. After  
Figure 8: Structure of the experimental network.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Terminal Model** & **OS Version** & **Usage** \\ \hline Nexus5 & Android 7.1.2 & Source node \\ \hline HUAWEI Y6 SCL-L02 & Android 7.1.2 & Relay node \\ IMEI:861105030008770 & & \\ \hline HUAWEI Y6 SCL-L02 & Android 7.1.2 & Relay node \\ IMEI:861105030097666 & & \\ \hline BLUEDOT BNP-500 & & \\ Serial: ZLY5 CUNNQS6 HUWK7 & & \\ \hline BLUEDOT BNP-500 & & \\ Serial: OVTSEV79 QQ4 HZT8D & & \\ \hline NEC PC-TE507 FAW & Android 6.0.1 & Destination node \\ \hline \hline \end{tabular}
\end{table}
Table 8: Specifications of the terminals used in the experiment.  
this connection is set up, the destination node receives the rreQ_m, recognizes that it is the destination node, creates an rreP_m, and starts advertising operation (Figure 9c).  
When the relay node discovers rreP_m (Figure 9b), it checks whether its routing table has information about the destination of that message. If it has, it establishes an ad hoc connection to the terminal that has sent the rreP_m. After that, it receives the rreP_m, recognizes that it is a relay node, and starts advertising operation to forward the rreP_m (Figure 9c).  
When the source node receives the rreP_m, it sends to the destination node a dsnD_m that contains the text input by the user. We confirmed that the destination node successfully received that message.