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

SAFAR: An Adaptive Bandwidth-Efficient Routing Protocol 21We measure the performance of the SAFAR protocol against the following performancemetrics:Fig. 4. Number of nodes in proactive zonevs Standard deviation of BandwidthSize of the Proactive ZoneSince the proactive zone is adaptive,the size of the proactive zonevaries according to the node’s bandwidthand also its neighborhood. Weshow change in average size of theproactive zone of the node with varyingstandard deviations of bandwidthunder fairly constant average bandwidth.The graph (Fig. 4), shows thevariations in number of nodes queriedby a node for proactive maintenanceduring a simulation run to the standarddeviations of bandwidth. Each node in the simulation run is given a differentbandwidth value, with the standard deviation of all 50 nodes being shown in thegraph. The average bandwidth of nodes remains constant. As shown in Fig. 4,it has been found that the maximum number of nodes queried shows a sharpincrease with increase in standard deviation of bandwidth. This is to be expectedsince with a larger standard deviation, there will be nodes whose bandwidth isfar greater than its surroundings.Thus the factor F(fitness) increases and it queries more nodes. The averagenumber of nodes remains fairly constant(as expected), since the averagebandwidth is held constant. However, the difference between the average andmaximum value shows a steady increase. This shows that the fitness functionallows adaptive table buildup.Type-1 SuccessThis is a measure of the percentage ofsuccessful routes discovered in stage1 of routing. It is measured againstbandwidth of the node that initiatesthis node discovery.For analyzing the Type-1 successratio, nodes of different bandwidthvalues are analyzed as theytry to route packets to random destinations.The percentages of such requeststhat are successful are logged.As seen in Fig. 5, the Type-1 successratio increases with the bandwidthas expected. The graph alsoshows that a very high percentage ofdestinations are found with a Type-1Fig. 5. Percentage of Type-1 queries successfulvs Node Bandwidth