# An Improved Hybrid Routing Protocol Combining MANET and DTN
## 4 Performance Evaluation
As can be expected, AODV has the smallest delivery latency, but PRoPHET has the largest delivery latency since delivery latency is calculated for the successfully delivered messages only, as shown in Equation (6). The proposed protocol has larger  
Figure 5: Delivery ratio for varying number of nodes. AODV = ad hoc on-demand distance vector ; HSBR = hybrid social based routing algorithm. Figure 6: Overhead ratio for varying number of nodes. delivery latency than AODV but smaller delivery latency than PRoPHET. The proposed protocol has similar delivery latency with HSBR. The results shows that the effect of threshold values on the delivery latency is not significant. Figure 8 shows delivery ratio for varying the speed of nodes from U[0.0,0.5] (m/s) to U[4.5,5.0] (m/s) with different threshold values, i.e., 0, 0.1, 0.2, 0.4, and 0.8, when the number of node is 60. Since the number of nodes is fixed as 60, the proposed protocol with high values of delta has the largest delivery ratio and AODV has the smallest delivery ratio. When the speed of nodes increases, delivery ratio sharply increases, but it has similar values when the speed of nodes is not very small. Therefore, the effect of the speed of nodes is not significant when the mobility of nodes is not so small to contact with other nodes after movement. Figure 9 shows overhead ratio for varying the speed of nodes from U[0.0,0.5] (m/s) to U[4.5,5.0] (m/s) with different threshold values, i.e., 0, 0.1, 0.2, 0.4, and 0.8, when the number of node is 60. AODV has the smallest overhead ratio, and then HSBR has the second smallest overhead ratio. In the proposed protocol, the proposed protocol with large values of delta has high overhead ratio due to  
Figure 8: Delivery ratio for varying speed of nodes. Figure 7: Delivery latency for varying number of nodes. more message dissemination, and the proposed protocol with small values of delta has small overhead ratio due to less message dissemination. The proposed protocol when the value of delta is 0 has a similar overhead ration with HSBR. The result shows that the proposed protocol has higher overhead ratio due to more message dissemination, when the value of delta is not so small. Figure 10 shows delivery latency for varying the speed of nodes from U[0.0,0.5] (m/s) to U[4.5,5.0] (m/s) with different threshold values, i.e., 0, 0.1, 0.2, 0.4, and 0.8, when the number of node is 60. The delivery latency of AODV is smallest and the delivery latency of PRoPHET is largest when the speed of nodes is U[0.5,1.0] (m/s), which is a default setting, as shown from Figure 7. When the speed of nodes increases, however, the delivery latency of AODV is higher than other protocols since topology is not stable in high speed environment and thus most of the message delivery in AODV is achieved using direct delivery when it contacts the destination node directly. On the other hand, the delivery latency of other protocols based on DTN protocol is smaller than AODV when the speed of nodes is high and it decreases as the speed of nodes increases because of more contact with other nodes. The proposed protocol has similar delivery latency with HSBR. The results shows that the effect of threshold values on the delivery latency is not significant. Figure 10: Delivery latency for varying speed of nodes. Figure 9: Overhead ratio for varying speed of nodes.