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Page 2 Lecture Notes in Computer Science 2865 Edited by G. Goos ...

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Proactive QoS Rout<strong>in</strong>g <strong>in</strong> Ad Hoc Networks 65Table 3. OPNET Model Parameter.OLSRHello Interval 0.5sParameters TC Interval 2sData Rate2 MbpsWirelessBuffer Size256000 bitsLANRetry Limit 7ParametersWireless LAN Propagation Range250 MThe OPNET simulation results are grouped <strong>in</strong>to two sets: Basic Performance andQoS Performance (The data shown <strong>in</strong> this section are the average value from multipleruns.)Basic Performance – the basic performance is measured <strong>by</strong> a set of metrics used toevaluate most rout<strong>in</strong>g protocols: “Packet Delivery Ratio” and “End to End Delay”.Packet Delivery Ratio: percentage of packets that successfully reach the receiv<strong>in</strong>gnodes each second.End to End Delay: the average time between a packet be<strong>in</strong>g sent and be<strong>in</strong>g receivedQoS performance – metrics that relate to the bandwidth QoS rout<strong>in</strong>g studied <strong>in</strong> thispaper: “Error Rate” and “Bandwidth Difference”.Error Rate: the percentage of times the rout<strong>in</strong>g algorithms do not f<strong>in</strong>d the optimalbandwidth path.Bandwidth Difference: the average difference between the optimal bandwidth andthe detected non-optimal bandwidth <strong>in</strong> percentage.106.00%101.00%96.00%91.00%86.00%81.00%76.00%71.00%66.00%20m/s 10m/s 5m/s 1m/s 0m/sQoS 20% 66.89% 75.71% 84.66% 90.89% 98.15%QoS 40% 67.59% 79.21% 88.05% 94.31% 99.53%QoS 80% 72.05% 79.91% 89.46% 93.44% 97.58%Orig<strong>in</strong>al 75.75% 82.30% 87.81% 96.34% 96.56%QoS 20%QoS 40%QoS 80%Orig<strong>in</strong>alFig. 2. Packet Delivery Ratio under different movement patterns.Fig. 2 compares the packet delivery ratio of the 4 algorithms. From high movementto low movement, packet delivery ratio for all algorithms rises cont<strong>in</strong>uously. Withlower movement, the established l<strong>in</strong>ks between the nodes have a lower probability ofbreak<strong>in</strong>g, thus, there are less stale routes <strong>in</strong> the node rout<strong>in</strong>g tables, which results <strong>in</strong> ahigher ratio for correct packet delivery. In low movement scenarios (speed 5m/s,1m/s and 0m/s), the 4 algorithms achieve similar packet delivery ratio. However, <strong>in</strong>high movement scenario, the orig<strong>in</strong>al OLSR protocol has higher packet delivery ratio

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