# A Survey on Parameters Affecting MANET Performance
## 5 Related Work  
An abundance of the literature covered the effect of changing different environmental parameters on MANETs' performance. Statistical analyses regarding the topics covered by the researchers and the areas which require more attention in the future are performed. All selected references share in common the AODV routing protocol. AODV protocol is one of the widely used routing protocols in MANETs [49] as it has a wide range of advantages compared with other protocols. AODV is loop-free and scales to a large number of nodes, is adaptable to topology changes and responds to changes quickly, supports both unicast and multicast transmissions, has a minimal routing overhead, and has lower setup delay [50]. Some researchers conduct a performance analysis comparison between the AODV routing protocol and other routing protocols such as OLSR and DSR protocols, while other researchers focus on the performance of the AODV protocol under attack. A part of the literature contribution focuses on analyzing the effect of changing some parameters, such as mobility speed or network density, to analyze the effect of changing such parameters on the AODV protocol. Furthermore, other researchers propose enhancements to existing protocols while others propose new mechanisms for routing. The current survey is based on 50 recent papers that share in common the AODV routing protocol. Table 6 summarizes the used routing protocol parameters within the scope of collected papers. Out of 50 papers, only five references covered the effect of changing routing protocol parameters on the overall performance. As shown in Table 7, the percentage of the usage of routing protocols in MANETs does not exceed 6% of the literature contribution. Other routing parameters that are not mentioned in Table 6 were not used in the current survey papers. More focus and contributions are needed from the literature to address the effect of changing the routing parameters. Figure 7: The different evaluation metrics used in MANETs. Some researchers analyzed the effect of attacking the MANET routing protocol under different environments and attack scenarios. As shown in Table 8, the literature has placed more focus on blackhole and grayhole attacks. Based on a study of the most common attacks on the MANET network layer [52], the study shows that blackhole and grayhole attacks are globally introduced to affect MANETs and they also have a high impact on MANET performance. Table 8 compares the simulation and attack parameters used in the collected papers. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Reference Name** & **Routing Protocol** & **Network Area** & **Node Diameter** & **RREQ** & **Max RREQ** & **Active Route Timeout** & **Delete Period Timeout** \\ \hline Observation of AODV Routing Protocol’s Performance at Variation in ART Value for Various Node’s Mobility [15] & AODV & x & x & x & - & x & x \\ \hline Impact of Active Route Time Out and Delete Period Constant on AODV Performance [18] & AODV, DSR & - & - & - & - & x & x \\ \hline Comparative Performance Analysis of AODV for CRR and V VBR Traffic under Influence of ART and DPC [23] & AODV, OLSR & - & - & - & - & x & x \\ \hline Performance Optimization of MANET Networks through Routing Protocol Analysis [51] & AODV, OLSR & - & - & x & x & - & - \\ \hline \hline \end{tabular}
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Table 6: Survey on routing parameter usage in MANETs. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Routing Parameter** & **Papers** & **Percentage of Usage** \\ \hline Network diameter & 1 of 50 & 2\% \\ \hline Node transversal time & 1 of 50 & 2\% \\ \hline RREQ retries & 2 of 50 & 4\% \\ \hline Max RREQ timeout & 1 of 50 & 2\% \\ \hline Active route timeout & 3 of 50 & 6\% \\ \hline Delete period & 3 of 50 & 6\% \\ \hline Other parameters & 0 of 50 & 0\% \\ \hline \hline \end{tabular}
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