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Journal of Emerging Technologies in Web Intelligence Contents

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JOURNAL OF EMERGING TECHNOLOGIES IN WEB INTELLIGENCE, VOL. 2, NO. 2, MAY 2010 87node through broadcast<strong>in</strong>g pr<strong>in</strong>ciple and an expand<strong>in</strong>g time tolive (TTL) timer. Foragers, the ma<strong>in</strong> workers.The architecture <strong>of</strong> the hive is shown <strong>in</strong> Fig 1 where theentrance floor is an <strong>in</strong>terface to the lower MAC layer, while thepack<strong>in</strong>g floor is an <strong>in</strong>terface to the upper transport layer. Thedance floor conta<strong>in</strong>s the foragers and the rout<strong>in</strong>g <strong>in</strong>formation toroute locally generated packets. The functional characteristics <strong>of</strong>each floor compos<strong>in</strong>g the hive are expla<strong>in</strong>ed <strong>in</strong> the follow<strong>in</strong>g.floor from the MAC layer. If the packet is the forager and th ecurrent node is its dest<strong>in</strong>ation, then the forager is forwarded tothe pack<strong>in</strong>g floor.; otherwise, it is directly routed to the MAC<strong>in</strong>terface <strong>of</strong> the next hop node. If the packet is a scout, it isbroadcast to the neighbor nodes if its TTL timer has not expiredyet or if the current node is not its dest<strong>in</strong>ation. The <strong>in</strong>formationabout the ID <strong>of</strong> the scout and its source node is stored <strong>in</strong> a locallist. If a replica <strong>of</strong> previously received scout arrives at theentrance floor , it is removed from the system. If a forager withthe same dest<strong>in</strong>ation as the scout already exists on the dancefloor, then the forager’s route to the dest<strong>in</strong>ation is given to thescout by append<strong>in</strong>g it to the route held so far by the scout.Fig 1. Overview <strong>of</strong> BeeAdHoc ArchitectureVI. PACKING FLOORThe pack<strong>in</strong>g floor is an <strong>in</strong>terface to the upper transport layer(e.g, TCP or UDP) . Once a data packet arrives from transportlayer, a match<strong>in</strong>g forager for it is looked up on the danced floor .If a forager is found then the data packet is encapsulated <strong>in</strong> itspayload . Otherwise, the data packet is temporary bufferedwait<strong>in</strong>g for a return<strong>in</strong>g forager. If no forager comes back with<strong>in</strong>a certa<strong>in</strong> predef<strong>in</strong>ed time, a scout is launched which isresponsible for discover<strong>in</strong>g new routes to the packet dest<strong>in</strong>ation .Figure 2 expla<strong>in</strong>s the series <strong>of</strong> action performed at pack<strong>in</strong>g floor.Fig 3: The EntranceVIII. DANCE FLOORFig 2 : The Pack<strong>in</strong>g FloorVII. ENTRANCEThe function performed <strong>in</strong> the entrance are shown <strong>in</strong> figure.3. The entrance is an <strong>in</strong>terface to the lower level MAC layer.The entrance handles all <strong>in</strong>com<strong>in</strong>g and out go<strong>in</strong>g packet. Actionon the dance floor depends on the type <strong>of</strong> packet entered theThe dance floor is the heart <strong>of</strong> the hive because it ma<strong>in</strong>ta<strong>in</strong>sthe rout<strong>in</strong>g <strong>in</strong>formation <strong>in</strong> the form <strong>of</strong> foragers. The dance flooris populated with rout<strong>in</strong>g <strong>in</strong>formation by means <strong>of</strong> mechanismrem<strong>in</strong>iscent <strong>of</strong> the waggle dance recruitment <strong>in</strong> natural bee hivesonce a forager returns after its journey, it recruits new forager by“danc<strong>in</strong>g” accord<strong>in</strong>g to the quality <strong>of</strong> the path it traversed.A lifetime forager evaluates the quality <strong>of</strong> its route based onthe average rema<strong>in</strong><strong>in</strong>g battery capacity <strong>of</strong> the nodes along itsroute. The central activity <strong>of</strong> the dance floor module consists <strong>of</strong>send<strong>in</strong>g a match<strong>in</strong>g forager to the pack<strong>in</strong>g floor <strong>in</strong> response to arequest from a packer. The foragers whose lifetime has expiredare not considered for match<strong>in</strong>g. If multiple path be identifiedfor match<strong>in</strong>g, then a forager is selected <strong>in</strong> a random way. Thishelps <strong>in</strong> distribut<strong>in</strong>g the packets over multiple paths, which <strong>in</strong>turn serves two purpose : avoid<strong>in</strong>g congestion under high loadsand deplet<strong>in</strong>g batteries <strong>of</strong> different nodes at comparable rate. Aclone <strong>of</strong> the selected forager is sent to the pack<strong>in</strong>g floor and thenumber <strong>of</strong> permitted clones. If the dance number is 0 then theorig<strong>in</strong>al forager is sent to the pack<strong>in</strong>g floor remov<strong>in</strong>g it <strong>in</strong> thisway from the dance floor. This strategy aims at favor<strong>in</strong>g youngover old foragers.If the last forager for a dest<strong>in</strong>ation leaves ahive then the hive does not have any more route to thedest<strong>in</strong>ation. Nevertheless if a route to the des<strong>in</strong>ation still existsthen soon a forager will be return<strong>in</strong>g to the hive if no foragercomes back with<strong>in</strong> reasonable amount <strong>of</strong> time, then the node has© 2010 ACADEMY PUBLISHER

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