# A Study of MANET Routing Protocols in Heterogeneous Networks: A Review and Performance Comparison
## 5 Summary of Research Findings and Practical Implications  
There has been increasing research on mobile ad hoc networks (MANETs) and performance evaluation is performed by network simulators. A considerable number of studies show the importance of MANETs in critical emergencies. MANETs are wireless networks where the nodes are mobile constantly, and their infrastructures have no central routing resources in place. The nodes in heterogeneous MANETs have different resources and  
Figure 22: Packet delivery ratio for OLSR. capabilities for each node within the network. Heterogeneous MANETs have rarely been explored through network simulation tools, so this work helps to shed some light on the functionalities of heterogeneous networks. In this work, we analyze and compare four MANET routing protocols--AODV, OLSR, BATMAN, and DYMO--in a heterogeneous network environment. The simulations and evaluations of these protocols are conducted using the OMNeT++ simulator. The results are summarized next. * _End-to-end delay performance_ We have one abnormality that occurs during the test of AODV, which is the blue line. This is a mobile node. It does not follow the same arc as the other mobile hosts. We believe this to be because it was further away from the gateway and could not communicate with the gateway until it moved into range. We set the playground size for all these tests to 1 km. AODV reacted well, though, with its fixed nodes. The end-to-end delay was minuscule compared to the mobile hosts, which had a more significant delay in a talk at the beginning of the scenario. This could be due to AODV being a reactive protocol. DYMO is a hybrid protocol that can use both proactive and reactive routing protocols. For evaluating end-to-end delays, it would produce good results as it should be able to figure out what protocol is the best for this simulation. As we hypothesized, the graphs for DYMO show that it has a rapid connection time between end-to-end connections. The static hosts are extra fast yet again, followed closely by the mobile hosts. All the nodes stay below 0.02 except one mobile host, which initially takes a long time to send and receive the packets. As seen in the graph above, OLSR has terrible end-to-end delays. Both the mobile and fixed hosts have had the same problem. We believe this is due to the proactive nature of OLSR, causing the network to be flooded with control messages, which causes a more significant delay. BATMAN is a proactive routing protocol as well. It has been simulated with the same sort of results as OLSR. The network is flooded with so many control packets that it has slowed the network down. Two of the mobile hosts are intermittent because at 240 s into the simulation, this mobile host has moved to the edge of its transmission range. It also explains why it slowly increases and then comes back down. Since these hosts are not set to move in any set pattern, it has moved outside the range for a second and come back in at 260 s, so for 20 s, we have lost communication with this node. * _Throughput performance_ The DYMO and BATMAN fixed nodes proved to have a higher throughput rate than that of their predecessors, which is not surprising considering that both protocols share reactive and proactive routing capabilities. BATMAN's fixed nodes proved to have more packets delivered than the rest, whilst AODV and OLSR managed to deliver the most miniature packets. The same was the case with the mobile nodes. DYMO proved to have a better throughput rate in its mobile nodes than the other routing protocols. BATMAN had more of a variance in results than the rest of the protocols, particularly the spike in packet throughput midway through running the simulation. This happened with the fixed nodes and could only come down to the significance of the distance between the two nodes. Since there is high throughput, the nodes must be near each other in space.