بلقيس رعد عبداللطيف
Abstract
The AODV routing protocol is based on blind flooding for route request packets (RREQ) dissemination in the route discovery mechanism. which can result in the same packet being received multiple times by the same nodes. Unnecessary packet forwarding “re-transmission” will lead to network congestion and packet collision which are collectively known as the "Broadcast Storm Problem". In this work, the suggested protocol named Enhanced Neighbor Protocol “ENP” is a distance-based protocol employed to collect the data for the 2-hop-neighbour of all nodes. This information is important for selecting any node be it “forwarder” or not. Another notable approach is dominant pruning (DP) which is a distributed dominant set algorithm developed to mitigate the impact of flooding in MANETs. The dominant pruning (DP) requires 2-hop neighbor information. This information can be collected with the help of the neighbor discovery protocol.
The threshold values are set depending on these metrics (data delivery, overhead, and link broke). These metrics are partially or totally conflicted with each other, i.e. the best data delivery achieved with a specific set of thresholds can incur the worst overhead. Therefore, the selection of threshold must attain a compromise among the conflicting metrics. In this work, the Multi-Objective Particle Swarm Optimization (MOPSO) was investigated and applied as the selection tool for the optimum threshold distances for each considered network size. There is no single solution that concurrently optimize all of the objectives for MOPSO. The objective functions are conflicting in that situation. The resulting solutions represent the best solutions known as "Non-dominated solutions”. The aim may be to discover a representing set of "Pareto optimal solutions", and estimate the tradeoffs among various objectives (data deliver, link broke, and overhead).
ENP(Enhanced Neighbor Protocol) has been employed in conjunction with DP and both have incorporated AODV routing protocol to illustrate the advantages "ENP" of the protocol for different network sizes and a specific pair of threshold is selected with the aid of MOPSO approach. The performance of ENP/MOPSO was compared with the original periodically neighbor discovery protocol in conjunction with DP “AODV/DP” and traditional routing protocols “AODV and OLSR”. It was also compared with a previous work that depends the “multi-criteria decision making (MCDM)” approach as the selection tool.
