Investigation of Optimum TTL Threshold value for Route Discovery in AODV

Abstract

In the mobile Ad hoc networking paradigm there is no fixed infrastructure and packets are delivered to their destinations through wireless multi hop connectivity. MANETs are in general characterized by mobile nodes with limited energy, constrained computing capability and absence of any base stations. Mobile nodes undertake role of routers engaging in some routing protocol required for deciding and maintaining the routes. MANET allows unrestricted mobility of the enlisted terminals as long as the least one terminal is within transmission range. Transmission range of wireless Adhoc network is restricted by its power consumption due to limited battery power of a wireless node. Reactive routing protocols are favoured in MANET's because they help in reducing overheads by continuously sending the data for better communication. These protocols suffer due to route discovery process. We focus on the problem of finding best search set of TTL(Time to live) values for expanding ring search to improve quality of service and evaluate performance of AODV by varying number of mobile nodes and nodes speed. Expanding ring search based on TTL in terms of early or delay in network flooding cause quality of service to fluctuate randomly. In this paper, early or delay in network flooding is employed to search for destination in a region limited by time to live (TTL). The performance of such expanding ring search schemes depends largely on TTL search sets. It is simulated using OPNET 14.5 simulator.