Novel Caching Mechanism to Improve Performance in Mobile Ad-hoc Networks (MANETs)

摘要

MANET is a type of Ad-hoc network that has frequently changing topology due to mobility of nodes. Routing protocols that are developed for traditional wired and wireless networks does not suitable for MANET, therefore several routing protocols have been developed for MANETs. Routing protocols that have been developed for MANETs are categorized in to proactive, reactive and hybrid protocols, among those protocols Ad-hoc On-Demand Distance Vector (AODV) protocol and Dynamic Source Routing (DSR) protocol are the popular reactive routing protocols used in MANET.AODV performs better than DSR protocol. Even though AODV performs better than DSR, AODV need improvements. Researchers have identified that in order to discover routes AODV use broadcasting RREQ packets. This broadcasting process is costly in terms of delay, bandwidth. Whenever route failure occurs need to done this route discover process again. Due to this process lot of delay and overhead will occur to the data transmission. In order to minimize the effect of this RREQ broadcasting process researchers have implemented a route caching mechanism for AODV protocol by providing nodes with extra cache space, make necessary changes to the RREQ packet to carry node address and sequence number, make necessary changes to extract information and use that information whenever needed. In this modified protocol whenever route failure has occurred, node which detects a route failure try to repair route using cached routes. Simulation have been done using NS2 against AODV protocol and DSR protocol in terms of throughput, delay and packet delivery ratio, simulation results show that the modified AODV protocol performs better than the current on demand routing protocol which are AODV and DSR protocol.