| Summary: | 碩士 === 國立中正大學 === 通訊工程研究所 === 97 === As public demand for wireless network grows daily in the modern era, network mobility has rapidly increased along with the formation of Ad-hoc networks. In the past, wireless networks mainly used basic infrastructure networks, but due to improvements in wireless transmission equipment, convenience and mobility, demand for Mobile Ad-Hoc networks (MANETs) has rapidly increased. In MANET, the Optimized Link State Routing (OLSR) protocol requires each node to maintain on the network topology through the periodic exchange of network information. Once a change occurs in the network topology (link interruption or link establishment), one must wait for the periodic topology update to complete routing table updating. During this waiting process, the chance of package loss increases. Thus, our thesis proposed that the optimized link state routing to be modified as the basic Partial Fast-reroute for OLSR (PFRR-OLSR). Our method actively sends packets that search for possible alternate routes during the waiting period for periodic update and uses the responding packet signals to complete partial fast-rerouting for OLSR and redirecting the data flow. Finally, this study used NS2 to simulate and compared both the OLSR and the PFRR-OLSR in packet loss rate, recovery time, etc. The results of the simulation demonstrate that our scheme of PFRR-OLSR provides fast route update and greatly decreases packet loss rate. The decrease of packet loss in PFRR-OLSR is superior to that in OLSR more significant.
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